Purpose: This study aims to elucidate the biological behavior of Neuritin abnormal expression in pulmonary vascular endothelial cells (VECs) of non-small cell lung cancer (NSCLC), and explore its possible underlying mechanisms.
Patients and methods: Primary NSCLC-VECs were isolated from 10 cancer tissues from NSCLC patients, purified and identified by CD34 and Factor VIII staining. Real-time PCR and Western-blot were adopted for detecting the expression levels of Neuritin, Notch1, and VEGFR in NSCLC-VECs and HPMECs. Neuritin-overexpression, Neuritin-knockdown NSCLC-VECs and HPMECs were constructed by transfection of pcDNA3, 1-Neuritin vector, and pBS/U6-Neuritin siRNA. Changes in cell proliferation, migration, cell cycle, and apoptosis were determined by using the MTT assay, scratch assay, transwell migration assay, and flow cytometry, respectively. Post-transfection changes in cell morphology were examined by scanning electron microscopy.
Results: The expression of Neuritin in NSCLC-VECs was significantly higher compared to that in HPMECs (p<0.01). Overexpression of Neuritin increased the expression of VEGFR while it reduced the expression of Notch1 (p<0.01); it also promoted cell proliferation, scratch healing, and in vitro migration (p<0.05) in HPMECs and NSCLC-VECs cells. Additionally, overexpression of Neuritin stimulated cell cycle progression and inhibited apoptosis in HPMECs and NSCLC-VECs (p<0.001). Under electron microscope, the pseudopodium of cell surface was obvious, indicating that the intercellular adhesion was upregulated. However, knockdown of Neuritin in HPMECs and NSCLC-VECs played exactly the opposite roles.
Conclusion: Neuritin was key in the progression of NSCLC through its biological activities, including anti-apoptosis, promoting VEC proliferation, migration, and cell cycle progression. Neuritin may affect its biological activity by positively regulating VEGFR expression and negatively regulating Notch1 signaling. Neuritin may serve as a potential biomarker for NSCLC.
Keywords: neuritin, non-small cell lung cancer, Notch1, VEGF