DDIT3 and head and neck squamous cell carcinoma: SCC15 cells, a classical HPV-negative HNSCC, were treated with either control siRNA (siCtrl), si78 (CDS) or si78 (3’UTR), and assayed for levels of GRP78, as well as general apoptotic marker (cleaved-PARP), and ER-stress induced apoptotic marker (CHOP) in Western blots.