Possible chemopreventive effects of bovine lactoferrin on esophagus and lung carcinogenesis in the rat

Chemopreventive Potential of Phyllanthus emblica Fruit Extract against Colon and Liver Cancer Using a Dual-Organ Rat Carcinogenesis Model

Humans are frequently exposed to various carcinogens capable of inducing cancer in multiple organs. Phyllanthus emblica (P. emblica) is known for its strong antioxidant properties and potential in cancer prevention. However, its effectiveness against combined carcinogens remains relatively unexplored. This study aimed to assess the chemopreventive potential of the ethanolic extract of P. emblica fruits against preneoplastic lesions in the liver and colon using a rat model. Rats were administered with diethylnitrosamine (DEN) and 1,2-dimethylhydrazine (DMH) to induce hepato- and colon carcinogenesis, respectively. The ethanolic extract of P. emblica fruit at 100 and 500 mg/kg bw significantly reduced the number of preneoplastic lesions in the liver by 74.7% and 55.6%, respectively, and in the colon by 39.2% and 40.8%, respectively. Similarly, the extract decreased the size of preneoplastic lesions in the liver by 75.2% (100 mg/kg bw) and 70.6% (500 mg/kg bw). Furthermore, the extract significantly reduced the cell proliferation marker in the liver by 70.3% (100 mg/kg bw) and 61.54% (500 mg/kg bw), and in the colon by 62.7% (100 mg/kg bw) and 60.5% (500 mg/kg bw). The ethanolic extract also enhanced liver antioxidant enzyme activities and demonstrated free radical scavenging in DPPH, ABTS, and FRAP assays. Additionally, the dichloromethane fraction of P. emblica showed significant cancer prevention potential by reducing intracellular ROS and NO production by 61.7% and 35.4%, respectively, in RAW 264.7 macrophages. It also exhibited antimutagenic effects with a reduction of 54.0% against aflatoxin B1 and 52.3% against 2-amino-3,4-dimethylimidazo[4,5-f]quinoline-induced mutagenesis in Salmonella typhimurium. Finally, this study highlights the chemopreventive activity of P. emblica fruit extract against the initiation of early-stage carcinogenic lesions in the liver and colon in rats treated with dual carcinogens.

The anticancer activity of bovine lactoferrin is reduced by deglycosylation and it follows a different pathway in cervix and colon cancer cells

Bovine lactoferrin (bLF) is a glycosylated protein with purported beneficial properties. The aim of this work was to determine the role of bLF glycosylation in the adhesion, internalization, and growth inhibition of cancer cells. The viability of cervix (HeLa) and colon (Caco-2) cancer cells (MTT assay and epifluorescence microscopy) was inhibited by bLF, while deglycosylated bLF (bLFdeg) had no effect. Adhesion to cell surfaces was quantified by immunofluorescence assay and showed that bLF was able to bind more efficiently to both cell lines than bLFdeg. Microscopic observations indicated that bLF glycosylation favored bLF binding to epithelial cells and that it was endocytosed through caveolin-1-mediated internalization. In addition, the mechanism of action of bLF on cancer cell proliferation was investigated by determining the amount of phosphorylated intermediates of signaling pathways such as epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK) and protein kinase B (known as Akt). Chemoluminescence immunoassay of phosphorylated intermediates showed that bLF inhibited Akt phosphorylation, consistent with its growth inhibiting activity. This assay also indicated that the bLF receptor/signaling pathways may be different in the two cell lines, Caco-2 and HeLa. This work confirmed the effect of glycosylated bLF in inhibiting cancer cell growth and that glycosylation is required for optimal surface adhesion, internalization, and inhibition of the ERK/Akt pathway of cell proliferation through glycosylated cell surface receptors.

Production of Bioactive Porcine Lactoferrin through a Novel Glucose-Inducible Expression System in Pichia pastoris: Unveiling Antimicrobial and Anticancer Functionalities

Lactoferrin (LF) stands as one of the extensively investigated iron-binding glycoproteins within milk, exhibiting diverse biological functionalities. The global demand for LF has experienced consistent growth. Biotechnological strategies aimed at enhancing LF productivity through microbial expression systems offer substantial cost-effective advantages and exhibit fewer constraints compared to traditional animal bioreactor technologies. This study devised a novel recombinant plasmid, wherein the AOX1 promoter was replaced with a glucose-inducible G1 promoter (PG1) to govern the expression of recombinant porcine LF (rpLF) in Pichia pastoris GS115. High-copy-number PG1-rpLF yeast clones were meticulously selected, and subsequent induction with 0.05 g/L glucose demonstrated robust secretion of rpLF. Scaling up production transpired in a 5 L fermenter, yielding an estimated rpLF productivity of approximately 2.8 g/L by the conclusion of glycerol-fed fermentation. A three-step purification process involving tangential-flow ultrafiltration yielded approximately 6.55 g of rpLF crude (approximately 85% purity). Notably, exceptional purity of rpLF was achieved through sequential heparin and size-exclusion column purification. Comparatively, the present glucose-inducible system outperformed our previous methanol-induced system, which yielded a level of 87 mg/L of extracellular rpLF secretion. Furthermore, yeast-produced rpLF demonstrated affinity for ferric ions (Fe3+) and exhibited growth inhibition against various pathogenic microbes (E. coli, S. aureus, and C. albicans) and human cancer cells (A549, MDA-MB-231, and Hep3B), similar to commercial bovine LF (bLF). Intriguingly, the hydrolysate of rpLF (rpLFH) manifested heightened antimicrobial and anticancer effects compared to its intact form. In conclusion, this study presents an efficient glucose-inducible yeast expression system for large-scale production and purification of active rpLF protein with the potential for veterinary or medical applications.

Therapeutic potential of lactoferrin-coated iron oxide nanospheres for targeted hyperthermia in gastric cancer

Lactoferrin (LF) is a non-heme iron-binding glycoprotein involved in the transport of iron in blood plasma. In addition, it has many biological functions, including antibacterial, antiviral, antimicrobial, antiparasitic, and, importantly, antitumor properties. In this study, we have investigated the potential of employing lactoferrin-iron oxide nanoparticles (LF-IONPs) as a treatment modality for gastric cancer. The study confirms the formation of LF-IONPs with a spherical shape and an average size of 5 ± 2 nm, embedded within the protein matrix. FTIR and Raman analysis revealed that the Fe-O bond stabilized the protein particle interactions. Further, we conducted hyperthermia studies to ascertain whether the proposed composite can generate a sufficient rise in temperature at a low frequency. The results confirmed that we can achieve a temperature rise of about 7 °C at 242.4 kHz, which can be further harnessed for gastric cancer treatment. The particles were further tested for their anti-cancer activity on AGS cells, with and without hyperthermia. Results indicate that LF-IONPs (10 µg/ml) significantly enhance cytotoxicity, resulting in the demise of 67.75 ± 5.2% of cells post hyperthermia, while also exhibiting an inhibitory effect on cell migration compared to control cells, with the most inhibition observed after 36 h of treatment. These findings suggest the potential of LF-IONPs in targeted hyperthermia treatment of gastric cancer.

