bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5116: Identification of new treatment options for Merkel cell carcinoma using high throughput chemical screening
Authors: Gelb Tara , Urban Daniel , Daily Kenneth , Xiao Ying , Shen Min , Hall Matthew , Brownell Isaac
Published: July 2017

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine skin cancer with limited treatment options. Approximately 80% of MCC tumors have Merkel cell polyomavirus (MCPyV) DNA integrated into the host genome, and viral oncogenes are thought to drive carcinogenesis. In contrast, MCPyV-negative (MCPyV-) tumors have higher rates of proto-oncogene mutations. Transcriptome differences between MCPyV+ and MCPyV- tumors further suggests divergent underlying pathologies. In order to develop efficacious treatments for MCC and elucidate the pathophysiologies underlying MCPyV+ and MCPyV- MCC, we screened the effects of mechanistically annotated drug libraries on MCC cell viability (CellTiter-Glo). We screened ~4,500 compounds including the NCGC Pharmaceutical Collection of approved and investigational drugs and the oncology-focused MIPE (Mechanism Interrogation PlatE) library against six MCC cell lines (3 MCPyV+ and 3 MCPyV-). We ran follow-up screens on the above cell lines as well as non-MCC control cells to identify agents that specifically reduced viability in MCC. DNA topoisomerase inhibitors, proteasome inhibitors, and PI3K inhibitors potently and efficaciously reduced viability in all MCC cell lines tested. Moreover, using hierarchical clustering we found that viral status impacted pharmacological responses. For example, a subset of HDAC inhibitors were more potent in MCPyV+ than MCPyV- MCC cells. In contrast, a dual RasGAP/ERK inhibitor more potently reduced viability in MCPyV- MCC cells relative to MCPyV+ MCC cells. Together these results identify existing drugs that can be repurposed for treating MCC. Moreover, they help elucidate the distinct pathophysiology driving MCPyV+ and MCPyV- MCC.

Citation Format: Tara Gelb, Daniel Urban, Kenneth Daily, Ying Xiao, Min Shen, Matthew Hall, Isaac Brownell. Identification of new treatment options for Merkel cell carcinoma using high throughput chemical screening [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 5116. doi:10.1158/1538-7445.AM2017-5116
Abstract 5118: A novel polyamine sulfonamide with anti-leukemic activity
Authors: Vijay Vindhya , Meacham Amy , Drusbosky Leylah , Wise Elizabeth , Cogle Christopher
Published: July 2017

The greatest challenge in treating Acute Myeloid Leukemia (AML) is refractory disease. Although 60-80% of AML patients achieve complete remission after induction chemotherapy, majority of these patients relapse and die of progressive disease. New treatment options targeting the vulnerabilities of AML biology are highly critical for disease regression, in particular the chemo-resistant leukemia-initiating population, to ensure relapse-free survival in patients. Identifying novel druggable targets that are selective to AML despite their location in the vascular niche is thus highly warranted. We developed an in vitro co-culture model consisting of AML cells and Bone Marrow- derived Endothelial Cells (BMECs), mimicking the protective effect of the vascular niche in the bone marrow microenvironment. Using this unique model, and taking advantage of combinatorial chemistry, we performed high-throughput chemical-phenotypic screening of approximately 30 million novel compounds and identified a novel polyamine sulfonamide 2470-51 that can selectively kill AML cells by overcoming the protective effect of the BMECs. In addition to AML blasts, 2470-51 also exhibited highly selective activity against the leukemic stem and progenitor cell population while sparing normal hematopoietic stem and progenitor cells. In vivo studies using patient-derived xenograft models indicated significant regression in AML engraftment post 2470-51 treatment. Target identification experiments involving unbiased label-free shotgun proteomic analysis in combination with targeted Selected Ion Monitoring (SIM) revealed covalent drug binding targets of 2470-51. By performing differential protein expression analysis using ITRAQ analysis, we identified downstream mechanisms that led to mitotic cell cycle arrest and cell death. Collectively, our findings display the in vitro as well as in vivo efficacy of a novel polyamine sulfonamide in eliminating AML, including the leukemia initiating compartment. We also uncover a novel mechanism in AML that can be taken advantage of for selective toxicity. Furthermore, we establish the role of 2470-51 as a potential therapeutic agent in treating AML.

Citation Format: Vindhya Vijay, Amy Meacham, Leylah Drusbosky, Elizabeth Wise, Christopher Cogle. A novel polyamine sulfonamide with anti-leukemic activity [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 5118. doi:10.1158/1538-7445.AM2017-5118
Abstract 5122: Utilizing zebrafish to study the effect strigolactone on breast cancer cells
Authors: Lin Kira , Grivas Christopher , Boru Elema , Dayani Yaron , Berens Eric , Riegel Anna T. , Glasgow Eric , Yarden Ronit I.
Published: July 2017

Strigolactones (SLs) are a novel class of phytohormones that regulates shoot branching patterns and above-ground plant architecture by inhibiting the outgrowth of axillary lateral buds or meristems. The SL analogues (SLAs) inhibit the growth and survival of a wide array of cancer-derived cell lines including: prostate, colon, lung, melanoma, osteosarcoma and leukemic cell lines, while minimally affecting normal cultured cells. Interestingly, cancer cells with high metastatic potential are more sensitive to the inhibitory effect of SLAs than less aggressive cells. Treatment of cancer cells with SLAs leads to the activation of stress-related signaling including p38MAPKs and JNK1/2, and disrupt the microtubule network. Furthermore, a reduction in acetylated-alpha-tubulin was observed in SLA-treated MDA-MB-231 cells. Microtubules dynamics has been proposed as one of the mechanisms that regulate cell migration by acting on lamellipodia formation. The ECIS invasion assay data suggests that even at low concentration of SLA and as soon as 6 hours, SLAs suppress MDA-MB-231 cells’ ability to invade the HUVEC monolayer. To further examine the effect of SLAs on the invasive and metastatic behaviors of cancer cells in vivo, fluorescently labeled MDA-MB-231 cells were used as xenograft models in zebrafish. Embryos injected with MDA-MB-231 cells showed 66.6% metastasis in vehicle treated control fishes, as compared to 22.85% in SLAs treated fishes. This suggests that SLAs are potent inhibitors of cancer dissemination and metastasis.

