bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1022: PI3-kinase inhibition enhances ABT-737-induced apoptosis in colorectal cancer cell lines
Authors: Morrow Christopher J. , Hou Jian-Mei , Dive Caroline 
Published: February 2011

Abstract
The PI3-kinase signalling pathway is widely reported to promote survival, proliferation and migration. This pathway is up-regulated in several solid tumours by a host of different mechanisms, including PTEN deletion, RAS or PIK3CA mutation and aberrant activation of receptor tyrosine kinases. As such, inhibitors of PI3-kinase and its down-stream effectors are of great interest as tractable anti-cancer agents. The effect of PI3-kinase inhibition was investigated in colorectal cancer cell lines and demonstrated that, while PI3-kinase inhibition by itself did not cause cell death, it enhanced apoptosis induced by the BH3 mimetic ABT-737 (assessed by nuclear fragmentation, caspase 3 cleavage and phosphatidylserine exposure). Furthermore, ABT-737 and PI3-kinase inhibition caused increased level of Bak activating conformational change compared to ABT-737 alone, suggesting that the effect of PI3-kinase inhibition is up-stream of cytochrome C release. PI3-kinase inhibition did not alter the expression level of Bcl-2 family members, but co-immunoprecipitation revealed that it increased the amount of Bim bound to Bcl-xL. No change was seen in the binding of other BH3 only proteins or of Bax or Bak to ABT-737 targets Bcl-2 or Bcl-xL. ABT-737-induced apoptosis was independent of AKT and mTOR signalling as it was unaffected by the inhibitors AKTi1/2 and rapamycin respectively. A model is proposed whereby ABT-737 interrupts PI-3K inhibition-induced Bim/Bcl-xL complexes to promote apoptosis via Bax/Bak activation. Function testing experiments are underway to interrogate this model.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1022.
Abstract 1026: A non-apoptotic function for Mcl-1 as an activator of canonical Wnt signaling in keratinocytes
Authors: Sitailo Leonid , Sethupathi Periannan , Denning Mitchell F. 
Published: February 2011

Abstract
Mcl-1 is an anti-apoptotic Bcl-2 family member whose rapid down-regulation is required for UV apoptosis. We recently showed that not only is Mcl-1 a major human keratinocyte (KC) survival protein, but it is required for proper KC differentiation in organotypic culture, implicating a non-apoptotic function for Mcl-1 involved in regulating epidermal morphogenesis. To further explore the function of Mcl-1 in vivo, we generated and analyzed transgenic mice expressing human Mcl-1 under control of the keratin 5 (K5) promoter. K5-Mcl-1 transgenic mice had &gt;2-fold increase in epidermal thickness (p&lt;0.001), increased basal KC BrdU incorporation (∼2-fold) and altered expression of KC differentiation markers. Several K5-Mcl-1 mice developed benign follicular cysts. Since both proliferation and hair follicle morphogenesis are features of increased Wnt/β-catenin signaling, we examined components of the Wnt/β-catenin pathway. Epidermises from K5-Mcl-1 mice had elevated steady state β-catenin, P-GSK3β (Ser9, Ser21) and P-Akt (Ser473), consistent with Wnt pathway activation. To assess Wnt pathway in more detail, we over-expressed Mcl-1 in human KCs by retroviral transduction. Over-expression of Mcl-1, but not Bcl-2 or Bcl-xL, also induced KC proliferation (3.3-fold). Mcl-1 increased the levels of total and active β-catenin, c-Myc, P-GSK-3β, and P-Akt, as well as inducing TCF-4-dependent luciferase reporter activity (p&lt;0.05) in keratinocytes. Q-RT-PCR analysis of Wnt pathway genes identified Disheveled-1, Frizzled-1 and Cyclin D3 as the most highly up-regulated genes common to both Mcl-1 transduced human KCs and K5-Mcl-1 mice. Mcl-1 truncation mutants encoding the N-terminal 208 and 103 amino acids, but lacking the BH domains, were generated and over expressed in KCs. Both Mcl-1 mutants induced 3H-thymidine incorporation (3.4- and 2.9-fold respectively), indicating that the mitogenic activity of Mcl-1 resides in its N-terminal region. Since β-catenin signaling is activated in cutaneous SCC and involved in stem cell maintenance, this non-apoptotic function of Mcl-1 represents a novel and potentially oncogenic activity in addition to its well characterized anti-apoptotic function.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1026.
Abstract 1031: Sphingolipid metabolism as a therapeutic target in chemotherapy resistant and hormone therapy resistant breast cancer
Authors: Gestaut Matthew M. , Antoon James W. , Ponnapakam Adharsh P. , J Liu , Burow Matthew E. , Foroozesh Maryam , Beckman Barbara S. 
Published: February 2011