Proteins and their functionalization for finding therapeutic avenues in cancer: Current status and future prospective

Despite the remarkable advancement in the health care sector, cancer remains the second most fatal disease globally. The existing conventional cancer treatments primarily include chemotherapy, which has been associated with little to severe side effects, and radiotherapy, which is usually expensive. To overcome these problems, target-specific nanocarriers have been explored for delivering chemo drugs. However, recent reports on using a few proteins having anticancer activity and further use of them as drug carriers have generated tremendous attention for furthering the research towards cancer therapy. Biomolecules, especially proteins, have emerged as suitable alternatives in cancer treatment due to multiple favourable properties including biocompatibility, biodegradability, and structural flexibility for easy surface functionalization. Several in vitro and in vivo studies have reported that various proteins derived from animal, plant, and bacterial species, demonstrated strong cytotoxic and antiproliferative properties against malignant cells in native and their different structural conformations. Moreover, surface tunable properties of these proteins help to bind a range of anticancer drugs and target ligands, thus making them efficient delivery agents in cancer therapy. Here, we discuss various proteins obtained from common exogenous sources and how they transform into effective anticancer agents. We also comprehensively discuss the tumor-killing mechanisms of different dietary proteins such as bovine α-lactalbumin, hen egg-white lysozyme, and their conjugates. We also articulate how protein nanostructures can be used as carriers for delivering cancer drugs and theranostics, and strategies to be adopted for improving their in vivo delivery and targeting. We further discuss the FDA-approved protein-based anticancer formulations along with those in different phases of clinical trials.

p53 status modifies cytotoxic activity of lactoferrin under hypoxic conditions

Lactoferrin (LF) is an iron binding glycoprotein of the transferrin family with a wide spectrum of biological effects, including anti-cancer activity. However, the detailed molecular mechanisms of anti-cancer activity of LF have not been fully determined. In this study, we tried to clarify cytotoxic functions of LF on various cell lines under hypoxic conditions and elucidate those molecular mechanisms. Cytotoxic activity of LF on cell lines was found to have a range of sensitivities. Hypoxia decreased sensitivity to LF in KD (lip fibroblast) but increased that in HSC2 (oral squamous cell carcinoma). Expression analyses further revealed that LF treatments increased hypoxic HIF-1α, -2α and p53 proteins in KD but attenuated them in HSC2 cells, and decreased HIF-1 target gene, DEC2, in KD but increased it in HSC2, suggesting a possible relationship between LF-modified DEC2 expression and HIF-α protein. MTT assay strikingly demonstrated that cells expressing mutant-type p53 (MT5) were more sensitive to LF than control HepG2 (hepatoma), suggesting an important role of the p53 signal. Knock-down of TP53 (p53 gene) interestingly reduced sensitivity to LF in HepG2, suggesting that p53 may be a target of LF cytotoxic activity. Further analyses with a ferroptosis promoter or inhibitor demonstrated that LF increased ACSL4 in hypoxic MT5, suggesting LF-induced ferroptosis in cells expressing mutant-type p53. In conclusion, hypoxia was found to regulate cytotoxic activities of LF differently among various cell lines, possibly through the p53 signaling pathway. LF further appeared to regulate ferroptosis through a modification of ACSL4 expression.

The effectiveness of whey proteins in prevention and treatment of cancer: a review

Cancer prevalence is rising rapidly around the globe, contributing immensely to the burden on health systems, hence the search for more effective and selective treatments still remains enticing. Whey, as a natural source, has received extensive focus in recent years because of its intriguing applications to health benefits. Growing consumer appreciation of the nutraceutical effects of whey components makes them an attractive field within cancer research. Whey is a valuable source of superior-quality proteins, lactose, vitamins, and minerals that contribute to proper nutrition as well as help hamper illness and even complement certain disease-related therapy prognosis. As a result, industry leaders and dairy producers are devising new ways to valorize it. Great emphasis on cancer prevention and treatment has been given to whey protein (WP) by the scientific community. WP intake has been proven to induce anti-cancer effects in various in vitro and in vivo studies. Nutritionists and dietitians are now enormously endorsing the role of WP in the therapeutic field, notably for cancer cachexia management. However, human intervention studies with WP are in their infancy and remain to be established with different tumor entities to provide valid proof of its ability to act as a coadjuvant in cancer treatment.

Bovine Lactoferrin Induces Cell Death in Human Prostate Cancer Cells

Bovine lactoferrin (bLf) is a multifunctional protein widely associated with anticancer activity. Prostate cancer is the second most frequent type of cancer worldwide. This study was aimed at evaluating the influence of bLf on cell viability, cell cycle progression, reactive oxygen species (ROS) production, and rate of apoptosis in the human prostate cancer cell line (DU-145). MTT assay and trypan blue exclusion were used to analyze cell viability. Morphological changes were analyzed through optical microscopy after 24 h and 48 h of bLf treatment. FITC-bLf internalization and cellular damage were observed within 24 h by confocal fluorescence microscopy. Cell cycle analyses were performed by flow cytometry and propidium iodide. For caspases 3/7 activation and reactive oxygen species production evaluation, cells were live-imaged using the high-throughput system Operetta. The cell viability assays demonstrated that bLf induces cell death and morphological changes after 24 h and 48 h of treatment compared to control on DU-145 cells. The bLf internalization was detected in DU-145 cells, G₁-phase arrest of the cell cycle, caspase 3/7 activation, and increased oxidative stress on bLf-treated cells. Our data support that bLf has an important anticancer activity, thus offering new perspectives in preventing and treating prostate cancer.

Lactoferrin: A Nutraceutical with Activity against Colorectal Cancer

Homeostasis in the human body results from the tight regulation of several events, since too little inflammation disrupts the process of tissue repair and remodeling, whereas too much exerts a collateral effect by causing tissue damage with life-threatening consequences. In some clinical conditions, such as inflammatory bowel disease (IBD), inflammation functions as a double-edged sword by either enabling or inhibiting cancer development and progression. Generally, cancer develops through evasion mechanisms that regulate cell growth, causing a high rate of uncontrolled proliferation, and mechanisms for evading cell death, such as apoptosis. Moreover, chronic inflammation is a factor that contributes to colorectal cancer (CRC), as observed in individuals with IBD; all these conditions favor an increased rate of angiogenesis and eventual metastasis. Lactoferrin (Lf) is a mammalian iron-binding multifunctional glycoprotein regarded as a natural compound that up- and downregulates both humoral and cellular components of immunity involved in regulating the inflammatory response and maintaining gut homeostasis. Human and bovine Lf share high sequence homology and have very similar antimicrobial, anti-inflammatory, and immunomodulatory activities. Bovine Lf from milk is considered a safe molecule and is commercially available in large quantities. This review mainly focuses on the regulatory effects of orally administered bovine Lf on the inflammatory response associated with CRC; this approach indicates that CRC is one of the most frequently diagnosed cancers and affects the intestinal tract with high clinical and epidemiologic relevance. Thus, this review may provide foundations for the potential use of bovine Lf alone or as a natural adjunct agent to increase the effectiveness and reduce the side effects of anticancer chemotherapy.

