bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 772: CCL2 regulates EMT-mediated chemo-resistance in prostate cancer
Authors: Wang Wenchu , Lu Yi , Zhou Xiaolin , Mizokami Atsushi , Keller Evan , Zhang Jian 
Published: May 2015

Abstract
Prostate cancer is one of the most common cancers and the second leading cause of cancer-related death in western countries. In China, the incidence has increased, unexpectedly and sharply, for the past 20 years. Chemo-resistance, in various types of tumor including prostate cancer, is one of the critical problems in cancer therapy. In prostate cancer, for example, the resistance to taxanes (paclitaxel or docetaxel, DTX) accounts for tumor relapse and progression resulting in skeletal metastasis and high mortality. Epithelial-mesenchymal transition (EMT) has been suggested as a key process that dominates chemo-resistance through unknown mechanisms. In the current study, we reported that CCL2 serves as key molecules in EMT-mediated chemo-resistance in prostate cancer cells using paclitaxel-resistant cells, DU145-TxR, PC-3-TxR and C4-2B-TxR. Parental prostate cancer cells were used as controls. We observed that DU145-TxR, PC-3-TxR and C4-2B-TxR cells produced significantly higher amount of CCL2 compared to their parental cells, determined by cytokine array. In addition, DU145-TxR, PC-3-TxR and C4-2B-TxR cells demonstrated EMT phenotypes including hall maker changes in E-cadherin and Vimentin expression and transcriptional factor (Snail, ZEB1, and Slug) alterations, examined by western blot. These changes were reversed partially by adding neutralizing antibodies against CCL2. Finally DU145-TxR, PC-3-TxR, and C4-2B-TxR or their parental cells were implanted into SCID mice and the mice were given DTX (10mg/kg, biweekly) and tumor growth was monitored for 4 weeks. Both DU145-TxR, PC-3-TxR and C4-2B-TxR tumors grew faster than the parental tumors. Tumor tissues were collected and total RNAs were isolated. Levels of CCL2 expression in these tumors were significantly higher in DU145-TxR, PC-3-TxR and C4-2B-TxR tumors. IHC analysis confirmed corresponding staining of EMT markers such as E-cadherin and Vimentin expression. Together we concluded that CCL2 regulates EMT-mediated chemo-resistance in prostate cancer. These results are of high impact of human prostate cancer chemotherapy. Supported by U.S. Department of Defense PC061231; NSF key project 81130046; NSF projects 81171993 and 81272415.
Citation Format: Wenchu Wang, Yi Lu, Xiaolin Zhou, Atsushi Mizokami, Evan Keller, Jian Zhang. CCL2 regulates EMT-mediated chemo-resistance in prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 772. doi:10.1158/1538-7445.AM2014-772
Abstract 773: Restoration of LKB1 defect in EKVX cells leads to resistance to microtubule targeting agents
Authors: Mao Kaisheng , Liu Fakeng , Liu Xiuju , He Yulong , Khuri Fadlo , Marcus Adam , Li Mingsong , Zhou Wei 
Published: May 2015

Abstract
LKB1 is frequently inactivated in non-small cell lung cancers, probably because of its role in suppressing tumor metastasis. Here, we identified a novel LKB1 mutation in the EKVX lung adenocarcinoma cell line, where serine216 in the kinase domain was mutated to phenylalanine. Genomic sequencing revealed this change to be homozygous, suggesting that the other allele was probably eliminated through a loss of heterozygosity mechanism. We also demonstrated that EKVX cells are defective in energetic stress-induced AMPK phosphorylation, which can be restored by the re-establishment of wild-type but not mutant LKB1 expression. This is consistent with the role of LKB1 as an upstream kinase for AMPK in energetic stress conditions. Interestingly, expression of wild-type LKB1 in EKVX cells was found to be resistant to microtubule targeting agents, such as paclitaxel or vinblastine by SRB analysis. Cell cycle analysis indicated that while the parental or LKB1-mutant expressing cells enter mitotic arrest after 25nM paclitaxel treatment, EKVX-LKB1 cells failed to enter G2/M arrest. Immunofluorescence analysis also revealed a decrease in microtubule bundling after 50nM paclitaxel treatment in EKVX cells with wild-type LKB1 expression. This phenomenon, however, was not observed in other natural LKB1-null A549 or H460 cells. Therefore, our data suggest that the re-establishment of LKB1 expression might lead to resistance to microtubule targeting agents in a subset of non-small cell lung cancer cells with LKB1 mutation.
Citation Format: Kaisheng Mao, Fakeng Liu, Xiuju Liu, Yulong He, Fadlo Khuri, Adam Marcus, Mingsong Li, Wei Zhou. Restoration of LKB1 defect in EKVX cells leads to resistance to microtubule targeting agents. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 773. doi:10.1158/1538-7445.AM2014-773
Abstract 774: EGFR-regulated RGS expression contributes to paclitaxel resistance in human lung cancer cells
Authors: Park Shin-Hyung , Sung Myung-A , Lee Ho-Young 
Published: May 2015

