Surface nucleolin participates in both the binding and endocytosis of lactoferrin in target cells

Spleen-Heart Cross-Talk Through CD23-Mediated Signal Promotes Cardiac Remodeling

BACKGROUND

Elevated levels of IgE are implicated in pathological cardiac remodeling. However, the origin of IgE remains unknown. In the current study, we aim to explore the source of IgE and the mechanisms underlying IgE production in the context of pathological cardiac remodeling.

METHODS

Flow cytometry was used to assess the changes of IgE-producing B cells in different organs/tissues, including the spleen, lymph nodes, bone marrow, peripheral blood, vasculature, and heart, in mice with cardiac remodeling induced by transverse aortic constriction (TAC). The role of IgE low-affinity receptor FcεRII (also named CD23) in IgE-producing B cells during cardiac remodeling was evaluated in mice with loss-of-CD23 or gain-of-CD23. The therapeutic potential of the CD23-neutralizing antibody was evaluated. The factors involved in organ cross-talk, which regulate IgE production, were identified and validated both in vitro and in vivo.

RESULTS

We found that splenic IgE-producing cells were significantly elevated in the TAC mice. CD23, as a negative regulator of IgE production, was decreased in splenic B cells of TAC mice. Global knockout of CD23 in mice aggravated TAC-induced IgE synthesis and cardiac remodeling in vivo. In contrast, global or B-cell-specific CD23 overexpression in mice reduced IgE synthesis and alleviated TAC-induced cardiac remodeling. Mechanistically, CD23 was cleaved by ADAM10 (A disintegrin and metalloproteinase domain 10) in the spleen. Screening assay with data-independent acquisition mass spectrometry-based proteomics and ELISA identified Ltf (lactotransferrin), released from the heart shortly after TAC stimulation, as a contributor to ADAM10 upregulation through binding to Ltf receptor Ncl (nucleolin). Meanwhile, Ltf administration promoted IgE elevation, accompanied by increased ADAM10 expression and decreased CD23 expression in vitro and in vivo. Furthermore, the plasma Ltf levels were positively correlated with TAC-induced cardiac remodeling, serum IgE, and sCD23 (soluble CD23). Consistently, Ltf levels were elevated in patients with heart failure with reduced ejection fraction and also positively correlated with serum IgE and sCD23.

CONCLUSIONS

Our findings indicate a critical role of the Ltf-ADAM10-CD23 axis in regulating IgE production through cross-talk between the heart and spleen. The Ltf-ADAM10-CD23 axis may represent new molecular targets for IgE-mediated pathological cardiac remodeling.

Anticancer potential of lactoferrin: effects, drug synergy and molecular interactions

Cancer treatment is among today's most active and challenging research fields. In recent years, significant progress has been made in developing new cancer therapies, including nutraceuticals and natural compounds with anticancer properties. Lactoferrin, a glycoprotein present in mammals, is of significant interest due to its pleiotropic behavior, demonstrating a broad spectrum of biological activities such as antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, and anticancer effects. In this review, we examine the current knowledge of Lf's role in cancer. In addition, it exhibits a synergistic effect along with conventional drugs, potentially enhancing their efficacy and, at the same time, reducing the side effects associated with most traditional therapies. However, it is essential to consider the precise molecular mechanism by which Lf exerts its antitumor activity. Searching interactions with several molecules can provide insight into this mechanism. Additionally, finding lactoferrin receptors can improve the strategies for the specific release of the conjugates. For all these reasons, Lactoferrin becomes a potential therapeutic agent that should be examined in depth.

Bovine Lactoferrin Enhances Toll-like Receptor 7 Response in Plasmacytoid Dendritic Cells and Modulates Cellular Immunity

Plasmacytoid dendritic cells (pDCs) express Toll-like receptor 7 (TLR7) in the endosomes, recognize viral single-stranded RNA (ssRNA), and produce significant amounts of interferon (IFN)-α. Bovine lactoferrin (LF) enhances the response of IFN regulatory factors followed by the activation of IFN-sensitive response elements located in the promoter regions of the IFN-α gene and IFN-stimulated genes in the TLR7 reporter THP-1 cells in the presence of R-848, a TLR7 agonist. In ex vivo experiments using human peripheral blood mononuclear cells, LF enhances IFN-α levels in the supernatant in the presence of R-848. Additionally, it increases the expression of IFN-α, human leukocyte antigen (HLA)-DR, and CD86 in pDCs; HLA-DR and CD86 in myeloid dendritic cells; CD69 in CD56 dim natural killer and T killer cells; and IFN-γ in T helper type 1 and B cells in the presence of R-848. The inhibition of phagocytosis or neutralization of nucleolin, a receptor of LF, suppresses LF incorporation into pDCs. These results suggest that pDCs incorporate LF through phagocytosis or nucleolin-mediated endocytosis, and LF enhances TLR7 response in the endosome and subsequent IFN signaling pathway and activates innate and adaptive immune cells. We anticipate that LF modulates antiviral immunity against environmental ssRNA viruses and contributes to homeostasis.

Controversial role of lactoferrin in cancer: A narrative review

Lactoferrin (Lf) is a positively charged iron-binding glycoprotein that has piqued the scientific community's interest due to its pleiotropic behavior, exhibiting a wide range of biological activities, including antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, and anticancer effects. This narrative review explores the current understanding of Lf's role in cancer, focusing on the endogenously expressed human full-length and ΔLf isoforms, and the effects of treatment with exogenous human and bovine Lf. We evaluated and compared the mechanisms by which Lf influences tumorigenesis and cancer progression, focusing on its impact on key processes such as cell growth, apoptosis, angiogenesis, cell migration, and invasiveness. Notably, the mechanisms of action of human and bovine Lf show some divergences, presumably due to slight structural differences that may lead to opposing effects. Insights from this comparison may help identify new Lf variants with enhanced anticancer activity. Indeed, both human and bovine Lf showed substantial anticancer activity, prompting researchers to investigate their potential utility in cancer prevention and progression. However, some studies have indicated that high levels of human Lf expression may be linked to increased carcinogenesis and metastasis, reflecting its intricate and context-dependent role in cancer. Thus, we emphasize the need for a deeper comprehension of Lf biology and its regulation to enhance understanding of Lf's role in cancer and identify more targeted therapeutic strategies, encouraging further research in this area.

Immunologic Effects of a Novel Bovine Lactoferrin-Derived Peptide on the Gut and Clinical Perspectives

Bovine lactoferrin is a natural iron-binding glycoprotein known for its antimicrobial, antiviral, antitumor, anti-inflammatory, and immunomodulatory properties. In this study, we artificially recombined a fragment of bovine lactoferrin with immunomodulatory and antimicrobial properties to create a novel peptide named LF-MQL. The primary objective was to investigate the effects of LF-MQL on the intestinal tract and immune cells in animals. First, we assessed the in vitro activation effects of LF-MQL on mouse peritoneal macrophages. The results indicated that LF-MQL enhanced the macrophage phagocytic activity and increased IL-1β mRNA expression without significantly affecting IL-6 mRNA levels. Next, we examined the effects of LF-MQL on mucosal immunity by administering LF-MQL orally at doses of 300 mg/kg, 30 mg/kg, and 3 mg/kg to mice. The results demonstrated that different doses of LF-MQL modulated IL-6 and IL-10 mRNA levels in the small intestine. Low doses enhanced the intestinal immune response, while higher doses reduced the inflammatory response. In conclusion, LF-MQL exerts immunomodulatory effects rather than simply boosting immune activity in animal models.

