bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B157: Effect of HGF concentration on c-Met phosphorylation and inhibition in paracrine-activated tumor cells
Authors: Hughes Veronica S. , Siemann Dietmar W.
Published: August 2018

c-Met is a receptor tyrosine kinase critical for embryogenesis and liver repair. In tumors, including breast, prostate, glioblastoma, and thyroid cancer, Met protein levels are often elevated and associated with disease progression and metastasis. The c-Met pathway is activated by the endogenous ligand hepatocyte growth factor (HGF). HGF is produced by mesenchymal cells and binds to the c-Met protein, leading to phosphorylation and upregulation of a variety of downstream signaling pathways that result in increased tumor cell migration, proliferation, survival, and induction of angiogenesis. Consequently, there has been significant interest in the development of c-Met inhibitors as anticancer therapeutics. The efficacy of such agents usually initially are determined in vitro utilizing HGF concentrations of 25-50 ng/mL. However, HGF serum levels in humans typically range from 0.4-0.8 ng/mL. To examine the impact of exogenous HGF levels on c-Met inhibitor activity, human prostate (PC-3, DU145) and lung (A549) cancer cell lines were utilized in this study. These cell lines have been previously characterized as paracrine-activated: cell lines that express the c-Met receptor, but not HGF. In the presence of 25-50 ng/mL HGF, these cell lines demonstrated a reduction in migration, invasion, and phosphorylation of Met after treatment with the small-molecule c-Met inhibitor BMS-777607. However, such antitumor efficacy was absent when these paracrine-activated cell lines were treated with BMS-777607 in the presence of physiologically normal concentrations of HGF (0.4-0.8 ng/mL). A human HGF-expressing mouse model has been developed for xenograft studies of human c-Met inhibition, on the basis that mouse HGF does not activate human c-Met. However, we found that mouse HGF was able to induce phosphorylation of Met in the human DU145 cell line. In vivo, DU145 xenografts in NSG mice treated with BMS-777607 showed no reduction in c-Met phosphorylation unless the mice were administered exogenous HGF during tumor growth. Taken together, these findings indicate that the utilization of nonphysiologic concentrations of HGF in tissue culture evaluations of c-Met targeting agents may result in an overestimation of agent activity not likely to be observed in the tumor microenvironment.

Citation Format: Veronica S. Hughes, Dietmar W. Siemann. Effect of HGF concentration on c-Met phosphorylation and inhibition in paracrine-activated 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 B157.
Abstract B162: Highly selective, orally available CDK7 inhibitor for cancer therapy
Authors: Jeon Yeejin , Yu Donghoon , Seo Mooyoung , Kim June , Shin Jaehee , Kang Hwankyu , Ahn Jiye , Choi Jinho , Ahn Seohyun , Kim Jaeseung , Nam Kiyean
Published: August 2018

Cyclin-dependent kinase 7 (CDK7) has dual functions in cell: 1) CDK-activating kinase (CAK) that regulates cell cycle progression by phosphorylation of CDK1, CDK2, and CDK4/6, and 2) a component of transcription factor II H (TFIIH) that regulates transcriptional initiation through phosphorylation of RNA polymerase II C-terminal domain (CTD). Here we present orally available, selective CDK7 inhibitors that show distinct mechanism of action in different cancer cell lines. In some cell lines, compounds exert anti-CAK activity leading to cell cycle arrest, and in others, show transcription inhibitor activity leading to apoptosis. The differential roles of CDK7 seem to be a basis for good specificities of selective CDK7 inhibitors in cancer cell line panel, showing big difference in cytotoxic activity between responding and nonresponding cells. Lead compounds have been optimized for drug-like properties, high potency, and good selectivity and desirable pharmacokinetic profile to achieve antitumor activity. The lead compound shows good activity in mouse models through oral administration without gross adverse findings. Final optimization is under way for candidate nomination.

Citation Format: Yeejin Jeon, Donghoon Yu, Mooyoung Seo, June Kim, Jaehee Shin, Hwankyu Kang, Jiye Ahn, Jinho Choi, Seohyun Ahn, Jaeseung Kim, Kiyean Nam. Highly selective, orally available CDK7 inhibitor for cancer therapy [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 B162.
Abstract B163: Identification and preclinical characterisation of VER-250840, a potent, selective Chk1 inhibitor with in vivo oral single-agent antitumor activity
Authors: Wayne Joanne , Stokes Stephen , Foloppe Nicolas , Browne Helen , Brooks Teresa , Benwell Karen , Baker Lisa , Daniels Zoe , Fiumana Andrea , Graham Christopher , Macias Alba , Maddox Daniel , McKenna Sean , Northfield Christopher , Ray Stuart , Simmonite Heather , Stefaniak Emma , Webb Paul , Wood Mike , Massey Andrew
Published: August 2018

