BACKGROUND: The tumor susceptibility gene 101 (TSG101) was originally identified as a tumor-suppressor gene that mediates many molecular and biological processes, such as ubiquitination, endosomal trafficking, cell survival, and virus budding, but its role in hepatocellular carcinoma (HCC) is currently unknown.

MATERIAL AND METHODS: We assessed the expression of TSG101 in HCC and paracancerous tissues using qPCR. Then, we used the TSG101-specific siRNA mix to disrupt the expression of TSG101 to investigate the subsequent effect on human hepatoma-7 (Huh7) cells. Western blot was used to detect the protein expression of TSG101 and other molecules. Cell growth assay was performed using CCK8. Transwell assay was used to investigate the migration and invasion ability of Huh7 cells after transfection with of TSG101 siRNA. Flow cytometry was used to estimate the effect of TSG101 knockdown on cell cycle and apoptosis. Confocal laser scanning microscopy was used to observe the actin filaments change and the formation of autophagy.

RESULTS: TSG101 was over-expressed in HCC tissues. TSG101 silence was able to suppress Huh7 cell proliferation, migration, and invasion. Furthermore, silencing of TSG101 could induce cell cycle arrest at G1 phase and inhibit the expression of cyclin A and cyclin D, while up-regulating the expression of CDK2. The mechanism might be induction of autophagic cell death and inactivation of Akt and ERK1/2.

CONCLUSIONS: TSG101 plays an important role in the development of HCC and may be a target for molecular therapy.

Keywords: Carcinoma, Hepatocellular - therapy, Autophagy - genetics, Cell Cycle Checkpoints - genetics, Cell Death, Cyclin A - metabolism, Cyclin D - metabolism, DNA-Binding Proteins - physiology, Endosomal Sorting Complexes Required for Transport - physiology, G1 Phase, Gene Deletion, Gene Silencing, Microscopy, Confocal, Microscopy, Fluorescence, RNA, Small Interfering - metabolism, Transcription Factors - physiology