Note: This abstract was not presented at the meeting.

Citation Format: Kira Lin, Christopher Grivas, Elema Boru, Yaron Dayani, Eric Berens, Anna T. Riegel, Eric Glasgow, Ronit I. Yarden. Utilizing zebrafish to study the effect strigolactone on breast cancer cells [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 5122. doi:10.1158/1538-7445.AM2017-5122
Abstract 5123: Targeted thieno[2,3-d]pyrimidines with fluorinated phenyl side chains as antitumor agents
Authors: Tong Nian , Gangjee Aleem , Povrik Adrianne Wallace , O’Connor Carrie , Dekhneb Aamod Aamod , Hou Zhanjun , Matherly Larry H.
Published: July 2017

The reduced folate carrier (RFC) is ubiquitously expressed in tissues and tumors and is the major tissue transporter for folate cofactors. Folate receptor (FR) α and β, as well as the proton-coupled folate transporter (PCFT), exhibit narrower patterns of tissue expression and are likely to serve more specialized physiologic roles. FRs are expressed in a subset of cancer cells (e.g., ovarian and non-small cell lung cancer for FRα, acute myelogenous leukemia for FRβ), whereas PCFT is expressed in a wide range of human solid tumors but not leukemias. Earlier generations of glycinamide ribonucleotide formyltransferase (GARFTase) and de novo purine nucleotide biosynthesis (e.g., Lometrexol) have shown promise as antitumor drugs. However, these compounds are excellent substrates for RFC and thus are non-selective for tumors, leading to dose-limiting toxicities. We previously reported a novel class of 6-substituted thieno[2,3-d] pyrimidines with a phenyl side chain and 3- and 4-carbon bridge lengths (AGF17 and AGF23, respectively) which selectively targeted FRs but not RFC or PCFT. To increase antitumor efficacy, we synthesized fluorinated analogs of AGF17 and AGF23, designated as AGF309 and AGF304, respectively. AGF309 and AGF304 potently inhibited proliferation of Chinese hamster ovary (CHO) cell lines engineered to individually express human FRα (IC50s of 1.08 and 2.27 nM, respectively) or FRβ (IC50s 0.48 and 1.14 nM, respectively). AGF304 and AGF309 showed nominal activity toward RFC- and PCFT-expressing CHO cells. Both AGF309 and AGF304 were also potently inhibitory toward FRα-expressing human KB human tumor cells (IC50s of 7.19 and 5.27nM, respectively). By analogy with previous iterations of 6-substituted thieno [2,3-d] pyrimidine compounds, growth inhibitory activity by AGF309 and AGF304 likely involves inhibition of de novo purine biosynthesis at GARFTase and potentially a secondary intracellular target. Collectively, our in vitro findings of the potent and selective antitumor activity and FR selectivity suggest that further preclinical evaluation of AGF309 and AGF304 as potential antitumor agents is warranted.

Citation Format: Nian Tong, Aleem Gangjee, Adrianne Wallace Povrik, Carrie O’Connor, Aamod Aamod Dekhneb, Zhanjun Hou, Larry H. Matherly. Targeted thieno[2,3-d]pyrimidines with fluorinated phenyl side chains as antitumor agents [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 5123. doi:10.1158/1538-7445.AM2017-5123
Abstract 5126: Novel indolizino[8,7-b]indole hybrids with potent activity against small cell lung cancer
Authors: Chang Sue-Ming , Wu Ming-Hsi , Pidugu Hima Bindu , Su Tsann-Long , Lee Te-Chang
Published: July 2017

Small cell lung cancer (SCLC) is an aggressive type of lung cancer and accounts for 10% to 15% of all lung cancer cases. The malignancy has a greater tendency to be widely disseminated by the time of diagnosis as well as to develop early resistance to conventional treatments, a cure is difficult to achieve. The current standard therapy for SCLC treatment, either with monotherapy (platinum based drugs) or combination therapy (e.g., cisplatin with irinotecan or topotecan), was shown to cause serious side effects and inevitably evoke drug resistance in a short time period. We have recently synthesized a series of novel bis(hydroxymethyl)indolizino[8,7-b]indole hybrids by fusing β-carboline and bis(hydroxymethyl)pyrrole moieties for antitumor evaluation. These hybrid molecules displayed diverse mechanisms of action involving topoisomerase II (Topo II) inhibition and induction of DNA cross-linking. Our results also showed that they significantly inhibited the cell growth of various human tumor cell lines. Of the tested tumor cell lines, the SCLC cells (H526 and H211) were the most susceptible to compounds BO-2239 and BO-2329. These hybrids induced cell cycle arrest at the G2/M phase and triggered tumor cell apoptotic death. Intriguingly, the substituent at N11 (H or Me) played a critical role in modulating Topo II inhibition and DNA cross-linking. Compared to the compounds with N11-Me group, derivatives having N11-H group profoundly increased Topo II inhibition activity but reduced DNA cross-linking activity. Among these hybrids, BO-2239 (with N11-H) was as potent as irinotecan, but more effective than cisplatin, in nude mice bearing SCLC H526 xenografts. Accordingly, hybrid BO-2239 may be further developed as a potential agent for the treatment of SCLC.

