Enhanced expression of tumour suppressor RAR-β by DSPC nano-formulated lipo-ATRA in the lung of B16F10 cell-implanted C57BL6 mice and in A549 cells

All Trans Retinoic acid (ATRA) is an efficient drug for leukemia, but is not efficient therapy for solid cancers. Hence we have used 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and cholesterol lipo-ATRA to investigate its molecular therapeutic effect on lung cancer. The objective was to find whether it could enhance ATRA receptor, RAR-β expression in lung cells as it was lost in majority of cancers including lung cancer. The study was made in an experimental C57BL/6 mice model developed by tail vein injection of B16F10 cells and in A549 human lung cancer cells. The RAR-β protein expression was studied by Immunohistochemistry/Immunocytochemistry and the mRNA expression was studied by RT-PCR and qPCR methods. Both free and lipo-ATRA treatments showed an enhancement of RAR-β protein and gene expressions, indicating its induction on RAR β. However, lipo-ATRA treatment has shown significant induction when compared with free ATRA treatment. Our results implies that the DSPC lipo-ATRA treatment might have accumulated more ATRA in to the target cells which might have resulted in the induction of its receptor RAR-β expression in a hypothesis of ligand induced receptor expression.