Matrix metalloproteinases in dentin: Assessing their presence, activity, and inhibitors - a review of current trends

INTRODUCTION

Dentin integrity is a critical aspect of tooth structure, with matrix metalloproteinases (MMPs) playing a crucial role in dentinogenesis, caries formation, and dental bonding. It is crucial to accurately assess MMP activity to understand dentin pathophysiology and develop effective clinical strategies.

OBJECTIVES

The study aimed to conduct a thorough review and comprehensive summary of diverse techniques employed in assessing MMPs in dentin.

DATA AND SOURCES

To conduct the research, electronic databases were systematically searched and manual citation searches were performed. A total of 621 articles were identified. After eliminating duplicates and irrelevant studies, 70 articles were included in the review. 25 articles with overlapping methodologies were also excluded.

STUDY SELECTION

The selection criteria were based on the relevance of the studies to MMPs and MMP inhibitors in dentin without regard to the study design. Only peer-reviewed articles published in English were included. The search was restricted to studies published until November 2022.

CONCLUSION

The comprehensive analysis of various studies has yielded 37 techniques for evaluating MMPs and MMP inhibitors, which hold significant promise in creating diagnostic markers and devising targeted therapeutic interventions.

Increased shedding of soluble fragments of P-cadherin in nipple aspirate fluids from women with breast cancer

Breast cancer, a worldwide disease with increasing incidence, develops from ductal/lobular epithelium. Nipple aspirate fluid (NAF), secreted from the breast ducts and lobules, can be analyzed to assess breast metabolic activity. P-cadherin is frequently over-expressed in high-grade invasive breast carcinomas and has been reported to be an enhancer of migration and invasion of breast cancer cells, being correlated with tumor aggressiveness. The present study analyzed the soluble fragment of P-cadherin in milk, NAF and matched plasma samples of healthy subjects and in women with precancer conditions and breast cancer. Soluble P-cadherin was detected in all plasma and milk samples, and in about 31.3% of NAF samples. The lowest levels of soluble P-cadherin were found in plasma, with no significant difference among NoCancer, PreCancer and Cancer patients. The highest concentration of soluble P-cadherin was detected in milk collected during the first trimester of lactation, significantly with respect to all NAF samples. There were significantly higher levels of soluble P-cadherin in NAF from Cancer patients than those in women with NoCancer and PreCancer (P < 0.0001). Although no significant difference was found between in situ and invasive breast cancer, soluble P-cadherin levels were found at high concentrations in c-erbB-2-positive tumors, showing a positive correlation with disease stage grouping and tumor grade, and an inverse relationship with estrogen/progesterone receptor status. High levels of the soluble fragment of P-cadherin in Cancer NAF suggest its possible release via proteolytic processing, favoring cancer cell detachment from breast duct, and suggesting that measuring soluble P-cadherin in NAF may improve the identification of women with increased breast cancer risk.

Melatonin prevents apoptosis induced by UV-B treatment in U937 cell line

Melatonin influences circadian rhythms and acts as antioxidant and free radical scavenger. UV irradiation triggers multiple cellular events which lead to cell death, in particular to apoptosis; this process involves reactive oxygen species. Apoptotic machinery involves several pathways, in which mitochondria play crucial roles. In this work we have evaluated by means of cytometric, biochemical and ultrastructural approaches, if incubation of U937 promonocytic leukemia cells with melatonin may affect apoptotic behavior induced by UV-B. The cell line was treated with 1 mm melatonin before and after UV-B exposure. Melatonin pretreatment significantly reduced the number of apoptotic cells, as revealed by FITC Annexin-V and propidium iodide assays (P < 0.005), as well as attenuated mitochondria alterations, as shown by ultrastructural morphology, Mito Tracker and JC-1 staining, and cytochrome c (cyt c) release (P < 0.005). On the contrary, incubation with melatonin after UV-B exposure significantly protect U937 cells from UV-B induced alterations, showing a possible delay of the apoptotic machinery (as revealed by the presence of earlier stages of apoptosis and significant cyt c release). Our results suggest that, in our experimental model, melatonin may play a role as noncytotoxic anti-apoptotic compound and, at least in part, may protect U937 cells from UV-B induced mitochondria dysfunction/damage.

Flow cytometric evaluation ofVibrio parahaemolyticus adhesion inhibition to human epithelial cells

BACKGROUND

The present report demonstrates the usefulness of flow cytometry for a quantitative assessment of adhesion inhibition of a Vibrio parahaemolyticus strain to human epithelial cells to acquire more information about the nature of its adhesins.

METHODS

The inhibition of the adhesive process to Hep-2 was assayed by adding several monosaccharides to infected cells monolayers. The quantification of the adherent bacteria, labeled with a specific primary antibody plus a secondary fluorescein isothiocyanate-conjugated antibody, was performed by flow cytometry in comparison with light microscopy. The adherence was quantified in terms of the proportion of cells with adherent V. parahaemolyticus and as the mean of adherent bacteria per cell.

RESULTS

The adhesion showed a percentage of 98% with a mean fluorescence channel of 331 comparable to those obtained by light microscopy. The addition of monosaccharides resulted in a D-mannose and N-acetyl-galactosamine sensitive adherence. Even if this environmental strain also showed a mannose-sensitive cell-associated hemoagglutination that could mediate V. parahaemolyticus adherence, our results suggest that different sites for an irreversible adherence to host cell are involved.

