Curcumin Inhibits UV Radiation–Induced Skin Cancer in SKH-1 Mice

Abstract

Objective As skin cancer incidence increases, research has focused on novel chemopreventive agents that inhibit tumor formation. In prior experimentation, curcumin, a naturally occurring food substance and anticarcinogenic agent, inhibited cutaneous squamous cell carcinoma xenograft growth. We hypothesize curcumin will inhibit UVB radiation–induced skin cancer growth in mice, approximating a human chemopreventive model. Study Design Randomized experimental animal and laboratory study. Setting Louisiana State University Health Sciences Center-Shreveport, Louisiana. Subjects and Methods SKH-1 mice were pretreated with oral or topical curcumin or oral or topical control (n = 11/group) for 14 days. Mice received UVB radiation 3 times weekly for 24 weeks or were not radiated. Number of tumors formed and time to tumor onset for each mouse were recorded through tumor harvest after week 24. Tumor multiplicity and time to tumor onset were compared. Results Time to tumor onset was significantly shorter in control mice compared to mice receiving either oral ( P = .025) or topical ( P = .015) curcumin. A significant difference in the average number of tumors formed per mouse was seen, as fewer tumors were formed in the oral curcumin ( P = .01) and topical curcumin ( P = .01) groups, compared with respective controls. No significant difference in average number of tumors per mouse was seen between oral and topical curcumin ( P = .56), suggesting that both routes were equally effective. Conclusion Curcumin appears to inhibit skin cancer formation and prolong time to tumor onset when administered by either an oral or topical route. These data suggest that curcumin may have chemopreventive potential against skin cancer, necessitating future experimentation with human subjects.