bluuebunny/crossref_metadata_2025 huggingface dataset:
Targeting the Fanconi Anemia/BRCA Pathway Circumvents Drug Resistance in Multiple Myeloma
Authors: Yarde Danielle N. , Oliveira Vasco , Mathews Linda , Wang Xingyu , Villagra Alejandro , Boulware David , Shain Kenneth H. , Hazlehurst Lori A. , Alsina Melissa , Chen Dung-Tsa , Beg Amer A. , Dalton William S.
Published: November 2009

The Fanconi anemia/BRCA (FA/BRCA) DNA damage repair pathway plays a pivotal role in the cellular response to replicative stress induced by DNA alkylating agents and greatly influences drug response in cancer treatment. We recently reported that FA/BRCA genes are overexpressed and causative for drug resistance in human melphalan-resistant multiple myeloma cell lines. However, the transcriptional regulation of the FA/BRCA pathway is not understood. In this report, we describe for the first time a novel function of the NF-κB subunits, RelB/p50, as transcriptional activators of the FA/BRCA pathway. Specifically, our findings point to constitutive phosphorylation of IκB kinase α and subsequent alterations in FANCD2 expression and function as underlying events leading to melphalan resistance in repeatedly exposed multiple myeloma cells. Inhibiting NF-κB by small interfering RNA, blocking the IκB kinase complex with BMS-345541, or using the proteasome inhibitor bortezomib drastically reduced FA/BRCA gene expression and FANCD2 protein expression in myeloma cells, resulting in diminished DNA damage repair and enhanced melphalan sensitivity. Importantly, we also found that bortezomib decreases FA/BRCA gene expression in multiple myeloma patients. These results show for the first time that NF-κB transcriptionally regulates the FA/BRCA pathway and provide evidence for targeting Fanconi anemia–mediated DNA repair to enhance chemotherapeutic response and circumvent drug resistance in myeloma patients. [Cancer Res 2009;69(24):9367–75]
Confounding Effects in “A Six-Gene Signature Predicting Breast Cancer Lung Metastasis”: Reply
Authors: Driouch Keltouma , Bonin Florian , Sin Soraya , Clairac Géraldine , Lidereau Rosette
Published: November 2009

Molecular signatures have begun to elucidate the biological and molecular mechanisms underlying the phenotypic diversity of breast tumors. Breast tumors are characterized by five different molecular subtypes that are associated with distinct clinical outcomes in terms of prognosis, treatment response, and site of relapse. In particular, the basal-like and luminal B subtypes of tumors are more aggressive and have a higher tendency to metastasize to the lung than do the other subtypes. Given this difference in metastatic profiles of breast tumors, the six-gene signature (6GS) that we showed to be predictive of lung relapse was reexamined in the context of the tumor subtypes. This first analysis suggested that the 6GS is a surrogate for molecular subtype, discriminating basal-like tumors rather than tumors that metastasize to the lung. Here, we show that the 6GS discriminates the two overlapping features, the basal-like subtype and the tendency to metastasize to the lung. Nevertheless, the 6GS predicts lung metastases of breast tumors independent of the molecular subtypes. [Cancer Res 2009;69(24):9507–11]
Construction and Characterization of Novel, Recombinant Immunotoxins Targeting the Her2/neu Oncogene Product: In vitro and In vivo Studies
Authors: Cao Yu , Marks James D. , Marks John W. , Cheung Lawrence H. , Kim Sehoon , Rosenblum Michael G.
Published: November 2009

