Soluble adenylyl cyclase, the cell-autonomous member of the family

Soluble adenylyl cyclase (sAC) is the evolutionarily most ancient of a set of 10 adenylyl cyclases (Adcys). While Adcy1 to Adcy9 are cAMP-producing enzymes that are activated by G-protein coupled receptors (GPCRs), Adcy10 (sAC) is an intracellular adenylyl cyclase. sAC plays a pivotal role in numerous cellular processes, ranging from basic physiological functions to complex signaling cascades. As a distinct member of the adenylyl cyclase family, sAC is not activated by GPCRs and stands apart due to its unique characteristics, regulation, and localization within cells. This minireview aims to honour Ulli Brandt, the outgoing Executive Editor of our journal, Biochimica Biophysica Acta (BBA), and longstanding Executive Editor of the BBA section Bioenergetics. We will therefore focus this review on bioenergetic aspects of sAC and, in addition, review some important recent general developments in the field of research on sAC.

Deciphering metabolic crosstalk in context: lessons from inflammatory diseases

Metabolism plays a crucial role in regulating the function of immune cells in both health and disease, with altered metabolism contributing to the pathogenesis of cancer and many inflammatory diseases. The local microenvironment has a profound impact on the metabolism of immune cells. Therefore, immunological and metabolic heterogeneity as well as the spatial organization of cells in tissues should be taken into account when studying immunometabolism. Here, we highlight challenges of investigating metabolic communication. Additionally, we review the capabilities and limitations of current technologies for studying metabolism in inflamed microenvironments, including single-cell omics techniques, flow cytometry-based methods (Met-Flow, single-cell energetic metabolism by profiling translation inhibition (SCENITH)), cytometry by time of flight (CyTOF), cellular indexing of transcriptomes and epitopes by sequencing (CITE-Seq), and mass spectrometry imaging. Considering the importance of metabolism in regulating immune cells in diseased states, we also discuss the applications of metabolomics in clinical research, as well as some hurdles to overcome to implement these techniques in standard clinical practice. Finally, we provide a flowchart to assist scientists in designing effective strategies to unravel immunometabolism in disease-relevant contexts.

Opposite regulation of glycogen metabolism by cAMP produced in the cytosol and at the plasma membrane

Cyclic AMP is produced in cells by two different types of adenylyl cyclases: at the plasma membrane by the transmembrane adenylyl cyclases (tmACs, ADCY1~ADCY9) and in the cytosol by the evolutionarily more conserved soluble adenylyl cyclase (sAC, ADCY10). By employing high-resolution extracellular flux analysis in HepG2 cells to study glycogen breakdown in real time, we showed that cAMP regulates glycogen metabolism in opposite directions depending on its location of synthesis within cells and the downstream cAMP effectors. While the canonical tmAC-cAMP-PKA signaling promotes glycogenolysis, we demonstrate here that the non-canonical sAC-cAMP-Epac1 signaling suppresses glycogenolysis. Mechanistically, suppression of sAC-cAMP-Epac1 leads to Ser-15 phosphorylation and thereby activation of the liver-form glycogen phosphorylase to promote glycogenolysis. Our findings highlight the importance of cAMP microdomain organization for distinct metabolic regulation and establish sAC as a novel regulator of glycogen metabolism.

Cholangiocytes express an isoform of soluble adenylyl cyclase that is N-linked glycosylated and secreted in extracellular vesicles

Soluble adenylyl cyclase (sAC)-derived cAMP regulates various cellular processes; however, the regulatory landscape mediating sAC protein levels remains underexplored. We consistently observed a 85 kD (sAC₈₅ ) or 75 kD (sAC₇₅ ) sAC protein band under glucose-sufficient or glucose-deprived states, respectively, in H69 cholangiocytes by immunoblotting. Deglycosylation by PNGase-F demonstrated that both sAC₇₅ and sAC₈₅ are N-linked glycosylated proteins with the same polypeptide backbone. Deglycosylation with Endo-H further revealed that sAC₇₅ and sAC₈₅ carry distinct sugar chains. We observed release of N-linked glycosylated sAC (sAC_EV ) in extracellular vesicles under conditions that support intracellular sAC₈₅ (glucose-sufficient) as opposed to sAC₇₅ (glucose-deprived) conditions. Consistently, disrupting the vesicular machinery affects the maturation of intracellular sAC and inhibits the release of sAC_EV into extracellular vesicles. The intracellular turnover of sAC₈₅ is extremely short (t_1/2 ~30 min) and release of sAC_EV in the medium was detected within 3 h. Our observations support the maturation and trafficking in cholangiocytes of an N-linked glycosylated sAC isoform that is rapidly released into extracellular vesicles.

Metabolic changes underlying drug resistance in the multiple myeloma tumor microenvironment

Multiple myeloma (MM) is characterized by the clonal expansion of malignant plasma cells in the bone marrow (BM). MM remains an incurable disease, with the majority of patients experiencing multiple relapses from different drugs. The MM tumor microenvironment (TME) and in particular bone-marrow stromal cells (BMSCs) play a crucial role in the development of drug resistance. Metabolic reprogramming is emerging as a hallmark of cancer that can potentially be exploited for cancer treatment. Recent studies show that metabolism is further adjusted in MM cells during the development of drug resistance. However, little is known about the role of BMSCs in inducing metabolic changes that are associated with drug resistance. In this Perspective, we summarize current knowledge concerning the metabolic reprogramming of MM, with a focus on those changes associated with drug resistance to the proteasome inhibitor Bortezomib (BTZ). In addition, we present proof-of-concept fluxomics (glucose isotope-tracing) and Seahorse data to show that co-culture of MM cells with BMSCs skews the metabolic phenotype of MM cells towards a drug-resistant phenotype, with increased oxidative phosphorylation (OXPHOS), serine synthesis pathway (SSP), TCA cycle and glutathione (GSH) synthesis. Given the crucial role of BMSCs in conveying drug resistance, insights into the metabolic interaction between MM and BMSCs may ultimately aid in the identification of novel metabolic targets that can be exploited for therapy.

ATP8B1 Deficiency Results in Elevated Mitochondrial Phosphatidylethanolamine Levels and Increased Mitochondrial Oxidative Phosphorylation in Human Hepatoma Cells

ATP8B1 is a phospholipid flippase that is deficient in patients with progressive familial intrahepatic cholestasis type 1 (PFIC1). PFIC1 patients suffer from severe liver disease but also present with dyslipidemia, including low plasma cholesterol, of yet unknown etiology. Here we show that ATP8B1 knockdown in HepG2 cells leads to a strong increase in the mitochondrial oxidative phosphorylation (OXPHOS) without a change in glycolysis. The enhanced OXPHOS coincides with elevated low-density lipoprotein receptor protein and increased mitochondrial fragmentation and phosphatidylethanolamine levels. Furthermore, expression of phosphatidylethanolamine N-methyltransferase, an enzyme that catalyzes the conversion of mitochondrial-derived phosphatidylethanolamine to phosphatidylcholine, was reduced in ATP8B1 knockdown cells. We conclude that ATP8B1 deficiency results in elevated mitochondrial PE levels that stimulate mitochondrial OXPHOS. The increased OXPHOS leads to elevated LDLR levels, which provides a possible explanation for the reduced plasma cholesterol levels in PFIC1 disease.

Innate Immune Training of Human Macrophages by Cathelicidin Analogs

Trained innate immunity can be induced in human macrophages by microbial ligands, but it is unknown if exposure to endogenous alarmins such as cathelicidins can have similar effects. Previously, we demonstrated sustained protection against infection by the chicken cathelicidin-2 analog DCATH-2. Thus, we assessed the capacity of cathelicidins to induce trained immunity. PMA-differentiated THP-1 (dTHP1) cells were trained with cathelicidin analogs for 24 hours and restimulated after a 3-day rest period. DCATH-2 training of dTHP-1 cells amplified their proinflammatory cytokine response when restimulated with TLR2/4 agonists. Trained cells displayed a biased cellular metabolism towards mTOR-dependent aerobic glycolysis and long-chain fatty acid accumulation and augmented microbicidal activity. DCATH-2-induced trained immunity was inhibited by histone acetylase inhibitors, suggesting epigenetic regulation, and depended on caveolae/lipid raft-mediated uptake, MAPK p38 and purinergic signaling. To our knowledge, this is the first report of trained immunity by host defense peptides.

Role of the IgG4-related cholangitis autoantigen annexin A11 in cholangiocyte protection

BACKGROUND & AIMS

Annexin A11 was identified as autoantigen in IgG4-related cholangitis (IRC), a B-cell driven disease. Annexin A11 modulates calcium-dependent exocytosis, a crucial mechanism for insertion of proteins into their target membranes. Human cholangiocytes form an apical 'biliary bicarbonate umbrella' regarded as defense against harmful hydrophobic bile acid influx. The bicarbonate secretory machinery comprises the chloride/bicarbonate exchanger AE2 and the chloride channel ANO1. We aimed to investigate the expression and function of annexin A11 in human cholangiocytes and a potential role of IgG1/IgG4-mediated autoreactivity against annexin A11 in the pathogenesis of IRC.

METHODS

Expression of annexin A11 in human liver was studied by immunohistochemistry and immunofluorescence. In human control and ANXA11 knockdown H69 cholangiocytes, intracellular pH, AE2 and ANO1 surface expression, and bile acid influx were examined using ratio microspectrofluorometry, cell surface biotinylation, and 22,23-3H-glycochenodeoxycholic acid permeation, respectively. The localization of annexin A11-mEmerald and ANO1-mCherry was investigated by live-cell microscopy in H69 cholangiocytes after incubation with IRC patient serum containing anti-annexin A11 IgG1/IgG4-autoantibodies or disease control serum.

RESULTS

Annexin A11 was strongly expressed in human cholangiocytes, but not hepatocytes. Knockdown of ANXA11 led to reduced plasma membrane expression of ANO1, but not AE2, alkalization of intracellular pH and uncontrolled bile acid influx. High intracellular calcium conditions led to annexin A11 membrane shift and colocalization with ANO1. Incubation with IRC patient serum inhibited annexin A11 membrane shift and reduced ANO1 surface expression.

CONCLUSION

Cholangiocellular annexin A11 mediates apical membrane abundance of the chloride channel ANO1, thereby supporting biliary bicarbonate secretion. Insertion is inhibited by IRC patient serum containing anti-annexin A11 IgG1/IgG4-autoantibodies. Anti-annexin A11 autoantibodies may contribute to the pathogenesis of IRC by weakening the 'biliary bicarbonate umbrella'.

LAY SUMMARY

We previously identified annexin A11 as a specific autoantigen in immunoglobulin G4-related cholangitis (IRC), a B-cell driven disease affecting the bile ducts. Human cholangiocytes are protected against harmful hydrophobic bile acid influx by a defense mechanism referred to as the 'biliary bicarbonate umbrella'. We found that annexin A11 is required for the formation of a robust bicarbonate umbrella. Binding of patient-derived annexin A11 autoantibodies inhibits annexin A11 function, possibly contributing to bile duct damage by weakening the biliary bicarbonate umbrella in patients with IRC.

P-321 The impact of endometrioma and ovarian cystectomy in patients with major indications for IVF/ICSI with endometriosis

Study question

Does presence of endometrioma has worse IVF/ICSI outcome than endometriosis per se? What about the impact of cystectomy of endometrioma on IVF/ICSI outcomes?

Summary answer

IVF/ICSI outcome of patients with endometrioma is comparable than with endometriosis. Cystectomy for endometrioma did not alter IVF/ICSI outcomes if ovarian reserve is comparable.

What is known already

Previous studies revealed women with endometrioma undergoing IVF/ICSI had similar reproductive outcomes compared with those without. Most of the comparisons are between women with endometrioma and women without endometriosis. However, endometrioma per se, different from endometriosis may have specific impact on IVF/ICSI outcomes. There is now molecular, histological and morphological evidence to suggest endometrioma is detrimental to the ovaries. Studies comparing IVF/ICSI outcomes between women with endometrioma and women with endometriosis are few.

Cystectomy of endometrioma may worse ovarian reserve, and subsequently adversely affect IVF/ICSI outcomes. But there are possible complications associated with the persistence of endometrioma during IVF/ICSI.

Study design, size, duration

Retrospective analysis of 2153 IVF/ICSI cases during Jan/01/2014 to Dec/31/2018 in VGHTC. We included women who received ART due to endometriosis(n = 208). Exclusion criteria including patients >40 years-old, simulation day < 5 days, severe male factor, uterine factor (including adenomyosis) and immunological factors. Patients whose embryos were not completely transferred back or who received embryo transfer from different OPU cycles are excluded. We followed up these patients till 2020/6. The primary outcome is cumulative LBR

Participants/materials, setting, methods

For first analysis, we divided 208 cases to patients with endometrioma during IVF/ICSI(n = 89), and patients only diagnosed of endometriosis (n = 119). Second analysis on the effect of cystectomy of endometrioma on IVF/ICSI outcomes. Patients with endometrioma (n = 89) during IVF/ICSI were further divided to patients with primary endometrioma (n = 70) and patients with recurrent endometrioma (n = 19, ever received cystectomy for endometrioma). Another group is patients without endometrioma during IVF/ICSI, but ever received cystectomy before (n = 40)

Main results and the role of chance

For the first analysis, age, BMI and AMH were comparable in endometrioma (n = 89) and endometriosis group(n = 119). The usage gonadotropin dose was significantly higher in the endometrioma group (FSH 3619IU vs 3471IU, p = 0.001. LH 1224 IU vs 941 IU, p = 0.009). The Blastocyst formation rate is lower in the endometrioma group (49.4% vs. 57.7% p = 0.005). The OPU number, LBR and cumulative LBR were comparable in both groups (10.3 vs 12.4 p = 0.131, 33.3% vs 37%, p = 0.687, 49.4% vs 60.5%, endometrioma vs endometriosis). For the second analysis, when comparing cystectomy before IVF/ICSI group with primary endometrioma group, cystectomy group were younger (32.8 vs 34.8 p = 0.006). AMH level were comparable. The BC formation rate was significantly higher in the cystectomy group (61.5% vs 50.4% 0= 0.007). The LBR and cumulative LBR were comparable in both groups (43.5% vs 28.1%, 60% vs 48% in cystectomy vs primary endometrioma group). As for the recurrent endometrioma group, the age and AMH level were comparable with cystectomy group, but the usage gonadotropin dose was significantly higher than other two groups. The BC formation rate was also lower than cystectomy group (47.8% vs 61.5% p = 0.042). The LBR and cumulative LBR were comparable with other two groups (55.6%, 57.9%).

