Graduation Date

Spring 5-4-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Programs

Biochemistry & Molecular Biology

First Advisor

Dr. Imayavaramban Lakshmanan

Abstract

Lung cancer stands as a leading cause of cancer-related mortality worldwide, with small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) comprising its primary categories. NSCLC, representing nearly 85% of cases, exhibits a 5-year survival rate of less than 21%. Among NSCLC subtypes, lung adenocarcinoma (LUAD) prevails as the most common, followed by squamous cell carcinoma and large cell carcinoma. Gap junctions are crucial for intercellular communication and cellular homeostasis maintenance, demonstrate altered expression patterns in various diseases, including cancer. Gap junction beta 3 (GJB3 or Connexin31) exhibits significant expression in both preclinical and clinical LUAD samples, prompting investigation into its role in LUAD pathobiology. This study utilized genetically engineered LUAD models and patient samples for immunohistochemical and bioinformatic analyses to unravel the clinical relevance of GJB3. Our findings unveiled GJB3 among the top upregulated molecules in LUAD based on RNA sequence data from genetically engineered mouse (GEM) models. Immunohistochemical analysis corroborated significant GJB3 overexpression in LUAD compared to normal lung tissues. Employing GJB3 shRNA constructs, we stably knocked down endogenous GJB3 expression in H1437 and mouse syngeneic cell line KP2075. Subsequent assessments, including dye studies, mass spectrometry (MS), cell cycle analysis (FACS), connexon formation assays, and colony formation assays, were conducted on GJB3 knockdown (KD) and control cells. Our results unveiled, reduced gap junction intercellular communication, decreased proliferation, connexon formation, colony formation, and migration, along with impaired wound healing abilities in GJB3 KD cells. Proteomic analysis further disclosed altered expression of proteins associated with ABHD12, CMAS, death receptor-mediated signaling pathways, and VEGFA/VEGFR2 signaling in GJB3 KD cells. This study underscores the association of altered GJB3 expression with the aggressive behavior of LUAD cells, influencing critical pathways such as VEGFA/VEGFR2 signaling and death receptor signaling pathways. Further elucidation of the specific molecular mechanisms modulated by GJB3 may unveil promising therapeutic avenues targeting GJB3 in the context of lung adenocarcinoma.

Comments

2024 Copyright, the authors

Download

Available for download on Sunday, April 26, 2026

Share

COinS