bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 3552: Metabolite profiling reveals the glutathione biosynthetic pathway as a therapeutic target in triple negative breast cancers
Authors: Beatty Alexander 
Published: August 2015

Abstract
Identifying metabolic pathway alterations that are critical to support cancer growth is a key hurdle for developing therapeutic strategies that exploit these pathways. We have applied metabolomic and pharmacological approaches to identify targetable pathways in triple negative breast cancer (TNBC). TNBC is an aggressive and genomically heterogeneous subset of breast cancer that is resistant to existing targeted therapies. To identify dysregulated metabolic pathways in TNBC, we conducted mass spectrometry-based metabolomics of TNBC and control cells. The relative levels of 155 intracellular metabolites distinguished TNBC from non-transformed breast epithelia, and revealed two metabolic subtypes within TNBC that, unexpectedly, correlate with markers of basal-like versus non-basal-like status. Distinguishing metabolites included amino acids, lipids and the cellular redox buffer glutathione. Levels of glutathione were generally lower in TNBC cell lines compared to controls, and markedly lower in the metabolic subtype containing non-basal-like TNBC. Further, these cell lines showed enhanced sensitivity to inhibition of glutathione biosynthesis, showing a dependence on glutathione production for survival. These findings demonstrate the potential of targeting the glutathione biosynthetic pathway as a therapeutic strategy in TNBC, and suggest that existing clinical biomarkers may provide a means for stratifying TNBC tumors to identify likely responders to anti-glutathione therapy.
Citation Format: Alexander Beatty. Metabolite profiling reveals the glutathione biosynthetic pathway as a therapeutic target in triple negative breast cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3552. doi:10.1158/1538-7445.AM2015-3552
Abstract 3594: P-glycoprotein attenuates Src activation and DNA repair activity via increased C-terminal Src kinase-binding protein, a negative regulator of Src, in multidrug-resistant cells
Authors: Lin Li-Fang , Wu Ming-Hsi , Su Tsann-Long , Lee Te-Chang 
Published: August 2015

Abstract
Multidrug resistance (MDR) remains a significant obstacle to the success of cancer chemotherapy. MDR is often associated with increased expression of ATP-binding cassette transporter family members, which extrude anticancer drugs out of cells. The MDR1 gene product, P-glycoprotein (P-gp) is one of the most well-known ABC transporters and expels a broad range of anticancer drugs, such as vinblastine, vincristine, doxorubicin and paclitaxel. Overexpression of P-gp in tumor tissues is thus a prognostic indicator associated with poor response to chemotherapy and poor clinical outcome. Our previous study has shown that P-gp overexpression attenuates the repair activity of DNA interstrand crosslinks (ICLs) and hence contributes the susceptibility of MDR cells to DNA ICL agents [1]. In the present study, we explored the molecular mechanisms underlying which P-gp interferes with Src-activated DNA repair activity. We first confirmed that ectopic expression of P-gp attenuates DNA ICL repair activity and becomes more susceptible to DNA ICL agents than vector control cells. Our present results showed that the C-terminal Src kinase-binding protein (Cbp), a negative regulator of Src, is significantly enhanced in MDR cells. Cbp silencing by siRNA technique apparently enhances cisplatin-induced Src activation and DNA repair activity, and hence increases the resistance of MDR cells to ICL agents. By aid of immuneprecipitation and immunofluorescence staining techniques, we demonstrated that P-gp not only interacts with Cbp and Src but also enhances the formation of inhibitory Csk-Cbp complex that reduces phosphorylation of Src activation residue Tyr416 and increases phosphorylation of Src negative regulatory Tyr527 residue. Taken together, the current results indicate that P-gp overexpression in MDR cells attenuates DNA repair activity by mediating Cbp dependent mechanism to interfere with Src activation. These results implicate that increasing the expression of Cbp is potentially a therapeutic strategy to increase the susceptibility of cancer cells to chemotherapeutic agents.
1. Lee PC, Lee HJ, Kakadiya R, Sanjiv K, Su TL, Lee TC: Multidrug-resistant cells overexpressing P-glycoprotein are susceptible to DNA crosslinking agents due to attenuated Src/nuclear EGFR cascade-activated DNA repair activity. Oncogene 2013, 32:1144-1154.
