Decitabine regulates the resistance of Hep3B to sorafenib through demethylation

Abstract Purpose：To investigate the mechanism of drug resistance in hepatocellular carcinoma treated with sorafenib from an epigenetic perspective , and to examine the effect of Sorafenib sensitivity on hepatocellular carcinoma after in vitro and vivo combination with the epigenetic drug decitabine . This research aims to provide new ideas and methods for the clinical treatment of hepatocellular carcinoma. Methods: Using the GEPIA 2 database, the expression of organic anion transporting polypeptide 1B3 (OATP1B3) gene in different tumors and adjacent normal tissues of 508 patients with primary hepatocellular carcinoma (HCC) was retrieved. The Kaplan-Meier method was used to perform survival analysis by grouping based on the expression levels of this gene.. Using the TCGA-LIHC dataset to analyze the correlation between SLCO1B3 and DNMTs. Additionally, OATP1B3 promoter methylation levels were detected in Hep3B, HepG2, SNU182, LM3, HUH7, and SNU387 cells using bisulfite methylation data. The expression of OATP1B3 was assessed by RT-qPCR and Western Blot. The effect of Sorafenib in combination with DAC on the proliferation of Hep3B cells was dynamically monitored using RTCA-eSight. The mechanism was further verified in vivo using an in situ implantation tumor model in nude mice. The expression of OATP1B3 in tumor tissues was detected by immunohistochemical staining and Western Blot. Results: Individuals with high expression of the OATP1B3 gene have a significantly higher overall survival rate than individuals with low expression. The negative correlation between SLCO1B3 expression and the DNA methyltransferase DNMT1.In Hep3B,the DNA methylation of OATP1B3 results in decreased protein expression. After DAC incubation, OATP1B3 expression was up-regulated. Following DAC administration, Hep3B proliferated at a considerably lesser rate than the Sorafenib group. The absorption of Sorafenib by Hep3B was raised by 1.87-fold following co-administration of DAC. According to the Hep3B xenograft nude mice model data, the tumor sizes in the combination group were all noticeably lower after 21 days of dosing than those in the Sorafenib alone, DAC, and Control groups. Both the combination group and the DAC group had significantly greater levels of OATP1B3 expression than control and Sorafenib group. Conclusion: By inhibiting the DNA methylation of SLCO1B3 and increasing the expression of OATP1B3, which mediates Sorafenib transmembrane transporter protein, the epigenetic drug decitabine can enhance the accumulation of Sorafenib in hepatocellular carcinoma cells. This enhances sensitivity in hepatocellular carcinoma cells and reverses resistance to Sorafenib.