Effect of calprotectin subunit S100A9 on the expression and methylation of OCLN in human melanoma cell line A-375

Authors: MOSTAFA NAJAFI, SAFAR ALI ALIZADEH, MEHDI AZAD, TAGHI NASERPOUR FARIVAR, FARZAD RAJAEI, KOUROSH HOTAM SOROURI, BABAK RAHMANI, NEMATOLLAH GHEIBI

Abstract: Increased levels of calprotectin subunits S100A8 and S100A9 have been detected in human cancers. Melanoma is the most aggressive type of skin cancer, and its treatment is challenging because of its brain metastasis. OCLN encodes occludin, which plays a major role in the formation and regulation of tight junctions. The aim of this study was to evaluate the methylation status of the OCLN promoter and its expression in A-375 melanoma cells treated with or without various concentrations of S100A9 for 24, 48, and 72 h. Total RNA was extracted, and synthesized cDNA was assessed by performing real-time PCR. MSP-PCR was performed after treatment with bisulfite. Recombinant S100A9 inhibited the proliferation of the A-375 cell line and the expression of the OCLN gene was downregulated in a time- and concentration-dependent manner. Results of MSP-PCR showed that the OCLN gene promoter in a human melanoma cell line (A-375) was semimethylated.

Keywords: Melanoma, OCLN, calprotectin subunit S100A9, methylation, promoter

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