The effect of lactoferrin in aging: role and potential

Aging is frequently accompanied by various types of physiological deterioration, which increases the risk of human pathologies. Global public health efforts to increase human lifespan have increasingly focused on lowering the risk of aging-related diseases, such as diabetes, neurodegenerative diseases, cardiovascular disease, and cancers. Dietary intervention is a promising approach to maintaining human health during aging. Lactoferrin (LF) is known for its physiologically pleiotropic properties. Anti-aging interventions of LF have proven to be safe and effective for various pharmacological activities, such as anti-oxidation, anti-cellular senescence, anti-inflammation, and anti-carcinogenic. Moreover, LF has a pivotal role in modulating the major signaling pathways that influence the longevity of organisms. Thus, LF is expected to be able to attenuate the process of aging and greatly ameliorate its effects.

Lactoferrin in the Prevention and Treatment of Intestinal Inflammatory Pathologies Associated with Colorectal Cancer Development

The connection between inflammation and cancer is well-established and supported by genetic, pharmacological and epidemiological data. The inflammatory bowel diseases (IBDs), including Crohn's disease and ulcerative colitis, have been described as important promoters for colorectal cancer development. Risk factors include environmental and food-borne mutagens, dysbalance of intestinal microbiome composition and chronic intestinal inflammation, with loss of intestinal epithelial barrier and enhanced cell proliferation rate. Therapies aimed at shutting down mucosal inflammatory response represent the foundation for IBDs treatment. However, when applied for long periods, they can alter the immune system and promote microbiome dysbiosis and carcinogenesis. Therefore, it is imperative to find new safe substances acting as both potent anti-inflammatory and anti-pathogen agents. Lactoferrin (Lf), an iron-binding glycoprotein essential in innate immunity, is generally recognized as safe and used as food supplement due to its multifunctionality. Lf possesses a wide range of immunomodulatory and anti-inflammatory properties against different aseptic and septic inflammatory pathologies, including IBDs. Moreover, Lf exerts anti-adhesive, anti-invasive and anti-survival activities against several microbial pathogens that colonize intestinal mucosa of IBDs patients. This review focuses on those activities of Lf potentially useful for the prevention/treatment of intestinal inflammatory pathologies associated with colorectal cancer development.

Lactoferrin from Bovine Milk: A Protective Companion for Life

Lactoferrin (Lf), an iron-binding multifunctional glycoprotein belonging to the transferrin family, is present in most biological secretions and reaches particularly high concentrations in colostrum and breast milk. A key function of lactoferrin is non-immune defence and it is considered to be a mediator linking innate and adaptive immune responses. Lf from bovine milk (bLf), the main Lf used in human medicine because of its easy availability, has been designated by the United States Food and Drug Administration as a food additive that is generally recognized as safe (GRAS). Among the numerous protective activities exercised by this nutraceutical protein, the most important ones demonstrated after its oral administration are: Antianemic, anti-inflammatory, antimicrobial, immunomodulatory, antioxidant and anticancer activities. All these activities underline the significance in host defence of bLf, which represents an ideal nutraceutical product both for its economic production and for its tolerance after ingestion. The purpose of this review is to summarize the most important beneficial activities demonstrated following the oral administration of bLf, trying to identify potential perspectives on its prophylactic and therapeutic applications in the future.

Lactoferrin's Anti-Cancer Properties: Safety, Selectivity, and Wide Range of Action

Despite recent advances in cancer therapy, current treatments, including radiotherapy, chemotherapy, and immunotherapy, although beneficial, present attendant side effects and long-term sequelae, usually more or less affecting quality of life of the patients. Indeed, except for most of the immunotherapeutic agents, the complete lack of selectivity between normal and cancer cells for radio- and chemotherapy can make them potential antagonists of the host anti-cancer self-defense over time. Recently, the use of nutraceuticals as natural compounds corroborating anti-cancer standard therapy is emerging as a promising tool for their relative abundance, bioavailability, safety, low-cost effectiveness, and immuno-compatibility with the host. In this review, we outlined the anti-cancer properties of Lactoferrin (Lf), an iron-binding glycoprotein of the innate immune defense. Lf shows high bioavailability after oral administration, high selectivity toward cancer cells, and a wide range of molecular targets controlling tumor proliferation, survival, migration, invasion, and metastasization. Of note, Lf is able to promote or inhibit cell proliferation and migration depending on whether it acts upon normal or cancerous cells, respectively. Importantly, Lf administration is highly tolerated and does not present significant adverse effects. Moreover, Lf can prevent development or inhibit cancer growth by boosting adaptive immune response. Finally, Lf was recently found to be an ideal carrier for chemotherapeutics, even for the treatment of brain tumors due to its ability to cross the blood-brain barrier, thus globally appearing as a promising tool for cancer prevention and treatment, especially in combination therapies.

Inhibition of DMH-DSS-induced colorectal cancer by liposomal bovine lactoferrin in rats

Bovine lactoferrin (bLF) is a multifunctional protein with anti-inflammatory, antibacterial, antiviral, anti-tumour and immunoregulatory effects. The present study was conducted to evaluate the anti-inflammatory and anti-tumour effects of liposomal bLF (LbLF) in a 1,2-dimethylhydrazine (DMH)/dextran sulphate sodium (DSS)-induced model of carcinogenesis in F344 rats. F344 rats were randomly divided into three groups: Control (water), 500 or 1,000 mg/kg/day LbLF; additionally, the rats were injected with DMH (20 mg/kg) once per week for 8 consecutive weeks, after one week of drinking water containing 1% DSS. All rats were sacrificed at 25 weeks. The tissues were examined for the presence of aberrant crypt foci (ACF) and subjected to histopathological analysis. Additionally, human colon cancer cells were utilised to investigate the effect of LbLF on proliferation and inflammation. Rats from the 500 and 1,000 mg/kg/day LbLF groups harboured significantly fewer colon ACF, adenomas and adenocarcinomas than the rats from the control group. Lastly, it was demonstrated that LbLF inhibits cell growth and TNF-α mRNA expression. These data support the hypothesis that LbLF affects colorectal carcinogenesis by suppressing inflammation and cell proliferation in rats.

A Tetrameric Peptide Derived from Bovine Lactoferricin Exhibits Specific Cytotoxic Effects against Oral Squamous-Cell Carcinoma Cell Lines

Several short linear peptides derived from cyclic bovine lactoferricin were synthesized and tested for their cytotoxic effect against the oral cavity squamous-cell carcinoma (OSCC) cell lines CAL27 and SCC15. As a control, an immortalized and nontumorigenic cell line, Het-1A, was used. Linear peptides based on the RRWQWR core sequence showed a moderate cytotoxic effect and specificity towards tumorigenic cells. A tetrameric peptide, LfcinB(20–25)₄, containing the RRWQWR motif, exhibited greater cytotoxic activity (>90%) in both OSCC cell lines compared to the linear lactoferricin peptide or the lactoferrin protein. Additionally, this tetrameric peptide showed the highest specificity towards tumorigenic cells among the tested peptides. Interestingly, this effect was very fast, with cell shrinkage, severe damage to cell membrane permeability, and lysis within one hour of treatment. Our results are consistent with a necrotic effect rather than an apoptotic one and suggest that this tetrameric peptide could be considered as a new candidate for the therapeutic treatment of OSCC.

