CTX1 is a small molecule activator of p53.

CTX1 can induce p53 protein levels in the p53 mutant cell line, HT29 and it also induces significant p53-dependent cell death preferentially in HdmX-expressing cells as compared to cells in which p53 is inactivated by Hdm2 overexpression or p53 is knocked down using p53 targeting shRNA. It is also found that CTX1 shows potent activity (LD50 ~1 μM) as a single agent on primary AML patient samples in a similar fashion to AML cell lines. After CTX1(16 h) treatment in HCT116 p53-wild-type cells, there is a decrease in S phase from 23% to 3% while HCT116 p53-null cells exhibit a reduction in S phase from 34% to 28%. The combination of low doses of CTX1 and nutlin-3 leads to a significant enhancement of apoptosis in p53-wildtype, but not p53-null cells.

Mice treated with CTX1 alone or in combination with nutlin-3 has a significantly increased survival time (p<0.0001). In this model system, CTX1 even as a single agent significantly enhances the survival of mice.