Imiquimod attenuates the growth of UVB-induced SCC in mice through Th1/Th17 cells

Maki Yokogawa, Mikiro Takaishi, Kimiko Nakajima, Reiko Kamijima, John Digiovanni, Shigetoshi Sano
Molecular Carcinogenesis 2013, 52 (10): 760-9
Imiquimod (IMQ), a Toll-like receptor (TLR) 7/8 agonist, has been used to treat various skin neoplasms, including genital warts, actinic keratoses, and superficial basal cell carcinomas. Although IMQ has been recognized to activate both innate and adaptive immunity, the underlying mechanism(s) by which IMQ exerts its anti-tumor activity in vivo remains largely unknown. In this study, we took advantage of skin cancer-prone mice to characterize the effects of IMQ on ultraviolet irradiation (UV)-induced de novo carcinogenesis. Transgenic mice with keratinocytes expressing constitutively activated Stat3 (K5.Stat3C mice) developed squamous cell carcinomas (SCC in situ) as early as after 14 wk of UVB irradiation, while wild-type mice required much higher doses of UVB with more than 25 wk of UVB irradiation to produce SCC. Topical treatment of K5.Stat3C mice with IMQ attenuated UVB-induced epidermal dysplasia (SCC in situ). In addition, SCC growth due to increased total irradiation doses was significantly attenuated by IMQ treatment. Topical IMQ treatment induced T cell and plasmacytoid dendritic cell infiltrates at the tumor sites, where levels of IL-12/23p40, IL-12p35, IL-23p19, IL-17A, and IFN-γ mRNAs were up-regulated. Immunohistochemistry revealed T cell infiltrates consisting of T1, Th17, and CD8(+) T cells. We speculate that topical IMQ treatment attenuates the de novo growth of UVB-induced SCC through activation of Th17/Th1 cells and cytotoxic T lymphocytes.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"