Multifunctional iron bound lactoferrin and nanomedicinal approaches to enhance its bioactive functions

Lactoferrin (Lf), an iron-binding protein from the transferrin family has been reported to have numerous functions. Even though Lf was first isolated from milk, it is also found in most exocrine secretions and in the secondary granules of neutrophils. Antimicrobial and anti-inflammatory activity reports on lactoferrin identified its significance in host defense against infection and extreme inflammation. Anticarcinogenic reports on lactoferrin make this protein even more valuable. This review is focused on the structural configuration of iron-containing and iron-free forms of lactoferrin obtained from different sources such as goat, camel and bovine. Apart for emphasizing on the specific beneficial properties of lactoferrin from each of these sources, the general antimicrobial, immunomodulatory and anticancer activities of lactoferrin are discussed here. Implementation of nanomedicinial strategies that enhance the bioactive function of lactoferrin are also discussed, along with information on lactoferrin in clinical trials.

Iron-free and iron-saturated bovine lactoferrin inhibit survivin expression and differentially modulate apoptosis in breast cancer

BACKGROUND

Iron binding, naturally occurring protein bovine lactoferrin (bLf) has attracted attention as a safe anti-cancer agent capable of inducing apoptosis. Naturally, bLf exists partially saturated (15-20%) with Fe(3+) however, it has been demonstrated that manipulating the saturation state can enhance bLf's anti-cancer activities.

METHODS

Apo-bLf (Fe(3+) free) and Fe-bLf (>90% Fe(3+) Saturated) were therefore, tested in MDA-MB-231 and MCF-7 human breast cancer cells in terms of cytotoxicity, proliferation, migration and invasion. Annexin-V Fluos staining was also employed in addition to apoptotic protein arrays and Western blotting to determine the specific mechanism of bLf-induced apoptosis with a key focus on p53 and inhibitor of apoptosis proteins (IAP), specifically survivin.

RESULTS

Apo-bLf induced significantly greater cytotoxicity and reduction in cell proliferation in both cancer cells showing a time and dose dependent effect. Importantly, no cytotoxicity was detected in normal MCF-10-2A cells. Both forms of bLf significantly reduced cell invasion in cancer cells. Key apoptotic molecules including p53, Bcl-2 family proteins, IAP members and their inhibitors were significantly modulated by both forms of bLf, though differentially in each cell line. Most interestingly, both Apo-bLf and Fe-bLf completely inhibited the expression of survivin protein (key IAP), after 48 h at 30 and 40 nM in cancer cells.

CONCLUSIONS

The capacity of these forms of bLf to target survivin expression and modulation of apoptosis demonstrates an exciting potential for bLf as an anti-cancer therapeutic in the existing void of survivin inhibitors, with a lack of successful inhibitors in the clinical management of cancer.

Anticancer effects of lactoferrin: underlying mechanisms and future trends in cancer therapy

Lactoferrin has been widely studied over the last 70 years, and its role in diverse biological functions is now well known and generally accepted by the scientific community. Usually, alterations of the lactoferrin gene in cells are associated with an increased incidence of cancer. Several studies suggest that exogenous treatment with lactoferrin and its derivatives can efficiently inhibit the growth of tumors and reduce susceptibility to cancer. None of these studies, however, reported a consistent outcome with regard to the mechanisms underlying the anticancer effects of lactoferrin. In this review, the association of lactoferrin with cancer is thoroughly discussed, from lactoferrin gene expression to the potential use of lactoferrin in cancer therapy. Lactoferrin cytotoxicity against several cancers is reported to occur in distinct ways under different conditions, namely by cell membrane disruption, apoptosis induction, cell cycle arrest, and cell immunoreaction. Based on these mechanisms, new strategies to improve the anticancer effects of the lactoferrin protein and/or its derivatives are proposed. The potential for lactoferrin in the field of cancer research (including as a chemotherapeutic agent in cancer therapy) is also discussed.

Bovine lactoferrin induces cell cycle arrest and inhibits mTOR signaling in breast cancer cells

Lactoferrin (LF) is predominantly found in mammalian secretions with recognized anticancer potential, although the mechanisms involved in such activity are still unclear. Here, the stability, internalization, and cytotoxicity of bovine LF (bLF) and its variants were tested against a panel of breast cancer cells. bLF was found to be very stable under incubation with cells and also able to internalize them, although most of the protein remained in the culture medium. Furthermore, bLF (up to 30 μM) inhibited the growth of breast cancer cells (T-47D, MDA-MB-231, Hs578T, and MCF-7) in a higher extent than in the normal counterpart cell line (MCF-10-2A), thus suggesting its selectivity. Regarding its variants, only the iron-saturated protein showed a higher activity compared with the commercial bLF. bLF growth inhibitory activity was associated with the induction of cell cycle arrest, but not with apoptosis. Moreover, exposure to bLF increased the cells phospho-AMPKα levels and decreased both phospho threonine mammalian target of rapamycin (mTOR) and total mTOR levels, indicating a novel mechanism of action through its ability to induce nutrient/energy-related stress. This study disclosed important findings to better understand the mechanisms underlying the bLF effects on breast cancer cell lines, which could be valuable for novel advances in the cancer research field.

Bovine lactoferrin ingestion protects against inflammation via IL-11 induction in the small intestine of mice with hepatitis

Accumulating evidence suggests that orally ingested lactoferrin protects against inflammation. To assess the efficacy of orally administered bovine lactoferrin (bLF) against hepatitis and to identify the underlying mechanism, in the present study, we used four mouse models of hepatitis induced by d-galactosamine (GalN), carbon tetrachloride (CCl4), GalN plus lipopolysaccharide (LPS) and zymosan plus LPS. Intraperitoneal (i.p.) injection of GalN (500 mg/kg body weight) in mice treated with bovine serum albumin (BSA) for 14 d significantly increased serum aspartate aminotransferase (AST) concentrations compared with the untreated mice. However, orally administered bLF reduced AST concentrations compared with BSA treatment. In mice that received a single injection (0·4 ml/kg) and twice-weekly injections (0·08 ml/kg) of CCl4 for 24 weeks and pretreated with bLF for 14 d and 24 weeks, respectively, significantly suppressed alanine aminotransferase and AST concentrations were observed compared with the BSA-treated control. Oral administration of bLF for 14 d before i.p. injection of LPS (5 mg/kg) plus GalN (1 g/kg) significantly improved the survival rate. In mice that received intravenous injection of zymosan (25 mg/kg) and LPS (15 μg/kg) at 7 d intervals, bLF reduced the elevation of AST concentrations and enhanced the production of IL-11 and bone morphogenetic protein 2 in the small intestine compared with the BSA-treated control. To evaluate the effects of IL-11, we used IL-11 receptor α-null mice treated with GalN, CCl4 and zymosan plus LPS. In this group, the activity of bLF was not significantly different from that of BSA. These data indicate that orally ingested bLF enhances the expression of IL-11 in the small intestine and up-regulates protective activity in mice with hepatitis.