Limitations, reasons for caution

This is a retrospective study, and the sample size is limit. We did not analysis the size of endometrioma nor the unilateral or bilateral endometrioma.

Wider implications of the findings

Cystectomy for endometrioma must be carefully selected since it did not alter IVF/ICSI outcome only if the ovarian reserve is not affected. Recurrent endometriomas do not have a worse impact on IVF/ICSI outcome than primary endometrioma. If there is recurrent endometrioma, IVF/ICSI may be the first priority.

Trial registration number

not applicable

P–321 The impact of endometrioma and ovarian cystectomy in patients with major indications for IVF/ICSI with endometriosis

Study question

Does presence of endometrioma has worse IVF/ICSI outcome than endometriosis per se? What about the impact of cystectomy of endometrioma on IVF/ICSI outcomes?

Summary answer

IVF/ICSI outcome of patients with endometrioma is comparable than with endometriosis. Cystectomy for endometrioma did not alter IVF/ICSI outcomes if ovarian reserve is comparable.

What is known already

Previous studies revealed women with endometrioma undergoing IVF/ICSI had similar reproductive outcomes compared with those without. Most of the comparisons are between women with endometrioma and women without endometriosis. However, endometrioma per se, different from endometriosis may have specific impact on IVF/ICSI outcomes. There is now molecular, histological and morphological evidence to suggest endometrioma is detrimental to the ovaries. Studies comparing IVF/ICSI outcomes between women with endometrioma and women with endometriosis are few.

Cystectomy of endometrioma may worse ovarian reserve, and subsequently adversely affect IVF/ICSI outcomes. But there are possible complications associated with the persistence of endometrioma during IVF/ICSI.

Study design, size, duration

Retrospective analysis of 2153 IVF/ICSI cases during Jan/01/2014 to Dec/31/2018 in VGHTC. We included women who received ART due to endometriosis(n = 208). Exclusion criteria including patients >40 years-old, simulation day < 5 days, severe male factor, uterine factor (including adenomyosis) and immunological factors. Patients whose embryos were not completely transferred back or who received embryo transfer from different OPU cycles are excluded. We followed up these patients till 2020/6. The primary outcome is cumulative LBR

Participants/materials, setting, methods

For first analysis, we divided 208 cases to patients with endometrioma during IVF/ICSI(n = 89), and patients only diagnosed of endometriosis (n = 119). Second analysis on the effect of cystectomy of endometrioma on IVF/ICSI outcomes. Patients with endometrioma (n = 89) during IVF/ICSI were further divided to patients with primary endometrioma (n = 70) and patients with recurrent endometrioma (n = 19, ever received cystectomy for endometrioma). Another group is patients without endometrioma during IVF/ICSI, but ever received cystectomy before (n = 40)

Main results and the role of chance

For the first analysis, age, BMI and AMH were comparable in endometrioma (n = 89) and endometriosis group(n = 119). The usage gonadotropin dose was significantly higher in the endometrioma group (FSH 3619IU vs 3471IU, p = 0.001. LH 1224 IU vs 941 IU, p = 0.009). The Blastocyst formation rate is lower in the endometrioma group (49.4% vs. 57.7% p = 0.005). The OPU number, LBR and cumulative LBR were comparable in both groups (10.3 vs 12.4 p = 0.131, 33.3% vs 37%, p = 0.687, 49.4% vs 60.5%, endometrioma vs endometriosis). For the second analysis, when comparing cystectomy before IVF/ICSI group with primary endometrioma group, cystectomy group were younger (32.8 vs 34.8 p = 0.006). AMH level were comparable. The BC formation rate was significantly higher in the cystectomy group (61.5% vs 50.4% 0= 0.007). The LBR and cumulative LBR were comparable in both groups (43.5% vs 28.1%, 60% vs 48% in cystectomy vs primary endometrioma group). As for the recurrent endometrioma group, the age and AMH level were comparable with cystectomy group, but the usage gonadotropin dose was significantly higher than other two groups. The BC formation rate was also lower than cystectomy group (47.8% vs 61.5% p = 0.042). The LBR and cumulative LBR were comparable with other two groups (55.6%, 57.9%).

Limitations, reasons for caution

This is a retrospective study, and the sample size is limit. We did not analysis the size of endometrioma nor the unilateral or bilateral endometrioma.

Wider implications of the findings: Cystectomy for endometrioma must be carefully selected since it did not alter IVF/ICSI outcome only if the ovarian reserve is not affected. Recurrent endometriomas do not have a worse impact on IVF/ICSI outcome than primary endometrioma. If there is recurrent endometrioma, IVF/ICSI may be the first priority.

Trial registration number

Not applicable

Sacituzumab govitecan, a Trop-2-directed antibody-drug conjugate, for patients with epithelial cancer: final safety and efficacy results from the phase I/II IMMU-132-01 basket trial

BACKGROUND

Sacituzumab govitecan (SG), a trophoblast cell surface antigen-2 (Trop-2)-directed antibody-drug conjugate, has demonstrated antitumor efficacy and acceptable tolerability in a phase I/II multicenter trial (NCT01631552) in patients with advanced epithelial cancers. This report summarizes the safety data from the overall safety population (OSP) and efficacy data, including additional disease cohorts not published previously.

PATIENTS AND METHODS

Patients with refractory metastatic epithelial cancers received intravenous SG (8, 10, 12, or 18 mg/kg) on days 1 and 8 of 21-day cycles until disease progression or unacceptable toxicity. Endpoints for the OSP included safety and pharmacokinetic parameters with investigator-evaluated objective response rate (ORR per RECIST 1.1), duration of response, clinical benefit rate, progression-free survival, and overall survival evaluated for cohorts (n > 10 patients) of small-cell lung, colorectal, esophageal, endometrial, pancreatic ductal adenocarcinoma, and castrate-resistant prostate cancer.

RESULTS

In the OSP (n = 495, median age 61 years, 68% female; UGT1A1∗28 homozygous, n = 46; 9.3%), 41 (8.3%) permanently discontinued treatment due to adverse events (AEs). Most common treatment-related AEs were nausea (62.6%), diarrhea (56.2%), fatigue (48.3%), alopecia (40.4%), and neutropenia (57.8%). Most common treatment-related serious AEs (n = 75; 15.2%) were febrile neutropenia (4.0%) and diarrhea (2.8%). Grade ≥3 neutropenia and febrile neutropenia occurred in 42.4% and 5.3% of patients, respectively. Neutropenia (all grades) was numerically more frequent in UGT1A1∗28 homozygotes (28/46; 60.9%) than heterozygotes (69/180; 38.3%) or UGT1A1∗1 wild type (59/177; 33.3%). There was one treatment-related death due to an AE of aspiration pneumonia. Partial responses were seen in endometrial cancer (4/18, 22.2% ORR) and small-cell lung cancer (11/62, 17.7% ORR), and one castrate-resistant prostate cancer patient had a complete response (n = 1/11; 9.1% ORR).

CONCLUSIONS

SG demonstrated a toxicity profile consistent with previous published reports. Efficacy was seen in several cancer cohorts, which validates Trop-2 as a broad target in solid tumors.

The extracellular lactate-to-pyruvate ratio modulates the sensitivity to oxidative stress-induced apoptosis via the cytosolic NADH/NAD+ redox state

The advantages of the Warburg effect on tumor growth and progression are well recognized. However, the relevance of the Warburg effect for the inherent resistance to apoptosis of cancer cells has received much less attention. Here, we show here that the Warburg effect modulates the extracellular lactate-to-pyruvate ratio, which profoundly regulates the sensitivity towards apoptosis induced by oxidative stress in several cell lines. To induce oxidative stress, we used the rapid apoptosis inducer Raptinal. We observed that medium conditioned by HepG2 cells has a high lactate-to-pyruvate ratio and confers resistance to Raptinal-induced apoptosis. In addition, imposing a high extracellular lactate-to-pyruvate ratio in media reduces the cytosolic NADH/NAD⁺ redox state and protects against Raptinal-induced apoptosis. Conversely, a low extracellular lactate-to-pyruvate ratio oxidizes the cytosolic NADH/NAD⁺ redox state and sensitizes HepG2 cells to oxidative stress-induced apoptosis. Mechanistically, a high extracellular lactate-to-pyruvate ratio decreases the activation of JNK and Bax under oxidative stress, thereby inhibiting the intrinsic apoptotic pathway. Our observations demonstrate that the Warburg effect of cancer cells generates an anti-apoptotic extracellular environment by elevating the extracellular lactate-to-pyruvate ratio which desensitizes cancer cells towards apoptotic insults. Consequently, our study suggests that the Warburg effect can be targeted to reverse the lactate-to-pyruvate ratios in the tumor microenvironment and thereby re-sensitize cancer cells to oxidative stress-inducing therapies.

Overexpression of the constitutive androstane receptor and shaken 3D-culturing increase biotransformation and oxidative phosphorylation and sensitivity to mitochondrial amiodarone toxicity of HepaRG cells

The liver cell line HepaRG is one of the preferred sources of human hepatocytes for in vitro applications. However, mitochondrial energy metabolism is relatively low, which affects hepatic functionality and sensitivity to hepatotoxins. Culturing in a bioartificial liver (BAL) system with high oxygen, medium perfusion, low substrate stiffness, and 3D conformation increases HepaRG functionality and mitochondrial activity compared to conventional monolayer culturing. In addition, drug metabolism has been improved by overexpression of the constitutive androstane receptor (CAR), a regulator of drug and energy metabolism in the new HepaRG-CAR line. Here, we investigated the effect of BAL culturing on the HepaRG-CAR line by applying a simple and downscaled BAL culture procedure based on shaking 3D cultures, named Bal-in-a-dish (BALIAD). We compared monolayer and BALIAD cultures of HepaRG and HepaRG-CAR cells. CAR overexpression and BALIAD culturing synergistically or additively increased transcript levels of CAR and three of the seven tested CAR target genes in biotransformation. Additionally, Cytochrome P450 3A4 activity was 35-fold increased. The mitochondrial energy metabolism was enhanced; lactate production and glucose consumption switched into lactate elimination and glucose production. BALIAD culturing alone reduced glycogen content and increased oxygen consumption and mitochondrial content. Both CAR overexpression and BALIAD culturing decreased mitochondrial superoxide levels. HepaRG-CAR BALIADs were most sensitive to mitochondrial toxicity induced by the hepatotoxin amiodarone, as indicated by oxygen consumption and mitochondrial superoxide accumulation. These data show that BALIAD culturing of HepaRG-CAR cells induces high mitochondrial energy metabolism and xenobiotic metabolism, increasing its potential for drug toxicity studies.

Abstract ES11-2: Neoadjuvant Systemic Treatment (NST): Tailoring Response by Sub-type

Achieving a pathologic complete response (pCR) after neoadjuvant systemic treatment (NST) is clearly associated with improved survival in breast cancer patients, especially with HER2 and triple negative subtypes. In HER2-positive breast cancer patients, the neoadjuvant platform has allowed for the unprecedented accelerated approval for pertuzumab based on improved pCR rates. The KATHERINE trial, in patients who did not achieve pCR following standard trastuzumab/pertuzumab/chemotherapy, demonstrated for the first time that switching to trastuzumab-emtansine (TDM1) led to significant benefit, creating an interesting research paradigm for these high-risk patients with residual disease. For patients with residual disease, the CREATE-X trial demonstrated survival improvement with capecitabine, especially in patients with triple negative disease. New promising agents in the metastatic setting that are being incorporated into NST include immune-check-point inhibitors and cyclin-dependent kinase inhibitors. Evolving technologies like next generation sequencing and gene expression profiles have improved our knowledge regarding the biology of residual disease, and the mechanisms behind treatment resistance, and potentially, metastases. NST allows for testing of new promising treatment regimens - both escalation and de-escalation - depending on sub-types, before surgery. The management and strategies post-NST and the management of residual disease will be discussed.

Citation Format: JC Chang. Neoadjuvant Systemic Treatment (NST): Tailoring Response by Sub-type [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr ES11-2.

A combinatorial biomarker predicts pathologic complete response to neoadjuvant lapatinib and trastuzumab without chemotherapy in patients with HER2+ breast cancer

BACKGROUND

HER2-positive (+) breast cancers, defined by HER2 overexpression and/or amplification, are often addicted to HER2 to maintain their malignant phenotype. Yet, some HER2+ tumors do not benefit from anti-HER2 therapy. We hypothesize that HER2 amplification levels and PI3K pathway activation are key determinants of response to HER2-targeted treatments without chemotherapy.

