bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A136: KDM5A activity inhibition by 2-PCPA: overcoming tolerance to bortezomib
Authors: Terui Yasuhito , Mishima Yuji , Hatake Kiyohiko
Published: August 2018

Purpose: The proteasome inhibitor bortezomib has shown impressive clinical activity alone and in combination with conventional and other novel agents for myeloma treatment. Although bortezomib is known to be a selective proteasome inhibitor, the downstream mechanisms of cytotoxicity and drug resistance remain to be understood. However, resistance to bortezomib as a single agent develops in the majority of patients, and activity in other malignancies has been less impressive. To overcome bortezomib resistance, we compared differential gene expression profiles of bortezomib-resistant and bortezomib-sensitive IM-9 cell lines in response to bortezomib, and expressions of KDM5A genes were significantly increased. Methods: The differential gene expression profiles of bortezomib-resistant IM-9 and bortezomib-sensitive IM-9 cell lines in response to bortezomib were performed using Affymetrix GeneChip. To confirm the results, real-time PCR and Western blot analysis were performed. Bortezomib-resistant IM-9 cells were treated with or without bortezomib and</>or histone demethylase inhibitor, trans-2-phenylcyclopropylamine hydrochloride (2-PCPA). Moreover, level of histone methylation was examined by Western blot analysis. Results: At concentrations that effectively inhibited proteasome activity (maximum dose with 100nM), bortezomib induced cell death in bortezomib-sensitive IM-9 cells, but not in bortezomib-resistant IM-9. In comparison of differential gene expression profiles between bortezomib-resistant IM-9 and bortezomib-sensitive IM-9 cells, we showed overexpression of KDM5A, which is associated with chromatin-mediated reversible drug-tolerant state, Moreover, 2-PCPA overcomes bortezomib resistance in a dose-dependent manner. The histone demethylation at H3K4, H3K9, and H3K27 was suppressed with 2-PCPA. Conclusion: Histone lysine-specific demethylase inhibitor, 2-PCPA, with bortezomib may be useful for overcoming bortezomib resistance in myeloma cells by suppression of KDM3A and KDM5A activities.

Citation Format: Yasuhito Terui, Yuji Mishima, Kiyohiko Hatake. KDM5A activity inhibition by 2-PCPA: overcoming tolerance to bortezomib [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A136.
Abstract A145: SHP2 inhibition restores sensitivity to ALK inhibitors in resistant ALK-rearranged NSCLC
Authors: Dardaei Leila , Wang Hui Qin , Singh Manrose , Fordjour Paul , Yoda Satoshi , Kerr Grainne , Liang Jinsheng , Cao Yichen , Chen Yan , Gainor Justin , Friboulet Luc , Dagogo-Jack Ibiayi , Myers David , Labrot Emma , Ruddy David , Parks Melissa , Lee Dana , DiCecca Richard , Moody Susan , Hao Huaixiang , Mohseni Morvarid , LaMarche Matthew , Williams Juliet , Hoffmaster Keith , Caponigro Giordano , Shaw Alice , Hata Aaron , Benes Cyril , Li Fang , Engelman Jeffrey
Published: August 2018

Most anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung tumors initially respond to small-molecule ALK inhibitors, but drug resistance often develops. After tumors develop resistance to highly potent 2nd-generation ALK inhibitors, approximately half harbor ALK resistance mutations, while the other half have other mechanisms of resistance. The latter often have activation of at least one of several different tyrosine kinases driving resistance. Such tumors are not expected to respond to the 3rd-generation ALK inhibitor, lorlatinib, which is able to overcome all clinically identified ALK resistance mutations, and further therapeutic options are limited. Herein, we deployed an shRNA screen of 1000 genes in multiple ALK inhibitor-resistant patient-derived cells (PDC) to discover sensitizers to ALK inhibition. This approach identified SHP2, a non-receptor protein tyrosine phosphatase, as a common targetable resistance node in multiple PDCs. SHP2 provides a parallel survival input downstream of multiple tyrosine kinases that promote resistance to ALK inhibitors. The recently discovered small-molecule SHP2 inhibitor, SHP099, in combination with the ALK TKI (tyrosine kinase inhibitor), ceritinib, halted the growth of resistant PDCs by preventing compensatory RAS and ERK1/2 reactivation. These findings suggest that combined ALK and SHP2 inhibition may be a promising therapeutic strategy for resistant cancers driven by several different ALK-independent resistance mechanisms.

Citation Format: Leila Dardaei, Hui Qin Wang, Manrose Singh, Paul Fordjour, Satoshi Yoda, Grainne Kerr, Jinsheng Liang, Yichen Cao, Yan Chen, Justin Gainor, Luc Friboulet, Ibiayi Dagogo-Jack, David Myers, Emma Labrot, David Ruddy, Melissa Parks, Dana Lee, Richard DiCecca, Susan Moody, Huaixiang Hao, Morvarid Mohseni, Matthew LaMarche, Juliet Williams, Keith Hoffmaster, Giordano Caponigro, Alice Shaw, Aaron Hata, Cyril Benes, Fang Li, Jeffrey Engelman. SHP2 inhibition restores sensitivity to ALK inhibitors in resistant ALK-rearranged NSCLC [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A145.
Abstract A156: Traditional chemotherapeutic agents as selective inhibitors of glutaminase isozymes
Authors: Katt William P. , Cerione Richard A.
Published: August 2018

