Co-delivery of Plinabulin and Tirapazamine boosts anti-tumor efficacy by simultaneously destroying tumor blood vessels and killing tumor cells.

It is imperative to optimize chemotherapy for heightened anti-tumor therapeutic efficacy. Unrestrained tumor cell proliferation and sustained angiogenesis are pivotal for cancer progression. Plinabulin, a vascular disrupting agent, selectively destroys tumor blood vessels. Tirapazamine (TPZ), a hypoxia-activated prodrug, intensifies cytotoxicity in diminishing oxygen levels within tumor cells. Despite completing Phase III clinical trials, both agents exhibited modest treatment efficiency due to dose-limiting toxicity. In this study, we employed methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (mPEG-b-PDLLA) to co-deliver Plinabulin and TPZ to the tumor site, concurrently disrupting blood vessels and eliminating tumor cells, addressing both symptoms and the root cause of tumor progression. Plinabulin was converted into a prodrug with esterase response (PSM), and TPZ was synthesized into a hexyl chain-containing derivative (TPZHex) for effective co-delivery. PSM and TPZHex were co-encapsulated with mPEG-b-PDLLA, forming nanodrugs (PT-NPs). At the tumor site, PT-NPs responded to esterase overexpression, releasing Plinabulin, disrupting blood vessels, and causing nutritional and oxygen deficiency. TPZHex was activated in response to increased hypoxia, killing tumor cells. In treating 4T1 tumors, PT-NPs demonstrated enhanced therapeutic efficacy, achieving a 92.9 % tumor suppression rate and a 20 % cure rate. This research presented an innovative strategy to enhance synergistic efficacy and reduce toxicity in combination chemotherapy.