Citation Format: Sue-Ming Chang, Ming-Hsi Wu, Hima Bindu Pidugu, Tsann-Long Su, Te-Chang Lee. Novel indolizino[8,7-b]indole hybrids with potent activity against small cell lung 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 5126. doi:10.1158/1538-7445.AM2017-5126
Abstract 513: The link between polyploidy and replication stress in melanoma
Authors: Vilgelm Anna E. , Johnson C. Andrew , Malikayil Kiran , Raman Dayanidhi , Flaherty David , Higgins Brian , Richmond Ann
Published: July 2017

Genomic instability is a hallmark of cancer implicated in tumor evolution and resistance to therapy. However, the molecular mechanisms that underlie genomic instability are still poorly understood. One common feature of cancer cells is an elevated genomic content (polyploidy) which is also associated with the acquisition of therapy resistance. Here we demonstrate a link between genomic instability and polyploidization in melanoma cells. We show that polyploidy induced by treatment with small molecule inhibitors of various mitotic kinases, such as AURKA, AURKB and PLK1, leads to DNA damage in cells with elevated (>4n) DNA content. This DNA damage results from replication stress exacerbated by limited activation of p53 in malignant melanocytes. Pharmacological induction of p53 in polyploid cells using an MDM2 antagonist reduced DNA damage by blocking re-replication of the polyploid genome as a result of p53-mediated p21 activation and transactivation of DNA repair genes. Notably we found that p21 blockade using siRNA knockdown or genetic knockout shifted polypoid cell response to p53 activation from cytostatic to cytotoxic. As a result, p21-deficient cells exhibited enhanced sensitivity to mitotic blockade combined with p53 induction. Furthermore, TCGA dataset analysis showed poor progression free survival in melanoma patients with high p21 protein expression. These data argue for administering mitotic inhibitors and MDM2 antagonists, which are currently in clinical development, in conjunction with agents that target p21. In summary, our data here reveal that polyploidization can be a mechanism for induction of DNA damage and genomic instability associated with drug resistance in cancer and suggest a novel strategy for targeting these pathways to improve melanoma therapy.

Citation Format: Anna E. Vilgelm, C. Andrew Johnson, Kiran Malikayil, Dayanidhi Raman, David Flaherty, Brian Higgins, Ann Richmond. The link between polyploidy and replication stress in melanoma [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 513. doi:10.1158/1538-7445.AM2017-513
Abstract 5131: Efficient delivery of siRNA targeted CCDC88A mRNA to pancreatic cancer tumor inhibits the invasiveness and metastasis
Authors: Taniuchi Keisuke , Yawata Toshio , Ueba Tetsuya , Saibara Toshiji
Published: July 2017

Introduction: We identified CCDC88A messenger RNA (mRNA) that accumulates in lamellipodia by binding to an RNA-binding protein IGF2BP3 with a next generation sequencer. The objectives of this study are as follows: (1) To identify CCDC88A specific small interfering RNAs (siRNAs) as RNA interference agents that have an inhibitory effect on the invasion and metastasis of pancreatic cancer cells in a mouse model of the invasion and metastasis of pancreatic cancer; and (2) To develop a nucleic-acid delivery system to efficiently transport the siRNAs to PDAC tissue.

Methods: After intravenous injection of CCDC88A-specific siRNAs supplemented with folic acids that can bind to the folic acid receptor—which are highly expressed on pancreatic cancer cells—and polyethylene glycol-chitosan oligosaccharide nanoparticles to a mouse model of invasion and metastasis in which a human pancreatic cell line was transplanted to induce tumor formation in the mouse pancreas, accumulation of the siRNAs in the pancreatic cancer tissue was determined by using an in vivo imaging system. After CCDC88A-specific siRNA accumulation in the pancreatic cancer tissue was identified, invasion to the retroperitoneum as well as metastasis to the lung or liver from the human primary pancreatic tumor was compared between the mice in which CCDC88A-specific siRNA accumulation was identified and those receiving a scrambled control siRNA.

Results: CCDC88A-specific siRNAs could be delivered to the pancreatic cancer cells of cancer-bearing nude mice by supplementation with folic acids and chitosan oligosaccharide nanoparticles. Supplementation with folic acids and chitosan oligosaccharide nanoparticles caused no hemolysis and had no effect on liver, kidney, or pancreatic function. Invasion to the retroperitoneum and metastasis to the lung or liver from the primary pancreatic cancer were suppressed in cancer-bearing nude mice by administration of those siRNAs, which target CCDC88A mRNA accumulated in lamellipodia of pancreatic cancer cells.

Conclusions: This study suggests the potential to develop a siRNA drug to inhibit the invasion and metastasis of pancreatic cancer.

Citation Format: Keisuke Taniuchi, Toshio Yawata, Tetsuya Ueba, Toshiji Saibara. Efficient delivery of siRNA targeted CCDC88A mRNA to pancreatic cancer tumor inhibits the invasiveness and metastasis [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 5131. doi:10.1158/1538-7445.AM2017-5131
Abstract 5134: Novel trifunctional immunoliposome delivery system to minimize resistance and side effects for anticancer therapy
Authors: Vaidya Tanaya R. , Ait-Oudhia Sihem
Published: July 2017

Background: Breast cancer (BC) is the second leading cause of cancer death in women worldwide. About 25% of BCs have overexpression of the HER2 receptor. Although HER2 targeted therapies have shown considerable improvement in HER2-positive BC patients’ outcome, treatment resistance remains a clinical challenge. Here, we sought to develop and evaluate a novel tri-functional immune-liposome (TFIL) that overcomes HER2 treatment resistance and associated cardiotoxicity by dually targeting HER2 on BC cells and CD3 receptors on cytotoxic T-lymphocytes (CTLs).

