bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 566: Withaferin A causes autophagy in normal as well as cancerous human breast cells
Authors: Hahm Eun-Ryeong , Singh Shivendra V. 
Published: August 2012

Abstract
Withaferin A (WA), a promising anticancer constituent of traditional Indian (Ayurvedic) medicinal plant Withania somnifera, inhibits growth of MDA-MB-231 (estrogen-independent) and MCF-7 (estrogen-responsive) human breast cancer cells in culture and MDA-MB-231 xenografts in vivo in association with apoptosis induction. We have shown recently that WA-induced apoptosis in human breast cancer cells is initiated by reactive oxygen species (ROS) resulting from inhibition of mitochondrial respiration. Because ROS are frequently implicated in induction of autophagy, which is an evolutionary conserved process for bulk-degradation of macromolecules including organelles, we raised the question of whether WA treatment causes autophagy. In the present study, we have addressed this question using MDA-MB-231 and MCF-7 human breast cancer cells, a spontaneously immortalized and non-tumorigenic normal human mammary epithelial cell line (MCF-10A), and MDA-MB-231 xenografts from control and WA-treated mice. WA treatment resulted in autophagy induction in cancerous (MCF-7 and MDA-MB-231) as well as normal mammary epithelial cells (MCF-10A) as judged by transmission electron microscopy, cleavage of microtubule-associated protein 1 light chain 3 (LC3), formation of acidic vesicular organelles, and punctate pattern of LC3 localization. Immunohistochemical analysis revealed markedly higher expression of LC3 in MDA-MB-231 xenografts from female athymic mice administered i.p. with 4 mg/kg WA compared with control. Autophagy is a protective mechanism against apoptosis by several agents. Interestingly, inhibition of WA-induced autophagy either by a pharmacological agent (3-methyladenine) or siRNA knockdown of critical autophagy regulating proteins ATG5 or Beclin1 did not have any meaningful impact on growth inhibition or apoptotic cell death resulting from WA exposure in MDA-MB-231 or MCF-7 cells. Collectively, these results indicate that WA induces autophagy in breast cancer cells regardless of estrogen receptor expression and this response is not unique to cancerous breast cells. In addition, unlike many other agents, autophagy induction by WA has no influence on its ability to inhibit cell growth or cause apoptosis at least in breast cancer cells. This investigation was supported by US PHS grant CA142604 awarded by the National Cancer Institute.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 566. doi:1538-7445.AM2012-566
Abstract 5666: DNA repair defects enhance tumor cell sensitivity to sapacitabine
Authors: Frame Sheelagh , Armour Sian , Zheleva Daniella I. , Green Simon R. , Blake David G. 
Published: August 2012

Abstract
Sapacitabine, a novel, orally available, pro-drug of CNDAC (2′-C-cyano-2′-deoxy-1-β-D-arabino-pentofuranosylcytosine), is currently being evaluated in SEAMLESS, a pivotal Phase 3 trial in elderly patients with AML, and Phase 2 trials in AML, MDS, NSCLC, and CLL/SLL. CNDAC acts by a unique DNA-damaging mechanism. After CNDAC is incorporated into DNA, single-strand DNA breaks are generated via a β-elimination reaction. If unrepaired, these are subsequently converted to double-strand breaks during further replication. These DNA breaks can also activate the G2 checkpoint, leading to cell cycle arrest in G2. Parallel approaches have been utilized to identify further rational therapeutic development strategies for sapacitabine, particularly focusing on solid tumors. These approaches include synthetic lethality screening using focused siRNA libraries in CNDAC-treated cells, and screening for agents that could synergistically induce cell death when administered in combination with CNDAC. These have demonstrated that depletion or inhibition of components of the homologous recombination DNA repair (HRR) pathway (including ATM, BRCA1/2, Rad 51 and XRCC3) or disruption of the G2 checkpoint greatly sensitizes tumor cell lines to CNDAC-induced cell death. For example, cell lines in which BRCA1 or BRCA2 has been depleted through siRNA are significantly more sensitive to the compound than control cells. Moreover, inhibitors of the ATM or Chk1 kinases also sensitize cells to CNDAC, the latter through abrogation of the G2 checkpoint. These complementary approaches have underscored the potential clinical utility of sapacitabine in patients carrying homologous recombination DNA repair deficient (HRD) tumors, and have also highlighted promising combination strategies. Drug combination screening has also assessed the potential for combining sapacitabine with other agents active in HRD tumors, including platins and PARP inhibitors. Ongoing work is extending these findings to several solid tumor indications, including breast, ovarian and non-small cell lung cancers. Correlation of HRR status and CNDAC sensitivity will be reported for a panel encompassing cell lines derived from each of these target indications, in order to guide future clinical development of sapacitabine in solid tumors, and to aid development of biomarkers to identify suitable patients.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5666. doi:1538-7445.AM2012-5666
Abstract 567: Withaferin A-induced apoptosis in human breast cancer cells is associated with suppression of inhibitor of apoptosis family protein expression
Authors: Lee Joomin , Hahm Eun-Ryeong , Singh Shivendra V. 
Published: August 2012

