bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions of the Hdm2/p53 and Proteasome Pathways May Enhance the Antitumor Activity of Bortezomib
Authors: Ooi Melissa G. , Hayden Patrick J. , Kotoula Vassiliki , McMillin Douglas W. , Charalambous Elpida , Daskalaki Emily , Raje Noopur S. , Munshi Nikhil C. , Chauhan Dharminder , Hideshima Teru , Buon Leutz , Clynes Martin , O'Gorman Peter , Richardson Paul G. , Mitsiades Constantine S. , Anderson Kenneth C. , Mitsiades Nicholas 
Published: November 2009

Abstract
Purpose: p53 is inactivated in many human malignancies through missense mutations or overexpression of the human homologue of Mdm2 (Hdm2), an E3 ubiquitin ligase that ubiquitinates p53, thereby promoting its proteasomal degradation. The cis-imidazoline nutlin-3 can disrupt the p53-Hdm2 interaction and activate p53, inducing apoptosis in vitro in many malignancies, including multiple myeloma (MM).
Experimental Design: We hypothesized that suppression of Hdm2-mediated p53 ubiquitination may augment sequelae of p53 accumulation caused by proteasomal inhibition. We compared the response of MM cells versus several epithelial cancer models to the proteasome inhibitor bortezomib in combination with nutlin-3.
Results: The combination of sublethal concentrations of bortezomib plus nutlin-3 induced additive cytotoxicity against bortezomib-sensitive MM cell lines. Importantly, however, in breast, prostate, colon, and thyroid (papillary, follicular, anaplastic, and medullary) carcinoma cell lines, this combination triggered synergistic cytotoxicity, and increased expression of p53, p21, Hdm2, Bax, Noxa, PUMA, and cleavage of caspase-3 and poly ADP ribose polymerase. Coculture with bone marrow stromal cells attenuated MM cell sensitivity to nutlin-3 monotherapy and was associated with evidence of suppression of p53 activity in MM cells, whereas combined bortezomib-nutlin-3 treatment maintained cytotoxicity even in the presence of bone marrow stromal cells.
Conclusions: This differential response of MM versus epithelial carcinomas to combination of nutlin-3 with bortezomib sheds new light on the role of p53 in bortezomib-induced apoptosis. Concurrent Hdm2 inhibition with bortezomib may extend the spectrum of bortezomib applications to malignancies with currently limited sensitivity to single-agent bortezomib or, in the future, to MM patients with decreased clinical responsiveness to bortezomib-based therapy. (Clin Cancer Res 2009;15(23):7153–60)
Impaired S-Phase Arrest in Acute Myeloid Leukemia Cells with a FLT3 Internal Tandem Duplication Treated with Clofarabine
Authors: Seedhouse Claire , Grundy Martin , Shang Shili , Ronan John , Pimblett Heather , Russell Nigel , Pallis Monica 
Published: November 2009

Abstract
Purpose: Acute myeloid leukemia cells with an internal tandem duplication mutation of FLT3 (FLT3-ITD) have effective DNA repair mechanisms on exposure to drugs. Despite this, the phenotype is not associated with primary resistant disease. We show defects in the response of mutant FLT3 AML cells to the S-phase drug clofarabine that could account for the apparent contradiction.
Experimental Design: We studied responses of AML cells to clofarabine in vitro.
Results: When treated with a short pulse of clofarabine, FLT3-ITD–harboring MOLM-13 and MV4.11 cells undergo similar damage levels (γH2AX foci) to wild-type cells but have a better repair capability than wild-type cells. However, whereas the wild-type cells undergo rapid S-phase arrest, the S-phase checkpoint fails in mutant cells. Cell cycle arrest in response to DNA damage in S phase is effected via loss of the transcriptional regulator cdc25A. This loss is reduced or absent in clofarabine-treated FLT3 mutant cells. Furthermore, cdc25A message levels are maintained by the FLT3-ITD, such that message is reduced by 87.5% on exposure to FLT3 small interfering RNA. Primary FLT3-ITD samples from untreated patients also display impaired cell cycle arrest and show enhanced sensitivity on prolonged treatment with clofarabine compared with wild-type samples.