Abstract
Lung cancer is one of the main causes of cancer-related death worldwide, and the 5-year survival of lung cancer is less than 20%. Paclitaxel is a widely used chemotherapeutic agent to treat a variety of cancers, but its therapeutic efficacy tends to be limited due to the development of drug resistance, raising the need to understand the molecular mechanisms underlying paclitaxel resistance. In the current study, we investigated the mechanisms of paclitaxel resistance in non-small cell lung cancers (NSCLCs). First, we established paclitaxel-resistant NSCLC cell lines, including H460 TxR and SK-MES TxR, by pulse- or prolonged treatment of paclitaxel. The IC50 value of paclitaxel-resistant cell lines was 50 fold less than that of parental cells. Upon paclitaxel treatment, H460 TxR and SK-MES TxR sublines experienced markedly greater anchorage-dependent and -independent colony forming abilities with reduced apoptosis than did the parental cell lines. Next, we investigated the underlying molecular mechanism of acquired resistance against paclitaxel. Through microarray analysis, we found 19 genes commonly-increased both in H460 TxR and SK-MES TxR. Among them, the expression of regulator of G-protein signaling (RGS) gene increased the most. Knockdown of RGS gene expression by siRNA sensitized the paclitaxel-resistant cells to the drug treatment in vitro. Furthermore, H460 TxR xenograft mice showed a significant decrease in tumor growth after combined treatment with siRGS and paclitaxel, implying the association of RGS with paclitaxel resistance in NSCLC. To identify the mechanisms involved in increase in RGS expression, we assessed the phosphorylation level of several kinases involved in cell proliferation and survival. Among them, epidermal growth factor receptor (EGFR) showed the most significant phosphorylation. EGFR inhibition by erlotinib down-regulated RGS expression in a transcriptional level, leading to the enhanced sensitivity to paclitaxel in H460 TxR. Taken together, our results indicate that RGS overexpression is a mediator of paclitaxel resistance in NSCLCs and represent the first link between RGS and chemoresistance. We suggest that RGS might be a potential target of therapeutic strategies for lung cancer patients with paclitaxel resistance.
Citation Format: Shin-Hyung Park, Myung-A Sung, Ho-Young Lee. EGFR-regulated RGS expression contributes to paclitaxel resistance in human lung cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 774. doi:10.1158/1538-7445.AM2014-774
Abstract 777: Efficacy of nab-paclitaxel on 5-fluorouracil (5-FU) resistant human gastric cancer cell lines
Authors: Nukatsuka Mamoru , Kobunai Takashi , Matsuoka Kazuaki , Takechi Teiji 
Published: May 2015

