bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 295: Efficacy of MCL1 inhibitor S63845 in small cell lung cancer
Authors: Yasuda Yuto , Ozasa Hiroaki , Tsuji Takahiro , Nomizo Takashi , Funazo Tomoko , Yoshida Hironori , Sakamori Yuichi , Hirai Toyohiro , Kim Young Hak
Published: August 2018

Lung cancer is the leading cause of cancer death. Small cell lung cancer (SCLC) is a histologic subtype of lung cancer and the proportion of SCLC is approximately 15%. New molecular targeted drugs and immune checkpoint inhibitors are successfully effective for non-small cell lung cancer. However, treatment of SCLC has not been improved over recent decades. It is important to explore new treatment strategies of SCLC. MCL1 is a member of the BCL-2 family, which regulates apoptosis. Targeting MCL1 represents a potential breakthrough of cancer treatment. We tested S63845, a MCL1 inhibitor, in four SCLC cell lines (DMS114, DMS53, SW1271, and NCI-H69) and, in addition, one patient derived SCLC cell (KTOR201). S63845 had greater efficacy in two of five SCLC cells (DMS114 and KTOR201). These two SCLC cells had higher expression of MCL1 and lower expression of BCL-XL, which is another member of the BCL-2 family. The other three SCLC cells (DMS53, SW1271 and NCI-H69) were resistant to S63845 and had a higher expression of BCL-XL or lower expression of MCL1. These data suggested that S63845 might be a powerful treatment of SCLC as a new therapeutic strategy. It is possible that the expressions of MCL1 and other members of the BCL-2 family predict the sensitivity of S63845.

Citation Format: Yuto Yasuda, Hiroaki Ozasa, Takahiro Tsuji, Takashi Nomizo, Tomoko Funazo, Hironori Yoshida, Yuichi Sakamori, Toyohiro Hirai, Young Hak Kim. Efficacy of MCL1 inhibitor S63845 in small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 295.
Abstract 2950: Development of a 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitor as a novel anticancer agent with minimal toxicity
Authors: Lee Ho-Jin , Min Hye-Young , Pham Phuong Chi , Baek Byungyeob , Kim Byungjin , Kim Yunha , Lee Jeeyeon , Lee Ho-Young
Published: August 2018

Both the type I insulin-like growth factor receptor (IGF1R) and Src pathways are associated with the development and progression of numerous types of human cancer, and Src activation confers resistance to anti-IGF1R therapies. Hence, targeting both IGF1R and Src concurrently is one of the main challenges in combating resistance to the currently available anti-IGF1R-based anticancer therapies. However, the enhanced toxicity from this combinatorial treatment could be one of the main hurdle for this strategy, suggesting the necessity of developing a novel strategy for co-targeting IGF1R and Src to meet an urgent clinical need. In the present study, We synthesized a series of 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitors, selected LL28 as an active compound, and evaluated its potential antitumor effects in vitro and in vivo. LL28 markedly suppressed the activation of IGF1R and Src and significantly inhibited the viability of several NSCLC cell lines in vitro by inducing apoptosis. Administration of mice with LL28 significantly suppressed the growth of H1299 NSCLC xenograft tumors without overt toxicity and substantially reduced the multiplicity, volume, and load of lung tumors in the KrasG12D/+-driven lung tumorigenesis model. These results suggest the potential of LL28 as a novel anticancer drug candidate targeting both IGF1R and Src, providing a new avenue to efficient anticancer therapies. Further investigation is warranted in advanced preclinical and clinical settings.

Citation Format: Ho-Jin Lee, Hye-Young Min, Phuong Chi Pham, Byungyeob Baek, Byungjin Kim, Yunha Kim, Jeeyeon Lee, Ho-Young Lee. Development of a 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitor as a novel anticancer agent with minimal toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2950.
Abstract 296: Loss of Romo1 enhances TRAIL-induced apoptosis through Bax upregulation in colon cancer
Authors: Jo Minjee , Kim Jung Lim , Jeong So Yeon , Kim Bo Ram , Na Yoo Jin , Park Seong Hye , Jeong Yoon A , Lee Dae-Hee , Oh Sang Cheul
Published: August 2018

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is a protein which is induces cell apoptosis in various cancer. To identify novel sensitizer of TRAIL, we knocked down Reactive Oxygen Species modulator 1 (Romo1). Romo1 is a mitochondrial membrane protein that is in charge of increasing ROS. Romo1 was highly upregulated in various cancers including colorectal cancer. Inhibition of Romo1 significantly increased TRAIL-induced apoptosis in colorectal cancer cells, not colon normal cells. Silencing of Romo1 has resulted in upregulation of Bax protein expression. It has been reported that Bax degraded by ubiquitination. We identify interaction between Bax and Parkin decreased in knockdown of Romo1 condition. Also, suppression of Romo1 lead to mitochondrial dysfunction. Our study suggests that inhibition of Romo1 enhanced TRAIL-mediated apoptosis by regulating Bax ubiquitination.

