bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3075: Type IIB DNA topoisomerase is downregulated by trastuzumab and doxorubicin to synergize cardiotoxicity
Authors: Jiang Jiangsong , Mohan Nishant , Endo Yukinori , Shen Yi , Wu Wen Jin
Published: August 2018

Despite heightened risk of cardiotoxicity associated with combination therapy of anthracyclines and trastuzumab in HER2-positive breast cancer patients, little research effort has been invested in exploring the molecular mechanisms of cardiotoxicity induced by this combination therapy. Using human primary cardiomyocytes as a model, we demonstrate that trastuzumab downregulates both gene and protein expressions of type IIB DNA topoisomerase/DNA topoisomerase IIB (TOP2B), a major intracellular target mediating doxorubicin-induced cardiotoxicity. This downregulation of TOP2B in turn induces DNA damage activity and DNA double strand breaks. However, unlike doxorubicin, trastuzumab alone does not induce apoptosis. Further investigation discovers that concurrent or sequential treatment of doxorubicin and trastuzumab significantly reduces protein levels of TOP2B, enhances apoptosis induced by doxorubicin, and inhibits cell growth. Furthermore, treatment of cardiomyocytes with doxorubicin and trastuzumab in either concurrent or sequential setting also enhances production of reactive oxidative and nitrative species as compared to either trastuzumab or doxorubicin treatment in cardiomyocytes. Our data reveal that doxorubicin treatment increases the cellular level of ErbB2/HER2 protein and enhances downstream signaling activity of this pathway. Consequently, this may render cardiomyocytes more sensitive to trastuzumab treatment after doxorubicin exposure. This study provides molecular basis for significantly increased cardiotoxicity in cancer patients treated with anthracyclines and trastuzumab-based combination regimens.

Citation Format: Jiangsong Jiang, Nishant Mohan, Yukinori Endo, Yi Shen, Wen Jin Wu. Type IIB DNA topoisomerase is downregulated by trastuzumab and doxorubicin to synergize cardiotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3075.
Abstract 3076: Smoking behavior weakens the protective effect of mosaic loss of chromosome Y on lung cancer
Authors: Qin Na , Wang Cheng , Ma Zijian , Chen Jiaping , Shen Hongbing
Published: August 2018

Mosaic loss of chromosome Y (mLOY) is the most commonly detectable mosaic chromosomal event in cancers, however, the underlying relationship with tumorigenesis is still unclear. We conducted a Mendelian randomization study to systematically investigate the effect of mLOY on lung cancer based on published GWASs study. We identified that genetically defined mLOY was a protective factor for lung cancer in non-smokers but not in smokers (lifelong non-smokers: OR=0.80, CI=0.69-0.93, P=4.03×10-3; ever-smokers: OR=0.96, CI=0.89-1.04, P=2.90×10-1; PHeterogeneity=3.83×10-2). A U-shaped curve between the copy-number level of chromosome Y and lung cancer risk was further fitted (P for Linearity Wald=8.81×10-10) to support that heavy mLOY caused by acquired damaging environmental factors may have different effects on lung cancer from the genetically defined mLOY, while genetically predicted mLOY was linearly associated with decreased lung cancer risk (P for Linearity Wald=0.15). Taken together, we proposed a two “sides” model: the “natural” mLOY reduced the lung cancer risk, while the effect can be abolished by aberrant loss of chromosome Y caused by environmental risk factors. Our results revealed a complex relationship between mLOY and lung cancer, and emphasized the importance of heterogeneity in the mLOY studies.

Citation Format: Na Qin, Cheng Wang, Zijian Ma, Jiaping Chen, Hongbing Shen. Smoking behavior weakens the protective effect of mosaic loss of chromosome Y on lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3076.
Abstract 308: Yeast Bax Inhibitor, BXI1, is involved in calcium homeostasis of the ER in Saccharomyces cerevisiae
Authors: Andrews Nicholas , Mello Nicholas , McDonough Liam , Alisch Joseph , Eagan David , Mullin James , Gonzalez Alfredo , Austriaco Nicanor
Published: August 2018

Yeast Bax inhibitor-1 (BXI1/YBH3) encodes a protein that belongs to the Bax Inhibitor (TMBIM) family of proteins that all contain a transmembrane BAX inhibitor motif. The crystal structure of a prokaryotic member of the family, BsYetJ, has revealed that the Bax inhibitor proteins are pH sensitive calcium leaks. In mammals, the Bax inhibitor family of proteins has cytoprotective properties that are most evident in paradigms of endoplasmic reticulum (ER) stress. Our published studies have shown that yeast Bxi1p is localized to the endoplasmic reticulum and is involved in the unfolded protein response (UPR) that is triggered by ER stress. BXI1 is thought to act via a mechanism involving altered calcium dynamics. We now show that cells lacking BXI1 accumulate higher levels of calcium in their ER as compared to their wildtype counterparts. We have also over expressed Bxi1p in E.coli and have used a fura-2 based calcium assay to show that the protein facilitates the influx of extracellular calcium into the cell. Our preliminary data with Δbxi1 Δpmr1 double mutants suggest that Bxi1p and Pmr1p, the Golgi-ER calcium pump, function in an antagonistic manner. [Our laboratory is supported by grant NIGMS R15 GM110578, awarded to N. Austriaco.]