Abstract
Endocrine- and chemo-resistance are major causes for failure of treatment in recurrent breast cancer. Normal apoptotic pathways targeted by chemotherapeutic agents become altered, diminishing their efficacy and increasing resistance mechanisms. The proapoptotic sphingolipid compound N-Octanoyl-D-erythro-sphingosine (C8-ceramide) mimics endogenous long chain ceramide and is a potent drug in endocrine-/chemo-resistant breast cancer cells. In this study, we examined basal expression levels of modifier enzymes for endogenous ceramide regulation across drug sensitive, chemoresistant and hormone therapy- resistant breast cancer cells lines. Differences were found among UDP-galactose ceramide galactosyltransferase, sphingosine kinase-1, and acid sphingomyelinase gene expression in: MCF-10A, MCF-7, MDA-MB-231 and MCF-7TN-R cell lines. Using C8-ceramide as the lead compound, 8 novel ceramide analogs were synthesized with either enol or amide backbone substitutions and tested for biological activity. The enol substitution was found to be the most potent, with (2S,3R,E)-2-((E)benzylideneamino)octadec-4-ene1,3-diol (Analog C) displaying the greatest reduction in proliferation. Analog B appeared to be the most potent cytotoxic drug in MCF-7 and MDA-MB-231 cell lines with IC50 values of 6.2uM and 3.0 uM respectively. In the cytotoxicity assay MCF-7TN-R cell line, Analog A appeared to be the most potent with an IC50 of 2.4uM. The clonogenic proliferation assay provided very different, yet promising results. Analog D had the lowest IC50 of 460nM in MDA-MB-231, Analog C had an IC50 of 100nM in MCF-7TN-R, and Analog A had an IC50 of 1.48uM in the MCF-7 breast cancer cell line. All of the IC50s for proliferation assays were at least an order of magnitude more potent than the control drug C8 (IC50 of 5uM). Due to the potency of these drugs, these results exemplify the potential of novel ceramide-targeted therapies in chemo-resistant and endocrine-resistant breast cancer cell lines.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1031.
Abstract 1043: Autophagy induces cytoprotection in cisplatin-treated lung cancer cells
Authors: Yang Sei-Hoon , Jang Hye Yeon , Jo Hyang Jeong , Lee Kang Kyoo , Moon Sun Rock , Kim Hak Ryul , Jeong Eun Taik , Lee Hyun Kyung , Park Soon A 
Published: February 2011

Abstract
Purpose: Most of lung cancer patients had received the systemic chemotherapy because they had diagnosed the advanced stage at presentation. Cislplatin-based chemotherapy is main regimen for advanced lung cancer. But serious adverse reaction (SAE) had occurred after chemotherapy. This is main reason for chemotherapy withdrawal. If we will use the reduced dose of cispaltin, cisplatin-based the chemotheray will be continued. To figure out whether the effect of low dose of cisplatin will be synergistically enhance by autophagy inhibiton, even though the reduced dose of cisplatin less effect for treatment response, We investigated that role of autophagy by 3-methyladenine, class III PI3kinase inhibitor in cisplatin-treated lung cancer cells. Methods: Lung cancer cells were incubated with normal media and treated the 5uM (LD20) and 20uM(LD50) of cislpaltin according to time dependent. We examined the sensitivity to low or high doses of cisplatin treatment using the MTT cell viability assay and compared apoptosis and autophagy by nuclear stianing, apoptotic or autophagic related proteins or autophagic vacuoles. autophagy is also displayed the development of acidic vascular organelles by acridine orange and the fluorescent expression of GFP-LC3 protein in the GFP-LC3 transfected cells. Result: Low dose of cisplatin-treated lung cancer cells is relatively less sensitive to cell death rather than high dose treated cells in a time-dependent manners. We didnot find out the nuclear fragmentation in lower dose even though detected its in high dose. PARP cleavages also were not detected in low dose of cisplatin exception 24H. We observed that massive vacuolization in the cytoplasm were seen at lower dose treated cells. Acridine orange stain-positive cells also were increased according to time dependent. We figured out that the autophagosome-incorporated LC3 II protein expression more increased in low dose treated cells (24H to 48H) in spite of no detection of LC3 II in high dose treated cells. The expression of GFP-LC3 were increased in 5uM treated cells by time-dependent manner. When 3-methyladenine, class III PI3kinase inhibitor, was pretreated in 5uM cisplatin-treated lung cancer cells, cell survival significantly were decreased. Conclusion: Autophagy induces cytoprotection in lower dose of cisplatin-treated lung cancer cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1043.
Abstract 1047: Circadian disruption induced by light at night upregulates PCNA expression in tissue-isolated human breast cancer xenografts in nude rats
Authors: Wu Jinghai , Dauchy Robert T. , Tirrell Paul C. , Wu Steven S. , Dauchy Erin M. , Blask David E. , Greene Michael W. 
Published: February 2011

