Human Lactoferrin Stimulates Thymidine Incorporation into DNA of Rat Crypt Cells

Nichols, Buford L.; McKee, Kathryn S.; Henry, J. E.; Putman, Margaret

doi:10.1203/00006450-198706000-00011

Cited by 144 publications

(65 citation statements)

References 25 publications

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“…The effects of LF in vitro are varied. In most cases, LF is stimulatory (20)(21)(22)(23); however, in some cases, LF is inhibitory (24). The effect of LF in vivo also has been studied.…”

mentioning

confidence: 99%

Identification of an alternative form of human lactoferrin mRNA that is expressed differentially in normal tissues and tumor-derived cell lines

Siebert

Huang

1997

Proc. Natl. Acad. Sci. U.S.A.

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Lactoferrin (LF), traditionally known as an iron-binding protein present in high concentrations in milk and various secretions, has emerged as a multifunctional protein involved in many aspects of the host defense against infection. Recently, LF has been shown to inhibit the growth of solid tumors and reduce experimental metastasis in mice, suggesting that LF also may play a role in the defense against tumorigenesis. Here we provide the sequence of the cDNA and promoter region, the chromosome assignment, and tissue expression pattern of a novel form of LF mRNA (⌬LF). The sequence of ⌬LF mRNA is nearly identical to that of LF mRNA; however, at the 5 end, we find a novel sequence that replaces the N-terminal signal peptide sequence of LF mRNA. We map the ⌬LF mRNA to human chromosome 3 and find that both ⌬LF and LF sequences colocalize to the same cloned 90-to 150-kb genomic DNA fragment. We further show that the ⌬LF mRNA is the product of alternative splicing of the LF gene and likely is specified by use of an alternative promoter. Although we find ⌬LF mRNA at various levels in 20 of 20 adult and fetal human tissues, we do not find ⌬LF mRNA in any of 14 diverse tumor-derived cell lines.

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“…The effects of LF in vitro are varied. In most cases, LF is stimulatory (20)(21)(22)(23); however, in some cases, LF is inhibitory (24). The effect of LF in vivo also has been studied.…”

mentioning

confidence: 99%

Identification of an alternative form of human lactoferrin mRNA that is expressed differentially in normal tissues and tumor-derived cell lines

Siebert

Huang

1997

Proc. Natl. Acad. Sci. U.S.A.

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“…2) The multifunctional LF protein exhibits a wide variety of activities including immunomodulation, 3) iron binding, 4) anti-microbial, 5) anti-inflammatory, 6,7) cell proliferation 8) and anti-oxidation. 9) This multitude of biological activities has created great interest in the use of LF in drug discovery.…”

mentioning

confidence: 99%

The pH-Dependent Formation of PEGylated Bovine Lactoferrin by Branched Polyethylene Glycol (PEG)-N-Hydroxysuccinimide (NHS) Active Esters

