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Objective: to investigate the expression of c-jun-activation-domain binding protein (JAB1) in hepatocellular carcinoma (HCC) and the clinicopathologic significance thereof., Methods: Immunohistochemistry was used on 76 specimens of HCC tissues and native liver tissues adjacent to the HCC tissues, and 10 specimens of normal liver tissues near the liver angioma to detect the expression of JAB1 and the cell proliferative factor Ki67., Results: The expression rate of JAB1 in the HHC tissues was 68.85%, significantly higher than that in the adjacent liver tissues and normal liver tissues near liver angioma (38.72% and 34.36% respectively, both P < 0.001). The expression of JAB1 was correlated with the histological differentiation, serum alpha-fetoprotein level, and metastasis (P = 0.000, 0.015, and 0.000), but not with gender, age, tumor size, serum HBsAg, and existence of necrosis and cirrhosis. The expression rate of Ki67 protein in the HCC tissues was 41.45%, significantly higher than that in the adjacent liver tissues and normal liver tissues near liver angioma (2.11% and 2.01% respectively, both P < 0.001). There was a positive correlation between JAB1 and Ki67 (P < 0.001)., Conclusion: JAB1 is highly expressed in HCC and may play an important role in the oncogenesis and development of HCC. JAB1 may be used as a marker for neoplastic change in liver cells and thus has potential clinicopathologic value.

Objective: To study the effect of all-trans retinoic acid (ATRA) on U937 cell growth and its mechanism., Methods: Cell cycle was detected by flow cytometry (FCM), expressions of cell cycle associated protein and the p27 related protein were detected by Western blot. The binding of P27 and Skp2 was detected by immunoprecipitation., Results: FCM displayed that ATRA could inhibit the proliferation of U937 cells. At 72 h on 1 micromol/L ATRA treatment, 72% of the cells were arrested at G0/G1 phase. Western blot displayed that ATRA could decrease the expression of cyclin A, up-regulate the expression of p21 and p27, and down-regulate the expression of p27 related proteins Skp2. p27 could bind with Skp2 in U937 cells as detected by immunoprecipitation., Conclusion: ATRA may arrest the proliferation of U937 cells through the reduction of Skp2 expression, and finally the induction of the accumulation of p27.

Background & Objective: Arsenic trioxide (As(2)O(3)) is a new drug used to treat solid tumors. However, the mechanism is still unclear. This study was to investigate the effects of As(2)O(3) on the proliferation of human hepatocellular carcinoma (HCC) cell line SMMC-7721, and to explore the mechanisms., Methods: When treated with 0-8 micromol/L As(2)O(3) for 96 h, the survival rate of SMMC-7721 cells was determined by WST-8 assay. When treated with 2 micromol/L As(2)O(3) for 72 h, the expression of P27(kip1) and c-Jun activation domain-binding protein 1 (JAB1) in SMMC-7721 cells were detected at different time points by Western blot, the subcellular localization of P27(kip1) and JAB1 was detected by subcellular fractionation and immunofluorescent staining., Results: As(2)O(3) significantly inhibited the proliferation of SMMC-7721 cells. The 50% inhibition concentration (IC50) of As(2)O(3) to SMMC-7721 cells was (1.81+/-0.41) micromol/L at 96 h. When SMMC-7721 cells were treated with 2 mumol/L As(2)O(3) for 12 h, the expression of JAB1 was down-regulated and that of P27kip1 was up-regulated. Furthermore, P27(kip1) and JAB1 proteins were translocated from the cytoplasm into nuclei when cells were exposed to 2 micromol/L As(2)O(3) for 12 h and 24 h, respectively. The nuclear accumulation of both proteins was also observed under fluorescence microscope after treatment of 2 micromol/L As(2)O(3)., Conclusion: As(2)O(3) attenuates JAB1 expression, thereby disturbs the location and expression of P27(kip1), and may participate in regulating the proliferation of SMMC-7721 cells through interfering with the function of P27(kip1).