On sustaining damage to their DNA, cells employ a sophisticated mechanism of detection and repair, termed the DNA damage response (DDR). As a critical component of the DDR and G2/M checkpoint, Chk1 kinase represents an attractive target for cancer therapy. We have utilized a structure-based drug design approach to identify and develop VER-250840, a novel, orally active inhibitor of the checkpoint kinase, Chk1. VER-250840 exhibited sub-nM potency against Chk1 kinase with exquisite selectivity over an extensive and diverse panel of kinases. In vitro, VER-250840 inhibited Chk1 autophosphorylation with an IC50 of 1.0 nM and increased the number of S-phase tumor cells staining positive for pan-nuclear γH2AX with an EC50 of 7 - 27 nM. Accumulated genomic DNA damage by Chk1 inhibition led to irreversible cell cycle arrest, inhibition of tumor cell proliferation, increased replication stress, and cell death in both 2D culture and multicellular tumor spheroids. In an in vivo A2058 tumor xenograft PD study, VER-250840 demonstrated rapid and sustained inhibition of Chk1 auto-phosphorylation within 30 minutes of oral administration. Doses of 10 mg/kg and higher PO resulted in greater than 90% inhibition of tumor pChk1 (S296) over 24 hours. In SKOV3 in vivo models, VER-250840 inhibited Chk1 auto-phosphorylation, modulated other biomarkers of replication stress and DNA damage, and exhibited moderate antitumor activity with minimal toxicity when administered orally on a 21-day once-daily schedule. Work is ongoing to further optimize in vivo efficacy. In conclusion, VER-250840 demonstrates potent and selective activity as a monotherapy both in vitro and in vivo. From these findings, further evaluation and optimization of this novel kinase inhibitor is justly merited.

Citation Format: Joanne Wayne, Stephen Stokes, Nicolas Foloppe, Helen Browne, Teresa Brooks, Karen Benwell, Lisa Baker, Zoe Daniels, Andrea Fiumana, Christopher Graham, Alba Macias, Daniel Maddox, Sean McKenna, Christopher Northfield, Stuart Ray, Heather Simmonite, Emma Stefaniak, Paul Webb, Mike Wood, Andrew Massey. Identification and preclinical characterisation of VER-250840, a potent, selective Chk1 inhibitor with in vivo oral single-agent antitumor 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 B163.
Abstract B185: TPX-0005, a supreme ROS1 inhibitor, overcomes crizotinib-resistant ROS1 mutations including solvent front mutation G2032R and gatekeeper mutation L2026M
Authors: Cui J. Jean , Zhai Dayong , Deng Wei , Rogers Evan , Huang Zhongdong , Whitten Jeffrey , Lim John , Li Yishan
Published: August 2018

The fusion kinases of ROS1 and ALK have been identified as oncogene drivers in small portions of many malignancies, especially in non-small cell lung cancer (NSCLC). ALK/ROS1/MET inhibitor crizotinib has been approved by the US Food and Drug Administration for the treatment of ALK or ROS1-positive non-small cell lung cancer in 2011 and 2016, respectively. The emergence of drug resistance presents a major issue for targeted therapy. Although ceritinib, alectinib, and brigatinib have been approved for crizotinib-refractory ALK+ patients with NSCLC, treatment options for patients with ROS1+ NSCLC are limited, especially for crizotinib-refractory patients. Ceritinib and entectinib demonstrated clinical efficacy only in crizotinib-naïve ROS1+ patients. The most common resistance mechanisms to crizotinib treatment in ROS1+ NSCLC is the solvent front mutation ROS1 G2032R and gatekeeper mutation ROS1 L2026M. TPX-0005, a novel three-dimensional macrocycle with a much smaller size than current ROS1 inhibitors in the clinic, was designed to overcome clinical resistance mutations systematically. TPX-0005 potently inhibited both wild type and mutant ROS1s including solvent front mutations and gatekeeper mutations. TPX-0005 showed pico-molar activity against ROS1 kinase (IC50 0.076 nM) in Reaction Biology kinase assay. The comparison of TPX-0005 with other ROS1 inhibitors in Ba/F3 cell proliferation assays is presented in the table. In the xenograft tumor model studies, TPX-0005 dramatically caused tumor regression in the tumors carrying WT or solvent-front mutated ROS1 fusion gene. Overall, TPX-0005 demonstrated desired drug-like properties, good safety profile, and is a supreme ROS1 inhibitor against WT and various mutated ROS1s. A phase 1/2 clinical trial of TPX-0005 is actively being pursued (NCT03093116). CD74-ROS1 Ba/F3 Cell Proliferation Assay IC50 (nM)InhibitorWTG2032RD2033NL2026MS1986FS1986YTPX-0005<0.28.40.210<0.2<0.2Crizotinib9.71402139606.420.919Lorlatinib0.5262.42.4ND0.30.3Entrectinib25.42404ND2026NDNDCeritinib131.92000NDND14.226.9Brigatinib28.61385167.1211527.724.6Cabozantinib1.060.70.129.1NDND

ND: not determined.

