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Chetta KE, Forconi M, Newton DA, Wagner CL, Baatz JE. HAMLET in human milk is resistant to digestion and carries essential free long chain polyunsaturated fatty acids and oleic acid. Food Chem 2023; 427:136752. [PMID: 37392621 PMCID: PMC10527475 DOI: 10.1016/j.foodchem.2023.136752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/19/2023] [Accepted: 06/26/2023] [Indexed: 07/03/2023]
Abstract
The oleic acid/alpha-lactalbumin complex HAMLET (human alpha-lactalbumin made lethal to tumors) is cytotoxic to various cancerous cell lines and is assembled from alpha-lactalbumin (ALA) and free oleic acid (OA). HAMLET is also cytotoxic to normal immature intestinal cells. It remains unclear if HAMLET, experimentally assembled with OA and heat, can spontaneously assemble in frozen human milk over time. To approach this issue, we used a set of timed proteolytic experiments to evaluate the digestibility of HAMLET and native ALA. The purity of HAMLET in human milk was confirmed by ultra high performance liquid chromatography coupled to tandem mass spectrometry and western blot to resolve the ALA and OA components. Timed proteolytic experiments were used to identify HAMLET in whole milk samples. Structural characterization of HAMLET was performed by Fournier transformed infrared spectroscopy and indicated a transformation of secondary structure with increased alpha-helical character of ALA upon binding to OA.
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Affiliation(s)
- Katherine E Chetta
- Department of Pediatrics, C.P. Darby Children's Research Institute, Medical University of South Carolina, Charleston, SC, United States; Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Medical University of South Carolina, Shawn Jenkins Children's Hospital, 10 McClennan Banks Drive, MSC 915, Charleston, SC 29425, United States.
| | - Marcello Forconi
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC, United States
| | - Danforth A Newton
- Department of Pediatrics, C.P. Darby Children's Research Institute, Medical University of South Carolina, Charleston, SC, United States; Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Medical University of South Carolina, Shawn Jenkins Children's Hospital, 10 McClennan Banks Drive, MSC 915, Charleston, SC 29425, United States
| | - Carol L Wagner
- Department of Pediatrics, C.P. Darby Children's Research Institute, Medical University of South Carolina, Charleston, SC, United States; Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Medical University of South Carolina, Shawn Jenkins Children's Hospital, 10 McClennan Banks Drive, MSC 915, Charleston, SC 29425, United States
| | - John E Baatz
- Department of Pediatrics, C.P. Darby Children's Research Institute, Medical University of South Carolina, Charleston, SC, United States; Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Medical University of South Carolina, Shawn Jenkins Children's Hospital, 10 McClennan Banks Drive, MSC 915, Charleston, SC 29425, United States
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2
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Maulana RA, Fulyani F, Anjani G. Nanocarriers System for Vitamin D as Nutraceutical in Type 2 Diabetes: A Review. Open Access Maced J Med Sci 2022. [DOI: 10.3889/oamjms.2022.9507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Incidence of diabetes are common among population around the world. Diabetes may lead to other complication and increasing morbidity and mortality. Many ways have been done to treat and prevent the development of diabetes. In addition of conventional pharmacotherapy, therapeutic therapy shown good opportunity to maintain and improve diabetic conditions. Vitamin D3 is known as nutraceutical and has good opportunity to develop the medication of type 2 diabetes. In another way, vitamin D3 naturally easy to damage by environmental condition. To overcome this weakness, researcher around the world have developed the method for protecting unstable compound as vitamin D3 with encapsulation. Liprotide is one of the various materials which can be used for encapsulation. Combination of lipid and protein molecules is expected to be a carrier and protector of vitamin D3 in gastrointestinal system. Here we review the research advances of liprotide as nanocarriers and vitamin D3 as nutraceuticals to discuss in applied on type 2 diabetes.
