bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2275: Intestine-specific homeobox (ISX) upregulates E2F1 expression and related oncogenic activities in HCC
Authors: Wang Shen-Nien , Wang Li-Ting , Hsu Shih-Hsien
Published: July 2016

Intestine-specific homeobox (ISX), a newly identified proto-oncogene, is known to regulate cell proliferation and drive hepatocellular carcinoma (HCC) formation; however, the underlying mechanisms linking gene expression and tumor formation remain obscure. In this study, we showed that ISX transcriptionally activates E2F1 expression and related oncogenic activity by directly binding to its promoter region. Mechanistically, forced ISX expression upregulated the expression and nucleus translocation of the E2F1-DP1 complex phosphorylated by the cyclin D1-CDKs complex, which promoted oncogenic activities of ISX-E2F1 axis in hepatoma cells. In addition, co-expression of both ISX and E2F1 significantly promoted cell proliferation and anti-apoptotic signals instead of apoptosis and autophagy induced by the tumor suppressors p53 and RB1. In contrast, short hairpin RNA-mediated attenuation of ISX and E2F1, respectively, in hepatoma cells decreased cell proliferation and malignant transformation in vitro and in vivo. The mRNA expression was compared in 238 paired specimens of HCC and adjacent normal tissues, and E2F1, as an expression of ISX, pathologically exhibited a tumor-specific expression pattern and was highly correlated with ISX expression, patient survival time, progression stage, and poor prognosis. Taken together, our results highlight that E2F1 is an important downstream gene of ISX in hepatoma progression.

Citation Format: Shen-Nien Wang, Li-Ting Wang, Shih-Hsien Hsu. Intestine-specific homeobox (ISX) upregulates E2F1 expression and related oncogenic activities in HCC. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2275.
Abstract 229: A metabolic switch controls cell fate decision-making in intestinal differentiation downstream of the tumor suppressor adenomatous polyposis coli (apc)
Authors: Sandoval Imelda T. , Delacruz Richard Glenn C. , Miller Braden N. , Satterfield Christeena , Olson Kristophor , Hill Shauna , Van Remmen Holly , Rutter Jared , Jones David A.
Published: July 2016

Mutation in the tumor suppressor Adenomatous Polyposis Coli (APC) is the primary initiating mutation in a majority of colon tumors. Recent studies have shown that APC positively correlates with Mitochondrial Pyruvate Carrier 1 (MPC1), a crucial player in pyruvate metabolism and has been reported to repress the Warburg effect and growth in colon cancer cells. Utilizing the zebrafish to examine the relationship between apc and mpc1, we found that mpc1 expression is reduced in embryos harboring a genetic mutation (apcmcr) or diminished expression (apc mo) of apc. Antisense morpholino knockdown of mpc1 in wild type embryos (mpc1 mo) resulted in an array of developmental defects that recapitulated phenotypes of impaired apc function including failed intestinal differentiation. This was accompanied by mitochondrial dysfunction in mpc1 mo as evidenced by a decrease in metabolic respiration and triglyceride levels. We also observed altered mitochondrial function and dysregulation of enzymes involved in pyruvate metabolism in apcmcr and apc mo. Moreover, hMPC1 RNA rescued intestinal differentiation in both zebrafish models of apc deficiency. Meta-analyses using TCGA human tumor samples corroborated our findings in the zebrafish. Our data demonstrate a novel role for apc in pyruvate metabolism through regulation of mpc1 that drives normal intestinal differentiation and support the broader idea that metabolic changes can dictate cell fate programs.

Citation Format: Imelda T. Sandoval, Richard Glenn C. Delacruz, Braden N. Miller, Christeena Satterfield, Kristophor Olson, Shauna Hill, Holly Van Remmen, Jared Rutter, David A. Jones. A metabolic switch controls cell fate decision-making in intestinal differentiation downstream of the tumor suppressor adenomatous polyposis coli (apc). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 229.
Abstract 2326: LTX-315, an oncolytic peptide, increases anticancer immunity mediated by CTLA4 blockade in an interleukin-2 receptor beta-chain-dependent manner
Authors: Yamazaki Takahiro , Vetizou Marie , Flores Camila , Marabelle Aurelien , Sveinbjørnsson Baldur , Rekdal Øystein , Kroemer Guido , Zitvogel Laurence
Published: July 2016

Intratumoral immunotherapies aim at reducing local immunosuppression as well as reinstating and enhancing systemic anticancer T cell functions without inducing side effects. LTX-315 is a first-in-class oncolytic peptide -based local immunotherapy that meets these criteria by inducing a type of malignant cell death that elicits anticancer immune responses. Here, we show that LTX-315 rapidly reprograms the tumour microenvironment by decreasing the local abundance of immunosuppressive Tregs and myeloid derived-suppressor cells and by increasing the frequency of polyfunctional TH1/TC1 cells with a concomitant raise in their expression of CTLA4 and a drop in PD-1 expression. Logically, in tumours that were resistant to intratumoural or systemic CTLA4 blockade, subsequent local inoculation of LTX-315 cured the animals or caused tumour regressions with abscopal effects(meaning that even malignant lesions that were established in the opposite flank and were not treated by LTX-315 responded to the therapy). This synergistic interaction between CTLA4 blockade and LTX-315 was reduced upon blockade of the β-chain of the interleukin-2 receptor (CD122) which is required for signalling in response to IL-2 and IL-15. This preclinical study provides a strong rationale for administering the oncolytic peptide LTX-315 to patients who are receiving treatment with the CTLA4 blocking antibody ipilimumab.

