Biopolymeric nanogel delivery of doxorubicin induces apoptosis and inhibits growth of colon cancer cells through modulating Bax/Bcl2 ratio, AKT/PTEN, and activating Caspase-3.

BACKGROUND: Colorectal cancer (CRC) remains one of the leading causes of cancer-related deaths, underscoring the urgent need for improved therapeutic strategies that enhance efficacy while reducing systemic toxicity.

METHODS: This study presents the development of a novel folate receptor (FR)-targeted chitosan nanogel (FA-DOX-Ng) designed for targeted delivery of doxorubicin (DOX) to colorectal cancer cells. The nanogel was synthesized via ionic gelation to ensure controlled particle size and high drug loading capacity.

RESULTS: The synthesized FA-DOX-Ng exhibited a hydrodynamic diameter of 233 ± 32 nm, pH-responsive release behavior, and a loading efficiency of 43.2 ± 2.3 %. In vitro tests using HT-29 colorectal cancer cells revealed that FA-DOX-Ng markedly enhanced therapeutic effectiveness, leading to a 280-fold reduction in IC50 values (250 ng/mL for FA-DOX-Ng vs. 70 µg/mL for free DOX) and a therapeutic index of 4.0 (compared to 1.0 for free DOX). Real-time PCR analysis indicated upregulation of pro-apoptotic genes (PTEN, BAX, Caspase-8/9/3) and downregulation of anti-apoptotic genes (AKT, Bcl-2), confirming activation of the intrinsic apoptotic pathway. Flow cytometry analysis further demonstrated that FA-DOX-Ng induced apoptosis in 51.5 % of HT-29 cells, with minimal necrosis (2.2 %). Additionally, the nanogel showed high biocompatibility with normal HUVEC cells.

CONCLUSION: These results highlight FA-DOX-Ng as an innovative, FR-targeted drug delivery platform capable of enhancing the anticancer efficacy of DOX while minimizing systemic toxicity in colorectal cancer therapy.