Grafting of Resveratrol-Chitosan Nanoparticles as a Promising Radiosensitizer and Protector in DMBA-Induced Breast Cancer in Mice.

Introduction: Breast cancer is the most common malignancy among women and the second leading cause of cancer-related deaths worldwide. Resveratrol, a polyphenolic stilbene derivative found in grapes, red wine, and other plants, possesses anti-cancer properties. Various studies have reported the potential of different nanomaterials to act as radiosensitizers against tumor cells. This study aimed to evaluate the antitumor and radiosensitizing effects of Resveratrol-Chitosan Nanoparticles (Res-Ch-NPs) in a DMBA-induced breast cancer mouse model.

Methods: Res-Ch-NPs were developed using the chitosan emulsification cross-linking technique. The particle size, entrapment efficiency, zeta potential, UV and FT-IR spectra, and drug release profile of Res-Ch-NPs were evaluated. The IC50 of Res-Ch-NPs, both individually and in combination with γ-irradiation, was calculated against the MCF-7 cell line using the MTT assay. The LD50 of Res-Ch-NPs was estimated, and 1/20 LD50 was used to assess the antitumor and radiosensitizing effects on breast cancer cell-bearing mice. The in vivo efficacy was evaluated in DMBA-induced breast cancer mice, examining tumor weight, volume, blood parameters (Hb%, RBCs, and WBCs), oxidative stress markers (MDA, GSH, SOD, and CAT), immune markers (INF-γ, TGF-β1, CD4, and CD8), and gene expression levels (p53, survivin, and STAT3). Additionally, histopathological examination of breast tissues was also carried out.

Results: Res-Ch-NPs demonstrated high entrapment efficiency (82.46 ± 1.02), a polydispersity index (0.65 ± 0.03), and a particle size of 184.60 ± 17.36 nm with a zeta potential of -46.78 ± 0.57 mV. The UV spectra of resveratrol and Res-Ch-NPs showed strong absorption at 230 and 250 nm. FTIR analysis confirmed the chemical stability of resveratrol in Res-Ch-NPs. The maximum release of Res-Ch-NPs was recorded at 55.07% after 44 hours. The IC50 values of Res-Ch-NPs, both individually and combined with γ-irradiation, against MCF-7 cell viability were 38.26 and 24.8 ± 0.76 μg/mL, respectively. The LD50 of Res-Ch-NPs was found to be 2090 mg/kg body weight. Treatment of DMBA-injected mice with Res-Ch-NPs and γ-irradiation significantly reduced tumor weight and volume, improved blood Hb%, RBC, and WBC levels, as well as breast MDA, GSH, SOD, and CAT levels. Additionally, breast levels of INF-γ, TGF-β1, CD4, and CD8 were reduced in DMBAinjected mice treated with Res-Ch-NPs and γ-irradiation. Conversely, the combination treatment upregulated p53 in breast cells and downregulated the expression of survivin and STAT3 genes.

Discussion: The findings confirmed that Res-Ch-NPs enhanced radiosensitivity, facilitating tumor regression and immune restoration. The modulation of pro-inflammatory and antioxidant pathways suggests a dual therapeutic role, acting as both a radiation enhancer and a tumor-suppressing agent. However, further research is needed to optimize nanoparticle dosing, assess long-term safety, and facilitate clinical translation into human studies.

Conclusion: Resveratrol-grafted chitosan shows promise as a radiosensitizer for cancer treatment by enhancing the responsiveness of tumor cells to γ-irradiation through the modulation of proinflammatory and antioxidant markers. Understanding the interactions between p53, survivin, and STAT3 is crucial for developing effective breast cancer treatments. Targeting survivin and modulating STAT3 activity may offer potential for future anticancer therapies.