Citation Format: Nicholas Andrews, Nicholas Mello, Liam McDonough, Joseph Alisch, David Eagan, James Mullin, Alfredo Gonzalez, Nicanor Austriaco. Yeast Bax Inhibitor, BXI1, is involved in calcium homeostasis of the ER in Saccharomyces cerevisiae [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 308.
Abstract 3082: Epidermal-specific overexpression of T-cell protein tyrosine phosphatase in mouse attenuates chemically-induced skin carcinogenesis
Authors: Kim Mihwa , Morales Liza D. , Jang Iksoon , Tsin Andrew , Kim Dae Joon
Published: August 2018

Tyrosine phosphorylation signaling, which is regulated by the counter-activities of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs), is critical in maintaining cellular homeostasis. The aberrant increase of tyrosine phosphorylation by mutation and/or overexpression of PTKs can contribute to skin carcinogenesis. While PTKs have been extensively studied in skin carcinogenesis, PTPs have not been studied due to their inactivation by environmental toxicants. Our recent studies showed that T-cell protein tyrosine phosphatase (TC-PTP; encoded by Ptpn2) deficiency in mouse epidermis significantly increased skin tumor formation, demonstrating TC-PTP deficiency predisposes mice to skin carcinogenesis. To further examine the tumor suppressive role of TC-PTP in skin carcinogenesis, we generated epidermal-specific TCPTP-overexpressing (K5HA.Ptpn2) transgenic mice. TC-PTP overexpression led to sensitization to tumor initiator 7,12-dimethylbenz[a]anthracene (DMBA)-induced apoptosis both in vivo epidermis and in vitro keratinocytes. TC-PTP overexpression in epidermis significantly reduced epidermal thickness and hyperproliferation compared to wild-type control following treatment with the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA). Furthermore, TC-PTP overexpression significantly induced epidermal differentiation following TPA treatment as evidenced by the increased expression of epidermal differentiation markers loricrin, involucrin, keratin 10, and transglutaminase 5 in comparison to control. Two-stage skin carcinogenesis analysis using a DMBA/TPA regimen clearly revealed that K5HA.Ptpn2 mice exhibited delayed tumor development and significantly reduced tumor numbers compared to control mice. Taken together, our results suggest that TC-PTP is a potential therapeutic target for the prevention of skin cancer given its ability to promote epidermal apoptosis and differentiation and inhibit epidermal proliferation.

Citation Format: Mihwa Kim, Liza D. Morales, Iksoon Jang, Andrew Tsin, Dae Joon Kim. Epidermal-specific overexpression of T-cell protein tyrosine phosphatase in mouse attenuates chemically-induced skin carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3082.
Abstract 3083: Ameliorative effect of ethanolic extract of Annona muricata against sodium arsenite-induced hepatotoxicty in Wistar rats
Authors: Adegboyega Adenike M.
Published: August 2018

Ingestion of arsenic in drinking water causes cancer at multiple tissues and there is no cure. Cancer has become a great monster to human race, as it places a significant emotional and economic burden on families and governments all over the world. Research is therefore directed at chemoprevention using medicinal herbs for the management of arsenicosis. In this study, we evaluated the in vitro antioxidant and protection offered by Annona muricata L. (AM) against sodium arsenite induced hepatotoxicity in rats. Antioxidant and radical scavenging activities of AM were compared to vitamin C and butylated hydroxytoluene (BHT). Proximate and phytochemical analyses were also carried out. Hepatoprotective study was investigated with six groups of rats that received distilled water (Control), 5.0 mg/kg bwt of NaAsO2, 250 mg/kg bwt AM, 500 mg/kg bwt AM, NaAsO2 plus 250 mg/kg AM, NaAsO2 and 500 mg/kg AM. The NaAsO2 was given once on days 7, 14 and 21, while AM was administered orally daily for 21 days. Serum transaminases and alkaline phosphatase activities were determined and liver histopathology carried out. AM contained 2.00% ash, 1.94% crude fat, 25.65% crude fibre, 2.88% protein and 58.62% carbohydrate. Phytochemical analysis indicated the presence of alkaloids, flavonoids and cardiac glycosides. The reducing power and metal chelating ability was in the order Vit C > BHT > AM, while for DPPH scavenging ability AM > Vit C > BHT. The NaAsO2 significantly (p < 0.05) increased the liver function enzymes relative to control. However, AM treatment markedly reduced the marker enzymes and restores the severe vaculation of hepatocytes in the NaAsO2 group to near normal. Our findings suggest that AM may constitute a remedy against arsenic induced hepatic injuries.

Citation Format: Adenike M. Adegboyega. Ameliorative effect of ethanolic extract of Annona muricata against sodium arsenite-induced hepatotoxicty in Wistar rats [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3083.
Abstract 3091: Functional screening of genes involved in carcinogenesis using a cDNA expression library of ovarian clear cell carcinoma cells
Authors: Miyamoto Tsutomu , Yamada Yasushi , Ida Koichi , Asaka Ryoichi , Kobara Hisanori , Ando Hirofumi , Kashima Hiroyasu , Suzuki Akihisa , Shiozawa Tanri
Published: August 2018

Background: Ovarian clear cell carcinoma (OCCC) is one of the 4 major histological types of ovarian carcinoma (OVC) and is frequently arising from ovarian endometriotic cysts. OCCC is rare in the United States and western countries, but it is more frequent in Japan and may be seen in almost 25% of OVC. OCCC commonly shows chemo-resistance which makes difficult to treat OCCC. In order to develop the new therapeutics for OCCC, genetic abnormalities that lead to the development of OCCC need to be elucidated in detail. The comprehensive analysis using next-generation sequencing has rapidly revealed the accumulation of genetic abnormalities in many cancers. However, the significance of each abnormality has not been elucidated. Therefore, functional screening using a cDNA expression library was performed in order to identify genes involved in the pathogenesis of OCCC.