Material and methods: Anti-HER2 (Trastuzumab) and anti-CD3 (OKT-3) antibodies, were conjugated to lipid nanoparticles by the micelle-transfer method, and the resulting formulation was purified by dextran gradient ultra-centrifugation. Targeted lipid nanoparticles were formulated with a fluorescent lipophilic dye, DiD, for studying receptor binding and internalization. Studies were conducted with HER2-positive BT474 cells and CD3-positive Jurkat cells using flow cytometry analyses. Doxorubicin (DXR) was encapsulated in the nanoparticles by the remote-loading technique for cell-kill experiments. In vitro cell-kill studies were conducted by co-culturing BT474 as the target cells, and peripheral blood mononuclear cells as the effector cells, at varying ratios.

Results: Purified formulations were successfully characterized for conjugation by determining the protein to lipid ratio. Flow cytometry analyses demonstrated successful cell binding and/or internalization of the TFIL with both the HER2 and CD3-positive cell lines. Moreover, these dual-targeted nanoparticles were able to retarget T cells to kill HER2 positive BC cells, and showed improved efficacy compared to non-targeted and plain HER2-targeted formulations in vitro.

Conclusion: A novel drug delivery system, TFIL, that targets HER2 receptors on tumor cells, CD3 on CTLs, and is able to slowly release DXR was successfully developed and evaluated in vitro on HER2 overexpressing BC cells. Our findings show great promise at overcoming resistance and associated cardiotoxicity to present HER2 targeted BC therapies, and may translate into improved anti-tumor activity clinically compared to other treatment options.

Citation Format: Tanaya R. Vaidya, Sihem Ait-Oudhia. Novel trifunctional immunoliposome delivery system to minimize resistance and side effects for anticancer therapy [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 5134. doi:10.1158/1538-7445.AM2017-5134
Abstract 5138: Development of a gold nanoparticle platform capable of selective homing to tumor tissues for intravenous antitumor therapy
Authors: Han Zhen
Published: July 2017

Intratumoral administration of high mobility group nucleosome-binding protein 1 (HMGN1) and R848/resiquimod together with a checkpoint inhibitor can eradicate large established tumors. However, the intratumoral route of administration is difficult to use on cancers of internal organs. To improve potential clinical use of HMGN1 and R848, it is necessary to deliver HMGN1 and R848 systemically to the tumor tissue. Gold nanoparticles (AuNP) have been extensively studied as a vehicle for various types of drugs, including anticancer compounds. In this study, we established a means of generating PEGylated Au-HMGN1-R848 (Au-PEG-HMGN1-R848) complexes, which, upon intravenous IV administration, preferentially target ectopic hepatoma or colon tumor tissue and avoids uptake of the particles by liver and spleen of tumor-bearing mice. Additionally, Au-PEG-HMGN1-R848 complexes were stable and preserved the capacity of HMGN1 and R848 to stimulate the maturation of dendritic cells. IV administration of Au-PEG-HMGN1-R848 complexes plus a checkpoint inhibitor had effective antitumor activity in curing 80% of C57BL/6 mice bearing large (1 cm in diameter) Hepa1-6 hepatoma and Balb/c mice bearing CT26 colon tumors. Therefore, an Au nanoparticle platform capable of selectively delivering HMGN1 and R848 systemically to tumor tissues can be used to effectively to cure ectopic Hepa1-6 hepatoma and CT26 colon carcinoma.

Note: This abstract was not presented at the meeting.

Citation Format: Zhen Han. Development of a gold nanoparticle platform capable of selective homing to tumor tissues for intravenous antitumor therapy [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 5138. doi:10.1158/1538-7445.AM2017-5138
Abstract 514: Genetic load in cancer cell populations
Authors: Zhang Yuezheng , Shen Xu , Li Yawei , Zhu Tianqi , Tao Yong , Li Tao , Wang Di , Li Xueying , Ma Qin , Lu Xuemei , Wang Hurng-Yi , Wu Chung-I
Published: July 2017

Populations accumulate deleterious mutations that have yet to be removed by natural selection. This mutated portion of the population that does not contribute to its fitness is called the genetic load and is proportional to the deleterious mutation rate. Given the genomic instability of cancer cells, the genetic load could be substantial if the instability indeed leads to loss of cell fitness. We hypothesize that because aneuploidy and copy number variations (CNVs) are the most common forms of genome instability, their fitness consequences may determine the genetic load in cancer cells. To test this hypothesis, we randomly selected single cells from a HeLa cell line and measured the cell growth rate via daily cell counting and an MTT cell proliferation assay. We then measured the genetic changes and resulting growth rate variation. We observed rapid generation of heterogeneity in the growth rate within the population. The growth rate of different progeny cells was stable indicating that it is genetically determined. Next, using whole genome sequencing of recently descended clones of a single HeLa cell, we found that cells with fewer newly acquired CNVs have higher proliferation rates vice versa. This indicated that CNV accumulation decreased cell fitness systematically. We next estimated the rate of CNV mutation by measuring the growth rate of two daughter cells from single proliferation and found that there is approximately 1 deleterious mutation in every 4 cell divisions. We speculated that due to a high, deleterious CNV mutation rate, tumor cells inevitably accumulate deleterious CNVs and a large percentage of tumor cells are genetically defective. Accordingly, we observed that the average growth rate of tumor cell populations decreased in the short term since defective cells accumulated in the population and the variation of cellular growth rates within the population increased. By modeling the process of mutation accumulation and measuring cell growth rate, we estimated that the deleterious mutation rate in HeLa cells is about 0.26-0.31 per cell division, and that HeLa cells reduce roughly 5%-6% of fitness for every cell division. The observations of a high proliferation rate and high genetic load in this representative tumor cell line indicates a “high risk, high reward” evolution strategy for tumor cells and suggests that increasing the level of genomic instability may cause the meltdown of tumor cell population by forcing cells to accelerate the cell cycle.

