Novel compound C150 inhibits pancreatic cancer through induction of ER stress and proteosome assembly

Pancreatic cancer is a devastating disease with a dismal prognosis and poor treatment outcomes. Searching for new agents for pancreatic cancer treatment is of great significance. We previously identified a novel activity of compound C150 to inhibit pancreatic cancer epithelial-to-mesenchymal transition (EMT). Here, we further revealed its mechanism of action. C150 induced ER stress in pancreatic cancer cells and subsequently increased proteasome activity by enhancing proteasome assembly, which subsequently enhanced the degradation of critical EMT transcription factors (EMT-TFs). In addition, as cellular responses to ER stress, autophagy was elevated, and general protein synthesis was inhibited in pancreatic cancer cells. Besides EMT inhibition, the C150-induced ER stress resulted in G2/M cell cycle arrest, which halted cell proliferation and led to cellular senescence. In an orthotopic syngeneic mouse model, an oral dose of C150 at 150 mg/kg 3× weekly significantly increased survival of mice bearing pancreatic tumors, and reduced tumor growth and ascites occurrence. These results suggested that compound C150 holds promises in comprehensively inhibiting pancreatic cancer progression.

Abstract 1529: Role of bitter taste receptor in colon cancer

Colorectal cancer (CRC) is a leading cause of cancer-related deaths in the US with 53,200 deaths projected in 2020. Although the disease affects older people, recent statistics show an increase in the younger population. CRC is a major problem in veterans and every year ~4,000 veterans are diagnosed with CRC within VA facilities. Hence, there is a dire need to identify novel signaling pathways as targets for therapy. Based on a bedside discovery in CRC patients, we observed that CRC patients complained about dysgeusia or taste alterations. There are 25 bitter taste receptors (TAS2R1-50, TAS2R60). Taste receptors utilize G-protein coupled receptors (GPCRs) and signal through calcium release. In preliminary studies, mining the Cancer Genome Atlas (TCGA) database, we have determined that TAS2R38 is upregulated in multiple cancers, including CRC. Moreover, the higher expression of TAS2R38 transcript in CRC compared to other cancers. Furthermore, we confirmed overexpression of TAS2R38 in CRC tissues and cell lines by immunohistochemistry and RT-PCR. Moreover, N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL), a TAS2R38 agonist, treatment activated calcium mobilization in HCT116 and DLD1 cells suggesting the functionality of the receptor. OdDHL also enhanced mRNA of interleukin (IL)-6 and IL-8 levels in the CRC cells. To determine whether expression of the receptor is affected in vivo, we conducted the dextran sodium sulfate (DSS)-induced acute colitis and colitis-associated cancer model (azoxymethane (AOM)-DSS) in C57BL/6 mice. TAS2R138, the mouse homolog of human TAS2R38 is overexpressed in crypt epithelial cells in the colitis and tumor tissues. These observations suggest that TAS2R38 is overexpressed in the CRC and may play a critical role in disease progression.

Citation Format: Krishan Jain, Sangita Bhattacharyya, Afreen Sayed, David Standing, Kathy Benich, Shahid Umar, Shrikant Anant, Scott Weir, Roy Jansen, Prasad Ravindra Dandawate. Role of bitter taste receptor in colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1529.

Novel Compound C150 Inhibits Pancreatic Cancer Cell Epithelial-to-Mesenchymal Transition and Tumor Growth in Mice

Pancreatic cancer cell epithelial-to-mesenchymal transition (EMT) is an important contributor to cell invasion and tumor progression. Therefore, targeting EMT may be beneficial for pancreatic cancer treatment. The aim of the present study was to report on the inhibitory effect of the novel compound C150 on the EMT of pancreatic cancer cells. C150 inhibited cell proliferation in multiple pancreatic cancer cells with IC₅₀ values of 1-2.5 μM, while in an non-cancerous pancreatic epithelial cell line hTERT-HPNE the IC₅₀ value was >12.5 μM. C150 significantly inhibited pancreatic cancer cell migration and invasion, as demonstrated by 3-dimensional cell invasion, wound healing and Boyden chamber Transwell migration-invasion assays. Moreover, C150 treatment decreased MMP-2 gene expression in PANC-1 cells and reduced MMP-2 activity in gelatin zymography assay. In an orthotopic mouse model of pancreatic cancer, C150 significantly reduced tumor growth at the dose of 15 mg/kg by intraperitoneal injection three times per week. Furthermore, C150 enhanced protein degradation of Snail, an important EMT-promoting transcription factor, and decreased the expression of the mesenchymal marker N-cadherin, while it increased the expression of the epithelial markers zonula occludens-1 and claudin-1. The findings of the present study suggested that C150 is a novel EMT inhibitor that may be promising for inhibiting pancreatic cancer growth and metastasis.

Intra- and interspecific toxicity testing methods and data for nematodes exposed to metals

Twenty-four hour median lethal concentration (LC50) toxicity tests were performed with five species of nematodes (Caenorhabditis elegans, Caenorhabditis briggsae, Pristionchus pacificus, Oscheius tipulae, and Oscheius myriophila) in response to copper chloride and zinc chloride. In addition, lethality tests were also performed with seven strains of C. elegans (N2 > 1 year in culture, N2 newly acquired, N2 ancestral, ED3053, JU258, JU1171, and MY1) exposed to copper chloride. Nominal chemical concentrations were validated and analyzed according to U.S. Environmental Protection Agency method 6010 using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). This paper combines the datasets previously published separately by Heaton et al. (2020, 2022). The goal is to catalog all raw and analyzed toxicity data collected from both studies in a single consistent information source for use by the scientific community.

Disrupting interferon-alpha and NF-kappaB crosstalk suppresses IFITM1 expression attenuating triple-negative breast cancer progression

Overexpression of interferon induced transmembrane protein-1 (IFITM1) enhances tumor progression in multiple cancers, but its role in triple-negative breast cancer (TNBC) is unknown. Here, we explore the functional significance and regulation of IFITM1 in TNBC and strategies to target its expression. Immunohistochemistry staining of a tissue microarray demonstrates that IFITM1 is overexpressed in TNBC samples which is confirmed by TCGA analysis. Targeting IFITM1 by siRNA or CRISPR/Cas9 in TNBC cell lines significantly inhibits proliferation, colony formation, and wound healing in vitro. Orthotopic mammary fat pad and mammary intraductal studies reveal that loss of IFITM1 reduces TNBC tumor growth and invasion in vivo. RNA-seq analysis of IFITM1/KO cells reveals significant downregulation of several genes involved in proliferation, migration, and invasion and functional studies identified NF-κB as an important downstream target of IFITM1. Notably, siRNA knockdown of p65 reduces IFITM1 expression and a drug-repurposing screen of FDA approved compounds identified parthenolide, an NFκB inhibitor, as a cytotoxic agent for TNBC and an inhibitor of IFITM1 in vitro and in vivo. Overall, our findings suggest that targeting IFITM1 by suppressing interferon-alpha/NFκB signaling represents a novel therapeutic strategy for TNBC treatment.

A Phase I Study to Evaluate Two Doses of Wharton's Jelly-Derived Mesenchymal Stromal Cells for the Treatment of De Novo High-Risk or Steroid-Refractory Acute Graft Versus Host Disease

BACKGROUND

Because of their well-described immunosuppressive properties, allogeneic adult human mesenchymal stromal cells (MSC) derived from bone marrow have demonstrated safety and efficacy in steroid refractory acute graft versus host disease (SR aGVHD). Clinical trials have resulted in variable success and an optimal source of MSC has yet to be defined. Based on the importance of maternal-fetal interface immune tolerance, extraembryonic fetal tissues, such as the umbilical cord, may provide an superior tissue source of MSC to mediate immunomodulation in aGVHD.

METHODS

A two-dose cohort trial allogeneic Wharton's Jelly-derived mesenchymal stromal cells (WJMSC, referred to as MSCTC-0010, here) were tested in 10 patients with de novo high risk (HR) or SR aGVHD post allogeneic hematopoietic stem cell transplantation (allo-HCT). Following Good Manufacturing Practices isolation, expansion and cryostorage, WJMSC were thawed and administered via intravenous infusions on days 0 and 7 at one of two doses (low dose cohort, 2 × 10⁶/kg, n = 5; high dose cohort, 10 × 10⁶/kg, n = 5). To evaluate safety, patients were monitored for infusion related toxicity, Treatment Related Adverse Events (TRAE) til day 42, or ectopic tissue formation at day 90. Clinical responses were monitored at time points up to 180 days post infusion. Serum biomarkers ST2 and REG3α were acquired 1 day prior to first MSCTC-0010 infusion and on day 14.

RESULTS

Safety was indicated, e.g., no infusion-related toxicity, no development of TRAE, nor ectopic tissue formation in either low or high dose cohort was observed. Clinical response was suggested at day 28: the overall response rate (ORR) was 70%, 4 of 10 patients had a complete response (CR) and 3 had a partial response (PR). By study day 90, the addition of escalated immunosuppressive therapy was necessary in 2 of 9 surviving patients. Day 100 and 180 post infusion survival was 90% and 60%, respectively. Serum biomarker REG3α decreased, particularly in the high dose cohort, and with REG3α decrease correlated with clinical response.

