TTK inhibitors SPK17 and SPK17b show 59-176-fold lower IC50 than temozolomide in TMZ-resistant glioblastoma cell lines

The IITGN team screened more than 15 analogs of the prior TTK inhibitor J54. They measured viability, apoptosis markers, and DNA damage in two standard human glioblastoma lines plus LN229-TMZ-R cells generated by chronic temozolomide exposure. SPK17 achieved 50 percent viability reduction at concentrations approximately 176-fold and 85-fold lower than TMZ in LN229 and U87MG cells, respectively; SPK17b showed 81-fold and 59-fold advantages. At 10 micromolar, both compounds generated roughly eight times the apoptotic signal seen with 200 micromolar TMZ in resistant cells.

TTK normally safeguards mitotic fidelity; glioblastoma cells over-rely on it to tolerate genomic instability. Dual inhibition of TTK and DNA-repair pathways may therefore synergize with alkylating agents, a pattern observed in earlier MPS1-inhibitor trials that combined with radiotherapy or PARP inhibitors. The present data extend that logic to TMZ-resistant clones but remain confined to two-dimensional culture without pharmacokinetic or blood-brain-barrier assessment.

Next steps require orthotopic xenograft models to test intracranial efficacy, followed by IND-enabling toxicology. If CNS exposure and therapeutic index prove adequate, a phase-0/1 window-of-opportunity trial could evaluate pharmacodynamic TTK target engagement in recurrent glioblastoma within 24-36 months.