Citation Format: Yuezheng Zhang, Xu Shen, Yawei Li, Tianqi Zhu, Yong Tao, Tao Li, Di Wang, Xueying Li, Qin Ma, Xuemei Lu, Hurng-Yi Wang, Chung-I Wu. Genetic load in cancer cell populations [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 514. doi:10.1158/1538-7445.AM2017-514
Abstract 5140: Encapsulation of the atypical retinoid ST1926 in nanoparticles prolongs the survival of acute myeloid leukemia xenografted mice at multiple folds lower concentrations than the naked drug
Authors: El-Houjeiri Leeanna , Saad Walid , Hayar Berthe , Aouad Patrick , Tawil Nadim , Abdel-Samad Rana , Pisano Claudio , Bazarbachi Ali , Hajj Hiba El , Darwiche Nadine
Published: July 2017

Acute myeloid leukemia (AML) represents one of the most complex types of leukemia. It is a clinically and genetically heterogeneous disorder of hematopoietic progenitor cells, which have lost their ability to differentiate normally. Retinoids regulate vital biological processes including development, differentiation, proliferation, and cell death of hematopoietic progenitor cells. The natural retinoid all-trans retinoic acid (ATRA) became the paradigm for the treatment of acute promyelocytic leukemia (APL), an AML subtype. However, in non-APL AML patients, ATRA is possibly only effective in patients with Nucleophosmin-1 mutations without FMS-like tyrosine kinase 3 internal tandem duplication (FLT-3 ITD). Therefore, synthetic retinoids, specifically the adamantyl ST1926, emerged as potential alternatives. However, despite its lack of toxicity, ST1926 development in clinic was limited due to its rapid glucuroconjugation resulting in low plasma concentrations. Nanomedicine enables more efficient drug delivery and bioavailability. Here, we investigate the pre-clinical efficacy of ST1926 and polymer stabilized ST1926 nanoparticles in AML in vitro and in vivo models. We show that ST1926, at low sub-µM concentrations, potently inhibited the growth of human non-APL ATRA-resistant AML cell lines and AML patient cells while sparing resting and activated normal leukocytes at ten- to hundred-fold higher concentrations. ST1926 induced early DNA damage and massive apoptosis in all tested AML cell lines. To optimize the drug’s bioavailability burden, polymer stabilized ST1926 nanoparticles were developed using Flash NanoPrecipitation, and were shown to display comparable anti-growth activities to the naked drug in vitro. In murine AML xenograft model, ST1926 and ST1926 nanoparticles significantly prolonged survival. Strikingly, ST1926 encapsulated in nanoparticles extended survival in AML xenografted mice at four-fold lower concentrations than the naked drug. These results highlight the promise of ST1926 in AML therapy and warrant further clinical development of this adamantly retinoid.

Citation Format: Leeanna El-Houjeiri, Walid Saad, Berthe Hayar, Patrick Aouad, Nadim Tawil, Rana Abdel-Samad, Claudio Pisano, Ali Bazarbachi, Hiba El Hajj, Nadine Darwiche. Encapsulation of the atypical retinoid ST1926 in nanoparticles prolongs the survival of acute myeloid leukemia xenografted mice at multiple folds lower concentrations than the naked drug [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 5140. doi:10.1158/1538-7445.AM2017-5140
Abstract 5147: Novel warheads for targeted therapies of cancer: The concept and design of proPBDs
Authors: Vlahov Iontcho , Qi Longwu , Hahn Spencer , Wang Kevin , Santhapuram Hari K. , Felten Albert , Kleindl Paul , Vaughn Jeremy , Leamon Christopher P.
Published: July 2017

Pyrrolo[2,1-c][1,4]benzodiazepine (PBD) antibiotics, are a class of natural products produced by various actinomycetes bacteria. PBDs are sequence selective DNA-crosslinking alkylating compounds and are considerably more potent than systemic chemotherapeutic agents. Some PBDs have the ability to recognize and bond to specific sequences of DNA. After insertion in the minor groove, a covalent aminal bond is formed through nucleophilic attack of the N-2 of a guanine (G) base on the electrophillic C-11 imine of PBD. The end result is obstruction of tumor cell division without any significant distortion of the DNA’s helix, thus potentially avoiding the common phenomenon of drug resistance.

In recent years, synthetic PBD-dimers have emerged as a promising class of payloads for conjugates in the field of targeted cancer therapies. Unfortunately, many PBD conjugates preserve the strongly alkylating imine moiety within their structural framework, which can react in a deleterious manner while in circulation on their way to their intended targets. As an elegant solution to this inherent problem we designed conjugated prodrugs lacking the imine moiety. Once the prodrug (proPBD) conjugate enters a targeted cell, cleavage of the linker system in the construct triggers the generation of a reactive intermediate possessing an aldehyde and aromatic amine. An intramolecular reaction subsequently takes place as the aromatic amine adds to the aldehyde with the loss of water to give the imine, and as a result, the diazepine ring.

