Expression of tumor-associated trypsinogens (TAT-1 and TAT-2) in prostate cancer.
ABSTRACT Trypsinogens are pancreatic serine proteinases and expressed in several cancers as tumor-associated trypsinogens (TAT). Trypsin mediates activation of pro-uPA and pro-MMPs, thus promoting angiogenesis and tumor invasion. Recently, we described expression of TAT in the human male genital tract and now we studied TAT in relation to PSA in PCa.
TAT expression was studied by immunohistochemistry, in situ hybridization, RT-PCR, DNA-sequencing and IFMA. LNCaP cells were used to study secretion of TAT and PSA after androgen stimulation.
Immunoreactive TAT was localized in all prostatic tumors (n = 109), lymph node (n = 16), and bone metastases (n = 17). Immunostaining intensity increased with higher Gleason's grade, whereas PSA immunostaining decreased significantly. PSA and TAT were not identically distributed in benign and malignant cells. Androgen stimulation of LNCaP cells decreased secretion of TAT and increased that of PSA. TAT mRNA was demonstrated in tissue sections and identified as TAT-1 and -2 by RT-PCR and DNA-sequencing.
Expression of TAT is better preserved than PSA in high-grade PCa. Expression of TAT and PSA is regulated by different mechanisms as demonstrated in tissue sections and in vitro. Locally produced TAT may act in a paracrine mode to promote angiogenesis and tumor invasion in PCa by both activating and degrading of other proteinases. Further studies on the role of TAT in invasive PCa and on the mechanisms involved in the regulation of TAT expression are warranted.
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ABSTRACT: N-myc downstream regulated gene-1 (NDRG1) is a metastasis suppressor that is down-regulated in prostate cancer. NDRG1 phosphorylation is associated with inhibition of metastasis and western blots indicate two bands at ~41 and ~46 kDa. Previous investigations by others suggest the higher band is due to NDRG1 phosphorylation. However, the current study using a dephosphorylation assay and the Phos-tag SDS-PAGE assay, demonstrated the 46 kDa NDRG1 protein band was not due to phosphorylation. Further experiments showed the NDRG1 protein bands were not affected upon glycosidase treatment, despite marked effects of these enzymes on the glycosylated protein, fetuin. Analysis using RT-PCR demonstrated only a single amplicon, and thus, the two bands could not a result from an alternatively spliced NDRG1 transcript. Western blot analysis of prostate cancer cell lysates identified the 41 kDa band to be a truncated form of NDRG1, with mass spectrometry confirming the full and truncated proteins to be NDRG1. Significantly, this truncated protein was not present in normal human prostate epithelial cells. Western blot analysis using anti-NDRG1 raised to its N-terminal sequence failed to detect the truncated protein, suggesting it lacked N-terminus amino acids (residues 1-49). Sequence analysis predicted a pseudotrypsin protease cleavage site between Cys49-Gly50. Such cleavage of NDRG1 in cancer cells may result in loss of NDRG1 tumour suppressive activity.Bioscience Reports 05/2013; · 1.88 Impact Factor
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ABSTRACT: The serine peptidase inhibitor, Kazal type 1 (SPINK1) has been suggested to define an aggressive molecular subtype of ERG-fusion negative prostate cancer. It was the aim of this study to further study the clinical relevance of SPINK1 expression and its relationship with other key genomic alterations of prostate cancer. A tissue microarray containing more than 10,000 prostate cancers with clinical follow-up was used for immunohistochemical SPINK1 analysis. Data on ERG status as well as PTEN, 6q, 5q, and 3p deletions were available for comparison. SPINK1 expression was absent in benign prostate glands and detectable in 5.9% of 9,503 interpretable prostate cancers. Presence of SPINK1 expression was markedly more frequent in ERG negative (10.4%) than in ERG positive cancers (0.3%; P < 0.0001). However, SPINK1 expression was unrelated to tumor phenotype and biochemical recurrence in all cancers and in the subgroup of ERG negative cancers. Further subgroup analyses revealed, however, that-within ERG negative cancers-SPINK1 expression was significantly linked to deletions at 6q15 (P < 0.0001) and 5q21 (P = 0.0042). Our results exclude SPINK1 as a relevant prognostic prostate cancer biomarker. However, the data demonstrate that SPINK1 overexpression is tightly linked to the small subsets of 6q15- and 5q21-deleted ERG negative prostate cancers. These findings support the concept of molecularly defined subtypes of prostate cancers. Prostate © 2013 Wiley Periodicals, Inc.The Prostate 07/2013; · 3.84 Impact Factor
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ABSTRACT: N-myc down-regulated gene 1 (NDRG1) is a known metastasis suppressor in multiple cancers, being also involved in embryogenesis and development, cell growth and differentiation, lipid biosynthesis and myelination, stress responses and immunity. In addition to its primary role as a metastasis suppressor, NDRG1 can also influence other stages of carcinogenesis, namely angiogenesis and primary tumour growth. NDRG1 is regulated by multiple effectors in normal and neoplastic cells, including N-myc, histone acetylation, hypoxia, cellular iron levels and intracellular calcium. Further, studies have found that NDRG1 is up-regulated in neoplastic cells after treatment with novel iron chelators, which are a promising therapy for effective cancer management. Although the pathways by which NDRG1 exerts its functions in cancers have been documented, the relationship between the molecular structure of this protein and its functions remains unclear. In fact, recent studies suggest that, in certain cancers, NDRG1 is post-translationally modified, possibly by the activity of endogenous trypsins, leading to a subsequent alteration in its metastasis suppressor activity. This review describes the role of this important metastasis suppressor and discusses interesting unresolved issues regarding this protein.Biochimica et Biophysica Acta 11/2013; · 4.66 Impact Factor