bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1808: HM-032, a novel PI3K/mTOR dual inhibitor, is active on K-Ras/Raf mutation tumors through up-regulation of Bim
Authors: Cui Yumin , Zhang Weihan , Ren Yongxin , Guo Mingchuan , Long Jingwen , Zhou Enkun , Sai Yang , Wang Jian , Yan James , Li Jia , Qing Weiguo , Su Weiguo 
Published: August 2012

Abstract
PIK3CA gene amplification and mutations have been identified in many types of tumors, suggesting the deregulation of PI3K/AKT/mTOR axis plays pivotal roles in tumorigenesis and development. K-Ras/Raf mutation is recognized as one of the key drug resistant factors for tumors against TKIs. HM-032 was reported here as a potent, selective and reversible ATP-competitive PI3K/mTOR dual inhibitor with special apoptotic activity in tumor cells harboring K-Ras mutations. HM-032 showed potent kinase inhibition with IC50 of 0.0008, 0.002, 0.001, 0.002 and 0.001 µM on PI3Kα, β, δ, ≤ and mTOR, respectively. In human prostate PC3 cells, it inhibited p-AKTS473, p-S6 and p-4EPB1 with IC50s of 0.002, 0.015 and 0.056 μM. Of the 89 tumor cell lines from lung, colon, breast, ovarian, and other tumor types, it was found that tumor cells with HER2 gene amplification, or PIK3CA mutation were relatively more sensitive to HM-032. Attractively, HM-032 showed apoptotic induction activity in the tumor cells harboring Ras/Raf mutations through inhibiting p-Erk and increasing gene expression of pro-apoptotic protein Bim. This result suggested that HM-032 might bring benefits to patients carrying K-Ras/Raf mutations in the clinic. Consistent with in vitro studies, HM-032 exhibited significant tumor growth inhibition in a dose dependent manner on multiple human xenograft models, including breast tumor MDA-MB-361(PIK3CAE545K, Her2 amplification), lung tumors H460 (PIK3CAE545K, K-RasQ61H) and A549 (LKB1 del, K-RasG12S), and glioblastoma U87MG (PTEN del) after 3 weeks oral dosing. Correspondingly, decrease of p-AKT and p-S6 was observed in the tumor xenograft tissues upon treatment with HM-032. In addition, HM-032 exhibited unique in vivo PK properties characterized by low clearance and long t1/2, which supported the intermittent dosing schedule in xenograft models. Based on the pre-clinical study results, HM-032 is anticipated to be a promising agent against solid tumors including carrying Ras/Raf mutations.
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 1808. doi:1538-7445.AM2012-1808
Abstract 1810: Mechanistic studies of the dual Akt and JNK inhibitor Chaetoglobosin K: Effect on downstream pathways and AP-1 proteins in tumorigenic cells
Authors: Ali Amna , Matesic Diane F. 