Methods: The mRNA was extracted from an OCCC cell line, RMG-1, and a cDNA library was established using a retroviral vector. This cDNA library was transfected into mouse NIH3T3 cells, and then the transformed foci which formed multilayered growth were picked up and the inserted DNAs of those foci were detected by sequencing. The mRNA and protein expression and the transforming ability of the identified genes were confirmed by immunohistochemistry and focus-formation assay.

Result: Seven genes were isolated; Dishevelled 1(DVL1), beta subunit of Sec61 (SEC61B), K-specific demethylase 4A (KDM4A), chromosome 1 open reading frame 38 (C1ORF38), splicing factor 1 (SF1), ribosomal protein S2 (RPS2), and ribosomal protein S3A (RPS3A). Of these genes, RT-PCR and immunostaining revealed that the expression of SEC61B and C1ORF38 was stronger than that in other histological types of ovarian cancer. A mutational analysis of the DVL1 c-terminal region detected 3 point-mutations in RMG1 cells, whereas no mutation was found in 24 cases of OCCC. Focus formation was confirmed by the transfection of SEC61B, C1ORF38, and DVL1 into NIH3T3 cells.

Conclusion: These results suggest that SEC61B, C1ORF38, and DVL1 may be involved in the pathogenesis of OCCC.

Citation Format: Tsutomu Miyamoto, Yasushi Yamada, Koichi Ida, Ryoichi Asaka, Hisanori Kobara, Hirofumi Ando, Hiroyasu Kashima, Akihisa Suzuki, Tanri Shiozawa. Functional screening of genes involved in carcinogenesis using a cDNA expression library of ovarian clear cell carcinoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3091.
Abstract 3097: Chemo prevention effect of Withaferin A, a natural compound, on mouse models of colorectal carcinogenesis
Authors: Pal Deeksha , Chandrasekaran Balaji , Baby Becca Von , Alatassi Houda , Ankem Murali , Damodaran Chendil
Published: August 2018

Introduction: Colorectal cancer (CRC) is the most common cancer and one of the leading causes of cancer-related deaths in United States as well as worldwide. Development of sporadic CRC takes an average of 15-20 years, so establishing preventive measures are possible. We are interested in a dietary compound, Withaferin-A (WA), which possesses both chemotherapeutic and chemopreventive properties. WA's effect was studied on both colitis-mediated colon and spontaneous-intestinal carcinogenesis mouse models.

Methods: In the present study, two animal models of colon cancer were used to study the chemo- preventive effect of WA. In intestinal tumorigenesis model C57BL/6-ApcMin/+ , mice at six weeks of age were orally fed with the vehicle or WA (4mg/kg body weight of mice) for five days per week for 12-14 weeks. The other model used was AOM/DSS (Azoxymethane/dextran sulfate sodium), which induces gut inflammation and tumorigenesis. Intraperitoneal injection of AOM (8mg/kg) was followed by three cycles of DSS. WA (3mg/kg body weight of mice) was administered five times per week for 8-10 weeks. After completion of the studies, the tumor tissues were subjected to histopathological and molecular analysis. An unpaired Student's t-test was used for statistical analysis.

Results: Oral administration of WA to ApcMin/+ mice leads to a significant decrease in the number of intestinal polyps and colon tumors (colon: 42%, p=0.025), proximal: 53%, p=0.0063, middle: 27.84%, p= 0.28, distal: 32.8, p= 0.001) when compared to vehicle-treated mice. Similarly, in AOM/DSS, oral administration of WA reduced polyp multiplicity by 40% (p= 0.02) compared to vehicle-treated controls. Moreover, the treatment group of both colon cancer models showed inhibition of pro-survival signaling markers (Notch1, pAKT and NFκB) as well as a decrease in proliferative markers.

Conclusion: Our results suggest that WA effectively suppresses intestinal polyp development and colitis-mediated colon carcinogenesis, suggesting a preventive and therapeutic role in colon cancer models. These findings warrant further investigation to develop novel strategies to achieve maximum benefit of dietary agents for cancer chemoprevention.

Citation Format: Deeksha Pal, Balaji Chandrasekaran, Becca Von Baby, Houda Alatassi, Murali Ankem, Chendil Damodaran. Chemo prevention effect of Withaferin A, a natural compound, on mouse models of colorectal carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3097.
Abstract 3113: Expression of autophagy- and mitophagy-related genes in clear cell renal cell carcinoma
Authors: Simon Adrian G. , Ellinger Joerg , Tolkach Yuri , Mueller Stefan C. , Kristiansen Glen , Toma Marieta I.
Published: August 2018

Objectives: First objective of this study was to establish primary cell cultures from renal cell carcinoma (RCC). Second objective was to analyze mRNA and protein expression of PINK1, PARK2, PACRG and a-Synuclein, genes involved in cell survival, apoptosis and mitophagy.

Methods: Tumor and non-neoplastic tissue from 15 patients undergoing surgery for clear cell renal cell carcinoma (ccRCC, n=9), papillary renal cell carcinoma (pRCC, n=3) as well as three retroperitoneal metastases (two clear cell, one papillary type) were obtained. After tissue digestion and filtration malignant and non-malignant cells were cultivated in two different media in order to establish an optimized cultivation procedure. DNA and RNA were extracted and immunohistochemical analyses (IHC) and qPCR from cultivated cells were performed for VHL and CAIX to verify tumor histotype. RNA was isolated from fresh-frozen primary ccRCC samples and corresponding non-malignant tissues from 50 patients (30 male, 20 female). Expression of PINK1, PARK2, PACRG and a-synuclein was measured by qPCR in the cultivated ccRCC cell lines as well as in the patient samples.

