ART714 is a best-in-class antileukemic 2-carbon-linked dimeric artemisinin derivative

PURPOSE

It has become increasingly clear that new multiagent combination regimens are required to improve survival rates in acute myeloid leukemia (AML). We recently reported that ART631, a first-in-class 2-carbon-linked artemisinin-derived dimer (2C-ART), was not only efficacious as a component of a novel three-drug combination regimen to treat AML, but, like other synthetic artemisinin derivatives, demonstrated low clinical toxicity. However, we ultimately found ART631 to have suboptimal solubility and stability properties, thus limiting its potential for clinical development.

METHODS

We assessed 22 additional 2C-ARTs with documented in vivo antimalarial activity for antileukemic efficacy and physicochemical properties. Our strategy involved culling out 2C-ARTs inferior to ART631 with respect to potency, stability, and solubility in vitro, and then validating in vivo pharmacokinetics, pharmacodynamics, and efficacy of one 2C-ART lead compound.

RESULTS

Of the 22 2C-ARTs, ART714 was found to have the most optimal in vitro solubility, stability, and antileukemic efficacy, both alone and in combination with the BCL2 inhibitor venetoclax (VEN) and the kinase inhibitor sorafenib (SOR). ART714 was also highly effective in combination with VEN and the FMS-like tyrosine kinase 3 inhibitor gilteritinib (GILT) against MOLM14 AML xenografts.

CONCLUSION

We identified ART714 as our best-in-class antileukemic 2C-ART, based on in vitro potency and pharmacologic properties. We established its in vivo pharmacokinetics and demonstrated its in vitro cooperativity with VEN and SOR and in vivo activities of combinations of ART714, VEN, and GILT. Additional research is indicated to define the optimal niche for the use of ART714 in treatment of AML.

Deep dissection of the antiviral immune profile of patients with COVID-19

In light of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants potentially undermining humoral immunity, it is important to understand the fine specificity of the antiviral antibodies. We screened 20 COVID-19 patients for antibodies against 9 different SARS-CoV-2 proteins observing responses against the spike (S) proteins, the receptor-binding domain (RBD), and the nucleocapsid (N) protein which were of the IgG1 and IgG3 subtypes. Importantly, mutations which typically occur in the B.1.351 "South African" variant, significantly reduced the binding of anti-RBD antibodies. Nine of 20 patients were critically ill and were considered high-risk (HR). These patients showed significantly higher levels of transforming growth factor beta (TGF-β) and myeloid-derived suppressor cells (MDSC), and lower levels of CD4+ T cells expressing LAG-3 compared to standard-risk (SR) patients. HR patients evidenced significantly higher anti-S1/RBD IgG antibody levels and an increased neutralizing activity. Importantly, a large proportion of S protein-specific antibodies were glycosylation-dependent and we identified a number of immunodominant linear epitopes within the S1 and N proteins. Findings derived from this study will not only help us to identify the most relevant component of the anti-SARS-CoV-2 humoral immune response but will also enable us to design more meaningful immunomonitoring methods for anti-COVID-19 vaccines.

Prospective Observational Study of Bisphosphonate-Related Osteonecrosis of the Jaw in Multiple Myeloma: Microbiota Profiling and Cytokine Expression

PURPOSE

Define incidence and risk factors of osteonecrosis of the jaw (ONJ) and explore oral microbial signatures and host immune response as reflected by cytokine changes in saliva and serum in multiple myeloma (MM) patients on bisphosphate (BP) therapy.

PATIENTS AND METHODS

A single center observational prospective study of MM patients (n = 110) on >2 years of BP, none had ONJ at enrollment. Patients were followed every 3 months for 18 months with clinical/dental examination and serial measurements of inflammatory cytokines, bone turnover markers, and angiogenic growth factors. Oral microbiota was characterized by sequencing of 16S rRNA gene from saliva.

RESULTS

Over the study period 14 patients (13%) developed BRONJ, at a median of 5.7 years (95% CI: 1.9-12.0) from MM diagnosis. Chronic periodontal disease was the main clinically observed risk factor. Oral microbial profiling revealed lower bacterial richness/diversity in BRONJ. Streptococcus intermedius, S. mutans, and S. perioris were abundant in controls; S. sonstellatus and S anginosus were prevalent in BRONJ. In the saliva, at baseline patients who developed BRONJ had higher levels of MIP-1β; TNF-α and IL-6 compared to those without BRONJ, cytokine profile consistent with M-1 macrophage activation. In the serum, patients with BRONJ have significantly lower levels of TGF beta and VEGF over the study period.

CONCLUSION

Periodontal disease associated with low microbial diversity and predominance of invasive species with a proinflammatory cytokine profile leading to tissue damage and alteration of immunity seems to be the main culprit in pathogenesis of BRONJ.

Pre-Clinical Activity of Amino-Alcohol Dimeric Naphthoquinones as Potential Therapeutics for Acute Myeloid Leukemia

BACKGROUND

The clinical outcomes of patients with acute myeloid leukemia (AML) remain unsatisfactory, therefore the development of more efficacious and better-tolerated therapy for AML is critical. We have previously reported the anti-leukemic activity of synthetic halohydroxyl dimeric naphthoquinones (BiQ) and aziridinyl BiQ.

OBJECTIVE

This study aimed to improve the potency and bioavailability of BiQ compounds and investigate the anti-leukemic activity of the lead compound in vitro and in a human AML xenograft mouse model.

METHODS

We designed, synthesized, and performed structure-activity relationship of several rationally designed BiQ analogues that possess amino alcohol functional groups on the naphthoquinone core rings. The compounds were screened for anti-leukemic activity and the mechanism as well as in vivo tolerability and efficacy of our lead compound was investigated.

RESULTS

We report that a dimeric naphthoquinone (designated BaltBiQ) demonstrated potent nanomolar anti-leukemic activity in AML cell lines. BaltBiQ treatment resulted in the generation of reactive oxygen species, induction of DNA damage, and inhibition of indoleamine dioxygenase 1. Although BaltBiQ was tolerated well in vivo, it did not significantly improve survival as a single agent, but in combination with the specific Bcl-2 inhibitor, Venetoclax, tumor growth was significantly inhibited compared to untreated mice.

CONCLUSION

We synthesized a novel amino alcohol dimeric naphthoquinone, investigated its main mechanisms of action, reported its in vitro anti-AML cytotoxic activity, and showed its in vivo promising activity combined with a clinically available Bcl-2 inhibitor in a patient-derived xenograft model of AML.

Exosomal PD-L1 expression as non-invasive biomarker for immune checkpoint inhibitors in non-small cell lung cancer

The development of immune checkpoint inhibitors (ICIs) significantly improved survival outcomes of non-small cell lung cancer (NSCLC) patients compared to chemotherapy. However, identification of predictive exosomal biomarker to reduce the invasive biopsy as well as to understand the efficacy of ICIs in NSCLC patients are unexplored. In this investigation, we demonstrate for the first time exosomal PD-L1 expression as predictive biomarker (liquid biopsy) for immune checkpoint blockage with PD-1/PD-L1 inhibitors in advanced/metastatic NSCLC.

Plasma samples from NSCLC patients (n=25) with matched paired samples at baseline and after 8 weeks of PD-1 blockade (Nivolumab, pembrolizumab and atezolizumab) were utilized for exosomal PD-L1 analysis by immunoblot. No statistically significant differences were reported for PD-L1 changes between pretreatment samples and at 8 weeks in both progressive patients (p=0.3783) and non-progressing patients (p=0.8066). Interestingly, when considering PD-L1 changes at 8 weeks between patients with progressive disease and partial response/stable disease (non-progressors), a trend towards PD-L1 reduction was observed in the non-progressors group, albeit this difference was not statistically significant (p=0.1941) due to the small sample size. Interestingly, dynamic changes during treatment of exosomal PD-L1 expression, assessed as exosomal PD-L1 ratio between pretreated samples and after 8 weeks of treatment, predicted the outcome of ICI treated patients in terms of both PFS and OS.