Citation Format: Li-Fang Lin, Ming-Hsi Wu, Tsann-Long Su, Te-Chang Lee. P-glycoprotein attenuates Src activation and DNA repair activity via increased C-terminal Src kinase-binding protein, a negative regulator of Src, in multidrug-resistant cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3594. doi:10.1158/1538-7445.AM2015-3594
Abstract 3607: Loss-of-function screens using haploid KBM7 and HAP1 cells to identify mechanisms of anti-cancer drug resistance
Authors: Gerhards Nora M. , Guyader Charlotte , Blomen Vincent A. , Küçükosmanoğlu Aslı , van Tellingen Olaf , Vis Daniel J. , Wessels Lodewyk F. , Brummelkamp Thijn R. , Borst Piet , Rottenberg Sven 
Published: August 2015

Abstract
The lack of biomarkers to predict anti-cancer therapy response remains a major obstacle in the treatment of various cancers. This handicap not only affects novel targeted therapies. Also for classical chemotherapeutic drugs such as DNA cross-linking agents, topoisomerase inhibitors or microtubule-targeting compounds, which are all frequently used in the clinic, we do not understand well why some patients have a major benefit of the therapy whereas others do not. A decreased intracellular drug accumulation has been proposed as one potential mechanism, but the clinical relevance of known uptake and efflux mechanisms is still controversial for various chemotherapeutic drugs. To identify novel factors that may be relevant for the intracellular concentration of drugs, we carried out loss-of-function screens using haploid KBM7 and HAP1 cells. In particular, we used the PARP inhibitor olaparib, the topoisomerase I inhibitor topotecan, platinum drugs, and the microtubule-targeting compounds docetaxel and vinorelbine to select resistant clones. We will present results from these screens and their validation, including independent cell lines and TCGA data sets.
Citation Format: Nora M. Gerhards, Charlotte Guyader, Vincent A. Blomen, Aslı Küçükosmanoğlu, Olaf van Tellingen, Daniel J. Vis, Lodewyk F. Wessels, Thijn R. Brummelkamp, Piet Borst, Sven Rottenberg. Loss-of-function screens using haploid KBM7 and HAP1 cells to identify mechanisms of anti-cancer drug resistance. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3607. doi:10.1158/1538-7445.AM2015-3607
Abstract 3609: In vitro comparison of conventional hyperthermia and electro-hyperthemia
Authors: Chi Kwan-Hwa , Wang Yu-Shan Samuel , Huang Cheng-Chung , Chang Chao-Chun , Chi Mau-Shin , Yang Kai-Lin , Tsang Yuk-Wah , Andocs Gabor 
Published: August 2015

Abstract
Purpose:
Deep heating hypertermia methods are a promising cancer treatment modalities used to enhance conventional treatment. This could be achieved through radiofrequency field en-bloc heating by Thermotron RF-8 and selective tumor heating by Oncotherm-Labehy, respectively. This is the first study to evaluate the different cytotoxic effect and action mechanism on cancer cells after mild hyperthermia (MHT) by Thermotron RF-8 or Oncothermia-Labehy.
Experimental Design:
Hepatoma HepG2 cells were used for MHT treatment (42°C for 30minute). Either by Oncotherm-Labehy or Thermotron RF-8 or water bath treatment were compared. Apoptosis evaluated 24h after MTH as measured by Annexin-V assay and cell cycle analysis. Mitochondria-targeted damage as measured by ROS production with or without Mito-TEMPO treatment and membrane-targeted damage as measured by caspase-8 expression, adhesion molecule expression, heat shock protein (HSP) release and calcium channel disturbance were evaluated and compared.
Results:
MHT resulted in similar cell cycle arrest on G2/M. Oncothermia treatment resulted in higher apoptosis rate (38.87±6.58) than RF-8 (25.13±2.26), water bath (18.77±0.35) and control (14.93±0.76). The expression of Caspase-8 is higher by oncothermia treatment, while caspase-3 and 9 levels were similar between 3 types of treatment. HSPs were upregulated by MHT, however a marked HSP release outside cell and E-cadherin overexpression on the membrane were only observed after oncothermia treatment.
