Regulation of the colon-targeted release rate of lactoferrin by constructing hydrophobic ethyl cellulose/pectin composite nanofibrous carrier and its effect on anti-colon cancer activity

In order to modify colonic release behavior of lactoferrin (Lf), a hydrophobic composite nanofibrous carrier (CNC) was constructed by emulsion coaxial electrospinning. Ethylcellulose/pectin based water-in-oil emulsion and Lf-contained polyvinyl alcohol solution were used as shell and core fluids, respectively. An electrospinning diagram was first constructed to screen out suitable viscosity (51-82 cP) and conductivity (960-1300 μS/cm) of the dispersed phase of pectin solution for successful electrospinning of shell emulsion. Varying mass fraction of pectin solution (5 %-20 %) of shell emulsion during emulsion coaxial electrospinning obtained CNCs with different micro-structures, labeled as 5&95 CNC, 10&90 CNC, 15&85 CNC, 20&80 CNC. These CNCs all achieved colonic delivery of Lf (>95 %), and the time for complete release of Lf in simulated colon fermentation process were 10, 7, 5 and 3 h, respectively. That is, the greater the pectin content in CNC, the faster the release rate of stabilized Lf in colon. Lf release in simulated colon fermentation fluid involved complex mechanisms, in which diffusion release of Lf was dominant. Increasing colonic release rate of Lf enhanced its regulation effect on the expression levels of cell cycle arrest and apoptosis-related protein and promote its effective inhibition on the proliferation of HCT116 cell.

Application Value of Antimicrobial Peptides in Gastrointestinal Tumors

Gastrointestinal cancer is a common clinical malignant tumor disease that seriously endangers human health and lacks effective treatment methods. As part of the innate immune defense of many organisms, antimicrobial peptides not only have broad-spectrum antibacterial activity but also can specifically kill tumor cells. The positive charge of antimicrobial peptides under neutral conditions determines their high selectivity to tumor cells. In addition, antimicrobial peptides also have unique anticancer mechanisms, such as inducing apoptosis, autophagy, cell cycle arrest, membrane destruction, and inhibition of metastasis, which highlights the low drug resistance and high specificity of antimicrobial peptides. In this review, we summarize the related studies on antimicrobial peptides in the treatment of digestive tract tumors, mainly oral cancer, esophageal cancer, gastric cancer, liver cancer, pancreatic cancer, and colorectal cancer. This paper describes the therapeutic advantages of antimicrobial peptides due to their unique anticancer mechanisms. The length, net charge, and secondary structure of antimicrobial peptides can be modified by design or modification to further enhance their anticancer effects. In summary, as an emerging cancer treatment drug, antimicrobial peptides need to be further studied to realize their application in gastrointestinal cancer diseases.

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 as a Human Genome “Guardian”—An Overall Point of View

Structural abnormalities causing DNA modifications of the ethene and propanoadducts can lead to mutations and permanent damage to human genetic material. Such changes may cause premature aging and cell degeneration and death as well as severe impairment of tissue and organ function. This may lead to the development of various diseases, including cancer. In response to a damage, cells have developed defense mechanisms aimed at preventing disease and repairing damaged genetic material or diverting it into apoptosis. All of the mechanisms described above are part of the repertoire of action of Lactoferrin—an endogenous protein that contains iron in its structure, which gives it numerous antibacterial, antiviral, antifungal and anticancer properties. The aim of the article is to synthetically present the new and innovative role of lactoferrin in the protection of human genetic material against internal and external damage, described by the modulation mechanisms of the cell cycle at all its levels and the mechanisms of its repair.

