bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2564: High-throughput siRNA library screen for discovery and identification of new melanoma therapeutic targets in combination with antioxidant pretreatment
Authors: Deng Wuguo , Poindexter Nancy J. , Ekmekcioglu Suhendan , Kwon John , Kinney Sandra A. , Grimm Elizabeth A.
Published: February 2011

Melanoma is one of the most prevalent cancers in the United States, having the fifth highest cancer incidence in males and sixth highest incidence in females. Primary cutaneous melanoma can often be cured by surgery, but for those patients in whom metastasis has occurred, mortality is high in part due to numerous chemoresistance mechanisms. Thus, there is an urgent need to discover and identify novel therapeutic targets for the efficient treatment of this lethal disease. Gene silencing by RNA interference (RNAi) is a powerful tool to identify novel genes involved in specific biological processes. In our study, we used high-throughput druggable siRNA library (Dharmacon) targeting 6028 human genes to screen metastatic melanoma cell lines and found that knockdown of gene expression by siRNA pools targeting 885 genes significantly inhibited melanoma growth (p<0.005). Among them, 67 siRNA pools resulted in >50% inhibition of cell viability in the melanoma A375 cells which we employed for the screening analysis. We validated the top-six cancer-related genes (RRM2, BCAR3, PSMA2, UBB, RRM1, TCP1) as potential melanoma therapeutic target candidates, as knockdown of these 6 genes significantly inhibited cell growth and induced apoptosis in multiple melanoma cell lines. We have hypothesized that antioxidant treatment relieves resistance mechanisms, and showed that among the screened >6000 siRNA pools, treatment with 20 pools significantly increased the growth inhibition in the presence of nontoxic levels of bardoxolone methyl (p<0.005), a novel semi-synthetic triterpenoid (previously known as CDDO-Me) with potent antioxidant activity generously provided by Reata Pharmaceuticals. We also selected 5 additional cancer-related genes (GNPAT, SUMO1, SPINT2, FLI1 and SSX1) for further analysis and validated them as additional candidates for therapeutic targeting in the presence of antioxidant. Our results thus demonstrate the feasibility of the high-throughput siRNA library screen system in discovering new melanoma therapeutic targets and shows that these new candidate genes are promising for the development of novel therapeutic targets for melanoma treatment, many of which are revealed by antioxidant pretreatment. Results from our study provide the basis for significant advances in identifying targets for the treatment of melanoma patients. (This study was partially supported by the grant from the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation and the NIH Melanoma SPORE grant P50, CA093459).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2564.
Abstract 2565: Targeting the p38 MAPK pathway inhibits drug resistance in colon adenocarcinoma cells
Authors: Paillas Salomé , Boissière Florence , Causse Annick , Denis Vincent , Vezzio-vie Nadia , Arsa Imade Ait , Martineau Pierre , Bibeau Frederic , Rio Maguy Del , Gongora Céline
Published: February 2011

Despite the recent advances achieved in the treatment of colon cancer, tumour resistance is a frequent cause of chemotherapy failure. Our work was aimed to determine the molecular mechanisms involved in the resistance to irinotecan (SN38), an anticancer agent widely used in colorectal cancer treatment. To this end, we have established an SN38-resistant cellular model from the colon adenocarcinoma cell line HCT-116 and we have obtained 5 resistant clones. In all these five clones we have observed an activation of the MAPK p38 compared to the sensitive cell line called HCT116-s. We have shown in the HCT116-SN6 clone that the p38 pathway is responsible for the resistance to SN38. The family of MAPK p38 counting four isoformes α, β, γ and δ, we have generated cells lines overexpressing each isoforms or inhibiting each isoform expression, and we have demonstrate that the α and β forms are involved in SN38 resistance. In a xenograft model we have shown that the HCT116-SN6 cell line is also resistant to Campto treatment in vivo, and that the α and β isoforms are still responsible for drug resistance. Finally, we have also detected phosphorylated p38 in colon cancer cells of patients resistant to Irinotecan-based chemotherapy. These results show for the first time that the p38 pathway is implicated in the drug sensitivity of colon cancer cells and that targeting p38 could be a good alternative to decrease drug resistance.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2565.
Abstract 2569: Disruption of ceramide glycosylation restores p53-dependent apoptosis in p53 mutant drug-resistant cancer cells: Alternative splicing determines the feature of p53 activity
Authors: Patwardhan Gauri A. , Gupta Vineet , Hsia Shaochung , Gu Xin , Jazwinski Michal , Liu Yong-Yu
Published: February 2011

