BID is a critical factor controlling cell viability regulated by IFN-α

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Clinical use of human interferon-alpha (IFN-α) shows variable success, with key molecules regulating cell viability remaining unidentified.
• Previous research indicated that interfering with the IFN (α, β, and ω) receptor (IFNAR) 1/2 and IFN regulatory factor 9 restored cell viability in IFN-α-sensitive ovarian cancer cells.

Purpose of the Study:

• To identify key molecules and pathways through which IFN-α regulates cell viability, particularly in the context of apoptosis.
• To investigate the role of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and BH3 interacting domain death agonist (BID) in IFN-α-mediated cell death.
• To explore the potential of targeting the BID pathway for IFN-α-resistant cancers.

Main Methods:

• RNA interference (RNAi) was used to inhibit IFNAR1/2, IFN regulatory factor 9, and BID.
• Gene and protein expression of TRAIL and Fas ligand were analyzed.
• Cell viability, mitochondrial membrane potential (ΔΨm), and apoptosis signaling (caspase 8) were assessed.
• BID overexpression was used in IFN-α-resistant lung carcinoma cells.

Main Results:

• IFNAR1/2 and IFN regulatory factor 9 RNAi inhibited TRAIL gene expression and subsequent cell viability reduction induced by IFN-α.
• IFN-α upregulated TRAIL protein levels, and TRAIL, but not Fas ligand, inhibited OVCAR3 cell viability.
• TRAIL signaling involved caspase 8 and BID, as inhibiting these restored cell viability and prevented mitochondrial dysfunction.
• BID overexpression inhibited cell viability in both IFN-α-sensitive and resistant cancer cells treated with IFN-α or TRAIL.

Conclusions:

• BH3 interacting domain death agonist (BID) is crucial for IFN-α-regulated cell viability, mediating mitochondria-dependent apoptosis.
• The IFN-α-induced TRAIL pathway, involving BID, is a potential therapeutic target for IFN-α-resistant tumors.
• Understanding this pathway offers insights for developing novel cancer therapies.