CD44 knockdown inhibits MCF10DCIS xenograft tumor growth and invasion marker expression.

<p>DCIS-shLuc or DCIS-shCD44 cells (1.0×10⁶ cells) were injected into the mammary fat pad of nu/nu mice (n = 5 per group), and mammary tumor size was measured twice a week. (A) The xenograft tumors from DCIS-shCD44 cells showed significantly slower growth rate than that of DCIS-shLuc xenograft tumors (*<i>p</i><0.05, **<i>p</i><0.01). (B) The average tumor weight from DCIS-shCD44 cells was significantly smaller than that from DCIS-shLuc cells (*<i>p</i><0.05). (C) The mRNA expression levels of CD44 (21, the approximate qPCR cycle number of DCIS-shLuc tumors), MMP-9 (22) and uPA (22) were significantly down-regulated in DCIS-shCD44 xenograft tumors (n = 5) (*<i>p</i><0.05, **<i>p</i><0.01). (D) The protein levels of CD44v, CD44s, pSTAT3, and MMP-9 were markedly decreased in DCIS-shCD44 xenograft tumors. Three xenograft tumors from each group were combined for pooled samples. β-Actin was used as a loading control. (E) The protein levels of CD44 and pSTAT3 in DCIS-shLuc and DCIS-shCD44 xenograft tumors were determined by immunofluorescent staining of CD44 (red) and pSTAT3 (green). Nuclei were stained with TO-PRO-3 (blue).