PATIENTS AND METHODS

Baseline HER2+ tumors from patients treated with neoadjuvant lapatinib plus trastuzumab [with endocrine therapy for estrogen receptor (ER)+ tumors] in TBCRC006 (NCT00548184) were evaluated in a central laboratory for HER2 amplification by fluorescence in situ hybridization (FISH) (n = 56). HER2 copy number (CN) and FISH ratios, and PI3K pathway status, defined by PIK3CA mutations or PTEN levels by immunohistochemistry were available for 41 tumors. Results were correlated with pathologic complete response (pCR; no residual invasive tumor in breast).

RESULTS

Thirteen of the 56 patients (23%) achieved pCR. None of the 11 patients with HER2 ratio <4 and/or CN <10 achieved pCR, whereas 13/45 patients (29%) with HER2 ratio ≥4 and/or CN ≥10 attained pCR (P = 0.0513). Of the 18 patients with tumors expressing high PTEN or wild-type (WT) PIK3CA (intact PI3K pathway), 7 (39%) achieved pCR, compared with 1/23 (4%) with PI3K pathway alterations (P = 0.0133). Seven of the 16 patients (44%) with HER2 ratio ≥4 and intact PI3K pathway achieved pCR, whereas only 1/25 (4%) patients not meeting these criteria achieved pCR (P = 0.0031).

CONCLUSIONS

Our findings suggest that there is a clinical subtype in breast cancer with high HER2 amplification and intact PI3K pathway that is especially sensitive to HER2-targeted therapies without chemotherapy. A combination of HER2 FISH ratio and PI3K pathway status warrants validation to identify patients who may be treated with HER2-targeted therapy without chemotherapy.

Abstract OT3-08-01: A phase Ib/II clinical trial investigating the efficacy of nitric oxide deprivation and docetaxel in triple negative breast cancer

Triple negative breast cancer (TNBC) is an aggressive disease that currently lacks an efficacious form of therapy. Although chemotherapy is the current standard of care for metastatic TNBC, the 5-year prognosis remains grim with a high rate of disease recurrence. Cancer relapse is thought to be initiated by chemotherapy-resistant breast cancer stem cells (BCSCs). These BCSCs give rise to a diverse clonal population that results in a heterogeneous cancer, which complicates targeted therapeutic strategies. Our previous studies revealed that BCSCs utilize inducible nitric oxide synthase (iNOS)-derived nitric oxide to promote their proliferation, migration, and self-renewal capacity. In an effort to target the BCSC population, we found that iNOS inhibition with NG-monomethyl-L-arginine (L-NMMA) sensitized BCSCs to docetaxel in vivo in TNBC xenograft models, leading to decreased BCSC viability and tumor burden. These findings suggest that BCSC resist conventional therapy in a nitric oxide-dependent manner and that combination of L-NMMA with docetaxel will effectively target BCSCs to prevent further relapse. A phase Ib/II clinical trial was conducted to determine the maximum tolerated dose, recommended phase 2 dose (R2PD), dose-limiting toxicities (DLTs), and efficacy of the L-NMMA and docetaxel combination in TNBC patients with chemotherapy-refractory locally advanced or metastatic disease. For the phase Ib portion of the study, a standard Bayesian continual reassessment method is being used to investigate 7 dose levels of L-NMMA (5, 7.5, 10, 12.5, 15, 17.5, and 20 mg/kg) and two dose levels of docetaxel (75 and 100 mg/m2). Sixteen patients have been recruited to date, and based on current pharmacokinetics, pharmacodynamics, and safety data, the RP2D is expected to be docetaxel 100 mg/m2 (Day 1) and L-NMMA 20 mg/kg (Days 1-5) every 3 weeks. Two and three patients received 15 mg/kg L-NMMA + 75 mg/m2 docetaxel and 17.5 mg/kg L-NMMA + 100 mg/m2 docetaxel, respectively. Of these 5 patients, one partial responder completed 8 cycles before discontinuing treatment due to taxane-associated neuropathy. Among the five patients treated at the RP2D, only one taxane-associated DLT occurred. The overall response rate for patients treated at the higher doses was 22.2%. Early results of the phase Ib/II trial indicate the safety, tolerability, and promising activity of the first-in-class pan-NOS inhibitor L-NMMA in combination with chemotherapy in the treatment of chemotherapy-refractory TNBC.

Citation Format: Chung AW, Ensor JE, Darcourt J, Belcheva A, Patel T, Chang JC, Niravath PA. A phase Ib/II clinical trial investigating the efficacy of nitric oxide deprivation and docetaxel in triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT3-08-01.

Abstract P4-15-05: Biomarkers of response to neoadjuvant endocrine therapy with anastrozole (Ana) alone or in combination with fulvestrant (Ful) in ER-positive (ER+) HER2-negative (HER2-) breast cancer (PACT01 trial)

Background: In recent years, several clinical trials showed that fulvestrant (Ful), alone or in combination with an aromatase inhibitor (AI), is more effective than an AI alone. PACT01 is a randomized neoadjuvant trial of Anastrazole (Ana) alone or in combination with Ful in ER+/HER2- breast cancer.

Methods: Patients with newly diagnosed ER+/HER2- breast cancers, 2 cm or larger in size, were randomized to 16 weeks of Ana (1 mg orally every day) alone or in combination with Ful (500mg IM days 1, 15, 29, and every 28 days thereafter) for 16 weeks. Patients then proceeded to surgery. Tumor tissue was collected at baseline, day 28 (D28), and at the time of surgery. Primary endpoint was the reduction of Ki67 in tumor tissue between baseline and D28. Baseline and D28 samples were stained for ER, PR, HER2, and Ki67. ER and PR were scored for intensity and percentage (H-score), HER2 was scored for intensity of membrane staining; and Ki67 was scored as percentage. Data were summarized descriptively. Changes in biomarkers from baseline to D28 were calculated and compared by Wilcoxon signed rank test.

Results: PACT01 trial enrolled 72 patients. Three of them did not start treatment. Baseline samples were collected from the remaining 69 patients, and D28 samples from 60 patients (5 refused, 2 withdrew, 1 lost to follow up, 1 unknown). Samples from 18 patients had no tumor (5 at baseline, 9 at D28, 4 at both). Of the 42 patients with paired samples, 20 received Ana and 22 received Ana+Ful. All cases except one were centrally confirmed to be ER+, and all were HER2-. Table 1 summarizes median expression of Ki67, ER, and PR. Both treatment regimens led to a significant reduction in Ki67 between baseline and D28. However, Ana+Ful did not reduce Ki67 more effectively than Ana alone. Ki67 was reduced to &lt;10% in 60% of the Ana arm and 68% of the Ana+Ful, which was not statistically significant.PR was similarly reduced in both treatment arms. ER was significantly reduced at D28 in the Ana+Ful arm (p=0.0004) but not in the Ana alone arm. Safety profile of both treatment arms was consistent with package insert and published studies.

Median expression of Ki67, ER and PR in Anastrazole and Anastrazole + Fulvestrant Arms at Baseline and Day 28ARMTimepointNKi67 (%)ER H-scorePR H-scoreAnaBaseline2024.8182.5100.3 Day 28205.6*170.025.0Ana + FluBaseline2225.6198.120.5 Day 28225.1*117.50.0* p=0.0004. Other comparisons were not stastistically significant

Conclusions:In this small neoadjuvant trial, the addition of Ful to Ana did not increase Ki67 suppression at D28. This may be due to untreated primary tumors being exquisitely sensitive to Ana and that fulvestrant may not add to it. It is also possible that the effect of Ful may be noted later in the course of treatment. Further biomarker data on tissue collected at the end of treatment will be presented at the meeting.

Citation Format: Dhamne S, Nagi C, Wang T, Pavlick AC, Reusser B, Schiff R, Julie N, Niravath P, Silberfein EJ, Sedgwick EL, Sepulveda KA, Gutierrez C, Hilsenbeck SG, Chang JC, Osborne CK, Rimawi MF. Biomarkers of response to neoadjuvant endocrine therapy with anastrozole (Ana) alone or in combination with fulvestrant (Ful) in ER-positive (ER+) HER2-negative (HER2-) breast cancer (PACT01 trial) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-15-05.

The 2018 rift eruption and summit collapse of Kīlauea Volcano

In 2018, Kīlauea Volcano experienced its largest lower East Rift Zone (LERZ) eruption and caldera collapse in at least 200 years. After collapse of the Pu'u 'Ō'ō vent on 30 April, magma propagated downrift. Eruptive fissures opened in the LERZ on 3 May, eventually extending ~6.8 kilometers. A 4 May earthquake [moment magnitude (M _w) 6.9] produced ~5 meters of fault slip. Lava erupted at rates exceeding 100 cubic meters per second, eventually covering 35.5 square kilometers. The summit magma system partially drained, producing minor explosions and near-daily collapses releasing energy equivalent to M _w 4.7 to 5.4 earthquakes. Activity declined rapidly on 4 August. Summit collapse and lava flow volume estimates are roughly equivalent-about 0.8 cubic kilometers. Careful historical observation and monitoring of Kīlauea enabled successful forecasting of hazardous events.

Child-onset systemic lupus erythematosus is associated with a higher incidence of myopericardial manifestations compared to adult-onset disease

OBJECTIVES

There are no population-based estimates of the incidence or risk factors for acute cardiac manifestations in children with systemic lupus erythematosus (SLE) to guide screening and diagnostic imaging practices. We estimated the incidence and prevalence of acute cardiac manifestations of child-onset SLE compared to adult-onset SLE and identified factors associated with cardiac diagnoses.

METHODS

We identified children (5-17 years) and adults (18-64 years) with incident SLE (≥3 International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9 CM) code 710.0, > 30 days apart) using Clinformatics® DataMart (OptumInsight, Eden Prairie, MN) deidentified United States administrative claims (2000-2013). We calculated incidence and prevalence of three outcomes: ≥ 1 diagnosis code for (1) pericarditis and/or myocarditis, (2) endocarditis, or (3) valvular insufficiency. Negative binomial regression was used to identify characteristics associated with cardiac diagnoses in children and determine whether SLE onset in childhood vs adulthood was independently associated with cardiac involvement.

RESULTS

There were 297 children and 6927 adults with new-onset SLE. A total of 17.8% of children had ICD-9 CM codes for acute cardiac diagnoses, the incidence of which were highest in the first year after SLE diagnosis (12.2 per 100 person-years). African American race (incidence rate ratio (IRR) 6.6, 95% confidence interval (CI) (2.9, 15.0), p < 0.01) and nephritis (IRR 7.0, 95% CI (2.6, 18.6), p < 0.01) were associated with acute cardiac diagnoses in children. Child-onset disease was independently associated with a 4.4-fold higher rate of pericarditis or myocarditis compared to adult-onset SLE after adjustment for other disease and demographic characteristics (95% CI (2.4, 8.0), p < 0.01).

CONCLUSION

This study establishes baseline estimates of the incidence and prevalence of pericarditis and myocarditis in child-onset SLE, which is substantially higher than that of adult-onset SLE. Prospective echocardiographic evaluations are needed to validate incidence measures and characterize the natural history of acute cardiac manifestations in child-onset SLE, as well as identify risk factors for poor cardiac outcomes to inform screening and management.

Evaluation of the reliability and validity of the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) in paediatric cutaneous lupus among paediatric dermatologists and rheumatologists

BACKGROUND

The Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) is a reliable outcome measure for cutaneous lupus erythematosus (CLE) in adults used in clinical trials. However, it has not been validated in children, limiting clinical trials for paediatric CLE.

OBJECTIVES

This study aimed to validate the CLASI in paediatrics.

METHODS

Eleven paediatric patients with CLE, six dermatologists and six rheumatologists participated. The physicians were trained to use the CLASI and Physician's Global Assessment (PGA), and individually rated all patients using both tools. Each physician reassessed two randomly selected patients. Within each physician group, the intraclass correlation coefficient (ICC) was calculated to assess the reliability of each measure.

RESULTS

CLASI activity scores demonstrated excellent inter- and intrarater reliability (ICC > 0·90), while the PGA activity scores had good inter-rater reliability (ICC 0·73-0·77) among both specialties. PGA activity scores showed excellent (ICC 0·89) and good intrarater reliability (ICC 0·76) for dermatologists and rheumatologists, respectively. Limitations of this study include the small sample size of patients and potential recall bias during the physician rerating session.

CONCLUSIONS

CLASI activity measurement showed excellent inter- and intrarater reliability in paediatric CLE and superiority over the PGA. These results demonstrate that the CLASI is a reliable and valid outcome instrument for paediatric CLE.

