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RASSF1A expression inhibits the growth of hepatocellular carcinoma from Qidong County
Wan-Jiang Xue1, Chun Li, Xiao-Jun Zhou
1Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China.
Background And Aim:
The tumor-suppressing role of Ras-association domain family 1A (RASSF1A) has been described in several systems. In this study, we tested its tumor-suppressing ability and the potential molecular mechanisms in hepatocellular carcinoma (HCC) from Qidong County.
Methods:
Reverse transcription polymerase chain reaction and Northern blotting were employed to detect the expression of RASSF1A in HCC. After establishing stable RASSF1A (wild type or mutant) expressing 'qi dong gan ai yan jiu suo' ([Qidong Institute of Liver Cancer] QGY)-7703 cell lines, we tested the effects of RASSF1A expression on cell growth by cell proliferation rate, cell colony formation, and cell cycle progression. We also tested the effects of RASSF1A expression on tumorigenesis in nude mice and on cellular sensitivity to mitomycin treatment.
Results:
The RASSF1A transcript was not found in 75% (three of four) of HCC cell lines and 67% (32/48) of HCC primary biopsies. The stepwise regression analyses indicated that the loss of RASSF1A expression was more frequent in patients who were hepatitis B virus surface antigen positive (HBsAg+) compared to those who were HBsAg(-), both in tumor and corresponding non-cancerous tissues. The wild-type (wt)-RASSF1A expression in the QGY-7703 cell line resulted in fewer and smaller clones, decreased xenograft tumor volume and weight, and G(1)/S arrest in vitro and in vivo. The wt-RASSF1A expression also decreased the cyclin D1 protein expression, which appeared to be at the level of post-transcriptional control. In addition, the wt-RASSF1A expression increased cell growth inhibition and the percentage of cells with sub-G(1) DNA content when the cells were treated with mitomycin.
Conclusion:
RASSF1A is a tumor suppressor in HCC. The loss of RASSF1A expression may be related to HBsAg+ in hepatocarcinogenesis. Its inactivation may play an important role in the development of HCC.
Insights
Ras-association domain family 1A (RASSF1A) acts as a tumor suppressor in hepatocellular carcinoma (HCC). Loss of RASSF1A expression, potentially linked to hepatitis B virus surface antigen positivity, is implicated in HCC development.
Area of Science:
- Oncology
- Molecular Biology
- Hepatology
Background:
- Ras-association domain family 1A (RASSF1A) is a known tumor suppressor.
- Its role in hepatocellular carcinoma (HCC) and underlying mechanisms require further investigation, particularly in specific populations like those from Qidong County.
Purpose of the Study:
- To investigate the tumor-suppressing role of RASSF1A in HCC.
- To elucidate the molecular mechanisms involved in RASSF1A's function in HCC development.
- To explore the association between RASSF1A expression and hepatitis B virus (HBV) infection status.
Main Methods:
- Detected RASSF1A expression in HCC cell lines and primary tumors using reverse transcription polymerase chain reaction and Northern blotting.
- Established stable RASSF1A-expressing cell lines (wild-type and mutant) for functional studies.
- Assessed the impact of RASSF1A on cell proliferation, colony formation, cell cycle progression, tumorigenesis in nude mice, and sensitivity to mitomycin treatment.
Main Results:
- RASSF1A transcript was absent in 75% of HCC cell lines and 67% of primary HCC biopsies.
- Loss of RASSF1A expression was significantly associated with hepatitis B virus surface antigen positivity (HBsAg+).
- Wild-type RASSF1A expression suppressed tumor growth, induced G1/S cell cycle arrest, reduced cyclin D1 protein, and enhanced sensitivity to mitomycin.
Conclusions:
- RASSF1A functions as a tumor suppressor in HCC.
- Loss of RASSF1A expression may be linked to HBsAg+ status during hepatocarcinogenesis.
- RASSF1A inactivation plays a crucial role in the pathogenesis of HCC.