Citation Format: J. Jean Cui, Dayong Zhai, Wei Deng, Evan Rogers, Zhongdong Huang, Jeffrey Whitten, John Lim, Yishan Li. TPX-0005, a supreme ROS1 inhibitor, overcomes crizotinib-resistant ROS1 mutations including solvent front mutation G2032R and gatekeeper mutation L2026M [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 B185.
Abstract B192: The EPR effect of CDP-tubulysin in the recurrence of lung and pancreatic cancers
Authors: Tsai Pei-Yi , Jheng Huei-Lin , Hsieh Yen-Ju , Tsai Yung-Jen , Ahrweiler Michael , Richter Wolfgang , Abbas Muhammad , Pasut Gianfranco , Chang Jia-Ming
Published: August 2018

Tubulysins, a tubulin-targeted class of natural compounds, are highly active in multidrug-resistant cells and potential agents to overcome clinical drug resistance in recurrent tumors. Unfortunately, the extraordinary activity of the potent tubulysins poses considerable complications for chemotherapeutic applications due to toxicity against normal cells and tissues. Nanoparticle drug delivery systems provide the potential to increase the intracellular concentration of drugs in cancer cells while avoiding toxicity in normal cells through the enhanced permeability and retention (EPR) effect. In this study, the efficacy of β-cyclodextrin-based polymeric tubulysin (CDP-tubulysin) administered by intravenous injection was tested on subcutaneous lung and pancreatic xenograft models. The single-dose pharmacokinetic study and tumor distribution of CDP-tubulysin and tubulysin alone were also determined in tumor-bearing mice. Our data demonstrated that CDP-tubulysin showed potent efficacy in treating lung and pancreatic cancers. The recurrent lung and pancreatic tumors were also regressed by treating with CDP-tubulysin but not gemcitabine. Moreover, the conjugation of CDP to tubulysin showed control-release behavior in the blood resulting in increased distribution of tubulysin in tumors. In conclusion, CDP conjugation was an effective delivery of tubulysins to avoid toxicity and provide potency in recurrent tumors through the EPR effect.

Citation Format: Pei-Yi Tsai, Huei-Lin Jheng, Yen-Ju Hsieh, Yung-Jen Tsai, Michael Ahrweiler, Wolfgang Richter, Muhammad Abbas, Gianfranco Pasut, Jia-Ming Chang. The EPR effect of CDP-tubulysin in the recurrence of lung and pancreatic cancers [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 B192.
Abstract B202: Covalent irreversible usp7 inhibitors for cancer immunotherapy
Authors: Kumar Suresh , Wu Jian , Wang Feng , Wang Liqing , Chen Lee , Sokirniy Ivan , Wang Hui , Sterner David , Grove Charles , Cunnion Brigid , Weinstock Joseph , Mattern Michael , Hancock Wayne
Published: August 2018

Tumors employ diverse strategies to suppress and evade the immune system’s ability to recognize and destroy tumor cells. Immune-suppressive Foxp3+ regulatory T cells (Tregs) in the tumor microenvironment correlate with poor prognosis in solid tumors. Therefore, selective depletion of tumor-associated Tregs or impairment of Treg function is considered an attractive cancer immunotherapy approach. The pro-tumorigenic deubiquitylase (DUB) USP7 is also essential for Treg functions. USP7 controls Treg function largely by regulating post-translational modification of Foxp3 and TIP60. Deletion of USP7 in Tregs results in impairment of Treg functions and autoimmunity in mice. Progenra has developed potent, selective covalent irreversible USP7 inhibitors that impair Treg functions ex vivo and in vivo. Most importantly, USP7 inhibitors exhibit robust antitumor activity against several syngeneic solid tumor models in immunocompetent mice. In addition, Progenra’s USP7 inhibitors enhance the efficacy of anti-PD1 antibody, anti-CTLA4 antibody, and cancer vaccines. These studies strongly suggest that USP7 inhibitors alone or in combination regimens can improve the efficacy and expand the scope of cancer immunotherapy.

Citation Format: Suresh Kumar, Jian Wu, Feng Wang, Liqing Wang, Lee Chen, Ivan Sokirniy, Hui Wang, David Sterner, Charles Grove, Brigid Cunnion, Joseph Weinstock, Michael Mattern, Wayne Hancock. Covalent irreversible usp7 inhibitors for cancer immunotherapy [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 B202.
Abstract B203: Heterogeneity in androgen receptor and IL-1beta expression by prostate cancer cells in skeletal metastases
Authors: Worrede-Mahdi Asurayya A. , Fatatis Alessandro
Published: August 2018

Bone metastases are a prevalent complication of advanced prostate cancer (PCa). The current standard of care for advanced PCa patients is androgen deprivation therapy (ADT), which fails within approximately two years and patients progress to castration-resistant prostate cancer (CRPC). CRPC presents with additional metastasis in soft tissues and is incurable. We have found that in PCa patients, bone metastases have heterogeneous androgen receptor (AR) expression, and that cells lacking AR are the only cell type that secretes the cytokine Interleukin-1 beta (IL-1β). Furthermore, preclinical work in our lab has revealed the role for IL-1β in promoting bone colonization by AR+ PCa cells and generation of heterogeneous skeletal metastases. A significant barrier to studying tumor heterogeneity in PCa metastasis has been the lack of an animal model to study the interaction between multiple PCa phenotypes in the bone microenvironment. By engrafting a suspension containing both AR− and AR+ cells directly into the left cardiac ventricle of mice, our lab has developed an in vivo model that allows us to study the progression of both AR− and AR+ cells in skeletal and soft tissue metastases. AR− and AR+ cells were genetically engineered to express two different Luciferase constructs (630 nm Red-shifted Luc and 540 nm Luc2, respectively) thereby allowing the progression of AR− and AR+ cells to be independently tracked and quantified. We used this model in combination with histologic and radiographic analyses to assimilate the pathologic features of our in vivo mixed AR+/AR− metastases to the human clinical scenario. Finally, we used castrated mice to determine whether IL-1β secreting PCa cells could support the growth and survival of IL-1β-/AR+ cells in androgen-deprived conditions. Coinjection of AR− (PC3-ML) and AR+ cells (LNCaP, VCaP, and 22Rv1) leads to increased establishment of soft tissue metastases as compared to injecting AR− cells alone. Unlike the metastases generated by PC3-ML cells alone, which show exclusively osteolytic activity, AR−/AR+ mixed metastases are both osteosclerotic and osteolytic, thereby recapitulating clinical pathology. Finally, preliminary results suggest that coinjection with IL-1β-secreting AR− cells enables the growth of androgen-dependent AR+ cells in castrated mice. This animal model of metastasis heterogeneity recapitulates human pathology and enables further interrogation of the mechanism by which IL-1β supports survival of AR+ cells and the potential role for AR− in evading AR-targeted therapy during CRPC.