In conclusion, reduced exosomal PD-L1 expression at 8 weeks observed in non-progressors suggesting that exosomal PD-L1 might be used as non-invasive serum marker for ICIs treatment in NSCLC patients.

Abstract P5-06-27: Circulating cancer associated macrophage-like cells (CAMLs) are early predictors of response to new line therapies in metastatic breast cancer

Background: Tumor-associated macrophages have been shown to play a critical role in metastasis, angiogenesis, and immune escape. Cancer associated macrophage-like cells (CAMLs) are circulating stromal cell with macrophage expression subtypes, detected in the peripheral blood of patients with solid tumors. We have previously shown that enlargement of CAML cells is an independent predictor of poorer overall survival and an indication of progression in patients with metastatic breast cancer (MBC). However changes in CAML sizes after induction of therapy has not been investigated. Here we evaluated the association between early changes in numbers and sizes of CAMLs as it relates to clinical response after induction of new therapy. Method: Peripheral blood samples from 29 patients with metastatic breast cancer who failed at least 2 prior lines of therapies were prospectively collected. Baseline (BL) blood samples were taken prior to initiation of a new therapy and the second samples (T1) were taken approximately 30 days after initiation of a new systemic therapy. Blood samples were filtered using CellSieveTM filtration. The quantity and size of CAMLs were measured then compared between the BL and T1 time points. Univariate analysis was used to determine the association of changes in CAML numbers and changes in CAML size, with objective response at the first follow up CT scan with progression free survival (PFS). Results: CAMLs were detected in 97% of BL samples (averaging 20.9 CAMLs/7.5ml blood) and 93% of T1 samples (averaging 18.5 CAMLs/7.5mL blood). At the time of the first follow up CT scan, 17 of 29 patients (58.6%) had progressive disease based on the RECIST criteria. Among those, 14 of 17 patients (82%) had an increase in CAML size (~85% overall enlargement) and 3/17 (18%) had a decrease CAML size (~60% overall shrinkage) in T1 samples compared to baseline. In contrast, 10 of 12 patients (83%) with clinical benefit, including stable disease and partial or complete response, had a 92% reduction in their CAML’s size and 2 of 12 patients (17%) had 61% enlargement in their CAML’s size after treatment. Overall, CAML size change after therapy induction was 83% accurate in predicting clinical benefit based on subsequent scans. Furthermore, patients with enlarging CAML size at T1 had significantly shorter PFS of 4 months compared to 10 months in patients with decreasing CAML size (HR 3.7; 95%CI1.5-10.1; p 0.020). Conclusion: CAMLs can be commonly found in most treatment-refractory metastatic breast cancer patients and their morphological size is clinically correlated to poorer survival. Our data suggests that monitoring the size changes of a patient’s CAMLs after 30 days of new treatment initiation may predict clinical benefit earlier than conventional scans and act as real time monitoring of MBCs response to new therapies. Additional studies are currently ongoing to validate these results.

Citation Format: Saranya Chumsri, Markus D. Lacher, William V. Williams, R. K. Alpaugh, Stuart S. Martin, Rena Lapidus, Cha-Mei Tang, Massimo Cristofanilli, Daniel L Adams. Circulating cancer associated macrophage-like cells (CAMLs) are early predictors of response to new line therapies in metastatic breast cancer [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 P5-06-27.

Liquid biopsy tracking of lung tumor evolutions over time

Introduction: The rise of the personalized era in lung cancer prompted the evaluation of novel diagnostic tools to overcome some of the limits of traditional tumor genotyping. Liquid biopsy refers to a multitude of minimally invasive techniques that can allow a real-time biomolecular characterization of the tumor through the analysis of human body fluids.Areas covered: Herein we provide a comprehensive overview of the role of liquid biopsy in lung cancer, mainly focusing on the most studied members of the liquid biopsy family, cell-free DNA (cfDNA) and circulating tumor cells (CTCs).Expert opinion: Among the different components of the large liquid biopsy family, cfDNA is the most studied and widely adopted source for tumor genotyping in lung cancer, already entered clinical practice for detection of both sensitizing and resistance EGFR mutations. However, the impressive technological advances made in the last few years are expanding its potential applications, allowing a more comprehensive plasma genotyping through next-generation sequencing and moving from advanced/metastatic disease to novel frontiers, such as early detection and minimal residual disease evaluation.

Upregulation of RASSF1A in Colon Cancer by Suppression of Angiogenesis Signaling and Akt Activation

BACKGROUND/AIMS

Silencing of tumor suppressor genes (TSGs) and promotion of angiogenesis are associated with tumor development and metastasis. However, little is known if angiogenic molecules directly control TSGs and vice versa.

METHODS

A regulatory link between angiogenesis and down regulation of TSGs was evaluated using an anti-cancer agent, andrographolide (AGP) in cancer cells, mouse xenograft tissues and patient derived organoids through gene/protein expression, gene silencing, and immunohistochemical analyses.

RESULTS

AGP treatment demonstrated significant expression of RASSF1A and PTEN TSGs in colon cancer and other cancer cells, mouse tissues and organoids. Depletion of RASSF1A with siRNA limited cyclin D1 and BAX expression. SiRNA depletion of PTEN, upstream regulator of RASSF1A resulted in a 50% reduction in RASSF1A expression. Histopathological analysis of the AGP treated tumor sections showed significant reduction in vessel size, microvascular density and tumor mitotic index suggesting suppression of angiogenesis. This was corroborated by protein analysis demonstrating significant reductions in angiogenesis signaling pathway molecules VEGF165, FOXM1, and pAkt, but significant elevation of the endogenous angiogenesis inhibitor Tsp-2. Treatment of cells with exogenous VEGF prevented the suppression of angiogenesis signaling by AGP, resulting in sustained expression of pAkt, an upstream down-regulator of RASSF1A. RASSF1A expression remained low in VEGF treated cells despite the addition of AGP.

CONCLUSION

Our results demonstrate for the first time that AGP induces RASSF1A expression in colon cancer cells and is dependent on angiogenesis signaling events. Therefore, our research may facilitate novel therapeutic options for advanced colon cancer therapy.

Abstract 1560: Real-time monitoring of solid tumor progression by circulating stromal cells from early- to late-stage disease

Background: Blood-based biomarkers (PSA, CEA, CA125) are used to track real-time progression of disease in parallel with imaging. However, while numerous blood biomarkers exist, they are specific to cancer type (i.e., PSA to prostate and CEA to colon) and may not appear in all diseased individuals. Recently, cancer-associated macrophage-like cells (CAMLs), a circulating stromal cell subtype, were identified in various solid cancer types, which were observed increasing in size and in hyperploidy during progressive disease. To assess whether CAML enlargement is a biomarker of progression/response, we tracked CAML growth/shrinkage in a pilot study of patients (n=34). Blood was drawn from patients with lung, prostate, or breast cancers over a 3-month period, baseline through 2 treatment cycles, followed by continued monitoring for 2 years. These data suggest that morphologic assessment of CAMLs (growth/hyperploidy) appear to parallel cancer progression, or response to treatment, in multiple solid tumors.

Methods: A prospective multi-institutional study used anonymized peripheral blood samples from 34 cancer patients undergoing therapy [stage I (n=2), II (n=3), III (n=8) & IV (n=21)] with breast (n=10), lung (n=16), & prostate (n=8). Samples were taken prior to therapy (BL), at 1 month (FU1) follow-up and a 3-month (FU2) follow-up, after induction of therapy. Blood was processed by the CellSieve™ microfiltration technique at 4 institutions and stained for cytokeratin 8, 18 and 19, CD14 and CD45. After identification and quantification, CAMLs were measured based on their hyperploidy and cell size.