CONCLUSIONS

Treatment of patients with de novo HR or SR aGVHD with low or high dose MSCTC-0010 was safe: the infusion was well-tolerated, and no TRAEs or ectopic tissue formation was observed. A clinical improvement was seen in about 70% patients, with 4 of 10 showing a complete response that may have been attributable to MSCTC-0010 infusions. These observations indicate safety of two different doses of MSCTC-0010, and suggest that the 10 × 10⁶ cells/ kg dose be tested in an expanded randomized, controlled Phase 2 trial. Graphical abstract.

CCN5 activation by free or encapsulated EGCG is required to render triple-negative breast cancer cell viability and tumor progression

Epigallocatechin-3-gallate (EGCG) has been considered an anticancer agent despite conflicting and discrepant bioavailability views. EGCG impairs the viability and self-renewal capacity of triple-negative breast cancer (TNBC) cells and makes them sensitive to estrogen via activating ER-α. Surprisingly, the mechanism of EGCG's action on TNBC cells remains unclear. CCN5/WISP-2 is a gatekeeper gene that regulates viability, ER-α, and stemness in TNBC and other types of cancers. This study aimed to investigate whether EGCG (free or encapsulated in nanoparticles) interacts with the CCN5 protein by emphasizing its bioavailability and enhancing its anticancer effect. We demonstrate that EGCG activates CCN5 to inhibit in vitro cell viability through apoptosis, the sphere-forming ability via reversing TNBC cells' stemness, and suppressing tumor growth in vivo. Moreover, we found EGCG-loaded nanoparticles to be functionally more active and superior in their tumor-suppressing ability than free-EGCG. Together, these studies identify EGCG (free or encapsulated) as a novel activator of CCN5 in TNBC cells and hold promise as a future therapeutic option for TNBC with upregulated CCN5 expression.

Synthesis, antibiotic structure-activity relationships, and cellulose dissolution studies of new room-temperature ionic liquids derived from lignin

BACKGROUND

Ionic liquids (ILs) are promising pretreatment solvents for lignocellulosic biomass, but are largely prepared from petroleum precursors. Benzaldehydes from depolymerized lignin, such as vanillin, syringaldehyde, and 4-methoxy benzaldehyde, represent renewable feedstocks for the synthesis of ionic liquids. We herein report syntheses of novel lignin-derived ionic liquids, with extended N-alkyl chains, and examine their melting points, cellulose dissolution capacities, and toxicity profiles against Daphnia magna and E. coli strain 1A1. The latter organism has been engineered to produce isoprenol, a drop-in biofuel and precursor for commodity chemicals.

RESULTS

The new N,N-diethyl and N,N-dipropyl methyl benzylammonium ILs were liquids at room temperature, showing 75-100 °C decreased melting points as compared to their N,N,N-trimethyl benzylammonium analog. Extension of N-alkyl chains also increased antibacterial activity threefold, while ionic liquids prepared from vanillin showed 2- to 4-fold lower toxicity as compared to those prepared from syringaldehyde and 4-methoxybenzaldehyde. The trend of antibacterial activity for anions of lignin-derived ILs was found to be methanesulfonate < acetate < hydroxide. Microcrystalline cellulose dissolution, from 2 to 4 wt% after 20 min at 100 °C, was observed in all new ILs using light microscopy and IR spectroscopy.

CONCLUSIONS

Ionic liquids prepared from H-, S- and G-lignin oxidation products provided differential cytotoxic activity against E. coli and D. magna, suggesting these compounds could be tailored for application specificity within a biorefinery.

SAT0216 DISEASE SEVERITY, COMORBID CONDITIONS, TREATMENT PATTERNS, AND FLARES IN ADULTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS IN THE UNITED KINGDOM: A REAL-WORLD OBSERVATIONAL RETROSPECTIVE COHORT ANALYSIS

Background:

There is limited real-world evidence describing the presentation and treatment patterns of systemic lupus erythematosus (SLE) in the United Kingdom (UK).

Objectives:

To characterize disease severity, comorbid conditions, treatment patterns, and flares in a longitudinal cohort of adults with SLE in the UK.

Methods:

Patients aged ≥18 years with SLE were identified in the Clinical Practice Research Datalink – Hospital Episode Statistics database from January 1, 2005, to December 31, 2017. Patients were required to have ≥12 months of data before and after index date (date of earliest SLE diagnosis available). SLE disease severity and flares were classified as mild, moderate, or severe using adapted claims-based algorithms1,2that use SLE-related conditions (eg, end-stage renal disease), medications (eg, antimalarials, immunosuppressants, and corticosteroids), and health service use (eg, hospitalizations and emergency department visits).

Results:

Of 802 patients with SLE, 369 (46.0%) had mild, 345 (43.0%) had moderate, and 88 (11.0%) had severe SLE at baseline. In total, 692 (86.3%) patients were treated with SLE medications in the first year after SLE diagnosis. Among the total population (802), 557 (69.5%) patients received antimalarials, 203 (25.3%) received immunosuppressants, and 416 (51.9%) received corticosteroids (prednisolone); patients may have received ≥1 type of drug. Information on biologic use in hospitals is unavailable in these data. The mean (standard deviation [SD]) time to initiating any medication from index date was 177 (385.3) days (Figure 1A). The median time to first flare from index date was 63 days (95% confidence interval 57–71) (Figure 1B). A majority of patients (750/802, 93.5%) experienced ≥1 flare during follow-up; the first flare was mild for 73.2% of patients (549/750), moderate for 15.5% (116/750), and severe for 11.3% (85/750). The mean (SD) annual overall flare rate in the first year after index date was 3.5 (2.5) (mild flares: 2.6 [2.5]; moderate flares: 0.7 [1.5]; severe flares: 0.2 [0.6]) (Figure 2). A shorter median time to first flare was significantly associated with moderate or severe disease (P<0.001) and the presence of comorbid conditions (P<0.001).

Conclusion:

Our findings suggest some delay in SLE treatment initiation in the UK. Most patients with SLE experience flares within 2 months from diagnosis. Early treatment may delay or reduce the severity of the first SLE flare after diagnosis and may translate to slower disease progression, lower organ damage accrual, and better outcomes.

References:

[1]Garris C, et al.J Med Econ. 2013;16:667–77.

[2]Nightingale AL, et al.Lupus Sci Med. 2017;4:e000172.

Disclosure of Interests:

Julia Langham Consultant of: AstraZeneca, Volkan Barut Employee of: AstraZeneca, Mihail Samnaliev Consultant of: AstraZeneca, Sue Langham Consultant of: AstraZeneca, Sharada Weir Consultant of: AstraZeneca, Xia Wang Employee of: AstraZeneca, Barnabas Desta Employee of: AstraZeneca, Edward R. Hammond Employee of: AstraZeneca

THU0550 HEALTH CARE UTILIZATION AND COSTS IN ADULTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS IN THE UNITED KINGDOM: A REAL-WORLD OBSERVATIONAL RETROSPECTIVE COHORT STUDY

Background:

There is limited real-world evidence demonstrating the long-term direct costs associated with systemic lupus erythematosus (SLE) in the United Kingdom (UK).

Objectives:

To describe health care resource utilization and costs in adults with SLE in the UK over time and document costs by disease severity and type of encounter, including primary care, hospitalizations, outpatient visits, and prescription drugs.

Methods:

Patients aged ≥18 years with SLE were identified in the linked Clinical Practice Research Datalink – Hospital Episode Statistics database from January 1, 2005, to December 31, 2017. Patients were required to have data from ≥12 months before and after the index date, defined as the date of earliest diagnosis available in the data set. Patients were classified as having mild, moderate, or severe disease using an adapted claims-based algorithm.1Costs were calculated in 2017 UK pounds from the UK national health care system perspective. We estimated all-cause health care costs and incremental costs associated with each year of follow-up compared with a baseline year (3 years before index) using each patient as his or her own control and adjusting for age, sex, disease severity, and comorbid conditions.

Results:

Of the 802 patients identified, 369 (46.0%) had mild SLE, 345 (43.0%) had moderate SLE, and 88 (11.0%) had severe SLE. The mean all-cause cost increased in the 3 years before diagnosis and, in the first year after diagnosis, amounted to £7532 (standard deviation [SD] £9634). This cost varied by disease severity: mild SLE, £5221 (£8064); moderate SLE, £8323 (£9846); and severe SLE, £14,125 (£11,267) (Figure 1). Adjusted total mean annual increase in costs per patient in the overall study population was £4476 (95% confidence interval £3809–5143) greater in the year of diagnosis compared with the baseline year (P<0.0001), adjusted for age, sex, disease severity, and comorbid conditions. Primary care utilization was the leading component of costs during the first year after diagnosis, followed by prescriptions, outpatient care, and inpatient care (Figure 2). Information on biologic use in hospitals is unavailable in these data.