Citation Format: Minjee Jo, Jung Lim Kim, So Yeon Jeong, Bo Ram Kim, Yoo Jin Na, Seong Hye Park, Yoon A Jeong, Dae-Hee Lee, Sang Cheul Oh. Loss of Romo1 enhances TRAIL-induced apoptosis through Bax upregulation in colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 296.
Abstract 2986: E-cadherin/ROS1 inhibitor synthetic lethality in breast cancer
Authors: Bajrami Ilirjana , Marlow Rebecca , Ven Marieke van de , Brough Rachel , Pemberton Helen N. , Frankum Jessica , Song Fei Fei , Rafiq Rumana , Konde Asha , Menon Malini , Campbell James , Gulati Aditi , Kumar Rahul , Pettitt Stephen J. , Gurden Mark D. , Cardenosa Marta Llorca , Chong Irene , Gazinska Patrycja , Wallberg Fredrik , Sawyer Elinor J. , Martin Lesley-Ann , Dowsett Mitch , Linardopoulos Spiros , Ryan Colm , Derksen Patrick W. , Jonkers Jos , Tutt Andrew N.J. , Ashworth Alan , Lord Christopher J.
Published: August 2018

The E-cadherin (CDH1) tumour suppressor gene encodes a calcium-dependent cell-cell adhesion glycoprotein, which has roles in maintaining cell polarity, differentiation, cell migration and survival. E-cadherin dysfunction is a feature common to many epithelial tumours, with the highest incidence occurring in diffuse gastric cancer (50%) and lobular breast cancer (63%) and can occur via CDH1 mutation, deletion or epigenetic silencing. Although E-cadherin dysfunction is relatively common, precision medicine approaches that exploit this pathogenic alteration are not yet available. Using genetic and small-molecule perturbation screens in breast tumour cells with CRISPR-Cas9 engineered CDH1 mutations, we identified a synthetic lethal interaction between E-cadherin deficiency and inhibition of the tyrosine kinase ROS1. Using data from large-scale genetic screens in molecularly diverse breast tumour cell lines, we found that the E-cadherin/ROS1 synthetic lethality was not only robust in the face of considerable molecular heterogeneity but was also elicited with clinical ROS1 inhibitors including foretinib and crizotinib. ROS1 inhibitors induced mitotic abnormalities and multinucleation in E-cadherin defective cells, phenotypes that were associated with a defect in cytokinesis and aberrant p120-catenin phosphorylation and localisation. In vivo, ROS1 inhibitors produced profound anti-tumour effects in multiple, distinct, models of E-cadherin defective breast cancer. This data therefore provides the pre-clinical rationale for assessing ROS1 inhibitors such as the licensed drug crizotinib in appropriately stratified patients.

Citation Format: Ilirjana Bajrami, Rebecca Marlow, Marieke van de Ven, Rachel Brough, Helen N. Pemberton, Jessica Frankum, Fei Fei Song, Rumana Rafiq, Asha Konde, Malini Menon, James Campbell, Aditi Gulati, Rahul Kumar, Stephen J. Pettitt, Mark D. Gurden, Marta Llorca Cardenosa, Irene Chong, Patrycja Gazinska, Fredrik Wallberg, Elinor J. Sawyer, Lesley-Ann Martin, Mitch Dowsett, Spiros Linardopoulos, Colm Ryan, Patrick W. Derksen, Jos Jonkers, Andrew N.J. Tutt, Alan Ashworth, Christopher J. Lord. E-cadherin/ROS1 inhibitor synthetic lethality in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2986.
Abstract 2987: Identification of new combination therapies for lung tumors harboring KRAS mutations
Authors: Molina-Arcas Miriam , Moore Christopher , Rana Sareena , Maldegem Febe van , Horswell Stuart , Hancock David , Downward Julian
Published: August 2018

Oncogenic mutations in KRAS are frequent in non-small cell lung cancer (NSCLC) and have been associated with poor prognosis and resistance to existing therapies. Thus, new therapeutic strategies are needed to treat these tumors. We have previously shown that NSCLC cells harboring KRAS mutations are more sensitive to inhibition of KRAS downstream effectors MEK and RAF and to treatment with IGF1R inhibitors than their wild-type counterparts. In order to identify complementary targets for the improvement of IGF1R and/or MEK targeting therapies, we performed a whole-genome shRNA screen in KRAS-mutant NSCLC cells. Interestingly, the list of sensitizers to IGF1R inhibitors included several genes encoding components of the mTOR pathway. Viability assays in a panel of lung cancer cell lines confirmed that combinations of IGF1R inhibitors with mTOR inhibitors, both rapalogs and kinase inhibitors, resulted in a synergistic anti-proliferative effect in KRAS-mutant NSCLC cells. Mechanistic investigations demonstrated some differences between the effects of rapalogs and mTOR kinase inhibitors although, in both cases, mTOR inhibitors increased IGF1R and AKT phosphorylation. Combination with IGF1R inhibitors blocked the reactivation of the PI3K pathway resulting in a robust suppression of PI3K and mTORC1 signaling. Notably, the inhibition of these signaling pathways was stronger in KRAS-mutant cells than in wild-type cells. Addition of a MEK inhibitor to the combination produced a more profound and durable suppression of cell proliferation and a stronger induction of apoptosis. Finally, we validated the different drug combinations in mouse models of KRAS-induced NSCLC. Results showed that the three-drug combination produced a marked tumor regression in a NSCLC mouse model driven by mutant Kras and p53 loss-of-function and also in urethane-induced lung tumors. These findings suggest potential novel therapeutic strategies for NSCLC tumors harboring KRAS mutations.

