ATM and squamous cell carcinoma: By means of SKX cells, a squamous cell carcinoma cell line with ATM downregulation by miR-421 overexpression [24], we show loss of DNA-PKcs pulldown in synemin immunoprecipitates from unirradiated and irradiated ATM-depleted SKX cells, as shown in Figure 5C in lanes 6 and 8, relative to the ATM-expressing SAS cells, as shown in Figure 5C in lanes 5 and 7.