Japanese encephalitis virus NS5 protein interacts with nucleolin to enhance the virus replication

Japanese encephalitis virus (JEV) is an arthropod-borne, plus-strand flavivirus causing viral encephalitis in humans with a high case fatality rate. The JEV non-structural protein 5 (NS5) with the RNA-dependent RNA polymerase activity interacts with the viral and host proteins to constitute the replication complex. We have identified the multifunctional protein Nucleolin (NCL) as one of the several NS5-interacting host proteins. We demonstrate the interaction and colocalization of JEV NS5 with NCL in the virus-infected HeLa cells. The siRNA-mediated knockdown of NCL indicated that it was required for efficient viral replication. Importantly, JEV grew to higher titers in cells over-expressing exogenous NCL, demonstrating its pro-viral role. We demonstrated that NS5 interacted with the RRM and GAR domains of NCL. We show that the NCL-binding aptamer AS1411 containing the G-quadruplex (GQ) structure and the GQ ligand BRACO-19 caused significant inhibition of JEV replication. The antiviral effect of AS1411 and BRACO-19 could be overcome in HeLa cells by the overexpression of exogenous NCL. We demonstrated that the synthetic RNAs derived from the 3'-NCR of JEV genomic RNA containing the GQ sequence could bind NCL in vitro. The replication complex binding to the 3'-NCR is required for the viral RNA synthesis. It is likely that NCL present in the replication complex destabilizes the GQ structures in the genomic RNA, thus facilitating the movement of the replication complex resulting in efficient virus replication.IMPORTANCEJapanese encephalitis virus (JEV) is endemic in most parts of South-East Asia and the Western Pacific region, causing epidemics of encephalitis with a high case fatality rate. While a tissue culture-derived JEV vaccine is available, no antiviral therapy exists. The JEV NS5 protein has RNA-dependent RNA polymerase activity. Together with several host and viral proteins, it constitutes the replication complex necessary for virus replication. Understanding the interaction of NS5 with the host proteins could help design novel antivirals. We identified Nucleolin (NCL) as a crucial host protein interactor of JEV NS5 having a pro-viral role in virus replication. The NS5-interacting NCL binds to the G-quadruplex (GQ) structure sequence in the 3'-NCR of JEV RNA. This may smoothen the movement of the replication complex along the genomic RNA, thereby facilitating the virus replication. This study is the first report on how NCL, a host protein, helps in JEV replication through GQ-binding.

TLR4 TIR domain and nucleolin GAR domain synergistically mediate RSV infection and induce neuronal inflammatory damage in SH-SY5Y cells

Previous research results of our group showed that Toll-like receptor 4 (TLR4) and nucleolin synergistically mediate respiratory syncytial virus (RSV) infection in human central neuron cells, but the specific mechanism remains unclear. Here we designed and synthesized lentiviruses with TIR (674-815 aa), TLR4 (del 674-815 aa), GAR (645-707 aa), and NCL (del 645-707 aa) domains, and obtained stable overexpression cell lines by drug screening, and subsequently infected RSV at different time points. Laser confocal microscopy and coimmunoprecipitation were used for the observation of co-localization and interaction of TIR/GAR domains. Western blot analysis was used for the detection of p-NF-κB and LC3 protein expression. Real-time PCR was used for the detection of TLR4/NCL mRNA expression. ELISA assay was used to measure IL-6, IL-1β, and TNF-α concentrations and flow cytometric analysis was used for the study of apoptosis. Our results suggest that overexpression of TIR and GAR domains can exacerbate apoptosis and autophagy, and that TIR and GAR domains can synergistically mediate RSV infection and activate the NF-κB signaling pathway, which regulates the secretion of downstream inflammatory factors, such as IL-6, IL-1β, and TNF-α, and ultimately leads to neuronal inflammatory injury.

Tumor diagnosis using carbon-based quantum dots: Detection based on the hallmarks of cancer

Carbon-based quantum dots (CQDs) have been shown to have promising application value in tumor diagnosis. Their use, however, is severely hindered by the complicated nature of the nanostructures in the CQDs. Furthermore, it seems impossible to formulate the mechanisms involved using the inadequate theoretical frameworks that are currently available for CQDs. In this review, we re-consider the structure-property relationships of CQDs and summarize the current state of development of CQDs-based tumor diagnosis based on biological theories that are fully developed. The advantages and deficiencies of recent research on CQDs-based tumor diagnosis are thus explained in terms of the manifestation of nine essential changes in cell physiology. This review makes significant progress in addressing related problems encountered with other nanomaterials.

Milk Antiviral Proteins and Derived Peptides against Zoonoses

Milk is renowned for its nutritional richness but also serves as a remarkable reservoir of bioactive compounds, particularly milk proteins and their derived peptides. Recent studies have showcased several robust antiviral activities of these proteins, evidencing promising potential within zoonotic viral diseases. While several publications focus on milk's bioactivities, antiviral peptides remain largely neglected in reviews. This knowledge is critical for identifying novel research directions and analyzing potential nutraceuticals within the One Health context. Our review aims to gather the existing scientific information on milk-derived antiviral proteins and peptides against several zoonotic viral diseases, and their possible mechanisms. Overall, in-depth research has increasingly revealed them as a promising and novel strategy against viruses, principally for those constituting a plausible pandemic threat. The underlying mechanisms of the bioactivity of milk's proteins include inhibiting viral entry and attachment to the host cells, blocking replication, or even viral inactivation via peptide-membrane interactions. Their marked versatility and effectiveness stand out compared to other antiviral peptides and can support future research and development in the post-COVID-19 era. Overall, our review helps to emphasize the importance of potentially effective milk-derived peptides, and their significance for veterinary and human medicines, along with the pharmaceutical, nutraceutical, and dairy industry.

BIOINFORMATICS APPLICATIONS UNDER CONDITION CONTROL: HIGH DIAGNOSTIC VALUE OF DDX47 IN REAL MEDICAL SETTINGS

ABSTRACT

Sepsis is an organ dysfunction caused by a dysregulated host response to infection and remains an ongoing threat to human health worldwide. Septic shock is the most severe subset of sepsis as characterized by abnormalities in cells, circulation, and metabolism. As a time-dependent condition, early recognition allowing appropriate therapeutic measures to be started in a timely manner becomes the most effective way to improve prognosis. However, because of the lack of a criterion standard, most diagnoses merely rely on medical history, empirical diagnosis, and blood culture results. Gene expression profiles have specific diagnostic value, as they reflect a subjective host response to pathogens. We propose a method, Condition Control based on Real-life Medical Scenarios, to control for factors in realistic medical scenarios. Restricted variables are used as much as possible to identify unique differential genes and progressively test their diagnostic value by relaxing restrictions. In total, three data sets were included in the study; the first two data sets were from the Gene Expression Omnibus database, and the third involved patients who were diagnosed with sepsis or septic shock within 7 days of admission to the intensive care unit at West China Hospital of Sichuan University from 2020 to 2021. DDX47 showed preferable diagnostic value in various scenarios, especially in patients with common infections or sepsis and septic shock. Here we also show that hub genes may regulate immune function and immune cell counts through the interaction of different apoptotic pathways and immune checkpoints based on the high correlation. DDX47 is closely associated with B cells according to single-cell sequencing results.

