Expression of HIV-1 Reverse Transcriptase in Murine Cancer Cells Increases Mitochondrial Respiration

— Changes in metabolic pathways are often associated with the development of a wide range of pathologies. Increased glycolysis under conditions of sufficient tissue oxygen supply and its dissociation from the Krebs cycle, known as aerobic glycolysis or the Warburg effect, is a hallmark of many malignant neoplasms. Identification of specific metabolic shifts can characterize the metabolic programming of individual types of tumor cells, the stage of their transformation, and predict their metastatic potential. Viral infection can also alter the metabolism of cells to support the process of viral replication. Infection with human immunodeficiency virus type 1 (HIV-1) is associated with an increased incidence of various cancers, and for some viral proteins a direct oncogenic effect was demonstrated. In particular, we showed that the expression of HIV-1 reverse transcriptase (RT) in 4T1 breast adenocarcinoma cells increases the tumorigenic and metastatic potential of cells in vitro and in vivo by a mechanism associated with the ability of RT to induce reactive oxygen species in cells (ROS). The aim of this work was to study the molecular mechanism of this process, namely the effect of HIV-1 RT on the key metabolic pathways associated with tumor progression: glycolysis and mitochondrial respiration. Expression of HIV-1 RT had no effect on the glycolysis process. At the same time, it led to an increase in mitochondrial respiration and the level of ATP synthesis in the cell, while not affecting the availability of the substrates, carbon donors for the Krebs cycle, which excludes the effect of RT on the metabolic enzymes of cells. Increased mitochondrial respiration was associated with restoration of the mitochondrial network despite the RT-induced reduction in mitochondrial mass. Increased mitochondrial respiration may increase cell motility, which explains their increased tumorigenicity and metastatic potential. These data are important for understanding the pathogenesis of HIV-1 infection, including the stimulation of the formation and spread of HIV-1 associated malignancies.