The Effect of 5% Imiquimod Cream on C57BL/6 Mouse Melanoma Growth

In, Seung Gyun; Lee, Jong Rok; Shin, Jeong Hyun; Choi, Gwang Seong

Abstract

BACKGOUND: Imiquimod enhances both acquired and innate immune responses by inducing the synthesis of IFN-alpha and other cytokines (TNF-alpha, IL-1, 6, 8, 12, GM-CSF). Imiguimod was investigated in relation to melanoma, a highly resistant cancer in its immunogenic nature, but also an attractive target for immunotherapy. OBJECTIVE: The purpose of this study was to investigate the anti-tumor effect of 5% imiquimod cream in vivo. METHOD: C57BL/6 mice were inoculated intradermally into the left flank with 2X103 murine B16 melanoma cells. Five groups (including vehicle only, imiquimod cream, imiquimod cream with dimethyl sulfoxide (DMSO), vehicle with ultrasound, and imiquimod cream with ultrasound) were treated once daily at the inoculation site of the melanoma cells. The tumor growth was evaluated daily by using a caliper. RESULTS: The difference in tumor growth was seen around day 12 of treatment, and only the group of 5% imiquimod cream with ultrasound showed a decrease in tumor growth when compared to the control group. CONCLUSION: These results indicate that topical application of 5% imiquimod cream on mouse skin melanomas induces inhibition of tumor growth, and imiquimod cream could be used for the combination treatment of malignant melanoma.