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Chetta KE, Alcorn JL, Baatz JE, Wagner CL. Cytotoxic Lactalbumin-Oleic Acid Complexes in the Human Milk Diet of Preterm Infants. Nutrients 2021; 13:4336. [PMID: 34959888 PMCID: PMC8707396 DOI: 10.3390/nu13124336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/23/2021] [Accepted: 11/28/2021] [Indexed: 12/13/2022] Open
Abstract
Frozen storage is necessary to preserve expressed human milk for critically ill and very preterm infants. Milk pasteurization is essential for donor milk given to this special population. Due to these storage and processing conditions, subtle changes occur in milk nutrients. These changes may have clinical implications. Potentially, bioactive complexes of unknown significance could be found in human milk given to preterm infants. One such complex, a cytotoxic α-lactalbumin-oleic acid complex named "HAMLET," (Human Alpha-Lactalbumin Made Lethal to Tumor cells) is a folding variant of alpha-lactalbumin that is bound to oleic acid. This complex, isolated from human milk casein, has specific toxicity to both carcinogenic cell lines and immature non-transformed cells. Both HAMLET and free oleic acid trigger similar apoptotic mechanisms in tissue and stimulate inflammation via the NF-κB and MAPK p38 signaling pathways. This protein-lipid complex could potentially trigger various inflammatory pathways with unknown consequences, especially in immature intestinal tissues. The very preterm population is dependent on human milk as a medicinal and broadly bioactive nutriment. Therefore, HAMLET's possible presence and bioactive role in milk should be addressed in neonatal research. Through a pediatric lens, HAMLET's discovery, formation and bioactive benefits will be reviewed.
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Affiliation(s)
- Katherine E. Chetta
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Medical University of South Carolina, Shawn Jenkins Children’s Hospital, 10 McClennan Banks Drive, MSC 915, Charleston, SC 29425, USA; (J.E.B.); (C.L.W.)
| | - Joseph L. Alcorn
- Department of Pediatrics, Division of Neonatology and Pediatric Research Center, The University of Texas Health & Science Center at Houston, 6631 Fannin Street MSB 3.252, Houston, TX 77030, USA;
| | - John E. Baatz
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Medical University of South Carolina, Shawn Jenkins Children’s Hospital, 10 McClennan Banks Drive, MSC 915, Charleston, SC 29425, USA; (J.E.B.); (C.L.W.)
| | - Carol L. Wagner
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Medical University of South Carolina, Shawn Jenkins Children’s Hospital, 10 McClennan Banks Drive, MSC 915, Charleston, SC 29425, USA; (J.E.B.); (C.L.W.)
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Pedersen JN, Frislev HKS, Pedersen JS, Otzen D. Structures and mechanisms of formation of liprotides. Biochim Biophys Acta Proteins Proteom 2020; 1868:140505. [PMID: 32721568 DOI: 10.1016/j.bbapap.2020.140505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/16/2020] [Indexed: 12/11/2022]
Abstract
Many proteins form complexes called liprotides with oleic acid and other cis-fatty acids under conditions where the protein is partially unfolded. The complexes vary in structure depending on the ratio of protein and lipid, but the most common structural organization is the core-shell structure, in which a layer of dynamic, partially unfolded and extended proteins surrounds a micelle-like fatty acid core. This structure, first reported for α-lactalbumin together with OA, resembles complexes formed between proteins and anionic surfactants like SDS. Liprotides first rose to fame through their anti-carcinogenic properties which still remains promising for topical applications though not yet implemented in the clinic. In addition, liprotides show potential in drug delivery thanks to the ability of the micelle core to solubilize and stabilize hydrophobic compounds, though applications are challenged by their sensitivity to acidic pH and dynamic exchange of lipids which makes them easy prey for serum "hoovers" such as albumin. However, liprotides are also of fundamental interest as a generic "protein complex structure", demonstrating the many and varied structural consequences of protein-lipid interactions. Here we provide an overview of the different types of liprotide complexes, ranging from quasi-native complexes via core-shell structures to multi-layer structures, and discuss the many conditions under which they form. Given the many variable types of complexes that can form, rigorous biophysical analysis (stoichiometry, shape and structure of the complexes) remains crucial for a complete understanding of the mechanisms of action of this fascinating group of protein-lipid complexes both in vitro and in vivo.
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Affiliation(s)
- Jannik Nedergaard Pedersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Henriette Kristina Søster Frislev
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark; Novo Nordisk, Hallas Alle 1, DK-4400 Kalundborg, Denmark
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark; Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Daniel Otzen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark; Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark.
