The Therapeutic Effect Of Tripeptide Tyroservatide (YSV) On Lung Carcinoma And Its Mechanism By Affecting Histone Acetylation Regulation On Cell Cycle

Objective:To explore the anticancer effect of tripeptide tyroservatide(YSV) on human lung carcinoma NCI-H292 cells and to approach its possible mechanism by affecting histone acetylation, arresting cell cycle and inducing apoptosis.Methods:1. The lung carcinoma cell line NCI-H292 was used to explore the effect of YSV on cell proliferation. In vitro effect was assayed by MTS method, and in vivo effect was assay by hollow fiber assay.2. The apoptosis-inducing function of YSV on human lung carcinoma NCI-H292 cells was assayed by AnnexinV/PI, DNA Ladder. The effect of YSV on cell cycle of human lung carcinoma NCI-H292 cells was assayed by FCM method.3. The effect of YSV on p21, p27 mRNA and protein expression in human lung carcinoma NCI-H292 cells were assayed by Real-time PCR and Western Blot methods.4. Western Blot was used to observed the effects of YSV on acetylated histones H3 and H4 expression in human lung carcinoma NCI-H292 cells; the activity of histone deacetylase (HDAC) in human lung carcinoma NCIH292 cells was assayed by fluorescence detection methods; the activity of histone acetylase (HAT) in human lung carcinoma NCI-H292 cells was assayed by spectrophotometer.5. Chromatin immunoprecipitation assay (ChIP) was used to observed the effects of YSV on histone acetylation of some regions of promoters of p21WAF1 and p27KIP1 gene in lung carcinoma NIC-H292.Results:1. YSV (0.2～3.2mg/ml in vitro and 160～320μg/kg/d in vivo) can remarkably inhibit growth of human lung carcinoma cells NCI-H292 (P<0.05).2. YSV (0.8,1.6mg/ml) could induce the apoptosis in NCIH292 cells:apoptotic cells amount in sample treated with YSV were more than that of control group; the DNA Ladders were detected in NCI-H292 cells treated with YSV. YSV could stop the cell cycle of tumor cells by remarkably increasing the percentage of S phase cells (P<0.05), decreasing the percentage of G2/M phase cells.3. YSV could increase the mRNA and protein expression of CDKI p21 and p27 in human lung carcinoma NCI-H292 cells (P<0.05).4. YSV can increase acetylated histones H3 and H4 expression (P<0.05), remarkably inhibit the HDAC activity, have no obvious effects on the HAT activity.5. YSV can cause an accumulation of acetylated histone H3 and H4 in p21WAF1 and p27KIP1 gene promoters associated region of chromation in lung carcinoma NIC-H292, activate the transcriptions of p21 and p27 gene, induce cell cycle arrest.Conclusion:YSV can inhibit the growth of lung carcinoma cells in vivo and in vitro, stop the cell cycle of tumor cells, and induce those cells apoptosis. The mechanism of its anticancer effect is as follows:YSV can inhibit HDAC activity, increase acetylated histones H3 and H4 expression, cause an accumulation of acetylated histone H3 and H4 in p21WAF1 and p27KIP1 gene associated region of chromation, then promote p21 and p27 expression, and so cell cycle of tumor cell can be affected. YSV can make NCI-H292 cells blocked in S phase, inhibit cell proliferation, and induce the apoptosis of tumor cell.