The EIF2AK3 Knockout CAL-27 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout population derived from the CAL-27 human tongue squamous cell carcinoma line, designed for loss-of-function studies of EIF2AK3, the gene encoding PKR-like ER kinase (PERK). Supplied as a heterogeneous pool of edited cells, this product enables robust interrogation of PERK-dependent signaling without single-cell clonal expansion. The polyclonal format retains the genetic diversity of the parental tumor line while eliminating functional PERK, providing a versatile model for investigating the unfolded protein response (UPR) in oral cancer.
The parental CAL-27 cell line is a well-characterized adherent epithelial model originating from a human tongue squamous cell carcinoma. These tumorigenic cells display moderate differentiation and express epithelial markers, making them suitable for studies of oral squamous cell carcinoma (OSCC) progression, invasion, and therapeutic response. CAL-27 cells are routinely employed to examine molecular mechanisms underpinning head and neck cancer and to evaluate anti-cancer agents, including DNA-damaging drugs and proteasome inhibitors.
EIF2AK3/PERK is an ER-resident transmembrane kinase that acts as a primary sensor of endoplasmic reticulum stress. Under conditions of misfolded protein burden, Ca2? imbalance, or oxidative injury, PERK dissociates from the chaperone BIP/GRP78, oligomerizes, and autophosphorylates. Active PERK phosphorylates eIF2?? at Ser51, attenuating global mRNA translation while selectively promoting ATF4 synthesis. ATF4 induces downstream genes including CHOP (DDIT3) and GADD34 (PPP1R15A), which regulate apoptosis and feedback control of translation, respectively. PERK also modulates the IRE1?CXBP1 arm and activates NRF2 antioxidant programs. Prolonged activation upregulates pro-apoptotic Bcl-2 family members BIM and PUMA, thereby linking ER stress to cell death. This signaling nexus integrates adaptive and apoptotic outcomes, directing cell fate under proteotoxic stress.
Within oral squamous cell carcinoma, PERK signaling contributes to tumor growth, metastasis, and resistance to chemotherapy and proteasome inhibitors. Disruption of EIF2AK3 in CAL-27 cells using this polyclonal knockout model enables dissection of PERK??s role in cancer cell adaptation to the ER stress prevalent in the tumor microenvironment, including nutrient deprivation and hypoxia. The model permits evaluation of PERK??s impact on sensitivity to cisplatin, bortezomib, and other agents that exacerbate proteotoxic stress, and facilitates identification of synthetic lethal interactions exploitable in PERK-deficient tumors.
Representative experimental uses include western blotting for PERK and phospho?eIF2??, RT?qPCR for EIF2AK3 transcript, and monitoring of ATF4/CHOP induction following ER stressor treatment (e.g., tunicamycin, thapsigargin). Cell viability, apoptosis (Annexin V), and clonogenic assays measure cytotoxic responses under proteotoxic challenge, while migration and invasion assays assess metastatic potential. Drug sensitivity profiling with cisplatin or proteasome inhibitors, coupled with RNA?sequencing, allows comprehensive dissection of the integrated stress response. For further technical information, please contact Ascent Research.
