bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2423: Discovery of ZN-e4, an irreversible EGFR-TKI with potent anti-tumor activity in EGFR mutant non-small-cell lung cancer
Authors: Li Jiali , Abraham Sunny , Ma Jianhui , Huang Peter Q. , Bunker Kevin D. , Doñate Fernando , Samatar Ahmed A.
Published: July 2021

Small molecule tyrosine kinase inhibitors against the epidermal growth factor (EGFR) have made significant impact in the treatment of advanced non-small-cell lung cancer (NSCLC) with activating EGFR mutations. Although the first and second-generation EGFR inhibitors have remarkably improved survival in advanced EGFR mutant NSCLC patients, most of the patients develop acquired resistance. The gatekeeper mutation (T790M) is the most common acquired resistance mechanism to the first and second-generation EGFR inhibitors. To overcome the T790M acquired resistance, third-generation EGFR inhibitors, such as osimertinib, were developed. However, additional mutant selective EGFR inhibitors with improved toxicity profile are still needed as osimertinib treatment produced incidence of adverse events, such as diarrhea and skin rush. Here, we describe the identification and characterization of ZN-e4, an orally bioavailable, selective, irreversible third generation EGFR inhibitor. ZN-e4 selectively inhibited the kinase activity of several mutated forms of EGFR, including L858R, T790M/L858R, and Exon19 del in biochemical assay. In cell-based assays, ZN-e4 demonstrated a 20-40-fold selectivity ratio for mutant EGFR forms over the wild-type form thus minimizing the potential for on target toxicity. ZN-e4 potently inhibited the proliferation of NSCLC cell lines harboring EGFR activating and T790M mutation and induced tumor regression in small and large tumors with activating EGFR mutations in preclinical human NSCLC xenograft models. Taken together, our data suggest that ZN-e4 is a potent and selective third generation EGFR inhibitor. Currently, ZN-e4 is in a Phase I clinical trial in patients with EGFR mutant NSCLC showing clinical activity and encouraging toxicity profile.

Citation Format: Jiali Li, Sunny Abraham, Jianhui Ma, Peter Q. Huang, Kevin D. Bunker, Fernando Doñate, Ahmed A. Samatar. Discovery of ZN-e4, an irreversible EGFR-TKI with potent anti-tumor activity in EGFR mutant non-small-cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2423.
Abstract 2451: A novel single domain antibody targeting TIGIT for cancer use in combination therapies
Authors: Hua Botong , Yang Ming , Xue Jie , Dong Chen , Mao Yi-Ting , Li Ou , Cheung Eric , Issafras Hassan , Xu Wenfeng , Jiang Weidong
Published: July 2021

T-cell immunoglobulin and ITIM domains (TIGIT) has emerged as another popular checkpoint receptor that negatively regulates T-cell functions. TIGIT is upregulated by immune cells, such as activated T cells, natural killer cells, and regulatory T cells. TIGIT binds to two ligands, CD155 (PVR) and CD112 (PVRL2, nectin-2), that are expressed by tumor cells and antigen-presenting cells in the tumor microenvironment. Beyond CTLA4 and PD1, TIGIT therapies recently demonstrated great combo potential in the clinic along with well-tolerated toxicity profile. Here we present HLX53, a novel single domain antibody (sdAb) targeting TIGIT with differentiated format, binding epitope, and functional activity. HLX53 binds to TIGIT and blocks CD155 and CD112 with sub-nanomolar affinity. In mixed lymphocyte reaction assay (MLR), HLX53 significantly increased IL2 secretion compared to Tiragolumab and Vibostolimab analogues. HLX53's IL2 induction seems to require an adequate bridging effect between T-cell and antigen-presenting cell via Fc-FcγR engagement, further promoting the maturation of antigen-specific T-cell. In vivo, HLX53 exhibits a better tumor inhibition than Tiragolumab analogue and shows synergy in combination with anti-PD-L1 antibody in MC38 model. In addition to its unique epitope/MOA, HLX53 being a sdAb has a shorter half-life and thus potentially a better tumor penetration and a differentiated PK/PD profile. Understanding pharmacokinetic and pharmacodynamic relationships enables a dosing regimen providing adequate target coverage and superior tumor eradication.

Citation Format: Botong Hua, Ming Yang, Jie Xue, Chen Dong, Yi-Ting Mao, Ou Li, Eric Cheung, Hassan Issafras, Wenfeng Xu, Weidong Jiang. A novel single domain antibody targeting TIGIT for cancer use in combination therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2451.
Abstract 2462: A combination of IL7Rα and NRAS mutations up-regulates Bcl-2 and cMyc levels leading to formation of T-cell acute lymphoblastic leukemia
Authors: Winer Hila , Rodrigues Gisele , Li Wenqing , Hixon Julie , Durum Scott K.
Published: July 2021