Conclusion:
In this report, we found that different hyperthermia devices may induce different mechanisms on their cytotoxic effects and cell responses to heat. Oncothermia may selectively target on cell membrane before targeting on mitochondria, while RF-8 has no membrane targeting effect. These results may provide rational basis for future clinical application of hyperthermia treatment.
Citation Format: Kwan-Hwa Chi, Yu-Shan Samuel Wang, Cheng-Chung Huang, Chao-Chun Chang, Mau-Shin Chi, Kai-Lin Yang, Yuk-Wah Tsang, Gabor Andocs. In vitro comparison of conventional hyperthermia and electro-hyperthemia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3609. doi:10.1158/1538-7445.AM2015-3609
Abstract 3610: DMH4, A VEGFR2 inhibitor effectively suppresses proliferation and migration of lung cancer cells
Authors: Li Hao , Bae Chay , Gazy Nicky , Hao Jijun , Zhong Li 
Published: August 2015

Abstract
Background
Currently there is a major unmet medical need for effective therapy of the non-small cell lung cancer (NSCLC). It is well known that vascular endothelial growth factor (VEGF) signaling plays a critical role in regulating tumor angiogenesis, and bevacizumab is the only approved antiangiogenic agent for the treatment of NSCLC to date. Due to individual differences in drug response, developing novel angiogenic inhibitors is essential for NSCLC treatment. We have recently developed DMH4, a small molecule which specifically inhibits VEGF signaling by targeting VEGF receptor 2 (VEGFR2) (Hao, et al 2010). Here, we show that DMH4 can effectively suppress proliferation and migration of NSCLC cells.
Method
Briefly, NSCLC cell line H460, A549 and a lung fibroblast cell line MRC5 was treated by DMH4 at concentrations of 0.25 ug/ml, 0.5 ug/ml,1 ug/ml, 2 ug/ml, 4 ug/ml, 8 ug/ml and 16 ug/ml. MTT assay was taken out for testing cell viability at 24 hr, 48 hr and 72 hr. Meanwhile, FITC Annexin V/PI double staining was taken out to distinguish apoptosis and necrosis. Scratch assay was taken out to evaluate cell migration. Cell lysate was collected at the same time. Phospho-VEGF Receptor 2 level and Phospho-Akt level were tested through Western Blot. 43 apoptosis related protein levels were measured using human apoptosis antibody array assay.
Result
The data from MTT assay showed that DMH4 treatment decreased cell viability in a dose-depend manner. At the concentrations of 1 ug/ml, DMH4 effectively decreased viabilities of both H460 (82.1%, P&lt;0.01) and A549 (78.5%, P&lt;0.01) NSCLC cells, but had no effect on the normal lung MRC5 cells (103.6%). In addition, our study demonstrated that DMH4 promoted apoptosis in NSCLC cells, but did not show significantly effects in normal lung cells. Our further study indicated that DMH4 also suppressed NSCLC migration. Through Western Blot, phospho-VEGFR2 and phosphor-Akt levels were both detected lower in H460 and A549 than in MRC5.
Conclusion
As it can effectively suppress cell proliferation and migration in NSCLC cells but not in normal lung cells, DMH4 may be a good drug lead as a new VEGFR2 inhibitor for NSCLC treatment in the future.
Note: This abstract was not presented at the meeting.
Citation Format: Hao Li, Chay Bae, Nicky Gazy, Jijun Hao, Li Zhong. DMH4, A VEGFR2 inhibitor effectively suppresses proliferation and migration of lung cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3610. doi:10.1158/1538-7445.AM2015-3610
Abstract 3621: Deubiquitination of AXIN1 by USP9X promotes apoptosis in melanoma in response to BRAF or MEK inhibition
Authors: Potu Harish , Peterson Luke F. , Kandarpa Malathi , Fearon Eric , Talpaz Moshe , Donato Nicholas J. 