DNA-based molecular recognition system for lactoferrin biosensing

The paper describes the development of a novel DNA oligonucleotide-based affinity bioreceptor that binds to lactoferrin, a glycoprotein-type immunomodulator. The research was performed using surface plasmon resonance method to investigate affinity of various types of oligonucleotides to the target protein. The 72 base pair-long 5'[(TAGAGGATCAAA)AAA]4TAGAGGATCAAA3' sequence with the highest affinity to lactoferrin was selected for further investigations. Kinetic analysis of the interaction between selected DNA and lactoferrin provided rate and equilibrium constants: ka = (2.49 ± 0.03)∙104 M-1∙s-1, kd = (1.89 ± 0.02)∙10-3 s-1, KA = (0.13 ± 0.05)∙108 M-1, and KD = (7.61 ± 0.18)∙10-8 M. Thermodynamic study conducted to determine the ΔH0, ΔS0, and ΔG0 for van't Hoff characteristic in the temperature range of 291.15-305.15 K, revealed the complex formation as endothermic and entropically driven. The chosen DNA sequence's selectivity towards lactoferrin was confirmed with interferents' response constituting <3 % of the response to lactoferrin. SPR analysis justified utility of the designed DNA oligonucleotide for Lf determination, with LOD of 4.42∙10-9 M. Finally, the interaction between lactoferrin and DNA was confirmed by electrochemical impedance spectroscopy, providing the basis for further quantitative assay of lactoferrin using the developed DNA-based bioreceptor. The interactions were performed under immobilized DNA ligand conditions, thus reflecting the sensor's surface, which facilitates their transfer to other label-free biosensor technologies.

Nucleolin‑based targeting strategies in cancer treatment: Focus on cancer immunotherapy (Review)

The benefits of treating several types of cancers using immunotherapy have recently been established. The overexpression of nucleolin (NCL) in a number of types of cancer provides an attractive antigen target for the development of novel anticancer immunotherapeutic treatments. NCL is a multifunctional protein abundantly distributed in the nucleus, cytoplasm and cell membrane. It influences carcinogenesis, and the proliferation, survival and metastasis of cancer cells, leading to cancer progression. Additionally, the meta‑analysis of total and cytoplasmic NCL overexpression indicates a poor prognosis of patients with breast cancer. The AS1411 aptamers currently appear to have therapeutic action in the phase II clinical trial. The authors' research group has recently explored the anticancer function of NCL through the activation of T cells by dendritic cell‑based immunotherapy. The present review describes and discusses the mechanisms through which the multiple functions of NCL can participate in the progression of cancer. In addition, the studies that define the utility of NCL‑dependent anticancer therapies are summarized, with specific focus being paid to cancer immunotherapeutic approaches.

Lactoferrin Modulates Induction of Transcription Factor c-Fos in Neuronal Cultures

Lactoferrin (Lf) is a multifunctional protein from the transferrin family. Of particular interest is the ability of Lf to affect a wide range of neuronal processes by modulating the expression of genes involved in long-term neuroplasticity. The expression of the immediate early gene c-fos that is rapidly activated in response to external influences, and its product, transcription factor c-Fos, is widely used as a marker of long-term neuronal plasticity. The present study aims to examine the effect of human Lf on the induction of transcription factor c-Fos in the primary mouse neuronal cultures after stimulation and to determine the cellular localization of human Lf and its colocalization with induced c-Fos protein. Primary dissociated cultures of hippocampal cells were obtained from the brains of newborn C57BL/6 mice (P0-P1). On day 7 of culturing, human Lf was added to the medium. After 24 h (day 8 in culture), c-Fos protein was induced in cells by triple application of 50 mM KCl. c-Fos content was analyzed using the immunofluorescent method 2 h after stimulation. Stimulation promoted exogenous Lf translocation into the nuclei of cultured neuronal cells, which correlated with increased induction of transcription factor c-Fos and was accompanied by nuclear colocalization of these proteins. These results attest to the potential of Lf as a modulator of neuronal processes and open up new prospects in studying the mechanisms of the regulatory effects of lactoferrin on cell function.

Time to Kill and Time to Heal: The Multifaceted Role of Lactoferrin and Lactoferricin in Host Defense

Lactoferrin is an iron-binding glycoprotein present in most human exocrine fluids, particularly breast milk. Lactoferrin is also released from neutrophil granules, and its concentration increases rapidly at the site of inflammation. Immune cells of both the innate and the adaptive immune system express receptors for lactoferrin to modulate their functions in response to it. On the basis of these interactions, lactoferrin plays many roles in host defense, ranging from augmenting or calming inflammatory pathways to direct killing of pathogens. Complex biological activities of lactoferrin are determined by its ability to sequester iron and by its highly basic N-terminus, via which lactoferrin binds to a plethora of negatively charged surfaces of microorganisms and viruses, as well as to mammalian cells, both normal and cancerous. Proteolytic cleavage of lactoferrin in the digestive tract generates smaller peptides, such as N-terminally derived lactoferricin. Lactoferricin shares some of the properties of lactoferrin, but also exhibits unique characteristics and functions. In this review, we discuss the structure, functions, and potential therapeutic uses of lactoferrin, lactoferricin, and other lactoferrin-derived bioactive peptides in treating various infections and inflammatory conditions. Furthermore, we summarize clinical trials examining the effect of lactoferrin supplementation in disease treatment, with a special focus on its potential use in treating COVID-19.

Biomedical Applications of Lactoferrin on the Ocular Surface

Lactoferrin (LF) is a first-line defense protein with a pleiotropic functional pattern that includes anti-inflammatory, immunomodulatory, antiviral, antibacterial, and antitumoral properties. Remarkably, this iron-binding glycoprotein promotes iron retention, restricting free radical production and avoiding oxidative damage and inflammation. On the ocular surface, LF is released from corneal epithelial cells and lacrimal glands, representing a significant percentage of the total tear fluid proteins. Due to its multifunctionality, the availability of LF may be limited in several ocular disorders. Consequently, to reinforce the action of this highly beneficial glycoprotein on the ocular surface, LF has been proposed for the treatment of different conditions such as dry eye, keratoconus, conjunctivitis, and viral or bacterial ocular infections, among others. In this review, we outline the structure and the biological functions of LF, its relevant role at the ocular surface, its implication in LF-related ocular surface disorders, and its potential for biomedical applications.