Oxygen drives hepatocyte differentiation and phenotype stability in liver cell lines

The in vitro generation of terminally differentiated hepatocytes is an unmet need. We investigated the contribution of oxygen concentration to differentiation in human liver cell lines HepaRG and C3A. HepaRG cells were cultured under hypoxia (5%O2), normoxia (21%O2) or hyperoxia (40%O2). Cultures were analysed for hepatic functions, gene transcript levels, and protein expression of albumin, hepatic transcription factor CEBPα, hepatic progenitor marker SOX9, and hypoxia inducible factor (HIF)1α. C3A cells were analysed after exposure to normoxia or hyperoxia. In hyperoxic HepaRG cultures, urea cycle activity, bile acid synthesis, CytochromeP450 3A4 (CYP3A4) activity and ammonia elimination were 165-266% increased. These effects were reproduced in C3A cells. Whole transcriptome analysis of HepaRG cells revealed that 240 (of 23.223) probes were differentially expressed under hyperoxia, with an overrepresentation of genes involved in hepatic differentiation, metabolism and extracellular signalling. Under hypoxia, CYP3A4 activity and ammonia elimination were inhibited almost completely and 5/5 tested hepatic genes and 2/3 tested hepatic transcription factor genes were downregulated. Protein expression of SOX9 and HIF1α was strongly positive in hypoxic cultures, variable in normoxic cultures and predominantly negative in hyperoxic cultures. Conversely, albumin and CEBPα expression were highest in hyperoxic cultures. HepaRG cells that were serially passaged under hypoxia maintained their capacity to differentiate under normoxia, in contrast to cells passaged under normoxia. Hyperoxia increases hepatocyte differentiation in HepaRG and C3A cells. In contrast, hypoxia maintains stem cell characteristics and inhibits hepatic differentiation of HepaRG cells, possibly through the activity of HIF1α.

Use of echocardiography at diagnosis and detection of acute cardiac disease in youth with systemic lupus erythematosus

Objectives There are no guidelines on the use of echocardiography to detect cardiac manifestations of childhood-onset systemic lupus erythematosus (SLE). We quantify the prevalence of acute cardiac disease in youth with SLE, describe echocardiogram utilization at SLE diagnosis, and compare regional echocardiogram use with incident cardiac diagnoses. Methods Using the Clinformatics® DataMart (OptumInsight, Eden Prairie, MN) de-identified United States administrative database from 2000 to 2013, we identified youth ages 5-24 years with new-onset SLE (≥3 ICD-9 SLE codes 710.0, > 30 days apart) and determined the prevalence of diagnostic codes for pericardial disease, myocarditis, endocarditis, and valvular insufficiency. Multiple logistic regression was used to identify factors associated with echocardiography during the baseline period, up to one year before or six months after SLE diagnosis. We calculated a regional echocardiogram utilization index, which is the ratio of observed use over the mean predicted probability based on all available baseline characteristics. Spearman's rank correlation coefficient was used to evaluate the association between regional echocardiogram utilization indices and percentage of imaged youth diagnosed with their first cardiac manifestation following echocardiography. Results Among 699 youth with new-onset SLE, 18% had ≥ 1 diagnosis code for acute cardiac disease, of which valvular insufficiency and pericarditis were most common. Twenty-five percent of all youth underwent echocardiogram during the baseline period. Regional echocardiogram use was positively correlated with the percentage of imaged youth found to have cardiac disease (ρ = 0.71, p = 0.05). There was up to a five-fold difference in adjusted odds of baseline echocardiography between low- and high-utilizing regions (OR = 0.19, p = 0.007). Conclusion Nearly one-fifth of youth with new-onset SLE have acute cardiac manifestations; however, use of echocardiograms at SLE diagnosis is highly variable. There may be incremental diagnostic value to early use of echocardiography, but prospective studies are needed to determine whether greater use of echocardiograms modifies outcomes.

Training reproductive health providers to talk about intimate partner violence and reproductive coercion: an exploratory study

To explore the effect of provider communication-skills training on frequency of intimate partner violence (IPV) and reproductive coercion (RC) assessment, four family planning clinics were randomized to IPV/RC communication-skills building workshop or standard knowledge-based IPV/RC training and compared to historical controls from the same clinics (before any training). Female patients aged 16-29 completed after-visit surveys. Primary outcomes included provider discussion about IPV/RC, receipt of safety card with IPV/RC resources and patient disclosure of IPV/RC. Chi-square tests were used to compare groups that received training and historical controls. Participants (training: n = 103; historical control: n = 576) were predominantly white with mean age of 22. More patients reported discussion about healthy relationships in both training groups (78-90%) compared to historical controls (49-52%, P < 0.001 for both). Discussion on birth control sabotage and pregnancy coercion was infrequent with patient-participants in both groups (6-17 and 4-13%, respectively). More patients in the clinics that received training reported receiving a safety card (72-84%) as compared to historical controls (9%, P < 0.001 for both). Overall, in this exploratory study, both communication-skills and standard training improved frequency of IPV communication when compared to historical controls but with few differences when compared to each other.

Abstract P6-07-10: The ERβ4 variant induce transformation of the normal breast mammary epithelial cell line MCF-10A; the ERβ variants ERβ2, ERβ4 and ERβ5 increase aggressiveness of TNBC by regulation of hypoxic signaling

Triple negative breast cancer (TNBC) still remains a challenge to treat in the clinic due to a lack of good targets for treatment. Although TNBC lacks expression of ERα, the expression of ERβ and its variants are detected quite frequently in this cancer type and can represent an avenue for treatment. We show that the variants of ERβ, namely ERβ1, ERβ2, ERβ4, and ERβ5, regulate aggressiveness of TNBC by regulating hypoxic signaling. RNA-seq of patient derived xenografts (PDX) from TNBC show expression of ERβ4 and ERβ5 variants in more than half of the samples. Furthermore, expression of ERβ4 in the immortalized, normal mammary epithelial cell line MCF-10A that is resistant to mammosphere formation caused transformation and development of mammospheres. By contrast, ERβ1, ERβ2 or ERβ5 were unable to support mammosphere formation. We have previously shown that all variants except ERβ1 stabilizes HIF-1α but only ERβ4 appear to have the ability to transform normal mammary epithelial cells, pointing towards a unique property of ERβ4. We propose that ERβ variants may be good diagnostic tools and also serve as novel targets for treatment of breast cancer.

Citation Format: Faria M, Karami S, Granados-Principal S, Dey P, Verma A, Choi DS, Elemento O, Bawa-Khalfe1 T, Chang JC, Gustafsson J-A, Strom AM. The ERβ4 variant induce transformation of the normal breast mammary epithelial cell line MCF-10A; the ERβ variants ERβ2, ERβ4 and ERβ5 increase aggressiveness of TNBC by regulation of hypoxic signaling [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-07-10.

Abstract P5-13-03: The use of a behavior-modification clinical solution application to improve breast cancer survivors' accountability and health outcomes

Background: Studies have demonstrated that obesity increases the risk of breast cancer recurrence and death in survivors but only 34% of breast cancer survivors engage in the recommended level of physical activity. This low percentage is related to a lack of accountability and motivation. We hypothesize that using a mobile application (app) incorporating the concept of cognitive-behavioral therapy and dietary and physical activity recommendations will improve breast cancer survivors' accountability and help them reach their personalized health goals; specifically with diet and exercise. Methods: We have created an app, METHODIST HOSPITAL CANCER HEALTH APPLICATION (MOCHA) for the purpose of patient self-reinforcement through the daily accounting of activity and nutrition as well as group feedback and direct interaction with clinical dietician. To test the MOCHA app's feasibility, we enrolled 33 breast cancer survivors with a body mass index (BMI) over 25 who were at least 6 months post active treatment (surgery, chemotherapy, or radiation) for a 4 week feasibility trial. During these 4 weeks, the users used the app to track wellness (mood, sleep or pain), diet (calorie intake) and exercise (walking or steps). Our primary objective was to demonstrate adherence, defined as the number of days recorded on MOCHA during week 2 and 3 of the 4 week study period (14 days). A registered dietitian assigned personalized goals for each user and monitored their usage of the app and followed the progress of their goals. Additionally, the dietitian sent daily push notifications to encourage the user to stay on track. Results: Our results suggests a correlation between utilization of the app and achievement of the goals of weight loss and increased motivation to exercise. The average number of daily uses of the app was approximately 3.76 (0-12) and 50% of enrolled users lost average of 2.14 lbs (0-6lbs) weight during this short 4 week study; preliminary correlation analysis suggest a correlation coefficient of -0.42 between these two variables. This is noteworthy as traditionally we would expect weight increase in this group of users. Our secondary objective was to determine MOCHA's usability using System Usability Scale (SUS) scale. Our average score on the SUS scale is 77%, which is above average. Lastly, users have stated that access to the dietitian in the app improves their food choices and accountability. Conclusion: This study provides essential data that emphasizes the importance of using technology to improve patients' goal adherence by providing real-time feedback and accountability with their healthcare team. Most health mobile apps focus on data acquisition but without the engagement of the health care team, this aspect differentiates MOCHA from the other apps. Our future directions will focus on using our MOCHA app in breast cancer survivors in a long term behavior modification study.

Citation Format: Stubbins RE, Cheng TH, Yu X, Puppala M, Chen S, Valdivia Y Alvarado M, Niravath PA, Chang JC, Wong ST, Patel TA. The use of a behavior-modification clinical solution application to improve breast cancer survivors' accountability and health outcomes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-13-03.

The Emerging Role of Soluble Adenylyl Cyclase in Primary Biliary Cholangitis

BACKGROUND

Primary biliary cholangitis (PBC; previously referred to as primary biliary cirrhosis) is a chronic fibrosing cholangiopathy with the signature of an autoimmune disease and features of intrahepatic cholestasis. Immunosuppressing treatments are largely unsuccessful. Responsiveness to ursodeoxycholic acid and reduced expression of anion exchanger 2 (AE2) on canalicular membranes and small bile ducts underline the importance of bicarbonate transportation in its disease mechanism. Soluble adenylyl cyclase (sAC; ADCY10) is an evolutionarily conserved bicarbonate sensor that regulates apoptosis, barrier function and TNF signaling. Key Messages: The biliary epithelium defends against the toxic bile by bicarbonate secretion and by maintaining a tight barrier. Passive diffusion of weak acid conjugates (e.g. bile salts and other toxins) across plasma membrane is pH-dependent. Reduced AE2 expression results in both reduced bicarbonate secretion and accumulation of bicarbonate in the cells. Increased intracellular bicarbonate leads to increased sAC activity, which regulates bile salt-induced apoptosis. Reduced bicarbonate secretion causes more bile salts to enter cells, which further increase sAC activity by releasing intracellular Ca2+ store. In vitro studies demonstrate that inhibition of sAC not only corrects sensitization to bile salt-induced apoptosis as a result of AE2 down-regulation but also prevents bile salt-induced apoptosis altogether. Targeting sAC is also likely to slow down disease progression by strengthening the barrier function of biliary epithelia and by reducing oxidative stress as a result of chronic inflammation.

CONCLUSIONS

sAC is a potential therapeutic target for PBC. More in vitro and in vivo studies are needed to understand how sAC regulates bile salt-induced apoptosis and to establish its therapeutic value in PBC and other cholestatic cholangiopathies.

Abstract ES6-1: ES6-1 Assessment of residual disease and treatment implications post neoadjuvant therapy

Breast cancer is a highly heterogeneous disease with various molecular subtypes that differ in regard to treatment approach as well as unresolved treatment issues.

In women with HER2-amplified breast tumors, standard neoadjuvant therapy consisting of dual HER2 blockade with trastuzumab/pertuzumab plus chemotherapy can induce a high pathologic complete response (pCR) rate (60%), which translates into better overall survival (&gt;90% at 3 years). A critical unresolved issue in the neoadjuvant treatment of HER2-amplified tumors is minimizing toxicity in select patients. Selection of non-cardiogenic regimens and chemotherapy-free or lighter chemotherapy regimens should be the focus for women whose disease is highly addicted to the HER2 pathway. New research directions are also exploring ways to minimize the extent of local surgery in the breast and axilla.

Approximately 30% of patients with triple-negative breast cancer (TNBC) achieve pCR after neoadjuvant chemotherapy. While these patients tend to have a favorable prognosis, those with residual disease (RD) at the time of surgical resection may expect significantly worse outcomes and, at present, do not have targeted therapeutic options. Molecular analysis of tumor tissue from such patients may be used to identify the genetic alterations responsible for disease recurrence and to help individualize treatment with available agents. Transcriptome and sequencing analyses have identified important pathways and aberrations in the majority of residual tumors. Targeting these molecular abnormalities in conjunction with the tumor immune microenvironment may represent an effective therapeutic avenue to improve the outcomes of TNBC patients who have RD after standard neoadjuvant therapy. Adaptive clinical trials investigating neoadjuvant treatments directed against key pathways active in residual tumors are underway.

Citation Format: Chang JC. ES6-1 Assessment of residual disease and treatment implications post neoadjuvant therapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr ES6-1.