Inhibitory effects of human lactoferrin on U14 cervical carcinoma through upregulation of the immune response

Human lactoferrin (hLF) is a multifunctional glycoprotein that inhibits cancer growth. However, the inhibitory effect of this glycoprotein in cervical cancer remains inconclusive. This study investigated the efficacy of hLF on the inhibition of U14 cervical cancer in vivo. Recombinant adenovirus carrying hLF (Ad-hLF) were constructed. Mice inoculated with U14 cells were randomly allocated to four treatments: i) Phosphate-buffered saline (negative control), ii) Ad-green fluorescent protein (negative control), iii) Ad-hLF (studied) or iv) cyclophosphamide (CTX; positive control). Tumor growth, as well as levels of natural killer (NK) cells, CD4⁺ and CD8⁺ peripheral blood T lymphocyte subpopulations, serum cytokines and vascular endothelial growth factor (VEGF) in tumor tissues were detected. Compared with the negative controls, tumor growth was inhibited by hLF and mice lifespans in the Ad-hLF-treated group were prolonged to reach the levels of the CTX-treated group. The activity of tumor-killing NK cells was upregulated by hLF. Moreover, the number of CD4⁺ and CD8⁺ peripheral blood T lymphocyte subpopulations increased following treatment with Ad-hLF. Treatment with Ad-hLF increased the levels of serum interferon-γ, serum interleukin-2 (IL-2) and tumor necrosis factor-α, and decreased the levels of serum IL-4 in tumor-bearing mice. The expression of VEGF in tumor tissues was downregulated by hLF. In conclusion, hLF inhibits the growth of U14 solid tumors by modulating the immune response of tumor-bearing mice.

Oral administration of lactoferrin attenuates intestinal ischemia-reperfusion injury in rats

BACKGROUND

Intestinal ischemia-reperfusion (I/R) is a common and serious clinical condition. Lactoferrin (Lf) has displayed antioxidative and anti-inflammatory activities in protecting the intestinal mucosa. The objective of this study was to investigate whether oral administration of Lf could attenuate I/R-induced intestinal injury.

METHODS

The experimental design consisted of three groups of Wistar rats (24 per group): sham operation, control (I/R, saline), Lf (I/R, Lf). Intestinal I/R was produced by occlusion of the superior mesenteric artery for 45 min. Eight rats from each group were randomly sacrificed 3, 12 or 36 h after reperfusion, and blood and intestinal samples were collected.

RESULTS

Intestinal I/R resulted in gut damage evidenced by morphological alteration, reduction of γ-glutamyl transpeptidase (γ-GGT) activity and increased cell apoptosis. Daily administration of Lf (200 mg/kg) for 14 days before surgery significantly attenuated gut damage by reducing the histologic score and apoptosis index, and restoring intestinal γ-GGT activity. Lf reduced intestinal malondialdehyde and myeloperoxidase, restored glutathione and decreased serum levels of tumor necrosis factor-α, interleukin (IL)-1β and IL-6 compared with saline control in I/R rats. In addition, oral administration of Lf did not produce any significant effects in healthy rats; Lf at doses of 50 or 100 mg/kg also attenuated I/R-induced gut damage, but administration of Lf for 7 days did not exert a significant protective effect against I/R-induced gut damage.

CONCLUSIONS

These results indicate that Lf may serve as a potent supplement in protecting the gut from intestinal I/R-induced injury by its antioxidative, anti-inflammatory and antiapoptotic activities.

Intestinal receptor targeting for peptide delivery: an expert's personal perspective on reasons for failure and new opportunities

The technology has been available more than 25 years that would enable the oral delivery of vaccines, proteins and peptides, thus avoiding the need for injection. To this day, injection is still the mode of delivery, yet not the main mode of choice. This review focuses on several of the potential modes for oral delivery of peptides, proteins and vaccines. Additionally, the review will provide the reader with an insight into the problems and potential solutions for several of these modes of oral delivery of peptides and proteins.

Growth suppression effects of recombinant adenovirus expressing human lactoferrin on cervical cancer in vitro and in vivo

Human lactoferrin (hLF) is a multifunctional glycoprotein that can inhibit cancer growth. The molecular mechanism of hLF-induced tumor growth inhibition is incompletely understood. Moreover, the adenovirus vector-mediated hLF (Ad-hLF) gene therapy on cervical cancer has not been yet characterized. In this study, the replication-deficient Ad-hLF was used to explore tumor growth suppression effects on cervical cancer in vitro and in vivo. The results showed that the recombinant adenovirus encoding hLF delivery resulted in a more differential tumor growth inhibition, and this growth arrest was caused by cell cycle inhibition at G2/M phase. In addition, Fas, a death-inducing receptor, and Bax, a member of pro-apoptotic Bcl-2 family, were increased in the sample of cervical cancer tissue treated by Ad-hLF. Further, it was also observed that caspase-3 was activated and the expression of anti-apoptotic Bcl-2 was decreased. These results indicated that the growth inhibitory effects of Ad-hLF on cervical cancer were caused by elevated expression of Fas and decreased the ratio of anti- to pro-apoptotic molecule Bcl-2/Bax.

Lactoferrin and cancer disease prevention

Lactoferrin (LF) is an iron-binding glycoprotein that is composed of the transferrin family and is predominantly found in the products of the exocrine glands located in the gateways of the digestive, respiratory, and reproductive systems, suggesting a role in the non-specific defence against invading pathogens. Additionally, several physiological roles have been attributed to LF, namely regulation of iron homeostasis, host defence against infection and inflammation, regulation of cellular growth, and differentiation and protection against cancer development and metastasis. These findings have suggested LF's great potential therapeutic use in cancer disease prevention and/or treatment, namely as a chemopreventive agent. This review looks at the recent advances in understanding the mechanisms underlying the multifunctional roles of LF and future perspectives on its potential therapeutic applications.

Emerging health properties of whey proteins and their clinical implications

The nursery rhyme "Little Miss Muffet sat on a tuffet (small stool) eating her curds and whey. ..." is recognition of the fact that over the centuries "curds and whey", the two major components of cow's milk, have been widely accepted as part of a healthy diet. Milk provides complete nourishment for the neonate for six months from birth, containing factors that help develop various organ systems including the brain, immune system, and the intestine. Importantly it provides immune protection at a time when the neonates own immune system, though fully developed, is albeit immature. Many adult consumers include cow's milk as part of a healthy diet as it provides protein and essential nutrients, vitamins, and minerals, in particular calcium for strong bones. There is a growing appreciation that milk, and in particular whey, contains components that not only provide nutrition, but can also prevent and attenuate disease, or augment conventional therapies, when delivered in amounts that exceed normal dietary intakes. This paper reviews the emerging health properties of whey proteins and their clinical implications.