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive leukemia derived from T-cell precursors. With current treatments, survival rate is high, but the treatments are highly toxic with severe side effects. In addition, relapse is relatively common in T-ALL and is exceptionally difficult to salvage with hematopoietic stem cell transplant which is essentially the only treatment. Thus, a better understanding of T-ALL etiology and subtypes is required to develop the warranted improved therapies. Individual mutations in IL7Rα and RAS pathways have been previously shown to be prevalent in T-ALL and especially in relapsed patients. However, it is not fully understood how these mutations are involved in disease origin and progression. In addition, we have previously shown that mutations in either IL7Rα or NRAS alone are not sufficient to induce T-ALL. Nevertheless, a combination of both causes severe T-ALL in mice which can be ameliorated by IL7Rα and NRAS signaling inhibition. To better understand how this combination can be utilized to understand disease etiology, we have tested for combinations of mutations that resulted in varying expression levels of the mutated proteins. Our results revealed that a specific ratio between IL7Rα and NRAS expression is necessary to generate T-ALL in mice. Transplanting transduced lymphocyte progenitors into RAG-/- immune-deficient mice allowed us to find an optimal order of the two oncogenes in a polycistronic vector that leads to severe T-ALL. A comparison of transplants from several arrangements of oncogenes in the vector enabled us to screen for potential regulatory pathways that are important for disease progression in vivo by analyzing the cancer cells' transcriptome and proteome. We found that the disease is characterized by a significant increase in IL7Rα-mediated BCL-2 expression, and an increase in c-Myc protein levels, via NRAS signaling. Our results are confirmed by induction of a similar phenotype with a combination of overexpressed WT c-Myc and mutant IL7Rα, which caused severe leukemia as early as 16 days post-transplant. Taken together, we developed a robust model to study T-ALL in mice, shed light on novel pathways of oncogenesis and discovered new targets for intervention that could lead to better therapeutic development.

Citation Format: Hila Winer, Gisele Rodrigues, Wenqing Li, Julie Hixon, Scott K. Durum. A combination of IL7Rα and NRAS mutations up-regulates Bcl-2 and cMyc levels leading to formation of T-cell acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2462.
Abstract 2473: NR4A1 suppresses cancer replication stress through R-loop-dependent inhibition of immediate early gene transcriptional elongation
Authors: Guo Hongshan , Golczer Gabriel , Maheswaran Shyamala , Lawrence Michael S. , Haber Daniel A.
Published: July 2021

Deregulation of oncogenic proliferative signals triggers replication stress in cancer cells to which they must adapt. Immediate early genes (IEGs), identified by their rapid stress-induced transient bursts of expression, are critical to integrating downstream signaling pathways. In studying tumor initiation by patient-derived breast cancer cells, we observed acquisition of open chromatin domains at the genebody and 3'-UTR of IEGs, uniquely across the genome. Through in vivo and in vitro modeling, we show that the IEG and orphan nuclear receptor NR4A1 localizes across multiple IEG genebodies, where it binds to RNA Pol II, arresting transcriptional elongation and generating extensive R-loops and accessible chromatin. Acute stress promptly removes NR4A1 from IEG genebodies, triggering immediate release of their poised transcripts. In breast cancer cells, NR4A1 overexpression increases tumorigenesis; conversely, its deletion leads to uncompensated replication stress, chromosomal instability and mitotic catastrophe, driven by deregulation of its IEG target FOS. A large fraction of primary breast and other cancers exhibit open genebody chromatin at IEGs, consistent with preserved NR4A1 function. Thus, NR4A1 mediates a novel transcriptional elongation checkpoint, unique to stress-induced genes and required for their rapid bursts of expression. Cancers that have retained this mechanism in adapting to chronic replication stress may be dependent on NR4A1 for proliferation.

Citation Format: Hongshan Guo, Gabriel Golczer, Shyamala Maheswaran, Michael S. Lawrence, Daniel A. Haber. NR4A1 suppresses cancer replication stress through R-loop-dependent inhibition of immediate early gene transcriptional elongation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2473.
Abstract 2505: Fibrinogen suppresses tumor growth and metastasis in lung cancer
Authors: Wang Xinran , Swartz Mary Katherine , Liu Runhua
Published: July 2021

About 80% to 85% of lung cancers are non-small cell lung cancers (NSCLC), including lung adenocarcinoma (LUAD, 40% of lung cancers) and lung squamous cell carcinoma (LUSC, 25% to 30% of lung cancers). Fibrinogen is an extracellular matrix protein composed of three polypeptide chains with fibrinogen alpha (FGA), beta (FGB), and gamma (FGG). A recent genome-scale screening reveals that loss of FGA affects the acceleration of tumor growth and metastasis of lung cancer, but the mechanism remains elusive. Based on our bioinformatics analysis, genetic alterations of FGA are unlikely to be a frequent event in human lung cancers. However, our expression analysis showed a low expression of FGA in human lung cancer tissues, including LUAD and LUSC. DNA hypermethylation in the promoter region of FGA is correlated with low expression of FGA in human LUAD tissues. Furthermore, FGA knockout promotes but the administration of FGA inhibits LUAD cell growth, migration, and invasion, as well as tumor colonization in the lung. Our functional analysis revealed the FGA-mediated regulation of tumor growth and metastasis through apoptosis and EMT is also involved in the integrin-AKT signaling pathway in LUAD cells in vitro and xenograft tumor model in vivo. These data suggest that FGA may play a suppressive role in LUAD cells to inhibit tumor growth and metastasis through induction of apoptosis and inhibition of EMT. In LUAD cells, FGA can bind integrin α5 and reduce phosphorylation of AKT, leading to an inhibition of mTOR signaling. The administration of FGA may provide a new therapeutic approach to inhibit LUAD cell growth and metastasis. However, FGA may also affect TME cells in vivo, such as endothelial cells, leading to the various roles of FGA in tumor growth and metastasis.