Conclusion: There is a reversal of phenotype in mutant FLT3 cells dependent on the length of exposure to clofarabine. Efficient DNA repair may render the cells resistant to a short pulse of the drug, but a failure of cell cycle checkpoint(s) in S phase renders the cells sensitive to prolonged exposure. (Clin Cancer Res 2009;15(23):7291–8)
ABT-888 Confers BroadIn vivoActivity in Combination with Temozolomide in Diverse Tumors
Authors: Palma Joann P. , Wang Yi-Chun , Rodriguez Luis E. , Montgomery Debra , Ellis Paul A. , Bukofzer Gail , Niquette Amanda , Liu Xuesong , Shi Yan , Lasko Loren , Zhu Gui-Dong , Penning Thomas D. , Giranda Vincent L. , Rosenberg Saul H. , Frost David J. , Donawho Cherrie K. 
Published: November 2009

AbstractPurpose: ABT-888, currently in phase 2 trials, is a potent oral poly(ADP-ribose) polymerase inhibitor that enhances the activity of multiple DNA-damaging agents, including temozolomide (TMZ). We investigated ABT-888+TMZ combination therapy in multiple xenograft models representing various human tumors having different responses to TMZ.Experimental Design: ABT-888+TMZ efficacy in xenograft tumors implanted in subcutaneous, orthotopic, and metastatic sites was assessed by tumor burden, expression of poly(ADP-ribose) polymer, and O6-methylguanine methyltransferase (MGMT).Results: Varying levels of ABT-888+TMZ sensitivity were evident across a broad histologic spectrum of models (55-100% tumor growth inhibition) in B-cell lymphoma, small cell lung carcinoma, non–small cell lung carcinoma, pancreatic, ovarian, breast, and prostate xenografts, including numerous regressions. Combination efficacy in otherwise TMZ nonresponsive tumors suggests that TMZ resistance may be overcome by poly(ADP-ribose) polymerase inhibition. Profound ABT-888+TMZ efficacy was seen in experimental metastases models that acquired resistance to TMZ. Moreover, TMZ resistance was overcome in crossover treatments, indicating that combination therapy may overcome acquired TMZ resistance. Neither tumor MGMT, mismatch repair, nor poly(ADP-ribose) polymer correlated with the degree of sensitivity to ABT-888+TMZ.Conclusions: Robust ABT-888+TMZ efficacy is observed across a spectrum of tumor types, including orthotopic and metastatic implantation. As many TMZ nonresponsive tumors proved sensitive to ABT-888+TMZ, this novel combination may broaden the clinical use of TMZ beyond melanoma and glioma. Although TMZ resistance may be influenced by MGMT, neither MGMT nor other mechanisms of TMZ resistance (mismatch repair) precluded sensitivity to ABT-888+TMZ. Underlying mechanisms of TMZ resistance in these models are not completely understood but likely involve mechanisms independent of MGMT.(Clin Cancer Res 2009;15(23):7277–90)
Targeted Inhibition of Mammalian Target of Rapamycin Signaling Inhibits Tumorigenesis of Colorectal Cancer
Authors: Gulhati Pat , Cai Qingsong , Li Jing , Liu Jianyu , Rychahou Piotr G. , Qiu Suimin , Lee Eun Y. , Silva Scott R. , Bowen Kanika A. , Gao Tianyan , Evers B. Mark 
Published: November 2009

Abstract
Purpose: The mammalian target of rapamycin (mTOR) kinase acts downstream of phosphoinositide 3-kinase/Akt to regulate cellular growth, metabolism, and cytoskeleton. Because ∼60% of sporadic colorectal cancers (CRC) exhibit high levels of activated Akt, we determined whether downstream mTOR signaling pathway components are overexpressed and activated in CRCs.
