Pomalidomide promotes chemosensitization of pancreatic cancer by inhibition of NF-κB

Introduction: Nuclear factor κB (NF-κB) plays an important role in cancer progression and causes therapeutic resistance to chemotherapy. Pomalidomide, a third-generation immunomodulating drug derived from thalidomide, has been approved for uncontrolled multiple myeloma. We hypothesized that pomalidomide may inhibit the anticancer agent-induced NF-κB activity and enhance chemosensitization of combination chemotherapy with gemcitabine and S1 (Gem/S1) in pancreatic cancer. Methods: In vitro, we assessed NF-κB activity, induction of caspase cascade, cell apoptosis and cell proliferation using human pancreatic cancer cell lines (MIA PaCa- 2 and PANC-1). In vivo, we established an orthotopic xenograft mouse model for human pancreatic cancer by injection of PANC-1 cells. At 5 weeks after injection, the animals were randomly divided into four groups and treated with Gem (100 mg/kg) /S1 (10 mg/kg), with oral administration of pomalidomide (0.5 mg/kg), with combination of gemcitabine, S1, and pomalidomide or vehicle only. Results: Although chemotherapeutic agents induced NF-κB activation in pancreatic cancer cells, pomalidomide inhibited anticancer agent-induced NF-κB activation (p < 0.01). Of the four groups tested for the apoptosis-related caspase signals and apoptosis under both in vitro and in vivo conditions, Gem/S1/Pomalidomide group demonstrated the strongest activation of the caspase signals and proapoptotic effect. In Gem/S1/Pomalidomide group, cell proliferation and tumor growth were slower than those in other groups both in vitro and in vivo (p < 0.01). There were no obvious adverse effects except for thrombocytosis by using pomalidomide. Conclusions: Pomalidomide promotes chemosensitization of pancreatic cancer by inhibiting chemotherapeutic agents-induced NF-κB activation.