Implication of extrinsic and intrinsic apoptotic pathways in the targeted therapy of hepatocellular carcinoma using aptamer-labeled viramidine nanoparticles

Hepatocellular carcinoma (HCC) is a global health problem with regional differences in epidemiological statistics. Co-assembling the drug nanoparticles and targeting moieties could improve the therapeutic delivery of anti-cancer drugs. In this attempt, we tracked the extrinsic and intrinsic apoptotic pathways in HCC cells using viramidine (VRM)-loaded aptamer (APT) nanoparticles. In these NPs, both APT and VRM act as targeted ligands/drugs to HCC cells. The NPs were characterized using TEM, ESI–MS, FTIR, and ¹H NMR. The results showed uniform particles with round and smooth shapes on the nano-scale. SRB-based cytotoxicity was performed and IC₅₀ values were measured for HCC versus normal cells upon the proposed treatments. The flow cytometry technique was applied to determine apoptosis, then confirmed using genetic and protein analyses. In addition, nitric oxide (NO) and its enzyme (iNOS) were analyzed to examine the effect of reactive nitrogen species (RNS) on apoptosis induction. The present findings indicated that Huh-7 cells were more sensitive to APT-VRM NPs than HepG2 cells, recording the lowest IC₅₀ values (11.23 ± 0.23 µM and 16.69 ± 1.12 µM), as well as the highest significant increase in the apoptotic cells (61.5% and 42%), respectively. Intriguingely, normal BHK-21 cells recorded undetectable IC₅₀ values in the applied NPs, confirming their targeted delivery ability. The genetic expression and protein levels of c-FLIP, Bcl-2, and TNF-α were down-regulated, while FADD, caspase 8, caspase 3, caspase 9, and Bax were up-regulated upon treatment with APT-VRM NPs. The prepared VRM NPs labeled with APT could significantly elevate NO via activation of iNOS. In conclusion, APT-VRM NPs bioconjugate interferes with HCC cells through NO-mediated extrinsic and intrinsic apoptosis.

Quantum Dot-Based Screening Identifies F3 Peptide and Reveals Cell Surface Nucleolin as a Therapeutic Target for Rhabdomyosarcoma

Active drug delivery by tumor-targeting peptides is a promising approach to improve existing therapies for rhabdomyosarcoma (RMS), by increasing the therapeutic effect and decreasing the systemic toxicity, e.g., by drug-loaded peptide-targeted nanoparticles. Here, we tested 20 different tumor-targeting peptides for their ability to bind to two RMS cell lines, Rh30 and RD, using quantum dots Streptavidin and biotin-peptides conjugates as a model for nanoparticles. Four peptides revealed a very strong binding to RMS cells: NCAM-1-targeting NTP peptide, nucleolin-targeting F3 peptide, and two Furin-targeting peptides, TmR and shTmR. F3 peptide showed the strongest binding to all RMS cell lines tested, low binding to normal control myoblasts and fibroblasts, and efficient internalization into RMS cells demonstrated by the cytoplasmic delivery of the Saporin toxin. The expression of the nucleophosphoprotein nucleolin, the target of F3, on the surface of RMS cell lines was validated by competition with the natural ligand lactoferrin, by colocalization with the nucleolin-binding aptamer AS1411, and by the marked sensitivity of RMS cell lines to the growth inhibitory nucleolin-binding N6L pseudopeptide. Taken together, our results indicate that nucleolin-targeting by F3 peptide represents a potential therapeutic approach for RMS.

New Properties of a Well-Known Antioxidant: Pleiotropic Effects of Human Lactoferrin in Mice Exposed to Gamma Irradiation in a Sublethal Dose

We studied the effects of human lactoferrin (hLf), a multifunctional protein from the transferrin family, on integral (survival, lifespan during the experiment, body weight, behavior, subfractional compositions of blood serum) and systemic (hemoglobin level, leukocyte number, differential leukocyte count, histological structure of the liver and spleen) parameters of the body in mice after acute gamma irradiation in a sublethal dose. The experiments were performed on male C57BL/6 mice. The mice in the experimental groups were exposed to whole-body gamma radiation in a dose of 7.5 Gy from a ⁶⁰Co source. Immediately after irradiation and 24 h after it, some animals received an intraperitoneal injection of hLf (4 mg/mouse). Single or repeated administration of hLf had a positive pleiotropic effect on irradiated animals: animal survival increased from 28% to 78%, and the mean life expectancy during the experiment (30 days) increased from 16 to 26 days. A compensatory effect of hLf on radiation-induced body weight loss, changes in homeostasis parameters, and a protective effect on the structural organization of the spleen were demonstrated. These data indicate that Lf has potential as a means of early therapy after radiation exposure.

Cell surface nucleolin is a novel ADAMTS5 receptor mediating endothelial cell apoptosis

A Disintegrin and Metalloproteinase with ThromboSpondin motif (ADAMTS) 5 functions as an anti-angiogenic and anti-cancer protein independent of its metalloproteinase activity. Both full-length ADAMTS5 and TS5-p45, the autocatalytically cleaved C-terminal 45 kDa truncate of ADAMTS5, inhibits angiogenesis, and induces endothelial cell (EC) apoptosis. However, how ADAMTS5 triggers EC apoptosis remains unclear. This work shows that caspase-8 (Cas-8) and caspase-9 (Cas-9) are involved in TS5-p45-induced EC apoptosis. We identify cell surface nucleolin (NCL) as a novel high-affinity receptor for TS5-p45 in ECs, mediating TS5-p45's cell surface binding and pro-apoptotic function. We show that the central RNA-binding domain (RBD) of NCL is essential and sufficient for its binding to TS5-p45. Upon interacting with EC surface NCL, TS5-p45 is internalized through clathrin- and caveolin-dependent endocytosis and trafficked to the nucleus via late endosomes (LEs). We demonstrate that the nuclear trafficking of TS5-p45 is important for its pro-apoptotic activity as disruption of LE membrane integrity with an endosomolytic peptide suppressed both nuclear trafficking and pro-apoptotic activity of TS5-p45. Through cell surface biotinylation, we revealed that cell surface NCL shuttles extracellular TS5-p45 to the nucleus to mediate apoptosis. Furthermore, blocking the importin α1/ß1 receptor hindered the nuclear trafficking of TS5-p45, suggesting the involvement of the nuclear importing machinery for this nuclear translocation. RNA-seq identified many apoptosis-related genes that are differentially expressed at least two-fold in TS5-p45-treated ECs, with 10 of them qRT-PCR-validated and at least 5 of these genes potentially contributing to TS5-p45-NCL-induced apoptosis. Altogether, our work identifies NCL as a novel cell surface receptor for ADAMTS5 and demonstrates the critical role of NCL-mediated internalization and nuclear trafficking for ADAMTS5-induced EC apoptosis. These findings reveal novel mechanistic insights of the secreted metalloproteinase ADAMTS5 in angiogenesis inhibition.