Experimental Design: HCT116, KM20, Caco-2, and SW480 human CRC cells were used to determine the effects of pharmacologic (using rapamycin) or genetic (using RNAi) blockade of mTOR signaling on cell proliferation, apoptosis, cell cycle progression, and subcutaneous growth in vivo.
Results: We show that the mTOR complex proteins mTOR, Raptor, and Rictor are overexpressed in CRC. Treatment with rapamycin significantly decreased proliferation of certain CRC cell lines (rapamycin sensitive), whereas other cell lines were resistant to its effects (rapamycin resistant). Transient siRNA-mediated knockdown of the mTORC2 protein, Rictor, significantly decreased proliferation of both rapamycin-sensitive and rapamycin-resistant CRC cells. Stable shRNA-mediated knockdown of both mTORC1 and mTORC2 decreased proliferation, increased apoptosis, and attenuated cell cycle progression in rapamycin-sensitive CRCs. Moreover, stable knockdown of both mTORC1 and mTORC2 decreased proliferation and attenuated cell cycle progression, whereas only mTORC2 knockdown increased apoptosis in rapamycin-resistant CRCs. Finally, knockdown of both mTORC1 and mTORC2 inhibited growth of rapamycin-sensitive and rapamycin-resistant CRCs in vivo when implanted as tumor xenografts.
Conclusions: Targeted inhibition of the mTORC2 protein, Rictor, leads to growth inhibition and induces apoptosis in both rapamycin-sensitive and rapamycin-resistant CRCs, suggesting that selective targeting of mTORC2 may represent a novel therapeutic strategy for treatment of CRC.(Clin Cancer Res 2009;15(23):7207–16)
Pro–Prostate-Specific Antigen Measurements in Serum and Tissue Are Associated with Treatment Necessity among Men Enrolled in Expectant Management for Prostate Cancer
Authors: Makarov Danil V. , Isharwal Sumit , Sokoll Lori J. , Landis Patricia , Marlow Cameron , Epstein Jonathan I. , Partin Alan W. , Carter H. Ballentine , Veltri Robert W. 
Published: November 2009

Abstract
Purpose: We assessed the association of quantitative clinical and pathologic information, including serum and tissue pro–prostate-specific antigen (proPSA) measurements, with outcomes among men with prostate cancer in an expectant management (active surveillance) program.
Experimental Design: We identified 71 men enrolled in expectant management with frozen serum and tissue available from diagnosis: 39 subsequently developed unfavorable biopsies (Gleason score ≥7, ≥3 cores positive for cancer, &gt;50% of any core involved with cancer), whereas 32 maintained favorable biopsies (median follow-up, 3.93 years). Serum total PSA, free PSA (fPSA), and [−2]proPSA were measured by the Beckman Coulter immunoassay. [−5/−7]proPSA was evaluated in cancer and benign-adjacent areas (BAA) by quantitative immunohistochemistry. Cox proportional hazards and Kaplan-Meier analyses were used to identify significant associations with unfavorable biopsy conversion.
Results: The ratio [−2]proPSA/% fPSA in serum was significantly higher at diagnosis (0.87 ± 0.44 versus 0.65 ± 0.36 pg/mL; P = 0.02) in men developing unfavorable biopsies. [−5/−7]proPSA tissue staining was more intense (4104.09 ± 3033.50 versus 2418.06 ± 1606.04; P = 0.03) and comprised a greater fractional area (11.58 ± 7.08% versus 6.88 ± 5.20%; P = 0.01) in BAA of these men. Serum [−2]proPSA/% fPSA [hazard ratio, 2.53 (1.18-5.41); P = 0.02], BAA [−5/−7]proPSA % area [hazard ratio, 1.06 (1.01-1.12); P = 0.02] and BAA [−5/−7]proPSA stain intensity [hazard ratio, 1.000213 (1.000071-1.000354); P = 0.003] were significantly associated with unfavorable biopsy in Kaplan-Meier and Cox analyses. Serum [−2]proPSA/% fPSA significantly correlated with BAA [−5/−7]proPSA % area (ρ = 0.40; P = 0.002) and BAA [−5/−7]proPSA stain intensity (ρ = 0.33; P = 0.016).
