A protective role for FADD dominant negative (FADD-DN) mutant in trinitrochlorobenzene (TNCB)-induced murine contact hypersensitivity reactions

HS3ST1 Promotes Non-Small-Cell Lung Cancer Progression by Targeting the SPOP/FADD/NF-κB Pathway

Heparan sulfate proteoglycan is a key component of cell microenvironment and plays an important role in cell-cell interaction, adhesion, migration, and signal transduction. Heparan sulfate 3-O-sulfotransferase 1 (HS3ST1) is a metabolic-related gene of HS. The present study was aimed at exploring the role of HS3ST1 in the progress of non-small-cell lung cancer (NSCLC). Our results illustrated that HS3ST1 promoted the malignant behaviors of NSCLC cells both in vitro and in vivo. HS3ST1 was found to inhibit spot-type zinc finger protein (SPOP) expression, which might inhibit the NF-κB pathway activation through mediating the degradation of Fas-associated death domain protein (FADD). By analyzing NSCLC patient samples, we also found increased HS3ST1 expression and decreased SPOP expression in tumor tissues in contrast with those in adjoining normal tissues. In conclusion, HS3ST1 promotes NSCLC tumorigenesis by regulating SPOP/FADD/NF-κB pathway.

SPOP promotes FADD degradation and inhibits NF-κB activity in non-small cell lung cancer

FAS-associated protein with death domain (FADD) is the pivotal adaptor protein, which transmits apoptotic signals mediated by the death receptors. Here we report that high FADD protein level predicts poor prognosis of non-small cell lung cancer (NSCLC) patients and its protein level is mainly regulated by the 26S proteasome. We also found that ubiquitin ligase SPOP (speckle-type POZ protein) binds to FADD and mediates its degradation, which can be blocked by MG132 treatment. Notably, SPOP inhibits NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activity and its target genes expression via FADD. These results reveal the function of SPOP-FADDNFκB axis in NSCLC cells, which is associated with prognosis of NSCLC patients.