Citation Format: Asurayya A. Worrede-Mahdi, Alessandro Fatatis. Heterogeneity in androgen receptor and IL-1beta expression by prostate cancer cells in skeletal metastases [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 B203.
Abstract B205: Intervenolin suppresses gastric cancer cell growth via stromal secreted factors
Authors: Yoshida Junjiro , Abe Hikaru , Watanabe Takumi , Kawada Manabu
Published: August 2018

Background: Tumor-stromal cell interactions are attractive targets for cancer chemotherapy because fibroblast-like stromal cells modulate cancer cells both positively and negatively through secreted factors as well as proteins of the extracellular matrix. We have focused on the negative regulation of cancer cells by secreted factors of stromal cells as it offers a novel strategy for discovering new cancer therapeutics. We used a coculture system to screen small molecules from natural sources such as microbial culture media, seeking molecules that modulated tumor-stromal cell interactions. In a recent study, we found a novel compound, intervenolin (ITV), from the culture medium of Nocardia sp. ML96-86F2. ITV inhibited the in vitro growth of human gastric cancer cells. Importantly, inhibition was greater when the cancer cells were cocultured with stromal cells. Here we report the mechanism of ITV action. Materials and Method: Human gastric cancer MKN-7 and MKN-74 cells were cultured with human gastric stromal Hs738 cells in the presence of ITV. The growth of MKN-7 and MKN-74 cells cultured in only CM taken from Hs738 cells treated with ITV (ITV CM) was also inhibited more strongly than it was cultured alone. We prepared serum-free CM from Hs738 cells to determine the anticancer factors secreted by ITV-treated HS738 cells using LC-MS/MS analysis. Results: Conditioned medium (CM) of ITV-treated Hs738 cells inhibited the growth of MKN-7 or MKN-74 cells and suppressed c-MYC protein level in MKN-74 cells. This result suggested that ITV induced the negative modulation of cancer cells through secreted factors from stromal cells. Proteome analysis of ITV-treated Hs738 CM revealed that one of the candidates could be thrombospondin-1 (TSP-1). As a result, recombinant TSP-1 inhibited the growth of gastric cancer cells and downregulated c-MYC. Conclusions: ITV inhibits gastric cancer cell growth through inducing TSP-1 secretion from Hs738 cells in coculture system in vitro. No conflict of interest.

Citation Format: Junjiro Yoshida, Hikaru Abe, Takumi Watanabe, Manabu Kawada. Intervenolin suppresses gastric cancer cell growth via stromal secreted factors [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 B205.
Abstract B212: N-myc downstream regulated 1 (NDRG1) is regulated by eukaryotic initiation factor 3a (eIF3a) during cellular stress caused by iron depletion
Authors: Paluncic Jasmina , Lane Darius J. R. , Saletta Federica , Rahmanto Yohan S. , Kovacevic Zaklina , Richardson Des R.
Published: August 2018

Iron is critical for cellular proliferation and its depletion leads to a suppression of both DNA synthesis and global translation. These observations suggest that iron depletion may trigger a cellular “stress response.” A canonical response of cells to stress is the formation of stress granules, which are dynamic cytoplasmic aggregates containing stalled preinitiation complexes that function as mRNA triage centers. By differentially prioritizing mRNA translation, stress granules allow for the continued and selective translation of stress response proteins. Although the multi-subunit eukaryotic initiation factor 3 (eIF3) is required for translation initiation, its largest subunit, eIF3a, may not be essential for this activity. Instead, eIF3a is a vital constituent of stress granules and appears to act, in part, by differentially regulating specific mRNAs during iron depletion. Considering this, we investigated eIF3a’s role in modulating iron-regulated genes/proteins that are critically involved in proliferation and metastasis. In this study, eIF3a was downregulated and recruited into stress granules by iron depletion as well as by the classical stress inducers, hypoxia and tunicamycin. Iron depletion also increased expression of the metastasis suppressor, N-myc downstream regulated gene-1 (NDRG1), and a known downstream repressed target of eIF3a, namely the cyclin-dependent kinase inhibitor, p27kip1. To determine if eIF3a regulates NDRG1 expression, eIF3a was inducibly overexpressed or ablated. Importantly, eIF3a positively regulated NDRG1 expression and negatively regulated p27kip1 expression during iron depletion. This activity of eIF3a could be due to its recruitment to stress granules and/or its ability to differentially regulate mRNA translation during cellular stress. Additionally, eIF3a positively regulated proliferation, but negatively regulated cell motility and invasion, which may be due to the eIF3a-dependent changes in expression of NDRG1 and p27kip1 observed under these conditions.