Most cancer cells undergo a number of metabolic changes, which dramatically alter their nutritional and energetic pathways. One such alteration is an addiction to glutamine, an abundant nutrient in blood that is much less utilized by healthy tissues. The glutaminase enzymes help cancer cells satisfy their metabolic requirements by acting as the first step in glutamine’s supply of carbon into the citric acid cycle. Two major isozymes of glutaminase exist, a kidney isozyme and a liver isozyme, and these are differentially expressed across different cancers. While the importance of these enzymes has been increasingly appreciated in the literature, and the inhibition of either enzyme has been shown to be detrimental to the growth of numerous cancers both in cell culture and in vivo, medicinal chemistry efforts to target either enzyme have largely involved just one class of compound, based around the scaffold of BPTES, which potently inhibits only the kidney glutaminase isozyme. It is generally accepted that most drugs have at least one off-target or biologic activity that was not intended. In order to determine new inhibitors of either isozyme of glutaminase, we examined the approved oncology drug set from the NIH, which included 119 FDA-approved, clinically relevant compounds. By assaying inhibition of the function of recombinantly expressed purified enzymes, and examining the production of ammonia (a byproduct of glutaminase catalytic activity) in drug-treated cancer cells, we found that several of the drugs in the library, such as cisplatin, not only inhibit glutaminase at biologically meaningful concentrations, but inhibit one isozyme much more potently than the other. This study both shows the power of screening traditional chemotherapeutic agents against more recently identified therapeutic targets and reveals several new scaffolds that might be optimized to potently inhibit these critical enzymes.

Citation Format: William P. Katt, Richard A. Cerione. Traditional chemotherapeutic agents as selective inhibitors of glutaminase isozymes [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A156.
Abstract A165: Novel thiosemicarbazone, Dp44mT, promotes NDRG1 to downregulate oncogenic signaling pathways in cancer
Authors: Menezes Sharleen V. , Kovacevic Zaklina , Richardson Des
Published: August 2018

Introduction: The novel thiosemicarbazone, Dp44mT, has shown potent anticancer activity against various cancer types. The activity of this agent is, at least in part, mediated by its ability to upregulate the growth and metastasis suppressor, N-myc Downstream Regulated Gene 1 (NDRG1). NDRG1 inhibits cell proliferation, migration, and invasion by negatively regulating numerous oncogenic signaling pathways. However, the mechanisms by which NDRG1 modulates all these pathways remain to be elucidated. To examine how NDRG1 and Dp44mT affect multiple signalling pathways, we assessed their effects on the ErbB-family of receptor tyrosine kinases, namely epidermal growth factor receptor (EGFR), human epidermal growth factor 2 (HER2) and human epidermal growth factor receptor 3 (HER3), as these molecules are key regulators of downstream oncogenic signaling. Methods: PANC1 pancreatic and HT-29 colon human cancer cells were utilized to examine the effects of NDRG1 and Dp44mT on EGFR, HER2, and HER3 levels, localization, and phosphorylation in vitro. PANC1 xenografts were also utilized to examine the effects of Dp44mT on these molecules in vivo. Results: For the first time, we demonstrate that NDRG1 and Dp44mT markedly inhibit the expression, localization, and activation of EGFR, HER2, and HER3. NDRG1 also reduced activation of the MAPK-signalling pathway, which is downstream of the ErbB family of receptors. Further, the anticancer agent, Dp44mT, significantly reduced expression of EGFR, HER2, and HER3 in vivo. Conclusions: This study demonstrates for the first time that the novel thiosemicarbazone, Dp44mT, inhibits the ErbB family of proteins through its upregulation of NDRG1, providing an interesting insight into the mechanisms behind its compelling anticancer activity.

Citation Format: Sharleen V. Menezes, Zaklina Kovacevic, Des Richardson. Novel thiosemicarbazone, Dp44mT, promotes NDRG1 to downregulate oncogenic signaling pathways in cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A165.
Abstract A198: The leptin transduction pathway may be targeted against invasive ductal carcinoma of breast
Authors: Rahman Shaikh M. , Al-Shibli Saad M. , Amjad Nasser M. , Al-Kubaisi Muna K. , Harun Norra B. , Nafie Emad M.
Published: August 2018

