Our collaborative research team has received a new four-year NIH Multi-PI R01 to investigate how tobacco smoke-induced metabolic reprogramming and PRMT5 lactylation promote fibroblast activation and pulmonary fibrosis. The project will define the molecular mechanisms linking protein lactylation, epigenetic regulation, and fibrotic remodeling and evaluate PRMT5 as a potential therapeutic target.
Our laboratory has received a four-year renewal of its NIH/NHLBI R01 to investigate how phospho-MARCKS regulates macrophage reprogramming in tobacco smoke-driven pulmonary fibrosis. The project will combine mechanistic studies, genetic and pharmacological approaches, precision-cut lung slices, and patient-derived models to evaluate the MARCKS pathway as a potential therapeutic target.
Abstract
Rationale: Cigarette smoking is a major risk factor for lung cancer development and progression; however, the mechanism of how cigarette smoke activates signaling pathways in promoting cancer malignancy remains to be established. Herein, we aimed to determine the contribution of a signaling protein, myristoylated alanine-rich C kinase substrate (MARCKS), in smoke-mediated lung cancer.
Methods: We firstly examined the levels of phosphorylated M ARCKS (phospho-M ARCKS) in smoke-exposed human lung cancer cells and specimens as well as non-human primate airway epithelium. Next, the MARCKS-interactome and its gene networks were identified. We also used genetic and pharmacological approaches to verify the functionality and molecular mechanism of smoke-induced phospho-M ARCKS.
Results: We observed that MARCKS becomes activated in airway epithelium and lung cancer cells in response to cigarette smoke. Functional proteomics revealed MARCKS protein directly binds to NF-κB-activating protein (NKAP). Following MARCKS phosphorylation at ser159 and ser163, the MARCKS-NKAP interaction was inhibited, leading to the activation of NF-κB signaling. In a screen of two cohorts of lung cancer patients, we confirmed that phospho-MARCKS is positively correlated with phospho-NF-κB (phospho-p65), and poor survival. Surprisingly, smoke-induced phospho-MARCKS upregulated the expression of pro-inflammatory cytokines, epithelial–mesenchymal transition, and stem-like properties. Conversely, targeting of MARCKS phosphorylation with MPS peptide, a specific MARCKS phosphorylation inhibitor, suppressed smoke-mediated NF-κB signaling activity, pro-inflammatory cytokines expression, aggressiveness and stemness of lung cancer cells.
Conclusion: Our results suggest that phospho-MARCKS is a novel NF-kB activator in smoke-mediated lung cancer progression and provide a promising molecular model for developing new anticancer strategies.