Results: CAMLs were found in 97% of cancer patients at BL, 97% at FU1 and 91% of FU2. Over the 2-year follow-up, 7 patients showed no signs of clinical disease progression, while 27 patients had observable progression. Of the 7 patients who did not progress, only two had CAMLs of ≥50µm at BL and at FU1, but whose CAMLs shrunk to <50 µm by FU2. Of the 27 patients who progressed, 22 patients had ≥50µm CAMLs at all time points, while 5 patients had small <50µm CAMLs at BL. Interestingly, CAMLs in these 5 patients had enlarged to ≥50µm by the FU2 time point.

Conclusions: We show that increased polynucleation and CAML enlargement indicate shorter progression-free survival in a number of cancer types after baseline. By monitoring CAML changes over time for the 34 individual patients, we demonstrated correlation of ongoing progression, or response, in tumors to the enlargement or shrinkage in CAMLs at follow-up time points from treatment induction. This pilot study suggests that CAMLs have the potential to monitor the progression/regression of malignancy in real time and suggests the need for larger validation studies.

Citation Format: Daniel L. Adams, Raymond Bergan, Martin J. Edelman, Stuart S. Martin, Rena Lapidus, Saranya Chumsri, Cha-Mei Tang, Steven H. Lin. Real-time monitoring of solid tumor progression by circulating stromal cells from early- to late-stage disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1560.

Abstract 4455: Fatty acid synthase-induced S6Kinase facilitates USP11-eIF4B complex formation for sustained oncogenic translation in DLBCL

Fatty acid synthase (FASN) and protein translational machinery are two emergent therapeutic targets for cancer treatment, but their mutual dependency on each other for tumor propagation especially in diffuse B-cell large lymphoma (DLBCL) is still unknown. Therefore, we investigated the functional implication of enhanced FASN activity on protein translational machinery employing a panel of 7 DLCBL cell lines and 40 clinical samples. Inhibition of FASN activity by a specific inhibitor, C75 or shRNA mediated knockdown, suppressed de novo protein synthesis in SUDHL2, TMD8, Pfeiffer and HLY-1 (ABC-origin) cells, whereas SUDHL4, SUDHL6 and Toledo (GC-origin) cells showed minimal effect after C75 treatment or FASN knockdown. Assessing the core translational machinery, the eIF4B (eukaryotic initiation factor 4B) levels were depleted in a dose dependent manner of C75 treatment or shRNA mediated knock down of FASN in ABC-DLBCLs. Mechanistically, eIF4B undergoes ubiquitin mediated protein degradation upon FASN depletion. Depleting the expression of eIF4B significantly reduced the proliferative capacity of both FASN sensitive as well resistant DLBCL cells. Screening the interacting protein partners from available databases, we observed that USP11 interacts with and deubiquitinates eIF4B increasing its overall stability. Consistently, altering the expression of USP11 or its activity by either chemical inhibition or mutation significantly alters nascent peptide synthesis. Of functional significance, either down regulating USP11 or inhibition via small molecules significantly reduced the cell proliferation with increased apoptosis of both, FASN activity sensitive and resistant DLBCL cells. USP11 expression was also elevated in DLBCL tissues as evidenced by significantly higher staining. Significantly there is a strong correlation between USP11, FASN as well as eIF4B expression in DLBCL. Elucidating the basis for FASN not regulating GC DLBCL, we observed that sustained PI3K signalling in GC-DLBCL plays a key role in FASN dependent eIF4B stability. Detailed molecular analysis established that S6Kinase phosphorylates USP11 at Ser453, which regulates its interaction with, and stability of eIF4B thereby promoting proto-oncogene expression. These results together demonstrate that FASN activated S6Kinase induced eIF4B/USP11 axis is required for cell proliferation and survival by regulating the translation of proliferative and pro-survival mRNAs. Our findings support targeting the eIF4B/USP11 axis and provide a novel therapeutic option for patients with relapsed/refractory DLBCL.

Citation Format: Bandish Kapadia, Nahid Nanaji, Kavita Bhalla, Binny Bhandary, Rena Lapidus, Afshin Beheshti, Andrew Evens, Ronald Gartenhaus. Fatty acid synthase-induced S6Kinase facilitates USP11-eIF4B complex formation for sustained oncogenic translation in DLBCL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4455.

Abstract 2823: DNA methyltransferase inhibitors sensitize NSCLC cells to PARP inhibitors by induction of a double strand break repair defect

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death in the US. Poly (ADP-ribose) polymerase inhibitors (PARPi) show efficacy as radiosensitizers in NSCLC, but arguably have gained greater importance in cancer therapeutics by exhibiting synthetic lethality (SL) in tumors with defects in the homologous recombination (HR) pathway of double strand break repair (DSBR). Mechanistically, PARPi cytotoxicity is partially mediated through trapping of PARP1 at sites of DNA damage, with next generation PARPis such as talazoparib (Tal) being potent PARP trappers. Our group has previously demonstrated that combining Tal with a DNA methyltransferase inhibitor (DNMTi) enhances PARPi cytotoxicity in acute myeloid leukaemia and breast cancer models. DNMTis are cytosine analogs that become incorporated into replicating DNA, where they covalently bind their target enzyme DNMT1. When combined with PARPi, DNMTis enhance PARP trapping at damage sites, which collapse into cytotoxic double strand breaks (DSB) when encountered by a replication fork.

In the current study, we demonstrate synergistic cytotoxicity of Tal in combination with the DNMTi 5-azacytidine (Aza) in NSCLC cell lines by combination index analyses and colony forming assays. Further potentiation of Tal+Aza cytotoxicity is observed following induction of DNA damage via IR. These results were substantiated in an A549 xenograft model (n=8 per group) where Tal+Aza+IR significantly reduced tumor volume and increased survival compared to vehicle (p<0.001) or Tal+Aza without IR (p<0.05). We and others have previously reported that low dose DNMTi results in stable transcriptional changes in the cancer epigenome, including DNA damage response pathways. Here, we show by microarray analysis that NSCLC cell lines (A549, H23, H1299, H460) treated with Aza exhibit up- and downregulation of multiple genes in the DNA repair reactome, including decreased expression of the key HR-related gene FANCD2, and the non-homologous end joining (NHEJ) gene Ku80. These results were validated by mRNA and protein quantification in Aza-treated NSCLC cell lines and xenograft tumor samples. In keeping with a FANCD2-associated HR defect, Aza exposure is associated with reduced accumulation of RAD51 foci following IR, and reduced HR activity in an extrachromosomal HR assay. Additionally, increased sensitivity to IR post Aza treatment can be explained by decreased expression of NHEJ factor Ku80. These results indicate that Aza treatment in NSCLC induces a DSBR deficiency that can be targeted for SL by PARPi and can further sensitize to IR. Given these agents are currently in use in the clinic, this combination offers a promising therapeutic strategy that could be rapidly translated into clinical practice.

Citation Format: Rachel Abbotts, Michael Topper, Daniel Fontaine, Christopher Biondi, Eun Yong Choi, Rena Lapidus, Stephen Baylin, Feyruz Rassool. DNA methyltransferase inhibitors sensitize NSCLC cells to PARP inhibitors by induction of a double strand break repair defect [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2823.

Fatty Acid Synthase induced S6Kinase facilitates USP11-eIF4B complex formation for sustained oncogenic translation in DLBCL

Altered lipid metabolism and aberrant protein translation are strongly associated with cancerous outgrowth; however, the inter-regulation of these key processes is still underexplored in diffuse large B-cell lymphoma (DLBCL). Although fatty acid synthase (FASN) activity is reported to positively correlate with PI3K-Akt-mTOR pathway that can modulate protein synthesis, the precise impact of FASN inhibition on this process is still unknown. Herein, we demonstrate that attenuating FASN expression or its activity significantly reduces eIF4B (eukaryotic initiation factor 4B) levels and consequently overall protein translation. Through biochemical studies, we identified eIF4B as a bonafide substrate of USP11, which stabilizes and enhances eIF4B activity. Employing both pharmacological and genetic approaches, we establish that FASN-induced PI3K-S6Kinase signaling phosphorylates USP11 enhancing its interaction with eIF4B and thereby promoting oncogenic translation.

