Molecular profiles and urinary biomarkers of upper tract urothelial carcinomas associated with aristolochic acid exposure [mRNA]

This study presents a comprehensive multi-omic analysis of upper urinary tract urothelial tumours (UTUC) and urines of patients with past exposure to carcinogenic aristolochic acid (AA). We determined complex miRNA:mRNA tumor networks and their key protein components. Tumor exome and transcriptome sequencing revealed a burden of AA-specific mutations in UTUC and identified deleteriously mutated genes and their mRNA transcripts. A subset of identified urinary miRNAs presents potential biomarkers of UTUC development or presence. Recurrent upper urinary tract carcinomas (UTUC) arise in the context of nephropathy linked to exposure to the herbal carcinogen aristolochic acid (AA). We aimed to delineate the detailed biological programs underlying UTUC tumorigenesis in patients from endemic aristolochic acid nephropathy (AAN) regions in Southern Europe, by using an integrative multi-omics analysis of UTUCs, corresponding unaffected tissues and of patient urines. Quantitative miRNA and mRNA expression profiling, immunohistochemical analysis by tissue microarrays, and exome and transcriptome sequencing were performed in UTUC and non-tumor tissues. Urinary miRNAsof cases undergoing surgery were profiled before and after UTUC resection. RNA and protein levels were analyzed using appropriate statistical tests and trend assessment. Dedicated bioinformatic tools were used for analysis of pathways, mutational signatures and result visualization. The results delineate UTUC-specific miRNA:mRNA networks comprising 89 miRNAs associated with 1862 target mRNAs and involving deregulation of cell cycle, DNA damage response, DNA repair, bladder cancer, oncogenes, tumor suppressors, chromatin structure regulators and developmental signaling pathways. Key UTUC-specific transcriptome components were confirmed at the protein level. Exome and transcriptome sequencing of UTUC revealed AA-specific COSMIC mutational signature 22, with 68-76% AA-specific, deleterious mutations propagated at the mRNA level. We next identified a signature of UTUC-specific miRNAs consistently more abundant in the patients’ urine prior to tumor resection. The gene regulation programs of AAN-associated UTUC tumors are highly complex and involve regulatory miRNAs prospectively applicable to non-invasive urine-based screening of AAN patients for cancer recurrence. Gene expression profiles from UTUC tumors and matched normal urothelium of 12 patients with aristolochic acid nephropathy related cancers were determined by using the Affymetrix Human Genome U133 Plus 2.0 Arrays, matched with upstream regulatory miRNAs determined by Applied Biosystems TaqMan Low Density Arrays (TaqMan Array Human MicroRNA Panel A and B) on the ABI 7900HT Sequence Detection System (Applied Biosystems, CA, USA). Modulation of gene products (proteins) were validated by tissue microarray-based immunohistochemistry analysis. The study was complemented by exome and transcriptome sequencing of a UTUC subset, and a temporal screen of cell-free miRNAs in urine samples of 5 UTUC patients, collected before and after surgery.