Upmodulation by estrogen of HLA class I expression in breast tumor cell lines.
The expression of major histocompatibility complex (MHC) class I antigens was studied in five breast carcinoma cell lines before and after treatment with 17-beta estradiol. Increased HLA class I antigen expression correlated with the presence of estrogen receptors. The modulation of expression appeared to be mediated by transcriptional mechanisms, as revealed by class I mRNA levels. To elucidate the basis of MHC class I upregulation, we examined transcriptional factor binding activity to the class I regulatory element (CRE). Our results showed that 17-beta estradiol induced increases in factor binding activity to the CRE II probe, and decreases to the CRE I probe. In addition, our results suggested that factors that bind the CRE I region may modulate the binding of CRE II. Binding to CRE II was significantly increased in extracts pretreated with a competitor that contained the CRE I sequence, and that bound NF-kB/kBF1. In addition, induction of NF-kB binding activity by the tumor necrosis factor was accompanied by a decrease in nuclear factors that bind to the CRE II region.
Rodríguez
F
F
Servicio de Análisis Clínicos e Inmunología, Hospital Virgen de las Nieves, Universidad de Granada, Spain.
Perán
F
F
Garrido
F
F
Ruiz-Cabello
F
F
D001483:Base Sequence; D001943:Breast Neoplasms / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D002277:Carcinoma / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis* / Q000235:genetics; D051863:Host Cell Factor C1; D006801:Humans; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D050811:Octamer Transcription Factor-1; D015345:Oligonucleotide Probes / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C497692:HCFC1 protein, human; D015395:Histocompatibility Antigens Class I; D051863:Host Cell Factor C1; D016328:NF-kappa B; D050811:Octamer Transcription Factor-1; D015345:Oligonucleotide Probes; C494165:POU2F1 protein, human; D012333:RNA, Messenger; D014157:Transcription Factors; D004958:Estradiol