Previously, we reported that suppression of ceramide glycosylation restored wild-type p53 protein and tumor suppressing function in cancer cells heterozygously carrying p53 R273H, a hot-spot missense mutation; however, the mechanisms underlying the control of mutant protein expression remain elusive.
Inhibition of glucosylceramide synthase with d-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) sensitized p53-R273H cancer cells and tumor xenografts to doxorubicin treatments.
To investigate the DN effect on tumor migration and invasion, we generated cells that stably co-expressed wild-type (wt) and R273H DN mutant TP53 (273H cells), and wt and R213Q recessive mutant TP53 (213Q cells), by transfection in endometrial cancer cells HHUA that expressed wt p53.
In contrast to the endometrioid-type tumor, all 3 mutations in 5 serous-type tumors (R273H, 9-bp deletion in codons 240-243, and R248W) showed dominant-negative capacity and presented in a homozygous state in the tumors, indicating a complete functional inactivation.