Citation Format: Xinran Wang, Mary Katherine Swartz, Runhua Liu. Fibrinogen suppresses tumor growth and metastasis in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2505.
Abstract 2523: Novel genomic characterization in late stage colorectal cancer
Authors: Li Jianxia , Wu Qianchao , Zhang Jianwei , Hu Huabin , Cai Yue , Lin Jiayu , Liu Jun , Deng Yanhong
Published: July 2021

Introduction: Colorectal cancer patients with high-level microsatellite instability benefit more from immune checkpoint inhibitor therapy, but they only account for around 15% of all colorectal cancer patients. The remaining patients are still lack of effective therapeutic biomarkers. For patients in late stage without optimal treatment, it is essential to find novel biomarkers which can be used to select appropriate therapies and therefore improve patients' overall survival.

Methods: We used whole-exome sequencing to analyze 114 colorectal cancer samples. The samples included 86 primary late stage tumors and 28 metastatic tumors from liver, lung and other organs. The primary samples were further divided into different groups based on their tumor location (sideness) and microsatellite status (MS) since these indications are of great significance in clinical presentation and treatment. We then assessed somatic genomic lesions, copy number variations, germline gene alterations and mutational signatures in the above three pairs of comparisons respectively (primary vs. metastatic, right- vs. left-sided, MS instable vs. stable).

Results: There were significant differences between the analyzed pairs. For the primary and metastatic samples, the most prominent difference was the copy number variation which happened in 25 genes in the metastatic samples and only one gene in the primary samples (gain of IL12) (p = 0.036). For the right- and left-sided comparison, SNP/Indel mutations were the most prominent. They happened more frequently in the right-sided than the left-sided tumors and those are rare genes in colorectal cancer, including BCL11A (p = 0.018), DICER1 (p = 0.038), NR4A3 (p = 0.004), NIN (p = 0.008) and FBXW7 (p = 0.019). For the MSI-MSS comparison, tumor mutation burden (TMB) stands out high in the MSI group compared to the MSS group (p < 0.0001). In addition, dozens of significantly mutated genes were observed in the MSI samples (p < 0.0001), such as KMT2B, ACVR2A, KMT2D, ASXL1, TCF7L2 and etc. However, TP53 occurred mainly in the MSS patients (p = 0.0007).

Conclusion: Our study enables a deeper understanding of the genomic characterization of colorectal cancer from an integrated view. Copy number variations, gene mutations, and TMB were found to be the most significant differences between the comparison groups of primary vs. metastatic samples, left vs. right sided samples, and MSI vs. MSS samples respectively. Genomic differences between metastatic and primary samples may be potential therapeutic targets for metastatic colorectal cancer.

Citation Format: Jianxia Li, Qianchao Wu, Jianwei Zhang, Huabin Hu, Yue Cai, Jiayu Lin, Jun Liu, Yanhong Deng. Novel genomic characterization in late stage colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2523.
Abstract 2529: Specific racial CYP2R1 correlation with circadian rhythm genes in prostate adenocarcinoma
Authors: Adelani Isaacson Bababode , Rotimi Solomon Oladapo , Yates Clayton , Campbell Moray
Published: July 2021

Introduction: Vitamin D in its hormonal form, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) binds to the vitamin D receptor (VDR) to regulate genes, for example, in skeletal mineralization. However, it also has other potent biological functions in regulating apoptosis, proliferation, and inflammation. In carcinogenesis, 1,25(OH)2D3 may be exploited to regulate these crucial pathways. It is also clear that a frequent cancer disparity exists amongst African American (AA) men with prostate cancer compared to European Americans (EA). AA men show a higher incidence rate and two to three times increased risk of mortality than EA counterparts. Various groups have suggested that 1,25(OH)2D3 levels and/or VDR functions are risk factors linked with increased prostate cancer incidence in AA men. Incidentally, reports showed that VD plays a crucial role in regulating circadian rhythm (CR). There is, therefore, a need to understand and evaluate 1,25(OH)2D3-dependent CR regulation and the association with racial disparity in prostate cancer. This study aimed to determine if there are differentially expressed VD metabolic enzymes in AA and EA and evaluate if the differential expression correlates with CR genes.

Methods: The Cancer Genome Atlas Research Network (TCGA), 2015 database was queried for expression of VD metabolizing enzymes and CR genes. The search was carried out on prostate adenocarcinoma expressions of AA and EA. VD metabolizing enzymes queried are CYP2R1, CYP24A1, CYP27B1, CYP27A1, while CR genes queried include ARNTL, CLOCK, CRY1, CRY2, CSNK1E, NPAS2, PER1, PER2, PER3, and TIMELESS. Prostate adenocarcinoma racial differential expressions of AA and EA were evaluated, and a correlation study was done using the Pearson correlation.

Results: VD metabolic enzyme, CYP2R1, and CR gene, ARNTL were significantly upregulated in AA compared to EA counterparts. Although CYPR1 correlates negatively with CLOCK, CRY2, and PER3 in both races, CYPR1 specifically showed a positive correlation with CR gene CRY1 in EA and negative correlations with CR genes NPAS2 and CSNK1E in AA. However, a significant correlation between CYP2R1 and ARNTL in EA and AA was not observed.

