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Abstract
The objective of this study was to compare the limit of agreement of creatinine clearance (CrCl) estimated by different equations with the CrCl measured by 24-hour urine collection in Hong Kong Chinese patients with systemic lupus erythematosus (SLE). Forty-three SLE patients with mild to moderate renal impairment (serum creatinine concentration 80 mol/L to 300 mol/L for females; and 106 mol/L to 300 mol/L for males) and not requiring renal replacement therapy were assessed. The estimated clearances were calculated by the Cockcroft-Gault (CG) equation, the Modification of Diet in Renal Disease (MDRD) study equation and the abbreviated MDRD (aMDRD) study equation. The estimated clearances were compared against the measured CrCl by 24- hour urine collection for their limit of agreement. Forty-three patients with mean (SD) age of 41.6 (8.4) years were assessed. As compared to the measured CrCl in patients with SLE, the clearances by CG equation, MDRD and aMDRD equations predicted a mean difference of 0.8% (95% confidence interval, 43.9-42.3%); 8.6% (95% CI, 24.3-7.2%) and 4.7% (95% CI, 21.4-12%), respectively. There is a tendency for the MDRD and aMDRD study equations to underestimate CrCl. The MDRD and aMDRD study equations have better predictive value than the CG equation.
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Affiliation(s)
- Y Y Leung
- Department of Medicine and Geriatrics, Tai Po Hospital, 9 Chuen On Road, Taipo, NT, Hong Kong SAR.
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2
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Ehsan MA, Peiris TAN, Wijayantha KGU, Olmstead MM, Arifin Z, Mazhar M, Lo KM, McKee V. Development of molecular precursors for deposition of indium sulphide thin film electrodes for photoelectrochemical applications. Dalton Trans 2013; 42:10919-28. [DOI: 10.1039/c3dt50781e] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3
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Lo KM, Seng RWC, Ngan NK. Synthesis and structures of binuclear dioxomolybdenum Schiff base complexes. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311092117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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4
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Lo KM, Jones SS, Hackett NR, Khorana HG. Specific amino acid substitutions in bacterioopsin: Replacement of a restriction fragment in the structural gene by synthetic DNA fragments containing altered codons. Proc Natl Acad Sci U S A 2010; 81:2285-9. [PMID: 16593452 PMCID: PMC345043 DOI: 10.1073/pnas.81.8.2285] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To study the mechanism of light-dependent proton translocation by bacteriorhodopsin, we have introduced single-codon changes in the gene so as to produce the following specific amino acid substitutions in the protein: Tyr-185 to Phe, Pro-186 to Leu, Trp-189 to Phe, Ser-193 to Ala, and Glu-194 to Gln. The strategy involved replacement of a 62-base-pair restriction fragment by synthetic DNA duplexes containing the modified nucleotide sequences. This required a unique restriction site (Xho I) at Ile-203 which was created by oligonucleotide-directed point mutagenesis. The six DNA duplexes corresponding to the modified native and mutant restriction fragments were all prepared by DNA ligase-catalyzed joining of chemically synthesized deoxyribooligonucleotides. The bacterioopsin expression plasmids reconstructed by using the synthetic DNA fragments were characterized by restriction analysis and DNA sequence determination. An extremely rapid, efficient, and general method for purification of the synthetic oligonucleotides and of DNA fragments was developed.
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Affiliation(s)
- K M Lo
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
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Wong CL, Lee KH, Lo KM, Chan OC, Goggins W, O WS, Chow PH. Ablation of paternal accessory sex glands imparts physical and behavioural abnormalities to the progeny: an in vivo study in the golden hamster. Theriogenology 2007; 68:654-62. [PMID: 17597198 DOI: 10.1016/j.theriogenology.2007.04.062] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Accepted: 04/19/2007] [Indexed: 11/21/2022]
Abstract
The functional significance of male accessory sex glands (ASG) remains unclear. This study explored their importance in reproduction. In previous investigations, embryos sired by males with ASG either totally or partially removed had a shift in the cell cycle and delayed cleavage during preimplantation development, higher incidence of apoptosis, early oviductal-uterine transit, higher proportion of embryo degeneration, lower implantation rate, and ultimately reduced fertility and fecundity. Some pups were born alive; but would they be normal? We hypothesized that the first generation offspring (F1) could also bear undesirable traits. To test our hypothesis, we raised and studied these F1 pups from birth to 8 weeks. We monitored physical growth and assessed behaviour such as nest patch odor preference, acoustic startle response (ASR) and exploratory activity. We detected deviations from the norm in physical growth, a premature cessation of nest patch odor preferences, accelerated acoustic startle habituation and more frequent rearing when exposed to a novel environment. In terms of structure, we found one incidence of diphallus with duplicated urethra. We concluded that sperm lacking contact with ASG secretions gave rise to progeny with abnormal traits.
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Affiliation(s)
- C L Wong
- Department of Anatomy, the Chinese University of Hong Kong, Hong Kong
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6
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Abstract
BACKGROUND AND PURPOSE Stroke patients may have an increased risk of fractures because of weak bones or an increased risk of falling. Our goal was to estimate the frequency of fracture after stroke and to identify those at greatest risk. METHODS This study incorporated 2 complementary strategies: a prospective, single-center, cohort study and an analysis of Scottish routine hospital discharge data. RESULTS Eighty-eight fractures (30% hip) occurred in 2696 hospital-referred stroke patients. The proportions sustaining any fracture or hip fracture within 2 years were 4% and 1.1%, respectively, 1.4 (95% CI, 0.92 to 2.07) times the rate of hip fracture in the general population (ie, observed number divided by expected number or standardized morbidity ratio). Female sex, older age, low abbreviated mental test score, and prestroke dependence were associated with an increased hip fracture rate. Routine data identified 129 935 acute stroke patients admitted to Scottish hospitals. During 363 447 patient-years, 4528 patients had hip fractures, 2.0% had fractures by 1 year, and 10.6% had fractures by 10 years. This is 1.7 times the rate of hip fracture in the general population and 2.3 times that in patients with myocardial infarction. Older patients predictably had the highest rate of poststroke hip fractures but a lower standardized morbidity ratio than younger patients. CONCLUSIONS Fractures after stroke are probably frequent and serious enough to justify the development of preventive strategies, but the modest event rate would mean that randomized, controlled trials to test these strategies specifically in stroke patients would need to enroll thousands of patients.
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Affiliation(s)
- M S Dennis
- Department of Clinical Neurosciences, University of Edinburgh, Edinburgh, UK.
