Retinoids block androgen-regulated formation and degradation of gap junctions.

<p>LNCaP-32 cells, grown to 70% confluence either in six well clusters or 10-cm dishes, were switched to charcoal-stripped, androgen-depleted (Strip) medium. Expression level of Cx32 and formation of GJs were analyzed by Western blot (<b>A</b>) and immunocytochemical analysis (<b>B</b>) after 48 h in the presence and absence of 9-CRA and ATRA (1 µM) and MB (2.5 nM) and DHT (10 nM). <b>C</b>. Formation of GJs was also analyzed by Western blot analysis of total, detergent-soluble and -insoluble fractions as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032846#s2" target="_blank">Materials and Methods</a>. Note that Cx32 and GJs are degraded in androgen-depleted medium and degradation is blocked upon replenishment with 9-CRA, ATRA, MB and DHT. Note also that only the expression level of Cx32 and its detergent solubility changed significantly whereas that of E-cadhiern (E-cad), β-catenin (β-cat) and ZO-1 was not significantly affected. In (B), the nuclei (green) were stained with DAPI. In A, 10 µg of total protein was analyzed.