bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1732: PI3K inhibition potentiates ABT-737 induced apoptosis in colorectal cancer cells independent of MCL1 downregulation or AKT/mTOR inhibition.
Authors: Potter Danielle S. , Kelly Paul J. , Denneny Olive A. , Dive Caroline , Morrow Christopher J. 
Published: August 2014

Abstract
Background
Colorectal cancer (CRC) is the third most common cancer and is a leading cause of morbidity worldwide. The five year survival rate of patients with advanced or metastatic CRC is less than 5%, identifying the need for new and improved therapies in the treatment of advanced and metastatic CRC. Phosphoinositide 3-kinase (PI3K) signaling has been implicated in several hallmarks of cancer, such as sustained proliferation, resisting cell death and invasion, and is frequently deregulated in CRC via a mutation of effectors such as PIK3CA, PIK3R1 and PTEN, making it an attractive therapeutic drug target. Despite this, inhibition of PI3K signaling does not cause cell death in CRC cells. Furthermore, CRC cells are relatively resistant to the BH3 mimetic ABT-737, which directly targets the BCL2 family of proteins inducing apoptosis via the mitochondrial pathway. Therefore, we investigated whether combining PI3K inhibitors and ABT-737 in CRC cells might synergise to induce apoptosis.
Results
PI3K inhibition enhanced ABT-737 induced apoptosis by 2.3-4.5 fold and reduced expression levels of Mcl-1, an established resistance biomarker for ABT-737. PI3K inhibition enhanced ABT-737-induced apoptosis a further 1.4-2.4 fold in CRC cells with siRNA depleted Mcl-1 suggesting contributory mechanisms additional to Mcl-1 down regulation. PI3K inhibition increased levels of Bcl-xL bound BimEL independently of Mcl-1 depletion. Further investigations are being carried out to determine whether this is the cause of increase ABT-737 sensitivity. ABT-737-induced apoptosis was unaffected by inhibition of PI3K downstream effectors AKT and mTOR. A siRNA library screen has been conducted to identify proteins downstream of PI3K which affect ABT-737 sensitivity and the results will be reported.
Conclusions
These data reveal a PI3K inhibition enhanced, ABT-737 driven apoptosis that occurs via Mcl-1, AKT and mTOR independent mechanism(s) consistent with increased association of BimEL and Bcl-xL. Further work is ongoing to elucidate the molecular mechanisms that underpin enhanced response to this BH-3 mimetic in CRC.
Citation Format: Danielle S. Potter, Paul J. Kelly, Olive A. Denneny, Caroline Dive, Christopher J. Morrow. PI3K inhibition potentiates ABT-737 induced apoptosis in colorectal cancer cells independent of MCL1 downregulation or AKT/mTOR inhibition. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1732. doi:10.1158/1538-7445.AM2013-1732
Abstract 1739: Unexpected complexity in Mcl-1 phosphorylation in response to microtubule inhibitors.
Authors: Chu Rong , Chambers Timothy C. 
Published: August 2014

Abstract
Microtubule inhibitors promote phosphorylation and degradation of Mcl-1, and the loss of expression of this key anti-apoptotic Bcl-2 family member appears to be critical for apoptosis induction. While several sites and kinases have been implicated, a phosphorylation/degradation-resistant mutant has not been definitively described. Contrary to previous reports suggesting that Thr92 phosphorylation by Cdk1 regulates Mcl-1 degradation, a Thr92Ala Mcl-1 mutant expressed in HeLa cells was phosphorylated and degraded with the same kinetics as wild-type following vinblastine-treatment. Similarly, when Mcl-1 with alanine replacements of five putative major sites (S64, T70A, T92, S121, T163) was expressed, it was phosphorylated and degraded like the wild-type. These results suggested redundancy or the existence of additional regulatory sites. To analyze Mcl-1 phosphorylation in more detail, cell extracts, made using a novel extraction solution to improve resolution, were subjected to 2D-PAGE/immunoblotting. Extracts from asynchronous control cells showed one major and two minor, more acidic, spots, the latter sensitive to acid phosphatase treatment. Extracts from vinblastine-treated cells showed up to 9 distinct spots all but two of which were eliminated after acid phosphatase treatment. These results reveal an unexpected complexity in Mcl-1 phosphorylation in response to microtubule inhibitors and the existence of many more sites than previously suspected. Identification of the additional sites of phosphorylation, the kinase(s) responsible, and their role in regulation of Mcl-1 degradation are ongoing.
Supported by NIH CA109821.
Citation Format: Rong Chu, Timothy C. Chambers. Unexpected complexity in Mcl-1 phosphorylation in response to microtubule inhibitors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1739. doi:10.1158/1538-7445.AM2013-1739
Abstract 1741: Mitotic catastrophe and inhibition of growth of Castration Resistant Prostate Cancers by a dietary agent Withaferin-A.
Authors: Vadodkar Aditi Shirish , Suman Suman , Roy Ram Vinod , Damodaran Chendil 
Published: August 2014

