miR 204-5p inhibits apoptosis in dacarbazine-treated melanoma cells

Melanoma is one of the most aggressive types of malignant tumors, commonly affecting young individuals. The treatment of metastatic tumors remains obscure due to the resistance of tumor cells to drugs mediated by various mechanisms. The acquisition of a resistant phenotype is associated with both genetic and epigenetic alterations in cancer cells. Therefore, the current study aimed to investigate whether microRNA (miR)-204-5p could promote alterations in the cell cycle and apoptosis of dacarbazine (DTIC)-treated melanoma cells. Quantitative real time PCR showed that transfection of DTIC-treated SK-MEL-2 melanoma cells with miR-204-5p mimics significantly upregulated miR-204-5p. However, flow cytometric analysis revealed that the proportion of cells in different phases of the cell cycle remained unchanged. Additionally, the proportion of early apoptotic cells was notably enhanced following cell treatment with DTIC, accompanied by a profound increase in Ki-67 negative cells, as verified by an immunofluorescence assay. Furthermore, miR-204-5p overexpression reduced the percentage of early apoptotic DTIC-treated melanoma cells. The proportion of Ki-67 negative cells was only increased by 3%. Overall, the results of the current study indicated that miR-204-5p overexpression could mostly attenuate cell apoptosis in DTIC-treated cells rather than promote their transition from the G0 phase of the cell cycle in response to chemotherapeutic agent-induced stress.     

RGC-32与细胞周期调控

RGC-32(response gene to complement-32)是一种重要的补体应答分子,同时也参与了许多其他生物学功能.近来的研究发现RGC-32为细胞周期G2/M检测点关键调控分子,在细胞周期精细调控过程中发挥重要作用,并参与细胞增殖分化、再生修复、炎症反应、肿瘤形成等多种生物学过程.但RGC-32对细胞周期确切的调控机制有待阐明.该文就RGC-32基因及其生物学功能、细胞周期调控以及两者之间的调控关系等作一简要综述.     

Continuous fever-range heat stress induces thermotolerance in odontoblast-leneage cells

Objective

Heat shock during restorative procedures can trigger damage to the pulpodentin complex. While severe heat shock has toxic effects, fever-range heat stress exerts beneficial effects on several cells and tissues. In this study, we examined whether continuous fever-range heat stress (CFHS) has beneficial effects on thermotolerance in the rat clonal dental pulp cell line with odontoblastic properties, KN-3.

Methods

KN-3 cells were cultured at 41 °C for various periods, and the expression level of several proteins was assessed by Western blot analysis. After pre-heat-treatment at 41 °C for various periods, KN-3 cells were exposed to lethal severe heat shock (LSHS) at 49 °C for 10 min, and cell viability was examined using the MTS assay. Additionally, the expression level of odontoblast differentiation makers in surviving cells was examined by Western blot analysis.

Results

CFHS increased the expression levels of several heat shock proteins (HSPs) in KN-3 cells, and induced transient cell cycle arrest. KN-3 cells, not pre-heated or exposed to CFHS for 1 or 3 h, died after exposure to LSHS. In contrast, KN-3 cells exposed to CFHS for 12 h were transiently lower on day 1, but increased on day 3 after LSHS. The surviving cells expressed odontoblast differentiation markers, dentine sialoprotein and dentine matrix protein-1. These results suggest that CFHS for 12 h improves tolerance to LSHS by inducing HSPs expression and cell cycle arrest in KN-3 cells.

Conclusions

The appropriate pretreatment with continuous fever-range heat stress can provide protection against lethal heat shock in KN-3 cells.     

Isolation and cultivation of neuronal precursor cells from the developing human enteric nervous system as a tool for cell therapy in dysganglionosis

