Quantitative cell-cycle protein expression in oral cancer assessed by computer-assisted system

The knowledge of cell-cycle control has shown that the capacity of malignant growth is acquired by the stepwise accumulation of defects in specific genes regulating cell growth. Histologic diagnosis might be improved by a quantitative evaluation of more specific diagnosis biomarkers, which could help to precisely identify pre-malignant and malignant oral lesions. The aim of the present study is to evaluate whether computer-based quantitative assessment of p53, PCNA and Ki-67 immunohistochemical expression, could be used clinically to foresee the risk of oral malignant transformation. This retrospective study was carried out in ninety-five oral biopsies, 27 were classified as fibrous inflammatory hyperplasia, 40 as leukoplakia and 28 as oral squamous cell carcinoma. Sixteen out of the 40 leukoplakia were diagnosed as non-dysplastic leukoplakia, the other 24 being dysplastic leukoplakia, of which 50.0% were classified as moderate to severe dysplasia. Comparison of the four groups of oral tissues showed significant rises in p53 and Ki-67 positivity index, which increased steadily in the order benign, pre-malignant, and malignant. In contrast, it was not possible to relate higher PCNA levels with pre-malignant and malignant oral lesions. We therefore conclude that PCNA immunohistochemistry expression is probably an inappropriate marker to identify oral carcinogenesis, whereas joint quantitative evaluation of p53 and Ki-67, appears to be useful as a tumor marker, providing a pre-diagnostic estimate of the potential for cell-cycle deregulation of the oral proliferate status.

Expression of cell cycle regulatory proteins in epithelial components of dental follicles

Dental follicle is a component of tooth germs, which remain adjacent to the crown of unerupted or impacted teeth. Under the influence of pathologic changes, however, dental follicles that possess reduced epithelium can proliferate into stratified squamous epithelium as far as originate dental cysts. In order to clarify the role of apoptosis and cellular proliferation herein, expression of p53 and PCNA was examined in epithelial components of dental follicles associated with impacted third molars by means of immunohistochemistry. A total of 40 cases was included in this study being 22 cases with reduced epithelium and 18 cases with stratified epithelium. Expression of p53 expression was weak or not detected in dental follicles with reduced and stratified squamous epithelium. By contrast, PCNA positive cells were evidenced in basal and supra basal layers of the stratified squamous epithelium and in reduced epithelium of dental follicles, but without any significant statistically differences between them (P > 0.05). In conclusion, these data suggest that dental follicles possess proliferative activity as depicted by PCNA-positive nuclei in some epithelial cells. However, the biological behavior of dental follicles during the late stage of dental eruptive process may not be associated with deregulation of death and/or cell proliferation.

Abnormal cell-cycle expression of the proteins p27, mdm2 and cathepsin B in oral squamous-cell carcinoma infected with human papillomavirus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The Mechanism of Oocyte Activation Influences the Cell Cycle-Related Genes Expression During Bovine Preimplantation Development

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cell cycle arrest evidence, parasiticidal and bactericidal properties induced by L-amino acid oxidase from Bothrops atrox snake venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Toxicogenomic activity of gemcitabine in two TP53-mutated bladder cancer cell lines: special focus on cell cycle-related genes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cell cycle arrest and apoptosis in TP53 subtypes of bladder carcinoma cell lines treated with cisplatin and gemcitabine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Expression of genes related to apoptosis, cell cycle and signaling pathways are independent of TP53 status in urinary bladder cancer cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Viability and cell cycle analysis of equine fibroblasts cultured in vitro

This experiment aimed to study equine fibroblasts in culture analyzing and the cell cycle and viability of cells pre- and post-freezing. Skin fragments were obtained from 6 horses and cultured in DMEM high glucose + 10% FCS in 5% CO(2) until the beginning of confluence. Two passages were performed before freezing. Cells subjected to serum starvation (0.5% FCS) were analyzed for viability and cell cycle at 24, 48, 72, 96, 120, 144 and 168 h of culture. For the confluent groups, cells were analyzed at the moment they achieved confluence. Cellular viability was assisted with Hoescht 33342 and propidium iodide. The analysis of apoptosis/necrosis and cell cycle was performed using a flow cytometer (FACS Calibur BD(A (R))) after staining the cells with annexin V and propidium iodide. Both optical microscopy and flow cytometry confirmed that cellular viability was similar for serum starvation and confluent groups (average 84%). Similarly, both methods were efficient to synchronize the cell cycle before freezing. However, after thawing, serum starvation, for more than 24 h, was superior to culture for synchronizing cells in G0/G1 (69% x 90%). The results of this experiment indicate that equine fibroblasts can be efficiently cultured after thawing.

Anticlastogenic activity of aqueous extract of Agaricus blazei in drug-metabolizing cells (HTCs) during cell cycle

The mushroom Agaricus blazei has been extensively investigated because of evidence of its antimutagenic, antitumor, and anticarcinogenic activities. This study investigated the clastogenic and/or anticlastogenic activity of aqueous extract of Agaricus blazei (10% w/v) in drug-metabolizing rat hepatoma tissue cells (HTCs), with continuous treatment and treatment during different phases of the cell cycle. DNA damage was induced utilizing two directacting agents-methyl methane sulfonate and ethyl methane sulfonate-and two indirect-acting agents-2-aminoanthracene and cyclophosphamide. The aqueous extract of A. blazei with either continuous treatment or treatment during different phases of the cell cycle showed clastogenic activity. The results with continuous treatment showed that A. blazei does not protect against DNA damage-inducing agents that are direct acting. Meanwhile, when combined with indirect-acting agents, a protective effect was demonstrated. A protective effect was also found during different phases of the cell cycle when cells were treated with indirect-acting agents. The protective effects against indirect-acting agents (continuous treatment and during the different phases of the cell cycle) suggest that A. blazei may provide some health benefits to the public when used as a functional food.

Leishmania amazonensis Promastigotes Present Two Distinct Modes of Nucleus and Kinetoplast Segregation during Cell Cycle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cell cycle kinetics, apoptosis rates, DNA damage and TP53 gene expression in bladder cancer cells treated with allyl isothiocyanate (mustard essential oil)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)