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Updated: Sep 27, 2025
Pre-clinical Evaluation of Tyrosine Kinase Inhibitors for Treatment of Acute Leukemia
Published on: September 18, 2013
Validation of a small molecule inhibitor of PDE6D-RAS interaction with favorable anti-leukemic effects
Sara Canovas Nunes1, Serena De Vita1, Andrew Anighoro2
1Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
Abstract:
RAS mutations prevalent in high-risk leukemia have been linked to relapse and chemotherapy resistance. Efforts to directly target RAS proteins have been largely unsuccessful. However, since RAS-mediated transformation is dependent on signaling through the RAS-related C3 botulinum toxin substrate (RAC) small GTPase, we hypothesized that targeting RAC may be an effective therapeutic approach in RAS mutated tumors. Here we describe multiple small molecules capable of inhibiting RAC activation in acute lymphoblastic leukemia cell lines. One of these, DW0254, also demonstrates promising anti-leukemic activity in RAS-mutated cells. Using chemical proteomics and biophysical methods, we identified the hydrophobic pocket of phosphodiester 6 subunit delta (PDE6D), a known RAS chaperone, as a target for this compound. Inhibition of RAS localization to the plasma membrane upon DW0254 treatment is associated with RAC inhibition through a phosphatidylinositol-3-kinase/AKT-dependent mechanism. Our findings provide new insights into the importance of PDE6D-mediated transport for RAS-dependent RAC activation and leukemic cell survival.
Insights
Targeting RAS-related C3 botulinum toxin substrate (RAC) shows promise for treating RAS-mutated leukemia. A novel compound, DW0254, inhibits RAC activation by targeting the PDE6D chaperone, leading to anti-leukemic effects.
Area of Science:
- Oncology
- Molecular Biology
- Drug Discovery
Background:
- RAS mutations are common in high-risk leukemia, leading to relapse and resistance to chemotherapy.
- Directly targeting RAS proteins has proven challenging.
- RAS-mediated transformation relies on signaling through the RAS-related C3 botulinum toxin substrate (RAC) small GTPase.
Purpose of the Study:
- To investigate targeting RAC as a therapeutic strategy for RAS-mutated tumors.
- To identify small molecules that inhibit RAC activation.
- To explore the anti-leukemic activity of novel compounds in RAS-mutated leukemia.
Main Methods:
- Screening of small molecules for RAC activation inhibition in acute lymphoblastic leukemia cell lines.
- Chemical proteomics and biophysical methods to identify compound targets.
- Assessment of compound effects on RAS localization and RAC inhibition.
- Investigation of downstream signaling pathways, including phosphatidylinositol-3-kinase/AKT.
Main Results:
- Multiple small molecules were identified that inhibit RAC activation.
- The compound DW0254 demonstrated significant anti-leukemic activity in RAS-mutated cells.
- DW0254 targets the hydrophobic pocket of phosphodiester 6 subunit delta (PDE6D), a RAS chaperone.
- DW0254 treatment inhibited RAS plasma membrane localization, leading to RAC inhibition via a PI3K/AKT-dependent pathway.
Conclusions:
- Targeting PDE6D-mediated RAS transport is a viable strategy for inhibiting RAC activation.
- DW0254 shows therapeutic potential for RAS-mutated leukemia by disrupting RAS-dependent signaling.
- These findings offer new insights into leukemic cell survival mechanisms and potential drug targets.
