bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4296: Identification of cancer specific protein 80 (CSP-80), a novel 80 kDa MAP1a-like protein in ovarian carcinoma cells
Authors: Fadiel Ahmed , Nair Viswam S. , Aceto Peter , Naftolin Frederick
Published: August 2019

Background: Although interfering with the actions of microtubule-associated proteins (MAP’s) is successful against ovarian epithelial carcinoma (OVCA), knowledge of the MAP’s in OVCA cells is lacking. We sought to identify cancer-specific MAP’s in OVCA cells.Methods: Four human OVCA cell lines, primary OVCA tissue, ascitic cells and metastases from 9 patients and normal ovarian tissue from six women were compared to control human and rat brain tissue, uterine myomas (benign tumors) and rat and human non-neural organs. Modified Western blotting using panels of anti-microtubule-associated protein monoclonal antibodies were used. An in-vitro brain and OVCA mixing and recovery experiment was carried out to assess possible degradation of MAP1a by OVCA. A paclitaxel-driven tubulin assembly assay was performed to determine whether the OVCA protein has microtubule-associated protein properties. The transcriptome of CSP-80 was sequenced using primer extension sequencing.

Results: (1) In contradistinction to the 350 kDa MAP1a present in control brain extracts, only an 80 kDa molecule with MAP1a immune-reactivity was found in OVCA cell lines and tissues. No immune-reactivity was present in the negative controls. (2)Following the mixing experiments there was no increase of CSP-80; CSP-80 is not a degradation artifact of MAP1a. (3) The paclitaxel-driven tubulin assembly assay showed that CSP-80 bound to microtubules during tubulin polymerization. (4) No CSP-80 was identified in human or rat non-malignant tissues including normal human and rat brain or normal human ovary, placenta or uterine myomas, or normal rat liver, spleen or lung. (5) cDNA sequencing shows a 2603 bp fragment at a 5’ terminal of p80 to be homologous with the analogous segment of MAP1a. (6) Further testing showed that CSP-80 was present in other reproductive and non-reproductive carcinomas. Again, no 350 kDa MAP1a was present. Studies are underway to determine whether CSP-80 is a mutated protein or the product of post-transcriptional modification.

Conclusion: CSP-80 is a novel cancer-related protein that appears to be limited to an 80 kDa sequence of the MAP1a gene, or a post-transcriptionally modified product. Since CSP-80 exhibits tubulin-binding activity, this may explain the efficacy of taxane derivatives. CSP-80 may disclose some aspects of carcinogenesis, be a valuable marker of cancer and therapeutic efficacy, and offer new avenues for cancer treatment.

Citation Format: Ahmed Fadiel, Viswam S. Nair, Peter Aceto, Frederick Naftolin. Identification of cancer specific protein 80 (CSP-80), a novel 80 kDa MAP1a-like protein in ovarian carcinoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4296.
Abstract 4312: Multiplex parallel perturbation of Akt and MAPk signaling cascades
Authors: Wagner Andrew R. , Newby Megan , Oakleaf Kary
Published: August 2019

PI3K/Akt and MAPk signal transduction pathways are frequently dysregulated in human cancers. Previous work described the molecular basis of pro-survival signals mediated by Akt and MAPk. Mutation in and alteration of these pathways lead to tumorigenesis. However, signal propagation varies across cell type and precise signaling kinetics is less well characterized. The goal of this study is to profile the functional state of the PI3k/Akt and MAPk signaling circuits by coupling cell viability to antibody microarray and immunofluorescence. Simultaneous detection of Akt and MAPk signaling nodes can characterize signaling parameters that correlate to localization patterns across cell type and drug treatment conditions. To examine how signal propagation varied between cell lines, staurosporine was utilized to broadly inhibit protein kinase activity in a cervical cancer cell line, HeLa, and an osteosarcoma cell line, U2-OS, as model systems. To investigate signaling pathways, each cell line was treated and analyzed in parallel by forward phase phospho-specific antibody microarray panels and high content analysis of immunofluorescent staining. Staurosporine inhibited cell proliferation in a time and concentration dependent manner in both cell lines. U2-OS cells had a higher IC50 compared to HeLa cells indicating markedly different signaling parameters between the two models. Our observations suggest detecting cell type specific signaling kinetics can be used as a framework to predict cell sensitivity to specific inhibitors and be used to monitor drug resistance.

Note: This abstract was not presented at the meeting.

Citation Format: Andrew R. Wagner, Megan Newby, Kary Oakleaf. Multiplex parallel perturbation of Akt and MAPk signaling cascades [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4312.
Abstract 436: Prediction of aggressive disease in metastatic castration-resistant prostate cancer: The role of very small nuclear circulating tumor cells
Authors: Chen Pin-Jung , Jan Yu Jen , Teng Pai-Chi , Chen Jie-Fu , Cheng Shirley , Yao Nu , Reis-Sobreiro Mariana , Lozano Amber , Gomez Amy , Tseng Hsian-Rong , Freeman Michael , Posadas Edwin
Published: August 2019

Background: Circulating tumor cells (CTCs) have arisen as a contemporary noninvasive prognostic biomarker for prostate cancer (PC). Previously, a subgroup of PC CTCs, with particularly small nuclei (<8.54 μm), were found to be correlated with poor prognosis and the emergence of visceral metastases (VM). This subgroup was named very-small nuclear CTCs (vsnCTCs). We proposed vsnCTCs as a biomarker of aggressive disease in metastatic castration-resistant PC (mCRPC). Previous Studies also showed that the disruption of emerin, a linker of nucleoskeleton and cytoskeleton complex proteins, increases the cancer cells' capacity of migration and invasion. We hypothesize that emerin mislocalization is potentially associated with vsnCTC formation and may be a critical step for metastasis.

