bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1667: In vitro and in vivo validation of CSE1L/hCAS as a potential molecular target in pancreatic cancer
Authors: Husain Kazim , Coppola Domenico , Centeno Barbara , Helm Richard , Dung-Tsa Chen , Sebti Said , Malafa Mokenge
Published: June 2012

Background: The human cellular apoptosis susceptibility protein (hCAS) is a Ran- binding protein playing a role as mitotic spindle checkpoint regulator and as nuclear export factor. hCAS expression is frequently altered in metastatic cancers. To date the role of hCAS in pancreatic cancer is unknown. Therefore this study aimed to investigate the role of hCAS in human pancreatic cancer in vitro and in vivo.

Methods: The hCAS protein expression was determined using Western immunoblotting in human pancreatic cancer cell lines (AsPc-1, BxPc-3, Capan-2, MiaPaCa-2, Panc-1, and SW1990) and immortalized normal human pancreatic ductal epithelial cell (HPNE) and HPNE-Kras. siRNA induced hCAS knockdown pancreatic cancer cells were compared to scrambled siRNA cells with regard to proliferative (MTT assay), cell death, cell cycle (Trypan blue and Flow cytometry), malignant transformation (colony formation assay) and protein expression (Western and confocal microscopy). hCAS KD MiaPaCa-2 cells were xenografted in SCID nude mice. Tumor growth, expression of hCAS, proliferation index (Ki-67), and caspase-3 were immunostained in tumor tissues and compared with scr siRNA MiaPaCa-2 cells. Expression of hCAS was determined in human pancreatic tumor tissues using immunohistochemical stain.

Results: hCAS protein expression was low in HPNE cells compared to HPNE-Kras. Lowest expression of hCAS noted in BxPc-3 cells compared to other pancreatic cancer cells. When compared to Scr-MiaPaCa-2, KD-MiaPaCa-2 cells demonstrated lower proliferation, G2/M phase cell cycle arrest, increased apoptosis, as well as inhibition of malignant transformation. Pancreatic ductal carcinomas (PCA) were hCAS strongly positive. Normal pancreatic ducts (ND) were hCAS weakly positive. hCAS KD-MiaPaCa-2 tumor growth was retarded in mice compared to Scr-MiaPaCa-2 tumors. hCAS KD-MiaPaCa-2 tumors showed hCAS depletion, lower proliferative index, increased caspase-3 immunostaining and PARP1 cleavage.

Conclusion: This is the first report of hCAS expression in human pancreatic cancer. Our data suggest that hCAS is a regulator of cell proliferation, cell cycle regulation and apoptosis. hCAS may represent a potential chemopreventive and therapeutic target for human pancreatic 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 1667. doi:10.1158/1538-7445.AM2011-1667
Abstract 1677: Expression of lysophosphatidic acid acyltransferase-beta in human pancreatic ductal adenocarcinoma
Authors: Blaskovich Michelle A. , Coppola Domenico , Helm James , Sebti Said , Springett Gregory M.
Published: June 2012

Lysophosphatidic acid acyltransferase beta (LPAAT-β) is a new therapeutic target and prognostic marker in human cancer. The enzymatic function of LPAAT- β is to convert Lysophosphatidic Acid (LPA) to Phosphatidic Acid (PA), a lipid second messenger that functions to regulate the proliferation, adhesion, migration and survival of cancer cells. PA is an essential cofactor needed by the oncogenes c-Raf, BRAF, PKC-ζ and mTOR for their enzymatic and growth promoting activities in cancer. LPAAT-β protein over expression has been detected in tumors compared to normal tissue in ovarian, endometrial, breast and lung cancers. The over expression of LPAAT-β in ovarian tumors is associated with poor clinical outcome.

Methods: In this study we determined LPAAT-β expression in paired specimens of pancreatic ductal adenocarcinoma and adjacent non-malignant pancreas obtained from 102 patients who underwent pancreatectomy with curative intent (stage IA-IIB). Formalin-fixed, paraffin-embedded core sections in a tissue microarray were immunostained using the avidin-biotin-peroxidase method with rabbit anti- LPAAT-β antibody. A semi-quantitative measure of LPAAT-β expression was determined as the product of immunostain intensity and percentage of cells stained, where intensity and percentage were each scored on a scale of 0 to 3, with 3 being maximal.

Results: LPAAT-β expression (product score) in 57% (58/102) of pancreatic cancers was lower than in paired non-malignant pancreas, equal in 20% (20/102) of cancers, and greater in 23% (24/102) of cancers as compared to non-malignant pancreas. LPAAT-β expression in cancer (median product score = 3) was less than in non-malignant pancreas (median score = 4) (Wilcoxon signed-rank test, p < 0.0001).

Conclusions: Low LPAAT-β expression in pancreatic cancer as compared to non-malignant pancreas stands in contrast to previous studies showing increased LPAAT-β expression in several other cancers. This finding indicates that there may be tissue-specific differences in the biologic activity of LPAAT-β.