Despite some controversies, it is generally suggested that obesity imparts a higher risk of breast cancer, the most common cancer among women all over the world. Since obese people usually have higher serum levels of leptin, a hormone secreted by white adipose tissue, the hormone is suspected as the link between adiposity and breast cancer. In this study we tried to explore a possible causal association of obesity and serum leptin with breast cancer by studying a sample of healthy controls and patients from Malaysian population. The control group comprised 40 women with negative mammogram for breast cancer, while the patient group comprised 51 women with invasive ductal carcinoma (IDC) of breast, who were going to be operated. We measured the common obesity parameters, confirmed the diagnosis of IDC of breast in the patients by standard histopathologic examination using hematoxylin and eosin stain, and estimated serum leptin levels using ELISA procedure. We estimated both pre- and postoperative samples of leptin from the patient group. Our results showed a highly significant difference in the serum leptin level between the control group and the patient group with a mean of 20.59 ± 14.4 ng/ml and 38.71 ± 12.2 ng/ml, respectively, having a P value of < 0.001. Our study showed no difference between the pre- and postoperative serum leptin levels in the patient group (P = 0.414). We found no significant difference between body mass index (BMI) of the control and the patient groups (P=0.699), and while in the control group there was strongly positive correlation between serum leptin level and BMI (rs = 0.598, P < 0.01), the patient group showed a positive but much weaker correlation (rs = 0.217, P > 0.05). Our results suggest that compared to BMI, serum leptin has a much stronger association with IDC; since the source of high leptin in serum is not breast cancerous tissue, leptin cannot be a marker for IDC of breast; however, the hormone most likely is causally associated with the tumorigenesis of breast cancer. The results also indicate that obesity, as indicated by BMI, is weakly associated with IDC; however, broader studies with much larger sample sizes are needed to draw any definitive conclusion. We hypothesize that reducing leptin levels, blocking its downstream tissue specific signal transduction, and/or blocking the upstream leptin receptor pathway might help in the prevention and therapy of breast cancer.

Citation Format: Shaikh M. Rahman, Saad M. Al-Shibli, Nasser M. Amjad, Muna K. Al-Kubaisi, Norra B. Harun, Emad M. Nafie. The leptin transduction pathway may be targeted against invasive ductal carcinoma of breast [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A198.
Abstract A201: Discovery of TSR-033, a novel, potent anti-human LAG-3 therapeutic antibody
Authors: Ghosh Srimoyee , Laken Haley , Travers Jon , Kamar Sujatha , Jun H. Toni , Kehry Marilyn R. , Jenkins David
Published: August 2018

Lymphocyte activation gene-3 (LAG-3) is an inhibitory receptor expressed on immune cells. Similar to other immune inhibitory receptors such as programmed death-1 (PD-1), LAG-3 ligation suppresses T-cell activation and cytokine production following antigen stimulation. Despite favorable response rates observed with PD-1 or PD-1 ligand blockade in the treatment of human cancers, there remain many patients who either derive little clinical benefit from such therapies (primary resistance) or suffer a relapse (acquired or adaptive immune resistance). LAG-3 has been implicated in tumor extrinsic resistance mechanisms, due in part to its upregulation following PD-1 blockade, suggesting that targeting this pathway in addition to PD-1 may engender stronger and more durable antitumor immune responses. TSR-033 is a potent and selective humanized monoclonal antibody of the IgG4/kappa isotype, generated through the use of a proprietary in vitro somatic hypermutation antibody discovery technology platform. TSR-033 binds to human LAG-3 and blocks the interaction between LAG-3 and its ligand, major histocompatibility complex class II, expressed on Daudi cells. When evaluated for C1q and CD16a binding, TSR-033 displays properties typical of a human IgG4 antibody, suggesting that it is unlikely to mediate appreciable complement-dependent cytotoxicity or antibody-dependent cell cytotoxicity. Functionally, TSR-033 enhanced T-cell activation in vitro in both SEB-driven and mixed lymphocyte reaction assays. The combination of TSR-033 with a ligand blocking anti-PD-1 antibody further augmented T-cell activation in both systems, as evidenced by increased cytokine production, relative to each individual reagent. Analogous studies using surrogate anti-mouse antibodies also demonstrated that combined blockade of PD-1 and LAG-3 significantly boosted IFNγ production in an in vitro model of murine CD4 T cell exhaustion. Furthermore, anti-LAG-3 combined with anti-PD-1 improved therapeutic efficacy in mouse syngeneic tumor models, eliciting durable immunologic memory upon tumor rechallenge and altering intratumoral and splenic T-cell populations, consistent with heightened immune activation. Taken together, the pharmacologic activity of TSR-033 demonstrates that it is a potent anti-LAG-3 therapeutic antibody and supports its clinical investigation in cancer patients.

Citation Format: Srimoyee Ghosh, Haley Laken, Jon Travers, Sujatha Kamar, H. Toni Jun, Marilyn R. Kehry, David Jenkins. Discovery of TSR-033, a novel, potent anti-human LAG-3 therapeutic antibody [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A201.
Abstract B002: CD47 expression predicts efficacy of macrophage-mediated phagocytosis of tumor cells
Authors: Yang Huajun , Li Zhongliang , Tang Beibei , Xing Frank , Shi Qian
Published: August 2018

Most human cancers express CD47 to escape the macrophage surveillance. To reinstate macrophage functionality in clearing tumor cells, targeting CD47 has been an important strategy in immune-oncology therapy. We profiled a large panel of tumor cell lines of both solid and blood tumors that are frequently used in cancer drug research and in Mixeno® animal study in Crown Bioscience for CD47. Despite its being reported as a ubiquitously expressed immune-escape marker in cancer cells, the expression levels of CD47 vary among different tumor cell lines when the cells were examined by flow cytometry. It is of interest that a portion of tumor cells in fact do not present CD47 despite gene expression data, such as RNA-seq data, suggesting that they do. To establish a robust and reproducible in vitro assay platform to support anti-CD47 drug research, we applied a macrophage differentiation system using isolated CD14+ monocytes as starting material, and were able to achieve > 80% of M1 and M2 populations, respectively, through the 6-day differentiation. Differentiated macrophage was cocultured with target tumor cells labeled for flow cytometry analysis. In the presence of anti-CD47 antibody, steady phagocytosis effect was observed with aCD47 BRIC126 antibody and target tumor cells expressing high level of CD47 markers. BRIC126 antibody blocks the CD47-SIRPalpha interaction. To prove the finding, we constructed isogenic cell models from the same parental cells in that CD47 gene is knocked out in one sub-cell line and overexpressed in another sub-cell line. The isogenic systems are also subject to the CD47 biology studies and can be served as positive and negative controls in phagocytosis assays. Detailed data will be discussed.