Mutation of tumor suppressor p53 is frequently detected in many different types of cancers. p53 mutants acts as oncogenic proteins preventing programmed cell death and promoting cancer progression. Restoration of p53 that is to increase the expression of wild-type p53 and to eliminate mutant expression can substantially increase the efficacy of chemotherapy and stop malignant progression. However, incomplete understanding the molecular mechanism underlying p53 gene regulation limits the success in p53 restoration. We, for the first time, report that disruption of ceramide glycosylation restores p53 dependent-apoptosis in p53 mutant drug-resistant cancer cells. A lose of 21 base-pair in the mRNA of exon-5 can result in the accumulation of mutant p53 and cells insensitiveness to induced-apoptosis in human NCI/ADR-RE ovarian cancer cells. We found that treatment of mixed-backbone oligonucleotide against human glucosylceramide synthase (MBO-asGCS) increased the levels of wild-type p53 mRNA (containing the 21 bp in exon-5) and protein of wild-type p53 in dose-dependent manner (50-200 nM). In response to doxorubicin-induced DNA damage, phosphorylated p53 (Ser15 in the exon-5) was significantly increased, that in turn increased the protein levels of p21 and Bax, and apoptosis (52% vs. 3%) after MBO-asGCS treatment compared to control in NCI/ADR-RE cells. Silencing of GCS using MBO-asGCS (1 mg/kg) restored wild-type p53 expression and substantially sensitizes NCI/ADR-RE tumors to doxorubicin-induced apoptosis in vivo (10 mice per group), as compared to MBO-scramble control or other treatments. In contrast, introduction of GCS gene in NCI-ADR-RE cells reduces wild-type p53 expression and p53-depedent apoptosis. Further mechanic studies indicated that increased ceramide after GCS silencing modulates the function of SRp30a (ASF/SF2) regulating alternative pre-mRNA splicing. Increasing endogenous ceramide by inhibition of its glycosylation using PDMP or enhanced its production using sphingomylinase promoted wild-type p53 expression at the levels of mRNA, protein and phosphorylation; decreasing ceramide by inhibition of ceramide synthesis using fumonisin (FB1) repressed wild-type p53 expression. Present study indicates that cancer cells marked with mutant p53 phenotype are capable of expressing functional p53; ceramide glycosylation is one molecular mechanism that shifts expression to wild-type form of p53 at alternative splicing of post-transcription processing. MBO-asGCS, a specific agent silencing GCS restores p53-dependent apoptosis in cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2569.
Abstract 258: Molecular features and functional consequence of CD44 activation by a novel recurrent IGH translocation t(11;14) (p13;q32) in mature B-cell lymphoid neoplasm
Authors: Chen Yun-Wen , Hu Xiao-Tong , Liang Anthony C.T. , Wong Michelle L.Y. , Au Wing-Yan , Wong Kai-Yau , Choi William W.L. , Wan Thomas S.K. , Chu Kent-Man , Chim Chor Sang , Chan Li Chong , Kwong Yok-Lam , Liang Raymond H.S. , Srivastava Gopesh
Published: February 2011

Dysregulation of an oncogene by translocation to Ig locus is a common event in the pathogenesis of most non-Hodgkin's lymphoma. Using inverse-PCR, CD44 on 11p13 was identified as a novel translocation partner of IgH in 9 of 114 cases of gastric, non-gastric extranodal, follicular and nodal diffuse large B-cell lymphomas (DLBCLs) analyzed. IgHSμ/CD44 translocation juxtaposes the enhancer of IgHSμ to the 5’ regulatory region of CD44 in a tail-to-head orientation, leading to the removal of exon 1 of CD44. Sequencing analysis showed microhomology sequences at the junction breakpoints of all the IGHSμ/CD44 translocations, suggesting that these translocations were the results of illegitimate switch recombination facilitated by homologous sequences present on both chromosomes. By interphase-FISH using home-grown CD44 dual-color break-apart probes (consisting of BACs RP4-607I7 and RP4-683L5), breakage at the CD44 locus in each of the nine IGHSμ/CD44 translocation-positive cases was confirmed. By 5’ RACE analysis, fusion Iμ-CD44ΔEx1 hybrid transcripts (with a splicing of the Iμ exon upstream of Sμ to exon 2 of CD44), were identified in all the nine lymphomas with IGHSμ/CD44 translocations. Notably, these translocations were detected exclusively in GCB-type DLBCLs. However, CD44 mRNA was minimally or not expressed in CD10+ microdissected reactive GCB cells. The IGHSμ/CD44 translocation substitute Sμ for the CD44 promoter and remove exon 1 of CD44, resulting in over-expression of the Iμ-CD44 hybrid transcript which encodes for a new CD44 variant lacking leader peptide sequence but retaining a unique C-terminus (CD44ΔEx1). The Iμ-CD44ΔEx1 ORF would encode for the CD44ΔEx1 protein starting from the ATG at nucleotide 254 with strong Kozak sequence. The new CD44ΔEx1 variant showed some similarity to CD44v5, but it lacked the leader peptide. The IGHSμ/CD44 translocation was detected in patients with advanced-stage disease (stages III and IV). When overexpressed in vitro in the CD44-negative GCB-DLBCL cell line BJAB, the CD44ΔEx1-GFP was localized to the cytoplasm and nucleus, while CD44s-GFP (standard form) was localized to the plasma membrane. The ectopic expression of CD44ΔEx1 in BJAB cells enhanced the cell proliferation rate and its clonogenic ability. These findings indicate a possible pathogenic role of the recurrent translocation in several malignant B-cell lymphomas.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 258.
Abstract 2587: In vitro plasma stability of human anti-CD70 antibody drug conjugate, MDX-1203
Authors: Sung Janette , Vemuri Kavitha , Passmore David , Tatum Andrea , Kempe Tom , Brams Peter , Derwin Dan , Thevanayagam Lourdes , Srinivasan Mohan , Huber Mary , Rao Chetana , Zhang Allen , Cong Charlie , Sufi Bilal , Gangwar Sanjeev , Deshpande Shrikant , Rangan Vangipuram S.
Published: February 2011

