Regulatory Mechanisms of Keratinocyte Differentiation and Tumorigenesis

Keratinocytes are the predominant cell type of the epidermis, undergoing a tightly regulated programme of proliferation, stratification and terminal differentiation to form the protective barrier of the skin. This process is orchestrated by interlinked signalling pathways—including Notch, Wnt/β-catenin and NF-κB—that coordinate the expression and activity of key transcription factors such as interferon regulatory factor 6 (IRF6), Grainyhead-like 3 (GRHL3) and OVO-like 1 (OVOL1). Receptor-interacting protein kinase 4 (RIPK4) occupies a central node in this network, integrating upstream cues from protein kinase C to modulate downstream effectors that govern cytoskeletal remodelling, cell–cell adhesion and lipid barrier formation. Dysregulation of these regulatory axes can disrupt epithelial homeostasis, favouring loss of differentiation and the emergence of malignant keratinocyte clones. Depending on context, RIPK4 and associated factors may act either as tumour suppressors—by enforcing differentiation programmes—or as oncogenic drivers, by promoting epithelial–mesenchymal transition (EMT), invasion and aberrant proliferation. Improved understanding of these mechanisms has global significance for skin disease, wound repair and targeted cancer therapy.

Research from Nature Portfolio

Elevated RIPK4 expression has been shown to correlate with the progression of cervical squamous lesions to invasive carcinoma, highlighting its potential as both diagnostic and prognostic biomarker. In clinical specimens, RIPK4 levels rose sharply from low-grade intraepithelial lesions to full-blown carcinoma, and functional studies demonstrated that silencing RIPK4 reduced keratinocyte motility and invasion through downregulation of vimentin, matrix metalloproteinase 2 and fibronectin. These findings underscore a tumour-promoting role for RIPK4 in stratified epithelia and suggest that targeting this kinase may improve patient stratification and therapeutic outcome.

Regulatory Mechanisms of Keratinocyte Differentiation and Tumorigenesis publication trend

The graph below shows the total number of articles in regulatory mechanisms of keratinocyte differentiation and tumorigenesis across all publications each year (not limited to Nature Index journals).

Technical terms

Keratinocyte: A primary epidermal cell responsible for forming the skin’s protective barrier through a programme of proliferation and differentiation.

RIPK4 (Receptor-interacting protein kinase 4): A serine/threonine kinase that integrates signals from protein kinase C to regulate keratinocyte differentiation and, contextually, tumourigenesis.

Notch signalling: A cell–cell communication pathway that determines cell fate decisions, including initiation of keratinocyte differentiation.

EMT (Epithelial–mesenchymal transition): A process by which epithelial cells lose polarity and adhesion, acquiring migratory and invasive properties.

Transcription factor IRF6 (Interferon regulatory factor 6): A nuclear regulator essential for keratinocyte maturation and barrier formation, acting downstream of RIPK4.

References

1. The NOTCH-RIPK4-IRF6-ELOVL4 Axis Suppresses Squamous Cell Carcinoma. Cancers (2023).
2. Increased RIPK4 expression is associated with progression and poor prognosis in cervical squamous cell carcinoma patients. Scientific Reports (2015).
3. Insight Into the Function of RIPK4 in Keratinocyte Differentiation and Carcinogenesis. Frontiers in Oncology (2020).
4. Receptor-interacting Protein Kinase 4 and Interferon Regulatory Factor 6 Function as a Signaling Axis to Regulate Keratinocyte Differentiation*. Journal of Biological Chemistry (2014).