TTK inhibitor OSU13 promotes immunotherapy responses by activating tumor STING

Area of Science:

• Oncology
• Cancer Biology
• Immunology

Background:

• TTK spindle assembly checkpoint kinase is a promising cancer target.
• Understanding the antitumor mechanisms of TTK inhibitors is crucial for clinical development.

Purpose of the Study:

• To explore the antitumor mechanism of TTK inhibitor OSU13.
• To define a strategy for the clinical development of OSU13.

Main Methods:

• Preclinical study using cancer cell lines, patient-derived organoids, and mouse models.
• Assessed cell cycle arrest, senescence, apoptosis, DNA damage, and cGAS/STING pathway activation.
• Investigated the combination of OSU13 with anti-PD-1 checkpoint blockade.

Main Results:

• OSU13 demonstrated antitumor activity in melanoma, colon, and breast cancers, inducing G2 cell cycle arrest, senescence, and apoptosis.
• OSU13 treatment led to DNA damage and micronuclei formation, activating the cGAS/STING pathway.
• Combination therapy with OSU13 and anti-PD-1 resulted in significant tumor inhibition and improved survival, dependent on STING and CD8+ T cells.

Conclusions:

• OSU13 exhibits potent preclinical antitumor activity through DNA damage and immune pathway activation.
• Combining TTK inhibitors with immunotherapy, particularly in STING-proficient tumors, is a promising strategy for cancer treatment.