Citation Format: Takahiro Yamazaki, Marie Vetizou, Camila Flores, Aurelien Marabelle, Baldur Sveinbjørnsson, Øystein Rekdal, Guido Kroemer, Laurence Zitvogel. LTX-315, an oncolytic peptide, increases anticancer immunity mediated by CTLA4 blockade in an interleukin-2 receptor beta-chain-dependent manner. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2326.
Abstract 233: Identification of cancer vulnerabilities to metabolic perturbation using genome wide CRISPR screens
Authors: Chandrashekhar Megha , Arreger Michael , Seetharaman Ashwin , Hart Traver , Moffat Jason
Published: July 2016

The CRISPR-Cas9 system provides an effective way to introduce targeted loss-of-function mutations in mammalian cells. The advance that the CRISPR-Cas9 technology brings to human genetics sets the stage for identifying cellular fitness genes that operate either globally (core fitness genes) or specifically within a particular genetic background or environmental context (context-specific fitness genes). In tumors, this is the foundation for the concept of synthetic lethality as genes required in tumor cells but not in adjacent normal tissues should make ideal therapeutic targets with high effectiveness and minimal side effects. Towards this goal, we have developed a second-generation CRISPR gRNA library of 176,500 guides targeting 17,661 human protein-coding genes. We used the library to screen five human cell lines, representing a cross-section of wild type and cancer tissues, to identify genes whose knockouts induce significant fitness defects. Our screens accurately recapitulate pathway-specific genetic vulnerabilities induced by known oncogenes and identify novel context-specific vulnerabilities. Interestingly, we identified a specific dependency on mitochondrial activity and we validated this using various complex I inhibitors. This strongly supports the idea that oxidative phosphorylation (OXPHOS) dependency - a clear exception to the Warburg effect - is a targetable weakness of some tumors. In order to further understand this metabolic vulnerability, we performed a synthetic lethal screen to identify sensitizers of OXPHOS inhibition. Our screen revealed that inhibition of mitochondrial OXPHOS sensitizes the cells to loss of other metabolic pathways such as glycolysis, pentose phosphate pathway and lipid biosynthesis. Furthermore, loss of the cytosolic aspartate aminotransferase GOT1 was found to be synthetic lethal with perturbation of OXPHOS. This is consistent with the essential role of the electron transport chain in cell proliferation, which is to enable aspartate synthesis. Additionally, we also find novel genes, whose loss of function might alleviate the affect of OXPHOS perturbation. Our findings demonstrate that CRISPR-Cas9 screens enable a high-resolution view of the genetic vulnerabilities of a cell that may represent therapeutic opportunities in cancer. Further, synthetic lethal chemical-genetic screens can reveal novel functional drug combinations, which will enhance the efficacy of targeted therapies.

Citation Format: Megha Chandrashekhar, Michael Arreger, Ashwin Seetharaman, Traver Hart, Jason Moffat. Identification of cancer vulnerabilities to metabolic perturbation using genome wide CRISPR screens. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 233.
Abstract 2338: CD39+ Treg cooperate with a CD73-expressing Th1/Th17 subset for Adenosine-mediated immunosuppression in human breast tumors
Authors: Gourdin Nicolas , Rodriguez Céline , Vigano Selena , Durand Isabelle , Faget Julien , Jandus Camilla , Blay Jean Yves , Romero Pedro , Menetrier-Caux Christine , Caux Christophe
Published: July 2016

Our group and others have previously reported that Treg infiltrating (Ti-Treg) breast tumors have a negative impact on patients’ outcome. We further reported their selective recruitment in the tumor environment through CCL22 secretion and expansion upon ICOS engagement by plasmacytoïd dendritic cells.

Here, we investigated the mechanism of Ti-Treg mediated suppression and observed that Ti-Treg express high CD39 levels. CD39 is an ectonucleotidase that cooperates with CD73 to degrade the danger signal ATP into immunosuppressive Adenosine (Ado). The potency of Ado mediated suppression is illustrated in Adenosine-Deaminase (ADA)-deficient patients unable to degrade Ado and developing severe immunodeficiency.

We further show that, in contrast to murine Treg, human CD39+Treg do not express CD73 enabling them only to degrade ATP into AMP. Within T cells, CD73 expression was mainly associated with naïve CD8+ T cells and a subset of memory conventional CD4+ T cells (Tconv) that exhibit Th1/Th17 characteristics (CXCR3+CCR6+CCR4negIFNγhighIL17+). CD39+ Treg isolated from healthy donor blood, in presence of exogenous ATP, potently inhibit purified CD73+ but not CD73neg Tconv, proliferation and cytokine production (IFNγ, TNFα). By using enzymatic inhibitors, we demonstrated the involvement of CD39 and CD73 through Treg/Tconv cooperation for Ado mediated immunosuppression. Of importance, when integrated in [Treg-CD4+CD73+] high density coculture, CD4+CD73neg T cells expressing similar levels of Ado receptors (A2A, A2B) are also inhibited.