The goal of this study was to characterize a series of anti-Her2/neu immunotoxin constructs to identify how different antibodies and linker choices affect the specificity and cytotoxicity of these proteins. We constructed a series of immunotoxins containing either the human single-chain antibody (scFv) C6.5 or the murine scFv e23 fused to the highly toxic recombinant gelonin (rGel) molecule. Based on the flexible GGGGS linker (L), the fusion construct C6.5-L-rGel was compared with e23-L-rGel to evaluate the specific cytotoxic effects against Her2/neu-positive and Her2/neu-negative tumor cells. Both constructs retained the specificity of the original antibody as well as the biological activity of rGel toxin. The two constructs displayed similar cytotoxicity against different carcinoma cells. We additionally introduced the modified linkers TRHRQPRGWEQL (Fpe) and AGNRVRRSVG (Fdt), which contained furin cleavage sites, to determine the effect of these design changes on stability and cell killing efficiency. The introduction of furin cleavage linkers (Fpe or Fdt) into the molecules resulted in dissimilar sensitivity to protease cleavage compared with the constructs containing the L linker, but very similar intracellular rGel release, cytotoxic kinetics, and induction of autophagic cell death in vitro. Xenograft studies with SKOV3 ovarian tumors were done using various C6.5/rGel constructs. C6.5-L-rGel was more efficient in tumor inhibition than constructs containing furin linkers, attributing to a higher stability in vivo of the L version. Therefore, our studies suggest that human C6.5-L-rGel may be an effective novel clinical agent for therapy of patients with Her2/neu-overexpressing malignancies. [Cancer Res 2009;69(23):8987–95]
Prevention of Mammary Carcinogenesis in MMTV-neuMice by Cruciferous Vegetable Constituent Benzyl Isothiocyanate
Authors: Warin Renaud , Chambers William H. , Potter Douglas M. , Singh Shivendra V.
Published: November 2009

Benzyl isothiocyanate (BITC), a constituent of edible cruciferous vegetables, inhibits growth of human breast cancer cells in culture. The present study provides in vivo evidence for efficacy of BITC for prevention of mammary cancer in MMTV-neu mice. Administration of BITC at 1 and 3 mmol/kg diet for 25 weeks markedly suppressed the incidence and/or burden of mammary hyperplasia and carcinoma in female MMTV-neu mice without causing weight loss or affecting neu protein level. For example, cumulative incidence of hyperplasia/carcinoma was significantly lower in mice fed BITC-supplemented diets compared with control mice (P = 0.01 by Fisher's test). The BITC-mediated prevention of mammary carcinogenesis correlated with suppression of cell proliferation and increased apoptosis. The average number of Ki-67–positive cells in the carcinoma lesions of 3 mmol BITC group was lower by ∼21% (P < 0.05) compared with tumors from control mice. Apoptotic bodies in the mammary tumor were higher by about 2- to 2.5-fold in the 1 and 3 mmol BITC treatment groups (P < 0.05) compared with control group. The BITC administration also resulted in overexpression of E-cadherin and infiltration of CD3+ T-cells in the tumor. Although BITC treatment increased cytotoxicity of natural killer (NK) cells in vitro, dietary feeding of BITC failed to augment NK cell lytic activity in an ex vivo assay. The present study demonstrating efficacy of BITC against mammary cancer in an animal model provides impetus to determine its activity in a clinical setting. [Cancer Res 2009;69(24):9473–80]
MBP-1 Inhibits Breast Cancer Growth and Metastasis in Immunocompetent Mice
Authors: Kanda Tatsuo , Raychoudhuri Amit , Steele Robert , Sagartz John E. , West Cheri , Ray Ratna B.
Published: November 2009

Breast cancer is the leading cause of cancer death among women. We have shown previously an antiproliferative effect of MBP-1 on several human cancer cells. In this study, we have examined the potential of MBP-1 as a gene therapeutic candidate in regression of breast cancer growth and metastasis in an immunocompetent mouse model. For this, we have used a mouse breast cancer cell line (EO771) and syngeneic C57BL/6 mice. EO771 cells were implanted into the mammary fat pad of C57BL/6 mice. Replication-deficient recombinant adenovirus expressing MBP-1 was administered intratumorally to determine gene therapeutic potential. The results showed a significant regression of primary and distant (lung) tumor growth. Animals exhibited prolonged survival on treatment with MBP-1 compared with the control group (dl312). Subsequent studies suggested that MBP-1 inhibits matrix metalloproteinase expression in human breast cancer cells. Cells transduced with MBP-1 displayed inhibition of migration in a wound-healing assay. The conditioned medium from MBP-1–transduced cells blocked in vitro tube formation assay and inhibited expression of several angiogenic molecules. Taken together, our study shows that MBP-1 acts as a double-edged sword by inhibiting primary and metastatic tumor growth and modulating matrix metalloproteinase expression with a therapeutic potential against breast cancer progression. [Cancer Res 2009;69(24):9354–9]
Srcasm Inhibits Fyn-Induced Cutaneous Carcinogenesis with Modulation of Notch1 and p53
Authors: Zhao Liang , Li Weijie , Marshall Christine , Griffin Thomas , Hanson Matthew , Hick Ryan , Dentchev Tzvete , Williams Erik , Werth Adrienne , Miller Christopher , Bashir Hasan , Pear Warren , Seykora John T.
Published: November 2009