Conclusions: In a prospective cohort of men enrolled into expectant management for prostate cancer, serum and tissue levels of proPSA at diagnosis are associated with need for subsequent treatment. The increase in serum proPSA/% fPSA might be driven by increased proPSA production from “premalignant” cells in the prostate BAA. (Clin Cancer Res 2009;15(23):7316–21)
Mesenchymal Stem Cell Carriers Protect Oncolytic Measles Viruses from Antibody Neutralization in an Orthotopic Ovarian Cancer Therapy Model
Authors: Mader Emily K. , Maeyama Yoshihiro , Lin Yi , Butler Greg W. , Russell Holly M. , Galanis Evanthia , Russell Stephen J. , Dietz Allan B. , Peng Kah-Whye 
Published: November 2009

Abstract
Purpose: Preexisting antiviral antibodies in cancer patients can quickly neutralize oncolytic measles virus (MV) and decrease its antitumor potency. In contrast to “naked” viruses, cell-associated viruses are protected from antibody neutralization. Hence, we hypothesized that measles virotherapy of ovarian cancer in measles-immune mice might be superior if MV-infected mesenchymal stem cell (MSC) carriers are used.
Experimental Design: Antimeasles antibodies titers in ovarian cancer patients were determined. The protection of MV by MSC from antimeasles antibodies, the in vivo biodistribution profiles, and tumor infiltration capability of MSC were determined. Measles-naïve or immune tumor–bearing mice were treated with naked virus or MSC-associated virus and mice survivals were compared.
Results: MSC transferred MV infection to target cells via cell-to-cell heterofusion and induced syncytia formation in the presence of high titers of antimeasles antibody, at levels that completely inactivated naked virus. Athymic mice bearing i.p. human SKOV3ip.1 ovarian tumor xenografts passively immunized with measles-immune human serum were treated with saline, naked MV, or MV-infected MSC. Bioluminescent and fluorescent imaging data indicated that i.p. administered MSC localized to peritoneal tumors, infiltrated into the tumor parenchyma, and transferred virus infection to tumors in measles naïve and passively immunized mice. Survival of the measles-immune mice was significantly enhanced by treatment with MV-infected MSC. In contrast, survivals of passively immunized mice were not prolonged by treatment with naked virus or uninfected MSC.
Conclusions: MSC should be used as carriers of MV for intraperitoneal virotherapy in measles-immune ovarian cancer patients. (Clin Cancer Res 2009;15(23):7246–55)
Novel Oligoamine Analogues Inhibit Lysine-Specific Demethylase 1 and Induce Reexpression of Epigenetically Silenced Genes
Authors: Huang Yi , Stewart Tracy Murray , Wu Yu , Baylin Stephen B. , Marton Laurence J. , Perkins Brandy , Jones Richard J. , Woster Patrick M. , Casero Robert A. 
Published: November 2009

Abstract
Purpose: Abnormal DNA CpG island hypermethylation and transcriptionally repressive histone modifications are associated with the aberrant silencing of tumor suppressor genes. Lysine methylation is a dynamic, enzymatically controlled process. Lysine-specific demethylase 1 (LSD1) has recently been identified as a histone lysine demethylase. LSD1 specifically catalyzes demethylation of mono– and dimethyl–lysine 4 of histone 3 (H3K4), key positive chromatin marks associated with transcriptional activation. We hypothesized that a novel class of oligoamine analogues would effectively inhibit LSD1 and thus cause the reexpression of aberrantly silenced genes.
Experimental Design: Human colorectal cancer cells were treated with the oligoamines and changes in mono- and dimethyl-H3K4 and other chromatin marks were monitored. In addition, treated cells were evaluated for the reexpression of the aberrantly silenced secreted frizzled-related proteins (SFRP) Wnt signaling pathway antagonist genes. Finally, the effects of the LSD1 inhibitors were evaluated in an in vivo xenograft model.
