Lactoferrin selectively triggers apoptosis in highly metastatic breast cancer cells through inhibition of plasmalemmal V-H+-ATPase

Nutraceutical and Health-Promoting Potential of Lactoferrin, an Iron-Binding Protein in Human and Animal: Current Knowledge

Lactoferrin is a natural cationic iron-binding glycoprotein of the transferrin family found in bovine milk and other exocrine secretions, including lacrimal fluid, saliva, and bile. Lactoferrin has been investigated for its numerous powerful influences, including anticancer, anti-inflammatory, anti-oxidant, anti-osteoporotic, antifungal, antibacterial, antiviral, immunomodulatory, hepatoprotective, and other beneficial health effects. Lactoferrin demonstrated several nutraceutical and pharmaceutical potentials and have a significant impact on improving the health of humans and animals. Lactoferrin plays a critical role in keeping the normal physiological homeostasis associated with the development of pathological disorders. The current review highlights the medicinal value, nutraceutical role, therapeutic application, and outstanding favorable health sides of lactoferrin, which would benefit from more exploration of this glycoprotein for the design of effective medicines, drugs, and pharmaceuticals for safeguarding different health issues in animals and humans.

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

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

Inhibition of DAMP actions in the tumoral microenvironment using lactoferrin-glycyrrhizin conjugate for glioblastoma therapy

BACKGROUND

High-mobility group box-1 (HMGB1) released from the tumor microenvironment plays a pivotal role in the tumor progression. HMGB1 serves as a damaged-associated molecular pattern (DAMP) that induces tumor angiogenesis and its development. Glycyrrhizin (GL) is an effective intracellular antagonist of tumor released HMGB1, but its pharmacokinetics (PK) and delivery to tumor site is deficient. To address this shortcoming, we developed lactoferrin-glycyrrhizin (Lf-GL) conjugate.

METHODS

Biomolecular interaction between Lf-GL and HMGB1 was evaluated by surface plasmon resonance (SPR) binding affinity assay. Inhibition of tumor angiogenesis and development by Lf-GL attenuating HMGB1 action in the tumor microenvironment was comprehensively evaluated through in vitro, ex vivo, and in vivo. Pharmacokinetic study and anti-tumor effects of Lf-GL were investigated in orthotopic glioblastoma mice model.

RESULTS

Lf-GL interacts with lactoferrin receptor (LfR) expressed on BBB and GBM, therefore, efficiently inhibits HMGB1 in both the cytoplasmic and extracellular regions of tumors. Regarding the tumor microenvironment, Lf-GL inhibits angiogenesis and tumor growth by blocking HMGB1 released from necrotic tumors and preventing recruitment of vascular endothelial cells. In addition, Lf-GL improved the PK properties of GL approximately tenfold in the GBM mouse model and reduced tumor growth by 32%. Concurrently, various biomarkers for tumor were radically diminished.

CONCLUSION

Collectively, our study demonstrates a close association between HMGB1 and tumor progression, suggesting Lf-GL as a potential strategy for coping with DAMP-related tumor microenvironment. HMGB1 is a tumor-promoting DAMP in the tumor microenvironment. The high binding capability of Lf-GL to HMGB1 inhibits tumor progression cascade such as tumor angiogenesis, development, and metastasis. Lf-GL targets GBM through interaction with LfR and allows to arrest HMGB1 released from the tumor microenvironment. Therefore, Lf-GL can be a GBM treatment by modulating HMGB1 activity.

Targeted Fisetin-Encapsulated β-Cyclodextrin Nanosponges for Breast Cancer

Fisetin (FS) is considered a safer phytomedicine alternative to conventional chemotherapeutics for breast cancer treatment. Despite its surpassing therapeutic potential, its clinical utility is hampered by its low systemic bioavailability. Accordingly, as far as we are aware, this is the first study to develop lactoferrin-coated FS-loaded β-cyclodextrin nanosponges (LF-FS-NS) for targeted FS delivery to breast cancer. NS formation through cross-linking of β-cyclodextrin by diphenyl carbonate was confirmed by FTIR and XRD. The selected LF-FS-NS showed good colloidal properties (size 52.7 ± 7.2 nm, PDI < 0.3, and ζ-potential 24 mV), high loading efficiency (96 ± 0.3%), and sustained drug release of 26 % after 24 h. Morphological examination using SEM revealed the mesoporous spherical structure of the prepared nanosponges with a pore diameter of ~30 nm, which was further confirmed by surface area measurement. Additionally, LF-FS-NS enhanced FS oral and IP bioavailability (2.5- and 3.2-fold, respectively) compared to FS suspension in rats. Antitumor efficacy evaluation in vitro on MDA-MB-231 cells and in vivo on an Ehrlich ascites mouse model demonstrated significantly higher activity and targetability of LF-FS-NS (30 mg/kg) compared to the free drug and uncoated formulation. Consequently, LF-FS-NS could be addressed as a promising formulation for the effective management of breast cancer.

