FoxM1-Retinoblastoma Interaction Induces Tumor Microenvironment That Drives Metastasis

A mouse strain expressing an Rb-binding deficient mutant of FoxM1, FoxM1 DD, develops PyMT-driven mammary tumors that are deficient in metastasis. Single-cell RNA-Seq analyses revealed altered tumor microenvironment (TME). Unlike the FoxM1 +/+ tumors, the FoxM1 DD/DD tumors lack tumor-infiltrating cells, resulting from a deficiency in the tumor cell-populations that express factors necessary for their recruitment. Furthermore, FoxM1 DD/DD tumors contain fewer mammary cancer stem/progenitor cells, but more differentiated tumor cells. FoxM1 +/+ PyMT-driven mammary tumors were compared to FoxM1 DD/DD PyMT-driven mammary tumors by single cell RNA-seq (Drop-seq)