Thalidomide attenuates nitric oxide-driven angiogenesis by interacting with soluble guanylyl cyclase.
OBJECTIVE
Nitric oxide (NO) promotes angiogenesis by activating endothelial cells. Thalidomide arrests angiogenesis by interacting with the NO pathway, but its putative targets are not known. Here, we have attempted to identify these targets.


METHODS
Cell-based angiogenesis assays (wound healing of monolayers and tube formation in ECV304, EAhy926 and bovine arterial endothelial cells), along with ex vivo and in vivo angiogenesis assays, were used to explore interactions between thalidomide and NO. We also carried out in silico homology modelling and docking studies to elucidate possible molecular interactions of thalidomide and soluble guanylyl cyclase (sGC).


RESULTS
Thalidomide inhibited pro-angiogenic functions in endothelial cell cultures, whereas 8-bromo-cGMP, sildenafil (a phosphodiesterase inhibitor) or a NO donor [sodium nitroprusside (SNP)] increased these functions. The inhibitory effects of thalidomide were reversed by adding 8-bromo-cGMP or sildenafil, but not by SNP. Immunoassays showed a concentration-dependent decrease of cGMP in endothelial cells with thalidomide, without affecting the expression level of sGC protein. These results suggested that thalidomide inhibited the activity of sGC. Molecular modelling and docking experiments revealed that thalidomide could interact with the catalytic domain of sGC, which would explain the inhibitory effects of thalidomide on NO-dependent angiogenesis.


CONCLUSIONS
Our results showed that thalidomide interacted with sGC, suppressing cGMP levels in endothelial cells, thus exerting its anti-angiogenic effects. These results could lead to the formulation of thalidomide-based drugs to curb angiogenesis by targeting sGC.
Majumder
Syamantak
S
Vascular Biology Lab, AU-KBC Research Centre, Anna University, Chennai, TN, India.
Rajaram
Megha
M
Muley
Ajit
A
Reddy
Himabindu S
HS
Tamilarasan
K P
KP
Kolluru
Gopi Krishna
GK
Sinha
Swaraj
S
Siamwala
Jamila H
JH
Gupta
Ravi
R
Ilavarasan
R
R
Venkataraman
S
S
Sivakumar
K C
KC
Anishetty
Sharmila
S
Kumar
Pradeep G
PG
Chatterjee
Suvro
S
D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D020134:Catalytic Domain / Q000187:drug effects; D002417:Cattle; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D006162:Guanylate Cyclase / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D008297:Male; D008958:Models, Molecular; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D009569:Nitric Oxide / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects* / Q000378:metabolism; D000071756:Soluble Guanylyl Cyclase; D013792:Thalidomide / Q000008:administration & dosage / Q000494:pharmacology*; D014471:Umbilical Veins; D014945:Wound Healing / Q000187:drug effects
D020533:Angiogenesis Inhibitors; D018160:Receptors, Cytoplasmic and Nuclear; D009569:Nitric Oxide; D013792:Thalidomide; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP