Immunelectron microscopic localization of cathepsin B in human exocrine glands

In Silico, In Vitro, and Clinical Investigations of Cathepsin B and Stefin A mRNA Expression and a Correlation Analysis in Kidney Cancer

The cysteine protease Cathepsin B (CtsB) plays a critical role in multiple signaling pathways, intracellular protein degradation, and processing. Endogenous inhibitors regulate its enzymatic activity, including stefins and other cystatins. Recent data proved that CtsB is implicated in tumor extracellular matrix remodeling, cell invasion, and metastasis: a misbalance between cathepsins and their natural inhibitors is often considered a sign of disease progression. In the present study, we investigated CtsB and stefin A (StfA) expression in renal cell carcinoma (RCC). mRNA analysis unveiled a significant CTSB and STFA increase in RCC tissues compared to adjacent non-cancerogenic tissues and a higher CtsB expression in malignant tumors than in benign renal neoplasms. Further analysis highlighted a positive correlation between CtsB and StfA expression as a function of patient sex, age, tumor size, grade, lymph node invasion, metastasis occurrence, and survival. Alternative overexpression and silencing of CtsB and StfA confirmed the correlation expression between these proteins in human RCC-derived cells through protein analysis and fluorescent microscopy. Finally, the ectopic expression of CtsB and StfA increased RCC cell proliferation. Our data strongly indicated that CtsB and StfA expression play an important role in RCC development by mutually stimulating their expression in RCC progression.

Microbiology of smegma: Prospective comparative control study

Purpose

The aim of the study was to investigate the common bacteria found in the smegma in the subpreputial space of asymptomatic boys prospectively, and to determine the difference of those bacteria according to the presence of smegma.

Materials and Methods

In our institution, 40 boys who performed penoplasty were recruited into the study. Swab was done using aseptic techniques on smegma and glans in the operation room. According to the presence of smegma in the subpreputial space, we classified glans as a group S (with smegma, n=20) and group C (without smegma, n=20). The swabs were immediately sent to microbiology laboratory for microscopy, culture, and sensitivity tests.

Results

The mean age was 30.4±26.4 months. Thirty-one bacteria were isolated from smegma, comprising 15 gram-positive species (48.4%) and 16 gram-negative species (51.6%). The most commonly isolated gram-negative bacterium was Escherichia coli (25.8%), while the commonly isolated gram-positive bacteria were Enterococcus faecalis (19.4%) and Enterococcus avium (12.9%). Most of the bacterial isolates were multi-drug-resistant (61.3%). In group S, 12 boys had 22 bacterial isolates in the glans. The commonly isolated bacteria were E. coli (27.3%), E. avium (22.7%) and E. faecalis (18.2%). In group C, 13 boys had 21 bacterial isolates in the glans. The most commonly isolated bacterium was E. faecalis (28.6%).

Conclusions

Smegma in the subpreputial space of children was colonized by many kinds of uropathogen.

Cathepsin B as a cancer target

INTRODUCTION

Cathepsin B is of significant importance to cancer therapy as it is involved in various pathologies and oncogenic processes in humans. Numerous studies have shown that abnormal regulation of cathepsin B overexpression is correlated with invasive and metastatic phenotypes in cancers. Cathepsin B is normally associated with the lysosomes involved in autophagy and immune response, but its aberrant expression has been shown to lead to cancers.

AREAS COVERED

This review highlights the oncogenic role of cathepsin B, discusses the regulation of cathepsin B in light of oncogenesis, discusses the role of cathepsin B as a signaling molecule, and highlights the therapeutic potential of targeting cathepsin B.

EXPERT OPINION

Targeting cathepsin B alone does not appear to abolish tumor growth, and this is probably because cathepsin B appears to have diverse functions and influence numerous pathways. It is not clear whether global suppression of cathepsin B activity or expression would produce unintended effects or cause the activation or suppression of unwanted pathways. A localized approach for targeting the expression of cathepsin B would be more relevant. Moreover, a combination of targeting cathepsin B with other relevant oncogenic molecules has significant therapeutic potential.

The carcinogenicity of smegma: debunking a myth

BACKGROUND

Smegma is widely believed to cause penile, cervical and prostate cancer. This nearly ubiquitous myth continues to permeate the medical literature despite a lack of valid supportive evidence.

METHODS

A historical perspective of medical ideas pertaining to smegma is provided, and the original studies in both animals and humans are reanalysed using the appropriate statistical methods.

RESULTS

Evidence supporting the role of smegma as a carcinogen is found wanting.

CONCLUSIONS

Assertions that smegma is carcinogenic cannot be justified on scientific grounds.

New applications of electron microscopy techniques in dermatopathology

The application of immunostaining techniques to electron microscopy specimens has led to a renewal of interest in electron microscopy in biological research in general, as well as in dermatopathology. Refinements in the preparative procedures have made easier the immunolocalization of antigens both in chemically-fixed and frozen unfixed tissues, embedded in plastic and sectioned. Application of these methods has led to the demonstration of the bullous pemphigoid antigen inside basal keratinocytes. HMB-45 antigen has been found to be present in premelanosomes. Recently, Factor XIIIa has been localized not only in dermal dendrocytes but also in endothelial cells and mast cells.

Immunocytochemical and immunoelectron microscopic demonstration of cathepsin B in human malignant melanoma

Proteases are known to enhance the spread of tumour cells. Possible sources of these proteases are the tumour cells themselves or fibroblasts in the tumour tissue. Immunological staining with anticathepsin B antibody indicates that the subcellular distribution of cathepsin B in tumour cell lines differs from that in normal liver. The aims of this study were: (i) to show whether different types of melanoma differ in their production of cathepsin B; (ii) to identify the cathepsin B-producing cells; and (iii) to determine the subcellular distribution of cathepsin B in melanoma cells. All types of melanomas contained cell regions stained with anticathepsin B antibody. The intensity of the stain and the number of cells reacting with anticathepsin B antibody depended on the size of the tumour but not on the type of melanoma. Epithelioid cells stained more intensely with anticathepsin B antibody than spindle-shaped cells. Cells staining with anticathepsin B antibody were almost exclusively tumour cells. Anticathepsin B stain was located mainly in vesicular structures which did not contain a filamentous matrix. Additional anticathepsin B stain was detected at the extracellular spaces. Hypomelanotic melanoma cells, mainly of the epithelioid type, produced most of the cathepsin B. Cathepsin B may be involved in both the degradation of possibly abnormal melanosomes and the focal degradation of the extracellular matrix.

Techniques in immuno-electron microscopy. I. Cryosubstitution

Normal skin was cryoprotected by submerging it in a mixture of 30% dimethylformamide (DMF) in PBS or RPMI. Subsequently it was frozen in liquid propane gas. Cryosubstitution was carried out at -90 degrees C by using methanol to which uranyl acetate or osmium tetroxide were added. The tissue was embedded in either Lowicryl K4M at -40 degrees C or in Epon at +60 degrees C. The tissue was evaluated by its overall preservation of ultrastructural details and by its labeling intensity after incubation with either anti-desmoglein or anti-type VII collagen monoclonal antibodies. The mixture of DMF and PBS caused an electron-dense precipitate within the cell. The overall morphology was better in Epon-embedded material than in K4M-embedded material. However, the labeling was best in K4M material. Regardless of whether the tissue was embedded in Epon or K4M, the addition of osmium tetroxide markedly reduced the degree of labeling.