The requirement of phosphoenolpyruvate carboxykinase 1 for angiogenesis in vitro and in vivo

Abstract

We here examined the potential biological function of phosphoenolpyruvate carboxykinase 1 (PCK1) in angiogenesis. shRNA- or CRISPR-Cas9–induced PCK1 depletion potently inhibited endothelial cell proliferation, migration, sprouting, and tube formation, whereas ectopic PCK1 overexpression exerted opposite activity. In HUVECs, Gα i3 expression and Akt activation were decreased following PCK1 depletion, but were augmented by ectopic PCK1 overexpression. In vivo, retinal expression of PCK1 gradually increased from postnatal day 1 (P1) to P5. The intravitreous injection of endothelial-specific PCK1 shRNA adenovirus at P1 potently inhibited the radial extension of vascular plexus at P5. Conditional endothelial knockdown of PCK1 in adult mouse retina increased vascular leakage and the number of acellular capillaries while decreasing the number of RGCs in murine retinas. In diabetic retinopathy patients, PCK1 mRNA and protein levels were up-regulated in retinal tissues. Together, PCK1 is essential for angiogenesis possibly by mediating Gα i3 expression and Akt activation.

Identification of Gαi3 as a novel molecular therapeutic target of cervical cancer

“…An early study using luciferase reporter assay and chromatin Immunoprecipitation (ChIP) demonstrated that the transcription factor GATA4 can directly bind to the promoter region of Gαi3 and regulate its transcriptional activity and expression [33]. The very recent study of our group has shown that GATA4 is an important transcription factor of Gαi3 in endothelial cells [28]. We further discovered that phosphoenolpyruvate carboxykinase 1 (PCK1) associated with phosphorylated GATA4, promoting Gαi3 transcription and expression in endothelial cells [28].…”

“…The very recent study of our group has shown that GATA4 is an important transcription factor of Gαi3 in endothelial cells [28]. We further discovered that phosphoenolpyruvate carboxykinase 1 (PCK1) associated with phosphorylated GATA4, promoting Gαi3 transcription and expression in endothelial cells [28]. It will then lead to increased Akt-mTOR activation and pro-angiogenesis response [28].…”

“…We further discovered that phosphoenolpyruvate carboxykinase 1 (PCK1) associated with phosphorylated GATA4, promoting Gαi3 transcription and expression in endothelial cells [28]. It will then lead to increased Akt-mTOR activation and pro-angiogenesis response [28]. Here in cervical cancer cells, Gαi3 was decreased following GATA4 shRNA, but was upregulated following GATA4 overexpression.…”

“…Our group [28] and others have supported that GATA4 is one important transcription factor for Gαi3 [33]. We therefore analyzed whether GATA4 was the primary mechanism of Gαi3 overexpression in cervical cancer.…”

“…The lentiviral constructs encoding the GATA4 shRNA or the GATA4-expressing sequence, as well as their relative control constructs, were reported in our previous study 28 . The constructs were individually and stably transduced to the primary human cervical cancer cells.…”