Citation Format: Miriam Molina-Arcas, Christopher Moore, Sareena Rana, Febe van Maldegem, Stuart Horswell, David Hancock, Julian Downward. Identification of new combination therapies for lung tumors harboring KRAS mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2987.
Abstract 299: A susceptible-quiescent model can describe biphasic cell-kill by MCL1 inhibitor AZD5991 in vitro
Authors: Gibbons Francis D. , Belmonte Matthew , Secrist Paul , Schuller Alwin
Published: August 2018

AZD5991 is a potent and selective inhibitor of Mcl-1, now in phase 1 clinical development. Mcl-1 is an anti-apoptotic Bcl2-family protein that is up-regulated by cancer cells in order to avoid apoptosis. Disruption of binding of Mcl-1 to pro-apoptotic BH3-only proteins such as Bax and Bak results in loss in cellular viability of several cell-line models of multiple myeloma (MM). As a function of time, many cell lines display a biphasic response, with an initial period of rapid cell kill, followed by a period of slower kill. Such biphasic kill curves are not uncommonly seen in bacteria. As a function of concentration, cell lines display a range of efficacy (extent of cell kill) and potency (concentration of half-maximal cell kill). Here we apply a model originally developed for bacterial cell-kill to parameterize the in vitro cell kill over time and across several orders of magnitude in concentration. Cells from 10 MM cell lines were grown in culture, then plated at uniform density in microtiter plates where they were incubated at concentrations of AZD5991 ranging from 0.3nM to 30µM (with DMSO control), each plate for a duration of 0.5h to 72h. After the desired incubation period, Cell-Titer Glo® was used to assess cellular viability by luminescence. Plates were run in duplicate. A model of cell survival was implemented in MATLAB, in which cells can be in one of two states: a proliferating state ‘S' in which they are susceptible to a saturable concentration-dependent drug-induced cell death, or a quiescent state ‘Q' in which they don't proliferate and have only a constitutive death rate independent of drug concentration. Transition between the two states is possible in either direction. By fitting the model to the data across time and over a wide range of concentrations, we can succinctly and precisely describe the rate of growth and drug-induced cell death, as well as transition between the susceptible and quiescent states. To our knowledge, this represents the first application of such a model to a BH3 mimetic such as AZD5991. We find that the cell lines show much greater variation in efficacy (i.e., maximum inducible cell kill rate) than in potency, suggesting that the main difference between these lines lies in their dependence on Mcl-1 for survival.

Citation Format: Francis D. Gibbons, Matthew Belmonte, Paul Secrist, Alwin Schuller. A susceptible-quiescent model can describe biphasic cell-kill by MCL1 inhibitor AZD5991 in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 299.
Abstract 2990: Attenuation of RNA polymerase II pausing mitigates BRCA1-associated R-loop accumulation and tumorigenesis
Authors: Zhang Xiaowen , Chiang Huai-Chin , Wang Yao , Zhang Chi , Jin Victor X. , Hu Yanfen , Li Rong
Published: August 2018

Most BRCA1-associated breast tumours are basal-like yet originate from luminal progenitors. BRCA1 is best known for its functions in double-strand break repair and resolution of DNA replication stress. However, it is unclear whether loss of these ubiquitously important functions fully explains the cell lineage-specific tumorigenesis. In vitro studies implicate BRCA1 in elimination of R-loops, DNA-RNA hybrid structures involved in transcription and genetic instability. Here we show that R-loops accumulate preferentially in breast luminal epithelial cells, not in basal epithelial or stromal cells, of BRCA1 mutation carriers. Furthermore, R-loops are enriched at the 5′ end of those genes with promoter-proximal RNA polymerase II (Pol II) pausing. Genetic ablation of Cobra1, which encodes a Pol II-pausing and BRCA1-binding protein, ameliorates R-loop accumulation and reduces tumorigenesis in Brca1-knockout mouse mammary epithelium. Our studies show that Pol II pausing is an important contributor to BRCA1-associated R-loop accumulation and breast cancer development.

Citation Format: Xiaowen Zhang, Huai-Chin Chiang, Yao Wang, Chi Zhang, Victor X. Jin, Yanfen Hu, Rong Li. Attenuation of RNA polymerase II pausing mitigates BRCA1-associated R-loop accumulation and tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2990.
Abstract 2995: CDK9 phosphorylates BRG1 chromatin remodeler
Authors: Pandey Somnath , Zhang Hanghang , Barrero Carlos A. , Merali Salim , Graña Xavier , Issa Jean-Pierre
Published: August 2018

