ON-123300 is a potent and multi-targeted kinase inhibitor with potential application for brain tumor chemotherapy. ON123300 strongly inhibits Ark5 and CDK4, as well as growth factor receptor tyrosine kinases such as β-type platelet-derived growth factor receptor (PDGFRβ). ON123300 inhibited U87 glioma cell proliferation and reduced phosphorylation of Akt, yet it also unexpectedly induced Erk activation, both in a dose- and time-dependent manner that subsequently was attributed to relieving Akt-mediated C-Raf S259 inactivation and activating a p70S6K-initiated PI3K-negative feedback loop. ON123300 demonstrated high brain and brain tumor accumulation and favorable pharmacokinetic characteristics.

TIC10 (TIC10 isomer or ONC201 isomer) is a potent, orally active, and stable small molecule and is an efficacious antitumor therapeutic agent that acts on tumor cells and their microenvironment to enhance the concentrations of the endogenous tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). The isomeric structure of TIC10/ONC201 is critical to its activity: anti-cancer activity is associated with the angular structure and not the linear TIC10 isomer. TIC10 transcriptionally induces a sustained up-regulation TRAIL in tumors and normal cells in a p53-independent manner. TIC10 inactivates kinases Akt and extracellular signal-regulated kinase (ERK), leading to the translocation of Foxo3a into the nucleus, where it binds to the TRAIL promoter to up-regulate gene transcription. TIC10 crosses the blood-brain barrier. TIC10 treatment caused tumor regression in the HCT116 p53−/− xenograft, RKO human colon cancer xenograft–bearing mice and human triple-negative breast cancer xenografts and significantly prolonged the survival of Eμ-myc transgenic mice, which spontaneously develop metastatic lymphoma from weeks 9 to 12 of age by 4 weeks.