Impact of food-derived bioactive peptides on gut function and health

The gastrointestinal tract (GIT) is the largest interface between our body and the environment. It is an organ system extending from the mouth to the anus and functions for food intake, digestion, transport and absorption of nutrients, meanwhile providing protection from environmental factors, like toxins, antigens, and pathogens. Diet is one of the leading factors modulating the function of the GIT. Bioactive peptides presenting naturally in food or derived from food proteins during digestion or processing have been revealed multifunctional in diverse biological processes, including maintaining gut health and function. This review summarizes the available evidence regarding the effects of food-derived bioactive peptides on gut function and health. Findings and insights from studies based on in vitro and animal models are discussed. The gastrointestinal mucosa maintains a delicate balance between immune tolerance to nutrients and harmful components, which is crucial for the digestive system's normal functions. Dietary bioactive peptides positively impact gastrointestinal homeostasis by modulating the barrier function, immune responses, and gut microbiota. However, there is limited clinical evidence on the safety and efficacy of bioactive peptides, much less on the applications of dietary peptides for the treatment or prevention of diseases related to the GIT. Further study is warranted to establish the applications of bioactive peptides in regulating gut health and function.

Lactoferrin and Its Derived Peptides: An Alternative for Combating Virulence Mechanisms Developed by Pathogens

Due to the emergence of multidrug-resistant pathogens, it is necessary to develop options to fight infections caused by these agents. Lactoferrin (Lf) is a cationic nonheme multifunctional glycoprotein of the innate immune system of mammals that provides numerous benefits. Lf is bacteriostatic and/or bactericidal, can stimulate cell proliferation and differentiation, facilitate iron absorption, improve neural development and cognition, promote bone growth, prevent cancer and exert anti-inflammatory and immunoregulatory effects. Lactoferrin is present in colostrum and milk and is also produced by the secondary granules of polymorphonuclear leukocytes, which store this glycoprotein and release it at sites of infection. Lf is also present in many fluids and exocrine secretions, on the surfaces of the digestive, respiratory and reproductive systems that are commonly exposed to pathogens. Apo-Lf (an iron-free molecule) can be microbiostatic due to its ability to capture ferric iron, blocking the availability of host iron to pathogens. However, apo-Lf is mostly microbicidal via its interaction with the microbial surface, causing membrane damage and altering its permeability function. Lf can inhibit viral entry by binding to cell receptors or viral particles. Lf is also able to counter different important mechanisms evolved by microbial pathogens to infect and invade the host, such as adherence, colonization, invasion, production of biofilms and production of virulence factors such as proteases and toxins. Lf can also cause mitochondrial and caspase-dependent regulated cell death and apoptosis-like in pathogenic yeasts. All of these mechanisms are important targets for treatment with Lf. Holo-Lf (the iron-saturated molecule) can contain up to two ferric ions and can also be microbicidal against some pathogens. On the other hand, lactoferricins (Lfcins) are peptides derived from the N-terminus of Lf that are produced by proteolysis with pepsin under acidic conditions, and they cause similar effects on pathogens to those caused by the parental Lf. Synthetic analog peptides comprising the N-terminus Lf region similarly exhibit potent antimicrobial properties. Importantly, there are no reported pathogens that are resistant to Lf and Lfcins; in addition, Lf and Lfcins have shown a synergistic effect with antimicrobial and antiviral drugs. Due to the Lf properties being microbiostatic, microbicidal, anti-inflammatory and an immune modulator, it represents an excellent natural alternative either alone or as adjuvant in the combat to antibiotic multidrug-resistant bacteria and other pathogens. This review aimed to evaluate the data that appeared in the literature about the effects of Lf and its derived peptides on pathogenic bacteria, protozoa, fungi and viruses and how Lf and Lfcins inhibit the mechanisms developed by these pathogens to cause disease.

Gastrointestinal Digestion of Food Proteins under the Effects of Released Bioactive Peptides on Digestive Health

The gastrointestinal tract represents a specialized interface between the organism and the external environment. Because of its direct contact with lumen substances, the modulation of digestive functions by dietary substances is supported by a growing body of evidence. Food-derived bioactive peptides have demonstrated a plethora of activities in the organism with increasing interest toward their impact over the digestive system and related physiological effects. This review updates the biological effects of food proteins, specifically milk and soybean proteins, associated to gastrointestinal health and highlights the study of digestion products and released peptides, the identification of the active form/s, and the evaluation of the mechanisms of action underlying their relationship with the digestive cells and receptors. The approach toward the modifications that food proteins and peptides undergo during gastrointestinal digestion and their bioavailability is a crucial step for current investigations on the field. The recent literature on the regulation of digestive functions by peptides has been mostly considered in terms of their influence on gastrointestinal motility and signaling, oxidative damage and inflammation, and malignant cellular proliferation. A final section regarding the actual challenges and future perspectives in this scientific topic is critically discussed.