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

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

Antitumor activity of bovine lactoferrin and its derived peptides against HepG2 liver cancer cells and Jurkat leukemia cells

Liver cancer and leukemia are the fourth and first causes, respectively, of cancer death in children and adults worldwide. Moreover, cancer treatments, although beneficial, remain expensive, invasive, toxic, and affect the patient's quality of life. Therefore, new anticancer agents are needed to improve existing agents. Because bovine lactoferrin (bLF) and its derived peptides have antitumor properties, we investigated the anticancer effect of bLF and LF peptides (LFcin17-30, LFampin265-284 and LFchimera) on liver cancer HepG2 cells and leukemia Jurkat cells. HepG2 and Jurkat cells were incubated with bLF and LF peptides. Cell proliferation was quantified by an MTT assay, and cell morphology and damage were visualized by light microscopy or by phalloidin-TRITC/DAPI staining. The discrimination between apoptosis/necrosis was performed by staining with Annexin V-Alexa Fluor 488 and propidium iodide, and the expression of genes related to apoptosis was analyzed in Jurkat cells. Finally, the synergistic interaction of bLF and LF peptides with cisplatin or etoposide was assessed by an MTT assay and the combination index. The present study demonstrated that bLF and LF peptides inhibited the viability of HepG2 and Jurkat cells, inducing damage to the cell monolayer of HepG2 cells and morphological changes in both cell lines. bLF, LFcin17-30, and LFampin265-284 triggered apoptosis in both cell lines, whereas LFchimera induced necrosis. These results suggested that bLF and LF peptides activate apoptosis by increasing the expression of genes of the intrinsic pathway. Additionally, bLF and LF peptides synergistically interacted with cisplatin and etoposide. In conclusion, bLF and LF peptides display anticancer activity against liver cancer and leukemia cells, representing an alternative or improvement in cancer treatment.

Lactoferrin perturbs intracellular trafficking, disrupts cholesterol-rich lipid rafts and inhibits glycolysis of highly metastatic cancer cells harbouring plasmalemmal V-ATPase

The milk-derived bovine lactoferrin (bLf) is an iron-binding glycoprotein with remarkable selective anticancer activity towards highly metastatic cancer cells displaying the proton pump V-ATPase at the plasma membrane. As studies aiming to dissect the bLf mechanisms of action are critical to improve its efficacy and boost its targeted clinical use, herein we sought to further uncover the molecular basis of bLf anticancer activity. We showed that bLf co-localizes with V-ATPase and cholesterol-rich lipid rafts at the plasma membrane of highly metastatic cancer cells. Our data also revealed that bLf perturbs cellular trafficking, induces intracellular accumulation of cholesterol and lipid rafts disruption, downregulates PI3K, and AKT or p-AKT and inhibits glycolysis of cancer cells harbouring V-ATPase at the plasma membrane lipid rafts. Altogether, our results can lay the foundation for future bLf-based targeted anticancer strategies as they unravel a novel cascade of molecular events that explains and further reinforces bLf selectivity for cancer cells displaying plasmalemmal V-ATPase.

2, 4, 5-Trideoxyhexopyranosides derivatives of diphyllin: Synthesis and anticancer activity

Diphyllin and its natural derivatives were identified as potent vacuolar H⁺ -ATPase (V-ATPase) inhibitors. In this study, twelve 2, 4, 5-trideoxyhexopyranosides derivatives of diphyllin were synthesized. Most of these compounds showed potent abilities to inhibit the growth of HT-29, MCF-7, HepG2 cancer cells with IC₅₀ values at submicromolar concentration. The compounds 5c3 and 5c4 showed the best inhibitory activity on breast cancer cell lines MCF-7 with IC₅₀ values of 0.09 and 0.10 μM. Compounds 5c3 and 5c4 showed similar V-ATPase inhibitory potency to diphyllin. Molecular docking showed that a hydrogen bond was found between the hydroxyl of 5c3 and SerA534 in the pocket of the V-ATPase receptor.

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.

A review on lactoferrin as a proton pump inhibitor

Lactoferrin (Lf) is a versatile natural milk-derived protein that exhibits multiple interesting biological activities. Since it is safe for human administration and currently manufactured using low cost and well-established large-scale processes, the Lf scientific community has been devoted at dissecting its mechanisms of action towards its more rational and efficient use for various applications. Emerging literature has identified proton pumping ATPases as molecular targets of Lf in different cellular models linked to distinct activities of this natural protein. Information on this subject has not been systematically analysed before, hence herein we review the current state of art on the effect of Lf on proton pumping ATPases. Though structurally different, we propose that Lf holds a proton pump inhibitor (PPI)-like activity based on the functional resemblance with the classical inhibitors of the stomach H⁺/K⁺-ATPase. The downstream events and outcomes of the PPI-like activity of Lf, as well as its impact for the development of improved Lf applications are also discussed.