Results: All tumor specimens were successfully cultivated to first confluence. Six out of nine ccRCC cell lines and all other tumor specimens could be passaged more than two times. Cultivated RCC cells showed protein expression matching to their tumor of origin in IHC analyses, confirming tumor identity. QPCR demonstrated VHL expression downregulated or lost in all ccRCC cell lines and CA9 highly upregulated in most cases, which is both typical for ccRCC. The mRNA expression of PINK1, PARK2 and PACRG was downregulated in ccRCC cultures as well as in the 50 patient tumors in comparison to normal tissue. A-synuclein expression was highly variable.

Conclusions: We successfully established primary cell cultures from various renal tumor entities suitable for further investigation. Loss of PACRG and PARK2 are common events in ccRCC. PACRG and PARK2 might function as tumor suppressors in ccRCC and their loss may be involved in tumor progression as reported before for other tumor entities. Further investigation of PINK1, PARK2 and PACRG might allow new therapeutic approaches.

Citation Format: Adrian G. Simon, Joerg Ellinger, Yuri Tolkach, Stefan C. Mueller, Glen Kristiansen, Marieta I. Toma. Expression of autophagy- and mitophagy-related genes in clear cell renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3113.
Abstract 312: Emodin inhibits colon cancer by modulating apoptotic and cell survival signals
Authors: Saunders Ian T. , Kapur Neeraj , Mir Hina , Singh Shailesh
Published: August 2018

Colon cancer remains a formidable health care concern and is the third most common cancer among men and women. Late diagnosis and development of resistance to chemotherapeutic regimens significantly impact overall outcome and survival. Various phytochemicals have been shown to have promising anti-cancer properties. Consequently, such natural agents are emerging as an alternative treatment modality for various cancers, including colon cancer. In this study, we have tested the effect of Emodin, an anthraquinone derivative of rhubarb, on human colon cancer cell lines. Our antibody microarray data and pathway analysis indicated that Emodin induced apoptosis in colon cancer cells by triggering both intrinsic and extrinsic apoptotic pathways. These effects of Emodin were associated with modulation of death receptor expression, changes in mitochondrial membrane integrity, and DNA degradation. Further, western blot analysis confirmed that Emodin significantly increased pro-apoptotic proteins (Bak, Bax, Bad) as well as activated caspase-3 and -8. Additionally, Emodin reduced ERK1/2, NF-κB, and STATs at transcript and protein levels, suggesting it also interferes with cell survival. Hence, the ability of Emodin to induce apoptosis and inhibit cell survival by altering molecular pathways underscore its potential as chemo-preventive as well as -therapeutic agent in combination with conventional chemotherapy.

Citation Format: Ian T. Saunders, Neeraj Kapur, Hina Mir, Shailesh Singh. Emodin inhibits colon cancer by modulating apoptotic and cell survival signals [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 312.
Abstract 314: A novel MDM2-p53 antagonist APG-115 induces p53-mediated apoptosis and enhances radiosensitivity in colorectal cancer
Authors: Yi Han-Jie , Yan Xiang-Lei , Luo Qiu-Yun , Yuan Luping , Li Baoxia , Pan Wentao , Zhang Lin , Qiu Miao-Zhen , Wang Guangfeng , Zhai Yifan , Yang Da-Jun
Published: August 2018

Background: Colorectal carcinoma is the third leading cause of cancer-related mortality in China. MDM2-p53 inhibitor APG-115 is a novel potential anticancer agent. We aim to investigate the anticancer effect and radiosensitivity enhancement of APG-115 in colorectal cancer.

Materials and methods: Human colorectal cancer cell lines (LOVO, HCT116, RKO, HT29, SW480 and SW620) were treated with the APG-115 alone or with radiation (0-8Gy). Transwell, clonogenic survival assays, CCK-8, flow cytometry, RT-qPCR, Western blot were used to assay cell invasion, cell survival, cell cycle progression, quantification of mRNA expression and DNA damage repair. In vivo, xenograft mouse models (RKO Cell line) were established to analyze the anticancer effect and radiosensitivity enhancement of APG-115.

Results: In vitro, APG-115 not only inhibited invasion and proliferation of colorectal cell lines, but also induced cell-cycle arrest in G1/S phase. Meanwhile, APG-115 increased the mRNA and protein expression of p53 downstream targets dependent on MDM2-p53 signal pathway. The combination of APG-115 and radiation caused cells to accumulate in G2/M and resulted in the accumulation of H2AX-related DNA damage, indicating an increasing of radiosensitivity. In xenograft mouse models, single therapy with either radiation or APG-115 was equivalent in delaying tumor growth, although APG-115 slightly outperforming therapy with radiation alone. Combination therapy delayed tumor growth more significantly compared with either single agent therapy. By analyzing proliferation marker Ki67 in xenograft tumor specimens, we found that the number of proliferating cells significantly decreased in tumors receiving combination treatment of APG-115 and radiation compared with tumors receiving single agent treatment. These results strongly confirmed the enhanced antitumor capacity of APG-115 when combined with radiation.

Conclusions: Our data strongly suggest that MDM2-p53 inhibitor APG-115 may serve not only as a stand-alone therapy, but also as an effective adjunct to current radiotherapeutic regimens for treating colorectal cancer dependent on MDM2-p53 axis.

Citation Format: Han-Jie Yi, Xiang-Lei Yan, Qiu-Yun Luo, Luping Yuan, Baoxia Li, Wentao Pan, Lin Zhang, Miao-Zhen Qiu, Guangfeng Wang, Yifan Zhai, Da-Jun Yang. A novel MDM2-p53 antagonist APG-115 induces p53-mediated apoptosis and enhances radiosensitivity in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 314.
Abstract 3151: Novel regulation of cancer cell migration by ABCG2-enhanced autophagy
Authors: Trivedi Kalkal Anil , Ding Rui , Scotto Kathleen W.
Published: August 2018

ABCG2 is an ABC multidrug transporter best known for its ability to efflux a wide variety of chemotherapeutic agents, resulting in tumor drug resistance. More recently, our laboratory has shown that ABCG2 plays an additional role in tumor cell survival by enhancing the rate of autophagy, a conserved, catabolic recycling process that breaks down damaged proteins and cellular organelles to form cellular building blocks (Ding et al., Autophagy, 2016).