Published: August 2012

Abstract
We have previously shown that the anti-tumorigenic indolylcytochalasin Chaetoglobosin K (ChK) concomitantly down-regulates Akt and JNK activation in ras-transformed cells. This dual inhibition was found not be regulated by Rac1, a Rho protein that is involved in both signaling pathways, or MKK4, an upstream kinase of JNK. The purpose of this study was to determine: 1) the effect of ChK on the activation of downstream mediators of the PI3K/Akt (including mdm2), and JNK (including the activator protein-1 (AP-1) proteins and stat3) signaling pathways; 2) whether the upstream mitogen-activated protein kinase kinase 7 (MKK7) is involved in ChK's effect on JNK. The AP-1 transcription factor complex, composed of proteins of the JUN, FOS, and ATF families, has become a promising therapeutic target due to the proposed role of AP-1 activation in tumorigenesis. In these studies, ras-transformed rat liver epithelial cells were grown to confluence and treated with either ChK (5μM or 10μM) or vehicle (DMSO) for 24 hours. Cell proteins were extracted and separated using SDS-PAGE. Western blot analysis was performed using phosphorylation site-specific antibodies to monitor changes in MKK7, c-JUN, ATF-2, mdm2, and stat3 protein activation levels. The results of these studies indicate that ChK treatment decreased c-JUN and ATF-2 phosphorylation, but had no effect on stat3 phosphorylation. Additionally, ChK treatment decreased mdm2 phosphorylation. ChK did not alter MKK7 activation levels and, taking into consideration its lack of effect on MKK4, suggest ChK does not inhibit JNK via its archetypical MAPK signaling pathway. These studies indicate ChK may serve as a small molecule inhibitor of the AP-1 pathway proteins, as well as the Akt/mdm2 pathway. This data further supports ChK's potential as a unique targeted tumor therapy. This project was funded by NIH grant 1R15CA135415
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 1810. doi:1538-7445.AM2012-1810
Abstract 1822: Novel potent inhibitor of Bcr-Abl mutated imatinib resistant chronic myeloid leukemia cell lines
Authors: Joshi Kalpana S. , Manohar Sonal , Jalota-Badhwar Archana , Sonawane Vinay , Damre Anagha , Sivakumar Meenakshi , Sharma Somesh 
Published: August 2012

Abstract
The hallmark of chronic myeloid leukemia (CML) is the presence of Bcr-Abl oncoprotein that is essential for leukemogenesis and accumulation of neoplastic cells. The Abl tyrosine kinase inhibitor imatinib mesylate (Gleevec) represents the standard treatment for CML. However, a number of CML patients develop imatinib resistance and several mechanisms of resistance have been described. While most mutant forms are sensitive to second-generation tyrosine kinase inhibitors, the T315I mutation remains completely refractory to imatinib, as well as to these agents. Treatment of CML patients harboring T315I mutation is still an unmet medical need in the imatinib and post-imatinib era. We have identified P2745, a novel orally bioavailable small molecule that is effective in imatinib resistant mutations and particularly T315I mutation form to address this unmet medical need. In vitro P2745 showed potent cytotoxicity (IC50 0.8-5 μM) in twelve Bcr-Abl mutated imatinib resistant cell lines including T315I compared to wild type Bcr-Abl cell lines. P2745 did not show cytotoxicity upto 30 μM in normal fibroblasts (MRC-5 and WI-38) and normal human peripheral blood mononuclear cells thus indicating specificity towards cancerous cells. P2745 inhibited pCrkLTyr207 in imatinib-resistant CML cell lines accompanied with down regulation of Bcr-Abl protein levels. Additionally, it up regulated tumor suppressor protein SMAR-1 which resulted in negative regulation TGF-β/SMAD-dependent pathway as demonstrated by low phosphorylated levels of SMAD2 and SMAD3, two key players implicated in the preservation of the malignant progenitor population, and partly responsible for the resistance to treatments targeting Bcr-Abl. P2745 also induced significant apoptosis in imatinib resistant cell lines (Y253F, T315I and E255V) but not in normal MRC-5 cell line. In addition, like imatinib it induced 80-90 % apoptosis in cells derived from CML patients. In vivo studies demonstrated significant (p&lt;0.001), dose dependent efficacy in imatinib resistant T315I cells xenograft in SCID mice. It also demonstrated significant in vivo efficacy in Bcr-Abl wild type imatinib sensitive K-562 (p&lt;0.05) and Ba/F3 (p&lt;0.001) xenografts in SCID mice. PK-PD evaluation in imatinib resistant xenograft experiments indicated that at the efficacious dose, P2745 modulated proteins responsible for CML pathogenesis (60-80 %), which correlates with the levels of P2745 in the tumors. This unique mechanism of action makes P2745 a promising clinical candidate for CML patients harboring T315I mutation.
