Induction of apoptosis by the retinoid inducible growth regulator RIG1 depends on the NC motif in HtTA cervical cancer cells

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Retinoid-inducible gene 1 (RIG1), also known as tazarotene-induced gene 3, regulates cell growth, apoptosis, and differentiation.
• RIG1 belongs to the NC protein family, and its role in cell death pathways is under investigation.
• This study aimed to identify functional domains and critical amino acids responsible for RIG1-mediated apoptosis.

Purpose of the Study:

• To elucidate the functional domains of RIG1 involved in inducing apoptosis.
• To identify specific amino acids within the NC domain critical for RIG1's pro-apoptotic activity.
• To evaluate the therapeutic potential of RIG1-derived peptides as anticancer agents.

Main Methods:

• Utilized enhanced green fluorescence protein (EGFP)-tagged RIG1 variants with deletions and mutations in the NC domain.
• Constructed fusion variants containing only the NC domain of RIG1.
• Synthesized and tested dodecapeptides, including wild-type and mutated RIG1(111-123) sequences, for their effects on cell localization and apoptosis induction in cancer and fibroblast cell lines.

Main Results:

• Deletion of the NC domain significantly reduced RIG1-induced cell death, while the NC domain alone potently induced apoptosis in HtTA cervical cancer cells.
• Mutations within the NC motif (N(112)C(113)) of RIG1 significantly impaired its ability to induce apoptosis.
• The RIG1(111-123) dodecapeptide, particularly the Leu121-mutated variant, induced nuclear localization and significant apoptosis in HtTA and A2058 melanoma cells, but not in normal fibroblasts.

Conclusions:

• The NC domain, and specifically the NC motif, is essential for RIG1's pro-apoptotic function.
• The RIG1(111-123) dodecapeptide demonstrates potent pro-apoptotic activity and warrants further investigation as a potential anticancer therapeutic.