Src family tyrosine kinases (SFK) regulate cell proliferation, and increased SFK activity is common in human carcinomas, including cutaneous squamous cell carcinomas (SCC) and its precursors. The elevated SFK activity in cutaneous SCCs was modeled using K14-Fyn Y528F transgenic mice, which spontaneously form punctate keratotic lesions, scaly plaques, and large tumors resembling actinic keratoses, SCC in situ, and SCCs, respectively. Lesional tissue showed increased levels of activated SFKs, PDK1, STAT3, and ERK1/2, whereas Notch1/NICD protein and transcript levels were decreased. p53 levels also were decreased in SCC in situ and SCCs. Increasing Srcasm levels using a K14-Fyn Y528F/K14-Srcasm double transgenic model markedly inhibited cutaneous neoplasia. In contrast, increased expression of a nonphosphorylatable Srcasm mutant maintained the neoplastic phenotype. Increasing Srcasm levels decreased levels of Fyn, activated SFKs, ERK1/2, PDK1, and phospho-STAT3, and increased Notch1/NICD and p53 levels. Analysis of human specimens revealed that levels of Fyn and activated SFKs were elevated in SCCs compared with adjacent nonlesional epidermis. In addition, Notch1 and Srcasm protein and transcript levels were decreased in human SCCs compared with nonlesional epidermis. Therefore, the SCCs produced by the Fyn Y528F mice resemble their human counterparts at the molecular level. K14-Fyn Y528F mice represent a robust model of cutaneous carcinogenesis that manifests precancerous lesions and SCCs resembling human disease. The Fyn/Srcasm signaling nexus modulates activity of STAT3, PDK1, ERK1/2, Notch1, and p53. Further study of Fyn and Srcasm should provide insights into the mechanisms regulating keratinocyte proliferation and skin carcinogenesis. [Cancer Res 2009;69(24):9439–47]
Genetic Factors on Mouse Chromosome 18 Affecting Susceptibility to Testicular Germ Cell Tumors and Permissiveness to Embryonic Stem Cell Derivation
Authors: Anderson Philip D. , Nelson Vicki R. , Tesar Paul J. , Nadeau Joseph H.
Published: November 2009

Despite strong heritability, little is known about the genetic control of susceptibility to testicular germ cell tumors (TGCT) in humans or mice. Although the mouse model of spontaneous TGCTs has been extensively studied, conventional linkage analysis has failed to locate the factors that control teratocarcinogenesis in the susceptible 129 family of inbred strains. As an alternative approach, we used both chromosome substitution strains (CSS) to identify individual chromosomes that harbor susceptibility genes and a panel of congenic strains derived from a selected CSS to determine the number and location of susceptibility variants on the substituted chromosome. We showed that 129-Chr 18MOLF males are resistant to spontaneous TGCTs and that at least four genetic variants control susceptibility in males with this substituted chromosome. In addition, early embryonic cells from this strain fail to establish embryonic stem cell lines as efficiently as those from the parental 129/Sv strain. For the first time, 129-derived genetic variants that control TGCT susceptibility and fundamental aspects of embryonic stem cell biology have been localized in a genetic context in which the genes can be identified and functionally characterized. [Cancer Res 2009;69(23):9112–7]
Targeting the RET Pathway in Thyroid Cancer
Authors: Wells Samuel A. , Santoro Massimo
Published: November 2009