Conclusion:

The direct costs of health care for patients with SLE in the UK are substantial and persist over the years after diagnosis. Patients with moderate or severe SLE have higher all-cause costs over time compared with patients with mild SLE. Earlier diagnosis and treatment may reduce disease severity and occurrence of comorbidities, and the associated high health care costs.

References:

[1]Garris C, et al.J Med Econ. 2013;16:667–677.

[2]Department of Health. NHS reference costs 2017/18.https://improvement.nhs.uk/resources/reference-costs/#rc1718;2018 [accessed May 11, 2019].

Disclosure of Interests:

Mihail Samnaliev Consultant of: AstraZeneca, Volkan Barut Employee of: AstraZeneca, Sharada Weir Consultant of: AstraZeneca, Julia Langham Consultant of: AstraZeneca, Sue Langham Consultant of: AstraZeneca, Xia Wang Employee of: AstraZeneca, Barnabas Desta Employee of: AstraZeneca, Edward R. Hammond Employee of: AstraZeneca

Patient deprivation and perceived scan burden negatively impact the quality of whole-body MRI

AIM

To evaluate the association between the image quality of cancer staging whole-body magnetic resonance imaging (WB-MRI) and patient demographics, distress, and perceived scan burden.

MATERIALS AND METHODS

A sample of patients recruited prospectively to multicentre trials comparing WB-MRI with standard scans for staging lung and colorectal cancer were invited to complete two questionnaires. The baseline questionnaire, administered at recruitment, collated data on demographics, distress and co-morbidity. The follow-up questionnaire, completed after staging investigations, measured perceived WB-MRI scan burden (scored 1 low to 7 high). WB-MRI anatomical coverage, and technical quality was graded by a radiographic technician and grading combined to categorise the scan as "optimal", "sub-optimal" or "degraded". A radiologist categorised 30 scans to test interobserver agreement. Data were analysed using the chi-square, Fisher's exact, t-tests, and multinomial regression.

RESULTS

One hundred and fourteen patients were included in the study (53 lung, 61 colorectal; average age 65.3 years, SD=11.8; 66 men [57.9%]). Overall, 45.6% (n=52), scans were classified as "optimal" quality, 39.5% (n=45) "sub-optimal", and 14.9% (n=17) as "degraded". In adjusted analyses, greater deprivation level and higher patient-reported scan burden were both associated with a higher likelihood of having a sub-optimal versus an optimal scan (odds ratio [OR]: 4.465, 95% confidence interval [CI]: 1.454 to 13.709, p=0.009; OR: 1.987, CI: 1.153 to 3.425, p=0.013, respectively). None of the variables predicted the likelihood of having a degraded scan.

CONCLUSIONS

Deprivation and patients' perceived experience of the WB-MRI are related to image quality. Tailored protocols and individualised patient management before and during WB-MRI may improve image quality.

The Histone Demethylase KDM3A, Increased in Human Pancreatic Tumors, Regulates Expression of DCLK1 and Promotes Tumorigenesis in Mice

BACKGROUND & AIMS

The histone lysine demethylase 3A (KDM3A) demethylates H3K9me1 and H3K9Me2 to increase gene transcription and is upregulated in tumors, including pancreatic tumors. We investigated its activities in pancreatic cancer cell lines and its regulation of the gene encoding doublecortin calmodulin-like kinase 1 (DCLK1), a marker of cancer stem cells.

METHODS

We knocked down KDM3A in MiaPaCa-2 and S2-007 pancreatic cancer cell lines and overexpressed KDM3A in HPNE cells (human noncancerous pancreatic ductal cell line); we evaluated cell migration, invasion, and spheroid formation under hypoxic and normoxic conditions. Nude mice were given orthotopic injections of S2-007 cells, with or without (control) knockdown of KDM3A, and HPNE cells, with or without (control) overexpression of KDM3A; tumor growth was assessed. We analyzed pancreatic tumor tissues from mice and pancreatic cancer cell lines by immunohistochemistry and immunoblotting. We performed RNA-sequencing analysis of MiaPaCa-2 and S2-007 cells with knockdown of KDM3A and evaluated localization of DCLK1 and KDM3A by immunofluorescence. We analyzed the cancer genome atlas for levels of KDM3A and DCLK1 messenger RNA in human pancreatic ductal adenocarcinoma (PDAC) tissues and association with patient survival time.

RESULTS

Levels of KDM3A were increased in human pancreatic tumor tissues and cell lines, compared with adjacent nontumor pancreatic tissues, such as islet and acinar cells. Knockdown of KDM3A in S2-007 cells significantly reduced colony formation, invasion, migration, and spheroid formation, compared with control cells, and slowed growth of orthotopic tumors in mice. We identified KDM3A-binding sites in the DCLK1 promoter; S2-007 cells with knockdown of KDM3A had reduced levels of DCLK1. HPNE cells that overexpressed KDM3A formed foci and spheres in culture and formed tumors and metastases in mice, whereas control HPNE cells did not. Hypoxia induced sphere formation and increased levels of KDM3A in S2-007 cells and in HPNE cells that overexpressed DCLK1, but not control HPNE cells. Levels of KDM3A and DCLK1 messenger RNA were higher in human PDAC than nontumor pancreatic tissues and correlated with shorter survival times of patients.

CONCLUSIONS

We found human PDAC samples and pancreatic cancer cell lines to overexpress KDM3A. KDM3A increases expression of DCLK1, and levels of both proteins are increased in human PDAC samples. Knockdown of KDM3A in pancreatic cancer cell lines reduced their invasive and sphere-forming activities in culture and formation of orthotopic tumors in mice. Hypoxia increased expression of KDM3A in pancreatic cancer cells. Strategies to disrupt this pathway might be developed for treatment of pancreatic cancer.

Abstract 4398: KDM3A and DCLK1 interactions promote stemness and tumorigenesis in PDAC

Pancreatic ductal adenocarcinoma (PDAC) is the major leading cause of cancer related human death in USA. There is no possible treatment or target available in PDAC. It was proposed that the cancer stem cells (CSCs) can regulates malignancy in PDAC. DCLK1 is one of the quiescent cancer stem cell marker in PDAC that can regulate tumor progression. Identification of the key factors that influence stemness will help to target PDAC. Histone lysine demethylase KDM3A is an enzyme/protein which can regulate stem cell renewability and tumor progression, thereby KDM3A can interact with DCLK1 for tumor progression. KDM3A influences tumor growth and regulates stemness. Therefore, our goal is to find out the the role of KDM3A in tumor progression in PDAC through interactions with DCLK1. We observed expression of KDM3A in both PDAC patients’ samples and cells. Knockdown and overexpression of KDM3A were executed by using lentiviral vector. Tumor progression were also observed in orthotopic mice model. ChIP and RNA seq were performed to validate the data. KDM3A was overexpressed in human PDAC patient tissues and human pancreatic cancer cells with concomitant increase of CSC marker, DCLK1. Moreover, DCLK1 and KDM3A was found to be co-localized in patient tissue samples and identified binding sites of KDM3A with DCLK1 using ChIP-seq. Knockdown of KDM3A abrogates oncogenic potential whereas, overexpressed KDM3A in transformed HPNE cells showed malignant properties with enhanced invasive property, pancosphere formation, foci formation and tumor formation in mouse. Moreover, ChIP-seq and RNA seq suggested that KDM3A regulated DCLK1 expression in tumor progression. In conclusion, co-expression of DCLK1 with KDM3A influenced stemness and enhance tumor progression in PDAC.

Citation Format: Chandrayee Ghosh, Kankaraj Palaniyandi, Santanu Paul, Prasad Dandawate, Sonia Rawal, Dharmalingam Subramaniam, Subhash Padhye, Sumedha Gunewardena, Sufi Thomas, Maura O'Neil, Roy Jensen, Danny Welch, Sally Milisky, Scott Weir, Tomoo Iwakuma, Shrikant Anant, Animesh Dhar. KDM3A and DCLK1 interactions promote stemness and tumorigenesis in PDAC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4398.

Abstract CT103: Low-dose daunorubicin to target leukemia stem cells in newly diagnosed and relapsed/refractory AML

Background: Chemotherapy-resistant leukemia stem cells (LSC) are responsible for disease relapse in many patients with Acute Myeloid Leukemia (AML). The Wnt/β-catenin and PI3K/Akt pathways are frequently activated in cancer and interact to stimulate stem cell expansion through phosphorylation of β-catenin by Akt (pS552-β-catenin). We hypothesize that targeting pS552-β-catenin may inhibit chemoresistant LSCs. High-throughput screening identified that anthracyclines doxorubicin (DXR) and daunorubicin (DNR) inhibit Akt:β-catenin interaction at significantly lower doses than conventionally used. Using a mouse leukemia model, we repurposed DXR as a targeted therapy for pS552-β-catenin inhibition rather than a broadly cytotoxic agent. In contrast to the typical dose, which may stimulate expansion of resistant LSC, targeted/low-dose DXR inhibited chemoresistant LSC expansion and significantly reduced LSC tumorigenic potential. AML patients typically receive high-dose DNR but often relapse due to persistence of therapy-resistant LSCs, which frequently express pS552-β-catenin. Here, we use a metronomic approach to test the ability of low-dose anthracycline therapy to target therapy-resistant LSCs.

