Protein-lipid complexes: molecular structure, current scenarios and mechanisms of cytotoxicity

Therapeutic efficacy of α-lactalbumin coated oleic acid based liposomes against colorectal carcinoma in Caco-2 cells and DMH-treated albino rats

Colorectal cancer (CRC) is a malignant tumor recognized as a major cause of morbidity and mortality throughout the world. Therefore, novel liposomes of oleic acid coated with camel α-lactalbumin (α-LA coated liposomes) were developed for their potential antitumor activity against CRC, both in vitro and in DMH-induced CRC-modeled animal. In vitro results indicated the high safety of α-LA coated liposomes towards normal human cells with potent antitumor activity against Caco-2 cells at an IC50 value of 57.01 ± 3.55 µM with selectivity index of 6.92 ± 0.48. This antitumor activity has been attributed to induction of the apoptotic mechanism, as demonstrated by nuclear condensation and arrest of Caco-2 cells in sub-G1 populations. α-LA coated liposomes also revealed a significant up-regulation of the p53 gene combined with a down-regulation of the Bcl2 gene. Moreover, in vivo results revealed that treatment of induced-CRC modeled animals with α-LA coated liposomes for six weeks markedly improved the CRC-disorders; this was achieved from the significant reduction in the values of AFP, CEA, CA19.9, TNF-α, IL-1β, MDA, and NO coupled with remarkable rise in SOD, GPx, GSH, CAT, and CD4+ levels. The histopathological findings asserted the therapeutic potential of α-LA coated liposomes in the treatment of CRC. Therefore, the present results proved the antitumor activity of α-LA coated liposomes against CRC through the restoration of impaired oxidative stress, improved immune response, and reduced inflammation.Communicated by Ramaswamy H. Sarma.

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.

Characterization of In Vivo Protein Complexes via Chemical Cross-Linking and Mass Spectrometry

Cells perform various functions by proteins via protein complexes. Characterization of protein complexes is critical to understanding their biological and clinical significance and has been one of the major efforts of functional proteomics. To date, most protein complexes are characterized by the in vitro system from protein extracts after the cells or tissues are lysed, and it has been challenging to determine which of these protein complexes are formed in intact cells. Herein, we report an approach to preserve protein complexes using in vivo cross-linking, followed by size exclusion chromatography and data-independent acquisition mass spectrometry. This approach enables the characterization of in vivo protein complexes from cells or tissues, which allows the determination of protein complexes in clinical research. More importantly, the described approach can identify protein complexes that are not detected by the in vitro system, which provide unique protein function information.

Lupin Protein Isolate Structure Diversity in Frozen-Cast Foams: Effects of Transglutaminases and Edible Fats

This study addresses an innovative approach to generate aerated foods with appealing texture through the utilization of lupin protein isolate (LPI) in combination with edible fats. We show the impact of transglutaminases (TGs; SB6 and commercial), glycerol (Gly), soy lecithin (Lec) and linoleic acid (LA) on the micro- and nanostructure of health promoting solid foods created from LPI and fats blends. 3-D tomographic images of LPI with TG revealed that SB6 contributed to an exceptional bubble spatial organization. The inclusion of Gly and Lec decreased protein polymerization and also induced the formation of a porous layered material. LA promoted protein polymerization and formation of homogeneous thick layers in the LPI matrix. Thus, the LPI is a promising protein resource which when in blend with additives is able to create diverse food structures. Much focus has been placed on the great foamability of LPI and here we show the resulting microstructure of LPI foams, and how these were improved with addition of TGs. New food applications for LPI can arise with the addition of food grade dispersant Lec and essential fatty-acid LA, by improved puffiness, and their contributing as replacer of chemical leavening additives in gluten-free products.

De novo expression and antibacterial potential of four lactoferricin peptides in cell-free protein synthesis system

For the first time, we produced four lactoferricin (LFcin) peptides by a cell-free (in vitro) method. These short antimicrobial peptides were expressed in an E. coli cell-free protein synthesis (CFPS) system and the bioactivity of the produced peptides was demonstrated. Additionally, we designed a novel synthetic consensus peptide (ConLFcin). The genes of bovine Lfcin (bLFcin), human Lfcin (hLFcin), camel Lfcin (cLFcin), and ConLFcin were cloned into pET101/D-TOPO vector then peptides were synthesized in vitro by E. coli CFPS system. The antibacterial activity of these synthesized peptides was evaluated against Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA). The four cell-free synthesized peptides showed significant antibacterial potency at minimum inhibitory concentration (MIC) values between 1.25 and 10 μg/mL. cLFcin and ConLFcin showed higher antibacterial effects than bLFcin and hLFcin. Thus, cell-free expression system is an ideal system for rapid expression of functionally active short bioactive peptides.

Comparative Analysis of Milk Fat Globular Membrane (MFGM) Proteome between Saudi Arabia Camelus dromedary Safra and Wadha Breeds

Camel milk is traditionally known to have medicinal properties and many potential health benefits. Natural milk contains many soluble proteins and nanoparticles, such as a milk fat globule membrane (MFGM), a three-layered membrane covering of milk fat globule mainly composed of proteins and lipids, which plays an important role in human health. MFGM proteins account for 1%-4% of total milk proteins, and their nutritive value and distribution depends on the different breeds. The differential composition of these membrane proteins among different camel breeds has not been explored. The current study, therefore, aimed to quantitatively analyze and compare the MFGM proteome between the milk produced by the two most common Saudi camel breeds, Camelus dromedarius: Safra and Wadha. Two-dimensional difference in gel electrophoresis (2D-DIGE) and mass spectrometry analysis revealed a total of 44 MFGM proteins that were identified with a significant difference in abundance (p ≤ 0.05; fold change ≥ 1.5) between the two breeds. Thirty-one proteins were up-regulated and 13 proteins were down-regulated in the Safra breed compared to the Wadha breed. The proteins identified with an increased abundance included α-lactalbumin, lactadherin, and annexin a8, whereas the down-regulated proteins included butyrophilin subfamily 1 member a1, lactotransferrin, and vinculin. The differentially abundant proteins were analyzed by the UNIPROT system and gene ontology (GO) to reveal their associations with known biological functions and pathways. Enzyme-linked immunosorbent assay (ELISA) confirmed the 2D-DIGE findings of butyrophilin (BTN) and α-lactalbumin (α-LA) levels obtained from Safra and Wadha breeds.