bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2010: SKI-G-801, an AXL kinase inhibitor, blocks metastasis and induces anti-tumor immune responses in various syngeneic cancer models
Authors: Xin Chun-Feng , Kim Sung Eun , Pyo Kyoung-Ho , Jo Ha Ni , Cho Jae Seok , Kim Jae Hwan , Lee Wongeun , Lee Hee Kyu , Kim Jung-Ho , Song Ho-Juhn , Koh Jong Sung , Cho Byoung Chul
Published: August 2019

Introduction: Aberrant AXL expression plays a critical role in cancer cell migration, metastasis and drug resistance. Researchers have revealed that AXL signaling is also over expressed on cells associated with tumor microenvironment. These findings highlight AXL as an attractive drug candidate for targeting tumor evasion and metastasis. Here we present SKI-G-801, a small molecule inhibitor that targets phosphorylation of AXL (IC50 = 20 nM) and its downstream signals.

Methods: Inhibitory effects of SKI-G-801 on cancer viability (MTT and colony formation assay), invasion and migration (trans-well invasion assay) were examined in AXL high-expressing lung cancer cells in vitro. LLC2 lung and 4T1 breast cancer bearing mouse models were established. in addition, C57BL/6 mice were injected intravenously with B16F10 melanoma cells to establish lung metastasis model. Mice were administrated with 30 mg/kg of SKI-G-801 orally before (metastasis model) or after (syngeneic model) tumor injection. To elucidate the involvement of AXL inhibitor on tumor microenvironment, the population of T cells and myeloid cells was analyzed by flow cytometry from the LLC2 tumor.

Results: Treatment of SKI-G-801 showed strong inhibition of cancer migration and invasion, when its direct killing effect on cancer cells was modest. These results were reproduced in vivo test that pretreatment of SKI-G-801 significantly reduced metastatic burden in B16F10 model (p < 0.05). LLC2 and 4T1 tumors were decreased in SKI-G-801 treatment group (p < 0.05), but not in anthemic nude mice. CD3+CD8+ T cell population and memory Tc cells were increased in SKI- G-801 treatment group (p < 0.05). Especially, granzyme B+ Tc and gp70+ tumor specific Tc were increased (p < 0.05). SKI-G-801 increase the helper T cell population; CD3+CD4+ (p < 0.05), and CD44+ memory Th cells (p < 0.01).

Conclusion: SKI-G-801 demonstrates great potential in anti-cancer activity though immune responses. The anti-cancer effects lead to a reversal of the metastatic phenotype in animal model. Our results suggest that SKI-G-801 is a promising drug for prevention against metastatic cancer.

Citation Format: Chun-Feng Xin, Sung Eun Kim, Kyoung-Ho Pyo, Ha Ni Jo, Jae Seok Cho, Jae Hwan Kim, Wongeun Lee, Hee Kyu Lee, Jung-Ho Kim, Ho-Juhn Song, Jong Sung Koh, Byoung Chul Cho. SKI-G-801, an AXL kinase inhibitor, blocks metastasis and induces anti-tumor immune responses in various syngeneic cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2010.
Abstract 202: STAT1 regulates B7H3 mediated angiogenesis in medulloblastoma
Authors: Purvis Ian J. , Avilala Janardhan , Guda Maheedhara R. , Venkataraman Sujatha , Vibhakar Rajeev , Tsung Andrew J. , Velpula Kiran K. , Asuthkar Swapna
Published: August 2019

B7-H3 (CD276), an immune checkpoint member of the B7/CD28 family, plays a key role in the repression of the immune response by cancer cells. B7-H3 is overexpressed on tumor and tumor-associated cells, making it an interesting therapeutic target. B7-H3 also appears to play a role outside of immune evasion, contributing to the progression of cancer via invasion/migration, angiogenesis, and metastasis. Our previous data has confirmed the presence of B7-H3 in highly aggressive Myc+ medulloblastoma (MB) tumors. Data-mining studies revealed that B7-H3 is correlated with Myc expression in Group 3 and 4 MBs, and is associated with worse patient outcomes. miR-29, a tumor suppressor, has been shown downregulating the expression of B7-H3 in various cancers. We have shown that miR-29 can reduce the angiogenesis abilities of D283 and D425 cells by downregulating B7-H3 in vitro. Subsequent RNA-sequencing analysis of miR-29-transfected D283 cells revealed upregulation of STAT1 activity. Immunoblot analysis and real-time PCR of D283 and D425 cells demonstrated increased expression of p-STAT1, when transfected with miR-29 plasmid. Treatment with all-trans retinoic acid induced p-STAT1 expression, with a concomitant decrease in the expression of B7-H3 and MMP-9. This preliminary data revealed a novel role for STAT1 in potentially regulating B7-H3, and consequently, angiogenesis and metastasis in MB. To date, the role of STAT1 in MB progression has not been fully investigated, and so our results provide a new avenue for developing potential treatments for aggressive MB tumors.