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 1822. doi:1538-7445.AM2012-1822
Abstract 1834: Targeting ABC transporters in cancer through small molecule inhibitors
Authors: Huynh Tony , Tivnan Amanda , Munoz Marcia , Cheung Leanna , Vishvanath Anasuya , Flemming Claudia , Watt Fujiko , Burkhart Catherine , Gudkov Andrei , Fletcher Jamie , Henderson Michelle , Norris Murray , Haber Michelle 
Published: August 2012

Abstract
Multidrug resistance is one of the major causes of treatment failure in cancer therapy. While multidrug transporter proteins are known for their contributions to chemoresistance and efflux of anti-cancer drugs from cancer cells, a significant body of evidence points to their fundamental roles in tumour biology (Fletcher et al, Nature Rev Cancer, 10:147-156, 2010). We have investigated the ABCC subfamily of multidrug transporter genes in the highly malignant and aggressive childhood solid tumour, neuroblastoma and found that high levels of ABCC1 and ABCC4 are powerful independent prognostic indicators of clinical outcome. However, the agents used to treat the patients described in these studies are not known substrates of ABCC4 and we have shown that siRNA-mediated knockdown of ABCC4 results in reduced proliferation and enhanced morphological differentiation of neuroblastoma cells, in the absence of any cytotoxic drug treatment (Henderson et al, JNCI, 103;1-16, 2011). The aim of this study is to develop a potential new approach for the treatment of neuroblastoma through the inhibition of ABCC4 using small molecule inhibitors. A cell-based screen of a library of diverse chemical small molecules was used to isolate potent small molecule inhibitors of ABCC4 that were able to sensitize HEK293 cells over-expressing MRP4 to a cytotoxic MRP4 substrate, 6-mercaptopurine (6MP). Filtering of compounds based upon their ability to cause 6MP accumulation, together with focused library screening, have resulted in the identification of several chemical structures able to specifically block MRP4. In addition to reversing drug resistance to 6MP, these compounds cause morphological differentiation and inhibition of cell growth, as seen with MRP4 siRNA, in the BE2C neuroblastoma cell line. Importantly, these compounds significantly potentiate morphological differentiation caused by the established differentiation agent, all-trans retinoic acid. We further show that these inhibitors have potency in other MRP4 expressing cancer cell lines beyond neuroblastoma. These pharmacological inhibitors offer clinical potential for the treatment of neuroblastoma and other MRP4 overexpressing cancers.
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 1834. doi:1538-7445.AM2012-1834
Abstract 1838: Efficacy of ribonuclease QBI-139 in combination with standard of care therapies
Authors: Strong Laura E. , Kink John A. , Pensinger Daniel , Mei Baigen , Shahan Mark , Raines Ronald T. 
Published: August 2012

Abstract
RNA has been recognized as a drug target for cancer therapy, as evidenced by the ongoing clinical trials of RNAi and antisense therapies. An alternative approach that circumvents the delivery and stability issues of those drugs is to harness the activity of naturally occurring RNA degradation enzymes. Human ribonuclease (RNase) variants have been generated with diminished binding to their natural inhibitor inside cells, which allows the new proteins to kill cancer cells. One of these RNase variants, referred to as QBI-139, demonstrated efficacy against multiple tumor types in xenograft models of human cancer and was selected for an ongoing first in human Phase I clinical trial. Non-small cell lung and ovarian cancer are two of the indications where QBI-139 has shown significant efficacy as a single agent in xenograft models. In planning for the next stage of clinical trials, the impact of combinations of QBI-139 plus standard of care agents in these diseases was determined both in vitro and in vivo. QBI-139 showed additive and synergistic activity in combination with cisplatin and docetaxel, which are standard of care for non-small cell lung and ovarian cancer, respectively. Fixed ratios of QBI-139 and the combination drug based on their EC50 values were tested. The Combination Index (CI) was determined using median effect analysis. Synergy was demonstrated with QBI-139 in combination with cisplatin against non-small cell lung cancer (A549 and H1975). An additive effect of QBI-139 and cisplatin was seen in ovarian (Ovcar-3) cancer. In ovarian cancer (SK-OV-3), a combination of docetaxel and QBI-139 was synergistic with QBI-139. The benefit of the combinations were repeated in xenograft models of both cancers and were signifcat relative to each agent alone. Non-small cell lung and ovarian cancer represent critical unmet needs and new, differentiated treatment approaches such as QBI-139 combination therapy are critical.
