Unknown,Transcriptomics,Genomics,Proteomics

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Sunitinib treatment exacerbates intratumoral heterogeneity in metastatic renal cancer (CGH)

ABSTRACT: The aim of this study was to investigate the effect of VEGF targeted therapy (sunitinib) on intratumoral heterogeneity (ITH) in metastatic clear cell renal cancer (mRCC). To explore ITH in detail, multiple tumor samples were taken from the primary renal tumors of mRCC patients who were sunitinib treated (n=23) or untreated (n=23). ITH of pathological grade, DNA (using array-based comparative genomic hybridisation), RNA (Illumina Beadarray) and protein (reverse phase protein array) were evaluated. Tumor grade heterogeneity was greater in treated compared to untreated tumors (P=0.002). Unsupervised and supervised analysis, for renal cancer driver, hypoxia and stromal gene signatures, was then performed. In untreated patient tumor samples, significant ITH occurred in chromosomal aberrations, RNA and protein expression, with clustering of DNA and RNA correlating for individual patients. In unsupervised analysis sunitinib therapy was not associated with increased ITH in DNA or RNA. However there was an increase in ITH for the driver mutation and hypoxia gene signatures (DNA and RNA) as well as increasing variability of protein expression with treatment (p<0.05). Despite this variability, significant chromosomal and RNA changes to targets of sunitinib, such as VHL, PBRM1 and CAIX, occurred in the treated samples. Together these findings suggest that sunitinib treatment has significant effects on the expression and ITH of key tumor and treatment specific genes. The results do not support the hypothesis that resistant clones are selected and predominate after initiation of targeted therapy; instead it appears that an initial clonal diversification occurs, supporting the hypothesis of polyclonal drug resistance. 128 samples from patients with clear cell renal cell carcinoma, including biological replicates of nephrectomy samples. Source of samples includes both biopsy and nephrectomy. DNA extracted from FFPE and fresh frozen tissue samples.

ORGANISM(S): Homo sapiens

SUBMITTER: Fiach O'Mahony

PROVIDER: E-GEOD-67818 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Purpose: To identify tissue microRNAs predictive of sunitinib activity in patients with metastatic renal-cell carcinoma (MRCC) and to validate them in a cellular model. Selected microRNAs were studied in serum from MRCC patients and healthy individuals. Methods: We screened 673 microRNAs using TaqMan Low-density Arrays (TLDAs) in tumors from MRCC patients with extreme phenotypes of marked efficacy and resistance to sunitinib, selected from an identification cohort (n=41). Differentially expressed microRNAs were selected using bioinformatics-based target prediction analysis and quantified by qRT-PCR in tumors from patients presenting similar phenoytpes selected from an independent cohort (n=117). Results were validated in a cellular model of sunitinib resistance and studied in serum from healthy individuals and MRCC patients. Results: TLDAs identified 64 microRNAs differentially expressed in the identification cohort. Seven candidates were quantified by qRT-PCR in the independent series. MiR-942 was the most accurate predictor of sunitinib efficacy (p=0.0074). High expression of miR-942, miR-133a, miR484, and miR-628-5p was significantly associated with decreased time-to-progression and overall survival. These microRNAs were overexpressed in the sunitinib resistant cell line Caki-2 in comparison with the sensitive parental cell line. Serum levels of miR-942, miR-133a, miR-484, miR-146a-5p, miR-374a and miR-486-5p were significantly reduced in MRCC patients compared to healthy controls. Conclusions: Our strategy identified differentially expressed microRNAs in MRCC patients presenting marked sensitivity and resistance to sunitinib. Mir-942 was the best predictor of efficacy. Results were confirmed in a cellular model of sunitinib resistance. We also identified exosome derived serum microRNAs differentially expressed in MRCC patients and healthy individuals. Taqman Low Density Array for 6 FFPE tissues obtained from extreme phenotype MRCC patients, (n=3 marked resistance to sunitinib treatment patients and n=3 marked sensitivity to sunitinib treatment patients), was performanced to screen 667 microRNAs.

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Sunitinib treatment exacerbates intratumoral heterogeneity in metastatic renal cancer (CGH)

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