Therapeutic Potential of Nutraceuticals and Dietary Supplements in the Prevention of Viral Diseases: A Review

Nowadays, despite enormous scientific advances, viral diseases remain the leading cause of morbidity worldwide, and their potential to spread is escalating, eventually turning into pandemics. Nutrition can play a major role in supporting the immune system of the body and for the optimal functioning of the cells of the immune system. A healthy diet encompassing vitamins, multi-nutrient supplements, functional foods, nutraceuticals, and probiotics can play a pivotal role in combating several viral invasions in addition to strengthening the immune system. This review provides comprehensive information on diet-based scientific recommendations, evidence, and worldwide case studies in light of the current pandemic and also with a particular focus on virus-induced respiratory tract infections. After reviewing the immune potential of nutraceuticals based on the lab studies and on human studies, it was concluded that bioactive compounds such as nutraceuticals, vitamins, and functional foods (honey, berries, etc.) with proven antiviral efficacy, in addition to pharmaceutical medication or alone as dietary supplements, can prove instrumental in treating a range of virus-induced infections in addition to strengthening the immune system. Milk proteins and peptides can also act as adjuvants for the design of more potent novel antiviral drugs.

Cell surface nucleolin as active bait for nanomedicine in cancer therapy: a promising option

Conventional chemotherapy used against cancer is mostly limited due to their non-targeted nature, affecting normal tissue and causing undesirable toxic effects to the affected tissue. With the aim of improving these treatments both therapeutically and in terms of their safety, numerous studies are currently being carried out using nanoparticles (NPs) as a vector combining tumor targeting and carrying therapeutic tools. In this context, it appears that nucleolin, a molecule over-expressed on the surface of tumor cells, is an interesting therapeutic target. Several ligands, antagonists of nucleolin of various origins, such as AS1411, the F3 peptide and the multivalent pseudopeptide N6L have been developed and studied as therapeutic tools against cancer. Over the last ten years or so, numerous studies have been published demonstrating that these antagonists can be used as tumor targeting agents with NPs from various origins. Focusing on nucleolin ligands, the aim of this article is to review the literature recently published or under experimentation in our research team to evaluate the efficacy and future development of these tools as anti-tumor agents.

Cancer Stem Cells and Nucleolin as Drivers of Carcinogenesis

Cancer, one of the most mortal diseases worldwide, is characterized by the gain of specific features and cellular heterogeneity. Clonal evolution is an established theory to explain heterogeneity, but the discovery of cancer stem cells expanded the concept to include the hierarchical growth and plasticity of cancer cells. The activation of epithelial-to-mesenchymal transition and its molecular players are widely correlated with the presence of cancer stem cells in tumors. Moreover, the acquisition of certain oncological features may be partially attributed to alterations in the levels, location or function of nucleolin, a multifunctional protein involved in several cellular processes. This review aims at integrating the established hallmarks of cancer with the plasticity of cancer cells as an emerging hallmark; responsible for tumor heterogeneity; therapy resistance and relapse. The discussion will contextualize the involvement of nucleolin in the establishment of cancer hallmarks and its application as a marker protein for targeted anticancer therapies

Nucleolin acts as the receptor for C1QTNF4 and supports C1QTNF4-mediated innate immunity modulation

The C1q and TNF related 4 (C1QTNF4) protein is a structurally unique member of the C1QTNF family, a family of secreted proteins that have structural homology with both complement C1q and the tumor necrosis factor superfamily. C1QTNF4 has been linked to the autoimmune disease systemic lupus erythematosus through genetic studies; however, its role in immunity and inflammation remains poorly defined and a cell surface receptor of C1QTNF4 has yet to be identified. Here we report identification of nucleolin as a cell surface receptor of C1QTNF4 using mass spectrometric analysis. Additionally, we present evidence that the interaction between C1QTNF4 and nucleolin is mediated by the second C1q-like domain of C1QTNF4 and the C terminus of nucleolin. We show that monocytes and B cells are target cells of C1QTNF4 and observe extensive binding to dead cells. Imaging flow cytometry experiments in monocytes show that C1QTNF4 becomes actively internalized upon cell binding. Our results suggest that nucleolin may serve as a docking molecule for C1QTNF4 and act in a context-dependent manner through coreceptors. Taken together, these findings further our understanding of C1QTNF4's function in the healthy immune system and how dysfunction may contribute to the development of systemic lupus erythematosus.

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.

COVID-19 during Pregnancy and Postpartum

As the COVID-19 pandemic intensified the global health crisis, the containment of SARS-CoV-2 infection in pregnancies, and the inherent risk of vertical transmission of virus from mother-to-fetus (or neonate) poses a major concern. Most COVID-19-Pregnancy patients showed mild to moderate COVID-19 pneumonia with no pregnancy loss and no congenital transmission of the virus; however, an increase in hypoxia-induced preterm deliveries was apparent. Also, the breastmilk of several mothers with COVID-19 tested negative for the virus. Taken together, the natural barrier function during pregnancy and postpartum seems to deter the SARS-CoV-2 transmission from mother-to-child. This clinical observation warrants to explore the maternal-fetal interface and identify the innate defense factors for prevention and control of COVID-19-Pregnancy. Lactoferrin (LF) is a potent antiviral iron-binding protein present in the maternal-fetal interface. In concert with immune co-factors, maternal-LF modulates chemokine release and lymphocyte migration and amplify host defense during pregnancy. LF levels during pregnancy may resolve hypertension via down-regulation of ACE2; consequently, may limit the membrane receptor access to SARS-CoV-2 for cellular entry. Furthermore, an LF-derived peptide (LRPVAA) has been shown to block ACE receptor activity in vitro. LF may also reduce viral docking and entry into host cells and limit the early phase of COVID-19 infection. An in-depth understanding of LF and other soluble mammalian milk-derived innate antiviral factors may provide insights to reduce co-morbidities and vertical transmission of SARS-CoV-2 infection and may lead to the development of effective nutraceutical supplements.

Intracellular partners of fibroblast growth factors 1 and 2 - implications for functions

Fibroblast growth factors 1 and 2 (FGF1 and FGF2) are mainly considered as ligands of surface receptors through which they regulate a broad spectrum of biological processes. They are secreted in non-canonical way and, unlike other growth factors, they are able to translocate from the endosome to the cell interior. These unique features, as well as the role of the intracellular pool of FGF1 and FGF2, are far from being fully understood. An increasing number of reports address this problem, focusing on the intracellular interactions of FGF1 and 2. Here, we summarize the current state of knowledge of the FGF1 and FGF2 binding partners inside the cell and the possible role of these interactions. The partner proteins are grouped according to their function, including proteins involved in secretion, cell signaling, nucleocytoplasmic transport, binding and processing of nucleic acids, ATP binding, and cytoskeleton assembly. An in-depth analysis of the network of these binding partners could indicate novel, non-classical functions of FGF1 and FGF2 and uncover an additional level of a fine control of the well-known FGF-regulated cellular processes.

Viral Hepatitis and Iron Dysregulation: Molecular Pathways and the Role of Lactoferrin

The liver is a frontline immune site specifically designed to check and detect potential pathogens from the bloodstream to maintain a general state of immune hyporesponsiveness. One of the main functions of the liver is the regulation of iron homeostasis. The liver detects changes in systemic iron requirements and can regulate its concentration. Pathological states lead to the dysregulation of iron homeostasis which, in turn, can promote infectious and inflammatory processes. In this context, hepatic viruses deviate hepatocytes' iron metabolism in order to better replicate. Indeed, some viruses are able to alter the expression of iron-related proteins or exploit host receptors to enter inside host cells. Lactoferrin (Lf), a multifunctional iron-binding glycoprotein belonging to the innate immunity, is endowed with potent antiviral activity, mainly related to its ability to block viral entry into host cells by interacting with viral and/or cell surface receptors. Moreover, Lf can act as an iron scavenger by both direct iron-chelation or the modulation of the main iron-related proteins. In this review, the complex interplay between viral hepatitis, iron homeostasis, and inflammation as well as the role of Lf are outlined.

