Rigosertib Induces Mitotic Arrest and Apoptosis in RAS-Mutated Rhabdomyosarcoma and Neuroblastoma

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Relapsed pediatric rhabdomyosarcomas (RMS) and neuroblastomas (NBs) have poor prognoses with current therapies.
• Standard treatments like vinca alkaloids have significant toxicities, necessitating novel therapeutic approaches.
• There is a critical need for new treatments for pediatric RMS and NBs.

Purpose of the Study:

• To investigate the efficacy of the small-molecule rigosertib against pediatric rhabdomyosarcoma (RMS) and neuroblastoma (NB) cell lines.
• To elucidate the mechanism of action of rigosertib in these cancer models.
• To explore potential combination therapies involving rigosertib.

Main Methods:

• Treatment of RMS and NB cell lines with rigosertib.
• Analysis of cell cycle progression and cell death.
• Investigation of the role of RAS signaling and mitotic spindle assembly.
• Evaluation of combination therapy with trametinib in an RMS cell line.
• Assessment of rigosertib efficacy in an RMS xenograft model.

Main Results:

• Rigosertib inhibited the growth of RMS and NB cell lines by inducing mitotic arrest and cell death.
• Rigosertib's primary mechanism involves interference with mitotic spindle assembly, similar to vinca alkaloids.
• Rigosertib did not induce cell death via RAS pathway inhibition in RAS-mutated cells.
• Combination of rigosertib and trametinib showed synergistic growth inhibition in an RMS cell line.
• Rigosertib treatment delayed tumor growth and prolonged survival in an RMS xenograft model.

Conclusions:

• Rigosertib demonstrates significant anti-tumor activity against pediatric RMS and NB cell lines.
• The drug's mechanism of action is linked to mitotic spindle disruption.
• Rigosertib holds potential as a novel therapeutic agent for RMS, with combination strategies offering new avenues for treatment.