AKT1 and pulmonary arterial hypertension: Phosphorylation of CREB was inhibited with a concomitant decrease of PTEN, whereas a naturally occurring prostanoid prostaglandin E1 (PGE1) treatment could restore PTEN expression by elevating the phosphorylated levels of CREB indicating that PGE1 recruiting CREB/PTEN to inhibit PI3K/Akt signaling pathway can prevent the progression of PAH [124].