Citation Format: Jasmina Paluncic, Darius J. R. Lane, Federica Saletta, Yohan S. Rahmanto, Zaklina Kovacevic, Des R. Richardson. N-myc downstream regulated 1 (NDRG1) is regulated by eukaryotic initiation factor 3a (eIF3a) during cellular stress caused by iron depletion [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 B212.
Abstract LB-A02: Oncoyeasti: a web-based application to translate data obtained from yeast high-throughput drug screens into cancer therapeutics
Authors: Gupta Ruby , Anand Nikhilesh , Cayenne Samir , Otohinoyi David , Talukdar Debjyoti , Patil Ashish
Published: August 2018

The budding yeast (Saccharomyces Cerevisiae) and Fission yeast (Saccharomyces Pombe) gene deletion libraries are a useful tool for high throughput screening of anti-cancer drugs. But using the data derived by high-throughput screening of yeast library to identify corresponding human homologs and their status in various human cancers is a cumbersome process. We have developed a web based application called Oncoyeasti, that enables the researcher to automatically identify the corresponding human homologs of S Cerevisiae and S Pombe genes and the status of these homolog genes in more than 45000 tumor sample datasets of The Cancer Genome Atlas (TCGA) Database and the cancer cell lines datasets present in Cancer Cell Line Encyclopedia. We used server side scripting language PHP for web development platform along with MYSQL interface for matching the input S. Cerevisiae or S. Pombe genes with the corresponding Human Homologs and generate an URL link for the cBio Cancer Genomics Portal, used to navigate TCGA Database and CCLE databases. Our web based application has the capability to analyze up to 100 S. Cerevisiae or S. Pombe genes at once. This would enable the scientists to translate their research from yeast to humans by identifying the human cancers and cancer cell lines in which the human homologs of the corresponding yeast genes are perturbed.

Citation Format: Ruby Gupta, Nikhilesh Anand, Samir Cayenne, David Otohinoyi, Debjyoti Talukdar, Ashish Patil. Oncoyeasti: a web-based application to translate data obtained from yeast high-throughput drug screens into cancer therapeutics [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 LB-A02.
Abstract LB-A04: Transcriptional regulatory programs in gynecological cancers
Authors: Osmanbeyoglu Hatice U. , Jelinic Petar , Levine Douglas , Leslie Christina S.
Published: August 2018

Cancer cells acquire genetic and epigenetic alterations that often lead to dysregulation of oncogenic signal transduction pathways, which in turn alter downstream transcriptional programs. The Cancer Genome Atlas (TCGA) has studied several of the most common and aggressive gynecologic tumors including high-grade serous ovarian carcinomas (HGSOC), uterine carcinosarcoma (UCS), and the serous-like subset of endometrial cancer (UCEC), together with basal breast cancer, which shares many genomic features with serous ovarian tumors. These tumors all lack accurate predictors of response and resistance and share an unmet need for adequate treatment of recurrent disease. We developed a multitask learning framework for integrating regulatory sequence from ATAC-mapped promoters and enhancers with RNA-seq data from patient tumors in order to infer transcription factor (TF) regulatory activities and explore similarities and differences between endometrial, ovarian, and basal breast tumors. We showed that our multitask learning framework enables us to selectively share the information across tumors and strongly improves the accuracy of gene expression prediction models for gynecological and basal breast tumors. Our analysis identified histologic type specific and common TF regulators of gene expression as well as predicted distinct dysregulated transcriptional regulators downstream of somatic alterations in these different cancers. Moreover, many of the identified TF regulators were significantly associated with survival outcome within the histological subtype. Computationally dissecting the role of TFs in these cancers may ultimately lead to new therapeutics tailored to subtype or individual.

Citation Format: Hatice U. Osmanbeyoglu, Petar Jelinic, Douglas Levine, Christina S. Leslie. Transcriptional regulatory programs in gynecological cancers [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 LB-A04.
Abstract LB-A07: Clinical utility of genomic assessment of blood-derived circulating tumor (ctDNA) in patients with colorectal cancers
Authors: Schwaederle Maria C. , Kato Shumei , Choi In Sil , Fanta Paul T. , Leichman Lawrence , Lippman Scott , Kurzrock Razelle
Published: August 2018

Background: Genomic alterations in blood-derived circulating tumor DNA (ctDNA) from patients with colorectal cancers (CRC) were correlated with clinical characteristics and therapeutic outcomes.

Methods: Plasma ctDNA testing (54-73 genes; all non-synonymous alterations are analyzed herein) was performed in 94 patients with CRC (PREDICT-UCSD; NCT02478931).