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.

Selective cytotoxic effect against the MDA-MB-468 breast cancer cell line of the antibacterial palindromic peptide derived from bovine lactoferricin

The cytotoxic effect against the breast cancer cell line MDA-MB-468 of the palindromic peptide LfcinB (21–25)_Pal: ¹RWQWRWQWR⁹ and its analogous peptides, obtained via alanine scanning, was evaluated. The results indicate that the palindromic peptide exhibited a concentration-dependent cytotoxic effect against this cell line. The cytotoxic effect of the palindromic peptide was fast and selective and was sustained for up to 48 h of treatment. MDA-MB-468 cells treated with the palindromic peptide exhibited severe cellular damage, acquiring rounded forms and shrinkage, a behavior typical of apoptotic events. The analogous peptides exhibited fewer cytotoxic effects than the original palindromic peptide, suggesting that the substitution of any amino acid with alanine diminishes the cytotoxic effect. The Arg and Trp residues proved to be the most relevant for the cytotoxic effect; the analogous peptides with substitutions of Trp with Ala did not induce a change in cellular morphology, while analogous peptides with substitutions of Arg or Gln with Ala induced cellular damage. Also, neither the palindromic peptide nor its analogues exerted a significant cytotoxic effect on normal fibroblasts, indicating that the peptides had a selective cytotoxic effect on cancerous cells. The peptide LfcinB (21–25)_Pal, and its analogues exhibited antibacterial activity against E. coli and S. aureus strains and a selective cytotoxic effect against the breast cancer cell line MDA-MB-468.

The cytotoxic effect against the breast cancer cell line MDA-MB-468 of the palindromic peptide LfcinB (21–25)_Pal: ¹RWQWRWQWR⁹ and its analogous peptides, obtained via alanine scanning, was evaluated.

Copper or Manganese Supplementation Endows the Peptic Hydrolysate from Bovine Lactoferrin with Enhanced Activity to Human Gastric Cancer AGS Cells

A lactoferrin hydrolysate (LFH) was generated from bovine lactoferrin by pepsin, mixed with Cu²⁺ and Mn²⁺ at 0.64-1.28 and 0.28-0.56 mg/g protein, respectively; and then their in vitro effects on human gastric cancer AGS cells were assessed. With incubation times of 24 or 48 h, LFH and its Cu²⁺/Mn²⁺ mixtures at 10-30 mg/mL in dose-dependent manner inhibited cell growth; and more, these mixtures showed higher activities than LFH alone. Cell treatments of LFH and the mixtures (25 mg/mL) for 24 h could arrest cell cycle at G0/G1-phase, damage mitochondrial membrane integrity, and induce apoptosis, while the mixtures were also more powerful than LFH to exert these three effects. Higher Cu²⁺/Mn²⁺ supplementation level resulted in higher growth inhibition, cell cycle arrest, mitochondrial membrane potential disruption, and apoptosis induction; furthermore, Mn²⁺ was notable for its higher efficacy than Cu²⁺ to increase these four effects. Western-blot assay results revealed that four apoptosis-related proteins Bad, Bax, cytochrome c, and p53 were up-regulated, and both caspase-3 and caspase-9 also were cleaved and activated; moreover, two autophagy-related proteins LC3-II and cleaved Beclin-1 were down- and up-regulated, respectively. It is thus concluded that Cu²⁺ and especially Mn²⁺ could endow supplemented LFH with increased anti-cancer effects in AGS cells, with two proposed events as enhanced apoptosis induction (via activating apoptosis-related proteins) and autophagy inhibition (via activating autophagy-related proteins).