Nojima

Iguchi

Suzuki

et al. 2009

Biological & Pharmaceutical Bulletin

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Lactoferrin (LF) is an 80-kDa member of the transferrin family of iron-binding glycoproteins and is found in various biological fluids, especially milk.2) The multifunctional LF protein exhibits a wide variety of activities including immunomodulation, 3) iron binding, 4) anti-microbial, 5) anti-inflammatory, 6,7) cell proliferation 8) and anti-oxidation. 9) This multitude of biological activities has created great interest in the use of LF in drug discovery.10) Recently, we have developed PEGylated LF with high biological activities and enhanced pharmacokinetics properties.11) PEGylation refers to the modification of biological molecules by the linking of one or more polyethylene glycol (PEG) groups. This approach is utilized in many pharmaceutical and biotechnical applications. 12,13) N-Hydroxysuccinimide (NHS) active esters of PEG (PEG-NHS) are frequently used for the amino group modification of target proteins. NHS activated esters produce stable amide linkages between PEG and primary amines such as N-terminal a-amine and lysine e-amine residues. PEG-NHS typically couples to the free amino group of the targeted protein at physiological pH, ranging from pH 7 to 9. NHS active esters are known to possess highly hydrolytic activities under basic conditions. Although bioconjugation by NHS active esters is generally considered to be the mechanism of PEGylation, detailed reports of actual PEGylated reactions by NHS active esters are rare. Thus, the aim of this study was to investigate the kinetics of the conjugation reaction between branched PEG-NHS and bovine lactoferrin (bLF), focusing on pH dependency. The present investigation demonstrates the importance of the pH values in the PEGylated reactions. MATERIALS AND METHODSpH-Dependent PEGylation of Bovine Lactoferrin (bLF) PEGylated reaction mixtures contained bLF (MG nutritionals, Melbourne, Australia) and branched 40-kDa PEG-NHS reagent (SUNBRIGHT GL2-400GS2, NOF Corporation, Tokyo, Japan) at a 1 : 10 molar ratio. Reaction mixtures were dissolved in the following buffers at the indicated pH: 50 mM acetate buffer (pH 4.0, 5.0); 50 mM phosphate buffer (pH 6.0, 7.0, 8.0); or 50 mM borate buffer (pH 9.0). The final bLF concentration was 0.5 mg/ml. Reactions were carried out for 1 h at 25°C and stopped by the addition of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) loading buffer. The reaction mixtures were then subjected to 7.5% SDS-PAGE under non-reducing conditions and visualized by Coomassie Brilliant Blue (CBB) staining. Conjugation Reaction Kinetics in Buffers of Different pH ValuesTwo kinds of branched PEG-NHS with average molecular weights of 20 kDa (SUNBRIGHT GL2-200GS2, NOF Corporation, Tokyo, Japan) or 40 kDa (see above) were used. Conjugation reactions were carried out as described above except that the incubation time was 24 h, and the buffers used were phosphate-buffered saline (PBS, pH 7.4), 50 mM borate (pH 9.0) and Good's buffers (BICINE, CHES and TAPS, pH 9.0). Reaction samples (corresponding to 2 mg bLF) were taken at indicat...

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“…Lactoferrin is also found in organs of reproduction such as mammary glands (197) and the uterus (198,199). The known biological functions of lactoferrin are the stimulation of DNA synthesis (200), the transport of iron through the fetal intestine (201), the modulation of the immune system (202,203), and bacteriostatic/bactericidal activities by chelating iron (204). Lactoferrin is believed to play a role in the uterus by one or more of the following mechanisms: as an iron reservoir (205), by maintaining uterine proliferation (206), by tissue remodeling through its intrinsic RNase activity (207)(208)(209), or by fighting infections through its bacteriostatic (194) and bacteriocidal (204) activities.…”

Section: Altered Steroid Hormone Homeostasis In Fishmentioning

confidence: 99%

Chronic Toxicity of Environmental Contaminants: Sentinels and Biomarkers

LeBlanc¹,

Bain²

1997

Environmental Health Perspectives

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Due to the use of a limited number of species and subchronic exposures, current ecological hazard assessment processes can underestimate the chronic toxicity of environmental contaminants resulting in adverse responses of sentinel species. Several incidences where sentinel species have responded to the effects of chronic exposure to ambient levels of environmental contaminants are discussed, including the development of neoplasia in fish, immunosuppression in marine mammals, pseudohermaphrodism in invertebrates, teratogenicity in amphibians, and aberrations in the sexual development of fish and reptiles. Biomarkers of chronic toxicity, including DNA mutations, alterations in specific protein and mRNA levels, and perturbations in metabolism, are presented. The incorporation of appropriate surrogate species and biomarkers of chronic toxicity into standard toxicity characterizations is proposed as a means of significantly refining the ecological hazard assessment process. -Environ Health Perspect 105(Suppl 1): 65-80 (1997)

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Human Lactoferrin Stimulates Thymidine Incorporation into DNA of Rat Crypt Cells

Cited by 144 publications

References 25 publications

Identification of an alternative form of human lactoferrin mRNA that is expressed differentially in normal tissues and tumor-derived cell lines

Identification of an alternative form of human lactoferrin mRNA that is expressed differentially in normal tissues and tumor-derived cell lines

The pH-Dependent Formation of PEGylated Bovine Lactoferrin by Branched Polyethylene Glycol (PEG)-N-Hydroxysuccinimide (NHS) Active Esters

Chronic Toxicity of Environmental Contaminants: Sentinels and Biomarkers

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