In our proPBDs, we envision to mask the aldehyde as a hydrolytically sensitive oxazolidine moiety and to exploit its ring system as a part of an arsenal of self-immolative linker systems for conjugation. To prove the range of applications for this new class of latent DNA-alkylators, we designed and prepared a diverse variety of novel warheads, consisting of proPBD dimers, hybrids of proPBD with other powerful alkylating agents, as well as tethers of proPBDs with sequence-selective DNA minor groove binders. The utility of the so prepared novel warheads in the design of small molecule drug conjugates (SMDC) for targeted cancer therapies will be also discussed in the presented poster.

Citation Format: Iontcho Vlahov, Longwu Qi, Spencer Hahn, Kevin Wang, Hari K. Santhapuram, Albert Felten, Paul Kleindl, Jeremy Vaughn, Christopher P. Leamon. Novel warheads for targeted therapies of cancer: The concept and design of proPBDs [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 5147. doi:10.1158/1538-7445.AM2017-5147
Abstract 5152: Cancer stem cell targeted exosomes for the treatment of metastatic breast cancer
Authors: Kibria Golam , Lee Katelyn E. , Ramos Erika K. , Huang Simo , Harding Clifford V. , Lötvall Jan , Liu Huiping
Published: July 2017

Introduction: Therapy resistance and metastasis remain the two biggest challenges of breast cancer that result in a majority of cancer deaths. Cancer stem cells (CSCs) are a subpopulation of cancer cells that can initiate new tumors, remain refractory to conventional therapies, and spread throughout the body. In order to effectively block metastasis, the present study aims to develop novel therapeutics that specifically target breast CSCs and spare normal cells. While nanomedicine represents one of the promising future directions, it is necessary to overcome the shortcomings of synthetic nanoparticles, including bio-instability and off-target toxicity. Here, we aim to bio-engineer the naturally produced cell-secreted small vesicles, exosomes (~100 nm diameter), for a novel therapeutic delivery system.

Methods: Exosomes from the human mesenchymal stem cells (MSCs) were isolated by differential ultracentrifugation, and characterized by multiple approaches including transmission EM, Immunoblotting and immunofluorescence assays to confirm the size, shape and presence of exosomal markers CD63, CD81 and LAMP2B. Exosomes were engineered to express a peptide ligand on its surface to specifically recognize and target CSCs, and the presence of the ligand was confirmed by western blot, flow cytometry (FCM) and a super resolution confocal laser scanning microscopy (CLSM, Leica SP8). The CSC targeting efficiency of the exosomes was evaluated in vitro by FCM and CLSM. Further, the exosomes were loaded with microRNAs (miR-200, miR-30c), as one of the key factors that regulate breast CSC functions, by following a novel transfection technology.

Results: The bio-engineered exosomes specifically target and internalize into the CSCs compared to normal cells with absent expression of the ligand-binding protein. The developed exosomes can effectively deliver candidate miRNAs into the recipient cells and knock down the genes important for functional CSCs. The in vivo targeting of CSCs and therapeutic applications of the exosomes using patient-derived human-in-mouse breast tumor xenograft models are underway.

Conclusion: It is expected that exosome-based miRNA therapeutics will have high biocompatibility, low toxicity, high specificity, and promising efficiency in preclinical and clinical applications to reduce breast cancer metastasis and improve patient survival.

Citation Format: Golam Kibria, Katelyn E. Lee, Erika K. Ramos, Simo Huang, Clifford V. Harding, Jan Lötvall, Huiping Liu. Cancer stem cell targeted exosomes for the treatment of metastatic breast 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 5152. doi:10.1158/1538-7445.AM2017-5152
Abstract 5154: Enhancing tumor blood perfusion using orally active heparin to increase the distribution of anticancer therapeutics inside the tumor tissue
Authors: Choi Jeong Uk , Al-Hilal Taslim A. , Chung Seung Woo , Yun Jisuk , Nam Hwajung , Lee Myungyun , Hwang Jinha , Kim Kyungjin , Byun Youngro , Cho Youngseok , Lee Seong Wook
Published: July 2017

Here, we suggest in the first time that the cancer associated thrombosis(CAT) might be one of the major factor which limit the tumor blood perfusion and drug distribution inside the tumor tissue by reducing the effective radius of blood vessels. In order to prevent CAT and achieve enhanced drug distribution, we developed orally active heparin to be combined with other anti-cancer therapies. We injected dye conjugated fibrinogen and chitosan nanoparticles to mice which were bearing highly thrombotic tumor to visualize CAT and nanoparticle distribution inside the tumor tissue. When CAT is prevented by heparin, we found that nanoparticle distribution and accumulation were significantly enhanced compared to the group not treated with heparin. This results signify that the CAT can limit the tumor perfusion and prevention of CAT can enhance the drug accumulation and distribution. We used highly thrombotic cancer models such as melanoma and pancreatic cancer to evaluate the therapeutic efficacy of the doxorubicin containing nanoparticle and the combination of oxaliplatin and gemcitabine when they are combined with heparin. We have found that when heparin is combined with each therapy, their tumor inhibition efficacy increased about 25% and also confirmed that this synergistic effect comes from enhanced drug distribution inside the tumor tissue by preventing the CAT using anticoagulant. These results were also supported by histological analysis.

We have validated our hypothesis by showing that CAT can limit the tumor perfusion, which in turn brings reduced drug distribution inside the tumor tissue. We also confirmed that our oral heparin could enhance the tumor perfusion and the efficacy of anti-cancer therapeutics by preventing the CAT in the tumor tissue.

