QKI-6 inhibits bladder cancer malignant behaviours through down-regulating E2F3 and NF-κB signalling

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Quaking homolog (QKI) is an RNA-binding protein with known tumor suppressor activity in various cancers.
• QKI interacts with the 3'-untranslated region (3'-UTR) of gene transcripts via its STAR domain.
• The specific role and molecular mechanisms of QKI-6 in bladder cancer remain largely unexplored.

Purpose of the Study:

• To investigate the association between QKI-6 expression and clinicopathological features and survival in bladder cancer patients.
• To elucidate the underlying molecular mechanisms by which QKI-6 influences bladder cancer progression.
• To explore the regulatory network involving QKI-6, E2F3, and NF-κB signaling in bladder cancer.

Main Methods:

• Immunohistochemistry was performed on 223 bladder cancer tissues to assess QKI-6 expression.
• In vitro and in vivo assays using bladder cancer cell lines and nude mice were conducted following QKI-6 overexpression or knockdown.
• Molecular mechanisms were investigated through analysis of gene expression, protein interactions, and signaling pathway activity.

Main Results:

• QKI-6 down-regulation correlated with advanced tumor TNM stages and poorer patient overall survival.
• QKI-6 overexpression inhibited bladder cancer cell proliferation, invasion, and xenograft growth, while inducing apoptosis and cell cycle arrest.
• QKI-6 directly suppressed E2F3 expression by binding to its 3'-UTR, and negatively regulated NF-κB signaling, forming a feedback loop with E2F3.

Conclusions:

• QKI-6 functions as a tumor suppressor in bladder cancer.
• Down-regulation of QKI-6 contributes to the development and progression of bladder cancer.
• QKI-6 exerts its tumor-suppressive effects through inhibition of E2F3 and NF-κB signaling pathways.