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 1677. doi:10.1158/1538-7445.AM2011-1677
Abstract 1681: Synergistic induction of Mek1/2 and Nox-1 by histone deacetylase inhibitors leads to differential induction of reactive oxygen species for mediating selective apoptosis of oncogenic H-Ras-expressing cells
Authors: Choudhary Shambhunath , Rathore Kusum , Sood Shilpa , Wang Hwa-Chain Robert
Published: June 2012

The goal of this study was to investigate roles of the ERK pathway and Nox-1 in the pro-apoptotic ability of oncogenic H-Ras to enhance histone deacetylase inhibitor (HDACI)-induced cell death. Oncogenic induction of the ras genes is widely involved in human cancers. Our previous studies revealed that expression of oncogenic H-Ras increases susceptibility of human and mouse cells to HDACIs, such as FK228 and trichostatin A, for inducing selective apoptosis. In this study, we used the mouse embryo fibroblast 10T1/2-TR-H-ras cell system, in which ectopic expression of oncogenic H-Ras(V12) is controlled by addition of tetracycline into cultures, and paired oncogenic H-Ras-expressing and parental human epithelial cells. We pursued the roles of Mek1/2 activation, Nox-1 elevation, and reactive oxygen species (ROS) production in FK228-induced selective cell death of oncogenic H-Ras-expressing cells versus counterpart cells. We verified that Nox-1 elevation and ROS played essential roles in oncogenic H-Ras-induced cell proliferation and morphological transformation. We also detected that FK228 treatment and expression of oncogenic H-Ras synergistically induced Mek1/2 activation, leading to differentially elevated Nox-1 and ROS and contributing to induction of selective apoptosis of oncogenic H-Ras-expressing cells versus counterpart cells. FK228 treatment also resulted in mitochondrial ROS production, and mitochondrial ROS contributed to Mek1/2 activation, bypassing Raf, to induce Erk1/2 activation for elevating Nox-1 and ROS, leading to apoptosis. Accordingly, Mek1/2 and Nox-1 played important pro-apoptotic roles in ROS-mediated cell death. Thus, Mek1/2 and Nox-1 should be considered as potential targets in designing therapeutic protocols using FK228 in ROS-mediated cell killing to treat cancer cells acquiring Ras activation.

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 1681. doi:10.1158/1538-7445.AM2011-1681
Abstract 1689: The combination treatments using siRNA and CDDP are effective therapeutic options for cancers
Authors: Kokuryo Toshio , Yokoyama Yukihiro , Senga Takeshi , Nagino Masato , Hamaguchi Michinari
Published: June 2012

Background: RNA interference technology has been developed as potential therapeutic options for several diseases, including cancer. Short interfering RNA (siRNA) is the best candidate for cancer therapy because of its specificity and efficiency in gene-specific silencing. We reported that the efficiency of siRNA as novel therapeutic agents for several cancers, such as cholangiocarcinoma, breast cancer and colorectal cancer.

Methods: We examined the effect of a combination treatment using Nek2 (NIMA related kinase 2) siRNA with anti cancer agent, CDDP (Cisplatin) on xenograft colorectal cancer mouse model. We next examined the effect of a combination treatment using Tlk1 (Tousled like kinase 1) siRNA with CDDP on MTT assay and TUNEL assay on cholangiocarcinoma cell lines.

Results and Discussion: The combination treatment using Nek2 siRNA and CDDP suppressed the tumor growth in colorectal cancer model, more efficiently than negative control siRNA and CDDP. It was more effective than the treatment with Nek2 siRNA alone. The combined administration of Tlk1 siRNA and CDDP strongly induced apoptosis in comparison with negative control siRNA and CDDP on cholangiocarcinoma cell lines. Tlk1 siRNA enhanced DNA damage induced by CDDP treatment. The combination of siRNA and CDDP was effective therapeutic options in colorectal cancer and cholangiocarcinoma.

Conclusions: Our data provides a strong rationale for the further investigation concerning the combination of both siRNA and anti cancer drug as a new cancer strategy, holding the potential to provide regression of multiple human malignancies.

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 1689. doi:10.1158/1538-7445.AM2011-1689
Abstract 1693: Mrp7 as a breast cancer resistance factor
Authors: Domanitskaya Natalya , Jacobs Joely , Paulose Chelsy , Hopper-Borge Elizabeth
Published: June 2012

Breast cancer is the most common cancer and the second leading cause of cancer deaths in American women. Breast cancer kills more than 40,000 women every year in the United States. Taxanes and epothilone B are used to treat breast cancer, but cellular resistance to chemotherapeutic agents is a major obstacle. Therapy-induced overexpression of ATP-binding cassette (ABC) drug efflux pumps promotes resistance in many drug-treated cancers. While early studies focused on overexpression and activity of the P-glycoprotein (Pgp) pump, a structurally distinct group of ABC efflux pumps, known as the Multidrug Resistance Proteins (MRPs), have been gaining increasing attention as alternative sources of resistance. There are 9 MRP family members (MRP1-9), with each family member preferentially transporting somewhat overlapping groups of substrates. We have previously shown that MRP7 is distinct from other MRPs because MRP7 confers resistance to a wide variety of anticancer agents including taxanes, vinca alkaloids and nucleoside-based analogs. We also have evidence that Mrp7 null mice are sensitized to taxanes (submitted). We bred a mammary tumor model to our Mrp7 null mouse to investigate Mrp7's in vivo activities regarding breast cancer resistance mechanisms. To better understand the resistance mechanisms of MRP7 the expression level of Mrp7 and expression levels of other transporters was determined in these cell lines using qRT-PCR. In addition, cell lines derived from mammary tumors are being evaluated to determine the impact Mrp7 has on sensitization to agents used in the treatment of breast cancer: epothilone B, docetaxel and paclitaxel. Further, the growth properties of these mammary tumor cell lines will be characterized. Lastly, to better understand the physiological role of this efflux pump, MRP7 cellular localization and polarity are being investigated.

