Data di Pubblicazione:
2016
Citazione:
NON-CODING RNAS IN HIGH-GRADE SEROUS EPITHELIAL OVARIAN CANCER / P. Todeschini ; tutor: M. Samaja ; co-tutor: A. Ravaggi ; coordinatore: M. Clerici. Università degli Studi di Milano, 2016 Jul 01. 28. ciclo, Anno Accademico 2015. [10.13130/todeschini-paola_phd2016-07-01].
Abstract:
Abstract
Introduction: High-grade serous ovarian carcinoma (HGSOC) is the most lethal gynecologic malignancy, mainly because the disease is frequently diagnosed at an advanced stage and is characterized by the early onset of chemoresistant recurrences. The lack of reliable diagnostic and prognostic markers, together with the lack of effective therapies, are the major obstacles to the clinical management of patients with HGSOC. A new class of non-coding RNAs (ncRNAs), such as microRNA (miRNAs) and long non-coding RNAs (LncRNAs), with a function of gene expression regulation, have been discovered to play an important role in human cancers. Increasing evidences suggest that ncRNAs are involved in cancer progression and development of chemoresistance, and support their role as potential diagnostic, predictive and prognostic biomarkers. The hypoxic condition within the tumor microenvironment, improving the tumor neovascularization, represents an essential event contributing to the development of a more aggressive HGSOC phenotype. Recently, a group of miRNAs, termed hypoxia regulated-miRNAs (HRMs), have been identified as key elements in response to hypoxia, regulating important mechanisms involved in tumor progression. The complexity of hypoxia molecular mechanisms has not been fully elucidated yet in HGSOC, therefore there is an urgent need to discover novel biomarkers clinically useful to select patients with hypoxic tumor, that may benefit of tailored treatments.
Aims of the study: My PhD project aims at elucidating transcriptional and post-transcriptional signatures characterizing HGSOC, both at the serum and tissue levels. In detail, the research effort includes: i) the investigation of circulating miRNAs as novel potential biomarkers for HGSOC detection; ii) the analysis of mRNA, miRNA and lncRNA expression profiles of HGSOC and normal tissues; iii) the evaluation of hypoxia-regulated miRNA expression in HGSOC and normal tissues.
Methods: Sera from 168 HGSOC stage III-IV patients and 65 healthy donors were gathered together from two independent collections and stratified into a training set, for miRNA marker identification, and a validation set, for data validation. Nine synthetic viral/C.Elegans spike-in oligos were added to serum samples before RNA extraction, to allow accurate normalization. miRNA expression profiles were obtained using Agilent Microarray Technologies®. An innovative statistical approach for microarray data normalization, based on the contribute of spike-in oligos and the most invariant miRNAs, was developed to identify, in the training set, differentially expressed miRNAs. Signature validation in both the training and validation sets was performed by Real Time quantitative PCR (RT-qPCR) and confirmed by droplet digital PCR (ddPCR).
A total of 99 tumor biopsies were collected from HGSOC stage III-IV patients, partially matched with the serum sample cohort (n=76). Thirty normal tissues were obtained from normal ovary (HOSE) and luminal fallopian tube surface epithelia, both representing the normal counterpart for HGSOC, whose histogenesis is still a matter of debate. Gene and miRNA expression profiles were obtained using Agilent Microarray Technologies®. miRNA expression levels were correlated with patient outcomes, as overall survival (OS) and progression-free survival (PFS). Additionally, a subgroup of 14 chemo-resistant and 14 chemo-sensitive HGSOC patients, together with 10 normal tissues were deep sequenced for the discovery of novel HGSOC specific coding and non-coding transcripts.
Results: A panel of 97 miRNAs emerged significantly differentially expressed (92 up-regulated and five down-regulated) between sera of HGSOC patients and healthy donors by microarray analysis. Among them, the following
Tipologia IRIS:
Tesi di dottorato
Keywords:
non-coding RNA; ovarian cancer; circulating microRNA; hypoxia
Elenco autori:
P. Todeschini
Link alla scheda completa:
Link al Full Text: