Theoretically, on account of improved local bioavailability of photosensitizers and attenuated systemic phototoxicity, intravesical instillation-based photodynamic therapy (PDT) for bladder cancer (BCa) would demonstrate significant advantages in comparison with the intravenous route. Actually, the low transmucosal efficiency, hypoxia regulation deficiency, as well as the biosafety risks of intravesical drug agents all have greatly limited the clinical development of instillation-based PDT for BCa. Herein, based on our recent findings on bladder intravesical vectors and photodynamic treatment, we explore and find that the conventional antiparasitic agent nitazoxanide (NTZ) by mixing with chlorine e6 (Ce6) conjugated human serum albumin (HSA), HSA-Ce6, is capable of forming self-assembled HSA-Ce6/NTZ nanoparticles (NPs). Then, the HSA-Ce6/NTZ complexes further fabricate with fluorinated chitosan (FCS), the synthesized transmucosal carrier, to form a biocompatible nanoscale system HSA-Ce6/NTZ/FCS NPs, which exhibit remarkably improved transmucosal delivery and uptake capacities compared with HSA-Ce6/NTZ alone or non-fluorinated HSA-Ce6/NTZ/CS NPs. Meanwhile, due to the metabolic regulation of tumor cells by NTZ, the tumor hypoxia could be efficaciously ameliorated to further favor PDT. This work represents a new photosensitizer nanomedicine formulation for the perfection of PDT performance through the modulation of tumor hypoxia by clinically approved agents. Thus, intravesical instillation of HSA-Ce6/NTZ/FCS NPs with favorable biocompatibility, followed by cystoscope-mediated PDT, could achieve a dramatically improved therapeutic effect to ablate orthotopic bladder tumors.
Keywords: bladder cancer; fluorinated chitosan; instillation-based photodynamic therapy; nitazoxanide; transmucosal delivery.