In conclusion, our findings support the existence of an Ado mediated immunosuppression loop in the tumor through cooperation between CD39highTreg and CD73-expressing Th1/Th17 subsets in the breast tumor environment.

The research leading to these results has received funding from the European Community's Seventh Framework Program (FP7/2007-2013) under grant agreement n°602200.

Citation Format: Nicolas Gourdin, Céline Rodriguez, Selena Vigano, Isabelle Durand, Julien Faget, Camilla Jandus, Jean Yves Blay, Pedro Romero, Christine Menetrier-Caux, Christophe Caux. CD39+ Treg cooperate with a CD73-expressing Th1/Th17 subset for Adenosine-mediated immunosuppression in human breast tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2338.
Abstract 234: Mitochondrial morphology as a biomarker of cancer phenotype and drug response
Authors: Giedt Randy J. , Fumene Fergulio Paolo , Pathania Divya , Yang Katherine S. , Kilcoyne Aoife , Vinegoni Claudio , Mitchison Tim J. , Weissleder Ralph
Published: July 2016

Mitochondria, critical organelles in quiescent and dividing cells, have been shown to vary in number, mass, and shape. While previous work has focused on understanding molecular mechanisms underlying changes in normal and immortalized cells, less is known about longer-term mitochondrial behavior such as morphological patterns in individual cells and overall populations, the heterogeneity and functional consequences of these patterns, and ultimately how potential mitochondrial heterogeneity can be exploited in the clinic. Indeed, while previous studies have been conducted illustrating mitochondrial dysfunction and morphological alterations in certain tumor types, more comprehensive analyses across tumor and cell types, as well as from cells derived from individual patients, have yet to be conducted. A primary impediment to this work is the technical challenge of consistently assaying mitochondrial morphology in diverse cell types where fixation procedures, collection techniques, and differing optical qualities between samples make potential analyses a challenging application.

We have developed an image based analytical technique to phenotype mitochondrial morphology in different cancers, including in vitro cancer cell lines and patient derived cancer cells. Our methodology is based on a combination of novel, clinically relevant collection and fixation techniques, and advanced image processing and computer learning analysis methodologies. Our results demonstrate that i) cancer cells of different origins, including patient-derived xenografts, express highly diverse mitochondrial phenotypes; ii) a given phenotype is characteristic of a cell population and fairly constant over time; iii) mitochondrial patterns correlate with cell metabolomics measurements and iv) therapeutic interventions can alter mitochondrial phenotypes in drug-sensitive cancers as measured in pre- versus post-treatment fine needle aspirates in mice. These observations shed light on the role of mitochondrial dynamics in the biology and drug response of cancer cells.

Citation Format: Randy J. Giedt, Paolo Fumene Fergulio, Divya Pathania, Katherine S. Yang, Aoife Kilcoyne, Claudio Vinegoni, Tim J. Mitchison, Ralph Weissleder. Mitochondrial morphology as a biomarker of cancer phenotype and drug response. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 234.
Abstract 2352: Vectorization in an oncolytic vaccinia virus of an antibody, a Fab and a scFv against programmed cell death -1 (PD-1) allow their intratumoral delivery and an improved tumor-growth inhibition
Authors: Marchand Jean-Baptiste , Kleinpeter Patricia , Fend Laetitia , Thioudellet Christine , Geist Michel , Sfrontato Nathalie , Koerper Véronique , Brandely Renée , Villeval Dominique , Rittner Karola , Silvestre Nathalie , Erbs Philippe , Zitvogel Laurence , Quemeneur Eric , Preville Xavier
Published: July 2016

We report here the successful vectorization of a hamster monoclonal IgG (namely J43) recognizing the murine Programmed cell death-1 (mPD-1) in Western Reserve (WR) oncolytic vaccinia virus. Three forms of mPD-1 binders have been inserted in the virus: whole antibody (mAb), Fragment antigen-binding (Fab) or single-chain variable fragment (scFv). MAb, Fab and scFv were produced and assembled with the expected patterns in supernatants of cells infected by the recombinant viruses. The 3 purified mPD-1 binders were able to block the binding of mPD-1 ligand to mPD-1 in vitro. Moreover, mAb was detected in tumor and in serum of C57BL/6 mice when the recombinant WR-mAb was injected intratumorally (IT) in B16F10 and MCA 205 tumors. The concentration of circulating mAb detected after IT injection was up to 1900-fold higher than the level obtained after a subcutaneous (SC) injection (i.e. without tumor) confirming the virus tropism for tumoral cells and/or that tumoral microenvironment allows virus escape from immune surveillance. Moreover, the overall tumoral accumulation of the mAb was higher and lasted longer after IT injection of WR-mPD-1, than after IT administration of 10 μg of J43. Interestingly, in the MCA 205 tumor model, WR-mPD-1 (both mAb and scFv) induced a therapeutic control of tumor growth similar to unarmed WR combined to systemically administered J43 and superior to that provided by an unarmed WR. These results pave the way for next generation of oncolytic vaccinia armed with immunomodulatory therapeutic proteins such as mAbs. New generation of oncolytic vaccinia virus that will express several transgenes simultaneously may also be designed with the goal of providing to the patients enhanced therapeutic/toxicity ratio.