Results: Ninety-six percent of patients had metastatic or recurrent disease at the time of blood draw. The median number of alterations/patient was 3 (range, 0-30). The most frequent alterations involved TP53 (52.1%), KRAS (34%), and APC (28.7%) genes; no two patients had identical molecular portfolios. Altogether, 74 patients (79%) had ≥ 1 alteration; 69 patients (93% of patients with ≥ 1 detectable ctDNA alteration) had ≥ 1 actionable alteration; 61 patients had an alteration actionable by an FDA-approved drug (on or off-label). Concordance between ctDNA and tissue genomics for the most frequent genes altered in ctDNA ranged from 63% to 86%, depending on the gene (median ~6 months between samples). Improved survival (multivariate) correlated with lung metastasis and with all ctDNA alteration fractions < 5%. To date, 35 patients (median of one prior therapy in the metastatic setting) were treated with matched (N = 18) or unmatched (N = 17) therapy after ctDNA testing. Overall, 67% versus 27% of patients (matched vs unmatched) achieved SD ≥ 6 months/PR/CR (P=0.02); PFS of 6.1 vs 2.3 months (P = 0.08); OS (13.2 vs 5.1 months; not significant) (all multivariable). In serial samples from patients on anti-EGFR therapy, multiple emerging alterations in genes known to be involved in therapeutic resistance, including KRAS, NRAS, BRAF, EGFR, ERBB2, and MET were detected.

Conclusion: Most patients demonstrated potentially actionable ctDNA alterations. Improved outcomes were associated with lung metastases and low ctDNA percentage. Treatment with matched therapy correlated with significantly higher rates of SD ≥ 6 months/PR/CR (67% vs 27%). Dynamic changes in ctDNA were evident after anti-EGFR treatment, with emergence of resistance mutations, some of which may be druggable. Larger studies in CRC and other malignancies are ongoing.

Citation Format: Maria C. Schwaederle, Shumei Kato, In Sil Choi, Paul T. Fanta, Lawrence Leichman, Scott Lippman, Razelle Kurzrock. Clinical utility of genomic assessment of blood-derived circulating tumor (ctDNA) in patients with colorectal cancers [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 LB-A07.
Abstract LB-A21: PRAS40 (AKT1S1) ablation modulates breast cancer by increasing tumor-free survival in HER-2/neu overexpressing mice
Authors: Malla Ritu , Faridi Jesika S.
Published: August 2018

HER-2 is over-expressed in around 20% of breast cancer patients and is correlated with a shorter relapse time and poor prognosis. This makes it crucial to identify novel downstream molecular targets in spite of a number of clinically approved drugs that target HER-2. In this study, we determined if loss of proline-rich Akt substrate of 40 kDa (PRAS40) gene increases tumor-free survival in HER-2/neu over-expressing double transgenic mice. Tumor kinetics was determined in HER-2 overexpressing PRAS40+/+ (wild-type) versus PRAS40-/- (knock-out) mice. Mammary intraepithelial neoplasias (MINs or precancerous lesions) in mammary tissues were analyzed using whole mount analysis. We observed significant increase of tumor-free survival in HER-2 overexpressing PRAS40-/- versus PRAS40+/+ parous female mice, however this effect was not significant in virgin mice. In virgin mice, we observed post-menopausal switch of tumor-free survival. The pre-menopausal protection from mammary tumors could be due to presence of Estrogen (ER). Irrespective of parity, we observed significant reduction of mammary intraepithelial neoplasias (MINs or precancerous lesions) in PRAS40-/- versus PRAS40+/+ mice. To investigate the mechanism of action of ER in HER-2 over-expressing mice we treated ER positive cells with Doxorubicin, ER or the combination in vitro. Modulation of cell proliferation and apoptosis was determined by PRAS40 transient knockdown (siPRAS40) versus non-targeting (NT) following treatment in ER positive ZR-751 cells. To interrogate the effect of Doxorubicin, ER, in vitro, cell lines were treated with 6-24 hr Doxorubicin, ER or both. Doxorubicin, ER or combination treatment led to significant reduction in proliferation and increased apoptosis in siPRAS40 versus non-targeting (NT) ZR-751 cells. Together, our data suggests that ER may have an effect upon PRAS40 knockdown in vitro and in vivo. Our results show that PRAS40 could be a novel ‘druggable’ target for treating aggressive HER-2 positive breast cancers.

Citation Format: Ritu Malla, Jesika S. Faridi. PRAS40 (AKT1S1) ablation modulates breast cancer by increasing tumor-free survival in HER-2/neu overexpressing mice [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 LB-A21.
Abstract LB-A35: Discovery of a new kinase inhibitor targeting BRAF monomers and dimers
Authors: Cotto Rios Xiomaris M. , Agianian Paul , Wu Yang , Gavathiotis Evripidis
Published: August 2018

Increased activation of the RAS/RAF/MEK/ERK signaling pathway, through mutations in upstream activators or in components of the pathway, can lead to uncontrolled cellular growth and proliferation leading to tumor development. BRAF mutations are present in more than 50% of melanoma patients as well as in colorectal (5-10%), thyroid carcinomas (25-45%), hairy-cell leukemia (~100%) and less commonly in ovarian and lung malignancies. Specifically, activating BRAF mutation V600E in the kinase domain of BRAF accounts for almost 50% of melanoma. Although, FDA-approved RAF inhibitors vemurafenib and dabrafenib have elicited remarkable responses and improved survival of melanoma patients with BRAFV600E/K mutations, acquired resistance limits their effectiveness as patients relapse. Several studies have demonstrated that resistance in melanoma and other tumors involve increased formation of RAF dimers that are not effectively inhibited by clinical inhibitors. Hence, underscoring the need for improved RAF inhibitors. Toward this goal, we developed an in-cell-western assay to screen for small molecule kinase inhibitors of the ERK signaling pathway, using melanoma cells that express BRAFV600E monomers and dimers. Because several inhibitors have been identified to inhibit ERK signaling that led us to investigate the precise mechanism of inhibition. We performed structural characterization and biochemical analysis of the RAS/RAF/MEK/ERK signaling pathway in cells with different RAS/BRAF mutational background, expressing BRAF monomers and dimers. Our study enabled us to identify a kinase inhibitor that potently inhibits BRAF monomers and dimers, with distinct structural properties compared to current RAF inhibitors. Further development of this new class of RAF kinase inhibitor may lead to more effective ERK signaling inhibition and improved treatments for BRAF-dependent tumors.