Abstract IA13: Combination of DNA methyltransferase and PARP inhibitors as a novel therapy strategy for multiple cancers: Key data in AML and triple negative breast cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors represent one of the most exciting recent developments in cancer therapy. While substantial efficacy has been shown with clinically available PARP inhibitors (PARPis), to date, in treatment of hereditary deletions of BRCA1/2 in breast and ovarian cancers, the high promise of these drugs has not yet been realized in sporadic cancers. We present here strong preclinical data for a novel, mechanistically based, combinatorial approach to using DNA methyltransferase inhibitors (DNMTis), such as decitabine (DAC) and 5-Azacytidine (5-AZA), with PARP inhibitors (PARPis) as a treatment strategy for acute myelogenous leukemias (AML) and triple negative breast cancer (TNBC). We have previously demonstrated that low doses of 5-AZA and DAC alone show efficacy in AML and TNBC, and propose treatment with PARPis to enhance sensitivity of cancer cells to DNMTis. The mechanistic rationale for our approach is based upon: 1) data from our group and others showing DNMT1 and PARP1 associate in a complex, and this association increases with DNA damage; 2) the fact that 5-AZA and DAC trap DNMTs led us to hypothesize that these drugs might also increase PARP trapping at DNA damage sites; and 3) the cytotoxicity of the most potent PARPis (e.g. BMN 673) appears to correlate with the degree of trapping of PARP1 in chromatin. We first find that in cultured human AML and TNBC cells, the DNMTis (5 to 20 nM DAC or 100 to 200nM 5-AZA) and PARPis (1 to 10 nM BMN 673) alone trap PARP into chromatin, and this effect is enhanced when the drugs are combined. In addition, the PARPi-DNMTi combination treatment of TNBC cell line MDA-MB-231 resulted in significantly enhanced retention of PARP1 and DNMT1 at sites of double strand breaks (DSBs) induced by laser microirradiation. Concomitant with this, the combined doses resulted in significant increases in cytotoxic DSBs, observed 4-24 hours after DSB induction, when compared to single-drug treatments. Homologous recombination (HR) DSB repair activity also appears decreased, as measured by GFP reporter assays.

In keeping with these findings, colony survival assays demonstrated that the combination treatment, compared to either drug alone, strongly inhibited colony formation of TNBC cell lines (N=4). Notably non-tumorigenic MCF10A cells showed no significant differences in colony numbers with single or combination drug treatments. Similar to TNBCs, AML cell lines (N=3) as well as primary AML cells (N=8) showed dramatic decreases in colonies in combination vs single agent drug treatments. In the most important translational implications of the preliminary studies, in in vivo therapy TNBC and AML models in immune-deficient mice, our low dose combinations of DNMTis and PARPis provide for potent anti-tumor responses. Mouse xenograft experiments using BRCA mutant TNBC cell line SUM149PT demonstrated that the combination treatment has a significant (p<0.05) survival advantage compared to control (vehicle), AZA (0.5mg/kg) or BMN (0.3 mg/kg) alone. Importantly, mouse MDA-MB-231 xenografts with intact BRCA1 showed significant survival with the combined drug treatment. Likewise in AML xenografts of MOLM14 and MV411 cell lines treated with the drug combination show significantly decrease leukemia burden, as measured by luciferase imaging. Our data suggest a novel use of both DNMTis and PARPis in a compelling therapeutic strategy for TNBCs independent of BRCA mutations and poor prognosis AML; the latter will be investigated in a clinical trial to be based at the University of Maryland and funded by Van Andel-SU2C.

Citation Format: Nidal Muvarak, Khadiza Chowdhury, Carine Robert, Xia Limin, Eun Yong Choi, Yi Cai, Marina Bellani, Michael Seidman, Maria R. Baer, Rena Lapidus, Stephen B. Baylin, Feyruz V. Rassool. Combination of DNA methyltransferase and PARP inhibitors as a novel therapy strategy for multiple cancers: Key data in AML and triple negative breast cancer [abstract]. In: Proceedings of the AACR International Conference: New Frontiers in Cancer Research; 2017 Jan 18-22; Cape Town, South Africa. Philadelphia (PA): AACR; Cancer Res 2017;77(22 Suppl):Abstract nr IA13.

Abstract 120: A study of in vitro and in vivo effects of a novel peptide and rhenium compounds on prostate cancer

Emerging evidence suggests that acquisition of the epithelial-to-mesenchymal transition (EMT), a process that resembles the genesis of cancer stem-like cells, contributes to tumor aggressiveness and is mediated by deregulated expression of microRNAs (miRNAs), such as miR-200 and let-7 family. Loss of miR-200 expression results in the over-expression of Lin28B, which is prevalent in human Prostate Cancer( PCa) . Lin28B is also known to block the processing of another miRNA (pre-let-7 and pri-let-7), resulting in decreased mature let-7, thereby leads to increased Suz12 and EZH2 expression, which are important components of the polycomb repressive complex 2 (PRC2). Thus, over- expression of Lin28B and loss of miR-200 and let-7 appear to be responsible for PCa aggressiveness. A group of novel rhenium compounds have shown promising anti-cancer properties in various cancer cell lines tested in our laboratories. Our current investigations show that re-expression of miR-200b, miR-200c, and let-7 could be achieved by treating cells with our newly developed rhenium compounds by down-regulating the expression of Lin28B and EZH2. Based on our preliminary results, we hypothesize that over-expression of Lin28B leads to the acquisition of invasive and metastatic characteristics in PCa cells (EMT-phenotype cells) via down-regulation of miR-200b and miR-200c, resulting in increased expression of Suz12, ZEB1, and ZEB2. We also hypothesize that over-expression of Lin28B represses the maturation of let-7 family, leading to increased expression of EZH2, and these processes can be attenuated by treatment of cells with novel rhenium compounds in vitro. Our experiments were done on prostate cancer cell lines derived from both Caucasian(CA) and African American (AA)patients and also biopsy samples obtained from both CA and AA patients at Henry Ford Hospital and Karmanos Cancer Center of Wayne State University, Detroit, MI. We confirmed using gene expression studies by micro array and Real-Time PCR and then data analysis by Ingenuity software systemthe validity of our hypothesis and continued our research by testing one of these rhenium compounds-RPR1 on prostate cancer model of nude mice at Greenbaum Cancer Center(GCC) of University of Maryland at Baltimore. In vitro studies by Real -Time PCR, Flow Cytometry, Western Blotting ,Smart-Flare technology, cell death and proliferation assays along with inhibition of spheroid forming assays showed efficacy of these rhenium compounds as anti cancer agents. In vivo studies also showed decrease of tumor volume and mass ,no toxicity, thus efficacy of these novel drugs. ACKNOWLEDGEMENT: Supported by NIH- 3R01CA164318-03S1 and NIH-T-34-GM100831, a NSF-VESTEM award and NSF-LSAMP award .

Citation Format: Hirendra N. Banerjee, Sasha Hodge, William Kahan, Santosh Mandal, David Weber, Rena Lapidus, Fazlul Sarkar, Somiranjan Ghosh. A study of in vitro and in vivo effects of a novel peptide and rhenium compounds on prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 120. doi:10.1158/1538-7445.AM2017-120

Abstract 1422: Enhancing the therapeutic effects of PARP inhibitors in combination DNA methyl transferase inhibitors, using low doses of ionizing radiation in non small cell lung cancers

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths in the US. Treatment most commonly relies on ionizing radiation (IR) and platinum-based DNA damaging agents, but long-term survival is poor and patients tend to suffer chronic side-effects due to the high radiation dose to the surrounding normal tissues. Therefore, new treatments are needed that can be used in combination lower radiation doses.

