Therapeutic effect of topical application of curcumin during treatment of radiation burns in a mini-pig model.

Curcumin protects the skin against radiation-induced epidermal damage and prevents morphological changes induced by irradiation skin, thereby maintaining the epidermal thickness and cell density of basal layers. In this study, the effects of topical curcumin treatment on radiation burns were evaluated in a mini-pig model. Histological and clinical changes were observed five weeks after radiation exposure to the back (6°Co gamma-radiation, 50 Gy). Curcumin was applied topically to irradiated skin (200 mg/cm²) twice a day for 35 days. Curcumin application decreased the epithelial desquamation after irradiation. Additionally, when compared to the vehicle-treated group, the curcumin-treated group showed reduced expression of cyclooxygenase-2 and nuclear factor-kappaB. Furthermore, irradiation prolonged healing of biopsy wounds in the exposed area, whereas curcumin treatment stimulated wound healing. These results suggest that curcumin can improve epithelial cell survival and recovery in the skin and therefore be used to treat radiation burns.

Combined treatment with silibinin and epidermal growth factor receptor tyrosine kinase inhibitors overcomes drug resistance caused by T790M mutation.

Although epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) produce an initially dramatic response in lung cancer patients harboring a mutation in the EGFR gene, development of acquired resistance is almost inevitable. A secondary mutation of threonine 790 (T790M) is associated with approximately half of the cases of acquired resistance. This study investigated whether the addition of silibinin to therapy with gefitinib or erlotinib could overcome T790M-mediated drug resistance considering that silibinin has various antitumor effects, including EGFR modulation. Silibinin selectively reduced the activity of the EGFR family (EGFR, ErbB2, and ErbB3) through the inhibition of receptor dimerization in lung cancer cells with EGFR mutations, but not in those harboring the wild type. In primary and acquired resistant cells with T790M, addition of silibinin enhanced the ability of EGFR-TKIs to downregulate EGFR signals and to inhibit cell growth. Similarly, the combination of silibinin and erlotinib effectively suppressed tumor growth in erlotinib resistance-bearing PC-9 xenografts. The results indicate that the addition of silibinin to EGFR-TKIs is a promising strategy to overcome T790M-mediated drug resistance.