Plasmalemmal V-ATPase as a Potential Biomarker for Lactoferrin-Based Anticancer Therapy

Lactoferrin (Lf) is a milk-derived protein with well-recognized potential as a therapeutic agent against a wide variety of cancers. This natural protein exhibits health-promoting effects and has several interesting features, including its selectivity towards cancer cells, good tolerability in humans, worldwide availability, and holding a generally recognized as safe (GRAS) status. To prompt the rational clinical application of this promising anticancer compound, previous works aimed to unveil the molecular mechanisms underlying its selective anticancer activity, where plasmalemmal V-ATPase was identified as an Lf target in cancer cells. V-ATPase is a proton pump critical for cellular homeostasis that migrates to the plasma membrane of highly metastatic cancer cells contributing to the acidity of the tumor microenvironment. Cancer cells were found to be susceptible to Lf only when this proton pump is present at the plasma membrane. Plasmalemmal V-ATPase can thus be an excellent biomarker for driving treatment decisions and forecasting clinical outcomes of Lf-based anticancer strategies. Future research endeavors should thus seek to validate this biomarker by thorough preclinical and clinical studies, as well as to develop effective methods for its detection under clinical settings.

Lactotransferrin Downregulation Serves as a Potential Predictor for the Therapeutic Effectiveness of mTOR Inhibitors in the Metastatic Clear Cell Renal Cell Carcinoma without PTEN Mutation

Approximately 30% of clear cell renal cell carcinoma (ccRCC) patients develop metastatic spread at the first diagnosis. Therefore, identifying a useful biomarker to predict ccRCC metastasis or therapeutic effectiveness in ccRCC patients is urgently needed. Previously, we demonstrated that lactotransferrin (LTF) downregulation enhanced the metastatic potential of ccRCC. Here, we show that LTF expression conversely associates with the mTORC1 activity as simulated by gene set enrichment analysis (GSEA). Moreover, Western blot analyses revealed that the LTF knockdown promoted, but the inclusion of recombinant human LTF protein suppressed, the phosphorylation of Akt/mTOR proteins in the detected ccRCC cells. Kaplan–Meier analyses demonstrated that the signature of combining an upregulated mTORC1 activity with a downregulated LTF expression referred to a worse overall and progression-free survival probabilities and associated with distant cancer metastasis in TCGA ccRCC patients. Furthermore, we found that the LTF-suppressed Akt/mTOR activation triggered an increased formation of autophagy in the highly metastatic ccRCC cells. The addition of autophagy inhibitor 3-methyadenine restored the LTF-suppressed cellular migration ability of highly metastatic ccRCC cells. Receiver operating characteristic (ROC) analyses showed that the expression of the LTF and MTORC1 gene set, not the autophagy gene set, could be the useful biomarkers to predict 5-year overall survival rate and cancer progression in ccRCC patients. Significantly, the signature of combining mTORC1 upregulation and LTF downregulation was shown as an independent prognostic factor in a multivariate analysis under the progression-free survival condition using the TCGA ccRCC database. Finally, the treatment with mTOR inhibitor rapamycin predominantly reduced the formation of autophagy and ultimately mitigated the cellular migration ability of ccRCC cells with LTF knockdown. Our findings suggest that LTF downregulation is a biomarker for guiding the use of mTOR inhibitors to combat metastatic ccRCC in the clinic.

A Novel Human Recombinant Lactoferrin Inhibits Lung Adenocarcinoma Cell Growth and Migration with No Cytotoxic Effect on Normal Human Epithelial Cells

Lung cancer remains the leading cause of cancer death worldwide. Despite the recent advances in cancer treatment, only a subset of patients responds to targeted and immune therapies, and many patients developing resistance after an initial response. Lactoferrin (Lf) is a natural glycoprotein with immunomodulatory and anticancer activities. We produced a novel recombinant human Lf (rhLf) that exhibits glycosylation profile compatible with the natural hLf for potential parenteral therapeutic applications. The aim of this study was to evaluate the anticancer effects of this novel rhLf in human lung adenocarcinoma cells and its mechanisms of action. The results showed a concentration-dependent inhibition of A549 cancer cell growth in response to rhLf. Treatment with 1 mg/ml of rhLf for 24 h and 72 h resulted in a significant inhibition of cancer cell growth by 32% and 25%, respectively. Moreover, rhLf increased fourfold the percentage of early and late apoptotic cells compared to the control. This effect was accompanied by increased levels of caspase-3 activity and cell cycle arrest at the S phase in rhLf-treated cancer cells. Furthermore, rhLf significantly attenuated A549 cell migration. Importantly, treatment of normal human bronchial epithelial (NHBE) cells with rhLf showed the cell viability and morphology comparable to the control. In contrast, chemotherapeutic etoposide induced cytotoxicity in NHBE cells and reduced the cell viability by 40%. These results demonstrate the selective anticancer effects of rhLf against lung adenocarcinoma cells without cytotoxicity on normal human cells. This study highlights a potential for clinical utility of this novel rhLf in patients with lung cancer.

