RAR-beta2 mRNAs increase signs the normal differentiation of the human bronchial epithelium while a decrease is observed in most lung cancer cell lines.
Mice that develop lung cancer from activation of a latent K-ras oncogene had high intratumoral JNK activity and low RARalpha levels and were resistant to treatment with an RAR ligand.
In addition we analyzed the expression of another RAR isoform, alpha2, in many tumor-derived lines and conclude from its expression pattern that RARalpha2 is unlikely to be involved in retinoic acid growth suppression of lung cancer.
We report the isolation and characterization of genomic sequences coding for the 5' end of human retinoic acid receptor beta 1, a fetal RAR isoform which is also expressed in small cell lung cancers.