Proteomic analysis of human prostasomes

Prostasomes are organelles secreted by prostatic epithelial cells, and are believed to have a role in fertility and prostatic disease. They are known to influence sperm motility and the acrosome reaction, and are thought to have a role in cell transformation, immunosuppression, proliferation, facilitation of local invasion, and angiogenesis. Previously, we have demonstrated the inhibitory effect of prostasomes derived from human semen on angiogenesis using HUVEC cells grown on matrigel. In this study, we use the rat aortic ring assay system, arguably a closer reflection of the in vivo situation. Quantification was by a spectrophotometric method, and underlying mechanisms assessed. Prostasomes demonstrated a clear inhibition of angiogenesis, and this effect persisted after heat treatment of prostasomes to denature protein. This fits with other known effects of prostasomes known to be due to the membrane lipid component, which is unusually high in sphingomyelin and cholesterol.

Section: Introductionmentioning

confidence: 99%

Seminal prostasomes inhibit the angiogenesis activity of rat aortic rings

Delves

Goyal

Lwaleed³

et al. 2006

“…4 Proteomic analysis has shown prostasomes to contain upwards of 130 proteins, including tissue factor, complement inhibitors, and dipeptidyl peptidase IV which has shown to be involved in activation and deactivation of growth factors and cytokines. [5][6][7] The membrane characteristics of prostasomes are also unusual, being particularly rich in cholesterol and sphingomyelin. 8 Prostasome-like particles have also been shown to be produced by prostate cancer cells, both as cell lines in culture, 9 and by in situ prostate cancer, including metastatic deposits.…”

Section: Introductionmentioning

confidence: 99%

In vitro inhibition of angiogenesis by prostasomes

Delves

Stewart²,

Lwaleed

et al. 2005

Prostasomes are biologically active organelles that are secreted by human prostate epithelial cells, and it is believed that they have a role in prostatic disease. We studied the effect of prostasomes on the human umbilical vein endothelial cell (HUVEC)/Matrigel model of angiogenesis, and the association of labelled prostasomes with HUVECs. The growth inhibitory effect of prostasomes on HUVECs was assayed by spectrophotometric measurement of residual biomass. Preparations of HUVECs on a Matrigel base were exposed to prostasomes, and the development of capillary-like networks was quantified. Prostasomes were labelled with PKH-26, and cultured with HUVECs. Prostasomes were not shown to have a significant effect on HUVEC survival. Angiogenesis assays showed inhibition. The PKH-26-labelled particles were shown to have adhered to the HUVECs. This study adds the inhibition of an in vitro correlate of angiogenesis to the known actions of prostasomes.

“…26 They were enzymes Janus-faced nature of prostasomes G Ronquist and BO Nilsson (35%), transport/structural proteins (19%), GTP proteins (14%), chaperone proteins (6%), signal transduction proteins (17%) and novel proteins (9%). Some of these components have already been shown by other techniques to occur in the prostasomes.…”

Section: Biochemical Features Of Prostasomesmentioning

confidence: 99%

“…Gammaglutamyltransferase occurs in a very high concentration in human seminal plasma and most of it is bound to prostasomes. 26,41,42 Among the structural/transport proteins of prostasomes, six members of the annexin family were identified. 26 Annexins hold a central hydrophilic pore functioning as a Ca 2+ channel.…”

Section: Biochemical Features Of Prostasomesmentioning

confidence: 99%

See 1 more Smart Citation

The Janus-faced nature of prostasomes: their pluripotency favours the normal reproductive process and malignant prostate growth

Ronquist

Nilsson

2004

Prostasomes are submicron secretory granules synthesized, stored and secreted by the epithelial cells of the human prostate gland. They are membrane-surrounded also in their extracellular appearance and the membrane architecture is composite. They are believed to be life-giving and act as protectors of the spermatozoa in the lower and upper female genital tract on their way to the ovum. Hence, the prostasomes are immunosuppressive and inhibitory of complement activation. Further, they promote sperm's forward motility and have antioxidant and antibacterial capacities. The prostasomes with their many composite abilities seem to turn against the host cell after the age of 50 y being conducive to the transition of the normal prostate epithelial cell into a neoplastic cell and therewith lay the foundations of the very high prevalence of prostate cancer of men of more than 50 y of age. Prostate Cancer and Prostatic Diseases (2004) 7, 21-31. doi:10.1038/sj.pcan.4500684 Keywords: prostasomes Prostate cancerProstate cancer is the most common cancer in men in Europe, North America, and some parts of Africa. Incidence of prostate cancer is increasing steadily in most countries. Incidence and death rates differ according to race and geographical location. 1 Different autopsy studies performed in Western and Oriental populations have shown that the prevalence of prostate cancer is significantly higher than its incidence. Comparative assessments of these studies have provided similar prevalence rates in different races and geographical areas. 2 The differences in the incidence of prostate cancer in different races and geographical areas and the different progression of this incidence in populations of a race living in a foreign geographical area, strengthen the hypothesis that genetic and lifestyle factors are responsible for the difference in post-induction progression of prostate cancer. 3,4 The incidence rate of clinically apparent prostate cancer is eight-fold higher in the United States than in Japan, while the prevalence of latent prostate cancer, a presumed precursor of clinical prostate cancer, is similar in the two countries. 5 However, the initiating and promoting factors that determine the variability in the natural history of prostate cancer remain unknown. 6 There is a substantial discrepancy between the high incidence of prostate cancer and the extremely low incidence of primary cancer in the seminal vesicles, 7 although the two glands represent neighbouring anatomical locations, both of them being exocrine accessory genital glands and both being under similar hormonal control. Hence, there may be endogenous as well as exogenous factors promotive of prostate cancer development. We hypothesize that prostasomes with their exclusive origin in the prostate gland and with their Received