Dual role of Curcumin and nano-formulations in radiotherapy: sensitizing cancer cells and protecting normal cells.

INTRODUCTION: Curcumin, the principal bioactive constituent of turmeric, demonstrates a bifunctional role in radiotherapy by enhancing the radiosensitivity of malignant cells while concurrently conferring protection to normal cells. Nevertheless, its clinical application is hindered by limited bioavailability. This investigation assesses the effectiveness of two innovative nano-formulations-namely nanomicelles and nanoniosomes-in augmenting curcumin's radiosensitizing and radioprotective properties.

METHODS AND RESULTS: Human colorectal carcinoma (HT-29) cells and human foreskin fibroblasts (HFF) were treated with bulk curcumin, nanomicelles, or nanoniosomes, followed by exposure to 6 MV X-ray radiation. Cellular viability, apoptotic induction, and clonogenic survival were evaluated through MTT assays, annexin V-propidium iodide staining, and colony formation assays, respectively. All curcumin formulations decreased cancer cell viability, with nanomicelles exhibiting a notably lower IC50 (20 µM) compared to nanoniosomes (135 µM) in HT-29 cells. Nanomicelles demonstrated dual functionality by sensitizing HT-29 cells to radiation-evidenced by a 40% reduction in survival fraction at 2 Gy (p < 0.01)-and protecting HFF cells from radiation-induced apoptosis, reducing apoptotic rates by 30% relative to controls. Conversely, nanoniosomes displayed cytotoxic effects without significant radioprotective activity.

CONCLUSION: The findings indicate that nanomicelle-based curcumin formulations possess both radiosensitizing and radioprotective capabilities, whereas nanoniosomes exhibit cytotoxicity without conferring radioprotection.