Cyclin-dependent kinase 9 (CDK9) belongs to the class of CDKs involved in transcription regulation along with CDK7, 8, 10-13. Earlier works have established that CDK9 is the catalytic subunit of P-TEFb, and a transcriptional activator. CDK9 inhibition holds promise for patients belonging to Chronic Lymphocytic Leukemia (CLL) and BRD4-NUT-rearranged NUT midline carcinoma (NMC) groups. It is therefore fundamentally important to understand CDK9 mediated gene regulation. CDK9 in complex with its regulatory subunit, Cyclin T1 or T2, is known to promote RNAPII promoter-proximal pause release by phosphorylating negative elongation factors. Additionally, phosphorylation of the C-terminal domain (CTD) of RNAPII on Serine-2 allows recruitment of RNA processing factors, which work on the nascent RNA as it emerges from RNAPII. It is however not known whether CDK9 has any transcriptional repression activity. Earlier work from our lab demonstrated that long-term CDK9 inhibition leads to the activation of BRG1, an ATP-dependent nucleosome-remodeling complex from the SWI/SNF family of proteins. We therefore hypothesized that CDK9 directly phosphorylates BRG1 and regulates its activity. Using Co-immunoprecipitation (Co-IP) assay we discovered that CDK9 associates with BRG1 endogenously in colon cancer cells. We tested the association of these proteins more rigorously by transiently over-expressing either FLAG-tagged or GFP-tagged CDK9 in HEK293T cells and performed immunoprecipitation using BRG1 antibody. CDK9 was found to co-precipitate with BRG1. We validated this via reciprocal Co-IPs. We performed an in vitro kinase assay using purified CDK9 and BRG1 proteins to demonstrate that CDK9 directly phosphorylates BRG1 and that inhibition of CDK9 leads to reduced phosphorylation of BRG1. We validated these results in vivo in colon cancer cells. Furthermore, our LC-MS/MS data lead to the identification of novel phosphorylation sites in BRG1 following CDK9 inhibition. These findings provide a potential mechanism for the transcriptional repressor activity associated with CDK9 and may be relevant for developing therapies targeting this transcriptional regulator.

Citation Format: Somnath Pandey, Hanghang Zhang, Carlos A. Barrero, Salim Merali, Xavier Graña, Jean-Pierre Issa. CDK9 phosphorylates BRG1 chromatin remodeler [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2995.
Abstract 2999: Low-dose demethylation therapy for the treatment of cisplatin-resistant testicular cancer
Authors: Corbet Andrea , Albany Costantine , Bikorimana Emmanuel , Khan Ema , Rodriguez Jennifer , Christensen Brock C. , Sandusky George , Einhorn Lawrence H. , Freemantle Sarah J. , Spinella Michael J.
Published: August 2018

Testicular germ cell tumors (TGCTs) are the most common cancers of young males. A portion of TGCT patients are refractory to cisplatin. Only 30% of patients refractory to cisplatin respond to salvage therapies while to remainder die from progressive disease. Embryonal carcinoma (EC) are the stem cells of TGCTs. We have found that EC cells were highly sensitive to the DNA methyltransferase inhibitor, 5-aza deoxycytidine (5-aza). As an initial step in bringing demethylation therapy to the clinic for TGCT patients, we evaluated the effects of the clinically optimized, second generation demethylating agent guadecitabine (SGI-110) on EC cells in an animal model of cisplatin refractory testicular cancer. EC cells were exquisitely sensitive to guadecitabine and the hypersensitivity was dependent on high levels of DNA methyltransferase 3B. Guadecitabine mediated transcriptional reprogramming of EC cells included induction of p53 targets and repression of pluripotency genes. As a single agent, guadecitabine completely abolished progression and induced complete regression of cisplatin resistant EC xenografts even at doses well below those required to impact somatic solid tumors. Low dose guadecitabine also sensitized refractory EC cells to cisplatin in vivo. Genome-wide analysis indicated that in vivo antitumor activity was associated with activation of p53 and immune-related pathways and the antitumor effects of guadecitabine were dependent on p53, a gene rarely mutated in TGCTs. Together, these preclinical findings provided the rationale for our recently initiated and promising phase I clinical trial using SGI-110 to treat cisplatin refractory TGCT patients. We discuss our recent genome-wide molecular studies aimed to identify potential mechanism(s) to account for the hypersensitivity of TGCTs to 5-aza including promoter demethylation, p53 activation and dsRNA MDA5/MAVS/IRF7 viral mimicry. We also discuss preliminary findings from our ongoing trial. Our findings suggest that guadecitabine alone or in combination with cisplatin is a promising strategy to treat refractory TGCT patients.

Citation Format: Andrea Corbet, Costantine Albany, Emmanuel Bikorimana, Ema Khan, Jennifer Rodriguez, Brock C. Christensen, George Sandusky, Lawrence H. Einhorn, Sarah J. Freemantle, Michael J. Spinella. Low-dose demethylation therapy for the treatment of cisplatin-resistant testicular cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2999.
Abstract 3002: Genome engineering approaches to generate models of chromosome arm-level cancer aneuploidy
Authors: Taylor Alison Marie , Zhang Xiaoyang , Shih Juliann , Ha Gavin , Gao Galen F. , Berger Ashton C. , Cherniack Andrew D. , Beroukhim Rameen , Meyerson Matthew
Published: August 2018