Citation Format: Huajun Yang, Zhongliang Li, Beibei Tang, Frank Xing, Qian Shi. CD47 expression predicts efficacy of macrophage-mediated phagocytosis of tumor cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B002.
Abstract B025: Purine biosynthesis regulates mTORC1 by modulating Rheb GTPase activity
Authors: Unsal-Kacmaz Kezi , Emmanuel Natasha , Ragunathan Shoba , Shan Qin , Wang Fang , Giannakou Andreas , Huser Nanni , Jin Guixian , Myers Jeremy , Abraham Robert T.
Published: August 2018

The mechanistic target of rapamycin complex 1 (mTORC1) regulates protein synthesis through effects on mRNA translation and ribosome biogenesis. Emerging evidence suggests that active mTORC1 also stimulates the de novo biosynthesis of purine and pyrimidine nucleotides. Here, using pharmacologic and genetic tools, we demonstrate that mTORC1 signaling is modulated by cellular purine nucleotide pools arising from the metabolic processes that generate ATP and GTP. Inhibition of GARFT, the enzyme that catalyzes the first folate-dependent step in purine synthesis, by the specific inhibitor AG2037, dramatically inhibits mTORC1 signaling via an AMPK-independent mechanism. GARFT inhibition suppresses the level of the activated form of the Rheb GTPase, a requisite upstream activator of mTORC1, through a global reduction in intracellular guanine-based nucleotides, and subsequently reduces Rheb protein farnesylation. Moreover, we demonstrate that mTORC1 blockade resulting from AG2037-mediated inhibition of GARFT impacts both translation initiation and pyrimidine biosynthesis and results in robust tumor growth inhibition of non-small cell lung cancer (NSCLC) xenografts. Our findings indicate that the regulatory relationship between mTORC1 activity and purine nucleotide pool is bidirectional, and suggest that mTORC1 inhibition contributes to the clinically established antiproliferative effects of purine biosynthesis inhibitors in cancer and inflammatory diseases.

Citation Format: Kezi Unsal-Kacmaz, Natasha Emmanuel, Shoba Ragunathan, Qin Shan, Fang Wang, Andreas Giannakou, Nanni Huser, Guixian Jin, Jeremy Myers, Robert T. Abraham. Purine biosynthesis regulates mTORC1 by modulating Rheb GTPase activity [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B025.
Abstract B038: Anaplastic lymphoma kinase addicted neuroblastoma cell lines are associated with growth upon treatment with MEK inhibitor trametinib
Authors: Hallberg Bengt , Umapathy Ganesh , Cervantes-Madrid Diana , Guan Jikui , Gustafsson Dan E. , Palmer Ruth H.
Published: August 2018

The RAS-RAF-MEK-ERK pathway is a major player in initiation and progression of multiple cancers where it can be hyper-activated by upstream regulatory proteins, such as tyrosine kinases, phosphatases, and GTPases. Several inhibitors targeting the RAS-MAPK pathway exhibit anticancer activity and are approved as single agent in specific cancers. One such is the MEK inhibitor trametinib, which is included as a rational poly therapy strategy for treating EML4-ALK, EGFR, and K-RAS mutant lung cancer and neuroblastoma containing hyper-activating RAS-MAPK pathway mutations. In neuroblastoma, a heterogeneous disease, relapse cases display an increased rate of mutations of ALK, NRAS, NF1 genes, leading to hyper-activation of RAS-MAPK signaling. Targeting the RAS-MAPK pathways offers attractive options for combinatorial treatment together with ALK inhibitors, since monotreatment has not yet produced strong clinical results in ALK-positive neuroblastoma patients. Here we investigate the response of ALK-positive neuroblastoma cell lines to MEK inhibition, employing trametinib. We show that pharmacologic inhibition of the MEK-ERK pathway in ALK-positive neuroblastoma cells results in increased levels of activation/phosphorylation of AKT and ERK5. This feedback response is regulated by the mTORC2 complex protein SIN1. Taken together, our results indicate that blocking MEK-ERK leads to "increased activation" of AKT signalling core in ALK-positive neuroblastoma, intensifying survival signals in these cells. Our results contraindicate use of MEK inhibitors as effective single and poly-therapeutic strategy in ALK-positive neuroblastoma.

