Recombinant human lactoferrin-Fc fusion with an improved plasma half-life

Targeting Dual Immune Checkpoints PD-L1 and HLA-G by Trispecific T Cell Engager for Treating Heterogeneous Lung Cancer

Immunotherapy targeting immune checkpoints (ICPs), such as programmed death-ligand-1 (PD-L1), is used as a treatment option for advanced or metastatic non-small cell lung cancer (NSCLC). However, overall response rate to anti-PD-L1 treatment is limited due to antigen heterogeneity and the immune-suppressive tumor microenvironment. Human leukocyte antigen-G (HLA-G), an ICP as well as a neoexpressed tumor-associated antigen, is previously demonstrated to be a beneficial target in combination with anti-PD-L1. In this study, a nanobody-based trispecific T cell engager (Nb-TriTE) is developed, capable of simultaneously binding to T cells, macrophages, and cancer cells while redirecting T cells toward tumor cells expressing PD-L1- and/or HLA-G. Nb-TriTE shows broad spectrum anti-tumor effects in vitro by augmenting cytotoxicity mediated by human peripheral blood mononuclear cells (PBMCs). In a humanized immunodeficient murine NSCLC model, Nb-TriTE exhibits superior anti-cancer potency compared to monoclonal antibodies and bispecific T cell engagers. Nb-TriTE, at the dose with pharmacoactivity, does not induce additional enhancement of circulating cytokines secretion from PMBCs. Nb-TriTE effectively prolongs the survival of mice without obvious adverse events. In conclusion, this study introduces an innovative therapeutic approach to address the challenges of immunotherapy and the tumor microenvironment in NSCLC through utilizing the dual ICP-targeting Nb-TriTE.

Dose Range-Finding Toxicity Study in Rats With Recombinant Human Lactoferrin Produced in Komagataella phaffii

The oral toxicity of recombinant human lactoferrin (rhLF, Helaina rhLF, Effera™) produced in Komagataella phaffii was investigated in adult Sprague Dawley rats by once daily oral gavage for 14 consecutive days. The study used groups of 3-6 rats/sex/dose. The vehicle control group received sodium citrate buffer, and the test groups received daily doses of 200, 1000, and 2000 mg of rhLF in sodium citrate buffer per kg body weight. Bovine LF at 2000 mg/kg body weight per day was used as a comparative control. Clinical observations, body weight, hematology, clinical chemistry, iron parameters, immunophenotyping, and gross examination at necropsy were used as criteria for detecting the effects of treatment in all groups and to help select dose levels for future toxicology studies. Quantitative LF levels were also analyzed as an indication of bioavailability. Overall, administration of Helaina rhLF by once daily oral gavage for 14 days was well tolerated in rats at levels up to 2000 mg/kg/day, or 57 × Helaina's intended commercial use in adults, and indicating that a high dose of 2000 mg/kg/day is appropriate for future definitive toxicology studies.

Nanoparticular and other carriers to deliver lactoferrin for antimicrobial, antibiofilm and bone-regenerating effects: a review

Bone and joint infections are a rare but serious problem worldwide. Lactoferrin’s antimicrobial and antibiofilm activity coupled with its bone-regenerating effects may make it suitable for improving bone and joint infection treatment. However, free lactoferrin (LF) has highly variable oral bioavailability in humans due to potential for degradation in the stomach and small intestine. It also has a short half-life in blood plasma. Therefore, encapsulating LF in nanocarriers may slow degradation in the gastrointestinal tract and enhance LF absorption, stability, permeability and oral bioavailability. This review will summarize the literature on the encapsulation of LF into liposomes, solid lipid nanoparticles, nanostructured lipid carriers, polymeric micro and nanoparticles and hydroxyapatite nanocrystals. The fabrication, characterization, advantages, disadvantages and applications of each system will be discussed and compared.