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Sasaki H, Lo KM, Chen LB, Auclair D, Nakashima Y, Moriyama S, Fukai I, Tam C, Loda M, Fujii Y. Expression of Periostin, homologous with an insect cell adhesion molecule, as a prognostic marker in non-small cell lung cancers. Jpn J Cancer Res 2001; 92:869-73. [PMID: 11509119 PMCID: PMC5926835 DOI: 10.1111/j.1349-7006.2001.tb01174.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We used our palindromic polymerase chain reaction (PCR)-driven cDNA differential display technique to identify and isolate a gene, designated periostin, from cancer tissues and found it to be overexpressed in several human tumors. We attempted to determine the influence of periostin expression on clinical outcome in patients with non-small cell lung cancer (NSCLC) by reverse transcriptase (RT)-PCR analysis. Periostin gene was highly expressed at the tumor periphery of lung cancer tissue but not within the tumor by in situ RNA hybridization, suggesting that expression of periostin may be involved in the process of tumor invasion. Periostin transcripts were detected in 50 (49.0%) of the tumor samples, although some paired normal lung samples showed weak expression. There was no relationship between periostin gene expression and gender, N- or T-status. The NSCLC patients with periostin expression had significantly poorer survival than the patients without periostin expression (P = 0.0338).
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Affiliation(s)
- H Sasaki
- Department of Surgery II, Nagoya City University Medical School, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
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Jacobson JS, Troxel AB, Evans J, Klaus L, Vahdat L, Kinne D, Lo KM, Moore A, Rosenman PJ, Kaufman EL, Neugut AI, Grann VR. Randomized Trial of Black Cohosh for the Treatment of Hot Flashes Among Women With a History of Breast Cancer. J Clin Oncol 2001; 19:2739-45. [PMID: 11352967 DOI: 10.1200/jco.2001.19.10.2739] [Citation(s) in RCA: 223] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE: Most breast cancer survivors experience hot flashes; many use complementary or alternative remedies for these symptoms. We undertook a randomized clinical trial of black cohosh, a widely used herbal remedy for menopausal symptoms, among breast cancer patients. PATIENTS AND METHODS: Patients diagnosed with breast cancer who had completed their primary treatment were randomly assigned to black cohosh or placebo, stratified on tamoxifen use. At enrollment, patients completed a questionnaire about demographic factors and menopausal symptoms. Before starting to take the pills and at 30 and 60 days, they completed a 4-day hot flash diary. At the final visit, they completed another menopausal symptom questionnaire. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were measured in a subset of patients at the first and final visits. RESULTS: Of 85 patients (59 on tamoxifen, 26 not on tamoxifen) enrolled in the study, 42 were assigned to treatment and 43 were assigned to placebo; 69 completed all three hot flash diaries. Both treatment and placebo groups reported declines in number and intensity of hot flashes; the differences between the groups were not statistically significant. Both groups also reported improvements in menopausal symptoms that were, for the most part, not significantly different. Changes in blood levels of FSH and LH also did not differ in the two groups. CONCLUSION: Black cohosh was not significantly more efficacious than placebo against most menopausal symptoms, including number and intensity of hot flashes. Our study illustrates the feasibility and value of standard clinical trial methodology in assessing the efficacy and safety of herbal agents.
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Affiliation(s)
- J S Jacobson
- Herbert Irving Comprehensive Cancer Center and Joseph L. Mailman School of Public Health, Columbia University, and Weill-Cornell Medical College, New York, NY 10032, USA
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9
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Kuo CJ, LaMontagne KR, Garcia-Cardeña G, Ackley BD, Kalman D, Park S, Christofferson R, Kamihara J, Ding YH, Lo KM, Gillies S, Folkman J, Mulligan RC, Javaherian K. Oligomerization-dependent regulation of motility and morphogenesis by the collagen XVIII NC1/endostatin domain. J Cell Biol 2001; 152:1233-46. [PMID: 11257123 PMCID: PMC2199214 DOI: 10.1083/jcb.152.6.1233] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Collagen XVIII (c18) is a triple helical endothelial/epithelial basement membrane protein whose noncollagenous (NC)1 region trimerizes a COOH-terminal endostatin (ES) domain conserved in vertebrates, Caenorhabditis elegans and Drosophila. Here, the c18 NC1 domain functioned as a motility-inducing factor regulating the extracellular matrix (ECM)-dependent morphogenesis of endothelial and other cell types. This motogenic activity required ES domain oligomerization, was dependent on rac, cdc42, and mitogen-activated protein kinase, and exhibited functional distinction from the archetypal motogenic scatter factors hepatocyte growth factor and macrophage stimulatory protein. The motility-inducing and mitogen-activated protein kinase-stimulating activities of c18 NC1 were blocked by its physiologic cleavage product ES monomer, consistent with a proteolysis-dependent negative feedback mechanism. These data indicate that the collagen XVIII NC1 region encodes a motogen strictly requiring ES domain oligomerization and suggest a previously unsuspected mechanism for ECM regulation of motility and morphogenesis.
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Affiliation(s)
- C J Kuo
- Department of Surgery, Children's Hospital, Harvard Medical School, Boston. Massachusetts 02115, USA.
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Beecken WD, Fernandez A, Joussen AM, Achilles EG, Flynn E, Lo KM, Gillies SD, Javaherian K, Folkman J, Shing Y. Effect of antiangiogenic therapy on slowly growing, poorly vascularized tumors in mice. J Natl Cancer Inst 2001; 93:382-7. [PMID: 11238700 DOI: 10.1093/jnci/93.5.382] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Angiogenesis is essential for tumor growth and progression. Therefore, inhibition of angiogenesis is being studied as a new anticancer therapy. Because cytotoxic chemotherapy is more effective on rapidly growing tumors than on slowly growing tumors, it has been assumed that antiangiogenic therapy will also be effective only on rapidly growing, highly vascularized tumors. We compared the effects of two angiogenesis inhibitors, TNP-470 and angiostatin, on slowly growing, poorly vascularized and rapidly growing, highly vascularized human tumors in mice. METHODS Slowly growing (RT-4) and rapidly growing (MGH-U1) human bladder carcinoma cell lines were grown in severe combined immunodeficiency mice. Established tumors were treated with one of the two angiogenesis inhibitors. Tumor volumes, vascularity, and proliferation indices were determined. The in vitro effects of TNP-470 and of angiostatin on the proliferation of RT-4 and MGH-U1 cells were also investigated. All statistical tests were two-sided. RESULTS RT-4 and MGH-U1 tumor growth was statistically significantly inhibited by both angiogenesis inhibitors (P<.001). Both inhibitors decreased the blood vessel density in both tumor types but did not alter the in vivo proliferation indices of the tumors. TNP-470, but not angiostatin, marginally decreased the in vitro proliferation of MGH-U1 cells. CONCLUSION Slowly growing, poorly vascularized tumors in animal models respond as well as rapidly growing, highly vascularized tumors to therapy with the angiogenesis inhibitors TNP-470 and angiostatin.