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El-Fakharany EM, Redwan EM. Protein-lipid complexes: molecular structure, current scenarios and mechanisms of cytotoxicity. RSC Adv 2019; 9:36890-36906. [PMID: 35539089 PMCID: PMC9075609 DOI: 10.1039/c9ra07127j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/21/2019] [Indexed: 02/04/2023] Open
Abstract
Some natural proteins can be complexed with oleic acid (OA) to form an active protein-lipid formulation that can induce tumor-selective apoptosis. The first explored protein was human milk α-lactalbumin (α-LA), called HAMLET when composed with OA in antitumor form. Several groups have prepared active protein-lipid complexes using a variety of approaches, all of which depend on target protein destabilization or direct OA-protein incubation to alter pH to acid or alkaline condition. In addition to performing vital roles in inflammatory processes and immune responses, fatty acids can disturb different metabolic pathways and cellular signals. Therefore, the tumoricidal action of these complexes is related to OA rather than the protein that keeps OA in solution and acts as a vehicle for transferring OA molecules to tumor cells. However, other studies have suggested that the antitumor efficacy of these complexes was exerted by both protein and OA together. The potential is not limited to the anti-tumor activity of protein-lipid complexes but extends to other functions such as bactericidal activity. The protein shell enhances the solubility and stability of the bound fatty acid. These protein-lipid complexes are promising candidates for fighting various cancer types and managing bacterial and viral infections.
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Affiliation(s)
- Esmail M El-Fakharany
- Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications (SRTA-City) New Borg EL-Arab 21934 Alexandria Egypt
| | - Elrashdy M Redwan
- Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications (SRTA-City) New Borg EL-Arab 21934 Alexandria Egypt
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University P. O. Box 80203 Jeddah Saudi Arabia
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Yarramala DS, Prakash P, Ranade DS, Doshi S, Kulkarni PP, Bhaumik P, Rao CP. Cytotoxicity of apo bovine α-lactalbumin complexed with La 3+ on cancer cells supported by its high resolution crystal structure. Sci Rep 2019; 9:1780. [PMID: 30741951 DOI: 10.1038/s41598-018-38024-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 12/11/2018] [Indexed: 11/08/2022] Open
Abstract
Cancer remains one of the biggest threats to human society. There are massive demands for compounds to selectively kill cancerous cells. Earlier studies have shown that bovine α -lactalbumin made lethal to tumor cells (BAMLET) becomes cytotoxic against cancer cells in complex with oleic acid {Hoque, M. et. al., PLoSOne8, e68390 (2013)}. In our study, we obtained bovine α-lactalbumin complexed with lanthanum ion (La3+-B-α-LA) and determined its high resolution crystal structure. The natural calcium binding site of bovine α-lactalbumin is replaced by lanthanum. The La3+ complex formation by B-α-apo-LA was also supported by various biophysical methods. Interestingly, our complex, La3+-B-α-LA exhibits much greater anticancer activity against breast cancer cells as compared to the reported BAMLET-oleic acid complex. This study shows that La3+-B-α-LA complex is preferentially more toxic to MCF-7 cells as compared to KB (oral cancer) and HeLa (cervical) cells, while almost non-toxic to the healthy cells that we studied. Our data indicates that the cytotoxicity of La3+-B-α-LA against cancer cells is through apoptotic path way. The higher anticancer activity of La3+-B-α-LA is attributable to the requisite structural changes induced in the protein by La3+ binding as supported by the crystal structure of the complex.
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7
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Park Y, Park Y, Jin S, Kim JW, Jung YM. Formation mechanism of BAMLET by 2D Raman correlation analysis. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.05.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Terracciano S, Lauro G, Russo A, Vaccaro MC, Vassallo A, De Marco M, Ranieri B, Rosati A, Turco MC, Riccio R, Bifulco G, Bruno I. Discovery and synthesis of the first selective BAG domain modulator of BAG3 as an attractive candidate for the development of a new class of chemotherapeutics. Chem Commun (Camb) 2018; 54:7613-7616. [DOI: 10.1039/c8cc03399d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first selective BAG3BD modulator has been discovered.
