Mutants TP53 p.R273H and p.R273C but not p.R273G Enhance Cancer Cell Malignancy

MutationofthetumorsuppressorTP53gene occurs in greater than half of all human cancers. In ad- dition to loss of tumor suppressor function of wild-type TP53, gain-of-function mutations endow cancer cells with more malignant properties. R273 is a mutation hotspot with the p.R273H, p.R273C, and p.R273G variants oc- curring most commonly in patient samples. To better un- derstand the consequences of these R273 mutations, we constructed cancer cell lines expressing TP53 p.R273H, p.R273C, or p.R273G and explored their characteris- tics. We found that p.R273H and p.R273C, but not p.R273G, enhanced proliferation, invasion, and drug re- sistance in vitro. Furthermore, breast cancer susceptibility protein 1 was upregulated by mutant TP53 p.R273H and p.R273C in response to DNA damage and repair. Tran- scriptional analysis of the TP53-R273 mutants by RNA- seq confirmed that the apoptosis pathway was less active in p.R273H and p.R273C, compared with R273G. Molec- ular dynamics simulation further revealed that TP53- R273G binds more tightly to DNA than TP53-R273H or TP53-R273C. These findings indicate that mutation of TP53 at a single codon has different effects, and likely clinical implications. p.R273H and p.R273C lead to a more aggressive phenotype than p.R273G. These findings may contribute to future diagnosis and therapy in TP53 mutant cancers.