Lactoferrin may inhibit the development of cancer via its immunostimulatory and immunomodulatory activities (Review)

Lactoferrin (Lf) is secreted by ectodermal tissue and has a structure similar to that of transferrin. Although Lf seems to be multifunctional, its main function is related to the natural defense system of mammals. The present review aims to highlight the major actions of Lf, including the regulation of cell growth, the inhibition of toxic compound formation, the removal of harmful free radicals and its important role in immune response regulation. Moreover, Lf has antibacterial, antiviral, antioxidant, anticancer and anti‑inflammatory activities. In addition, the use of Lf for functionalization of drug nanocarriers, with emphasis on tumor‑targeted drug delivery, is illustrated. Such effects serve as an important theoretical basis for its future development and application. In neurodegenerative diseases and the brains of elderly people, Lf expression is markedly upregulated. Lf may exert an anti‑inflammatory effect by inhibiting the formation of hydroxyl free radicals. Through its antioxidant properties, Lf can prevent DNA damage, thereby preventing tumor formation in the central nervous system. In addition, Lf specifically activates the p53 tumor suppressor gene.

Surface-Tailored Zein Nanoparticles: Strategies and Applications

Plant-derived proteins have emerged as leading candidates in several drug and food delivery applications in diverse pharmaceutical designs. Zein is considered one of the primary plant proteins obtained from maize, and is well known for its biocompatibility and safety in biomedical fields. The ability of zein to carry various pharmaceutically active substances (PAS) position it as a valuable contender for several in vitro and in vivo applications. The unique structure and possibility of surface covering with distinct coating shells or even surface chemical modifications have enabled zein utilization in active targeted and site-specific drug delivery. This work summarizes up-to-date studies on zein formulation technology based on its structural features. Additionally, the multiple applications of zein, including drug delivery, cellular imaging, and tissue engineering, are discussed with a focus on zein-based active targeted delivery systems and antigenic response to its potential in vivo applicability.

The milk-derived lactoferrin inhibits V-ATPase activity by targeting its V1 domain

Lactoferrin (Lf), a bioactive milk protein, exhibits strong anticancer and antifungal activities. The search for Lf targets and mechanisms of action is of utmost importance to enhance its effective applications. A common feature among Lf-treated cancer and fungal cells is the inhibition of a proton pump called V-ATPase. Lf-driven V-ATPase inhibition leads to cytosolic acidification, ultimately causing cell death of cancer and fungal cells. Given that a detailed elucidation of how Lf and V-ATPase interact is still missing, herein we aimed to fill this gap by employing a five-stage computational approach. Molecular dynamics simulations of both proteins were performed to obtain a robust sampling of their conformational landscape, followed by clustering, which allowed retrieving representative structures, to then perform protein-protein docking. Subsequently, molecular dynamics simulations of the docked complexes and free binding energy calculations were carried out to evaluate the dynamic binding process and build a final ranking based on the binding affinities. Detailed atomist analysis of the top ranked complexes clearly indicates that Lf binds to the V₁ cytosolic domain of V-ATPase. Particularly, our data suggest that Lf binds to the interfaces between A/B subunits, where the ATP hydrolysis occurs, thus inhibiting this process. The free energy decomposition analysis further identified key binding residues that will certainly aid in the rational design of follow-up experimental studies, hence bridging computational and experimental biochemistry.

Emerging insights on the role of V-ATPase in human diseases: Therapeutic challenges and opportunities

The control of the intracellular pH is vital for the survival of all organisms. Membrane transporters, both at the plasma and intracellular membranes, are key players in maintaining a finely tuned pH balance between intra- and extracellular spaces, and therefore in cellular homeostasis. V-ATPase is a housekeeping ATP-driven proton pump highly conserved among prokaryotes and eukaryotes. This proton pump, which exhibits a complex multisubunit structure based on cell type-specific isoforms, is essential for pH regulation and for a multitude of ubiquitous and specialized functions. Thus, it is not surprising that V-ATPase aberrant overexpression, mislocalization, and mutations in V-ATPase subunit-encoding genes have been associated with several human diseases. However, the ubiquitous expression of this transporter and the high toxicity driven by its off-target inhibition, renders V-ATPase-directed therapies very challenging and increases the need for selective strategies. Here we review emerging evidence linking V-ATPase and both inherited and acquired human diseases, explore the therapeutic challenges and opportunities envisaged from recent data, and advance future research avenues. We highlight the importance of V-ATPases with unique subunit isoform molecular signatures and disease-associated isoforms to design selective V-ATPase-directed therapies. We also discuss the rational design of drug development pipelines and cutting-edge methodological approaches toward V-ATPase-centered drug discovery. Diseases like cancer, osteoporosis, and even fungal infections can benefit from V-ATPase-directed therapies.