Abstract
The circadian system and the cell cycle are two global regulatory systems in animals and humans. Previous studies have shown that disruption of either the circadian system or the cell cycle increases the risk of cancer in humans. However, the molecular mechanisms of circadian-mediated cell cycle dysregulation are not completely understood. Because proliferating cell nuclear antigen (PCNA) plays an essential role in DNA replication and cell cycle regulation, we studied the circadian regulation and disruption of PCNA in an in vivo animal model of human breast cancer. In tissue-isolated ER- MCF-7 human breast cancer xenografts grown in female nude rats exposed to a normal 12L:12D circadian condition, PCNA protein levels were maximal in the morning (2 h after lights on) but remained at very low levels throughout the rest of the 24 h period. To determine whether circadian disruption alters PCNA protein expression, xenograft-bearing nude rats were exposed to low intensity of light at night (LAN) (0.08 μW/cm2). PCNA protein was continuously expressed at a high level throughout the 24 h period in breast cancer xenografts growing in nude rats exposed to the LAN. Exposure of tumor-bearing rats to LAN also resulted in significantly accelerated growth of these xenografts. Moreover, several signaling cascades related to cell growth were examined. Daily rhythms of Akt and MAPK activation in the human breast cancer tumors were disrupted by LAN but did not track the changes in PCNA expression; however, PDK1 activation directly correlated with PCNA expression. Expression of PKCδ and PKCα, downstream targets of PDK1, was differentially elevated by LAN in xenografts in a manner consistent with their reported roles in cell proliferation. In contrast, LAN did not disrupt the rhythmic expression of either PCNA, PKCδ, or PKCα in the liver of the tumor-bearing rats. Expression of insulin-like growth factor 1 receptor (IGF-1R) protein, an upstream signaling molecule for PDK1, also correlated with the expression pattern of PDK1/PKC/PCNA in tumor-bearing rats exposed to LAN. Exposure of tumor-bearing rats to LAN disrupted the circadian rhythm of IGF-1R protein levels in the liver. Finally, circulating IGF-1 concentrations showed circadian disruption in LAN-exposed tumor-bearing nude rats. Thus, interruption of the IGF-1 signaling pathway may constitute a novel molecular mechanism of circadian regulated tumor growth. Taken together, our results suggest that LAN-induced disruption of circadian rhythms in cell signaling cascades accelerates tumor growth in vivo through continuous up-regulation of PCNA.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1047.
Abstract 1052: RNAi-mediated mutual regulation of FGF-2 and its antisense gene, NUDT6, in C6 glioma cells.
Authors: Baguma-Nibasheka Mark , Murphy Paul R. 
Published: February 2011