Abstract
Withaferin A (WA) is a promising cancer chemopreventive constituent of a traditional Indian medicine (Ayurvedic medicine) plant, Withania somnifera. This plant has been safely used for centuries in India for the treatment of different ailments. We have shown previously that WA treatment suppresses the growth of cultured (MCF-7 and MDA-MB-231) as well as xenografted (MDA-MB-231) human breast cancer cells by causing apoptosis but the mechanism of cell death is not fully understood. The inhibitor of apoptosis (IAP) family proteins, including X-linked Inhibitor of Apoptosis (XIAP), Survivin, cIAP1, and cIAP2, have emerged as critical regulators of apoptosis by functioning as inhibitors of caspases. The IAP family proteins are also implicated in adaptive response to cellular stress and immune responses. The present study was designed to determine the role of IAP family proteins in execution of WA-induced apoptosis. Exposure of MCF-7 and MDA-MB-231 cells to WA resulted in downregulation of XIAP, Survivin, cIAP1, and cIAP2 proteins as judged by western blotting and immunocytochemical analysis. The WA-mediated downregulation of cIAP2 and Survivin proteins was attributable to their transcriptional repression. On the other hand, WA treatment promoted proteasomal degradation of XIAP and cIAP1 proteins. Overexpression of XIAP, Survivin, and cIAP2 in MCF-7 and MDA-MB-231 cells conferred significant resistance towards WA-induced apoptosis. Moreover, WA-mediated inhibition of MDA-MB-231 xenograft growth in vivo was accompanied by statistically significant decrease in Survivin protein expression in the tumor. The WA treatment caused activation of intrinsic and extrinsic caspase pathways. Furthermore, the WA-induced apoptosis was significantly attenuated in the presence of caspase inhibitors. In conclusion, the present study indicates that WA-induced apoptosis in human breast cancer cells is mediated by downregulation of IAP family proteins. This investigation was supported by the US PHS grant CA142604 awarded by the National Cancer Institute.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 567. doi:1538-7445.AM2012-567
Abstract 5672: Mibefradil increases paclitaxel's effect on MCF-7 cell proliferation in vitro and in vivo
Authors: Pottle Jonathan , Sun Chengrong , Gray Lloyd , Li Ming 
Published: August 2012