Abstract P6-14-02: An anti-PD1 antibody-based therapy results in dramatic reduction of TNBC PDX tumors in humanized mice models

Recently, the field of cancer immunotherapy has seen a rapid growth based on a better understanding of the complex interplay between the tumor and the immune system. Although for long time breast cancer has been considered non-immunogenic and patients have seen limited options to immunotherapies, new strategies have changed this paradigm. In the present study, we aimed to test the in vivo activity of a human anti-PD1 antibody against the TNBC tumor line MC1. One of the main limitations of performing laboratory-based in vivo studies resides in the availability of the appropriate animal models. To circumvent these obstacles, we used patient-derived breast cancer tumor lines xenografts (PDX) from our existing collection previously established in immuno-compromised SCID/beige mice. Low-passage fresh xenograft tumor fragments of the TNBC tumor lines MC1 and HM#2147 were transplanted into the cleared fat pad of recipient non-humanized (non-hNSG) and humanized NSG (hNSG) mice. Humanized mice were obtained by i.v. injecting 3-4 weeks old NSG mice with CD34+ hematopoietic stem cells (HSC) following whole body radiation. Flow cytometry and immuno-histochemistry analyses of hNSG blood, spleen and bone marrow showed the presence of human CD45+ (15.1% ± 10.3; 61.5% ± 19.1; 71.9% ± 17.9; respectively), CD20+, CD3+, CD8+, CD68+, and CD33+ cells. BC tumor engraftment was then evaluated by comparing the growth of the MC1 tumor line in non- and hNSG mice, showing a slower growth in the corresponding humanized mice. Importantly, the presence of hCD45+ cells was readily detectable in all the hNSG-derived tumors, localizing both toward the periphery of the tumors and inside them. Analysis of hCD45+ subpopulation cells showed also the tumor presence of hCD20+ cells (B cells), hCD8+ T-cells and CD68+ (macrophages) cells. To determine whether BC PDX may have conserved the capability to metastasize to the lung, hNSG mice were engrafted with the tumor line HM#2147. Once the primary tumor reached the maximum volume allowed by humane standards, mice humanization levels, tumor engraftment and lung metastasis were evaluated. Humanized engrafted mice showed same levels of human cells and primary tumor engraftment as those harboring MC1 PDXs. Macroscopically, lungs displayed clear evidence of metastases. IHC assays using Ki67 and CK19 identified the microscopic region corresponding to its localization. Importantly, as described in the primary breast tumor, the presence of hCD45+ was also observed infiltrating the lung metastatic tumor. The efficacy of an anti-PD1 therapy was then evaluated. Levels of tumor PD-L1 were determined by western blot showing high levels of expression. Animals were weekly i.p.-administered either the human anti-PD1 antibody or vehicle. Evaluation of tumor volumes showed a significant reduction in anti-PD1- vs. vehicle-treated animals at day 18 of treatment (i.e. 457.8 mm3 vs. 1074.24 mm3, respectively; P= 0.001). The present study show encouraging results associated with anti-PD1 immunotherapy to treat TNBC tumors. In addition, our results provide evidence supporting the use of humanized mice as key animal model that may allow to overcome some of the technical difficulties associated with the investigation of immune-based therapies.

Citation Format: Rosato RR, Davila-Gonzalez D, Choi DS, Dave B, Chang JC. An anti-PD1 antibody-based therapy results in dramatic reduction of TNBC PDX tumors in humanized mice models [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-14-02.

Abstract P1-02-06: Serial monitoring of circulating tumor DNA in patients with metastatic breast cancer

Background: For patients with MBC, there is currently no evidence that changing therapy on the basis of biomarker results improves outcome. Clinical benefit of treatment is defined as complete response, objective response, or stable disease as determined by RECIST criteria on radiological evaluation. Serial measurements of serum biomarkers such as CA2729 and CTCs have proven unsuccessful in predicting clinical benefit. Circulating tumor DNA(ctDNA) has emerged as a potential biomarker that may predict response to therapy or progression of disease. The present retrospective study was conducted to evaluate the relationship between change in ctDNA with clinical benefit determined by clinical and radiological evaluations of patients with MBC patients.

Methods: We conducted a retrospective, single-institutional study to determine if serial monitoring of ctDNA allele frequency levels predict clinical benefit of a treatment. 55 patients with measurable MBC who had serial monitoring of ctDNA between August 2014 and May 2016 were included. The median age was 55.9 (27–94) years). Clinical outcomes were determined as per standard guidelines. The analysis was performed on all cases that had serial measurements of ctDNA with no change in therapy in between and the repeat blood draw was done within 30 days of repeat radiographic evaluation. The dataset contained 125 observations from 48 unique patients. The relationship between the change in ctDNA and clinical benefit was analyzed using a generalized linear model with a random subject effect to account for the intrapatient dependence occurring from obtaining multiple evaluations from the same patient. A logit link function was used akin to logistic regression and a compound symmetric correlation structure was assumed.

Results: 68.8% of the cases were hormone receptor-positive, 18.8% HER2-positive, and 27.1% TNBC. The treatments received were 58.4% hormonal therapy, 31.2% chemotherapy, 26.4% included anti-HER2 therapy, 2 cases were on targeted therapy, and 1 case was not on any treatment. Three patients had stage 4 disease in complete remission. ctDNA analysis was repeated on average 4 days prior to radiological evaluation. The average time between repeat assessments was 108.5 days. 93% of the patients had a genomic alteration detected at some point during their course of disease. The most common mutations detected were TP53 41.7%, PIK3CA 35.4%, ESR1 18.8%, and ERBB2 amplifications 6.3%. A dichotomized change in ctDNA is a significant predictor of clinical benefit (p &lt; 0.0001). The intrapatient correlation is estimated to be 0.273 for the transformed variable. The model yields a predicted probability of clinical benefit of 26.9% when the increase in ctDNA is greater than or equal to 0.5 and when the increase in ctDNA is less than 0.5, the a predicted probability of clinical benefit is 78.4%. The concordance of change in ctDNA and change in CA 27-29 was 76.2%.

Conclusions: Serial evaluation of serum ctDNA may be useful to evaluate molecular response to treatment which may correlate with clinical benefit and potentially guide treatment decisions. Early indication that a chosen therapy is not effective may lead to avoidance of overtreatment and initiation of an alternative regimen. Further, prospective studies are needed.

Citation Format: Patel A, Mukherjee A, Hwang D, Ensor J, Patel TA, Chang JC, Rodriguez AA. Serial monitoring of circulating tumor DNA in patients with metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-02-06.

Abstract P3-03-02: Inhibition of NOS promotes ER stress response and augments docetaxel-mediated apoptosis in TNBC

Introduction: Chemoresistance in triple negative breast cancer (TNBC) is related to an activation of a survival response orchestrated by endoplasmic reticulum (ER) stress. We hypothesize that attenuation of nitric oxide (NO) signaling pathway can overcome treatment resistance, preventing relapse, ultimately improving survival of TNBC patients. Here, we aimed to investigate the effects of pharmacological iNOS (inducible nitric oxide synthase) inhibition by L-NMMA on docetaxel-meditated ER stress response and to determine whether the therapeutic NOS inhibition may improve chemotherapy-based response.

Methods: BT-549, SUM-149, MDA-MB-436, and MDA-MD-468 TNBC cell lines were treated with docetaxel (D; 5 nm)/ L-NMMA (L; 4mM)/ amlodipine (A; 5 µm) daily for 48 and 72 hours. Cell death and proliferation were assayed by Annexin V and ATP quantification, respectively. Western Blot (WB) was used to measure ER stress markers. In vivo regimen treatment followed three 2-weekscycles of D (20 mg/kg intraperitoneal [IP] on day 1) and L (200 mg/kg oral gavage on day 2-6); A (10 mg/kg IP on day 2-6) A was administered together with L to counteract the well-known effects of L on blood pressure (hypertension). TNBC Patient derived xenograft (PDX) models #2147, #5998, #3107 and #4664 were transplanted into the mammary fat pad of SCID Beige mice. PDX #2147 received either, single drug (vehicle, L, A, D), double (L+A, D+L, D+A), or triple drug combination (L+A+D). Models #4664, #3107 and #5998 received only vehicle, D or D+ L+A. Mice weight and tumor volumes were recorded twice weekly. D concentration was measured by mass spectrometry.

Results: Studies on SUM-159 cell line showed that, when compared to the docetaxel-treated group, D+L+A increased cell death significantly, as indicated by a rise in annexin V/propidium iodide-positive cells. Increase in cell death by D+L+A was further demonstrated by accumulation of mitochondrial cleaved BAX. The enhanced apoptotic effects of D+L+A in MDA MD 468, BT 549 and MDA MD TNBC cell lines were confirmed by a decrease in ATP levels compared to D alone. WB revealed a survival stress response activated by docetaxel. When it was coupled with NOS inhibition, ER stress response showed higher expression of ATF4 and CHOP, triggering a proapoptotic response by pASK1/JNK pathway and cleaved caspases (CC3 and CC9). PDX #2147 showed that L, A and L+A treatment groups had similar tumor volume growth as the untreated group. However, combination therapy, D+L+A, significantly reduced the tumor volume and increased survival proportions compared with vehicle and docetaxel. Combination therapy also dramatically reduced tumor size on TNBC #4664 and #3107, and significantly improved response on #5998 compared with docetaxel alone. Intratumoral docetaxel concentration was 5.3-fold higher in mice receiving D+L+A than in those receiving docetaxel alone (#5998). In both groups, docetaxel was not detected in the plasma one week after injection.

Conclusion: The present data suggest that iNOS may be a critical target for docetaxel resistance in TNBC. iNOS inhibition enhanced chemotherapy response in TNBC PDX models indicating that addition of iNOS inhibitor may improve prognosis and prevent relapse in TNBC patients who have failed conventional chemotherapy.

Citation Format: Davila-Gonzalez D, Choi DS, Kuhn J, Granados SM, Rosato RR, Dave B, Chang JC. Inhibition of NOS promotes ER stress response and augments docetaxel-mediated apoptosis in TNBC [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-03-02.

Abstract P5-05-01: Physico-biochemical regulation of EMT by microtubule associated protein 7 (MAP7)

Background: We previously reported about 500 cancer stem cell (CSC) specific gene signatures from patient tumor samples. After screening with shRNAs for the 500 genes affecting mammosphere forming ability, we identified microtubule-assoicated protein 7 (MAP7) as one of the top candidate genes, which may serve as a target for breast CSCs. Although MAP7 is a predominant epithelial microtubule binding protein, only limited number of reports suggests that MAP7 may be a regulator of microtubule dynamics during cell division and a cofactor of Kinesin-1 in compartment transport in cells. However, little is known about how MAP7 supports epithelial cancers, especially breast cancer. Previously, we have reported that the mammosphere forming cells exhibit treatment resistance and high metastatic potential, which are intrinsic characters for CSCs displaying epithelial mesenchymal transition (EMT). We hypothesize that MAP7 supports breast cancer progression by promoting CSC self-renewal and survival through regulation of EMT.

Objectives: Here, we aim to show that MAP7 is an essential regulator of breast CSCs and to elucidate mechanism behind EMT regulation by MAP7 in breast CSCs.

Methods and Results: On Oncomine database analysis, MAP7 was up-regulated in most epithelial cancers, when compared to the corresponding normal tissues. Similarly, its expression in breast cancer was 2-fold higher than in the normal breast tissue (p&lt;0.05), but without significant variances in the expression across the breast cancer subtypes. Gene silencing of MAP7 significantly reduced CD44+/CD24- breast CSC populations and mammosphere forming efficiencies of MDA-MB-231, HCC1937, and MDA-MB-468 breast cancer cells. Furthermore, the silencing of MAP7 expression compromised invasive potential of MDA-MB-231 cells by 50% and significantly altered the cell membrane mechanics of MDA-MB-468 cells, as indicated by a high-content image analysis for cell shapes and cell adhesion efficiency. More importantly, delivery of siRNA in vivo inhibited the growth of BCM2147 patient-derived tumor, and limiting dilution assay demonstrated that the tumor initiation potential of BCM2147 can be eliminated by MAP7 silencing. Through confocal microscope analysis of images of fluorescent immunostaining and co-immunoprecipatation assays, MAP7 showed polarized-expressions in spindle-shaped cancer cells and was co-localized with Focal Adhesion Kinase (FAK). Moreover, MAP7 silencing inhibited the phosphorylation of FAK by inactivating p130CAS and JSAP1, the upper stream and the down-stream regulators of FAK.

Conclusion: We have showed the ectopic expression of MAP7 in breast tumors and other epithelial tumors, suggesting MAP7 may be involved in tumorigenesis and critical for the survival of tumor cells. Moreover, our results suggest that MAP7 is a key element for survival and self-renewal of breast CSCs through polarization of cells and activation of FAK, required for the initiation of EMT. To that end, here we report that MAP7 is essential for breast cancer growth by supporting CSC survival and self-renewal.

Citation Format: Choi DS, Dave B, Rosato RR, Chang JC. Physico-biochemical regulation of EMT by microtubule associated protein 7 (MAP7) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-05-01.

Elevated interleukin-8 in bile of patients with primary sclerosing cholangitis

BACKGROUND & AIMS

To better understand the pathogenesis of primary sclerosing cholangitis, anti- and pro-inflammatory factors were studied in bile.

METHODS

Ductal bile of PSC patients (n = 36) and controls (n = 20) was collected by endoscopic retrograde cholangiography. Gallbladder bile was collected at liver transplantation. Bile samples were analysed for cytokines, FGF19 and biliary lipids. Hepatobiliary tissues of PSC and non-PSC patients (n = 8-11 per patient group) were collected at transplantation and were analysed for IL8 and FGF19 mRNA expression and IL8 localization. The effect of IL8 on proliferation of primary human cholangiocytes and expression of pro-fibrotic genes was studied.

RESULTS

In PSC patients, median IL8 in ductal bile was 6.6 ng/ml vs. 0.24 ng/ml in controls. Median IL8 in gallbladder bile was 7.6 ng/ml in PSC vs. 2.2 and 0.3 ng/ml in two control groups. IL8 mRNA in PSC gallbladder was increased and bile ducts stained positive for IL8. In vitro, IL8 induced proliferation of primary human cholangiocytes and increased the expression of pro-fibrotic genes.

CONCLUSION

Elevation of IL8 in bile of PSC patients, collected at different stages of disease, indicates an ongoing inflammatory stimulus that drives IL8 production. This challenges the idea that advanced PSC is a burned-out disease, and calls for reconsideration of anti-inflammatory therapy in PSC.

Effects of prefeeding a prebiotic on diarrhea and colonic cell proliferation in piglets fed lactulose

OBJECTIVES

Severe lactulose malabsorption causes osmotic diarrhea and decreased cecal cell proliferation. We tested the hypothesis that prefeeding with inulin, a prebiotic, would attenuate these effects.

