Prostasomes: extracellular vesicles from the prostate

Abstract

The term 'prostasomes' is generally used to classify the extracellular vesicles (EVs) released into prostatic fluid by prostate epithelial cells. However, other epithelia within the male reproductive tract also release EVs that mix with 'true' prostasomes during semen emission or ejaculation. Prostasomes have been proposed to regulate the timing of sperm cell capacitation and induction of the acrosome reaction, as well as to stimulate sperm motility where all three are prerequisite processes for spermatozoa to attain fertilising capacity. Other proposed functions of prostasomes include interfering with the destruction of spermatozoa by immune cells within the female reproductive tract. On the other hand, it is unclear whether the distinct presumed functions are performed collectively by a single type of prostasome or by separate distinct sub-populations of EVs. Moreover, the exact molecular mechanisms through which prostasomes exert their functions have not been fully resolved. Besides their physiological functions, prostasomes produced by prostate tumour cells have been suggested to support prostate cancer spread development, and prostasomes in peripheral blood plasma may prove to be valuable biomarkers for prostate cancer.

Exosomes in semen: opportunities as a new tool in prostate cancer diagnosis

“…Prostasomes molecular composition could reflect their capacity to influence PCa growth and metastasis. Proteomic profile of prostasome isolated from SF identify prostatespecific membrane proteins (like TMPRSS2), prostatespecific transglutaminase, and prostate stem cell antigen (PSCA), confirmed the prostatic origin of these vesicles (16,37,38). The first efforts to identify the prostasomes in a PCa patient's blood was the detection of anti-prostasome antibodies (39)(40)(41).…”

“…These vesicles are spherical nanoparticles with a diameter of 50 to 500 nm, released by prostatic epithelial cells in the extracellular media. These vesicles, described for the first time in 1982, promote motility of sperm cells (35); regulate sperm cell capacitation, acrosome reaction, and immune suppression within the female reproductive tract (16,36). Prostasomes molecular composition could reflect their capacity to influence PCa growth and metastasis.…”

Exosomal microRNAs in liquid biopsies: future biomarkers for prostate cancer

“…In prostasomes term, there are several populations: one with a small size type equivalent to exosomes, and released by prostate cells because of multivesicular endosomes with the plasma membrane, and other type equivalent to microvesicles with large size and derived by direct shedding of plasma membrane [43].…”

Prostasomes as a source of diagnostic biomarkers for prostate cancer

“…Transformed PCa cells lose cell polarity, increasing the release of PSA into blood; thus, high blood PSA titers may be indicative of PCa. However, only 25%-40% of men with elevated PSA levels are actually diagnosed with PCa after prostate biopsy (8,9), and although high PSA levels may indicate small, localized, and low-grade malignant tumors, they may also result from benign prostatic hyperplasia (10). Furthermore, PSA levels may rise as a consequence of prostatitis or urinary tract infection and are highly variable between healthy individuals (11)(12)(13).…”