Citation Format: Jeong Uk Choi, Taslim A. Al-Hilal, Seung Woo Chung, Jisuk Yun, Hwajung Nam, Myungyun Lee, Jinha Hwang, Kyungjin Kim, Youngro Byun, Youngseok Cho, Seong Wook Lee. Enhancing tumor blood perfusion using orally active heparin to increase the distribution of anticancer therapeutics inside the tumor tissue [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 5154. doi:10.1158/1538-7445.AM2017-5154
Abstract 516: High-throughput functional evaluation of variants of unknown significance in EGFR
Authors: Kohsaka Shinji , Nagano Masaaki , Ueno Toshihide , Suehara Yoshiyuki , Hayashi Takuo , Shimada Naoko , Takahashi Kazuhisa , Suzuki Kenji , Takamochi Kazuya , Takahashi Fumiyuki , Mano Hiroyuki
Published: July 2017

Since transforming mutations in epidermal growth factor receptor gene (EGFR) were first identified in non-small-cell lung carcinoma (NSCLC), advancement of diagnostics for such mutations, and evolution of targeted therapeutics against EGFR has driven unprecedented improvements in the management as well as outcome of patients with this lethal disease. However, next-generation sequencer (NGS)-driven extensive analyses on NSCLC have revealed a large number of variants of uncertain significance (VUS) in EGFR and other regions in the cancer genome that await further investigation. Here we present a mixed all nominated mutants in one (MANO) method to evaluate the transforming potential and drug sensitivity of VUS of oncogenes, and applied this method to 101 non-synonymous EGFR mutants in a high-throughput manner. The sensitivity of individual mutants to tyrosine kinase inhibitors (TKIs) against EGFR was shown diverged, ranging from relatively insensitive mutations such as missense mutations within exon 19 to a highly resistant mutation within exon 21. Our data thus support the importance of examining uncommon mutations within EGFR, and also of functional evaluation of such mutations. Our MANO method may become a novel foundation for in vitro and in vivo assessments of variants of cancer-related genes to deliver precision medicine to individual cancer patients.

Citation Format: Shinji Kohsaka, Masaaki Nagano, Toshihide Ueno, Yoshiyuki Suehara, Takuo Hayashi, Naoko Shimada, Kazuhisa Takahashi, Kenji Suzuki, Kazuya Takamochi, Fumiyuki Takahashi, Hiroyuki Mano. High-throughput functional evaluation of variants of unknown significance in EGFR [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 516. doi:10.1158/1538-7445.AM2017-516
Abstract 5160: Development of REDX05358, a novel highly selective and potent pan RAF inhibitor and a potential therapeutic for BRAF and RAS mutant tumors
Authors: Mason Helen , Scrace Simon , Testar Richard , Rainard Julie , Talab Fatima , Poonawala Ryaka , Smith Philippa , Brooke Harriet , Frith Sarah , Ahmet Jonathan , Hall Jonathan , Sorrell David , Moore Jon , Phillips Caroline , France Dennis , Bingham Matilda , Armer Richard
Published: July 2017

REDX05358 has been identified as a novel, highly selective and potent next generation pan RAF inhibitor with improved therapeutic potential and predicted safety profile. Aberrant signalling via the MAPK pathway is commonly seen in cancer. RAF inhibitors such as Dabrafenib and Vemurafenib have been approved for the treatment of unresectable and metastatic BRAF mutant melanoma, but these agents lack efficacy in BRAF mutant colorectal cancer (CRC), partly because of EGFR-mediated feedback reactivation of the MAPK pathway via CRAF. Furthermore, RAF inhibitor treatment of RAS-mutant, BRAF wildtype melanomas has been associated with other skin cancers, such as cutaneous squamous cell carcinoma due to MAPK pathway paradoxical activation mediated by CRAF. There is therefore a clinical need for novel agents targeting the MAPK pathway that do not have these undesirable properties. Here we present, REDX05358 that demonstrates subnanomolar binding affinity for BRAF and CRAF with high selectivity profile against a panel of 468 kinases that exhibits negligible paradoxical activation due to inhibition of both RAF monomers and dimers. As a result, REDX05358 not only inhibits MAPK signalling in BRAF V600E mutant tumor cells, but also in those harbouring NRAS and KRAS mutations. Furthermore, REDX05358 does not induce feedback reactivation of the pathway through its ability to sustain inhibition of MAPK signalling in CRC cell lines. Correspondingly, profiling of REDX05358 in a panel of CRC, melanoma and NSCLC cell lines shows it has potent anti-proliferative activity in cell lines harbouring BRAF or RAS mutations. REDX05358 is an orally bioavailable, well tolerated small molecule that has demonstrated in vivo efficacy in BRAF V600E CRC xenograft model. In contrast, first generation inhibitors such as Vemarafenib and Dabrafanib have been reported to be ineffective in this genetic background in CRC cell lines and patients. Thus, we have developed a pan RAF inhibitor with unique pharmacological properties enabling it to have utility in treating BRAF and RAS mutant cancers

