Calcineurin inhibitors modulate CXCR3 splice variant expression and mediate renal cancer progression

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Calcineurin inhibitors (CNI) are immunosuppressants used to prevent transplant rejection and treat inflammatory conditions.
• The role of CNI in cancer development and recurrence is not fully understood.
• Chemokine receptor CXCR3 and its splice variants (CXCR3-A and CXCR3-B) are implicated in tumorigenesis, with opposing functions.

Purpose of the Study:

• To investigate the impact of CNI on the expression and function of CXCR3 splice variants in renal cancer.
• To elucidate the mechanisms by which CNI may influence renal cancer progression.

Main Methods:

• Analysis of CXCR3 splice variant expression in human renal cancer tissues and cell lines.
• Treatment of renal cancer cells and normal renal cells with CNI to assess effects on CXCR3 expression and cell proliferation/migration.
• In vivo studies using human renal tumors in mice treated with CNI.

Main Results:

• Human renal cancer tissues and cell lines exhibit higher CXCR3-A and lower CXCR3-B expression compared to normal tissues.
• CNI treatment significantly downregulates CXCR3-B expression in renal cancer cells, while CXCR3-A remains unaffected.
• CNI-induced decrease in CXCR3-B correlates with increased renal cancer cell proliferation and migration, potentially via CXCR3-A and G(i) protein signaling.
• CNI administration promotes human renal tumor growth in vivo, accompanied by reduced CXCR3-B expression.

Conclusions:

• CNI may promote renal cancer progression by downregulating the tumor-suppressive CXCR3-B variant and enhancing pro-proliferative signals, possibly through CXCR3-A.
• Targeting CXCR3 splice variants or their downstream signaling pathways could offer a therapeutic strategy to prevent CNI-associated renal cancer progression.