Prevention of carcinogenesis and cancer metastasis by bovine lactoferrin

Increasing attention is being paid to chemopreventive agents for individuals at high risk of cancer. We have concentrated on bovine lactoferrin (bLF), an 80 kDa iron-binding glycoprotein known to have anti-microbial and immunoprotective effects. Lactoferrin is particularly abundant in colostrum, and is also present in tears, saliva and seminal and uterine secretions. However, only little is known regarding its influence on carcinogenesis. We have shown preventive effects of bLF and its fragment peptide, lactoferricin (bLFcin), consisting of a 25 amino acid sequence without iron binding capacity, on chemically-induced colon carcinogenesis in the rat and transplanted carcinoma cell metastasis in the mouse. The mechanisms are wide-spectrum, including elevation of caspase-1 and IL-18 in the small intestine, enhancement of the cell killing activity of cytotoxic T and natural killer (NK) cells, and anti-inflammatory and anti-angiogenic effects. It also inhibits the induction of liver CYP1A2, a carcinogen activating enzyme, and induces apoptosis in the colon epithelium of carcinogen treated rats. Thus, bLF possesses multi-functional potential to suppress carcinogenesis and is a good candidate for practical application in humans.

Post-initiation chemopreventive effects of dietary bovine lactoferrin on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumorigenesis in female A/J mice

We investigated the effects of bovine LF (bLF) on different phases of NNK-induced lung tumorigenesis in A/J mice. Mice were orally administered 0.02, 0.2 and 2% bLF during the initiation phase, and 2% bLF during the whole tumorigenesis phase or post-initiation phase. Administered bLF during the post-initiation phase showed significant reduction of macroscopical lung nodules, and immunohistochemically decreased expression levels of cell proliferation marker and increased expression levels of apoptosis marker in lung proliferative lesions. bLF might inhibit NNK-induced mouse lung tumorigenesis, only when given limited to the post-initiation phase, through modification of cell proliferation and/or apoptosis.

Novel antimutagenic factors derived from the edible mushroom Agrocybe cylindracea

Studies have shown that certain foods contain compounds with antigenotoxic activities. Here, we ask if dried powders and/or extracts from three edible mushrooms, Agrocybe cylindracea, Lentinula edodes and Pleurotus ostreatus, have a mitigating effect on genotoxicity. We used two in vivo assays: the Drosophila DNA repair test and the Drosophila wing spot test (also known as SMART) which measures somatic mutation and recombination. Eight carcinogens were tested with the mushroom powders: 2-AAF, aflatoxin B1, DMBA, IQ, MeIQx, MNU NDMA, and 4NQO. We found that A. cylindracea and P. ostreatus powders can suppress DNA damage induced by each of the mutagens we tested. In contrast, L. edodes has an inhibitory effect on DNA damage induced by only a sub-set of mutagens, namely aflatoxin B1, NDMA, MNU and 4NQO. In addition, A. cylindracea extracts were able to suppress somatic cell mutation induced by aflatoxin B1, MMC, MNU, NDMA, NMOR and 4NQO. These results suggest that Agrocybe genus mushrooms contain factors with antigenotoxic activity, including anti-recombinogenic activity. Furthermore, the antigenotoxic activity of A. cylindracea powder can be extracted in water but not in ethyl acetate or methanol, and is sensitive to heat treatment. The data suggest that there is a novel antigenotoxic factor(s) in A. cylindracea, possibly in the form of a peptide or protein.

Gene expression alterations in the non-neoplastic parenchyma adjacent to infiltrating pancreatic ductal adenocarcinoma

The non-neoplastic pancreatic parenchyma adjacent to infiltrating ductal adenocarcinoma demonstrates inflammation, fibrosis, acinar cell loss and small duct-like metaplasia of acinar cells. Similar morphologic changes are also observed in the setting of chronic pancreatitis. In addition, peritumoral acini have been shown to have alterations in gene expression even in the absence of morphological changes. To better understand the pancreatic acinar responses to infiltrating pancreatic ductal adenocarcinoma, we characterized gene expression patterns of pancreatic acinar tissue adjacent to infiltrating pancreatic ductal adenocarcinomas and compared them to gene expression patterns of acinar tissue affected by chronic pancreatitis as well as to those of normal pancreatic acini. Fresh-frozen pancreatic acinar tissue was microdissected from nine patients (three with pancreatic cancer, three with chronic pancreatitis, three with normal pancreata) using laser capture microdissection, and extracted RNA from each microdissection was subjected to two rounds of linear amplification and hybridized to oligonucleotide microarrays. Gene expression patterns were confirmed using quantitative RT-PCR and/or immunohistochemistry. A total of 20 genes was found to be overexpressed in peritumoral acinar tissue compared to normal acinar tissue and to acini affected by chronic pancreatitis. These 20 genes included pancreatitis-associated protein (HIP/PAP), a gene known to be overexpressed in acini adjacent to infiltrating pancreatic cancer, and the gene cartilage glycoprotein-39 (HC gp-39 or TKL-40). Serum HC gp-39 protein levels were significantly higher in patients with pancreatic cancer and in those with chronic pancreatitis than in controls without pancreatic disease. There was no significant difference in the levels of serum HC gp-39 in patients with pancreatic cancer and those with chronic pancreatitis. Our results demonstrate some of the molecular alterations in acinar cells that occur in response to adjacent infiltrating pancreatic ductal adenocarcinoma and reveal that such alterations can provide a rich source of markers of pancreatic cancer.

Pepsin-Digested Bovine Lactoferrin Induces Apoptotic Cell Death With JNK/SAPK Activation in Oral Cancer Cells

Lactoferrin, a member of the transferrin family, is iron-binding and a strongly cationic 76 kDa glycoprotein. In breast milk it is secreted in high concentrations from glandular epithelia and is also present in other exocrine fluids including saliva. In the present study, we examined the biological mechanisms of apoptosis induced by pepsin-digested-lactoferrin peptide (Lfn-p) in the human oral squamous cell carcinoma cell line SAS. We found that treatment with Lfn-p induced cell death with apoptotic nuclear changes, preceded by the cleavage of caspase-3 and poly (ADP-ribose) polymerase (PARP) in the apoptotic cells. Treatment with Lfn-p induced phosphorylation of extracellular signal-regulated kinase (ERK1/2), a member of the MAP kinase family, at early stages of apoptosis. Another MAP kinase, c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK), was also phosphorylated by treatment with Lfn-p. Pretreatment of SAS cells with SP600125, a JNK/SAPK inhibitor, diminished Lfn-induced apoptosis, as assessed by determining released lactate dehydrogenase activity. On the other hand, the MEK1 inhibitors PD98059 or U0126 showed no effect on repression of cell death, but rather an increase. These results suggest that JNK/SAPK activation may play an important role in Lfn-p-induced apoptotic cell death of human oral squamous cell carcinoma cells.

Human Apo-Lactoferrin Enhances Angiogenesis Mediated by Vascular Endothelial Growth Factor A in vivo

BACKGROUND

Lactoferrin, LF, a multifunctional iron- and heparin-binding protein, present in exocrine body secretions and leukocytes, is remarkably resistant to proteolysis. Ingested bovine iron-unsaturated LF, apo-bLF, suppresses VEGF-A-mediated angiogenesis in a previously described rat mesentery angiogenesis assay, possibly explaining, at least in part, its established anticancer effect in rats and mice.

