Fig. 4: Let-7a secreted by KYSE-150 cells increases the sensitivity of KYSE-150R cells to radiotherapy. | Cell Death & Disease

Fig. 4: Let-7a secreted by KYSE-150 cells increases the sensitivity of KYSE-150R cells to radiotherapy.

From: Mutual communication between radiosensitive and radioresistant esophageal cancer cells modulates their radiosensitivity

Fig. 4

A, B Real-time RT-PCR quantification of let-7a levels in the exosomes (A) and cell culture medium (B) of different esophageal squamous cancer cell lines. C, D KYSE-150R cells were incubated with either basal medium, KYSE-150-conditioned medium (culture medium collected from KYSE-150 cells), or basal medium supplemented with KYSE-150 exosomes for 48 h and exposed to different doses of radiation. Cell survival was determined using clonogenic assays (C), and DNA breaks were measured using comet assays (D). E, F KYSE-150R cells were incubated for 48 h with either basal medium, KYSE-150-conditioned medium, or basal medium supplemented with KYSE-150 exosomes. Intracellular levels of let-7a (E), Dicer, and IL-6 (F) were determined. G Real-time RT-PCR quantification of intracellular let-7a levels in KYSE-150R cells, KYSE-150 cells, and KYSE-150R cells co-cultured with KYSE-150 cells for 48 h. H–J KYSE-150R cells were transfected with either let-7a inhibitors or control inhibitors and incubated with either basal medium or basal medium supplemented with KYSE-150 exosomes for 48 h and exposed to different doses of radiation. Intracellular let-7a levels were quantified using real-time RT-PCR (H), cell survival was determined using clonogenic assays (I), and DNA breaks were measured using comet assays (J). Data (A–E, G–J) are expressed as the mean ± SD of the values from three independent experiments. **P < 0.01 (two-sided Student’s t test). K–M Subcutaneous xenografts of KYSE-150R cells were intratumorally injected with either KYSE-150 or KYSE-150R exosomes and exposed to 10 Gy of radiation, followed by an intratumoral injection of antagomir-let-7a or antagomir-Con. Xenograft tumors were photographed (K), the average volume was determined (L), and the volumes of irradiated xenografts relative to those of unirradiated xenografts were measured (M). Data (L, M) are expressed as the mean ± SD of the values obtained from five xenografts. *P < 0.05, **P < 0.01 (two-sided Student’s t test).

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