Dairy foods and positive impact on the consumer's health

The objective of the present chapter was to demonstrate the state of the art in the recent advances in nutritional and functional components of dairy products research. In this chapter, the main mechanisms responsible and essential for a better understanding of nutritional and functional values of the components of milk and dairy products are highlighted. It also includes a discussion about the positive impacts of fermented milk, cheese, butter, ice cream, and dairy desserts components on the consumer's health.

Effect of Cu/Mn-Fortification on In Vitro Activities of the Peptic Hydrolysate of Bovine Lactoferrin against Human Gastric Cancer BGC-823 Cells

Bovine lactoferrin hydrolysate (BLH) was prepared with pepsin, fortified with Cu2+ (Mn2+) 0.64 and 1.28 (0.28 and 0.56) mg/g protein, and then assessed for their activity against human gastric cancer BGC-823 cells. BLH and the four fortified BLH products dose- and time-dependently had growth inhibition on the cells in both short- and long-time experiments. These samples at dose level of 25 mg/mL could stop cell-cycle progression at the G0/G1-phase, damage mitochondrial membrane, and induce cell apoptosis. In total, the fortified BLH products had higher activities in the cells than BLH alone. Moreover, higher Cu/Mn fortification level brought higher effects, and Mn was more effective than Cu to increase these effects. In the treated cells, the apoptosis-related proteins such as Bad, Bax, p53, cytochrome c, caspase-3, and caspase-9 were up-regulated, while Bcl-2 was down-regulated. Caspase-3 activation was also evidenced using a caspase-3 inhibitor, z-VAD-fmk. Thus, Cu- and especially Mn-fortification of BLH brought health benefits such as increased anti-cancer activity in the BGC-823 cells via activating the apoptosis-related proteins to induce cell apoptosis.

How are the expression patterns of gut antimicrobial peptides modulated by human gastrointestinal diseases? A bridge between infectious, inflammatory, and malignant diseases

The human gut barrier is the tissue exposed to the highest load of microorganisms, harbouring 100 trillion bacteria. In addition, the gut's renewal rate outruns that of any other human tissue. Antimicrobial peptides (AMPs) are highly optimized defense molecules in the intestinal barrier optimized to maintain gastrointestinal homeostasis. Alterations in AMPs activity can lead to or result from human gastrointestinal diseases. In this review, unique, conserved, or otherwise regular alterations in the expression patterns of human AMPs across gastrointestinal inflammatory and infectious diseases were analyzed for pattern elucidation. Human gastrointestinal diseases are associated with alterations in gut AMPs' expression patterns in a peptide-specific, disease-specific, and pathogen-specific way, modulating human gastrointestinal functioning. Across diseases, there is a (i) marked reduction in otherwise constitutively expressed AMPs, leading to increased disease susceptibility, and a (ii) significant increase in the expression of inducible AMPs, leading to tissue damage and disease severity. Infections and inflammatory conditions are associated with altered gene expression in the gut, whose patterns may favour cellular metaplasia, mucosal dysfunction, and disease states. Altered expression of AMPs can thus thrive disease severity and evolution since its early stages. Nevertheless, the modulation of AMP expression patterns unveils promising therapeutic targets.

A cytosol derived factor of Group B streptococcus prevent its invasion into human epithelial cells

Group B streptococcus (GBS) or Streptococcus agalactiae, is an opportunistic pathogen causing a wide range of infections like pneumonia, sepsis, and meningitis in newborn, pregnant women and adults. While this bacterium has adapted well to asymptomatic colonization of adult humans, it still remains a potentially devastating pathogen to susceptible infants. Advances in molecular techniques and refinement of in vitro and in vivo model systems have elucidated key elements of the pathogenic process, from initial attachment to the maternal vaginal epithelium to penetration of the newborn blood-brain barrier. Still, the formidable array of GBS virulence factors makes this bacterium at the forefront of neonatal pathogens. The involvement of bacterial components in the host-pathogen interaction of GBS pathogenesis and its related diseases is not clearly understood. In this study we demonstrated the role of a 39 kDa factor from GBS which plays an important role in the process of its invasion. We found a homogeneous 39 kDa factor from the cytosol of GBS after following a combination of sequential purification steps involving molecular sieving and ion exchange chromatography using ACTA-FPLC system. Its N-terminal sequence showed a homology with xenobiotic response element type transcriptional regulator protein, a 40 kDa protein of Streptococcus. This factor leads to inhibition of GBS invasion in HeLa and A549 cells. This protein also showed sensitivity and specific cross reactivity with the antibodies raised against it in New Zealand white rabbits by western immunoblotting. This inhibitory factor was further confirmed tolerant for its cytotoxicity. These results add a novel aspect to bacterial pathogenesis where bacteria's own intracellular protein component can act as a potential therapeutic candidate by decreasing the severity of disease thus promoting its invasion inhibition.

