bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract B26: Drug-Diagnostic co-development to target FLT3-ITD mutations in chemo-resistant acute myeloid leukemia cells
Authors: Ko Ching-Huai , Ting-Shou Chen , Mei-Wei Lin , Chin-Pen Lai , Wen-Hsun Kuo , Chrong-Shiong Hwang , Ling-Mei Wang , SC Tsai Jane 
Published: March 2013

Abstract
FMS-like tyrosine kinase-3 (FLT3) overexpression is the common phenomenon in acute myeloid leukemia (AML). There are two major types of FLT3 mutations: internal tandem duplication (ITD) and the activation-loop point mutation at 835th amino residue. Although these FLT3/ITD and the 835th point mutation only account for only 20–25% and 5–10% in AML patients, they have worse prognosis and are often resistant to conventional chemotherapy. Several drugs including CEP-701, MLN-518, and PKC-412 have been developed to target FLT3 tyrosine kinase activity in AML and have been evaluated in clinical trials and showed different efficacy towards these mutations. Therefore, identification of these mutations at the time of diagnosis during drug development, in the case of our drug candidate, BELK01260, will provide a better prognostic prediction, might guide the treatment selection and follow-up strategies. In the study, we developed a sensitive molecular assay with our drug candidate well-suited for this therapeutic need to detect FLT3 mutations and proposed to be used for future clinical application. 100 AML samples with at least 20 samples with known FLT3 mutations are collected and evaluated. The standardize procedure has met the requirement of clinical pathology laboratory with reasonable cost, and both the sensitivity and specificity of this technology achieve 99.9% compared with commonly used methods.
Abstract B28: Downregulation of vimentin confers resistance to the microtubule stabilizing agents peloruside A and laulimalide in 1A9 human ovarian carcinoma cells
Authors: Kanakkanthara Arun , Rawson Pisana , Northcote Peter T. , Miller John H. 
Published: March 2013

Abstract
Microtubule-targeting agents are an important class of drugs for the treatment of cancer. Although the development of drug resistance in cancer cells often limits the clinical efficacy of these agents, the mechanisms of resistance are not fully understood. Peloruside A (PLA) and laulimalide (LAU) are two marine sponge-derived stabilizing agents of microtubules. PLA and LAU represent the only known class of non-taxane site binding microtubule stabilizing agents and have a number of clinically useful potential advantages over paclitaxel, a widely used tubulin-targeting anticancer drug, including reduced susceptibility to the multidrug resistance P-glycoprotein efflux pump, good efficacy against taxane-resistant cells with mutations in the taxoid site, and more effective antitumor effects in non-small cell lung tumor xenografts. To understand the mechanisms of resistance to PLA and LAU, we used two drug-resistant sublines of the 1A9 human ovarian carcinoma cell line, R1 and L4. R1 cells are 6-fold resistant to PLA but remain fully sensitive to LAU; whereas, the L4 cells are 39-fold resistant to both PLA and LAU. We previously showed that both resistant cell lines exhibit different single point-mutations in their βI-tubulin gene. The L4 cells also have a high abundance of βII- and βIII-tubulin isotypes, which play a partial role in the resistance phenotype. To determine other protein changes that might contribute to the resistant phenotype of the R1 and L4 cells, we examined the proteome of the resistant cells using two-dimensional differential in-gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The proteomic analysis identified several proteins that were significantly altered relative to the parental 1A9 cells, including a decreased expression of vimentin in L4 cells. Using Western blotting and immunocytochemistry, the decrease in vimentin abundance seen in 2D-DIGE was confirmed. Vimentin levels were unchanged in the PLA-resistant R1 cells as well as two paclitaxel/epothilone-resistant sublines of 1A9 cells. Transfection with a full-length human vimentin cDNA partially restored sensitivity of L4 cells to PLA and LAU by 23% and 17% respectively. In vimentin-expressing parental 1A9 cells, tubulin-targeting and DNA-damaging agents caused degradation of vimentin and generation of vimentin degradation products. In conclusion, this study is the first to demonstrate a novel function for vimentin as a cellular determinant of the response to microtubule stabilizing agents, and that this effect is likely to be associated with the mode of cell killing by these agents. Since many of the proteins identified in this study have not previously been shown to play a role in drug resistance, our results also introduce potential new mechanisms by which cancer cells may become resistant to antimicrotubule agents.
Abstract B29: TGF-β2 induction in head and neck squamous cell carcinoma cell lines upon treatment with tyrosine kinase inhibitors as a mechanism of acquired resistance
Authors: Kleczko Emily K. , Heasley Lydia , Heasley Lynn E. 
Published: March 2013