We have recently reported that low, non-cytotoxic doses Poly ADP ribose polymerase inhibitors (PARPi) Talazoparib in combination with DNA methyltransferase inhibitors (DNMTi) Decitabine (DAC) or azacytidine (AZA) significantly increase cytotoxicity in acute myeloid leukemia and breast cancer models in vitro and anti-tumor effects in vivo. Simultaneous administration of both inhibitors result in increased PARP binding in DNA, leading to higher levels of DNA double strand breaks (DSBs), yielding increased cytotoxicity, compared with each agent treatment alone.

We first studied the efficacy of Talazoparib and AZA combination therapy in multiple NSCLC cell lines (A549, H358 and H838) in vitro through colony forming assays. Results showed, compared to single agent treatments, combination drug treatment significantly decreased colony formation. Cell viability was also significantly decreased with the drug combination in MTS assays (P<0.05). These results also showed synergistic activity between the two drugs, with a combination index of less than 1 for all tested NSCLC cell lines. Importantly, the drug combination increased PARP trapping in chromatin and DSB formation, as measured by immunofluorescent staining for γH2AX. We next determined whether AZA/Talazoparib in combination with a single dose of radiation (2Gy) had an increased anti-cancer effect compared to each modality alone in in vivo mouse xenografts of NSCLC A549. While the combination of PARPi+DNMTi with radiation treatment decreased tumor growth, compared to PARPi/DNMTi alone or RT alone, no significant enhancement with radiation was observed. We next determined whether low doses of fractionated IR (2Gy 3 fractions) would improve the efficacy of DNTMi and PARPi combination treatment. In vitro studies with colony forming assays of NSCLC cell line A549 show that IR doses in combination with PARPi and DNMTi decrease clonogenicity, compared with non-IR controls. Furthermore, A549 xenografts were treated with the drug combination and then irradiated 1 week later with 2Gy daily for 3 consecutive days. Mice treated with the drug combination followed by IR had significant decreases in tumor volume and survival (P<0.05). This suggests that low doses of PARPi and DNMTi therapy in combination with low dose IR can potentially target NSCLC tumors. This represents a novel treatment approach for NSCLC patients that may reduce chronic side-effects of high dose IR.

Citation Format: Christopher Biondi, Daniel Fontaine, Lora Stojanovic, Pratik Nagaria, Rena Lapidus, Eun Yong Choi, Javed Mahmood, Stephen Baylin, Feyruz V. Rassool. Enhancing the therapeutic effects of PARP inhibitors in combination DNA methyl transferase inhibitors, using low doses of ionizing radiation in non small cell lung cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1422. doi:10.1158/1538-7445.AM2017-1422

Silencing of solute carrier family 13 member 5 disrupts energy homeostasis and inhibits proliferation of human hepatocarcinoma cells

The solute carrier family 13 member 5 (SLC13A5), a sodium-coupled citrate transporter, plays a key role in importing citrate from the circulation into liver cells. Recent evidence has revealed that SLC13A5 deletion protects mice from high-fat diet-induced hepatic steatosis and that mutation of the SLC13A5 orthologues in Drosophila melanogaster and Caenorhabditis elegans promotes longevity. However, despite the emerging importance of SLC13A5 in energy homeostasis, whether perturbation of SLC13A5 affects the metabolism and malignancy of hepatocellular carcinoma is unknown. Here, we sought to determine whether SLC13A5 regulates hepatic energy homeostasis and proliferation of hepatoma cells. RNAi-mediated silencing of SLC13A5 expression in two human hepatoma cell lines, HepG2 and Huh7, profoundly suppressed cell proliferation and colony formation, and induced cell cycle arrest accompanied by increased expression of cyclin-dependent kinase inhibitor p21 and decreased expression of cyclin B1. Furthermore, such suppressive effects were also observed on the growth of HepG2 cell-derived xenografts expressing SLC13A5-shRNA in nude mice. Metabolically, knockdown of SLC13A5 in HepG2 and Huh7 cells was associated with a decrease in intracellular levels of citrate, the ratio of ATP/ADP, phospholipid content, and ATP citrate lyase expression. Moreover, both in vitro and in vivo assays demonstrated that SLC13A5 depletion promotes activation of the AMP-activated protein kinase, which was accompanied by deactivation of oncogenic mechanistic target of rapamycin signaling. Together, our findings expand the role of SLC13A5 from facilitating hepatic energy homeostasis to influencing hepatoma cell proliferation and suggest a potential role of SLC13A5 in the progression of human hepatocellular carcinoma.

Abstract B30: Inhibition of eIF4E/MNK axis by novel MNKDAs reduces breast cancer tumor growth, migration, invasion and metastasis

Triple-negative breast cancer (TNBC) represents a molecularly heterogeneous subgrouping of high-risk breast tumors characterized by aggressive behavior, poor prognosis and lack of targeted therapeutic options. The translation initiation factor eIF4E, an oncogene essential for cap-dependent translation of specific mRNAs critical for cell division, cell survival, angiogenesis, and metastasis is commonly overexpressed in primary breast cancers including TNBC. eIF4E therapeutic targeting is considered novel and significant because tumor cells specifically overexpress eIF4E and develop an oncogene addiction to eIF4E, rendering the cells vulnerable to eIF4E inhibition, whereas normal cells are relatively insensitive. Phosphorylation of eIF4E at serine-209 is critical for the oncogenic activity of eIF4E, and it has been suggested that chemical compounds that prevent the phosphorylation of eIF4E could act as effective anticancer drugs. Herein, we report that a novel inhibitor of peIF4E function (Novel Retinamides, NRs), safely and potently suppresses breast tumor formation. Administration of novel retinamides (mnk degrading agents: MNKDAs) blocked the growth of primary breast tumors in MDA-MB-231 xenograft model, TNBC patient derived xenografts (PDX), and reduced the development of lung metastases in an invasive model. Mechanistically, NRs resulted in the degradation of MNKs (MNK1 and MNK2), a key kinase chiefly responsible for phosphorylating and activating eIF4E. This in turn hampered peIF4E involved translation initiation and activation of genes associated with cell proliferation and survival. Furthermore, MNK degradation by NRs also suppressed epithelial-to-mesenchymal transition, a process crucial for metastasis as evident by increased expression of E-cadherin and reduced expression of N-cadherin, fibronectin and vimentin; snail, slug, twist, fibronectin, claudin, lamin, TCF/ZEB-1, beta catenin, MMPs and vimentin. Taken together, the preclinical evidence of tumor regression and metastasis in TNBC models suggest that NRs offers considerable promise as new therapeutic candidate to target TNBC and metastatic breast cancer.

Citation Format: Senthilmurugan Ramalingam, Lalji Gediya, Vidya Ramamurthy, Yong Choi, Rena Lapidus, Njar Vincent. Inhibition of eIF4E/MNK axis by novel MNKDAs reduces breast cancer tumor growth, migration, invasion and metastasis. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Targeting the Vulnerabilities of Cancer; May 16-19, 2016; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(1_Suppl):Abstract nr B30.

