Title

Identification of novel PTPN1/PTPN2 inhibitors to target latent HIV reservoirs

Presenter

Alberto Bosque

Authors

C. Levinger¹, J.N. Howard¹, C. Holmberg¹, D. Copertino², E. McMahon¹, R.B. Jones², A. Bosque¹

Institutions

¹The George Washington University, Microbiology, Immunology and Tropical Medicine, Washington DC, United States, ²Weill Cornell Medicine, Department of Infectious Diseases Division of Medicine, New York, United States

BACKGROUND: 3-Hydroxy-1,2,3-Benzotriazin-4(3H)-one (HODHBt) is a latency reversal agent (LRA) that enhanced ?c-cytokine signaling by increasing phosphorylation and transcriptional activity of STAT5. We have shown that HODHBt increases IL-2 and IL-15 activation of STAT5, promoting reactivation from latency in a primary cell model and cells isolated from people living with HIV. Furthermore, we have shown that HODHBt enhances IL-15 mediated NK and CD8T cell effector function. Recently, we used cellular-thermal shift assay followed with mass-spectrometry (CETSA-MS) to uncover the HODHBt target. We have found that HODHBt binds and inhibits the catalytic domain of the phosphatases PTPN1 and PTPN2. In spite of the positive properties of this class of compounds towards developing HIV cure approaches, their activity in the high micromolar range hinders further pharmacological development. In here, we aimed to identify novel inhibitors and/or novel scaffold molecules targeting PTPN1/PTPN2 that could be further developed towards HIV cure strategies
METHODS: We used an in vitro fluorogenic enzymatic assay to screen for compounds that inhibit PTPN1 and PTPN2. We tested 52 HODHBt derivatives and 94 known phosphatase inhibitors. Those with higher activity than HODHBt were then tested for their ability to enhance IL-2 mediated STAT5 transcriptional activation in the HEK-Blue IL-2 cell line.
RESULTS: From the 146 tested compounds, we have identified one HODHBt derivative and two phosphatase inhibitors with enhanced activity relative to our lead compound HODHBt. These compounds inhibit both PTPN1 and PTPN2 in vitro and have increased activity to enhance STAT5 transcriptional activity compared to HODHBt in the low micromolar range.

Identification of novel phosphatase inhibitors to target PTPN1 and PTPN2.
CONCLUSIONS: In conclusion, we have identified novel PTPN1/PTPN2 inhibitors with improved pharmacological capabilities that our lead compound HODHBt. Further medicinal chemistry and validation in ex vivo and in vivo models of HIV latency is currently underway.

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