Overexpression of serine/threonine-protein kinase-1 in pancreatic cancer tissue: Serine/threonine-protein kinase-1 knockdown increases the chemosensitivity of pancreatic cancer cells.

Serine/threonine-protein kinase-1 (SMG-1) belongs to the phosphatidylinositol 3‑kinase‑related kinase family. Altered expression of SMG-1 contributes to human carcinogenesis and cancer progression. The present study detected the expression levels of SMG-1 in normal and cancerous pancreatic tissues and then assessed the effects of SMG-1-knockdown in pancreatic cancer cell lines in vitro. A pancreatic cancer tissue array and pancreatic cancer cell lines were used to detect the expression levels of SMG-1 and a lentivirus expressing either SMG-1 or negative control short hairpin (sh)RNA were used to knock down the expression of SMG-1 in the pancreatic cancer cell lines. Western blot, cell proliferation, Cell Counting kit-8, Transwell tumor cell migration and invasion assays, and flow cytometric analysis of cell apoptosis with or without gemcitabine or cisplatin treatment were performed to assess the tumor cells. The protein expression of SMG-1 was higher in the pancreatic cancer tissues and cells compared with the normal tissues. sh-SMG-1 lentivirus infection significantly suppressed the expression of SMG-1 in the pancreatic cancer cell lines, resulting in the inhibition of tumor cell proliferation and increased chemosensitivity to treatment with gemcitabine and cisplatin. However, SMG-1 knockdown had no effect on pancreatic cancer cell migration or invasion capacities. The protein expression of SMG-1 was increased in the pancreatic cancer tissues and was associated with an advanced tumor stage. Knock down of the expression of SMG-1 inhibited tumor cell proliferation and induced the chemosensitivity of pancreatic cancer cells in vitro.