The CASP3 Knockout NCI-H1975 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the NCI-H1975 non-small cell lung cancer (NSCLC) cell line, engineered to disrupt the CASP3 gene encoding executioner caspase-3. This polyclonal pool enables loss-of-function studies of caspase-3 in a heterogeneous, drug-resistant adenocarcinoma background without clonal artifacts.
NCI-H1975 is an epithelial cell line from a pleural effusion of a nonsmoking female with lung adenocarcinoma, harboring EGFR L858R/T790M mutations that drive oncogenic signaling and acquired resistance to first-generation EGFR tyrosine kinase inhibitors (TKIs). The line is KRAS and p53 wild-type, making it a well-characterized model for exploring EGFR TKI resistance, apoptosis evasion, and therapeutic intervention in NSCLC.
Caspase-3 serves as the principal executioner caspase, cleaving numerous substrates??including PARP, ICAD/DFF45, and lamin A/C??to effect apoptotic DNA fragmentation and cellular dismantling. It is activated downstream of initiator caspases (caspase-8 and -9), as well as granzyme B and p53, and is regulated by XIAP, survivin, and SMAC/Diablo. The intrinsic pathway proceeds via mitochondrial cytochrome c release, APAF-1 apoptosome formation, and caspase-9 activation, modulated by BID, BAX, and BAK. Caspase-3 also interfaces with TNF/NF-??B signaling and contributes to EGFR TKI resistance in NSCLC cells.
Knockout of CASP3 in NCI-H1975 abolishes the major executioner caspase activity, conferring resistance to apoptosis induced by death ligands, chemotherapeutics, and targeted agents. This model permits investigation of caspase-3-independent cell death mechanisms (e.g., necroptosis, ferroptosis) and non-apoptotic caspase-3 functions in migration, differentiation, and inflammation within an EGFR-mutant, TKI-resistant context. Consequently, the cells are valuable for dissecting apoptosis resistance as a determinant of therapeutic failure and for evaluating pro-apoptotic strategies.
Applications include screening for agents that restore apoptosis, assessing EGFR TKI combination therapies, and profiling compensatory survival networks via RNA-seq. Representative assays encompass Western blotting for caspase-3 and cleaved PARP, flow cytometry (Annexin V/PI), caspase-3 activity assays, TUNEL, and cell viability (MTT/CTG) under drug challenge. These polyclonal knockout cells also support functional studies of caspase-3??s non-apoptotic roles. For additional details or custom inquiries, contact Ascent Research.
