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Repurposing FDA-approved drugs as therapeutics to treat Rift Valley fever virus infection.

Benedict A, Bansal N, Senina S, Hooper I, Lundberg L, de la Fuente C, Narayanan A, Gutting B, Kehn-Hall K - Front Microbiol (2015)

Bottom Line: Several drugs from varying compound classes, including inhibitors of growth factor receptors, microtubule assembly/disassembly, and DNA synthesis, were found to reduce RVFV replication.The hepatocellular and renal cell carcinoma drug, sorafenib, was the most effective inhibitor, being non-toxic and demonstrating inhibition of RVFV in a cell-type and virus strain independent manner.Computational modeling studies also support this conclusion. siRNA knockdown of Raf proteins indicated that non-classical targets of sorafenib are likely important for the replication of RVFV.

View Article: PubMed Central - PubMed

Affiliation: National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University Manassas, VA, USA.

ABSTRACT
There are currently no FDA-approved therapeutics available to treat Rift Valley fever virus (RVFV) infection. In an effort to repurpose drugs for RVFV treatment, a library of FDA-approved drugs was screened to determine their ability to inhibit RVFV. Several drugs from varying compound classes, including inhibitors of growth factor receptors, microtubule assembly/disassembly, and DNA synthesis, were found to reduce RVFV replication. The hepatocellular and renal cell carcinoma drug, sorafenib, was the most effective inhibitor, being non-toxic and demonstrating inhibition of RVFV in a cell-type and virus strain independent manner. Mechanism of action studies indicated that sorafenib targets at least two stages in the virus infectious cycle, RNA synthesis and viral egress. Computational modeling studies also support this conclusion. siRNA knockdown of Raf proteins indicated that non-classical targets of sorafenib are likely important for the replication of RVFV.

No MeSH data available.


Related in: MedlinePlus

Sorafenib affects an early stage of infection. (A,B) HSAECs were pre-treated, infected and post-treated with either DMSO or sorafenib. Supernatants and lysates in RLT buffer were collected at the indicated times post-infection. RNA was extracted from all samples and a qRT-PCR was performed to determine viral genomic copies. The average and standard deviation of three biological replicates are plotted. (C) HSAECs were treated at various times relative to MP12 ΔNSs-Luc infection (1 h pre-treatment, at the end of 1 h infection, at 2, 4, 6 hpi, both pre-treated and post-treated). Lysates were collected at 24 hpi and analyzed for luciferase activity. Data is graphed in percentage RLU of the DMSO control. *p ≤ 0.01.
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Figure 4: Sorafenib affects an early stage of infection. (A,B) HSAECs were pre-treated, infected and post-treated with either DMSO or sorafenib. Supernatants and lysates in RLT buffer were collected at the indicated times post-infection. RNA was extracted from all samples and a qRT-PCR was performed to determine viral genomic copies. The average and standard deviation of three biological replicates are plotted. (C) HSAECs were treated at various times relative to MP12 ΔNSs-Luc infection (1 h pre-treatment, at the end of 1 h infection, at 2, 4, 6 hpi, both pre-treated and post-treated). Lysates were collected at 24 hpi and analyzed for luciferase activity. Data is graphed in percentage RLU of the DMSO control. *p ≤ 0.01.

Mentions: In order to gather more information about which stage of the virus life cycle sorafenib affects, a time course was performed using qRT-PCR to measure accumulation of viral RNA from cell lysates (intracellular RNA, Figure 4A) and supernatants (extracellular RNA, Figure 4B). No difference in viral RNA levels between DMSO and sorafenib treated samples was observed at 2 hpi, suggesting that sorafenib does not impair RVFV entry. A difference in viral RNA levels was detected as early as 4 hpi (Figure 4A). There continued to be only a small increase in intracellular viral RNA levels in sorafenib treated samples over time compared to the exponential increase in DMSO treated samples. This dramatic delay suggests that viral RNA production may be impaired by sorafenib. The extracellular genomic copies in sorafenib treated cells do not significantly change from 0 to 24 h (Figure 4B). The lack of extracellular viral RNA output may simply be a consequence of the decreased of intracellular viral RNA production. However, it is important to note that there was approximately 1.5 log increase in intracellular viral RNA from sorafenib-treated samples observed over time, without a corresponding increase in extracellular RNA levels. These data suggest that an additional virus life cycle step, possibly virus assembly or egress, may be impaired.