Abstract
Purpose: 5-Fluorouracil (5-FU)-based combination chemotherapy is widely used for the treatment of advanced gastric cancer in Japan. Thus, the development of effective chemotherapy for 5-FU-resistant gastric cancer after 5-FU-based chemotherapy is important. Nab-paclitaxel is an albumin-bound, 130-nm particle form of paclitaxel that exhibits a higher activity and lower toxicity than solvent-based paclitaxel. In the present study, the activity of nab-paclitaxel alone or in combination with 5-FU was evaluated in four 5-FU resistant cell lines.
Method: 5-FU-resistant human gastric cancer cell lines were established from parent cells (MKN-45, MKN-74, NCI-N87, and KATO-III) by continuous exposure to escalating concentrations of 5-FU over a one-year period. The sensitivities of these cell lines to chemotherapeutic agents (5-FU and nab-paclitaxel) were evaluated using the WST-8 colorimetric assay. To evaluate the effects of the combination of 5-FU and nab-paclitaxel, the combination index (CI) value was calculated using CalcuSyn 2.0 (Biosoft, Cambridge, UK). The gene expressions of secreted protein acidic and rich in cysteine (SPARC) in the parent and 5-FU-resistant cell lines were evaluated using a Whole Human Genome 44K oligo DNA microarray (Agilent Technologies, Santa Clara, CA).
Results: The IC50 value of 5-FU ranged from 2.35 to 36.7 μM, and its ratio (resistant cell lines/parent cell lines) ranged from 2.6 to 15.6. The IC50 value of nab-paclitaxel ranged from 4.45 to 54.5 nM, and its ratio ranged from 1.0 to 1.2. Therefore, the 5-FU-resistant cell lines used in this study showed no signs of cross-resistance to nab-paclitaxel. The calculated CI value treated with 5-FU and nab-paclitaxel was approximately 1; therefore, nab-paclitaxel additively inhibited the cell growth when administered in combination with 5-FU. Interestingly, the combination of 5-FU and nab-paclitaxel had an additive cytotoxic activity in the 5-FU-resistant human gastric cell lines in vitro. The relative expression of SPARC mRNA in the resistant cell lines to that in the parent ones ranged from 0.86 to 1.47, and SPARC expression might be weakly correlated with the acquisition of 5-FU resistance. Conclusion: Nab-paclitaxel might be a promising agent for the treatment of 5-FU-resistant human gastric cancer when used alone or in combination with 5-FU. These results suggest that nab-paclitaxel might be a promising chemotherapy for gastric cancer patients who relapse after undergoing 5-FU-based chemotherapy.
Citation Format: Mamoru Nukatsuka, Takashi Kobunai, Kazuaki Matsuoka, Teiji Takechi. Efficacy of nab-paclitaxel on 5-fluorouracil (5-FU) resistant human gastric cancer cell lines. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 777. doi:10.1158/1538-7445.AM2014-777
Abstract 778: Antioxidants decrease the apoptotic effect of 5-Fu in colon cancer by regulating Src-dependent caspase-7 phosphorylation
Authors: Fu Yang , Yang Ge , Zhu Feng , Peng Cong , Li Wei , Li Haitao , Kim Hong-Gyum , Bode Ann M. , Dong Ziming , Dong Zigang 
Published: May 2015

Abstract
Although the rate of development of drug resistance remains very high, 5-Fu is still the most common chemotherapeutic drug used for the treatment of colon cancer. A better understanding of the mechanism of why cancers develop resistance to 5-Fu could improve its therapeutic effect. Sometimes antioxidants are used simultaneously with 5-Fu treatment. However, a recent clinical trial showed no advantage or even a harmful effect of combining antioxidants with 5-Fu compared to administration of 5-Fu alone. The mechanism explaining this phenomenon is still poorly understood. In this study, we show that 5-Fu can induce reactive oxygen species-dependent Src activation in colon cancer cells. Mouse embryonic fibroblasts that are deficient in Src showed a clear resistance to 5-Fu, and knocking down Src protein expression in colon cancer cells also decreased 5-Fu-induced apoptosis. We found that Src could interact with and phosphorylate caspase-7 at multiple tyrosine sites. Functionally, the tyrosine phosphorylation of caspase-7 increases its activity, thereby enhancing cellular apoptosis. When using 5-Fu and antioxidants together, Src activation was blocked, resulting in decreased 5-Fu-induced apoptosis. Our results provide a novel explanation as to why 5-Fu is not effective in combination with some antioxidants in colon cancer patients, which is important for clinical chemotherapy.
Keywords: antioxidant; 5-Fu; Src; caspase-7; colon cancer; apoptosis
Citation Format: Yang Fu, Ge Yang, Feng Zhu, Cong Peng, Wei Li, Haitao Li, Hong-Gyum Kim, Ann M. Bode, Ziming Dong, Zigang Dong. Antioxidants decrease the apoptotic effect of 5-Fu in colon cancer by regulating Src-dependent caspase-7 phosphorylation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 778. doi:10.1158/1538-7445.AM2014-778
Abstract 78: A novel orthotopic mammary epithelial cell (MEC) transplantation model of breast cancer formation
Authors: Szucs Zoltan , Prater Michael D. , Stingl John , Brindle Kevin M. 
Published: May 2015