Abstract
Cell cycle deregulation has been strongly associated with the pathogenesis of prostate cancer. It has been well documented that an increased expression of cell cycle regulatory proteins (cyclin D1-25%, cyclin A-35% and cyclin B-75%) have been reported in castration resistant prostate cancer (CRPC) cells, when compared to normal prostate tissue. There are several cell cycle regulators undergoing clinical trials targeting either G0/G1 or G2/M phase of cell cycle to inhibit the growth of many cancers including prostate cancer. We previously published that Withaferin-A (WA); a natural compound effectively suppresses CRPC growth both in vitro and in vivo. Hence, in this study we intend to determine the cell-cycle regulatory potential of this agent on CRPC cells. WA caused irreversible G2/M arrest in both CRPC cell lines (PC-3 and C4-2B) till 72 hours . Phosphorylation of cdc2 by Wee1 and Myt1 is an important step to maintain an inactive state of cdc2 that lead to G2/M cell cycle arrest. Additionally decreased levels of phosphorylated Wee-1 and Myt1 followed by increase in the phosphorylation status of cdc2 (Tyr15 and Thr14) supported the G2/M phase of cell cycle arrest in both CRPC cell lines. Further checkpoint kinase assay showed increased activity in WA treated CRPC cells suggesting activation of CDC25C that activates cyclinB/cdc2 complex .We also observed down regulation of several cyclin family proteins in both CRPC cells. Altogether, these results conclude d that WA inhibits CRPC cell growth by induction of G2/M cell cycle arrest, highlighting the potential of WA could be a therapeutic agent for CRPC. Currently, we are investigating the effect of WA on cell cycle markers using both xenograft and TRAMP models. The outcome of our study may enable bringing WA to the mainstream of medicine for prevention and/or therapy for CRPC.
Citation Format: Aditi Shirish Vadodkar, Suman Suman, Ram Vinod Roy, Chendil Damodaran. Mitotic catastrophe and inhibition of growth of Castration Resistant Prostate Cancers by a dietary agent Withaferin-A. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1741. doi:10.1158/1538-7445.AM2013-1741
Abstract 1742: Potential roles of histone deacetylase 11 in cell cycle regulation and cancer.
Authors: Srikumar Thejal , Telles Elphine , Seto Edward 
Published: August 2014