METHODS

Using the same experimental system, we have now studied the effect of (i) ingested human apo-LF, apo-hLF, on angiogenesis mediated by VEGF-A and bFGF, (ii) ingested human iron-saturated LF, holo-hLF, on VEGF-A-mediated angiogenesis and (iii) subcutaneous continuously infused apo-hLF on VEGF-A-mediated angiogenesis.

RESULTS

Ingested holo-hLF did not affect VEGF-A-mediated angiogenesis. Ingested apo-hLF (from one and the same batch) significantly enhanced VEGF-A-mediated angiogenesis but did not affect bFGF-mediated angiogenesis. Moreover, subcutaneously infused apo-hLF also significantly stimulated VEGF-A-mediated angiogenesis.

CONCLUSION

Taken together, the data suggest that apo-hLF exerts a specific proangiogenic effect in VEGF-A-mediated angiogenesis. Clearly, human and bovine apo-LF exert opposite effects on VEGF-A-induced angiogenesis. Differences in molecular features between human and bovine LFs of possible significance for the outcome are discussed. In hypoxia, compensatory collateral circulation is mediated primarily by VEGF-A. We hypothesize that systemically administered apo-hLF may promote collateral blood vessel formation at hypoxic sites in normal tissue, thus counteracting ischemia and infarction.

Lactoferrin modifies apoptosis-related gene expression in the colon of the azoxymethane-treated rat

Lactoferrin, an iron-binding glycoprotein, exhibits suppressive effects on development of azoxymethane (AOM)-induced tumors in the rat colon, but the mechanisms are largely unknown. In this study, we investigated the effect of lactoferrin on the gene expression of 10 apoptosis-related molecules in colon mucosa of AOM-treated rats during early and late stages of colon carcinogenesis by reverse transcription PCR. Here we document that a death-inducing receptor, Fas, and a pro-apoptotic Bcl-2 family member, Bid, are increased in the colon mucosa in proportion to decreases in AOM-induced aberrant crypt foci by lactoferrin. Similarly, increased expression of the pro-apoptotic Bcl-2 family member, Bax, was also observed in AOM-induced tumors in rats fed by lactoferrin. These results indicate that Fas and pro-apoptotic Bcl-2 members participate in the lactoferrin action and may contribute to suppressive effects on tumor development in the rat colon.

Oral lactoferrin inhibits growth of established tumors and potentiates conventional chemotherapy

In this work, we investigated the anticancer activity of orally administered recombinant human lactoferrin (rhLF) alone and in combination with chemotherapy in tumor-bearing mice. rhLF inhibited the growth of squamous cell carcinoma (O12) tumors in T cell-immunocompromised nu/nu mice by 80% when administered at 1,000 mg/kg (2.9 g/m2) by oral gavage twice daily for 8 days (p < 0.001). Similar activity was observed in syngeneic, immunocompetent BALB/c mice, where orally administered rhLF (1,000 mg/kg, 2.9 g/m2 once daily) halted the growth of mammary adenocarcinoma TUBO. Oral rhLF (200 mg/kg, 0.57 g/m2) was also used alone and in combination with cis-platinum (5 mg/kg) to treat head-and-neck squamous cell carcinoma in a syngeneic murine model. Monotherapy with oral rhLF or cis-platinum caused 61% or 66% tumor growth inhibition over placebo, respectively. Mice receiving both therapies showed 79% growth inhibition, a statistically significant improvement over each drug alone. We then demonstrated that administration of oral rhLF (300 mg/kg, 0.86 g/m2) to tumor-bearing or naive mice resulted in (i) significantly increased production of IL-18 in the intestinal tract, (ii) systemic NK cell activation and (iii) circulating CD8+ T-cell expansion. These data suggest that oral rhLF is an immunomodulatory agent active against cancer as a single agent and in combination chemotherapy, exerting its systemic effect through stimulation of IL-18 and other cytokines in the gut enterocytes. rhLF has been administered orally to 211 people without a single serious drug-related adverse event. Thus, rhLF shows promise as a safe and well-tolerated novel immunomodulatory anticancer agent.

Lactoferrin reduces methotrexate-induced small intestinal damage, possibly through inhibition of GLP-2-mediated epithelial cell proliferation

A strategy protecting the small intestine against deleterious side effects associated with anti-cancer therapy is arresting epithelial cell cycling temporally. Since endogenous glucagon-like peptide-2 (GLP-2) is a trophic factor specific for intestinal epithelia, the possibility of inhibiting GLP-2-mediated cell proliferation by lactoferrin, thereby protecting the small intestine against deleterious side effects of anticancer therapy, was investigated. In Caco-2 cells, GLP-2-mediated proliferation was reduced in a dose-dependent manner using lactoferrin. Furthermore, in a rat model for methotrexate-induced mucositis, lactoferrin reduced BrdU incorporation in small intestinal epithelial cells, indicating inhibition of epithelial cell proliferation in vivo. Subsequently, protection against methotrexate-induced intestinal damage was found in corresponding regions. These results show, for the first time, that lactoferrin interferes with GLP-2-induced intestinal epithelial proliferation. It may therefore be hypothesized that lactoferrin protects the intestine against anticancer therapy-induced intestinal damage, via inhibition of GLP-2-induced small intestinal epithelial cell proliferation.

Search for unknown tumor-antagonizing genes

Following the ingenious prediction of Alfred Knudson in 1971, the first tumor suppressor gene, RB1, has been isolated. Its product, the RB1 protein, was found to play a major role in the control of the cell cycle. The loss of heterozygosity (LOH) technique, introduced by Cavenee and colleagues, was an important milestone toward the confirmation of Knudson's hypothesis and the identification of the gene. Subsequently, the LOH technique has provided important clues that have led to the discovery of other tumor suppressor genes. Most of them play important roles in the regulation of the cell cycle and/or of apoptosis. Circumstantial evidence suggests that still other and perhaps many unknown genes may participate in the protection of the organism against malignant growth. The numerous genome losses in tumors, detected by LOH, comparative genomic hybridization, and by cytogenetic techniques, support this possibility. The early work of one of us (G.K.), together with Henry Harris and Francis Wiener, had shown that the malignant phenotype can be suppressed by hybridizing malignant with low- or non-tumorigenic cells. However, analysis of this phenomenon failed to assign the inhibition of tumorigenicity to any particular gene. We have pursued the search for new tumor-antagonizing genes with two unconventional approaches, focusing on human chromosomal subband 3p21.3, a region frequently targeted by cytogenetically detectable deletions. We have detected four clusters of candidate tumor suppressor genes at 3p21.3 by a combination of deletion mapping and the "elimination test." These findings raise the question whether the number and variety of genes that may contribute to the defense against uncontrolled proliferation may have been underestimated.