Conclusion: The data suggest a relationship between racial influence and prostate cancer associated with VD metabolism and CR regulation. Hence, it is crucial to elucidate CYP2R1 regulation in prostate cancer related to VD levels and CR regulation, especially with a focus on racial disparities.

Citation Format: Isaacson Bababode Adelani, Solomon Oladapo Rotimi, Clayton Yates, Moray Campbell. Specific racial CYP2R1 correlation with circadian rhythm genes in prostate adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2529.
Abstract 2543: Venue-based recruitment to increase colorectal screening rates using fecal immunochemical test in Essex County, New Jersey
Authors: Alzate-Duque Luis , Valera Pamela , Cueto Vivian , Shome Ashna , Natale-Pereira Ana
Published: July 2021

Background: Overall, Essex County, New Jersey's age-adjusted prevalence for completion of colorectal cancer screening is 71.5%; however, Black and Latinx residents have a lower colorectal cancer screening rate of 65%. To increase urban residents' colorectal screening rates, we used venue-based recruitment to educate the community about fecal immunochemical testing.

Methods: Education about fecal immunochemical testing was implemented at community-based events following a colorectal cancer education session. These sessions were carried out in English, Spanish, and Portuguese. Eligibility criteria included the following: (1) between the ages of 45-85 and (2) not current with U.S. Preventive Services Task Force recommended colorectal cancer screening. Eligible participants who agreed to participate were provided a fecal immunochemical testing kit and instructed to complete these kits to be returned within two weeks. Patient navigators followed up with study participants to explore barriers to completion and facilitate the fecal immunochemical testing kit's timely return.

Results: Approximately 132 participants received the fecal immunochemical testing kit, and 55% were returned. On average, participants who received the fecal immunochemical testing kit were at least 60 years of age, 11% were men, 71% indicated no primary care provider, 72% reported no health insurance, and 81% reported no prior colorectal cancer screening. Of the 55% of the fecal immunochemical testing kit that was returned, 9 (12%) were positive for occult blood, and two diagnostic colonoscopies were completed. Participants noted several barriers to completing and returning the fecal immunochemical testing kit. They noted the following barriers: misplaced or loss of fecal immunochemical testing kit, limited time, and perceived comfortability of handling a stool sample.

Discussion: Targeting study participants at community-based events may increase access to colorectal screening for underserved populations. Barriers to colorectal cancer screening could be mitigated by co-locating colorectal cancer screening education in the community.

Citation Format: Luis Alzate-Duque, Pamela Valera, Vivian Cueto, Ashna Shome, Ana Natale-Pereira. Venue-based recruitment to increase colorectal screening rates using fecal immunochemical test in Essex County, New Jersey [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2543.
Abstract 2577: Metaboendocrine and inflammatory correlates of tumor growth following caloric restriction and vertical sleeve gastrectomy in a mouse model of breast cancer
Authors: McFarlane Tori L. , Camp Kristina Kalevas , Glenny Elaine M. , Rezeli Erika , Coleman Michael F. , Hursting Stephen D.
Published: July 2021

Breast cancer is the second leading cause of cancer-related deaths in women living in the United States, and obesity is a well-established breast cancer risk and progression factor. Identifying interventions that effectively break the obesity-cancer link is therefore of great importance. This preclinical project aims to compare circulating cytokine and metaboendocrine hormone levels in formerly obese mice following dietary and surgical weight loss to identify serum markers potentially contributing to differential tumor mass outcomes. 20 control female C57BL/6 mice were maintained on a 10 kcal% fat diet throughout the study. All other mice were placed on a 60 kcal% diet for 15 weeks to promote diet-induced obesity (DIO), then randomized to receive either: a) vertical sleeve gastrectomy (VSG) with concurrent switch to control diet (16 mice); b) sham surgery and continuation of DIO regimen (18 mice); c) sham surgery with switch to a chronic calorie restricted (CCR; 30% daily calorie reduction) regimen (16 mice); or d) sham surgery with switch to an intermittent calorie restricted (ICR; 14% calorie reduction 5 days per week, 70% calorie reduction 2 non-consecutive days per week) regimen (19 mice). Following 10 weeks of weight loss interventions, serum from fasted animals was collected, and glucose (by glucometer), cytokines (by BioRad Mouse Cytokine 23-plex panel on a BioRad MAGPIX Instrument), and hormones (BioRad Mouse Diabetes 8-plex panel) were analyzed to characterize the systemic metaboendocrine and inflammatory environment immediately prior to orthotopic transplantation of E0771 mammary cancer cells. Surgical or dietary weight loss reduced serum cytokines that are classically induced by obesity, including interleukin 6 (IL-6), interleukin 2 (IL-2), and tumor necrosis factor alpha (TNFα), compared with DIO mice. Compared with VSG mice, only circulating chemokine ligand 13 (CXCL13) was significantly lower in serum from both CCR and ICR mice. Moreover, CCR and ICR mice displayed significantly lower fasting blood glucose levels and circulating plasminogen activator inhibitor-1 (PAI-1) compared with VSG mice. Therefore, these data suggest that decreased circulating CXCL13, PAI-1 and/or decreased fasted blood glucose may contribute to the superior antitumor effects of CCR and ICR versus VSG.

This research was supported by R35CA197627 to S. Hursting.

