AIM: To investigate the mechanism of α-fetoprotein (AFP)in escaping from the host immune surveillance of hepatocellular carcinoma.METHODS: AFP purified from human umbilical blood was administrated into the cultured h...AIM: To investigate the mechanism of α-fetoprotein (AFP)in escaping from the host immune surveillance of hepatocellular carcinoma.METHODS: AFP purified from human umbilical blood was administrated into the cultured human lymphoma Jurkat T cell line or hepatoma cell line, Bel7402 in vitro. The expression of tumor necrosis factor related apoptosisinducing ligand (TRAIL) and its receptor (TRAILR) mRNA were analyzed by Northern blot and Western blot wasused to detect the expression of Fas and Fas ligand (FasL)protein.RESULTS: AFP (20 mg/L) could promote the expression of FasL and TRAIL, and inhibit the expression of Fas and TRAILR of Bel7402 cells. For Jurkat cell line, AFP could suppress the expression of FasL and TRAIL, and stimulate the expression of Fas and TRAILR. AFP also could synergize with Bel7402 cells to inhibit the expression of FasL protein and TRAIL mRNA in Jurkat cells. The monoclonal antibody against AFP (anti-AFP) could abolish these functions of AFP.CONCLUSION: AFP is able to promote the expression of FasL and TRAIL in hepatoma cells and enhance the expression of Fas and TRAILR in lymphocytes. These could elicit the escape of hepatocellular carcinoma cells from the host's lymphocytes immune surveillance.展开更多
AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polype...AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polypeptidefragment of antigen determinate with 12 amino acidsresidues was synthesized. Monoclonal antibody against thispeptide fragment was prepared. Proliferation of Mouse NS-L cells treated with methionine enkephalin of 1x10-6 mol.L-1was observed. The activities of protein kinase A (PKA) andprotein kinase C (PKC) were measured and thereby themechanism of effect of methionine enkephalin was postulated.RESULTS: The results demonstrated that methionineenkephalin could enhance the proliferation of NS-1 cells andthe effect of methionine enkephalin could be particularlyblocked by monoclonal antibody. The activity of PKA wasincreased in both cytosol and cell membrane. With referenceto PKC, the intracellular activity of PKC in NS-1 cells waselevated at 1x10-7 mol.L-1 and then declined gradually asthe concentration of methionine enkephalin was raised. Theeffects of methionine enkephalin might be reversed by bothnaloxone and monoclonal antibody.CONCLUSION: Coupled with the findings, it in-dicates thatthe signal transduction systems via PKA and PKC are involvedin the effects of methionine enkephalin by binding with thetraditional opioid receptors, and therefore resulting in differentbiological effects.展开更多
基金Supported by the National Natural Science Foundation of China,No. 30260117 and 30271174 the Natural Science Foundation of Hainan Province, No. 30315 the Educational Key Foundation of Hainan Province, No. 200322 the Nursery Foundation of Hainan Medical College, No. 200202
文摘AIM: To investigate the mechanism of α-fetoprotein (AFP)in escaping from the host immune surveillance of hepatocellular carcinoma.METHODS: AFP purified from human umbilical blood was administrated into the cultured human lymphoma Jurkat T cell line or hepatoma cell line, Bel7402 in vitro. The expression of tumor necrosis factor related apoptosisinducing ligand (TRAIL) and its receptor (TRAILR) mRNA were analyzed by Northern blot and Western blot wasused to detect the expression of Fas and Fas ligand (FasL)protein.RESULTS: AFP (20 mg/L) could promote the expression of FasL and TRAIL, and inhibit the expression of Fas and TRAILR of Bel7402 cells. For Jurkat cell line, AFP could suppress the expression of FasL and TRAIL, and stimulate the expression of Fas and TRAILR. AFP also could synergize with Bel7402 cells to inhibit the expression of FasL protein and TRAIL mRNA in Jurkat cells. The monoclonal antibody against AFP (anti-AFP) could abolish these functions of AFP.CONCLUSION: AFP is able to promote the expression of FasL and TRAIL in hepatoma cells and enhance the expression of Fas and TRAILR in lymphocytes. These could elicit the escape of hepatocellular carcinoma cells from the host's lymphocytes immune surveillance.
基金National Science Foundation of China,No.30060091
文摘AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polypeptidefragment of antigen determinate with 12 amino acidsresidues was synthesized. Monoclonal antibody against thispeptide fragment was prepared. Proliferation of Mouse NS-L cells treated with methionine enkephalin of 1x10-6 mol.L-1was observed. The activities of protein kinase A (PKA) andprotein kinase C (PKC) were measured and thereby themechanism of effect of methionine enkephalin was postulated.RESULTS: The results demonstrated that methionineenkephalin could enhance the proliferation of NS-1 cells andthe effect of methionine enkephalin could be particularlyblocked by monoclonal antibody. The activity of PKA wasincreased in both cytosol and cell membrane. With referenceto PKC, the intracellular activity of PKC in NS-1 cells waselevated at 1x10-7 mol.L-1 and then declined gradually asthe concentration of methionine enkephalin was raised. Theeffects of methionine enkephalin might be reversed by bothnaloxone and monoclonal antibody.CONCLUSION: Coupled with the findings, it in-dicates thatthe signal transduction systems via PKA and PKC are involvedin the effects of methionine enkephalin by binding with thetraditional opioid receptors, and therefore resulting in differentbiological effects.
