Fig. 2: E2F1 knockdown induces cell death in human colon cancer cells. | Experimental & Molecular Medicine

Fig. 2: E2F1 knockdown induces cell death in human colon cancer cells.

From: E2F1 facilitates DNA break repair by localizing to break sites and enhancing the expression of homologous recombination factors

Fig. 2

a Apoptosis analysis of HCT116 and HT29 cells via flow cytometry. Colon cancer cells were incubated with siRNA in serum-free medium. The proportion of apoptotic cells was quantified using FITC-conjugated annexin V (1.5 μg/ml) and PI (20 μg/ml). Scatter plots illustrate the distribution of FITC-annexin V and PI staining for siControl- and siE2F1-transfected cells. The cells are classified as “live-cell” (bottom left), “early apoptotic-cell” (bottom right), “late apoptotic-cell” (top right) and “necrotic-cell” (top left). b Quantitative analysis of apoptotic cells in response to E2F1 knockdown. The bar graph shows the total percentages of early and late apoptotic cells determined by flow cytometry. FACS data was quantified using FlowJo software. Error bars denote the mean ± SD (n = 3). c The degree of DNA damage was measured via comet assay using Nikon Ti-E fluorescence microscopy. The lengths of fifty independent cell comet tails per sample were analyzed with Casp software (1.2.3beta2) (bottom). Three independent experiments were performed, and tail moments were measured (tail length × % of DNA in the tail). Error bars denote the mean ± SD (n = 3). ***P < 0.001 (Student’s t-test) indicates significance compared with siControl-treated cells. d Cell cycle profiles of human colon cancer cells treated with siE2F1 as characterized by flow cytometry. e Analysis of cell cycle progression by flow cytometry after siE2F1 transfection. The percentages of siControl-transfected and E2F1-deficient cells in S-phase were quantified with FlowJo software. Three independent experiments were performed. Error bars denote the mean ± SD (n = 3)

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