Cancer-Associated Fibroblasts Accelerate Malignant Progression of Non-Small Cell Lung Cancer via Connexin 43-Formed Unidirectional Gap Junctional Intercellular Communication

• Published in: Cellular physiology and biochemistry Vol. 51; no. 1; pp. 315 - 336
• Main Authors: Luo, Min, Luo, Yanmei, Mao, Naiquan, Huang, Guolin, Teng, Cuifang, Wang, Hanlin, Wu, Junwei, Liao, Xiaoli, Yang, Jie
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01-01-2018; Cell Physiol Biochem Press GmbH & Co KG
• Subjects: Adenosine Triphosphate - metabolism; Antibiotics; Cadherins - metabolism; Cancer-associated fibroblasts; Cancer-Associated Fibroblasts - cytology; Cancer-Associated Fibroblasts - metabolism; Carcinoma, Non-Small-Cell Lung - metabolism; Carcinoma, Non-Small-Cell Lung - mortality; Carcinoma, Non-Small-Cell Lung - pathology; Cell cycle; Cell Line, Tumor; Cell Movement; Collagen; Communication; Connexin 43; Connexin 43 - antagonists & inhibitors; Connexin 43 - genetics; Connexin 43 - metabolism; Cooperation; Epithelial-Mesenchymal Transition; Female; Fibroblasts; Gap Junctions - metabolism; Humans; Immunoglobulins; Kaplan-Meier Estimate; Kinases; Lung cancer; Lung Neoplasms - metabolism; Lung Neoplasms - mortality; Lung Neoplasms - pathology; Male; Malignant progression; Medical prognosis; Metabolic coupling; Metabolism; Metabolites; Metastasis; Middle Aged; Non-small cell lung cancer; Original Paper; Phosphatidylinositol 3-Kinases - antagonists & inhibitors; Phosphatidylinositol 3-Kinases - metabolism; Prostate cancer; Proto-Oncogene Proteins c-akt - antagonists & inhibitors; Proto-Oncogene Proteins c-akt - metabolism; RNA Interference; RNA, Small Interfering - metabolism; Signal Transduction; Stem cells; Unidirectional gap junctional intercellular communication; United States > US; China; Cancer-associated fibroblasts; Metabolic coupling; Connexin 43; Unidirectional gap junctional intercellular communication; Malignant progression; Non-small cell lung cancer
• ISSN: 1015-8987; 1421-9778
• DOI: 10.1159/000495232

Background/Aims: Gap junctions, which are assembled by connexins, can directly connect the cytoplasm of adjacent cells and enable gap junctional intercellular communication (GJIC) as well as metabolic coupling between neighboring cells. Here, we investigated the role of connexin 43 (Cx43) and its derived GJIC in the interplay between non-small cell lung cancer (NSCLC) cells and cancer-associated fibroblasts (CAFs). Methods: CAFs and NSCLC cells were co-cultured with direct contact and separated using flow cytometry. Glucose uptake, lactate production, and the expression and activity of PKM-2 and LDH-A in sorted CAFs were measured by a colorimetric assay, western blotting, and enzyme-linked immunosorbent assay (ELISA). Meanwhile, E-cadherin and N-cadherin expression and the migration and invasion of sorted NSCLC cells were detected by western blotting, wound width, and Transwell assays. Pyruvate, acetyl-CoA, and citric acid levels, ATP levels, and LDH-B and α-KG activity in sorted NSCLC cells were determined by a colorimetric or fluorometric assay and ELISA, respectively. Functional GJIC between cells and the subcellular location of connexins were detected by a “Parachute” assay and immunofluorescence. Levels of α-SMA, Cx43, and LDH-B in tissue from patients with NSCLC were determined by immunohistochemistry. Results: Cx43 accumulated in the plasma membrane, which favored the assembly of asymmetric unidirectional GJIC from CAFs to NSCLC cells. CAFs underwent increased aerobic glycolysis and promoted the epithelial-mesenchymal transition, migration, and invasion of NSCLC cells. In contrast, NSCLC cells experienced enhanced oxidative phosphorylation upon CAF stimulation, with an increase in ATP generation and thereby activation of the PI3K/Akt and MAPK/ERK pathways. Metabolic coupling between CAFs and NSCLC cells was under the strict control of Cx43-formed unidirectional GJIC. Patients with high tri-expression of α-SMA, Cx43, and LDH-B had the shortest overall survival and relapse-free survival compared with those with individual overexpression or high bi-expression. Conclusion: Cx43-formed unidirectional GJIC plays a critical role in mediating close metabolic cooperation between CAFs and NSCLC cells to support the malignant progression of NSCLC.