Abstract LB-205: Combination of DNA methyltransferase and PARP inhibitors as a novel therapy strategy for poor prognosis acute myeloid leukemia and triple-negative breast cancers

Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) have shown efficacy in treatment of breast and ovarian cancers with hereditary deletions of BRCA1/2, but the high promise of these drugs has not yet been realized in sporadic cancers. We present here strong preclinical data for a novel, mechanistically based, combinatorial approach to using DNA methyltransferase inhibitors (DNMTi’s), such as decitabine (DAC) and 5-Azacytidine (5-AZA), with PARP inhibitors (PARPi’s) as a treatment strategy for acute myelogenous leukemias (AML) and estogen-, progesterone- and HER2-receptor negative, or triple negative breast cancer (TNBC). We have previously demonstrated that low doses of 5-AZA and DAC alone show efficacy in AML and TNBC, and propose treatment with PARPi's to enhance sensitivity of cancer cells to DNMTis. The mechanistic rationale for our approach is based upon: 1) data from our group and others showing DNMT1 and PARP1 associate in a complex, and this association increases with DNA damage; 2) the fact that 5-AZA and DAC trap DNMT's led us to hypothesize that these drugs might also increase PARP trapping at DNA damage sites; and 3) the cytotoxicity of the most potent PARPi's (e.g. Talazoparib) appears to correlate with the degree of trapping of PARP1 in chromatin. We find that in cultured human AML and TNBC cells, the DNMTi's (5 to 20 nM DAC or 100 to 200nM 5-AZA) and PARPi's (1 to 10 nM Talazoparib) alone trap PARP into chromatin, and this effect is enhanced when the drugs are combined. In addition, the PARPi-DNMTi combination treatment in TNBC MDA-MB-231 and AML MOLM-14 cell lines resulted in significantly increased DNA double strand breaks (DSBs) and enhanced retention of PARP1 and DNMT1 at laser microirradiation DNA damage sites. Compared with non-tumorigenic MCF10A cells, in TNBC cell lines (N = 4), the combined doses resulted in significant (p<0.05) increases in colony survival, when compared to single drug treatments. Similarly, AML cell lines (N = 3) as well as primary cells (N = 8) showed dramatic decreases (p<0.05) in colonies in combination vs single agent drug treatments. In the most important translational implications, mouse xenograft experiments, using BRCA mutant TNBC cell line SUM149PT and MDA-MB-231 with intact BRCA1, both models demonstrated that the combination treatment has a significant (p<0.05) survival advantage, compared to control (vehicle), AZA (0.5mg/kg) or BMN (0.3 mg/kg) alone. Likewise in AML xenografts of MOLM14 and MV411 cell lines with poor prognosis marker, FMS-like 3 internal tandem duplication (FLT3/ITD), the drug combination show (p<0.05) significantly decreased leukemia burden, as measured by luciferase imaging. Our data suggest a novel use of both DNMTi's and PARPi's in a compelling therapeutic strategy for TNBCs independent of BRCA mutations and poor prognosis AML; the latter will be investigated in a clinical trial funded by Van Andel-SU2C.

Citation Format: Feyruz V. Rassool, Nidal Muvarak, Khadiza Chowdury, Carine Robert, Limin Xia, Eun Yong Choi, Yi Cai, Marina Bellani, Ying Zou, Michael Seidman, Søren Bentzen, Maria Baer, Rena Lapidus, Stephen B. Baylin. Combination of DNA methyltransferase and PARP inhibitors as a novel therapy strategy for poor prognosis acute myeloid leukemia and triple-negative breast cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-205.

Abstract 2848: Combination of DNA methyltransferase and PARP inhibitors as a novel therapy strategy for poor prognosis acute myeloid leukemia

We present here strong preclinical data for a novel, mechanistically based, combinatorial approach to using DNA methyltransferase inhibitors (DNMTi’s), such as decitabine (DAC) and 5-Azacytidine (AzaC), with PARP inhibitors (PARPi’s) as a treatment strategy for acute myelogenous leukemias (AML). AzaC and DAC alone show efficacy in AML but combinatorial approaches will be required to maximize therapeutic responses. PARPi's have not been well studied as agents for these diseases. The mechanistic rationale for our approach is based upon: 1) data from our group and others showing DNMT's and PARP co-reside in DNA damage induced protein complexes; 2) the fact that AzaC and DAC trap DNMT's into DNA via their mechanism of action, led us to hypothesize that these drugs might also increase PARP trapping at DNA damage sites 3) the cytotoxicity of clinically available PARPi’s, and especially the most potent ones, appears to correlate with degree of trapping of PARP1 at DNA damage sites in chromatin. We first find that, indeed, in cultured human AML cells, the DNMTi's (10 to 20 nM DAC) and PARPi's (1 to 10 nM BMN 673) alone trap PARP into chromatin and this effect is enhanced when the drugs are combined. Concomitant with this, the combined doses, especially, strongly reduce double strand break (DSB) repair thereby increasing cytotoxic DNA damage. In association with these findings, in methylcellulose cloning assays of both cultured (N = 4) and primary AML cells (N = 9), a combination of the DNMTi's and PARPi's strongly decreased colony survival compared to each of the agents alone. Interestingly those cell lines and primary samples expressing poor prognostic FLT3/ITD (Fms-like tyrosine kinase 3 internal tandem duplication) mutations, were particularly sensitive to the combination treatment. Based on all the above results, we developed an in-vivo treatment model, using human FLT3/ITD-positive, MV411-luc xenografts in immunocompromised mice. As opposed to mock treatment, and treatment with AzaC or BMN673, alone, the combined drug treatment, over a 40 day treatment course, starkly and significantly decreases leukemia burden, as measured by luciferase imaging, peripheral blood blast counts and spleen weights. Our data suggest a novel use of both DNMTi's and PARPi's in a compelling therapeutic strategy for poor prognosis AML, that will be funded by Van Andel-SU2C for a clinical trial to be based at the University of Maryland.

Citation Format: Nidal E. Muvarak, Carine Robert, Pratik K. Nagaria, Khadiza Chowdhury, Eun Yong Choi, Vu Duong, Ashkan Emadi, Maria R. Baer, Rena Lapidus, Stephen Baylin, Feyruz Rassool. Combination of DNA methyltransferase and PARP inhibitors as a novel therapy strategy for poor prognosis acute myeloid leukemia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2848. doi:10.1158/1538-7445.AM2015-2848

Pharmacogenomic modeling of circulating tumor and invasive cells for prediction of chemotherapy response and resistance in pancreatic cancer

PURPOSE

Despite a challenging prognosis, modern cytotoxic therapy can induce tumor responses and extend life in pancreatic adenocarcinoma (PDAC). Pharmacogenomic (PGx) modeling of tumor tissue can predict the efficacy of chemotherapeutic agents in preclinical cancer models. We hypothesized that PGx profiling of circulating tumor and invasive cells (CTIC) isolated from peripheral blood could predict tumor response, progression, and resistance.

EXPERIMENTAL DESIGN

A PGx model was created and validated in preclinical models. A prospective clinical trial was conducted. Fifty patients with advanced PDAC were enrolled. Before treatment, 10 mL of peripherally drawn blood was collected. CTICs isolated from this blood sample were expression profiled and the PGx model was used to predict effective and ineffective chemotherapeutic agents. The treating physicians were blinded to PGx prediction.

RESULTS

We found that CTICs could be reliably isolated, total RNA extracted and profiled from 10 mL of peripheral blood from patients with unresectable PDAC before chemotherapy treatment and at disease progression. Using previously created PGx models to predict chemotherapy sensitivity, we found that clinical benefit was seen for study participants treated with chemotherapy regimens predicted to be effective versus chemotherapy regimens predicted to be ineffective with regard to progression-free (10.4 mo vs. 3.6 mo; P < 0.0001; HR, 0.14) and overall survival (17.2 mo vs. 8.3 mo; P < 0.0249; HR, 0.29).

CONCLUSIONS

These findings suggest that PGx profiling of CTICs can predict treatment response.

A pilot study of acupuncture in treating bortezomib-induced peripheral neuropathy in patients with multiple myeloma

BACKGROUND

Peripheral neuropathy is the dose limiting toxicity of bortezomib in patients with multiple myeloma (MM).

OBJECTIVES

To examine the safety, feasibility and efficacy of acupuncture in reducing bortezomib-induced peripheral neuropathy (BIPN) symptoms.