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Affiliation(s)
- W D Beecken
- Department of Surgery, Children's Hospital, and Harvard Medical School, Boston, MA, USA
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11
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Lo KM, Ng SW. Bis[1,1,3,3-tetrabutyl-1,3-bis(2,3-diphenylquinoxaline-6-carboxylato)-1,3-distannoxane]. Acta Crystallogr C 1999. [DOI: 10.1107/s010827019909839x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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12
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Ryan SP, DelPrete SA, Weinstein PW, Erichson RB, Bar MH, Lo KM, Cohen NS, Tepler I. Low-dose vincristine-associated bilateral vocal cord paralysis. Conn Med 1999; 63:583-4. [PMID: 10578547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
BACKGROUND Vincristine-associated peripheral neuropathy is a well-described entity. We describe a case of vincristine-induced vocal cord paralysis, which is a rare complication of this drug. We report herein the second case of bilateral vocal cord paralysis in a patient receiving conventional doses of vincristine. OBJECTIVE To present a case report of vincristine-associated vocal cord paralysis and to review the relevant English language literature on this subject. DESIGN Report and review of the literature. SETTING Outpatient community cancer center. PATIENT A 58-year-old female with a diffuse large cell lymphoma stage IV receiving cyclophosphamide, doxorubicin, vincristine, and prednisone. RESULTS Bilateral vocal cord paralysis occurred in this patient receiving vincristine as part of her chemotherapy regimen. In addition to this case there have been a total of 25 prior reports, which are reviewed in the text. CONCLUSION The incidence of bilateral vocal cord paralysis in patients receiving vincristine on the usual low-dose schedule is low. Prompt withdrawal of the offending agent results in prompt recovery without untoward long-lasting sequela.
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Affiliation(s)
- S P Ryan
- Carl and Dorothy Bennett Cancer Center, Stamford Hospital, USA
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Lo KM, Kumar Das VG, Ng SW. Di-μ-chloro-bis(aquachlorodimethyltin)–dichlorodimethyl[2,4,6-tris(2-pyridyl)-1,3,5-triazine]tin (1/2). Acta Crystallogr C 1999. [DOI: 10.1107/s0108270199004928] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Lo KM, Kumar Das VG, Ng SW. Triphenyltin N, N-dimethylthiocarbamoylacetate, triphenyltin N, N-pentamethylenecarbamoylthioacetate and cyclopentyldiphenyltin N, N-dimethylthiocarbamoylacetate. Acta Crystallogr C 1999. [DOI: 10.1107/s0108270199001286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Lo KM, Kumar Das VG, Ng SW, Hook JM. catena-Poly[triphenyltin-μ-(N,N-diethylthiocarbamoylthioacetato-O:O')],catena-poly[triphenyltin-μ-(N-methyl-N-phenylthiocarbamoylthioacetato-O:O')] and triphenyl(N,N-tetramethylenethiocarbamoylthioacetato-O)tin. Acta Crystallogr C 1999. [DOI: 10.1107/s0108270199002954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Gillies SD, Lan Y, Lo KM, Super M, Wesolowski J. Improving the efficacy of antibody-interleukin 2 fusion proteins by reducing their interaction with Fc receptors. Cancer Res 1999; 59:2159-66. [PMID: 10232603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Fusion proteins between whole antibodies (Abs) and cytokines (immunocytokines) such as interleukin 2 have shown efficacy in several mouse tumor models despite a circulating half-life that is significantly shorter than that of the original Ab. We have examined the potential mechanisms responsible for clearance and shown that an important factor is enhanced binding to Fc receptor (FcR). Improvements in the half-lives of two different immunocytokines were made by changing the isotype of the human heavy chain C region from IgG1 or IgG3 to those with reduced binding to FcR, e.g., IgG4. The same effect could also be achieved through site-directed mutagenesis of the FcR binding site in the IgG1 H chain. In vitro studies using mouse J774 FcR-expressing cells showed increased binding of interleukin 2-based immunocytokines, relative to their corresponding Abs, and that this was reversed in those fusion proteins made with IgG4 or mutated IgG1 H chains. All of the fusion proteins showing reduced FcR binding also had reduced Ab-dependent cellular cytotoxicity activity, as measured in 4-h chromium release assays. A complete loss of complement-dependent cytotoxicity activity was seen with an IgG4-based immunocytokine derived from an IgG1 Ab with potent activity. Despite these reduced effector functions, the IgG4-based immunocytokines with extended circulating half-lives showed equivalent (in the case of severe combined immunodeficiency mouse xenograft models) or better (in the case of syngeneic models) efficacy in mouse tumor models than the original IgG1-based molecules. These novel immunocytokines may show improved efficacy in therapeutic situations where T cell- rather than natural killer- or complement-mediated antitumor mechanisms are involved.
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MESH Headings
- Animals
- Antibody-Dependent Cell Cytotoxicity
- Binding Sites
- Carcinoma/pathology
- Carcinoma/therapy
- Complement System Proteins/immunology
- Cytotoxicity, Immunologic
- Genes, Immunoglobulin
- Humans
- Immunoconjugates/metabolism
- Immunoconjugates/pharmacokinetics
- Immunoconjugates/therapeutic use
- Immunoglobulin G/genetics
- Immunoglobulin G/metabolism
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/metabolism
- Immunoglobulin Isotypes/metabolism
- Interleukin-2/genetics
- Interleukin-2/metabolism
- Kidney Neoplasms/pathology
- Male
- Melanoma, Experimental/pathology
- Melanoma, Experimental/therapy
- Metabolic Clearance Rate
- Mice
- Mice, Inbred BALB C
- Mice, SCID
- Mutagenesis, Site-Directed
- Prostatic Neoplasms/pathology
- Receptors, Fc/metabolism
- Recombinant Fusion Proteins/metabolism
- Recombinant Fusion Proteins/pharmacokinetics
- Recombinant Fusion Proteins/therapeutic use
- Tissue Distribution
- Transfection
- Transplantation, Heterologous
- Tumor Cells, Cultured
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Affiliation(s)
- S D Gillies
- Lexigen Pharmaceuticals Corporation, Lexington, Massachusetts 02421-3125, USA.