Aneuploidy, whole chromosome or chromosome arm copy number imbalance, is a near-universal characteristic of human cancers. Although yeast and mammalian models of whole chromosome aneuploidies have been extensively investigated, chromosome arm-level aneuploidies have rarely been modeled. Cancer subtypes are often characterized by tumor-specific patterns of these arm-level copy number alterations; for example, squamous cell carcinomas (SCCs) from different tissues of origin (including lung, esophagus, and bladder) have a pattern of chromosome 3p loss and chromosome 3q gain. Our analysis of 495 lung SCCs found chromosome 3p deletion to be the most frequent genomic alteration, occurring in almost 80% of the tumors and covering the entire length of the chromosome arm. Over two-thirds of chromosome 3p genes showed significantly decreased expression in these samples. Without models of chromosome arm-level alterations, the phenotypic effects of specific aneuploidies in cancer, such as 3p deletion, remain unknown. However, recent advances in genome engineering and targeting of endonucleases allow new approaches to generate chromosomal alterations. Here, we used the CRISPR-Cas9 system to delete one copy of chromosome 3p in vitro. We successfully isolated almost 90 clones of immortalized lung epithelial cells with deletion of the 3p arm, with 8 validated by whole-genome sequencing. Consistent with patient data, expression of 3p genes was also decreased upon deletion. Phenotypic characterization revealed that cells with chromosome 3p deletion initially proliferated more slowly than their siblings. These chromosome 3p-deleted cells had increased G1 arrest, but did not undergo increased apoptosis or cell death. Interestingly, after several passages in culture, the proliferation defect was rescued in chromosome 3p-deleted cells; genome sequencing and karyotype analyses suggested that this was the result of chromosome 3 duplication. With our cellular model of chromosome arm-level aneuploidy, we uncovered a possible selection mechanism that allows aneuploidy tolerance in vitro. We used genome engineering to model chromosome arm-level deletions, providing a robust model that will address a gap in our understanding of aneuploidy in cancer.

Citation Format: Alison Marie Taylor, Xiaoyang Zhang, Juliann Shih, Gavin Ha, Galen F. Gao, Ashton C. Berger, Andrew D. Cherniack, Rameen Beroukhim, Matthew Meyerson. Genome engineering approaches to generate models of chromosome arm-level cancer aneuploidy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3002.
Abstract 3020: An essential role for Argonaute 2 in EGFR-KRAS signaling in pancreatic cancer development
Authors: Shankar Sunita , Tien Jean , Siebenaler Ronald F. , Dommeti Vijaya L. , Zelenka-Wang Sylvia , Juckette Kristin M. , Xu Alice , Mody Malay , Goodrum Andrew , Tsaloff Grace , Apel Ingrid J. , Wang Lisha , Siddiqui Javed , Shi Jiaqi , Kumar-Sinha Chandan , Chinnaiyan Arul
Published: August 2018

KRAS and EGFR have been shown to function as essential mediators of pancreatic cancer development. In addition, KRAS and EGFR have been separately shown to interact with and perturb the function of Argonaute 2 (AGO2), a key mediator of RNA-mediated gene silencing. Here, we employed a genetically engineered mouse model of pancreatic cancer to define the effects of conditional loss of AGO2 in KRASG12D driven pancreatic cancer. Genetic ablation of AGO2 does not interfere with development of the normal pancreas or KRASG12D driven early precursor pancreatic intraepithelial (PanIN) lesions. However, AGO2 loss prevents progression from early to late PanIN lesions, development of pancreatic ductal adenocarcinoma (PDAC), and metastatic progression. This results in a dramatic increase in survival of KRASG12D mutant mice deficient in AGO2 expression. In both mouse and human pancreatic tissues, increased AGO2 expression at the plasma membrane is associated with PDAC progression. Mechanistically, within early precursor PanIN lesions, loss of AGO2 elevates phospho-EGFR levels and activates wild-type RAS, antagonizing KRASG12D activation and PDAC development. Furthermore, we observe that phosphorylation of AGO2Y393 by EGFR disrupts the interaction of wild-type RAS with AGO2, but does not affect the interaction of mutant KRAS with AGO2. Taken together, our study supports a biphasic model of pancreatic cancer development: an AGO2-independent early phase of PanIN formation reliant on EGFR and wild-type RAS signaling, and an AGO2-dependent phase wherein the KRAS-AGO2 interaction is critical to the progression from PanIN to PDAC. A recent study by Phillip Sharp and Tyler Jacks describes a requirement for the oncogenic KRAS-AGO2 interaction in the development of a transplant mouse model of plasmablastic lymphoma, and together these studies substantiate the role of the interaction in KRAS oncogenesis.

Citation Format: Sunita Shankar, Jean Tien, Ronald F. Siebenaler, Vijaya L. Dommeti, Sylvia Zelenka-Wang, Kristin M. Juckette, Alice Xu, Malay Mody, Andrew Goodrum, Grace Tsaloff, Ingrid J. Apel, Lisha Wang, Javed Siddiqui, Jiaqi Shi, Chandan Kumar-Sinha, Arul Chinnaiyan. An essential role for Argonaute 2 in EGFR-KRAS signaling in pancreatic cancer development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3020.
Abstract 304: Dual PI3K/BCL-2 family inhibition in colorectal cancers with Apc and Pik3ca mutations
Authors: Miller Devon D. , Babiarz Christopher P. , Payne Susan N. , Pasch Cheri A. , Clipson Linda , Matkowskyj Kristina A. , Deming Dustin A.
Published: August 2018

Background: Colorectal cancer (CRC) is a leading cause of cancer-related death in the United States. Approximately 20% of human CRCs possess mutations in the PIK3CA gene, resulting in a constitutively active form of phosphoinositide-3 kinase (PI3K). These PIK3CA mutations most commonly occur concomitantly with the loss of adenomatous polyposis coli (APC). Copanlisib is a beta-isoform sparing PI3K inhibitor. Here we examine the response of CRCs with Apc and Pik3ca mutations to copanlisib alone and in combination with navitoclax, a BCL-2, BCL-xL, and BCL-w inhibitor.

