| Background:Gastric cancer is a highly malignant carcinoma.It has a poor prognosis due to luck of effective drugs.The Hedgehog pathway,especially the Gli1,act an important role in gastric oncogensis.And,Gli1 also regulates the drug-resistance of several tumor types.Meanwhile,FA2 H,a hydroxylase of fatty acids,was identified also associated with drug-resistance in recent research.Therefore,study on whether a potential crosstalk between FA2 H and Gli1 and FA2 H promoting a possible clinical treatment strategy for this lethal disease is needed.Aims:To investigate the association between the expression of Gli1 and FA2 H in gastric cancer.Observe the result reverse the drug resistance in vitro and vivo by elevating FA2 H or adding exogenous 2’R.Furthermore,to explore the potential mechanism how FA2 H regulates the expression of Gli1.Methods:Cell lines of Sgc7901 and Mkn45,and 20 paired gastric cancer specimens were chosen for this research.Western blotting,Immunohistochemistry and Real-time PCR were used to determine the expression level of related proteins and mRNAs in these cell lines.Transwell assay,MTT assay and wound healing assay were used for assessment of cell proliferation or migration.Xenografts in nude mice were performed to evaluate the effect of FA2 H in vivo.Results:In 20 paired gastric and para-cancer tissues,we found a positive correlation between FA2 H and Gli1 in human gastric cancer tissues.In addition,overexpression or knockdown of FA2 H can regulate mTOR-Gli1 which was a SMO-independent pathway and exert influence on sensitivity of gastric cancer cell lines to cisplatin in vitro and vivo.After adding 2′-hydroxylated fatty acid 2′R,we conformed the similar trend of increasing level of FA2 H.To simulate clinical therapy in gastric cancer,we attempt various combination of mTOR inhibitor rapamycin,Gli1 inhibitor Gant61,and 2′R.Interestingly,the effect of triplet combination of rapamycin,Gant61 and 2′R is not superior to dyad group 2′R included.Moreover,compared with 2′R treatment alone,combination of rapamycin and Gant61 had the similar effect on improving sensitivity of gastric cancer cells to cisplatin.Conclusions: Elevating FA2 H or adding exogenous 2′R can block mTOR-Gli1 pathway to increase sensitivity to cisplatin in gastric cancer.Therefore,adding 2′R to replace target agents against mTOR or Gli1,or combined with other gene inhibitors may be a potential therapy strategy to reverse drug-resistance. |
