Citations

PurposeBiliary cancers overexpress epidermal growth factor receptor (EGFR), and angiogenesis has been correlated with poor outcome. Erlotinib, an EGFR tyrosine kinase inhibitor, and bevacizumab, a vascular endothelial growth factor (VEGF) inhibitor have each been shown to have activity in biliary cancer. The primary objective of this study was to evaluate the response rate by Response Evaluation Criteria in Solid Tumors (RECIST). Secondary end points included overall survival (OS), time to progression (TTP), VEGF levels, and molecular studies of EGFR and k-ras.Patients and MethodsEligible patients had advanced cholangiocarcinoma or gallbladder cancer. Patients were treated with bevacizumab 5 mg/kg intravenously on days 1 and 15 and erlotinib 150 mg by mouth daily on days 1 through 28. Responses were evaluated by RECIST. VEGF levels were collected, and samples were analyzed for EGFR mutation by polymerase chain reaction.ResultsFifty-three eligible patients were enrolled at eight sites. Of 49 evaluable patients, six (12%; 95% CI, 6% to 27%) had a confirmed partial response. Stable disease was documented in another 25 patients (51%). Rash was the most common grade 3 toxicity. Four patients had grade 4 toxicities. Median OS was 9.9 months, and TTP was 4.4 months. Low repeats (< 16) in EGFR intron 1 polymorphism and G>G k-ras Q38 genotype (wild type) were associated with improved outcomes.ConclusionCombination chemotherapy with bevacizumab and erlotinib showed clinical activity with infrequent grade 3 and 4 adverse effects in patients with advanced biliary cancers. On the basis of preliminary molecular analysis, presence of a k-ras mutation may alter erlotinib efficacy. The combination of bevacizumab and erlotinib may be a therapeutic alternative in patients with advanced biliary cancer.

Abstract The low efficiency of reprogramming and genomic integration of virus vectors obscure the potential application of induced pluripotent stem (iPS) cells; therefore, identification of chemicals and cooperative factors that may improve the generation of iPS cells will be of great value. Moreover, the cellular mechanisms that limit the reprogramming efficiency need to be investigated. Through screening a chemical library, we found that two chemicals reported to upregulate E-cadherin considerably increase the reprogramming efficiency. Further study of the process indicated that E-cadherin is upregulated during reprogramming and the established iPS cells possess E-cadherin-mediated cell–cell contact, morphologically indistinguishable from embryonic stem (ES) cells. Our experiments also demonstrate that overexpression of E-cadherin significantly enhances reprogramming efficiency, whereas knockdown of endogenous E-cadherin reduces the efficiency. Consistently, abrogation of cell–cell contact by the inhibitory peptide or the neutralizing antibody against the extracellular domain of E-cadherin compromises iPS cell generation. Further mechanistic study reveals that adhesive binding activity of E-cadherin is required. Our results highlight the critical role of E-cadherin-mediated cell–cell contact in reprogramming and suggest new routes for more efficient iPS cell generation.

We executed a genome-wide association scan for age-related macular degeneration (AMD) in 2,157 cases and 1,150 controls. Our results validate AMD susceptibility loci near CFH ( P < 10 −75 ), ARMS2 ( P < 10 −59 ), C2/CFB ( P < 10 −20 ), C3 ( P < 10 −9 ), and CFI ( P < 10 −6 ). We compared our top findings with the Tufts/Massachusetts General Hospital genome-wide association study of advanced AMD (821 cases, 1,709 controls) and genotyped 30 promising markers in additional individuals (up to 7,749 cases and 4,625 controls). With these data, we identified a susceptibility locus near TIMP3 (overall P = 1.1 × 10 −11 ), a metalloproteinase involved in degradation of the extracellular matrix and previously implicated in early-onset maculopathy. In addition, our data revealed strong association signals with alleles at two loci ( LIPC , P = 1.3 × 10 −7 ; CETP , P = 7.4 × 10 −7 ) that were previously associated with high-density lipoprotein cholesterol (HDL-c) levels in blood. Consistent with the hypothesis that HDL metabolism is associated with AMD pathogenesis, we also observed association with AMD of HDL-c—associated alleles near LPL ( P = 3.0 × 10 −3 ) and ABCA1 ( P = 5.6 × 10 −4 ). Multilocus analysis including all susceptibility loci showed that 329 of 331 individuals (99%) with the highest-risk genotypes were cases, and 85% of these had advanced AMD. Our studies extend the catalog of AMD associated loci, help identify individuals at high risk of disease, and provide clues about underlying cellular pathways that should eventually lead to new therapies.