Methods: Murine-derived organotypic cancer spheroids (MDOCS) with Apc and Pik3ca mutations generated from transgenic mice were cultured in Matrigel and treated by exchanging feeding media containing desired concentration of each agent over the spheroids. Spheroids were treated with feeding media (control), 200nM ABT263, 200nM copanlisib, or the combination of both treatments. The spheroid culture response was quantified as the median relative change in the sphere diameter, comparing pre- and posttreatment 4x optical microscopic images to those obtained 48 hours post-treatment.

Results: Untreated MDOCS had a median growth in sphere diameter of 137%. ABT263 did not significantly affect growth; however, copanlisib significantly reduced median sphere size by 24.6% (p<0.001) and the combination treatment reduced median sphere size by 33% which was significant to both control and copanlisib only treated spheres (p<0.001 and p=0.014, respectively). Phosphorylation of ribosomal protein S6 and 4EBP1 were suppressed with copanlisib treatment. Induction of apoptosis in these spheres treated with the combination regimen was confirmed with immunofluorescence for cleaved caspase 3 with minimal apoptosis observed in those spheres treated with copanlisib alone.

Conclusion: In this study, we demonstrated the ability of copanlisib alone and combined with ABT263 to cause a marked decrease in sphere size of CRC MDOCS with Apc and Pik3ca mutations. Future tests will examine this novel regimen in vivo and potentially in future clinical trials.

Citation Format: Devon D. Miller, Christopher P. Babiarz, Susan N. Payne, Cheri A. Pasch, Linda Clipson, Kristina A. Matkowskyj, Dustin A. Deming. Dual PI3K/BCL-2 family inhibition in colorectal cancers with Apc and Pik3ca mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 304.
Abstract 3046: Evaluation of pancreatic ductal adenocarcinoma with acidoCEST MRI
Authors: High Rachel A. , Randtke Edward A. , Jones Kyle M. , Pagel Mark D.
Published: August 2018

Introduction: Our goal is to evaluate the role of using extracelluar pH (pHe) as a predictor of pancreatic ductal adenocarcinoma (PDAC) development using a non-invasive, in vivo imaging technique called acidoCEST MRI, to improve early detection of pancreatic tumors.

Methods: Spontaneous PDAC development was initiated by administering 14 caerulein injections over a 62 hour period to a KrasLSL.G12D/+; PdxCre mouse model. Caerulein induces pancreatitis which drives tumor development in the context of a Kras mutation. Animals were imaged with a Bruker BioSpin 7T MRI scanner with an acidoCEST MRI protocol at pre-injection, 1 hour and 48 hours post final injection of caerulein, and weekly until tumors reached a size of 200mm3. During all MR imaging, mice were anesthetized with 2.0% isofluorane, maintained at a respiration rate of 35-40 bpm, and maintained at a body temperature of 37°C. For acidoCEST MR imaging, mice were injected with 370 mg/mL iopamidol (200 μL IV bolus and 400 μL/hr IV infusion) and scanned with a 6 sec saturation time at 3.5 μT, with a 300 ms acquisition time. Pixel-wise parametric maps of pancreatic pHe values were generated via fitting the CEST spectrum with the Bloch-McConnell equations in MATLAB R2016a. Average pancreatic pHe was recorded.

Results: AcidoCEST MRI was successful in acquiring in vivo pHe of normal and tumor pancreatic tissue, both with sufficient uptake of the iopamidol contrast agent. The pHe values for healthy pancreatic tissue ranged from 6.83 to 7.33 with an average of 6.96 (n=14). 1 hour after the last caerulein injection, during pancreatic inflammation, pHe ranged from 6.78 to 7.00, with an average of 6.92 (n=6). Tumors began to reach a size of 200mm3 at 5 weeks post caerulein injections. In tumor tissue, pHe was 6.59 (n=1), demonstrating tumor acidosis.

Conclusions: We have demonstrated that acidoCEST MRI can be used to quantify pHe in healthy pancreatic tissue, pancreatitis, and pancreatic ductal adenocarcinoma. These pHe values will be used to determine if acidity in pancreatitis correlates with future development of PDAC and/or a more aggressive phenotype. Further pre-clinical studies using acidoCEST MRI may be performed to monitor early therapeutic response to pancreatic tumor treatment.

Citation Format: Rachel A. High, Edward A. Randtke, Kyle M. Jones, Mark D. Pagel. Evaluation of pancreatic ductal adenocarcinoma with acidoCEST MRI [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3046.
Abstract 3051: Prognostic value of 18F-FDG PET/CT parameters in patients with primary pulmonary lymphoepithelioma-like carcinoma
Authors: Fang Yueh-Fu , Lin Chun-Yu
Published: August 2018

Introduction Pretreatment tumor metabolic burden, which measured by fluorine-18 fluorodeoxyglucose positron emission tomography/computerized tomography (18F-FDG PET/CT) have been shown to predict outcomes in various malignancies. Epstein-Barr virus (EBV) serology titer in pulmonary LELC is correlated to stage. However, the prognostic value of 18F-FDG PET/CT in patients with pulmonary lymphoepithelioma-like carcinoma (LELC) and the relationship between EBV viral load remained unknown. The current study aims to investigate the prognostic value and association between functional parameters of 18F-FDG PET/CT and serum EBV DNA in patients with pulmonary LELC.