Citation Format: Xiomaris M. Cotto Rios, Paul Agianian, Yang Wu, Evripidis Gavathiotis. Discovery of a new kinase inhibitor targeting BRAF monomers and dimers [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 LB-A35.
Abstract LB-B20: High-affinity antisense oligonucleotides targeting Foxp3 inhibit immunosuppressive function of regulatory T cells and produce anti-tumor effects in syngeneic tumor models
Authors: Revenko Alexey S. , Sinclair Charles , Johnson Ben , Hettrick Lisa , Peter Alison , Staniszewska Anna , Hughes Adina , Sandin Linda , Taylor Molly , Klein Stephanie , Watt Andy , Monia Brett , Edbrooke Mark , MacLeod A. Robert
Published: August 2018

Regulatory T cells (Treg) contribute to the progression of cancer through suppression of specific anti-tumor effector immune responses. Therefore, inhibition of Treg function is an attractive approach for cancer immunotherapy. However, despite substantial effort, specific inhibition of Tregs remains a challenge. Foxp3 is a Treg-specific transcription factor required for their development and function. We employed next-generation antisense inhibitors (Gen 2.5 cEt-modified ASOs) to selectively inhibit Foxp3 expression in mouse Treg cells and evaluated consequences of ASO-mediated Foxp3 knock-down in vitro and in vivo. Mouse Foxp3-specific ASOs produced potent dose-dependent reductions in Foxp3 mRNA and protein in mouse Tregs in vitro without the use of transfection reagents. Reductions of Foxp3 in mouse Tregs was associated with loss of expression of immunosuppressive markers as well as loss of immunosuppressive function in vitro. Systemically delivered unformulated cEt-modified mouse Foxp3 ASOs reduced Foxp3 mRNA and protein in Tregs in normal mice. Importantly, this inhibition, in contrast to the phenotype of Foxp3 KO mice, was not associated with a significant autoimmune phenotype. When mouse Foxp3 ASOs were administered to syngeneic tumor-bearing mice they produced significant Foxp3 mRNA and protein knockdown in tumor-infiltrating Tregs. The growth of tumors in mouse Foxp3 ASO-treated animals was significantly attenuated with a fraction of animals (25%-50%) achieving complete regressions. Anti-tumor activity of mouse Foxp3 ASOs was associated with immunophenotype changes consistent with the increased anti-tumor immune response. Overall these data demonstrate that regulatory T cells can be effectively targeted by ASOs and that Foxp3 ASOs represent a potentially attractive therapeutic approach in cancer immunotherapy.

Citation Format: Alexey S. Revenko, Charles Sinclair, Ben Johnson, Lisa Hettrick, Alison Peter, Anna Staniszewska, Adina Hughes, Linda Sandin, Molly Taylor, Stephanie Klein, Andy Watt, Brett Monia, Mark Edbrooke, A. Robert MacLeod. High-affinity antisense oligonucleotides targeting Foxp3 inhibit immunosuppressive function of regulatory T cells and produce anti-tumor effects in syngeneic tumor 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 LB-B20.
Abstract LB-B22: TNBC kinase prioritization for targeted therapy after chemotherapy resistance
Authors: Lim Bora , Park In Ah , Wang Ying , Bollu Lakshmi , Brown Powel , Baggerly Keith , Meric-Bernstam Funda , Ueno Naoto
Published: August 2018

Introduction: Triple negative breast cancer accounts for 10-15% of all breast cancers yet contribute to high recurrence and metastasis that leads to the death of patients. Lack of molecular therapeutic target for TNBC leaves the chemotherapy as only available options while many develop resistance to chemotherapeutics, leaving patients with TNBC at risk of accumulative toxicities and death. Thus, it is critical to identify unique molecular kinases that contribute to chemotherapy resistance. We hypothesize that differential level of kinase expression stratified based on the chemotherapy response, to discover putative targets. Methods and Material: We performed an in silico search of kinases using mRNA microarray data that are expressed with higher proportion in TNBC patient samples based on the chemotherapeutic response, to identify kinases that contribute to the resistance to neoadjuvant chemotherapy using mRNA sequencing data of 132 patients with TNBC. We then prioritize the putative resistance related kinases, based on priority scoring system we have developed, to select the top candidate kinase for further therapeutics development. Result: Eleven kinases were differentially expressed between the pCR and non-pCR patients samples at baseline, and prioritized based on our scoring system. MELK was selected as a top target kinase given the highest score and biological validation, and currently available inhibitor. Pre-clinical studies of MELK has shown efficacy in vitro and in vivo models. Conclusion: First in human trial of oral MELK inhibitor is currently launched to be tested in actual clinical setting in patients with TNBC, that will offer the opportunity for us to validate our prioritization scoring system and pre-clinical validation. Further clinical validation, which is ongoing, will support our in silico screening followed by a prioritization to select kinase inhibitor development in chemotherapy resistant TNBC.