Abstract
Histone deacetylases (HDACs) are enzymes that deacetylate lysine residues on histone and non-histone proteins. They regulate various cellular functions including transcriptional regulation, cell proliferation, apoptosis, and cellular metabolism. Broad spectrum HDAC inhibitors, including Vorinostat and Romidepsin, have been approved for cancer therapy, but their use is limited due to toxicity and side effects. A deeper understanding of the function of individual histone deacetylases could lead to the development of more specific and potentially more effective anti-cancer agents. In this context, Histone Deacetylase 11 (HDAC11) could be a potential target for anticancer therapeutics. HDAC11 is the most recently discovered Histone Deacetylase and, therefore, the least characterized among the 18 HDACs. Its expression is altered in various cancers and recent studies have suggested that HDAC11 might inhibit the activity and function of the DNA replication licensing factor Cdt1. To examine whether HDAC11 controls Cdt1-mediated cell cycle regulation, HDAC11 was overexpressed in human U87 glioblastoma cells. We found that overexpression of HDAC11 represses Cdt1 expression levels. Most importantly, we observed that HDAC11 overexpression promotes earlier cell entry into the G2/M phase of the cell cycle than non-HDAC11-overexpressed cells. Finally, we discovered that HDAC11 levels change throughout the cell cycle in a manner that is contrary to the Cdt1 expression levels. These results indicate that HDAC11 negatively regulates Cdt1, and uncover an important and previously unknown role of this enzyme in cell cycle regulation. Together, our findings suggest that development of drugs that target HDAC11 might be a viable strategy for overcoming cancers where this protein is overexpressed.
Citation Format: Thejal Srikumar, Elphine Telles, Edward Seto. Potential roles of histone deacetylase 11 in cell cycle regulation and cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1742. doi:10.1158/1538-7445.AM2013-1742
Abstract 1748: Cyclin D1 harboring T286I mutation promotes oncogenic activation in endometrial cancer.
Authors: Ikeda Yuji , Oda Katsutoshi , Koso Takahiro , Miyasaka Aki , Kashiyama Tomoko , Hiraike-Wada Osamu , Maeda Daichi , Kawana Kei , Nakagawa Shunsuke , Tetsu Osamu , Kikuchi Yoshihiro , Fujii Tomoyuki , Yano Tetsu , Kozuma Shiro 
Published: August 2014

Abstract
Introduction. Cyclin D1 is an important regulator of cell cycle progression. Phosphorylation of cyclin D1 at Thr-286 by GSK3beta triggers nuclear export and its cytoplasmic proteolysis via the 26S proteasome. Cyclin D1 overexpression is a common event in various types of human cancers; however,mutations of CCND1 (encoding cyclin D1) have been only reported in endometrial cancer and esophageal cancer. We previously reported T286I mutations of CCND1 in 2 endometrial carcinomas (2.3%). The objective of this study was to identify the functions of T286I mutant of cyclin D1 in endometrial cancer. Materials and methods. T286I mutant cyclin D1 (CD1-T286I) plasmid was generated using wild-type cyclin D1 (CD1-WT) plasmid via site-directed mutagenesis technique. pcDNA3 empty plasmid was used as a control (CD1-Ct). Using these plasmids, the functions of mutant CD1-T286I were analyzed by luciferase assays, immunofluorescence, western blotting and colony formation assays in HEK293T (kidney) and HEC-50B (endometrial cancer) cells, both of which do not possess CCND1 mutations. Statistical analysis was performed by student-T test and p&lt;0.05 was considered statistically significant. Result. Immunofluorescence and western blotting showed predominant accumulation of exogenous CD1-T286I in nucleus, whereas expression of exogenous CD1-WT and endogenous cyclin D1 were observed diffusely in cytoplasm and nucleus. Luciferase assay revealed that pRB1 expression was partially decreased by introduction of CD1-WT and that the pRB1 expression was further decreased by introduction of CD1-T286I (p=0.002). In colony formation assays, introduction of CD1-T286I significantly increased the colony number, compared with CD1-WT (p=0.007) and CD1-Ct. Conclusion. Stabilization and accumulation of mutant cyclin D1 (T286I) in the nucleus might overcome regulation by pRb and induce cell proliferation in certain endometrial cancers. Phosphorylation-dependent nuclear export of cyclin D1 at Thr286 might be critical for prevention of aberrant cell proliferation in human cells.
Citation Format: Yuji Ikeda, Katsutoshi Oda, Takahiro Koso, Aki Miyasaka, Tomoko Kashiyama, Osamu Hiraike-Wada, Daichi Maeda, Kei Kawana, Shunsuke Nakagawa, Osamu Tetsu, Yoshihiro Kikuchi, Tomoyuki Fujii, Tetsu Yano, Shiro Kozuma. Cyclin D1 harboring T286I mutation promotes oncogenic activation in endometrial cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1748. doi:10.1158/1538-7445.AM2013-1748
Abstract 1751: The E2F activators signal centrosome amplification in breast cancer cells through centrosome regulatory molecules.
Authors: Lee Mi-Young , Saavedra Harold Ivan 
Published: August 2014

