Fig. 4.

a MDA-MB-231, SKBR3, or MCF7 cells or b 66.1 or 410.4 or c 410 or 67 cells grown as MS-1, MS-2, or bulk cultures. mRNA harvested and analyzed for human or murine EP4 by qPCR. d–f The same cells analyzed for COX-2 mRNA expression. g Cell lysates of MDA-MB-231, SKBR3, or MCF7 cells grown as standard culture or in mammosphere (MS) assay and maintained in either DME media or mammocult (MC) media and immunoblotted for COX-2, EP4, or β-actin. h MDA-MB-231, SKBR3, or MCF7 cells grown as attached (open bar) or mammosphere (closed bar) in DME; conditioned media analyzed for PGE₂ by ELISA and expressed as Mean ± SE, pg/μg protein