Inactivation of JAK1/2 in fibrosarcoma cells leads to loss of invasion in vitro and metastasis in vivo, and in zebrafish these cells show limited spread throughout the zebrafish body compared with the highly metastatic parental cells.
To determine the role of the Janus tyrosine kinase (JAK)-STAT pathway in NF-kappaB activation by IFN, we examined NF-kappaB activation in JAK1-deficient mutant human fibrosarcoma cells.
We investigated the functionality of the Jak1 SH2 domain by stably reconstituting Jak1-defective human fibrosarcoma cells U4C with endogenous amounts of Jak1 in which the crucial arginine residue Arg466 within the SH2 domain has been replaced by lysine.