Figure 1.

miR-302a expression is downregulated in CRC. A, B qPCR analysis was used to assess miR-302a expression in cetuximab (CTX)-resistant (CC-CR) and CTX-sensitive (CC) cell lines in a 3D culture system (A) and in 3 CTX-resistant patient-derived xenografts (PDXs) (B). C, D qPCR analysis was used to assess miR-302a expression in 13 human CRC cell lines, an immortalized normal human intestinal epithelial cell line, HIEC (C), and 20 paired CRC tissue and adjacent normal tissue samples (D). E Representative images and analysis of fluorescence in situ hybridization (FISH) assays for miR-302a in 90 paired CRC and adjacent normal tissue samples are shown. Scale bar, 100 μm (top) and 50 μm (bottom). **P<0.01, χ² test. F Kaplan-Meier overall survival curves were constructed for CRC patients (n=90) who were divided into low- and high-miR-302a expression groups. Significance was determined by log-rank test. Transcript levels were normalized to U6 expression. The values represent the mean ± SEM. A-D *P<0.05, **P<0.01, Student's t test. N.S., not significant. Data are representative of three independent experiments.