Fig. 3: Let-7a increases the sensitivity of esophageal cancer cells to radiotherapy by regulating Dicer expression.

A Real-time RT-PCR quantification of let-7a levels in different esophageal squamous cancer cell lines. B, C KYSE-150R cells were co-transfected with a miR-Con/let-7a mimic and pcDNA3.1/pDicer, as indicated, and treated with different doses of radiation 48 h post transfection. Cell survival was determined using clonogenic assays (B), and DNA breaks were measured using comet assays (C). D, E KYSE-150 cells were co-transfected with an inhibitor-Con/let-7a-inhibitor and shCon/shDicer, as indicated, and treated with different doses of radiation 48 h post transfection. Cell survival was determined using clonogenic assays (D), and DNA breaks were measured using comet assays (E). Data (A–E) are expressed as the mean ± SD of the values from three independent experiments. **P < 0.01 (two-sided Student’s t test). F Subcutaneous xenografts of KYSE-150R cells were irradiated, followed by intratumoral injection of either agomir-let-7a or agomir-Con. Xenograft tumors were photographed (left), the average volume was determined (middle), and the volumes of irradiated tumors relative to those of unirradiated tumors were calculated (right). G Subcutaneous xenografts of KYSE-150 cells were irradiated, followed by intratumoral injection of antagomir-let-7a. Xenograft tumors were photographed (left), the average volume was determined (middle), and the volumes of irradiated tumors relative to those of unirradiated tumors were calculated (right). Data (F, G) are expressed as the mean ± SD of five xenografts. **P < 0.01 (two-sided Student’s t test).