Clusterin in the Male Reproductive Tract

Carlsson

et al. 2006

Intl Journal of Cancer

Prostate cancer consistently remains a difficult clinical enigma. Therefore, the development of novel strategies for diagnosis and treatment (e.g. immunotherapy) of prostate cancer is essential. We tried to identify the prostasome-derived proteins that were immunogenic in prostate cancer patients. Prostate cancer patients' sera (n 5 44) with high enzyme-linked immunosorbent assay (ELISA) titers against prostasomes were selected for immunoblotting against purified seminal prostasomes. The SDS-PAGE and immunoblotting experiments were performed with Bio-Rad systems. Twenty-five of the recognized proteins were isolated and analyzed by means of mass spectrometry. Out of 44 patients' sera, 31 (70%) demonstrated in immunoblotting experiments reactivity against several prostasomal protein bands in the molecular weight range of 10-200 kDa. Some of the bands (55, 70 and 170 kDa) were more frequently recognized by the patients' sera. Concomitantly run control sera generated only very weak or no bands at all. The most frequently occurring prostasomal proteins were identified as heat shock proteins (HSP 70, 71) and clusterin. This study identified the most important molecular targets of autoantibodies against prostasomes generated in connection with the development of prostate cancer in man. These immunogenic prostasomal proteins could be appropriate target molecules for specific immunotherapy of prostate cancer patients. ' 2006 Wiley-Liss, Inc.

Prostasome‐derived proteins capable of eliciting an immune response in prostate cancer patients

Carlsson

et al. 2006

Intl Journal of Cancer

Cell‐ and Region‐Specific Localization of Lysosomal and Secretory Proteins and Endocytic Receptors in Epithelial Cells of the Cauda Epididymitis and Vas Deferens of the Adult Rat

ANDONIAN,

HERMO

1999

Journal of Andrology

The epithelial cells lining the cauda epididymidis and vas deferens are active in endocytosis and have an abundance of lysosomes and a well‐characterized secretory apparatus. However, little is known about the nature of lysosomal proteins contained within lysosomes, the types of receptors on the cell surface, and the types of proteins secreted by these cells. In the present study, cathepsins A, D, B, and sulfated glycoprotein (SGP)‐1, well‐characterized lysosomal proteins, as well as SGP‐2, a secretory protein and lowdensity lipoprotein receptor–related protein‐2 (LRP‐2), an endocytic receptor, were immunolocalized at the light‐microscopic level within epithelial cells of the cauda epididymidis and vas deferens. Principal cells showed numerous intensely reactive lysosomes for cathepsins A, D, and SGP‐1 in all regions of the cauda and vas deferens and for cathepsin B only in the cauda epididymidis. Basal cells were intensely reactive for cathepsin A, unreactive for cathepsins D and B, and weakly reactive for SGP‐1 in the cauda region. In the vas deferens, these cells were intensely reactive for cathepsin A and SGP‐1 and unreactive for cathepsin B; in the case of cathepsin D, basal cells were weakly reactive in the proximal vas deferens but intensely reactive in the middle and distal vas deferens. Clear cells, present in the cauda region and proximal vas deferens, were intensely reactive for cathepsin A, weakly reactive for SGP‐1, and unreactive for cathepsins D and B, while narrow cells found mainly in the proximal vas deferens were intensely reactive for cathepsins A, D, and SGP‐1 and unreactive for cathepsin B. Thus, the expression of different lysosomal enzymes in the cauda epididymidis and vas deferens is not only cell‐ but also region‐specific, suggesting differences in the type of substrates internalized by these cells. SGP‐2, a secretory protein, showed a checkerboardlike staining pattern in the cytoplasm of principal cells of the cauda epididymidis, while the cytoplasm of all principal cells were intensely reactive in the vas deferens. This type of reaction, as well as staining of sperm, suggests that SGP‐2 is secreted into the lumen, where it functions in relation to sperm. The endocytic receptor LRP‐2 was noted only on the apical surface of principal cells of the cauda and vas deferens and in spherical structures indicative of endosomes suggestive of their role in the uptake of various ligands, including SGP‐2, for which it has a high binding affinity. Thus SGP‐2 in the cauda and vas deferens is not only secreted but endocytosed by principal cells, suggestive of an active turnover in the lumen. In summary, the epithelial cells of the cauda and vas deferens show marked differences in expression of lysosomal proteins, SGP‐2, and LRP‐2 suggestive of differences in their functional activity while sperm are stored and protected in these regions.

