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Genetic analysis of Ras genes in epidermal development and tumorigenesis
Matthias Drosten1, Carmen G Lechuga1, Mariano Barbacid1
1Molecular Oncology Programme; Centro Nacional de Investigaciones Oncológicas (CNIO); Madrid, Spain.
Abstract:
Proliferation and differentiation of epidermal keratinocytes are tightly controlled to ensure proper development and homeostasis of the epidermis. The Ras family of small GTPases has emerged as a central node in the coordination of cell proliferation in the epidermis. Recent genetic evidence from mouse models has revealed that the intensity of Ras signaling modulates the proliferative capacity of epidermal keratinocytes. Interfering with Ras signaling either by combined elimination of the 3 Ras genes from the basal layer of the epidermis or by overexpression of dominant-negative Ras isoforms caused epidermal thinning due to hypoproliferation of keratinocytes. In contrast, overexpression of oncogenic Ras mutants in different epidermal cell layers led to hyperproliferative phenotypes including the development of papillomas and squamous cell carcinomas. Here, we discuss the value of loss- and gain-of-function studies in mouse models to assess the role of Ras signaling in the control of epidermal proliferation.
Insights
Ras signaling intensity controls epidermal keratinocyte proliferation. Mouse models show that altering Ras signaling, via gene elimination or overexpression, leads to epidermal thinning or hyperproliferation and tumors, respectively.
Area of Science:
- Dermatology
- Molecular Biology
- Oncology
Background:
- Epidermal homeostasis relies on controlled keratinocyte proliferation and differentiation.
- The Ras family of small GTPases plays a key role in coordinating epidermal cell proliferation.
Purpose of the Study:
- To investigate the role of Ras signaling intensity in regulating epidermal keratinocyte proliferation using mouse models.
- To assess the impact of both loss- and gain-of-function mutations in Ras signaling pathways on epidermal development and disease.
Main Methods:
- Utilized mouse models with genetic modifications to alter Ras signaling in epidermal keratinocytes.
- Examined effects of combined elimination of Ras genes (loss-of-function) and overexpression of dominant-negative or oncogenic Ras isoforms (gain-of-function).
Main Results:
- Loss-of-function studies (gene elimination) resulted in epidermal thinning due to keratinocyte hypoproliferation.
- Gain-of-function studies (oncogenic Ras mutants) induced hyperproliferative phenotypes, including papillomas and squamous cell carcinomas.
Conclusions:
- Ras signaling intensity is a critical determinant of epidermal keratinocyte proliferative capacity.
- Mouse models provide valuable insights into Ras signaling's role in epidermal homeostasis and tumorigenesis.
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