Positive Expression of SMYD2 is Associated with Poor Prognosis in Patients with Primary Hepatocellular Carcinoma

Purpose: SET and MYND domain-containing protein2 (SMYD2), a histone lysine methyltransferases, is a candidate human oncogene in multiple tumors. However, the expression dynamics of SMYD2 in hepatocellular carcinoma (HCC) and its clinical/prognostic significance are unclear.

Methods: The SMYD2 expression profile was examined by quantitative real-time polymerase chain reaction (qRT-PCR), and immunohistochemistry (IHC) in HCC tissues and matched adjacent non-tumorous tissues. SMYD2 was silenced in HCC cell lines to determine its role in tumor proliferation and cell cycle progression, and the possible mechanism. Spearman's rank correlation, Kaplan-Meier plots and Cox proportional hazards regression model were used to analyze the data.

Results: The SMYD2 expression in HCC tissues were significantly up-regulated at both mRNA and protein levels as compared with the matched adjacent non-tumorous tissues. By IHC, positive expression of SMYD2 was examined in 122/163 (74.85%) of HCC and in 10/59 (16.95%) of tumor-adjacent tissues. Positive expression of SMYD2 was correlated with tumor size, vascular invasion, differentiation and TNM stage (P < 0.05). In univariate survival analysis, a significant association between positive expression of SMYD2 and shortened patients' survival was found (P < 0.05). Importantly, SMYD2 expression together with vascular invasion (P < 0.05) provided significant independent prognostic parameters in multivariate analysis. Functionally, SMYD2 silenced markedly inhibited cell proliferation and cell cycle progression in SMMC-7721 cell.

Conclusions: Our findings provide evidences that positive expression of SMYD2 in HCC may be important in the acquisition of an aggressive phenotype, and it is an independent biomarker for poor prognosis of patients with HCC.

Apoptotic effects of bovine apo-lactoferrin on HeLa tumor cells

Lactoferrin (Lf), a cationic iron-binding glycoprotein of 80 kDa present in body secretions, is known as a compound with marked antimicrobial activity. In the present study, the apoptotic effect of iron-free bovine lactoferrin (apo-bLf) on human epithelial cancer (HeLa) cells was examined in association with reactive oxygen species and glutathione (GSH) levels. Apoptotic effect of iron-free bovine lactoferrin inhibited the growth of HeLa cells after 48 hours of treatment while the diferric-bLf was ineffective in the concentration range tested (from 1 to 12.5 μM). Western blot analysis showed that key apoptotic regulators including Bax, Bcl-2, Sirt1, Mcl-1, and PARP-1 were modulated by 1.25 μM of apo-bLf. In the same cell line, apo-bLf induced apoptosis together with poly (ADP-ribose) polymerase cleavage, caspase activation, and a significant drop of NAD⁺ . In addition, apo-bLf-treated HeLa cells showed a marked increase of reactive oxygen species level and a significant GSH depletion. On the whole, apo-bLf triggered apoptosis of HeLa cells upon oxygen radicals burst and GSH decrease.

