Figure 5

Periostin is required for mesenchymal cell expansion and tumor invasion in residual tumors upon chemotherapy. (A) Tumor growth curve in MCF10DCIS xenografts upon PTX treatment and periostin knockdown. Vertical arrows indicate times of PTX administration, and horizontal arrow indicates administration period of doxycycline to knock down periostin. Tumor volume was measured on the indicated days and are presented as mean ± standard error (n = 10). *P < 0.05, Student’s t test. (B) Quantitative PCR analysis of Periostin gene in tumors collected at Day 30. Samples were prepared from a mixture of 10 tumors. Relative values are presented as mean ± standard error, *P < 0.02, Student’s t test. (C) Flow cytometry analysis of tumors at Day 30 using CD44 and CD24 antibodies. Samples were prepared from the mixture of 10 tumors. Ratio of CD44^high/CD24^low to CD24^high tumor cells is presented on the plots. (D) Immunofluorescence staining of CD44 and Ki67 in tumors collected at the end of the experiment. Scale bar, 100 µm. (E) Ratio of CD44^high/Ki67⁺ cancer cells against total Ki67⁺ cells was quantified at Day 30 (n = 15). Bars represent mean, and error bars represent standard deviation. ***P < 0.001, ****P < 0.0001, Mann-Whitney’s test. (F) Immunofluorescence staining of E-cadherin and Ki67 in tumors collected at the end of the experiment. Scale bar, 100 µm. (G) The ratio of E-cadherin−/Ki67+ cancer cells against total Ki67+ cells was calculated (n = 12). Bars represent mean, and error bars represent standard deviation. ****P < 0.0001, Mann-Whitney’s test. (H) Immunofluorescence staining of laminin-5 and periostin in tumors collected at the end of the experiment. Scale bar, 100 µm.