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Bao S, Chang MS, Auclair D, Sun Y, Wang Y, Wong WK, Zhang J, Liu Y, Qian X, Sutherland R, Magi-Galluzi C, Weisberg E, Cheng EY, Hao L, Sasaki H, Campbell MS, Kraeft SK, Loda M, Lo KM, Chen LB. HRad17, a human homologue of the Schizosaccharomyces pombe checkpoint gene rad17, is overexpressed in colon carcinoma. Cancer Res 1999; 59:2023-8. [PMID: 10232579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Using the palindromic PCR-cDNA display method, we have cloned a novel gene overexpressed by human colon carcinoma relative to normal colon. Among normal tissues examined, only testis expresses it at a high level. Sequence analysis revealed its extensive homology with checkpoint genes rad17 of Schizosaccharomyces pombe and RAD24 of Saccharomyces cerevisiae. This novel gene designated as hRad17 is localized to chromosome 5q12,13.1, a region known to be deleted in a variety of human cancers. Promoter region and one pseudogene of hRad17 have been identified. Whereas the increased expression of hRad17 by human colon carcinomas may be related to the known resistance of these cells to DNA-damaging agents during therapy, the deletion of hRad17 in a variety of cancers may predispose them to increased rate of mutation and heightened sensitivity to DNA-damaging agents, including radiation and anticancer drugs.
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Affiliation(s)
- S Bao
- Dana-Farber Cancer Institute, and Harvard Medical School, Boston, Massachusetts 02115, USA
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Abstract
Solid tumors depend on angiogenesis for their growth. In a transgenic mouse model of pancreatic islet cell carcinogenesis (RIP1-Tag2), an angiogenic switch occurs in premalignant lesions, and angiogenesis persists during progression to expansive solid tumors and invasive carcinomas. RIP1-Tag2 mice were treated so as to compare the effects of four angiogenesis inhibitors at three distinct stages of disease progression. AGM-1470, angiostatin, BB-94, and endostatin each produced distinct efficacy profiles in trials aimed at preventing the angiogenic switch in premalignant lesions, intervening in the rapid expansion of small tumors, or inducing the regression of large end-stage cancers. Thus, anti-angiogenic drugs may prove most efficacious when they are targeted to specific stages of cancer.
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Affiliation(s)
- G Bergers
- Department of Biochemistry and Biophysics and Hormone Research Institute, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94143-0534, USA
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Ding YH, Javaherian K, Lo KM, Chopra R, Boehm T, Lanciotti J, Harris BA, Li Y, Shapiro R, Hohenester E, Timpl R, Folkman J, Wiley DC. Zinc-dependent dimers observed in crystals of human endostatin. Proc Natl Acad Sci U S A 1998; 95:10443-8. [PMID: 9724722 PMCID: PMC27913 DOI: 10.1073/pnas.95.18.10443] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/1998] [Indexed: 11/18/2022] Open
Abstract
The crystal structure of human endostatin reveals a zinc-binding site. Atomic absorption spectroscopy indicates that zinc is a constituent of both human and murine endostatin in solution. The human endostatin zinc site is formed by three histidines at the N terminus, residues 1, 3, and, 11, and an aspartic acid at residue 76. The N-terminal loop ordered around the zinc makes a dimeric contact in human endostatin crystals. The location of the zinc site at the amino terminus, immediately adjacent to the precursor cleavage site, suggests the possibility that the zinc may be involved in activation of the antiangiogenic activity following cleavage from the inactive collagen XVIII precursor or in the cleavage process itself.
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Affiliation(s)
- Y H Ding
- Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA
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Gillies SD, Lan Y, Wesolowski JS, Qian X, Reisfeld RA, Holden S, Super M, Lo KM. Antibody-IL-12 fusion proteins are effective in SCID mouse models of prostate and colon carcinoma metastases. J Immunol 1998; 160:6195-203. [PMID: 9637539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
IL-12 is a complex cytokine in both its structure and its range of biologic activities. Fusions of this heterodimeric molecule with an intact antitumor Ab were made to test the feasibility and efficacy of targeting IL-12 to tumors to elicit a local immune response. Fusion proteins composed of the human p35 and p40 subunits had IL-12 bioactivities that were nearly as potent on human immune cells as the rIL-12 standard, but were inactive on mouse cells. Hybrid IL-12 fusion proteins composed of mouse p35 and human p40, fused to Ab, were capable of inducing IFN-gamma, but were much less active on mouse spleen cells than a mouse IL-12 standard. Despite this relatively low activity, the hybrid fusion protein was as effective in a SCID mouse model as a fully active Ab-IL-2 fusion protein in eliminating established pulmonary metastases of CT26 colon carcinoma. Specific targeting of a human IL-12 fusion protein to metastatic prostate carcinoma xenografts was also shown to be effective in SCID mice transplanted with human lymphocyte-activated killer cells. These results demonstrate the importance of directing this potent cytokine to the tumor microenvironment and suggest an important alternative to systemic IL-12 administration or gene therapy for increasing its therapeutic index.
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Affiliation(s)
- S D Gillies
- Lexigen Pharmaceuticals Corp., Lexington, MA 02137, USA.
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Lo KM, Sudo Y, Chen J, Li Y, Lan Y, Kong SM, Chen L, An Q, Gillies SD. High level expression and secretion of Fc-X fusion proteins in mammalian cells. Protein Eng 1998; 11:495-500. [PMID: 9725629 DOI: 10.1093/protein/11.6.495] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We have developed a general expression system that enhances the production and secretion of proteins in mammalian cells. The protein of interest is expressed as a fusion to a signal peptide and the Fc fragment of immunoglobulin as the N-terminal fusion partner, which can direct the cellular processes into expressing and secreting high levels of many different types of proteins. These include secretory proteins, enzymes and soluble domains of membrane proteins, as well as nuclear and regulatory proteins. Typical expression levels of these proteins from stable cell lines ranged from several to 100 microg/ml in conditioned media. The Fc domain helps to solubilize hydrophobic proteins and provides a handle for easy detection and purification of the fusion proteins; and it can be cleaved off by treatment with protease if desired.