Further research into previously mentioned aims and specific MRP7 inhibitors will aid in combating cellular resistance to chemotherapeutic agents.

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 1693. doi:10.1158/1538-7445.AM2011-1693
Abstract 1695: Relationship between expression of ATP-binding cassette (ABC) transporters (ABCB1, ABCC1, ABCG2) and breast cancer subtypes
Authors: Yamada Akimitsu , Ishikawa Takashi , Kimura Mariko , Shimizu Daisuke , Tanabe Mikiko , Chishima Takashi , Kondo Keiichi , Sasaki Takeshi , Endo Itaru
Published: June 2012

Background: Response to chemotherapy differs between intrinsic subtypes, luminal A, luminal B, HER2-enriched, and basal-like type. However, mechanisms of the difference are not known. Several ATP-binding cassette (ABC) transporters including ABCB1 (MDR/P-gp), ABCC1 (MRP) and ABCG2 (BCRP) have been reported to be associated with chemosensitivity.

Aim: The expression of the ABC transporters was comprehensively analyzed with respective to breast cancer subtypes.

Patients and methods: Tissue microarray (TMA) was constructed by acquiring 5.0mm cores from representative area of surgical specimens of 219 breast cancer cases. Immunohistochemistry was performed with anti ABCB1 (C219), ABCC1 (MRPr1), and ABCG2 (BXP-21), and also estrogen receptor (ER) and progesterone receptor (PgR) and Human Epidermal Receptor Growth Factor 2 (HER2).

Results: TMA revealed that 219 cases were divided into Luminal A 152(69.4%), Luminal B 13 (6.0%), HER2 18(8.2%), Triple negative 36 (16.4%). ABCB1 expression was detected in 32.4% (71/219) of the patients, and was detected 36.8%, 30.8%, 27.8%, and 16.7% in Luminal A, Luminal B, HER2, Triple negative subtypes, respectively (Luminal A vs Triple negative, p=0.03). ABCC1 (MRP) expression was detected in 23.9% (52/219) of the patients and was detected 18.7%,45.5%,14.3%, and 47.8 %, in Luminal A, Luminal B, HER2, Triple negative subtypes, respectively (n.s).

Conclusion: The expression of ABCB1 was higher in Luminal A type than in HER2 type and Triple negative breast cancer. Although further investigation is needed, the expressions of ABC transporters may, at least in part, explain the differences of chemosensitivity among subtypes.

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 1695. doi:10.1158/1538-7445.AM2011-1695
Abstract 1702: S-adenosyl-L-methionine induces P-glycoprotein overexpression and drug resistance in human cancer cells
Authors: Tsang Tsun Yee , Yeung Chi Lam Au , Yau Pak Lun , Kwok Tim Tak
Published: June 2012

P-glycoprotein (Pgp) overexpression is frequently associated with multidrug resistance in cancer cells. Pgp is an efflux pump and is encoded by human mdr1 gene. The expression of mdr1 may be regulated by promoter methylation catalyzed by DNA methyltransferases (DNMTs). S-adenosyl-L-methionine (SAMe) is an important cofactor of DNMTs. Although SAMe has been shown to regulate promoter methylation of various genes, the effect of SAMe on Pgp expression and chemosensitivity of cancer cells are however not known. The aim of the present study is to examine the role of SAMe in the regulation of Pgp expression and drug sensitivity of human cancer cells. By qRT-PCR and Western blot analyses, incubation with 1mg/ml SAMe for 24h was found to increase mdr1 mRNA and Pgp protein levels in human hepatocellular carcinoma HepG2 cells, human colorectal adenocarcinoma CaCO-2 cells and human leukemia Jurkat-T cells. Methylation specific PCR and bisulfite DNA sequencing analyses revealed that the SAMe treatment induces hypomethylation of mdr1 promoter. Moreover, SAMe decreased intracellular doxorubicin accumulation and increased doxorubicin resistance in human cancer cells as assessed by doxorubicin accumulation assay and MTT assay. Furthermore, in human colorectal carcinoma HCT-116 parent cells and DNMTs knock-out sublines, SAMe induced Pgp expression in HCT-116 parent and DNMT3b knock-out subline but not in DNMT1 and DNMT1/DNMT3b double knockout sublines. The results from the present study therefore suggest that SAMe induces hypomethylation of mdr1 promoter, Pgp expression, and thus drug resistance in human cancer cells. Furthermore, DNMT1 appeared to be important in the effect of SAMe on mdr1.

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 1702. doi:10.1158/1538-7445.AM2011-1702
Abstract 1706: Microarray analysis of gene expression reveals that several mTOR related genes are upregulated in cisplatin resistant ovarian cancer cells
Authors: Valiyeva Fatma , Suarez Erick , Gaibi Ashla , Lopez Julio , Sebastian Moises , Flores Josean , Vivas-Mejía Pablo E.
Published: June 2012

The mTOR pathway plays a central role in regulating protein synthesis, ribosomal protein translation, and cap-dependent translation. Recently, also mTOR signaling has been implicated not only in tumor development, but also in drug resistance against chemotherapy and radiotherapy. The mTOR pathway has emerged as an important cancer therapeutic target, principally with rapamycin and its derivatives. However the use of these mTOR inhibitors has been hampered because many cancer cells are resistant to these compounds. Cisplatin has been the most active drug for the treatment of ovarian cancer for almost 40 years. Although the majority of patients with ovarian cancer respond to front-line platinum combination chemotherapy the majority will develop disease that becomes resistant to cisplatin. The exact mechanism of cisplatin resistance is presently unknown. We performed growth inhibition experiments and found that the A2780CP20 human ovarian cancer cell line, which is resistant to cisplatin was also resistant to rapamycin and its analogs. Opposite, the cisplatin-sensitive counterpart, A2780PAR cell line was very sensitive to these compounds. Short-term treatment (4-hr) of A2780PAR cells with temsirolimus also induced long-term growth inhibitory effects as observed with a colony formation assay. Microarray analysis of gene expression showed that several survival related genes are up-regulated in A2780CP20 compared with the A2780PAR ovarian cancer cells. Current studies with small interference RNA (siRNA) will determine whether silencing of some candidate genes will sensitize cisplatin resistant ovarian cancer cells to rapamycin treatment.