MDX-1203 is a human anti-CD70 antibody conjugated to a pro-drug containing DNA alkylating cytotoxic Drug A. Drug A is composed of the anti-tumor compound Drug B, containing an ester linked protecting group, and a maleimide containing cleavable peptide linker designed to facilitate conjugation to the antibody. Mechanism of action of ADCs involve antibody mediated tumor specific delivery, cellular uptake, and intracellular pro-drug release and activation. Understanding the stability of the peptide linker as well as the pro-drug in various plasma matrices is critical for the development of successful ADC therapeutic. We have generated mouse monoclonal antibodies that specifically recognize either the intact Drug A or Drug A without the protecting group. Using these antibodies, an ELISA method was developed to study in vitro plasma stability of pro-drug in MDX-1203. Our results indicate that the plasma stability of ester linked protecting group varies significantly depending on the animal species probably due to variation in the level of plasma esterase activity. In order to determine the peptide linker stability, a radiolabeled MDX-1203 with 14C radiolabel on Drug A was made. A Thin Layer Chromatography method was developed to determine the in vitro plasma stability of the peptide linker in different plasma matrices. Our results indicate that the peptide linker in MDX-1203 is stable at 37o C up to 6 days. Based on these experimental data, we propose a model for stability of the peptide linker as well as the pro-drug in MDX-1203 in various plasma matrices.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2587.
Abstract 2593: Telomerase-specific oncolytic virotherapy for osteosarcoma
Authors: Kawashima Hiroyuki , Li Guidong , Ogose Akira , Endo Naoto , Kuwano Ryozo , Urata Yasuo , Fujiwara Toshiyoshi
Published: February 2011

Oncolytic adenoviruses are being developed as novel antitumor therapeutics and currently undergoing clinical trial. Telomelysin (OBP-301) is a type 5 adenovirus that contains the replication cassette in which the human telomerase reverse transcriptase promoter drives expression of the E1 genes, and shows telomerase specific replication and cell killing effect. We previously demonstrated that the expression of coxsackie-adenovirus receptor (CAR) is high in osteosarcoma compared with the other mesenchymal tumors, and moreover, many investigators have been reported that telomerase expression predicts the unfavorable outcome in osteosarcoma. The present investigation analyzed that the selective replication and antitumor effects of Telomelysin using 8 osteosarcoma and 1 normal dermal fibroblast cell lines in vitro as well as in vivo by using athymic mice carrying xenografts. At first, all cell lines were used to examine the mRNA expression of CAR and hTERT, and 3 osteosarcoma cell lines and 1 normal fibroblast cell were chosen for Telomelysin infection. Selective E1A and E1B expression were shown in osteosarcoma cells by quantitative real-time RT-PCR and Western blot analysis, but not in normal cells such as human dermal fibroblasts. Telomelysin replicated efficiently and induced marked cell death in osteosarcoma cells, whereas replication as well as cytotoxicity was highly attenuated in normal fibroblast cells lacking telomerase activity. Expression of cleaved caspase, PARP and LC-3 I, II after Telomelysin infection was tested by Western blot, however the mechanism of induction of cell death could not be revealed in this time. For in vivo evaluation, nu/nu mice xenografted with NOS10 human osteosarcoma cell received intratumoral injection of 107 plaque-forming units of Telomelysin, and resulted in a significant inhibition of tumor growth and long-term survival in all treated mice. Moreover, selective replication of Telomelysin in tumor cell was also demonstrated by anti-E1A immunohistochemistly, and induction of apoptosis was observed by TUNEL staining. Our results suggest that the hTERT promoter confers competence for selective replication of Telomelysin in osteosarcoma cells, and the outcome has important implications for tumor-specific oncolytic chemovirotherapies for human osteosarcomas.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2593.
Abstract 2595: Vesicular stomatitis virus as a treatment for colorectal cancer
Authors: Stewart John H. , Ahmed Maryam , Northrup Scott A. , Lyles Douglas S.
Published: February 2011

Introduction: Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States. Despite progress in many aspects of combating colorectal cancer, the cause of death in nearly a third of all patients is metastatic disease. Vesicular stomatitis virus (VSV) is an attractive candidate as an oncolytic virus for the treatment of CRC due to its potent ability to induce apoptosis. Our group has generated a genetically engineered recombinant VSV containing an M protein mutation (rM51R) to enhance its tumor selectivity while preserving its oncolytic effects. As an extension of these findings, we hypothesized that oncolytic VSV can effectively treat CRC cells and therefore serve as an oncolytic therapy for the treatment of metastatic CRC.

