Fig. 6: NOTCH3 overexpression enhances chemoresistance of NPC in vivo.

A Xenograft tumor growth curve of S18 cells and S18 with stable overexpression of NICD3 (S18 OE) cells under different treatments. S18 and S18 OE cells were treated with 5 mg/kg paclitaxel or without for 16 days, as descried in Material and Methods. Error bars, mean ± SEM (n = 6 per group). *P < 0.05; **P < 0.01 (independent t-test). B Tumors were presented by photographs. Each group consists of 6 mice. C Bar graph shows the tumor weight at the 16th day post-treatment. Data are presented as the mean ± SD. *P < 0.05; **P < 0.01; ***P < 0.001 (independent t-test). D HE, KI-67, cleaved caspase-3 and NOTCH3 IHC staining of xenograft tumor. Up: Representative images. Scale bars 20 μm. Down: Z-score of KI-67, cleaved caspase-3, NOTCH3 in tumor sections with different treatments. IHC scores were calculated by multiply the scores for the proportion of positively-stained tumor cells (1, <10%; 2, 10%–50%; 3, 50%–80%; 4, >80%) and staining intensity (0, no staining; 1, weak; 2, moderate; 3, strong) by each investigator, then averaged. Z-score of IHC was defined by using the formula z = (x − μ)/ σ, where x is the raw IHC score, μ is the population mean, and σ is the population SD. Two-tailed t-test was used to calculate p-values. *P < 0.05; **P < 0.01; ***P < 0.001.