Macrophage inhibitory cytokine 1 plasma levels in testicular cancer patients during cisplatin combination treatment and their relation to endothelial damage.

Abstract

e15035 Background: Chemotherapy- (CTx) related endothelial damage contributes to cardiovascular morbidity in testicular cancer (TC) patients (pts). We used an unbiased translational approach to identify mechanisms of and potential biomarkers for this damage. Methods: During varying time periods human microvascular endothelial cells (HMEC-1) were in vitro exposed to bleomycin, cisplatin or left untreated. From 18k cDNA microarray expression signals were obtained, and quantified with an Affymetrix GMS428 scanner. Differences were analysed at single gene and pathway level, and validated by qRT-PCR. With ELISA, protein levels of 1 candidate biomarker were measured in TC pt plasma before, during and 1 month after bleomycin etoposide cisplatin CTx. Levels were related to endothelial damage plasma markers (von Willebrand Factor [vWF], high-sensitivity C-Reactive Protein [hs-CRP]). Results: Microarray data from 16k genes identified several genes with highly differential expression; Macrophage Inhibitory Cytokine 1(MIC-1), Activating Transcription Factor 3 (ATF3) and Amphiregulin (AREG) had strong differences in >1 experimental setting. We regarded these plausible candidates, and confirmed changes by qRT-PCR. Pathway analysis showed a strong association with ‘P53’ and ‘Diabetes Mellitus’ gene sets. Based on known function, we chose to validate MIC-1 protein levels in 41 TC pts. Pre-CTx MIC-1 levels did not differ from healthy controls (TC pts median 383 pg/mL [range 187-1935] vs 340 pg/mL [range 213-504], p=0.06). During CTx levels of MIC-1, vWF and hsCRP significantly increased. MIC-1 levels correlated with vWF and hsCRP at baseline (vWF rs= 0.35, P=0.03; hsCRP rs= 0.39, P=0.01), during (hsCRP at cycle 1d 8 rs= 0.44, P=0.01; vWF at cycle 3 d8 rs= 0.40, P=0.02) and after CTx (vWF rs= 0.56; P<0.01). Conclusions: An unbiased approach in a preclinical model revealed a set of genes related to bleomycin- and cisplatin-induced endothelial activation, such as MIC-1. The increases in plasma levels and the association with vWF and hsCRP suggest that MIC-1 may be a biomarker for CTx-related endothelial damage. Supported by Dutch Cancer Society grant 2009-4365.