bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2932: Role of P53 in the negative regulatory function of PIAS3 with STAT3 in lung cancer
Authors: Dabir Snehal , Kluge Amy , Dowlati Afshin 
Published: June 2012

Abstract
Constitutive activation of Signal Transducers and Activators of Transcription 3 (STAT3) and p53 mutations both play an important role in lung cancer pathogenesis. We have demonstrated a negative inhibitory role of Protein Inhibitor of Activated STAT3 (PIAS3) in STAT3 signaling (Kluge et al 2009 and Dabir et al. 2009) in lung cancer. Recent data suggests that p53 plays a role in oncogenic STAT3 signaling. We sought to determine the biochemical interaction between PIAS3, STAT3 and p53 at both protein and DNA levels in p53 wild-type (A549 and H1666), mutant (Calu1) and p53 null (H358) non-small cell lung cancer (NSCLC) lines. We demonstrate that PIAS3 binds to STAT3 under Epidermal Growth Factor (EGF) stimulation in p53 WT cell lines but not so significantly in p53 mutant cell lines. ChIP studies with PIAS3 antibody showed p53/PIAS3 binding to DNA under EGF stimulation. We observed in vivo binding of PIAS3 to the promoter region of RNSP1 (target of p53) in A549 (p53 WT) cells by Promoter Tiling Array. Our initial data suggests that PIAS3 negative regulatory effect on STAT3 is more prominent in p53 WT cells. Indeed, transfection of WT cells with a PIAS3 construct results in a significant decrease in STAT3 transcriptional activity in all cells but more significantly in WT cells. Knockdown of p53 using sh-p53 lentivirus construct tagged with GFP in p53 WT cells shows that it partially negates the effects of PIAS3 on STAT3 suggesting at least a partial requirement of WT p53 for full PIAS3 effects on STAT3 signaling. However our data suggests that PIAS3 induces apoptosis as demonstrated by TUNEL assay and changes of Bcl2 family members irrespective of p53 status suggesting that its growth inhibitory effects are p53 independent.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2932. doi:10.1158/1538-7445.AM2011-2932
Abstract 2936: MicroRNA-205 interdiction of Src-mediated oncogenic pathways in renal cancer
Authors: Majid Shahana , Dar Altaf A. , Saini Sharanjot , Hirata Hiroshi , Shahryari Varahram , Tanaka Yuichiro , Yamamura Soichiro , Ueno Koji , Zaman Mohd Saif , Singh Kamaldeep , Chang Inik , Deng Guoren , Carroll Peter R. , Dahiya Rajvir 
Published: June 2012

Abstract
Introduction and Objective: The Src family of protein kinases (SFKs) plays key roles in regulating fundamental cellular processes, including cell growth, differentiation, cell shape, migration and survival, and specialized cell signals in various malignancies. The pleotropic functions of SFKs in cancer make them promising targets for intervention. We investigated the role of miR-205 in inhibition of Src-mediated oncogenic pathways in renal cancer.
Methods: The methods employed in this study include quantitative-real time PCR; western blot; fluorescence-activated cell sorting assays for cell cycle distribution and apoptosis; assays for cell viabiltity, clonability, migration and invasiveness of prostate cancer cells. Luciferase reporter and mutational assays; generation of miR-205 stable cells and in-vivo study in nude mice was also performed.
Results: The expression of miR-205 was significantly suppressed in renal cancer cell lines and tumors when compared with normal tissues and a non-malignant cell line, and is correlated inversely with the expression of SFKs. miR-205 significantly suppressed the luciferase activity of reporter plasmids containing the 3’UTR sequences complementary to either Src, Lyn or Yes, which was abolished by mutations in these 3’UTR regions. Over-expression of miR-205 in A498 cells reduced Src, Lyn and Yes expression both at mRNA and protein levels. Proliferation of renal cancer cells was suppressed by miR-205, mediated by the phosphoSrc-regulated ERK1/2 pathway. Cell motility factor- FAK and STAT3 activation was also inhibited by miR-205. Transient as well as stable over-expression of miR-205 in A498 cells resulted in induction of G0/G1 cell cycle arrest and apoptosis as indicated by decreased levels of cyclin D1 and cMyc, suppressed cell proliferation, colony formation, migration, and invasion in renal cancer cells. miR-205 also inhibited tumor cell growth in vivo. This is the first study demonstrating that miRNA-205 inhibits proto-oncogenic Src family of kinases indicating a therapeutic potential of miR-205 in the treatment of renal cancer.
Conclusion: This study demonstrates that miRNA-205 inhibits proto-oncogenic Src family of kinases indicating a therapeutic potential of miR-205 in the treatment of renal cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2936. doi:10.1158/1538-7445.AM2011-2936
Abstract 2939: Chk1 inhibition and Wee1 inhibition combine synergistically to inhibit cellular proliferation
Authors: Davies Kurtis D. , Sullivan Francis , von Carlowitz Ira , Huerou Yvan Le , Wallace Eli , Woessner Richard D. , Gross Stefan 
Published: June 2012