Citation Format: Tori L. McFarlane, Kristina Kalevas Camp, Elaine M. Glenny, Erika Rezeli, Michael F. Coleman, Stephen D. Hursting. Metaboendocrine and inflammatory correlates of tumor growth following caloric restriction and vertical sleeve gastrectomy in a mouse model of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2577.
Abstract 2582: Gnetin C inhibits reactivated AR signaling in advanced prostate cancer
Authors: Deabel Rabab M. Al , Zhang Joyce , Puaar Anand , Kumar Avinash , Levenson Anait S.
Published: July 2021

The activation of androgen receptor (AR) is a key process in the development and progression of prostate cancer (PCa). After significant clinical response to androgen-deprivation therapy, patients with advanced PCa regularly relapse with more aggressive castrate-resistant PCa, in which AR and its oncogenic variants are reactivated. Therefore, there is an urgent necessity to develop therapeutic strategies that effectively suppress the tumor promoting signals associated with AR action in castrate-resistant PCa. Dietary stilbenes found in grapes and various berries are promising anticancer agents with multiple cellular targets, including AR. Particularly, we previously demonstrated that resveratrol (Res) and its naturally occurring analogs, pterostilbene and piceatannol, can decrease expression of AR in LNCaP and 22Rv1 cells, therefore presenting an attractive potential for stilbenes as promising pharmacologically safe agents in managing PCa. Gnetin C, a Res-dimer found abundantly in melinjo (Gnetum gnemon) plant, which possesses potent biological properties compared to Res and analogs due to its improved pharmacokinetics, is shown to be safe in healthy volunteers. Here, for the first time, we examine the efficacy of Gnetin C in targeting both full-length and ligand-independent AR splice variant (AR-V7) expressed in the castrate-resistant 22Rv1 cells. First, we found that Gnetin C shows significantly more potent cytotoxic effect in 22Rv1 cells compared to Res and Pter. Immunoblot analysis demonstrated that Gnetin C inhibited expression of both full-length (100 kDA) and truncated (80 kDA) AR-V7 in a dose-dependent manner and, importantly, with significantly higher efficacy than Res and Pter when treated with the same dose (50 μM). In addition, Gnetin C used in twice lesser dose (25 μM), showed substantially more inhibitory effect compared to flutamide and enzalutamide (50 μM), two known AR antagonists used in clinic. Moreover, since neuroendocrine trans-differentiation (NED) is associated with AR-dependent mechanisms and enzalutamide resistance in PCa, we evaluated the effects of Gnetin C on SYP and CHGA. Ongoing in vivo studies using transgenic mice with activated AR signaling treated with Gnetin C are in progress. Taken together, we propose that Gnetin C is a lead compound among stilbenes for effectively blocking AR reactivation in PCa and may potentially have noteworthy therapeutic implications against advanced PCa.

Citation Format: Rabab M. Al Deabel, Joyce Zhang, Anand Puaar, Avinash Kumar, Anait S. Levenson. Gnetin C inhibits reactivated AR signaling in advanced prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2582.
Abstract 2595: Cancer cachexia is mediated by the suppression of PGC1-alpha expression in the skeletal muscle vasculature
Authors: Kim Young-Mee , Mancinelli Georgina , Grippo Paul , Rehman Jalees
Published: July 2021

Background: Cancer patients experience cachexia which is characterized by extensive skeletal muscle wasting that worsens the quality of life and increases mortality. However, there are no approved treatments that can effectively counteract cancer cachexia. Prior research has focused on the changes within the muscle tissue but little is known about the role of the muscle vasculature in mediating cancer cachexia. Vascular endothelial cells (ECs) are essential for maintaining tissue perfusion, nutrient supply and preventing inappropriate transmigration of immune cells into the tissue. We therefore hypothesized that endothelial dysfunction in the skeletal muscle results in the development of cachexia in cancer. The transcriptional co-activator PGC1α (peroxisome proliferation activator receptor-γ coactivator1-α) regulates endothelial health.

Methods and Results: To evaluate whether skeletal muscle EC-PGC1α is modulated in the setting of malignancy, we isolated muscle ECs from control and melanoma bearing mice at 1, 2, and 3 weeks after melanoma implantation. PGC1α expression was significantly decreased in mECs of melanoma bearing mice from early stage (1 week) compared with control mice. Thus, we generated an EC-specific inducible PGC1α deletion mouse model (ECΔPGC1α) to investigate the mechanistic role of EC-PGC1α in cancer cachexia in vivo. Interestingly, vascular density and muscle area were significantly decreased in the gastrocnemius (GC) of ECΔPGC1α mice compared with ECWT mice using an innovative tissue clearing and high-resolution 3D-tissue imaging system. Tumor bearing ECWT mice had decreased GC mass and weight compared with no tumor mice by enhancing cachexia marker genes, MuRF1 and Atrogin1. The tumor bearing ECΔPGC1α mice had further decreased muscle mass and weight, and grip strength than tumor bearing ECWT mice. We assessed the role of EC-PGC1α in the regulation of capillary function in vivo, and observed that ECΔPGC1α mice demonstrated significantly greater vascular leak than ECWT mice.

Conclusion: These data suggest that the presence of melanoma suppresses PGC1α expression in the skeletal muscle endothelium. Endothelial PGC1α, in turn, is essential for maintaining the integrity of the skeletal muscle vascular barrier. Our study suggests that restoring muscle endothelial dysfunction could be a novel therapeutic approach to prevent or reverse cancer cachexia.