Lactoferrin perturbs lipid rafts and requires integrity of Pma1p-lipid rafts association to exert its antifungal activity against Saccharomyces cerevisiae

Lactoferrin (Lf) is a bioactive milk-derived protein with remarkable wide-spectrum antifungal activity. To deepen our understanding of the molecular mechanisms underlying Lf cytotoxicity, the role of plasma membrane ergosterol- and sphingolipid-rich lipid rafts and their association with the proton pump Pma1p was explored. Pma1p was previously identified as a Lf-binding protein. Results showed that bovine Lf (bLf) perturbs ergosterol-rich lipid rafts organization by inducing intracellular accumulation of ergosterol. Using yeast mutant strains lacking lipid rafts-associated proteins or enzymes involved in the synthesis of ergosterol and sphingolipids, we found that perturbations in the composition of these membrane domains increase resistance to bLf-induced yeast cell death. Also, when Pma1p-lipid rafts association is compromised in the Pma1-10 mutant and in the absence of the Pma1p-binding protein Ast1p, the bLf killing activity is impaired. Altogether, results showed that the perturbation of lipid rafts and the inhibition of both Pma1p and V-ATPase activities mediate the antifungal activity of bLf. Since it is suggested that the combination of conventional antifungals with lipid rafts-disrupting compounds is a powerful antifungal approach, our data will help to pave the way for the use of bLf alone or in combination for the treatment/eradication of clinically and agronomically relevant yeast pathogens/fungi.

Lactoferrin: A Glycoprotein Involved in Immunomodulation, Anticancer, and Antimicrobial Processes

Lactoferrin is an iron binding glycoprotein with multiple roles in the body. Its participation in apoptotic processes in cancer cells, its ability to modulate various reactions of the immune system, and its activity against a broad spectrum of pathogenic microorganisms, including respiratory viruses, have made it a protein of broad interest in pharmaceutical and food research and industry. In this review, we have focused on describing the most important functions of lactoferrin and the possible mechanisms of action that lead to its function.

Bovine lactoferrin and lactoferrin peptides affect endometrial and cervical cancer cell lines

Cervical, uterine, and ovarian cancers are the most common malignancies of the female genital tract worldwide. Despite advances in prevention, early diagnosis, effective screening, and treatment programs, mortality remains high. Consequently, it is important to search for new treatments. The activity of bovine lactoferrin (bLF) and LF peptides against several types of cancer has been studied; however, only a few studies report the effect of bLF and LF peptides against cervical and endometrial cancers. In this study, we explored the effect of bLF as well as LF chimera and its constituent peptides LFcin17-30 and LFampin265-284 on the viability of cervical (HeLa, SiHa) and endometrial (KLE, HEC-1A) cancer cell lines. Cell proliferation was quantified with an MTT assay, cell morphological changes and damage were determined by Giemsa and phalloidin-TRITC and DAPI staining, and apoptotic and necrotic cells were identified by Alexa Fluor® 488 Annexin V and propidium iodide staining. Additionally, the effect of combinations of bLF and LF peptides with cisplatin was assessed. bLF and LF peptides inhibited the proliferation of uterine cancer cells and caused cellular morphological changes and damage to cell monolayers. bLF induced apoptosis, LFcin17-30 and LFampin265-284 induced apoptosis and necrosis, and LF chimera induced necrosis. Additionally, bLF and LF chimera showed an additive interaction with cisplatin against uterine cancer cells.

Recombinant human lactoferrin carrying humanized glycosylation exhibits antileukemia selective cytotoxicity, microfilament disruption, cell cycle arrest, and apoptosis activities

Lactoferrin has gained extensive attention due to its ample biological properties. In this study, recombinant human lactoferrin carrying humanized glycosylation (rhLf-h-glycan) expressed in the yeast Pichia pastoris SuperMan5, which is genetically glycoengineered to efficiently produce functional humanized glycoproteins inclosing (Man)₅(GlcNAc)₂ Asn-linked glycans, was analyzed, inspecting its potential toxicity against cancer cells. The live-cell differential nuclear staining assay was used to quantify the rhLf-h-glycan cytotoxicity, which was examined in four human cell lines: acute lymphoblastic leukemia (ALL) CCRF-CEM, T-cell lymphoblastic lymphoma SUP-T1, cervical adenocarcinoma HeLa, and as control, non-cancerous Hs27 cells. The defined CC₅₀ values of rhLf-h-glycan in CCRF-CEM, SUP-T1, HeLa, and Hs27 cells were 144.45 ± 4.44, 548.47 ± 64.41, 350 ± 14.82, and 3359.07 ± 164 µg/mL, respectively. The rhLf-h-glycan exhibited a favorable selective cytotoxicity index (SCI), preferentially killing cancer cells: 23.25 for CCRF-CEM, 9.59 for HeLa, and 6.12 for SUP-T1, as compared with Hs27 cells. Also, rhLf-h-glycan showed significant antiproliferative activity (P < 0.0001) at 24, 48, and 72 h of incubation on CCRF-CEM cells. Additionally, it was observed via fluorescent staining and confocal microscopy that rhLf-h-glycan elicited apoptosis-associated morphological changes, such as blebbing, nuclear fragmentation, chromatin condensation, and apoptotic bodies in ALL cells. Furthermore, rhLf-h-glycan-treated HeLa cells revealed shrinkage of the microfilament structures, generating a speckled/punctuated pattern and also caused PARP-1 cleavage, a hallmark of apoptosis. Moreover, in ALL cells, rhLf-h-glycan altered cell cycle progression inducing the G2/M phase arrest, and caused apoptotic DNA fragmentation. Overall, our findings revealed that rhLf-h-glycan has potential as an anticancer agent and therefore deserves further in vivo evaluation.

