High Expression of Cathepsin E in Tissues but Not Blood of Patients with Barrett's Esophagus and Adenocarcinoma.

BACKGROUND: Cathepsin E (CTSE), an aspartic proteinase, is differentially expressed in the metaplasia-dysplasia-neoplasia sequence of gastric and colon cancer. We evaluated CTSE in Barrett's esophagus (BE) and cancer because increased CTSE levels are linked to improved survival in several cancers, and other cathepsins are up-regulated in BE and esophageal adenocarcinoma (EAC). METHODS: A total of 273 pretreatment tissues from 199 patients were analyzed [31 normal squamous esophagus (NE), 29 BE intestinal metaplasia, 31 BE with dysplasia (BE/D), 108 EAC]. CTSE relative mRNA expression was measured by real-time polymerase chain reaction, and protein expression was measured by immunohistochemistry. CTSE serum levels were determined by enzyme-linked immunosorbent assay. RESULTS: Median CTSE mRNA expression levels were ≥1,000-fold higher in BE/intestinal metaplasia and BE/D compared to NE. CTSE levels were significantly lower in EAC compared to BE/intestinal metaplasia and BE/D, but significantly higher than NE levels. A similar expression pattern was present in immunohistochemistry, with absent staining in NE, intense staining in intestinal metaplasia and dysplasia, and less intense EAC staining. CTSE serum analysis did not discriminate patient groups. In a uni- and multivariable Cox proportional hazards model, CTSE expression was not significantly associated with survival in patients with EAC, although CTSE expression above the 25th percentile was associated with a 41 % relative risk reduction for death (hazard ratio 0.59, 95 % confidence interval 0.27-1.26, p = 0.17). CONCLUSIONS: CTSE mRNA expression is up-regulated more than any known gene in Barrett intestinal metaplasia and dysplasia tissues. Protein expression is similarly highly intense in intestinal metaplasia and dysplasia tissues.

Repression of cathepsin E expression increases the risk of mammary carcinogenesis and links to poor prognosis in breast cancer.

Despite advances in detection and treatment for breast cancer (BC), recurrence and death rates remain unacceptably high. Therefore, more convenient diagnostic and prognostic methods still required to optimize treatments among the patients. Here, we report the clinical significance of the serum cathepsin E (CatE) activity as a novel prognostic marker for BC. Correlation analysis between the serum levels of CatE expression and clinicopathological parameters revealed that the activity levels, but not the protein levels, were negatively associated with the stages and progression of BC. Univariate and multivariate analyses demonstrated that the serum CatE activity was significantly correlated with favorable prognostic outcomes of the patients. The functional link of CatE expression to BC progression was further corroborated by in vivo and in vitro studies with mice exhibiting different levels of CatE expression. Multiparous CatE (-) (/) (-) mice spontaneously developed mammary tumors concomitant with morphological transformation and altered growth characteristics of the mammary glands. These alterations were associated in part with the induction of epithelial-mesenchymal transition and the activation of ß-catenin-dependent pathway in mammary cells. Loss of CatE strongly induced the translocation and accumulation of Wnt5a in the nuclei, thereby leading to the aberrant trafficking, maturation and secretion of Wnt5a and the impaired signaling. The interaction of CatE and Wnt5a was verified by proximity ligation assay and by knockdown or restoration of CatE expression in the mammary cells. Consequently, our data demonstrate that CatE contributes to normal growth and development of mammary glands through proper trafficking and secretion of Wnt5a.

Peroxynitrite induces senescence and apoptosis of red blood cells through the activation of aspartyl and cysteinyl proteases.

Changes in the oxidative status of erythrocytes can reduce cell lifetime, oxygen transport, and delivery capacity to peripheral tissues and have been associated with a plethora of human diseases. Among reactive oxygen and nitrogen species of importance in red blood cell (RBC) homeostasis, superoxide and nitric oxide radicals play a key role. In the present work, we evaluated subcellular effects induced by peroxynitrite, the product of the fast reaction between superoxide and nitric oxide. Peroxynitrite induced 1) oxidation of oxyhemoglobin to methemoglobin, 2) cytoskeleton rearrangement, 3) ultrastructural alterations, and 4) altered expression of band-3 and decreased expression of glycophorin A. With respect to control cells, this occurred in a significantly higher percentage of human RBC (approximately 40%). The presence of antioxidants inhibited these modifications. Furthermore, besides these senescence-associated changes, other important modifications, absent in control RBC and usually associated with apoptotic cell death, were detected in a small but significant subset of peroxynitrite-exposed RBC (approximately 7%). Active protease cathepsin E and mu-calpain increased; activation of caspase 2 and caspase 3 was detected; and phosphatidylserine externalization, an early marker of apoptosis, was observed. Conversely, inhibition of cathepsin E, mu-calpain, as well as caspase 2 and 3 by specific inhibitors resulted in a significant impairment of erythrocyte "apoptosis" Altogether, these results indicate that peroxynitrite, a milestone of redox-mediated damage in human pathology, can hijack human RBC toward senescence and apoptosis by a mechanism involving both cysteinyl and aspartyl proteases.

Association of cathepsin E deficiency with development of atopic dermatitis.

Atopic dermatitis (AD) is a pruritic inflammatory skin diseases associated with a family history of atropy. Here we show that mice lacking the endolysosomal aspartic proteinase cathepsin E spontaneously develop skin lesions similar to those of humans with AD when reared under conventional conditions but not under specific pathogen-free conditions. These mice showed the increase in the ratio of CD4+/CD8+ T cells, the strong polarization of naïve T cells to T helper 2 cells, and the systemic accumulation of IL-18 and IL-1beta accompanied by a marked increase in IL-4, IL-5, and IgE. The relative rates of degradation of IL-18 and IL-1beta were significantly lower in cathepsin E-deficient mice than wild-type mice. These results strongly suggest that the development of AD in cathepsin E-deficient mice is initiated by systemic accumulation of IL-18 and IL-1beta, mainly due to their reduced turnover rates. In addition, the reduced expression of cathepsin E was also observed in erythrocytes of both humans with AD and the AD mouse model NC/Nga. Cathepsin E deficiency might thus be responsible for the induction of AD in humans and mice.