Citation Format: Young-Mee Kim, Georgina Mancinelli, Paul Grippo, Jalees Rehman. Cancer cachexia is mediated by the suppression of PGC1-alpha expression in the skeletal muscle vasculature [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2595.
Abstract 2597: Non-clinical studies of systemic delivery of oncolytic virus arms with IL-12 and anti-PD-1 antibody
Authors: Zheng Yanxin , Yan Runbin , Tang Yuxin , Zhan Borui , Huang Yue , Ni Dongyao , Chen Xiaoqing , Zhou Grace
Published: July 2021

Background: Limited success has been reported with intravenous delivery of oncolytic viruses because of dilution of viruses in the blood volume, rapid clearance of viral particles and sequestration in non-target organs. We have reported construction of MVR-T3011, a recombinant oncolytic herpes virus embodies immunotherapeutic genes encoding IL-12 and anti-PD-1 antibody. Intratumoral Injection of MVR-T3011 has entered into clinical stage for the study of its safety and preliminary efficacy. Here we propose systemic delivery of MVR-T3011 by intravenous (IV) injection to treat tumor types that are not easily accessible by local injection.

Methods: The pharmacological activity, safety and biodistribution of MVR-T3011 by intravenous injection have been studied in immune deficient and competent mouse model.

Results: (i) In immune deficient mice, MVR-T3011 is enriched in tumor following tail vein injection. MVR-T3011 inhibits tumor growth of A549 xenograft. (ii) In immune competent mice, MVR-T1013L, the virus backbone carries a reporter gene encodes luciferase was enriched in upper abdomen and thorax 24hr following IV injection. (iii) IV administration of mouse surrogate oncolytic virus MVR-T3855 extended survival of mice in B16-F10 mouse melanoma lung metastasis model, LLC mouse orthotopic lung cancer model and H22 mouse orthotopic hepatocarcinoma model significantly. (iv) IV administration of MVR-T3855 delayed the onset of peritoneal effusion in H22 mouse hepatocarcinoma model significantly. (v) The biodistribution studies showed: following IV injection, tumor viral DNA reached peak level at 24hr, and dropped to baseline at 48hr; Subsequent injection showed similar patterns with lower peak levels. Consistent virus DNA level in the blood was detected without spike of viral DNA in other tissues probably due to non-complete virus genome circulating following virus clearance. Both IL-12 and anti-PD-1 antibody were detected in tissue and/or blood with low level 24hr following injection.

Conclusions: MVR-T3011 is a suitable herpes oncolytic virus agent for intravenous injection through studies of pharmacological activity, safety and biodistribution. The significant finding reported in this article is clinical potential of herpes oncolytic virus for extensive metastatic tumors.

Citation Format: Yanxin Zheng, Runbin Yan, Yuxin Tang, Borui Zhan, Yue Huang, Dongyao Ni, Xiaoqing Chen, Grace Zhou. Non-clinical studies of systemic delivery of oncolytic virus arms with IL-12 and anti-PD-1 antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2597.
Abstract 2638: Developing 3d hydrogel model for patient-derived organoids of metastatic colorectal cancer
Authors: Wei He , Karelehto Eveliina , Dubbin Karen , Sebastian Aimy , Warren Robert , Moya Monica , Loots Gaby , Wheeler Elizabeth , Coleman Matthew
Published: July 2021

The advances in the development of preclinical models for various cancers have tremendously helped study of the biology and genetics of human cancers as well as for development of therapeutics. Recently, patient-derived organoids (PDOs) have emerged as a robust preclinical platform that can provide insight into the patient specific genetic mechanisms, cancer progression and drug susceptibility. We have developed a novel PDO platform by embedding patient-derived organoids in a 3D hydrogel suspension culture. Our previous studies have shown that, when cultured in hydrogel, spheroids derived from cancer cell lines demonstrated upregulated gene expression signatures in relation to migration and angiogenesis compared to cultures in media, suggesting a more hypoxic, nutrient deficient environment. Given that hypoxia and nutrient deficiency are important feathers of solid tumors, the hydrogel environment could provide a good platform for in vitro study of tumor development and resistance to treatment. In the current study, we embedded PDOs derived from liver metastasis of colorectal cancer into the 3D suspension hydrogel culture. The PDOs adapted well in the hydrogel gel environment. We assessed the response of PDOs in hydrogel to anticancer agents, and compared that to those cultured in media. The PDOs cultured in hydrogel showed significantly elevated resistance to the treatments. The IC50s of chemotherapeutic drugs 5-fluorouracil and oxaliplatin are increased by ~5-10 fold when cultured in hydrogel compared to those in media. Further studies through RNAseq analysis revealed differentially activated signaling pathways. In particular, the levels of the CXC ligand family chemokines are significantly up-regulated in the PDOs cultured in the hydrogel. The CXC ligand family chemokines are important immune stimulants that are known to play key role in the chemotaxis and tumor recruitment of immune cells including neutrophil, T-cell and B-cells. Interestingly, the elevated levels of CXC-ligands have been shown to relate to resistance of colorectal cancer against drug treatment such as 5-fluorouracil. Our hydrogel model could help elucidate the mechanisms behind such resistance. Future study will focus on evaluating how well the hydrogel PDO platform can recapitulate tumor microenvironment and its potential in screening for personalized medicine.