The RET (rearranged during transfection) protooncogene encodes a single pass transmembrane receptor that is expressed in cells derived from the neural crest and the urogenital tract. As part of a cell-surface complex, RET binds glial derived neurotrophic factor (GDNF) ligands in conjunction with GDNF-family α co-receptors (GFRα). Ligand-induced activation induces dimerization and tyrosine phosphorylation of the RET receptor with downstream activation of several signal transduction pathways. Activating germline RET mutations play a central role in the development of the multiple endocrine neoplasia (MEN) syndromes MEN2A, MEN2B, and familial medullary thyroid carcinoma (FMTC) and also in the development of the congenital abnormality Hirschsprung's disease. Approximately 50% of patients with sporadic MTC have somatic RET mutations, and a significant portion of papillary thyroid carcinomas result from chromosomal inversions or translocations, which activate RET (RET/PTC oncogenes). The RET protooncogene has a significant place in cancer prevention and treatment. Timely thyroidectomy in kindred members who have inherited a mutated RET allele, characteristic of MEN2A, MEN2B, or FMTC, can prevent MTC, the most common cause of death in these syndromes. Also, recently developed molecular therapeutics that target the RET pathway have shown activity in clinical trials of patients with advanced MTC, a disease for which there has been no effective therapy. (Clin Cancer Res 2009;15(23):7119–23)
A Prospective Study of Telomere Length Measured by Monochrome Multiplex Quantitative PCR and Risk of Non-Hodgkin Lymphoma
Authors: Lan Qing , Cawthon Richard , Shen Min , Weinstein Stephanie J. , Virtamo Jarmo , Lim Unhee , Hosgood H. Dean , Albanes Demetrius , Rothman Nathaniel
Published: November 2009

Purpose: Telomere length plays an important role in the maintenance of chromosomal stability and in tumorigenesis. We hypothesized that telomere length in peripheral WBC DNA obtained from healthy individuals would be a predictor of future risk of developing non-Hodgkin lymphoma.

Experimental Design: Using a new assay to measure relative telomere length, monochrome multiplex quantitative PCR, which strongly correlates with telomere length measured by Southern blot (Spearman r = 0.91, P < 0.0001) and has high precision (coefficient of variation = 7%), we compared telomere length in peripheral WBC DNA in 107 incident male non-Hodgkin lymphoma cases and 107 matched controls within the prospective Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort.

Results: Median (10th, 90th percentile) telomere length was 1.10 (0.79, 1.43) in cases and 1.02 (0.78, 1.26) in controls (P = 0.0017, Wilcoxon sign test). There was a strong dose-response relationship between quartiles of telomere length and risk of non-Hodgkin lymphoma overall [odds ratios (95% confidence intervals) by quartile: 1.0; 1.1 (0.4-2.7); 1.8 (0.7-4.9); and 3.6 (1.4-8.9); P trend = 0.003], and this association was similar across the most common non-Hodgkin lymphoma subtypes present in this study.

Conclusion: These results suggest that longer telomere length may be a potential predictor for future risk of non-Hodgkin lymphoma. (Clin Cancer Res 2009;15(23):7429–33)
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

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

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

Purpose: 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

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

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, >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

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

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

Purpose: 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

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

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)
The Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single Oral Doses of CH4987655 in Healthy Volunteers: Target Suppression Using a Biomarker
Authors: Lee Lucy , Niu Huifeng , Rueger Ruediger , Igawa Yuriko , Deutsch Jonathan , Ishii Nobuya , Mu Song , Sakamoto Yuuichiro , Busse-Reid Rachel , Gimmi Claude , Goelzer Petra , De Schepper Stefanie , Yoshimura Yashushi , Barrett Joanne , Ishikawa Yuji , Weissgerber Georges , Peck Richard
Published: November 2009

Purpose: CH4987655 (RO4987655) is an orally active and highly selective small-molecule MEK inhibitor. It potently inhibits mitogen-activated protein kinase signaling pathway activation and tumor cell growth, with an in vitro IC50 of 5.2 nmol/L for inhibition of MEK1/2. Single-agent oral administration of CH4987655 resulted in complete tumor regressions in xenograft models.

