title: Double-stranded RNA-dependent protein kinase-dependent apoptosis induction by a novel small compound.
abstract: The interferon-induced, double-stranded RNA-dependent protein kinase (PKR) can play critical roles in inhibiting virus replication and inducing apoptosis. To develop new agents that may inhibit viral replication or induce apoptosis in cancer cells via the PKR signaling pathway, we screened a chemical library for compounds that have differential cytotoxic effects on wild-type [mouse embryonic fibroblast (MEF)/PKR(+/+)] and PKR-knockout [MEF/PKR(-/-)] mouse embryonic fibroblast cells. We identified a synthetic compound, BEPP [1H-benzimidazole1-ethanol,2,3-dihydro-2-imino-a-(phenoxymethyl)-3-(phenylmethyl)-,monohydrochloride], that induces a cytotoxic effect more effectively in MEF/PKR(+/+) cells than in MEF/PKR(-/-) cells. BEPP also relatively effectively inhibited the growth of a human lung cancer cell line overexpressing PKR, compared with other cancer cell lines. In sensitive cells, BEPP induced apoptosis with activation of caspase-3. Treatment with BEPP led to increased phosphorylation of PKR and eIF2alpha, increased expression of BAX, and decreased expression of Bcl-2. BEPP-induced apoptosis was PKR dependent and was blocked by the adenovector expressing the dominant-negative PKR. Furthermore, pretreatment of HeLa cells at a noncytotoxic dose of BEPP effectively inhibited Vaccinia virus replication. Together, our results suggest that BEPP and its analogs may induce PKR-dependent apoptosis and inhibition of viral replication and that they can be a potential anticancer or anti-virus agent.
authors.affiliation: Department of Colorectal Surgery, Sir Run Run Shaw Hospital, Zhejiang University, Zhejiang, China.
authors.forename: Wenxian
authors.initials: W
authors.lastname: Hu
authors.forename: Wayne
authors.initials: W
authors.lastname: Hofstetter
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wei
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Zhou
authors.forename: Abujiang
authors.initials: A
authors.lastname: Pataer
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Bingliang
authors.initials: B
authors.lastname: Fang
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Swisher
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001562:Benzimidazoles / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D008175:Lung Neoplasms; D051379:Mice; D018345:Mice, Knockout; D012330:RNA, Double-Stranded / Q000235:genetics; D014616:Vaccinia virus / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects; D019892:eIF-2 Kinase / Q000172:deficiency* / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001562:Benzimidazoles; D012330:RNA, Double-Stranded; D019892:eIF-2 Kinase