The rDNA antisense transcript PAPAS promotes lactogenic differentiation of mammary epithelial cells and suppresses breast cancer

PAPAS is an antisense transcript of rRNA genes and mediates silencing of the locus in non-dividing cells. Here, we have analyzed PAPAS function in lactogenic differentiation of mammary epithelial cells (HC11 cells) and in mammary cancer cells (4T1). Using doxycycline (Dox) inducible shRNA against PAPAS, we found that the knockdown perturbs differentiation and inhibits expression of lactogenic genes. In contrast, Dox-inducible overexpression of PAPAS in 4T1 cells suppresses genes required for ribosome biogenesis and slows down the neoplastic growth. Comparative gene expression analysis of total RNA-Seq data for murine mammary epithelial cells (untransformed cell line HC11 and cancer cell line 4T1).