ABSTRACT
The nuclear transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) plays a crucial role in maintaining cellular redox homeostasis. The aberrant NRF2 signaling confers enhanced antioxidant capacity, which is linked to tumor progression and therapeutic resistance. The current study investigates the biological effects and molecular mechanism of tribbles homolog 3 (TRIB3), a stress-induced protein, in regulating cell survival and apoptosis in lung cancer. This study first performed the RNA sequencing data analysis with 576 lung adenocarcinoma patients from the cancer genome atlas (TCGA) database. The NRF2- antioxidant response element (ARE) signature was enriched in patients with high TRIB3 expression. Dual-luciferase reporter assay and real-time quantitative polymerase chain reaction (PCR) were used to confirm the effect of TRIB3 on the kelch-like ECH-associated protein-1 (KEAP1)-NRF2 pathway. Abrogation of TRIB3 impaired NRF2 transcriptional activity and reduced the expression of its target genes. Moreover, TRIB3 enhanced NRF2 stability via blocking KEAP1-NRF2 interaction. TRIB3-depletion promoted reactive oxygen species (ROS) production, restrained cell proliferation, and enhanced carboplatin-induced apoptosis. In addition, NRF2 overexpression recovered the tumor inhibition effect of TRIB3-depletion. Consistently, TRIB3 failed to modulate apoptosis in NRF2 depletion cells. In summary, this study shows that TRIB3 inhibits the KEAP1-NRF2 interaction and upregulates the transcriptional activity of NRF2, thereby promoting lung cancer cell proliferation and reducing the sensitivity to chemotherapy. Targeting the TRIB3-NRF2 signal axis may become a new strategy for ROS homeostasis and lung cancer treatment.