Methods: 35 blood samples were obtained from PC patients who failed first-line androgen deprivation therapy (ADT) and starting 2nd line treatment with abiraterone, enzalutamide, or taxane-based chemotherapy. Using our NanoVelcro CTC assay, we captured, subclassified, and enumerated the CTCs from patient samples with high-resolution imaging. Survival analyses were performed to exam the correlation between vsnCTC presence and patients’ prognosis. Concurrently, emerin staining was performed and the distribution and expression levels of emerin were analyzed in selected vsnCTC samples.

Results: The presence of one or more vsnCTCs strongly correlated with inferior overall survival (OS), progression free survival (PFS), and time to VM (TTVM). We also observed lower emerin content in vsnCTCs compared to WBC, and more prominent emerin mislocalization in vsnCTCs compared to CTCs with larger nuclei.

Conclusion: Our study strongly demonstrated the importance of morphologic characterization of CTCs and suggested that vsnCTC is a blood-borne biomarker for prediction of aggressive disease. Additionally, emerin mislocalization in vsnCTCs could be a potential biological pathway behind this morphologic phenomenon.

Citation Format: Pin-Jung Chen, Yu Jen Jan, Pai-Chi Teng, Jie-Fu Chen, Shirley Cheng, Nu Yao, Mariana Reis-Sobreiro, Amber Lozano, Amy Gomez, Hsian-Rong Tseng, Michael Freeman, Edwin Posadas. Prediction of aggressive disease in metastatic castration-resistant prostate cancer: The role of very small nuclear circulating tumor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 436.
Abstract 4365: Induction of distinct p53 mutation types differentially influences the control of cellular iron metabolism
Authors: Dandekar Eshan , Srinivasan Aishwarya , Clarke Stephen , Montgomery Mckale
Published: August 2019

The most commonly mutated gene in all human cancers is the tumor suppressor gene p53, but in addition to loss of tumor suppressor functions, mutations in p53 can also promote cancer progression by altering cellular iron acquisition and metabolism. The primary objective of this work was to determine how p53 mutation status influences the molecular control of iron homeostasis. Though hundreds of p53 mutations have been identified, the majority occur within the DNA binding domain and can be subdivided into two broad classes: contact (e.g., R273H) or conformational (e.g., R175H). By generating cell lines with inducible versions of some of the most common conformational and contact-type p53 mutations we have established that introduction of specific p53 mutation types alone is sufficient to disrupt cellular iron metabolism. We also demonstrate these effects are mediated at least in part due to differences in the responsiveness of Iron Regulatory Proteins (IRP) to cellular iron availability. IRP are considered the master regulators of intracellular iron homeostasis because they coordinate the expression of iron storage (ferritin) and iron uptake (transferrin receptor) genes. In response to changes in iron availability cells harboring either a wild-type p53 or contact (R273H) p53 mutation display canonical IRP-mediated responses, but neither IRP1 RNA binding activity nor IRP2 protein levels are affected by changes in iron status in cells harboring the conformational type mutant (R175H). Yet, both contact and conformational mutants exhibit robust changes in ferritin and transferrin receptor protein expression in response to iron loading and iron chelation, respectively. These findings suggest a novel, IRP-independent mode of iron regulation in cells expressing conformational type p53 mutants. Preliminary proteomics data suggests that lack of IRP responsiveness in cells expressing conformational p53 mutations may result from impaired iron-sulfur cluster biogenesis. These findings are currently being explored as a means of exploiting distinct p53 mutation types to more favorably induce iron-mediated cell death via the activation of ferroptosis. As p53 is mutated in nearly half of all human cancers, and iron is necessary for cancer cell growth and proliferation, the studies have implications for a wide range of clinically important cancers.

Citation Format: Eshan Dandekar, Aishwarya Srinivasan, Stephen Clarke, Mckale Montgomery. Induction of distinct p53 mutation types differentially influences the control of cellular iron metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4365.
Abstract 4368: Investigating the role of IDH in normal metabolic and cancer pathways
Authors: DiDuca Nicholas , Roberts Sarah H. , Sturtevant Shane , Tipping Marla
Published: August 2019

Isocitrate dehydrogenase (IDH) has gained much attention due its frequent mutation in acute myeloid leukemia (AML) and glioblastomas. This enzyme is responsible for converting isocitrate into α-ketoglutarate (α-KG); when this gene is mutated it further converts α-KG into another metabolite, D-2-HG, that competes with α-KG. Production of D-2-HG causes diversion to a new metabolic pathway, as well as inhibits the activity of other enzymes in the cell. We have created flies that express the IDH mutant protein to investigate the other metabolic changes. One of these changes results in an embryo lethality. Additional model systems investigating larval and adult brains have shown glial cell inhibition. We hypothesize that harboring the IDH mutation will have a negative impact on the stable development of progeny.