Methods: A proof of concept trial (NCT02914977) was designed to measure the ability of low dose DNR to inhibit pS552-β-catenin in LSCs of adult relapsed/refractory AML patients. A protocol amendment added a second cohort of patients with newly diagnosed AML undergoing standard chemotherapy with DNR and cytarabine (7+3 induction). Treatment in each cohort consisted of DNR given at a dose of 6.75mg/m2/day x 5 days. Patients with relapsed/refractory AML had bone marrow aspiration pre-treatment prior to day 1, followed by DNR on days 1-5, and a post-treatment bone marrow aspiration on day 8. Patients with newly diagnosed AML were treated with conventional 7+3 chemotherapy. A sample from the day 14 bone marrow was collected. DNR was given on days 15-19. Bone marrow aspiration was performed with blood count recovery and samples sent for LSC marker assessment. In this study, we will determine the safety, pharmacokinetics, and pharmacodynamic effects of low dose DNR. The LSC population and phosphorylation status of β-catenin will be measured pre- and post-treatment. Two or more prior induction attempts are required for study entry for refractory patients; relapsed patients require only one prior induction. The trial has enrolled 14 patients: 11 in the relapsed cohort and 3 in the newly diagnosed cohort. A total of 18 patients are planned.

In this pilot proof of concept trial, we will demonstrate the feasibility of serial bone marrow aspiration to measure biomarkers of LSC response. This clinical proof of concept trial design with serial bone marrow aspirations may also be used to rapidly assess the validity of other LSC markers and targeted agents.

Citation Format: Tara L. Lin, John M. Perry, Xi He, Gregory Reed, Na Zhang, Scott Weir, Joseph McGuirk, Linheng Li. Low-dose daunorubicin to target leukemia stem cells in newly diagnosed and relapsed/refractory AML [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT103.

Abstract B03: Targeting the KIF11/KIF15/TPX2 axis to develop new therapies for ovarian cancer

Unlimited genetic and epigenetic diversity across the patient population, and within the tumor and among metastatic lesions of an individual patient, presents a challenge in developing targeted therapies to treat epithelial ovarian cancer (EOC). To find the Achilles heel of ovarian cancers, we designed an RNAi-based screen (&gt;6,000 genes) to identify points of molecular vulnerability. These screens identified KIF11 as essential to maintain tumor cell viability. KIF11 encodes kinesin Eg5 (KIF11), a motor protein required for microtubule antiparallel sliding during mitosis that has been targeted clinically. Although KIF11 inhibitors are well tolerated by EOC patients, clinical response rates were disappointing in heavily treated patients with advanced disease. We hypothesize one mechanism through which KIF11 inhibitors’ efficacy is muted is via functional compensation of mitotic spindle assembly by KIF15, a second motor kinesin. Using a synthetic lethal approach, we have shown that RNAi-mediated silencing of KIF15 has no effect on cell viability, but significantly sensitized cells by &gt;10- to 100-fold to a class of KIF11 inhibitors (KIF11is). TPX2-targeted siRNAs reduce cell viability by 5-fold alone, and sensitize cells by 100-fold in the presence of KIF11i. Based on these observations, we designed a high-throughput screening assay using Alpha Technology©. Informed by previous predictions of KIF15-TPX2 binding domains, we designed peptides corresponding to the appropriate domains of KIF15 (aa1149-1388, GST-tagged) and TPX2 (aa346-747, His-tagged), for use in the AlphaScreen© assay. Following several optimization steps (e.g., buffer selection, protein titration, TruHits© assay validation), we demonstrate that KIF15 binds TPX2, producing a signal &gt;30-fold greater than background signal. Further, peptides designed to mimic either KIF15 or TPX2 binding domains, but not scrambled controls, exhibited concentration-dependent disruption of the KIF15-TPX2 interaction. Next, we screened a FDA library (3,474 compounds) and bioactive (1,902 compounds) library and identified 122 hits; fresh compound stocks were tested at 4 concentrations (20, 10, 5, and 2.5 μM), resulting in 53 confirmed hits (28 FDA, 25 bioactive). To identify false positives that interfere with assay chemistry, we repeated the screen at 3 concentrations, replacing the His-TPX2 and GST-KIF15 proteins with a His-GST fusion. As an orthogonal screen, we performed a Homogenous Time Resolved Fluorescence© (HTRF)-based screen to reconfirm hit compounds at the aforementioned concentrations. From these combined data, we have identified 4 hit compounds (KU-P001 to KU-P004) that disrupt KIF15/TPX2 protein-protein interactions. To further prioritize our hits, we developed in vitro (EOC cell lines were exposed to increasing concentrations, up to 1 µM, of KIF11i for 4 months) and in vivo (patient-derived ascites xenograft models of EOC were treated with 3 cycles of either 5 mg/kg or 10 mg/kg of a KIF11i and were serially passaged and treated for 3 additional generations) models of KIF11i-resistance to evaluate their activities. In resistant EOC cells we observed a 3-fold increase in KIF15 protein expression as compared with parental cells; TPX2 protein expression remained unchanged. In vivo, both KIF15 (68% increase) and TPX2 (2-fold) protein expression was increased in resistant versus untreated PDX tumor cells. Combination studies of KU-P004 and ispinesib (KIF11i) in vitro revealed a 2- to 64-fold increase in cell death for both responsive and resistant EOC cells compared with KIF11i treatment alone. In summary, we have developed a high-throughput screening assay platform to identify inhibitors of the KIF15-TPX2 interaction and are using iterative medicinal chemistry to guide optimization and functional evaluation of hits and lead compounds to develop new combination therapies for women with ovarian cancer.

Citation Format: Rebecca J. Wates, Anuradha Roy, Frank Schoenen, John Karanicolas, Scott Weir, Andrew Godwin. Targeting the KIF11/KIF15/TPX2 axis to develop new therapies for ovarian cancer. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr B03.

Abstract CT137: Biomarkers of response to leukemia stem cell targeted therapy with low dose daunorubicin in relapsed/refractory acute leukemia

Patients with acute leukemia harbor chemotherapy-resistant leukemia stem cells (LSC) which ultimately lead to disease relapse in many patients. Clinical trial design of LSC targeted therapy is a challenge. The majority of leukemia cells are differentiated leukemia cells, with LSC comprising &lt;1%. Clinical benefit of LSC targeted therapy is best measured by overall survival and difficult to measure in the short-term using the conventional endpoint of remission. Response to LSC targeted therapy may be confounded by lack of response of the bulk population. Optimal treatment strategies may ultimately include combined or sequential therapy targeted at both the LSC and bulk leukemia cell populations. However, this approach makes it difficult to measure effects on LSC specifically. In order to isolate specific effects of targeted therapy on LSC, we designed a clinical proof of concept study using serial bone marrow aspirates to measure the effects of LSC-targeted therapy in adults with relapsed acute leukemia. In pre-clinical models, we demonstrated that AKT-β-catenin interaction, indicated by Akt phosphorylation of β-catenin at serine 552 (pS552) is critical for LSC self-renewal. High throughput screening identified daunorubicin (DNR) as a potent inhibitor of pS552. To better understand the role of DNR in specifically targeting LSC, we experimented with lower doses, recognizing that most leukemia patients receive high dose DNR, yet LSC persist and result in disease relapse. In our murine model, low dose anthracycline inhibited LSC number and function. We hypothesized that low dose DNR treatment inhibits LSC number in patients with acute leukemia. Our pilot trial includes relapsed acute myeloid (AML) and lymphoblastic leukemia (ALL) patients (NCT02914977). Bone marrow aspiration was performed at study entry. Patients received DNR at 6.75 mg/m2/day x 5 days followed by repeat bone marrow aspiration on day 8. The plasma pharmacokinetics of low dose DNR was also characterized. Samples from pre- and post-treatment were analyzed by flow cytometry for the frequency (%) of total cells that are pS552-β-catenin positive LSCs (defined as CD34+ CD38- cells that express TIM3, which distinguishes LSCs from normal stem cells). Nine patients (8 AML, 1 ALL) have been treated. Seven patients had previous DNR treatment. Two patients had prior allogeneic stem cell transplant. Five of 9 patients had reduction in LSC number as measured by flow cytometry; 3/5 had prior DNR treatment. In this pilot proof of concept trial, we demonstrate the feasibility of serial bone marrow aspiration to measure biomarkers of LSC response. In our small series, 5/9 relapsed leukemia patients had reduction in LSC number after one cycle of low dose DNR. Future plans include incorporating low dose DNR following conventional chemotherapy in newly diagnosed patients with AML. This clinical proof of concept trial design with serial bone marrow aspirations may also be used to rapidly assess the validity of other LSC markers and targeted agents.

