Suppressive function of RKTG on chemical carcinogen-induced skin carcinogenesis in mouse

Area of Science:

• Molecular Biology
• Cell Signaling
• Oncology

Background:

• Raf kinase trapping to Golgi (RKTG) is a newly identified negative regulator of the Ras-Raf-MEK-ERK pathway.
• RKTG sequesters Raf-1 to the Golgi apparatus, modulating signaling.
• The physiological roles of RKTG in mitogenesis and carcinogenesis remain largely uncharacterized.

Purpose of the Study:

• To investigate the role of RKTG in skin carcinogenesis.
• To determine the impact of RKTG deficiency on chemical carcinogen-induced tumorigenesis.
• To elucidate the molecular mechanisms underlying RKTG's function in skin cancer.

Main Methods:

• Utilized RKTG-deficient (RKTG(-/-)) mice and wild-type littermates.
• Administered acute and two-stage chemical carcinogen treatments (DMBA/TPA) to mouse skin.
• Analyzed epidermis hyperplasia, proliferation, papilloma formation, tumor latency, regression, and levels of Raf-1 and ERK phosphorylation.

Main Results:

• RKTG(-/-) mice exhibited increased epidermis hyperplasia and proliferation after DMBA/TPA treatment.
• Papilloma number and size were significantly increased in RKTG(-/-) mice, with shortened tumor latency.
• Elevated Raf-1 and ERK phosphorylation were observed in RKTG-deficient keratinocytes and skin tumors, alongside prolonged tumor regression.

Conclusions:

• RKTG acts as a suppressive factor in chemical carcinogen-induced skin carcinogenesis.
• RKTG deficiency promotes tumor initiation and progression by enhancing keratinocyte proliferation and signaling.
• Disruption of RKTG function leads to increased mitogenic signaling and impaired tumor regression in mouse skin.