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Updated: Feb 27, 2026
Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
Published on: September 7, 2013
ADA-07 Suppresses Solar Ultraviolet-Induced Skin Carcinogenesis by Directly Inhibiting TOPK
Ge Gao1,2, Tianshun Zhang1, Qiushi Wang1
1The Hormel Institute, University of Minnesota, Austin, Minnesota.
Abstract:
Cumulative exposure to solar ultraviolet (SUV) irradiation is regarded as the major etiologic factor in the development of skin cancer. The activation of the MAPK cascades occurs rapidly and is vital in the regulation of SUV-induced cellular responses. The T-LAK cell-originated protein kinase (TOPK), an upstream activator of MAPKs, is heavily involved in inflammation, DNA damage, and tumor development. However, the chemopreventive and therapeutic effects of specific TOPK inhibitors in SUV-induced skin cancer have not yet been elucidated. In the current study, ADA-07, a novel TOPK inhibitor, was synthesized and characterized. Pull-down assay results, ATP competition, and in vitro kinase assay data revealed that ADA-07 interacted with TOPK at the ATP-binding pocket and inhibited its kinase activity. Western blot analysis showed that ADA-07 suppressed SUV-induced phosphorylation of ERK1/2, p38, and JNKs and subsequently inhibited AP-1 activity. Importantly, topical treatment with ADA-07 dramatically attenuated tumor incidence, multiplicity, and volume in SKH-1 hairless mice exposed to chronic SUV. Our findings suggest that ADA-07 is a promising chemopreventive or potential therapeutic agent against SUV-induced skin carcinogenesis that acts by specifically targeting TOPK. Mol Cancer Ther; 16(9); 1843-54. ©2017 AACR.
Insights
A new compound, ADA-07, effectively inhibits T-LAK cell-originated protein kinase (TOPK), a key player in skin cancer development. Topical application of ADA-07 significantly reduced skin tumor formation in mice exposed to solar ultraviolet irradiation.
Area of Science:
- Oncology
- Dermatology
- Molecular Biology
Background:
- Cumulative solar ultraviolet (SUV) irradiation is a primary cause of skin cancer.
- Mitogen-activated protein kinase (MAPK) cascades are crucial for SUV-induced cellular responses.
- T-LAK cell-originated protein kinase (TOPK) activates MAPKs and is implicated in inflammation, DNA damage, and tumor development.
Purpose of the Study:
- To investigate the chemopreventive and therapeutic potential of a novel TOPK inhibitor, ADA-07, against SUV-induced skin cancer.
- To elucidate the mechanism of action of ADA-07 in inhibiting TOPK activity and downstream signaling pathways.
Main Methods:
- Synthesis and characterization of the novel TOPK inhibitor ADA-07.
- Biochemical assays (pull-down, ATP competition, in vitro kinase assays) to confirm ADA-07's interaction with TOPK.
- Western blot analysis to assess the impact of ADA-07 on SUV-induced MAPK and AP-1 signaling.
- In vivo studies using SKH-1 hairless mice exposed to chronic SUV to evaluate the chemopreventive effects of topical ADA-07 treatment.
Main Results:
- ADA-07 specifically binds to the ATP-binding pocket of TOPK, inhibiting its kinase activity.
- ADA-07 suppressed SUV-induced phosphorylation of ERK1/2, p38, and JNK, leading to the inhibition of AP-1 activity.
- Topical application of ADA-07 significantly reduced skin tumor incidence, multiplicity, and volume in mice subjected to chronic SUV exposure.
Conclusions:
- ADA-07 is a potent and specific inhibitor of TOPK.
- ADA-07 demonstrates significant chemopreventive efficacy against SUV-induced skin carcinogenesis in a mouse model.
- ADA-07 represents a promising candidate for the chemoprevention or therapy of skin cancer.
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