Citation Format: Tara L. Lin, John M. Perry, Xi He, Gregory Reed, Na Zhang, Scott Weir, Joseph P. McGuirk, Linheng Li. Biomarkers of response to leukemia stem cell targeted therapy with low dose daunorubicin in relapsed/refractory acute leukemia [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 CT137.

Abstract 2865: Ciclopirox olamine: A common antifungal agent that inhibits growth of esophageal tumor cells in vitro and in vivo

Esophageal carcinoma continues to carry a poor prognosis due presentation at advanced stages. Current chemotherapeutics often only prolong survival for months to a few years. Drug repositioning is an important pharmacologic strategy that involves investigation and implementation of known drugs for treatment of new diseases. This method significantly reduces the costs required for establishing the safety of a drug and is associated with higher rates of drug approval. Ciclopirox olamine (CPX) is an antifungal agent that has been on the market since the 1970s. The mechanism of action is believed to include disruptions of DNA repair and cell division signals. Recently, however, this drug has been studied for its antitumor properties demonstrated in human rhabdomyosarcoma, breast carcinoma, colon adenocarcinoma, bladder carcinoma, and hematologic malignancies. To date, there are no studies related to the effect of CPX on esophageal cancer. Here, we show that ciclopirox olamine causes growth inhibition of four esophageal cell lines: TE-10, SKGT4, FLO1 and ESO1. This growth inhibition is demonstrated by hexosaminidase assay performed after incubation with the drug for 24-72 h. The IC50 values range between 5-20µM depending on the cell line used. Cell death was also demonstrated by immunofluorescent staining with Hoschst and propidium iodide, which shows a decrease in the number of viable cells with increasing concentrations of CPX. Clonogenicity assay was also performed with each cell line and demonstrates a decrease in the ability of cells to form colonies after 24 and 48 hour treatment with CPX and subsequent incubation in standard media for 5-7 days. Cell cycle analysis demonstrates G0/G1 arrest in cells treated with CPX. The effects of CPX on the cell cycle are further supported by Western blot analysis showing a decrease in in CDK4 and CDK6, which are necessary for cell cycle progression from the G0/G1 phase. We have also found that treatment with CPX results in a decrease in β-catenin in TE10 cells, suggesting that the drug is affecting this pathway to cause growth inhibition of tumor cells. Finally, we used our ESO1 mouse esophageal squamous cell carcinoma cell line for a xenograft study in which tumor cells were injected into the flanks of mice. Mice treated with intraperitoneal injections of 300 mg/m2 of CPX had smaller tumor volumes compared to untreated controls. In summary, we have shown that CPX inhibits growth of esophageal tumor cells both in vitro and in vivo. Our data suggest that CPX induces cell cycle arrest of tumor cells. The mechanism of tumor cell inhibition may be related to downregulation of the WNT/β-catenin signaling pathway. In future studies, we plan to analyze the effects of CPX on other components in the WNT family from in vitro cells as well as tumor xenografts.

Citation Format: Randi J. Ryan, Prabhu Ramamoorthy, Dharmalingam Subramaniam, Shrikant Anant, Scott Weir. Ciclopirox olamine: A common antifungal agent that inhibits growth of esophageal tumor cells in vitro and in vivo [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 2865.

Scientific Opinion on the state of the science on pesticide risk assessment for amphibians and reptiles

Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science to support the potential development of a risk assessment scheme of plant protection products for amphibians and reptiles. The coverage of the risk to amphibians and reptiles by current risk assessments for other vertebrate groups was investigated. Available test methods and exposure models were reviewed with regard to their applicability to amphibians and reptiles. Proposals were made for specific protection goals aiming to protect important ecosystem services and taking into consideration the regulatory framework and existing protection goals for other vertebrates. Uncertainties, knowledge gaps and research needs were highlighted.

Scientific Opinion on the state of the science on pesticide risk assessment for amphibians and reptiles

Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science to support the potential development of a risk assessment scheme of plant protection products for amphibians and reptiles. The coverage of the risk to amphibians and reptiles by current risk assessments for other vertebrate groups was investigated. Available test methods and exposure models were reviewed with regard to their applicability to amphibians and reptiles. Proposals were made for specific protection goals aiming to protect important ecosystem services and taking into consideration the regulatory framework and existing protection goals for other vertebrates. Uncertainties, knowledge gaps and research needs were highlighted.

Abstract B24: Regulation of mutant p53 stability by the mevalonate pathway-Hsp40-CHIP axis

Missense mutations in the p53 gene result in accumulation of dysfunctional p53 proteins in tumors with oncogenic gain-of-function activities, such as metastasis and chemotherapy resistance. Increasing evidence indicates that stabilization of mutant p53 (mutp53) in tumors is crucial for its oncogenic activities, while its knockdown reduces malignant progression. Thus, malignant properties of cancer cells are dependent on the presence of mutp53, providing a rationale to identify compounds that deplete mutp53 with minimal effects on wild-type p53 (wtp53). Toward this goal, we performed luciferase assay-based high-throughput screening of ~9,000 chemical compounds using cells expressing a chimeric fusion protein of p53R175H and a luciferase reporter. This screening led us to identify statins, a class of cholesterol-lowering drugs, as degradation inducers of conformational p53 mutants. Interestingly, statins showed minimal effects on wtp53 and DNA contact mutants. Moreover, CHIP ubiquitin ligase, but not MDM2, mediated statin-induced nuclear export, ubiquitination, and degradation of mutp53. Surprisingly, degradation of mutp53 by statins was independent of protein prenylation/lipidation or cholesterol synthesis, and specific reduction of mevalonte-5-phosphate (MVP) triggered mutp53 degradation. We also demonstrated that downregulation of a molecular chaperone Hsp40/DNAJA1 mirrored statin's effects on mutp53, while its overexpression nullified them. Moreover, statin-induced reduction of MVP inhibited the DNAJA1-mutp53 interaction. Biologically, statins preferentially suppressed malignant properties of mutp53-expressing cancer cells in vitro and in vivo. Our study proposes a novel role of DNAJA1 in inhibiting CHIP-mediated degradation of mutp53 induced by statins and highlights the significance of p53 status in impacting the efficacy of statins in cancer therapy and of DNAJA1 as a viable target for inducing mutp53 degradation.

Citation Format: Alejandro Parrales, Atul Ranjan, Swathi V. Iyer, Scott Weir, Anuradha Roy, Tomoo Iwakuma. Regulation of mutant p53 stability by the mevalonate pathway-Hsp40-CHIP axis. [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 B24.

Targeting p97 to Disrupt Protein Homeostasis in Cancer

Cancer cells are addicted to numerous non-oncogenic traits that enable them to thrive. Proteotoxic stress is one such non-oncogenic trait that is experienced by all tumor cells owing to increased genomic abnormalities and the resulting synthesis and accumulation of non-stoichiometric amounts of cellular proteins. This imbalance in the amounts of proteins ultimately culminates in proteotoxic stress. p97, or valosin-containing protein (VCP), is an ATPase whose function is essential to restore protein homeostasis in the cells. Working in concert with the ubiquitin proteasome system, p97 promotes the retrotranslocation from cellular organelles and/or degradation of misfolded proteins. Consequently, p97 inhibition has emerged as a novel therapeutic target in cancer cells, especially those that have a highly secretory phenotype. This review summarizes our current understanding of the function of p97 in maintaining protein homeostasis and its inhibition with small molecule inhibitors as an emerging strategy to target cancer cells.

Abstract 3690: Metabolic regulation of mutant p53 stability by the mevalonate pathway

Introduction: Mutations in the p53 gene are mostly missense mutations and result in accumulation of dysfunctional p53 protein in tumors with oncogenic gain-of-function activities. Increasing evidence indicates that stabilization of mutant p53 (mutp53) in tumors is crucial for its oncogenic activities including tumor progression and drug resistance, while downregulation of mutp53 reduces oncogenicity of cancer cells. These observations suggest that malignant properties of cancer cells are dependent on the presence of mutp53, thus providing a rationale to identify compounds that deplete mutant p53 with little impact on wild-type p53.

Experimental procedures: Toward this goal, we performed high throughput screens of chemical libraries (∼9,000 compounds) with Saos2 (p53 null) cells expressing a fusion protein of p53R175H and luciferase, using luciferase as a reporter.

Summary of data: This screening led us to identify “statins”, a class of cholesterol-lowering medications, as compounds that induced degradation of p53R175H. We found that other inhibitors of the mevalonate pathway, such as 6-fluoromevalonate and zoledronic acid, failed to induce p53R175H degradation, while statin-mediated inhibition of HMG-CoA reductase and subsequent reduction in mevalonte-5-phosphate triggered p53R175H degradation. These results suggest that statin's effect on p53R175H is specific and independent of protein prenylation/lipidation or cholesterol synthesis. Moreover, nuclear export of p53R175H was required for the statin-mediated degradation, which was mediated through an E3 ubiquitin ligase CHIP, but not MDM2. Interestingly, statins induced degradation of mainly conformational p53 mutants with minimal effects on the levels of wild-type p53 and DNA contact mutants.