Citation Format: Ian J. Purvis, Janardhan Avilala, Maheedhara R. Guda, Sujatha Venkataraman, Rajeev Vibhakar, Andrew J. Tsung, Kiran K. Velpula, Swapna Asuthkar. STAT1 regulates B7H3 mediated angiogenesis in medulloblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 202.
Abstract 2024: Obesity induces breast cancer cell invasion through stromal secretion of IGF-1
Authors: Hillers Lauren , D'Amato Joseph , Chamberlin Tamara , Paderta Gretchen , Arendt Lisa
Published: August 2019

Obese women diagnosed with breast cancer have an increased risk for metastasis, and the underlying mechanisms are not well established. Within the mammary gland, adipose stromal cells (ASCs) are a group of heterogeneous cells with the capacity to differentiate along multiple mesenchymal lineages. ASCs are recruited and activated within tumors, but it is unknown how obesity may influence ASCs in both normal and cancerous tissue. To study the effects of obesity on ASCs, we isolated the stromal vascular fraction from the mammary glands of mice fed either a control diet (CD) or high fat diet (HFD) to induce obesity and plated the cells to select for adherent growth. We observed that obesity increased ASCs proliferation, decreased differentiation potential, and upregulated expression of α-smooth muscle actin, a marker of activated fibroblasts, compared to ASCs from lean mice. To determine how ASCs from obese mice impacted tumor growth, we mixed ASCs isolated from CD- or HFD-fed mice with mammary tumor cells, Met-1 cells, and transplanted them into the mammary glands of lean FVB female mice. Tumors cells mixed with ASCs from obese mice grew significantly larger tumors and had increased invasion into surrounding adipose tissue than tumor cells mixed with control ASCs. To study the effects of factors secreted by ASCs on tumor cell behavior, we collected conditioned media (CM) from lean and obese ASCs and treated Met-1 cells. Compared with lean ASCs, obese ASCs expressed higher levels of insulin-like growth factor-1 (IGF-1), which has been implicated in tumor cell invasion. Met-1 cells treated with recombinant IGF-1 were more invasive than vehicle-treated cells. In addition, Met-1 cells treated with obese ASCs CM supplemented with an IGF-1 neutralizing antibody had significantly reduced invasion, compared to controls. Weight loss induced in obese mice significantly decreased expression of IGF-1 from ASCs and reduced the ability of the ASCs to induce an invasive phenotype. Together, these results suggest that obesity enhances local invasion of breast cancer cells through increased expression of IGF-1 by mammary ASCs, and weight loss may reverse this tumor-promoting phenotype.

Citation Format: Lauren Hillers, Joseph D'Amato, Tamara Chamberlin, Gretchen Paderta, Lisa Arendt. Obesity induces breast cancer cell invasion through stromal secretion of IGF-1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2024.
Abstract 2027: Understanding the role and regulation of newly synthesized Annexin A2 in the progression of breast cancer
Authors: Mahdi Amira F. , Malacrida Beatrice , Nolan Joanne , McGourty Kieran , Lowery Aoife J. , Kiely Patrick A.
Published: August 2019

In Ireland, almost three thousand women are diagnosed with invasive breast cancer every year. This makes it the most common form of malignant tumour found in Irish females and accounts for 17% of all female cancer deaths. Although treatment for breast cancer when diagnosed early is highly effective, for those who develop late stage and metastatic breast cancer, survival rates decline rapidly. As a result, a large effort is being made to understand the mechanisms involved in the progression of breast cancer and identifying the changes that take place during the in-situ to metastatic transition.

Using 2-D and 3-D in vitro models of cancer metastasis, we conducted a mass spectrometry screen to identify proteins that are newly synthesised by breast cancer cells as they migrate towards a growth factor gradient. From this screen, we identified Annexin A2 as a newly synthesised protein. Annexin A2 is a calcium-ion regulated, phospholipid-binding protein, which is involved in cell trafficking, cell-to- cell contact, cell motility and regulation of the cytoskeletal structure. Annexin A2 has been reported to be overexpressed in a range of cancers including breast cancer and has also been reported to contribute to cancer-associated processes such as proliferation, migration and chemoresistance.

While investigating the role of Annexin A2 in the progression of breast cancer, our findings suggest that through modulation of the cell culture environment, subjecting cells to stress conditions and altering growth factor supplementation, that the intracellular expression of Annexin A2 remains relatively constant. However, in breast cancer patients we see dysregulation of Annexin A2 expression at a gene level, which correlates with disease progression. We are currently investigating how alterations in the composition of the extracellular environment, particularly the extracellular matrix, regulates Annexin A2 expression and cellular location.

We believe that delineating the function of newly synthesised proteins such as Annexin A2 has the potential to direct novel anti-cancer therapies aimed specifically at halting the progression of breast cancer. Ultimately, these insights may lead to improvements in survival rates for those affected with this disease.

Citation Format: Amira F. Mahdi, Beatrice Malacrida, Joanne Nolan, Kieran McGourty, Aoife J. Lowery, Patrick A. Kiely. Understanding the role and regulation of newly synthesized Annexin A2 in the progression of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2027.
Abstract 2034: Activation of cancer-associated fibroblasts via the transfer of miR-125b containing extracellular vesicles from tumor cells
Authors: Vu Luyen Tien , Peng Boya , Zhang Daniel Xin , Ma Victor , Grimson Andrew , Cho William C. , Lieberman Judy , Le Minh TN
Published: August 2019