Methods This retrospective study comprised 32 patients with pulmonary LELC who underwent pretreatment 18F-FDG PET/CT between January 2008 and December 2016. The EBV viral load and the functional parameters of 18F-FDG PET/CT were used for survival analysis.

Results The value of pre-treatment serum EBV DNA had significantly positive correlation with whole MTV (r = 0.63, P = 0.0337) and whole TLG (r = 0.77, P = 0.0093). Advanced tumor stage (≥III) and high whole MTV (≥72.58) significantly predicted poor PFS. Multivariate survival analysis for PFS showed that there was a trend toward a lower risk of recurrence in patients with early tumor stage (≤II) (HR = 0.112, 95% CI =0.011-1.117, P = 0.062, Table 3), albeit not significantly so. Advanced tumor stage (≥III), high whole MTV (≥72.58) and high whole TLG (≥278.4) were predictors of poor OS. However, in multivariate survival analysis, none of them were independent predictors for OS. EBV viral load was not prognostic factor for both PFS and OS.

Conclusion Greater whole MTV and whole TLG predicted poorer OS in patients with primary pulmonary LELC. Functional parameter of 18F-FDG PET/CT may provide useful prognostic information. Serum EBV DNA was closely related to whole MTV and TLG, but not a prognostic factor.

Citation Format: Yueh-Fu Fang, Chun-Yu Lin. Prognostic value of 18F-FDG PET/CT parameters in patients with primary pulmonary lymphoepithelioma-like carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3051.
Abstract 3052: Identification and characterization of DPPA2 as a potential cancer stem cell marker in hepatocellular carcinoma
Authors: Yu Dandan , Yan Qian , Zhang Yu , Guo Ling , Wu Chuanyue , Guan Xin-yuan
Published: August 2018

Cancer stem cells (CSC) are a small subpopulation of tumor cells that share many properties with embryonic stem cells, including the ability to differentiate and self-renew. The study of stemness-associated genes might give us a hint on the tumorigenesis and tumor progression. By comparing the expression profiles of human embryonic stem cells (ESC), endoderm, liver progenitors, premature hepatocytes as well as two pairs of non-tumor and tumor tissues of hepatocellular carcinoma (HCC), we found that the gene Developmental Pluripotency Associated 2 (DPPA2) was highly expressed in the stage of ESC, and decreased dramatically along with development, suggesting its role as a stemness associated gene. Analysis of HCC clinical samples showed that elevated expression of DPPA2 was significantly associated with differentiation, TNM stage, the number of tumor nodules and thrombus, as well as poorer prognosis. Functional studies demonstrated that DPPA2 - overexpressed cells displayed enhanced stemness feature, increasing the ability of self-renewal, tumorigenicity and chemo-resistance. We also found that overexpression of DPPA2 could increase the expression of some cancer stem cell markers. RNA-sequencing results suggested that Wnt signaling was abnormally activated after DPPA2 overexpression. Our findings point to a new potential cancer stem cell marker which may provide an attractive therapeutic target for HCC patients.

Citation Format: Dandan Yu, Qian Yan, Yu Zhang, Ling Guo, Chuanyue Wu, Xin-yuan Guan. Identification and characterization of DPPA2 as a potential cancer stem cell marker in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3052.
Abstract 3059: SOX2 is a novel biomarker for poor long-term outcomes in oral cancer
Authors: Zhang Xuefeng , Xu Hao , Sun Chongkui , Liang Xinhua , Deng Peng , Zeng Xin , Chen Qianming
Published: August 2018

Purpose: Sex determining region Y-BOX2 (SOX2), a key regulator of the self-renewal ability of stem cells, plays a role in the initiation and development of head and neck squamous cell carcinoma (HNSCC). However, the association between SOX2 expression and the outcomes of patients with oral squamous cell carcinoma (OSCC) has not been investigated. Thus, in this study, we investigated the possibility of predicting the survival outcomes of patients with OSCC by evaluating SOX2 expression.

Experiment design: First, we analyzed SOX2 expression in patients with OSCC in The Cancer Genome Atlas (TCGA) dataset by a bioinformatics approach. In addition, samples of 219 patients with OSCC from two independent Chinese centers were collected. The median follow-up time and 95% confidence interval (CI) for the cohorts were 36 (25.06, 46.93) months and SOX2 expression in these samples was determined by immunostaining using tissue microarray. The Kaplan-Meier analysis, log-rank test, and Cox proportional hazards regression model were used to determine univariate and multivariate analyses, and hazard ratios for overall survival (OS), respectively.

Results: In TCGA database, amplification of SOX2 was negatively correlated with the OS rate for patients who survived more than 300 days after the first diagnosis. Moreover, 39.7% of the samples from the cohorts showed high SOX2 expression. We found a significant difference in the survival rate between patients with high and low SOX2 expression ranging from 13 to 126 months.

Conclusion: High SOX2 expression can predict poor long-term, but not short-term, survival outcomes in patients with OSCC. Our findings not only indicated that SOX2 may be a novel biomarker for the long-term prognosis of OSCC but also strongly supported the cancer stem cell theory that dysregulation of the self-renewal ability of stem cells may contribute to the development of OSCC.

