Mutant p53 promotes epithelial ovarian cancer by regulating tumor differentiation, metastasis, and responsiveness to steroid hormones
Menée à l'aide d'un modèle murin de tumeur mucineuse de l'ovaire, cette étude met en évidence le rôle joué par un gène TP53 muté dans la progression tumorale
Mutations in the tumor protein p53 (TP53) are the most frequently occurring genetic events in high-grade ovarian cancers, especially the prevalence of the TP53R175H mutant allele. In this study, we investigated the impact of the TP53R175H mutant allele on epithelial ovarian cancer (EOC) in vivo. We used the Pten/KrasG12D mutant mouse strain that develops serous EOC with 100% penetrance to introduce the mutant Trp53R172H allele (homolog for human TP53R175H). We demonstrate that the Trp53R172H mutation promoted EOC, but had differential effects on disease features and progression depending on the presence or absence of the wild-type (WT) TP53 allele. Heterozygous WT/Trp53R172H alleles facilitated invasion into the ovarian stroma, accelerated intraperitoneal metastasis, reduced TP53 transactivation activity, but retained responsiveness to nutlin-3a, an activator of WT TP53. Moreover, high levels of estrogen receptor alpha in these tumors enhanced the growth of both primary and metastatic tumors in response to estradiol. Ovarian tumors homozygous for Trp53R172H mutation were undifferentiated and highly metastatic, exhibited minimal TP53 transactivation activity, and expressed genes with potential regulatory functions in EOC development. Notably, heterozygous WT/Trp53R172H mice also presented mucinous cystadenocarcinomas at 12 weeks of age, recapitulating human mucinous ovarian tumors, which also exhibit heterozygous TP53 mutations (~50-60%) and KRAS mutations. Therefore, we present the first mouse model of mucinous tumor formation from ovarian cells and supporting evidence that mutant TP53 is a key regulator of EOC progression, differentiation, and responsiveness to steroid hormones.