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Affiliation(s)
- K M Lo
- Lexigen Pharmaceuticals Corporation, Lexington, MA 02173, USA
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23
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Xiang R, Lode HN, Dolman CS, Dreier T, Varki NM, Qian X, Lo KM, Lan Y, Super M, Gillies SD, Reisfeld RA. Elimination of established murine colon carcinoma metastases by antibody-interleukin 2 fusion protein therapy. Cancer Res 1997; 57:4948-55. [PMID: 9354462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A recombinant humanized antibody-interleukin 2 fusion protein (huKS1/4-IL-2) was used to direct IL-2 to the tumor microenvironment and elicit a T cell-mediated eradication of established pulmonary and hepatic CT26-KSA colon carcinoma metastases in syngeneic BALB/c mice. This antitumor effect was specific because a fusion protein, which was nonreactive with these tumor cells, failed to exert any such effect. The efficacy of the huKS1/4-IL-2 fusion protein in eliminating metastases was documented because mixtures of monoclonal antibody huKS1/4 with recombinant human IL-2 were ineffective and, at best, only partially reduced tumor load. Two lines of evidence indicated the eradication of metastases and the absence of minimal residual disease in animals treated with the fusion protein: first, the lack of detection of CT26-KSA cells by reverse transcription-PCR, which can detect one tumor cell in 10(6) liver cells; and second, the tripling of life span. The effector mechanism involved in this tumor eradication is dependent on T cells because the IL-2-directed therapy is ineffective in T cell-deficient SCID mice. The essential effector cells were further characterized as CD8+ T cells by in vivo depletion studies. Such T cells, isolated from tumor-bearing mice after fusion protein therapy, elicited MHC class I-restricted cytotoxicity in vitro against colon carcinoma target cells. Taken together, these data indicate that fusion protein-directed IL-2 therapy induces a T cell-dependent host immune response capable of eradicating established colon cancer metastases in an animal tumor model.
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Affiliation(s)
- R Xiang
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA
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25
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Ono M, Wada Y, Wu Y, Nemori R, Jinbo Y, Wang H, Lo KM, Yamaguchi N, Brunkhorst B, Otomo H, Wesolowski J, Way JC, Itoh I, Gillies S, Chen LB. FP-21399 blocks HIV envelope protein-mediated membrane fusion and concentrates in lymph nodes. Nat Biotechnol 1997; 15:343-8. [PMID: 9094135 DOI: 10.1038/nbt0497-343] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The identification of fusin and other chemokine receptors as coreceptors for HIV-1 has renewed the interest in agents that may prevent viral entry. Polyanionic compounds such as dextran sulfate, curdian sulfate, and suramin act on the V3 loop of the viral envelope and may prevent its interaction with fusin. These agents show activity against a wide range of HIV-1 strains, but have undesirable circulating half-life, bioavailability, and toxicity. We have developed a small molecule inhibitor of HIV-1 that has several advantages over these other agents. FP-21399 is a novel compound of the bis(disulfonaphthalene) dimethoxybenzene class that blocks entry of HIV into CD4+ cells and blocks fusion of infected and noninfected CD4+ cells. This compound only weakly inhibits binding of CD4 and gp120, at concentrations much greater than are required to block viral entry. Furthermore, FP-21399 can block the interaction between gp120 and antibodies directed against the V3 loop, but does not block binding of antibodies directed against the V4 loop. Animal studies demonstrate that FP-21399 is concentrated in lymph nodes, making it a promising compound for anti-HIV therapy. In SCID mice reconstituted with human immune cells, maintenance of HIV-1 infection was blocked by a 5-day treatment with low doses of FP-21399, suggesting that lymph node accumulation may contribute to antiviral activity. Finally, attempts to generate drug-resistant virus in cell culture resulted in only weakly resistant variants with IC90 values that are much lower than concentrations of FP-21399 found in lymph nodes.
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Affiliation(s)
- M Ono
- Fuji ImmunoPharmaceuticals Corp., Lexington, MA 02173, USA
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26
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Lin CC, Lo KM, Leu CS. [The practicability of preceptorship in the curriculum of medical education]. Kaohsiung J Med Sci 1996; 12:167-73. [PMID: 8709184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Physicians who have graduated from traditional medical education curriculum focus on technological and organ system training, and are deficient in modern community health care concepts and skills. A preceptorship course integrates at various medical educational periods is one of the important goals at education reform in America. In this study, we attempt to ascertain the opinions of family physicians about the current family medicine curriculum and the practicability of preceptorship in Taiwan. The result can be a reference for future medical curriculum design. Two hundreds and thirty-five (40.8%) questionnaires were collected and analyzed. They showed most respondents were dissatisfied with the current curriculum of family medicine, and most agree that primary care physicians involvement would be helpful in producing efficient and well-qualified physicians. They suggested that preceptorship should best be first integrated in a basic knowledge course. We suggest that faculties who are responsible for curriculum design should evaluate the current curriculum and the appropriateness of preceptorship in Taiwan. Prior to the reform, faculty development and evaluation are the essential and crucial tasks.
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Affiliation(s)
- C C Lin
- Department of Family Medicine, China Medical College and Hospital, Taichung, Taiwan, Republic of China
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27
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Abstract
Several human cytokines including IL-2, GM-CSF, and tumor necrosis factors alpha and beta were engineered as fusion proteins to the carboxyl terminus of a chimeric anti-ganglioside antibody, ch14.18, and expressed in transfected hybridoma cells. All of the fusion proteins were expressed at high levels and were easily purified by affinity or ion-exchange chromatography from culture supernatants. The effect of fusion on antigen binding activity was tested and found to vary with the particular cytokine. No significant decreases in antigen binding were observed, and fusion of IL-2 had the greatest positive effect in a direct antigen binding assay. All fusion proteins maintained normal levels of biological activity except for GM-CSF, which was approximately 20% active, compared to recombinant GM-CSF produced in bacteria. The clearance of the fusion proteins was examined in normal Balb/c mice after intraperitoneal injection or in athymic (nu/nu) mice after intravenous injection and was generally quite rapid, relative to ch14.18. This was mainly due to a very rapid initial clearance rate (alpha phase) since the half-lives of the beta phase of the fusion proteins (about 30 h) were comparable to that of the free antibody (about 58 h). These results demonstrate that biologically active antibody/cytokine fusion proteins can be constructed by genetic engineering. Their relatively rapid clearance may require constant infusion rather than bolus injection in order to achieve clinical efficacy.
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Affiliation(s)
- S D Gillies
- Abbott Biotech, Inc, Needham Heights, Massachusetts 02194
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28
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Lo KM, Vivier E, Rochet N, Dehni G, Levine H, Haseltine WA, Anderson P. Infection of human natural killer (NK) cells with replication-defective human T cell leukemia virus type I provirus. Increased proliferative capacity and prolonged survival of functionally competent NK cells. J Immunol 1992; 149:4101-8. [PMID: 1460293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Human T-cell leukemia virus type I (HTLV-I) can infect a variety of human cell types, but only T lymphocytes are efficiently immortalized after HTLV-I infection. This study reports an attempt to infect and to immortalize NK cells with HTLV-I. Co-cultivation of freshly isolated NK cells with a HTLV-I-producing T cell line did not result in NK cell infection. However, NK cells activated with an anti-CD16 mAb and co-cultivated with a HTLV-I-producing T cell line were reproducibly infected by HTLV-I. HTLV-I infection was documented in NK cell lines and clones by the detection of defective integrated provirus by both Southern blot and polymerase chain reaction analysis. Although HTLV-I-infected NK cells produced viral proteins, they did not produce infectious viral particles. HTLV-I-infected NK cells were phenotypically indistinguishable from their uninfected counterparts (CD16+, CD2+, CD56+, CD3-). They also retained the ability to mediate both natural and antibody-dependent cell cytotoxicity. The IL-2-dependent proliferation of HTLV-I-infected NK cells was significantly greater than that of uninfected NK cells. The doubling time of this infected population was reduced from 9 days to 3 days, and the overall survival of the culture in the absence of restimulation was extended from 5 wk to 18 wk. Unlike T lymphocytes, HTLV-I-infected NK cells were not immortal, implying a fundamental difference between these two lymphocyte populations.