Abstract
Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cancer worldwide, with 600,000 new diagnoses each year. Due to the fact that over 90% of HNSCC tumors overexpress the epidermal growth factor receptor (EGFR), molecularly targeted therapy against EGFR was approved to treat HNSCC. However, the 5-year survival rate for HNSCC patients, largely unchanged over the past several decades, remains at a dismal 40–50%, and the use of cetixumab, an EGFR-specific monoclonal antibody, has only had a marginal effect on overall survival. Likewise, the use of tyrosine kinase inhibitors (TKIs) that target EGFR has not resulted in an increased survival among HNSCC patients. The modest effect of these drugs on overall survival in HNSCC patients may be a result of tumors becoming resistant to treatment in responding patients. Acquired drug resistance has become a significant limitation to the efficacy of targeted therapeutics. Previously, our lab has identified fibroblast growth factor 2 (FGF2) and its receptor (FGFR) as being involved in an autocrine loop in gefitinib-insensitive cell lines, indicating that the FGFR pathway plays an important role in HNSCC as well. However, targeting FGFR with TKIs will almost undoubtedly lead to drug resistance in these FGFR-dependent cell lines, just as it does when targeting EGFR. To identify pathways important in acquired resistance to TKIs, our lab performed an Affymetrix GeneChip screen in which the cell lines UMSCC25, 584-A2, and Ca9-22 were treated for 4 days with 0.3μM AZ8010, a TKI selective for FGFRs, and/or 0.1μM gefitinib, an EGFR-selective TKI. TGF-β2 was consistently upregulated after treatment with TKIs that inhibited the dominant growth pathway in the HNSCC cell lines. Both ELISA and qRT-PCR confirmed this induction of TGF-β2 in these three cell lines. Treatment with a TGF-β2 neutralizing antibody and with small-molecule TGF-β receptor inhibitors provided additive reduction of growth in response to TKIs. Additionally, silencing TGF-β2 with shRNA in the cell line UMSCC25 leads to decreased clonogenic growth in combination with TKIs compared to a non-silencing control (NSC). Moreover, we found that an induction of NF-kB activity occurs in response to treatment with TKIs, and this induction is mitigated by the addition of a TGF-β2 neutralizing antibody. Furthermore, the cell lines UMSCC25 and UMSCC22A were chronically adapted to gefitinib over the course of several months, and we have observed a stable, prolonged increase in TGF-β2 mRNA expression in the resistant lines compared to the DMSO control lines. Taken together, this data suggests that TGF-β2 induction may provide a novel mechanism of acquired resistance to TKIs, and possibly contributes to oncogene switching programs in HNSCC.
Abstract B3: Angiotensin IV-Related Hepatocyte Growth Factor Antagonists act as Anti-Angiogenic Anti-Cancer Agents
Authors: Kawas Leen H. , Ward Brandi C. , Mojica Chromewell , Wright John W. , Harding Joseph W. 
Published: March 2013

Abstract
Hepatocyte growth factor (HGF) promotes tumor angiogenesis by both vascular endothelial growth factor (VEGF)-dependent and VEGF-independent mechanisms. The VEGF-dependent action of HGF relies on its ability to induce VEGF expression while the VEGF-independent mechanism appears to involve the direct activation of Akt and ERK. This later mechanism may also be an important contributor to development of tumor resistance to anti-VGEF (anti-angiogenic) drugs. As such, the rational design of newer therapeutics that target and inhibit HGF may provide a more complete and long-lasting therapeutic effect. Angiogenesis, the development of new blood vessels, is essential for tumorigenesis. Tumor cells often up-regulate the production of pro-angiogenic growth factors such as the HGF. The angiotensin IV analog Norleual has been shown recently to act as an HGF/Met antagonist, inhibiting HGF dimerization and activation, blocking the binding of HGF to its Met receptor, impeding HGF-dependent activation of Met, and attenuating HGF-dependent cellular activities. Here we show for the first time that Norleual can inhibit the proliferation and migration of human endothelial cells. Further Norleual treatment results in a dramatic loss of deposited extracellular matrix proteins from both human endothelial and murine breast cancer cells. As anticipated from the abovementioned studies, Norleual markedly attenuated both ex vivo and in vivo angiogenesis. These results were extended to a murine breast cancer model where Norleual dramatically suppressed both tumor growth and vascularization. The major implication of this study is that molecules targeting the HGF/Met system like Norleual are powerful antiangiogenics and may be useful in combination with anti-VGEF drugs (multitargeted approach) to inhibit pathophysiological angiogenesis. Rational combination therapies may help in decreasing the possibility for drug resistance development and resolving issues related to toxicity.
Abstract B31: HuR cytoplasmic translocation and doxorubicin: how phosphorylation is involved in chemoresistance
Authors: Latorre Elisa , Quattrone Alessandro , Provenzani Alessandro 
Published: March 2013