Conclusions: This is the first study demonstrating that mutp53 stability is regulated through a specific process of the mevalonate pathway, thereby providing a novel regulatory mechanism of mutp53 degradation. Our findings suggest that p53 mutation status in tumors may have an impact on efficacy of statins in cancer therapy.

Citation Format: Tomoo Iwakuma, Atul Ranjan, Swathi V. Iyer, Subhash Padhye, Scott Weir, Anuradha Roy. Metabolic regulation of mutant p53 stability by the mevalonate pathway. [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 3690.

Abstract 776: Pre-clinical evaluation of ceritinib in anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) is an aggressive CD30+ T-Cell lymphoma that accounts for 2-8% and 10-15% non-Hodgkin lymphomas in adults and children, respectively. The currently used standard therapy for anaplastic lymphoma kinase (ALK, a member of insulin receptor superfamily) positive ALCL has limited effectiveness, resulting in a substantial percentage of cases with poor outcome, either failing to enter remission or relapsing within a few months after starting the treatment. Thus, there is a clear unmet clinical need for developing novel, effective and safer therapeutic strategies for ALCL. Nucleophosmin 1 (NPM1) is a nucleolar phosphoprotein, which functions as a molecular chaperone for proteins and nucleic acids. Approximately 50% of ALCL cases are positive for the NPM-ALK fusion chimera generated by the t(2;5) chromosomal translocation. The oligomerization domain of NPM1 in the fusion protein NPM-ALK, mediates the ligand-independent dimerization of chimeric protein, which results in constitutive activation of the chimeric tyrosine kinase activity leading to downstream signaling pathways responsible for the oncogenicity. Ceritinib is a second generation FDA approved ALK inhibitor for the treatment of ALK-positive metastatic non-small cell lung cancer. Here we report the first preclinical evaluation of ceritinib growth inhibitory effects on ALK-positive ALCL cells. The NPM-ALK expressing ALCL model cell line SUDHL-1 used in our studies. Treatment with ceritinib significantly induced apoptosis dose dependently (10-50nM) in ALCL cells associated with poly (ADP-ribose) polymerase cleavage. Mechanistically, ceritinib blocked phosphorylation of ALK and its downstream signaling effectors STAT3, AKT and ERK1/2. Cell cycle analysis by flow cytometry showed that ceritinib induced G0/G1 arrest with concomitant decrease in the percentage of cells in S and G2/M phases which was associated with decreased cyclin D1 and increased p21 expression. ALCL is also characterized by strong expression of the cytokine receptor CD30 (a member of the TNF receptor family). CD30 stimulation leads to NF-kB activation and the induction of anti-apoptotic mechanisms. In response to ceritinib treatment, flow cytometry data showed that reduced CD30 expression in a dose dependent manner. Altogether, these pre-clinical results demonstrate that ceritinib induces apoptosis in ALCL cells by inhibiting ALK downstream signaling cascade and support the rational for in vivo testing of ceritinib for the treatment of ALK positive lymphomas.

Citation Format: Siddhartha Ganguly, Sudhakiranmayi Kuravi, Satyanarayana Alleboina, Brandon Weckbaugh, Deepti Satelli, Jensen Roy, Scott Weir, Joseph McGuirk, Ramesh Balusu. Pre-clinical evaluation of ceritinib in anaplastic large cell lymphoma. [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 776. doi:10.1158/1538-7445.AM2015-776

Abstract 1895: Ciclopirox prodrug for the prevention and therapy of non-muscle invasive bladder cancer

Objective: Ciclopirox prodrug for the prevention of Non-Muscle Invasive Bladder Cancer (NMIBC) represents a potential breakthrough in the management of high-grade, NMIBC. If successful, this represents the first systemic approach to manage NMIBC. Ciclopirox olamine, the active pharmaceutical ingredient in several topical antifungal drug products, has demonstrated anticancer activity in blood and solid tumors. We developed a phosphoryloxymethyl prodrug of ciclopirox (CPX) for efficient intravenous delivery, thereby avoiding dose-limiting gastrointestinal toxicities and first-pass effect associated with oral administration.

Methods: In vitro anticancer activity of CPX was performed in both NMIBC (T24) and MIBC (253-JBV) cell lines. Cell proliferation was determined by hexoseaminidase assay. Stemness was determined by the Spheroid assay. Flow cytometric analyses was performed for cell cycle analysis. RT-PCR array analysis was performed to identify signaling pathways. Real Time PCR, western blot and immunofluorescent studies were performed for determining gene expression.

Results: Pharmacokinetic studies conducted in mice, rats and dogs demonstrated that the drug is rapidly and completely metabolized and eliminated via the urine. In vitro, CPX inhibited growth of T24 and 253-JBV cells at 4 and 2 μM, respectively coupled with S-phase cell cycle arrest. FITC conjugated Annexin V-coupled flow cytometry studies showed that CPX induces apoptotic cell death. CPX also suppressed bladdosphere formation, suggesting that stem cells are affected. Notch signaling pathway plays a significant role in stem cell behavior, and previous studies have suggested that the pathway may be a therapeutic target for bladder cancer. Notch receptor activation, which occurs following ligand binding, involves specific intracellular cleavage by the γ-secretase complex. First, RT-PCR array analyses suggested that CPX inhibits the Notch signaling pathway. Furthermore, CPX significantly inhibited the expression of the γ-secretase complex proteins Presenilin1, Nicastrin, APH-1 and PEN-2. In addition, there was a reduction in the expression of downstream targets of the pathway including Hes1 and Cyclin-D1. These data suggest that CPX significantly inhibits Notch intracellular signaling pathway proteins. Ectopic expression of the activated/cleaved Notch protein reversed CPX mediated inhibition of cell proliferation.

Conclusion: CPX is a novel chemotherapeutic and preventive agent for bladder cancers, and this occurs by suppressing the stem cells. We are confident that there will be no failure of the compound as a result of unacceptable toxicity because drug safety profile of CPX has been previously characterized in animals and humans. These studies provide insight into understanding the role of CPX as a potent chemotherapeutic and preventive agent.

Citation Format: Parthasarathy Rangarajan, Satish Ramalingam, Dharmalingam Subramaniam, Michael J. Baltezor, Robyn Wood, Shrikant Anant, Scott Weir. Ciclopirox prodrug for the prevention and therapy of non-muscle invasive bladder cancer. [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 1895. doi:10.1158/1538-7445.AM2015-1895

Abstract 3632: Synergistic interaction of auranofin with PARP inhibitors in ATM-proficient mantle cell lymphoma

Auranofin (AF) (Ridaura®) is an oral, FDA-approved, lipophilic, gold-containing compound that was used for treating arthritis. Its primary mechanism of action is the inhibition of thioredoxin reductase (TRR) activity. It consequently induces oxidative/ER stress and also inhibits Heat shock protein (Hsp) 90 chaperone function. Ataxia-telangiectasia mutated and Rad3-related (ATR), Brca1, Chk1 and DNA-PK are Hsp90 client proteins that participate in DNA repair pathways. Based on our observation that AF induces DNA damage, we evaluated whether treatment with AF also impairs Hsp90-dependent DNA damage repair pathways in Mantle Cell Lymphoma (MCL) cells. It has been reported that ATM mutations are found in about 50% cases of MCL. Earlier studies have shown that ATM mutant MCL cells are more sensitive to poly-ADP ribose polymerase (PARP) inhibitors in vitro and in vivo. We hypothesized that by inhibiting Hsp90-dependent DNA repair pathways (such as the ATR pathway), AF would sensitize ATM-proficient MCL cells to PARP inhibition by ABT-888. We demonstrate that treatment of ATM-proficient MCL cell lines, JeKo-1, MO2058 and Z138C with AF induced reactive oxygen species (ROS) levels and resulted in a concomitant decrease in TRR activity. Microarray analysis of AF-treated primary MCL cells revealed that AF significantly altered heat shock response genes, ER and oxidative stress-inducible genes and a subset of genes that were regulated by ATM or Brca1. Treatment with AF also induced Hsp90 hyperacetylation and resulted in the depletion of Hsp90 client proteins including ATR, AKT and Cyclin D1 in MCL cells. Exposure to AF induced significantly more apoptosis in primary MCL cells, as compared to CD19+ normal B cells, CD34+ human cord blood and bone marrow progenitor cells (&lt; 15% apoptosis) (p &lt; 0.01). Co-treatment of MCL cells with AF and the PARP inhibitor ABT-888 resulted in synergistic increase in apoptosis of ATM-proficient MCL cells, with an increase in the induction of γH2AX foci and depletion of p-Chk1 (a downstream target of ATR signaling). This was accompanied with a concomitant increase in the levels of the ER stress-induced transcription factor CHOP (C/EBP homologous protein), cleaved Caspase 3 and PARP. Collectively, our data suggests the synthetic lethal effects observed by the simultaneous inhibition of DNA repair pathway(s) and PARP activity can be extended to ATM-proficient MCL cells. These pre-clinical studies create a strong rationale to determine the in vivo activity of the combination ABT-888 with AF in MCL.

