T. Horiuchi1,2, H. Shiba1, Y. Shirai1,2, R. Iwase1,2, K. Haruki1, Y. Fujiwara1, K. Furukawa1, T. Uwagawa1, T. Ohashi2, K. Yanaga1 1The Jikei University School Of Medicine,Department Of Surgery,Tokyo, , Japan 2The Jikei University School Of Medicine,Department Of Gene Therapy, Research Center For Medical Science,Tokyo, , Japan
Introduction: ~Pancreatic cancer has a poor prognosis among visceral cancers, with an overall 5-year survival rate of around 5%. Currently, intravenous gemcitabine is a standard therapy for patient with advanced pancreatic cancer. Recently, gemcitabine plus nab-paclitaxel therapy was reported to be superior to gemcitabine alone in patients with advanced pancreatic cancer. However, the tumor resistance to chemotherapy is common and activation of nuclear factor-kappa B (NF-κB) is a key player in attenuation of anti-tumor effect of chemotherapy in pancreatic cancer. NF-κB is a transcription factor that plays an important role in the regulation of cell apoptosis, inflammation, and oncogenesis. Therefore, targeting downregulation of NF-κB activation is an important strategy to improve the efficacy of chemotherapy and outcome of patients with pancreatic cancer. We previously reported that nafamostat mesilate, a synthetic serine protease inhibitor, inhibited NF-κB activation and induced antitumor effects for pancreatic cancer. We hypothesized that nafamostat mesilate downregulates the activity of NF-κB and improves therapeutic outcome of pancreatic cancer. The purpose of this study is to prove that addition of nafamostat mesilate to gemcitabine and nab-paclitaxel enhances their antitumor effect against pancreatic cancer.
Methods: ~We assessed NF-κB activity and cell viability of human pancreatic cancer cell lines (PANC-1, MIA PaCa-2, ASPC-1) in the following five groups: ① those treated with gemcitabine alone, ② gemcitabine and nab-paclitaxel,
③ nafamostat mesilate alone, ④ triple combination (gemcitabine, nab-paclitaxel and nafamostat mesilate), or ⑤ vehicle as control. In combination groups, the cells were treated with gemcitabine and nab-paclitaxel at the same time. In triple combination group, the cells were incubated with nafamostat mesilate at 3 hours before chemotherapy. Activation of NF-κB was evaluated by measuring nuclear localization of p65 protein.
Results:~Cell viability was assessed by the MTT assay. Cell viability in triple combination group was lower than that in gemcitabine plus nab-paclitaxel group (PANC 1: p<0.001, MIA PaCa-2: p=0.004, ASPC-1: p<0.001). The nuclear extracts were assessed using ELISA. NF-κB activity in gemcitabine plus nab-paclitaxel group was higher than that in control group, and NF-kB activity was significantly surpressed in nafamostat mesilate group and in tiple combination group compared with control group and gemcitabine plus nab-paclitaxel group, respectively (PANC-1: p<0.001, MIAPaCa-2: p<0.001, ASPC-1: p<0.001).
Conclusion:~Nafamostat mesilate significantly inhibited NF-κB activation and enhanced anti-tumor effect of gemcitabine plus nab-paclitaxel against human pancreatic cancer.