Ski acts as therapeutic target of qingyihuaji formula in the treatment of SW1990 pancreatic cancer.

Background: Qingyihuaji formula (QYHJ) is a widely used herbal formula that has shown promising antitumor effect in the treatment of pancreatic cancer in the Cancer Hospital, Fudan University, Shanghai, China.

Objective: This research was conducted to study whether Ski acts as a therapeutic target of QYHJ formula in the treatment of SW1990 pancreatic cancer.

Methods: The expression changes of Ski mRNA and protein in SW1990 pancreatic cancer subcutaneously transplanted tumor treated with QYHJ were detected by real-time polymerase chain reaction and Western blot. Then, we established a stable transfection SW1990 cell with low expression of Ski through lentivirus-mediated RNA interference (RNAi) technique. The responses to QYHJ treatment on a subcutaneously transplanted tumor with different Ski expression statuses were evaluated. Finally, the effect of Ski downregulation on SW1990 cell biological behavior was also evaluated.

Results: Expression of Ski mRNA and protein in SW1990 subcutaneously transplanted tumor decreased dramatically after the treatment with QYHJ. Stable transfection cells with low expression of Ski (SW1990/Ski RNAi) were created, and negative vector-transfected cells (SW1990/con RNAi) were used as controls. The tumor weight inhibitory rates of QYHJ on subcutaneously transplanted tumors formed by SW1990 or SW1990/con RNAi were 29.6% and 32.2%, respectively, whereas they were 16.0% to 17.8% when the tumors were formed by SW1990/Ski RNAi. Ski downregulation sensitized the response of SW1990 cells to TGF-beta1-induced growth inhibition in vitro. Flow cytometric analyses revealed that the percentage of cells in the G1 phase increased from 40.4% to 62.9% when Ski was downregulated. The subcutaneously transplanted tumors formed by SW1990/Ski RNAi grew much more slowly than those formed by parental and control vector-transfected cells.

Conclusion: Ski acts as therapeutic target of QYHJ in the treatment of SW1990 pancreatic cancer cells, and its expression status mediates different responses to QYHJ treatment.