Abstract
Inhibition of the checkpoint kinase Chk1, both as a monotherapy and in combination with DNA damaging cytotoxics, is a promising therapeutic strategy for human cancer. However, much remains to be learned in regard to the patient populations that will respond best to a Chk1 inhibitor and the optimal therapeutics to combine with a Chk1 inhibitor. In an effort to discover sensitizing mutations and novel combination strategies for Chk1 inhibition, we performed a synthetic lethality siRNA screen with the selective Chk1 inhibitor Chk1-A. This screen employed a custom made library of siRNAs against 197 genes (3 siRNAs per gene), most of which are involved in cell-cycle control or DNA damage repair. One of the most prominent and consistent hits across runs of the screen performed in PC3, LNCaP, and A549 cell lines was Wee1 kinase. MK-1775 is a small molecule inhibitor of Wee1 that is currently in early stage clinical trials. In confirmation of the results obtained from the siRNA screen, we found that Chk1-A and MK-1775 synergistically inhibited proliferation in multiple cell types. The combination of the two molecules resulted in up to a 5-fold enhancement of anti-proliferative activity compared to what would be expected from pure additivity. This anti-proliferative synergy correlated with a synergistic induction of apoptosis. We explored the mechanism of the impressive synergy by examining the cellular and biochemical effects of the Chk1-A and MK-1775 combination. We found that co-treatment with the two inhibitors resulted in dramatic decreases in inhibitory phosphorylation of cyclin-dependent kinases 1 and 2, increases in DNA damage, and the collapse of DNA replication. In conclusion, the combination of a Chk1 inhibitor and a Wee1 inhibitor may be an effective treatment strategy for cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2939. doi:10.1158/1538-7445.AM2011-2939
Abstract 2943: Targeting the E2F pathway in cancer chemotherapeutics
Authors: Kurtyka Courtney A. , Ma Yihong , Bian Haikuo , Cubitt Christopher , Law Brian , Corsino Patrick , Cress W. Douglas 
Published: June 2012

Abstract
HLM006474 is a recently identified small molecule E2F inhibitor. Since E2F is known to drive expression of genes required for cell cycle progression, it is predicted that blocking the E2F pathway will slow proliferation and have anticancer activity. Microarray analysis demonstrates that HLM006474 treatment results in profound changes in the expression of genes involved in cell cycle progression and nucleotide biosynthesis. Flow cytometry reveals that treatment of A375 cells results in a cell cycle arrest, primarily in G2/M. As would be expected, cell lines deficient in Rb are more sensitive to E2F inhibition than are syngeneic lines expressing Rb. HLM006474 reduces the proliferation of a broad array of cell lines with a biological IC50 that varies between 5 and 70 μM. Combination of HLM006474 with common chemotherapeutic agents cisplatin and gemcitabine demonstrate little synergy; however HLM006474 synergizes with paclitaxel and a novel cdk inhibitor NSC11702. Interestingly, we discovered that paclitaxel sensitivity inversely correlated with E2F4 levels in a series of non-small cell lung cancer (NSCLC) lines, suggesting that synergy between HLM006474 and paclitaxel is due to HLM006474's inhibition of E2F4 activity and expression. To test this, H1299 cells which have high E2F4 levels and a high paclitaxel IC50 were depleted of E2F4 with siRNA and the IC50 determined. Taken together, these results suggest that HLM006474 may have efficacy against cancers in which E2F is deregulated and may be useful in combination with other drugs that target cell cycle components.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2943. doi:10.1158/1538-7445.AM2011-2943
Abstract 295: Detection of hypomethylation of LINE1 on peripheral white blood cells and plasma DNA in US hepatocellular carcinoma patients
Authors: Zhang Yujing , Delgado-Cruzata Lissette , Wu Hui-Chen , Gamble Mary , Wang Qiao , Regina Santella M. , Siegel Abby B. 
Published: June 2012

