Temperature-sensitive nanogels combined with polyphosphate and cisplatin for the enhancement of tumor artery embolization by coagulation activation

Transcatheter arterial chemoembolization (TACE) is the first-line therapy for hepatocellular carcinoma (HCC). However, the exacerbated hypoxia microenvironment induces tumor relapse and metastasis post-TACE. Here, temperature-sensitive block polymer complexed with polyphosphate-cisplatin (Pt-P@PND) was prepared for the enhancement of tumor artery embolization by coagulation activation. After supra-selective infusion into the tumor vessels, Pt-P@PND nanogels performed efficient embolization of tumor arteries by sol-gel transition at body temperature. Meanwhile, coagulation cascade was evoked to form blood clots in the peripheral arteries inaccessible to the nanogels by released PolyP. The blood-clots-filled hydrogel networks composed of gel and clots showed a denser structure and higher modulus, thereby achieving long-term embolization of all levels of tumor arteries. Pt-P@PND nanogels efficiently inhibited tumor growth and reduced the expression of HIF-1α, VEGF, CD31, and MMP-9 on VX2 tumor-bearing rabbit model. The released nitro-Pt stimulated the immunogenic cell death of tumor cells, thus enhancing the antitumor immune response to suppress tumor relapse and metastasis post-TACE. It is hoped that Pt-P@PND nanogels can be developed as a promising embolic agent with procoagulant activity for enhancing the antitumor immune response through a combination of embolism, coagulation, and chemotherapy. STATEMENT OF SIGNIFICANCE: : Clinical embolic agents, such as Lipiodol and polyvinyl alcohol (PVA) microspheres, are limited by their rapid elimination or larger size, thus lead to incomplete embolization of trans-catheter arterial chemoembolization (TACE). Herein, temperature-sensitive Pt-P@PND nanogels were developed to achieve long-term embolization of all levels of tumor arteries by gel/clot generation. The released Pt induced immunogenic cell death in tumor cells, which improved the antitumor immune microenvironment by the maturation of DCs and lymphocytic infiltration. Pt-P@PND nanogels successfully inhibited tumor growth and activated an antitumor immune response to curb the recurrence and metastasis of residual tumor cells both in a VX2 tumor-bearing rabbit model and in a 4T1 tumor-bearing mouse model; these findings suggest that Pt-P@PND could be developed as an ideal embolic agent for clinical TACE treatment.