Citation Format: Jean-Baptiste Marchand, Patricia Kleinpeter, Laetitia Fend, Christine Thioudellet, Michel Geist, Nathalie Sfrontato, Véronique Koerper, Renée Brandely, Dominique Villeval, Karola Rittner, Nathalie Silvestre, Philippe Erbs, Laurence Zitvogel, Eric Quemeneur, Xavier Preville. Vectorization in an oncolytic vaccinia virus of an antibody, a Fab and a scFv against programmed cell death -1 (PD-1) allow their intratumoral delivery and an improved tumor-growth inhibition. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2352.
Abstract 2391: Flow cytometric sorting of subpopulations followed by RNASeq reveals distinct phenotypes in PDX model of basal breast cancer
Authors: Porter Warren , Hahn Friedrich , Snowden Eileen , Ferguson Mitchell , Tong Frances , Dillmore Shannon , Parker Joel S. , Middlebrook Aaron , Ghanekar Smita , Blaesius Rainer
Published: July 2016

The recognition of tumor tissue as an interactive ecosystem of distinct cell types has recently emerged as a very promising basis for more successful treatment of cancer patients. While intratumor heterogeneity (ITH) as a phenomenon has been known for decades it is only recent that its functional significance can be investigated with effective tools. Starting with a correlation of cellular heterogeneity with aggressiveness, metastatic potential and drug susceptibility of a cancerous lesion the current focus on functional differences between various tumor cell compartments is revealing a number of distinct functions and interactions. The discovery of communication between various tumor cells through soluble factors as well as differences in implantation of homogeneous vs. heterogeneous cell populations into immune compromised mouse models suggest a “division of labor” among cell types within many tumor tissues.

We have investigated the surface marker distribution of more than 8 different PDX tumor models by flow cytometry and detected extensive immunophenotypic heterogeneity. Using a range of markers associated with cancer stem cells, EMT and invasiveness (e.g. CD 24, 44, 133, 184, 326 (EpCAM), and CD45) we find heterogeneity with respect to many surface markers as well as individual immunophenotypic signatures for each model. Building on this characterization we chose several markers for sorting of subpopulations and performed gene expression analysis. Transcriptome analysis of a breast cancer model revealed two phenotypic signatures which suggest a strong proliferative population alongside a second population which is far less proliferative but much more active in angiogenesis, ECM organization and secretion of various soluble factors. This observation suggests a very clear example of distinct roles of multiple cell types to form a tumor tissue.

Our findings could have implications for therapeutic strategies directed at more than one cell type as well as development of better diagnostic tools which take into account the presence of various phenotypically distinct cell populations.

Citation Format: Warren Porter, Friedrich Hahn, Eileen Snowden, Mitchell Ferguson, Frances Tong, Shannon Dillmore, Joel S. Parker, Aaron Middlebrook, Smita Ghanekar, Rainer Blaesius. Flow cytometric sorting of subpopulations followed by RNASeq reveals distinct phenotypes in PDX model of basal breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2391.
Abstract 2413: Cell type-specific deconvolution of heterogeneous tumor samples with immune infiltration using expression data
Authors: Wang Zeya , Morris Jeffrey S. , Holmes Chris C. , Ahn Jaeil , Li Bo , Lu Wei , Tang Ximing , Wistuba Ignacio I. , Wang Wenyi
Published: July 2016

Tumor tissue samples comprise a mixture of cancerous and surrounding stromal cells. Understanding tumor heterogeneity is crucial to analyzing gene signatures associated with cancer prognosis and treatment decisions. Compared with the experimental approach of using laser micro-dissection to isolate different tissue components, in silico dissection of mixed cell samples is faster and cheaper. Numerous computational approaches previously developed have limited ability to deconvolute heterogeneous tumor samples. We have developed a deconvolution model, DeMix-T, that can explicitly account for a third component such as infiltrating immune cells, and address this challenging problem when the observed signals are assumed to come from a mixture of three cell compartments, infiltrating immune cells, the tumor microenvironment and cancerous tissues. The optimization-based algorithm for DeMix-T finds a local optimum for our estimation problem and is computationally feasible when it needs to compute high-dimensional integrals. DeMix-T therefore involves a novel two-stage filtering method that yields accurate estimates of cell purities and compartment-specific expression profiles. Simulations and real data analyses have demonstrated the good performance of our method. Compared with other deconvolution tools, DeMix-T can be applied more widely and provides deeper insight for cancer biomarker studies. It allows for a further understanding of immune cell infiltration in cancer and assists in the development of novel prognostic markers and therapeutic strategies.