Abstract
T-type Ca2+ channel mediated Ca2+ influx is important for tumor cell proliferation. In order to understand the role of this influx in tumor cell cycling, we conducted experiments to block T-type calcium channels in MCF7 breast cancer cells using pharmacological inhibitors, mibefradil or its more T-type calcium channel specific derivative NNC-55-0396, and examined the effects of this blockade on the passage through the cell cycle of MCF7 cells and whether T-type calcium channel inhibition can be used in conjunction with paclitaxel chemotherapy to increase the efficacy of the chemotherapy. Flow cytometry shows that blocking T-type calcium channels with the specific inhibitor NNC-55-0396 resulted in an increase in MCF7 cells in the G1 phase and a decrease in cells in the S phase of the cell cycle. Treatment with paclitaxel for 72 hours in vitro yielded lower MCF7 cell numbers than treatment with NNC-55-0396, as measured by a cell proliferation assay. However, a treatment regimen alternating NNC-55-0396 with paclitaxel over 72 hours was found to reduce MCF7 cell number to a larger degree than either agent alone for the same time period. For in vivo modeling, MCF7 xenografts were implanted in the mammary fat pads of nude mice, with tumor size monitored via caliper measurements. Similar to the in vitro findings, a treatment regiment that alternated paclitaxel chemotherapy with the calcium channel inhibitor mibefradil reduced tumor size to a larger degree than either agent alone, though that difference did not rise to a statistically significant level. These results indicate that blocking T-type calcium channels halts proliferating MCF7 cells at the G1/S checkpoint, and that this phenomenon may lead to an increased sensitivity to paclitaxel chemotherapy.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5672. doi:1538-7445.AM2012-5672
Abstract 5674: Effect of clofarabine on apoptosis and DNA synthesis in human breast cancer
Authors: Wang Xin , Albertioni Freidoun 
Published: August 2012

Abstract
As a second-generation nucleoside analogue, clofarabine, is employed primarily for the treatment of paediatric patients with relapsed or refractory acute lymphoblastic leukaemia after at least two prior regimens, but its application toward the solid tumors attracts more and more attention recently. In this study, the effect of clofarabine was investigated in several breast cancer cell lines and compared to a normal cell line (hTERT RPE-1). Upon treatment with 0.1 or 0.2μM clofarabine for 48 hrs, inhibition of cell growth (S-phase arrest) was investigated in both breast cancer and normal cell lines. And we observed that the induction of apoptosis was obvious in the all breast cancer cells but not in the normal cells. More than 40% breast cancer cells entered apoptotic or/and necrotic process after they were treated to 0.2μM clofarabine for 48 hrs. This was associated with an increase in dCK activity in malignant cells between 2.2 and 4.7 folds but only 1.2-fold in hTERT RPE-1 cells. Upon treatment with clofarabine, the cleaved-caspase 3 was observed and the level of anti-apoptotic protein (Bcl-2 and Bcl-xL) down-regulated significantly in the breast cancer cell lines, but not in the hTERT RPE-1 cells. In addition, the sensitivity of all breast cancer cells to the toxicity of clofarabine was attenuated significantly by down-regulation of dCK with siRNA. These results showed that as a single-agent and combination regim clofarabine is worth to be explored in solid tumor.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5674. doi:1538-7445.AM2012-5674
Abstract 5675: Potential use of proteosome pathway inhibitor (bortezomib) in combination with anthracyclines to treat multiple myeloma and pancreatic cancer
Authors: Frank Nicole , Kumbulla Suela , Jain Aditi , Lai Jim , Olson Richard , Cusack Barry , Bhushan Alok 
Published: August 2012

Abstract
Anthracyclines are widely used to treat cancers, but may also cause a cumulative dose-related cardiotoxicity. One possible mechanism of cardiotoxicity relates to effects on the cardiomyocyte proteasomal/ubiquitin system (UPS), the major protein recycling system in the cell. The goal of the research is to determine the impact of anthracyclines on the UPS and modulate cardiotoxicity by using other drugs in combination. Rats were treated chronically with a clinically relevant dose of daunorubicin (DNR) or the vehicle (controls) over 9 weeks. Another group received DNR pretreated with ICRF (dexrazoxane; a known protectant against anthracycline cardiotoxicity). The hearts were harvested one week later and analyzed. Isometric atrial preparations from rats treated with DNR showed decreased contractility compared to those pretreated with ICRF or with DNR vehicle only. Ubiquitin ligase atrogin-1 has been associated with muscle atrophy and cancer cachexia. In western blot analysis of common E3 ligases in left ventricle samples from rats treated with DNR, Atrogin-1 showed a significant reduction (P&lt;0.05) compared to animals pretreated with ICRF or DNR vehicle. This suggests that chronic anthracycline cardiotoxicity is accompanied by ubiquitin function. Bortezomib, a proteasomal inhibitor, is approved for treatment of multiple myeloma (MM) and is being investigated for treatment of pancreatic cancer with other drugs. To understand the antineoplastic interaction of a proteosome inhibitor (bortezomib) with an anthracycline (doxorubicin), we performed dose-response assays using MM and pancreatic cancer cell lines. Our studies indicate that, compared to bortezomib alone, 0.05 µM of doxorubicin in combination with bortezomib, enhanced cytotoxicity of bortezomib in the two cell lines. Thus, bortezomib and anthracycline combination therapy may provide enhanced tumoricidal activity for MM and pancreatic cancer compared to bortezomib alone. It is important to understand the mechanisms of the effect of bortezomib and anthracyclines on ubiquitin-proteasome pathway. (Supported by a St. Luke's Health System Mountain States Tumor and Medical Research Institute grant)
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5675. doi:1538-7445.AM2012-5675
Abstract 5676: Effects of resveratrol on paclitaxel-sensitive and -resistant triple negative breast cancer cells
Authors: Sprouse Alyssa A. , Herbert Brittney-Shea 
Published: August 2012

