[Mechanism of receptor for retinoids inducing apoptosis of human melanoma cell line A375].

OBJECTIVE: To investigate the mechanism of receptors for retinoids inducing apoptosis of human melanoma cell line A375. METHODS: The effects of 3 kinds of retinoids (9-cis-RA, at-RA and 13-cis-RA), of TTNPB (RAR agonist) and of Methoprene acid (Ma, RXR agonist) on apoptosis of A375 cells were studied by detecting the expression of Bcl-2/Bax and by using. Annexin V/PI staining analysis, TUNEL detection and active Caspase-3 analysis. RESULTS: Retinoids and TTNPB could up-regulate the expression of Bax and down-regulate the expression of Bcl-2. The results of TUNEL and Annexin V/PI staining analysis showed that all of retinoids and TTNPB could induce apoptosis of A375 cells, compared with control group (P < 0.05); the effect of TTNPB was significantly greater than that of others (P < 0.05), but Ma was similar to the control (P > 0.05). Active Caspase-3 analysis showed that TTNPB and all of retinoids could up-regulate the expression of Caspase-3, and the effect of TTNPB was significantly greater than that of others (P < 0.05). CONCLUSION: Caspase-3 pathway is involved in the process for retinoids inducing apoptosis of A375 cells. The activation of RAR may have relation with retinoids inducing apoptosis of A375 cells, but may have no longer relation with RXR.

[Effects of bFGF and alpha-MSH on adhesion and migration of human melanocytes in vitro].

OBJECTIVE: To observe the effect of basic fibroblast growth factor (bFGF) and alpha-melanocyte stimulating hormone (alpha-MSH) on adhesion and migration of melanocytes in vitro. METHODS: Human melanocytes were obtained from normal human foreskins. Culture dishes covered with fibronectin were used to perform melanocytes adhesion assay, and cell motility was assessed using the Transwell micropore filter method. RESULT: bFGF and alpha-MSH increased melanocytes adhesion on culture dishes covered with fibronectin. bFGF stimulated melanocytes migration through micropore filter while alpha-MSH had no significant effects. CONCLUSION: bFGF and alpha-MSH could promote the adhesion and migration of melanocytes, which suggests that two agents may play a role in the repigmentation of vitiligo.

[Receptor-related mechanism of proliferation inhibilion and apoptosis induetion of human tongue squamous cell line Tca8113 by retinoids].

OBJECTIVE: To investigate the receptor-related mechanism of retinoids inhibiting proliferation and inducing apoptosis of human oral squamous cell carcinoma cell line Tca8113. METHODS: The effects of 3 retinoids (namely 9-cis-RA, at-RA and 13-cis-RA), TTNPB (RAR agonist) and methoprene acid (Ma, RXR agonist) on proliferation and cell cycle of Tca8113 cells were analyzed by MTT assay and flow cytometry. The roles of these agents in inducing apoptosis of Tca8113 cells were also evaluated by detecting the expression of Bcl-2/Bax, TUNEL and active caspase-3 analysis. RESULTS: Both retinoids and TTNPB could inhibit the proliferation of Tca8113 cells, and the effect of TTNPB was the most powerful in all the reagents, but MA had no such effect. At the concentration of 1 x 10(-5) mol/L, all the agents except for Ma could increase the percentage of G(1)/G(0)-stage cells after incubation of the cells for 24 h and 48 h. Retinoids and TTNPB could up-regulate the expression of Bax and down-regulate Bcl-2 expression. The results of TUNEL demonstrated that retinoids and TTNPB, but not Ma, could induce apoptosis of Tca8113 cells as compared with the control group (P<0.05). Except for Ma, all the agents up-regulated caspase-3 expression, and the effect of TTNPB was the strongest (P<0.05). CONCLUSIONS: Retinoids can suppress the proliferation of and induce apoptosis of Tca8113 cells, the effect of which involves activation of RAR but not RXR. caspase-3 pathway is involved in apoptosis-inducing effects of retinoids.