PTPIP51 mRNA and protein expression in tissue microarrays and promoter methylation of benign prostate hyperplasia and prostate carcinoma.

BACKGROUND: Protein tyrosine phosphatase interacting protein 51 (PTPIP51) shows a tissue-specific expression pattern and is associated with cellular differentiation and apoptosis in several mammalian tissues. Overexpression of the full-length protein enhances apoptosis. It is also expressed in various carcinomas. In this study the expression of PTPIP51 and its in vitro interaction partners was investigated in human benign prostate hyperplasia (BPH) and in prostate carcinoma (PCa). METHODS: Tissue microarrays of human BPH and PCa were analyzed by immunohistochemistry. For polymerase chain reaction (PCR), cryo samples of BPH and PCa were used. Bisulfite DNA treatment, followed by sequencing of PCR products was performed in order to analyze CpGs methylation within the promoter region of the PTPIP51 gene. RESULTS: PTPIP51 mRNA and protein expression was detected in prostatic epithelia of BPH and in tumor cells of PCa, respectively, and within smooth muscle cells of the stromal compartment. A stronger expression was present in nerve fibers, particularly in PCa, in immune cells and in smooth muscle and endothelial cells of vessels of BPH and PCa. On mRNA levels, a slightly elevated expression of PTPIP51 was observed in the PCa group as tested by real-time quantitative PCR analyses. Methylation experiments revealed that at least 70% of methylated CpGs in the CpG island of the PTPIP51 gene promoter region were identified in BPH samples. In contrast, a loss of methylation has been found in the PCa group. CONCLUSION: The promoter methylation status of PTPIP51 seems to influence the expression of PTPIP51, which was seen as elevated in the PCa.

Aberrant epigenetic modifications in the CTCF binding domain of the IGF2/H19 gene in prostate cancer compared with benign prostate hyperplasia.

Expression of the imprinted genes insulin-like growth factor 2 (IGF2) and H19 depends on the methylation pattern of their common imprinting control region (ICR) located on chromosome 11p15. As the somatic imprinting pattern may be lost during tumorigenesis due to epigenetic alterations, in the present study, we analyzed the DNA methylation and histone modifications in the differentially methylated region (DMR) of IGF2/H19 in benign prostate hyperplasia (BPH) and prostate carcinoma (PCa). Sodium bisulfite sequencing was performed on frozen tissue collected after radical prostatectomy. Thirty tumors and 17 non-cancerous tissue samples were analyzed. Histological diagnosis was, in addition, confirmed by amplification of the epithelial tumor marker alpha-methylacyl coenzyme-A racemase. Chromatin immunoprecipitation assay (ChIP) was carried out on sonificated chromatin from fresh tissue samples from 10 PCa, 10 BPH using antibodies against trimethyl histone H3K9, dimethyl histone H3K9, trimethyl H3K27 and acetyl H3K9. The methylation pattern of 17 CpGs within 227 bp of the H19 fragment was characterized from each DNA sample. All (BPH) samples demonstrated >80% methylation of CpGs. In contrast, we found 41% of CpGs methylated in 9 out of 30 PCa specimens. We observed statistically significant differences in the methylation state between PCa and BPH groups, especially in the DMR of H19 (p<0.0001) and in the ICR (p=0.0034), which corresponds to CTCF binding domain. ChIP assay revealed that dimethyl H3K9 is associated with the ICR of IGF2/H19 in BPH, but not in PCa (p<0.0001). Our data demonstrate that DNA methylation and histone methylation analysis of the ICR within the DMR of IGF2/H19 provides important insights into early steps of carcinogenesis and, therefore, may contribute to improving diagnosis of PCa.

The function of interleukin 17 in the pathogenesis of rheumatoid arthritis.

Interleukin (IL)-17 is a 30- to 35-kDa homodimeric polypeptide cytokine cloned in 1993 and originally named cytotoxic T lymphocyte-associated antigen-8 (CTLA-8). Sequencing the human genome resulted in the discovery of an additional five members of the IL-17 family that were consecutively named IL-17B to IL-17F. IL-17A is exclusively produced by a newly identified CD4+ T-helper subset that was recently named Th17. Differentiation of these cells from naive CD4+ T cells requires both TGF-beta and IL-6. IL-15 and, especially, IL-23 are required for these cells' survival and efficient IL-17 production. IL-17 binding to an IL-17 receptor expressed on epithelial, endothelial, and fibroblastic stromal cells triggers the activation of transcription factor NF-kappaB and mitogen-activated protein kinase (p-38), which in turn results in the secretion of IL-1, TNF-alpha, IL-6, IL-8, or prostaglandin E2. The IL-17 family plays a key role in the regulation of immune and inflammatory response, in the homeostasis of several tissues, and the progression of autoimmune diseases. In addition, IL-17 exerts synergistic effects with TNF-alpha and IL-1 in the induction of joint inflammation and cartilage and joint destruction. Given these properties, it is not surprising that in certain pathological conditions, for example rheumatoid arthritis, Th17 cells emerge as a new pathological cell type that, by IL-17 production and release, contributes to their pathogeneses.