Inhibition of HIV-1 infection in humanized mice and metabolic stability of protein phosphatase-1-targeting small molecule 1E7-03.

// Xionghao Lin 1 , Namita Kumari 1 , Catherine DeMarino 6 , Yasemin Saygideger Kont 5 , Tatiana Ammosova 1, 2, 8 , Amol Kulkarni 4 , Marina Jerebtsova 3 , Guelaguetza Vazquez-Meves 1 , Andrey Ivanov 1 , Dmytro Kovalskyy 7 , Aykut Uren 5 , Fatah Kashanchi 6 and Sergei Nekhai 1, 2, 3 1 Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC, USA 2 Department of Medicine, College of Medicine, Howard University, Washington, DC, USA 3 Department of Microbiology, College of Medicine, Howard University, Washington, DC, USA 4 Department of Pharmaceutical Sciences, College of Pharmacy, Howard University, Washington, DC, USA 5 Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA 6 Laboratory of Molecular Virology, George Mason University, Manassas, VA, USA 7 Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, USA 8 Yakut Science Center for Complex Medical Problems, Yakutsk, Russia Correspondence to: Sergei Nekhai, email: snekhai@howard.edu Keywords: HIV-1, protein phosphatase-1, small molecule HIV-1 inhibitor, HIV-1 infected humanized mice, metabolic stability Received: March 22, 2017      Accepted: July 14, 2017      Published: August 07, 2017 ABSTRACT We recently identified the protein phosphatase-1 - targeting compound, 1E7-03 which inhibited HIV-1 in vitro . Here, we investigated the effect of 1E7-03 on HIV-1 infection in vivo by analyzing its metabolic stability and antiviral activity of 1E7-03 and its metabolites in HIV-1 infected NSG-humanized mice. 1E7-03 was degraded in serum and formed two major degradation products, DP1 and DP3, which bound protein phosphatase-1 in vitro . However, their anti-viral activities were significantly reduced due to inefficient cell permeability. In cultured cells, 1E7-03 reduced expression of several protein phosphatase-1 regulatory subunits including Sds22 as determined by a label free quantitative proteomics analysis. In HIV-1-infected humanized mice, 1E7-03 significantly reduced plasma HIV-1 RNA levels, similar to the previously described HIV-1 transcription inhibitor F07#13. We synthesized a DP1 analog, DP1-07 with a truncated side chain, which showed improved cell permeability and longer pharmacokinetic retention in mice. But DP1-07 was less efficient than 1E7-03 as a HIV-1 inhibitor both in vitro and in vivo , indicating that the full side chain of 1E7-03 was essential for its anti-HIV activity. Analysis of 1E7-03 stability in plasma and liver microsomes showed that the compound was stable in human, primate and ferret plasma but not in rodent plasma. However, 1E7-03 was not stable in human liver microsomes. Our findings suggest that 1E7-03 is a good candidate for future development of HIV-1 transcription inhibitors. Further structural modification and advanced formulations are needed to improve its metabolic stability and enhance its antiviral activity in non-human primate animals and humans.