Citation Format: Zeya Wang, Jeffrey S. Morris, Chris C. Holmes, Jaeil Ahn, Bo Li, Wei Lu, Ximing Tang, Ignacio I. Wistuba, Wenyi Wang. Cell type-specific deconvolution of heterogeneous tumor samples with immune infiltration using expression data. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2413.
Abstract 243: Investigating microtubule growth dynamics in patient-derived metastatic prostate cancer cells
Authors: Matov Alexandre , de Rooij Johan , Gatlin Jay , Rohrberg Julia , Ahmad Nikta , Aggarwal Rahul , Simko Jeff , Goga Andrei , Ryan Charles , Wittmann Torsten
Published: July 2016

Advanced prostate cancer (PC) is treated primarily by means of chemotherapy with one of the clinically approved microtubule (MT)-targeting agents (MTAs): paclitaxel, docetaxel and cabazitaxel. The mechanism of action of the MTAs on the cellular level is to bind to MTs and inhibit MT-dependent intracellular pathways, ultimately leading to cell death. In PC, MTAs are the only chemotherapy class shown to improve survival, however, there is high variability of response to MTA chemotherapy among patients as well as emergence of resistance to drug action which hampers the clinical efficacy. Clinicians need additional information to match individual patient tumors to the most effective drugs or refrain from treating patients that will not respond. However, the precise mechanism of action or resistance development to MTAs is not understood, which represents a critical gap in our knowledge to select the best treatment. Our hypothesis is that there are inherent differences in tumor MT dynamics among individual patients which dictates their response to treatment with specific MTAs. To this end, we envision that a systematic characterization of PC MT dynamics and their response to MTAs will allow chemotherapy customization and prolong survival. Specifically, our approach consists of the analysis of metastatic castrate resistant PC (mCRPC) organoids (Gao D. et al, 2014) derived from bone (acetabulum, vertebrae), soft tissue (salvage prostatectomy, lymph nodes), pleural effusion and circulating tumor cells biopsy samples obtained from metastatic patients who have received hormonal therapy and the MTA docetaxel or hormonal therapy alone or no treatment. We apply a quantitative single-cell image analysis algorithm (ClusterTrack) to measure a panel of twelve distinct MT dynamics parameters (a MT dynamics signature). Preliminary analysis suggests differences between different mCRPC organoids. MT tracking results indicate a correlation of decreased MT growth rate with increased Op18/stathmin expression. In this context, we hypothesize that differential expression of MT regulating genes affects specific parameters of MT dynamics, thus determining the sensitivity to MTA treatment.

Citation Format: Alexandre Matov, Johan de Rooij, Jay Gatlin, Julia Rohrberg, Nikta Ahmad, Rahul Aggarwal, Jeff Simko, Andrei Goga, Charles Ryan, Torsten Wittmann. Investigating microtubule growth dynamics in patient-derived metastatic prostate cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 243.
Abstract 2447: PIN1 protects GLI1 from ubiquitination and promotes Hedgehog-driven medulloblastoma tumorigenesis
Authors: Rual Jean-Francois M. , Xu Tao , Zhang Honglai , Park Sung-Soo , Venneti Sriram , Kuick Rork , Ha Kimberly , Michael Lowell , Santi Mariarita , Uchida Chiyoko , Uchida Takafumi , Srinivasan Ashok , Dlugosz Andrzej , Camelo-Piragua Sandra
Published: July 2016

Medulloblastoma is the most common malignant brain tumor of childhood. Therapeutic approaches to medulloblastoma have led to significant improvements, but are achieved at a high cost to quality of life. Aberrant upregulation of the hedgehog (Hh) pathway drives cerebellar tumorigenesis in ∼30% of medulloblastoma patients. Hh pathway inhibitors such as the SMO antagonist Vismodegib are currently being tested in Hh-activated medulloblastoma and the preliminary results are encouraging. However, resistance to SMO inhibition can be acquired, leading to relapse. Alternative therapeutic approaches are needed. We aim to uncover novel Hh signal modulators that are essential in medulloblastoma to maintain tumorigenic potential. Using our proteomic platform for systematic protein interaction mapping, we discovered a novel interaction between GLI1, a key transcription factor for the mediation of Hh signals, and PIN1, a peptidylprolyl cis/trans isomerase that regulates the post-phosphorylation conformation of its substrates. Our results support a molecular model in which PIN1 protects GLI1 from proteasomal degradation, thus contributing to the positive regulation of Hh signals. Most importantly, our in vivo functional analyses of PIN1 in mouse models of Hh-driven medulloblastoma demonstrate that the loss-of-PIN1 impairs tumor development and increases survival by 3 fold, from 57 to 158 days (P < 0.0001), establishing PIN1 as a key factor in Hh-driven medulloblastoma tumorigenesis. Finally, in human medulloblastoma tumor samples, the GLI1 and PIN1 proteins are correlated in their expression, supporting the relevance of the GLI1/PIN1 interaction in this disease context. In summary, the discovery of the GLI1/PIN1 interaction uncovers PIN1 as a novel therapeutic target in medulloblastoma tumorigenesis. If our hypothesis is validated, i.e., PIN1 inhibitors can improve survival in mouse models of Hh-driven medulloblastoma, our project will strongly justify testing the clinical relevance of PIN1 blockade in medulloblastoma patients.