Note: This abstract was not presented at the meeting.

Citation Format: Nicholas DiDuca, Sarah H. Roberts, Shane Sturtevant, Marla Tipping. Investigating the role of IDH in normal metabolic and cancer pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4368.
Abstract 4381: Investigating the reversible MDH1 catalytic reaction in squamous non-small cell lung cancer
Authors: Weeks Joi L. , Wells Grace , Alexander Sati , Metallo Christian , Sohl Christal D.
Published: August 2019

Non-small-cell lung cancer (NSCLC) is a leading cause of death in men and women worldwide. NSCLC relies on glycolysis to support cell proliferation and to synthesize proteins, nucleic acids and lipids. Malate dehydrogenase (MDH) is an enzyme critical for replenishing intermediates in the tricarboxylic acid (TCA) cycle and for helping to drive glycolysis through its reversible coenzyme system NAD+/NADH by interconverting oxaloacetate and malate. The cytosolic form of MDH (MDH1) has been reported to be amplified in squamous cell NSCLC, which has high glycolytic activity. Elucidation of the role of MDH1 in altering cellular metabolism to drive tumorigenic progression has yet to be determined. Thus, our interest lies in identifying the chemical and cellular characteristics required to drive the reversible MDH1 catalytic reaction in squamous cell NSCLC. Previously, we have shown that metabolic dehydrogenases are regulated by microenvironmental changes in pH and oxidation levels, and we are currently extending this work to MDH1. We are also evaluating various cell lines to gain a better understanding of how the MDH1 reaction can be altered to decrease the tumorigenic capacity of squamous cell NSCLC. Experimental knowledge obtained has the potential to increase our understanding of the MDH1 reaction and educate the design of future anti-tumor therapeutics.

Citation Format: Joi L. Weeks, Grace Wells, Sati Alexander, Christian Metallo, Christal D. Sohl. Investigating the reversible MDH1 catalytic reaction in squamous non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4381.
Abstract 4387: hnRNP Q1 promotes cell proliferation and tumorigenesis by translationally up-regulating cell cycle-related genes through the EGF pathway
Authors: Hung Liang-Yi
Published: August 2019

Heterogeneous nuclear ribonucleoprotein (hnRNP) Q1, an RNA-binding protein, has been reported as overexpressing in cancer cells. However, the role of hnRNP Q1 in tumorigenesis remains unclear. By using RNA-immunoprecipitation (IP) assay following next-generation sequencing, a group of cell cycle-related genes targeted by hnRNP Q1 were identified, including Aurora-A kinase. Overexpressed hnNRP Q1 can up-regulate Aurora-A and many spindle assembly checkpoint (SAC) proteins, but not alter their mRNA levels, through enhancing translational efficiency by interacting with the mRNA 5’-UTR. Ribosomal S6-IP and ribosomal profiling assay further confirmed the translational regulation of these mRNAs by hnRNP Q1. Stimulation with epidermal growth factor (EGF) enhances both binding between hnRNP Q1 and these mRNAs as well as the efficacy of the hnRNP Q1-induced translation of these mRNAs. EGF/hnRNP Q1-induced translation is mediated by the mTOR and ERK pathways. In addition, hnRNP Q1 overexpression is positively correlated with the levels of Aurora-A and these SAC genes in human colorectal cancer tissues. Taken together, our data suggest that hnRNP Q1 plays an important role in translationally regulating the expression of Aurora-A and a group of cell cycle-related genes, which increases cell proliferation and contributes to tumorigenesis in colorectal cancer. It may thereby contribute to tumorigenesis by translationally up-regulating these genes in colorectal cancer.

Citation Format: Liang-Yi Hung. hnRNP Q1 promotes cell proliferation and tumorigenesis by translationally up-regulating cell cycle-related genes through the EGF pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4387.
Abstract 4389: Post-translational modifications of histone demethylase JMJD1A in prostate cancer cells
Authors: Xu Songhui , Fan Lingling , Cui Xiaolu , Zhang Fengbo , Hussain Arif , Fazli Ladan , Gleave Martin , Qi Jianfei
Published: August 2019

Castration-resistant prostate cancer (CRPC) is the major cause of death for prostate cancer (PCa) patients. Re-activation of androgen receptor (AR) activity during androgen-deprivation therapy is believed to underlie CRPC development. We have found that histone demethylase JMJD1A primarily regulates AR and c-Myc activity and thus plays a key role in promoting PCa cell proliferation or survival. Unfortunately, specific JMJD1A inhibitors are not yet available. Here, we identified several post-translational modifications of JMJD1A by performing the JMJD1A immunoprecipitation and mass spectrometry analysis. These modifications include the canonical ubiquitination that targets JMJD1A for proteasome-dependent degradation, non-canonical ubiquitination that enhances the recruitment of co-activators, as well as those that can regulate these ubiquitination events. We also found that these modifications could be manipulated by commercially available inhibitors, to reduce the JMJD1A protein level and prostate cancer cell growth. Thus, targeting the JMJD1A modifications may serve as an alternative means to inhibit JMJD1A activity for the anti-PCa therapy.