Repurposing FDA-approved drugs as therapeutics to treat Rift Valley fever virus infection.

Benedict A, Bansal N, Senina S, Hooper I, Lundberg L, de la Fuente C, Narayanan A, Gutting B, Kehn-Hall K - Front Microbiol (2015)

Sorafenib affects an early stage of infection. (A,B) HSAECs were pre-treated, infected and post-treated with either DMSO or sorafenib. Supernatants and lysates in RLT buffer were collected at the indicated times post-infection. RNA was extracted from all samples and a qRT-PCR was performed to determine viral genomic copies. The average and standard deviation of three biological replicates are plotted. (C) HSAECs were treated at various times relative to MP12 ΔNSs-Luc infection (1 h pre-treatment, at the end of 1 h infection, at 2, 4, 6 hpi, both pre-treated and post-treated). Lysates were collected at 24 hpi and analyzed for luciferase activity. Data is graphed in percentage RLU of the DMSO control. *p ≤ 0.01.
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Figure 4: Sorafenib affects an early stage of infection. (A,B) HSAECs were pre-treated, infected and post-treated with either DMSO or sorafenib. Supernatants and lysates in RLT buffer were collected at the indicated times post-infection. RNA was extracted from all samples and a qRT-PCR was performed to determine viral genomic copies. The average and standard deviation of three biological replicates are plotted. (C) HSAECs were treated at various times relative to MP12 ΔNSs-Luc infection (1 h pre-treatment, at the end of 1 h infection, at 2, 4, 6 hpi, both pre-treated and post-treated). Lysates were collected at 24 hpi and analyzed for luciferase activity. Data is graphed in percentage RLU of the DMSO control. *p ≤ 0.01.
Mentions: In order to gather more information about which stage of the virus life cycle sorafenib affects, a time course was performed using qRT-PCR to measure accumulation of viral RNA from cell lysates (intracellular RNA, Figure 4A) and supernatants (extracellular RNA, Figure 4B). No difference in viral RNA levels between DMSO and sorafenib treated samples was observed at 2 hpi, suggesting that sorafenib does not impair RVFV entry. A difference in viral RNA levels was detected as early as 4 hpi (Figure 4A). There continued to be only a small increase in intracellular viral RNA levels in sorafenib treated samples over time compared to the exponential increase in DMSO treated samples. This dramatic delay suggests that viral RNA production may be impaired by sorafenib. The extracellular genomic copies in sorafenib treated cells do not significantly change from 0 to 24 h (Figure 4B). The lack of extracellular viral RNA output may simply be a consequence of the decreased of intracellular viral RNA production. However, it is important to note that there was approximately 1.5 log increase in intracellular viral RNA from sorafenib-treated samples observed over time, without a corresponding increase in extracellular RNA levels. These data suggest that an additional virus life cycle step, possibly virus assembly or egress, may be impaired.

Bottom Line: Several drugs from varying compound classes, including inhibitors of growth factor receptors, microtubule assembly/disassembly, and DNA synthesis, were found to reduce RVFV replication.The hepatocellular and renal cell carcinoma drug, sorafenib, was the most effective inhibitor, being non-toxic and demonstrating inhibition of RVFV in a cell-type and virus strain independent manner.Computational modeling studies also support this conclusion. siRNA knockdown of Raf proteins indicated that non-classical targets of sorafenib are likely important for the replication of RVFV.

View Article: PubMed Central - PubMed

Affiliation: National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University Manassas, VA, USA.

ABSTRACT
There are currently no FDA-approved therapeutics available to treat Rift Valley fever virus (RVFV) infection. In an effort to repurpose drugs for RVFV treatment, a library of FDA-approved drugs was screened to determine their ability to inhibit RVFV. Several drugs from varying compound classes, including inhibitors of growth factor receptors, microtubule assembly/disassembly, and DNA synthesis, were found to reduce RVFV replication. The hepatocellular and renal cell carcinoma drug, sorafenib, was the most effective inhibitor, being non-toxic and demonstrating inhibition of RVFV in a cell-type and virus strain independent manner. Mechanism of action studies indicated that sorafenib targets at least two stages in the virus infectious cycle, RNA synthesis and viral egress. Computational modeling studies also support this conclusion. siRNA knockdown of Raf proteins indicated that non-classical targets of sorafenib are likely important for the replication of RVFV.

No MeSH data available.


Related in: MedlinePlus