A Jnk-Rho-Actin remodeling positive feedback network directs Src-driven invasion

Area of Science:

• Molecular Biology
• Cell Biology
• Cancer Research

Background:

• Tumor cell invasion involves cytoskeletal dynamics orchestrated by signaling pathways like c-Jun N-terminal kinase (Jnk) and RhoGTPases.
• Actin remodeling proteins (ARPs) are crucial for cytoskeletal changes during cell migration.
• Src kinase is a significant factor in tumor aggression, metastasis, and patient mortality.

Purpose of the Study:

• To elucidate the mechanisms by which Src regulates actin dynamics and promotes invasive cell migration.
• To identify key mediators of invasion in a Drosophila model.

Main Methods:

• A genetic modifier screen was conducted in a Drosophila model of tumor cell invasion.
• The roles of identified genes in mediating invasion, oncogenic signaling, and pathway activation were investigated.

Main Results:

• Nine genes associated with actin dynamics were identified as mediators of invasion.
• Actin remodeling proteins (ARPs) were found to be essential for Src-driven oncogenic effects, including Mmp1 expression and apoptosis initiation.
• ARPs were identified as regulators of Jnk pathway activity, with both Src and Rho1 activating Jnk in an ARP-dependent manner during invasion.

Conclusions:

• Actin remodeling proteins (ARPs) are not merely downstream executors of oncogenic signaling.
• ARPs are integral components of a positive feedback network involving canonical oncogenic pathways that promote tumor invasion.
• These findings offer new insights into the complex interplay between cytoskeletal dynamics and cancer progression.