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 1706. doi:10.1158/1538-7445.AM2011-1706
Abstract 1707: Establishment and characterization of pemetrexed-resistant lung cancer cell lines
Authors: Zhang Dan , Ochi Nobuaki , Takigawa Nagio , Chen Yanyan , Tanimoto Yasushi , Ichihara Eiki , Hotta Katsuyuki , Tabata Masahiro , Tanimoto Mitsune , Kiura Katsuyuki
Published: June 2012

Purpose: Pemetrexed (PEM), a multitargeted antifolate with manageable toxicity, is a most active drug against non-squamous non-small cell lung cancer (NSCLC); however, a majority of patients acquired the resistance to PEM eventually. To elucidate the mechanisms of acquired resistance to PEM, we established eight PEM-resistant NSCLC cell lines.

Method: PC-9 and A549 cells (adenocarcinoma of the lung) were treated with step-wise increasing concentrations of PEM. Sublines, which were able to grow in the presence of low and high concentrations of PEM, were cloned with limiting dilutions and designated PC-9/PEML and PC-9/PEMH, respectively; A549/PEML and A549/PEMH, respectively. Growth inhibition was defined by MTT assay. Thymidylate synthase (TS), dihydrofolate reductase (DHFR), glycinamide ribonucleotide formyltransferase (GARFT) and multidrug resistance-associated protein 4 (MRP4) gene expressions and protein expressions were analyzed by quantitative reverse transcriptase PCR and immunoblotting.

Result:Characteristics of PEM-resistant sublines are shown in the Table. All resistant sublines showed cross-resistant to cisplatin but not to docetaxel, vinorelbine, 5-fluorouracil and the active metabolite of irinotecan (SN-38). TS mRNA expression was significantly increased in all resistant sublines compared to the parent cells. TS mRNA expression was paralleled to the increment of TS protein. DHFR was significantly increased in the PEM-resistant A549 sublines. GARFT was not correlated with resistance to PEM. MRP4 was increased in PC-9/PEMH and A549/PEMH sublines.

Conclusions: PEM-resistant NSCLC may be still sensitive to docetaxel, vinorelbine, 5-fluorouracil and irinotecan. High TS expression seems to be the primary resistant mechanism to PEM. MRP4 and DHFR expression might be elevated at higher resistance to PEM.

Relative resistance (R.R.) was defined as the ratio of 50% inhibitory concentration (IC50) of resistant cells to IC50 of parent cells; *p<0.05; **p<0.01.

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 1707. doi:10.1158/1538-7445.AM2011-1707
Abstract 1711: Establishment and characterization of docetaxel resistant prostate cancer cell lines
Authors: Puhr Martin , Oh Su Jung , Erb Holger , Cavarretta Ilaria T. , Hobisch Alfred , Culig Zoran
Published: June 2012

Introduction: For treatment of castration-refractory prostate cancer (CRPC) patients a systemic chemotherapy and a second line hormone therapy have been developed in the last years. The administration of the chemotherapeutic drug docetaxel in combination with prednisone given to patients with CRPC on the basis of its improved survival, pain reduction, PSA response, and quality of life is the state of the art treatment at the moment. However, many patients do not respond to docetaxel or develop a resistance during treatment. Due to the low overall response survival of the patient is prolonged just for a few months. Until now, not much of molecular characteristics for docetaxel resistance is known in prostate cancer. Therefore, the main aim of the study was the establishment and characterization of docetaxel resistant cell lines. For this reason we generated docetaxel resistent sub cell lines of DU-145 and PC3 cells, which are considered models for an advanced disease.

Methods: PC3 and DU-145 cells were treated with increasing concentrations of docetaxel (up to 12,5nM). The resistance of the newly established sub lines was determined by testing cell viability, proliferation, apoptosis, and cell cycle regulation with MTT, [3H]thymidine incorporation assay and FACS measurement, respectively.

Results: Treatment of parental PC3 and DU-145 cells with 12,5nM docetaxel up to 4 days leads to a significant decrease in cell viability. An increase of cleaved PARP protein after 48h for DU-145 and after 72h for PC3 cells could confirm this observation. In contrast to parental cells, the newly established PC3-DR and DU-145-DR docetaxel resistant cells have a different cell morphology. Treatment with docetaxel did not result in increased cPARP levels. Moreover, we could not detect a significant difference in proliferation, basal apoptosis and cell cycle regulation in a direct comparison between parental PC3 and PC3-DR cells. DU-145-DR cells showed a slight increase in apoptosis and a significant decrease in proliferation after docetaxel treatment. However, we still observed a higher viability compared to parental DU-145 cells treated with 12.5nM docetaxel.