METHODS

Patients with MM experiencing persistent BIPN ≥grade 2 despite adequate medical intervention and discontinuation of bortezomib received 10 acupuncture treatments for 10 weeks (2×/week for 2 weeks, 1×/week for 4 weeks, and then biweekly for 4 weeks). Responses were assessed by the Clinical Total Neuropathy Score (TNSc), Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) questionnaire, and the Neuropathy Pain Scale (NPS). Repeated-measures analysis of variance was used to test for monotonic decline in scores on each of the measures. Serial serum levels of proinflammatory and neurotrophic cytokines were obtained at baseline and weeks 1, 2, 4, 8, and 14.

RESULTS

Twenty-seven patients with MM were enrolled in the trial. There were no adverse events associated with the acupuncture treatments. TNSc data were deemed invalid and therefore were not reported. At weeks 10 and 14, FACT/GOG-Ntx and NPS showed significant reduction suggesting decreased pain, and improved function (P values were <.0001 for both FACT/GOG-Ntx and NPS at weeks 10 and 14). However, nerve conduction studies did not significantly change between baseline assessment and end of study. There was no correlation in serum cytokines for responders versus none responders.

CONCLUSIONS

Acupuncture is safe, feasible and produces subjective improvements in patients' symptoms. A follow-up randomized controlled trial is warranted.

Translational phase I trial of vorinostat (suberoylanilide hydroxamic acid) combined with cytarabine and etoposide in patients with relapsed, refractory, or high-risk acute myeloid leukemia

PURPOSE

To determine the maximum-tolerated dose (MTD) of the histone deacetylase inhibitor vorinostat combined with fixed doses of cytarabine (ara-C or cytosine arabinoside) and etoposide in patients with poor-risk or advanced acute leukemia, to obtain preliminary efficacy data, describe pharmacokinetics, and in vivo pharmacodynamic effects of vorinostat in leukemia blasts.

EXPERIMENTAL DESIGN

In this open-label phase I study, vorinostat was given orally on days one to seven at three escalating dose levels: 200 mg twice a day, 200 mg three times a day, and 300 mg twice a day. On days 11 to 14, etoposide (100 mg/m(2)) and cytarabine (1 or 2 g/m(2) twice a day if ≥65 or <65 years old, respectively) were given. The study used a standard 3+3 dose escalation design.

RESULTS

Eighteen of 21 patients with acute myelogenous leukemia (AML) treated on study completed planned therapy. Dose-limiting toxicities [hyperbilirubinemia/septic death (1) and anorexia/fatigue (1)] were encountered at the 200 mg three times a day level; thus, the MTD was established to be vorinostat 200 mg twice a day. Of 21 patients enrolled, seven attained a complete remission (CR) or CR with incomplete platelet recovery, including six of 13 patients treated at the MTD. The median remission duration was seven months. No differences in percentage S-phase cells or multidrug resistance transporter (MDR1 or BCRP) expression or function were observed in vivo in leukemia blasts upon vorinostat treatment.

CONCLUSIONS

Vorinostat 200 mg twice a day can be given safely for seven days before treatment with cytarabine and etoposide. The relatively high CR rate seen at the MTD in this poor-risk group of patients with AML warrants further studies to confirm these findings.

Inhibition of poly(ADP-ribose) polymerase prevents irinotecan-induced intestinal damage and enhances irinotecan/temozolomide efficacy against colon carcinoma

Poly(ADP-ribose) polymerase (PARP) inhibitors enhance the antitumor activity of the topoisomerase I inhibitor irinotecan (CPT-11), which is used to treat advanced colorectal carcinoma. Since PARP inhibitors sensitize tumor cells also to the methylating agent temozolomide (TMZ) and clinical trials are evaluating CPT-11 in combination with TMZ, we tested whether the PARP inhibitor GPI 15427 (10-(4-methyl-piperazin-1-ylmethyl)-2H-7-oxa-1,2-diaza-benzo[de]anthracen-3-one) increases the efficacy of CPT-11 + TMZ against colon cancer. Moreover, due to the ability of PARP inhibitors to avoid cell death consequent to PARP-1 overactivation, we evaluated whether oral administration of GPI 15427 provides protection from the dose-limiting intestinal toxicity of CPT-11. The results of colony formation assay indicated that GPI 15427 increased the antiproliferative effects (combination index <1) of TMZ + SN-38 (the active metabolite of CPT-11) against colon cancer cells. Accordingly, GPI 15427 (40 mg/kg/dayx5 days per os) in combination with TMZ (10 mg/kg/dayx5 days) + CPT-11 (4 mg/kg/dayx5 days) significantly reduced the growth of tumor xenografts. Oral administration of GPI 15427 (40 mg/kg/q2x3 days) prevented intestinal injury and diarrhea induced by CPT-11 (30 mg/kg/day x 3 days) reducing inflammation and PARP-1 overactivation, as evidenced by immunohistochemical staining of intestinal tissue with antipoly(ADP-ribose) antibody (Ab). In conclusion, the PARP inhibitor represents a novel strategy to enhance the antitumor efficacy and reduce toxicity of chemotherapy in colon cancer.

High-affinity Near-infrared Fluorescent Small-molecule Contrast Agents for In Vivo Imaging of Prostate-specific Membrane Antigen

Surgical resection remains a definitive treatment for prostate cancer. Yet, prostate cancer surgery is performed without image guidance for tumor margin, extension beyond the capsule and lymph node positivity, and without verification of other occult metastases in the surgical field. Recently, several imaging systems have been described that exploit near-infrared (NIR) fluorescent light for sensitive, real-time detection of disease pathology intraoperatively. In this study, we describe a high-affinity (9 nM), single nucleophile-containing, small molecule specific for the active site of the enzyme PSMA. We demonstrate production of a tetra-sulfonated heptamethine indocyanine NIR fluorescent derivative of this molecule using a high-yield LC/MS purification strategy. Interestingly, NIR fluorophore conjugation improves affinity over 20-fold, and we provide mechanistic insight into this observation. We describe the preparative production of enzymatically active PSMA using a baculovirus expression system and an adenovirus that co-expresses PSMA and GFP. We demonstrate sensitive and specific in vitro imaging of endogenous and ectopically expressed PSMA in human cells and in vivo imaging of xenograft tumors. We also discuss chemical strategies for improving performance even further. Taken together, this study describes nearly complete preclinical development of an optically based small-molecule contrast agent for image-guided surgery.

Brain distribution and efficacy as chemosensitizer of an oral formulation of PARP-1 inhibitor GPI 15427 in experimental models of CNS tumors

We previously demonstrated that intravenous or intra-cerebral administration of poly (ADP-ribose) polymerase-1 (PARP-1) inhibitors increases the antitumor activity of temozolomide (TMZ), an oral anticancer drug used for the treatment of malignant melanoma and primary or secondary brain tumors. Since the oral route has a number of advantages in terms of safety and convenience with respect to intravenous injection, in this study we tested whether administration per os of the novel PARP-1 inhibitor GPI 15427 allows sufficient absorption of the compound and achievement of brain concentrations capable of enhancing the efficacy of TMZ against tumors growing at the CNS. Pharmacokinetics analysis of GPI 15427 levels in plasma and brain was assessed in Sprague-Dawley rats after oral dosing, by liquid chromatography and tandem mass spectrometry. Antitumor activity of oral GPI 15427 in association with TMZ was evaluated in BD2F1 mice injected intracranially with B16 melanoma or L5178Y lymphoma. Pharmacokinetics studies revealed that GPI 15427 possesses a substantial oral bioavailability (plasma Cmax after a single dose of 40 mg/kg: 1041+/-516 ng/ml). Moreover, the brain levels and brain/plasma ratios of GPI 15427 (3.37 at 0.5 h and 3.19 at 1 h) indicated that the compound readily penetrates the blood-brain barrier. GPI 15427 (10 or 40 mg/kg/per os) was then administered for five days, 1 h before TMZ (100 mg/kg/i.p.), to tumor-bearing mice. The results indicated that GPI 15427+TMZ was well tolerated and significantly increased life-span of the animals with respect to TMZ. In conclusion, PARP-1 inhibitor GPI 15427 is efficacious as chemosensitizer for the treatment of tumors located at the CNS site when it is administered by oral route.