Sporadic studies over the decades have led to somewhat conflicting reports about the impact of ABCG2 expression on migration. Likewise, autophagy can play either a pro-metastatic or anti-metastatic role depending on the context. In the present study, we confirm that ABCG2 enhances tumor cell migration in vitro, and provide novel data to suggest that this enhancement is due to the ability of ABCG2 to augment autophagy flux.

Two cell line pairs were used for these studies: the NSCLC line H460 and its drug-selected ABCG2-overexpressing subline H460/MX20, and the embryonic kidney HEK293 cells stably-transfected either with ABCG2 or an empty vector. Transwell assays were used to study in vitro migration and invasion. ABCG2-overexpressing cells exhibited a marked increase in both cell migration and invasion relative to their parental counterparts. Using gelatin zymography, we also showed that ABCG2 over-expressing cells had enhanced MMP-2 activity, consistent with increased invasion. Both siRNA-mediated knockdown of ABCG2 expression and pharmacological inhibition of ABCG2 transport reduced the migration of ABCG2-overexpressing cells. Moreover, blocking autophagy using either a pharmacological or genetic approach also inhibited migration. Further supporting the hypothesis that ABCG2-enhanced autophagy influenced tumor cell migration, wild-type (WT) and MEFs in which the autophagy essential gene ATG5 was knocked out (ATG5-/-) were transiently transfected with either an empty vector or ABCG2. The ABCG2-transfected WT MEFs showed significantly enhanced migration compared to the empty vector transfected WT MEFs. The autophagy compromised ATG5-/- MEFs, however, did not display a statistically significant difference in the migration of the ABCG2 and empty-vector transfected cells, supporting the hypothesis that ABCG2 requires functional autophagy to enhance cell migration. Taken together, our results demonstrate a novel role for ABCG2 in enhancing cell migration by augmenting autophagy flux. Studies to determine whether ABCG2-regulated autophagy enhances migration and metastasis in vivo are underway.

Citation Format: Kalkal Anil Trivedi, Rui Ding, Kathleen W. Scotto. Novel regulation of cancer cell migration by ABCG2-enhanced autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3151.
Abstract 3152: RhoA-myosinII axis protects circulating tumor cells from fluid shear stress-induced damage
Authors: Moose Devon L. , Krog Ben L. , Burke Gretchen , Zhao Lei , Rhodes Lillian , Henry Michael D.
Published: August 2018

Circulating tumor cells (CTCs) are exposed to hemodynamic forces, which have long been thought to be mechanically destructive to CTCs. However, recent studies show that cancer cell lines from diverse histologies exhibit resistance to brief (millisecond) pulses of high-level (750-6400 dyn/cm2) fluid shear stress (FSS), whereas nontransformed epithelial cells are sensitive to this mechanical insult (PMID: 23226552, 26447202). Moreover, exposure of cancer cells to FSS results in cortical stiffening (PMID: 25908902). Herein, we elucidate the mechanism of FSS resistance in cancer cells, and extend these findings to experimental models of CTCs. We show that although some cancer cell lines exhibit elevated levels of membrane repair relative to nontransformed counterparts, intrinsic resistance to plasma membrane damage is a more consistent feature distinguishing cancer cells. FSS resistance is detectable in cancer cells acutely isolated from primary mouse TP53/PTEN mutant prostate tumors, not just a feature of cultured cancer cell lines. Our findings indicate that cancer cells respond to FSS by activation of RhoA-myosinII contractility, which protects them from nanometer-scale damage to the plasma membrane. Moreover, we present evidence that the RhoA myosinII axis protects CTCs from mechanical damage in animal models. Treatment of PC-3 cancer cells with a nontoxic dose of the myosin II inhibitor blebbistatin (20μM; 3h) reduced the number of intact cells arrested in the lung microvasculature immediately following tail vein injection. Additionally, treatment of mice bearing orthotopically implanted, metastatic PC-3 derived prostate tumors with blebbistatin (2.5mg/kg; 3h) acutely reduced steady-state CTC levels by approximately 10-fold. Taken together, our data indicate that viable CTCs actively resist destruction by hemodynamic forces and are likely to be more mechanically robust than is commonly thought.

Citation Format: Devon L. Moose, Ben L. Krog, Gretchen Burke, Lei Zhao, Lillian Rhodes, Michael D. Henry. RhoA-myosinII axis protects circulating tumor cells from fluid shear stress-induced damage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3152.
Abstract 3179: TORC1/2 inhibition sensitizes MYC-driven medulloblastoma cells to carboplatin chemotherapy
Authors: Maynard Rachael E.
Published: August 2018

