B7-H4 Immune Checkpoint Protein Affects Viability and Targeted Therapy of Renal Cancer Cells

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Advanced renal cancer treatment often combines targeted therapy with immune checkpoint inhibitors.
• Therapeutic resistance and lack of response are significant challenges in current treatment protocols.
• Alternative immunotherapies targeting immune checkpoints may benefit specific patient populations.

Purpose of the Study:

• To investigate the expression of B7 immune checkpoint family members in renal cancer cells after targeted drug treatment.
• To identify potential actionable targets for overcoming resistance in advanced renal cancer.

Main Methods:

• Analysis of B7 family gene expression (PD-L1, PD-L2, B7-H2, B7-H3, B7-H4, B7-H5, B7-H6, B7-H7) in human renal cancer cell lines (Caki-1, A-498, 786-O).
• Treatment of cell lines with tyrosine kinase inhibitors (Axitinib, Cabozantinib, Lenvatinib) and mTOR inhibitors (Everolimus, Temsirolimus).
• Gene expression analysis using quantitative PCR and RNA interference (RNAi) with small interfering RNA (siRNA) to knock down B7-H4 expression.

Main Results:

• Differential expression patterns of B7 family members were observed in renal cancer cell lines following targeted drug treatments.
• B7-H4 gene expression was significantly upregulated in Caki-1 and 786-O cells after treatment with various targeted drugs.
• Knockdown of B7-H4 expression using siRNA led to decreased renal cancer cell viability and enhanced sensitivity to drugs.

Conclusions:

• B7-H4 expression is induced by targeted therapy in renal cancer cells.
• B7-H4 represents a potential actionable immune checkpoint target for combination therapy.
• Targeting B7-H4 may offer a therapeutic strategy for advanced renal cancer resistant to current treatments.