Development and evaluation of a simple and effective RT-qPCR inhibitory assay for detection of the efficacy of compounds towards HIV reverse transcriptase

Assessing the actual efficacy of compounds to directly inhibit HIV reverse transcriptase (RT) activity is a main goal in preclinical antiretroviral studies. Our previous studies demonstrated that the effects of inhibitor compounds towards HIV-RT could be efficiently assessed through a simple cell-free assay based on conventional reverse transcription PCR. In the present study, we describe a modified variant of our assay, termed RT real-time quantitative PCR inhibitory assay (RTqPCR-IA), in which the ability of compounds to restrict the complementary DNA (cDNA) generation by HIV-RT using a specific RNA template is performed by the real-time technique, in order to improve both accuracy and sensitivity of the method. As specific RNA template, RNA extracted from stable transfectants ectopically expressing the herpes simplex virus 1 glycoprotein D gene was utilized. HIV-RT, of both commercial or house-made viral lysate origin, was employed for the assay. To assess the reliability of RT-qPCR-IA, we performed a comparative, quantitative analysis of the dose-dependent effect exerted by known nucleotide and non-nucleotide reverse-transcriptase inhibitors, using the SYBR Green dye chemistry as detection system. The results obtained with RT-qPCR-IA were compared to that obtained using a one-step PicoGreen technology-based commercial kit. The outcome of our study indicates that the development of the novel RT-qPCR-IA will provide rapid and accurate evaluation of the inhibitory efficacy of compounds towards HIV-RT activity. This evaluation could be very useful for large-scale screening of potential new anti-HIV drugs.