Abstract
Treatment of drug-resistant cancer cells remains a difficult problem in cancer therapy because most resistant cells can pump out drugs or upregulate other survival pathways to bypass a targeted therapy. The polyphenol natural compound, resveratrol, has been shown to inhibit cell growth of multiple cancer types, but it is not cytotoxic to normal cells. However, the effects of resveratrol in triple negative breast cancer cells (estrogen receptor-, progesterone receptor-, and HER2-negative) as well as cancers that are resistant to the common cancer drug, paclitaxel, are not well understood. In this study, the effects of resveratrol were investigated in the triple negative breast cancer cell line MDA-MB-231 as well as a novel MDA-MB-231 derived paclitaxel-resistant line generated in our laboratory. Assays for cell proliferation, apoptosis, and protein expression changes related to apoptosis and survival were utilized in order to determine the differential effects of resveratrol on the parental and resistant cell lines. At lower (&lt; 10 μM) concentrations, resveratrol induced cell proliferation in both cell lines, consistent with other studies demonstrating lifespan extension of normal cells with resveratrol treatment. On the other hand, after treatment with 10-100 μM concentrations of resveratrol, both cell lines exhibited a reduction in cell proliferation, with the paclitaxel-resistant cells to a greater extent. In addition, resveratrol decreased the ability of both cell lines to form colonies when plated at low density (an indication of reduced cell survival capacity). Furthermore, resveratrol treatment increased the amount of DNA fragmentation associated with apoptosis compared to untreated controls in both cell lines, but the paclitaxel resistant cells were more sensitive to resveratrol treatment than the parental cells. By protein expression analyses, we observed that in both the parental and paclitaxel-resistant cell lines, resveratrol may be acting through NAD-dependent deacetylase sirtuin (SIRT1) activity by decreasing the expression of the inhibitor-of-apoptosis protein, surviving and increasing the activator-of-apoptosis, caspase 3. Based on these data, we propose that resveratrol can inhibit proliferation and induce apoptosis in triple negative breast cancer cells, including paclitaxel-resistant cells. These results provide rationale for the use of resveratrol as an important starting point for the development of a novel anti-cancer agent for drug resistant, aggressive cancers as well as in combination with other anti-cancer drugs without significant toxicity to normal cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5676. doi:1538-7445.AM2012-5676
Abstract 5677: A comparative study of the interaction of the maytansinoid, DM1-Me, vinblastine, and taxol with human cells
Authors: Audette Charlene , Kovtun Yelena , Goldmacher Victor S. 
Published: August 2012