Circulating and Luminal Testicular Factors Affect LRP‐2 and Apo J Expression in the Epididymis Following Efferent Duct Ligation

HERMO,

XIAOHONG,

MORALES

2000

Journal of Andrology

Apolipoprotein J (clusterin or sulfated glycoprotein‐2) has been shown to be secreted by the epididymal principal cells, whereupon it binds to sperm in the lumen. Apolipoprotein J also is endocytosed by principal cells along the epididymis. Recently, it has been demonstrated that low‐density lipoprotein receptor—related protein‐2 (LRP‐2) mediates the endocytosis of Apo J and is present in the epididymis. The purpose of the present study was to determine the factors regulating the synthesis of these 2 proteins in various experimentally treated animals. The epididymides of adult rats were fixed with Bouin's fluid and examined with anti—Apo J and anti‐LRP‐2 antibodies by a light microscope immunocytochemical method. In normal adult animals, expression of Apo J was evident in principal cells of all epididymal regions except the proximal initial segment. Diffuse cytoplasmic staining indicated Apo J secretion. Reactive apical vesicles, presumably endosomal in nature, suggested endocytosis of Apo J. Lipoprotein receptor—related protein‐2 expression was solely apical in nature and was seen as an intense apical band in principal cells of all regions except the proximal and distal initial segment and distal caput regions of the epididymis. Hypophysectomy, up to 28 days after the procedure, did not affect expression of Apo J or LRP‐2 in principal cells along the entire epididymis. Orchidectomy, with or without testosterone replacement at all time intervals examined, also did not affect LRP‐2 expression along the entire epididymis. This also was noted for Apo J expression in all regions except the proximal initial segment. Thus, expression of these 2 proteins does not appear to be regulated by testicular or pituitary factors. In contrast, bilateral as well as unilateral (intact and ligated sides) efferent duct ligation resulted in dramatic differences in LRP‐2 and Apo J expression in principal cells in the various epididymal regions. In the case of LRP‐2, a complete absence of reaction was noted in principal cells along the entire epididymis. As for Apo J, expression in the distal initial segment, intermediate zone, and caput region remained unchanged compared with that in normal adult animals, whereas in the corpus and cauda epididymides, results of cytoplasmic staining were negligible. These results suggest that under conditions of efferent duct ligation, a circulating factor emanates from the testis to inhibit expression of LRP‐2 and Apo J in these epididymal regions. Furthermore, because Apo J was affected in a region‐specific manner, unlike the case for LRP‐2, different factors appear to be involved for each protein. These factors may be produced to inhibit proteins from being synthesized by the epididymis in the absence of luminal testicular input and may exist in cases of congenital and pathologic epididymal tubule blockages as well as after vasectomy. In the case of immunostaining for Apo J in the proximal initial segment only, normally unreactive principal cells in control adult animals became intensely reactive after orchidectomy as well as bilateral and unilateral (ligated side only) ligation. As this was not the case for hypophysectomized animals and the intact side of unilateral efferent duct—ligated animals, it is suggested that a testicular factor entering via the lumen of the efferent ducts serves to inhibit Apo J expression in this area. The present data also reveal that after efferent duct ligation, there are circulating factors that inhibit Apo J expression in a region‐specific manner (corpus and cauda) and that inhibit LRP‐2 expression along the entire epididymis and that these are derived from the testis. Furthermore, the data reveal that a testicular luminal factor appears to inhibit Apo J expression in the proximal initial segment of normal adult animals.