Arylamine N-acetyltransferases: a new inhibitor of apoptosis in HepG2 cells

Objective: To explore how arylamine N-acetyltransferases (NATs) is related to cell apoptosis. Methods: NAT activity in apoptotic HepG2 cells was measured using high performance liquid chromatography (HPLC); the apoptosis rate of HepG2 cells acted upon by an NAT inhibitor was measured using flow cytometry. Results: NAT activity was lowered in apoptotic HepG2 cells; apoptosis rate induced by camptothecin (CAM) increased after inhibition of NAT activity in HepG2 cells. Conclusion: NAT can inhibit apoptosis in HepG2 cells.

Antihepatocarcinoma Effect of Solanine and Its Mechanisms

Objective To explore the antitumor effect of solanine and its mechanisms.Methods The in vivo antitumor effect of solanine was observed using models developed through in vivo transplantation of tumor cells;In vitro lines of sensitive antitumor cells were selected from the digestive system using MTT assay;The effect of solanine on cell morphology was observed using transmission electronic microscopy;The morphology of apoptotic cells was observed using Annexin V/PI double staining and laser confocal scanning microscopy(LCSM);The rate of cell apoptosis was measured using Annexin V/PI double staining and flow cytometry;The concentration of intracellular Ca 2+ ([Ca 2+ ]i)was determined using Fluo-3/AM staining and LCSM;The membrane potential of cellular mitochondria was determined using TMRE staining and LCSM;The protein expression of Bcl-2 and Bax was measured using immunological marking and LCSM;And the activity of caspase-3 was measured using the colorimetric method.Results Solanine could inhibit the growth of tumor weight in S180 tumor-bearing mice and prolong the survival time of H22 tumor-bearing mice.MTT assay revealed that HepG2 cells were quite sensitive to solanine because solanine could induce morphological changes in HepG2 cells,with the rate of early apoptosis being 4%,8.5%,and 20.1%,for HepG2 cells treated for 24 h with solanine at concentration of 0.4,2,and 10μg/mL, respectively.Solanine could raise the[Ca 2+ ]i and lower the membrane potential.It could reduce the protein expression of Bcl-2 while increase that of Bax,thus increasing the activity of caspase-3.Conclusion The obvious antitumor activity of solanine in human hepatocarcinoma is demonstrated.This inhibitory effect is achieved through solanine decreasing the Bcl-2/Bax ratio,thus increasing[Ca 2+ ]i,which could enhance the enzymatic activity of the caspase family,thus inducing the apoptosis of HepG2 cells.