A.B. Stewart

Current Drug Therapy for Prostate Cancer: An Overview

Prostate cancer is the most common cancer amongst men in the USA and the second most common malignant cause of male death worldwide after lung cancer. The life time risk of having microscopic evidence of prostate cancer for a 50 year old man is 42%. Prostate cancer is thus becoming an increasingly significant global health problem in terms of mortality, morbidity, as well as economically. This review, discusses current medical therapeutic options for prostate cancer including traditional treatments using luteinising hormone releasing analogues (LHRH), anti-androgens and estrogen treatments, and the use of novel drugs directed against molecular targets considered important in oncogenesis and metastasis. Prostate cancer chemoprevention using 5alpha-reductase inhibitors and the role of gene therapy are also considered.

In vitro inhibition of angiogenesis by prostasomes

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.

Prostasomes: a role in prostatic disease?

Prostasomes are membrane-bound secretory vesicles, in the nanometre diameter range, secreted by the prostatic ductal epithelium [1] into the lumen, where they form part of the ejaculate. Although known to have specific biological properties, their physiological role and overall significance remain far more debatable. There has been comparatively little written about these structures since their detection two decades ago, and this may help explain the relative lack of awareness of prostasomes within the urological community.

Antiprostasome antibodies are not an appropriate prognostic marker for prostate cancer

Objective. Antiprostasome antibodies (APAs) have been identified in serum of patients with prostate cancer and have been proposed as a new marker for metastatic disease. This study reassesses the role of APAs as a prognostic indicator for prostate cancer. Material and methods. Serum samples from healthy controls (n=7) and patients with prostate cancer (n=22) were assayed for APAs using an enzyme-linked immunosorbent assay. Results. APAs in varying amounts were present in healthy individuals as well as in men with prostate cancer. Higher levels were inversely and significantly associated with prostate-specific antigen (PSA). No significant relationships were noted between APA levels and other parameters such as age, time since diagnosis, metastatic status, Gleason histological score and hormonal treatment. Conclusions. The presence of serum APA is unlikely to be a strong prognostic indictor for prostate cancer on an individual basis as false positives will occur. However, such immune reactions which may be associated with PSA in cancer patients are in any case of interest in both the biology of prostate cancer and male fertility. The source of prostasomal antigen may be of critical importance to the outcome of the assay. However, immune reactions to prostasomes may be of considerable interest and warrant continued investigation.