A cytotoxic effect of human lactoferrin fusion with Fc domain of IgG

Lactoferrin (LTF) is a natural iron-binding protein with a potential for clinical utility in many human immune disorders, including cancer. A fusion of LTF with the Fc domain of IgG2 (FcLTF) was designed with inherent properties of an extended the half-life in circulation. Furthermore, the effects of LTF and FcLTF were assessed for influence on the activity of natural killer (NK) cells isolated from human peripheral blood, on the NK-92 cell line, and on human monocytes. The NK cytotoxic activity induced by LTF and FcLTF was determined against the human leukemia K562 cell line, and also for monocytes, by measuring TNFα and granzyme B production, and in an assay for Jurkat cell viability. Selected gene expression in NK-92 cells and monocytes, induced by LTF and FcLTF, was performed by Real Time PCR. No significant difference was observed in NK-92 cytotoxicity stimulated by LTF and FcLTF. The effects on NK cells isolated from the human peripheral blood were varied, possibly due to the immunoregulatory nature of LTF sensing the immune status of donors. Furthermore, only the FcLTF group strongly stimulated production of TNFα and granzyme B in isolated monocytes. In addition, only supernatants from the monocyte cultures treated with FcLTF decreased the viability of Jurkat cells. The ability of FcLTF to induce TNFα in monocytes was strongly inhibited by anti-CD32 and moderately inhibited by anti-CD14 antibody. Lastly, it was demonstrated that FcLTF, strongly induced expression of PI3K, with subsequent activation of AKT/mTOR signaling pathway. Overall, it was demonstrated that this novel fusion molecule may be a perferred choice for clinical utility than the wild type LTF.

Sustained Delivery of Lactoferrin Using Poloxamer Gels for Local Bone Regeneration in a Rat Calvarial Defect Model

Lactoferrin (LF) is a multifunctional milk glycoprotein that promotes bone regeneration. Local delivery of LF at the bone defect site is a promising approach for enhancement of bone regeneration, but efficient systems for sustained local delivery are still largely missing. The aim of this study was to investigate the potential of the poloxamers for sustained delivery of LF to enhance local bone regeneration. The developed LF/poloxamer formulations were liquid at room temperature (20 °C) transforming to a sustained releasing gel depot at body temperature (37 °C). In vitro release studies demonstrated an initial burst release (~50%), followed by slower release of LF for up to 72 h. Poloxamer, with and without LF, increased osteoblast viability at 72 h (p < 0.05) compared to control, and the immune response from THP-1 cells was mild when compared to the suture material. In rat calvarial defects, the LF/poloxamer group had lower bone volume than the controls (p = 0.0435). No difference was observed in tissue mineral density and lower bone defect coverage scores (p = 0.0267) at 12 weeks after surgery. In conclusion, LF/poloxamer formulations support cell viability and do not induce an unfavourable immune response; however, LF delivery via the current formulation of LF200/poloxamer gel did not demonstrate enhanced bone regeneration and was not compatible with the rat calvarial defect model.

Evaluation of Direct and Cell-Mediated Lactoferrin Gene Therapy for the Maxillofacial Area Abscesses in Rats

Resistance to antibacterial therapy requires the discovery of new methods for the treatment of infectious diseases. Lactoferrin (LTF) is a well-known naïve first-line defense protein. In the present study, we suggested the use of an adenoviral vector (Ad5) carrying the human gene encoding LTF for direct and cell-mediated gene therapy of maxillofacial area phlegmon in rats. Abscesses were developed by injection of the purulent peritoneal exudate in the molar region of the medial surface of the mandible. At 3-4 days after phlegmon maturation, all rats received ceftriaxone and afterward were subcutaneously injected around the phlegmon with: (1) Ad5 carrying reporter gfp gene encoding green fluorescent protein (Ad5-GFP control group), (2) Ad5 carrying LTF gene (Ad5-LTF group), (3) human umbilical cord blood mononuclear cells (UCBC) transduced with Ad5-GFP (UCBC + Ad5-GFP group), and (4) UCBC transduced with Ad5-LTF (UCBC + Ad5-LTF group). Control rats developed symptoms considered to be related to systemic inflammation and were euthanized at 4-5 days from the beginning of the treatment. Rats from therapeutic groups demonstrated wound healing and recovery from the fifth to seventh day based on the type of therapy. Histological investigation of cervical lymph nodes revealed purulent lymphadenitis in control rats and activated lymphatic tissue in rats from the UCBC + Ad5-LTF group. Our results propose that both approaches of LTF gene delivery are efficient for maxillofacial area phlegmon recovery in rats. However, earlier wound healing and better outcomes in cervical lymph node remodeling in the UCBC + Ad5-LTF group, as well as the lack of direct exposure of the viral vector to the organism, which may cause toxic and immunogenic effects, suggest the benefit of cell-mediated gene therapy.

