Search results for "VITRO"

Sex steroids, carcinogenesis, and cancer progression

2004

The relationship between sex steroids and cancer has been studied for more than a century. Using an original intact cell analysis, we investigated sex steroid metabolism in a panel of human cancer cell lines, either hormone responsive or unresponsive, originating from human breast, endometrium, and prostate. We found that highly divergent patterns of steroid metabolism exist and that the catalytic preference (predominantly reductive or oxidative) is strictly associated with the steroid receptor status of cells. We explored intra-tissue concentrations and profiles of estrogens in a set of human breast tumors as compared to normal mammary tissues, also in relation to their estrogen receptor s…

1-Methyl-?-carboline (Harmane), a potent endogenous inhibitor of benzodiazepine receptor binding

1980

The interaction of several beta-carbolines with specific [3H]-flunitrazepam binding to benzodiazepine receptors in rat brain membranes was investigated. Out of the investigated compounds, harmane and norharmane were the most potent inhibitors of specific [3H]-flunitrazepam binding, with IC50-values in the micromolar range. All other derivatives, including harmine, harmaline, and several tetrahydroderivatives were at least ten times less potent. Harmane has been previously found in rat brain and human urine, so it is the most potent endogenous inhibitor of specific [3H]-flunitrazepam binding known so far, with a several fold higher affinity for the benzodiazepine receptor than inosine and hy…

Structure-activity relationship studies of novel heteroretinoids: induction of apoptosis in the HL-60 cell line by a novel isoxazole-containing heter…

1999

In a search for retinoic acid receptor (RAR and RXR)-selective ligands, a series of isoxazole retinoids was synthesized and evaluated in vitro in transcriptional activation and competition binding assays for RARs and RXRs. In addition, these compounds were evaluated for their differentiating, cytotoxic, and apoptotic activities. In general, these derivatives showed scarcely any binding affinity and were not active in the transcriptional assay. However, among these isoxazole derivatives, the cis-isomer 14b was identified as a potent inducer of apoptosis, and its activity was found to be 6.5 and 4 times superior than that of 13-cis- and 9-cis-retinoic acids, respectively. On the other hand, c…

Species-specific mechanisms for cholesterol 7alpha-hydroxylase (CYP7A1) regulation by drugs and bile acids.

2005

The gene encoding cholesterol 7alpha-hydroxylase (CYP7A1) is tightly regulated in order to control intrahepatic cholesterol and bile acid levels. Ligands of the xenobiotic-sensing pregnane X receptor inhibit CYP7A1 expression. To retrace the evolution of the molecular mechanisms underlying CYP7A1 inhibition, we used a chicken hepatoma cell system that retains the ability to be induced by phenobarbital and other drugs. Whereas bile acids regulate CYP7A1 via small heterodimer partner and liver receptor homolog-1, mRNA expression of these nuclear receptors is unchanged by xenobiotics. Instead, drugs repress chicken hepatic nuclear factor 4alpha (HNF4alpha) transcript levels concomitant with a …

The polypyrimidine tract-binding protein (PTB) is involved in the post-transcriptional regulation of human inducible nitric oxide synthase expression.

2006

Human inducible nitric oxide synthase (iNOS) expression is regulated by transcriptional and post-transcriptional mechanisms. We have recently shown that the multifunctional RNA-binding proteins KH-type splicing regulatory protein and tristetraprolin are critically involved in the post-transcriptional regulation of human iNOS expression. Several reports have shown that KH-type splicing regulatory protein colocalizes with the polypyrimidine tract-binding protein (PTB), and both RNA-binding proteins seem to interact with the same mRNAs. Therefore we analyzed the involvement of PTB in human iNOS expression. In human DLD-1 cells, cytokine incubation necessary to induce iNOS expression did not ch…

Expression and trafficking of fluorescent viral membrane proteins in baculovirus-transduced BHK cells

2004

Baculovirus vectors show promise as a novel tool for gene delivery into mammalian cells and gene transfer with wild-type baculovirus has been demonstrated both in vitro and in vivo. To study expression and intracellular trafficking of foreign viral membrane proteins in baculovirus-transduced mammalian cells, the envelope proteins, E1 and E2, of rubella virus (RV) were chosen as a model. The enhanced green fluorescent protein (EGFP) and a red fluorescent protein (RFP) were fused to the C-terminus of E1 and E2, respectively. The proteins were cloned under a cytomegalovirus (CMV) promoter and expressed as fluorescent fusion proteins in baculovirus-transduced baby hamster kidney (BHK) cells. Ex…

Viability and Stimulation of Human Stem Cells from the Apical Papilla (hSCAPs) Induced by Silicate-Based Materials for Their Potential Use in Regener…

2020

Blood clot formation in the apical third of the root canal system has been shown to promote further root development and reinforcement of dentinal walls by the deposition of mineralized tissue, resulting in an advancement from traditional apexification procedures to a regenerative endodontic treatment (RET) for non-vital immature permanent teeth. Silicate-based hydraulic biomaterials, categorized as bioactive endodontic cements, emerged as bright candidates for their use in RET as coronal barriers, sealing the previously induced blood clot scaffold. Human stem cells from the apical papilla (hSCAPs) surviving the infection may induce or at least be partially responsible for the regeneration …

Foreed flushing of branch segments as a method for obtaining reactive explants of mature Quercus robur trees for micropropagation

1994

The aim of this study was to micropropagate mature Quercus robur L. trees when material retaining physiologically juvenile characteristics (stump sprouts, epicormic shoots) is not available. Branch segments from 70–300 year-old trees were force-flushed and the flushed, partially rejuvenated or reinvigorated shoots were used as a source of explants for establishment of cultures. In vitro establishment and multiplication was achieved with seven of the eight selected trees. The proliferation capacity of cultures of vertically placed explants declined after several subcultures, but efficient shoot multiplication was achieved by culturing decapitated shoots placed horizontally on GD medium suppl…

Comment On: Study on the Effects of Allitride and its Mechanisms on Renal Cell Carcinoma in Vitro

2011

Stimulation of protein (collagen) synthesis in sponge cells by a cardiac myotrophin‐related molecule from Suberites domuncula

2000

The body wall of sponges (Porifera), the lowest metazoan phylum, is formed by two epithelial cell layers of exopinacocytes and endopinacocytes, both of which are associated with collagen fibrils. Here we show that a myotrophin-like polypeptide from the sponge Suberites domuncula causes the expression of collagen in cells from the same sponge in vitro. The cDNA of the sponge myotrophin was isolated; the potential open reading frame of 360 nt encodes a 120 aa long protein (Mr of 12,837). The sequence SUBDOMYOL shares high similarity with the known metazoan myotrophin sequences. The expression of SUBDOMYOL is low in single cells but high after formation of primmorph aggregates as well as in in…