Citation Format: Siddhartha Ganguly, Trisha Home, Sumedha Gunewardena, Scott Weir, Joseph McGuirk, Rekha M. Rao. Synergistic interaction of auranofin with PARP inhibitors in ATM-proficient mantle cell lymphoma. [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 3632. doi:10.1158/1538-7445.AM2015-3632

Pharmacokinetic profile of dalfampridine extended release: clinical relevance in patients with multiple sclerosis

BACKGROUND

In January 2010, dalfampridine extended release tablets (dalfampridine-ER [Ampyra *]; prolonged-, modified- or sustained-release fampridine [Fampyra †] in some countries), 10 mg to be administered twice daily approximately 12 hours apart, were approved by the US Food and Drug Administration. This was the first drug indicated to improve walking in patients with MS.

SCOPE

Publications describing the pharmacokinetics of dalfampridine-ER or the immediate release formulation were identified from a search of PubMed through June 2012 using the search terms 'dalfampridine OR fampridine OR 4-aminopyridine' AND 'pharmacokinetics' and were supplemented with unpublished studies made available by Acorda Therapeutics Inc.

FINDINGS

Pharmacokinetic studies show dose proportionality, with dalfampridine-ER having a more favorable profile than immediate-release dalfampridine. With twice-daily dosing of dalfampridine-ER, time to peak plasma concentration (3.2-3.9 hours) and apparent terminal plasma half-life (5.6-6.4 hours) are approximately twice those of immediate-release formulations, with comparable overall exposure and peak plasma concentrations (21.6 ng/mL) that were maintained at levels approximately 50% lower than immediate release. Steady state is achieved within 39 hours; pharmacokinetics are predictable based on single dosing. Trough plasma concentrations of 13-15 ng/mL are required to maintain efficacy. Renal excretion is predominantly as unchanged compound, and renal clearance in healthy individuals exceeds the glomerular filtration rate. Since dalfampridine-ER exposure increases with renal impairment, it is contraindicated in patients with moderate or severe impairment in the US, and in patients with any renal impairment in the European Union.

CONCLUSIONS

Dalfampridine-ER has low protein binding, is not a substrate for p-glycoprotein and does not affect CYP450 enzymes, suggesting a low potential for drug-drug interactions. Because of the narrow therapeutic range and risk of adverse events, including seizure, with increasing plasma concentrations, the recommended dose and regimen of dalfampridine-ER should not be exceeded and not be used with other dalfampridine formulations. A limitation of this review is that it includes some data that have not yet been published.

Population pharmacokinetics and pharmacodynamics of dalfampridine-ER in healthy volunteers and in patients with multiple sclerosis

OBJECTIVE

Using data pooled from several studies of dalfampridine extended release (ER), a population pharmacokinetic model was developed for the purposes of characterizing the population pharmacokinetics and pharmacodynamics of dalfampridine-ER with respect to variability in pharmacokinetics, covariates affecting the pharmacokinetics, and whether the current therapeutic dosage represents an optimal dosage. Studies were conducted in healthy volunteers and multiple sclerosis (MS) patients over the course of development and registration of dalfampridine extended release tablets (dalfampridine-ER [Ampyra *]; prolonged-, modified- or sustained-release fampridine [Fampyra †] in some countries).

METHODS

The model used to best describe the population pharmacokinetics of dalfampridine-ER was an open, one-compartment model with first-order absorption, first-order elimination and an absorption lag time.

RESULTS

The population median estimated oral clearance was 36 L/h for a 50-year-old woman with a creatinine clearance of 105 mL/min and 42 L/h for a comparable man. The typical volume of distribution was 304 L for women and 403 L for men. The estimated absorption rate constant was 1.22 hours(-1) in the fasted state and 2.22 hours(-1) when given with food. The covariates identified as having a significant effect (p < 0.01) on model fit were food and gender on absorption rate, and gender, age and creatinine clearance on oral clearance. Only creatinine clearance and age are of clinical relevance. Concomitant medications did not affect any of the parameters in the model. Exposure-response relationships for both efficacy and safety were consistent with what has been observed in clinical trials. Limitations of this study include some reliance on unpublished data, and the limited effectiveness of the model for determining the likelihood of the efficacy and safety of dalfampridine-ER in clinical practice.

CONCLUSIONS

The approved therapeutic dosage regimen of dalfampridine-ER 10 mg twice daily was identified as the optimum dosing regimen based on model-predicted exposure response relationships for efficacy and adverse events. A limitation of this study is the limited effectiveness of the models used to predict long-term efficacy and safety of dalfampridine-ER in clinical use.

Abstract B32: Gedunin induces autophagy during mitosis, a novel form of mitotic catastrophe

Background: Breast Cancer is the most prevalent cancer in the world and the second leading cause of cancer death among women in the United States. Triple negative breast cancer (lacking estrogen receptors (ER), progesterone receptors (PR) and human epidermal growth factor receptor 2 (HER2)) can be extremely aggressive and is more likely to recur and metastasize than other subtypes of breast cancer. They are also unresponsive to the most effective receptor targeted treatments. A different treatment strategy is essential to fight against the triple negative breast cancer cells. Heat shock protein 90 (Hsp90) is a molecular chaperone that is required for the stability and function of various signaling proteins that promote the growth and/or survival of cancer cells. Several Hsp90 inhibitors are currently under clinical trial for the treatment of cancer. One natural HSP90 inhibitor is gedunin, which was isolated from the Indian neem tree (Azadirachta indica L.). Here we present our results of studies on the effect of gedunin on BT20 triple negative breast cancer cells and HMLE immortalized breast epithelial cells.

Method: BT20 and HMLE cells were grown according to ATCC guidelines. Flow cytometric analyses for cell death was performed using the Apoptosis/Necrosis detection kit (Roche). MDC incorporation and electron microscopic were performed to detect autophagy. BT20 tumor xenografts were used for determining the effect of gedunin in vivo. Real Time PCR, western blot and immunefluorescent studies were performed for determining gene expression.

Results: Gedunin induced a dose (0-20 μM) and time (0-72 h) dependent cytotoxicity, with significant inhibition of colony formation of BT20 cells at a concentration of 8 μM. However, gedunin did not affect the viability of HMLE cells. Cell cycle analyses demonstrated G2/M phase arrest of the BT20 cells. Electron microscopy studies revealed that gedunin induced the formation of autophagosomes, which was further confirmed by the monodansylcadaverine (MDC) incorporation. Real time-PCR and Western blot analyses revealed that gedunin induced the expression of autophagy related genes ATG5, ATG7, ATG12 and Beclin1. Furthermore, there was increased cleavage and lipidation of microtubule associated protein 1 light chain 3 (LC3B). Mechanistically, we have identified that gedunin induced phosphorylation of AMP kinase, which induces a signaling casade starting with phosphorylation of ULK1. This was suppressed when cells were either treated with an AMPK inhibitor Compound C or AMPK was downregulated with specific siRNA. There was also a reduction in gedunin-induces cell death. These data suggest that gedunin-mediated induction of autophagy occurs in part via the AMPK pathway. We have confirmed these findings in vivo using BT20 nude mice tumor xenografts. Intraperitoneal gedunin administration (5 mg.Kg bw) significantly decreased tumor growth. Western blot analyses showed increased expression of autophagic markers LC3B and Beclin1 in the gedunin-treated tissues which was further confirmed by the immunohistochemistry. More importantly, we observed increased number of autophagasomes in cells undergoing mitosis (p-Histone H3 staining).

Conclusion: Together, these data suggest that gedunin effectively drives triple negative breast cancer cells to an unusual form of mitotic catastrophe by inducing AMPK mediated autophagy during mitosis.

Citation Format: Parthasarathy Rangarajan, Prabhu Ramamoorthy, Satish Ramalingam, Dharmalingam Subramaniam, Sivapriya Ponnurangam, Scott Weir, Shrikant Anant, Roy Jensen. Gedunin induces autophagy during mitosis, a novel form of mitotic catastrophe. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr B32.

Abstract PR05: Effects of Hsp90 inhibitors on triple-negative breast cancer: Notch as a therapeutic target for stem cells

Background: Breast cancer is the second leading cause of death for woman. Within breast cancer subtypes, those classified as Triple Negative Breast Cancer (TNBC) exhibit dismal survival rates due to their propensity to develop distant metastases. Tumors contain heterogeneous cell populations and it has numerically rare cancer stem cells with indefinite proliferative potential that is responsible for tumor invasiveness, heterogeneity, and therapy resistance. Heat shock protein 90 (Hsp90) is a molecular chaperone that aids in the folding and maturation of various proteins involved in breast cancer progression and resistance to therapy. The aim of this study was to elucidate whether the two natural inhibitors of Hsp90, celastrol and triptolide inhibit triple negative breast cancer growth. Both these compounds are terpenoids and were obtained from the Chinese herb “Thunder God of Vine” (Tripterygium wilfordii).