Citation Format: He Wei, Eveliina Karelehto, Karen Dubbin, Aimy Sebastian, Robert Warren, Monica Moya, Gaby Loots, Elizabeth Wheeler, Matthew Coleman. Developing 3d hydrogel model for patient-derived organoids of metastatic colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2638.
Abstract 2646: Implication of different anti-angiogenic treatments on in vitro vascular tube formation in triple negative inflammatory breast cancer cell lines
Authors: Caceres Sara , Alonso-Diez Angela , Crespo Belen , ESpinosa Eduardo , Madaruiaga Beatriz , Silvan Gema , Illera Maria J. , Illera Juan Carlos
Published: July 2021

Introduction: Inflammatory breast cancer (IBC) is the most aggressive breast cancer in women and female dogs (IMC, Inflammatory mammary cancer) with a poor prognosis. Both IBC and IMC are highly angiogenic, lymphangiogenic and lymphangioinvasive. The aim of this study was to evaluate the effect of different anti-angiogenic treatments in the in vitro formation of vascular-like structures as well as cell secretion of different angiogenic and lymphangiogenic factors (VEGFA, VEGFC, VEGFD) and interleukin-8 (IL-8) in culture media.

Material and Methods: For in vitro tube formation assay, culture human SUM149 cells and canine IPC-366 cells were divided into a control group, treated with DMSO, and 4 experimental groups treated with 1.5 μM of VEGF, SU5416 (anti-VEGFR, VEGF B20-4.1.1 (anti-VEGF) and celecoxib (NSAID), respectively, for 4 h at 37ºC in 5% CO2 conditions. Images were taken every 2 hours. Incomplete networks were excluded, and vessel-like tube structures were counted using the Image J Angiogenesis Analyzer software. Data were represented as average percentage relative to control ± SD.

Results: VEGF and celecoxib treatment significantly augmented the formation of vascular-like tube structures respect to control group in both cell lines. However, VEGF B20-4.1.1 and SU5416 decreased the formation of vascular-like tube structures but not significantly. Conditionate media of IPC-366 and SUM149-treated cells with VEGF had significantly decreased VEGFA levels. In contrast, celecoxib treatment, reduced VEGFD levels and increased VEGFC in both cell lines. VEGF B20-4.1.1 addition increased VEGFA levels in culture media and SU5416 significantly diminished VEGFD concentrations. No significant differences in IL-8 levels were found for any treatment.

Conclusions: Increased VEGFC levels after celecoxib treatment suggest a switch from a proangiogenic state toward a lymphangiogenic state. Neutralization of VEGF by VEGF B20-4.1.1 enhances the secretion of VEGFA and VEGFC by tumor cells inhibiting angiogenesis and lymphangenesis.

Citation Format: Sara Caceres, Angela Alonso-Diez, Belen Crespo, Eduardo ESpinosa, Beatriz Madaruiaga, Gema Silvan, Maria J. Illera, Juan Carlos Illera. Implication of different anti-angiogenic treatments on in vitro vascular tube formation in triple negative inflammatory breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2646.
Abstract 2663: Determining the role of altered redox metabolism in lung tumorigenesis
Authors: Camai Alex
Published: July 2021

The purpose of this study is to determine the pathways by which short-term cigarette smoke exposure induces expression of the cystine-glutamate antiporter xCT (SLC7A11) and its downstream implications in carcinogenesis. BEAS-2B lung epithelial cells and their tumorigenic counterpart, B39-TL cells, were exposed to cigarette smoke condensate (CSC) for 3-15 days. Cells were also exposed to a range of inhibitors. Erastin and buthionine sulfoximine (BSO) are inhibitors of various steps in the glutathione synthesis pathway, found to be hyperactive in xCT-overexpressing cells. Cells were also exposed to the drug mito-2-hydroxybenzoic acid (mito-2-HOBA), which scavenges isolevuglandins, reactive γ-ketoaldehydes implicated in oxidative stress and carcinogenesis. Expression of xCT and related proteins was measured using Western blotting. Glutathione levels were detected using the luciferase-based GSH-Glo assay (Promega). Oxidative stress was detected using dihydroethidium (DHE) fluorescence. It was found that CSC exposure significantly increased the expression of xCT and SLC1A5, a transporter that potentially works in synergy with xCT, and that tumorigenic B39-TL cells had significantly increased xCT and SLC1A5 expression compared to BEAS-2B cells. In addition, BEAS-2B cells exposed to CSC and a glutathione synthesis inhibitor such as erastin or BSO showed faster depletion of glutathione than cells treated with only inhibitor. Finally, it was found that BEAS-2B cells treated for 3 days with CSC did not show increased levels of superoxide compared to control cells. However, cells treated with CSC and mito-2-HOBA together showed significantly increased superoxide. These data suggest that CSC induces an antioxidant response which is ablated by mito-2-HOBA. This antioxidant response seems to at least partially rely on glutathione synthesis fueled by xCT, as evidenced by inhibitor studies. The response also seems to be activated by isolevuglandins, because removing these molecules significantly raises oxidative stress. The mechanistic link between CSC exposure, isolevuglandin generation, and xCT/glutathione induction will be clarified in further experiments.