Abstract Epidermal growth factor receptor (EGFR) vIII is a mutated EGFR that is frequently overexpressed in glioblastomas and implicated in response to receptor tyrosine kinase inhibitors. In this study, we investigate the effect of ZD6474 (ZACTIMA, vandetanib), a dual inhibitor for vascular endothelial growth factor receptor 2 and EGFR on growth and angiogenesis of gliomas expressing EGFRvIII. We used two glioma xenograft models, U87MG cells overexpressing EGFRvIII and short-term cultured primary glioma GBM8 cells with EGFRvIII. ZD6474 inhibited tumor growth and angiogenesis and induced cell apoptosis in various brain gliomas. Moreover, significant inhibition of EGFRvIII-expressing U87MG and GBM8 gliomas was observed compared with their controls. Magnetic resonance imaging analysis using the apparent diffusion coefficient and three-dimensional T2*weighed measurements validated ZD6474 inhibition on tumor growth and angiogenesis in EGFRvIII-expressing GBM8 gliomas. Mechanistically, ZD6474 shows better inhibition of cell growth and survival of U87MG/EGFRvIII, GBM6, and GBM8 cells that express EGFRvIII than U87MG or GBM14 cells that have nondetectable EGFRvIII through attenuation of activated phosphorylation of signal transducer and activator of transcription 3, Akt, and Bcl-XL expression. Albeit in lesser extent, ZD6474 also displays suppressions of U87MG/EGFR and GBM12 cells that overexpress wild-type EGFR. Additionally, ZD6474 inhibits activation of extracellular signal-regulated kinase 1/2 in both types of cells, and expression of a constitutively active phosphoinositide 3-kinases partially rescued ZD6474 inhibition in U87MG/EGFRvIII cells. Taken together, these data show that ZD6474 significantly inhibited growth and angiogenesis of gliomas expressing EGFRvIII by specifically blocking EGFRvIII-activated signaling mediators, suggesting a potential application of ZD6474 in treatments for glioblastomas that overexpress EGFRvIII. Mol Cancer Ther; 9(4); 929–41. ©2010 AACR.

Abstract Microvesicles (MVs) released by malignant cancer cells constitute an important part of the tumor microenvironment. They can transfer various messages to target cells and may be critical to disease progression. Here, we demonstrate that MVs circulating in plasma of B-cell chronic lymphocytic leukemia (CLL) patients exhibit a phenotypic shift from predominantly platelet derived in early stage to leukemic B-cell derived at advanced stage. Furthermore, the total MV level in CLL was significantly greater compared with healthy subjects. To understand the functional implication, we examined whether MVs can interact and modulate CLL bone marrow stromal cells (BMSCs) known to provide a “homing and nurturing” environment for CLL B cells. We found that CLL-MV can activate the AKT/mammalian target of rapamycin/p70S6K/hypoxia-inducible factor-1α axis in CLL-BMSCs with production of vascular endothelial growth factor, a survival factor for CLL B cells. Moreover, MV-mediated AKT activation led to modulation of the β-catenin pathway and increased expression of cyclin D1 and c-myc in BMSCs. We found MV delivered phospho-receptor tyrosine kinase Axl directly to the BMSCs in association with AKT activation. This study demonstrates the existence of separate MV phenotypes during leukemic disease progression and underscores the important role of MVs in activation of the tumor microenvironment.

