The ATF6 Knockout DLD-1 Polyclonal Cells product comprises a CRISPR/Cas9-edited polyclonal knockout cell population in which the ATF6 gene has been disrupted in the human DLD-1 colorectal adenocarcinoma cell line. This pooled knockout model allows investigation of ATF6-dependent functions without clonal selection, preserving heterogeneous genetic backgrounds inherent to polyclonal populations. The loss-of-function approach disrupts the endogenous ATF6 locus, enabling direct interrogation of its role in the unfolded protein response (UPR) and ER stress signaling pathways across a population-level context.
DLD-1 cells are derived from a human colorectal adenocarcinoma classified as Dukes’ type C, characterized by microsatellite instability (MSI-high) and a KRAS G13D activating mutation. This genetic profile renders DLD-1 a widely used model for studying colorectal cancer biology, tumor progression, and therapy resistance mechanisms. The MSI-high status and constitutive MAPK pathway activation via mutant KRAS provide a relevant substrate for dissecting how ER stress sensors like ATF6 intersect with oncogenic signaling networks.
ATF6 encodes an ER-resident transmembrane protein that acts as a primary stress sensor. Under basal conditions, ATF6 is retained in the ER through interaction with the chaperone BiP/GRP78. Upon accumulation of unfolded proteins, BiP/GRP78 dissociates, permitting ATF6 trafficking to the Golgi apparatus where sequential cleavage by site-1 protease (S1P/MBTPS1) and site-2 protease (S2P/MBTPS2) releases the active cytosolic fragment ATF6f. This transcription factor translocates to the nucleus and, often in concert with NF-Y and spliced XBP1, drives expression of ER chaperones (HSPA5/BiP, CALR, CANX), folding enzymes (DNAJB9, DNAJC3), and components of ER-associated degradation (ERAD) such as HERPUD1. Thus, ATF6 coordinates adaptive UPR outputs that restore proteostasis, while also engaging with parallel branches involving IRE1 and PERK/ATF4/CHOP signaling.
In DLD-1 cells, ATF6 knockout provides a unique tool to dissect the contribution of the ATF6 arm of the UPR to colorectal cancer cell survival, particularly under conditions of ER stress induced by nutrient deprivation, chemotherapeutic agents, or oncogenic load. Given the high basal ER stress often present in solid tumors, disabling ATF6-mediated transcriptional adaptation may reveal vulnerabilities linked to protein folding and secretion demands. The MSI-high and KRAS-mutant background further permits examination of crosstalk between ATF6 signaling and DNA repair deficiency or MAPK-driven growth, potentially uncovering synthetic lethal interactions or resistance factors relevant to colon cancer treatment.
Applications include ER stress induction experiments using tunicamycin or thapsigargin, followed by western blot analysis of ATF6 cleavage and UPR target induction (e.g., BiP), RT-qPCR profiling of ATF6-dependent transcriptional programs, cell viability and apoptosis assays under proteotoxic stress, and luciferase reporter assays for UPR element activation. Immunofluorescence can assess ATF6 subcellular redistribution. This polyclonal knockout population is suitable for pooled functional genomics, drug screening, and mechanistic studies exploring how ATF6 modulates colorectal cancer biology and response to proteostasis-disrupting therapies. For further details and customization, please contact Ascent Research.