Optimized lactoferrin as a highly promising treatment for intracerebral hemorrhage: Pre-clinical experience

Intracerebral hemorrhage (ICH) is the deadliest form of stroke for which there is no effective treatment, despite an endless number of pre-clinical studies and clinical trials. The obvious therapeutic target is the neutralization of toxic products of red blood cell (RBC) lysis that lead to cytotoxicity, inflammation, and oxidative damage. We used rigorous approaches and translationally relevant experimental ICH models to show that lactoferrin-(LTF)-based monotherapy is uniquely robust in reducing brain damage after ICH. Specifically, we designed, produced, and pharmacokinetically/toxicologically characterized an optimized LTF, a fusion of human LTF and the Fc domain of human IgG (FcLTF) that has a 5.8-fold longer half-life in the circulation than native LTF. Following dose-optimization studies, we showed that FcLTF reduces neurological injury caused by ICH in aged male/female mice, and in young male Sprague Dawley (SD) and spontaneously hypertensive rats (SHR). FcLTF showed a remarkably long 24-h therapeutic window. In tissue culture systems, FcLTF protected neurons from the toxic effects of RBCs and promoted microglia toward phagocytosis of RBCs and dead neurons, documenting its pleotropic effect. Our findings indicate that FcLTF is safe and effective in reducing ICH-induced damage in animal models used in this study.

The pain-relieving effects of lactoferrin on oxaliplatin-induced neuropathic pain

Oxaliplatin (OXL) therapy often causes side effects including chronic peripheral neuropathy. We investigated the pain-relieving effects of recombinant human lactoferrin (rhLf) as well as a long-acting IgG-Fc fused rhLf (rhLf-Fc) on OXL-induced neuropathic pain. We used the hLf in this study, because the homology between mouse Lf and hLf is higher than that of bovine Lf. In addition, rhLf-Fc is expected to enhance the analgesic effect due to the life extension effect in the body. We administered OXL (2 mg/kg, i.v.) to mice twice weekly for 4 weeks. Phosphate buffered saline (PBS), rhLf (100 mg/kg, i.p.) or rhLf-Fc (100 mg/kg, i.p.) was administered once a week from day 15 to 32. We also assessed the continuous infusion of same drugs (10 mg/kg/day) into the external jugular vein by using an osmotic pump. Both of rhLf and rhLf-Fc significantly reduced the hypersensitivity to mechanical stimulation when they were administered intraperitoneally. The continuous infusion of rhLf resulted in a more pronounced effect. Histopathological analysis of sciatic nerve showed that both rhLf and rhLf-Fc tended to reduce nerve fiber damage, but no significant difference was observed in nerve fiber cross-sectional area. Therefore, it was suggested that rhLf or rhLf-Fc injection could be an option for controlling neuropathic pain, which are side effects of OXL.

Albumin fusion at the N-terminus or C-terminus of human lactoferrin leads to improved pharmacokinetics and anti-proliferative effects on cancer cell lines