Medulloblastoma is the most common malignant pediatric brain tumor. Tumors having high levels of c-MYC have the worst clinical prognosis, with only a minority of patients surviving. To address this unmet clinical need, we generated a human neural stem cell model of high medulloblastoma that recapitulated the most aggressive subtype phenotypically and by mRNA expression profiling. We performed an in silico analysis of these cells, which predicted that mTOR inhibitors would be potential therapeutic agents. The dual TORC1/2 inhibitor TAK228 (also known as MLN128 and INK128) is orally bioavailable and penetrates the brain. TAK228 is currently in early clinical trials for adults with glioblastoma. We hypothesized that TAK228 would have activity against MYC-driven medulloblastoma. We tested this hypothesis using the MYC amplified medulloblastoma cell lines D425 and D283 as well as our human neural stem cell models. We determined that TAK228 was effective in inhibiting both mTORC1/2 as measured by western blots showing decreased p-S6 and p-AKT473 expression. P-S6 expression is decreased by 90% and p-AKT expression is decreased by 70% in D425 cell lines treated with 20nM TAK228. We found that treatment with TAK228 decreases cell growth in D425 and D283 high-MYC medulloblatoma cell lines at concentrations of 20nM (D425 p<0.005 vs vehicle, D283 p<0.0005 vs vehicle). We also found that TAK228 induces apoptosis as measured by cleaved caspase 3 staining and an increased expression of cleaved PARP (D425 p<0.05 vs vehicle, D283 p<0.0005 vs vehicle). Because mTOR inhibition can suppress glutathione production, and glutathione is required to detoxify platinum containing chemotherapy, we hypothesized that TAK228 would cooperate with carboplatin, which is part of the current standard treatment for high-risk medulloblastoma. TAK228 in combination with carboplatin inhibits cell growth as measured by MTS assay (D425 p<0.05 vs vehicle, D283 p<0.05 vs vehicle) and induces apoptosis as measured by cleaved PARP expression. Combination therapy of TAK228 and carboplatin treatment leads to a 7-fold increase in cleaved PARP compared to cells treated with the vehicle. In vivo testing in orthotopic xenografts is currently underway to determine the survival benefit of TAK228 in combination with carboplatin. TAK228 is effective at inhibiting growth and inducing apoptosis in high-MYC medulloblastoma cell lines and shows strong combinatorial efficacy with carboplatin.

Citation Format: Rachael E. Maynard. TORC1/2 inhibition sensitizes MYC-driven medulloblastoma cells to carboplatin chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3179.
Abstract 3184: A secondary mutation in BRAF confers resistance to RAF inhibition in a BRAF V600E-mutant brain tumor
Authors: Wang Jiawan , Yao Zhan , Jonsson Philip , Allen Amy , Qin Alice Can Ran , Uddin Sharmeen , Dunkel Ira J. , Petriccione Mary , Manova Katia , Haque Sofia , Rosenblum Marc , Pisapia David J. , Rosen Neal , Taylor Barry S. , Pratilas Christine A.
Published: August 2018

BRAF V600E hyperactivates ERK and signals as an RAF inhibitor-sensitive monomer. While RAF inhibitors can produce impressive clinical responses in patients with mutant BRAF tumors, the mechanisms of resistance to these drugs are incompletely characterized. Here, we report a complete response followed by clinical progression in a patient with a BRAF V600E-mutant brain tumor treated with dabrafenib. Whole-exome sequencing revealed a secondary BRAF L514V mutation at progression that was not present in the pretreatment tumor. Expressing BRAF V600E L514V induces ERK signaling, promotes RAF dimer formation, and is sufficient to confer resistance to dabrafenib. A novel class of RAF dimer inhibitors and an ERK inhibitor are effective against BRAF L514V-mediated resistance. Collectively, our results validate a novel biochemical mechanism of RAF inhibitor resistance mediated by a secondary mutation, emphasizing that like driver mutations in cancer, the spectrum of mutations that drive resistance to targeted therapy are heterogeneous and perhaps emerge with a lineage-specific prevalence.

Citation Format: Jiawan Wang, Zhan Yao, Philip Jonsson, Amy Allen, Alice Can Ran Qin, Sharmeen Uddin, Ira J. Dunkel, Mary Petriccione, Katia Manova, Sofia Haque, Marc Rosenblum, David J. Pisapia, Neal Rosen, Barry S. Taylor, Christine A. Pratilas. A secondary mutation in BRAF confers resistance to RAF inhibition in a BRAF V600E-mutant brain tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3184.
Abstract 3189: Targeting NPM1 for controlling growth of Ewing sarcoma
Authors: Traver Geri , Sekhar Konjeti R. , Renthala Narsimha R. , Crooks Peter A. , Ofori Maxwell , Freeman Michael L.
Published: August 2018

Ewing sarcoma is a rare cancer found in children and young adults. Long term survival rates are approximately 70% for patients who present without clinically overt metastases. However, 5 year survival is less than 20% for patients with recurrent tumors or metastasis. Thus, there is a need to improve local tumor control and to treat metastatic disease. Eighty five percent of these cancers are driven by the reciprocal chromosomal translocation t (11;22) (q24;q12), a consequence of a fusion between the 5' portion of Ewing sarcoma breakpoint region 1 on EWSR1 (chromosome 22) and the 3' portion of Friend leukemia virus integration site 1 on FLI1 (chromosome 11). Nucleophosmin1 (NPM1) is a chaperone protein involved in many cellular functions, including DNA repair. NPM1 has been shown to be a novel prognostic biomarker for patients with localized Ewing's sarcoma. Overall survival is significantly lower for patients whose tumors express high levels of NPM1. Besides promoting repair of DNA double strand breaks NPM1 directly interacts with and induces c-Myc-induced hyperproliferation and transformation. Consistent with this knowledge is the observation that relapsed Ewing's patients exhibit high levels of c-Myc expression compared to disease-free patients. Therefore, we wanted to ascertain whether NPM1 represented a molecular target for controlling growth of Ewing's sarcoma. CRISPR/Cas9-mediated targeting of NPM1 exons 3 and 4, as well as lentivirus-mediated shRNA targeting of NPM1 mRNA revealed that targeting of NPM1 expression reduced survival (colony formation) of TC32 and A673 cells (P<0.05). NPM shRNA also reduced TC32 sphere formation under non-adherent conditions. YTR107 and NSC348884 are small molecule inhibitors of NPM1 oligomerization, which is required for NPM1 activity. Both drugs reduced survival of TC32 and A673 Ewing's sarcoma cells in a dose-dependent fashion (P<0.05). We interpret these data to indicate that NPM1 represents a potential molecular target for controlling growth of Ewing's sarcoma. Supported in part by RO1CA140409.