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MESH Headings
- Base Sequence
- Blotting, Western
- Cell Separation
- Cell Survival
- Cells, Cultured
- Chromosome Mapping
- Cytotoxicity Tests, Immunologic
- Cytotoxicity, Immunologic
- DNA/analysis
- Flow Cytometry
- Genes, Viral
- HTLV-I Infections/immunology
- Human T-lymphotropic virus 1/genetics
- Human T-lymphotropic virus 1/pathogenicity
- Humans
- Killer Cells, Natural/cytology
- Killer Cells, Natural/microbiology
- Molecular Sequence Data
- Polymerase Chain Reaction
- Proviruses/genetics
- Receptors, Antigen, T-Cell, gamma-delta/biosynthesis
- Receptors, IgG/physiology
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Affiliation(s)
- K M Lo
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, MA 02115
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29
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Lo KM, Vivier E, Rochet N, Dehni G, Levine H, Haseltine WA, Anderson P. Infection of human natural killer (NK) cells with replication-defective human T cell leukemia virus type I provirus. Increased proliferative capacity and prolonged survival of functionally competent NK cells. The Journal of Immunology 1992. [DOI: 10.4049/jimmunol.149.12.4101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Human T-cell leukemia virus type I (HTLV-I) can infect a variety of human cell types, but only T lymphocytes are efficiently immortalized after HTLV-I infection. This study reports an attempt to infect and to immortalize NK cells with HTLV-I. Co-cultivation of freshly isolated NK cells with a HTLV-I-producing T cell line did not result in NK cell infection. However, NK cells activated with an anti-CD16 mAb and co-cultivated with a HTLV-I-producing T cell line were reproducibly infected by HTLV-I. HTLV-I infection was documented in NK cell lines and clones by the detection of defective integrated provirus by both Southern blot and polymerase chain reaction analysis. Although HTLV-I-infected NK cells produced viral proteins, they did not produce infectious viral particles. HTLV-I-infected NK cells were phenotypically indistinguishable from their uninfected counterparts (CD16+, CD2+, CD56+, CD3-). They also retained the ability to mediate both natural and antibody-dependent cell cytotoxicity. The IL-2-dependent proliferation of HTLV-I-infected NK cells was significantly greater than that of uninfected NK cells. The doubling time of this infected population was reduced from 9 days to 3 days, and the overall survival of the culture in the absence of restimulation was extended from 5 wk to 18 wk. Unlike T lymphocytes, HTLV-I-infected NK cells were not immortal, implying a fundamental difference between these two lymphocyte populations.
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Affiliation(s)
- K M Lo
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - E Vivier
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - N Rochet
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - G Dehni
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - H Levine
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - W A Haseltine
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - P Anderson
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, MA 02115
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30
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Lo KM, Lynch CA, Gillies SD. The use of a wild-type dihydrofolate reductase-encoding cDNA as a dominant selectable marker and induction of expression by methotrexate. Gene 1992; 121:365-9. [PMID: 1446834 DOI: 10.1016/0378-1119(92)90145-f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The cDNA (DHFR) encoding the wild-type (wt) dihydrofolate reductase (DHFR) was used as a dominant selectable marker in the transfection of murine hybridoma Sp2/0-Ag14 cells by protoplast fusion. The initial clones contained 100-400 copies of integrated plasmid DNA, and the high level of wt DHFR protein produced enabled the cells to survive the drug selection at 100 nM methotrexate (MTX). The expression of the gene of interest was several fold higher than when the mutant DHFR with decreased MTX binding was used as the selection marker, presumably because the clones were more sensitive to the stress induced by MTX. When the clones were propagated at higher concentrations of MTX, expression of both DHFR and the gene of interest increased. This induction is freely reversible, and we have shown that it is controlled at the transcriptional level, by nuclear run-off transcription assays.
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Affiliation(s)
- K M Lo
- Abbott Biotech Inc., Needham Heights MA 02194
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31
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32
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Lo KM, Biasolo MA, Dehni G, Palú G, Haseltine WA. Inhibition of replication of HIV-1 by retroviral vectors expressing tat-antisense and anti-tat ribozyme RNA. Virology 1992; 190:176-83. [PMID: 1529527 DOI: 10.1016/0042-6822(92)91203-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A ribozyme was constructed that specifically cleaves RNA that contains the first coding exon of the tat gene of HIV-1. This anti-tat ribozyme was incorporated into a Moloney murine leukemia virus vector. A sequence containing only the 48-nucleotide antisense region of the ribozyme was also inserted into the retroviral vector. Human T-cell lines constitutively producing the tat-antisense and the anti-tat ribozyme RNA were created by transduction into Jurkat cells. When challenged with HIV-1, both the tat-antisense and anti-tat ribozyme-producing cells inhibited the replication of HIV-1. The antisense vector conferred a greater resistance to HIV-1 replication than did the anti-tat ribozyme vector.
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Affiliation(s)
- K M Lo
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115
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33
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Lo KM, Roy A, Foley SF, Coll JT, Gillies SD. Expression and secretion of an assembled tetrameric CH2-deleted antibody in E. coli. Hum Antibodies Hybridomas 1992; 3:123-8. [PMID: 1391661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have expressed in E. coli a functional assembled antibody variant that is secreted into the media. The antibody variant is a CH2-deleted chimeric antibody 14.18, which was previously shown to be a potentially useful reagent for radioimmunodetection of human tumors. The bacterial expression vector contains a dicistronic unit comprised of a L-chain cDNA and a CH2-deleted H-chain cDNA. For translocation across the bacterial membranes, we have replaced the natural signal peptides of the H and L chains with the signal peptide of the bacterial protein pectate lyase B. When expressed in the JM105 host under the control of the trp-lac promoter, the products were secreted into the M9 growth media to about 350 micrograms/L. The secreted antibody, which can be readily purified from the media without any denaturation or renaturation steps, retains antigen-binding activity. SDS-PAGE and nondenaturing size exclusion high-pressure liquid chromatography showed that it is a mixture of assembled HL and fully assembled H2L2. In H2L2, inter-H chain disulfide bonds are not formed, and the two HL half-molecules are likely held together by the trans interaction between the two CH3 domains.
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Affiliation(s)
- K M Lo
- Abbott Biotech, Inc., Needham Heights, MA
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34
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Abstract
A genetically engineered fusion protein consisting of a chimeric anti-ganglioside GD2 antibody (ch14.18) and interleukin 2 (IL2) was tested for its ability to enhance the killing of autologous GD2-expressing melanoma target cells by a tumor-infiltrating lymphocyte line (660 TIL). The fusion of IL2 to the carboxyl terminus of the immunoglobulin heavy chain did not reduce IL2 activity as measured in a standard proliferation assay using either mouse or human T-cell lines. Antigen-binding activity was greater than that of the native chimeric antibody. The ability of resting 660 TIL cells to kill their autologous GD2-positive target cells was enhanced if the target cells were first coated with the fusion protein. This stimulation of killing was greater than that of uncoated cells in the presence of equivalent or higher concentrations of free IL2. Such antibody-cytokine fusion proteins may prove useful in targeting the biological effect of IL2 and other cytokines to tumor cells and in this way stimulate their immune destruction.
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Affiliation(s)
- S D Gillies
- Research Department, Abbott Biotech, Inc., Needham Heights, MA 02194
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35
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Gillies SD, Young D, Lo KM, Foley SF, Reisfeld RA. Expression of genetically engineered immunoconjugates of lymphotoxin and a chimeric anti-ganglioside GD2 antibody. Hybridoma (Larchmt) 1991; 10:347-56. [PMID: 1916847 DOI: 10.1089/hyb.1991.10.347] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Human lymphotoxin was genetically conjugated to the constant region of a human gamma 1 immunoglobulin gene at the end of either the second (CH2-LT) or third (CH3-LT) constant region domain. The altered heavy chain constant regions were combined in a plasmid vector together with the variable regions of a mouse anti-ganglioside GD2 antibody 14.18 and the human kappa constant region. The resulting immunoconjugate constructs were expressed in transfected hybridoma cells and tested for both their antibody and lymphotoxin activities. The two constructs were assembled to varying degrees depending on whether the third heavy chain constant region was present. Both forms retained their ability to bind antigen and mediate ADCC but only CH3-LT was able to mediate the lysis of melanoma target cells in the presence of human complement. Lymphotoxin activity, as defined in a cytolytic assay with mouse fibroblasts, was found to increase significantly as a function of heavy chain assembly and to be equivalent to unconjugated lymphotoxin. Neither of the constructs were cytotoxic for antigen-bearing melanoma cells that are normally resistant to lymphotoxin and tumor necrosis factor alpha. Such immunoconjugates may prove useful in targeting cytokines to the site of antigen-bearing cells in vivo. In this case, as a means of eliciting an inflammatory response at the site of a solid tumor.
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Affiliation(s)
- S D Gillies
- Research Department, Abbott Biotech, Needham Heights, Massachusetts 02194
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36
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Lo KM, Gillies SD. High level expression of human proteins in murine hybridoma cells: induction by methotrexate in the absence of gene amplification. Biochim Biophys Acta 1991; 1088:217-24. [PMID: 1672095 DOI: 10.1016/0167-4781(91)90057-s] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have developed an inducible system for high level expression of heterologous genes in murine hybridoma cells. The rapid induction by methotrexate (MTX) does not involve gene amplification and is controlled at the level of mRNA accumulation. Transfection was achieved by protoplast fusion with an expression vector containing the cDNA of interest and a marker gene encoding dihydrofolate reductase. The initial clones, selected at 100 nM MTX, produced high levels of the protein of interest and contained about 100-400 copies of the integrated plasmid DNA. They could adapt to a 100- to 1000-fold stepwise increase in MTX concentration in a few weeks, during which the expression of the gene of interest but not its copy number, increased several-fold. Furthermore, the induction is freely reversible. If cells were propagated in MTX-free media, the expression level decreased, but the cells could be reinduced to their original high level of expression by adding MTX back to the media. A several-fold increase in the mRNA levels of the dihydrofolate reductase and the gene of interest could be detected after induction for 18 h.
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Affiliation(s)
- K M Lo
- Abbott Biotech, Inc., Needham Heights, MA 02194
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37
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Gillies SD, Wesolowski JS, Lo KM. Targeting human cytotoxic T lymphocytes to kill heterologous epidermal growth factor receptor-bearing tumor cells. Tumor-infiltrating lymphocyte/hormone receptor/recombinant antibody. The Journal of Immunology 1991. [DOI: 10.4049/jimmunol.146.3.1067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
A genetically engineered conjugate between an anti-CD3 antibody and epidermal growth factor (EGF) was tested for its ability to mediate the lysis of receptor-bearing cells by human CTL. This construct was made by fusing an EGF coding sequence to the 3' end of the human gamma-1 H chain gene sequence and expressing the modified gene in transfected cells together with the V regions of a mouse antibody specific for the human T cell marker, CD3. The resulting conjugate was able to compete with EGF for its receptor and, at extremely low concentrations, was able to mediate the lysis of receptor-bearing tumor targets by a tumor-infiltrating lymphocytes line or by a CTL line established from peripheral blood. The construction of such conjugates by genetic engineering represents a general approach to the direct expression of highly specific hetero-bifunctional reagents without the necessity of further in vitro manipulations.
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Affiliation(s)
- S D Gillies
- Abbott Biotech, Inc., Needham Heights, MA 02194
| | | | - K M Lo
- Abbott Biotech, Inc., Needham Heights, MA 02194
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38
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Gillies SD, Wesolowski JS, Lo KM. Targeting human cytotoxic T lymphocytes to kill heterologous epidermal growth factor receptor-bearing tumor cells. Tumor-infiltrating lymphocyte/hormone receptor/recombinant antibody. J Immunol 1991; 146:1067-71. [PMID: 1824849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A genetically engineered conjugate between an anti-CD3 antibody and epidermal growth factor (EGF) was tested for its ability to mediate the lysis of receptor-bearing cells by human CTL. This construct was made by fusing an EGF coding sequence to the 3' end of the human gamma-1 H chain gene sequence and expressing the modified gene in transfected cells together with the V regions of a mouse antibody specific for the human T cell marker, CD3. The resulting conjugate was able to compete with EGF for its receptor and, at extremely low concentrations, was able to mediate the lysis of receptor-bearing tumor targets by a tumor-infiltrating lymphocytes line or by a CTL line established from peripheral blood. The construction of such conjugates by genetic engineering represents a general approach to the direct expression of highly specific hetero-bifunctional reagents without the necessity of further in vitro manipulations.
