FOLH1 and prostate cancer: DS-7423-dependent changes in PSMA levels were partially abrogated by treatment with lapatinib or VCC185369 (28), an additional inhibitor of HER2 kinase activity (Fig. 3), demonstrating the involvement of HER2 signaling in PSMA upregulation upon PI3K/mTOR inhibition in PTEN-wt prostate cancer cell lines.