Complement Component C3 and Complement Factor B Promote Growth of Cutaneous Squamous Cell Carcinoma.

Area of Science:

• Oncology
• Immunology
• Dermatology

Background:

• Cutaneous squamous cell carcinoma (cSCC) is a common metastatic skin cancer with rising incidence.
• The roles of complement system proteins, specifically C3 and complement factor B (CFB), in cSCC development are not fully understood.

Purpose of the Study:

• To investigate the expression and function of C3 and CFB in cutaneous squamous cell carcinoma.
• To evaluate C3 and CFB as potential biomarkers and therapeutic targets for cSCC.

Main Methods:

• Quantitative PCR and Western blotting were used to analyze C3 and CFB expression in cSCC cell lines and normal keratinocytes.
• Immunohistochemistry was performed on human cSCC tissues, actinic keratoses, and normal skin.
• Gene knockdown experiments and *in vivo* xenograft models were utilized to assess the functional impact of C3 and CFB.

Main Results:

• C3 and CFB expression were significantly upregulated in cSCC cells compared to normal keratinocytes.
• Higher C3 and CFB labeling was observed in invasive cSCCs and related subtypes compared to early-stage lesions and normal skin.
• Knockdown of C3 and CFB inhibited cSCC cell migration, proliferation, extracellular signal-regulated kinase 1/2 activation, and xenograft tumor growth.

Conclusions:

• C3 and CFB play crucial roles in the development and progression of cutaneous squamous cell carcinoma.
• C3 and CFB represent promising biomarkers and potential therapeutic targets for managing metastatic cSCC.