Methods: We compared the cytolytic effects of wild type (rwt) and M51R VSV in RKO, HCT116 and Lovo CRC cell lines via MTS assays. We initially sought to determine if CRC cells were susceptible to the oncolytic effects of VSV in single-cycle and multiple-cycle infection conditions. Viral protein synthesis and the production of viral progeny by CRC cell lines was quantified by S35 methionine labeling and viral plaque assays respectively. RKO tumor xenografts were established in athymic nude mice and injected with 108 pfu of M51R VSV.

Results: We found that CRC cells display differential sensitivity to oncolytic VSV. RKO and HCT116 CRC cells were very sensitive to the oncolytic effects of both rwt and M51R viruses at 48 hours after both single and multiple-cycle infections. On the other hand, Lovo cells were somewhat resistant to VSV-induced cell killing under identical treatment conditions. All CRC cell lines supported the production of viral progeny with the peak viral production occurring at 36 hours after single and multiple-cycle infections with rwt and M51R VSV. Treatment of RKO xenografts with M51R VSV resulted in stabilization of tumor size relative to untreated controls after 21 days.

Conclusions: These findings suggest that M51R VSV is a good candidate oncolytic virus for the treatment of metastatic colorectal cancer. Our future work will focus on defining the proportion of colorectal cancers that are susceptible to the oncolytic effects of VSV. In addition, we will identify molecular targets that may enhance the therapeutic efficacy of M51R VSV.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2595.
Abstract 2596: Targeted delivery of doxorubicin conjugated with anti-matriptase antibody to treat multiple myeloma
Authors: Bertino Joseph R. , Lin Siang-Yo , Lin Chen-Yong
Published: February 2011

Survival of patients with multiple myeloma (MM) has been significantly improved owing to the advances in new therapeutics for the patients in the past decade; however, the disease remains incurable. New or improved therapeutic agents are therefore urgently needed. Matriptase, a membrane-bound serine type II protease, is overexpressed in B- cell lymphoma, multiple myeloma and epithelial carcinomas. Due to the overexpression of matriptase in multiple myeloma in combination with the limited distribution of the enzyme in epithelial-containing tissues, we have designed and generated an anti-matriptase monoclonal antibody (M24) conjugated to doxorubicin (DOX) for selectively targeting MM cells. The immunoconjugate (M24-DOX) is as potent as free doxorubicin to inhibit the growth of MM cells. Significantly, bone marrow-derived mesenchymal stromal cells that do not express matriptase, were insensitive to the immunoconjugate, whereas free DOX showed cytotoxicity. More importantly, compared to free DOX, target delivery of doxorubicin by the matriptase antibody significantly reduced the toxicity toward cardiomyocytes that lack maptriptase expression. Following exposure of MM cells to M24-DOX, the immunoconjugate was rapidly internalized, and was mainly localized within nuclei. Moreover, after 24-hour incubation, over 90% of the free DOX was released from the conjugate within the cells. Targeting matriptase, expressed on myeloma cells, should increase the effectiveness and therapeutic index of doxorubicin and improve the treatment of patients with multiple myeloma.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2596.
Abstract 2600: Effect of green tea intake on pharmacokinetics of oral etoposide in cancer patients
Authors: Nagai Shunji , Fujiwara Yutaka , Ishizuka Naoki , Ishihara Mikiya , Itoh Kuniaki , Ogasawara Naomi , Nakajima Hikaru , Fuse Hiroe , Matsubara Nobuaki , Mukai Hirofumi , Yamaguchi Takeshi , Mukohara Toru , Minami Hironobu
Published: February 2011

BACKGROUND: Habitual consumption of green tea has been epidemiologically correlated with low risk of cancer. Among various constituents of green tea, catechins are experimentally suggested to have benefitial activity. Especially, (-)-epigallocatechin gallate (EGCG) is the most bioactive constituent. Decreased activation of carcinogenic compounds by inhibition CYP3A4 is proposed as one of mechanisms of anticarcinogenic effect. Green tea is one of the most popular beverages in Japan and Asian countries, and patients often take drugs with green tea beverages. Co-administration of oral cancer medicine which is metabolized by CYP3A4 with green tea may cause harmful interactions. PURPOSE: We investigated the effect of green tea beverage intake on pharmacokinetics of etoposide in an open label, single-dose, randomized, two-way crossover study. METHODS: Patients with various cancers were randomly assigned to receive an etoposide 50-mg capsule either with 600mL green tea beverage or 600mL of water, separated by at least 72-hours washout period. Blood samples were collected for 24 hours. Etoposide concentrations in plasma were determined by high performance liquid chromatography. Plasma pharmacokinetic parameters, including area under the curve (AUC), maximum concentration (Cmax) and elimination half-life (t1/2) were calculated by non-compartment analysis using WinNonlin software.

RESULTS: Twenty-five cancer patients (11 males, 14 females; median (range) age, 63 years (46 to 81 years)) participated in this study. Co-administration with green tea resulted in an unexpected decrease by 24.8% in the AUC (p= 0.0003) of etoposide (Table). Carry-over effect was denied.

