Smad3 Sensitizes HCC Cells To The Effects Of Cisplatin By Repressing The Phosphorylation Of AKT Pathway

Objective:To investigate the role of smad3 to the chemosensitivity of cisplatin in HCC.Methods:Smad3 was upregulated and downregulated in HCC cells; CCK-8 assay, plate clony formation assay, apoptosis assay, xenograft tumor formation assay, IHC assay were performed to detect chemosensitivity of HCC cells to cisplatin in vitro and in vivo; Western blot assay was performed to measure the expression of target gene of smad3.Results:smad3-overexpression cells 7721-smad3 and smad3-deficiency cells LM3-shsmad3 were established; smad3-overexpression cells were sensitive to cisplatin compared with parallel smad3-deficiency cells; smad3 upregulated p21Cipl and downregulated c-myc, cyclinD 1, bcl2 with the treatment of cisplatin.Conclusion:smad3 sensitizes HCC cells to cisplatin by upregulation of p21Cipl and downregulation of c-myc, cyclinD 1, bcl2. This finding provides new evidence for biological stratification and individual treatment in HCC.Objective:To investigate the role of non-smad pathways in the chemosensitivity of HCC cells to cisplatin increased by smad3 overexpression.Methods:The interaction of smad3 and non-smad pathways were measured by western blot with the treatment of TGFβ1 and corresponding small molecule inhibitors; Non-smad signalings were also measured by western blot with the treatment of cisplatin; CCK-8 assay and plate clony formation assay were conducted to evaluate cell proliferation ability of HCC cells with the treatment of cisplatin and PI3K/AKT inhibitor LY294002; Western blot assay was performed to measure the expression of target gene of smad3 and to evaluate the role of smad3-deficiency in cisplatin resistance.Results:Smad3 increased the phosphorylation of ERK, JNK, p38 and inhibited the phosphorylation of AKT pathway. Smad3-deficiency cells were resistant of cisplatin by activating of AKT pathway in HCC. LY294002 obviously increased chemosensitivity of smad3-deficiency cells to cisplatin compared with their parental smad3-overexpression cells in HCC; LY294002 and cisplatin synergistically upregulated p21cipl and downregulated c-myc, cyclinDl, bcl2 in smad3-deficiency cells compared with smad3-overexpression cells.Conclusion:Smad3 sensitizes HCC cells to cisplatin by repressing the phosphorylation of AKT; LY294002 restores chemosensitivity of HCC to cisplatin in smad3-deficiency cells. These findings provide new evidences of combination of conventional chemotherapeutics and targeted drugs.