Analysis of the thymidine kinase of a herpes simplex virus type 1 isolate that exhibits resistance to (E)-5-(2-bromovinyl)-2'-deoxyuridine.
Acyclovir/pharmacology; Amino Acid Sequence; Antiviral Agents/metabolism/*pharmacology; Base Sequence; Binding Sites; Bromodeoxyuridine/*analogs & derivatives/metabolism/pharmacology; Deoxyuridine/analogs & derivatives/pharmacology; DNA; Drug Resistance; Herpesvirus 1; Human/drug effects/*enzymology/genetics; Humans; Kinetics; Microbial; Molecular Sequence Data; Phosphonoacetic Acid/pharmacology; Phosphorylation; Point Mutation/genetics; Sequence Analysis; Thymidine Kinase/genetics/metabolism; Thymidine/metabolism; Vidarabine/pharmacology
The mechanism responsible for the decreased sensitivity of a clinical herpes simplex virus type 1 (HSV-1) isolate, HSV-145, to (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) was examined. Measurements of 50% inhibitory doses of several drugs demonstrated that although HSV-145 was sensitive to phosphonoacetic acid, adenine arabinoside and acyclovir, its sensitivity to BVDU and 5-(2-chloroethyl)-2'-deoxyuridine was significantly less than that normally observed for HSV-1. Analysis of the thymidylate kinase (TMP-K) activity of HSV-145 thymidine kinase (TK) demonstrated a decreased level of TMP-K activity when compared to HSV-1 TK. The TMP-K activity of HSV-145 resembled that observed for HSV-2 and the TK-deficient strain HSV-1 TK-7. When the nucleotide sequence of the HSV-145 TK gene was compared to that of the HSV-1 strains C1(101) and SC16 a single nucleotide substitution (G changed to A at base position 502) was detected which would result in the substitution of threonine at amino acid position 168 for alanine. The substitution is the same as that for the laboratory-derived BVDU-resistant virus HSV-1 SC16B3. Collectively, these studies highlight the importance of amino acid conservation at position 168 of the HSV-1 TK in conferring efficient TMP-K activity and BVDU sensitivity.
Wilber B A; Docherty J J
The Journal of general virology
1994
1994-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1099/0022-1317-75-7-1743" target="_blank" rel="noreferrer noopener">10.1099/0022-1317-75-7-1743</a>
Flow cytometric and ultrastructural aspects of the synergistic antitumor activity of vitamin C-vitamin K3 combinations against human prostatic carcinoma cells.
*Prostatic Neoplasms; Antineoplastic Combined Chemotherapy Protocols/*pharmacology; Ascorbic Acid/administration & dosage; Cultured/drug effects/metabolism/ultrastructure; DNA/biosynthesis; Drug Synergism; Electron; Flow Cytometry; Hemostatics/administration & dosage; Humans; Male; Microscopy; Scanning; Thymidine/metabolism; Tritium; Tumor Cells; Vitamin K/administration & dosage
Transmission and scanning electron microscopy and flow cytometry were employed to characterize the cytotoxic effects of vitamin C (VC), vitamin K3 (VK3), or VC-VK3 combinations on a human prostate carcinoma cell line (DU145) following a 1-h vitamin treatment and a 24-h incubation in culture medium. Cells exposed to VC exhibited membranous blebs, aberrant microvillar morphology, mitochondria with swollen cristae and intramitochondrial deposits, as well as nucleoli with segregated components. VK3-treated cells displayed a damaged cytoskeleton and membranes, a cytoplasm which contained large lumen, condensed polysomes, and severely damaged mitochondria with residual bodies, and nuclei which exhibited chromatic condensation, pyknosis, and karyolysis. VC-VK3-treated cells exhibited characteristics consistent with necrosis, i.e. swollen mitochondria and swollen, achromatic nuclei with marginated chromatin and intact envelopes, while other cells displayed characteristics consistent with apoptosis, i.e. expulsion of organelle-containing blebs, margination of nuclear chromatin, and segregation of nucleolar components. Vitamin treatment also decreased DNA synthesis, induced a S/G2 block in the cell cycle, and resulted in the accumulation of fragmented DNA. These results suggested that increased oxidative stress, subsequent membrane damage, and DNA fragmentation were responsible for enhanced cytotoxicity of the vitamin combination.
Jamison J M; Gilloteaux J; Venugopal M; Koch J A; Sowick C; Shah R; Summers J L
Tissue & cell
1996
1996-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/s0040-8166(96)80072-3" target="_blank" rel="noreferrer noopener">10.1016/s0040-8166(96)80072-3</a>