Better understanding of phosphoinositide 3-kinase (PI3K) pathways in vasculature: Towards precision therapy targeting angiogenesis and tumor blood supply


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Abstract

The intracellular PI3K-AKT-mTOR pathway is involved in regulation of numerous important cell processes including cell growth, differentiation, and metabolism. The PI3Kα isoform has received particular attention as a novel molecular target in gene therapy, since this isoform plays critical roles in tumor progression and tumor blood flow and angiogenesis. However, the role of PI3Kα and other class I isoforms, i.e. PI3Kβ, γ, δ, in the regulation of vascular tone and regional blood flow are largely unknown. We used novel isoform-specific PI3K inhibitors and mice deficient in both PI3Kγ and PI3Kδ (Pik3cg–/–/Pik3cd–/–) to define the putative contribution of PI3K isoform(s) to arterial vasoconstriction. Wire myography was used to measure isometric contractions of isolated murine mesenteric arterial rings. Phenylephrine-dependent contractions were inhibited by the pan PI3K inhibitors wortmannin (100 nM) and LY294002 (10 μM). These vasoconstrictions were also inhibited by the PI3Kα isoform inhibitors A66 (10 μM) and PI-103 (1 μM), but not by the PI3Kβ isoform inhibitor TGX 221 (100 nM). Pik3cg–/–/Pik3cd–/–-arteries showed normal vasoconstriction. We conclude that PI3Kα is an important downstream element in vasoconstrictor GPCR signaling, which contributes to arterial vasocontraction via α1-adrenergic receptors. Our results highlight a regulatory role of PI3Kα in the cardiovascular system, which widens the spectrum of gene therapy approaches targeting PI3Kα in cancer cells and tumor angiogenesis and regional blood flow.

About the authors

D. Tsvetkov

Experimental and Clinical Research Center, Section Nephrology/Intensive Care

Email: maik.gollasch@charite.de
Germany, Berlin, 13125

A. Shymanets

Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Pharmacology and Experimental Therapy

Email: maik.gollasch@charite.de
Germany, Tübingen, 72074

Yu Huang

School of Biomedical Sciences

Email: maik.gollasch@charite.de
China, 223A, Lo Kwee-Seong Integrated Biomedical Sciences Building, Area 39, Hong Kong

K. Bucher

Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Pharmacology and Experimental Therapy

Email: maik.gollasch@charite.de
Germany, Tübingen, 72074

R. Piekorz

Institute for Biochemistry and Molecular Biology II

Email: maik.gollasch@charite.de
Germany, Düsseldorf, 40225

E. Hirsch

Molecular Biotechnology Centre, Department of Molecular Biotechnology and Health Sciences

Email: maik.gollasch@charite.de
Italy, Turin, 10126

S. Beer-Hammer

Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Pharmacology and Experimental Therapy

Email: maik.gollasch@charite.de
Germany, Tübingen, 72074

C. Harteneck

Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Pharmacology and Experimental Therapy

Email: maik.gollasch@charite.de
Germany, Tübingen, 72074

M. Gollasch

Experimental and Clinical Research Center, Section Nephrology/Intensive Care

Author for correspondence.
Email: maik.gollasch@charite.de
Germany, Berlin, 13125

B. Nürnberg

Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Pharmacology and Experimental Therapy

Email: maik.gollasch@charite.de
Germany, Tübingen, 72074


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