Lactoferrin, a multi-functional glycoprotein: Active therapeutic, drug nanocarrier & targeting ligand

Recent progress in protein-based nanomedicine, inspired by the success of Abraxane® albumin-paclitaxel nanoparticles, have resulted in novel therapeutics used for treatment of challenging diseases like cancer and viral infections. However, absence of specific drug targeting, poor pharmacokinetics, premature drug release, and off-target toxicity are still formidable challenges in the clinic. Therefore, alternative protein-based nanomedicines were developed to overcome those challenges. In this regard, lactoferrin (Lf), a glycoprotein of transferrin family, offers a promising biodegradable well tolerated material that could be exploited both as an active therapeutic and drug nanocarrier. This review highlights the major pharmacological actions of Lf including anti-cancer, antiviral, and immunomodulatory actions. Delivery technologies of Lf to improve its pries and enhance its efficacy were also reviewed. Moreover, different nano-engineering strategies used for fabrication of drug-loaded Lf nanocarriers were discussed. In addition, the use of Lf for functionalization of drug nanocarriers with emphasis on tumor-targeted drug delivery was illustrated. Besides its wide application in oncology nano-therapeutics, we discussed the recent advances of Lf-based nanocarriers as efficient platforms for delivery of anti-parkinsonian, anti-Alzheimer, anti-viral drugs, immunomodulatory and bone engineering applications.

The Recombinant Fragment of Human κ-Casein Induces Cell Death by Targeting the Proteins of Mitochondrial Import in Breast Cancer Cells

Breast cancer is still one of the most common cancers for women. Specified therapeutics are indispensable for optimal treatment. In previous studies, it has been shown that RL2, the recombinant fragment of human κ-Casein, induces cell death in breast cancer cells. However, the molecular mechanisms of RL2-induced cell death remain largely unknown. In this study, mechanisms of RL2-induced cell death in breast cancer cells were systematically investigated. In particular, we demonstrate that RL2 induces loss of mitochondrial membrane potential and cellular ATP loss followed by cell death in breast cancer cells. The mass spectrometry-based screen for RL2 interaction partners identified mitochondrial import protein TOM70 as a target of RL2, which was subsequently validated. Further to this, we show that RL2 is targeted to mitochondria after internalization into the cells, where it can also be found in the dimeric form. The importance of TOM70 and RL2 interaction in RL2-induced reduction in ATP levels was validated by siRNA-induced downregulation of TOM70, resulting in the partial rescue of ATP production. Taken together, this study demonstrates that RL2–TOM70 interaction plays a key role in RL2-mediated cell death and targeting this pathway may provide new therapeutic options for treating breast cancer.

Recombinant human lactoferrin induces apoptosis, disruption of F-actin structure and cell cycle arrest with selective cytotoxicity on human triple negative breast cancer cells

Breast cancer is the most frequently diagnosed cancer among women worldwide. Here, recombinant human lactoferrin (rhLf) expressed in Pichia pastoris was tested for its potential cytotoxic activity on a panel of six human breast cancer cell lines. The rhLf cytotoxic effect was determined via a live-cell HTS imaging assay. Also, confocal microscopy and flow cytometry protocols were employed to investigate the rhLf mode of action. The rhLf revealed an effective CC₅₀ of 91.4 and 109.46 µg/ml on non-metastatic and metastatic MDA-MB-231 cells, with favorable selective cytotoxicity index values, 11.68 and 13.99, respectively. Moreover, rhLf displayed satisfactory SCI values on four additional cell lines, MDA-MB-468, HCC70, MCF-7 and T-47D (1.55-3.34). Also, rhLf provoked plasma membrane blebbing, chromatin condensation and cell shrinkage in MDA-MB-231 cells, being all three apoptosis-related morphological changes. Also, rhLf was able to shrink the microfilaments, forming a punctuated cytoplasmic pattern in both the MDA-MB-231 and Hs-27 cells, as visualized in confocal photomicrographs. Moreover, performing flow cytometric analysis, rhLf provoked significant phosphatidylserine externalization, cell cycle arrest in the S phase and apoptosis-induced DNA fragmentation in MDA-MB-231 cells. Hence, rhLf possesses selective cytotoxicity on breast cancer cells. Also, rhLf caused apoptosis-associated morphologic changes, disruption of F-actin cytoskeleton organization, phosphatidylserine externalization, DNA fragmentation, and arrest of the cell cycle progression on triple-negative breast cancer MDA-MB-231 cells. Overall results suggest that rhLf is using the apoptosis pathway as its mechanism to inflict cell death. Findings warranty further evaluation of rhLf as a potential anti-breast cancer drug option.