Tumor cells secrete elevated amounts of extracellular vesicles (EVs) as a mean of communication between them and other cells in the tumor microenvironment. Here, we established a series of breast cancer cell lines releasing fluorescent EVs to identify the common cell types that receive tumor EVs within the tumor microenvironment. Among the different cell types, cancer-associated fibroblasts consistently take up the most EVs from cancer cells. Using next generation sequencing, we find that miR-125b is among the top enriched miRNAs in EVs released by mouse isogenic triple-negative breast cancer 4T1 and 4TO7 cell lines. Co-injection of 4TO7 cells with 4T1 EVs results in an upregulation of fibroblast activation in vivo while blockage of miR-125b in 4T1 EVs rescues the effect indicating that EV-delivery of miR-125b is crucial for the fibroblast activation in mouse breast cancer models. Moreover, EVs from human breast cancer cells also contain abundant miR-125b and fibroblasts within the xenografted tumor that take up these EVs gain higher levels of miR-125b and upregulation of cancer-associated fibroblast markers. Both mouse and human fibroblasts that are transfected with miR-125b mimics show an activated phenotype similar to the knockdown of established miR-125b targets. In summary, normal fibroblasts within the tumor microenvironment actively take up the miR-125b-containing EVs from breast cancer cells and develop into cancer-associated fibroblasts.

Citation Format: Luyen Tien Vu, Boya Peng, Daniel Xin Zhang, Victor Ma, Andrew Grimson, William C. Cho, Judy Lieberman, Minh TN Le. Activation of cancer-associated fibroblasts via the transfer of miR-125b containing extracellular vesicles from tumor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2034.
Abstract 205: BBI-608 enhances the activity of chemoradiotherapy in colorectal cancer pre-clinical models
Authors: Nagaraju Ganji Purnachandra , Balney Rajitha , Bethi Shipra R. , Govardhanagiri Sneha , Lesinski Gregory B. Lesinski B. , El-Rayes Bassel F.
Published: August 2019

Background: Chemoradiotherapy is a standard treatment modality for early stage rectal cancer (CRC). The pathologic complete response rate after chemoradiation in CRC remains low at 15%. Given the potential for BBI608 to elicit effects on multiple oncogenic cellular pathways, we hypothesized that BBI608 can sensitize colorectal cell lines to the effects of chemoradiotherapy. The aim of this study was to evaluate if BBI-608 enhances the response of chemoradiotherapy against CRC.

Methods: The combined effects of BBI-608 and chemoradiotherapy [5-FU + ionizing radiation (IR)] were evaluated in CRC cell lines (HCT 116 and HT-29) using Br-dU cell proliferation and clonogenic assays. Effects on the expression of DNA damage and repair (pATM, pATR, Rad51 and γ-H2AX) molecules and angiogenesis (pSTAT-3 and VEGF) pathways were examined by Western blot. Egg CAM assay was also performed to evaluate effects of the drugs on angiogenesis (quantification was performed by AngioQuant software). The in vivo efficacy of BBI-608 alone or combined with 5-FU + IR, was evaluated in nude mice bearing subcutaneous human HCT116 xenograft tumors

Results: The combination of BBI-608 and chemoradiotherapy significantly decreased cell proliferation (p<0.001), colony formation (p<0.001) and inhibited angiogenesis (p<0.001) in CRC cell lines as compared to chemoradiotherapy. BBI-608 decreased angiogenesis as determined by both matrigel plug and egg CAM assays. Immunoblot analysis indicated BBI-608 and chemoradiotherapy also decreased expression of pSTAT-3, MDM2, Rad51 and VEGF while increasing pATM, γ-H2AX and p53, in comparison to chemoradiotherapy alone. In animal models, combined therapy with BBI-608 and 5-FU + IR led to significant inhibition of longitudinal tumor growth as compared to chemoradiotherapy alone (p<0.001). No overt signs of systemic toxicity were evident and animals showed no loss of body weight in any of the treatment groups, indicating the combination was well-tolerated.

Conclusion: These observations provide preclinical proof-of-principle data that BBI-608 can enhance the anti-tumor effects of chemoradiotherapy. BBI608 plus chemoradiotherapy is a rational approach for potential future development in early stage rectal cancer.

Citation Format: Ganji Purnachandra Nagaraju, Rajitha Balney, Shipra R. Bethi, Sneha Govardhanagiri, Gregory B. Lesinski B. Lesinski, Bassel F. El-Rayes. BBI-608 enhances the activity of chemoradiotherapy in colorectal cancer pre-clinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 205.
Abstract 2061: A novel small molecule inhibitor of MDM2-p53 (APG-115) has antitumor activity in gastric adenocarcinoma
Authors: Zhang Lin , Qiuyun Luo , Xianglei Yan , Wan Xueping , Yuan Luping , Zhang Yuxing , Zhou Suna , Pan Wentao , Pan Mengxian , Qiu Miaozhen , Mai Shijuan , Yang Dajun
Published: August 2019

Background: The amplification of Murine Double Minute 2 (MDM2) and mutation of P53 are significant processes in the incidence of gastric cancer. APG-115, a small molecular inhibitor of MDM2-P53, is a novel potential anticancer agent. We aim to investigate the anticancer effect of APG-115 in gastric cancer.

Methods: We selected 87 pairs of gastric cancer tissues (primary tumors and metastatic tissues). Using Immunohistochemistry (IHC) and Fluorescence in situ hybridization (FISH), we examined the expression and amplification of MDM2 and P53. Using MTS, we examined the anti-proliferation activity of APG-115 in five gastric cancer cell lines (AGS, MKN-45, BGC-823, NCI-N87, NUGC-3) by CCK-8 assay. We used western blot analysis and siRNA interference for mechanism exploration to examine the anti-cancer activity of APG-115 in p53 wild type gastric cancer cell lines. Gastric cancer cell xenograft nude mice models were used for in vivo efficacy evaluation.