Citation Format: Bengt Hallberg, Ganesh Umapathy, Diana Cervantes-Madrid, Jikui Guan, Dan E. Gustafsson, Ruth H. Palmer. Anaplastic lymphoma kinase addicted neuroblastoma cell lines are associated with growth upon treatment with MEK inhibitor trametinib [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B038.
Abstract B043: Mithramycin-SA analogues with reduced toxicity for the treatment of ETS transcription factor-driven tumors
Authors: Leggas Markos , Eckenrode Joseph , Mitra Prithiba , Jha Amit , Salem Shaimaa , Mandal Abhisek , Thorson Jon , Rohr Jurgen
Published: August 2018

Introduction: Chromosomal translocations involving the ETS family of transcription factors are common in Ewing sarcoma, prostate cancer, and leukemia. These translocations lead in overexpression of aberrant ETS transcription factors, which drive tumorigenesis. Mithramycin (MTM) inhibits EWS-FLI1, the most common ETS-related transcription factor in Ewing sarcoma, presumably through interference at its DNA binding sites on promoter regions. However, MTM has a narrow therapeutic window marked by severe liver and hematologic toxicities. These are likely the result of interference with the ubiquitously expressed SP1 transcription factor. Here, we sought to develop analogues with specificity toward ETS transcription factors and reduced interaction with SP1. Methods: Using MTM-SA and semisynthetic approaches a series of analogues were obtained. To determine specificity toward cells expressing ETS-related chromosomal translocations, MTM-SA analogues were screened for growth inhibition in a panel of Ewing sarcoma cell lines (n=8), all expressing EWS-ETS translocations, and compared to a panel of non-Ewing cell lines (n=9) that do not express these translocations. Luciferase reporter constructs were developed to evaluate interference with EWS-FLI1 and SP1 regulated genes following MTM-SA analogue treatment. Select analogues were tested in vivo to identify the maximum tolerated dose and determine pharmacokinetics (PK). Results: In growth inhibition assays, several MTM-SA analogues resulted in > 10-fold specificity toward Ewing sarcoma cell lines vs. MTM. Luciferase reporter assays identified two analogues, MTM-SA-Tryptophan-A2 and MTM-SA-Tryptophan-A10, with 10-fold reduced inhibition of SP1 but similar inhibition of EWS-FLI1, as compared to MTM. Additionally, MTM-SA-Phe analogue has lower toxicity, despite longer plasma half-life. Conclusion: These data show that MTM-SA analogues are cytotoxic against tumor cell lines expressing aberrant ETS transcription factors. Further, their reduced interference with the ubiquitously expressed SP1 transcription factor, as well as their improved PK, may result in a wider therapeutic window.

Citation Format: Markos Leggas, Joseph Eckenrode, Prithiba Mitra, Amit Jha, Shaimaa Salem, Abhisek Mandal, Jon Thorson, Jurgen Rohr. Mithramycin-SA analogues with reduced toxicity for the treatment of ETS transcription factor-driven tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B043.
Abstract B060: Small molecule inhibitor of pre-mRNA splicing evokes antitumor activity via MDM4-p53 pathway
Authors: Nishimura Kazuho , Yaguchi Masahiro , Yamamoto Yukiko , Ebara Shunsuke , Yoichi Kawakita , Mizojiri Ryo , Nakayama Yusuke , Hayashi Kozo , Miyakawa Shuichi , Iwai Kenichi , Nomura Toshiyuki
Published: August 2018

Proper control of gene expression at the level of transcription and RNA processing is a fundamental process of tumor cell growth. Here we showed that a novel pre-mRNA splicing modulator, Cdc2-like kinase (CLK) inhibitor T-025, suppressed tumor cell growth in vitro and in vivo. To reveal the mechanisms linking aberrant splicing and tumor growth suppression by T-025, we combined transcriptomic RNA-seq and proteomic p-SILAC data. We identified MDM4 as a mediator for triggering p53-dependent apoptosis in response to T-025. CLK inhibition led to exon 6 skipping of MDM4 mRNA, a potential target for nonsense-mediated decay, decreasing MDM4 protein. Consistent with these results, overexpression of MDM4 or knockdown of p53 attenuated growth-suppressive effects of T-025. We then investigated the relationship between genomic features and sensitivity to T-025 by evaluating the antiproliferative effect of T-025 against 240 cancer cell lines. Strikingly, expression of MDM4 was correlated with that of CLK2 and cell sensitivity to T-025. In addition, we found that copy number variation and mRNA expression of MYC were correlated with cell sensitivity to T-025. T-025 exhibited greater sensitivity in MYC-expressing cells and MYC-driven spontaneous breast cancer models. Together, we demonstrated that MDM4-p53 signaling and MYC-activation have key roles in antitumor activity of CLK inhibitor.

Citation Format: Kazuho Nishimura, Masahiro Yaguchi, Yukiko Yamamoto, Shunsuke Ebara, Kawakita Yoichi, Ryo Mizojiri, Yusuke Nakayama, Kozo Hayashi, Shuichi Miyakawa, Kenichi Iwai, Toshiyuki Nomura. Small molecule inhibitor of pre-mRNA splicing evokes antitumor activity via MDM4-p53 pathway [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B060.
Abstract B071: Detecting ultra low-frequency variants and fusions using a novel amplicon-based Accu-CometTM method
Authors: Wang Ling , Zhao Grace Q. , Weng Li , Chen Xiao , Li Min , Yang Xue , Zhao Jun , Wang Hongyan , Ying Kang , Faham Malek , Lin Shengrong , Lou Jiatao
Published: August 2018

