Biomedical subjects

Z Sever

Publications and source records attributed to Z Sever.

3 recordsLinked to original sources

PubMed1998

Retinoic acid-receptor activation of SP-B gene transcription in respiratory epithelial cells.

Retinoids are known to play important roles in organ development of the lung. Retinoids exert their activity by modulating the expression of numerous genes, generally influencing gene transcription, in target cells. In the present work, the mechanism by which retinoic acid (RA) regulates surfactant protein (SP) B expression was assessed in vitro. RA (9-cis-RA) enhanced SP-B mRNA in pulmonary adenocarcinoma cells (H441 cells) and increased transcriptional activity of the SP-B promoter in both H441 and mouse lung epithelial cells (MLE-15). Cotransfection of H441 cells with retinoid nuclear receptor (RAR)-alpha, -beta, and -gamma and retinoid X receptor (RXR)-gamma further increased the response of the SP-B promoter to RA. Treatment of H441 cells with RA increased immunostaining for the SP-B proprotein and increased the number of cells in which the SP-B proprotein was detected. An RA responsive element mediating RA stimulation of the human SP-B promoter was identified. RAR-alpha and -gamma and RXR-alpha but not RAR-beta or RXR-beta and -gamma were detected by immunohistochemical analysis of H441 cells. RA, by activating RAR activity, stimulated the transcription and synthesis of SP-B in pulmonary adenocarcinoma cells.

Adenocarcinoma↗

PubMed1995

Upstream enhancer activity in the human surfactant protein B gene is mediated by thyroid transcription factor 1.

Surfactant protein B (SP-B) is selectively expressed in bronchiolar and alveolar epithelial cells of the lung. We identified an upstream enhancer located in the 5'-flanking region of the human SP-B gene (-439 to -331 base pair, hSP-B(-439/-331)) by deletion analysis of SP-B-luciferase constructs assessed in transfection assays in vitro. The element cis-activated the expression of an SV40 promoter-luciferase reporter gene in a human pulmonary adenocarcinoma cell line (H441-4). Three distinct binding sites for the nuclear transcription protein, thyroid transcription factor 1 (TTF-1), were identified, and the purified TTF-1 homeodomain was bound to bhe region of hSP-B(-439/-331). Co-transfection of H441-4 cells with the expression vector pCMV-TTF-1 trans-activated the native human SP-B promoter and the SV40 promoter fused with the SP-B enhancer. Mutations of the TTF-1 binding sites in the upstream enhancer blocked TTF-1 binding and transactivation activity. In summary, TTF-1 interacts with distinct proximal (-80 to -110) and distal (-439 to -331) cis-acting elements than regulate lung epithelial cell-specific transcription of the human SP-B gene.

Base Sequence↗

PubMed1991

Detection of P-glycoprotein with JSB-1 monoclonal antibody in B-5 fixed and paraffin-embedded cell lines and tissues.

We analyzed the expression of P-glycoprotein (Pgp) by immunohistochemistry using JSB-1 monoclonal antibody (MAb) on paraffin-embedded sections of the multi-drug resistant (MDR) (CHrC5 and CEM-VLB), and sensitive (AuxB1 and CEM) cell lines, and also in normal kidney, colon, adrenal and in kidney and colon carcinomas. After comparing the sensitivity of three different immunohistochemical techniques the peroxidase-antiperoxidase method was found to be the best. We then tested six different fixation methods. The MDR cell lines and human tissues demonstrated the strongest staining with B-5 fixative. Both MDR cell lines, but not the tissues fixed in 1% paraformaldehyde and Zamboni's fixative demonstrated weak staining. No immuno- reactivity could be detected in MDR cell lines and tissues fixed in 10% buffered or nonbuffered formalin or by the AMeX method of tissue processing. The present study clearly shows that the type of fixative is critical for the preservation of Pgp epitope recognized by JSB-1 MAb, and that B-5 fixative is expected to be equally applicable for the detection of Pgp in normal and neoplastic tissues.

ATP Binding Cassette Transporter, Subfamily B, Mem↗