Michael

Safety and efficacy of first-line bevacizumab with FOLFOX, XELOX, FOLFIRI and fluoropyrimidines in metastatic colorectal cancer: the BEAT study

BACKGROUND Bevacizumab significantly improves survival when added to chemotherapy for metastatic colorectal cancer (mCRC). The Bevacizumab Expanded Access Trial (BEAT) evaluated the safety and efficacy of bevacizumab plus first-line chemotherapy in a general cohort of patients with mCRC. PATIENTS AND METHODS Patients with unresectable mCRC received chemotherapy (physicians choice) plus bevacizumab [5 mg/kg every 2 weeks (5-fluorouracil regimens) or 7.5 mg/kg every 3 weeks (capecitabine regimens)]. The primary end point was safety, including prospective data collection in patients receiving unanticipated surgery during the study. Secondary objectives were progression-free survival (PFS) and overall survival (OS). RESULTS The final analysis comprised 1914 assessable patients (male 58%; median age 59 years). Chemotherapy included 5-fluorouracil/leucovorin (5-FU/LV) + oxaliplatin (29%), irinotecan plus 5-FU/LV (26%), capecitabine plus oxaliplatin (18%) and monotherapy (16%). Serious/grade 3-5 adverse events of interest for bevacizumab included bleeding (3%), gastrointestinal perforation (2%), arterial thromboembolism (1%), hypertension (5.3%), proteinuria (1%) and wound-healing complications (1%). Sixty-day mortality was 3%. Median PFS was 10.8 months [95% confidence interval (CI) 10.4-11.3 months] and median OS reached 22.7 months (95% CI 21.7-23.8 months). CONCLUSIONS The BEAT study shows that the efficacy and safety profile of bevacizumab in routine clinical practice is consistent with results observed in prospective randomised clinical trials and another large observational study in the United States (BRiTE study).

MET Amplification Identifies a Small and Aggressive Subgroup of Esophagogastric Adenocarcinoma With Evidence of Responsiveness to Crizotinib

PURPOSE Amplification of the MET proto-oncogene in gastroesophageal cancer (GEC) may constitute a molecular marker for targeted therapy. We examined a GEC cohort with follow-up and reported the clinical response of four additional patients with MET-amplified tumors to the small molecule inhibitor crizotinib as part of an expanded phase I cohort study. PATIENTS AND METHODS From 2007 to 2009, patients with GEC were genetically screened as a consecutive series of 489 tumors (stages 0, I, and II, 39%; III, 25%; IV, 36%; n = 222 esophageal, including n = 21 squamous carcinomas). MET, EGFR, and HER2 amplification status was assessed by using fluorescence in situ hybridization. RESULTS Ten (2%) of 489 patients screened harbored MET amplification; 23 (4.7%) harbored EGFR amplification; 45 (8.9%) harbored HER2 amplification; and 411 (84%) were wild type for all three genes (ie, negative). MET-amplified tumors were typically high-grade adenocarcinomas that presented at advanced stages (5%; n = 4 of 80). EGFR-amplified tumors showed the highest fraction of squamous cell carcinoma (17%; n = 4 of 23). HER2, MET, and EGFR amplification were, with one exception (MET and EGFR positive), mutually exclusive events. Survival analysis in patients with stages III and IV disease showed substantially shorter median survival in MET/EGFR-amplified groups, with a rank order for all groups by median survival (from most to least aggressive): MET (7.1 months; P < .001) less than EGFR (11.2 months; P = .16) less than HER2 (16.9 months; P = .89) when compared with the negative group (16.2 months). Two of four patients with MET-amplified tumors treated with crizotinib experienced tumor shrinkage (-30% and -16%) and experienced progression after 3.7 and 3.5 months. CONCLUSION MET amplification defines a small and aggressive subset of GEC with indications of transient sensitivity to the targeted MET inhibitor crizotinib (PF-02341066).

Hypoxic enhancement of exosome release by breast cancer cells

BackgroundExosomes are nanovesicles secreted by tumour cells which have roles in paracrine signalling during tumour progression, including tumour-stromal interactions, activation of proliferative pathways and bestowing immunosuppression. Hypoxia is an important feature of solid tumours which promotes tumour progression, angiogenesis and metastasis, potentially through exosome-mediated signalling.MethodsBreast cancer cell lines were cultured under either moderate (1% O2) or severe (0.1% O2) hypoxia. Exosomes were isolated from conditioned media and quantitated by nanoparticle tracking analysis (NTA) and immunoblotting for the exosomal protein CD63 in order to assess the impact of hypoxia on exosome release. Hypoxic exosome fractions were assayed for miR-210 by real-time reverse transcription polymerase chain reaction and normalised to exogenous and endogenous control genes. Statistical significance was determined using the Student T test with a P value of < 0.05 considered significant.ResultsExposure of three different breast cancer cell lines to moderate (1% O2) and severe (0.1% O2) hypoxia resulted in significant increases in the number of exosomes present in the conditioned media as determined by NTA and CD63 immunoblotting. Activation of hypoxic signalling by dimethyloxalylglycine, a hypoxia-inducible factor (HIF) hydroxylase inhibitor, resulted in significant increase in exosome release. Transfection of cells with HIF-1α siRNA prior to hypoxic exposure prevented the enhancement of exosome release by hypoxia. The hypoxically regulated miR-210 was identified to be present at elevated levels in hypoxic exosome fractions.ConclusionsThese data provide evidence that hypoxia promotes the release of exosomes by breast cancer cells, and that this hypoxic response may be mediated by HIF-1α. Given an emerging role for tumour cell-derived exosomes in tumour progression, this has significant implications for understanding the hypoxic tumour phenotype, whereby hypoxic cancer cells may release more exosomes into their microenvironment to promote their own survival and invasion.

