Cell counter

The apoptosis of CDDP-resistant LSCC cells was evaluated via TUNEL Apoptosis Assay kit [17 (link)]. After rising twice with PBS, cells were fixed by 4% paraformaldehyde followed by permeabilization with Triton-X 100. The cells were incubated in TUNEL assay solution (Invitrogen). Subsequently, TUNEL-stained cells were washed with PBS and counterstained with DAPI (Beyotime). Finally, TUNEL-positive cells were counted using a cell counter (BD Biosciences).

A TUNEL assay was used to analyze cell apoptosis. Briefly, cells were fixed with 4% paraformaldehyde for 1 h at 4°C and permeabilized with 0.1% Triton X-100 following treatment. TUNEL assay solution (Invitrogen; Thermo Fisher Scientific, Inc.) was subsequently incubated with the cells for 1 h at 37°C. Next, the TUNEL-stained cells were counterstained with DAPI (2 µg/ml; Beyotime Institute of Biotechnology) under antifade mounting medium for 15 min at room temperature. Images were acquired from five randomly selected fields of view using a fluorescence microscope (magnification, ×200). TUNEL-positive cells were counted using a cell counter (BD Biosciences).

The apoptosis of CRC cells was evaluated via InSitu Cell Death Detection kit (Roche, Germany) [23 (link)]. After rising twice with PBS, cells were fixed with 4% paraformaldehyde and permeabilized in 0.25% Triton-X 100. Subsequently, the cells were incubated with the TUNEL enzyme, and then counterstained with DAPI for 10 min. Finally, TUNEL-positive cells were counted using a cell counter (BD Biosciences).