Analysis of Rho GTPase expression in T-ALL identifies RhoU as a target for Notch involved in T-ALL cell migration.

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• NOTCH1 mutations are common in T-cell acute lymphoblastic leukaemia (T-ALL), driving cancer cell survival and proliferation.
• The role of Notch1 in T-ALL cell migration remains largely unexplored.
• Rho GTPases are critical regulators of cell adhesion and migration.

Purpose of the Study:

• To investigate the hypothesis that Notch1 signaling influences T-ALL cell migration.
• To identify specific Rho GTPases involved in T-ALL pathogenesis and their regulation by Notch1.

Main Methods:

• Quantitative PCR was used to analyze Rho GTPase expression in primary T-ALL samples and normal T cells.
• Notch1 signaling was inhibited using a gamma-secretase inhibitor (GSI) or Notch1 RNA interference.
• The effects of Notch1 or RhoU depletion, and GSI treatment on T-ALL cell adhesion, migration, and chemotaxis were assessed.

Main Results:

• Five of 20 human Rho genes were significantly upregulated in T-ALL compared to normal T cells.
• RHOU expression showed a strong correlation with the Notch1 target DELTEX-1.
• Inhibition of Notch1 signaling reduced RhoU expression, while its activation increased RhoU levels.
• Notch1 or RhoU depletion, or GSI treatment, inhibited T-ALL cell adhesion, migration, and chemotaxis.

Conclusions:

• NOTCH1 mutations promote T-ALL cell migration via RhoU upregulation, potentially contributing to leukaemia cell dissemination.
• RhoU represents a potential therapeutic target for inhibiting T-ALL cell migration and spread.