Abstract Marrow stromal cells (MSCs) provide important survival and drug resistance signals to chronic lymphocytic leukemia (CLL) cells, but current models to analyze CLL–MSC interactions are heterogeneous. Therefore, we tested different human and murine MSC lines and primary human MSCs for their ability to protect CLL cells from spontaneous and drug-induced apoptosis. Our results show that both human and murine MSCs are equally effective in protecting CLL cells from fludarabine-induced apoptosis. This protective effect was sustained over a wide range of CLL–MSC ratios (5:1 to 100:1), and the levels of protection were reproducible in 4 different laboratories. Human and murine MSCs also protected CLL cells from dexamethasone- and cyclophosphamide-induced apoptosis. This protection required cell–cell contact and was virtually absent when CLL cells were separated from the MSCs by micropore filters. Furthermore, MSCs maintained Mcl-1 and protected CLL cells from spontaneous and fludarabine-induced Mcl-1 and PARP cleavage. Collectively, these studies define common denominators for CLL cocultures with MSCs. They also provide a reliable, validated tool for future investigations into the mechanism of MSC–CLL cross talk and for drug testing in a more relevant fashion than the commonly used suspension cultures.

Abstract Purpose: Esophageal adenocarcinoma is a highly aggressive malignancy that frequently develops from Barrett's esophagus, a premalignant pathologic change occurring in the lower end of the esophagus. Identifying Barrett's esophagus patients at high risk of malignant transformation is essential to the prevention of esophageal adenocarcinoma. Although microRNA (miRNA) expression signatures have been associated with the etiology and prognosis of several types of cancers, their roles in the development of esophageal adenocarcinoma have not been extensively evaluated. Experimental Design: In this study, we analyzed the expression patterns of 470 human miRNAs using Agilent miRNA microarray in 32 disease/normal-paired tissues from 16 patients diagnosed with Barrett's esophagus of either low- or high-grade dysplasia, or esophageal adenocarcinoma. Results: Using unsupervised hierarchical clustering and class comparison analyses, we found that miRNA expression profiles in tissues of Barrett's esophagus with high-grade dysplasia were significantly different from their corresponding normal tissues. Similar findings were observed for esophageal adenocarcinoma, but not for Barrett's esophagus with low-grade dysplasia. The expression patterns of selected miRNAs were further validated using quantitative reverse transcription real-time PCR in an independent set of 75 pairs of disease/normal tissues. Finally, we identified several miRNAs that were involved in the progressions from low grade-dysplasia Barrett's esophagus to esophageal adenocarcinoma. Conclusions: We showed that miRNAs were involved in the development and progression of esophageal adenocarcinoma. The identified significant miRNAs that may become potential targets for early detection, chemoprevention, and treatment of esophageal cancer. (Clin Cancer Res 2009;15(18):5744–52)

Abstract Background. The Bevacizumab Regimens’ Investigation of Treatment Effects (BRiTE) study is a prospective, observational cohort study designed to elucidate safety and effectiveness outcomes associated with bevacizumab combined with chemotherapy as used in clinical practice for first-line treatment of metastatic colorectal cancer (mCRC). Patients and Methods. Baseline characteristics, prespecified bevacizumab-related adverse events, and effectiveness data were collected from 1,953 mCRC patients who were receiving first-line treatment including bevacizumab at 248 U.S. sites. Results. At database lock, the median follow-up was 20.1 months. At baseline, 46% of patients were aged ≥65 years and 49% had an Eastern Cooperative Oncology Group performance status score ≥1. Fluorouracil, leucovorin, and oxaliplatin was the most common first-line chemotherapy regimen (56%). Overall rates of bevacizumab-related adverse events in the BRiTE study, such as gastrointestinal perforation (1.9%), arterial thromboembolic events (2%), grade 3–4 bleeding (2.2%), and de novo hypertension requiring medication (22%), were consistent with those reported in randomized clinical trials (RCTs) of bevacizumab in first-line mCRC treatment. The median progression-free survival (PFS) and overall survival (OS) times were 9.9 (95% confidence interval [CI], 9.5–10.3) months and 22.9 (95% CI, 21.9–24.4) months, respectively. Conclusion. The median PFS and OS durations and safety profile of bevacizumab in the BRiTE study were similar to those in RCTs of bevacizumab plus chemotherapy in first-line mCRC patients. The observations from the BRiTE study complement and expand upon RCT data, providing clinical information in a large cohort of bevacizumab-treated patients and subgroups such as the elderly.