Results: We examined 87 pairs of gastric cancer tissues in IHC. The results suggested that the primary tumors and metastatic tissues with high expression of MDM2 and P53 have shortened survival. The proliferation inhibition of APG-115 on p53 wild-type gastric cancer cells of AGS and MKN45 was concentration and time dependent. APG-115 induced apoptosis in gastric cancer cells. APG-115 can induced cell-cycle arrest in G1/G0 phase in the p53 wild-type of gastric cancer cells. APG-115 exhibited potent antitumor activity against established human gastric cancer xenografts.

Conclusions: APG-115 can inhibitor tumor growth in p53 wild-type gastric cancer cells by inducing apoptosis and cell cycle arrest both in vitro and vivo. APG-115 can serve as an effective and precise therapeutic strategy for gastric cancer.

Citation Format: Lin Zhang, Luo Qiuyun, Yan Xianglei, Xueping Wan, Luping Yuan, Yuxing Zhang, Suna Zhou, Wentao Pan, Mengxian Pan, Miaozhen Qiu, Shijuan Mai, Dajun Yang. A novel small molecule inhibitor of MDM2-p53 (APG-115) has antitumor activity in gastric adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2061.
Abstract 2063A: Glucolipotoxicity and altered oxidative stress responses in cancer cells
Authors: Al-Nahdi Arwa MT , John Annie , Raza Haider
Published: August 2019

Alterations in energy metabolism, such as aerobic glycolysis and lactic acid production, and mitochondrial bioenergetics are the key metabolic changes associated with increased glucose uptake in cancer cells (Warburg effect). Metabolic adaptation, inflammatory responses and oxidative stress have been implicated in cancer etiology and pathology. Both experimental and epidemiological studies have suggested that caloric restriction is beneficial in reducing the complications of cancer cells. Studies have also suggested that increased availability of energy metabolites, such as glucose and fatty acids, as also seen in obesity and diabetes, which induces inflammatory and oxidative stress responses, may also be key factors in cancer development. In the present study, we have used human hepatoma, HepG2 and rodent pancreatic cancer derived Rin-5F cells to investigate the effects of high glucose (25mM) and high palmitic acid (up to 0.3mM) on cell survival and cell death along with the metabolic, inflammatory and oxidative stress associated alterations in these cells. Our results have shown that both increased glucose and fatty acids induce DNA damage and caspase-dependent apoptosis and mitochondrial respiratory dysfunction. Glucolipotoxicity in these cells, due to increased ROS production and oxidative stress has been suggested to be involved in altering the mitochondrial membrane potential and bioenergetics. Altered Nrf-2/NFk-B/AMPK/mTOR-dependent cell signaling and inflammatory (IL6/PGE2) responses have also been observed when cells were treated with high glucose and palmitic acid. Interestingly, pretreatment with N-acetyl cysteine (NAC, 10mM), a GSH precursor, resulted in partial recovery from the oxidative stress-induced glucolipotoxicity. Our results suggest that the presence of high energy metabolites enhance inflammatory and oxidative stress responses that may be responsible for alterations in cancer cell signaling and metabolism.

Citation Format: Arwa MT Al-Nahdi, Annie John, Haider Raza. Glucolipotoxicity and altered oxidative stress responses in cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2063A.
Abstract 2075: MAPK pathway expression in platinum-treated cancers
Authors: Georgiadis Rebecca A. , Stark Amy , Hummon Amanda B.
Published: August 2019

The Mitogen-Activated Protein Kinase (MAPK) Pathway is a critical cell signaling pathway in normal cell function. It is involved in cell proliferation, cell survival, and differentiation. It is a common pathway that is mutated in many cancers, and drug targets have already been developed and tested in clinical trials for many components of this pathway. Further understanding of how gene expression in this pathway is altered by treatment of chemotherapeutic agents can potentially impact resistance to chemotherapeutic agents. The half-maximal inhibitory concentration (IC50) was found for A549 cultured lung adenocarcinoma cells treated with cisplatin and for DLD1 cultured colorectal adenocarcinoma cells and HCT116 colorectal carcinoma cells treated with cisplatin and oxaliplatin. The IC50 concentration of cisplatin-treated A549 cells was 5.429 µM, of DLD1 cells was 5.017 µM, and of HCT116 cells was 4.42 µM. The IC50 concentration of oxaliplatin-treated DLD1 cells was 37.53 µM, as compared to 10.36 µM for HCT116 cells. Therefore, the HCT116 cell type is more sensitive to both chemotherapies. qPCR was then conducted on platinum-treated A549 cultured cells, DLD1 cultured cells, and HCT116 cultured cells to evaluate expression of 6 MAPK pathway genes: RAF1, MAP2K1, MAPK1, STAT1, CREB1, and LAMTOR3. A different pattern of induced gene expression was observed across all three cell types. The 24 hour time point of cisplatin-treatment of A549 cells demonstrated a consistent upregulation of expression in all genes, which is starkly contrasted with a significant downregulation at the 48 hour time point. In HCT116 cells, cisplatin treatment led to the opposite trend, as there was downregulation at the 18 hour time point and significant upregulation at the 48 hour time point. DLD1 had inconsistent results. This demonstrates that level of expression of genes in the pathway is cell-type dependent and time-dependent. Naringenin is a flavonoid that has been implicated in MAPK signalling. We tested this compound as an inhibitor to determine the effect on platinum induced gene expression in lung and colorectal cells. These results have implications for treatment of multiple cancers, especially lung and colorectal cancer.