Citation Format: Alex Camai. Determining the role of altered redox metabolism in lung tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2663.
Abstract 2672: Semaphorin 7a promotes cellular transformation via activation of pro-survival signaling
Authors: Rutherford Taylor R. , Lyons Traci R.
Published: July 2021

We seek to further our understanding of normal mammary gland biology and determine how pregnancy associated changes in the mammary gland contribute to development of breast cancers. Though pregnancy is well-known to provide a protective effect against breast cancer risk, all women who give birth experience a transient increase in breast cancer risk following each pregnancy. The magnitude and length of this elevated risk is largely determined by a woman's age at first birth and for women over 30 at the time of first pregnancy the protective effect likely never occurs. Postpartum breast cancers (PPBC), defined as breast cancers diagnosed within 10 years of last childbirth, are more than twice as likely to become metastatic and result in death. This devastating diagnosis affects ~12,000 women annually. In 2006, for the first time, the number of women having children in their 30s was greater than the number under 25. Thus, PPBC cases are rising. We have shown that tumor cells and normal adjacent mammary epithelial cells (MECs) in PPBC patients exhibit high levels of semaphorin 7a (SEMA7A) protein expression, and SEMA7A expressing tumors are more metastatic. Thus, we believe that understanding the mechanisms underlying SEMA7A signaling in the mammary gland will lead to novel insights into aggressive PPBC. Our recent data reveal that SEMA7A+ MECs are evident during lactation, decreased during the reversible phase of postpartum mammary gland involution, and peak at involution day three, suggesting that SEMA7A promotes survival cell survival during postpartum glandular regression. Consistent with our hypothesis, we reveal that mammary luminal progenitor cells are decreased in SEMA7A knockout mice and SEMA7A promotes cell survival in cultured MECs. Interestingly, a portion of our SEMA7A KO dams exhibit evidence of lactation failure, suggestive of precocious involution. Thus, we propose that SEMA7A activates pro-survival signaling in MECs during lactation and involution. In support of this we show that exogenous SEMA7A activates pro-survival kinase AKT in a β1-integrin dependent manner. Additionally, we show that sustained signaling by SEMA7A leads to cellular transformation in vivo and in vitro and that SEMA7A KO mice crossed to MMTV-PyMT mice exhibit longer latency, ~250 days compared to 50-100 in controls. Since we also observe that SEMA7A levels in blood correlate with SEMA7A levels in breast cancer patient tumors, our results suggest that SEMA7A is a driver of tumorigenesis that could be safely monitored in postpartum women.

Citation Format: Taylor R. Rutherford, Traci R. Lyons. Semaphorin 7a promotes cellular transformation via activation of pro-survival signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2672.
Abstract 2682: STK11-loss-dependent YAP1-mediated transcriptional activation promotes immune evasion in KRAS-driven lung adenocarcinoma
Authors: Seward David Joseph
Published: July 2021

Why Serine Threonine Kinase 11 (STK11) loss of function (LoF) correlates with anti-PD1 therapy resistance in the context of KRAS-driven lung adenocarcinomas remains unclear and represents a critical outstanding question in the field. To address this, we knocked out STK11 in KRAS-driven human lung adenocarcinoma cell lines and performed RNAseq to identify STK11-loss-dependent differentially expressed genes. Subsequent pathway enrichment analyses implied activation of the HIPPO/YAP1 signaling network occurs in the absence of STK11. Based on work linking YAP1 with transcriptional regulation of cytokine-mediated inflammation and immune-evasion in colorectal cancer and gastric cancer, we wondered whether YAP1 activation might impact anti-PD1 therapy response in KRAS-driven lung cancers lacking STK11. To evaluate this possibility, we applied a YAP1 transcriptional signature to the differentially expressed genes and performed gene set enrichment analysis (GSEA) revealing a strong positive correlation between STK11 LoF and upregulation of YAP1 target genes, most notably induction of IL-6, IL-8 and IL-32. To validate YAP1-mediated transcriptional activation is downstream of STK11 loss, we reasoned we could rescue STK11-loss-dependent YAP1-mediated cytokine induction by genetic disruption of YAP1, or pharmacologic inhibition of YAP1 with verteporfin. STK11/YAP1 double knock-out cell lines express significantly less IL-6, IL-8 and IL-32 compared with STK11 KO lines. Further, inhibition of YAP1 with verteporfin phenocopied YAP1 genetic disruption in these cell lines, changes mirrored at the level of secreted protein. Finally, we demonstrate YAP1 chromatin occupancy is STK11-dependent. Together these data link STK11 LoF with YAP1-mediated transcriptional activation, specifically the upregulation of immune-evasion promoting cytokines including IL-6, IL-8 and IL-32. We posit these STK11-loss-dependent YAP1-mediated tumor-intrinsic changes could result in anti-PD1 therapy resistance and immune-evasion by promoting recruitment of myeloid-derived suppressor cells, neutrophils and T-regulatory cells to the tumor microenvironment. Further, our results indicate that YAP1 antagonism may represent a valid therapeutic approach to circumvent STK11-loss-dependent transcriptional changes and potentially restore sensitivity to anti-PD1 therapy. Elucidating the mechanism(s) linking STK11 with YAP1 transcriptional activation and evaluating the potential for beneficial therapeutic intervention remains the focus of our continuing work.

Citation Format: David Joseph Seward. STK11-loss-dependent YAP1-mediated transcriptional activation promotes immune evasion in KRAS-driven lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2682.