Conclusions: The generated sub lines are less sensitive to docetaxel compared to the parental cells. However, DU-145-DR cells are more sensitive to docetaxel than PC3-DR cells. Taken together, we report on successful establishment and characterization of docetaxel-resistant PC3 and DU-145 cells. These cells represent a promising cellular model to investigate the responsible molecular mechanism for docetaxel resistance in prostate cancer cells in vitro.

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 1711. doi:10.1158/1538-7445.AM2011-1711
Abstract 1714: Chemoresistance in patients with papillary serous carcinoma of the ovary
Authors: Kerr Elizabeth H. , Frederick Peter J. , Oelschlager Denise K. , Amm Hope , Sellers Jeffery , Della Manna Debbie , Buchsbaum Donald J. , Grizzle William E. , McNally Lacey R.
Published: June 2012

The majority of patients with ovarian carcinoma present at an advanced stage, with metastatic disease throughout the peritoneal cavity. Therefore, patients commonly undergo platinum-based chemotherapy. Even though the initial response rates can be high, the majority of patients will have recurrent disease and the 5-year survival rate is only 10-20%. The human lung resistance protein (LRP) is a multidrug resistance protein that has been shown to be overexpressed in models of chemotherapy resistance, but has not been adequately explored in platinum-resistant epithelial ovarian cancer (EOC). The primary aim of this study was to compare LRP expression in the tumor cells from ascitic fluid with tumor cells from omental metastasis in chemotherapy-naïve patients with advanced EOC. The secondary aim was to explore possible mechanisms in which LRP might cause drug resistance.

After IRB approval, patient ascites and metastatic implants were collected and evaluated for platinum sensitivity and expression of LRP, phospho-ERK, and AKT using western blots and immunohistochemistry (IHC). Both ascites and omental metastatic implants were treated with 50 uM carboplatin for 48 hours and cell viability was analyzed. LRP, phospho-ERK, and AKT were analyzed using IHC on samples treated with 50 uM carboplatin or phosphate buffered saline.

Of 20 patients who had matched ascites and omental metastatic implants adequate for analysis, 4 were platinum resistant, 3 were platinum sensitive, and 13 displayed intermediate platinum sensitivity. Overall, the malignant cells in ascites were more resistant to carboplatin than the metastatic implants (p=0.001) and the malignant cells in ascites showed higher expression of LRP than the omental metastatic implants by IHC and western blotting. IHC and western blotting also demonstrated that the malignant cells in ascites had lower expression of phospho-ERK and higher expression of AKT than the metastatic implants. After treatment with 50 uM carboplatin, the platinum resistant patients had decrease in phospho-ERK and an increase in AKT versus the platinum sensitive patients who had an increase in phopho-ERK and a decrease in AKT and LRP. High expression of LRP in the tumor cells in ascitic fluid may indicate platinum resistance prior to initiation of platinum-based chemotherapy. Also, changes in phospho-ERK and AKT following platinum based therapy may indicate the extent of response of EOC to this therapy.

Supported in part by the Kaleidoscope of Hope ovarian cancer foundation.

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 1714. doi:10.1158/1538-7445.AM2011-1714
Abstract 1722: Multidrug resistant P-glycoprotein mediates through Src-EGFR cascade to attenuate DNA-PK-mediated DNA repair
Authors: Lee Pei-Chih , Su Tsann-Long , Lee Te-Chang
Published: June 2012

We have synthesized several novel bifunctional alkylating derivatives of 3a-aza-cyclopenta[a]inden (BO-1012, BO-1005, BO-1099, and BO-1101) and demonstrated that they were more cytotoxic to multidrug resistant (MDR) cells, such as KBvin10, KBtax50, and CEM/VBL, than their parental cells. Using xenograft model, we confirmed that BO-1012 was more effective to suppress the growth of MDR KBvin10 cells in nude mice than to the parental KB cells. To explore the possible mechanism, we revealed that KBvin10 and CEM/VBL MDR cells have significantly lower repair activity than KB and CEM parental cells. Our results also showed that reduced repair activity in KBvin10 cells was likely due to the defective in translocation of DNA-PK, a component of repair machinery of non-homologous end-joining, from cytosol into nucleus. Furthermore, we found that BO-1012 could activate Src kinase and trigger nuclear transport of EGFR in parental cells but not in MDR cells. Inhibition of Src resulted in suppression of BO-1012-induced EGFR translocation and consequently sensitized the parental cells to BO-1012. On the contrary, Src activation induced by BO-1012 was revived in MDR cells by using siRNA to reduce the expression of P-glycoprotein (P-gp). Meanwhile, P-gp silencing also facilitated the EGFR translocation and DNA repair in MDR cells treated with BO-1012. Taken together, our results demonstrated that overexpression of P-gp in MDR cells mediates through inhibition of Src-EGFR pathway to attenuate the DNA-PK-mediated repair.