Citation Format: Jean-Francois M. Rual, Tao Xu, Honglai Zhang, Sung-Soo Park, Sriram Venneti, Rork Kuick, Kimberly Ha, Lowell Michael, Mariarita Santi, Chiyoko Uchida, Takafumi Uchida, Ashok Srinivasan, Andrzej Dlugosz, Sandra Camelo-Piragua. PIN1 protects GLI1 from ubiquitination and promotes Hedgehog-driven medulloblastoma tumorigenesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2447.
Abstract 2475: Bmi1 is a therapeutic target in recurrent medulloblastoma
Authors: Singh Sheila K. , Garg Neha , Manornajan Branavan , Bakhshinyan David , Venugopal Chitra , Hallett Robin , Wang Kevin Xin , Ramaswamy Vijay , Cho Yoon-Jae , Mitra Siddhartha , Kaplan David , Davis Thomas , Taylor Michael
Published: July 2016

We describe the epigenetic regulator Bmi1 as a novel therapeutic target for the treatment of recurrent human Group 3 medulloblastoma, a childhood brain tumor for which there is virtually no treatment option beyond palliation. Through comparative profiling of primary and recurrent medulloblastoma, we show that Bmi1 defines a treatment-refractory cell population that is uniquely targetable by a novel class of small molecule inhibitors. When administered to mice xenografted with patient tumors, we observed significant reduction in tumor burden and increased mouse survival, without neurotoxicity. As Group 3 medulloblastoma is often metastatic and uniformly fatal at recurrence, with no current or planned trials of targeted therapy, an efficacious targeted agent would be rapidly transitioned to clinical trials.

Current clinical trials for recurrent medulloblastoma patients who no longer respond to risk-adapted therapy are based on genomic profiles of primary, treatment-naïve tumors. These approaches will provide limited clinical benefit for patients since recurrent metastatic Group 3 medulloblastomas are highly genetically divergent from their primary tumor. Our experimental approach defines a tractable target, the epigenetic regulator Bmi1, which characterizes not only recurrent medulloblastoma, but many other metastatic and treatment-resistant cancers. As future clinical oncology trials will most likely begin with relapsed patients, therapeutic targets from comparative analyses in primary and matched-recurrent tumors offer the greatest clinical yield and may be readily translated to the patient bedside.

Citation Format: Sheila K. Singh, Neha Garg, Branavan Manornajan, David Bakhshinyan, Chitra Venugopal, Robin Hallett, Kevin Xin Wang, Vijay Ramaswamy, Yoon-Jae Cho, Siddhartha Mitra, David Kaplan, Thomas Davis, Michael Taylor. Bmi1 is a therapeutic target in recurrent medulloblastoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2475.
Abstract 2533: Interlukin-1 (IL-1) may induce prostate cancer (PCa) stem-like cells
Authors: Thomas Shayna , Merchant Sana , Meade Rachel , Nawas Afshan Fathima , Delk Nikki
Published: July 2016

Inflammation is implicated in prostate cancer initiation and progression. Our lab found that the inflammatory cytokine, interleukin-1 beta (IL-1β) concomitantly upregulates the pro-survival scaffold protein, Sequestome-1 (SQSTM1/p62) and represses androgen receptor accumulation in a relatively small cell subpopulation within various prostate cancer cell lines. Given that cancer stem cell subpopulations have been isolated from isogenic cell lines and given that prostate cancer stem cells are androgen receptor negative, we hypothesized that the IL-1β-responsive subpopulation might be stem-like cells. Cancer stem cells are significant in prostate cancer because they are resistant to chemo-radiation and androgen-targeted therapies and can contribute to the tumor cell pool through asymmetric division. Thus, we analyzed the mRNA and protein accumulation of several stem cell markers in various prostate cancer cells lines exposed to IL-1β. We also have experiments underway to analyze stem cell biology in order to determine the functional significance of the IL-1β-responsive subpopulation. Thus far, we have discovered that IL-1β can induce stem cell marker mRNA and protein accumulation, suggesting that IL-1β alters prostate cell fate and supports the notion that inflammation contributes to prostate cancer initiation and progression.

Citation Format: Shayna Thomas, Sana Merchant, Rachel Meade, Afshan Fathima Nawas, Nikki Delk. Interlukin-1 (IL-1) may induce prostate cancer (PCa) stem-like cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2533.
Abstract 254: Lung cancer cells growing under prolonged period of serum starvation display increased stemness
Authors: Venkatadri Rajkumar , Yakisich Juan Sebastian , Azad Neelam , Iyer. Anand Krishnan V.
Published: July 2016

Purpose: Resistance to anticancer drugs is a common cause of failure in chemotherapy. We recently found that adherent cells growing under prolonged periods (7-12 days) of serum starvation become highly resistant to conventional anticancer drugs such as Paclitaxel, Hydroxyurea and Colchicine but retain sensitivity to therapeutic levels of the cardiac glycoside Digitoxin.

Objectives: The main goal of this study is to characterize the biological properties of cells growing under prolonged periods of serum starvation (PPSS), and to elucidate the underlying mechanism of chemoresistance to Paclitaxel and sensitivity to Digitoxin with particular emphasis on Sox2 and the PI3K/AKT signaling pathway.