Results: Treatment of HCT116 human colon adenocarcinoma cells in vitro resulted in increased H3K4 methylation and reexpression of silenced SFRP genes. This reexpression is also accompanied by a decrease in H3K9me2 repressive mark. Importantly, cotreatment with low doses of oligoamines and a DNA methyltransferase inhibitor highly induces the reexpression of the aberrantly silenced SFRP2 gene and results in significant inhibition of the growth of established tumors in a human colon tumor model in vivo.
Conclusions: The use of LSD1-inhibiting oligoamine analogues in combination with DNA methyltransferase inhibitors represents a highly promising and novel approach for epigenetic therapy of cancer. (Clin Cancer Res 2009;15(23):7217–28)
A High-Affinity Fully Human Anti–IL-6 mAb, 1339, for the Treatment of Multiple Myeloma
Authors: Fulciniti Mariateresa , Hideshima Teru , Vermot-Desroches Claudine , Pozzi Samantha , Nanjappa Puru , Shen Zhenxin , Patel Nipun , Smith Ernest S. , Wang Wei , Prabhala Rao , Tai Yu-tzu , Tassone Pierfrancesco , Anderson Kenneth C. , Munshi Nikhil C. 
Published: November 2009

AbstractPurpose: We investigated the in vitro and in vivo anti-multiple myeloma activity of monoclonal antibody (mAb) 1339, a high-affinity fully humanized anti-interleukin 6 mAb (immunoglobulin G1), alone and in combination with conventional and novel anti-multiple myeloma agents, as well as its effect on bone turnover.Experimental Design: We examined the growth inhibitory effect of 1339 against multiple myeloma cell lines in the absence and in the presence of bone marrow stromal cells, alone or in combination with dexamethasone, bortezomib, perifosine, and Revlimid. Using the severe combined immunodeficient (SCID)–hu murine model of multiple myeloma, we also examined the effect of 1339 on multiple myeloma cell growth and multiple myeloma bone disease.Results: mAb 1339 significantly inhibited growth of multiple myeloma cell in the presence of bone marrow stromal cell in vitro, associated with inhibition of phosphorylation of signal transducer and activator of transcription 3, extracellular signal-regulated kinase 1/2, and Akt. In addition, mAb 1339 enhanced cytotoxicity induced by dexamethasone, as well as bortezomib, lenalidomide, and perifosine, in a synergistic fashion. Importantly mAb 1339 significantly enhanced growth inhibitory effects of dexamethasone in vivo in SCID-hu mouse model of multiple myeloma. mAb 1339 treatment also resulted in inhibition of osteoclastogenesis in vitro and bone remodeling in SCID-hu model.Conclusions: Our data confirm in vitro and in vivo anti-multiple myeloma activity of, as well as inhibition of bone turnover by, fully humanized mAb 1339, as a single agent and in combination with conventional and novel agents, providing a rationale for its clinical evaluation in multiple myeloma. (Clin Cancer Res 2009;15(23):7144–52)
KRAS Mutation in Stage III Colon Cancer and Clinical Outcome Following Intergroup Trial CALGB 89803
Authors: Ogino Shuji , Meyerhardt Jeffrey A. , Irahara Natsumi , Niedzwiecki Donna , Hollis Donna , Saltz Leonard B. , Mayer Robert J. , Schaefer Paul , Whittom Renaud , Hantel Alexander , Benson Al B. , Goldberg Richard M. , Bertagnolli Monica M. , Fuchs Charles S. ,   for the Cancer and Leukemia Group B, North Central Cancer Treatment Group, Canadian Cancer Society Research Institute, Southwest Oncology Group
Published: November 2009

Abstract
Purpose: Alterations in the RAS and RAF pathway relate to epigenetic and epigenomic aberrations, and are important in colorectal carcinogenesis. KRAS mutation in metastatic colorectal cancer predicts resistance to anti–epidermal growth factor receptor (EGFR)-targeted therapy (cetuximab or panitumumab). It remains uncertain, however, whether KRAS mutation predicts prognosis or clinical outcome of colon cancer patients independent of anti-EGFR therapy.
