PCPH expression is an early event in the development of testicular germ cell tumors

Abstract

Abstract. Testicular germ cell tumors (TGCTs) include various malignancies with distinct pathologies that share a common precursor lesion (intratubular germ cell neoplasia, unclassified, ITGCNU, or carcinoma in situ, CIS). TGCTs, as a whole, represent a highly curable tumor paradigm, with high sensitivity to radiotherapy and, especially, to cisplatinbased chemotherapy. However, a percentage of cases display therapeutic resistance, and the molecular mechanisms underlying such resistant phenotype remain to be elucidated. We put forward the notion that expression of oncogenic forms of the PCPH gene, which are known to confer resistance to radiation and chemotherapeutic drugs, including cisplatin, may be expressed in TGCTs, and thus contribute to the development of therapeutic resistance. To begin testing this concept, we studied PCPH expression in human TGCT cell lines and in 54 solid tumors by RT-PCR, Western immunoblot and immunohistochemistry. The results demonstrated that: i) PCPH is expressed in TGCT cell lines and tumors, including CIS; ii) its expression levels vary among different TGCT pathologies, being generally higher in well differentiated regions and lower in areas of predominant proliferation; iii) PCPH expression is substantially increased in tumors relative to matched normal testicular tissue; iv) tumor samples express PCPH polypeptides of low molecular mass, consistent with the known size of the PCPH oncoprotein, that are either absent from, or markedly reduced in, matched normal tissue.Collectively, these results positively identify PCPH as a good early molecular marker for testicular neoplasms, and strongly indicate that immunodetection of truncated PCPH polypeptides may be a useful diagnostic tool for TGCT.

PCPH/ENTPD5 Expression Enhances the Invasiveness of Human Prostate Cancer Cells by a Protein Kinase Cδ–Dependent Mechanism

“…Alterations in PCPH expression detected in rat mammary tumors (16) and in tumor cell lines of diverse tissue origin (17) were consistent with aberrations of either PCPH transcript splicing or posttranslational processing of the PCPH protein, resulting in loss of the normal PCPH protein and the presence of aberrant PCPH polypeptides. Analyses of human laryngeal, breast, and testicular tumors and tumor cell lines yielded similar results (18)(19)(20). We now report results from experiments to evaluate the PCPH expression in human prostate cancers, its possible participation in initiation and/or malignant progression, and its involvement in determining the malignant phenotype of prostate cancer cells.…”

“…PCPH has previously been associated with malignant development on the basis of its activity as an oncogene (4,5), its aberrant expression in animal and human tumors (16)(17)(18)(19)(20), and its antiapoptotic activity (8,15). However, the involvement of PCPH in the regulation of tumor cell invasiveness has not been reported to date.…”

“…The rabbit polyclonal anti-PCPH antiserum, produced by BioSynthesis, Inc., was previously described (18)(19)(20). Sections of normal human tissues (larynx, testes, skin, liver) that express PCPH (6,9,18) were used as positive controls.…”

“…Methods for preparation of total cellular extracts in the presence of a protease inhibitors cocktail, SDS-PAGE electrophoresis of cellular proteins (50 Ag), and transfer onto polyvinylidene difluoride membranes were as previously described (15,18,20). Membranes were incubated with anti-PCPH, anti-PKCy, or anti-GAPDH; washed with Tween 20 in PBS; incubated with peroxidase-conjugated secondary antibody; and the signal was then detected with a chemiluminescence-based system (Pierce).…”

Distribution of NTPDase5 and NTPDase6 and the regulation of P2Y receptor signalling in the rat cochlea

“…They are localised to the endoplasmic reticulum and Golgi apparatus respectively, and may be involved in glycosylation reactions [18,22]. NTPDase5, also known as proto-carcinogenic progression of hamster embryo cells (PCPH) [23], is present in normal and tumour samples from rat and human tissue [24,25], but the evidence for release of soluble forms is currently limited to in vitro studies. NTPDase5 and NTPDase6 were first identified over a decade ago [26], but their tissue distribution and function remain both unexplored and enigmatic.…”