Abstract
The current interest in antimitotic compounds that interact with microtubules is caused, in part, by their clinical importance in oncology. Several microtubule-binding compounds, including Vinca alkaloids, taxanes, maytansinoids, and auristatins, are in clinical use, some additionally being evaluated as antibody conjugates. To better understand the factors that determine the potency of antibody-maytansinoid conjugates in killing cells, we examined the interaction of the maytansinoid, DM1-Me, with MCF7 cells, in comparison with vinblastine and taxol. DM1-Me was more potent in arresting mitosis than vinblastine or taxol (5- and 13-fold, respectively). We compared the levels of accumulation of these three compounds by MCF7 cells following a 24 hour exposure at the mitotic IC50 concentration and found that, at this concentration, cells accumulated comparable amounts of vinblastine and DM1-Me, but required more than a 10-fold greater concentration of taxol to achieve a similar effect. Additionally, cells exposed to each compound for 2 hours prior to being washed into drug free medium, retained most of the accumulated DM1-Me or taxol for at least 24 h, while most vinblastine was released into the medium within the first 2 h. DM1-Me and taxol had similar affinities for MCF7 cells, while that of vinblastine was 4-6-fold lower. These properties of DM1-Me, vinblastine and taxol suggest that maytansinoids are a better choice for antibody conjugates than vinblastine or taxol, a conclusion which is consistent with the experimental data and clinical experience with antibody conjugates made with compounds of these three classes.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5677. doi:1538-7445.AM2012-5677
Abstract 989: The crosstalk of mTOR/S6K1 and Hedgehog pathways
Authors: Wang Yan , Xia Weiya , Lang Jing-Yu , Hsu Jennifer , Wang Huamin , Ajani Jaffer , Hung Mien-Chie 
Published: August 2012

Abstract
Esophageal adenocarcinoma (EAC) is the most prevalent esophageal cancer type in the United States, and TNFα/mTOR pathway is known to mediate the development of EAC. Additionally, aberrant activation of Gli1, downstream effector of hedgehog pathway, has been observed in EAC. In this study, we found that activated mTOR/S6K1 pathway promotes Gli1 transcriptional activity and oncogenic function through S6K1-mediated Gli1 phosphorylation at Ser84, which releases Gli1 from its endogenous inhibitor, SuFu. Moreover, elimination of S6K1 activation by mTOR pathway inhibitor enhances the killing effects of the hedgehog pathway inhibitor. Together, our results established a crosstalk between mTOR/S6K1 and the hedgehog pathways, which provides not only a new mechanism for non-canonical hedgehog pathway but also a rationale for combination therapy for EAC.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 989. doi:1538-7445.AM2012-989
Abstract 99: Posttranslational modification of the RBBP6 isoform 3 is required for excessive cell proliferation
Authors: Dlamini Zodwa , Mbita Zukile 
Published: August 2012

Abstract
RBBP6 isoform 3 belongs to a family of RBBP6 cell cycle-related proteins. There are 3 human RBBP6 isoforms; iso 1, 2 and 3, transcribed from RBBP6 mRNA variants 1, 2 and 3 respectively. RBBP6 isoform 1 has been shown to be a pro-apoptotic protein while the function of isoform 2 has not been confirmed. Recently isoform 3 has shown to be involved in G2/M cell cycle regulation and is deregulated in human cancers. This study aimed at investigating how the RBBP6 isoform 3 regulates cell proliferation. Cell culture and transfections were used to determine the effect of RBBP6 isoform 3 on cell cycle progression. RBBP6 variant 3 mRNA was cloned into a pCDNA3.1/Zeo (+) vector and expressed in human kidney embryonic cells, Hek 293T. Cell cycle and cell counts analysis were conducted by using Flow Assorted Cell Sorting (FACS). Western blotting analysis was used to analyse RBBP6 isoform 3 using a polyclonal antibody against RBBP6 isoform 3 N-terminal region. Transfection of Hek 293T cells with RBBP6 variant 3 mRNA resulted in temporal G2/M cell cycle arrest. This cell cycle arrest ceased after 48 hours and Western blotting showed that RBBP6 isoform 3 was posttranslationally modified through either glycosylation or phosphorylation or both. Mass spectrometry confirmed that the higher molecular weight protein was indeed RBBP6 isoform 3. This higher molecular weight product was accompanied by excessive cell proliferation. This result suggests that cancer cells use this posttranslational modification to bypass G2/M cell cycle arrest. RBBP6 isoform 3 could therefore be targeted for new anti-cancer therapeutic strategies.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 99. doi:1538-7445.AM2012-99