Abstract:Objective To investigate the expression of progestin and adipoq receptor family member 3 (PAQR3) in colon cancer cell lines and detection of the aberrant methylation status in its promoter, and to detect the demethylating effect of procaine hydrochloride (PCA). Methods The mRNA expression of PAQR3 in colon cancer cell lines (SW620, COLO205, SW480) was detected by realtime-PCR (RT-PCR). The promoter methylation status of PAQR3 in colon cancer cells and the methylation status after drug treatment were detected by methylationspecific PCR. The expression of PAQR3 protein in procaine hydrochloride treating SW480 cells was detected by western blot. Results The expression of PAQR3 was decreased in three colon cancer cells, the difference was statistically significant (P < 0.05), and the expression of SW620 was lower than COLO205 and SW480 (P < 0.05); the methylationspecific amplification product bands of PAQR3 gene were observed in all three colon cancer cell lines, and the difference in methylation percentage was statistically significant (P < 0.05). Compared with SW620 cells, the percentage of PAQR3 methylation was significantly lower in SW480 and COLO205 cells (P < 0.05); methylation-specific amplification product bands and non-methylation-specific amplification bands were observed in the three colon cancer cell lines treated with procaine hydrochloride, and the percentage of PAQR3 methylation was significantly decreased in the three cells, and the difference was statistically significant (P < 0.05). There was a statistically significant difference in the relative expression of PAQR3 protein between the control group and the procaine hydrochloride treatment group (P < 0.05). Compared with the control group, the PAQR3 protein in the procaine hydrochloride treatment group was increased (P < 0.05). Conclusions The relative expression of PAQR3 mRNA in colon cancer cells was significantly decreased, which may be related to its promoter methylation. PCA can partially reverse the methylation status of PAQR3 in colon cancer cell lines and up-regulate the expression of PAQR3 protein.