MiR-135b promotes HCC tumorigenesis through a positive-feedback loop.

Area of Science:

• Molecular Biology
• Oncology
• Biochemistry

Background:

• The Hippo pathway regulates cell proliferation and apoptosis, and its dysregulation is linked to cancers like hepatocellular carcinoma (HCC).
• Mechanisms maintaining Hippo pathway homeostasis in HCC remain largely unknown.

Purpose of the Study:

• To investigate the role of miR-135b in HCC progression.
• To elucidate the mechanism by which miR-135b affects the Hippo pathway.
• To identify potential biomarkers and therapeutic targets for HCC.

Main Methods:

• Analysis of miR-135b expression in HCC tissues and cell lines.
• In vitro experiments using miR-135b mimics and inhibitors to assess effects on HCC cell proliferation and migration.
• Identification of miR-135b binding sites in MST1 3'-UTR.
• Investigation of the transcriptional regulation of miR-135b by the Hippo pathway.

Main Results:

• miR-135b expression is significantly upregulated in HCC tissues and cell lines.
• Higher miR-135b levels correlate with advanced HCC stages and reduced patient survival.
• miR-135b promotes HCC cell proliferation and migration by inhibiting MST1 expression and thus the Hippo pathway.
• A positive feedback loop involving MST1-YAP-miR-135b was identified, contributing to HCC aggravation.

Conclusions:

• miR-135b acts as an oncogene in HCC progression.
• A novel positive-feedback axis (MST1-YAP-miR-135b) contributes to Hippo pathway dysregulation in HCC.
• miR-135b is a potential prognostic biomarker and therapeutic target for hepatocellular carcinoma.