Citation Format: Xuefeng Zhang, Hao Xu, Chongkui Sun, Xinhua Liang, Peng Deng, Xin Zeng, Qianming Chen. SOX2 is a novel biomarker for poor long-term outcomes in oral cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3059.
Abstract 3062: Ablation of parathyroid hormone-related protein in the triple negative human breast cancer line MDA-MB-231 inhibits its cancer stem cell phenotype
Authors: Li Jiarong , Doré-Savard Louis , Sellin Karine , Camirand Anne , Kremer Richard
Published: August 2018

Parathyroid hormone-related protein (PTHrP) is a pleiotropic hormone involved in a wide range of developmental & physiological processes. It is also dysregulated in advanced cancers where it causes malignancy-associated hypercalcemia & plays a major role in the progression of bone metastases. We have shown previously that PTHrP ablation delays tumor initiation & that it is preferentially expressed in triple negative breast cancer (TNBC).Here we investigated how PTHrP can influence the phenotype of the human TNBC cell line MDA-MB231 using CRISPR/cas 9 knockout technology. We used U6G RNA-Cas9-2A-red fluorescence protein (RFP) vector with a human PTHrP specific guide RNA directed to exon 4(knockout/KO) or an empty vector as control. PTHrP KO cells (RFP+) were isolated using AutoMacs Pro Separator & single cells were exp&ed in 96 well plates. Positive clones were confirmed by DNA sequencing. Real time PCR & immunofluorescence staining confirmed that 5/96 KO clones had between 95-99% decrease in PTHrP expression compared to control cells. We then assessed cancer stem cell (CSC) characteristics of both KO & control cell lines. Mammosphere formation was reduced by over 60% in KO cells. Stem cell phenotype assessed by ALDH1 & CD44+/CD24 low using FACS analysis were significantly reduced by over 30% in KO cells. Cell morphology analysis showed a shift from a mesenchymal phenotype towards an epithelial phenotype. Overall our data show that PTHrP regulates TNBC towards a more aggressive phenotype & suggest that it could be targeted therapeutically.

Citation Format: Jiarong Li, Louis Doré-Savard, Karine Sellin, Anne Camirand, Richard Kremer. Ablation of parathyroid hormone-related protein in the triple negative human breast cancer line MDA-MB-231 inhibits its cancer stem cell phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3062.
Abstract 3065: Role of noncoding RNA miR 146 alpha and let 7c in epithelial mesenchymal transition, proliferation, and cancer stem cell-like transformation analyzed by gene expression studies in a cohort of prostate cancer patients
Authors: Banerjee Hirendra N. , Sarkar Fazlul , Worthington Myla , Hodge Sasha , Verma Mukesh , Mandal Santosh
Published: August 2018

Mir 146 alpha and let 7c are considered tumor suppressor miRs and are responsible for downregulating polycomb repressor proteins like EZH2, SUZ12, etc., and thereby prevent epithelial-mesenchymal transition (EMT),proliferation, spheroid formation and metastasis in prostate cancer cells. In this study, we investigated the role of these microRNAs in a cohort of 105 patients, both White (CA) and African American (AA), by gene expression studies using real-time PCR techniques. Our results showed definite downregulation of these noncoding RNAs in the cDNAs obtained from the matched biopsy samples of normal and cancer tissues. We further transfected these miR full-length constructs in PC3 prostate cancer cell lines and validated their effects by downregulation of their target 3'UTR target mRNAs. Our results showed decrease in EMT markers ALDH, increase in EMT marker E-cadherin, decrease in cell proliferation and spheroid formation; fluorescence microscopy studies showed a decrease in CD44-positive cells in the spheroids, signifying a possible hindrance in the growth of cancer stem cells (CSCs). Thus, miR 146 alpha and let7c could be ideal targets for diagnosis, prognosis and therapeutic intervention.

Citation Format: Hirendra N. Banerjee, Fazlul Sarkar, Myla Worthington, Sasha Hodge, Mukesh Verma, Santosh Mandal. Role of noncoding RNA miR 146 alpha and let 7c in epithelial mesenchymal transition, proliferation, and cancer stem cell-like transformation analyzed by gene expression studies in a cohort of prostate cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3065.
Abstract 3066: Chemotherapy-induced GSTO1 interacts with ryanodine receptor RYR1 to trigger Ca2+-dependent breast cancer stem cell enrichment
Authors: Lu Haiquan , Semenza Gregg
Published: August 2018

Breast cancer stem cells (BCSCs) play a critical role in tumor recurrence and metastasis. Exposure of breast cancer cells to chemotherapy leads to an enrichment of BCSCs. Here, we demonstrate that chemotherapy induces the expression of glutathione S-transferase omega 1 (GSTO1), which is dependent on hypoxia-inducible factor 1 (HIF-1) and HIF-2. Knockdown of GSTO1 expression abrogates carboplatin-induced BCSC enrichment, decreases tumor initiation and metastatic capacity, and delays tumor recurrence after chemotherapy. GSTO1 interacts with ryanodine receptor RYR1 and promotes calcium release from endoplasmic reticulum. Increased cytosolic calcium levels activate PYK2 → SRC → STAT3 signaling, leading to increased expression of pluripotency factors and BCSC enrichment. HIF inhibition blocks chemotherapy-induced GSTO1 expression and BCSC enrichment. Combining HIF inhibitors with chemotherapy may improve clinical outcome in breast cancer.

Citation Format: Haiquan Lu, Gregg Semenza. Chemotherapy-induced GSTO1 interacts with ryanodine receptor RYR1 to trigger Ca2+-dependent breast cancer stem cell enrichment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3066.