Human lactoferrin (hLF), a soluble factor of the innate immune system, exhibits various biological functions and therefore has potential as a therapeutic protein. However, the clinical applications of hLF are limited by its low stability in blood. We therefore attempted to resolve this by producing recombinant hLF fused to human serum albumin (HSA). Two HSA-fused hLFs with different fusion orientations (hLF-HSA and HSA-hLF) were produced in Chinese hamster ovary (CHO) DG44 cells. hLF-HSA revealed higher thermal stability, resistance to peptic degradation, and stability during the process of cellular uptake and release in an intestinal enterocyte model (Caco-2 cells) than HSA-hLF. The lower stability of HSA-hLF is presumably due to the steric hindrance imposed by HSA fusion to the N-terminus of hLF. Both HSA fusion proteins, especially HSA-hLF, displayed improved pharmacokinetic properties despite the lower protein stability of HSA-hLF. hLF-HSA and HSA-hLF exhibited approximately 3.3- and 20.7-fold longer half-lives (64.0 and 403.6 min), respectively, than holo-rhLF (19.5 min). Both HSA fusion proteins were found to exert enhanced growth inhibition effects on cancer cells in vitro, but not normal cells. Their enhanced growth inhibitory activities were considered to be due to the synergetic effects of hLF and HSA because hLF alone or HSA alone failed to exert such an effect. Altogether, Fusion of HSA to hLF yielded superior pharmacokinetics and anti-proliferative activities against cancer cells. HSA-fused hLF is a novel candidate for further application of hLF as biopharmaceuticals for intravenous administration.

Cellular Uptake and Release of Intact Lactoferrin and Its Derivatives in an Intestinal Enterocyte Model of Caco-2 Cells

An Intact form of lactoferrin (LF) is known to be absorbed from the small intestine and transported into the blood circulation. We reevaluated the cellular uptake and release of LF using an enterocyte model of human small intestinal cells derived from the Caco-2 cell line. In contrast to a previous report, we observed that intact bovine LF was taken up into seven and 21 d-cultured Caco-2 cells and successfully released back into the culture medium, even though the human intestinal LF receptor, intelectin-1, was not immunochemically detectable. Similar observations were made for human LF and its derivatives (the N-terminal half of LF designated N-lobe and Fc fusions). These observations regarding the uptake and release of intact LF in Caco-2 cells were consistent with in vivo observations. Therefore, we propose that the uptake and release of intact LF by Caco-2 cells should be assessed as a potential in vitro model of in vivo LF absorption in human intestines.

Soluble Human Intestinal Lactoferrin Receptor: Ca(2+)-Dependent Binding to Sepharose-Based Matrices

A soluble form of human intestinal lactoferrin receptor (shLFR) is identical to human intelectin-1 (hITLN-1), a galactofuranose-binding protein that acts as a host defense against invading pathogenic microorganisms. We found that recombinant shLFR, expressed in mammalian cells (CHO DG44, COS-1, and RK13), binds tightly to Sepharose 4 Fast Flow (FF)-based matrices in a Ca(2+)-dependent manner. This binding of shLFR to Sepharose 4 FF-based matrices was inhibited by excess D-galactose, but not by D-glucose, suggesting that shLFR recognizes repeating units of α-1,6-linked D-galactose in Sepharose 4 FF. Furthermore, shLFR could bind to both Sepharose 4B- and Sepharose 6B-based matrices that were not crosslinked in a similar manner as to Sepharose 4 FF-based matrices. Therefore, shLFR (hITLN-1) binds to Sepharose-based matrices in a Ca(2+)-dependent manner. This binding property is most likely related to the ability, as host defense lectins, to recognize sepharose (agarobiose)-like structures present on the surface of invading pathogenic microorganisms.

Potential Use of Biological Proteins for Liver Failure Therapy

Biological proteins have unlimited potential for use as pharmaceutical products due to their various biological activities, which include non-toxicity, biocompatibility, and biodegradability. Recent scientific advances allow for the development of novel innovative protein-based products that draw on the quality of their innate biological activities. Some of them hold promising potential for novel therapeutic agents/devices for addressing hepatic diseases such as hepatitis, fibrosis, and hepatocarcinomas. This review attempts to provide an overview of the development of protein-based products that take advantage of their biological activity for medication, and discusses possibilities for the therapeutic potential of protein-based products produced through different approaches to specifically target the liver (or hepatic cells: hepatocytes, hepatic stellate cells, liver sinusoidal endothelial cells, and Kupffer cells) in the treatment of hepatic diseases.