Investigation Into The Effect Of Hedgehog Signaling Pathway On Extracelluar Matrix Degradation Of Gastric Cancer

Objctive: We detected the expression of molecules of Hedgehog signaling pathway and Matrix Metalloproteinases in human gastric cancer to analyze their roles in the occurrence, progression, invasion, and metastasis of gastric cancer. Then human gastric cell lines SGC-7901 was used in study, we investigated the effect and molecule mechanism of Hedgehog signaling pathway on extracelluar matrix degradation of human gastric cancer SGC-7901 cells after Hedgehog signaling pathway being blocked with cyclopamine.Methods:(1)Immunohistochemistry was used to examine the expression of Shh, Gli1, MMP-2 and MMP-9 protein in 54 cases of human gastric cancer tissues and their adjacent tissues and 30 cases of normal gastric mucosa tissues.Then we analyzed the associativity among expression of Shh, Gli1, MMP-2, MMP-9 and clinical pathology characters in gasric cancer tissues.(2)After Hedgehog signaling pathway was blocked with cyclopamine specifically, the capacities of invasion and migration of SGC-7901 cells were examined by transwell chamber assay and wound healing assay respectively. Reverse-transcription polymerase chain reaction (RT-PCR) was used to detect the expression of MMP-2 and MMP-9 mRNA in SGC-7901 cells. Immunocytochemistry was used to detect the expression of MMP-2 and MMP-9 protein in SGC-7901 cells.Results:(1)The positive expression rates of Shh, Gli1, MMP-2 and MMP-9 in gastric cancer tissues were 68.52%(37/54), 61.11%(33/54), 55.56%(30/54), 64.81%(35/54), respectively, which were significantly higher than those in their adjacent tissues in where the positive expression rates of Shh,Gli1, MMP-2 and MMP-9 were 27.78%(15/54), 24.07%(13/54), 29.63%(16/54), 22.22%(12/54), respectively, and normal gastric mucosa tissues in where the positive expression rates of Shh,Gli1,MMP-2 and MMP-9 were 36.67%(11/30), 26.67%(8/30) , 30.00%(9/30), 33.33%(10/30), respectively. The expression of Shh, Gli1, MMP-2 and MMP-9 had no differences between gastric cancer adjacent tissues and normal gastric mucosa tissues (P>0.05). The expression of Shh, Gli1, MMP-2 and MMP-9 was not correlated with the sex, age, tumour's position in gastric cancer (P>0.05), but it was significantly correlated with differentiation level, depth invasion and lymphonode metastasis in gastric cancer (P<0.05). The expression of Shh and Gli1 was positively correlated with MMP-2, MMP-9, respectively.(2) When Hedgehog signaling pathway was blocked,the capacities of invasion and migration of SGC-7901 cells could be significantly inhibited (P<0.05), and there was lower expression of MMP-2 and MMP-9 about mRNA and protein in SGC-7901 cells at the same time(P<0.05).Conclusion:(1)It was confirmed by immunohistochemistry that Hedgehog signaling pathway participated in occurrence and progression of gastric cancer and was correlated with higher expression of MMP-2 and MMP-9 protein. Hedgehog signaling pathway may play an important role in the invasion and metastasis of gastric cancer by upregulating MMP-2 and MMP-9 protein. The combined detection of Shh, Gli1 and MMP-9 in gastric cancer tissues may be used as objective references for prognosis of gastric cancer.(2)After Hedgehog signaling pathway was blocked with cyclopamine specifically, the mRNA and protein expression level of MMP-2 and MMP-9 remarkably decreased. It was confirmed that Hedgehog signaling pathway may control rhe invasion and migration of SGC-7901 cells by regulating the expression of MMP-2 and MMP-9. Hedgehog signaling pathway may promote maligant phenotype of human gastric cancer cells by extracelluar matrix degradation, which lay a solid foundation for biotherapy research of targeting Hedgehog signaling pathway.