Antagonist of nucleolin, N6L, inhibits neovascularization in mouse models of retinopathies

Retinal vascular diseases (RVD) have been identified as a major cause of blindness worldwide. These pathologies, including the wet form of age-related macular degeneration, retinopathy of prematurity, and diabetic retinopathy are currently treated by intravitreal delivery of anti-vascular endothelial growth factor (VEGF) agents. However, repeated intravitreal injections can lead to ocular complications and resistance to these treatments. Thus, there is a need to find new targeted therapies. Nucleolin regulates the endothelial cell (EC) activation and angiogenesis. In previous studies, we designed a pseudopeptide, N6L, that binds the nucleolin and blocks the tumor angiogenesis. In this study, the effect of N6L was investigated in two experimental models of retinopathies including oxygen-induced retinopathy (OIR) and choroidal neovascularization (CNV). We found that in mouse OIR, intraperitoneal injection of N6L is delivered to activated ECs and induced a 50% reduction of pathological neovascularization. The anti-angiogenic effect of N6L has been tested in CNV model in which the systemic injection of N6L induced a 33% reduction of angiogenesis. This effect is comparable to those obtained with VEGF-trap, a standard of care drug for RVD. Interestingly, with preventive and curative treatments, neoangiogenesis is inhibited by 59%. Our results have potential interest in the development of new therapies targeting other molecules than VEGF for RVD.

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.

Engineering a Nanostructured Nucleolin-Binding Peptide for Intracellular Drug Delivery in Triple-Negative Breast Cancer Stem Cells

Five peptide ligands of four different cell surface receptors (nucleolin, CXCR1, CMKLR1, and CD44v6) have been evaluated as targeting moieties for triple-negative human breast cancers. Among them, the peptide F3, derived from phage display, promotes the fast and efficient internalization of a genetically fused green fluorescent protein (GFP) inside MDA-MB-231 cancer stem cells in a specific receptor-dependent fashion. The further engineering of this protein into the modular construct F3-RK-GFP-H6 and the subsequent construct F3-RK-PE24-H6 resulted in self-assembling polypeptides that organize as discrete and regular nanoparticles. These materials, 15-20 nm in size, show enhanced nucleolin-dependent cell penetrability. We show that the F3-RK-PE24-H6, based on the Pseudomonas aeruginosa exotoxin A (PE24) as a core functional domain, is highly cytotoxic over target cells. The combination of F3, the cationic peptide (RK)n, and the toxin domain PE24 in such unusual presentation appears as a promising approach to cell-targeted drug carriers in breast cancers and addresses selective drug delivery in otherwise difficult-to-treat triple-negative breast cancers.

Inhibition of miR-155 in MCF-7 breast cancer cell line by gold nanoparticles functionalized with antagomir and AS1411 aptamer

MicroRNAs are key factors for many biological functions. These regulatory molecules affect various gene networks and involve the subsequent signaling pathways. Therefore, disrupting the expression of these molecules is associated with multiple anomalies in the cells and body. One of the most important related abnormalities is the incidence of cancer. Thus, targeting microRNAs (miRNAs) is an effective approach for cancer gene therapy. Various factors are used for this purpose, including the antagomir nucleotide structure. There are some obstacles in the delivery of nucleotide therapeutics to the target cells, however, the use of nanoparticles could partly overcome these defeciencies. On the other hand, targeted delivery of antagomirs using aptamers, reduces nonspecific effects on nontarget cells. Considering the above, in this study, we designed and fabricated a nanocarrier composed of gold nanoparticles (GNPs), antagomir-155, and nucleolin specific aptamer for breast cancer study and therapy. Here, GNPs were synthesized using citrate reduction and were modified by polyA sequences, AS1411 aptamer, and antagomir-155. Attachment of molecules were confirmed using gel electrophoresis, atomic force microscopy imaging and electrochemical test. The specific entry of modified nanoparticles was investigated by fluorescence microscopy. The efficacy of modified nanoparticles was evaluated using a quantitative polymerase chain reaction (q-PCR) for miR-155 and its target gene. Efficient and specific delivery of AuNP-Apt-anti-miR-155 to target cells was confirmed in comparison with the control cell. The q-PCR analysis showed not only a significant decrease in mir-155 levels but also an elevated TP53INP1 mRNA, direct target of miR-155. The proposed structure inhibits proliferation and stimulates apoptosis by increasing the expression of TP53INP1. Our results suggest that AuNP-Apt-anti-miR-155 could be a promising nano constructor for breast cancer treatment.

Molecularly Engineering Triptolide with Aptamers for High Specificity and Cytotoxicity for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) lacks three important receptors, ER, PR, and HER2. It is more aggressive and more likely to relapse after treatment, thus has been identified as one of the most malignant breast cancer types. The development of efficient targeted TNBC therapy is an important research topic in TNBC treatment. We report the development of a new aptamer-drug conjugate (ApDC), AS1411-triptolide conjugate (ATC), as targeted therapy for the treatment of TNBC with high efficacy. The conjugate possesses excellent specificity and high cytotoxicity against the MDA-MB-231 cell line. The advantages of our newly invented ATC are further highlighted by its excellent in vivo anti-TNBC efficacy and negligible side effects toward healthy organs.

Nucleolin mediates the binding of cancer cells to L-selectin under conditions of lymphodynamic shear stress

Head and neck squamous cell carcinoma (HNSCC) cells bind to lymphocytes via L-selectin in a shear-dependent manner. This interaction takes place exclusively under low-shear stress conditions, such as those found within the lymph node parenchyma. This represents a novel functional role for L-selectin-selectin ligand interactions. Our previous work has characterized as-of-yet unidentified L-selectin ligands expressed by HNSCC cells that are specifically active under conditions of low shear stress consistent with lymph flow. Using an affinity purification approach, we now show that nucleolin expressed on the surface of HNSCC cells is an active ligand for L-selectin. Parallel plate chamber flow-based experiments and atomic force microscopy (AFM) experiments show that nucleolin is the main functional ligand under these low-force conditions. Furthermore, AFM shows a clear relationship between work of deadhesion and physiological loading rates. Our results reveal nucleolin as the first major ligand reported for L-selectin that operates under low-shear stress conditions.