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MESH Headings
- Animals
- Antibodies, Monoclonal/genetics
- Antibodies, Monoclonal/immunology
- Antigens, Differentiation, T-Lymphocyte/immunology
- CD3 Complex
- Cytotoxicity, Immunologic
- Epidermal Growth Factor/genetics
- Epidermal Growth Factor/pharmacology
- ErbB Receptors/analysis
- Humans
- Lymphocytes, Tumor-Infiltrating/immunology
- Mice
- Receptors, Antigen, T-Cell/immunology
- Recombinant Proteins/analysis
- Recombinant Proteins/pharmacology
- T-Lymphocytes, Cytotoxic/immunology
- Tumor Cells, Cultured
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Affiliation(s)
- S D Gillies
- Abbott Biotech, Inc., Needham Heights, MA 02194
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39
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Abstract
A rapid and generally applicable method for the modification of immunoglobulin cDNAs was developed so that the variable (V) regions could be expressed as cassettes, together with a variety of constant regions. Murine cDNAs were isolated, sequenced and the V regions joined to short oligonucleotides providing both splice donor sites and unique restriction sites for insertion into an expression vector. Using this strategy we have expressed the V regions of several murine antibodies, together with the human gamma 1 constant region. Although most of these chimeric antibodies were readily expressed, one murine light-chain cDNA sequence could not be expressed in transfected hybridoma cells. Reconstruction experiments indicate that the sequence created by the fusion of the murine leader and variable region blocked expression at the level of RNA accumulation. The methods described, as well as the potential problems of expression, are applicable to both traditional cDNA fragments and those obtained by in vitro amplification techniques.
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Affiliation(s)
- S D Gillies
- Damon Biotech, Inc., Needham Heights, MA 02194
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40
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41
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Abstract
The transforming activity of naturally arising ras oncogenes results from point mutations that affect residue 12 or 61 of the encoded 21-kilodalton protein (p21). By use of site-directed mutagenesis, we showed that deletions and insertions of amino acid residues in the region of residue 12 are also effective in conferring oncogenic activity on p21. Common to these various alterations is the disruption that they create in this domain of the protein, which we propose results in the inactivation of a normal function of the protein.
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42
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43
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Profy AT, Lo KM, Usher DA. Synthesis of 2'(3')-O-DL-alanyl hexainosinic acid using T4 RNA ligase: suppression of the enzymic reverse transfer reaction by alkaline phosphatase. Nucleic Acids Res 1983; 11:1617-32. [PMID: 6857753 PMCID: PMC325820 DOI: 10.1093/nar/11.5.1617] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
2'(3')-O-DL-Alanyl (Ip)5I was synthesized by a new method. An alanine ortho ester of inosine 5'-phosphate was added to (Ip)4I using the ATP-independent reaction of T4 RNA ligase, and the product was converted smoothly to the desired ester. The enzymic reverse transfer reaction was conveniently suppressed by the dephosphorylation of the adenosine 5'-phosphate coproduct, catalyzed in situ by alkaline phosphatase.
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44
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Dunn RJ, Hackett NR, Huang KS, Jones S, Khorana HG, Lee DS, Liao MJ, Lo KM, McCoy J, Noguchi S. Studies on the light-transducing pigment bacteriorhodopsin. Cold Spring Harb Symp Quant Biol 1983; 48 Pt 2:853-62. [PMID: 6327180 DOI: 10.1101/sqb.1983.048.01.088] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Franklin WA, Lo KM, Haseltine WA. Alkaline lability of fluorescent photoproducts produced in ultraviolet light-irradiated DNA. J Biol Chem 1982; 257:13535-43. [PMID: 7142164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Ultraviolet light induces alkaline labile lesions in DNA. These lesions occur at the bipyrimidine sites T-C, C-C, and T-T, and do not result from the formation of pyrimidine cyclobutane dimers. To examine the chemical nature of the alkaline labile lesions, pyrimidine dinucleotides (2'-deoxythymidylyl-(3' leads to 5')-2'-deoxycytidine, 2'-deoxythymidylyl-(3' leads to 5')-2'-deoxythymidine, 2'-deoxycytidylyl-(3' leads to 5')-2-deoxycytidine, and 2'-deoxycytidylyl-(3' leads to 5')-2'-deoxythymidine) were used as a model system. Ultraviolet light irradiation of all four dinucleotides resulted in the formation of substantial quantities (relative to cyclobutane pyrimidine dimers) of products that were red-shifted in UV absorbance and fluorescent. These products are identified as precursors to the 6-4'-[pyrimidin-2'-one]-pyrimidine class of products that have been previously shown to occur in UV-irradiated DNA. The fluorescent products were found to be alkaline labile; the products contained a 3'-phosphate end group after alkali treatment. Two of the fluorescent products have been found in enzymatic digests of high dose UV-irradiated salmon sperm DNA, the T-C and T-T UV-induced products. The relative rates of formation of these products in 32P-radiolabeled dinucleotides were measured. We conclude that the alkaline labile lesions observed in DNA at the bipyrimidine sites are the same as those that yield the 6-4 products upon acid hydrolysis of DNA. The mechanisms for the formation and the consequences of DNA structure for these lesions as well as the possible biological significance of this class of UV damage are discussed.
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Haseltine WA, Gordon LK, Lindan C, Lippke J, Brash D, Lo KM, Royer-Pokora B. New approaches to DNA damage and repair: the ultraviolet light example. Basic Life Sci 1982; 20:315-322. [PMID: 7115270 DOI: 10.1007/978-1-4613-3476-7_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
DNA fragments of defined sequence are used as probes to study DNA damage and repair. The case of ultraviolet light is presented and includes the following: (a) Description of the distribution of cyclobutane pyrimidine dimers within defined DNA sequences. Considerations of the effect of neighboring base composition, dose rate, and double- or single-stranded property of the DNA are discussed. (b) Dissection of the anatomy of the incision event and subsequent repair steps. A three-step incision model for repair of cyclobutane dimers by the Micrococcus luteus repair enzymes will be presented. The steps are (1) recognition of the lesion and N-glycosylase scission, (2) cleavage of the phosphodiester bond 3' to the newly created apyrimidinic site, and (3) scission of the apyrimidinic sugar on the 5' side. (c) Use of human alphoid sequences as indicators of DNA damage in intact human cells. (d) Biological significance of a novel ultraviolet light-induced photoproduct. This photoproduct occurs at pyrimidine-cytosine sequences and may have a significant biological role.
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