Effects of atorvastatin in combination with celecoxib and tipifarnib on proliferation and apoptosis in pancreatic cancer sphere-forming cells.

Cancer stem cell (CSC) plays an important role in pancreatic cancer pathogenesis and treatment failure. CSCs are characterized by their ability to form tumor spheres in serum-free medium and expression of CSC related markers. In the present study, we investigated the effect atorvastatin, celecoxib and tipifarnib in combination on proliferation and apoptosis in Panc-1 sphere-forming cells. The sphere-forming cells were isolated from Panc-1 cells by sphere-forming method. These sphere-forming cells showed CSC properties. The levels of CD44, CD133 and ALDH1A1 in the sphere-forming cells were increased. Moreover, Panc-1 sphere-forming cells were resistant to chemotherapeutic drug gemcitabine. Combined atorvastatin with celecoxib and tipifarnib synergistically decreased the sphere forming ability of Panc-1 cells and the drug combination also strongly inhibited cell proliferation and promoted apoptosis in the sphere-forming cells. The effects of the drug combination on the Panc-1 sphere-forming cells were associated with decreases in the levels of CD44, CD133 and ALDH1A1, and suppression of Akt and NF-κB activation. Results of the present study indicate that the combination of atorvastatin, celecoxib and tipifarnib may represent an effective approach for inhibiting pancreatic CSCs.

Synergistic anti-inflammatory effects of silibinin and thymol combination on LPS-induced RAW264.7 cells by inhibition of NF-κB and MAPK activation.

BACKGROUND: Combination drug therapy has become an effective strategy for inflammation control. The anti­inflammatory capacities of silibinin and thymol have each been investigated on its own, but little is known about the synergistic anti-inflammatory effects of these two compounds. PURPOSE: This study aims to investigate the synergistic anti-inflammatory effects of silibinin and thymol when administered in combination to lipopolysaccharide (LPS)-induced RAW264.7 cells. METHODS: RAW264.7 cells were pre-treated with silibinin and thymol individually or in combination for 2 h before LPS stimulation. Cell viability was detected by the MTT assay. Nitric oxide (NO) production was measured by Griess reagent. Reactive oxygen species (ROS) was evaluated by 2',7'-dichlorofluorescein-diacetate. ELISA was used to detect tumour necrosis factor-α (TNF-α), and interleukin-6 (IL-6). Western blot was performed to analyse the protein expression of LPS-induced RAW264.7 cells. RESULTS: We observed a synergistic anti-inflammatory effect of silibinin and thymol when administered in combination to LPS-induced RAW264.7 cells. Silibinin combined with thymol (40 µM and 120 µM respectively, with the molar ratio 1:3) had more potent effects on the inhibition of NO, TNF-α, and IL-6 than those exerted by individual administration of these compounds in LPS-induced RAW264.7 cells. The combination of silibinin and thymol (40 µM and 120 µM respectively, with the molar ratio 1:3) strongly inhibited ROS and cyclooxygenase-2 (COX-2). More importantly, the combination of silibinin and thymol (40 µM and 120 µM respectively, with the molar ratio 1:3) was also successful in inhibiting nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) activities. Our results suggest that the synergistic anti-inflammatory effects of silibinin with thymol were associated with the inhibition of NF-κB and MAPK signalling pathways. CONCLUSION: The combination of silibinin and thymol (40 µM and 120 µM, respectively, with the molar ratio 1:3) could inhibit inflammation by suppressing NF-κB and MAPK signalling pathways in LPS-induced RAW264.7 cells.