Expression and Prognostic Significance of Metalloproteinases and Their Tissue Inhibitors in Patients With Small-Cell Lung Cancer

PURPOSE Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are important in tumor development and progression. MMP expression has been correlated with advanced clinical stage and poor survival in some tumors, but data for small-cell lung cancer (SCLC) are lacking. The aim of this study was to assess the expression of MMPs and TIMPs in SCLC and to evaluate their importance relative to standard prognostic factors. PATIENTS AND METHODS Expression of MMP-1, -2, -3, -9, -11, -13, and -14 and TIMP-1, -2, -3, and -4 was evaluated by immunohistochemistry (IHC). In situ hybridization was used to confirm expression of specific mRNAs. Clinical data collected included sex, tumor stage, performance status, weight loss, hematology (hemoglobin, WBC, platelets) and biochemistry (sodium, albumin, alkaline phosphatase, lactate dehydrogenase), treatment, and survival. RESULTS Samples from 46 patients were evaluated: 30 males, 16 females; 29 limited, 17 extensive stage; 35 Eastern Cooperative Oncology Group performance status 0-1. Positive IHC staining was evident for MMP-1 and -9 in 60% to 70% of tumor cells, and for MMP-11, -13, and -14 and TIMP-2 and -3 in 70% to 100% of tumor cells. Stromal staining of TIMP-1 to -3 was present in less than 30% of specimens. On multivariate analysis, only stage and decreased tumoral expression of TIMP-1 were significant for response (P =.043). Significant factors for survival were tumor stage (P =.0021); weight loss (P =. 013); and high tumor cell expression of MMP-3 (P =.077), MMP-11 (P =. 031), and MMP-14 (P =.019). MMP and TIMP expression did not differ significantly between stages. CONCLUSION MMPs and TIMPs are widely expressed in SCLC. Increased tumoral expression of MMP-3, -11, and -14 were independent negative prognostic factors for survival. The results support the evaluation of synthetic MMP inhibitors in patients with SCLC.

The VHL-dependent regulation of microRNAs in renal cancer.

BackgroundThe commonest histological type of renal cancer, clear cell renal cell carcinoma (cc RCC), is associated with genetic and epigenetic changes in the von Hippel-Lindau (VHL) tumour suppressor. VHL inactivation leads to induction of hypoxia-inducible factors (HIFs) and a hypoxic pattern of gene expression. Differential levels of specific microRNAs (miRNAs) are observed in several tumours when compared to normal tissue. Given the central role of VHL in renal cancer formation, we examined the VHL-dependent regulation of miRNAs in renal cancer.MethodsVHL-dependent miRNA expression in cc RCC was determined by microarray analysis of renal cell line RCC4 with mutated VHL (RCC4-VHL) and reintroduced wild-type VHL (RCC4 + VHL). Five miRNAs highly upregulated in RCC4 + VHL and five miRNAs highly downregulated in RCC4 + VHL were studied further, in addition to miR-210, which is regulated by the HIF-VHL system. miRNA expression was also measured in 31 cc RCC tumours compared to adjacent normal tissue.ResultsA significant increase in miR-210, miR-155 and miR-21 expression was observed in the tumour tissue. miR-210 levels also showed a correlation with a HIF-regulated mRNA, carbonic anhydrase IX (CAIX), and with VHL mutation or promoter methylation. An inverse correlation was observed between miR-210 expression and patient survival, and a putative target of miR-210, iron-sulfur cluster assembly protein (ISCU1/2), shows reciprocal levels of mRNA expression in the tumours.ConclusionsWe have identified VHL-regulated miRNAs and found that for some the regulation is HIF-dependent and for others it is HIF-independent. This pattern of regulation was also seen in renal cancer tissue for several of these miRNAs (miR-210, miR-155, let-7i and members of the miR-17-92 cluster) when compared with normal tissue. miR-210 showed marked increases in expression in renal cancer and levels correlated with patient survival. The inverse correlation between miR-210 levels and ISCU1/2 provides support for the hypothesis that ISCU1/2 is a target of miR-210 and that it may contribute to the anaerobic respiration seen in renal (and other) tumours.See Commentary: http://www.biomedcentral.com/1741-7015/8/65