Abstract
Hepatocellular carcinoma (HCC) is one of the most common cancers in the world and is increasing in the United States. Epigenetic changes, including genomic DNA hypomethylation, have been implicated in cancer development by inducing chromosomal instability. In the present study, methylation of long interspersed nucleotide element-1(LINE1), a surrogate marker of global hypomethylation, in peripheral white blood cells and plasma DNA in 47 US HCC patients was detected by pyrosequencing. Correlations between LINE1 methylation, and clinical data and other biomarkers were also analyzed. Methylation of LINE1 in WBC DNA is statistically significantly correlated with that in plasma DNA (R=0.32, p=0.04). WBC DNA global hypomethylation was significantly decreased in subjects with hepatitis C (HCV) infection (p=0.05). Plasma folate levels were not correlated with plasma DNA LINE1 methylation (R=0.13, p=0.41) or with WBC LINE1 methylation (R=−0.19, p=0.24). However, WBC folate levels were statistically significantly associated with patients’ survival. HCC patients who survived at least 3 months after diagnosis had lower WBC folate compared to patients who died within 3 months (p=0.004). We are currently expanding the HCC cohort and also analyzing biomarkers of chemical exposure (polycyclic aromatic hydrocarbons and aflatoxin B1) to investigate associations with methylation changes.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 295. doi:10.1158/1538-7445.AM2011-295
Abstract 2951: Regulation of E2F-dependent transcription by the mTORC1 pathway
Authors: Law Brian K. , Corsino Pat E. , Law Mary E. , Jahn Stephan , Davis Bradley 
Published: June 2012

Abstract
mTORC1 inhibitors such as rapamycin and its analogs (rapalogs) are promising anticancer agents, which are effective against some tumors, yet ineffective against others. Understanding the mechanisms controlling tumor responsiveness or resistance to rapalogs is therefore critical. Much of the anticancer activity of mTORC1 inhibitors stems from inhibition of cancer cell proliferation and suppression of the endothelial cell proliferation required for angiogenesis. Rapalogs induce a G1 cell cycle arrest, which has been attributed to suppression of the translation of proliferation-associated proteins. However the exact mechanism by which mTORC1 inhibition results in G1 cell cycle arrest is unclear.
Since activation of E2F-dependent transcription is required for the G1/S-phase cell cycle transition, we examined the mechanisms by which rapamycin inhibits the expression of E2F1, which is itself encoded by an E2F-dependent gene. Rapamycin treatment decreased the binding of Cdk2 to the E2F sites of the E2F1 promoter in DNA oligonucleotide affinity purification experiments. This observation was corroborated by a decrease in Cdk2 binding to E2F4, p130, and p107, and a corresponding increase in Cdk2 binding to p27 in coimmunoprecipitation experiments. This suggests a model in which Cdk2 is recruited to E2F sites of promoters by complex formation with E2F4, p130, and p107 and functions to relieve the repression of these elements by maintaining p130 and p107 in their hyperphosphorylated forms. Consistent with this model, rapamycin treatment decreased kinase activity associated with E2F-DNA binding elements, but had little effect on overall Cdk2 activity in crude cell lysates. Rapamycin caused disruption of Cdk2/p130-, p107-, E2F4-containing complexes on E2F promoter elements. These results provide insights into how rapamycin treatment inhibits E2F-dependent transcription. It is hoped that further analysis of Cdk2/p130/E2F complexes will reveal mechanisms of tumor resistance to rapalogs and opportunities for optimizing the efficacy of mTORC1 inhibitors using combination therapies.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2951. doi:10.1158/1538-7445.AM2011-2951
Abstract 2953: Involvement of HDAC11 in cell division cycle
Authors: Bagui Tapan K. , Sharma Savitha , Pledger W. J. 
Published: June 2012

