Related Experiment Videos
Functional analysis of leukemia-associated PTPN11 mutations in primary hematopoietic cells
Suzanne Schubbert1, Kenneth Lieuw, Sara L Rowe
1Department of Pediatrics, University of California at San Francisco, 513 Parnassus Ave, HSE 302, San Francisco, CA 94143, USA.
Blood
|March 12, 2005
Summary
Mutations in PTPN11, a gene encoding SHP-2 phosphatase, drive Noonan syndrome and juvenile myelomonocytic leukemia (JMML). Leukemia-associated mutations cause aberrant hematopoietic cell growth, supporting Ras pathway hyperactivity in JMML.
Area of Science:
- Molecular Biology
- Hematology
- Cancer Biology
Background:
- PTPN11 mutations are implicated in Noonan syndrome (NS) and juvenile myelomonocytic leukemia (JMML).
- Somatic PTPN11 mutations in JMML are distinct from germline mutations found in NS.
- SHP-2 phosphatase regulates signaling from growth factor receptors to Ras.
Purpose of the Study:
- To investigate the functional consequences of leukemia-associated PTPN11 mutations in murine hematopoietic cells.
- To compare the effects of JMML-specific SHP-2 mutations with those found in NS.
Main Methods:
- Assessed functional consequences of leukemia-associated PTPN11 mutations in murine hematopoietic cells.
- Expressed E76K SHP-2 protein and analyzed its effects on hematopoietic progenitor cell growth and differentiation.
- Utilized colony-forming unit assays and liquid cultures to evaluate cellular responses.
Main Results:
- E76K SHP-2 expression led to hypersensitive progenitor cell growth in response to GM-CSF and IL-3, dependent on SHP-2 catalytic activity.
- Mutant SHP-2 enhanced immature progenitor growth, perturbed erythroid development, and impaired normal hematopoietic differentiation.
- Leukemia-associated SHP-2 mutations exhibited a more potent phenotype than NS-associated mutations.
Conclusions:
- Aberrant growth in multiple hematopoietic compartments driven by mutant SHP-2 supports a primary role for hyperactive Ras in JMML pathogenesis.
- PTPN11 mutations represent key drivers in the development of JMML.
- SHP-2's role in hematopoietic development is critical, and its dysregulation has significant implications for leukemia.