Citation Format: Rebecca A. Georgiadis, Amy Stark, Amanda B. Hummon. MAPK pathway expression in platinum-treated cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2075.
Abstract 2077: A novel assay for PARP-DNA trapping provides insights into the mechanism of action (MoA) of clinical PARP inhibitors (PARPi)
Authors: Illuzzi Giuditta , O'Connor Mark J , Leo Elisabetta
Published: August 2019

Treatments with PARPi in cancers with impaired DNA repair mechanisms (i.e. with Homologous Recombination Repair Deficiency, HRD) causes unsupportable genomic instability resulting in tumor cell death. PARPi act via a dual mechanism: 1) they block PARylation activity that normally occurs in response to DNA damage; 2) they trap PARP onto DNA lesions creating potentially cytotoxic PARP-DNA complexes. The longer PARP is inhibited and trapped onto the DNA, the greater the cytotoxic effect of PARPi in preclinical models. However, differences in preclinical PARP trapping potency have not translated into increased clinical efficacy with standard clinical doses used. Therefore, the ability to assess PARP-chromatin trapping in cancer models is critical for understanding the MoA of existing clinical PARPi. To date, this has been achieved by low throughput assays in non-HRD models using high PARPi concentrations and the addition of exogenous DNA damage.

Here, we describe the development of a novel assay, a high throughput in situ cell extraction platform, where PARP-chromatin trapping is monitored by immunofluorescence and can be multiplexed with the analysis of other relevant biomarkers. Our novel assay has several advantages compared to conventional methods: the overall experimental process is simpler and less time consuming with results being quantitative and less error prone. Most importantly, the higher throughput allows a thorough evaluation of PARP1-chromatin trapping kinetics and their effects with dose-response in a time-dependent manner for clinical PARPi following both continuous treatment or after a wash out of drug.

Using this new assay, we tested the kinetics in isogenic cell line pairs (BRCA2-/- and WT) and followed in parallel the appearance of biomarkers of DNA damage (e.g. γ-H2AX). The data have revealed important elements of differentiation between the MoA of clinical PARPi including the important insight that the strongest PARP trapper (talazoparib) has clearly reduced cytotoxic specificity for HRD cells, which likely explains the significantly reduced dose used in the clinic compared to other PARPi. These along with other data presented highlight how this next generation PARP trapping assays can provide important insights into PARPi MoA.

Citation Format: Giuditta Illuzzi, Mark J O'Connor, Elisabetta Leo. A novel assay for PARP-DNA trapping provides insights into the mechanism of action (MoA) of clinical PARP inhibitors (PARPi) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2077.
Abstract 2086: Targeting the MNK effector hnRNPA1 enhances the efficacy of BET inhibitors in cancer cells
Authors: Pham Thao , Stempel Sophie , Shields Mario , Spaulding Christina , Kumar Krishan , Bentrem David , Munshi Hidayatullah
Published: August 2019

Bromodomain and extraterminal domain (BET) proteins are epigenetic readers that regulate gene expression and are involved in cancer pathogenesis. While a number of BET inhibitors are currently in preclinical development or in early phase clinical trials, BET inhibitors show limited single-agent activity. Thus, there is increasing interest in identifying combination regimens to enhance the efficacy of BET inhibitors. Since MNK kinases can enhance the efficacy of BET inhibitors in vitro and in vivo, in this report we evaluated whether targeting effectors downstream of MNK kinases can enhance the efficacy of BET inhibitors. We show that there is co-expression of the BET protein BRD4 and the MNK effector hnRNPA1 in human tumors. We show that hnRNPA1 knockdown can potentiate the effects of BET inhibitors, with enhanced apoptosis and suppression of proliferation and sphere-forming ability by cancer cells. We also show that the plant flavonoid Quercetin, which reduces hnRNPA1 protein levels in cancer cells, can enhance the efficacy of BET inhibitors. Co-treatment with BET inhibitors and Quercetin results in enhanced apoptosis, further suppression of proliferation, and decreased sphere-forming ability by cancer cells. Significantly, Quercetin synergizes with BET inhibitors at suppressing tumor growth in vivo. Together, these results demonstrate that targeting the MNK effector hnRNPA1 can enhance the efficacy of BET inhibitors, and we identify combination therapy with BET inhibitors and Quercetin for the treatment of cancer patients.

Citation Format: Thao Pham, Sophie Stempel, Mario Shields, Christina Spaulding, Krishan Kumar, David Bentrem, Hidayatullah Munshi. Targeting the MNK effector hnRNPA1 enhances the efficacy of BET inhibitors in cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2086.
Abstract 209: Metastatic colonization in the perivascular niche: A mechanotransduction perspective
Authors: Er Ekrem Emrah , Tello-Lafoz Maria , Hu Jing , Huse Morgan , Massagué Joan
Published: August 2019

Metastases are responsible for majority cancer related deaths. Disseminated tumor cells (DTCs) gain a diverse array of metastatic traits in order to adapt to and survive within different microenvironments, making them very difficult to therapeutically target. Remarkably, regardless of the secondary organ, DTCs survive and thrive in perivascular niches. Using xenograft and syngeneic models of metastasis in mouse, we found that upon extravasation, neuronal cell adhesion molecule L1 (L1CAM) expressed by DTCs engages the vascular basal lamina in order to amplify integrin β1 and integrin linked kinase (ILK) signaling in DTCs. ILK promotes actin polymerization for cell spreading and subsequent activation of mechanotransduction effector transcription factors YAP and MRTF. We found that activation of YAP and MRTF coincides with DTCs ability to dislodge resident pericytes from the perivascular niche and is an essential step in the metastatic colonization regardless of dormancy state. Therefore, these results provided us a unifying molecular mechanism that governs cancer progression from metastatic seeding to overt colonization. Ongoing studies will determine how mechanotransduction and pericyte-DTC interactions can be manipulated to prevent metastatic colonization by potentiating the immune response and exposing their biophysical vulnerabilities.

