miR-28-5p promotes chromosomal instability in VHL-associated cancers by inhibiting Mad2 translation

Area of Science:

• Molecular Biology
• Oncology
• Genetics

Background:

• Chromosomal instability is a hallmark of cancer, often driven by dysregulated mitotic checkpoint proteins like Mad2.
• The von Hippel-Lindau (VHL) tumor suppressor gene is frequently inactivated in clear cell renal cell carcinoma (ccRCC).

Purpose of the Study:

• To elucidate a novel regulatory mechanism for Mad2 expression.
• To investigate the role of microRNA-28-5p (miR-28-5p) in Mad2 regulation and chromosomal stability.
• To determine the link between VHL inactivation, miR-28-5p, and ccRCC pathogenesis.

Main Methods:

• Investigated miR-28-5p-mediated inhibition of Mad2 translation.
• Utilized VHL-positive and VHL-negative cancer cell lines.
• Employed a mouse model of renal injury with kidney-specific pVHL ablation.
• Conducted bioinformatic analyses on human ccRCC patient data.

Main Results:

• Enhanced miR-28-5p expression in VHL-positive cells reduced Mad2 levels, leading to checkpoint weakness and chromosomal instability.
• Inhibition of miR-28-5p in VHL-negative cells restored Mad2 levels, mitotic checkpoint function, and chromosomal stability.
• Genetic inhibition of miR-28-5p reversed chromosome missegregation and aneuploidy in a VHL-deficient mouse model.
• Human ccRCC data showed an association between VHL loss, increased miR-28-5p, and chromosomal instability.

Conclusions:

• miR-28-5p is a critical regulator of Mad2 translation and mitotic checkpoint function.
• The VHL/miR-28-5p axis represents a key mediator of chromosomal instability in VHL-associated cancers.
• Targeting miR-28-5p offers a potential microRNA-based therapeutic strategy for VHL-associated cancers.