Experimental setup: Distribution of cell cycle was characterized by flow cytometry. Cell viability was assessed using the MTT assay. Western blotting was employed to evaluate the expression of several key protein markers of cancer stemness (Sox2, Wnt), multidrug resistance (MDR1, ABCG2), epithelial mesenchymal transition (Vimentin), and cell survival (Bcl-2, XIAP, PI3K/AKT).

Results: Cells grown under PPSS showed a higher proportion of cells in G1/S and G2 compared to cells growing under routine culture conditions (RCCs). Western blot analysis showed that these cells expressed higher levels of Sox2, MDR1, ABCG2, Bcl-2 compared to cells growing under RCCs. Pretreatment of cells for 3 h with Verapamil or Sorafenib (MDR1 and ABCG2 inhibitors, respectively) followed by co-incubation with Paclitaxel for 72 h did not overcome Paclitaxel resistance. Obatoclax (a Bcl-2 inhibitor), Wortmannin or LY294002 (PI3K inhbitors) also failed to overcome Paclitaxel resistance. It was interesting to observe that cells growing under PPSS were highly resistant to Obatoclax, Wortmannin and LY294002 compared to cells growing under RCCs. However, these cells were highly sensitive to treatment with Digitoxin.

Conclusions: It is likely that multiple mechanisms (increased stemness, overexpression of multidrug resistance protein and prosurvival proteins) contributes to the resistance of cells under PPSS to Paclitaxel, Obatoclax and PI3K inhibitors. Preliminary results indicates that Digitoxin exerts its antiproliferative effect in part by downregulating Sox2. However, the lack of effect of Wortmannin and LY294002 on Paclitaxel resistance suggests that this effect is not via the PI3K/AKT pathway. Adherent cells growing under PPSS provide a simple yet powerful system to screen for drugs targeting cancer stemness.

Citation Format: Rajkumar Venkatadri, Juan Sebastian Yakisich, Neelam Azad, Anand Krishnan V. Iyer. Lung cancer cells growing under prolonged period of serum starvation display increased stemness. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 254.
Abstract 2560: Significant association between a fatty acid-related genetic variant and the risk of lung cancer
Authors: Wang Cheng , Qin Na , Zhu Meng , Hu Zhibin , Shen Hongbing
Published: July 2016

Systematically study the metabolism can help us understand the etiology of diseases. Recent metabolism GWAS provided us a chance to explore the association between serum metabolites and risk of diseases through genetic instruments. Based on the idea of mendelian randomization, we studied the associations between metabolites-related SNPs and lung cancer risk in 13,945 cases and 12,939 controls. We identified a fatty acid (FA) related SNP that was significantly associated with lung cancer risk (odd ratio (OR) = 0.87, P = 1.76×10-15) and this effect was stronger in females. We further validated a significant association between this SNP and serum levels of this FA (Beta = -0.57, P = 1.68×10-3) in 253 Chinese healthy individuals by LC-MS system. The association between the SNP and the expression of FA-related gene was also observed in the liver tissues (Beta = -0.84, P = 6.49×10-3). Together, we organized a mendelian randomization study which provided a FA related SNP as a female concentrated and smoke independent genetic determinant of lung cancer from the aspect of metabolites and proposed that higher level of this FA was a causal risk factor of lung cancer.

Citation Format: Cheng Wang, Na Qin, Meng Zhu, Zhibin Hu, Hongbing Shen. Significant association between a fatty acid-related genetic variant and the risk of lung cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2560.
Abstract 2567: Characterizing histologic subtypes in lung cancer using principal component analysis
Authors: Byun Jinyoung , Han Younghun , Amos Christopher I.
Published: July 2016

Lung cancer is the leading cause of cancer death in the United States and worldwide. The two major forms of lung cancer are small-cell lung carcinoma (SCLC) and non-SCLC (NSCLC). NSCLC is divided into three major histologic subtypes: Squamous-cell carcinoma, adenocarcinoma, and large-cell. Histological subtypes of cancers vary with respect to the genes that shows altered regulation, compared to normal bronchioepithelial cells. Lung cancer histologic diagnosis is clinically relevant because there are histology-specific treatment indications and contradictions.

Principal component analysis (PCA) is one of the useful statistical tools for analyzing multivariate data and recently high-dimensional data in genetics and genomics. We demonstrated the classification between two major subtypes of lung cancer: 488 squamous cell carcinoma and 788 adenocarcinoma cases. We selected the top 20k significant SNPs using logistic regression and then conducted PCA as the unsupervised approach.

We observed a distinct pattern between two major subtypes of NSCLC in genome-wide association study (GWAS). There were several publications to classify the subtypes of histology in lung cancer using gene expression data. This enables to understand the patterns for other subtypes of lung cancer in GWAS.

Citation Format: Jinyoung Byun, Younghun Han, Christopher I. Amos. Characterizing histologic subtypes in lung cancer using principal component analysis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2567.
Abstract 2574: Outcomes of contralateral prophylactic mastectomy in relation to familial history: a decision analysis
Authors: Davies Kalatu R. , Brewster Abenaa , Bedrosian Isabelle , Parker Patricia , Crosby Melissa A. , Peterson Susan K. , Shen Yu , Volk Robert , Cantor Scott B.
Published: July 2016

Purpose

Family history of breast cancer is associated with an increased risk of contralateral breast cancer (CBC) even in the absence of mutations in the breast cancer susceptibility genes BRCA1/2. We compared quality-adjusted survival outcomes after contralateral prophylactic mastectomy (CPM) with surveillance only (no CPM) among women with breast cancer in relation to degree of family history.