Note: This abstract was not presented at the meeting.

Citation Format: Songhui Xu, Lingling Fan, Xiaolu Cui, Fengbo Zhang, Arif Hussain, Ladan Fazli, Martin Gleave, Jianfei Qi. Post-translational modifications of histone demethylase JMJD1A in prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4389.
Abstract 4396: Gli, not Androgen Receptor, is the primary driver of prostate cell growth
Authors: Foo Jane , Li Na , Massah Shabnam , Nouri Mannan , Wang Mike , Buttyan Ralph
Published: August 2019

Introduction Hedgehog (Hh) signaling regulates the activity of Gli transcription factors. Gli controls genes needed for development, cell growth and cell motility. Canonical Hh signaling through Smoothened [Smo] suppresses the proteolysis of Gli2 and Gli3, maintaining them in high molecular weight active forms. Previously, we showed that active androgen receptors ([AR] liganded AR full length and AR-V7) recognize and binds Gli3 its Protein Processing Domain. This binding overrides the need for Smo action and provides a means for stabilization and activation of Gli3 in prostate cancer (PCa) cells without Hh. Studies on the effects of AR binding to Gli2 are more challenging because it is expressed at much lower levels than Gli3. Here, we report that AR also affects Gli2 protein stability and show that Gli2, like Gli3, is a driver of PCa cell growth that is overexpressed in castration resistant disease. Method Immunohistochemistry (IHC) using Gli2- and Gli3-specific antibodies was used to assess expression of Gli2 and Gli3 in human PCa tumor microarrays. Western blot were used to identify and quantify levels of active Gli2 and Gli3 in androgen-treated PCa cells (LNCaP, LNCaP-AI, LAPC4). Proximity ligation assays (PLA) was used to visualize in situ and quantify AR-Gli2 complexes in PCa cells. Gli2- and Gli3-specific siRNAs were used to knock down Gli expression in AR+ (LNCaP-AI, LAPC4, 22Rv1) and AR- (PC3) PCa, cells followed by the Gli reporter assay and the cell growth assay. Results IHC outcomes showed that nuclear Gli2 and Gli3 protein expression was significantly higher in castration resistant tumors compared to primary disease. Androgens increased expression of active Gli2 and Gli3 protein expression in PCa cells and stimulated Gli reporter activity. PLA showed the presence of intranuclear complexes of Gli2/Gli3-AR-Full-length in androgen-treated LNCaP and Gli2-AR-V7 complexes in CWR22rv1 cells. Knockdown of Gli2 or Gli3 present significant reduction in Gli transcriptional activity as well as inhibition on growth of both AR+ and AR- PCa cells that were tested. Conclusion AR activity affects Gli2 processing, as it does for Gli3. We can visualize and quantify AR-Gli2/Gli3 complexes in situ in PCa cells. Gli2 suppression, as well as Gli3 suppression, has a profound effect on PCa cell growth but combined suppression has the strongest effects in certain PCa cells. Finally, Gli2 and Gli3 protein expression is elevated in castration resistant disease.

Citation Format: Jane Foo, Na Li, Shabnam Massah, Mannan Nouri, Mike Wang, Ralph Buttyan. Gli, not Androgen Receptor, is the primary driver of prostate cell growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4396.
Abstract 4398: KDM3A and DCLK1 interactions promote stemness and tumorigenesis in PDAC
Authors: Ghosh Chandrayee , Palaniyandi Kankaraj , Paul Santanu , Dandawate Prasad , Rawal Sonia , Subramaniam Dharmalingam , Padhye Subhash , Gunewardena Sumedha , Thomas Sufi , O'Neil Maura , Jensen Roy , Welch Danny , Milisky Sally , Weir Scott , Iwakuma Tomoo , Anant Shrikant , Dhar Animesh
Published: August 2019

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

Citation Format: Chandrayee Ghosh, Kankaraj Palaniyandi, Santanu Paul, Prasad Dandawate, Sonia Rawal, Dharmalingam Subramaniam, Subhash Padhye, Sumedha Gunewardena, Sufi Thomas, Maura O'Neil, Roy Jensen, Danny Welch, Sally Milisky, Scott Weir, Tomoo Iwakuma, Shrikant Anant, Animesh Dhar. KDM3A and DCLK1 interactions promote stemness and tumorigenesis in PDAC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4398.
Abstract 44: Assessment of pancreatic cancer 3D organotypic cultures as models for functional preclinical analysis
Authors: Nelson Shannon R. , Roche Sandra , O'Neill Fiona , Larkin AnneMarie , Crown John , Walsh Naomi
Published: August 2019

Pancreatic ductal adenocarcinoma (PDAC) is the deadliest of all cancers, with a five-year survival rate of 8%. Decades of research has done little to improve patient outcomes. To identify key therapeutic strategies, appropriate research preclinical models are critical for testing the efficacy of drugs or downstream functional genomic analysis. Current methods of growing PDAC established cell lines in a 2D monolayer do not fully represent how the tumor cells grow in vivo as they fail to recapitulate the physiology of tumors in vivo due to different architecture, adherence structures and biochemical gradients. Patient-derived xenografts can retain the histological and genetic characteristics of their donor tumor and can remain stable across passages. Three-dimensional (3D) organoids grown ex vivo are tractable also retain the architecture, genotype and phenotype of a patients’ tumor.