Citation Format: Ekrem Emrah Er, Maria Tello-Lafoz, Jing Hu, Morgan Huse, Joan Massagué. Metastatic colonization in the perivascular niche: A mechanotransduction perspective [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 209.
Abstract 2095: AsiDNATM, a targeted therapy with no acquired resistance
Authors: Jdey Wael , Kozlac Maria , Alekseev Sergey , Johnson Danielle , Bono françoise , bhaskara Srividya , thomas frederic , Dutreix Marie
Published: August 2019

The Achilles heel of conventional and targeted anticancer treatments is intrinsic or acquired resistance following Darwinian selection, i.e. treatment toxicity place the surviving cells under intense evolutionary selective pressure to develop resistance. Here, we demonstrate that AsiDNA, the first antitumor drug with an agonist activity, can instead drive the evolution of malignant cells toward a different trajectory. Specifically, long term exposure of cancer cells to the strong alarm signal, generated by the AsiDNATM DNA repair inhibitors, did not promote resistance emergence. It induces a stable new state characterized by the down regulation of the targeted pathways that persists for months after treatments. This property is due to the original mechanism of action of AsiDNATM, which acts by over-activating a “false” signaling of DNA damage through DNA-PK and PARP enzymes, and is not observed with other DNA repair inhibitors such as the PARP inhibitors olaparib and talazoparib. Transcriptomic analysis of AsiDNATM treated independent populations derived from lung and breast cancers revealed the common evolution of independent AsiDNA-treated samples, resulting in a general down-regulation of enzymes involved in DNA repair and oncogenesis, and a specific down regulation of DNA-PK targets. Similar down regulation of DNA-PK targets was observed in xenografted tumor in animal models after three cycles of AsiDNA treatment. Chromatin analysis revealed a major change in AsiDNATM treated populations with an increased nucleosome stability that could be responsible for the epigenetic modification observed. Long term treatment with AsiDNATM induces a new “alarm down” state in the tumor cells that increase its efficacy. These results suggest that agonist drugs such as AsiDNATM could promote a state-dependent tumor cell evolution by lowering their ability to respond to damage signal as predicted by the ecological and evolutionary “smoke detector principle”.

Citation Format: Wael Jdey, Maria Kozlac, Sergey Alekseev, Danielle Johnson, françoise Bono, Srividya bhaskara, frederic thomas, Marie Dutreix. AsiDNATM, a targeted therapy with no acquired resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2095.
Abstract 2100: Resistance of gastric carcinoma cells towards c-met inhibition is mediated by compensatory HER3 upregulation involving SATB1 and PKC
Authors: Jenke Robert , Büch Thomas , Rein Miriam , Müller Stefanie , Lordick Florian , Aigner Achim M.
Published: August 2019

Introduction: In patients with gastric cancer expressing high levels of c-met, inhibitors of the receptor tyrosine kinase (RTK) c-met are explored as targeted therapeutics. Unfortunately, clinical trials have failed to improve survival so far. This might be due to compensatory stimulation of other oncogenic RTKs. Here, we highlight the role of HER3 upregulation and its specific stimulation as resistance mechanism. On the mechanistic side, we demonstrate the genome regulator special AT-rich sequence-binding protein-1 (SATB1) as a critical mediator of this HER3 upregulation, with further manipulation being executed by contrary roles of Protein kinase C (PKC) and Phosphatidylinositol 3-kinase (PI3K).

Methods: We used gastric cancer cell lines with a c-met amplification and evaluated the impact of pharmacological or siRNA-mediated c-met inhibition on cellular proliferation and survival. Moreover, we analyzed the expression of HER family receptors after inhibitor treatment. Furthermore, we used transient knockdown of SATB1 as well as inhibitors of PKC and PI3K to gain insight into signaling mechanisms.

Results: The use of c-met kinase inhibitors or RNAi-induced downregulation of c-met led to a complete disruption of cellular proliferation. Without addition of c-met inhibitors, the investigated gastric cancer cells expressed HER1, HER2, and HER3 receptors, but no HER3 ligands. After pretreatment with c-met inhibitors, HER3 expression was markedly upregulated. Treatment of gastric cancer cells with the HER3 ligand beta-heregulin, usually secreted by cancer associated fibroblasts, partially reversed the anti-proliferative effects of c-met inhibitors. The induction of HER3 was reduced after pretreating cells with SATB1 siRNA. SATB1 is a known regulator of HER receptor expression in other tumor entities. The regulatory functions of SATB1 can be further modulated by phosphorylation via PKC or PI3K. Therefore, we investigated the effect of PKC and PI3K inhibition on HER3 induction. Of note, PKC inhibition markedly reduced HER3 upregulation, whereas PI3K inhibitors even increased HER3 levels.

Conclusions: PKC and SATB1 are involved in the compensatory upregulation of HER3 upon c-met inhibition. Since this represents a critical resistance factor, interference with PKC and SATB1 signaling is a potential avenue to prevent resistance towards c-met inhibitors in gastric cancer.

