Statistical analyses for in vitro studies

For the aforementioned in vitro studies, statistical analyses were performed with the Prism software package (GraphPad Version 7, GraphPad Software, San Diego, California). Differences between 2 means were assessed by a 2-tailed paired or unpaired Student's t-test. Values of p < 0.05 were considered significant. For evaluating morphological, histological, and survival data, analysis of variance followed by Bonferroni correction was used to compare 3 groups. When sample number is not suffice to test for normality, nonparametric tests (Mann-Whitney U test or 1-way analysis of variance followed by Holm-Sidak’s test analysis) were used.