Tumor multifunctional targeting polymeric nanomicelles with polypharmacy payload for effective therapy and imaging of resistant renal cell carcinoma

Renal cell carcinoma (RCC) is very difficult to treat as the cells are mostly resistant to many current therapies. Therefore, newer treatments including better ways of drug delivery are urgently needed to fight this malignant disease efficiently. The ongoing work was done by generating and characterizing RCC cells that are resistant to everolimus, a front-line mTOR-targeted therapy, and tested whether a class of CARP-1 functional mimetic (CFM) compounds inhibits parental and everolimus-resistant RCCs in combination with sorafenib. CFMs inhibited RCC cell viability in a dose-dependent manner that was comparable to everolimus treatments as well as the combination with sorafenib. CFM-4.16 inhibited viabilities of everolimus-resistant RCC cells, albeit CFM-4.16 combined with sorafenib was more effective than CFM-4.16 alone. CFM-dependent loss of RCC cell viabilities was due in part to reduced cyclin B1 levels, activation of pro-apoptotic, stress-activated protein kinases (SAPKs), and apoptosis. However, CFMs and sorafenib are hydrophobic, and their dose escalation for in vivo studies remains challenging. We addressed the solubility and delivery concerns of CFM-4.16 and sorafenib by utilizing a nanotechnology-based approach. Our data thus far revealed that we have been successful in overcoming the solubility concerns of CFM-4.16 and sorafenib by encapsulating it in water-soluble vitamin E TPGS-based micellar nanoformulation that enables high drug loading and affords its intravenous administration for animal testing. We also use our polymeric NPs formulation for in vitro efficacy in parental, wild-type and everolimus-resistant RCC. After confirming the anticancer activity of CFM-4.16-loaded nanoformulations in vitro, we finally examined the intravenous (i.v.) administration of the CFM-4.16-loaded polymeric NPs in a clinically relevant RCC mouse model. The CFM-4.16 formulation inhibited the viability of parental and everolimus-resistant RCC cells in vitro and suppressed the growth of parental A498 RCC-cell-derived xenografts (RCC animal model), in part by stimulating apoptosis. After optimizing its potency and biologic stability, we performed imaging of animal inoculated with RCC tumor and PDX model by conjugation with NIR dye. The results showed high binding affinity and specific tumor uptake, faster normal tissue clearance and less non-target organ uptake. These findings make CFM-4.16 an important potential therapeutic in combination with sorafenib using nanoformulation in the treatment of RCCs. Citation Format: Hashem O. Alsaab, Samaresh Sau, Vino T. Cheriyan, Ulka Vaishampayan, Arun K. Rishi, Arun K. Iyer. Tumor multifunctional targeting polymeric nanomicelles with polypharmacy payload for effective therapy and imaging of resistant renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4107.