Open Access

ARTICLE

CLDN9 Levels Influence the Biological Activities of Cells in Gastric Cancer

Jin Liu^1,2, Xiu Zhang¹, Xiao Hu², Gaofeng Yuan², Kai Chen^1,*

1 Department of Oncology, The First Affiliated Hospital of Soochow University, Suzhou, 215000, China
2 Department of Oncology, Suqian First Hospital, Suqian, 223800, China

* Corresponding Author: Kai Chen. Email:

BIOCELL 2025, 49(4), 665-680. https://doi.org/10.32604/biocell.2025.063296

Received 10 January 2025; Accepted 08 April 2025; Issue published 30 April 2025

Abstract

Objective: This study examines the significance and functions of CLDN9 in gastric cancer (GC), intending to identify novel targets for diagnosis and treatment. Methods: CLDN9 expression in GC tissues and cell lines was investigated in TCGA data, with analysis with Western blotting, qRT-PCR, and immunohistochemical analyses. Correlations between clinicopathological characteristics, progression-free survival (PFS), and overall survival (OS) were assessed with Cox regression. The effect of CLDN9 knockdown/overexpression on tumorigenic functions (proliferation, migration, and invasion) was assessed using CCK-8, colony formation, and Transwell assays. Tumor-bearing assays were performed to verify the impact of CLDN9 knockdown on the in vivo proliferation of GC cells. Results: Analysis of TCGA data, qRT-PCR, Western blotting, and immunohistochemistry indicated significantly elevated levels of CLDN9 in GC tissues and cell lines (p < 0.01). Compared to the group with high CLDN9 expression, PFS and OS were markedly longer in cases with low CLDN9 levels (p < 0.05). Multivariate regression indicated that CLDN9 levels were independently predictive of GC prognosis. CCK-8, Transwell, and colony formation tests showed that CLDN9 overexpression promoted GC cell proliferation, clonogenicity, and migratory/invasive capabilities, but CLDN9 knockdown markedly reduced these features. Experiments involving tumor-bearing models demonstrated that the suppression of CLDN9 inhibited the in vivo growth of GC cells. Conclusion: In conclusion, this study’s findings suggested that CLDN9 might be a valuable therapeutic target or diagnostic biomarker for GC.

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Keywords

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