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 1722. doi:10.1158/1538-7445.AM2011-1722
Abstract 1734: MEK1/2 inhibitors AS703026 and AZD6244 may be potential therapies for KRAS mutated colorectal cancer that is resistant to EGFR monoclonal antibody therapy
Authors: Yoon Juyong , Koo Kyoung-Hwa , Choi Kang-Yell
Published: June 2012

EGFR monoclonal antibodies (mAbs) are used widely to treat metastatic colorectal cancer (mCRC) patients, but it is now clear that patients harboring K-ras mutation are resistant to EGFR mAbs such as cetuximab (Erbitux) and panitumumab (Vectibix). For this reason, current recommendations for patient care involve diagnosing the K-ras mutational status of patients prior to EGFR mAb therapy. In this study, we investigated the ability of two MEK inhibitors currently in clinical trials, AS703026 and AZD6244, to address the challenge posed by the resistance of K-ras mutated colorectal cancers to EGFR mAb. AS703026 and AZD6244 were tested in various cell-based assays and tumor xenograft studies, focusing on isogenic human colorectal tumor cell lines that expressed only WT or mutant K-Ras (D-WT or D-MUT). The EGFR mAb cetuximab inhibited the Ras-ERK pathway and proliferation of D-WT cells in vitro and in vivo, but it did not inhibit proliferation of D-MUT cells in either setting. In contrast, AS703026 and AZD6244 effectively inhibited the growth of D-MUT cells in vitro and in vivo by specific inhibition of the key MEK downstream target kinase ERK. Inhibition of MEK by AS703026 or AZD6244 also suppressed cetuximab-resistant colorectal cancer cells attributed to K-ras mutation both in vitro and in vivo. Our findings offer proof-of-concept for the use of MEK inhibitors as an effective therapy in K-ras mutated CRC.

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 1734. doi:10.1158/1538-7445.AM2011-1734
Abstract 1735: Silencing survivin splice variant 2B leads to antitumor activity in taxane-resistant ovarian cancer
Authors: Rodriguez-Aguayo Cristian , Vivas-Mejia Pablo E. , Han Hee-Dong , Shahzad Mian M.K. , Valiyeva Fatma , Shibayama Mineko , Chavez-Reyes Arturo , Sood Anil K. , Lopez-Berestein Gabriel
Published: June 2012

Survivin, a protein highly expressed in human cancers is involved in both control of cell cycle progression and inhibition of apoptosis. Transcription of the survivin gene locus (BIRC-5) yields at least 5 alternative splice variants including survivin wild-type (WT), survivin ΔEx3, survivin 2B, survivin 3B, and survivin 2α. Here, we studied the role of survivin and its splice variants in taxane-resistant ovarian cancer. Taxane-resistant ovarian cancer cells express higher survivin mRNA levels than their taxane-sensitive counterparts. Survivin 2B expression was significantly higher in taxane-resistant compared to sensitive cells. Small-interference RNAs (siRNAs) targeting survivin were designed to silence all survivin splice variants (T-siRNA) or survivin 2B (2B-siRNA). Silencing survivin 2B induced growth inhibitory effects similar to silencing total survivin in vitro. In addition, survivin 2B siRNA incorporated into DOPC nanoliposomes resulted in significant reduction in tumor growth (p<0.05) in the HeyA8.MDR and SKOV3.TR models, and these effects were similar to T-siRNA-DOPC. The anti-tumor effects were further enhanced in combination with docetaxel chemotherapy (p<0.01). Finally, we found a significant association between survivin 2B expression and progression free survival in 117 epithelial ovarian cancers obtained at primary debulking surgery. These data identify survivin 2B as an important target in ovarian cancer, and provide a translational path forward for developing new therapies against this target.

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 1735. doi:10.1158/1538-7445.AM2011-1735
Abstract 1789: Auristatin-based antibody-drug conjugates are synergistic in combination with PI3K-AKT-mTOR pathway inhibitors in hematologic malignancies and carcinoma
Authors: Lewis Timothy S. , McCormick Renee S. , Zeng Weiping , Miyamoto Jamie B. , Kennedy Dana , Sievers Eric L. , McEarchern Julie A. , Law Che-Leung
Published: June 2012

Antibody-drug conjugates (ADCs) that couple the potent anti-mitotic agents monomethyl auristatin E or F (MMAE or MMAF) to tumor antigen specific monoclonal antibodies have demonstrated antitumor activity in preclinical models. We report that the combination of auristatin-based ADCs with inhibitors of the phosphoinositide 3-kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) signaling pathway improves cytotoxic activity in Hodgkin lymphoma (HL), non-Hodgkin lymphoma (NHL), and renal cell carcinoma (RCC) cell line models. Implicated in tumor cell growth and survival, the PI3K-AKT-mTOR pathway is frequently hyperactivated in carcinomas and hematologic malignancies with elevated AKT activity reported in ∼64% of Hodgkin Reed-Sternberg (HRS) cells and 25-52% of primary patient diffuse large B-cell lymphomas. We produced dose response curves for auristatin ADCs and PI3K-AKT-mTOR pathway inhibitors, alone and in combination, and then performed combination index (CI) analysis using the Chou-Talalay method. The CD30-targeting ADC brentuximab vedotin (SGN-35) and the CD19-targeting ADC (SGN-19A) were synergistic (CI < 0.7) with the allosteric mTORC1 inhibitors sirolimus and temsirolimus in panel of lymphoma cell lines. Similarly, a CD70 targeting ADC (SGN-75) was synergistic with sirolimus and temsirolimus in RCC cell lines. Unconjugated MMAE drug was synergistic in combination with sirolimus and temsirolimus, proving the auristatin component of the ADC is responsible for enhanced combinatorial activity. Next, we found that brentuximab vedotin, SGN-19A, and SGN-75 were each synergistic with NVP-BEZ235, a dual specificity PI3K and mTORC1/2 catalytic site inhibitor. Therefore, the synergy observed with auristatin ADCs is generalizable to inhibitors of the PI3K-AKT-mTOR pathway and not unique to rapamycin analogs. Finally, the brentuximab vedotin combination with temsirolimus was evaluated in a L428 mouse xenograft model of B-like HL. Temsirolimus and brentuximab vedotin alone showed antitumor activity in the L428 model; however, the brentuximab vedotin plus temsirolimus combination had significantly greater (P-value = 0.001) antitumor activity than either drug alone. The mechanism for the synergy observed in these combinations may involve reduced expression of antiapoptotic proteins by mTOR pathway inhibitors, which sensitizes cancer cells to auristatin ADCs. Collectively, these data suggest the potential for auristatin ADC plus mTOR inhibitor cotherapy in PI3K-AKT-mTOR pathway hyperactivated lymphomas and carcinomas.