Citation Format: Helen Mason, Simon Scrace, Richard Testar, Julie Rainard, Fatima Talab, Ryaka Poonawala, Philippa Smith, Harriet Brooke, Sarah Frith, Jonathan Ahmet, Jonathan Hall, David Sorrell, Jon Moore, Caroline Phillips, Dennis France, Matilda Bingham, Richard Armer. Development of REDX05358, a novel highly selective and potent pan RAF inhibitor and a potential therapeutic for BRAF and RAS mutant tumors [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 5160. doi:10.1158/1538-7445.AM2017-5160
Abstract 5163: Characterization of NMS-E194, a selective and potent PERK inhibitor with efficacy in the KMS-11 multiple myeloma
Authors: Perrera Claudia , Pulici Maurizio , Carenzi Davide , Motto Ilaria , Fasolini Marina , Casale Elena , Depaolini Stefania Re , Rizzi Simona , Asa Daniela , Roletto Fulvia , Bindi Simona , Casero Daniele , Banfi Patrizia , Ardini Elena , Amboldi Nadia , Ballinari Dario , Gasparri Fabio , Cribioli Sabrina , Mancini Laura , Ciomei Marina , Donati Daniele , Felder Eduard , Galvani Arturo , Isacchi Antonella , Valsasina Barbara
Published: July 2017

PERK (PKR-like endoplasmic reticulum kinase) is a serine-threonine kinase associated to endoplasmic reticulum membrane. Together with ATF6 and IRE1, PERK is a key effector of the Unfolded Protein Response (UPR), a network of signaling pathways that ensures protein homeostasis in the endoplasmic reticulum. Multiple Myeloma (MM) and other protein-secreting tumors are highly dependent on UPR for survival, and inhibition of PERK may be an effective strategy to inhibit growth of these tumors. Here we describe the in vitro and in vivo properties of NMS-E194, a novel potent and selective ATP-competitive PERK inhibitor belonging to the arylsulfonamide chemical class. NMS-E194 inhibits PERK kinase with a Ki of ca 1.5 nM in biochemical assay and possesses high selectivity towards a panel of 54 kinases. When tested in cell proliferation assays, NMS-E194 is preferentially active on multiple myeloma (MM) and diffuse large B cell lymphoma cell lines. In mechanism of action studies, NMS-E194 shows a bi-phasic behaviour: at low nanomolar doses it activates PERK, causing ATF4 accumulation, while at >200 nM it inhibits PERK and downstream pathway, inducing apoptosis. NMS-E194 possesses a favourable in vitro ADME profile and has promising PK properties in the mouse. NMS-E194 demonstrated strong anti-tumor activity following oral administration at 25 mg/kg daily to mice harbouring luciferized KMS-11 cells in a disseminated growth model of MM, with no overt toxicity. Overall, the data available so far warrant further development of NMS-E194 and support PERK inhibition as a novel therapeutic approach in MM and other PERK-dependent tumors.

Citation Format: Claudia Perrera, Maurizio Pulici, Davide Carenzi, Ilaria Motto, Marina Fasolini, Elena Casale, Stefania Re Depaolini, Simona Rizzi, Daniela Asa, Fulvia Roletto, Simona Bindi, Daniele Casero, Patrizia Banfi, Elena Ardini, Nadia Amboldi, Dario Ballinari, Fabio Gasparri, Sabrina Cribioli, Laura Mancini, Marina Ciomei, Daniele Donati, Eduard Felder, Arturo Galvani, Antonella Isacchi, Barbara Valsasina. Characterization of NMS-E194, a selective and potent PERK inhibitor with efficacy in the KMS-11 multiple myeloma [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 5163. doi:10.1158/1538-7445.AM2017-5163
Abstract 5170: HDAC inhibitors and the mechanism of resistance in colorectal cancer: RAS and MYC - the partners in crime
Authors: Ispasanie Sylvia S. , Boehme Lena , Eilers Martin , Brummer Tilman , Klotz-Noack Kathleen , Kuhn Natalia , Gastl Bastian , Sers Christine
Published: July 2017

Although histone deacetylase inhibitors (HDACi) are considered a promising novel therapeutic approach in the light of their potent tumour-selective effects, the use of these inhibitors for treatment of colorectal cancer (CRC) have thus far demonstrated limited success as a monotherapy. What this eventually boils down to is our incomplete understanding of the molecular mechanisms, the impact of oncogenes, and thus the key pathways through which HDACi affect tumour cell growth. To shed further light on this, the involvement of oncogenic RAS - a key driver of CRC, in determining the responsiveness to HDACi has been explored. By using cell line model systems harbouring conditional oncogenic NRAS, KRAS and HRAS, we uncovered an oncogenic RAS-dependent “safeguard” mechanism imposed in order to evade the cytotoxic effect of HDACi and therefore apoptosis. Characteristically, cells harbouring oncogenic RAS were observed to undergo a reversible senescence-like growth arrest in G2, allowing for re-entry into cell cycle following the withdrawal of HDACi. This mechanism is implemented as a consequence of the direct targeting of RAS by HDAC inhibition, which resulted in a further amplified GTP-binding activity and subsequent signalling through the MAPK pathway. The observed outcome was an increase in the priming of MYC for ubiquitin-mediated proteasomal degradation, thereby enabling the cells to exit the cell cycle and enter the protective state of G2 arrest. This process was functionally reversed with a conditional non-degradable MYC (T58A/S62A), which in turn rendered the cells more susceptible to undergo apoptosis. Conclusively, in the context of a constitutively activating RAS mutation, the prospect of HDACi treatment was effectively improved using current MAPK-targeted therapy by preventing the observed pro-oncogenic effect of the HDACi treatment alone.

Note: This abstract was not presented at the meeting.

Citation Format: Sylvia S. Ispasanie, Lena Boehme, Martin Eilers, Tilman Brummer, Kathleen Klotz-Noack, Natalia Kuhn, Bastian Gastl, Christine Sers. HDAC inhibitors and the mechanism of resistance in colorectal cancer: RAS and MYC - the partners in crime [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 5170. doi:10.1158/1538-7445.AM2017-5170