Lactoferrin CpG Island Hypermethylation and Decoupling of mRNA and Protein Expression in the Early Stages of Prostate Carcinogenesis

Lactoferrin (LTF) is an iron-binding protein canonically known for its innate and adaptive immune functions. LTF may also act as a tumor suppressor with antiproliferative action. LTF is inactivated genetically or epigenetically in various cancers, and a CpG island spanning the transcriptional start site of LTF is hypermethylated in prostate cancer cell lines. We, therefore, hypothesized that LTF expression is silenced via CpG island hypermethylation in the early stages of prostate tumorigenesis carcinogenesis. Targeted methylation analysis was performed using a combination of methylated-DNA precipitation and methylation-sensitive restriction enzymes, and laser-capture microdissection followed by bisulfite sequencing on DNA isolated from prostate tissue samples, including both primary and metastatic disease. LTF mRNA in situ hybridization and LTF protein immunohistochemistry were also performed. We report that the LTF CpG island is frequently and densely methylated in high-grade prostatic intraepithelial neoplasia, primary prostate carcinoma, and metastases. We further report a decoupling of lactoferrin mRNA and protein expression, including in lesions where LTF mRNA has presumably been silenced via CpG island methylation. We conclude that LTF mRNA expression is silenced in prostate tumorigenesis via hypermethylation, supporting a role for LTF as a prostate cancer tumor suppressor gene. Likewise, the frequency at which the LTF CpG island is methylated across samples suggests it is an important and conserved step in prostate cancer initiation.

Nucleolin-based targeting strategies for cancer therapy: from targeted drug delivery to cytotoxic ligands

Cancer is currently the second leading cause of death worldwide and current therapeutic approaches remain ineffective in several cases. Therefore, there is a need to develop more efficacious therapeutic agents, especially for subtypes of cancer lacking targeted therapies. Limited drug penetration into tumors impairs the efficacy of therapies targeting cancer cells. One of the strategies to overcome this problem is targeting the more accessible tumor vasculature via molecules such as nucleolin, which is expressed at the surface of cancer and angiogenic endothelial cells, thus enabling a dual cellular targeting strategy. In this review, we present and discuss nucleolin-based targeting strategies that have been developed for cancer therapy, with a special focus on recent antibody-based approaches.

Lactoferrin translocates to the nucleus of bovine rectal epithelial cells in the presence of Escherichia coli O157:H7

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a foodborne pathogen which causes illness in humans. Ruminants are the main reservoirs and EHEC predominantly colonizes the epithelium of the recto-anal junction of cattle. Immunosuppression by EHEC promotes re-infection of cattle. However, bovine lactoferrin (bLF) apparently can overrule the immunosuppression by inducing EHEC-specific IgA responses at the mucosal site. The IgA responses are significantly correlated with reduced EHEC shedding and the absence of colonization at the rectal mucosa following re-infection. Therefore, to examine the interaction between bLF and bovine rectal epithelial cells, we first developed a method to establish a primary cell culture of epithelial cells of the rectum of cattle. Furthermore, we used LC–MS/MS to demonstrate the presence of secreted lactoferrin in bovine milk and the absence of a “delta” isoform which is known to translocate to the nucleus of cells. Nevertheless, lactoferrin derived from bovine milk was internalized by rectal epithelial cells and translocated to the nuclei. Moreover, nuclear translocation of bLF was significantly enhanced when the epithelial cells were inoculated with EHEC, as demonstrated by confocal fluorescence microscopy and confirmed by Raman microscopy and 3D imaging.

Lactoferrin in Aseptic and Septic Inflammation

Lactoferrin (Lf), a cationic glycoprotein able to chelate two ferric irons per molecule, is synthesized by exocrine glands and neutrophils. Since the first anti-microbial function attributed to Lf, several activities have been discovered, including the relevant anti-inflammatory one, especially associated to the down-regulation of pro-inflammatory cytokines, as IL-6. As high levels of IL-6 are involved in iron homeostasis disorders, Lf is emerging as a potent regulator of iron and inflammatory homeostasis. Here, the role of Lf against aseptic and septic inflammation has been reviewed. In particular, in the context of aseptic inflammation, as anemia of inflammation, preterm delivery, Alzheimer’s disease and type 2 diabetes, Lf administration reduces local and/or systemic inflammation. Moreover, Lf oral administration, by decreasing serum IL-6, reverts iron homeostasis disorders. Regarding septic inflammation occurring in Chlamydia trachomatis infection, cystic fibrosis and inflammatory bowel disease, Lf, besides the anti-inflammatory activity, exerts a significant activity against bacterial adhesion, invasion and colonization. Lastly, a critical analysis of literature in vitro data reporting contradictory results on the Lf role in inflammatory processes, ranging from pro- to anti-inflammatory activity, highlighted that they depend on cell models, cell metabolic status, stimulatory or infecting agents as well as on Lf iron saturation degree, integrity and purity.

Nucleolin Overexpression Confers Increased Sensitivity to the Anti-Nucleolin Aptamer, AS1411

AS1411 is an antiproliferative DNA aptamer, which binds the ubiquitous protein, nucleolin. In this study, we show that constitutive overexpression of nucleolin confers increased sensitivity to the growth inhibitory effects of AS1411. HeLa cells overexpressing nucleolin have an increased growth rate and invasiveness relative to control cells. Nucleolin overexpressing cells demonstrate increased growth inhibition in response to the AS1411 treatment, which correlates with increased apoptosis and cell cycle arrest, when compared to non-transfected cells. AS1411 induces nucleolin expression at the RNA and protein level in HeLa cells, suggesting a feedback loop with important implications for the clinical use of AS1411.

Proteomic analysis of Tn-bearing glycoproteins from different stages of melanoma cells reveals new biomarkers

Cutaneous melanoma, the most aggressive form of skin cancer, responds poorly to conventional therapy. The appearance of Tn antigen-modified proteins in cancer is correlated with metastasis and poor prognoses. The Tn determinant has been recognized as a powerful diagnostic and therapeutic target, and as an object for the development of anti-tumor vaccine strategies. This study was designed to identify Tn-carrying proteins and reveal their influence on cutaneous melanoma progression. We used a lectin-based strategy to purify Tn antigen-enriched cellular glycoproteome, the LC-MS/MS method to identify isolated glycoproteins, and the DAVID bioinformatics tool to classify the identified proteins. We identified 146 different Tn-bearing glycoproteins, 88% of which are new. The Tn-glycoproteome was generally enriched in proteins involved in the control of ribosome biogenesis, CDR-mediated mRNA stabilization, cell-cell adhesion and extracellular vesicle formation. The differential expression patterns of Tn-modified proteins for cutaneous primary and metastatic melanoma cells supported nonmetastatic and metastatic cell phenotypes, respectively. To our knowledge, this study is the first large-scale proteomic analysis of Tn-bearing proteins in human melanoma cells. The identified Tn-modified proteins are related to the biological and molecular nature of cutaneous melanoma and may be valuable biomarkers and therapeutic targets.

Meeting the needs of breast cancer: A nucleolin's perspective

A major challenge in the management of breast cancer disease has been the development of metastases. Finding new molecular targets and the design of targeted therapeutic approaches to improve the overall survival and quality of life of these patients is, therefore, of great importance. Nucleolin, which is overexpressed in cancer cells and tumor-associated blood vessels, have been implicated in various processes supporting tumorigenesis and angiogenesis. Additionally, its overexpression has been demonstrated in a variety of human neoplasias as an unfavorable prognostic factor, associated with a high risk of relapse and low overall survival. Hence, nucleolin has emerged as a relevant target for therapeutic intervention in cancer malignancy, including breast cancer. This review focus on the contribution of nucleolin for cancer disease and on the development of therapeutic strategies targeting this protein. In this respect, it also provides a critical analysis about the potential and pitfalls of nanomedicine for cancer therapy.