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 1789. doi:10.1158/1538-7445.AM2011-1789
Abstract 179: Histone deacetylase inhibitor; CG005, is a novel anticancer drug; as a combination drug with docetaxel in prostate cancer
Authors: Kim Yong Sook , Kim Mi Joung , Choi Jene , Jang Sejin , Lee Je-hwan , Ro Seonggu , Kim Choung-soo , Hwang Jung Jin
Published: June 2012

We synthesized a novel hydroxamate-based HDACi, CG0005 {(E)-2-(Naphthalen-1-yloxymethyl)-oct-2-enedioic acid 1-[(3-dimethylamino-propyl)-amide] 8-hydroxyamide]}. Like other inhibitors, for example SAHA and PXD 101, CG0005 has the hydroxamic acid moiety to bind zinc at the bottom of catalytic pocket. The aliphatic chain of CG0005, which is presumed to be positioned at the narrow channel of pocket, is less flexible than that of SAHA and less rigid than that of PXD101. Of the other moieties, the tertiary amine was adopted to improve water solubility. Firstly, we analyzed its activity in hormone-dependent LNCaP cells and hormone-refractory DU145 and PC3 cells. CG0005 inhibited deacetylation of histone3 and tubulin as much as vorinostat and belinostat. CG0005 also inhibited growth of prostate cancer cells and increased sub-G1 population and activated caspase-9, -3 and -8. These results indicated that CG0005 induced apoptosis in prostate cancer cell lines. Next, we examined the effect of CG0005 on cell death induced by docetaxel in DU145 cells in vitro and in vivo. Pre-treatment of DU145 cells with docetaxel followed by CG0005 showed synergistic cytotoxicity, and increased the apoptotic sub-G1 population, caspase activation, and tubulin acetylation, compared with docetaxel alone. Moreover, the combination treatment decreased Mcl-1, Bcl-xl and cyclin D1. Docetaxel and CG0005 combination reduced tumor size in the DU145 xenograft model. These preclinical results show that post-treatment with CG0005 potentiated anti-tumor effect of docetaxel in hormone-refractory prostate cancer (HRPC) cells via intrinsic and extrinsic apoptotic pathway in vitro and in vivo.

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 179. doi:10.1158/1538-7445.AM2011-179
Abstract 1804: Immuno-chemoradiotherapy for oral cancer: Augmentation of OK-432-induced anti-tumor immunity by tegafur and radiation
Authors: Okamoto Masato , Tano Tomoyuki , Shin Kan , Mitsunobu Sato
Published: June 2012

In the current study, we have evaluated the anti-cancer effect of OK-432 in combination with UFT, an oral preparation combining the 5-FU pro-drug tegafur and uracil in a 1:4 ratio, and radiation therapy (RT). RT+UFT+OK-432 therapy elicited better clinical response and longer survival time than only RT+UFT. Next, we conducted the in vitro study to examine the effect of 5-FU and X-ray irradiation in the OK-432-induced cytokines. Human peripheral blood mononuclear cells (PBMCs) were stimulated with OK-432, 5-FU or X-ray for 24 hr. OK-432 induced Th1-type cytokines (IFN-γ, IL-12, IL-18) as well as IL-10 and TGF-β. When PBMCs were stimulated by 5-FU and/or X-ray in combination with OK-432, production of IL-10 and TGF-β was significantly inhibited. Gene expression of negative regulators, SOCS-1 and -3, was augmented by OK-432, however, this was also inhibited by 5-FU and X-ray irradiation. OK-432-induced IL-10 and TGF-β, but not Th1-type cytokines, was significantly reduced by addition of antisense oligonucleotide for SOCS-1 or that for SOCS-3. Radiation and 5-FU induce Th1-dominant state by inhibiting the OK-432-induced production of IL-10 and TGF-β mediated by regulation of negative regulators, SOCS-1 and -3.

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 1804. doi:10.1158/1538-7445.AM2011-1804
Abstract 1806: TLR2 agonist PSK activates NK cells and enhances the anti-tumor effect of HER2-targeted monoclonal antibody therapy
Authors: Lu Hailing , Yang Yi , Gad Ekram , Disis Mary L.
Published: June 2012

Purpose: The therapeutic effect of trastuzumab, the anti-HER2 monoclonal antibody (mAb), is dependent on functional NK cells which mediates antibody-dependent cell-mediated cytotoxicity (ADCC). Novel agents that enhance NK cell function could potentially improve the therapeutic effect of trastuzumab. We recently identified polysaccharide krestin (PSK), a natural product extracted from medicinal mushroom, as a novel TLR2 agonist. The current study was undertaken to evaluate the effect of PSK on human NK cells and the potential of PSK to enhance HER2-targeted mAb therapy.

Experimental Design: Human PBMC were stimulated with PSK to evaluate the effect of PSK on NK cell activation and IFN-g secretion. K 562 was used as a target to measure the lytic function of NK cells. Effect of PSK on ADCC was also measured using trastuzumab-coated SKBR3 and MDA-MB-231 breast cancer cells. Finally, in vivo experiment in neu transgenic mice was carried out to determine the potential of PSK to augmented HER2-targeted mAb therapy.

