Identification of urinary candidate biomarkers of cisplatin-induced nephrotoxicity in patients with carcinoma

Nephrotoxicity limits the use of cisplatin (CP) in cancer therapy; however, current clinical measures of renal health do not reflect low degrees of kidney injury. Therefore, discovering new biomarkers for CP-induced acute kidney injury (AKI) is essential for monitoring kidney health during therapy. To identify novel candidate biomarkers in urine for reduced renal function due to CP therapy, we conducted a pilot study on cancer patients eligible for CP treatment. Urine from 30 patients was collected before (baseline) and after 3d of intravenous CP infusion. Urine samples were subjected to Isobaric Tag for Relative Absolute Quantitation (iTRAQ) analysis. Biological roles and pathways for the proteins with altered urine concentrations were identified using bioinformatic tools ITRAQ analysis detected 1411 proteins, 12 of which showed significantly altered levels. Growth differentiation factor-15 (GDF15), leucine-rich alpha-2-glycoprotein 1 (LRG1), and secreted phosphoprotein 1 (SPP1/ osteopontin, OPN) were identified as potential candidate markers by proteomic analysis and were validated by ELISA in another 30 patients and in a CP-induced AKI mouse model. Therefore, GDF15, LRG1, and SPP1 may be applied as novel candidate urinary markers of kidney injury after cisplatin treatment. These findings may facilitate the development of new methods to monitor kidney function, particularly in CP-based chemotherapy. Significance: Cisplatin is pivotal for cancer treatment; however, nephrotoxicity limits its use. Clinical measures for renal health are not reflective of early signs of acute kidney injury. Thus, new indicators of the state of renal health following cisplatin treatment will have to be discovered. This study reports the use of proteomics to mine for candidate markers of kidney injury in the urine of patients undergoing treatment with cisplatin. Results were experimentally validated using patient urine and a mouse model of cisplatin-induced acute kidney injury. The novel candidate biomarkers reported in this study may be used for the non-invasive monitoring of renal health and in mitigating the side-effects of cisplatin during the course of cancer treatment.