The ITSN1 Knockout NCI-H1975 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population targeting the ITSN1 gene in the NCI-H1975 human lung adenocarcinoma line. This loss-of-function model enables investigation of ITSN1??s scaffolding functions in endocytosis, signal transduction, and actin dynamics without the artifacts of clonal selection. The heterogeneous knockout profile provides a physiologically relevant system to dissect ITSN1-dependent cellular processes in cancer research.
NCI-H1975 is an epithelial cell line derived from a metastatic lung lesion of a female patient with adenocarcinoma, harboring the oncogenic EGFR L858R mutation. This mutation drives constitutive activation of the MAPK/ERK and PI3K-AKT signaling pathways, recapitulating EGFR-addicted non-small cell lung cancer. The line is widely employed for studying EGFR-targeted therapies and tumor progression, making it a relevant background for assessing the impact of ITSN1 disruption on drug sensitivity and metastatic behavior.
ITSN1 functions as a multimodular scaffold connecting clathrin-mediated endocytosis to actin cytoskeleton remodeling. The long isoform ITSN1-L possesses GEF activity for Cdc42, promoting GTPase activation and downstream signaling through PAK, N-WASP, and the Arp2/3 complex. ITSN1 coordinates EGFR internalization by interacting with adaptors (Eps15, Epsin, AP-2), fission machinery (dynamin, synaptojanin), and signaling effectors (Sos1, PI3KC2??). It couples the receptor to the GRB2-SOS1-RAS-RAF-MEK-ERK cascade and the PI3K-AKT pathway, while upstream Src kinases and PI3K modulate ITSN1 activity. This positions ITSN1 as a critical node linking membrane trafficking to oncogenic signaling.
Knockout of ITSN1 in NCI-H1975 cells is expected to impair EGFR internalization and attenuate ERK and AKT pathway activation, potentially reducing the oncogenic drive of EGFR L858R. Loss of Cdc42 regulation may disrupt actin-based motility, diminishing migration and invasion, which are hallmarks of metastasis. This model enables dissection of endocytosis-dependent versus -independent EGFR signaling and may reveal adaptive mechanisms that contribute to therapeutic resistance, offering a platform to study compensatory network rewiring.
Typical research applications include western blotting for phosphorylated EGFR, ERK1/2, and AKT; immunofluorescence to monitor receptor internalization kinetics; and RT-qPCR for transcriptional changes. Migration and invasion can be quantified using Boyden chamber assays, while drug sensitivity profiling with EGFR inhibitors like erlotinib can probe resistance mechanisms. Co-immunoprecipitation with ITSN1 interactors such as Eps15, dynamin, or Sos1 may be employed to explore signaling complexes. For technical inquiries or assay guidance, contact Ascent Research.