Citation Format: Geri Traver, Konjeti R. Sekhar, Narsimha R. Renthala, Peter A. Crooks, Maxwell Ofori, Michael L. Freeman. Targeting NPM1 for controlling growth of Ewing sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3189.
Abstract 32: BCL11A is necessary for the expression of extracellular matrix genes and metastatic progression of triple-negative breast cancer
Authors: Seachrist Darcie D. , Ingles Natasha N. , Hannigan Molly M. , Licatalosi Donny D. , Keri Ruth A.
Published: August 2018

Cancer stem cells (CSC) contribute to the high incidence of metastatic recurrence in triple-negative breast cancer (TNBC) and elucidating the mechanisms controlling CSC properties should provide novel targets for therapeutic development that improves patient outcomes. The transcription factor BCL11A is highly differentially expressed in TNBC versus all other subtypes and controls breast CSC phenotypes such as marker expression and tumor initiation. However, the genes that BCL11A targets to control CSC biology and whether BCL11A promotes metastatic progression are unknown. To address these questions, we assessed the impact of transiently silencing the expression of BCL11A in TNBC cells using siRNA transfections. Reducing BCL11A expression did not impact TNBC cell viability or in vitro migratory capacity. However, silencing BCL11A significantly decreased invasion of TNBC cell lines, in vitro. Furthermore, stable shRNA-mediated silencing of BCL11A in the highly metastatic MDA-MB-231 cell line reduced metastatic outgrowth when xenografted into immunocompromised mice, suggesting that BCL11A is critical for metastatic progression of TNBC. To identify the BCL11A-regulated transcriptome in TNBC, we performed RNA-seq analysis of cells transiently transfected with non-targeting or BCL11A-targeted siRNAs in the MDA-MB-231 cell line. Consistent with the impact of BCL11A on invasion, numerous genes involved in adhesion and extracellular matrix were reduced with BCL11A silencing. The gene encoding the matrix metalloproteinase, MMP1, was the most significantly differentially expressed gene, with a 10-fold decrease in RNA expression following BCL11A suppression. We confirmed this down-regulation by both qRT-PCR and western blots of independent samples, as well as in the HCC1143 TNBC cell line. Current studies are assessing the functional impact of MMP1 regulation by BCL11A on invasion and metastatic progression of TNBC.

Citation Format: Darcie D. Seachrist, Natasha N. Ingles, Molly M. Hannigan, Donny D. Licatalosi, Ruth A. Keri. BCL11A is necessary for the expression of extracellular matrix genes and metastatic progression of triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 32.
Abstract 3205: Histone tyrosine phosphorylation determines glioblastoma cell survival
Authors: Hossain Mohammad Belayat , Shifat Rehnuma , Kim Debora K. , Rivera-Molina Yiesel , Martinez Francisco Puerta , Jiang Hong , Nguyen Teresa , Johnson David G. , Bedford Mark T. , Hung Mien-Chie , Sulman Erik P. , Lang Frederick , Sawaya Raymond , Fueyo Juan , Gomez-Manzano Candelaria
Published: August 2018

Histone modification is crucial for cell signaling pathways and regulates predominantly chromatin functions related with DNA damage response (DDR) that lead cancer cells to survive upon different therapies. Receptor tyrosine kinases (RTKs) have been extensively studied in cancer progression and DDR and, recently, several reports described the role of RTKs in histone tyrosine modification. We have been focusing on the role of the receptor tyrosine kinase, TIE2, in gliomas. Our study identified the expression of TIE2 in human surgical glioma specimens in relation to malignancy, specifically in brain tumor stem cells. We have revealed that the unexpected membrane-to-nuclear trafficking of TIE2 is related with radioresistance of brain tumor stem cells, functioning as a genotoxic stress sensor to activate DNA repair machinery. Interestingly, TIE2 binds, upon IR stress, to DNA/protein complexes and phosphorylates several core histones. The tandem mass spectrum of H4 and H2B demonstrates that TIE2 directly phosphorylates not previously described H4pY51 and H2BY40 respectively, which reinvigorates TIE2's role in histone code modification. We screened for pY-readers using a SH2 domain array and found that H4pY51 and H2pY40 modifications are read by the proto-oncogenes ABL1 and CRK, respectively. Our data also showed that TIE2/H4pY54/ABL1 complex binds to DNA repair proteins, activating an NHEJ DNA repair mechanism. We summarize that upon IR stress TIE2 localizes to the nucleus where it is involved in key cellular functions by directly phosphorylating core histones, and recruiting SH2 domain proteins to the DNA damage sites, complexing to the DNA repair machinery, which in turns results in radioresistance. Our data highlight the role of epigenetics in modulating the DNA damage response of glioma radiation therapy and open new avenues to find novel targetable pathways for treatment of patients with glioblastomas.