Methods: BT20, BT549, MDA-MB-231 and MDA-MB-157 cells (all TNBC cells) were obtained and grown in DMEM containing 10% FBS as per ATCC recommendations. Cell proliferation was assessed by hexoseaminidase activity, and IC50 values calculated using GraphPad Prism5. For clonogenicity, 500 cells were treated with IC50 concentration of each compound for 24h, and then allowed to grow and form colonies. Mammosphere assay was performed using 5000 cells/ml in ultra low attachment plates. Images were captured after 5 days. For in vivo, BT20 cells were injected into flanks of athymic nude mice and treated with celastrol and triptolide at 3 mg/Kg bw and 0.25 mg/Kg bw, respectively.

Results: Celastrol and triptolide treatment suppressed the proliferation and colony formation ability of all four TNBC cell lines BT20, BT549, MDA-MB-231 and MDA-MB-157. Interestingly, the mammosphere assay (an assay used to evaluate the self-renewal capacity of the cancer stem cells) revealed that celastrol or triptolide significantly reduces the size and number of spheroids. Furthermore, expression of breast cancer stem cell markers ALDH1 and CD133 were significantly reduced in BT20 cells upon the treatment. Recently, Notch signaling has been shown to be critical for self-renewal of cancer stem cells. Activation of the Notch receptor, a membrane spanning receptor involves the interaction with a ligand resulting in a series of proteolytic cleavage events culminating in the release of the Notch intracellular domain (NICD). This NICD translocates to the nucleus, and together with its interacting partner CSL/RBPJ binds to cognate element and activates the expression of downstream target genes such as Hes-1. In cells treated with either celastrol or triptolide, there was a significant reduction in NICD, and its downstream target Hes-1. Furthermore, there was a reduction in ALDH+ cells. However, in cells where we ectopically overexpressed NICD, neither compound was as potent as control vector transfected cells in reducing proliferation, colony formation or mammosphere formation, suggesting the direct role for inhibiting Notch activation as a mechanism of action for the two compounds. We confirmed these finding in vivo using BT20 tumor xenografts grown in athymic nude mice. There was a reduction in the size of tumors in mice treated with celastrol or triptolide. In addition, western blot and immunohistochemistry analyses demonstrated a reduction in the number of ALDH+ and CD133+ cells.

Conclusion: Taken together these data suggest that both celastrol and triptolide affect cancer stem cells in TNBC, in part through inhibition of Notch signaling.

This abstract is also presented as Poster B31.

Citation Format: Prabhu Ramamoorthy, Sydney Byrne, Satish Ramalingam, Parthasarathy Rangarajan, Dharmalingam Subramaniam, Scott Weir, Shrikant Anant, Roy Jensen. Effects of Hsp90 inhibitors on triple-negative breast cancer: Notch as a therapeutic target for stem cells. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr PR05.

Phase I clinical trial of the intraperitoneal (IP) administration of a novel nanoparticle formulation of paclitaxel (NTX)

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Background: IP therapy is an attractive option for patients with IP carcinomatosis as many of these malignancies remain confined IP. Agents whose plasma clearance rates substantially exceed their rates of uptake from the peritoneal cavity are especially suited for IP administration. Pre-clinical studies of a novel formulation of nanoparticulate paclitaxel in animal tumor models demonstrated superior activity and substantially reduced systemic toxicity. This allowed for significant IP doses and concentrations, yet yielded very low systemic concentrations of paclitaxel. We report here the results of a Phase I trial of IP administered NTX. Methods: Patients (ECOG≤2) had relapsed, treatment refractory solid IP tumors and adequate organ function. NTX was administered IP as a bolus injection after 500 ml saline followed by IP administration of up to 2 L of saline. We utilized an accelerated dose escalation scheme until one DLT occurred during cycle 1, followed by a standard dose escalation (3+3 design) based on CTCAE V3 toxicities. The pharmacokinetics of IP administered NTX were characterized in plasma and ascites fluid. Secondary objectives were to define the recommended phase 2 dose of NTX, and characterize preliminary activity and toxicity. Results: 20 patients were treated at dose levels from 50 – 275 mg/M2 q 28 days. Primary malignancy was ovarian cancer (74%). Treatment was well tolerated at all dose levels. Common toxicities potentially related to NTX were: gastrointestinal (68%), constitutional (42%), and pain (42%). Average number of cycles received was 2 (range 1 to 6). Best response was stable disease (4 patients, 21%). Median length of disease stability was 99 days (range 85 to 151 days); median time on study patients with stable disease was 313 days (range 142 to 740 days). All Cmax in plasma were less than 35 ng/mL, with ascites fluid Cmax generally greater than 1000 ng/mL. Conclusions: IP NTX is well tolerated. MTD has not yet been reached. Pharmacokinetic data demonstrate significant, persistent IP exposure to paclitaxel with minimal systemic exposure. Accrual at the 275 mg/M2 dose level continues; updated results will be presented. Further clinical development of NTX is indicated. Clinical trial information: NCT00666991.

Detection and enumeration of E. coli O157:H7 in water samples by culture and molecular methods

The performances of three chromogenic agars were evaluated for the recovery of Escherichia coli O157:H7 from spiked dechlorinated tap, ground and surface water, and treated drinking water samples. The chromogenic agars: ChromAgar O157 (CHROM), Rainbow Agar O157 (RB) and HiCrome EC O157 (HC) were compared to cefixime-tellurite Sorbitol MacConkey (CT-SMAC), commonly used for the isolation of E. coli O157:H7. Confirmation of suspect E. coli O157:H7 colonies were performed by colony real-time PCR (C-RTi-PCR) based on the presence of Shiga-toxin genes (stx1 and stx2). Recovery of inoculated E. coli O157:H7 from dechlorinated tap water indicated that RB and CHROM agars demonstrated improved recovery when compared to HC or CT-SMAC. There was a significant drop in recovery on all agars tested after 120h (day 5). Twenty dechlorinated tap and/or treated drinking water samples were inoculated with a pure culture of E. coli O157:H7 (ATCC 43894), and a mixed culture of E. coli O157:H7 (ATCC 43894), E. coli strain K-12, and Enterococcus faecalis (ATCC 063589). After a 48-hour holding time, the recovery using CHROM (99%) and HC (12%) from samples contaminated with the pure culture were found to be significantly different (p<0.05). Recovery results using CHROM (39%) and CT-SMAC (32%) from samples contaminated with the mixed culture after a 48-hour holding time were not significantly different (p>0.05). Analysis by C-RTi-PCR of forty five environmental water samples (surface, sewage, and final effluents) which were negative for E. coli O157:H7 showed an incidence of false suspect positive colonies of 38% (CHROM), 53% (RB), 58% (HC), and 91% (CT-SMAC). Further analysis of eight of the environmental samples inoculated with E. coli (ATCC 43894) showed 100% recovery when utilizing CHROM, 50% when using RB and 40% when using HC. In addition, the C-RTi-PCR positive confirmation rate was 100% for CHROM and HC and 65% for RB. CHROM demonstrated improved recovery of E. coli O157:H7 over RB, HC, and CT-SMAC in terms of sensitivity and specificity.

Gender-specific reduction of hepatic Mrp2 expression by high-fat diet protects female mice from ANIT toxicity

Emerging evidence suggests that feeding a high-fat diet (HFD) to rodents affects the expression of genes involved in drug transport. However, gender-specific effects of HFD on drug transport are not known. The multidrug resistance-associated protein 2 (Mrp2, Abcc2) is a transporter highly expressed in the hepatocyte canalicular membrane and is important for biliary excretion of glutathione-conjugated chemicals. The current study showed that hepatic Mrp2 expression was reduced by HFD feeding only in female, but not male, C57BL/6J mice. In order to determine whether down-regulation of Mrp2 in female mice altered chemical disposition and toxicity, the biliary excretion and hepatotoxicity of the Mrp2 substrate, α-naphthylisothiocyanate (ANIT), were assessed in male and female mice fed control diet or HFD for 4weeks. ANIT-induced biliary injury is a commonly used model of experimental cholestasis and has been shown to be dependent upon Mrp2-mediated efflux of an ANIT glutathione conjugate that selectively injures biliary epithelial cells. Interestingly, HFD feeding significantly reduced early-phase biliary ANIT excretion in female mice and largely protected against ANIT-induced liver injury. In summary, the current study showed that, at least in mice, HFD feeding can differentially regulate Mrp2 expression and function and depending upon the chemical exposure may enhance or reduce susceptibility to toxicity. Taken together, these data provide a novel interaction between diet and gender in regulating hepatobiliary excretion and susceptibility to injury.