Abstract
Based on the elevated frequencies of centrosome amplification in premalignant breast lesions and in breast tumors, centrosome amplification is proposed to play a role in breast tumorigenesis. The coordination between cell and centrosome cycles is of paramount importance to maintain genomic stability and to the prevention of mammary tumorigenesis. Thus, both cell cycle regulators and molecules that regulate centrosome duplication work together to prevent abnormal centrosome duplication. E2Fs are transcription factors that regulate various cellular processes, such as DNA replication, DNA repair, cell proliferation and apoptosis; their role on centrosomal and mitotic regulation is understood poorly. We hypothesize that the E2F activators (E2F1, E2F2, E2F3a) play key roles in regulating centrosome amplification in HER2 positive breast cancer cells. We found that the E2Fs activators are deregulated or overexpressed in HER2 positive breast cancer cells displaying centrosome amplification, since serum withdrawal does not downregulate the E2F activators (which occurs in control MCF10A cells upon serum-withdrawal). Upregulated E2Fs correlated with the transcriptional overexpression of cell cycle and centrosome regulatory targets, including cylin D, cyclin E, Nek2 and Plk4. Knockdown of E2Fs in HER2 positive cells decreased centrosome amplification without affecting the cell cycle, or entry into S phase. The chromatin immunoprecipitation (ChIP) assay showed binding of E2F1, E2F2 and E2F3 into the promoter of Nek2 and between exons 1 and 2 of Plk4. In two out of three of the Her2+ breast cancer cell lines displaying centrosome amplification, extinguishing E2F expression leads to downregulation of Nek2 and cyclin D1 -potent inducers of centrosome amplification-. In conclusion, centrosome amplification in Her2+ breast cancer cells is dependent on the E2Fs activators and is mediated by molecules that play critical roles in centrosome duplication. We have identified a novel mechanism where E2F-generated centrosome amplification may contribute to breast carcinogenesis.
Citation Format: Mi-Young Lee, Harold Ivan Saavedra. The E2F activators signal centrosome amplification in breast cancer cells through centrosome regulatory molecules. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1751. doi:10.1158/1538-7445.AM2013-1751
Abstract 1753: KPNA7, a nuclear transport receptor, promotes malignant properties of pancreatic cancer cells in vitro.
Authors: Rauhala Hanna E. , Laurila Eeva , Vuorinen Elisa , Savinainen Kimmo , Kallioniemi Anne 
Published: August 2014

Abstract
Pancreatic cancer is an aggressive malignancy and one of the leading causes of cancer deaths. The high mortality rate is mostly due to the lack of appropriate tools for the early detection of the disease and a shortage of effective therapies. We have previously shown that karyopherin alpha 7 (KPNA7) is frequently amplified and overexpressed in pancreatic cancer. KPNA7 is a recently characterized member of the alpha karyopherin family of nuclear import receptors. The nuclear import machinery is composed of a complex network of proteins required for the appropriate transport of proteins from the cytoplasm to the nucleus. Abnormal function of this machinery leads to incorrect localization of nuclear proteins and disturbances in cellular homeostasis, which may subsequently contribute to the development of various diseases including cancer. Indeed, previous evidence has linked members of the karyopherin alpha family, especially KPNA2, to cancer pathogenesis.
In this study we demonstrate that KPNA7 expression is absent in practically all normal human adult tissues but elevated in several pancreatic cancer cell lines as well as in some other cancer types. Inhibition of KPNA7 expression in AsPC-1 and Hs700T pancreatic cancer cells led to a striking reduction in cell growth due to the induction of the cell cycle regulator p21 and subsequent G1 arrest of the cell cycle. In both of these cell lines KPNA7 silencing also resulted in decreased anchorage independent growth, and additionally in the AsPC-1 cells reduced cell migration and invasion. Furthermore, in the Hs700T cells KPNA7 silencing resulted in dramatic morphological change where the cells acquired fibroblast-like shape. This phenotypic change was not explained by induction of EMT or senescence.
In conclusion, our data strongly demonstrate that KPNA7 silencing inhibits the malignant properties of pancreatic cancer cells in vitro and thereby provide the first evidence on the functional role of KPNA7 in human cancer. Moreover, the lack of KPNA7 expression in normal adult tissues highlights it as a potential novel therapeutic target for cancer. Further studies are needed to identify the cargo proteins transported by KPNA7. These studies are likely to reveal important new information on nuclear transport and may highlight the molecular mechanisms involved in KPNA7 mediated phenotypes in cancer cells.
Citation Format: Hanna E. Rauhala, Eeva Laurila, Elisa Vuorinen, Kimmo Savinainen, Anne Kallioniemi. KPNA7, a nuclear transport receptor, promotes malignant properties of pancreatic cancer cells in vitro. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1753. doi:10.1158/1538-7445.AM2013-1753
Abstract 1755: Invasive cancer cells are mostly in the G0/G1 phase of the cell cycle.
Authors: Yano Shuya , Mii Sumiyuki , Tome Yasunori , Hiroshima Yukihiko , Uehara Fuminari , Miwa Shinji , Fujiwara Toshiyoshi , Hoffman Robert M. 
Published: August 2014