However, a detailed comparative assessment of the utility of organoids, matched 2D cell lines and 3D cell organotypic models to assess the complex biology, interactions, response to therapeutic regimens has not been performed.

Using our unique protocol, we have established PDAC organoids and isogenetically matched 2D cell lines derived from PDAC PDX tumors. To establish if these matched 2D cell lines grown in 3D can recapitulate the organoid model, we cultured the matched cell lines in 3D organoid media in non-adherent, Matrigel containing cultures. The expression of PDAC histological markers between the original tumor, the PDX tumor, organoid and matched cell line in 3D and 2D has identified differential expression of tumor initiating cell (TIC) markers. RNA-seq transcriptomics of the 2D cell line models, matched recapitulated 3D organotypic models, organoids, PDX-tumor and patient tumor will reveal the application of these models for ex vivo downstream functional analysis.

Citation Format: Shannon R. Nelson, Sandra Roche, Fiona O'Neill, AnneMarie Larkin, John Crown, Naomi Walsh. Assessment of pancreatic cancer 3D organotypic cultures as models for functional preclinical analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 44.
Abstract 4413: CDK6 overexpression promotes resistance to CDK4/6 inhibitors in breast cancer
Authors: Li Qing , Razavi Pedram , Li Zhiqiang , Paula Arnaud F. Da Cruz , Brogi Edi , Scaltriti Maurizio , Reis-Filho Jorge S. , Chandarlapaty Sarat
Published: August 2019

CDK4/6 inhibitors (CDK4/6i) are highly active therapies in estrogen receptor-positive (ER+) breast cancer. Unfortunately, tumor relapse on these agents is frequently encountered in clinical practice with limited data on the biologic mechanisms that can mediate resistance. We utilized cell line models, patient derived xenografts and patient samples to interrogate mechanisms of resistance to CDK4/6 inhibitors. A survey of genomic alterations associated with limited benefit of CDK4/6iidentified several alterations involving the Hippo pathway which could potentially impact CDK6 kinase expression. Immunohistochemistry from these patients revealed increased YAP nuclear translocation and high levels of CDK6 protein specifically in the group of patients with short progression-free survival (PFS) on CDK4/6i. A PDX model of acquired resistance to CDK4/6i also showed that prolonged treatment with CDK4/6i led to a subset of tumors that developed resistance, all of which showed Hippo pathway suppression and CDK6 upregulation. Finally, cell lines models exposed to CDK4/6i showed multiple clones that featured upregulation of CDK6 through suppression of the Hippo pathway or amplification of the CDK6 gene. Identifying CDK6 overexpression as a recurrent feature of CDK4/6i resistant tumors, we next investigated the function(s) of CDK6 in our models. We performed knockdown of CDK6 by shRNA and found its overexpression to be necessary for drug resistance in these models while reinforced CDK6 could restore resistance or confer resistance when overexpressed in naïve cells. Given the close homology of CDK4 and CDK6, we asked whether any differences might exist between CDK4 and CDK6 complexes, performing immunoprecipitation and mass spectrometry (IP-MS) and found CDK6 to bind a distinct partition of proteins from CDK4 including INK4 proteins. In vitro kinase assays revealed that INK4 proteins impaired the ability of CDK4/6i to block CDK6 activity. INK4 proteins were found to cooperate with CDK6 in mediating drug resistance as their knockdown restored drug sensitivity to resistant cells, while INK4 overexpression promoted resistance in CDK6-high cells. Taken together, the data revealed that high levels of a CDK6-INK4 complex to be a recurrent mechanism of resistance to CDK4/6i and suggest novel CDK6 inhibitors as a strategy to overcome resistance.

Citation Format: Qing Li, Pedram Razavi, Zhiqiang Li, Arnaud F. Da Cruz Paula, Edi Brogi, Maurizio Scaltriti, Jorge S. Reis-Filho, Sarat Chandarlapaty. CDK6 overexpression promotes resistance to CDK4/6 inhibitors in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4413.
Abstract 4414: Inhibition of CDK2 overcomes primary and acquired resistance to CDK4/6 inhibitors
Authors: Hall Claire R. , Bisi John E. , Strum Jay C.
Published: August 2019

