miR-145 reduces tumorigenic potential of chemo-resistant (CR) colon cancer HT-29 cells in SCID mice. (A) administration of PEI/miR-145 complexes suppresses xenograft growth in SCID mice. CR HT-29 cells (2.5 × 105 cells) were injected with 50% Matrigel. Once palpable tumors developed (~3 weeks), the treatment (i.p.; weekly) was initiated. Upper panel shows intact xenograft tumor after treatment with PEI/miR-145 or the corresponding controls, and the lower panel shows the relative levels of miR-145 in the tumor after treatment with PEI/miR-145 or the corresponding controls. (B) qRT-PCR showing relative expression of CD44, CK20, β-Catenin, PDCD4 and Sox2 in tumors derived from CR HT-29 cells after treatment with PEI/miR-145 (miR145 Treated ) or the corresponding controls (Control). The data represent means ± SD of three independent experiments, *P < 0.001, compared to the control.