Adjuvant Therapy in Gastric Cancer

Gastric cancer has a poor prognosis. The majority of patients will relapse after definitive surgery, and 5-year survival after surgery remains poor. The role of adjuvant therapy in gastric cancer has been controversial given the lack of significant survival benefit in many randomized studies so far. The results of a large North American study (Gastrointestinal Cancer Intergroup Trial INT 0116) reported that postoperative chemoradiotherapy conferred a survival advantage compared with surgery alone, which has led to the regimen being adopted as a new standard of care. However, controversies still remain regarding surgical technique, the place of more effective and less toxic chemotherapy regimens, and the use of more modern radiation planning techniques to improve treatment delivery and outcome in the adjuvant and neoadjuvant setting. This article reviews the current status of the adjuvant treatment for gastric cancer including discussion on the research directions aimed at optimizing treatment efficacy. Issues such as the identification of patients who are more likely to benefit from adjuvant therapy are also addressed. Further clinical trials are needed to move towards better consensus and standardization of care.

Circulating microRNA expression is reduced in chronic kidney disease

BACKGROUND MicroRNAs (miRNAs) are important regulators of gene expression, which have roles in renal development and disease. They exist in biological fluids including blood and urine and may have signalling roles and potential as disease biomarkers. METHODS We measured the levels of miRNAs in patients with different stages of chronic kidney failure including those receiving maintenance haemodialysis treatment. RESULTS In patients with severe chronic renal failure, circulating levels of total and specific miRNAs are reduced in comparison to patients with mild renal impairment or normal renal function. A strong correlation exists between detected circulating miRNAs and estimated glomerular filtration rate, and less strong correlations with other features of chronic kidney disease, such as anaemia and hyperparathyroidism. CONCLUSION These findings have important implications for the use of circulating miRNAs as biomarkers in individuals with renal impairment and for the pathogenesis of uraemia.

MicroRNA profiling of Barrett's oesophagus and oesophageal adenocarcinoma

The genetic changes that drive metaplastic progression from squamous oesophageal mucosa toward intestinal metaplasia and adenocarcinoma are unclear. The aberrant expression of microRNAs (miRNAs) is involved in the development of cancer. This study examined whether miRNAs play a role in the development of oesophageal adenocarcinoma.

Review: The role of microRNAs in kidney disease.

MicroRNAs (miRNAs) are short non‐coding RNAs that modulate physiological and pathological processes by inhibiting target gene expression via blockade of protein translation or by inducing mRNA degradation. These miRNAs potentially regulate the expression of thousands of proteins. As a result, miRNAs have emerged rapidly as a major new area of biomedical research with relevance to kidney disease. MiRNA expression has been shown to differ between the kidney and other organs as well as between different kidney regions. Furthermore, miRNAs have been found to be functionally important in models of podocyte development, diabetic nephropathy and polycystic kidney disease. Of particular interest, podocyte‐specific deletion of Dicer, a key enzyme in the biogenesis of miRNA, results in proteinuria and severe renal impairment in mice. One miRNA (miR‐192) can also act as an effector of transforming growth factor‐β activity in the high‐glucose environment of diabetic nephropathy. Differential expression of miRNAs has been reported in kidney allograft rejection. It is anticipated that future studies involving miRNAs will generate new insights into the complex pathophysiology underlying various kidney diseases, generate diagnostic biomarkers and might be of value as therapeutic targets for progressive kidney diseases. The purpose of this review is to highlight key miRNA developments in kidney diseases and how this might influence the diagnosis and management of patients with kidney disease in the future.

Tumoral Drug Metabolism: Overview and Its Implications for Cancer Therapy

Drug-metabolizing enzymes (DME) in tumors are capable of biotransforming a variety of xenobiotics, including antineoplastics, resulting in either their activation or detoxification. Many studies have reported the presence of DME in tumors; however, heterogeneous detection methodology and patient cohorts have not generated consistent, firm data. Nevertheless, various gene therapy approaches and oral prodrugs have been devised, taking advantage of tumoral DME. With the need to target and individualize anticancer therapies, tumoral processes such as drug metabolism must be considered as both a potential mechanism of resistance to therapy and a potential means of achieving optimal therapy. This review discusses cytotoxic drug metabolism by tumors, through addressing the classes of the individual DME, their relevant substrates, and their distribution in specific malignancies. The limitations of preclinical models relative to the clinical setting and lack of data on the changes of DME with disease progression and host response will be discussed. The therapeutic implications of tumoral drug metabolism will be addressed-in particular, the role of DME in predicting therapeutic response, the activation of prodrugs, and the potential for modulation of their activity for gain are considered, with relevant clinical examples. The contribution of tumoral drug metabolism to cancer therapy can only be truly ascertained through large-scale prospective studies and supported by new technologies for tumor sampling and genetic analysis such as microarrays. Only then can efforts be concentrated in the design of better prodrugs or combination therapy to improve drug efficacy and individualize therapy.