Experimental Design: All 40 subjects received a single oral dose followed by 72 hrs of pharmacokinetic, pharmacodynamic, and safety/tolerability assessments. The pharmacodynamics were measured by changes in phosphorylated extracellular signal-regulated kinase (pERK) levels in a surrogate tissue peripheral blood mononuclear cells ex vivo stimulated by PMA.

Results: Doses of 0.5, 1, 2, 3, and 4 mg were safe and well tolerated. No clinically significant safety event was observed. A total of 26 adverse events (n = 15) were reported: 21 mild, 5 moderate, and none severe. Moderate adverse events were experienced by one subject at 1 mg (autonomic nervous system imbalance) and three subjects at 4 mg (diarrhea, abdominal pain, autonomic nervous system and acne). CH4987655 was rapidly absorbed with a tmax of ∼1 h. Exposures were dose proportional from 0.5 to 4 mg. The disposition was biphasic with a terminal t1/2 of ∼25 hr. Intersubject variability was low, 9% to 23% for Cmax and 14% to 25% for area-under-the-curve (AUC). pERK inhibition was exposure dependent and was greater than 80% inhibition at higher doses. The pharmacokinetic-pharmacodynamic relationship was characterized by an inhibitory Emax model (Emax ∼100%; IC50 40.6 ng/mL) using nonlinear mixed-effect modeling.

Conclusions: A significant extent of pERK inhibition was achieved for a single dose that was considered to be safe and well tolerated in healthy volunteers. (Clin Cancer Res 2009;15(23):7368–74)
KIRandHLAGenotypes Are Associated with Disease Progression and Survival following Autologous Hematopoietic Stem Cell Transplantation for High-Risk Neuroblastoma
Authors: Venstrom Jeffrey M. , Zheng Junting , Noor Nabila , Danis Karen E. , Yeh Alice W. , Cheung Irene Y. , Dupont Bo , O'Reilly Richard J. , Cheung Nai-Kong V. , Hsu Katharine C.
Published: November 2009

Purpose: NK cells exhibit cytotoxicity against neuroblastoma. Gene polymorphisms governing NK cell function, therefore, may influence prognosis. Two highly polymorphic genetic loci instrumental in determining NK cell responses encode the NK cell killer immunoglobulin-like receptors (KIR) and their class I human leukocyte antigen (HLA) ligands. We hypothesized that patients with a “missing ligand” KIR-HLA compound genotype may uniquely benefit from autologous hematopoietic stem cell transplantation (HSCT).

Experimental Design: One hundred sixty-nine patients treated with autologous HSCT for stage IV neuroblastoma underwent KIR and HLA genotyping. Patients were segregated according to the presence or absence of HLA ligands for autologous inhibitory KIR. Univariate and multivariate analyses were done for overall and progression-free survival.

Results: Sixty-four percent of patients lacked one or more HLA ligands for inhibitory KIR. Patients lacking a HLA ligand had a 46% lower risk of death [hazard ratio, 0.54; 95% confidence interval (95% CI), 0.35-0.85; P = 0.007] and a 34% lower risk of progression (hazard ratio, 0.66; 95% CI, 0.44-1.0; P = 0.047) at 3 years compared with patients who possessed all ligands for his/her inhibitory KIR. Among all KIR-HLA combinations, 16 patients lacking the HLA-C1 ligand for KIR2DL2/KIR2DL3 experienced the highest 3-year survival rate of 81% (95% CI, 64-100). Survival was more strongly associated with “missing ligand” than with tumor MYCN gene amplification.

Conclusion: KIR-HLA immunogenetics represents a novel prognostic marker for patients undergoing autologous HSCT for high-risk neuroblastoma. (Clin Cancer Res 2009;15(23):7330–4)
Rapid Identification of Clinical Relevant Minor Histocompatibility Antigens via Genome-Wide Zygosity-Genotype Correlation Analysis
Authors: Spaapen Robbert M. , de Kort Ron A.L. , van den Oudenalder Kelly , van Elk Maureen , Bloem Andries C. , Lokhorst Henk M. , Mutis Tuna
Published: November 2009

Purpose: Identification of minor histocompatibility antigens (mHag) with classic methods often requires sophisticated technologies, determination, and patience. We here describe and validate a nonlaborious and convenient genetic approach, based on genome-wide correlations of mHag zygosities with HapMap single-nucleotide polymorphism genotypes, to identify clinical relevant mHags within a reasonable time frame.