CONCLUSION: Green tea reduces rather than increases exposure to orally administered etoposide.Mean pharmacokinetic parameters of etoposideParameters Water  Green teaP-valueAUC 337.61257.45P=0.0003(mg*min/ml)    Cmax (mcg/ml) 2.97252.1284P=0.0004t1/2 (h) 7.43116.7696P=0.0771

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2600.
Abstract 2603: A critical role of Gβγ in breast tumor growth and metastasis
Authors: Tang Xiaoyun , Henry Michael , Chen Songhai
Published: February 2011

A growing body of evidence indicates the involvement of G protein coupled receptors (GPCRs) in the process of breast tumor development, including tumor growth, invasion and metastasis. Targeting GPCRs has been proposed as a novel adjuvant strategy in cancer treatment. However, this approach faces many significant hurdles due in part to the involvement of multiple GPCRs in tumor progression. Thus, there is a need for an alternative approach that targets a signaling mechanism common to these receptors. GPCRs such as lysophosphatidic acid (LPA) receptors, thrombin receptors and the chemokine receptor CXCR4 transmit signals through multiple classes of heterotrimeric G proteins, which consist of Gα and Gβγ subunits. There are four major classes of Gα subunits (Gαi, Gαs, Gαq and Gα12/13) that regulate distinct activities of different effectors. Although there are 5 Gβ and 12 Gγ isoforms, different combination of Gβγ complexes appear to regulate a similar profile of downstream effectors. We therefore reason that Gβγ-dependent signaling may represent a point of signal convergence from multiple GPCRs that can be targeted for the therapeutic of breast tumor. In this study, we evaluated the role of Gβγ in breast tumor progression. Our data show that blocking Gβγ signaling with small molecular inhibitors alleviated breast tumor cell proliferation and GPCR-stimulated cell migration in vitro, suggesting that Gβγ is critical for breast tumor progression. Consistent with these findings, overexpression of Gβγ scavengers, the C-terminal tail of G protein-coupled receptor kinase 2 (GRK2-ct) or Gαt, in breast tumor cells suppressed tumor cell growth both in 2D and 3D culture, and abolished LPA- and SDF1α-stimulated cell migration. Additional studies indicate that Gβγ mediates GPCR-simulated activation of PI3K, PLCβ and MAPK, which in turn contribute to breast tumor cell growth and migration. Finally, by inducible expression of Gαt in MDA-MB-231 cells, we provided evidence that Gβγ signaling promotes tumor cell growth and lung metastasis in mouse xenograft models. Taken together, our data demonstrate that Gβγ plays a critical role in breast tumor progression. These findings suggest that targeting Gβγ-dependent signaling may represent a novel therapeutic approach for breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2603.
Abstract 2611: Cisplatin negatively affects CNS progenitor cells and behavior in the adult mouse
Authors: Ana Nunes T. , Han Ruolan , Sprentall Kelcie , Santoni Ornella , Noble Mark
Published: February 2011

Patients that are treated with chemotherapy exhibit long term changes in cognitive function, decreasing quality of life (Van Dam et al 1998). Although much work has been done characterizing these changes in the patient, there is little research on the possible cellular changes. Additionally, little has been done studying the effects of a single chemotherapeutic agent on cognitive function. Our laboratory has previously shown that chemotherapy, including cisplatin, decreases neural progenitor cell division and increases cell death in the mouse brain (Dietrich et al 2006; Han et al., 2008). Here, we have studied the effects of cisplatin on CNS progenitor cells and also on behavior. We found that cisplatin negatively affects progenitor cells throughout the CNS: progenitor cells migrating from the subventricular zone to the olfactory bulb, the olfactory epithelium, the dentate gyrus of the hippocampus and the corpus callosum. The subventricular zone, rostral migratory stream and olfactory bulb all showed increases in cell death and decreases in the neuroblast population. This change in progenitor cell numbers remained significant compared to vehicle control for as long as six months. In the olfactory epithelium, we found a significant decrease in proliferation of olfactory receptor neuron (ORN) progenitor cells. There was also a decrease in proliferation and an increase in cell death in the oligodendrocyte precursor cell (OPC) population of the corpus callosum and in the dentate gyrus. Using a fixed interval-60s operant schedule we examined the effects of cisplatin on performance. This schedule allows for the operant response rate to vary widely without altering the rate of reinforcement. When compared to the vehicle control, we found significant changes in response rate. These findings demonstrate that even in the absence of underlying cancer, cisplatin has adverse effects on CNS progenitor cells in multiple regions and negatively impacts behavioral outcomes. This work provides animal models of potential value in developing treatments to prevent the neurotoxic side effects of cisplatin, thus improving quality of life in recipients of this therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2611.
Abstract 2612: Inhibiton of phospholipase C γ 1 enhances senstivity of glioblastoma multiforme to cisplatin and biochanin A
Authors: Jain Aditi , Bhardwaj Vikas , Lai James C. K. , Bhushan Alok
Published: February 2011