Unilateral renal artery stenosis (RAS) leads to atrophy of the stenotic kidney and compensatory enlargement of the contralateral kidney. Although the two-kidney, one-clip (2K1C) model has been extensively used to model human RAS, the cellular responses in the stenotic and contralateral kidneys, particularly in the murine model, have received relatively little attention. We studied mice 2, 5, and 11 wk after unilateral RAS. These mice became hypertensive within 1 wk. The contralateral kidney increased in size within 2 wk after surgery. This enlargement was associated with a transient increase in expression of phospho-extracellular signal-regulated kinase (p-ERK), the proliferation markers proliferating cell nuclear antigen and Ki-67, the cell cycle inhibitors p21 and p27, and transforming growth factor-β, with return to baseline levels by 11 wk. The size of the stenotic kidney was unchanged at 2 wk but progressively decreased between 5 and 11 wk. Unlike the contralateral kidney, which showed minimal histopathological alterations, the stenotic kidney developed progressive interstitial fibrosis, tubular atrophy, and interstitial inflammation. Surprisingly, the stenotic kidney showed a proliferative response, which involved largely tubular epithelial cells. The atrophic kidney had little evidence of apoptosis, despite persistent upregulation of p53; expression of cell cycle regulatory proteins in the stenotic kidney was persistently increased through 11 wk. These studies indicate that in the 2K1C model, the stenotic kidney and contralateral, enlarged kidney exhibit a distinct temporal expression of proteins involved in cell growth, cell survival, apoptosis, inflammation, and fibrosis. Notably, an unexpected proliferative response occurs in the stenotic kidney that undergoes atrophy.

Lenalidomide is the first karyotype-selective therapeutic approved for the treatment of myelodysplastic syndromes (MDS) owing to high rates of erythroid and cytogenetic response in patients with chromosome 5q deletion [del(5q)]. Although haploinsufficiency for the RPS14 gene and others encoded within the common deleted region (CDR) have been implicated in the pathogenesis of the del(5q) phenotype, the molecular basis of the karyotype specificity of lenalidomide remains unexplained. We focused our analysis on possible haplodeficient enzymatic targets encoded within the CDR that play key roles in cell-cycle regulation. We show that the dual specificity phosphatases, Cdc25C and PP2Acα, which are coregulators of the G 2 -M checkpoint, are inhibited by lenalidomide. Gene expression was lower in MDS and acute myeloid leukemia (AML) specimens with del(5q) compared with those with alternate karyotypes. Lenalidomide inhibited phosphatase activity either directly (Cdc25C) or indirectly (PP2A) with corresponding retention of inhibitory phospho-tyrosine residues. Treatment of del(5q) AML cells with lenalidomide induced G 2 arrest and apoptosis, whereas there was no effect in nondel(5q) AML cells. Small interfering RNA (shRNA) suppression of Cdc25C and PP2Ac α gene expression recapitulated del(5q) susceptibility to lenalidomide with induction of G 2 arrest and apoptosis in both U937 and primary nondel(5q) MDS cells. These data establish a role for allelic haplodeficiency of the lenalidomide inhibitable Cdc25C and PP2Acα phosphatases in the selective drug sensitivity of del(5q) MDS.