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 1838. doi:1538-7445.AM2012-1838
Abstract 1839: Phosphodiesterase 4 regulates lung tumor growth through HIF regulation, proliferation, and angiogenesis
Authors: Savai Rajkumar , Pullamsetti Soni Savai , Schmall Anja , Pomagruk Dawid , Hänze Jörg , Kolosionek Ewa , Wilhelm Jochen , Seeger Werner , Grimminger Friedrich , Schermuly Ralph Theo , Banat Gamal Andre 
Published: August 2012

Abstract
Lung cancer is the leading cause of cancer death worldwide. Recent data suggest that cyclic nucleotide phosphodiesterases (PDEs) are relevant in various cancer pathologies. Here, we elucidate the pathophysiological role of PDE4 and its therapeutic prospects in lung cancer. We exposed 10 different non-small cell lung cancer cell lines (adenocarcinoma, squamous, and large cell carcinoma) to hypoxia and assessed the expression and activity of PDE4 by quantitative real-time PCR, immunocytochemistry, western blotting, and PDE activity assays. Expression and activity of distinct PDE4 isoforms (PDE4A and PDE4D) increased in response to hypoxia in eight of the studied cell lines. Furthermore, we determined various potential hypoxia-responsive elements (HRE) in PDE4A and PDE4D. Silencing of hypoxia-inducible factor subunits (HIF1A and HIF2) by siRNA reduced hypoxic induction of PDE4A and PDE4D. Vice versa, using a PDE4 inhibitor (PDE4i), a cAMP-elevating agent, cAMP analogs, PKA activator/inhibitor, and EPAC activator, we demonstrated that PDE4-cAMP-PKA/EPAC axis regulates HIF signaling as measured by HRE reporter gene assay and expression of HIF target genes (LDHA, PDK1, VEGFA). Notably, PDE4i or PDE4A-/PDE4D-selective siRNA reduced human lung tumor cell proliferation in vitro and colony formation and altered the expression of cell-cycle regulators. Moreover, PDE4i treatment reduced hypoxia-induced VEGF secretion in human cells. In vivo, PDE4i inhibited tumor xenograft growth in athymic nude mice by altering proliferation and angiogenesis. Collectively, our findings suggest that PDE4 is overexpressed in lung cancer, exerts crosstalk with HIF pathways, and promotes lung cancer progression; thus, PDE4 may represent a therapeutic target for lung cancer therapy.
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 1839. doi:1538-7445.AM2012-1839
Abstract 1860: Protective effect of catechol-O-methyltransferase-mediated 4-hydroxyestradiol metabolism in human renal cell cancers
Authors: Chang Inik , Liu Jan , Majid Shahana , Saini Sharanjot , Zaman Mohd S. , Yamamura Soichiro , Shahryari Vary , Chiyomaru Takeshi , Deng Guoren , Dahiya Rajvir , Tanaka Yuichiro 
Published: August 2012

Abstract
Long-term exposure to estrogen and its metabolites may play an important role in renal cell carcinogenesis. Catechol-O-methyltransferase (COMT) participates in the estrogen metabolism pathway by neutralizing toxic substances. Although reduced COMT activity has been suggested to be a risk factor for estrogen-associated cancers, no studies have investigated the biological significance of COMT in the pathogenesis of human renal cell cancers (RCC). Using quantitative PCR, Western blotting and immunohistochemical staining, we initially found that COMT levels are significantly decreased in human RCC tissues and cells suggesting a suppressive role of COMT in tumor development. However, transient over-expression of COMT has no effect on the proliferation, apoptosis and cell cycle progression of RCC cell lines. In contrast, when cells over-expressing COMT are treated with its substrate 4-hydroxyestradiol (4-OHE2), growth is inhibited by apoptotic cell death. We also found that COMT over-expression combined with 4-OHE2 induces up-regulation of growth arrest- and DNA damage-inducible protein ≤ (GADD45α). We further show that down-regulation of GADD45α by a siRNA-mediated approach inhibits cell death, indicating the essential role of GADD45α in the underlying mechanism of COMT action in response to 4-OHE2. Finally, 4-methoxyestradiol (4-ME) fully reproduces the anti-proliferative function of COMT with 4-OHE2 by promoting GADD45α induction. Together, our study shows that COMT in the presence of 4-OHE2 prevents RCC cell proliferation by enhancing apoptosis, and that GADD45α plays a critical role in the COMT-mediated inhibition of RCC. These findings will provide new direction for the biomarker detection and corresponding treatment in the prevention of human RCC.
