Objective To investigate the growth inhibition and the apoptosis inducement effects of polysaccharide of trametes robiniophila murr (PS-T) on human rectal cancer cell line HR8348 and elucidate the possible mechanisms. Methods After treatment with PS-T, the growth inhibition rate of human rectal cancer cell strain HR8348 was studied by MTT method. The apoptotic index was detected by methyl green and pyronine Y staining and by terminal deoxynucleotidyl transferase(TdT) mediated dUTP nick end labeling (TUNEL). The bcl-2, bcl-xl, bax, bak and p53 gene expressions of HR8348 cells were examined by immunohistochemical method.Results PS-T induced a dosedependent inhibition of HR8348 cells in vitro. The maximum percentage of growth inhibition was 71.1% by 36 h after administration of PS-T at a concentration of 4.0 mg/ml. There was no significant difference in the inhibitory rate as compared to the positive control (5-FU 10 μg/ml, P gt;0.05). The typical apoptosis phenomenons were observed under the light microscope by both staining methods. The apoptotic index increased parallelling with the increase of concentration of PS-T. When the PS-T concentration was 4.0 mg/ml, the apoptotic index determined by methyl green and pyronine Y staining and by TUNEL method increased rapidly to 0.1620±0.0128 and 0.2612±0.0158, respectively, which was greater than that of the positive control (5-FU 10 μg/ml, P lt;0.05). The expression of bcl-2, bcl-xl, bak and p53 was increased in the PS-Ttreated HR8348 cells by 36 h, while the bax remained unchanged. Expression index of bak/bcl-2 and bak/bcl-xl was increased significantly as compared with the control (P lt;0.05). Conclusion PS-T can significantly inhibit growth and induce apoptosis of human rectal cancer cell strain HR8348 in vitro. The apoptosis induced by PS-T might be related to the increase of the ratio of bak to bcl-2 and to bcl-xl and upregulation of the expression of p53 gene.
Citation: CHENG Ruochuan,TANG Ligui,LAN Liqin,JIA Wei. Study on Apoptosis of Human Rectal Adenocarcinoma Cell Line HR8348 Induced by Polysaccharide of Trametes Robiniophila Murr in Vitro. CHINESE JOURNAL OF BASES AND CLINICS IN GENERAL SURGERY, 2003, 10(6): 568-571. doi: Copy