HELN were generated by transfection of cervical cancer HeLa cells with the ERE-betaGlobin-Luciferase-SV40-Neomycin plasmid.rnHELN hRAR alpha cells were generated by transfection of HELN cells with the pSG5-puro plasmid pSG5-human RAR alpha (ER alpha DBD)-puromycin.rnThe plasmid ERE-betaGlob-Luc-SVNeo contains a luciferase gene driven by estrogen receptor responsive element (ERE) in front of beta-globin promoter and a neomycin phosphotransferase gene under the control of SV40 promoter.rnThe pSG5-puro plasmid pSG5-human RAR alpha (ER alpha DBD)-puromycin enables to express the human retinoid receptor alpha in which the DNA binding domain (DBD) has been replaced by the estrogen receptor alpha DBD.rn