Abstract
Basic fibroblast growth factor (FGF-2) is a potent wide-spectrum antiapoptotic mitogen, and the dysregulation of its expression is associated with cell proliferation and immortalization in a wide variety of tumors. We have previously reported that FGF-2 and NUDT6, the product of its antisense gene, are co-localized and inversely expressed in C6 glioma cells, and that constitutive overexpression of NUDT6 suppresses cellular FGF-2 expression, nuclear translocation, and the resumption of cell cycles (Baguma-Nibasheka et al., Mol Cell Endocrinol, 267:127-136, 2007). For the current report, we investigated the role of the endogenous RNAi machinery in mediating the post-transcriptional effects of NUDT6 on FGF-2 expression. FGF-2 knockdown was accompanied by a significant (&gt;3 fold) increase in NUDT6 mRNA, and vice versa. Similar converse effects were observed on the cognate protein levels, as assessed by confocal immunoflourescence, Western blotting, and flow cytometry, indicating that these two transcripts may be mutually regulatory. Remarkably, knockdown of either transcript reduced cell proliferation and inhibited S-phase re-entry following serum deprivation (Table 1), indicating that both FGF-2 and NUDT6 may be involved in the regulation of cell cycle progression. Supported by the CIHR and NSERC.Table 1.S-Phase Percentages1 of C6 Cells following Knockdown and G0 Arrest.Hours after Return to 10% FBS Medium0361224Control siRNA4.8 ± 0.516.8 ± 1.321.6 ± 1.822.4 ± 1.123.0 ± 1.5NUDT6 siRNA4.1 ± 0.510.6 ± 1.3*14.2 ± 1.6*16.7 ± 1.8*19.8 ± 0.8FGF-2 siRNA3.5 ± 0.55.9 ± 0.8*6.9 ± 1.2*11.2 ± 1.1*14.5 ± 1.0*1mean ± SEM. * = significantly different from control; p&lt;0.05, n=3.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1052.
Abstract 1053: Modulation of Wnt/β-catenin signaling pathway by Cripto-1 in mouse embryonal carcinoma F9 cells
Authors: Nagaoka Tadahiro , Watanabe Kazuhide , Gonzales Monica , Castro Nadia , Rangel Maria-Cristina , Rollman Kelly , Rubin Jeffrey S. , Salomon David S. , Bianco Caterina 
Published: February 2011

Abstract
Cripto-1 is a membrane bound protein that belongs to the epidermal growth factor (EGF)-CFC (Cripto/FRL-1/cryptic) protein family. Cripto-1 is a co-receptor for the transforming growth factor-β related protein Nodal and together with Nodal induces Smad-2/3 phosphorylation through the serine-threonine kinase receptor ALK-4. Furthermore, Cripto-1 can also bind to Glypican-1, Caveolin-1, GRP78, TGFβ1, Activin, Notch and Wnt11 proteins. In the present study, 3xFLAG-tagged human Cripto-1 and HA-tagged Wnt proteins (Wnt-1, 3a, 5a and 11) were co-expressed in 293T cells and co-immunoprecipitation was carried out using anti-FLAG or anti-HA antibodies. All four Wnt proteins were found to bind to Cripto-1. We also evaluated whether Cripto-1 could bind to the Wnt receptor, Frizzled-8 cysteine rich domain and the Wnt co-receptor, LRP5 in 293T cells. LRP5 was found to co-immunoprecipitate with Cripto-1 in transiently transfected 293T cells, while no binding of Cripto-1 to Frizzled-8 was detected. Finally, we investigated the biological significance of the interaction between various Wnts and Cripto-1 using mouse embryonal carcinoma F9 cells that express high levels of endogenous Cripto-1 protein and Cripto-1 gene null F9 (F9 Cr-1-/-) cells. Interestingly, we found that F9 cells contained more stabilized cytoplasmic β-catenin than F9 Cr-1-/- cells after the cells were treated with Wnt3a protein. Super TOP-FLASH reporter assays also revealed a significant increase in luciferase activity in F9 cells compared to F9 Cr-1-/- cells following Wnt3a treatment. In conclusion, our results demonstrate that Cripto-1 can enhance the canonical Wnt/β-catenin signaling pathway in mouse embryonal carcinoma cells. Therefore, modulation of the canonical Wnt/β-catenin pathway by Cripto-1 might perform an important role in embryonic stem cells and embryonal carcinoma cells that are expressing high levels of Cripto-1.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1053.
Abstract 1057: BRMS1 restoration of gap junctional intercellular communication involves modulation of KATP channels and downregulation of phosphoinositide 3-kinase (PI3K)
Authors: Bodenstine Thomas M. , Vaidya Kedar S. , Ismail Aimen , Cook Leah M. , Welch Danny R. 
Published: February 2011

