Hypermethylated CD36 gene affected the progression of lung cancer

Our study aimed to explore the relationship between CD36 methylation and the development of lung cancer and investigate the effect of combine treatment of Decitabine and Chidamide in lung cancer.

The differentially expression genes in tumor samples and normal samples were determined by microarray analysis. Weighted gene co-expression network analysis (WGCNA) was utilized to analyze gene expression data of lung cancer and the hub genes were screened in the modules. Methylation-specific PCR (MSP) was conducted to detect the methylation level of CD36 in lung cancer cells. QRT-PCR analysis and western blotting were performed to explore the relative mRNA expression and protein level. MTT assays, wound healing assay, Transwell assays and flow cytometry were conducted to clarify the cell proliferation, migration, invasion and cell cycle of lung carcinoma cell lines in vitro respectively. By xenograft and immunohistochemistry, the effect of co-treatment of Decitabine and Chidamide was further verified in vivo.

The heatmap displayed that the top 20 differential mRNA-expression gene in lung cancer tissues and normal tissues in which CD36 was low expressed in the tumor samples and high expressed in the normal samples. By WGCNA, CD36 was selected to be the hub gene in the brown module. And then CD36 was confirmed to be differential expressed and hypermethylated in lung cancer through qRT-PCR and western blotting. CD36 inhibited the lung cancer cell proliferation, promoted cell apoptosis, blocked cell cycle at G0/G1 phase, and inhibited cell migration. What's more, we found that Decitabine (DCTB) and Chidamide (CDM) co-treatment induced de-methylation and re-expression of silenced CD36 by conducting the vivo experiments. DCTB + CDM co-treatment synergistically suppressed tumor growth.

Our results showed that the high methylation of CD36 in lung cancer played an important role in the procession of lung cancer and Decitabine joint Chidamide had obvious effect of inhibiting the growth of lung tumor.