Background The human enteric nervous system (ENS) descends from migrating neural crest cells (NCC) and is structured into different plexuses embedded in the gastrointestinal tract wall. The development of this entity strongly depends on the supply of an appropriate support with trophic factors during organogenesis. The lack of important factors, such as glial cell line-derived neurotrophic factor, leads to severe disturbances in the ENS and, thus, to motility disorders in children. The isolation of neuronal precursor cells as well as their transplantation after expansion in vitro is therefore a hopeful new approach concerning all forms of dysganglionosis in children.Methods We therefore established a way to isolate and expand precursor cells from the developing and postnatal human ENS. Bowel samples were obtained from human fetuses and children (from the 9th week of gestation to 5 years postnatal). Myenteric plexus was isolated by enzymatical digestion and cultivated until spheroid aggregates, the so-called neurospheres, developed. These neurospheres could be differentiated and also be transplanted after dissociation into aganglionic bowel in vitro.Results Enteric neurospheres could be grown from different gestational ages, including postmortem material. Undifferentiated proliferating precursor cells were kept in culture for up to 72 days and could be differentiated in neurons and glial cells in vitro.Conclusion The first results using isolated enteric neurospheres in aganglionic bowel are quite promising and are a basis to develop an appropriate cell therapy for all kinds of dysganglionosis, especially for cases where a surgical approach is not sufficient or not even possible.     

Eicosapentaenoic acid (EPA) reduces crypt cell proliferation and increases apoptosis in normal colonic mucosa in subjects with a history of colorectal adenomas

Background and aims Omega-3 fatty acids in fish oil exert a protective effect on the development of colorectal cancer in animal models. Patients with colorectal adenomas have been shown to have increased crypt cell proliferation and decreased apoptosis in macroscopically normal appearing colonic mucosa. We investigated whether dietary supplementation with eicosapentaenoic acid (EPA) could alter crypt cell proliferation and apoptosis in such patients. Patients/methods Thirty subjects were randomised to either 3 months of highly purified EPA in free fatty acid form (2 g/day) or to no treatment. Colonic biopsies were taken at the initial colonoscopy and repeated 3 months later, and analysed for cell proliferation and apoptosis (immunohistochemistry) and mucosal fatty acid content. Results/findings Crypt cell proliferation was significantly reduced whilst apoptosis was significantly increased after EPA supplementation. Neither crypt cell proliferation nor apoptosis were altered in the control group. EPA in the mucosa increased significantly after EPA supplementation, whereas there was no significant change in controls. Conclusions Dietary supplementation with EPA significantly increases levels of this fatty acid in colonic mucosa, associated with significantly reduced proliferation and increased mucosal apoptosis. Further studies are needed to assess the potential efficacy of EPA supplementation in preventing polyps in the chemoprevention of colorectal cancer.     

Histogenesis of microscopic adenoma and hyperplastic (metaplastic) gland in nonpolyposis coli

Histogenesis of microscopic adenoma in nonpolypoid colons (those not included in the special disease group of familial polyposis coli) was investigated using complete serial sections with the following results: Adenoma arises from basal cells in the deep layer of the mucosa; and two types of basal cells found were 1) those which had already undergone changes to adenoma and 2) those which are in their transitional stage to adenomas. Early-phase growth of adenoma is brought about by branching. Individual hyperplastic (metaplastic) glands constituting so-called hyperplastic (metaplastic) polyps are considered to be only an expression of one variant in the growing process of adenomas and the glands showing these changes most characteristically have a serrated pattern. Based on these findings, the histogenesis of adenoma in nonpolypoid colons is shown schematically.     

Expression of vitamin D receptor in lung cancer

The active metabolite of vitamin D 1,25-dihydroxycholecalciferol is a hormone-like agent that regulates cell differentiation and proliferation. Various vitamin D derivatives have been shown to induce differentiation in neoplastic cells. The prerequisite for any hormone action is the presence of its receptor. We studied the expression of vitamin D receptor in human lung cancer cell lines and in primary lung cancer tissue. Employing the polymerase chain reaction, 10 out of 11 cell lines stemming from small-cell lung cancer and 15 out of 15 cell lines stemming from non-small-cell lung cancer demonstrated vitamin D receptor expression. An immunohistochemical analysis, using a specific monoclonal antibody, demonstrated vitamin D receptor protein expression in 31 out of 117 (26%) primary small-cell lung cancer cases tested. Positive cells exhibited a nuclear reaction pattern. Twenty-one out of 37 primary non-small-cell lung cancer cases, particularly adenocarcinomas (9/14) and squamous-cell carcinomas (10/15), exhibited vitamin D receptor. Results indicate that a subset of lung cancer cases may be susceptible to the differentiating effects of vitamin D analogues.