Abstract
Invasive cancer cells are a critical target for chemotherapy. However, the cell cycle phase of invasive cancer cells is poorly understood. Cancer cells were cultured in 3D Gelfoam® culture where they have in vivo-like cell cycle kinetics. Cancer cell-cycle kinetics were visualized using a fluorescence ubiquitination cell cycle indicator (FUCCI), whereby quiescent cancer cells express mKusabira-Orange fluorescent protein (red) and proliferating cells express mAzami-Green fluorescent protein (green). Real-time imaging demonstrated that cancer cells in the G0/G1 phase are invasive and disseminate in Gelfoam histoculture. Moreover, in vivo, FUCCI-expressing cancer cells were in G0/G1 phase when they metastasized to the liver. Disseminated cancer cells in the peritoneal cavity were also in G0/G1 phase. Most drugs currently in use target cells in S/G2/M are therefore may not be able to target invasive cancer cells. Color-coded cell-cycle imaging of cancer cell invasion should provide a novel platform for the rapid screening of candidate therapeutic agents against quiescent, invasive cancer cells.
Citation Format: Shuya Yano, Sumiyuki Mii, Yasunori Tome, Yukihiko Hiroshima, Fuminari Uehara, Shinji Miwa, Toshiyoshi Fujiwara, Robert M. Hoffman. Invasive cancer cells are mostly in the G0/G1 phase of the cell cycle. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1755. doi:10.1158/1538-7445.AM2013-1755
Abstract 1758: Cancer cell location in tumor determines cell cycle position and dormancy.
Authors: Yano Shuya , Tome Yasunori , Digman Michelle , Momiyama Masashi , Suetsugu Atsushi , Gratton Enrico , Hoffman Robert M. 
Published: August 2014

Abstract
The phase of the cell cycle can determine whether a cancer cell can respond to most drugs. The fluorescence ubiquitination cell cycle indicator (FUCCI) was used to image the cell cycle phase within tumors. In nascent tumors in nude mice, approximately 30% of the cells in the center of the tumor were in G0/G1 and 70% in S/G2/M. In contrast, approximately 90% of cancer cells in the center of an established tumor were in G0/G1 phase. Similarly, approximately 75% of cancer cells far from (&gt;100 μm) tumor vessels were in G0/G1. Although 60-70% of cancer cells near the surface of an established tumor (&lt; 100 μm) or near blood vessels were in S/G2/M, these cells are a small minority of an established tumor. Moreover, tumors that are stable in size for more than six months in nude mice consisted of mostly G0/G1 cells, suggesting they are dormant. The results presented here have profound implications for cancer therapy, since most drugs currently in use target cells in S/G2/M, which are a minor fraction in an established tumor. With the developments reported here, drugs that target non-dividing and dormant cancer cells can be readily identified.
Citation Format: Shuya Yano, Yasunori Tome, Michelle Digman, Masashi Momiyama, Atsushi Suetsugu, Enrico Gratton, Robert M. Hoffman. Cancer cell location in tumor determines cell cycle position and dormancy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1758. doi:10.1158/1538-7445.AM2013-1758