DIAPH3 governs the cellular transition to the amoeboid tumour phenotype

Area of Science:

• Oncology
• Cell Biology
• Molecular Biology

Background:

• Metastasis remains a major challenge in cancer therapy, with underlying cellular signaling networks poorly understood.
• Understanding the molecular mechanisms that control cancer cell migration and invasion is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the role of Diaphanous-related formin-3 (DIAPH3) as a regulator of metastasis in human carcinomas.
• To elucidate the molecular mechanisms by which DIAPH3 influences cancer cell behavior and signaling pathways.

Main Methods:

• DIAPH3 function was assessed through gene silencing in human carcinoma cell lines.
• Effects on cell behavior, including motility, invasion, and signaling pathways (EGFR/MEK/ERK), were analyzed.
• Tumor metastasis was evaluated in mouse models.
• DIAPH3 expression levels were correlated with clinical data from human tumors.

Main Results:

• DIAPH3 silencing destabilized microtubules, impaired endocytic trafficking, and led to EGFR accumulation and signaling hyperactivation.
• Loss of DIAPH3 induced amoeboid cell properties, increased invasion, and promoted metastasis in vivo.
• Down-regulation of DIAPH3 in human tumors correlated with aggressive disease and metastasis.
• DIAPH3-silenced cells showed sensitivity to MEK inhibitors but reduced sensitivity to EGFR inhibitors.

Conclusions:

• DIAPH3 acts as a non-canonical regulator that restrains amoeboid cell transition and metastasis in multiple cancer types.
• DIAPH3 down-regulation is associated with metastatic potential and aggressive cancer phenotypes.
• Chromosomal deletions at the DIAPH3 locus may serve as a prognostic marker, and DIAPH3 status could inform therapeutic strategies, particularly regarding MEK inhibition.