Synergistic delivery of 5-FU and thymoquinone via biogenic CaCO3 NPs in hyperglycemia-linked colorectal cancer cell.

AIM: This study evaluated two novel combination therapies using 5-Fluorouracil (5-FU), Thymoquinone (TQ), and cockle shell - derived calcium carbonate nanoparticles (CaCO3 NPs) against HT-29 colorectal cancer (CRC) cells under hyperglycemic conditions.

METHODS

5-FU and TQ were successfully encapsulated into CaCO3 NPs through encapsulation at various drug-to-nanoparticle ratios. Physicochemical characterization was performed to confirm the morphology, and particle stability. Drug release studies assessed pH-responsive behavior, while biocompatibility was evaluated on NIH/3T3 cells. Cytotoxicity and cell cycle analyses were conducted on HT-29 cells under glycemic and hyperglycemic conditions.

RESULTS

High encapsulation efficiency was achieved at a 1:5 drug-to-nanoparticle ratio while maintaining the aragonite structure and stable physicochemical properties. The nanoformulations exhibited pH-sensitive drug release with enhanced release at acidic pH (4.8), simulating the tumor microenvironment. Improved biocompatibility and reduced toxicity were observed in normal NIH/3T3 cells compared to free drugs. Both 5-FU:TQ-CaCO3 NPs and 5-FU-CaCO3 NPs:TQ combinations significantly inhibited HT-29 proliferation and induced G1 cell cycle arrest, especially under hyperglycemic conditions. Combination index analysis confirmed synergistic effects of both treatments.

CONCLUSION

The findings suggest the potential therapeutic efficacy of 5-FU:TQ-CaCO3 NPs and 5-FU-CaCO3 NPs:TQ in treating CRC associated with hyperglycemia and demonstrate the capability of biogenic CaCO3 NPs to effectively deliver chemotherapeutic agents of different polarity with minimal toxicity.