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Affiliation(s)
| | - Gianluigi Lauro
- Department of Pharmacy, University of Salerno
- 84084 Fisciano
- Italy
| | - Alessandra Russo
- Department of Pharmacy, University of Salerno
- 84084 Fisciano
- Italy
| | | | - Antonio Vassallo
- Department of Science, University of Basilicata
- 85100 Potenza
- Italy
| | - Margot De Marco
- DIPMED, University of Salerno
- 84081 Baronissi
- Italy
- BIOUNIVERSA S.r.l
- Montoro (AV)
| | | | - Alessandra Rosati
- DIPMED, University of Salerno
- 84081 Baronissi
- Italy
- BIOUNIVERSA S.r.l
- Montoro (AV)
| | | | - Raffaele Riccio
- Department of Pharmacy, University of Salerno
- 84084 Fisciano
- Italy
| | - Giuseppe Bifulco
- Department of Pharmacy, University of Salerno
- 84084 Fisciano
- Italy
| | - Ines Bruno
- Department of Pharmacy, University of Salerno
- 84084 Fisciano
- Italy
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Park Y, Kim Y, Park Y, Jin S, Hwang H, Jung YM. Formation mechanism of α-lactalabumin/oleic acid complex characterized by 2D correlation analysis. Spectrochim Acta A Mol Biomol Spectrosc 2017; 185:93-97. [PMID: 28549296 DOI: 10.1016/j.saa.2017.05.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/14/2017] [Indexed: 06/07/2023]
Abstract
Partially unfolded α-lactalbumin (ALA) forms a complex with oleic acid (OA) that exhibits cytotoxic activity. In this study, for the first time, the pH-induced formation mechanism for ALA/OA complexes with two different molar ratios was investigated at the molecular level. For a deeper understanding of the formation mechanism of the two different ALA/OA complexes with decreasing pH, principal component analysis (PCA) and two-dimensional (2D) correlation spectroscopy were used to examine the pH-dependent IR spectra of ALA/OA complexes. By tracking the secondary structural variations in the ALA/OA complexes with decreasing pH, we successfully elucidated the formation mechanism of the ALA/OA complexes at the molecular level. The results showed that the secondary structures of theses complexes exhibited the greatest change between pH4 and pH3.5 and that the components that mainly contributed to the pH-induced transition from the N-state to the A-state were dissimilar in the two different ALA/OA complexes.
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Affiliation(s)
- Yeonju Park
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Yeseul Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Yujeong Park
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Sila Jin
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Hoon Hwang
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Young Mee Jung
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea.
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Abstract
Alpha-lactalbumin (α-LA), a small milk calcium-binding globular protein, is known to possess noticeable anticancer activity, which is determined by the ability of this protein to form complexes with oleic acid (OA). To date, in addition to human and bovine α-LA, the ability to form such anti-tumor complexes with OA was described for goat and camel α-LA. Although the mechanisms of the anticancer activity of human and bovine α-LA are already well-studied, little is currently known about the anticancer action of this camel protein. The goal of this study was to fill this gap and to analyze the anticancer and pro-apoptotic activities of camel α-LA in its free form (α-cLA) and as an OA-containing complex (OA-α-cLA) using four human cancer cell lines, including Caco-2 colon cancer cells, PC-3 prostate cancer cells, HepG-2 hepatoma cells, and MCF-7 breast cancer cells as targets. The anti-tumor activities of OA-α-cLA and α-cLA were analyzed using MTT test, annexin/PI staining, cell cycle analysis, nuclear staining, and tyrosine kinase (TK) inhibition methods. We show here that the OA-α-cLA complex does not affect normal cells but has noticeable anti-cancer activity, especially against MCF-7 cells, thus boosting the anticancer activity of α-cLA and improving the selectivity of OA. The OA-α-cLA complex mediated cancer cell death via selective induction of apoptosis and cell-cycle arrest at lower IC50 than that of free α-cLA by more than two folds. However, OA induced apoptosis at higher extent than OA-α-cLA and α-cLA. OA also caused unselective apoptosis-dependent cell death in both normal and cancer cells to a similar degree. The apoptosis and cell-cycle arresting effect of OA-α-cLA may be attributed to the TK inhibition activity of OA. Therefore, OA-α-cLA serves as efficient anticancer complex with two functional components, α-cLA and OA, possessing different activities. This study declared the effectiveness of OA-α-cLA complex as a promising entity with anticancer activity, and these formulated OA-camel protein complexes constitute an auspicious approach for cancer remedy, particularly for breast cancer.
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Affiliation(s)
- Vladimir N Uversky
- a Department of Biological Sciences, Faculty of Sciences , King Abdulaziz University , Jeddah , Saudi Arabia.,b Institute for Biological Instrumentation of the Russian Academy of Sciences , Pushchino , Moscow region , Russia.,c Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute , Morsani College of Medicine, University of South Florida , Tampa , FL , USA
| | - Esmail M El-Fakharany
- d Therapeutic and Protective Proteins Laboratory, Protein Research Department, Medical Biotechnology Department, Genetic Engineering and Biotechnology Research Institute , City for Scientific Research and Technology Applications (SRTA-City) , Alexandria , Egypt
| | - Marwa M Abu-Serie
- e Medical Biotechnology Department , Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications (SRTA-City) , Alexandria , Egypt
| | - Hussein A Almehdar
- a Department of Biological Sciences, Faculty of Sciences , King Abdulaziz University , Jeddah , Saudi Arabia
| | - Elrashdy M Redwan
- a Department of Biological Sciences, Faculty of Sciences , King Abdulaziz University , Jeddah , Saudi Arabia.,d Therapeutic and Protective Proteins Laboratory, Protein Research Department, Medical Biotechnology Department, Genetic Engineering and Biotechnology Research Institute , City for Scientific Research and Technology Applications (SRTA-City) , Alexandria , Egypt
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Ho JC, Nadeem A, Svanborg C. HAMLET – A protein-lipid complex with broad tumoricidal activity. Biochem Biophys Res Commun 2017; 482:454-458. [DOI: 10.1016/j.bbrc.2016.10.092] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 12/22/2022]
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Chaudhuri A, Prasanna X, Agiru P, Chakraborty H, Rydström A, Ho JC, Svanborg C, Sengupta D, Chattopadhyay A. Protein-dependent Membrane Interaction of A Partially Disordered Protein Complex with Oleic Acid: Implications for Cancer Lipidomics. Sci Rep 2016; 6:35015. [PMID: 27731329 DOI: 10.1038/srep35015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/09/2016] [Indexed: 12/18/2022] Open
Abstract
Bovine α-lactalbumin (BLA) forms cytotoxic complexes with oleic acid (OA) that perturbs tumor cell membranes, but molecular determinants of these membrane-interactions remain poorly understood. Here, we aim to obtain molecular insights into the interaction of BLA/BLA-OA complex with model membranes. We characterized the folding state of BLA-OA complex using tryptophan fluorescence and resolved residue-specific interactions of BLA with OA using molecular dynamics simulation. We integrated membrane-binding data using a voltage-sensitive probe and molecular dynamics (MD) to demonstrate the preferential interaction of the BLA-OA complex with negatively charged membranes. We identified amino acid residues of BLA and BLA-OA complex as determinants of these membrane interactions using MD, functionally corroborated by uptake of the corresponding α-LA peptides across tumor cell membranes. The results suggest that the α-LA component of these cytotoxic complexes confers specificity for tumor cell membranes through protein interactions that are maintained even in the lipid complex, in the presence of OA.
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Birolo L, Sacchi S, Smaldone G, Molla G, Leo G, Caldinelli L, Pirone L, Eliometri P, Di Gaetano S, Orefice I, Pedone E, Pucci P, Pollegioni L. Regulating levels of the neuromodulatord-serine in human brain: structural insight into pLG72 andd-amino acid oxidase interaction. FEBS J 2016; 283:3353-70. [DOI: 10.1111/febs.13809] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/28/2016] [Accepted: 07/08/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Leila Birolo
- Dipartimento di Scienze Chimiche; Università degli Studi di Napoli Federico II; Napoli Italy
| | - Silvia Sacchi
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli studi dell'Insubria; Varese Italy
- Centro Interuniversitario di Ricerca in Biotecnologie Proteiche “The Protein Factory”; Politecnico di Milano and Università degli studi dell'Insubria; Milano Italy
| | | | - Gianluca Molla
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli studi dell'Insubria; Varese Italy
- Centro Interuniversitario di Ricerca in Biotecnologie Proteiche “The Protein Factory”; Politecnico di Milano and Università degli studi dell'Insubria; Milano Italy
| | - Gabriella Leo
- Dipartimento di Scienze Chimiche; Università degli Studi di Napoli Federico II; Napoli Italy
| | - Laura Caldinelli
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli studi dell'Insubria; Varese Italy
- Centro Interuniversitario di Ricerca in Biotecnologie Proteiche “The Protein Factory”; Politecnico di Milano and Università degli studi dell'Insubria; Milano Italy
| | - Luciano Pirone
- Italian Research National Council; Institute of Biostructures and Bioimaging; Napoli Italy
| | - Patrick Eliometri
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli studi dell'Insubria; Varese Italy
| | - Sonia Di Gaetano
- Italian Research National Council; Institute of Biostructures and Bioimaging; Napoli Italy
| | - Ida Orefice
- Dipartimento di Scienze Chimiche; Università degli Studi di Napoli Federico II; Napoli Italy
| | - Emilia Pedone
- Italian Research National Council; Institute of Biostructures and Bioimaging; Napoli Italy
| | - Piero Pucci
- Dipartimento di Scienze Chimiche; Università degli Studi di Napoli Federico II; Napoli Italy
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli studi dell'Insubria; Varese Italy
- Centro Interuniversitario di Ricerca in Biotecnologie Proteiche “The Protein Factory”; Politecnico di Milano and Università degli studi dell'Insubria; Milano Italy
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Roy SS, Mukherjee S, Ballard BR, Das SK. Protection Against Dimethylbenz[a] Anthracene-Induced Breast Cancer in Female Rats by α-Lactalbumin. Int J Cancer Oncol 2016; 3:1-6. [PMID: 27517093 PMCID: PMC4978184 DOI: 10.15436/2377-0902.16.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Consumption of α-lactalbumin as dietary protein offers a beneficial effect on breast cancer development. Breast cancer was developed by gavage administration of single dose of dimethylbenz(a)anthracene (DMBA) in female rats, maintained on AIN-76A diet with either 20% casein or α-lactalbumin (a component of whey protein). All tumors were detected by palpation. After approximately 130 days of DMBA administration, the animals were euthanized. There was a delay in the development of breast tumor in the α-lactalbumin group in comparison to the casein group. The number of tumors per rat was less in the α-lactalbumin group than that in the casein group at any time point up to 130 days after DMBA administration. Also the incidence of tumors and tumor volume was less in the α-lactalbumin group than those in the casein group. The casein group had a mixture of grade I, grade II and grade III tumors whereas the α-lactalbumin group had mostly grade I tumor. Furthermore, the proliferative index was significantly lower in the α-lactalbumin group than that in the casein group.
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Affiliation(s)
- Somdutta Sinha Roy
- Department of Biochemistry & Cancer Biology, Meharry Medical College, Nashville, TN, USA
| | - Shyamali Mukherjee
- Department of Professional Education, Neurosciences & Pharmacology, Nashville, TN, USA
| | - Billy R Ballard
- Department of Pathology, Meharry Medical College, Nashville, TN, USA
| | - Salil K Das
- Department of Biochemistry & Cancer Biology, Meharry Medical College, Nashville, TN, USA
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Woods KN, Pfeffer J. Using THz Spectroscopy, Evolutionary Network Analysis Methods, and MD Simulation to Map the Evolution of Allosteric Communication Pathways in c-Type Lysozymes. Mol Biol Evol 2016; 33:40-61. [PMID: 26337549 PMCID: PMC4693973 DOI: 10.1093/molbev/msv178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
It is now widely accepted that protein function is intimately tied with the navigation of energy landscapes. In this framework, a protein sequence is not described by a distinct structure but rather by an ensemble of conformations. And it is through this ensemble that evolution is able to modify a protein's function by altering its landscape. Hence, the evolution of protein functions involves selective pressures that adjust the sampling of the conformational states. In this work, we focus on elucidating the evolutionary pathway that shaped the function of individual proteins that make-up the mammalian c-type lysozyme subfamily. Using both experimental and computational methods, we map out specific intermolecular interactions that direct the sampling of conformational states and accordingly, also underlie shifts in the landscape that are directly connected with the formation of novel protein functions. By contrasting three representative proteins in the family we identify molecular mechanisms that are associated with the selectivity of enhanced antimicrobial properties and consequently, divergent protein function. Namely, we link the extent of localized fluctuations involving the loop separating helices A and B with shifts in the equilibrium of the ensemble of conformational states that mediate interdomain coupling and concurrently moderate substrate binding affinity. This work reveals unique insights into the molecular level mechanisms that promote the progression of interactions that connect the immune response to infection with the nutritional properties of lactation, while also providing a deeper understanding about how evolving energy landscapes may define present-day protein function.