Abstract
Metastatic disease remains the most lethal aspect of cancer, accounting for over 90% of cancer related mortality. Breast Cancer Metastasis Suppressor 1 (BRMS1) specifically inhibits the ability of tumor cells to metastasize to secondary sites while having little or no affect on primary tumor growth. Clinically, a loss of BRMS1 mRNA expression in breast cancer patients is correlated with poor prognosis and a decrease in BRMS1 protein levels predicts reduced disease free survival. The mechanisms of BRMS1 remain unclear; however expression of BRMS1 significantly decreases the PI3K signaling pathway, a pathway that is often over activated in cancer cells. PI3K is a lipid kinase that phosphorylates phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2) to PtdIns(3,4,5)P3, leading to downstream signaling. BRMS1 acts to reduce the substrate of PI3K, PtdIns(4,5)P2, by &gt;90% when expressed in metastatic cells. Re-expression of BRMS1 in cancer cell lines also restores gap junctional intercellular communication (GJIC), a process that mediates cellular homeostasis and is often lost during neoplastic progression. GJIC has been shown to be affected by PI3K; thus we hypothesized that inhibition of PI3K signaling by BRMS1 might be responsible for the restoration of GJIC. In support of this, treatment with the PI3K inhibitor LY294002 (10µM) in vector control and parental cell lines from multiple cancer cell types, mimicked the effects of BRMS1 on GJIC. Interestingly, inhibition of signaling molecules further downstream of PI3K (AKT, mTOR) did not produce the same effect, suggesting the mechanism of action may directly involve the ratio of PtdIns(4,5)P2/PtdIns(3,4,5)P3. We show that alterations in an ATP dependent potassium channel, KATP, regulated by phosphoinositides, is responsible for the changes in GJIC observed by BRMS1 expression. Delineation of this mechanism will allow for in vivo analysis to determine if changes in GJIC are causative for the BRMS1 mediated suppression of metastasis. Taken together, our data suggest an inhibitory mechanism on gap junctional communication mediated by PI3K, that is relieved by restoration of BRMS1 expression.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1057.
Abstract 1061: Glutathione S-transferase P1 is required for growth and survival of human glioma cells
Authors: Ali-Osman Francis , Liu Jiewu 
Published: February 2011

Abstract
Overexpression of glutathione S-transferase p1 (GSTP1), a protein involved in Phase II metabolism and cell signaling, is a hallmark of diverse human malignancies, including gliomas, and is associated with resistance to therapy, aggressive tumor growth and poor patient survival. Although, the function of GSTP1 in drug metabolism and detoxification is well documented, its role in regulating tumor cell growth remains unclear. Here, we report that in human glioma characterized by high GSTP1 expression, GSTP1 is obligately required for the growth and survival of the tumor cells. For this, we stably infected cells of the MGR3 glioblastoma multiforme (GBM) cell line that expresses high de novo levels of GSTP1, with a lentiviral vector that either expresses a short hairpin RNA (shRNA) specifically targeting to GSTP1 or a control shRNA. We isolated two clones, 1 and 2 and showed by western blotting that the GSTP1 specific shRNA mediated decreases in GSTP1 expression of 92% and 100%, respectively, relative to controls while infected with eGFP shRNA. Growth kinetic analysis showed the in vitro growth rates of both clones 1 and 2 to be significantly lower than that of the parental or control clone, with population doubling times of 108.9 ± 17.6 hr for clone 1 and 94.8 ± 4.3 hr for clone 2, compared with 40.6 ± 2.6 hr for the parental cells and 44.7 ± 2.0 hr for the control transfected cells. Cell cycle analysis showed that the GSTP1 knockdown induced a significant almost 2-fold increase in the sub-G1 (apoptotic) population that correlated with an increase in caspase 3/7 activation. Western blotting showed no significant changes in total protein levels of ERK, JNK and p38 MAPK following GSTP1 knockdown, however, phosphorylation levels of both ERK1/2 and JNK1/2 increased significantly, while phospho- p38 MAPK levels did not change. JNK downstream signaling, viz., phosphorylation of c-Jun, increased dramatically in cells of the two clones. These alterations in MAPK signaling in the tumor cells associated with GSTP1 silencing correlated with the decreased survival and growth kinetics and corresponding changes in apoptosis/survival signals, including, decreased bcl2 and increased bax levels in the tumors. Our results show that GSTP1 is required for cell survival and growth of human GBM cells that naturally over-express high GSTP1 levels. This is consistent with the aggressive tumor growth and poor survival of patients whose tumors contain high levels of GSTP1 and provide a rationale for targeting GSTP1 as a potential therapeutic strategy for malignant gliomas.
Supported by grants RO1CA112519, RO1CA127872, RO1CA91438, P30CA114236 and P5OCA108786 from the National Institutes of Health (USA).
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1061.