METHODS

Piglets aged 10 days were randomized to 3 feeding groups (n = 6 each group): Control (CON), fed sow-milk replacement formula (SMR; lactose, 60 g/L) for 14 days; a lactulose-challenged group (LAC) that was fed SMR for 7 days and then a formula containing lactose (30 g/L) and lactulose (60 g/L) for 7 days; and a group prefed SMR containing inulin (3 g/L) for 7 days and then fed the lactulose-supplemented formula (INULIN). Groups CON and INULIN were pair-fed to LAC. Then, cecal tissue was collected for histology, determination of crypt cell proliferation index, apoptosis, and Western blot determination of expression of Bax, a pro-apoptotic protein.

RESULTS

The fraction of days when diarrhea was present (mean +/- SD) was greater for LAC (0.87 +/- 0.14; p = .004) than CON (0.28 +/- 0.22; INULIN: 0.52 +/- 0.44; p = .058 vs LAC). Cell proliferation index for the total crypt was less for LAC (0.12 +/- 0.04; p = .016) compared with CON (0.20 +/- 0.04; INULIN: 0.15 +/- 0.04; p = .06 vs LAC). BAX protein expression and apoptosis were similar in the 3 groups.

CONCLUSIONS

We observed trends consistent with the hypothesis that prefeeding inulin attenuates diarrhea and the reduction in cell proliferation caused by lactulose.

Abstract PD3-06: Safety and efficacy of anti-Trop-2 antibody drug conjugate, sacituzumab govitecan (IMMU-132), in heavily pretreated patients with TNBC

Background: Triple-negative breast cancer (TNBC) comprises about 15% of all breast cancer types, and has a particularly aggressive course. Following first-line therapy, the median PFS is &lt;3 months, and OS is &lt;10 months. Therefore, new treatment strategies are needed. Since Trop-2 is expressed in &gt;90% of TNBC, as measured by IHC, we conducted a trial to evaluate the safety and efficacy of a humanized anti-Trop-2 monoclonal antibody conjugated to a high concentration of SN-38, a camptothecin that is a topoisomerase I inhibitor and the active metabolite of the prodrug irinotecan, with 2-3 logs higher potency than the prodrug.

Methods: After establishing the optimal repeated dose in a Phase I trial (ClinicalTrials.gov, NCT01631552) involving many different solid cancer types, an expanded Phase II was undertaken in a number of cancers, including TNBC. Patients received 8 or 10 mg/kg IMMU-132 i.v. on days 1 and 8 of 21-day repeated cycles. Assessments of safety and response by RECIST1.1 were made weekly and bimonthly, respectively. Tumor biopsies (archival, at baseline prior to treatment, and at disease progression) were obtained when safe and feasible.

Results: As of May 10, 2015, 58 patients with TNBC, with a median of 4 prior therapies (range, 1-11), were treated with IMMU-132. Grade 3-4 toxicities included neutropenia (26%), febrile neutropenia (2%), diarrhea (2%), anemia (4%), and fatigue (4%). No patient developed antibodies to SN-38 or the antibody, and no patient discontinued therapy due to toxicity. Tumor responses were defined as ORR (CR+PR) in 31% of 49 evaluated patients, including 2 with CR, and a clinical benefit ratio (CR+PR+SD&gt;6 mo) of 49% (63% with SD&gt;4 mo; 23 patients continuing treatment after 1st assessment). The current median progression-free survival is 7.3 months with 44% maturity in 50 patients treated at the 8 or 10 mg/kg dose level. Overall survival data are still not mature 20 months after enrollment of first patient. Clinical efficacy correlated to biomarker studies, including Trop-2 expression (target of antibody), topoisomerase-1 expression (target of SN-38), and homologous recombinant deficiency (HRD) assay (marker of DNA repair), is being studied. Immunohistochemistry results in archival specimens currently show 97% positivity of Trop-2 among 34 specimens evaluated, with 79% having high intensity (2+/3+) staining.

Conclusions: The Trop-2-targeting IMMU-132, delivering cytotoxic doses of the topoisomerase I inhibitor, SN-38, shows manageable toxicity, and encouraging anti-tumor activity in relapsed/refractory patients with TNBC. This ADC appears to have a high therapeutic index in heavily pretreated patients.

Citation Format: Bardia A, Diamond JR, Mayer IA, Starodub AN, Moroose RL, Isakoff SJ, Ocean AJ, Guarino MJ, Berlin JD, Messersmith WA, Thomas SS, O'Shaughnessy JA, Kalinsky K, Maurer M, Chang JC, Forero A, Traina T, Gucalp A, Wilhelm F, Wegener WA, Maliakal P, Sharkey RM, Goldenberg DM, Vahdat LT. Safety and efficacy of anti-Trop-2 antibody drug conjugate, sacituzumab govitecan (IMMU-132), in heavily pretreated patients with TNBC. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD3-06.

Abstract P6-03-05: Cell-free DNA as molecular tool for monitoring disease progression and response to therapy in breast cancer patients

Background: Identification of cancer-specific genes from breast cancer cells was instrumental in the advancement of targeted breast cancer therapy. However, with genomic heterogeneity within the breast cancer and evolution of cancer over time, genomic sequencing obtained from a single biopsy site may not capture the complete genomic profile. Thus, circulating cell-free DNA (cfDNA), isolated from plasma, is potentially a non-invasive source of identifying cancer-specific genomic alterations and may provide comprehensive genomic data throughout a patient's clinical course as they undergo anti-cancer therapy.

Method: We performed a retrospective chart review of 100 patients with stage 4 or high-risk stage 3 breast cancer who were tested for cfDNA genomic alterations. The most common actionable cancer specific genomic alterations were identified. In 23 patients who also had genomic analysis from tumor DNA (tDNA), an analysis using the Cohen's Kappa statistic was performed to determine the degree of agreement between genomic alterations found in tDNA and cfDNA. The proportion of patients with clinical disease progression between two cohorts determined by change in mutant allele frequency was compared using two-sided Fisher's exact test. Patients who received targeted therapy based on the identified genomic alteration were followed to determine response to therapy.

Results: In cfDNA of 100 breast cancer patients, the most commonly found cancer specific genomic alterations were TP53, PIK3CA, EGFR amplification, and ERBB2 amplification, with incidence rates 27%, 22%, 9%, and 7%, respectively. In tDNA of 23 patients, incidence rates were 65%, 26%, 9%, and 13%. PIK3CA and ERBB2 amplification demonstrated robust agreement between tDNA and cfDNA (Cohen's Kappa= 0.64 and 0.77, respectively). TP53 and EGFR amplification demonstrated poor agreement between tDNA and cfDNA (Cohen's Kappa= 0.18 and 0.33, respectively). There were 22 patients who had baseline and post-therapy mutant allele frequency measurements of TP53 and PIK3CA. Directional change of mutant allele frequency was closely associated with patient's response to therapy (p=0.0017). 8 out of 8 patients (100%) who had progression of disease had increase in mutant allele frequency. 10 out of 14 patients (71%) of patients who responded to therapy had decrease in mutant allele frequency. 6 patients who were found to have ERBB2 amplification were initiated on anti-HER2 cancer therapy. 5 of 6 patients (83%) had clinical response to therapy, while one patient had progression of disease. 3 patients who were found to have EGFR amplification (2 in cfDNA, 1 in tDNA) were initiated on anti-EGFR therapy. 2 of 3 patients (67%) had clinical response to therapy, while one patient had progression of disease.

Conclusion: There is no definite agreement between genomic alterations found in tDNA and those found in cfDNA. Whether this is due to tumor heterogeneity or tumor evolution over time with administration of anti-cancer treatment remains unknown. However, identification of selected cancer specific genomic alterations from cfDNA may be a non-invasive tool to monitor disease progression and response to breast cancer therapy.

Citation Format: Liang DH, Patel A, Ensor JE, Patel TA, Chang JC, Rodriguez AA. Cell-free DNA as molecular tool for monitoring disease progression and response to therapy in breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-03-05.

Abstract P6-15-01: Triple negative breast cancer is vulnerable to Pan-HER, an antibody mixture simultaneously targeting EGFR, HER2 and HER3

Background: Triple negative breast cancer (TNBC) is a highly heterogeneous and aggressive subtype of cancer, lacking expression of estrogen and progesterone receptors as well as human epidermal growth factor receptor (HER) 2 protein. Limited standard therapeutic options, absence of effective targeted therapies, and early metastatic spread have contributed to poor prognosis and outcomes associated with this disease. Although overexpression of EGFR has been reported in nearly 80% TNBC, EGFR-targeted therapy has yielded little clinical benefit, and the outcome is still under debate. In conjunction, we also found mixed effects of EGFR-targeted therapy on TNBC xenograft tumors despite significant target engagement, suggesting that tumor heterogeneity and compensating mechanisms may contribute to the variable drug responses to the EGFR-targeted therapy. Recently, we reported superior anti-cancer effects of Pan-HER, a mixture of antibodies targeting the HER family members EGFR, HER2 and HER3 on various types of cancer by overcoming drug resistance and tumor heterogeneity. To this end, we hypothesized that Pan-HER can effectively inhibit tumor growth in TNBC by inhibiting tumor heterogeneity and drug resistance.

Objective: The goal of this study is to test the effect of Pan-HER antibody mixture (Sym013) on tumor growth and recurrence of 14 patient-derived (PDX) TNBC orthotopic xenograft tumor models and to investigate molecular biomarkers which can predict drug response to Pan-HER.

Methods: We evaluated in-vivo anti-tumor effects of Pan-HER (50 mg/kg, i.p. three times/week, 10 doses in total for 3 weeks) over vehicle on tumor growth and tumor recurrence on 14 PDX TNBC models with known expression levels of EGFR and HER3 (n=3/group). HER family proteins and related downstream molecules (Akt, Erk, Stat3, FAK) in the tumor tissues were evaluated by Western blot assay and immunohistochemistry analysis. Additionally, using dCHIP and ingenuity pathway analysis, we compared microarray data from the tested cohorts and other TNBC PDX models with known HER family receptor status.

Results: We found that Pan-HER alone effectively inhibited tumor growth in all 14 PDX models and showed statistical significance (p=0.0103) when compared to the vehicle groups. Among these, one PDX model, BCM-3186, showed substantial tumor reduction and additional two (MC1 and BCM-4913) showed complete response with no recurrence after the last treatment of Pan-HER. The significant anti-tumor effects of Pan-HER were positively correlated with inhibition of phosphorylation and expression of EGFR, HER3, Akt, Erk, and FAK, but not Stat3, and this was consistent in all PDX models tested. Additionally, the microarray and the pathway enrichment analyses suggest that loss of PTEN expression and up-regulation of FAK and RAS pathways may be the predictive markers for the Pan-HER drug response in TNBC.

Conclusion: Our in-vivo data suggest that simultaneous targeting of the three HER family receptors is a potential new approach for treatment of TNBC. Further confirmation of our in-vivo results will warrant a phase I clinical trial and lend support to single agent Pan-HER as a viable treatment strategy for TNBC patients in the clinic.

Citation Format: Choi DS, Qian W, Davila-Gonzalez D, Ensor JE, Lantto J, Kragh M, Horak ID, Chang JC. Triple negative breast cancer is vulnerable to Pan-HER, an antibody mixture simultaneously targeting EGFR, HER2 and HER3. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-15-01.

Abstract OT1-03-07: A randomized, placebo-controlled phase 2 study of paclitaxel in combination with reparixin compared to paclitaxel alone as front-line therapy for triple-negative breast cancer (fRida)

Background: Breast cancer stem cells (BCSC) have the ability to self renew and generate the full range of cells that make up a bulk tumor. Experimental models and retrospective clinical observations point to BCSC as responsible for tumor recurrence and metastasis. CXCR1, one of the receptors for CXCL8, has been identified on BCSC. Reparixin, an allosteric inhibitor of CXCR1, reduced BCSC in breast cancer xenografts (Ginestier C et al., JCI 2010) both as single agent and in combination with taxane chemotherapy. In a phase Ib trial in women with metastatic HER2-negative BC, the combination of escalating doses (400 to 1200 mg three times per day) of reparixin with weekly paclitaxel resulted in a low incidence and severity of adverse reactions, a sizeable response rate and time-to-progression, with some long-term responders (Schott AF et al., SABC 2014).

Trial Design: In this randomized, double-blind phase 2 trial patients will be randomized (1:1) to paclitaxel 80 mg/m2 on days 1, 8 and 15 of 28-day cycles in combination with reparixin or placebo oral tablets 1200 mg three times daily on days 1-21. Treatment continues until disease progression, unacceptable toxicity or withdrawal of consent. An independent Data Monitoring Committee has been appointed to oversee the trial. An independent Radiology Review will be performed for analysis of primary and secondary endpoints. Disease response will be assessed every 8 weeks. Patients will be followed up to 12 months after last enrolled patient completes treatment.

Eligibility Criteria: Patients must be female aged ≥18 years with untreated metastatic TNBC who have relapsed &gt;12 and &gt;6 months after the end of a taxane- or non taxane-based (neo)adjuvant chemotherapy regimen, respectively. They must have measurable disease, ECOG PS of 0-1, adequate organ function, and no history or evidence of brain metastases (brain CT or MRI required). Tumor tissue must be available from a metastatic site or from primary tumor for confirmation of diagnosis and correlative studies. Key exclusion criteria are pre-existing peripheral neuropathy G&gt;1 and any disease significantly affecting gastrointestinal function.

Specific Aims: Primary: to evaluate progression-free survival (PFS) rate by independent assessment.