Abstract
Introduction: HuR, an RNA binding protein involved in the post-transcriptional regulation of a wide spectrum of mRNAs, has been demonstrated to be a determinant of carcinogenesis and tumor aggressiveness in several cancer types. In this study, we identified HuR as a key protein in the mechanisms leading to the insurgence of chemoresistance induced by the widely used anticancer drug doxorubicin in human breast cancer cells (MCF-7) and investigated the signaling pathways responsible of its activation.
Material and methods: We challenged a small library of about 90 chemical compounds with a high-content screening assay to quantitavely measure HuR translocation. Hits pointed to PKCδ, Rho kinase and ERK as potential HuR regulators.
Results and discussion: We showed that HuR acts in the early phase of cell response to doxorubicin, being induced to translocate into the cytoplasm upon phosphorylation. Reducing HuR levels diminished the apoptotic response to doxorubicin. We identified HA1004, AG494, U0126, AG490 and Erbstatin compounds that could inhibit HuR cytoplasmic accumulation directly hampering HuR phosphorylation or indirectly blocking kinase pathways. Among the hits rottlerin showed to be the most effective in blocking HuR nuclear export and in having correspondingly antagonistic effects with doxorubicin on cell toxicity. Co-immunoprecipitation of PKCδ and HuR upon doxorubicin confirmed the validity of HCS indications. In in vitro selected doxorubicin resistant MCF-7 cells (MCF-7/doxoR) overexpressing the multidrug resistance (MDR) related ABCG2 transporter, we observed a significant HuR downregulation that was paralleled by a corresponding downregulation of HuR targets as TOP2A and by loss of rottlerin toxicity. Restoration of HuR expression in these cells resensitized MCF-7/doxoR cells to doxorubicin, reactivating the apoptotic response.
Conclusions: The present study shows that HuR is necessary to elicit the apoptotic cell response to doxorubicin, that restoration of HuR expression in resistant cells resensitizes them to the action of this drug. Moreover we suggest a novel mechanism of pharmacoresistance based on the interplay among the doxorubicin target TOP2A, its post-transcriptionally regulator HuR and the signaling control of PKCδ.
Abstract B34: Bortezomib induces G2-M arrest through ROS-inducible phosphorylation of ATM-CHK1 in human colon cancer cells
Authors: Seung-Woo Hong , Won Kim Tae , Jai-Hee Moon , Yong-Sang Hong , Dong-Hoon Jin , Jae-Sik Shin , Hyun Yoon Dok , Kyu-pyo Kim , Jae-Lyun Lee , Jung Shin Lee 
Published: March 2013

Abstract
Colorectal cancer (CRC) is one of the most common cancer types, however, newer drug development has reached a plateau at present. Bortezomib (PS-341, Velcade®) is a proteasome inhibitor and approved in the treatment of hematologic malignancies including multiple myeloma. A few trials of bortezomib alone or combination chemotherapy for CRC patients have been reported, however, the results were not so satisfactory, and it might be due to the lack of understanding on the action mechanism. In this report, we suggest the possibility of using bortezomib as a proteasome inhibitor in human colon cancer cells. Although bortezomib has been known to induce apoptosis and cell cycle arrest in various human cancer cells, the inhibitory mechanism of it was not clear. First, bortezomib induced G2-M arrest. Its treatment causes an increase of intracellular reactive oxygen species (ROS) levels and activation of ATM-CHK1 pathway, but not ATR. Also, activation of that pathway led to inactivation of cdc2. Moreover, treatment with NAC, ROS scavenger, inhibited phosphorylation of ATM and subsequent to decrease of cell number at G2-M phase in response to bortezomib indicating that the increased level of ROS after exposure to bortezomib is a result of ATM phosphorylation. In addition, knockdown of endogenous ATM by RNA interference induced the decreased sensitivity to bortezomib. Therefore, these results suggest that bortezomib induces G2-M arrest through ROS-inducible ATM phosphorylation and shows antitumor activity in human colon cancer cells, implying a potential possibility of further investigations in the treatment of CRC patients.
Acknowledgement: This study was supported by grants from the Korea Health 21 R&D Project, Ministry of Health and Welfare and Family Affairs, Korea (A062254).
Abstract B35: Alternate receptor tyrosine kinases provide protection from FGFR inhibition in HNSCC cells as identified by genome-wide shRNA screening
Authors: Singleton Katherine R. , Tan Aik-Choon , Kim Jihye , Heasley Lynn 
Published: March 2013