Improved daytime spirometric efficacy of tiotropium compared with salmeterol in patients with COPD

BACKGROUND

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommends long-acting bronchodilators as first-line maintenance treatment for patients with chronic obstructive pulmonary disease (COPD). A study was conducted comparing the long-acting anticholinergic tiotropium with the long-acting beta-agonist salmeterol to confirm the significant improvements in daytime bronchodilator efficacy seen with tiotropium in previous studies.

METHODS

Randomized, double-blind, double-dummy, parallel-group study, comparing daytime bronchodilator efficacy of tiotropium 18 mcg once daily with salmeterol 50 mcg twice daily in patients with COPD. Serial spirometry was performed over 12 h after 12 weeks of treatment. Co-primary endpoints were average (over 12 h) and peak FEV1 at 12 weeks.

RESULTS

653 patients were randomized (328 tiotropium, 325 salmeterol): mean age 64 years; 66% male; mean baseline FEV1 1.05 l (37.7% predicted). After 12 weeks, the average post-dose FEV1 over 12 h was significantly higher with tiotropium compared with salmeterol (167 vs. 130 mL, respectively, p=0.03), as was peak FEV1 (262 vs. 216 ml, respectively, p=0.01). The average FEV1 responses from 0-6 h and 6-12 h were higher in the tiotropium group compared with salmeterol (p<0.05). Peak and average FVC were significantly higher with tiotropium compared with salmeterol (p<0.01). Morning pre-dose FEV1 responses were not significantly different; however, tiotropium demonstrated a significantly higher pre-dose FVC than salmeterol (p<0.05).

CONCLUSION

Tiotropium demonstrated significantly greater post-dose improvements in spirometric parameters compared with salmeterol. These improvements were sustained over 12 h.

Brain distribution and efficacy as chemosensitizer of an oral formulation of PARP-1 inhibitor GPI 15427 in experimental models of CNS tumors

We previously demonstrated that intravenous or intra-cerebral administration of poly (ADP-ribose) polymerase-1 (PARP-1) inhibitors increases the antitumor activity of temozolomide (TMZ), an oral anticancer drug used for the treatment of malignant melanoma and primary or secondary brain tumors. Since the oral route has a number of advantages in terms of safety and convenience with respect to intravenous injection, in this study we tested whether administration per os of the novel PARP-1 inhibitor GPI 15427 allows sufficient absorption of the compound and achievement of brain concentrations capable of enhancing the efficacy of TMZ against tumors growing at the CNS. Pharmacokinetics analysis of GPI 15427 levels in plasma and brain was assessed in Sprague-Dawley rats after oral dosing, by liquid chromatography and tandem mass spectrometry. Antitumor activity of oral GPI 15427 in association with TMZ was evaluated in BD2F1 mice injected intracranially with B16 melanoma or L5178Y lymphoma. Pharmacokinetics studies revealed that GPI 15427 possesses a substantial oral bioavailability (plasma Cmax after a single dose of 40 mg/kg: 1041+/-516 ng/ml). Moreover, the brain levels and brain/plasma ratios of GPI 15427 (3.37 at 0.5 h and 3.19 at 1 h) indicated that the compound readily penetrates the blood-brain barrier. GPI 15427 (10 or 40 mg/kg/per os) was then administered for five days, 1 h before TMZ (100 mg/kg/i.p.), to tumor-bearing mice. The results indicated that GPI 15427+TMZ was well tolerated and significantly increased life-span of the animals with respect to TMZ. In conclusion, PARP-1 inhibitor GPI 15427 is efficacious as chemosensitizer for the treatment of tumors located at the CNS site when it is administered by oral route.

Stress may add bite to appetite in women: a laboratory study of stress-induced cortisol and eating behavior

To date, there are few known predictors of stress-induced eating. The purpose of this study was to identify whether physiological and psychological variables are related to eating after stress. Specifically, we hypothesized that high cortisol reactivity in response to stress may lead to eating after stress, given the relations between cortisol with both psychological stress and mechanisms affecting hunger. To test this, we exposed fifty-nine healthy pre-menopausal women to both a stress session and a control session on different days. High cortisol reactors consumed more calories on the stress day compared to low reactors, but ate similar amounts on the control day. In terms of taste preferences, high reactors ate significantly more sweet food across days. Increases in negative mood in response to the stressors were also significantly related to greater food consumption. These results suggest that psychophysiological response to stress may influence subsequent eating behavior. Over time, these alterations could impact both weight and health.

[The electroencephalogram in psychiatric patients]

270 consecutive electroencephalograms (EEGs) performed in a psychiatric hospital were reviewed. 194 (75%) were within normal limits but 66 (25%) showed diffuse generalized slowing. The contribution of the abnormal EEGs to diagnosis and treatment was evaluated by retrospective file review. In none of the cases with abnormal EEGs was there a relationship to diagnosis or treatment.

The reconstituted mitochondrial adenine nucleotide translocator: effects of lipid polymorphism

This study investigates the role of polymorphic or nonbilayer lipids in the function of an integral membrane protein which is a key component of the mitochondrial energy transduction apparatus. The adenine nucleotide translocator (AdNT) has been isolated from rat heart mitochondria and reconstituted into ATP-containing liposomes composed of dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylethanolamine (DOPE), and cardiolipin (CL). CL content was held constant at 11.1 mol%; the ratio of DOPC:DOPE was varied to manipulate R0, the intrinsic radius of curvature of the bilayer [S. M. Gruner (1985) Proc. Natl. Acad. Sci. USA 82, 3665-3669]. Translocator activity was determined fluorometrically, using a coupled enzyme system to measure ADP-induced efflux of ATP. Specific activity was calculated based on the number of functional translocators in each preparation, quantified using the tight-binding inhibitor carboxyatractylate (CAT). AdNT specific activity was a smooth function of R0, with a maximum at a lipid composition similar to that of the inner mitochondrial membrane. Protein incorporation was constant at DOPC:DOPE ratios > 1, but appeared to increase at ratios < or = 1. The fraction of reconstituted AdNT incorporated in the native mitochondrial orientation, estimated from inhibition by 10 microM CAT, was independent of lipid composition and > 85%. Leakage of encapsulated ATP increased at low R0 values both in the presence and absence of protein.

Use of carboxyatractylate and tight-binding inhibitor theory to determine the concentration of functional mitochondrial adenine nucleotide translocators in a reconstituted system

The adenine nucleotide translocator (AdNT) has been isolated from rat heart mitochondria and reconstituted into liposomes containing ATP. Translocator activity was determined using a coupled enzyme system to measure the ADP-induced efflux of ATP from the liposomes. In order to determine specific activity, the number of functional translocators must also be known. Carboxyatractylate (CAT) is a highly selective inhibitor of the AdNT, with Ki < 10 nM, a value sufficiently low relative to the concentration of protein in transport assays to suggest the use of tight-binding inhibitor theory to quantify functional translocators. Ackermann-Potter plots of velocity vs proteoliposome concentration at several different CAT concentrations were used both to demonstrate the occurrence of tight-binding inhibition and to determine the concentration of AdNT catalytic sites in the native orientation. The results obtained agreed well with earlier reports based on [14C]CAT binding; functionally reconstituted AdNT represented 5-10% of the protein added to the system. Specific activities were ca. 7-10 mumol/min mg depending on the lipid composition of the liposomes. Unincorporated protein did not appreciably affect the measurements. This methodology should be readily applicable to any reconstituted systems for which high-affinity inhibitors which bind only to active protein are known.