Glioblastoma multiforme (GBM), the most prevalent primary brain tumors, is characterized by its invasiveness and poor prognosis of the patients with this disease. Due to its rapid and aggressive nature, it is difficult to treat with conventional therapies. Several new agents have been tested and used for treating glioblastoma but with limited success. Phospholipase C γ 1 (PLC γ 1) is at the point of convergence of many signal transduction pathways and plays an important role in regulating intracellular calcium mobilization and promote cell motility, differentiation and invasion. Inhibition of PLC γ 1 is known to be associated with blocking invasion in gliomas, prostate, breast and bladder carcinomas. In glioblastoma the significance of PLC γ 1 inhibition has been implicated due to its effect on cell motility and invasion. Our laboratory has been investigating the anticancer properties of Biochanin A, a natural isoflavonoid. Biochanin A induces apoptosis, causes cell cycle arrest affecting cellular signaling in several cancers. Previous studies in our laboratory have shown that Biochanin A inhibits invasion in GBM cells. In GBM several signaling pathways are upregulated leading to tumor progression and thus designing targeted therapies is still a major challenge. In this study we investigated the cytotoxic potential of PLC γ 1 inhibitor (U73122) in combination with Biochanin A or with Cisplatin on U87 MG cells (human glioblastoma cell line). We hypothesized that the combinations would enhance the anti-proliferative and anti-invasive properties of the two compounds. We performed a dose response assay using these compounds alone and in combination. At 5µM, U73122 is effective in decreasing cell survival. We also found that U73122 is effective in enhancing the cytotoxic potential of Biochanin A and Cisplatin. Further, we determined the effect of U73122 (5μM) alone and in combination with either of the two compounds on cell signaling, invasive processes and transcription factors. Western blot analysis shows a decrease in the protein expression of p-AKT, NFκ-β, uPAR. Our results implicate that inhibition of PLC γ 1 can augment the cytotoxic potential of Biochanin A and Cisplatin and decrease progression of GBM. These findings have a therapeutic implication in GBM treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2612.
Abstract 2616: Thioredoxin reductase 1 modulates methylseleninic acid-induced redox status effects in A549 human lung cancer cells
Authors: Poerschke Robyn L. , Moos Philip J.
Published: February 2011

Thioredoxin reductase (TR1) is a selenoprotein that is involved in cellular redox status control and deoxyribonucleotide biosynthesis. Many cancers, including lung, overexpress TR1, making it a potential cancer therapy target. TR1 is hypothesized to be involved in the mechanism of selenium in cancer etiology. Also of interest is the selenocompound methylseleninic acid (MSA). MSA is a known substrate of TR1 and previous work has shown that TR1 knockdown enhances MSA toxicity and redox status effects in human colon cancer cells compared to those with endogenous TR1 levels. However, it is unknown if TR1 knockdown produces similar effects of MSA in human lung cancer cells. To further elucidate the role of TR1 in the mechanism of MSA in lung cancer, a lentiviral microRNA delivery system to knockdown TR1 expression in A549 adenocarcinoma cells (A549 miR-TR1) was utilized. Redox status after 24 hr MSA treatment was assessed by measuring reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, and total glutathione (GSH) concentration. Although the toxicity of MSA was not increased in A549 miR-TR1 cells at 24 hrs, changes in redox status parameters were observed. TR1 knockdown alone had no effect on mitochondrial membrane depolarization or ROS, but did increase ROS and mitochondrial membrane depolarization generated by MSA. Total GSH concentration was increased by TR1 knockdown alone, the majority of which was reduced glutathione. MSA decreased total GSH concentration and TR1 knockdown further enhanced this MSA-induced attenuation in total GSH. These results indicate the ability of TR1 to modulate the redox status effects of MSA in human lung cancer cells. Potential use of MSA as a cancer treatment in combination with TR1 inhibitors is also of interest.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2616.
Abstract 262: Upregulation of neutrophil gelatinase-associated lipocalin by ErbB2 through NF-κB activation
Authors: Li Shau-Hsuan , Hawthorne Valerie S. , Neal Christopher L. , Sanghera Sartaj , Xu Jia , Yang Jun , Guo Hua , Steeg Patricia S. , Yu Dihua
Published: February 2011

ErbB2 (HER2, neu) is a receptor tyrosine kinase overexpressed in about 25% of invasive breast carcinomas. Neutrophil gelatinase-associated lipocalin (NGAL) is a secreted glycoprotein expressed in a variety of cancers including breast carcinomas. NGAL can inhibit erythroid cell production leading to anemia. Anemia usually occurs in cancer patients and negatively impacts quality of life. However, current treatment for cancer-related anemia has potential complications. ErbB2, NGAL, and anemia have all been associated with increased metastasis and poor prognosis in breast cancer patients, although the relationship between ErbB2 and NGAL expression is not clear. Here, using breast cancer cell lines in vitro and transgenic mice carrying the activated c-neu oncogene driven by a mouse mammary tumor virus (MMTV-neu) in vivo, we demonstrate that ErbB2 overexpression leads to NGAL upregulation, which is dependent on nuclear factor kappa B (NF-κB) activity. MMTV-neu transgenic mice developed anemia after tumor onset, and anemia progression could be partially arrested by an NF-κB inhibitor and an ErbB2-targeted therapy. Taken together, upregulation of NGAL by ErbB2 through NF-κB activation is involved in cancer-related anemia, and ErbB2, NF-κB, NGAL pathway may serve as potential therapeutic targets for cancer-related anemia.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 262.
Abstract 2621: Telomere length in peripheral blood mononuclear cells (PBMNC) predicts for leukopenia, neutropenia and mucositis in colorectal cancer patients treated with 5FU
Authors: Sakoff Jennette A. , Garg Madhu B. , Adler Kim , Scorgie Fiona E. , Lincz Lisa F. , Ackland Stephen P.
Published: February 2011

