Extracellular Vesicles in Prostate Cancer: New Future Clinical Strategies?

Abstract

Prostate cancer (PCa) is the most common cancer—excluding skin tumors—in men older than 50 years of age. Over time, the ability to diagnose PCa has improved considerably, mainly due to the introduction of prostate-specific antigen (PSA) in the clinical routine. However, it is important to take into account that although PSA is a highly organ-specific marker, it is not cancer-specific. This shortcoming suggests the need to find new and more specific molecular markers. Several emerging PCa biomarkers have been evaluated or are being assessed for their potential use. There is increasing interest in the prospective use of extracellular vesicles as specific markers; it is well known that the content of vesicles is dependent on their cellular origin and is strongly related to the stimulus that triggers the release of the vesicles. Consequently, the identification of a disease-specific molecule (protein, lipid or RNA) associated with vesicles could facilitate their use as novel biological markers. The present review describes several in vitro studies that demonstrate the role of vesicles in PCa progression and several in vivo studies that highlight the potential use of vesicles as PCa biomarkers.

PSA and beyond: alternative prostate cancer biomarkers

“…Altered miRNA expression profiles have been associated with prostate cancer progression, aggressiveness, metastasis and recurrence, thereby highlighting the prognostic potential of miRNAs [83–86]. miRNAs have emerged as putative diagnostic and prognostic biomarkers that can distinguish tumor from normal tissues, aid in stratification of tumors and monitor treatment responses [83, 87]. Owing to their small size and resistance to endogenous RNase activity, miRNAs are stable biomarkers that can be readily detected in formalin-fixed tissues [88], as also in body fluids such as serum, plasma and urine [89].…”

“…Exosomes are small extracellular vesicles (30–100 nm in size) [96] that are gaining significant interest as alternative disease biomarkers that can be detected non-invasively in blood, urine or semen [87]. Exosomes are a promising source of protein and RNA/miRNA biomarkers for the early diagnosis and prognosis of prostate cancer [97].…”

Extracellular Vesicle-Mediated Reversal of Paclitaxel Resistance in Prostate Cancer

“…The difference is based on size and origin within the cell. 2 Only exosomes and MVs are of importance for the cell communication discussed within this paper. Exosomes are 40–100 nm in diameter and originate from inward budding of endosomal membranes, which causes the accumulation of intraluminal vesicles.…”

“…1 The prostate is an exocrine gland in the male reproductive system that contributes about 50–70% of the semen volume. 2 The prostate is composed of luminal and basal epithelial cells surrounded by stroma. 3 Both of these cell types may become cancerous.…”

“…2 However, PSA screening does not differentiate between benign or malignant PCa due to the test’s poor specificity. Localized PCa is typically managed with surgery or radiation therapy options.…”