We report the development of an ultra-accurate NGS technology, Accu-CometTM, which employs a concatemer-based error correction with amplicon workflow for the fast detection of low-frequency mutations including single-nucleotide variants (SNVs) and fusion events. We tested a non-small cell lung cancer (NSCLC) panel covering variants of EGFR, BRAF, and KRAS, as well as Alk fusion. Simulated cfDNA and cfDNA from healthy individuals were used to test the assay’s sensitivity and specificity. The analytic sensitivity of this panel was 100% detection at an allele frequency of 0.1% for 20ng of cf-DNA input. Similarly, the analytic sensitivity of the Alk fusion panel was 75% detection at an allele frequency of 0.1%, and 100% detection at an allele frequency of 0.25% for the same input. Clinical validation was performed via a comparative analysis of 171 NSCLC patients at different cancer stages and with different treatment plans. Among our patient cohort, 5 EGFR variants (19del, T790M, L858R, G719X, L861X) were detected. We also tested 47 noncancerous control samples and detected no false-positive variants at the reported cancer hot spots. Accu-CometTM demonstrated strong per-variant detection-rate concordance (> 96%) compared to ddPCR results, and >90% concordance when compared to tumor tissue ARMS result. The multiplex capacity, ultra sensitivity, and easy robust work flow of Accu-CometTM makes it well suited for supporting targeted therapy selection, drug resistance detection, and treatment monitoring.

Citation Format: Ling Wang, Grace Q. Zhao, Li Weng, Xiao Chen, Min Li, Xue Yang, Jun Zhao, Hongyan Wang, Kang Ying, Malek Faham, Shengrong Lin, Jiatao Lou. Detecting ultra low-frequency variants and fusions using a novel amplicon-based Accu-CometTM method [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B071.
Abstract B096: canSAR, a cancer research and drug discovery knowledgebase
Authors: Coker Elizabeth A. , Di Micco Patrizio , Tym Joesph E. , Mitsopoulos Costas , Komianou Angeliki , Antolin Albert A. , Al-Lazikani Bissan
Published: August 2018

canSAR (http://cansar.icr.ac.uk) is a freely available, multidisciplinary, cancer-focused knowledgebase developed to bring together information from genomic, transcriptomic, protein, pathway, chemical, pharmacologic, and 3D structural data. canSAR provides a powerful, uniqu,e and user-friendly portal to enable translational research and to help generate and test hypotheses and support scientific decision-making in drug discovery both before and after target selection. With its three alternative approaches to examine druggability, canSAR represents the most comprehensive public druggability assessment resource. canSAR provides 3D-structure-based druggability assessment for more than 3,100,000 cavities on more than 391,000 protein chains; ligand-based druggability assessment for 8,197 human proteins; and, more recently, protein network-based druggability results for 13,345 human proteins. Together these provide a powerful enabler for target selection and validation for drug discovery. Druggability assessments are presented alongside data from resources including 224,000 clinical trials from ClinicalTrials.gov, drug indications from Cancer.gov, target gene expression from TCGA for cell lines, and patient samples to provide a detailed picture of the target’s biologic context. Recent updates to canSAR include integration of ChEMBL 23 and additional curation of a protein-protein interaction network of 13,500 nodes. canSAR is currently used by more than 65,000 users annually from both academia and industry, and we will illustrate how canSAR can empower decision making in translational drug discovery.

Citation Format: Elizabeth A. Coker, Patrizio Di Micco, Joesph E. Tym, Costas Mitsopoulos, Angeliki Komianou, Albert A. Antolin, Bissan Al-Lazikani. canSAR, a cancer research and drug discovery knowledgebase [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B096.
Abstract B097: Dysregulated mevalonate and cholesterol synthesis is a therapeutic vulnerability in glioblastoma
Authors: Kambach Diane M. , Halim Alan S. , Cauer A. Gesine , Sun Qian , Tristan Carlos A. , Kesarwala Aparna H. , Shankavaram Uma , Batchelor Eric , Stommel Jayne M.
Published: August 2018

A hallmark of cellular transformation is the evasion of contact-dependent inhibition of growth. To find new therapeutic targets for glioblastoma, we looked for pathways that are inhibited by high cell density in normal astrocytes but have lost this regulation in glioblastoma stem-like cells. Here we report that at high cell density, normal astrocytes turn off mevalonate and cholesterol synthesis but glioma cells keep these pathways active. Correspondingly, mevalonate and cholesterol pathway upregulation is associated with poor prognosis in glioblastoma patients. Densely plated glioma cells increase oxygen consumption to synthesize cholesterol, resulting in a decrease in reactive oxygen species, TCA cycle intermediates, and ATP, but without a compensating increase in aerobic glycolysis. This constitutive cholesterol synthesis is controlled by the cell cycle, as it can be turned off by cyclin-dependent kinase inhibitors and it correlates with disabled cell cycle control though loss of p53 and RB. Mevalonate and cholesterol pathway activation promoted aberrant growth through the LXR and Hippo pathways. Finally, glioma cells, but not astrocytes, are sensitive to cholesterol synthesis inhibition downstream of the mevalonate pathway, suggesting that specifically targeting cholesterol synthesis might be an effective treatment for glioblastoma.