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 1860. doi:1538-7445.AM2012-1860
Abstract 1871: Role of CYP1B1 gene polymorphisms in anticancer drug cytotoxicity as studied on isogenic cell lines
Authors: Morvan Valérie Le , Richard Elodie , Bellott Ricardo , Pasquies Alban , Robert Jacques , Lansiaux Amélie 
Published: August 2012

Abstract
Cytochrome P450 1B1 (CYP1B1) is found in tumour tissue and is suspected to play a role in oncogenesis and drug resistance. CYP1B1 gene polymorphisms have been associated with the risk of developing lung and other cancers. We have recently shown that one of them (rs1056836, 1697C&gt;G, L432V) was significantly associated with the cytotoxicity of DNA-damaging anticancer drugs in two independent panels of tumour cell lines, the NCI-60 panel and the JFCR-45 panel (Mol Cancer Ther 2010; 9: 3315-21). The present study was aimed at identifying the molecular mechanisms involved in anticancer drug resistance associated with this polymorphic variation. We have cloned the wild-type human CYP1B1 cDNA (1697C) in a lentiviral vector pDesti-pGK and obtained the variant cDNA (1697G) by directed mutagenesis. The two polymorphic variants were then used for the generation of viruses and the infection of cell lines. The CYP1B1 viruses were produced by cotransfection of 293T cells with viral plasmid DNA and either pER51CYP1B1WT-pGK or pER51CYP1B1VAR-pGK plasmid DNA in the presence of calcium phosphate. Cell supernatants containing the virus were harvested 24 h after transfection, filtered through a 0.45 μm membrane and stored at −80°C. Five different cell lines devoid of CYP1B1 expression were infected (COS-1 [Fibroblastic cell line], SW620 [colorectal cancer cell line], CAL27, CAL33 and SQ20B [HNSCC cell lines]). We thus generated five pairs of isogenic cell lines differing only by the polymorphic status of one nucleotide in the CYP1B1 gene. mRNA and protein expression were evaluated by qRT-PCR and western blotting, respectively. The cytotoxicity of a panel of anticancer drugs was evaluated on these cell lines (cisplatin, oxaliplatin, gemcitabine, doxorubicin, etoposide, camptothecin, irinotecan and its active metabolite [SN38]). A systematically higher IC50 was noticed for the cell lines harbouring the variant cDNA as compared to those harbouring the wild-type cDNA, the variant cell lines being 2-3-fold resistant to all agents. These results obtained on isogenic cell lines were in perfect agreement with what could be expected from the study of the cell line panels. The catalytic activity of the two CYP1B1 variants is being studied using ethoxyresorufine O-deethylation. A population of 125 head-and-neck cancer patients treated by chemotherapy in the palliative setting has been prospectively constituted and will be used for the clinical validation of the interest of CYP1B1 genotyping for predicting anticancer drug activity.
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 1871. doi:1538-7445.AM2012-1871