Disassembly of hemidesmosomes promotes tumorigenesis in PTEN-negative prostate cancer by targeting plectin into focal adhesions

Loss of α6β4-dependent hemidesmosomes has been observed during prostate cancer progression. However, the significance and underlying mechanisms by which aberrant hemidesmosome assembly may modulate tumorigenesis remain elusive. Using an extensive CRISPR/Cas9-mediated genetic engineering approaches in different prostate cancer cell lines combined with in vivo tumorigenesis studies in mice, bone marrow-on-chip assays and bioinformatics, as well as histological analysis of prostate cancer patient cohorts, we demonstrated that simultaneous loss of PTEN and hemidesmosomes induced several tumorigenic properties including proliferation, migration, resistance to anoikis, apoptosis, and drug treatment in vitro, and increased metastatic capacity in vivo. Our studies showed that these effects were driven by activation of EGFR/PI3K/Akt and FAK/Src-pathways and were abolished by plectin downregulation. Therefore, dual loss of PTEN and hemidesmosomes may have diagnostic value helping to stratify prostate cancer patients with high risk for development of aggressive disease and highlight plectin as a potential therapeutic target in prostate cancer.