Citation Format: Mohammad Belayat Hossain, Rehnuma Shifat, Debora K. Kim, Yiesel Rivera-Molina, Francisco Puerta Martinez, Hong Jiang, Teresa Nguyen, David G. Johnson, Mark T. Bedford, Mien-Chie Hung, Erik P. Sulman, Frederick Lang, Raymond Sawaya, Juan Fueyo, Candelaria Gomez-Manzano. Histone tyrosine phosphorylation determines glioblastoma cell survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3205.
Abstract 322: High EMSY expression defines a BRCA-like subgroup of high-grade serous ovarian carcinoma with superior survival and platinum sensitivity
Authors: Hollis Robert L. , Churchman Michael , Rye Tzyvia , McCavigan Andrena M. , Knight Laura A. , Kennedy Richard , Herrington C. Simon , Gourley Charlie
Published: August 2018

EMSY, encoding a BRCA2-binding protein, is reportedly amplified in 6-18% of high grade serous ovarian carcinomas (HGSOCs). As a negative regulator of BRCA2, HGSOCs with EMSY overexpression may mimic BRCA-mutant patients, who experience superior clinical outcome and hypersensitivity to platinum chemotherapy and PARP inhibition by virtue of homologous recombination deficiency (HRD).

Here we investigate the impact of EMSY expression, extracted from local and publicly available transcriptomic data, on the outcome and platinum sensitivity of HGSOCs. Platinum response data were collected from the Edinburgh Ovarian Cancer Database. Overall survival (OS) and progression-free survival (PFS) differences were assessed using multivariate cox regression accounting for age, stage at diagnosis and debulking status.

Within the Edinburgh cohort, high EMSY expression was associated with superior OS and PFS (table 1). Datasets from the MRC ICON7 trial control arm, Tothill et al, Mateescu et al, Pils et al, and TCGA cohorts demonstrated similar benefit for high-EMSY patients. Within the Edinburgh cohort, high-EMSY patients displayed significantly superior complete response (CR) rate to platinum at second (radio CR 44.4% vs 12.5%, P = 0.035; CA125 CR 88.0% vs 55.0%, P = 0.002) and third exposure (radio CR 50.0% vs 5.9%, P = 0.080; CA125 CR 53.3% vs 21.3%, P = 0.021), with prolonged time to progression (median 127 vs 83.5 days from second platinum, P = 0.084; median 151.5 vs 60.5 days from third platinum, P = 0.004). Within high-risk (advanced stage suboptimally debulked) HGSOCs, more high-EMSY patients remained recurrence-free 5 and 10 years from diagnosis (17.6% vs 2.7%, P = 0.031; 12.5% vs 0.9%, P = 0.041).

Together these data demonstrate a subgroup of HGSOCs defined by high EMSY expression experience superior clinical outcome and platinum sensitivity, consistent with HRD. This subgroup may therefore represent HGSOCs that are also sensitive to PARP inhibition.

DatasetEventMulti HR95% CIPEdinburghOS0.590.39 – 0.900.013PFS0.600.38 – 0.930.022MRC ICON7 control armOS0.210.07 – 0.680.009Tothill (primary tumour masses)OS0.280.09 – 0.900.032MateescuOS0.430.18 – 0.990.048PilsOS0.270.08 – 0.870.028TCGA advanced stage patientsPFS0.690.45 – 1.050.081

Citation Format: Robert L. Hollis, Michael Churchman, Tzyvia Rye, Andrena M. McCavigan, Laura A. Knight, Richard Kennedy, C. Simon Herrington, Charlie Gourley. High EMSY expression defines a BRCA-like subgroup of high-grade serous ovarian carcinoma with superior survival and platinum sensitivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 322.
Abstract 323: DNA damage response (DDR)-targeting strategy by targeting WEE1 and or ATM/ATR works in biliary tract cancer
Authors: Nam Ah Rong , Park Ji Eun , Bang Ju-Hee , Jin Mei Hua , Bang Yung-Jue , Oh Do-Youn
Published: August 2018

Background: Currently, targeting DNA damage response (DDR) is one strategy for new cancer drug development. DDR pathway involves DNA damage repair, cell cycle progression, apoptosis, and regulate the immune system. Biliary tract cancer (BTC) has a poor prognosis with a huge unmet medical need. In BTC, DNA repair pathway, which includes BAP1, MSH6, BRCA1, ATM, MLH1, and MSH2, is altered in about 20 % of cases. TP53 module is observed in 33.9% of cases (Nat Genet 2015). The purpose of this study is to evaluate DNA damage response (DDR)-targeting strategy in BTC.

Methods: Using 10 kinds of BTC cell lines (SNU245, SNU308, SNU478, SNU869, SNU1079, SNU1196, HuCCT-1, TFK-1, SNU2670, and SNU2773). AZD1775 (Wee1 inhibitor), AZD6738 (ATR inhibitor) and AZD0156 (ATM inhibitor) were tested.

Results: Among 10 cell lines, SNU308 and HuCCT1 were very sensitive to AZD1775, and SNU2670 and SNU2773 were relatively resistant to AZD1775. AZD1775 blocked phosphorylation of CDK1 (Y15) and CDK2 (Y15) in sensitive cells and but increased rH2AX in all cells. AZD1775 significantly increased apoptosis (cleavage of PARP and caspase-7) and G2/M arrest. Interestingly, Wee1 inhibitor increased pATR and pATM levels in resistant cells. AZD1775 in combination with AZD6738 or AZD0156 showed more potent antitumor effect than monotherapy of each drug.

Conclusion: Inhibition of Wee1 has an antitumor effect in some BTC cells. In combination with ATM/ATR inhibitors, the resistance to Wee1 inhibition could be overcome. Taken together, this study supports the further clinical development of DDR-targeting strategy in BTC as monotherapy or in combination.

Citation Format: Ah Rong Nam, Ji Eun Park, Ju-Hee Bang, Mei Hua Jin, Yung-Jue Bang, Do-Youn Oh. DNA damage response (DDR)-targeting strategy by targeting WEE1 and or ATM/ATR works in biliary tract cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 323.