Abstract
Histone deacetylases (HDACs) are a group of enzymes that catalyze removal of acetyl groups from a ε-N-acetyl lysine amino acid on histones. A number of non-histone proteins are also known to be deacetylated by these enzymes. Hence, these proteins are now also being referred to as lysine deacetylases (KDAC).
Based on function and DNA sequence similarity, HDAC proteins are classified in four groups; Class I, Class II, Class III and Class IV HDACs. HDAC11, the only member of Class IV HDAC, shows a DNA sequence similarity with both Class I and Class II HDACs.
In general, HDAC proteins are known as transcriptional inhibitors and are involved in cellular growth, development and apoptosis. Unlike other HDACs, function of HDAC11 is not widely studied. Although this enzyme is reported as a transcriptional inhibitor, little is known about its role in connection to cell division cycle or cell density. Analysis of our microarray data shows that Balb/C 3T3 cells, stimulated with PDGF and plasma, contain considerably reduced level of HDAC11 transcript compared to that in the quiescent Balb/C 3T3 cells. The protein level under similar conditions mimics the pattern of transcript level. These results indicate that as cells leave quiescence state HDAC11 expression is down-regulated or may be reduction of HDAC11 expression causes quiescent cells to enter cell cycle. It may also be possible that cell-cell contact inhibition positively regulates HDAC11 expression and as the cell grows in presence of PDGF and plasma, the contact inhibitory property is lost which in turn causes the reduction of the protein expression. Further work is in progress to elucidate the role of HDAC11 with respect to cell cycle regulation or cell density.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2953. doi:10.1158/1538-7445.AM2011-2953
Abstract 2972: In vitro quantification and modeling of DNA damage by histone H2A after exposure to gemcitabine and a Chk1 inhibitor
Authors: Kang Xiaolin , Kindt Erick , Yamazaki Shinji , Troche Gabriel E. , Spilker Mary E. 
Published: June 2012

Abstract
Background: Gemcitabine is a nucleoside analog used as an anti-cancer chemotherapeutic drug. To enhance its disruption of DNA replication and repair, Chk1 inhibitors are being developed for use in combination with Gemcitabine and other cytotoxic agents. Evaluation of these therapies with mechanistic biomarkers can be an important part of the drug development process. One such biomarker is the phosphorylation of histone H2A (γH2AX), which is a DNA damage response biomarker. An ELISA based assay has been developed to quantify γH2AX. This quantitative assay provides data that is incorporated into a mathematical model relating drug exposure to DNA damage and cell viability.
Experiment Design: MiaPaCa-2 cells, a human pancreatic tumor cell line, were subjected to Gemcitabine alone (0.1 to 5uM for 2 hours), a Chk1 inhibitor alone (0.1-5uM for 2 – 48 hours), or the Chk1 inhibitor in combination with 0.5 and 5uM Gemcitabine. Cellular concentrations of Gemcitabine and the Chk1 inhibitor were detected with LC/MS. DNA damage was assessed by the γH2AX ELISA at 2, 6, 24 and 48 hours after the start of incubation with drug. In addition to γH2AX, cell viability was measured by cell number at 48 hours. A mathematical model was developed to quantify the modulation of γH2AX when exposed to each drug separately and in combination.
Result: Transient exposure of the cells to Gemcitabine resulted in an increase in γH2AX at later times (24 and 48 hours). The Chk1 inhibitor resulted in a dose dependent increase in γH2AX, with a greater effect being observed at later times of exposure. The combination therapy showed a greater response than Gemcitabine or Chk1 alone. However it was observed that higher doses of Gemcitabine and Chk1 in combination did not always yield the largest γH2AX response or the greatest effect on cell viability. This may be due to cellular resistance and is still being investigated.
Conclusion: The ELISA based assay for γH2AX provides a quantitative assessment of the level of DNA damage. This information can then be utilized in developing mathematical models of drug action alone and in combination with other drugs.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2972. doi:10.1158/1538-7445.AM2011-2972
Abstract 2982: Impact of the RB-pathway in breast cancer heterogeneity and therapeutic response
Authors: McClendon A. Kathleen , Ertel Adam , Dean Jeffry , Thangavel Chellappagounder , Knudsen Karen E. , Witkiewicz Agnes K. , Knudsen Erik S. 
Published: June 2012