Experimental Design: Using this approach, we sought for the mHag recognized by a HLA-DRB1*1501–restricted T-cell clone, isolated from a multiple myeloma patient during a strong graft-versus-tumor effect associated with acute graft-versus-host disease grade 3.

Results: In a period of 3 months, we determined the mHag phenotype of 54 HapMap individuals, deduced the zygosity of 20 individuals, defined the mHag locus by zygosity-genotype correlation analyses, tested the putative mHag peptides from this locus, and finally showed that the mHag is encoded by the arginine (R) allele of a nonsynonymous single-nucleotide polymorphism in the SLC19A1 gene.

Conclusions: We conclude that this powerful and convenient strategy offers a broadly accessible platform toward rapid identification of mHags associated with graft-versus-tumor effect and graft-versus-host disease. (Clin Cancer Res 2009;15(23):7137–43)
E7080, a Multi–Tyrosine Kinase Inhibitor, Suppresses the Progression of Malignant Pleural Mesothelioma with Different Proangiogenic Cytokine Production Profiles
Authors: Ikuta Kenji , Yano Seiji , Trung Van The , Hanibuchi Masaki , Goto Hisatsugu , Li Qi , Wang Wei , Yamada Tadaaki , Ogino Hirokazu , Kakiuchi Soji , Uehara Hisanori , Sekido Yoshitaka , Uenaka Toshimitsu , Nishioka Yasuhiko , Sone Saburo
Published: November 2009

Purpose: Malignant pleural mesothelioma (MPM) is a biologically heterogeneous malignant disease with a poor prognosis. We reported previously that the anti–vascular endothelial growth factor (VEGF) antibody, bevacizumab, effectively inhibited the progression of VEGF-high-producing (but not VEGF-low-producing) MPM cells in orthotopic implantation models, indicating the need for novel therapeutic strategies to improve the poor prognosis of this disease. Therefore, we focused on the multi–tyrosine kinase inhibitor E7080 and assessed its therapeutic efficacy against MPM cells with different proangiogenic cytokine production profiles.

Experimental Design: The efficacy of E7080 was assayed in orthotopic implantation of severe combined immunodeficient mouse models with three human MPM cell lines (MSTO-211H, NCI-H290, and Y-MESO-14).

Results: With regard to proangiogenic cytokine production profiles, MSTO-211H and Y-MESO-14 cells were MPM cells producing high levels of fibroblast growth factor-2 and VEGF, respectively. NCI-H290 cells produced low levels of fibroblast growth factor-2 and VEGF compared with the other two cell lines. E7080 potently suppressed the phosphorylation of VEGF receptor-2 and FGF receptor 1 and, thus, inhibited proliferation of endothelial cells, but not that of the MPM cell lines, in vitro. Orthotopically inoculated MSTO-211H cells produced only thoracic tumors, whereas NCI-H290 and Y-MESO-14 cells also developed pleural effusions. Treatment with E7080 potently inhibited the progression of these three MPM cell lines and markedly prolonged mouse survival, which was associated with decreased numbers of tumor-associated vessels and proliferating MPM cells in the tumor.

Conclusions: These results strongly suggest broad-spectrum activity of E7080 against MPM with different proangiogenic cytokine production profiles in humans. (Clin Cancer Res 2009;15(23):7229–37)
Do We Need a Different Set of Response Assessment Criteria for Tumor Immunotherapy?
Authors: Ribas Antoni , Chmielowski Bartosz , Glaspy John A.
Published: November 2009

Tumor shrinkage induced by tumor immunotherapy may be preceded by inflammatory changes. This confounds the assessment of response rates to tumor immunotherapy. In this issue of Clinical Cancer Research, Wolchok et al. attempt to address this peculiarity by proposing a new set of criteria termed immune-related response criteria. (Clin Cancer Res 2009;15(23):7116–8)