Abstract
The efficacy of many biologically targeted cancer therapies is limited by intrinsic and acquired resistance. Head and neck squamous carcinoma (HNSCC) patients show only a 4–10% response to the epidermal growth factor receptor (EGFR) inhibitors, gefitinib and erlotinib, despite EGFR over-expression in over 90% of tumors. Our lab has previously shown that gefitinib insensitive non-small cell lung cancer (NSCLC) cell lines exhibit dominant autocrine fibroblast growth factor receptor (FGFR) signaling. RNAi-based loss-of-function screens are an important tool to identify synthetic lethal interactions between the inhibition of two genes in order to efficiently identify functional survival mechanisms and potent drug combinations. We deployed a whole genome screen to identify genes whose knockdown potentiated the inhibitory effect of the FGFR inhibitor, AZ12908010, in HNSCC cell lines. We found that multiple alternate receptors provided protection from FGFR inhibition in these cell lines, including the receptor tyrosine kinases (RTKs) epidermal growth factor receptor 2 (ErbB2) and hepatocyte growth factor receptor (Met). We validated the results of the screen by showing that specific knockdown of either ErbB2 or Met in combination with FGFR inhibitor treatment led to increased inhibition of growth relative to FGFR tyrosine kinase inhibitor (TKI) treatment alone. These results were confirmed using specific small molecule inhibitors of either ErbB2 or Met. The combination therapies did not lead to greater inhibition of growth in the cell lines where ErbB2 and Met were not identified as synthetic lethal with FGFR. We extended the study to find that the combination of knockdown of either ErbB2 or Met with FGFR inhibition decreased the growth of additional cell lines, indicating that the combination therapies could be broadly applicable. These results reveal a role for alternate RTKs in maintaining pro-growth and survival signaling in HNSCC cells in the setting of FGFR inhibition. Thus, improved therapies for HNSCC patients could involve rationally designed combinations of TKIs targeting FGFR and either ErbB family members or Met.
Abstract B40: Paracrine interactions through CXCL1/2 chemokines promote breast cancer metastasis and chemoresistance
Authors: Acharyya Swarnali , Oskarsson Thordur , Vanharanta Sakari , Malladi Srinivas , Kim Juliet , Brogi Edi , Norton Larry , Massague Joan 
Published: March 2013