The cyclin dependent kinase (CDK) family of proteins is associated with cell cycle progression and transcriptional regulation. Abnormalities in the cell cycle, including modifications to the function of CDKs, their regulators (cyclins), or their natural inhibitors, are frequently associated with the formation and growth of tumors. While recent advances in treatments using CDK inhibition have focused on targeting CDK4/6, with regulatory approvals of palbociclib, ribociclib, and abemaciclib, these compounds only target tumors sensitive to CDK4/6 inhibitors. We are focused on developing a novel, potent, and selective inhibitor of CDK2 to treat patients whose tumors are insensitive to CDK4/6 inhibition, either by primary resistance or acquired resistance by prior treatment with a CDK4/6 inhibitor. CDK2, a serine-threonine kinase, is a member of the CDK family that binds two regulatory cyclins, E and A. CDK2 when complexed to cyclin E is involved in the G1 to S-phase transition. However, when CDK2 is complexed with cyclin A, the cell will progress through the S to M-phase. Overexpression of cyclin E has been described in a subset of triple negative breast cancer (TNBC), tumors with acquired resistance to CDK4/6 inhibition such as ER+ Her2- breast cancer, as well as ovarian, lung, and other tumor types. We have utilized medicinal chemistry and structure activity relationship (SAR) modeling, starting from our proprietary scaffold, to generate a series of small molecule CDK2 inhibitors with drug-like properties. These compounds were initially screened for potency and selectivity using an array of biochemical and in-vitro assays. We identified multiple small molecule inhibitors with sub-nanomolar biochemical IC50s for CDK2 when complexed with either cyclin E or cyclin A and evaluated their activity in normal cell lines, a breast cancer cell line resistant to CDK4/6 inhibition, TNBC, and other tumor cell lines. We examined cell cycle analysis, EdU incorporation, cell proliferation, caspase activation, and western blot analysis of genes associated with the downstream targets of CDK2. These CDK2 inhibitors potently arrest cells in the G2/M-phase and inhibit proliferation in a manner dependent on time and dose, with a corresponding decrease in phosphorylated Rb. Our lead compound was also evaluated in mouse xenograft studies for efficacy, investigating tumor growth inhibition in a model with cyclin E overexpression and a model with an acquired resistance to CDK4/6 inhibition. These potent CDK2 inhibitors demonstrate a potentially promising method of treating tumors with primary or acquired resistance to CDK4/6 inhibitors.

Citation Format: Claire R. Hall, John E. Bisi, Jay C. Strum. Inhibition of CDK2 overcomes primary and acquired resistance to CDK4/6 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4414.
Abstract 4420: Small-molecule inhibition of Wee1 kinase by AZD1775 selectively sensitizes human papilloma virus (HPV)-associated cervical cancer to DNA-damaging therapies
Authors: Kobayashi Osamu , Ikeda Yuji , Okuma Yuki , Hayashi Nobuki , Nakajima Takahiro , Asai-Sato Mikiko , Kawana Kei
Published: August 2019

Objective: Wee1 regulate G2-M checkpoint of cell-cycle Inhibition of Wee1 promotes cell mitosis without DNA repair in cases with TP53 deficiency Since human papillomavirus (HPV) E6 involves the inactivation of p53, we aimed to evaluate effects of Wee1 inhibitor on cervical cancer.

Material and Methods: Expression level of Wee1 in cervical cancer was evaluated using Oncomine Cervical cancer cell lines, Caski (HPV16+), SiHa (HPV16+) and C33A (HPV-, P53 mut) and LNCap (HPV-, P53 wt, prostate cancer) were used. After exposure to either Wee1 inhibitor (AZD1775), cisplatin, or both, cell surviving rate was evaluated by MTT assay and expression levels of Wee1 and cell cycle related proteins were evaluated by western blotting cell cycle status in cell lines were observed by flow cytometry.

Results: High expression of Wee1 in cervical cancer was clinically observed among ten cancer species. Stepwise treatment of AZD1775 promoted significant cell death induction, compared with exposure to cisplatin alone in HPV-positive cells (Caski and Siha); however no effect on cell death in HPV-negative cells (C33A and LNCap). In addition, expression level of pCDC2 was reduced after exposure to AZD1775, indicating induction of cell mitosis without DNA repair.

Conclusion: Our results indicate the therapeutic potential of cervical cancer treatment by Wee1 inhibition. Synergistic effect of Wee1 inhibition with conventional treatments (CCRT or chemotherapy) may be a new strategy to improve the prognosis in cervical cancer.

Citation Format: Osamu Kobayashi, Yuji Ikeda, Yuki Okuma, Nobuki Hayashi, Takahiro Nakajima, Mikiko Asai-Sato, Kei Kawana. Small-molecule inhibition of Wee1 kinase by AZD1775 selectively sensitizes human papilloma virus (HPV)-associated cervical cancer to DNA-damaging therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4420.
Abstract 4421: SY-5609, an orally available selective CDK7 inhibitor demonstrates broad anti-tumor activity in vivo
Authors: Hu Shanhu , Marineau Jason , Hamman Kristin , Bradley Michael , Savinainen Anneli , Alnemy Sydney , Rajagopal Nisha , Orlando David , Chuaqui Claudio , Olson Eric
Published: August 2019