Published: August 2015

Abstract
The Wnt/β-catenin pathway is important in development, transformation and self-renewal of various tissues and tumors. In contrast, Wnt/β-catenin signaling appears to play a paradoxical role in melanoma where its activation is anti-oncogenic and a marker of good prognosis. Previous studies have shown that activation of the NRAS/BRAF/MEK pathway suppresses Wnt/β-catenin signaling and reduces apoptotic sensitivity to BRAF or MEK inhibitors in melanoma. MEK pathway activation stabilized AXIN1, a Wnt/β-catenin inhibitor, in some melanoma cell lines through a proteasome-dependent process and co-treatment with Wnt3A and BRAF/MEK kinase inhibitors resulted in a reduction of AXIN1 and full activation of apoptosis. Further, AXIN1 knockdown sensitized BRAF/MEK inhibitor insensitive cells to kinase inhibition, providing a prominent role for AXIN1 in determining melanoma cell apoptotic responsiveness and exposing a potential mechanism for improving kinase inhibitor clinical activity. While AXIN1 protein levels appear to be regulated by ubiquitination, the enzymes involved in control of its ubiquitination or deubiquitination are not fully defined. Here we show that ubiquitin-specific peptidase 9, X-linked (USP9X), a deubiquitinating enzyme whose expression is elevated in melanoma, binds and deubiquitinates AXIN1. USP9X knockdown resulted in increased ubiquitination and proteasome-mediated depletion of AXIN1 (but not AXIN2), resulting in a reduction in AXIN1 cellular half-life. USP9X knockdown elevated β-catenin response genes (&gt;2-fold) in melanoma cells treated with Wnt3A. USP9X depletion also increased apoptotic responsiveness to Wnt3A or BRAF/MEK inhibitor and overcame BRAF inhibitor resistance in A375R cells. In contrast, USP34 which was previously shown to regulate AXIN1 (and AXIN2) deubiquitination, did not alter AXIN1 levels or apoptotic responsiveness in melanoma. A previously identified small molecule USP9X inhibitor (EOAI3402143 or G9) replicated the effects of USP9X knockdown on AXIN1 depletion in vitro and in vivo, suppressed melanoma tumor growth in animals and fully blocked in vivo tumor growth when combined with BRAF kinase inhibitor. Thus, we identify USP9X as a potential therapeutic target in melanoma and established G9 as a lead compound for the development of AXIN1 depleting agents that may add to the targeted therapies already used in the treatment of melanoma.
Note: This abstract was not presented at the meeting.
Citation Format: Harish Potu, Luke F. Peterson, Malathi Kandarpa, Eric Fearon, Moshe Talpaz, Nicholas J. Donato. Deubiquitination of AXIN1 by USP9X promotes apoptosis in melanoma in response to BRAF or MEK inhibition. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3621. doi:10.1158/1538-7445.AM2015-3621
Abstract 3626: Expression of BARD1 splice variant impairs homologous recombination and can predict PARP1 inhibitor therapy in colorectal cancer
Authors: Ozden Ozkan , Bishehsari Faraz , Bauer Jessica , Baik Seung Hyua , Jung Barbara 
Published: August 2015

Abstract
Background & Aims: BRCA1 associated RING domain protein 1 (BARD1) stabilizes BRCA1 protein by forming a heterodimeric RING-RING complex. Its alterations impact function of BRCA1, disabling HR (homologous recombination) repair leading to sensitivity to PARP-1 inhibition in cancer. In colorectal cancer (CRC), we observed expression of BARD1 splice variants (SVs) and loss of full-length is associated with poor prognosis despite wild type expression of BRCA1. Here, we examined the roles of BARD1 SV and its therapeutic impact on PARP-1 inhibition, oxaliplatin and irinotecan sensitivity in CRC cell lines.
Methods: A panel of CRC cell lines was treated with PARP-1 inhibitor, ABT888, and HR proficiency assessed via RAD51 foci formation. BARD1 splice variant (SV B1/4) transcription was determined via real-time PCR, and protein expression assessed via immunoblotting. Tumorigenesis of CRC cells expressing SV B1/4 and wild type BARD1 was measured by epithelial-mesenchymal transitions (EMT), colony formation abilities, and migration assays.
