FOXO1 and pulmonary arterial hypertension: The transduction with a non-phosphorylatable, constitutively active adenovirus carrying FoxO1 affected proliferation and apoptosis of both control human PASMCs and rat PAH PASMCs, signifying that constitutive activation of FoxO1 inhibits the hyperproliferative and apoptosis-resistant phenotype of PASMCs in vitro [55].