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Objective To investigate the role pituitary adenylate cyclase activating polypeptide (PACAP) in the growth modulation of PACAP of human pancreas carcinoma cells and determine whether sphingomyolin (SM) may act as a second messenger involved in the postreceptor signal transduction. Methods Human pancreas carcinoma cell strains, JF305, HS766T and ASPC 1 cells were cultivated, reproduced and then treated with PACAP 1 38 (10 -12 -10 -6 M). The amounts of proliferated carcinoma cells were estiimated with Mosmann's method (MTT). The concentrations of intracellular SM in cells were determined with thin layer chromotograph. Intracellular adenosine monophosphate and Ca 2+ levels were detected by radioimmunoassay and Fura 2/AM respectively. Results It was found that three kind of human pancreatic cancer cells were proliferated and the intracellular levels of SM, cAMP and cytosolic Ca 2+ were increased by treating PACAP 1 38 . The effect of PACAP 1 38 in JF305, HS766T and ASPC 1 could be inhibited by Somatostatin. Conclusion PACAP 1 38 may play a role in the proliferation of human pancreatic cancer cells. The postreceptorsignal transduction of PACAP may be mediated by both adenosine cyclinase and Calcium calmodin pathways. SM may be a second messenger involved in this process.
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Objective:Our purpose was to investigate the growth regulation and postreceptor signal transduction of somatostatin (SS) on human colon cancer cell line. Methods:Low differentiated clone A cells of human carcinoma were treated with different concentrations of SS and the growth status was observed. Intracellular 1,4,5-trisphosphate (IP3) and cyclic adenosine monophosphate (cAMP) were extracted, then the concentrations of them were measured by liquid scintillation technique and gamma scintillation counter.Intracellular free calcium concentration was detected by loading Fura-2 and fluorescental technique. Protein kinase C (PKC) was extracted from cytosol and membrane, then the activity of both parts was determined with TaKai method. Results:The clone A cell growth was inhibited greatly by different concentrations of SS (10-10 to 10-5 mol/L) and it is related to the doses of SS.Somatortatin could largely inhibit the production of intracellular IP3, ［Ca2+］i, and cAMP, and decrease the activity of PKC. Conclusion:The growth of Clone A cell can be inhibited by SS. The inhibition may be mediated by phosphate inositol pathway, so intracellular IP3, ［Ca2+］i decreased, or inhibited the cell growth by inhibiting the activity of PKC.On the other hand, the cell proliferation may be inhibited by adenosine cyclase pathway, that is decreasing intracellular cAMP ,inhibiting cAMP-depending protein kinase.
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Objective To investigate the role pituitary adenylate cyclase-activating polypeptide (PACAP) in the growth modulation of PACAP of human pancreas carcinoma cells and determine whether sphingomyolin (SM) may act as a second messenger involved in the postreceptor signal transduction. Methods Human pancreas carcinoma cell strains, JF305, HS766T and ASPC-1 cells were cultivated, reproduced and then treated with PACAP1-38 (10- 12 - 10- 6 M). The amounts of proliferated carcinoma cells were estiimated with Mosmann's method (MTT). The concentrations of intracellular SM in cells were determined with thin layer chromotograph. Intracellular adenosine monophosphate and Ca2 + levels were detected by radioimmunoassay and Fura-2/AM respectively. ResultsIt was found that three kind of human pancreatic cancer cells were proliferated and the intracellular levels of SM, cAMP and cytosolic Ca2+ were increased by treating PACAP1-38. The effect of PACAP1-38 in JF305, HS766T and ASPC-1 could be inhibited by Somatostatin.ConclusionPACAP1-38 may play a role in the proliferation of human pancreatic cancer cells. The postreceptorsignal transduction of PACAP may be mediated by both adenosine cyclinase and Calcium-calmodin pathways. SM may be a second messenger involved in this process.
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ObjectiveTo observe the growth inhibition of somatostatin (SS) on human pancreas carcinoma cell strains HS766T and its mechanism.MethodsHS766T cells cultured in DMEM medium containing 10% FCS were treated with SS.Proliferation and viability of cell was measured by the Mosmann′s method (MTT). Intracellular adenosine monophosphate levels was detected by radioimmunoassay. Intracellular Ca 2+ level were measured using a F-2000 flurorescence spectrophotometer.ResultsSS inhibited the proliferation of HS766T in a concentration dependent manner (P