A. R. Glover1, J. Zhao1, J. Ip1, J. Lee1, B. Robinson1, A. Gill1, P. Soon1, S. Sidhu1 1Kolling Institute Of Medical Research, Royal North Shore Hospital,University Of Sydney,Sydney, NSW, Australia
Introduction:
Adrenocortical carcinoma (ACC) is an aggressive malignancy with limited treatment options and high rates of recurrence following surgical resection. Long noncoding RNAs (lncRNAs) regulate multiple cell processes and have been implicated in the pathogenesis of adrenocortical carcinoma by exome sequencing and SNP analysis. The aim of this study was to identify lncRNAs associated with ACC outcomes using dedicated lncRNA microarrays of adrenocortical tumours.
Methods:
RNA was extracted from freshly frozen tissue with confirmation of diagnosis by histopathology. Focused lncRNA transcriptome analysis was performed using the ArrayStar Human LncRNA V3.0 microarray to identify differentially expressed lncRNAs between ACC and normal adrenal cortex (NAC). Selected lncRNAs were validated by qRT-PCR. To identify possible lncRNAs associated with recurrence, median expression levels of differentially expressed lncRNAs were compared using the Mann-Whitney test between those with a clinical history of recurrence and non-recurrence. From this analysis, lncRNAs were tested by qRT-PCR on an extended sample group to test this association with recurrence. Area under the receiver operating characteristic curves (AUC) was used to determine accuracy for clinical outcomes.
Results: Microarray of 16 samples (10 ACC, 6 NAC) showed distinct patterns of lncRNA expression with 956 lncRNAs differentially expressed (Corrected P<0.05). Of these 956 lncRNAs, 59 differentially expressed lncRNAs were found to be associated with ACC recurrence. These 59 lncRNAs, included carcinogenesis implicated lncRNAs such as GAS5, FEZF1-AS1, RPL23AP82, GNAS-AS1, MALAT-1 and PRINS. These carcinogenesis lncRNAs were tested by qRT-PCR on an extended group (20 ACCs) where PRINS was confirmed to be differentially expressed between recurrence and non-recurrence groups (P<0.05). Area under the receiver operating characteristic curve showed lower expression levels of PRINS was associated with recurrence (AUC=0.889, P=0.0044) and with metastatic disease on presentation (AUC=0.843, P=0.026).
Conclusions:
PRINS (psoriasis associated RNA induced by stress) has been implicated as a tumour suppressor in prostate cancer and may play a similar role in ACC. As expression levels of PRINS were found to be lower in samples associated with recurrence and the presence of metastatic disease at presentation it offers a novel prognostic and therapeutic target for further functional study.