Effect of furoxans on smooth muscle cell proliferation by SILAC experiments

Physiologically, smooth muscle cells (SMCs) and nitric oxide (NO) produced by endothelial cells strictly cooperate to maintain vascular homeostasis. In atherosclerosis, this equilibrium is altered, therefore molecules, able to provide exogenous NO and inhibit SMC proliferation, may represent valuable anti-atherosclerotic agents. Searching for dual anti-proliferative and NO-donor molecules, we found that furoxans significantly decreased SMC proliferation in vitro, albeit with different potencies. We therefore assessed whether this property is dependent on their thiol-induced ring opening. Indeed, while furazans (analogues unable to release NO) are not effective, furoxans’ inhibitory potency parallels with the electron-attractor capacity of the group in 3 of the ring, making this effect tunable. To demonstrate whether their specific block on G1-S phase could be NO-dependent, we supplemented SMCs with furoxans and inhibitors of GMP- and/or of the polyamines pathway, which regulate NO-induced SMC proliferation, but they failed in preventing the anti-proliferative effect. To find the real mechanism of this property, we performed a proteomics study, using a SILAC approach, revealing eleven cellular proteins (with SUMO1 being central) statistically deregulated by furoxans and involved in cell homeostasis/proliferation. Altogether, thanks to their dual effect and pharmacological flexibility, furoxans may be evaluated in future as anti-atherosclerotic molecules.