CpG methylation analysis of tumour suppressor gene and expression of Cathepsin B in renal cell carcinoma

Abstract

Renal cell carcinoma (RCC) is one of the most common types of cancers, representing about 2.3% of all malignancies throughout the world. In RCC, Cathepsin B (CtsB) plays a major role in signalling pathways, processing, and intracellular protein degradation. CtsB is involved in tumour cell invasion, matrix remodelling and metastasis and this mechanism was controlled by natural inhibitors. In this study targeted methylation changes were analyzed in primary renal cancer and metastatic tissues and the expression of CtsB was analyzed in RCC and compared with normal cells. The levels of CpG methylation of Runt-trelated transcription factor 3 (RUNX3) were analyzed. The decreased level of RUNX3 was observed in metastatic tissues due to CpG methylation. The increased methylation in CpG islands increased metastasis and was associated with RUNX3. The amount of CtsB mRNA was high in the RCC tissues than in surrounding normal tissues. Increased expression of CtsB was observed in RCC. Overexpression of CtsB was confirmed by Western blotting analysis and expression of CtsB increased the proliferation of RCC. The present finding revealed that CtsB has a major role in the development and proliferation of RCC.

Keywords

• Renal cell carcinoma
• CpG methylation
• Cathepsin B expression
• Metastasis