Lactoferrin promotes murine C2C12 myoblast proliferation and differentiation and myotube hypertrophy

Lactoferrin (Lf) is a multifunctional glycoprotein, which promotes the proliferation of murine C2C12 myoblasts. In the present study, it was investigated how Lf promotes myoblast proliferation and whether Lf promotes myoblast differentiation or induces myotube hypertrophy. Lf promoted the proliferation of myoblasts in a dose-dependent manner. Myoblast proliferation increased on day 3 when myoblasts were cultured in the presence of Lf for three days and also when myoblasts were cultured in the presence of Lf for the first day and in the absence of Lf for the subsequent two days. In addition, Lf induced the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 in myoblasts. The mitogen-activated protein kinase kinase 1/2 inhibitor U0126 inhibited Lf-induced ERK1/2 phosphorylation and repressed Lf-promoted myoblast proliferation. C2C12 myoblasts, myotubes and skeletal muscle expressed low-density lipoprotein receptor-related protein (LRP)1 mRNA and Lf-promoted myoblast proliferation was attenuated by an LRP1 antagonist or LRP1 gene silencing. The knockdown of LRP1 repressed Lf-induced phosphorylation of ERK1/2. Furthermore, when myoblasts were induced to differentiate, Lf increased the expression of the myotube-specific structural protein, myosin heavy chain (MyHC) and promoted myotube formation. Knockdown of LRP1 repressed Lf-induced MyHC expression. Lf also increased myotube size following differentiation. These results indicate that Lf promotes myoblast proliferation and differentiation, at least partially through LRP1 and also stimulates myotube hypertrophy.

Nucleolin and ErbB2 inhibition reduces tumorigenicity of ErbB2-positive breast cancer

ErbB2, a member of the ErbB family of receptor tyrosine kinases, is an essential player in the cell's growth and proliferation signaling pathways. Amplification or overexpression of ErbB2 is observed in ∼30% of breast cancer patients, and often drives cellular transformation and cancer development. Recently, we have shown that ErbB2 interacts with the nuclear-cytoplasmic shuttling protein nucleolin, an interaction which enhances cell transformation in vitro, and increases mortality risk and disease progression rate in human breast cancer patients. Given these results, and since acquired resistance to anti-ErbB2-targeted therapy is a major obstacle in treatment of breast cancer, we have examined the therapeutic potential of targeting the ErbB2-nucleolin complex. The effect of the nucleolin-specific inhibitor GroA (AS1411) on ErbB2-positive breast cancer was tested in vivo, in a mouse xenograft model for breast cancer; as well as in vitro, alone and in combination with the ErbB2 kinase-inhibitor tyrphostin AG-825. Here, we show that in vivo treatment of ErbB2-positive breast tumor xenografts with GroA reduces tumor size and leads to decreased ErbB2-mediated signaling. Moreover, we found that co-treatment of breast cancer cell lines with GroA and the ErbB2 kinase-inhibitor tyrphostin AG-825 enhances the anti-cancer effects exerted by GroA alone in terms of cell viability, mortality, migration, and invasiveness. We, therefore, suggest a novel therapeutic approach, consisting of combined inhibition of ErbB2 and nucleolin, which has the potential to improve breast cancer treatment efficacy.

New perspectives of physiological and pathological functions of nucleolin (NCL)

Nucleolin (NCL) is a multifunctional protein that mainly localized in the nucleolus, it is also found in the nucleoplasm, cytoplasm and cell membrane. The three main structural domains allow the interaction of NCL with different proteins and RNA sequences. Moreover, specific post-translational modifications and its shuttling property also contribute to its multifunctionality. NCL has been demonstrated to be involved in a variety of aspects such as ribosome biogenesis, chromatin organization and stability, DNA and RNA metabolism, cytokinesis, cell proliferation, angiogenesis, apoptosis regulation, stress response and microRNA processing. NCL has been increasingly implicated in several pathological processes, especially in tumorigenesis and viral infection, which makes NCL a potential target for the development of anti-tumor and anti-viral strategies. In this review, we present an overview on the structure, localizations and various functions of NCL, and further describe how the multiple functions of NCL are correlated to its multiple cellular distributions.

Copine-7 binds to the cell surface receptor, nucleolin, and regulates ciliogenesis and Dspp expression during odontoblast differentiation

Tooth development is a progressive process regulated by interactions between epithelial and mesenchymal tissues. Our previous studies showed that copine-7 (Cpne7), a dental epithelium-derived protein, is a signalling molecule that is secreted by preameloblasts and regulates the differentiation of preodontoblasts into odontoblasts. However, the mechanisms involved in the translocation of Cpne7 from preameloblasts to preodontoblasts and the functions of Cpne7 during odontogenesis are poorly understood. Here, we showed that the internalization of Cpne7 was mediated primarily by caveolae. This process was initiated by Cpne7 binding to the cell surface protein, nucleolin. Treatment with recombinant Cpne7 protein (rCpne7) in human dental pulp cells (hDPCs) caused an increase in the number of ciliated cells. The expression level of cilium components, Ift88 and Kif3a, and Dspp were increased by rCpne7. Treatment with Ift88 siRNA in hDPCs and MDPC-23 cells significantly down-regulated the expression of Dspp, an odontoblastic differentiation marker gene. Furthermore, the treatment with nucleolin siRNA in MDPC-23 cells decreased the expression of Dmp1, Dspp, and cilium components. Our findings suggested that the binding of Cpne7 with its receptor, nucleolin, has an important function involving Cpne7 internalization into preodontoblasts and regulation of Dspp expression through ciliogenesis during odontoblast differentiation.

Inhibitory Effect of Bovine Lactoferrin on Catechol-O-Methyltransferase

Lactoferrin (LF) is a well-known multifunctional protein. In this study, we report the inhibitory potency of bovine LF (bLF) on catechol-O-methyltransferase (COMT), which catalyzes methylation of catechol substrates. We found that bLF binds to and inhibits COMT using its N-terminal region. An N-terminal peptide fragment obtained from bLF by trypsin digestion showed a higher inhibitory activity than intact bLF. A synthetic fragment of the bLF N-terminal residues 6-50, with two pairs of disulfide bonds, also showed higher inhibitory activity than intact bLF. Enzyme kinetic studies proved that bLF did not compete with S-adenosylmethionine (the methyl donor substrate) as well as methyl acceptor substrates such as dihydroxybenzoic acid, (-)-epicatechin, norepinephrine, or l-3,4-dihydroxyphenylalanine. The inhibitory potency of bLF decreased against a COMT preparation pretreated with dithiothreitol, suggesting that the oxidation status of COMT is relevant to interaction with bLF. We further confirmed that COMT activity in the cell extracts form Caco-2 and HepG2 cells was inhibited by bLF and by the synthesized fragment. Enzyme kinetic study indicated that bLF functions as a non-competitive inhibitor by binding to an allosteric surface of COMT.