Citation Format: Robert Jenke, Thomas Büch, Miriam Rein, Stefanie Müller, Florian Lordick, Achim M. Aigner. Resistance of gastric carcinoma cells towards c-met inhibition is mediated by compensatory HER3 upregulation involving SATB1 and PKC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2100.
Abstract 2103: NETs promote tumor resistance to anthracyclines
Authors: Lin Cindy , Herlihy Sarah E. , Li Marina , Deng Hui , Bernabei Luca , Gabrilovich Dmitry I. , Vogl Dan T. , Nefedova Yulia
Published: August 2019

Multiple Myeloma (MM) is an incurable blood cancer characterized by the clonal proliferation of plasma cells that accumulate in the bone marrow (BM). Resistance to chemotherapy represents one of the main challenges in the treatment of this disease. We have previously shown that neutrophils, one of the major cellular populations in the BM, protect MM cells from chemotherapies including anthracyclines; however, the mechanisms of this effect remain unknown. Thus, we set out to investigate the mechanisms by which neutrophils reduce sensitivity of tumor cells to anthracyclines. Neutrophil extracellular traps (NETs) are structures composed of chromatin and protein formed by neutrophils that are a part of an innate immune mechanism of binding and killing pathogens. Recently, NETs have been shown to form in cancer patients as well as tumor-bearing animals and have been implicated in solid tumor progression; however, their role in hematological malignancies remain poorly understood. Utilizing an in vitro culture system, we demonstrated that MM cells were able to induce NET formation by BM neutrophils. Interestingly, neutrophils isolated from the BM of patients with MM have a significantly higher ability to produce NETs in response to tumor cells as compared to BM neutrophils from donors. NET formation was accompanied by an increase in the level of extracellular DNA. Using imaging flow cytometry and confocal microscopy we demonstrated that extracellular DNA is internalized by tumor cells and localizes to the cytoplasm. This internalized DNA was able to bind to doxorubicin and other anthracyclines thereby reducing their cytotoxic effects. Significantly increased cell-free DNA levels were detected in BM aspirates from MM patients as well as in tumor-bearing mice. Targeting the extracellular DNA in vivo using the clinically available DNase, Pulmozyme, restored the sensitivity of tumor cells to doxorubicin resulting in prolonged survival of tumor-bearing animals. Here, we have identified a novel mechanism of resistance to anthracyclines that is mediated by neutrophils in the tumor microenvironment and provided evidence to support the premise that targeting this mechanism would be of significant benefit in the treatment of MM.

Citation Format: Cindy Lin, Sarah E. Herlihy, Marina Li, Hui Deng, Luca Bernabei, Dmitry I. Gabrilovich, Dan T. Vogl, Yulia Nefedova. NETs promote tumor resistance to anthracyclines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2103.
Abstract 2106: Role of organic cation transporter-1 (OCT-1) in drug resistance condition of ph+ chronic myeloid leukemia (CML)
Authors: Patel Saumya , Shah Krupa , Rawal Rakesh
Published: August 2019

A solute carrier (SLC) superfamily member, a major influx protein Organic Cation Transporter-1 (OCT-1), reported to be involved in influx of the Imatinib and other drugs in target cells. Despite the excellent responses to Imatinib and other tyrosine kinase inhibitors (TKIs) in CML, around a quarter of patients demonstrate primary resistance or suboptimal response within one year of therapy. Hence, present study mainly emphases the possible translocation mechanism of Imatinib, major TKIs and other chemotherapeutic agents that is mediated by OCT-1 transporter and OCT-1 gene expression level in progressive phases of CML. Homology based comparative modeling of OCT-1 protein, and its in-depth systemic interaction binding pattern analysis with Imatinib and other TKIs were conducted using computational modeling and molecular dynamics studies, respectively. Quantitative expression analysis of OCT-1 has also been evaluated in patients receiving Imatinib alone, hydroxyurea alone or both drug in different CML phases such as chronic, accelerated and blastic crisis phases for both in bone marrow and PBMNC samples (n=120). The interaction profile of Imatinib with OCT-1 revealed major conformational between ligand and protein interaction sites. However, generated protein-ligand complexes proceeded for molecular dynamics studies (100ns) that have confirmed the selectivity of Imatinib and other drugs towards the OCT-1 and possible translocation path of ligands in the OCT-1 cavities. In quantitative gene expression analysis, downregulation of OCT-1 expression as evident by decreased fold change values in patients with blastic crisis compared to chronic phase responsible for lower uptake of Imatinib into the cells. Hence, cells can not achieve optimum Imatinib inhibitory concentration which may be responsible for disease progression and ultimately leads to drug resistance. Thus, proposed combined computational and experimental approaches suggests OCT-1 mediated activation of bcr-abl independent mechanism, which may be potential confounder of developing Imatinib resistance in CML patients.