Anti-neoplastic and immunomodulatory potency of co-treatment based on bovine lactoferrin and/or muramyl dipeptide in tumor-bearing mice

The current study investigates anti-neoplastic and immunomodulatory activities of co-treatment based on bovine lactoferrin (bLF) and/or muramyl dipeptide (MDP) with or without cisplatin (Cis) in tumor-bearing mice. In the present study, bLF (100 mg/kg; orally) and MDP (0.5 mg/kg; subcutaneously) was administered alone or together. MDP or bLF was co-treated with Cis (1 mg/kg; intraperitoneally) in mice-bearing Ehrlich solid carcinoma. Tumor size, tumor mass proliferation, apoptosis using immunohistochemistry, the alteration in spleen cell proliferation, phenotype using flow cytometry and white blood cells total and differential counts were detected. Treatment with Cis or (bLF and MDP) significantly reduced tumor size, upregulated the pro-apoptotic p53 expression and downregulated the anti-apoptotic Bcl-2 and proliferative marker PCNA expression compared to non-treated tumor-bearing animals. Moreover, co-treatment of MDP and Cis significantly potentiated the reduction of the tumor size, downregulated the Bcl-2 and PCNA expression and upregulated the p53 expression compared to Cis-treated animals. While bLF and Cis co-treatment positively controlled PCNA and p53 expression compared to tumor-bearing animals, it significantly potentiated the reduction of the tumor size and downregulated the Bcl-2 expression compared to Cis-treated animals. Co-treatment of (bLF and MDP), (bLF and Cis) or (MDP and Cis) increased the spleen cell proliferation and altered the immunological profile of the CD3⁺CD4⁺, CD3⁺CD8⁺, CD3⁺CD4⁺CD69⁺, CD3⁺CD8⁺CD69⁺ and CD11b⁺Ly6G⁺ cells to achieve better immune response against tumor. In conclusion, co-treatments based on bLF and/or MDP are promising therapies against cancer, through their potency to control proliferation, enhance apoptosis and improve the immune status against tumor cells.

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.

Elevated expression of the V-ATPase D2 subunit triggers increased energy metabolite levels in KrasG12D -driven cancer cells

Mutations of the Ras oncogene are frequently detected in human cancers. Among Ras-mediated tumorigenesis, Kras-driven cancers are the most dominant mutation types. Here, we investigated molecular markers related to the Kras mutation, which is involved in energy metabolism in Kras mutant-driven cancer. We first generated a knock-in Kras^G12D cell line as a model. The genotype and phenotype of the Kras ^G12D -driven cells were first confirmed. Dramatically elevated metabolite characterization was observed in Kras ^G12D -driven cells compared with wild-type cells. Analysis of mitochondrial metabolite-related genes showed that two of the 84 genes in Kras ^G12D -driven cells differed from control cells by at least twofold. The messenger RNA and protein levels of ATP6V0D2 were significantly upregulated in Kras ^G12D -driven cells. Knockdown of ATP6V0D2 expression inhibited motility and invasion but did not affect the proliferation of Kras ^G12D -driven cells. We further investigated ATP6V0D2 expression in tumor tissue microarrays. ATP6V0D2 overexpression was observed in most carcinoma tissues, such as melanoma, pancreas, and kidney. Thus, we suggest that ATP6V0D2, as one of the V-ATPase (vacuolar-type H ⁺ -ATPase) subunit isoforms, may be a potential therapeutic target for Kras mutation cancer.

Concepts, benefits and perspectives of functional dairy food products

The rising awareness of the consumers towards the health benefits of food has resulted in the development of the so-called functional foods. These added value products which refer to prevention and/or therapeutic effects of food beyond its nutritional value, are especially useful for health improvement and reduction of medical care costs. The combination between health and nutrition and its potential to improve the quality of life has become one of the key attention points of consumers who are aware of and are seeking nutritional solutions to their health concerns. Milk and dairy products have been used in human nutrition for thousands of years, providing important nutrients for the human body such as proteins, fats and calcium. It is now widely recognized that in addition to their basic nutritive role they also exert functional properties beneficial for human health, so the development of functional dairy products is one of the fastest growing areas in the dairy industry as well as one of the largest sectors in the global market of functional foods. This review provides a brief overview of the health benefits and the natural functionality of dairy products as well as the challenges together with the future perspectives of their application as delivery vehicles for beneficial compounds to the human body. Keywords: functional foods, milk, dairy products

Myrtenal-induced V-ATPase inhibition - A toxicity mechanism behind tumor cell death and suppressed migration and invasion in melanoma

BACKGROUND

Metastatic tumor cells have acidic extracellular pH and differential electrochemical H⁺ gradients generated across their cell membranes by V-type H⁺-ATPases. This study shows that inhibition of the V-ATPases by the plant-derived monoterpene Myrtenal results in tumor cell death and decreased metastatic dissemination in mice.

