Escape Mutations in NS4B Render Dengue Virus Insensitive to the Antiviral Activity of the Paracetamol Metabolite AM404.
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ABSTRACT:
SUBMITTER: van Cleef KW
PROVIDER: S-EPMC4808173 | biostudies-literature | 2016 Apr
REPOSITORIES: biostudies-literature
Publications
Escape Mutations in NS4B Render Dengue Virus Insensitive to the Antiviral Activity of the Paracetamol Metabolite AM404.
van Cleef Koen W R KW Overheul Gijs J GJ Thomassen Michael C MC Marjakangas Jenni M JM van Rij Ronald P RP
Antimicrobial agents and chemotherapy 20160325 4
Despite the enormous disease burden associated with dengue virus infections, a licensed antiviral drug is lacking. Here, we show that the paracetamol (acetaminophen) metabolite AM404 inhibits dengue virus replication. Moreover, we find that mutations in NS4B that were previously found to confer resistance to the antiviral compounds NITD-618 and SDM25N also render dengue virus insensitive to AM404. Our work provides further support for NS4B as a direct or indirect target for antiviral drug develo ...[more]
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Project description:The DNA repair protein, O(6)-alkylguanine-DNA alkyltransferase (AGT), is inactivated by reaction with the pseudosubstrate, O(6)-benzylguanine (BG). This inactivation sensitizes tumour cells to chemotherapeutic alkylating agents, and BG is aimed at enhancing cancer treatment in clinical trials. Point mutations in a 24 amino acid sequence likely to form the BG-binding pocket were identified using a screening method designed to identify BG-resistant mutants. It was found that alterations in 21 of these residues were able to render AGT resistant to BG. These included mutations at the highly conserved residues Lys(165), Leu(168) and Leu(169). The two positions at which changes led to the largest increase in resistance to BG were Gly(156) and Lys(165). Eleven mutants at Gly(156) were identified, with increases in resistance ranging from 190-fold (G156V) to 4400-fold (G156P). Two mutants at Lys(165) found in the screen (K165S and K165A) showed 620-fold and 100-fold increases in resistance to BG. Two mutants at the Ser(159) position (S159I and S159V) were >80-fold more resistant than wild-type AGT. Eleven active mutants at Leu(169) were also resistant to BG, but with lower increases (5-86-fold). Fourteen BG-resistant mutants were found for position Cys(150), with 3-26-fold increases in the amount of inhibitor needed to produce a 50% loss of activity in a 30 min incubation. Six BG-resistant mutants at Asn(157) were found with increases of 4-13-fold. These results show that many changes can render human AGT resistant to BG without preventing the ability to protect tumour cells from therapeutic alkylating agents.
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