CONCLUSIONS

Flow cytometry in combination with indirect immunofluorescence is an effective tool to investigate the adhesive process of bacteria to epithelial cells because it is more sensitive and reproducible than visual counting of bacteria performed in light microscopy.

Construction of tumor-specific toxins using ubiquitin fusion technique

The use of cytotoxic agents to eliminate cancer cells is limited because of their nonselective toxicity and unwanted side effects. One of the strategies to overcome these limitations is to use latent prodrugs that become toxic in situ after being enzymatically activated in target cells. In this work we describe a method for producing tumor-specific toxins by using a ubiquitin fusion technique. The method is illustrated by the production of recombinant toxins by in-frame fusion of ubiquitin to saporin, a toxin from the plant Saponaria officinalis. Ubiquitin-fused toxins were rapidly degraded via the ubiquitin-proteasome system, significantly reducing their nonspecific toxicity. The insertion of the protease-cleavage sequence between ubiquitin and saporin led to the removal of ubiquitin by the protease and resulted in protease-dependent stabilization of the toxin. We engineered toxins that can be stabilized by specific proteases such as deubiquitinating enzymes and prostate-specific antigen (PSA). Both constructs were activated in vitro and in cultured cells by the appropriate enzyme. Processing by the protease resulted in a greater than 10-fold increase in the toxicity of these constructs. Importantly, the PSA-cleavable toxin was able to kill specifically the PSA-producing prostate cancer cells. The ubiquitin fusion technique is thus a versatile and reliable method for obtaining selective cytotoxic agents and can easily be adapted for different kinds of toxins and activating proteases.

Differential distribution of soluble and complexed forms of prostate-specific antigen in cyst fluids of women with gross cystic breast disease

Gross cystic breast disease (GCBD) is the most common benign disease of the human female breast, and patients with GCBD have an increased risk of breast cancer. The aim of this study was to evaluate the distribution inside apocrine cells and in breast cyst fluids aspirated from gross cysts of prostate-specific antigen (PSA) molecular forms, and to correlate the different intracystic PSA profiles to the subpopulations of gross cysts. Type I cysts showed a median value of 0.71 microg/L of total PSA and 0.32 g/L of ACT, significantly different to that of Type II cysts (Wilcoxon P < 0.001). Although large excesses of ACT were detected in all samples, BCF samples and apocrine cells from Type I gross cysts contained about 70% of free PSA, compared to the higher amounts of complexed PSA found in Type II gross cysts. We demonstrate that in apocrine/secretive Type I breast gross cysts the serine protease PSA was mainly present in its free form, in contrast to a major proportion of complexed PSA found in flattened/transudative Type II cysts. Our results are consistent with the notion that a prolonged exposure of apocrine breast cells lining the Type I gross cysts to the proteolytic activity of PSA could be involved in the etiopathogenesis of GCBD.

The diagnostic and prognostic utility of prostate-specific antigen for diseases of the breast

Although prostate-specific antigen (PSA) is the most valuable tumor marker for the diagnosis and management of prostate carcinoma, it is widely accepted that PSA is not prostate specific. Numerous studies have shown that PSA is present in some female hormonally regulated tissues, principally the breast and its secretions. In this review, we summarize the findings of PSA in the breast, and focus on its potential for clinical applications in breast disease. PSA is produced by the majority of breast tumors and is a favorable indicator of prognosis in breast cancer. Low levels of PSA are released into the female circulation, and while the level of serum PSA is elevated in both benign and malignant breast disease, the molecular form of circulating PSA differs between women with and without breast cancer. These findings indicate that PSA may have potential diagnostic utility in breast cancer. PSA may also have a clinical application in benign breast disease, as both the level and molecular form of PSA differ between Type I and II breast cysts. High levels of PSA have been reported in nipple aspirate fluid (NAF) and recent studies have shown that the concentration of PSA in NAF is inversely related to breast cancer risk, indicating that NAF PSA may represent a clinical tool for breast cancer risk assessment. Thus, PSA represents a marker with numerous potential clinical applications as a diagnostic and/or prognostic tool in breast disease.

Prostate-specific antigen synthesis and secretion by human placenta: a physiological kallikrein source during pregnancy

Prostate-specific antigen (PSA), a kallikrein-like serine protease until recently thought to be prostate specific, has been demonstrated in various nonprostatic tissues and body fluids. PSA has been also found in human endometrium and amniotic fluids, even if the significance of this novel expression is unclear. In this study, we have demonstrated by multiple techniques that human placental tissue, obtained at delivery from normal full-term pregnancies, synthesizes and secretes PSA. RT-PCR showed the presence of PSA messenger ribonucleic acid; biochemical, chromatographic, and immunological studies revealed the expression of both free and complexed PSA forms; immunoelectron microscopy indicated the syncytiotrophoblast as the site of PSA synthesis and secretion. Moreover, in vitro experiments demonstrated that PSA production and secretion are up-regulated by 17beta-estradiol, a pregnancy-related steroid hormone. These results suggest that human placenta is a source of the PSA present in amniotic fluid and maternal serum during pregnancy.