METHODS

The Myrtenal anticancer toxicity was evaluated in vitro using murine (B16F0 and B16F10) and human (SkMel-5) melanoma cell lines, and in in vivo mouse metastatic dissemination model. Proton flux and extracellular acidification were directly evaluated at the surface of living cells using a non-invasive selective ion electrode approach.

RESULTS

The inhibition of V-ATPases by 100 μM Myrtenal disrupted the electrochemical H⁺ gradient across the cell membranes, strongly induced cell death (4-5 fold), and decreased tumor cells migration and invasion in vitro. Myrtenal (15 mg/kg) also significantly reduced metastasis induced by B16F10 in vivo, further reinforcing that V-ATPase is a molecular target to halt the progression of cancers.

CONCLUSIONS

These data revealed the therapeutic potential of Myrtenal as inhibitor of melanoma progression proposing a mechanism of action by which once inhibited by this monoterpene the proton pumps fail to activate cancer-related differential electrochemical gradients and H⁺ fluxes across the tumor cell membranes, disrupting pH signatures inherent in tumor progression, resulting in reprogrammed cell death and metastasis inhibition.

GENERAL SIGNIFICANCE

The work represents a new mechanistic strategy for contention of melanoma, the most aggressive and deadly form of cutaneous neoplasm, and highlights Myrtenal, other related monoterpenes and derivatives as promising proton pump inhibitors with high chemotherapeutic potential.

Bovine Milk Lactoferrin Selectively Kills Highly Metastatic Prostate Cancer PC-3 and Osteosarcoma MG-63 Cells In Vitro

Prostate cancer and osteosarcoma are the second most common type of cancer affecting men and the fifth most common malignancy among adolescents, respectively. The use of non-toxic natural or natural-derived products has been one of the current strategies for cancer therapy, owing to the reduced risks of induced-chemoresistance development and the absence of secondary effects. In this perspective, lactoferrin (Lf), a natural protein derived from milk, emerges as a promising anticancer agent due to its well-recognized cytotoxicity and anti-metastatic activity. Here, we aimed to ascertain the potential activity of bovine Lf (bLf) against highly metastatic cancer cells. The bLf effect on prostate PC-3 and osteosarcoma MG-63 cell lines, both displaying plasmalemmal V-ATPase, was studied and compared with the breast cancer MDA-MB-231 and the non-tumorigenic BJ-5ta cell lines. Cell proliferation, cell death, intracellular pH, lysosomal acidification, and extracellular acidification rate were evaluated. Results show that bLf inhibits proliferation, induces apoptosis, intracellular acidification, and perturbs lysosomal acidification only in highly metastatic cancer cell lines. By contrast, BJ-5ta cells are insensitive to bLf. Overall, our results establish a common mechanism of action of bLf against highly metastatic cancer cells exhibiting plasmalemmal V-ATPase. This study opens promising perspectives for further research on the anticancer role of Lf, which ultimately will contribute to its safer and more rational application in the human therapy of these life-threatening cancers.

Low-dose-rate prostate brachytherapy: 4-8 week postimplant prostate-specific antigen a novel predictor of biochemical failure-free survival

PURPOSE

The purpose of this study was to determine the relationship between patient, disease, and treatment variables and biochemical failure-free survival (bFFS) following low-dose-rate prostate brachytherapy (LDR-BT).

METHODS AND MATERIALS

Data from 624 consecutive patients who received LDR-BT for localized prostate cancer between 2002 and 2012 at a single institution were collected for various patient, disease, and treatment characteristics including a 4-8 week postimplant PSA (4-8wkPSA). Subgroup analysis was stratified by risk category and treatment regimen. Analysis was performed using Kaplan-Meier survival curves, Cox proportional hazard ratios (HRs), and receiver-operator characteristic curves.

RESULTS

A total of 624 consecutive patients were included with followup time of 4.0 ± 3.1 years. Predictors of bFFS included PSA nadir and 4-8wkPSA (HR = 2.48, p = 0.000 and HR = 1.24, p = 0.000, respectively) for total population. Diabetes mellitus (p = 0.026), chronic obstructive pulmonary disease (p = 0.000), alcohol use (p = 0.024), and age (p = 0.002) were predictors for specific subgroups. Receiver-operator characteristic curves 4-8wkPSA were found to be significant (p = 0.036).

CONCLUSION

4-8wkPSA is a novel predictor of bFFS for patients receiving LDR-BT across several risk categories and treatment regimens with potential clinical utility as a prognostic indicator. Certain comorbidities and exposure histories also demonstrated significant relationships with bFFS including chronic obstructive pulmonary disease, diabetes mellitus, age, alcohol history, proton pump inhibitor use, PSA nadir, and PSA density.