Defining the parameters contributing to variability in clinical toxicity is necessary to optimise cancer treatment. Some variability is accounted for by variations in 5FU pharmacokinetics, differences in co-morbidity (liver & renal), pre-disposing factors (gender & age). But a considerable amount remains unexplained. This study aims to identify various factors contributing to such toxicity in colorectal cancer patients receiving 5FU. The variables chosen for study include those that control 5FU metabolism including measures of dihydropyrimidine dehydrogenase (DPD) activity which is critical for 5FU catabolism, together with polymorphic analysis of thymidylate synthase (TS), methyltetrahydrofolate reductase (MTHFR) and methionine synthase (MS) activity. The addition of pharmacodymamics and the ability of end-organs to respond to drug treatment further refined the predictive model, particularly the ability to identify those patients most likely to experience severe myelosuppression in response to chemotherapy. In this regard, the replicative capacity of bone marrow progenitors was determined by measuring telomere length (TL) in peripheral blood mononuclear cells (PBMNC). Clinical toxicity was determined in 42 colorectal patients receiving 5FU. Toxicity (≥ grade 2) included neutropenia (n=25), leukopenia (n=14), mucositis (n=19) and diarrhea (n=5). While the severity of toxicity significantly correlated with the magnitude of the insult, ie 5FU dose, the analysis also showed that toxicity significantly correlated with TL, with short telomeres predicting for higher toxicity. Univariate analysis showed TL significantly correlated with leukopenia (r=-0.461, P=0.009), neutropenia (r=-0.413, P=0.021) and mucositis (r=-0.341, P=0.048). Multivariate analysis further confirmed the significant role of TL in these clinical toxicities. Collectively, these results support the link between TL and progenitor replicative capacity. In conclusion, PBMNC TL may be exploited to tailor chemotherapy schedules for colorectal cancer patients receiving 5FU.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2621.
Abstract 2623: Induction of Bmf and Bim in Vorinostat-induced apoptosis in mantle cell lymphoma
Authors: Xargay-Torrent Silvia , Roue Gael , Lopez-Guerra Monica , Campo Elias , Colomer Dolors
Published: February 2011

OBJECTIVES: Mantle cell lymphoma (MCL) is an incurable B-cell neoplasm harboring the t(11;14)(q13;q32) which leads to the overexpression of cyclin D1, with the consequent cell cycle deregulation. Usually, MCL is characterized by bad prognosis and an aggressive course of the disease. Current therapies have shown limited efficacy. Recently, Histone Deacetylase Inhibitors (HDACis) have been successfully introduced for the treatment of several cancers, including hematological malignancies. Accordingly, tumor suppressor genes are frequently epigenetically silenced in these entities, due to histone deacetylation in their promoters. Therefore, our purposes were to evaluate the antitumoral properties of the HDACi suberoylanilide hydroxamic acid (Vorinostat; Merck & Co) in MCL, and to describe the molecular mechanisms involved in HDACi signaling in this disorder.

METHODS: MCL cell lines and primary MCL cells were used. HDAC activity was measured using a colorimetric HDAC Assay Kit. Flow cytometry was used to determine sensitivity to Vorinostat through measurement of AnnexinV binding, and to analyze apoptosis features. Vorinostat anti-tumoral signaling was evaluated by RQ-PCR determination of gene transcription, western blot analysis and acetyl Histone H4 ChIP assays.

RESULTS: Vorinostat exhibited a heterogeneous cytotoxic effect among MCL cell lines, with a median LD50 of 6.6 μM after 24-hour incubation. Nevertheless, cytotoxicity increased notably after 48h of exposure to the drug with LD50 ranging from 0.4 to 5.3 μM. Interestingly, 7 out of the 10 MCL primary samples tested were extremely sensitive to the compound (with a median LD50 of 2.2 μM after 24-hour incubation). Vorinostat increases the acetylation of H3 and H4 histones, as well as inhibits global HDAC activity in just 1 hour of incubation. The drug notably decreases cyclin D1 protein levels while induces upregulation of the proapoptotic BH3-only proteins Bmf and Bim, triggering the mitochondria-dependent cell death and activation of the caspases cascade. Acetyl Histone H4 ChIP assays showed that Vorinostat increases acetylation of BMF and BIM gene promoters, consequently up regulating Bim and Bmf mRNA levels.

CONCLUSIONS: This study suggests that Vorinostat could define a new and attractive therapeutic approach for the treatment of MCL. We identify BMF and BIM as possible crucial target genes of HDAC inhibitors in MCL cells, promoting the induction of mitochondria-mediated apoptosis.