Citation Format: Saumya Patel, Krupa Shah, Rakesh Rawal. Role of organic cation transporter-1 (OCT-1) in drug resistance condition of ph+ chronic myeloid leukemia (CML) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2106.
Abstract 2109: A novel role for ESRP1 in regulating proliferation in therapy-resistant ER-positive breast cancer
Authors: Gökmen-Polar Yesim , Gu Yuan , Gu Xiaoping , Badve Sunil S.
Published: August 2019

Epithelial Splicing Regulatory Protein 1 (ESRP1) is a key splicing factor that plays an important role in cancer. We have previously demonstrated that ESRP1 is associated with poor prognosis and tamoxifen resistance in human ER-positive (ER+) breast tumors. Knockdown of ESRP1 decreased the tumor growth in ER+ breast cancer models resistant to endocrine therapy. In this study, we explored the upstream/downstream regulatory mechanisms of ESRP1 in tamoxifen-resistant breast cancer using ESRP1 knockdown model. Probe based-Human Transcriptome Array 2.0 (HTA; Applied Biosystems/Thermo Fisher) was performed using RNAs from control and ESRP1 knockdown cells [tamoxifen-resistant LCC2 cells (2-control) versus LCC2 cells with ESRP1 knockdown (2C3)] in ER+ breast cancer. Transcriptome profiling of ESRP1 in 2C3 knockdown model revealed that CEBP gamma, a transcription factor belonging to the CCAAT/enhancer-binding protein (C/EBP) family, was significantly decreased in ESRP1 knockdown cells (p value=2.33E-06). The expression of other related proteins C/EBP family including C/EBP alpha, C/EBP beta, and C/EBP delta that form homodimers and heterodimers with each other was also assessed. In knockdown cells, C/EBP alpha was increased (p value=0.0022), while two different C/EBP beta transcripts were decreased (p values=0.0010 and 0.03, respectively). C/EBP delta expression was not significantly altered. Using a competitive promoter-binding transcription-factor assay, we measured the transcription activity of C/EBP gamma in the absence and presence of ESRP1 promoter DNA fragment. We identified strong binding of C/EBP gamma to ESRP1 promoter region indicating that it is upstream regulator of ESRP1. CEBP transcription factor family members are important regulators of proliferation via cyclin-dependent kinases (CDKs). We further demonstrated that CDK4/CDK6 inhibitor abemaciclib decreases the expression of ESRP1 and C/EBPG levels significantly (p values= 0.0009 and 0.0019, respectively). In conclusion, for the first time, we identify that C/EBP gamma upregulates ESRP1 expression, which further regulates proliferation through control of expression of CDKs.

Citation Format: Yesim Gökmen-Polar, Yuan Gu, Xiaoping Gu, Sunil S. Badve. A novel role for ESRP1 in regulating proliferation in therapy-resistant ER-positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2109.
Abstract 2118: Collateral resistance trajectories following failure to antimitotic drugs
Authors: Aldonza Mark Borris D.
Published: August 2019

Secondary drug resistance stems from dynamic clonal evolution during the development of a prior primary resistance. This collateral type of resistance is often a characteristic of cancer recurrence. Yet, mechanisms that drive this collateral resistance and their drug-specific trajectories are still poorly understood. Using resistance selection in concert with small-scale pharmacological screens and data mining in a large pharmacogenomics database, we identified and validated unique collateral resistance trajectories that occur between chemically-different classes of drugs. One convincing case is the co-resistance between microtubule-targeting drugs and EGFR-tyrosine kinase inhibitors (EGFR-TKIs). With paclitaxel resistance as a proxy first-line drug failure model and EGFR-TKI resistance as a collateral, we find that a prior resistance can follow distinct trajectories towards collateral resistance, leading to formation of more stable resistant cell populations. These trajectories can be directed by mechanisms regulating the entry to a drug-tolerant persistent state during exposure to therapy. Collectively, our work unravels the alterations in cellular states defining collateral resistance trajectories to EGFR-TKIs following prior resistance to antimitotic drugs.

Note: This abstract was not presented at the meeting.

Citation Format: Mark Borris D. Aldonza. Collateral resistance trajectories following failure to antimitotic drugs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2118.
Abstract 2137: Aberrant nuclear-expressed SLC29A2 as a therapeutic target in hepatocellular carcinoma
Authors: Shen Roger , Jou Yuh-Shan
Published: August 2019

Hepatocellular carcinoma (HCC) is the second most prevalent causes of death in cancer worldwide, and there is lack of promising therapeutic target for patients. Here, we demonstrate that SLC29A2 (Solute Ligand Carrier Family 29 Member 2), an equilibrative nucleoside transporter, is commonly amplified and upregulated in varieties of cancers including hepatocellular carcinoma (HCC). SLC29A2 expression is increased and accumulated in nucleus during HCC progression, accompanied by interacting with phospho-STAT3, and further regulated STAT3-downstream genes to promote tumorigenic and metastatic features in HCC cell lines and preclinical orthotopic mouse model. Oncogenic properties of nuclear SLC29A2 could be suppressed by disrupting the nuclear translocation with nuclear importing mutant RanQ69L, SLC29A2 membrane anchoring mutant, and treating the inhibitor of SLC29A2. Treating inhibitor reduces nuclear SLC29A2-driven oncogenic features by reducing STAT3 phosphorylation, interrupting SLC29A2/STAT3 interaction, and nuclear translocation of SLC29A2 while SLC29A2 is amplified or upregulated in HCC cells. Combined treatment of FDA-approved late stage HCC medicine sorafenib with SLC29A2 inhibitor further suppresses tumor progression and metastasis to prolong mice survival in preclinical orthotopic model. Together, our results suggest that SLC29A2 is a theranostic target, and provide molecular insights for targeting nuclear SLC29A2.

Citation Format: Roger Shen, Yuh-Shan Jou. Aberrant nuclear-expressed SLC29A2 as a therapeutic target in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2137.