Methods: We conducted a study of 508 cases identified among 1,264 patients with stage III colon cancer who enrolled in a randomized adjuvant chemotherapy trial (5-fluorouracil, leucovorin with or without irinotecan) in 1999-2001 (CALGB 89803). KRAS mutations were detected in 178 tumors (35%) by pyrosequencing. Kaplan-Meier and Cox proportional hazard models assessed the prognostic significance of KRAS mutation and adjusted for potential confounders including age, sex, tumor location, tumor/node stage, performance status, adjuvant chemotherapy arm, and microsatellite instability status.
Results: Compared with patients with KRAS-wild-type tumors, patients with KRAS-mutated tumors did not experience any difference in disease-free, recurrence-free, or overall survival. The 5-year disease-free, recurrence-free, and overall survival rates (KRAS-mutated versus KRAS-wild-type patients) were 62% versus 63% (log-rank P = 0.89), 64% versus 66% (P = 0.84), and 75% versus 73% (P = 0.56), respectively. The effect of KRAS mutation on patient survival did not significantly differ according to clinical features, chemotherapy arm, or microsatellite instability status, and the effect of adjuvant chemotherapy assignment on outcome did not differ according to KRAS status.
Conclusions: In this large trial of chemotherapy in stage III colon cancer patients, KRAS mutational status was not associated with any significant influence on disease-free or overall survival. (Clin Cancer Res 2009;15(23):7322–9)
Inhibition of Mammalian Target of Rapamycin Is Required for Optimal Antitumor Effect of HER2 Inhibitors against HER2-Overexpressing Cancer Cells
Authors: Miller Todd W. , Forbes James T. , Shah Chirayu , Wyatt Shelby K. , Manning H. Charles , Olivares Maria G. , Sanchez Violeta , Dugger Teresa C. , de Matos Granja Nara , Narasanna Archana , Cook Rebecca S. , Kennedy J. Phillip , Lindsley Craig W. , Arteaga Carlos L. 
Published: November 2009

Abstract
Purpose: A significant fraction of HER2-overexpressing breast cancers exhibit resistance to the HER2 antibody trastuzumab. Hyperactivity of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway confers trastuzumab resistance, and mammalian target of rapamycin (mTOR) is a major downstream effector of PI3K/AKT. Therefore, we examined whether mTOR inhibitors synergize with trastuzumab.
Experimental Design: Immunocompetent mice bearing HER2+ mammary tumors were treated with trastuzumab, the mTOR inhibitor rapamycin, or the combination. Mice were imaged for tumor cell death using an optical Annexin-V probe and with [18F]FDG positron emission tomography. The signaling and growth effects of the mTOR inhibitor RAD001 on HER2+ cells treated with trastuzumab or lapatinib were evaluated.
Results: Treatment of mice with trastuzumab plus rapamycin was more effective than single-agent treatments, inducing complete regression of 26 of 26 tumors. The combination induced tumor cell death (Annexin-V binding) and inhibited FDG uptake. Rapamycin inhibited mTOR and tumor cell proliferation as determined by phosphorylated S6 and Ki-67 immunohistochemistry, respectively. In culture, the combination of RAD001 plus trastuzumab inhibited cell growth more effectively than either drug alone. Trastuzumab partially decreased PI3K but not mTOR activity. Knockdown of TSC2 resulted in HER2-independent activation of mTOR and dampened the response to trastuzumab and lapatinib. Treatment with the HER2 inhibitor lapatinib decreased phosphorylated S6 and growth in TSC2-expressing cells but not in TSC2-knockdown cells.
Conclusions: Inhibition of PI3K and mTOR are required for the growth-inhibitory effect of HER2 antagonists. These findings collectively support the combined use of trastuzumab and mTOR inhibitors for the treatment of HER2+ breast cancer. (Clin Cancer Res 2009;15(23):7266–76)