GRANTS: This work is supported by Ministerio de Ciencia e Innovación SAF 06-8850; S. X-T is a fellow from Ministerio de Ciencia e Innovación (FPU predoctoral fellowship).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2623.
Abstract 2633: Adenosine analog enhances actions of 17-AAG
Authors: Cervantes-Gomez Fabiola , Nimmanapalli Ramadevi , Gandhi Varsha
Published: February 2011

Heat shock protein 90 (HSP90) is a molecular chaperone that regulates the functional stability of client oncoproteins, which is driven by the binding and hydrolysis of ATP. The geldanamycin analog, 17-AAG, binds to the ATP pocket of HSP90 leading to the degradation of client proteins. However, 17-AAG also induces transcription of antiapoptotic HSP70 and HSP27 resulting in cell death resistance. The nucleoside analog 8-Chloro-Adenosine (8-Cl-Ado), currently in clinical trial, is a transcription inhibitor that gets metabolized into its cytotoxic form 8-Cl-ATP causing a parallel decrease of the cellular ATP pool. Based on its mechanisms of action we hypothesize that the combination of 17-AAG and 8-Cl-Ado will result in a favorable effect on cytotoxicity.   % Cell Death   Annexin V / 7-AAD TreatmentsHrsMM.1S8226-RPMIU2661)17-AAG 0.5 µM85452)17-AAG 0.5 µM202463)8-Cl-Ado 10 µM125324)8-Cl-Ado 10 µM2022825)17-AAG→8-Cl-Ado8→12 = 201511106)8-Cl-Ado→17-AAG12→8 = 205515197)8-Cl-Ado+17-AAG20421434

As shown in the Table, simultaneous or sequential combination (rows 6 and 7) were more than additive in multiple myeloma cell lines. With 17-AAG alone, there was a transcriptional induction of HSP90α, HSP90β, HSP70, HSC70 and HSP27 as measured by real time RT-PCR. With the drug combinations, there was no reduction of the 17-AAG-induced HSPs mRNA levels, rather a several fold increase was observed for the stress-inducible HSP70 and HSP27. In accordance, the protein levels of the HSPs were also increased when treated with 17-AAG but remained the same when 8-Cl-Ado was added. This suggests that the transcription inhibition by 8-Cl-Ado was not able to abrogate 17-AAG-mediated HSP induction. The transcript levels for client proteins (STAT3, Akt and c-Raf) remained at endogenous levels when treated with the drugs alone or in combination. However, the combination treatments resulted in a greater decline of the protein expression of STAT3 (1-60%), Akt (42-78%), and Raf-1 (25-85%). This may be due to the reduction in intracellular ATP levels after 8-Cl-Ado treatment, MM.1S (57%), 8226-RPMI (24%), and U266 (56%). Taken together, the increased cytotoxicity of 17-AAG and 8-Cl-Ado combination is mediated by the actions of 8-Cl-Ado on the cellular ATP pool and not due to its effect on transcription.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2633.
Abstract 2636: Preclinical evaluation of the Hsp90 inhibitor KW-2478 in combination with bortezomib as a treatment for multiple myeloma
Authors: Ishii Toshihiko , Nakashima Takayuki , Seike Toshihiro , Shudo Aiko , Akinaga Shiro , Soga Shiro , Shiotsu Yukimasa
Published: February 2011

KW-2478 is a novel Hsp90 inhibitor with a new chemical structure and is under clinical investigation in multiple myeloma patients. Our previous study revealed that KW-2478 bind to N-terminal ATP/ADP pocket and thus inducing apoptosis in myeloma cells. Others have reported that bortezomib, a proteasome inhibitor, induces apoptosis of myeloma cells through increase of ER stress mediator protein such as Noxa. Since Hsp90 inhibition can also causes cellular stress, combining Hsp90 inhibitor and bortezomib may be of therapeutic benefit. In this study, we assessed the combined effect of KW-2478 with bortezomib using human myeloma cell lines. In OPM2/GFP cells, KW-2478 enhanced caspase activation of bortezomib in vitro and this effect was revealed to be mediated through synergistic induction of Noxa. Interestingly KW-2478 reduced bortezomib-induced level of another ER stress mediator, Puma in the same cells. To see if this in vitro effect is translated into in vivo setting, we evaluated combined anti-tumor activity of KW-2478 with bortezomib in s.c. inoculated NCI-H929 human myeloma model. In this model, twice weekly treatment of KW-2478 at the dose of 50 mg/kg (1/4 of MTD) showed synergistic anti-tumor effect with 1 mg/kg bortezomib, without significant body weight loss. Our previous studies showed that KW-2478 showed anti-tumor activity in bone marrow environment, the combined effect of KW-278 with bortezomib was further evaluated using an orthotopic myeloma model in which OPM2/GFP cells were i.v. inoculated. The combination of KW-2478 with bortezomib showed synergistic reduction of myeloma cells in bone marrow and this effect was reflected in a significant decrease in serum M protein level. Our results strongly suggested that combination of KW-2478 with bortezomib may exhibit the enhanced anti-tumor activity against human myeloma than bortezomib alone. Clinical study for combination of KW-2478 with bortzomib in myeloma patients is warranted.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2636.