Abstract
The pathogenesis of breast cancer is polygenic. Exploring the involvement of different onco- and tumor suppressor genes, and combinations of these genes, in early breast cancer formation is important for understanding the natural history of the disease. Preclinical studies of the fundamental biological and metabolic changes that occur during breast oncogenesis in currently available transgenic mouse models are limited by the requirement for tissue-specific promoters and the random nature of tumor formation.
The mouse mammary gland is a unique organ in that most of its development occurs after birth. Moreover, isolated mammary epithelial cells (MECs) have the capacity to regenerate a functional gland upon orthotopic transplantation into the cleared fat pad of a syngeneic recipient. We describe here a new transplantation system using pure MECs derived from genetically engineered mice harboring floxed oncogenes. First we selected in vitro for a stromal and hematopoietic cell-free MEC preparation. In the MEC donor transgenic strains the activation of oncogenes (K-Ras, c-Myc) or the deletion of tumor suppressors (p53) is dependent on Cre recombinase expression (Cre-lox system). Using an adenoviral Cre-recombinase vector we activated these oncogenic changes in isolated MECs. Colony formation assays demonstrated the viability of these mixed transduced/non-transduced MEC populations. Following transplantation into the cleared fat pad of syngeneic mice the transduced MECs preserved their fat pad repopulating and duct forming potential and the induced oncogenic changes resulted in mammary tumor formation. This proposed system offers tissue specific promoter-free and lactation independent spatial control of oncogenic events in the epithelial cell compartment of breast ducts.
Citation Format: Zoltan Szucs, Michael D. Prater, John Stingl, Kevin M. Brindle. A novel orthotopic mammary epithelial cell (MEC) transplantation model of breast cancer formation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 78. doi:10.1158/1538-7445.AM2014-78
Abstract 782: Transmembrane 2-3 loop domain of the proton coupled folate transporter (PCFT) forms a novel “reentrant loop” structure and is functionally important
Authors: Wilson Michael R. , Hou Zhanjun , Matherly Larry H. 
Published: May 2015

Abstract
The proton coupled folate transporter (PCFT) is a proton-folate symporter with a twelve transmembrane domain (TMD) structure. Human PCFT (hPCFT) is highly expressed in many solid tumors and has an acidic pH optimum, suggesting its high activity in the acidic tumor microenvironment. Our recent studies have focused on exploiting PCFT for targeting solid tumors with novel cytotoxic antifolates. Predicted topology models suggest that the loop domain between TMDs 2 and 3 resides in the cytosol. However, mutations in TMD2-3 loop residues Asp109 or Arg113 result in loss of PCFT activity, suggesting an important role in transport activity. Additionally, TMD2 may itself form a part of the substrate binding domain, suggesting functional importance for TMD2 residues. Using site-directed mutagenesis, we replaced each of the seven cysteine (cys) residues of hPCFT with serine, creating functional “cys-less” PCFT for use in substituted cys accessibility methods (SCAM). We then used site-directed mutagenesis to create 34 single cys mutants spanning TMD2 and the TMD 2-3 loop region (positions 85-118) in a cys-less PCFT background. These mutants were transfected into R1-11 HeLa cells, which express no endogenous folate transporters. We measured [3H]methotrexate uptake at pH 5.5 as a readout of PCFT activity and confirmed PCFT protein expression by western blotting. All 34 mutants were detected on westerns and 29 mutants were active, while W107C, D109C, G112C, R113C, and R114C were inactive. Using functionally active mutants, we performed pull-down assays with 2-aminoethyl methanethiosulfonate-biotin (MTSEA-biotin) and steptavidin beads, in order to determine the aqueous accessibility of each mutant. We found that mutants G93C, F94W, G105C, A106C, S110C, and L116C reacted with MTSEA-biotin, suggesting that these residues are aqueous-accessible. For G93C, F94C, and L116C, MTSEA-biotin labeling was inhibited by pemetrexed pretreatment, and MTSEA-biotin treatment inhibited transport activity of G93C and F94C. Our results suggest that the TMD 2-3 loop domain is aqueous accessible and must form a novel functionally important “reentrant loop” structure. Additionally, residues located in TMD2 (Gly93 and Phe94) appear to play a key role in substrate binding to PCFT. Better understanding of functional and structural determinants of PCFT membrane transport will be critical to the development of novel PCFT-selective antifolate drugs for targeting solid tumors.
Citation Format: Michael R. Wilson, Zhanjun Hou, Larry H. Matherly. Transmembrane 2-3 loop domain of the proton coupled folate transporter (PCFT) forms a novel “reentrant loop” structure and is functionally important. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 782. doi:10.1158/1538-7445.AM2014-782
Abstract 784: Significance of osteopontin in the sensitivity of malignant pleural mesothelioma to pemetrexed
Authors: Takeuchi Susumu , Seike Masahiro , Noro Rintaro , Soeno Chie , Sugano Teppei , Zou Fenfei , Matsumoto Masaru , Miyanaga Akihiko , Minegishi Yuji , Kubota Kaoru , Gemma Akihiko 
Published: May 2015