Results: PSK upregulated the expression of activation markers, CD25 and CD69, on NK cells, and stimulated IFN-g production by NK cells. The cytolytic potential of NK cells, as shown by CD107a degranulation and lysis of K562, was also augmented by PSK treatment. PSK enhanced trastuzumab-mediated ADCC in lysing both SKBR3 and MDA-MB-231 breast cancer cells. In vivo treatment in neu transgenic mice showed that oral administration of PSK significantly potentiated the anti-tumor effect of anti-rat neu/HER2 mAb therapy.

Conclusion: These results demonstrated that natural product PSK activates human NK cells and potentiates trastuzumab-mediated ADCC. Concurrent treatment of PSK and trastuzumab may be a novel way to augment the anti-tumor effect of trastuzumab.

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 1806. doi:10.1158/1538-7445.AM2011-1806
Abstract 181: The combination of a novel retinoid compound with standard chemotherapy increases cytotoxicity in an ovarian cancer cell line
Authors: Whitworth Jenny M. , Oliver Patsy J. , Muccio Donald D. , Straughn J. Michael , Buchsbaum Donald J.
Published: June 2012

Background: Retinoids are a class of chemotherapeutic agents that have been studied in a variety of malignancies and are known to play an important role in cellular proliferation and apoptosis. 9cUAB30 is a novel retinoid compound that has been shown to demonstrate anti-tumor activity in breast cancer and in acute promyelocytic leukemia. The objective of this study was to determine if 9cUAB30, alone and in combination with carboplatin, has cytotoxic effects on ovarian cancer cells.

Methods: The ovarian cancer cell line A2780 was cultured in 96-well plates for 24 hours. Carboplatin at doses of 15 and 30 µM was added 24 hours after plating (Day 1). 9cUAB30 at doses of 0.5, 1, and 3 µM was also added at 24, 72, and 120 hours after plating (Days 1, 3 and 5). On Day 7, cell viability was assessed using adenosine triphosphate (ATP) assays.

Results: Mean cytotoxic values (expressed as % of untreated control) were calculated for 9cUAB30 monotherapy. On average, 6% cytotoxicity was observed at the lowest dose (0.5 µM,) compared to 48% cytotoxicity at the medium dose (1 µM) and 66% cytotoxicity at the highest dose (3 µM). Addition of 9cUAB30 at doses of 1 and 3 µM significantly reduced cell viability (p<0.01) compared to controls. When used in combination with carboplatin (30 µM), 9cUAB30 at doses of 0.5, 1 and 3 µM resulted in 71%, 85% and 91% cytotoxicity, respectively. When used in combination with a lower dose of carboplatin (15 µM), 9cUAB30 at doses of 0.5, 1 and 3 µM resulted in cytotoxicity of 67%, 83% and 89%, respectively. Addition of 9cUAB30 to carboplatin at either 15 or 30 µM significantly reduced cell viability when compared to carboplatin alone (p<0.01).

Conclusion: In previous studies of acute promyelocytic leukemia, a dose of 5 µM 9cUAB30 was commonly used for in vitro studies. In ovarian cancer, lower doses of this novel retinoid can be used to achieve significant cytotoxicity. The combination of carboplatin and 9cUAB30 provided additional ovarian cancer cellular cytotoxicity. Further in vivo studies in ovarian cancer xenografts models are underway to determine if this novel retinoid compound enhances efficacy in combination with standard chemotherapy.

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 181. doi:10.1158/1538-7445.AM2011-181
Abstract 1812: Effects of vitamin D on obesity-induced increase in ER-positive and ER-negative mammary cancer in mice
Authors: Yu Wei , Kim Dominic , Sumis Allison , Hilakivi-clarke Leana
Published: June 2012

We have previously found that dietary exposure to vitamin D (VD3) reverses the increase in endometrial cancer in obese Pten+/- mice. Since obesity also increases breast cancer risk and recurrence, this study investigated whether VD3 supplementation may inhibit development of mammary cancer in obese mice. As the protective effect of VD3 in the endometrium was not related to the estrogen receptor (ER), we pursued another potential pathway and determined whether VD3 reverses obesity-induced insulin resistance. Methods: Two mouse models were used: DMBA-treated C57BL/6 mice developing ER positive (ER+) mammary tumors, and Pten+/- mice which develop triple negative mammary tumors. C57BL/6 mice were wild type littermates of the Pten+/- mice. Mice in the two models were divided into four groups after weaning, and they were fed (a) AIN93G based control diet, (b) diet supplemented with 20K IU VD3, (c) obesity-inducing diet (OID), or (d) OID supplemented with 25K IU VD3. Results: OID induced insulin resistance and increased mammary tumorigenesis in both C57BL/6 and Pten+/- mice. VD3 significantly inhibited ER+ (p<0.05) and ER- (p<0.04) mammary cancer, but did not reverse the obesity-induced increase in cancer risk. Results obtained in the insulin tolerance test, however, indicated that VD3 prevented the development of insulin resistance in the OID fed obese C57BL/6 and Pten+/- mice. Conclusions: Dietary exposure to VD3 protects against development of ER+ and triple negative mammary cancer, but only in lean mice. VD3 supplementation also prevents insulin resistance in obese mice, but this is not sufficient to reduce mammary cancer risk in either C57BL/6 or Pten+/- mice

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 1812. doi:10.1158/1538-7445.AM2011-1812