Abstract
Molecular heterogeneity in breast cancer is associated with differential prognosis and response to therapy. However, in spite of extensive molecular classification, pathways that can be specifically targeted to understand the basis of disease and improve treatment remain poorly understood within specific subtypes of breast cancer. The retinoblastoma tumor suppressor (RB) pathway is deregulated in most cancers; however varied mechanisms of inactivation have significant impacts on tumor biology. Here novel mechanistic and preclinical models were combined with analyses of tumor specimens to decipher the differential impact of the RB-pathway within breast cancer subtypes and as a specific target for patient stratification and therapeutic targeting.
Initial gene expression datasets encompassing over 2000 breast cancer patient samples were used to demonstrate a striking dichotomy in the mechanisms of RB functional inactivation within subtypes of disease. In ER-positive breast cancer, disruption of RB-pathway function was associated with poor prognosis and failure of endocrine therapy. Functional studies demonstrate that such therapeutic failure largely occurs in the presence of an intact Rb gene, as a result of deregulated mitogenic signaling. In such models of hormone refractory disease we demonstrate that pharmacological activation of RB is a potent second-line therapy. In contrast, in ER-negative tumor populations RB inactivation occurs in 40-50% of cases. This event yields complete loss of RB protein, as occurs through genetic and epigenetic mechanisms. Strikingly, in ER-negative disease RB loss is associated with improved response to chemotherapy and longer relapse-free survival. The basis for improved response involves both deregulation of cell cycle checkpoints and apoptotic processes. Ongoing analyses are using synthetic-lethal and combination-therapy approaches to rationally target RB-status in the management of breast cancer.
In total, these studies define a clear role for RB-pathway as a determinant of tumor heterogeneity in breast cancer that can be leveraged to more effectively treat breast cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2982. doi:10.1158/1538-7445.AM2011-2982
Abstract 2987: A critical role of translocated promoter region (Tpr) in chromosome segregation and cell division in cancer
Authors: Funasaka Tatsuyoshi , Nakano Hiroshi , Wong Richard 
Published: June 2012

Abstract
Cancer cells accumulate the many genetic abnormalities required for cancer development. Abnormal chromosome is often observed in cancer cells and is thought to be due to chromosome segregation errors during mitosis. In eukaryotic cells, the faithful segregation of daughter chromosomes during cell division depends on formation of a microtubule-based bipolar spindle apparatus. Nuclear pore complexes are massive multiprotein channels responsible for traffic between the nucleus and cytoplasm, and are composed of approximately 30 proteins termed nucleoporins. Several components of the nuclear pore complex/nucleoporins play critical roles in orchestrating the rapid remodeling events that occur during mitosis. Our recent studies revealed that the nucleoporin, Rae1, plays critical roles in maintaining spindle bipolarity. Here, we show association of another nucleoporin, termed Tpr (translocated promoter region), with the molecular motors dynein and dynactin, which both orchestrate with the spindle checkpoints Mad1 and Mad2 during cell division. Overexpression of Tpr enhanced multinucleated cell formation. RNA interference-mediated knockdown of Tpr caused a severe lagging chromosome phenotype and disrupted spindle checkpoint proteins expression and localization. Next, we performed a series of rescue and dominant negative experiments to confirm that Tpr orchestrates proper chromosome segregation through interaction with dynein light chain. Our data indicate that Tpr functions as a spatial and temporal regulator of spindle checkpoints, ensuring the efficient recruitment of checkpoint proteins to the molecular motor dynein to promote proper anaphase formation.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2987. doi:10.1158/1538-7445.AM2011-2987