Lactoferrin from Milk: Nutraceutical and Pharmacological Properties

Lactoferrin is an iron-binding protein present in large quantities in colostrum and in breast milk, in external secretions and in polymorphonuclear leukocytes. Lactoferrin's main function is non-immune protection. Among several protective activities shown by lactoferrin, those displayed by orally administered lactoferrin are: (i) antimicrobial activity, which has been presumed due to iron deprivation, but more recently attributed also to a specific interaction with the bacterial cell wall and extended to viruses and parasites; (ii) immunomodulatory activity, with a direct effect on the development of the immune system in the newborn, together with a specific antinflammatory effects; (iii) a more recently discovered anticancer activity. It is worth noting that most of the protective activities of lactoferrin have been found, sometimes to a greater extent, also in peptides derived from limited proteolysis of lactoferrin that could be generated after lactoferrin ingestion. Lactoferrin could therefore be considered an ideal nutraceutic product because of its relatively cheap production from bovine milk and of its widely recognized tolerance after ingestion, along with its well demonstrated protective activities. The most important protective activities shown by orally administered bovine lactoferrin are reviewed in this article.

BCL-3 promotes the tumor growth of hepatocellular carcinoma by regulating cell proliferation and the cell cycle through cyclin D1

Previous studies have demonstrated the aberrant expression and oncogenic role of B-cell CLL/lymphoma-3 (BCL-3) in human malignancies. However, the clinical significance of BCL-3 and its biological function in human hepatocellular carcinoma (HCC) remain unknown. In the present study, the expression levels of BCL-3 protein and mRNA in 90 pairs of HCC and matched non-tumor tissues were analyzed using immunohistochemistry and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). We found that the expression levels of BCL-3 protein and mRNA in HCC tissues were significantly higher than those in the matched tumor-adjacent tissues. In addition, positive expression of BCL-3 was associated with adverse clinicopathological characteristics of the HCC patients including hepatitis B virus (HBV) infection, tumor size, cirrhosis and advanced tumor-node-metastasis (TNM) stage. Moreover, HCC patients with positive expression of BCL-3 had significantly decreased 5-year overall survival and recurrence-free survival. Importantly, BCL-3 expression was an independent prognostic factor for indicating the survival of the HCC patients. Functionally, BCL-3 knockdown markedly inhibited cell viability, proliferation and cell cycle progression in HepG2 cells, while BCL-3 overexpression promoted these cellular processes in Huh7 cells. Accordingly, in vivo experiments indicated that BCL-3 knockdown prominently suppressed the tumor growth of HepG2 cells in nude mice. Mechanistically, we revealed that the expression of cyclin D1 was decreased after BCL-3 knockdown in the HepG2 cells and was increased after BCL-3 overexpression in the Huh7 cells. Cyclin D1 silencing was found to abrogate the functional effects of BCL-3 on cellular processes in Huh7 cells. Taken together, our data suggest that BCL-3 may serve as a promising biomarker and an effective therapeutic target of HCC.

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.

Comparison of Proliferative Effect of Human Lactoferrin and Its Proteolytic Peptide on Normal and Transformed Epithelial Cells

Human lactoferrin (hLF) is an iron-binding glycoprotein with a variety of functions. hLF undergoes proteolytic cleavage to smaller peptides in the stomach following ingestion. In the present study, we evaluated the effects of hLF and its proteolytic product, human lactoferrin peptide (hLFP), on the proliferation of two epithelial cells, HEK293 normal cells and KATO III gastric carcinoma cells, using an MTT assay and expression of proliferative nuclear cell antigen (PCNA), a notable proliferation marker. When the two epithelial cells were stimulated with hLF and hLFP in the presence of fetal bovine serum (FBS), hLFP stimulated proliferation of both cell types at lower concentrations than hLF by two orders of magnitude. The cancer cells exhibited proliferative responses to both hLF and hLFP at lower concentrations by 2∼3 orders of magnitude than the normal cells. Either hLF or hLFP alone did not support appreciable proliferation of these cell lines in the absence or low concentrations of FBS. Bovine serum albumin or its proteolytic product failed to promote cellular proliferation even in the presence of 10 % FBS, indicating the specificity of the proliferative activity of hLF and hLFP. These data highlight feasibility of hLF and its peptide for adjuvants for tissue culture medium.

