Identification of DNA hypermethylation of SOX9 in association with bladder cancer progression using CpG microarrays

CpG island arrays represent a high-throughput epigenomic discovery platform to identify global disease-specific promoter hypermethylation candidates along bladder cancer progression. DNA obtained from 10 pairs of invasive bladder tumours were profiled vs their respective normal urothelium using differential methylation hybridisation on custom-made CpG arrays (n=12 288 clones). Promoter hypermethylation of 84 clones was simultaneously shown in at least 70% of the tumours. SOX9 was selected for further validation by bisulphite genomic sequencing and methylation-specific polymerase chain reaction in bladder cancer cells (n=11) and primary bladder tumours (n=101). Hypermethylation was observed in bladder cancer cells and associated with lack of gene expression, being restored in vitro by a demethylating agent. In primary bladder tumours, SOX9 hypermethylation was present in 56.4% of the cases. Moreover, SOX9 hypermethylation was significantly associated with tumour grade and overall survival. Thus, this high-throughput epigenomic strategy has served to identify novel hypermethylated candidates in bladder cancer. In vitro analyses supported the role of methylation in silencing SOX9 gene. The association of SOX9 hypermethylation with tumour progression and clinical outcome suggests its relevant clinical implications at stratifying patients affected with bladder cancer

p16INK4a hypermethylation and p53, p16 and MDM2 protein expression in Esophageal Squamous Cell Carcinoma

<p>Abstract</p> <p>Background</p> <p>Tumor suppressor genes <it>p53 </it>and <it>p16</it>^INK4aand the proto-oncogene <it>MDM2 </it>are considered to be essential G1 cell cycle regulatory genes whose loss of function is associated with ESCC carcinogenesis. We assessed the aberrant methylation of the <it>p16 </it>gene and its impact on <it>p16</it>^{<it>INK4a </it>}protein expression and correlations with <it>p53 </it>and <it>MDM2 </it>protein expressions in patients with ESCC in the Golestan province of northeastern Iran in which ESCC has the highest incidence of cancer, well above the world average.</p> <p>Methods</p> <p>Cancerous tissues and the adjacent normal tissue obtained from 50 ESCC patients were assessed with Methylation-Specific-PCR to examine the methylation status of <it>p16</it>. The expression of <it>p16</it>, <it>p53 </it>and <it>MDM2 </it>proteins was detected by immunohistochemical staining.</p> <p>Results</p> <p>Abnormal expression of <it>p16 </it>and <it>p53</it>, but not <it>MDM2</it>, was significantly higher in the tumoral tissue. <it>p53 </it>was concomitantly accumulated in ESCC tumor along with <it>MDM2 </it>overexpression and <it>p16 </it>negative expression. Aberrant methylation of the <it>p16</it>^{<it>INK4a </it>}gene was detected in 31/50 (62%) of esophageal tumor samples, while two of the adjacent normal mucosa were methylated (P < 0.001). <it>p16</it>^{<it>INK4a </it>}aberrant methylation was significantly associated with decreased <it>p16 </it>protein expression (P = 0.033), as well as the overexpression of <it>p53 </it>(P = 0.020).</p> <p>Conclusions</p> <p><it>p16 </it>hypermethylation is the principal mechanism of <it>p16 </it>protein underexpression and plays an important role in ESCC development. It is associated with p53 protein overexpression and may influence the accumulation of abnormally expressed proteins in <it>p53-MDM2 </it>and <it>p16-Rb </it>pathways, suggesting a possible cross-talk of the involved pathways in ESCC development.</p

Forest biodiversity, ecosystem functioning and the provision of ecosystem services

Forests are critical habitats for biodiversity and they are also essential for the provision of a wide range of ecosystem services that are important to human well-being. There is increasing evidence that biodiversity contributes to forest ecosystem functioning and the provision of ecosystem services. Here we provide a review of forest ecosystem services including biomass production, habitat provisioning services, pollination, seed dispersal, resistance to wind storms, fire regulation and mitigation, pest regulation of native and invading insects, carbon sequestration, and cultural ecosystem services, in relation to forest type, structure and diversity. We also consider relationships between forest biodiversity and multifunctionality, and trade-offs among ecosystem services. We compare the concepts of ecosystem processes, functions and services to clarify their definitions. Our review of published studies indicates a lack of empirical studies that establish quantitative and causal relationships between forest biodiversity and many important ecosystem services. The literature is highly skewed; studies on provisioning of nutrition and energy, and on cultural services, delivered by mixed-species forests are under-represented. Planted forests offer ample opportunity for optimising their composition and diversity because replanting after harvesting is a recurring process. Planting mixed-species forests should be given more consideration as they are likely to provide a wider range of ecosystem services within the forest and for adjacent land uses. This review also serves as the introduction to this special issue of Biodiversity and Conservation on various aspects of forest biodiversity and ecosystem services

Alterations of DNA methylome in human bladder cancer

Bladder cancer is the fourth most common cancer in men in the United States, and its recurrence rate is highest among all malignancies. The unmet need for improved strategies for early detection, treatment, and monitoring of the progression of this disease continues to translate into high mortality and morbidity. The quest for advanced diagnostic, therapeutic, and prognostic approaches for bladder cancer is a high priority, which can be achieved by understanding the molecular mechanisms of the initiation and progression of this malignancy. Aberrant DNA methylation in single or multiple cancer-related genes/loci has been found in human bladder tumors and cancer cell lines, and urine sediments, and correlated with many clinicopathological features of this disease, including tumor relapse, muscle-invasiveness, and survival. The present review summarizes the published research on aberrant DNA methylation in connection with human bladder cancer. Representative studies are highlighted to set forth the current state of knowledge, gaps in the knowledgebase, and future directions in this prime epigenetic field of research. Identifying the potentially reversible and ‘drugable’ aberrant DNA methylation events that initiate and promote bladder cancer development can highlight biological markers for early diagnosis, effective therapy and accurate prognosis of this malignancy