Citation Format: Diane M. Kambach, Alan S. Halim, A. Gesine Cauer, Qian Sun, Carlos A. Tristan, Aparna H. Kesarwala, Uma Shankavaram, Eric Batchelor, Jayne M. Stommel. Dysregulated mevalonate and cholesterol synthesis is a therapeutic vulnerability in glioblastoma [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B097.
Abstract B120: TAK-164, a GCC-targeted antibody-drug conjugate (ADC) for the treatment of colorectal cancers and other GI malignancies
Authors: Abu-Yousif Adnan O. , Bannerman Bret M. , Cvet Donna , Gallery Melissa , Ganno Michelle L. , Smith Michael D. , Lai Katharine C. , Keating Thomas A. , Bolleddula Jayaprakasam , Stringer Bradley , Qian Mark G. , Kamali Afrand , Eng Kurt , Koseoglu Secil , Xia Cindy Q. , Veiby O. Petter
Published: August 2018

TAK-164 is an antibody-drug conjugate comprising a full-length, fully human IgG1 monoclonal antibody (mAb) directed towards the extracellular domain of guanylyl cyclase C (GCC). The mAb is conjugated using the peptide-linked indolino-benzodiazepine DNA alkylator DGN549 (also known as IGN-P1). TAK-164 demonstrates efficient binding to antigen-expressing cells in vitro, and GCC-dependent uptake that results in cytotoxicity. Following a single administration of TAK-164 in female SCID mice bearing GCC-positive xenografts, the pharmacokinetics of the conjugated antibody component of TAK-164 displayed low plasma clearance. Exposure to the ADC resulted in a dose- and time-dependent increase in DNA damage as measured by the pharmacodynamic marker pH2A.X in GCC-positive tumor-bearing xenografts. To further these observations, antitumor activity of TAK-164 was evaluated in multiple GCC-positive patient-derived xenografts. In these studies, a single intravenous administration of TAK-164 resulted in durable antitumor activity. Furthermore, the use of preclinical imaging demonstrated that TAK-164 preferentially accumulates in GCC-positive tumors, and that treatment response can be monitored using FDG-PET. These promising preclinical data warrant advancement of this ADC to clinical evaluation.

Citation Format: Adnan O. Abu-Yousif, Bret M. Bannerman, Donna Cvet, Melissa Gallery, Michelle L. Ganno, Michael D. Smith, Katharine C. Lai, Thomas A. Keating, Jayaprakasam Bolleddula, Bradley Stringer, Mark G. Qian, Afrand Kamali, Kurt Eng, Secil Koseoglu, Cindy Q. Xia, O. Petter Veiby. TAK-164, a GCC-targeted antibody-drug conjugate (ADC) for the treatment of colorectal cancers and other GI malignancies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B120.
Abstract B125: A novel BBB-permeable chemotherapeutic agent for the treatment of CNS tumors
Authors: Nicolaides Theodore P. , Ozawa Tomoko , Yao Tsun Wen , Prados Michael , Fischer Wolf-Nicolas , Jandeleit Bernd , Koller Kerry
Published: August 2018

Standard of care for glioblastoma multiforme (GBM) patients is surgical tumor resection, followed by radiation and chemotherapy with temozolomide. Unfortunately, 60% of newly diagnosed GBM patients express high levels of the DNA repair enzyme MGMT and are temozolomide-insensitive, and all patients eventually become refractory to treatment. The blood-brain barrier (BBB) remains an obstacle to adequate delivery of chemotherapeutic agents to brain tumors. Lipophilic drugs such as temozolomide and lomustine are able to cross the BBB based on passive diffusion; however, their tissue distribution also causes toxicity to critical systemic organs, such as the bone marrow, leading to dose-limiting toxicity. Therefore, BBB-permeable chemotherapeutic agents that are efficacious in temozolomide-insensitive and refractory patients are needed. The large amino acid transporter 1 (LAT1) is highly expressed on the BBB and in GBM and other malignant brain tumors such as diffuse intrinsic pontine glioma (DIPG), where it is associated with poor prognosis, but is undetectable in normal brain tissue. Targeting LAT1 transport, while avoiding interaction with other closely related transporters expressed on normal tissue such as LAT2, will target brain tumors and avoid uptake into healthy tissue. We report the generation of a novel molecule (QBS10072S) that combines a potent cytotoxic domain with the structural features of a selective LAT1 substrate. QBS10072S is 50-fold more selective for LAT1 vs. LAT2 in transport assays, and demonstrates significant in vitro cytotoxicity to LAT1-expressing GBM cell lines and minimal cytotoxicity to normal human astrocytes (LAT1-negative). Unlike temozolomide, QBS10072S is cytotoxic to cells with both high and low levels of MGMT expression. In orthotopic glioblastoma xenografts, QBS10072S causes significant delay in tumor growth and increase in mouse survival compared to vehicle. QBS10072S is well tolerated, with no toxicity seen in normal brain or the BBB. In summary, QBS10072S is a novel BBB-permeable chemotherapeutic agent with the potential to treat temozolomide-insensitive and recurrent GBM.