In vitro and in vivo effect of human lactoferrin on glioblastoma growth

OBJECT

Human lactoferrin (HLF) is a natural protein with antitumor activity. The aim of this study was to investigate the effects of HLF alone and in combination with temozolomide (TMZ), a conventional chemotherapeutic, on human glioblastoma (GBM) cells.

METHODS

The authors cultured fresh human primary cell lines NMD and FN and the continuous cell line U87MG to evaluate proliferation in the presence of HLF alone at different doses (1, 10, and 100 mg/ml, and 1 mg/ml) and in combination with TMZ. In in vivo experiments they assessed tumor size reduction in CD1 nude mice carrying an orthotopic GBM xenograft and orally treated with HLF.

RESULTS

Lactoferrin causes growth inhibition in the NMD and FN primary cell lines and in the U87MG continuous cell line. This inhibition seemed to be modulated by the downregulation of cyclin D1 and D4. Western blot and fluorescence-activated cell sorting analysis showed inhibition of the cell cycle in G0/G1 and G2 phases. When administered in nude mice, HLF (60 mg/kg/day) decreased tumor size about 30%, as shown in both histological analyses and high-field brain MRI. Administration of HLF with TMZ enhanced the effect of chemotherapy both in vitro and in vivo.

CONCLUSIONS

This study demonstrated that HLF can inhibit GBM cell growth, suggesting that this nontoxic substance may have a role in potentiating the effect of current TMZ treatment of GBM.

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.

Milk proteins, peptides, and oligosaccharides: effects against the 21st century disorders

Milk is the most complete food for mammals, as it supplies all the energy and nutrients needed for the proper growth and development of the neonate. Milk is a source of many bioactive components, which not only help meeting the nutritional requirements of the consumers, but also play a relevant role in preventing various disorders. Milk-derived proteins and peptides have the potential to act as coadjuvants in conventional therapies, addressing cardiovascular diseases, metabolic disorders, intestinal health, and chemopreventive properties. In addition to being a source of proteins and peptides, milk contains complex oligosaccharides that possess important functions related to the newborn's development and health. Some of the health benefits attributed to milk oligosaccharides include prebiotic probifidogenic effects, antiadherence of pathogenic bacteria, and immunomodulation. This review focuses on recent findings demonstrating the biological activities of milk peptides, proteins, and oligosaccharides towards the prevention of diseases of the 21st century. Processing challenges hindering large-scale production and commercialization of those bioactive compounds have been also addressed.

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.

Norspermidine and novel Pd(II) and Pt(II) polynuclear complexes of norspermidine as potential antineoplastic agents against breast cancer

Background

New strategies are needed for breast cancer treatment and one initial step is to test new chemotherapeutic drugs in breast cancer cell lines, to choose candidates for further studies towards clinical use.

Methodology and Findings

The cytotoxic effects of a biogenic polyamine analogue – norspermidine – and its trinuclear Pd(II) and Pt(II) complexes – Pd₃NSpd₂ and Pt₃NSpd₂, respectively – were investigated in one immortalized normal-like and three breast cancer cell lines. The normal-like MCF-10A cells were least sensitive to the compounds, while growth inhibition and cell death was observed in the cancer cell lines. Norspermidine and its Pd(II) complex were generally shown to have stronger antiproliferative effects than the corresponding Pt(II) complex. Moreover, both norspermidine and the Pd(II) complex reduced the cellular activity of the growth-related enzyme, ornithine decarboxylase (ODC) to a lower level than the Pt(II) complex in most of the cell lines examined. Treatment with norspermidine or the Pd(II) complex reduced the number of colonies formed in a soft agar assay performed with the breast cancer cell lines, indicating that these compounds reduced the malignancy of the breast cancer cells. The effect of norspermidine or the Pd(II) complex on colony formation was much stronger than that observed for the Pt(II) complex. The results from a new mammalian genotoxicity screen together with those of a single cell gel electrophoresis assay indicated that none of the drugs were genotoxic at a 25 µM concentration.

