IGFBP-3 hypermethylation-derived deficiency mediates cisplatin resistance in non-small-cell lung cancer

Investigation of griffithsin's interactions with human cells confirms its outstanding safety and efficacy profile as a microbicide candidate

Many natural product-derived lectins such as the red algal lectin griffithsin (GRFT) have potent in vitro activity against viruses that display dense clusters of oligomannose N-linked glycans (NLG) on their surface envelope glycoproteins. However, since oligomannose NLG are also found on some host proteins it is possible that treatment with antiviral lectins may trigger undesirable side effects. For other antiviral lectins such as concanavalin A, banana lectin and cyanovirin-N (CV-N), interactions between the lectin and as yet undescribed cellular moieties have been reported to induce undesirable side effects including secretion of inflammatory cytokines and activation of host T-cells. We show that GRFT, unlike CV-N, binds the surface of human epithelial and peripheral blood mononuclear cells (PBMC) through an exclusively oligosaccharide-dependent interaction. In contrast to several other antiviral lectins however, GRFT treatment induces only minimal changes in secretion of inflammatory cytokines and chemokines by epithelial cells or human PBMC, has no measureable effect on cell viability and does not significantly upregulate markers of T-cell activation. In addition, GRFT appears to retain antiviral activity once bound to the surface of PBMC. Finally, RNA microarray studies show that, while CV-N and ConA regulate expression of a multitude of cellular genes, GRFT treatment effects only minimal alterations in the gene expression profile of a human ectocervical cell line. These studies indicate that GRFT has an outstanding safety profile with little evidence of induced toxicity, T-cell activation or deleterious immunological consequence, unique attributes for a natural product-derived lectin.

Identification and validation of highly frequent CpG island hypermethylation in colorectal adenomas and carcinomas

In our study, whole-genome methylation arrays were applied to identify novel genes with tumor specific DNA methylation of promoter CpG islands in pre-malignant and malignant colorectal lesions. Using a combination of Illumina HumanMethylation27 beadchips, Methylation-Sensitive High Resolution Melting (MS-HRM) analysis, and Exon arrays (Affymetrix) the DNA methylation pattern of ∼14,000 genes and their transcript levels were investigated in six normal mucosas, six adenomas and 30 MSI and MSS carcinomas. Sixty eight genes with tumor-specific hypermethylation were identified (p < 0.005). Identified hypermethylated sites were validated in an independent sample set of eight normal mucosas, 12 adenomas, 40 MSS and nine MSI cancer samples. The methylation patterns of 15 selected genes, hypermethylated in adenomas and carcinomas (FLI1, ST6GALNAC5, TWIST1, ADHFE1, JAM2, IRF4, CNRIP1, NRG1 and EYA4), in carcinomas only (ABHD9, AOX1 and RERG), or in MSI but not MSS carcinomas (RAMP2, DSC3 and MLH1) were validated using MS-HRM. Four of these genes (MLH1, AOX1, EYA4 and TWIST1) had previously been reported to be hypermethylated in CRC. Eleven genes, not previously known to be affected by CRC specific hypermethylation, were identified and validated. Inverse correlation to gene expression was observed for six of the 15 genes with Spearman correlation coefficients ranging from -0.39 to -0.60. For six of these genes the altered methylation patterns had a profound transcriptional association, indicating that methylation of these genes may play a direct regulatory role. The hypermethylation changes often occurred already in adenomas, indicating that they may be used as biomarkers for early detection of CRC.

The role of epigenetics in resistance to Cisplatin chemotherapy in lung cancer

Non-small cell lung cancer (NSCLC) is the most common cause of cancer related death in the world. Cisplatin and carboplatin are the most commonly used cytotoxic chemotherapeutic agents to treat the disease. These agents, usually combined with drugs such as gemcitabine or pemetrexed, induce objective tumor responses in only 20-30% of patients. Aberrant epigenetic regulation of gene expression is a frequent event in NSCLC. In this article we review the emerging evidence that epigenetics and the cellular machinery involved with this type of regulation may be key elements in the development of cisplatin resistance in NSCLC.

[DNA methylation and non-small cell lung cancer]

基因组DNA甲基化是目前发现的最主要的一种表观遗传修饰形式，高甲基化（hypermethylation）的DNA染色质构象发生改变，导致抑癌基因转录失活，在肿瘤发生发展中具有重要意义。近年来，DNA甲基化在肺癌，主要是非小细胞肺癌（non-small cell lung cancer, NSCLC）的研究中取得较大进展，为NSCLC早期诊断、风险评估、预后判断和干预治疗提供了新的靶点。