Rigosertib as a selective anti-tumor agent can ameliorate multiple dysregulated signaling transduction pathways in...

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis and a high risk of transformation to acute myeloid leukemia.
• Rigosertib has shown therapeutic potential in clinical trials for high-risk MDS, but its precise mechanisms of action require further elucidation.
• Understanding the molecular pathways dysregulated in MDS is crucial for developing targeted therapies.

Purpose of the Study:

• To characterize the molecular mechanisms underlying the therapeutic activity of rigosertib in myelodysplastic syndrome (MDS).
• To investigate the effects of rigosertib on malignant CD34+ cells versus normal CD34+ cells.
• To identify the specific signaling pathways modulated by rigosertib in different grades of MDS.

Main Methods:

• Cell cycle analysis and proliferation assays on CD34+ cells from MDS patients and healthy donors.
• Western blotting and bioinformatics analysis to assess signaling pathway activation (P53, Akt-PI3K, Jak-STAT, Wnt, MAPK, SAPK/JNK).
• Receptor tyrosine kinase phosphorylation array to evaluate the impact of rigosertib on specific kinases (RET, PDGFR-β, Tie2, VEGFR2).

Main Results:

• Rigosertib induced apoptosis, cell cycle arrest at G2/M phase, and inhibited proliferation of MDS CD34+ cells, with minimal effects on normal cells.
• Rigosertib activated the P53 signaling pathway and differentially modulated other pathways: inhibiting Akt-PI3K and Wnt, while activating SAPK/JNK in high-grade MDS.
• Rigosertib increased RET and PDGFR-β activation and decreased Tie2 and VEGFR2 activation in MDS cells.

Conclusions:

• Rigosertib demonstrates selective anti-tumor activity against high-grade MDS by targeting multiple dysregulated signaling pathways.
• The drug's ability to induce apoptosis and inhibit proliferation, coupled with its specific pathway modulation, highlights its potential as a targeted therapy for MDS.
• Rigosertib represents a promising agent for ameliorating aberrant signaling in high-grade MDS.