Prodrug polymeric micelles integrating cancer-associated fibroblasts deactivation and synergistic chemotherapy for gastric cancer

Background: The prognosis of patients with advanced gastric cancer (GC) remains unsatisfactory owing to distant metastasis and resistance to concurrent systemic therapy. Cancer-associated fibroblasts (CAFs), as essential participators in the tumor microenvironment (TME), play a vital role in tumor progression. Thus, CAFs-targeting therapy is appealing for remodeling TME and sensitizing GC to conventional systemic therapy. Methods: Amphiphilic SN38 prodrug polymeric micelles (PSN38) and encapsulated the hydrophobic esterase-responsive prodrug of Triptolide (TPL), triptolide-naphthalene sulfonamide (TPL-nsa), were synthesized to form PSN38@TPL-nsa nanoparticles. Then, CAFs were isolated from fresh GC tissues and immortalized. TPL at low dose concentration was used to investigate its effect on CAFs and CAFs-induced GC cells proliferation and migration. The synergistic mechanism and antitumor efficiency of SN38 and TPL co-delivery nanoparticle were investigated both in vitro and in vivo. Results: Fibroblast activation protein (FAP), a marker of CAFs, was highly expressed in GC tissues and indicated poorer prognosis. TPL significantly reduced CAFs activity and inhibited CAFs-induced proliferation, migration and chemotherapy resistance of GC cells. In addition, TPL sensitized GC cells to SN38 treatment through attenuated NF-kappa B activation in both CAFs and GC cells. PSN38@TPL-nsa treatment reduced the expression of collagen, FAP, and a-smooth muscle actin (alpha-SMA) in tumors. Potent inhibition of primary tumor growth and vigorous anti-metastasis effect were observed after systemic administration of PSN38@TPL-nsa to CAFs-rich peritoneal disseminated tumor and patient-derived xenograft (PDX) model of GC. Conclusion: TPL suppressed CAFs activity and CAFs-induced cell proliferation, migration and chemotherapy resistance to SN38 of GC. CAFs-targeted TPL and SN38 co-delivery nanoparticles exhibited potent efficacy of antitumor and reshaping TME, which was a promising strategy to treat advanced GC.