[The molecular mechanism of survivin expression in activated human peripheral lymphocytes].

AIM: Investigate the molecular mechanism of regulating survivin expression and related signal transduction pathway, molecular cascade reaction and biological effects in activated PBMC. METHODS: The expression of survivin and related proteins were detected by Western blot in PBMC stimulated by PHA and rhIL-2 with or without JAK inhibitor-AG490 treatment, and FCM was performed to analyze cell cycle and cell division. RESULTS: Our results indicated that molecular and cellular reactions in PBMC activated by PHA and rhIL-2 were dependent on time series. At first, the phosphorylation of Stat3 and Stat5 were observed, then, protein levels of CyclinD3 and CyclinE increased, and the stimulated PBMC began to enter to S phage with survivin protein expression was initiated, which at last resulted in cell division with dramatically increasing expression of survivin protein. AG490 could significantly inhibit all these reactions but had no effect on the expressions of the cell cycle inhibitor-P21 and anti-apoptosis protein-Bcl-2. CONCLUSION: The expression of survivin in stimulated PBMC was dependent on the primarily activated JAK-STAT pathway, which upregulated CyclinD3 and CyclinE protein levels, initiated the cell cycle progression, and induced cell cycle-dependent survivin expression, and so survivin was involved in cell division and cell proliferation.

[The mechanisms of p21WAF1/Cip-1 expression in MOLT-4 cell line induced by TSA].

To investigate the function and molecular mechanism of p21(WAF1/Cip-1) expression in MOLT-4 cells induced by HDAC inhibitor TSA, the expression pattern of p21(WAF1/Cip-1) and the distribution of cell cycle in TSA treated cells were analyzed. The results showed that TSA could effectively induce G(2)/M arrest and apoptosis of MOLT-4 cells. Kinetic experiments demonstrated that p21(WAF1/Cip-1) were upregulated quickly before cell arrested in G(2)/M and began decreasing at the early stage of apoptosis. Meanwhile, the proteasome inhibitor MG-132 could inhibit the decrease of p21(WAF1/Cip-1) at the early stage of apoptosis, which showed that proteasome pathway involved in p21(WAF1/Cip-1) degradation during the TSA induced G(2)/M arrest and apoptosis responses. This study also identified that the protein level of p21(WAF1/Cip-1) was highly associated with the cell cycle change induced by TSA. Compared to cells treated by TSA only, exposure MOLT-4 cells to TSA meanwhile treatment with MG-132 increased the protein level of p21(WAF1/Cip-1) and increased the numbers of cell in G(2)/M-phase, whereas the cell apoptosis were delayed. It is concluded that p21(WAF1/Cip-1) plays a significant role in G(2)/M arrest and apoptosis signaling induced by TSA in MOLT-4 cells.