Methods

We created a microsimulation model for women with a first-degree, second-degree and no family history treated for a stage I, II, or III estrogen receptor (ER)-positive or -negative breast cancer at the ages of 40, 50, 60, and 70 years. The model incorporated a 10-year post-treatment period for risk of developing CBC and/or dying of the primary cancer or CBC. For each patient profile, we used 100,000 microsimulation trials to estimate the quality-adjusted life expectancy for two clinical strategies: CPM and no CPM.

Results

CPM had a minimal improvement on quality-adjusted life expectancy among women age 50 to 60 with no or a unilateral first or second-degree family history (range -.06 to 0.31) and was unfavorable for the majority of women age 70 with stage III breast cancer regardless of degree of family history (range -.08 to -.02). Sensitivity analysis showed the highest predicted benefit of CPM with 95% risk reduction was 0.57 QALY for a 40-year-old woman with stage I breast cancer who had a first-degree relative with bilateral breast cancer.

Conclusion

Women age 40 years with stage I breast cancer and a first-degree relative with bilateral breast cancer have a QALY benefit from CPM similar to that reported for BRCA1/2 mutation carriers. For the majority of women, having a family history does not improve the minimal effect of CPM on quality-adjusted life expectancy.

Citation Format: Kalatu R. Davies, Abenaa Brewster, Isabelle Bedrosian, Patricia Parker, Melissa A. Crosby, Susan K. Peterson, Yu Shen, Robert Volk, Scott B. Cantor. Outcomes of contralateral prophylactic mastectomy in relation to familial history: a decision analysis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2574.
Abstract 2618: Oncogenic mutant KRAS modulates CREB activation through MEK-ERK and AKT signaling in pancreatic cancer
Authors: Castellanos Jason , Srinivasan Supriya , Honnenahally Kumar , Shi Chanjuan , VanSaun Michael , Robbins David , Merchant Nipun , Nagathihalli Nagaraj
Published: July 2016

Introduction: Cyclic AMP (cAMP) response element binding (CREB) overexpression in pancreatic ductal adenocarcinoma (PDAC) is associated with poor outcome, however, the mechanism(s) driving CREB overexpression in PDAC are not fully understood. We investigated the association of CREB activation with oncogenic KRAS, MEK-ERK and AKT signaling pathways.

Experimental procedure: Mouse lines derived from the Ptf1aCre/+; LSL-KrasG12D/+ (K518), Ptf1acre/+;LSL-KrasG12D/+;Tgfbr2flox/flox (PKT), LSL-KrasG12D/+;Pdx1Cre/+ (PanIN) and LSL-KrasG12D/+; Trp53R172H/+;Pdx1Cre/+ (PDA) mouse models of PDAC, human immortalized pancreatic ductal epithelial lines (HPDE6-E6E7 or H6c7, HPNE E6/E7 and HPNE E6/E7/KRAS) were immunoblotted for phospho-CREB (pCREB) and total CREB expression. KRAS mutant PDAC cell lines and CREB shRNA flank xenografts (PKT GEMM and nude mice) were treated with CREB (ICG-001), MEK (AZD6244) and AKT (MK-2206) inhibitors. The effects on downstream signaling targets were interrogated with cell cycle, apoptosis, survival and anchorage-independent growth analysis. Human CREB shRNA cells were treated with AZD6244 and MK-2206 to confirm the molecular mechanism of the CREB inhibition together with MEK and AKT.

Results: The expression of pCREB was higher in cells with KRAS mutation. MEK inhibition resulted in activation of AKT, while combined inhibition of CREB and MEK prevented AKT reactivation. Treatment with the combination of MEK and CREB inhibitors significantly decreased tumorigenic potential and increased cell apoptosis. Combined MEK, AKT and CREB inhibition synergistically enhanced these effects further, more so in KRAS mutant cell lines. To explore the relationship of CREB, MEK and AKT signaling in vivo, PKT mice were treated with their respective inhibitors individually and in combination. Either CREB/MEK or CREB/AKT two drug combinations significantly extended the median survival compared with individual agents. Lysates from MEK and AKT inhibited tumors showed decreased phosphorylation of CREB, confirming that CREB is activated through both, MEK and AKT signaling in vivo.

Conclusions: Our study demonstrates that oncogenic KRAS activation enhances the expression of CREB through MEK and AKT signaling. CREB inhibition results in increased sensitivity to MEK and AKT targeted therapy in KRAS mutant PDACs.

Citation Format: Jason Castellanos, Supriya Srinivasan, Kumar Honnenahally, Chanjuan Shi, Michael VanSaun, David Robbins, Nipun Merchant, Nagaraj Nagathihalli. Oncogenic mutant KRAS modulates CREB activation through MEK-ERK and AKT signaling in pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2618.