Abstract
Background: Pemetrexed (PEM) is currently recommended as one of the standard anticancer drugs for malignant pleural mesothelioma (MPM). However, the mechanism of the sensitivity of MPM to PEM remains unclear.
Materials and Methods: We analyzed the antitumor effects of PEM in six MPM cell lines by MTS assay. To identify genes associated with drug sensitivity, we conducted gene expression profiling on the same set of cell lines using GeneChips and pathway analysis.
Results: Three cell lines were sensitive to PEM. Eighteen transcripts and fourteen genes identified by Gene-chips were significantly correlated with sensitivity to PEM. Pathway analysis revealed that osteopontin (SPP1/OPN) was an important target in PEM sensitivity. Overexpression of SPP1/OPN was observed in the sensitive cells by quantitative RT-PCR analysis and Western blotting. Introduction of SPP1/OPN by lentiviral vector significantly enhanced the invasion activities of MPM cells. PEM treatment with SPP1/OPN knockdown inhibited the PEM-induced cell growth-inhibitory effect in PEM-sensitive cells. Expression of SPP1/OPN and AKT phosphorylation significantly decreased after PEM treatment of the PEM sensitive cells. High immunohistochemical expression of SPP1/OPN was observed in two of three MPM patients who had a partial response to PEM-based chemotherapy.
Conclusion: PEM has anti-tumor effects in MPM cells dependent on SPP1/OPN overexpression resulting in AKT activation. Our results suggest that SPP1 may be used as a single predictive biomarker of the effectiveness of PEM treatment in MPM.
Citation Format: Susumu Takeuchi, Masahiro Seike, Rintaro Noro, Chie Soeno, Teppei Sugano, Fenfei Zou, Masaru Matsumoto, Akihiko Miyanaga, Yuji Minegishi, Kaoru Kubota, Akihiko Gemma. Significance of osteopontin in the sensitivity of malignant pleural mesothelioma to pemetrexed. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 784. doi:10.1158/1538-7445.AM2014-784
Abstract 788: Lichen-derived metabolites show synergistic effects in combination with lapatinib and doxorubicin against breast cancer cells
Authors: Bessadottir Margret , Skuladottir Edda A. , Baldursson Sindri , Omarsdottir Sesselja , Ögmundsdottir Helga M. 
Published: May 2015

Abstract
Protolichesterinic acid (PA) is the major biologically active second metabolite of the lichen Cetraria islandica. PA has anti-proliferative effects on several types of cancer cells, but no effect on normal skin fibroblasts and is an inhibitor of 5- and 12-lipoxygenase (LOX). Usnic acid (UA) (from Cladonia arbuscula) has a wide range of biological activities, e.g. anti-inflammatory, anti-viral and anti-bacterial activity. UA affects pH gradients and inhibits growth and proliferation of several cancer cells.
Fatty acid synthase (FASN) is up-regulated in a variety of cancers. Overexpression of human epidermal growth factor receptor 2 (HER2) has been linked to increased translation of FASN. The chemical structure of PA is very similar to the FASN inhibitor, C75. FASN inhibition interacts synergistically with HER2 targeted drugs (e.g. lapatinib) in breast cancer cells and can overcome resistance. Doxorubicin stops DNA replication. The accumulation and distribution of doxorubicin in cells is pH-dependent. Synergistic effects of the lichen compounds and lapatinib or doxorubicin were estimated, using the CalcuSyn software, in the breast cancer cell lines, SK-BR-3 (HER2+, high levels of FASN) T-47D (P53-mutated) and MCF7. Significant synergistic effects were obtained in SK-BR-3 cell line after combined treatment with PA/lapatinib, and in T-47D cells but at higher concentrations. No synergism was seen in MCF7 cells. Treatment with UA/doxorubicin showed marked synergism at all tested concentrations in T-47D cells; none was seen in SK-BR-3 cells. Synergism between a lichen compound and a drug can be related to metabolic effects. Moreover the synergistic effects appear to be cell-type-dependent.
Citation Format: Margret Bessadottir, Edda A. Skuladottir, Sindri Baldursson, Sesselja Omarsdottir, Helga M. Ögmundsdottir. Lichen-derived metabolites show synergistic effects in combination with lapatinib and doxorubicin against breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 788. doi:10.1158/1538-7445.AM2014-788