Citation Format: Theodore P. Nicolaides, Tomoko Ozawa, Tsun Wen Yao, Michael Prados, Wolf-Nicolas Fischer, Bernd Jandeleit, Kerry Koller. A novel BBB-permeable chemotherapeutic agent for the treatment of CNS tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B125.
Abstract B150: ASN007, a novel oral ERK inhibitor, shows robust antitumor activity in RAS mutant cancer models
Authors: Reddy Sanjeeva P. , Sivanandhan Dhanalakshmi , Dewang Purushottam , Rao Niranjan , Smith Roger A. , Thompson Scott K.
Published: August 2018

The extracellular-signal-regulated kinases, ERK1 and ERK2 (ERK1/2), are key players in the RAS/RAF/MEK signaling pathway. This pathway is frequently hyper-activated in a wide range of cancers through mutations in upstream targets such as BRAF, RAS, and receptor tyrosine kinases. Inhibition of ERK1/2 offers a promising therapeutic strategy for these cancers, particularly the ones driven by RAS mutations. In order to inhibit this critical node of the RAS/RAF/MEK pathway, we discovered and characterized ASN007, a novel compound that shows potent inhibition of ERK1/2 kinases in a biochemical assay with low single-digit nM IC50 values. ASN007 showed a slow dissociation rate (long target residence time) as compared to several other known ERK inhibitors. In mechanistic cell-based assays, ASN007 inhibited the phosphorylation of ERK1/2 substrates such as RSK1, FRA1, and Elk1 in various cell lines. ASN007 showed single-digit nanomolar antiproliferative activity that was selective for MAPK-pathway dependent cancer cell lines. Indeed, ASN007 showed much more potent activity against a broader panel of KRAS, NRAS, and HRAS mutant cell lines compared to other ERK1/2 inhibitors such as BVD-523 and GDC-0994. In a daily oral dosing regimen, ASN007 demonstrated strong inhibition of tumor growth in multiple BRAF and KRAS mutant xenograft models in mice and was well tolerated at efficacious doses. Of note, ASN007 also showed strong efficacy using various intermittent dosing regimens. ASN007 has a good pharmacokinetic profile in preclinical species and does not exhibit significant inhibition of CYP enzymes or hERG channel. IND-enabling studies are ongoing in preparation for a phase 1 clinical trial to evaluate oral ASN007 in patients with BRAF and K- , H- , and N-RAS mutant cancers

Citation Format: Sanjeeva P. Reddy, Dhanalakshmi Sivanandhan, Purushottam Dewang, Niranjan Rao, Roger A. Smith, Scott K. Thompson. ASN007, a novel oral ERK inhibitor, shows robust antitumor activity in RAS mutant cancer models [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B150.
Abstract B177: Synthetic lethal approach identifies potent and selective TTK and CLK inhibitor with preclinical anticancer activity in triple-negative breast cancer model
Authors: Zhu Dan , Deyanat-Yazdi Gordafaried , Mikolon David , Narla Rama K. , Peng Sophie X. , Ning Yuhong , Riggs Jennifer R. , Boylan John F.
Published: August 2018

Historically, synthetic lethal-based drug discovery has yielded a high percentage of novel, first-in-class drugs while uncovering new tumor biology. Using a synthetic lethal approach, we identified one compound that preferentially induced apoptosis in triple-negative breast cancer (TNBC) cell lines while sparing luminal breast cancer cell lines. The synthetic lethal approach evolved into a targeted approach following the identification of the two kinases that were selectively inhibited by CC-671 in enzyme assays: human protein kinase monopolar spindle 1 (hMps1), also known as TTK, and CDC2-like kinase (CLK2). Detailed CC-671 cellular mechanism of action studies showed phosphorylation inhibition of the direct substrates of TTK and CLK2. The CC-671 IC50 concentration that inhibited phosphorylation of the CLK2 substrate SR protein ranged between 530 and 553 nM in CAL51 cells. Gene Set Enrichment Analyses (GSEA) of RNAseq data suggest that CC-671 CLK2 inhibition induces apoptosis by reducing expression of antiapoptotic isoforms via splicing modification. Cellular CC-671 TTK inhibition was demonstrated by significant reduction of TTK autophosphorylation at T686 and phosphorylation of KNL1, one of the well-characterized TTK substrates. CC-671 treatment also led to a decrease of cyclin B and securin protein level. As a result, the percentage of mitotic cells in nocodazole-arrested CAL51 cells was substantially reduced by CC-671. Furthermore, data from time-lapse video microscopy experiments confirmed the mitotic phase length was reduced by approximately half upon CC-671 treatment. Inhibition of phospho-Histone H3 (Ser 10) following a single CC-671 administration was observed in TNBC in vivo tumor model. More importantly, significant CC-671 in vivo efficacy was demonstrated in a cell line-derived TNBC xenograft model with weekly dosing. The data described here suggest that dual inhibition of TTK and CLK2 represents an attractive therapeutic approach for triple-negative breast cancer. CC-671 presents a unique profile for an anticancer kinase inhibitor.

Citation Format: Dan Zhu, Gordafaried Deyanat-Yazdi, David Mikolon, Rama K. Narla, Sophie X. Peng, Yuhong Ning, Jennifer R. Riggs, John F. Boylan. Synthetic lethal approach identifies potent and selective TTK and CLK inhibitor with preclinical anticancer activity in triple-negative breast cancer model [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B177.