Abstract
Cancer progression is a complex process that involves tumor growth at the primary site coupled with metastatic colonization and outgrowth at a distant organ site. In the case of solid tumors, 90% of deaths are known to occur from metastasis. Searching for mediators of breast cancer progression and metastasis, we identified a signature of 18 genes, the expression of which in primary tumors could predict the risk of lung metastasis recurrence in over 700 breast cancer patients. The sole chemokine in the lung metastasis signature is CXCL1, a member of the C-X-C family of chemokines. We find that increased expression of CXC family members could be explained in part by amplification of 4q21, a locus that harbors CXCL1-8 in breast tumors and metastases that we examined. Investigating the functional role of the C-X-C family in breast cancer metastasis led us to uncover a series of paracrine interactions mediated by CXCL1 and CXCL2 with components of the tumor microenvironment. Using breast cancer cell lines, primary patient derived cells and transgenic mouse models of mammary cancer and lung metastasis, we show that CXCL1/2 serve dual functions promoting both primary tumor growth and lung metastasis. We also demonstrate that CXCL1/2 recruits myeloid subpopulations that are essential in mediating cancer cell survival. Using small molecule inhibitors targeting CXCL1/2 signaling, we elucidate that this chemokine axis is critical in mediating breast cancer metastasis to lung and can be pharmacologically targeted.
The standard treatment for metastatic breast cancer is a combination of chemotherapeutic drugs. Disappointingly, these therapies only provide limited benefit and almost always result in relapse with acquired resistance and deadly consequences. We found that CXCL1, CXCL2 and other related family members were frequently upregulated in breast cancer models exposed to a variety of cytotoxic agents such as doxorubicin and taxanes. Moreover, our study revealed previously unknown tumor-stroma interactions that are initiated by CXCL1/2 in response to chemotherapy. Additionally, our functional studies in animal models and clinical evidence from patient samples demonstrated a function of CXCL1/2 in mediating chemoresistance. Interestingly, pharmacological inhibition of the CXCL1/2 paracrine axis in combination of chemotherapy significantly sensitized breast tumors to the therapy. In particular, combined treatment dramatically reduced the outgrowth of cancer cells at the lung metastatic site. Together, our findings reveal a network of tumor-microenvironment interactions mediated by the CXC chemokine axis that promotes tumor growth and metastasis on one hand and chemoresistance on the other.
Abstract B41: Thymoquinone induces-cell cycle non-specific-cell death in cisplatin-resistant ovarian cancer cell through up-regulation of PTEN expression
Authors: Arafa El-Shaimaa A. , Wani Altaf A. 
Published: March 2013

Abstract
Ovarian carcinoma is one of the most prevalent and lethal gynecological malignancies, and is the fifth leading cause of cancer death among women in the United Stat. Like most malignancies, ovarian cancer is a heterogeneous disease characterized by multiple molecular alterations. These include loss of function of tumor suppressor genes, deregulation of Bcl-2 family proteins, inhibition of caspase activation, and activation of cellular survival signaling pathways, such as HER-2/neu and phosphatidylinositol-3 kinase PI3K/Akt. Over years the use of natural compounds as anticancer agents acquired great importance. Thymoquinone (TQ) is the main bioactive component of the volatile oil of the black seed (Nigella sativa, Ranunclulaceae family). TQ has been used as antioxidant, anti-inflammatory, and antineoplastic medicines for more than 2,000 years. Previous studies reported that TQ exhibited inhibitory effects on cell proliferation of many types of cancer cell lines, including breast adenocarcinoma, lung adenocarcinoma, colorectal cancer, etc. Here, we report that TQ greatly inhibited cell proliferation of cisplatin-resistant ovarian cancer cells (A2780/CP70) 24, 48 and 72 hours after treatment in a concentration-dependent manner. However, our flow cytometry data revealed that TQ is a cell cycle non-specific for CP70 cells. Our results also showed that TQ upregulated PTEN and p53 in CP70 cells while downregulated phospho-Akt in a dose-dependent manner. Current investigations are ongoing to fully understand the mechanism of action of TQ in cisplatin-resistant ovarian cancer cells.
Abstract B44: Combination treatments of SCLC with ABT-263 and Immunotoxins produces synergistic killing of ABT-263-resistant cells
Authors: Mattoo Abid R. , Fitzgerald David J. 
Published: March 2013

Abstract
Small cell lung cancer (SCLC) cell lines are variably sensitive to the BH-3 only peptide mimetic, ABT-263. To determine their sensitivity to toxin-based reagents, we incubated four representative SCLC lines with a model Pseudomonas exotoxin-based immunotoxin directed to the transferrin receptor. Remarkably in 4-of-4 lines, there was little evidence of immunotoxin-mediated cytotoxicity despite near complete inhibition of protein synthesis. However, when combinations of ABT-263 and immunotoxin were added to the ABT-263-resistant cell lines (H196 and H69AR), there was synergistic killing as evidenced by increased activation of caspase 3/7, annexin V staining and loss of cell integrity. This synergy was also noted when the closely related compound ABT-737 was combined with the same immunotoxin. To establish that the synergy seen in tissue culture could also be achieved in vivo, H69AR cells were grown as tumors in nude mice and shown to be susceptible to the killing action of an immunotoxin-ABT combination but not to either agent alone. When immunotoxin-ABT combinations were added to ABT-263-sensitive lines (H146 and H889), killing was primarily due to the action of ABT-263. Our data support combination approaches for treating ABT-263-resistant SCLC with ABT-263 and a second agent that provides synergistic killing action.