Discipline: Biological Sciences
Room: Exhibit Hall A
Dana Cadet - Bowie State University
Co-Author(s): Xionghao Lin, Howard University, Washington DC; Sajith Meleveetil, Howard University, Washington DC; Songping Wang, Howard University, Washington DC; Andrey I. Ivanov, Howard University, Washington DC; Amol A. Kulkarni, Howard University, Washington DC; Sergei Nekhai, Howard University, Washington DC
Human immunodeficiency virus-1 (HIV-1) remains a severe burden worldwide. While HIV/AIDS can be managed with current antiretroviral drugs, these agents are incapable of clearing the virus, do not target HIV transcription that is reactivated if the treatment is interrupted, and require life-long administration to prevent relapse. Long-term use of antiretroviral drugs contributes to clinical metabolic disturbances, organ damage and drives drug resistance. Therefore, targeting HIV-1 transcription with a new class of anti-HIV drugs may help in preventing HIV-1 reactivation and reach a functional cure. Previously we have identified protein phosphatase-1 (PP1) as an important regulator of HIV-1 Tat dependent transcription. A small molecule 1E7-03 was identified as the optimum PP1-targeting compound, which showed HIV-1 inhibition with IC50 about 5 ?M in cell culture and reduced HIV-1 replication by 40-fold in HIV infected humanized mice. However, metabolic study showed that 1E7-03 was not stable in mouse plasma both in vitro and in vivo. It was degraded into a major product DP1 in 30 mins. DP1 was about 10-fold less efficient than 1E7-03 duo to its poor cell permeability. This is very likely to impair the in vivo antiviral efficacy of 1E7-03. In this study, to obtain new PP1-targeting small molecules with good HIV-1 inhibition and metabolic stability, we carried out structural optimization of 1E7-03 based on its identified labile sites. We synthesized 52 analogs of 1E7-03 by replacing the labile linker with more stable substructures such as urea, piperazine etc. Their HIV-1 inhibitory activity was evaluated using one round HIV-1 infection with VSV-G pseudotyped HIV-1-Luc virus. Three analogs SAM-75, SAM-81 and SAM-82 with an urea substructure showed slightly better or comparable IC50s at 3.68 uM, 4.53 uM and 4.45 uM comparing to 1E7-03 (IC50=4.78 uM). Importantly, compound SAM-75 showed lower toxicity (CC50>100 uM, cell viability is about 80% at 100 uM) than 1E7-03 (CC50 =100 uM). To test the metabolic stability of new analogs, 10 mM of compound stock solution in DMSO was mixed with mouse serum to a final concentration of 10 ?M and incubated at 37?C. Aliquots were collected at different time points for up to 24 hrs and processed for liquid chromatography-Fourier transform mass spectrometry (LC/FT-MS) analysis. The result showed that SAM-75 was 100% stable after 24 hrs of incubation in mouse serum, while 1E7-03 showed 80% degradation in 30 mins and 98% degradation after 24 hrs of incubation. Taken together, we have optimized PP1-targeting HIV-1 transcription inhibitor 1E7-03 to new analogs. Analog SAM-75 showed better HIV-1 inhibition, less toxicity and improved metabolic stability. In future, we are planning to test HIV-1 inhibition of new 1E7-03 analogs in HIV-1 humanized mice and further explore the antiviral mechanism of PP1-targeting small molecules.
Funder Acknowledgement(s): This project was supported by the Research Grants: Howard University Summer Research Experience Program in Oral Health Disparity for Underrepresented Racial and Ethnic Students (5R25DE025778) from NIDCR (PI: XG); Pilot Award from the District of Columbia Center for AIDS Research, a NIH funded Program (AI117970) (PI: XL); Core C: Basic Sciences Core (5P30AI117970) from NIAID (PI: SN); Center for Hemoglobin Research in Minorities (CHaRM) (1P50HL118006) from NHLBI (PI: SN); Inhibition of HIV-1 in Sickle Cell Disease (1R01HL125005) from NHLBI (PI: SN).
Faculty Advisor: Dr. Xionghao Lin, firstname.lastname@example.org
Role: I have measured the HIV-1 inhibitory activity, cytotoxicity and metabolic stability of compounds SAM-75, SAM-81 and SAM-82. I assisted the data analysis and graph plotting. In addition, I wrote the abstract draft.