Parthenolide increases the sensitivity of gastric cancer cells to chemotherapy

To investigate the effect of parthenolide (PTL), a sesquiterpene lactone medicinal compound, on the sensitivity of the gastric cancer cell line SGC7901 and the DPP- and ADR-resistant sublines SGC7901/DDP and SGC7901/ADR to cisplatin [diamminedichloroplatinum (Ⅱ), DDP] and adriamycin (ADR) in vitro.

SGC7901, SGC7901/DDP, and SGC7901/ADR were treated with various concentrations of PTL alone or in combination with DDP or ADR. The effects on cell proliferation, apoptosis, and expression/activity of several proliferation/apoptosis-related proteins [B-cell lymphoma-2 (Bcl-2), cyclin D1, nuclear factor-kappa B (NF-κB), and Caspase-8] and drug transporters (P-glycoprotein and multidrug resistance protein-1) were measured using flow cytometry, Western blotting, and in vitro activity assays.

Treatment of SGC7901 cells with PTL inhibited cell growth, increased apoptosis, and sensitized the cells to DPP. Mechanistically, PTL treatment resulted in downregulation of NF-κB activity and Bcl-2 expression, and upregulation of Caspase-8 activity. Similarly, PTL co-treatment of SGC7901/DDP and SGC7901/ADR overcame their resistance to DDP and ADR, respectively, with concomitant inhibition of NF-κB, Bcl-2, Cyclin D1, P-glycoprotein, and multidrug resistance protein-1 expression and/or activity.

PTL treatment decreases drug resistance in SGC7901, SGC7901/DDP, and SGC7901/ADR cells, as reflected by induction of apoptosis, inhibition of proliferation, downregulation of pro-survival and drug resistance pathways, and upregulation of pro-apoptotic pathways. Our results suggest that co-treatment with PTL may thus complement existing therapies for gastric cancer.