Novel Pactamycin Analogs Induce p53 Dependent Cell-Cycle Arrest at S-Phase in Human Head and Neck Squamous Cell Carcinoma (HNSCC) Cells
(A): TUNEL assay: 24-h treatment with increasing concentrations (100 and 500 nM) of TM-025 and TM-026 did not show a significant (p<0.05) number of TUNEL+ apoptotic cells (green fluorescence) marked with arrow-heads in SCC25 and SCC104 cells. DNase I (100 ul; 10 U/ml; positive control) treated cells were used as a positive control. (B-C): Autophagy was estimated as a measure of ratio of cellular LC3-II to LC3-I. (B) Western blot depicting levels of LC3-I and LC3-II in PCT analog-treated cells. (C) The ratio of LC3-II:LC3-I did not show a significant (P<0.05) induction (represented by *) of autophagy in the PCT analog-treated cells, in comparison to the positive control (cells treated with 100 μl of 50 ng/ml rapamycin). All sample groups were found to be identical to the vehicle-treated group at the same level of significance (i.e., P<0.05).