Main Conclusions

Overall, norspermidine and its Pd(II) complex were shown to have strong antiproliferative effects. In comparison, the effects obtained with the Pd(II) complex were much stronger than that of the Pt(II) complex. The results obtained in the present study demonstrate that the trinuclear Pd(II) complex of norspermidine (Pd₃NSpd₂) may be regarded as a potential new metal-based drug against breast cancer, coupling a significant efficiency to a low toxicity.

Recombinant expression, purification, and antimicrobial activity of a novel hybrid antimicrobial peptide LFT33

With great therapeutic potential against antibiotic-resistant bacteria, viruses, and even parasites, antimicrobial peptides (AMPs) have received increased interest as pharmaceutical agents in recent years. It is a worthy yet challenging work to carry out the implement and improvement of AMPs production using bioengineering techniques. In the present study, a novel hybrid peptide LFT33 was designed derived from LfcinB and thanatin. The cDNA fragment encoding LFT33 with preferred codons of Escherichia coli was chemically synthesized and ligated into the vector pET32a(+) to express the LFT33 fusion protein. The fusion protein was successfully expressed in soluble form in E. coli induced under optimized conditions. After purification by affinity chromatography, the fusion protein was cleaved successfully by enterokinase and released the peptide LFT33. About 0.5 mg of the recombinant LFT33 was obtained by reversed-phase high performance liquid chromatography from 1 l of culture medium. Mass spectrometry analysis of the purified recombinant LFT33 demonstrated that the molecular weight perfectly matched the calculated mass (4,195 Da). The recombinant peptide LFT33 caused an increase in antimicrobial activity (IC(50) = 16-64 μg/ml) against given strains and did not show hemolytic activity for human erythrocytes. The results indicated that the hybrid peptide LFT33 could serve as a promising candidate for pharmaceutical agents.

The effect of bovine milk lactoferrin on human breast cancer cell lines

The evidence that biologically active food components are key environmental factors affecting the incidence of many chronic diseases is overwhelming. However, the full extent of such components in our diet is unknown, as is our understanding of their mechanisms of action. Beyond the interaction of these food components with the gut and intestinal immune functions, whey proteins such as lactoferrin are being tested as anticancer agents. Lactoferrin is an iron-binding protein that has been reported to inhibit several types of cancer. In the present work, the effects of bovine milk lactoferrin on human breast cancer HS578T and T47D cells were studied. The cells were either untreated or treated with lactoferrin concentrations ranging from 0.125 to 125 μM. Lactoferrin decreased the cell viability of HS578T and T47D by 47 and 54%, respectively, and increased apoptosis about 2-fold for both cell lines. Proliferation rates decreased by 40.3 and 63.9% for HS578T and T47D, respectively. For the T47D line, cell migration decreased in the presence of the protein. Although the mechanisms of action are not fully known, the results gathered in this work suggest that lactoferrin interferes with some of the most important steps involved in cancer development.

Effect of bovine lactoferricin on DNA methyltransferase 1 levels in Jurkat T-leukemia cells

Abnormal methylation of the promoter of several genes is common in patients with acute lymphoblastic leukemia. Methylation of DNA is brought about by DNA methyltransferases (DNMT). Bovine lactoferricin (Lfcin B) is a cationic peptide that possesses potent in vitro and in vivo anticancer activity and might affect the expression of DNMT1. In the current study, we determined the mRNA and protein expression of DNMT1 in Jurkat T-leukemia cells, after incubation with Lfcin B, by real-time quantitative reverse transcription PCR and Western blot analysis. The results of real-time quantitative reverse transcription PCR showed that DNMT1 expression in Jurkat T-leukemia cells was reduced after treatment with Lfcin B, and Lfcin B reduced the half-life of DNMT1 mRNA from approximately 8 to 2h. The results of Western blot analysis showed that the expression of DNMT1 protein was down-modulated by Lfcin B in Jurkat T-leukemia cells. Moreover, we found that protein biosynthesis in Jurkat T-leukemia cells was essential for Lfcin B to down-modulate the expression of DNMT1.