Results: Caco-2 CRC cells were significantly more sensitive to PARP-1 inhibition when compared to the other CRC cell lines. This sensitivity was not associated with loss of BRCA1 or full-length BARD1 expression but rather with expression of BARD1 SV 1/4. Caco-2 showed significantly impaired HR response following PARP-1 inhibition with ABT888 and characterized by decreased RAD51 foci formation. Exogenous expression of the BARD1 SV B1/4 in SW480 cells exhibits a more transformed phenotype, decreased RAD51 foci formation, reduced BRCA1 E3 ubiquitin ligase activity, and increased sensitivity to PARP-1 inhibitor. Addition of irinotecan to ABT888 pre-treated cells created higher specificity and sensitivity with respect to killing of SV B1/4 expressing SW480 cells. Further immunofluorescence and confocal microscopy studies are underway to investigate the effect of BARD1 SV B1/4 on BRCA1 homologous recombination DNA repair function.
Conclusions: Expression of BARD1 SV might be a potential biomarker for therapeutic sensitivity to PARP-1 inhibitors in treatment of CRC.
Citation Format: Ozkan Ozden, Faraz Bishehsari, Jessica Bauer, Seung Hyua Baik, Barbara Jung. Expression of BARD1 splice variant impairs homologous recombination and can predict PARP1 inhibitor therapy in colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3626. doi:10.1158/1538-7445.AM2015-3626
Abstract 3630: Inhibition of PARP by hyperthermia or pharmacological inhibitors synergize with cisplatin and doxorubicin but not with 5-FU or paclitaxel
Authors: Schaaf Lea , Ulmer Christoph , Steurer Wolfgang , Mürdter Thomas E. , Aulitzky Walter E. , van der Kuip Heiko 
Published: August 2015

Abstract
Short-term, high-dose chemotherapy together with hyperthermia (HIPEC) is widely used for treatment of peritoneal carcinomatosis. However, it is fairly known which agents currently used for HIPEC actually act synergistically with elevated temperature. Furthermore, the molecular mechanisms behind the potentiating effects are incompletely understood. To mirror the clinical HIPEC setting we cultivated 2 ovarian and 2 colon cancer cell lines under hypoxic conditions and performed a 1-hour treatment at atmospheric oxygen levels with Cisplatin, Doxorubicin, 5FU, or Paclitaxel at either 37°C or 42°C. Cells were then evaluated for long-term survival, DNA strand break repair, poly(ADP-Ribosy)lation, and γH2AX and P-53BP1 foci formation. Importantly, we found that Cisplatin as well as Doxorubicin were potentiated by hyperthermia as revealed by a significantly reduced colony forming ability whereas high temperature had no effects together with 5FU or Paclitaxel on long-term survival. The synergistic effects on survival were due to compromised DNA strand break repair capacity and followed by a significantly enhanced number of double strand breaks. Interestingly, this was paralleled by a diminished poly(ADP-Ribosy)lation indicating a reduced activity of PARP. The role of this enzyme for the hyperthermia effects was confirmed by using clinically relevant PARP inhibitors. Combination of PARP inhibitors was synergistic with the same subset of compounds as observed with hyperthermia. Short-term treatment with PARP inhibitors mimicked the effects of elevated temperature both on survival and DNA repair capacity. Hyperthermia and PARP inhibitors also led to a comparable increase of γH2AX and P-53BP1 foci in cells treated with Doxorubicin or Cisplatin.
In conclusion our data indicate that the cytotoxic effects of only a subset of currently used chemotherapeutics can be potentiated by hyperthermia. The molecular mechanisms behind these synergistic effects are related to PARP functions in DNA repair.
Citation Format: Lea Schaaf, Christoph Ulmer, Wolfgang Steurer, Thomas E. Mürdter, Walter E. Aulitzky, Heiko van der Kuip. Inhibition of PARP by hyperthermia or pharmacological inhibitors synergize with cisplatin and doxorubicin but not with 5-FU or paclitaxel. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3630. doi:10.1158/1538-7445.AM2015-3630