Prostate cancer is a main urological disease associated with significant morbidity and mortality. Radical prostatectomy and radiotherapy are potentially curative for localized prostate cancer, while androgen deprivation therapy is the initial systemic therapy for metastatic prostate disease. However, despite temporary response, most patients relapse and evolve into castration resistant cancer.Epithelial-mesenchymal transition (EMT) is a complex gradual process that occurs during embryonic development and/or tumor progression. During this process, cells lose their epithelial characteristics and acquire mesenchymal features. Increasing evidences indicate that EMT promotes prostate cancer metastatic progression and it is closely correlated with increased stemness and drug resistance.In this review, we discuss the main molecular events that directly or indirectly govern the EMT program in prostate cancer, in order to better define the role and the mechanisms underlying this process in prostate cancer progression and therapeutic resistance.

Prostate cancer is the second highest cause of cancer mortality after lung tumours. In USA it affects about 2.8 million men and the incidence increases with age in many countries. Therefore, early diagnosis is a very important step for patient clinical evaluation and for a selective and efficient therapy. The study of miRNAs' functions and molecular mechanisms has brought new knowledge in biological processes of cancer. In prostate cancer there is a deregulation of several miRNAs that may function as tumour suppressors or oncogenes. The aim of this review is to analyze the progress made to our understanding of the role of miRNA dysregulation in prostate cancer tumourigenesis.

In the recent years the importance of the role played by non-coding RNA on the regulation of gene expression was increased by numerous studies. The research mainly focused on small ncRNAs, such as miRNAs, while the functions of long non-coding RNA (lncRNA) have been much less studied. lncRNAs can be transcribed from intergenic, intragenic or specific chromosomal regions. Compared to miRNAs, lncRNAs have a complex secondary and tertiary structure which allows to bind proteins, RNA, DNA and to carry out their regulatory functions. Several studies showed that extracellular ncRNAs can circulate in the blood of both healthy and diseased patients. Most of the circulating ncRNAs are included in lipid or lipoprotein vesicles, such as apoptotic bodies, macrovesicles or exosomes, in which they are highly stable. The presence of circulating ncRNAs in the blood of cancer patients versus normal subjects suggested the possibility that these molecules may represent new diagnostic markers. HOTAIR is a HOX transcript antisense RNA, located in the HOXC locus, able to repress transcription in the posterior region of the HOXD locus. HOTAIR has been involved in the evolution of several primary tumors, wherein increase of HOTAIR expression has endorsed invasion and metastasis. In this review, we describe the experimental evidences on the potential role as circulating marker of lncRNA HOTAIR.

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The molecular mechanisms responsible for the metastatic progression of melanoma have not been fully defined yet. We have recently shown that an important role in this process is certainly played by HOX genes, whose regulation is under control of particular non-coding RNAs, some of which are present within the HOX locus. HOTAIR is the most studied among them, whose aberrant expression is associated with the metastatic progression of many malignancies. The aim of this study was to verify the role played by HOTAIR in metastatic progression of melanoma and to evaluate the circulating levels of HOTAIR in the blood of patients with metastatic melanoma. A series of melanocytic lesions were selected to evaluate the potential changes in the expression of HOTAIR during the evolution of the disease through in situ and molecular approaches. None of the benign melanocytic lesions showed the presence of HOTAIR. The staining of HOTAIR resulted very weak in the primary pT1 lesions, while it was very strong in all pairs of primary tissues and corresponding metastases. Surprisingly, we found the presence of HOTAIR in some intratumoral lymphocytes, while this positivity decreased in lymphocyte component further away from the tumor. HOTAIR was also detected in the serum of selected metastatic patients. These data allowed us to speculate on the fundamental role played by HOTAIR in tumor evolution of melanoma. Its presence in intratumoral lymphocytes might suggest that its involvement in the modulation of tumor microenvironment and the detection in the serum could be used in the management of melanoma patients.