Secondary: to determine median PFS, overall survival (OS), objective response rates and safety of the combination treatment.

Exploratory: to determine median time to new tumor metastasis (TTM), proportion of patients progressing with new metastatic lesions, incidence and severity of peripheral neuropathy, and to evaluate BCSC in metastatic tissue

Statistical Methods: The trial design provides 80% power to detect an increase in 6 month PFS from 30% to 50% with a 2-sided 5% significance level (Chi-square test). Kaplan-Meier curves will be produced for median PFS, OS outcomes and exploratory median TTM. Appropriate descriptive statistics will be provided for safety variables.

Present Accrual and Target Accrual: Target accrual is 190 patients. Patients will be enrolled internationally in US and Europe.

Contact Information: info@dompe.com

Citation Format: Chang JC, Schott AF, Wicha MS, Cristofanilli M, Ruffini PA, McCanna S, Goldstein LJ. A randomized, placebo-controlled phase 2 study of paclitaxel in combination with reparixin compared to paclitaxel alone as front-line therapy for triple-negative breast cancer (fRida). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT1-03-07.

Emergence of a sylvatic enzootic formosan ferret badger-associated rabies in Taiwan and the geographical separation of two phylogenetic groups of rabies viruses

Taiwan had been declared rabies-free in humans and domestic animals for five decades until July 2013, when surprisingly, three Formosan ferret badgers (FB) were diagnosed with rabies. Since then, a variety of wild carnivores and other wildlife species have been found dead, neurologically ill, or exhibiting aggressive behaviors around the island. To determine the affected animal species, geographic areas, and environments, animal bodies were examined for rabies by direct fluorescent antibody test (FAT). The viral genomes from the brains of selected rabid animals were sequenced for the phylogeny of rabies viruses (RABV). Out of a total of 1016 wild carnivores, 276/831 (33.2%) Formosan FBs were FAT positive, with occasional biting incidents in 1 dog and suspected spillover in 1 house shrew. All other animals tested, including dogs, cats, bats, mice, house shrews, and squirrels, were rabies-negative. The rabies was badger-associated and confined to nine counties/cities in sylvatic environments. Phylogeny of nucleoprotein and glycoprotein genes from 59 Formosan FB-associated RABV revealed them to be clustered in two distinct groups, TWI and TWII, consistent with the geographic segregation into western and eastern Taiwan provided by the Central Mountain Range and into northern rabies-free and central-southern rabies-affected regions by a river bisecting western Taiwan. The unique features of geographic and genetic segregation, sylvatic enzooticity, and FB-association of RABV suggest a logical strategy for the control of rabies in this nation.

Drug-repositioning screening identified piperlongumine as a direct STAT3 inhibitor with potent activity against breast cancer

Signal transducer and activator of transcription (STAT) 3 regulates many cardinal features of cancer including cancer cell growth, apoptosis resistance, DNA damage response, metastasis, immune escape, tumor angiogenesis, the Warburg effect and oncogene addiction and has been validated as a drug target for cancer therapy. Several strategies have been used to identify agents that target Stat3 in breast cancer but none has yet entered into clinical use. We used a high-throughput fluorescence microscopy search strategy to identify compounds in a drug-repositioning library (Prestwick library) that block ligand-induced nuclear translocation of Stat3 and identified piperlongumine (PL), a natural product isolated from the fruit of the pepper Piper longum. PL inhibited Stat3 nuclear translocation, inhibited ligand-induced and constitutive Stat3 phosphorylation, and modulated expression of multiple Stat3-regulated genes. Surface plasmon resonance assay revealed that PL directly inhibited binding of Stat3 to its phosphotyrosyl peptide ligand. Phosphoprotein antibody array analysis revealed that PL does not modulate kinases known to activate Stat3 such as Janus kinases, Src kinase family members or receptor tyrosine kinases. PL inhibited anchorage-independent and anchorage-dependent growth of multiple breast cancer cell lines having increased pStat3 or total Stat3, and induced apoptosis. PL also inhibited mammosphere formation by tumor cells from patient-derived xenografts. PL's antitumorigenic function was causally linked to its Stat3-inhibitory effect. PL was non-toxic in mice up to a dose of 30 mg/kg/day for 14 days and caused regression of breast cancer cell line xenografts in nude mice. Thus, PL represents a promising new agent for rapid entry into the clinic for use in treating breast cancer, as well as other cancers in which Stat3 has a role.

Microdecompression in spinal stenosis: a review

A goal of surgical treatment is to effectively treat pathology with minimizing injury of normal tissue. Microdecompression techniques are traditionally defined as procedures performed with a small incision using magnification and minimization of destruction to non-pathologic tissues. The good candidates are patients diagnosed of spinal stenosis who fail an appropriate course of non-operative management. These patients should have radiographic evidence of localized spinal stenosis without associated structural instability. Various techniques of microdecompression have been introduced until now. Although more technically challenging, microdecompression have produced long-lasting favorable outcomes via proper patient selection and surgeon training. In addition, the minimally invasive access techniques can greaten the results of microdecompression in the acute postoperative period. Through advanced minimally invasive techniques, the microdecompression will evolve in the future for sure.

Role of the bicarbonate-responsive soluble adenylyl cyclase in pH sensing and metabolic regulation

The evolutionarily conserved soluble adenylyl cyclase (sAC, adcy10) was recently identified as a unique source of cAMP in the cytoplasm and the nucleus. Its activity is regulated by bicarbonate and fine-tuned by calcium. As such, and in conjunction with carbonic anhydrase (CA), sAC constitutes an HCO⁻₃/CO⁻₂/pH sensor. In both alpha-intercalated cells of the collecting duct and the clear cells of the epididymis, sAC is expressed at significant level and involved in pH homeostasis via apical recruitment of vacuolar H⁺-ATPase (VHA) in a PKA-dependent manner. In addition to maintenance of pH homeostasis, sAC is also involved in metabolic regulation such as coupling of Krebs cycle to oxidative phosphorylation via bicarbonate/CO₂ sensing. Additionally, sAC also regulates CFTR channel and plays an important role in regulation of barrier function and apoptosis. These observations suggest that sAC, via bicarbonate-sensing, plays an important role in maintaining homeostatic status of cells against fluctuations in their microenvironment.

Abstract PD1-2: PIK3CA mutations and/or low PTEN predict resistance to combined anti-HER2 therapy with lapatinib and trastuzumab and without chemotherapy in TBCRC006, a neoadjuvant trial of HER2-positive breast cancer patients

We have recently reported that in patients with HER2-positive breast cancer, neoadjuvant targeted therapy with lapatinib and trastuzumab to more completely block the HER receptor layer, combined with endocrine therapy (in ER-positive tumors) and without chemotherapy led to a substantial 27% pathologic complete response (pCR) rate in the breast. Activation of downstream signaling pathways may lead to resistance to therapies targeting the HER pathway receptors. Aberrant activation of the PI3K pathway via decreased levels of PTEN and/or the presence of activating PIK3CA mutations has been implicated in resistance to targeted anti-HER2 therapy, but results of clinical trials are all confounded by the co-administration of chemotherapy and are inconsistent. We sought to clarify the role of these variables in predicting pCR, a surrogate for long-term outcome, in patients treated with potent targeted therapy alone in a prospective Phase II neoadjuvant trial in patients with HER2-positive breast cancer.

Patients with large tumors (median 6 cm) were given 12 weeks of lapatinib plus trastuzumab followed by surgery (Rimawi et al. JCO, 2013). Serial tissue biopsies were obtained from study participants. For this study, we focused on baseline pre-treatment characteristics. PTEN protein levels were measured by IHC and scored using the H-score. PIK3CA mutations were identified on extracted DNA using multiplex PCR with targeted next generation sequencing (the Ion Torrent 50-gene cancer mutation panel).

Of 64 evaluable patients, tissue was available on 59 for PTEN IHC, and sufficient DNA was available on 33 for the mutation panel. PTEN median H-score was 100 (range 0-300). PTEN status when dichotomized by the median was correlated with pCR (32% in high PTEN vs. 9% in low PTEN, p = 0.04). Activating PIK3CA mutations were identified in 12 out of 33 tumors (36%; 3 mutations in the helical and 9 in the catalytic domain) and were independent of ER status. None of the patients whose tumors harbored a PIK3CA mutation achieved pCR (p = 0.06). There was no association between PTEN status and PIK3CA mutation suggesting they are independent variables (p = 0.44). When PIK3CA mutations were considered together with PTEN status, there were 31 cases with data on both. The overall pCR rate in this cohort was 16% (lower than pCR rate observed in the overall trial). However, 0/17 cases (0%) with a mutation and/or PTEN low expression (&lt;100 H score) had a pCR compared to 5/14 cases (36%) with PI3KCA wild type and high PTEN levels (p = 0.01).

We conclude that PI3K pathway activation downstream of HER2 as a result of either low PTEN or activating PIK3CA mutation results in resistance to the combination of lapatinib and trastuzumab. This is the first report on patient tissue samples from a neoadjuvant trial using the combination of lapatinib and trastuzumab without chemotherapy. If validated in a larger cohort, our findings suggest that patients with HER2 positive tumors and who also harbor aberrant downstream PI3K pathway activation may benefit from the addition of PI3K/Akt/mTOR inhibitors to potent HER2 blockade.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD1-2.

Abstract P4-06-01: Expression and DNA copy number profiling suggest novel therapeutic approaches for triple negative breast cancer subtypes

The aggressive triple negative breast cancers (TNBCs), which lack ER, PR and HER2, comprise a high-risk subset of human breast cancers which remain poorly characterized and lack effective treatments. While recent meta-analyses indicate the complexity of these tumors, no robust independently validated phenotypes have been defined. We have identified four distinct molecular subtypes through independent non-negative matrix factorization of expression data from 84 Discovery and 114 Validation Set TNBCs profiled at a single institution, with matching CNV data (SNP array). We then classified 485 publically available TNBCs via a centroid signature of only 80 genes. All three sets supported stratification of tumors by cell cycle, DNA repair, and immunological signaling pathways that have significantly different clinical outcomes. The first subtype, composed of intermediate grade tumors, resembles the “Molecular Apocrine” or “Luminal AR” subtype described previously and was defined by enrichment of prolactin, aryl hydrocarbon receptor, and ERBB4 signaling with activated downstream expression patterns of ESR1 signaling. Large deletions of chromosome 6 were specific to this subtype. While focal deletions at 14q21.2 and 12q13.13 were present in &gt;60% of tumors of the other subtypes, the genes at these loci (FOXA1 and ERBB3) were overexpressed in the first subtype. Inhibitors of AR and MUC1, both overexpressed, may prove effective for these tumors. A second subtype defined as “Claudin-Low” or “Mesenchymal Stem-Like” showed overexpression of markers of mesenchymal lineage (ADIPOQ and OGN). Targets responsive to beta-blockers (ADRB2), and targetable molecules associated with platelet and endothelial function (EDNRB, PLA2G2A, PTGER3/4, PTGFR, PTGFRA) were also upregulated. Two basal-like subtypes were found with significant differences in DFS and OS, even after correction for available clinical covariates. The high-risk (31% 5-year DFS), low immune function subtype was regulated by SOX 10, 8, and 6 and had unique copy-number driven expression of FGFR2. The second, low-risk (78% 5-year DFS) basal-like subtype was enriched for overexpression of many immune pathways, regulated by increased STAT1 and activated STAT downstream signaling, as well as exclusive upregulation of CTLA4. This subtype also had the lowest tumor cell fraction as calculated by allele specific copy number analysis of tumors (ASCAT). Both basal-like subtypes expressed TTK, CHEK1, TOP2A, and AURKA. CDK1 was correlated with copy number variation at 10q21.1. We proposed and validated four molecular subtypes of TNBC before applying the resulting gene signature to 7 external expression sets. The described subtypes vary by clinical behavior and inferred biology. Each subtype appears to have specific gene expression regulated by copy number variation and a set of genes targetable by currently available agents. These findings further define the heterogeneity of TNBCs and suggest potential therapeutic targets for each subtype.

This work was supported by a Promise grant from the Susan G. Komen for the Cure Foundation (KG081694).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-06-01.

Abstract P5-03-12: Targeting breast cancer stem cells using the autopahgy inhibitor N-Acetyl cysteine

Introduction: One in eight women is diagnosed with breast cancer in the United States. The most aggressive form of breast cancer is the “triple negative breast cancer” (TNBCs), where there is a lack of expression of all three receptors, namely ER, PR and HER2 and a lack of targeted therapies lead to the highest relapse rate in breast cancer. This makes it imperative to identify and target the mechanism of relapse of this cancer. We have recently identified autophagy as a mechanism of tumor resistant cell survival in breast cancer. We have demonstrated an increase in autophagy in chemotherapy treated patients. Further, we have shown that addition of a stem cell inhibitor against NOTCH reduces autophagy and stem cells population. In order to eliminate these tumor resistant cells from surviving chemotherapy, we plan to target the cell survival pathway of autophagy using N-acetyl csyteine as a novel inhibitor.

Materials and Methods: We treated three triple negative cell lines (SUM159, BT549 and MDA-MB231) with varying concentrations of N-acetyl cysteine and determined its impact on tumor initiating cells via mammosphere formation and FACS sorting of CD44hi/CD24low cells. N-acetyl cysteine affects mitochondrial metabolism so we tested its impact on mitochondrial DNA mass.

Results: N-acetyl cysteine significantly decreased TIC population as evidenced by the remarkable reduction in mammosphere formation efficiency and levels of CD44hi/24low cells at 1 and 10uM in all three cell lines. In two cells lines we have demonstrated that there is a significant increase in mitochondrial mass upon treatment of NAC.

Conclusion: We have currently determined that N-acetyl cysteine works via autophagy and eliminates tumor initiating cell population. We have also demonstrated that this involves changing the mitochondrial mass and overall changes in the metabolism of these cells. This novel interlink between mitochondrial metabolism and autophagy provided a new insight into the role of tumor initiating cells in breast cancer and possible new approaches to treat therapy resistance in triple negative breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-12.

Abstract P5-03-03: Antitumor Activity and Cancer Stem Cells Effect of Cetuximab in Combination with Ixabepilone in Triple Negative Breast Cancers (TNBC)

Purpose: The ErbB family, including EGFR, has been demonstrated to play key roles in metastasis, tumorigenesis, cell proliferation, and drug resistance. Recently, these characteristics have been linked to a small subpopulation of cells classified as cancer stem cells (CSCs) which are believed to be responsible for tumor initiation and maintenance. Ixabepilone is the microtubule-stabilizing agent has been expected to be more sensitive than the conventional taxanes. The aim of this study was to investigate whether the EGFR monoclonocal antibody cetuximab, in combination with ixabepilone is a more effective treatment, and kill cancer stem cells more effectively as compared to chemotherapy alone in TNBC.

Experimental Design and Results: Breast CSC populations were evaluated with FACS analysis (CD44+ and CD24−/low, or Aldefluor+) and mammosphere formation efficiency (MSFE). In vitro, we demonstrated that in triple negative cell lines (MDA-MB-231 and SUM159), cancer stem cell populations were decreased after treatment of cetuximab, or cetuximab plus ixabepilone. In vivo, cetuximab in combination with ixabepilone treatment caused significant tumor regression (cetuximab vs. cetuximab+ ixabepilone; tumor volume fold change P &lt;0.05 (MDA-MB-231), P &lt;0.0001 (SUM159) in triple negative breast cancer xenografts. Thus, cetuximab decreased CSC population in xenograft tumors. Decrease in autophagy (LC3b, p62 and autophagosomes) were seen in cetuximab-treated tumors.

Conclusions: These studies demonstrate that cetuximab in combination with ixabepilone is more effective than chemotherapy alone in TNBC by affecting CSCs, as well as bulk tumor. These data support a neoadjuvant phase II study comparing ixabepilone vs. ixabepilone +cetuximab in TNBC patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-03.

Abstract S5-8: Parallel upregulation of Bcl2 and estrogen receptor (ER) expression in HER2+ breast cancer patients treated with neoadjuvant lapatinib

Background: We previously showed in HER2+ models of breast cancer (BC) that potent inhibition of the HER receptor layer can lead to re-expression of estrogen receptor (ER) or activation of the ER pathway. Consequently, the anti-apoptotic ER gene product Bcl2 is upregulated, resulting in enhanced tumor cell survival and treatment resistance. In this study, we investigated whether Bcl2 and ER expression levels are simultaneously increased by neoadjuvant treatment with the dual HER1/2 tyrosine kinase inhibitor lapatinib in HER2+ BC patients.

Methods: In a neoadjuvant phase II clinical trial 49 HER2+ BC patients were treated with lapatinib as a single agent for 6 weeks, followed by trastuzumab/docetaxel for 12 weeks before surgery. Tumor specimens were prospectively collected at different time-points during lapatinib treatment (baseline, and weeks 2 and 4). Bcl2, ER, progesterone receptor (PR), total (t) and phosphorylated (p)-HER2, and Ki67 were assessed by immunohistochemistry. Spearman correlation was used to evaluate the association among the biomarkers at baseline, and the correlation of their changes over time. Fisher's Exact test and non-parametric Wilcoxon rank sum test were used respectively to determine if the frequency and the magnitude of Bcl2 expression changes were associated with baseline ER status.

Results: 35/49 HER2+ tumor specimens (71%) were available for baseline evaluation of Bcl2 and ER. Of those, 12 (34%) were ER-positive (Allred score ≥ 3) and 23 (66%) ER-negative. Baseline Bcl2 expression correlated positively with ER (r = .75; p &lt; .0001) and PR (r = .53; p = .0015), and inversely with t-HER2 (r = −.43; p = .0097). ER baseline expression correlated positively with PR (r = .57; p = .0004), and inversely with t and p-HER2 (r = −.55; p = .0005, and r = −.37; p = .0282, respectively) and Ki67 (r = −.39; p = .0271). Bcl2 changes at week 2 (w2) positively correlated with changes in both ER and PR levels (r = .70; p = .0002 and r = .57; p = .0076, respectively). Additionally, the increase in Bcl2 expression, observed in 9 of the 23 (39%) tumors with tissue available at w2, was significantly more frequent (p = .0147) and of greater magnitude (p = .0001) in ER-pos vs. ER-neg tumors — 8/9 ER-pos tumors at w2 (including 3 converted from ER-neg by lapatinib) had increased Bcl2, while only 1 of the 14 (7%) ER-neg tumors (at baseline and w2) had increased Bcl2. The expression of ER itself at w2 also increased in 3 out of the 6 (50%) tumors which were originally ER-pos and had tissue available at w2, and in all of them Bcl2 increased in parallel. Of note, the single baseline ER-pos tumor that showed a reduction in ER at w2 had a parallel decrease in Bcl2. Similar observations or trends were found at week 4.

Conclusion: Our study suggests that Bcl2 is upregulated as a result of enhanced/restored ER activity upon anti-HER2 therapy with lapatinib in HER2+ tumors. This further supports the use of endocrine along with anti-HER-2 therapy to block this escape pathway which could otherwise cause treatment resistance. In addition, the ER re-expression with lapatinib treatment observed in this study emphasizes the need to re-biopsy HER2+/ER− patients receiving anti-HER2 therapy and to add endocrine therapy if the tumor becomes ER-positive.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr S5-8.

Abstract P6-07-11: Is the prognosis of lymphotropic invasive micropapillary carcinoma worse than invasive ductal carcinoma?: A population-based study of 645 patients

Purpose: Invasive micropapillary carcinoma (IMPC) is an uncommon distinct variant of breast carcinoma and is associated with an increased risk for regional lymph node metastases. Therefore, IMPC is considered to have an unfavorable prognosis when compared to invasive ductal carcinoma (IDC). The prognostic factors for IMPC are not well characterized due to the relative scarcity of cases reported in the literature.

Methods: We analyzed the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database to evaluate prognostic factors of a population of 645 breast IMPC patients and 300,060 breast IDC patients reported between 2001 and 2008. Using univariate and multivariate analyses, hazard ratios (HR) were calculated for disease-specific (DSS) and overall survival (OS) for these patients using parameters such as patient age at diagnosis, histological grade, ER status, PR status, tumor size, and degree of lymph node positivity. Subset analysis of high grade, lymph node-positive patients was performed to compare DSS and OS between IMPC and IDC.

Results: The 5-year DSS and OS for IMPC patients were 92.1% and 84.6% compared to 5-year DSS and OS of 88.5% and 80.2% for IDC patients. At presentation, TNM staging of IMPC cases was similar to IDC except for a higher percentage of LN metastases (52.4% in IMPC vs. 34.7% in IDC). Of those with known estrogen receptor (ER) status, 84.2% of IMPC cases were ER-positive, which was associated with better DSS (Hazard Ratio (HR) 0.36, p &lt; 0.002) and OS (HR 0.62, p = 0.072). Patients with four or more positive lymph nodes had worse DSS (HR 7.1, p &lt; 0.0001) and OS (HR 3.2, p &lt; 0.0001) than node-negative patients, but those with one to three positive lymph nodes had similar DSS (HR 1.04, p = 0.96) and OS (HR 0.99, p = 0.97) as node-negative patients. In the subset of patients with high grade, node-positive breast carcinoma, patients with micropapillary histology had better DSS (p &lt; 0.03) and a trend towards better OS (p = 0.12) than high grade, node-positive invasive ductal carcinoma. This subset of IMPC patients also had a higher percentage of ER-positive tumors (77%) compared to IDC patients (56%).

Conclusions: While IMPC has a high propensity for lymph node metastasis, it has a disease-specific and overall prognosis that compares favorably to IDC. The higher percentage of hormone-receptor positivity may account for this survival advantage, even in high grade, node-positive disease. Therefore, estrogen-receptor-negativity or having four or more positive lymph nodes at presentation may potentially serve as prognostic markers for IMPC patients. In this study population, patients with one to three positive lymph nodes have DSS and OS similar to node-negative patients. Additional clinical studies are warranted to further investigate this observation. This is the largest study of IMPC to date, and these findings help our understanding of this uncommon histological variant of breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-11.

Abstract P6-11-12: Nanoparticle-enhanced chemotherapeutics delivery in drug-resistant triple-negative breast cancer

Chemotherapeutics delivery is generally poor in tumors characterized by rapid perfusion and low blood volume fraction. Systemically administered nanoparticles can be engineered to overcome abnormal flow conditions to act as intravascular drug depots for the localized delivery of high concentrations of chemotherapeutics. The feasibility of this approach was first demonstrated using melanoma, and is now being further investigated using well-characterized human triple-negative breast cancer biopsies implanted into mice. Intravital microscopy studies of human cancer-in-mice selected for differing vascular morphologies have yielded intriguing preliminary data regarding the role of tumor vascularity in drug and particle delivery. The first-pass perfusion of a 40kDa dextran tracer revealed that BCM-2665 tumors are perfused ∼6x more rapidly than BCM-4195 tumors (11.3 ± 2.3s vs. 67.6 ± 11.0) and contain ∼30% lower volume fraction of blood (0.046 ± 0.011 vs. 0.062 ± 0.015). Interestingly, flow parameters that adversely impact drug accumulation appear to favor plateloid particle accumulation. BCM-2665 xenografts receiving an i.v. injection of 1000×400 nm particles show ∼10x more particle accumulation than BCM-4195 tumors (24.8 ± 3.2 × 103/mm3 vs. 3.5 ± 0.4 × 103/mm3). The ability of these therapeutic particles to reach tumors appears to be primarily driven by flow-related parameters, which we characterize using a combination of intravital microscopy, computed tomography, and mathematical modeling. The total number of particles accumulated within a given tumor appears to be largely driven by the number of particles entering the tumor, since ∼65–70% of entering plateloid particles are retained by the tumor vasculature. This suggests that cytotoxic intravascular drug depots may be a promising strategy for increasing the efficiency of chemotherapeutics delivery to drug-resistant tumors and is the premise of ongoing therapeutic response studies. Clearly if more drugs can be delivered to the tumors, better outcomes can be expected for the patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-11-12.

Abstract P3-06-14: Identification of Prognosis-Relevant Subgroups in Patients with Chemoresistant Triple Negative Breast Cancer

Purpose: Triple-negative breast cancer (TNBC) is a highly heterogeneous disease. TNBC patients with pathologic complete response (pCR) have excellent survival, but those with residual disease after neoadjuvant chemotherapy have significantly worse outcome. However, some patients having extensive residual cancer burden after neoadjuvant chemotherapy do not relapse, and we hypothesize that there may be subgroups with diverse prognosis among these chemoresistant TNBC patients.

Methods: Forty-nine cases with residual cancer from 111 TNBC patients treated with neoadjuvant chemotherapy (in M.D. Anderson Cancer Center, 2000–2006) constituted the discovery cohort. Twenty-five chemoresistant samples from 47 neoadjuvant chemotherapy-treated TNBC (in Baylor College of Medicine and Methodist Hospital, 2002–2006) were chosen for validation. Extended validation was performed in 269 operable TNBC predicted to be chemoresistant (using a JAMA-published genomic predictor) from public databases.

Results: By comparing the gene expression data from cases in relapse with those from un-relapsed cases, we established a 7-gene prognostic signature (including AR, ESR2, GATA3, GBX2, KRT16, MMP28, and WNT11) using dChip and gene enrichment analyses. In the discovery cohort, the signature showed positive predictive value (PPV; i.e., cumulative relapse rate of patients predicted to relapse in 3 years) of 95.4% and negative predictive values (NPV; i.e., relapse-free survival of patients predicted not to relapse in 3 years) of 100%. In the validation cohort, the classifier predicted correctly with PPV of 75.0% and NPV of 76.9% at 3 years. Compared with patients predicted not to relapse, those predicted to relapse had a hazard ratio of 3.37 (95% CI, 1.15–9.85) for disease recurrence or death in 3 years. In an extended validation cohort of 269 patients, our signature discriminated chemoresistant TNBC in overall cohort (PPV, 52.4%; NPV, 77.7%; log rank P &lt; 0.0001), or each subset (e.g., log rank p = 0.001 for Rotterdam set; p = 0.013 for Frankfurt set), with adjusted overall hazard ratio of 2.07 (95% CI, 1.26–3.39). This signature was the only marker that could effectively predict the relapse in patients with chemoresistant TNBC. Of note, the subgroup predicted not to relapse was characterized by high expression of luminal-like genes (AR, GATA3), while the subgroup predicted to have high possibility of relapse was characterized by high expression of cancer stem cell and epithelial-to-mesenchymal transition associated genes (WNT11, MMP28). The former corresponded to the luminal AR subtype and the latter to the mesenchymal stem-like subtype, according to Pietenpol's TNBC subtype classification.

Conclusion: We developed a clinically useful prognostic signature for chemoresistant TNBC. For these chemoresistant TNBC patients, new therapeutic strategies targeting AR-activation or cancer stem cells need to be developed.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-14.