Previously, we reported on a series of highly potent, selective, and non-covalent CDK7 inhibitors that demonstrated antiproliferative activity against triple-negative breast cancer (TNBC) and ovarian cancer (OVA) cell lines and tumor growth inhibition in cell line-derived (CDX) and patient-derived (PDX) mouse xenograft models. Here, we report on the in vitro and in vivo profile of our development candidate, SY-5609. Methods: Kinase inhibition assays at both Km and 2 mM [ATP] were used to assess inhibition of CDK2, CDK7, CDK9, and CDK12. SPR was used to determine the Kd, kon, and koff binding characteristics of SY-5609 to immobilized CDK7/Cyclin H dimer. CDK7 compound occupancy was determined using a biotinylated small molecule probe to pull down free CDK7 following incubating of HL60 cells with SY-5609. Inhibition of tumor cell line growth was assessed following 72 hrs of incubation with SY-5609. Flow cytometry was used to assess apoptosis and cell cycle modulation after 48 hrs of treatment. Effects on DNA damage and repair were assessed by immunofluorescence staining for γH2AX and RAD51 proteins. To assess in vivo effects, mice were implanted subcutaneously and randomized for treatment when tumors reached 150-200 mm3 and dosed orally for 3 weeks by both QD and BID dosing regimens. Collected tumor tissue samples were analyzed for protein levels of MCL1, pCDK2, MYC, and RNA Pol II CTD pSer5 by western blot. Results: SY-5609 bound CDK7/Cyclin H with a Kd of 0.059 nM and occupied CDK7 in HL60 cells with an EC50 of 33 nM. Cell growth inhibition EC50 values were 6-17 nM in a panel of solid tumor cell lines. Selectivity of SY-5609 over CDK12, CDK9, and CDK2 was 2492-, 2508-, and 8068-fold, respectively. SY-5609 led to induction of apoptosis, cell cycle arrest, and inhibition of DNA damage repair in tumor cell lines. Dose-dependent tumor growth inhibition was observed in a panel of CDX and PDX solid tumor models with both QD and BID dosing of SY-5609 with resulting decreases in direct (pCDK2, RNA Pol II CTD pSer5) and indirect (MCL1, MYC) protein biomarkers. In summary, we describe SY-5609, an orally available, potent, and selective CDK7 inhibitor that drives strong responses in CDX and PDX tumor models. These data support the rationale for advancing SY-5609 into IND-enabling studies.

Citation Format: Shanhu Hu, Jason Marineau, Kristin Hamman, Michael Bradley, Anneli Savinainen, Sydney Alnemy, Nisha Rajagopal, David Orlando, Claudio Chuaqui, Eric Olson. SY-5609, an orally available selective CDK7 inhibitor demonstrates broad anti-tumor activity in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4421.
Abstract 4422: Molecular and functional characterization of alpha satellite non-coding RNAs
Authors: Cáceres Rodrigo E. , Andonegui Marco A. , Oliva Diego A. , González Rodrigo , Luna Fernando , Arriaga Cristian G. , López Alejandro , Prada Diddier G. , Castro Clementina , Molina Paulina , Rosa Carlos De la , Reyes José L. , Hédouin Sabrine , Hubé Florent , Francastel Claire , Herrera Luis A.
Published: August 2019

Eukaryotic cell cycle progression requires the coordination of multiple molecular events in space and time to bring about proper transition from one phase to the next, and to ensure faithful genomic inheritance to daughter cells. The roles of coding transcription, translation, and RNA/protein degradation in cell cycle regulation are straightforward, since they control the abundance of proteins necessary for its progression. However, the contribution of non-coding transcription to this process is poorly understood. Non-coding transcription is notoriously interesting in mitosis for two reasons: First, transcription is repressed in most of the genome, but it is active in the centromere itself during mitosis; second, centromeric transcription produces non-coding RNA molecules which are integral components of the centromere and kinetochore and have functional roles in chromosome segregation. Here, we characterized the centromeric human alpha satellite non-coding RNAs (cencRNAs). We detected that the centromere produces high-molecular-weight (>5 kb) alpha satellite transcripts in sense and antisense orientation in several cancer cell lines and normal human leukocytes. These RNAs have a half-life of ~ 30 min and vary in abundance, but not in size, throughout the cell cycle. By analyzing their abundance under various conditions that promote mitotic arrest, we discovered a new association between proteasome inhibition and cencRNAs overexpression in G2/M HCT116 cells. We also show that their transcriptional inhibition mitigates the mitotic arrest induced by proteasome inhibitors. Furthermore, we demonstrate that exogenous expression of cencRNAs can slightly increase the mitotic index of SW480 cells. Using mass spectrometry-coupled RNA pulldown, we discovered that these RNAs interact with proteins essential for chromosome segregation. Our data show that centromeric transcription is regulated by proteasomes. Proteasomal inhibition promotes abnormal mitotic progression owing to the overexpression of non-coding RNAs at the onset of mitosis and the presumed impairment of their partner proteins functions in mitosis.

Citation Format: Rodrigo E. Cáceres, Marco A. Andonegui, Diego A. Oliva, Rodrigo González, Fernando Luna, Cristian G. Arriaga, Alejandro López, Diddier G. Prada, Clementina Castro, Paulina Molina, Carlos De la Rosa, José L. Reyes, Sabrine Hédouin, Florent Hubé, Claire Francastel, Luis A. Herrera. Molecular and functional characterization of alpha satellite non-coding RNAs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4422.
Abstract 4426: Selective inhibition of CDK9 induces apoptosis of TNBC cells independent of Rb status
Authors: Brighton Hailey E. , Hall Claire R. , Dillon Kerry A. , Bisi John E. , Strum Jay C.
Published: August 2019