Citation Format: Bora Lim, In Ah Park, Ying Wang, Lakshmi Bollu, Powel Brown, Keith Baggerly, Funda Meric-Bernstam, Naoto Ueno. TNBC kinase prioritization for targeted therapy after chemotherapy resistance [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 LB-B22.
Abstract LB-B32: Modulation of the Hedgehog signaling pathway in models of basal cell carcinoma by ATP-competitive PKCi inhibitors
Authors: Roffey Jon , Dillon Christian , Oro Anthony E. , Mirza Amar N. , Sarin Kavita Y. , Aasi Sumaira Z. , Parker Peter J. , Riou Philippe , Barton Caroline , Patel Bhavisha , Barton Caroline , Turnbull Andrew , Stanway Emma , Fowler Katherine , Ott Gregory , Ator Mark
Published: August 2018

We will describe for the first time the optimization and pharmacological characterisation of azaquinazoline based ATP-competitive inhibitors of the aPKC isoforms. The serine/threonine kinase protein kinase C iota (PKCι) and protein kinase C zeta (PKCζ) together define the atypical sub-class of the protein kinase C superfamily (aPKC). Both isoforms have emerged as master regulators of cellular polarity with PKCι implicated in the maintenance of aberrant Hedgehog (HH) pathway activity in basal cell carcinoma (BCC). Common activating mutations in the HH signalling pathway drive BCC growth through the transcription factor GLI. Inhibitors of membrane protein smoothened (SMO) are clinically effective suppressors of HH signalling in BCC. However, acquired and de novo resistance to SMO inhibitors poses severe limitations to the clinical use of these agents. PKCι has been shown to directly activate GLI1 in BCC and has been linked to SMO inhibitor resistance making a strong case for the development of a selective PKCι inhibitor. Insights from structural biology identified critical amino acid residues in the PKCι binding pocket that could be exploited through structure-based drug design to optimise inhibitor potency and selectivity over structurally related kinase targets. The phosphorylation status of the known PKCι proximal substrate LLGL2 was used as a cellular pharmacodynamic biomarker and to demonstrate in vivo PKCι inhibition. To investigate the effects of PKCι inhibitors on the HH pathway a panel of compounds covering a diversity of chemotypes were profiled using a Hedgehog pathway GLI1 reporter assay in an engineered NIH3T3 cell line. Murine and human BCC cells, dependent on HH signalling for survival, were sensitive to PKCι inhibitor treatment with concomitant dose and time dependent effects on the expression of the HH pathway activity biomarker GLI1. Taken together, these results have therapeutic implications making a strong case for further evaluation of PKCι inhibitors in the setting of SMO-inhibitor-resistant BCC cancers.

Citation Format: Jon Roffey, Christian Dillon, Anthony E. Oro, Amar N. Mirza, Kavita Y. Sarin, Sumaira Z. Aasi, Peter J. Parker, Philippe Riou, Caroline Barton, Bhavisha Patel, Caroline Barton, Andrew Turnbull, Emma Stanway, Katherine Fowler, Gregory Ott, Mark Ator. Modulation of the Hedgehog signaling pathway in models of basal cell carcinoma by ATP-competitive PKCi inhibitors [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 LB-B32.
Abstract 100: Interleukin 1 receptor type II upregulates MMP1 expression and increases motility of keratinocytes cells
Authors: Wang Hsiu-Hua , Lee Te-Chang
Published: August 2018

We have shown that long-term exposure to low doses of inorganic arsenite (iAs) induced malignant transformation of non-tumorigenic human keratinocytes, HaCaT cells. We further demonstrated that enhanced expression of a decoy type II receptor of interleukin-1 (IL1R2) in transformed keratinocytes mediated through IL-6 and VEGFR to increase the migration and invasion activities, indicating the oncogenic potential of IL1R2. In this present study, we further explored how IL1R2 enhances the cell motility in human keratinocytes. As described earlier, long-term and low dose iAs (0, 0.5 and 1 μM) exposed HaCaT cells were designated as HaCaT A0, A1 and A2 cells, respectively. The tumorigenic cell line, T4R2, was derived from the tumor in mice implanted with HaCaT A2 cells. By growing HaCaT A0, A1, A2 and T4R2 cells on an organotypic culture system using basal medium, we found that T4R2 cells formed multilayered morphology. By aid of siRNA and ectopic expression techniques, we further demonstrated that increased expression of IL1R2 in T4R2 cells was associated with increased matrix metalloproteinase-1 (MMP1) and enhanced cell motility. The roles of MMP1 on supporting the organotypic growth of T4R2 cells were confirmed by using the stably MMP1-silenced T4R2 cells (T4R2-shMMP1). The cell motility of T4R2-shMMP1 cells was also significantly reduced. Furthermore, IL1R2-induced MMP1 upregulation was remarkably inhibited by inhibitors of MAPK/ERK signaling. Our present results revealed that MMP1 was one of downstream targets of IL1R2 which plays a crucial role on the progression of malignancy. Therefore, IL1R2 may be a target for cancer intervention.

Citation Format: Hsiu-Hua Wang, Te-Chang Lee. Interleukin 1 receptor type II upregulates MMP1 expression and increases motility of keratinocytes cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 100.