Anisamide-conjugated PLGA nanoparticles for targeted co-delivery of sorafenib and paclitaxel in colorectal cancer.

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Background: Colorectal cancer continues to be one of the leading cancers, ranking third in occurrence and second in cancer-associated fatalities worldwide. Additionally, its therapy is limited by drug solubility, systemic toxicity and resistance. The high rates of incidence, death and treatment challenges emphasize the critical need, for improved therapeutic approaches. Sorafenib (SOR), a multi-targeted kinase inhibitor inducing apoptosis and ferroptosis, and paclitaxel (PTX), a microtubule-stabilizing agent, are mechanistically complementary but limited by poor bioavailability. Sigma-1 receptor (σ1R), overexpressed on CRC cells, offers a targetable entry point via anisamide (AA), a benzamide ligand. This study developed AA-conjugated PLGA nanoparticles co-loaded with SOR and PTX as targeted CRC nanotherapy. Methods: AA was conjugated to Pluronic F-127 via DCC condensation, confirmed by FTIR and ¹H NMR. SOR+PTX AA-PLGA NPs were fabricated by nanoprecipitation and optimized using Box-Behnken Design. The formulation was optimized and assessed for characteristics in-vitro uptake, cytotoxic effects, and apoptosis in HCT116, HT29, and CT26 cells. In vivo antitumor efficacy, pharmacokinetics, hemocompatibility, and organ toxicity were assessed. Results: After optimization, the SOR+PTX-AA-PLGA nanoparticles displayed a size of 192.21±7.55 nm, a PDI of 0.252±0.065, and drug loading (%) of 8.87±1.03 (SOR) and 8.43±1.44 (PTX). The drugs were released slowly in two phases and followed Korsmeyer-Peppas law of drug release. Targeted nanoparticles exhibited 2.0-2.7 fold higher cytotoxic activity compared to free drug combinations. Significant decreases in IC ₅₀ value were evidenced in all the three colorectal cancer cell lines with HT29 at 1.81 µg/mL, HCT116 at 1.41 µg/mL, and CT26 at 1.62 µg/mL. The apoptotic index radically increased up to 1.44 (HT29), 1.28 (HCT116), and 1.38 (CT26), the maximum values, in all the groups. In vivo SOR+PTX AA, PLGA nanoparticles resulted in a tumor size of 6.51 fold smaller than the control and was even more effective than free SOR (1.22 fold) and PTX (1.50 fold). Pharmacokinetic analysis demonstrated that the AUC was increased by 2.31 times, and the half life was extended by 4.5 times compared to free drugs, pointing to greater drug persistence in the body. At the same time, no alterations were detected in the liver/kidney function markers (ALT, AST, BUN, creatinine; P>0.05) of the treated groups, and only trace levels of hemolysis were observed, which are indications of safety. Conclusions: Anisamide targeted PLGA nanoparticles markedly enhanced co, delivery, cellular uptake, cytotoxicity, and apoptosis, which were reflected in better tumor suppression and longer systemic exposure. This delivery system has great potential for targeted colorectal cancer therapy.