The family of cyclin-dependent kinases (CDKs) are serine/threonine protein kinases important for cell cycle control and/or regulation of transcription. CDK9/CyclinT1 is a key regulator of transcription in eukaryotic cells and has been shown to be dysregulated at the level of protein and kinase activity in both hematologic and solid tumors. CDK9/CyclinT1 forms the active P-TEFb complex and phosphorylates Ser2 residues in the carboxy-terminal domain of RNA polymerase II (RNApol II) to initiate elongation of mRNA transcripts. CDK9 activity regulates transcription of a variety of short-lived transcripts that promote survival and directly suppress apoptosis in cancer cells, including MYC,XRN2, MCL-1,and XIAP. MYC-driven tumor types with Rb-loss or high expression levels of cyclin E, such as triple negative breast cancer (TNBC), are difficult to treat and are resistant to existing CDK4/6 inhibitors. Since CDK9 is upstream of these oncogenic drivers, inhibition of CDK9 could potentially bypass innate resistance mechanisms and induce cell death in TNBC through blocking expression of MYC and MCL-1, for example. To target CDK9 in TNBC, we used structure-based drug design and developed a library of novel, potent and selective CDK9 inhibitors (CDK9i). The lead CDK9i exhibit single digit nanomolar potency against CDK9/CyclinT1 complexes and good selectivity against other CDK family members in biochemical assays.

In addition, they also display high selectivity over 502 other kinases. Lead CDK9 inhibitors were found to potently inhibit phosphorylation of RNApol II Ser2 in a time and dose dependent manner in TNBC cells and decrease MYC, MCL-1 and XIAP at both mRNA and protein levels. Additionally, treatment of TNBC cells led to a potent G2/M cell cycle arrest, inhibition of cell proliferation and induction of apoptosis within 24 hours, regardless of Rb status of the tumor cells. Primary human bone marrow and normal human fibroblast cells, however, did not undergo apoptosis within 72 hours of treatment with CDK9i, suggesting a potential therapeutic window for CDK9i treatment. Further studies are ongoing to assess the effect of dose and scheduling on tumor efficacy in mouse TNBC tumor models. Selective inhibition of CDK9 presents a novel treatment strategy for difficult-to-treat tumor types, including those resistant to existing targeted therapeutics.

Citation Format: Hailey E. Brighton, Claire R. Hall, Kerry A. Dillon, John E. Bisi, Jay C. Strum. Selective inhibition of CDK9 induces apoptosis of TNBC cells independent of Rb status [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4426.
Abstract 4427: LS007, a potent and orally bioavailable CDK9 inhibitor, suppresses the growth of triple-negative and estrogen receptor-positive breast cancer
Authors: Rahaman Muhammed Hamidur , Zhang Yinghui , Islam Md Saiful , Heinemann Gary , Anshabo Abel Tesfaye , Albrecht Hugo , Milne Robert , Wang Shudong
Published: August 2019

Treatment of breast cancer represents a major therapeutic challenge, and thus identification of new targeted therapy is of paramount importance. Anti-apoptotic proteins, BCL2 and MCL1, and oncoprotein c-MYC are implicated in evasion of apoptosis and resistance to chemotherapy in both triple-negative breast cancer (TNBC) and estrogen receptor-positive breast cancer (ER+ BC). Transcription of these oncogenic factors requires cyclin dependent kinase 9 (CDK9). CDK9 phosphorylates the C-terminal domain (CTD) of RNA polymerase II (RNAPII) and acts as a rate-limiting step of transcription. Thus, targeting CDK9 can reduce the expression of these proteins effectively and simultaneously, presenting a promising therapeutic strategy for breast cancer. Utilizing extensive medicinal chemistry and biochemical assays, we previously identified and developed LS007 as an orally bioavailable (F = 56% in cynomolgus monkey at 4 mg/kg), and nanomolar inhibitor of CDK9 (Ki = 4 nM). In vitro, inhibition of CDK9-mediated phosphorylation of RNAPII (pRNAPIIS2) by LS007 resulted in downregulation of BCL2, MCL1 and c-MYC and activation of PARP cleavage indicating apoptosis in breast cancer cells (TNBC: MDA-MB-231, Hs578T and ER+ BC: MCF-7, T47D). In vivo, LS007 was well tolerated in mice after oral administration (MTD = 50 mg/kg QD and 100 mg/kg Q3D). In MDA-MB-231 TNBC xenograft, by daily oral dosing at 25 mg/kg and 50 mg/kg LS007 significantly reduced tumor growth (p < 0.001) with T/C of 53 % and 35 %, respectively, on day 21, when compared to the vehicle dosed group. Similarly, in MCF-7 ER+ BC xenograft model, oral dosing of LS007 at 25 mg/kg QD, 50 mg/kg Q2D and 75 mg/kg Q3D showed significant tumor growth inhibition with T/C of 50 %, 60 % and 47 %, respectively, and increased in animal survival (p < 0.001) compared to vehicle control. It was safe in the xenograft models as there was no significant body weight loss or other overt toxicities. In addition, histological analysis of major organs (liver, kidney, heart, bone marrow and intestine) of the mice receiving LS007 showed no drug related toxicities. These results support for development of LS007 towards the clinical trials for the treatment of TNBC and ER+ BC.

Citation Format: Muhammed Hamidur Rahaman, Yinghui Zhang, Md Saiful Islam, Gary Heinemann, Abel Tesfaye Anshabo, Hugo Albrecht, Robert Milne, Shudong Wang. LS007, a potent and orally bioavailable CDK9 inhibitor, suppresses the growth of triple-negative and estrogen receptor-positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4427.