Effects of lactoferrin, soya germ and polyamine on 2-amino-1-methyl-6- phenylimidazo[4,5-b]-pyridine(PhIP)- induced breast carcinogenesis in rats

The cancer-preventive effects of food-derived bovine lactoferrin(bLF), isoflavone-rich soya germ(SG), and spermidine(SPD) on mammary gland carcinogenesis induced by 2-amino-1- methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP), were investigated in female Sprague-Dawley(SD) rats. Two hundred and six female SD rats were divided into 8 groups. Cumulative breast cancer incidence at 43 weeks was 65.4% in the PhIP group; 80.0% and 76.0% in the 0.2% and 2.0% bLF groups, respectively; 58.3% and 20.0% in the 2% and 10% SG groups, respectively; and 80.0% and 76.9% in the 0.035% and 0.175% SPD groups, respectively. Isoflavone-rich SG significantly suppressed breast cancer, and the tumors showed fibrous or less malignant features upon histological examination.

Dietary bovine lactoferrin induces changes in immunity level and disease resistance in Asian catfish Clarias batrachus

The effects of including bovine lactoferrin (Lf) in the diet of the Asian catfish (Clarias batrachus) on specific and non-specific immunity as well as disease resistance were investigated. The catfish were fed four different diets for 2 weeks: a commercial diet as control and the same diet supplemented with 50, 100 and 200mg bovine Lf/kg feed. After 1 and 2 weeks, serum bacterial agglutination titre against Aeromonas hydrophila as a measure of specific immunity; natural serum haemolysin titre, lysozyme activity and oxidative radical production by neutrophils as a measure of non-specific immunity as well as disease resistance against A. hydrophila challenge to vaccinated and non-vaccinated animals were evaluated. The results showed that Lf supplements, particularly at 100mg level, significantly (P<0.05) enhanced serum lysozyme level, oxidative radical production and level of protection against A. hydrophila challenge in non-vaccinated animals irrespective of length of exposure. The specific immunity was not influenced by Lf feeding as evidenced from the bacterial agglutination titre and level of protection in vaccinated animals. As Lf feeding at 100mg/kg for 1 week is able to enhance the non-specific immunity and disease resistance of catfish efficiently, these results support the possible use of Lf as an immunostimulant for farmed catfish.

Consistent downregulation of human lactoferrin gene, in the common eliminated region 1 on 3p21.3, following tumor growth in severe combined immunodeficient (SCID) mice

Lactoferrin (LF) is one of 19 active genes in the common eliminated region 1 at 3p21.3 identified by us. LF was transfected into mouse fibrosarcoma A9. Fourteen severe combined immunodeficient (SCID) derived tumors from two PI based artificial chromosome (PAC)-transfectants containing the entire LF gene and two LF-cDNA transfectants were analyzed by real time polymerase chain reaction at the DNA and RNA level. Following SCID tumor passage, LF expression was decreased or eclipsed, in all tumors although DNA levels did not change considerably. Promoter methylation and/or rearrangement of the insertion site may be responsible for human LF downregulation in mouse fibrosarcoma derived tumors.

Cancer prevention by bovine lactoferrin and underlying mechanisms--a review of experimental and clinical studies

In experimental studies, bovine lactoferrin (bLF) has been found to significantly inhibit colon, esophagus, lung, and bladder carcinogenesis in rats when administered orally in the post-initiation stage. Furthermore, concomitant administration with carcinogens resulted in inhibition of colon carcinogenesis, possibly by suppression of phase I enzymes, such as cytochrome P450 1A2 (CYP1A2), which is preferentially induced by carcinogenic heterocyclic amines. Enhancement of the activities of their phase II counterparts, such as glutathione S-transferase might have also played a critical role in post-initiation suppression in a study of tongue carcinogenesis. Anti-metastatic effects were moreover detected when bLF was given intragastrically to mice bearing highly metastatic colon carcinoma 26 cells (Co 26Lu), with apparent enhancing influence on local and systemic immunity. Marked increase in the number of cytotoxic T and NK cells in the mucosal layer of the small intestine and peripheral blood cells was thus found, this in turn enhancing the production of Interleukin 18 (IL-18) and caspase-1 in the epithelial cells of the small intestine, with possible consequent induction of interferon (IFN)-gamma positive cells. Furthermore, bLF has been found to exert anti-hepatitis C virus (HCV) activity in a preliminary clinical trial in patients with chronic active hepatitis due to this virus, a main causative factor in hepatocellular carcinoma development in Japanese. More extensive clinical trials are now underway in the National Cancer Center Hospital and other institutes to further explore the preventive potential against colon carcinogenesis.

Bovine lactoferrin and lactoferricin derived from milk: production and applications

Bovine lactoferrin is produced on an industrial scale from cheese whey or skim milk. The safety of purified lactoferrin has been confirmed from the results of a reverse mutation test using bacteria, a 13-week oral repeated-dose toxicity study in rats, and clinical studies. In order to apply active lactoferrin to various products, a process for its pasteurization was developed. Subsequently, lactoferrin has been used in a wide variety of products since it was first added to infant formula in 1986. A pepsin hydrolysate of lactoferrin is also used in infant formula. This hydrolysate contains a potent antimicrobial peptide named lactoferricin that is derived from the lactoferrin molecule by pepsin digestion. Semilarge-scale purification of lactoferricin can be performed by hydrophobic interaction chromatography. Lactoferricin also exhibits several biological actions and appears to be the functional domain of lactoferrin. Recent studies have demonstrated that oral administration of lactoferrin or lactoferricin exerts a host-protective effect in various animals and in humans. The results of these studies strongly suggest that the effects of oral lactoferrin are mediated by modulation of the immune system. Further elucidation of the clinical efficacy and mechanism of action of lactoferrin will increase the value of lactoferrin-containing products.

Down-regulation of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx)-induced CYP1A2 expression is associated with bovine lactoferrin inhibition of MeIQx-induced liver and colon carcinogenesis in rats

The inhibitory influence of bovine lactoferrin (bLF) on induction of preneoplastic hepatic glutathione S-transferase placental form-positive (GST-P( +)) cell foci and colon aberrant crypt foci (ACF) by diethylnitrosamine (DEN) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) was investigated in F344 rats. Rats were initially treated with DEN, then placed on basal diet containing MeIQx (200 ppm) alone, MeIQx plus 2% bLF, or MeIQx plus 0.2% bLF from week 2 to week 8, with partial hepatectomy performed at week 3. Concomitant administration of 2% or 0.2% bLF with MeIQx caused significant dose-dependent decreases in both number and unit area of GST-P(+) cell foci (2% bLF, P < 0.001; 0.2% bLF, P < 0.01). Similar results were observed for MeIQx-induced colon ACF in the groups without DEN treatment (2% and 0.2% bLF, P < 0.05). To investigate the underlying mechanisms, we analyzed the influence of bLF on levels of cytochrome P4501A2 (CYP1A2), a metabolically activating enzyme of MeIQx in the liver. The results demonstrated that combined administration of 2% bLF significantly reduced levels of MeIQx-induced CYP1A2 mRNA (P < 0.05) and protein (P < 0.05) to the normal levels, in association with reduced values for MeIQx-DNA adducts (P < 0.05), liver GST-P(+) cell foci and colon ACF. These results suggest that bLF is a chemopreventive agent for DEN alone or DEN plus MeIQx-induced liver, and MeIQx-induced colon carcinogenesis in rats. One possible mechanism is a normalizing down-regulation of CYP1A2 expression by bLF, with consequent reduction of carcinogen activation and adduct formation.