Two major challenges facing cancer immunotherapy are the relatively low therapeutic efficacy and the potential side effects. New drug delivery system and efficient drug combination are required to overcome these challenges. We utilize an alginate hydrogel system to locally deliver 2 FDA-approved drugs, celecoxib and programmed death 1 (PD-1) monoclonal antibody (mAb), to treat tumor-bearing mice. In two cancer models, B16-F10 melanoma and 4T1 metastatic breast cancer, the alginate hydrogel delivery system significantly improves the antitumor activities of celecoxib (CXB), PD-1 mAb, or both combined. These effects are associated with the sustained high concentrations of the drugs in peripheral circulation and within tumor regions. Strikingly, the simultaneous dual local delivery of celecoxib and PD-1 from this hydrogel system synergistically enhanced the presence of CD4 C inteferon (IFN)-g C and CD8C IFN-g C T cells within the tumor as well as in the immune system. These effects are accompanied with reduced CD4 C FoxP3 C regulatory T cells (Tregs) and myeloid derived suppressor cells (MDSCs) in the tumor, reflecting a weakened immuosuppressive response. Furthermore, this combinatorial therapy increases the expression of two anti-angiogenic chemokines C-X-C motif ligand (CXCL) 9 and CXCL10, and suppresses the intratumoral production of interleukin (IL)-1, IL-6, and cycloxygenase-2 (COX2), suggesting a dampened pro-tumor angiogenic and inflammatory microenvironment. This alginate-hydrogel-mediated, combinatorial therapy of celecoxib and PD-1 mAb provides a potential valuable regimen for treating human cancer.

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Compelling evidence suggests that the epithelial-mesenchymal transition (EMT) correlates with aggressiveness of tumors and poor survival. FGF19 has been shown to be involved in EMT in cholangiocarcinoma and colorectal cancer, however, molecular mechanisms underlying FGF19-induced EMT process in hepatocellular carcinoma (HCC) remain largely unknown. Here, we show the expression of FGF19 is significantly elevated and negatively associated with the expression of E-cadherin in HCC tissues and cell lines. Ectopic FGF19 expression promotes EMT and invasion in epithelial-like HCC cells through repression of E-cadherin expression, whereas FGF19 knockdown enhances E-cadherin expression and hence diminishes EMT traits in mesenchymal-like HCC cells, suggesting FGF19 exerts its tumor progressing functions as an EMT inducer. Interestingly, depletion of FGF19 cannot abrogate EMT traits in the presence of GSK3β inhibitors. Furthermore, FGF19-induced EMT can be markedly attenuated when FGFR4 is knocked out. These observations clearly indicate that FGFR4/GSK3β/β-catenin axis may play a pivotal role in FGF19-induced EMT in HCC cells. As FGF19 and its specific receptor FGFR4 are frequently amplified in HCC cells, selective targeting this signaling node may lend insights into a potential effective therapeutic approach for blocking metastasis of HCC.