HOXD8 is a mediator of RA action.

<p>(<b>A</b>) qRT-PCR analysis of HOXD8 mRNA levels in BE(2)-C/Tet-Off cells with inducible expression of an shRNA sequence against Firefly <i>luciferase</i> (Luc-sh) or human <i>HOXD8</i> (HOXD8sh-1) in the absence of Doxy for 6 days. The <i>HOXD8</i> mRNA levels in BE(2)-C/Tet-Off/luc-sh cells in the presence of Doxy were designated as 1.0. The data were from two independent samples with each being assayed in triplicate and analyzed using two-tailed Student's <i>t</i>-test with the <i>p</i> values indicated. (<b>B–D</b>) Phase contrast imaging (<b>B</b>) and cell cycle analysis (<b>C–D</b>) of BE(2)-C/Tet-Off/Luc-sh and BE(2)-C/Tet-Off/HOXD8sh-1 cells that were cultured in the absence of Doxy for 6 days and then either untreated or treated with 10 µM RA for 3 or 6 days. The data in (<b>D</b>) were from three independent experiments and analyzed using two-tailed Student's <i>t</i>-test with the <i>p</i> values indicated. (<b>E</b>) qRT-PCR analysis of the mRNA levels of <i>CCNB1, CDK1,</i> and <i>RET</i> in BE(2)-C/Tet-Off/Luc-sh and BE(2)-C/Tet-Off/HOXD8sh-1 cells that were cultured in the absence of Doxy for 6 days and then treated with 10 µM RA for 6 days. The mRNA levels of the same genes in BE(2)-C/Tet-Off/Luc-sh cells cultured in the absence of Doxy without RA treatment were designated as 1.0 (dashed line). The data were from two independent samples with each being assayed in triplicate and analyzed using two-tailed Student's <i>t</i>-test with the <i>p</i> values indicated. Error bars (<b>A</b>, <b>D</b>, and <b>E</b>), SD.