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Kehoe JJ, Lišková K, Mok K, O'brien N, Kelly AL, Brodkorb A. Formation of cytotoxic α-lactalbumin / sodium oleate complexes: Concentration and temperature effects. Int Dairy J 2014; 38:65-73. [DOI: 10.1016/j.idairyj.2014.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Sullivan LM, Kehoe JJ, Barry L, Buckley MJ, Shanahan F, Mok KH, Brodkorb A. Gastric digestion of α-lactalbumin in adult human subjects using capsule endoscopy and nasogastric tube sampling. Br J Nutr 2014; 112:638-46. [PMID: 24967992 DOI: 10.1017/S0007114514001196] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In the present study, structural changes in the milk protein α-lactalbumin (α-LA) and its proteolysis were investigated for the potential formation of protein-fatty acid complexes during in vivo gastric digestion. Capsule endoscopy allowed visualisation of the digestion of the test drinks, with nasogastric tubes allowing sampling of the gastric contents. A total of ten healthy volunteers had nasogastric tubes inserted into the stomach and ingested test drinks containing 50 g/l of sucrose and 25 g/l of α-LA with and without 4 g/l of oleic acid (OA). The samples of gastric contents were collected for analysis at 3 min intervals. The results revealed a rapid decrease in the pH of the stomach of the subjects. The fasting pH of 2·31 (SD 1·19) increased to a pH maxima of pH 6·54 (SD 0·29) after ingestion, with a subsequent decrease to pH 2·22 (SD 1·91) after 21 min (n 8). Fluorescence spectroscopy and Fourier transform IR spectroscopy revealed partial protein unfolding, coinciding with the decrease in pH below the isoelectric point of α-LA. The activity of pepsin in the fasting state was found to be 39 (SD 12) units/ml of gastric juice. Rapid digestion of the protein occurred: after 15 min, no native protein was detected using SDS-PAGE; HPLC revealed the presence of small amounts of native protein after 24 min of gastric digestion. Mirocam® capsule endoscopy imaging and video clips (see the online supplementary material) revealed that gastric peristalsis resulted in a heterogeneous mixture during gastric digestion. Unfolding of α-LA was observed during gastric transit; however, there was no evidence of a cytotoxic complex being formed between α-LA and OA.
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Fang B, Zhang M, Tian M, Jiang L, Guo HY, Ren FZ. Bovine lactoferrin binds oleic acid to form an anti-tumor complex similar to HAMLET. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:535-43. [DOI: 10.1016/j.bbalip.2013.12.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 12/08/2013] [Accepted: 12/14/2013] [Indexed: 10/25/2022]
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Brück WM, Gibson GR, Brück TB. The effect of proteolysis on the induction of cell death by monomeric alpha-lactalbumin. Biochimie 2013; 97:138-43. [PMID: 24139905 DOI: 10.1016/j.biochi.2013.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/08/2013] [Indexed: 11/27/2022]
Abstract
α-Lactalbumin (α-la) is a major whey protein found in milk. Previous data suggested that α-la has antiproliferative effects in human adenocarcinoma cell lines such as Caco-2 and HT-29. However, the cell death inducing α-la was not a naturally occurring monomer but either a multimeric variant or an α-la:oleic acid complex (HAMLET/BAMLET). Proteolysis showed that both human and bovine α-la are susceptible to digestion. ELISA assays assessing cell death with the native undigested α-la fractions showed that undigested protein fractions did have a significant cell death effect on CaCo-2 cells. Bovine α-la was also more effective than human α-la. A reduction in activity corresponded with lower concentrations of the protein and partial digestion and fragmentation of the protein using trypsin and pepsin. This suggests that the tertiary structure is vital for the apoptotic effect.
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Affiliation(s)
- Wolfram M Brück
- CAMBio, Letterkenny Institute of Technology, Port Road, Letterkenny, Co. Donegal, Ireland.
| | - Glenn R Gibson
- Food Microbial Sciences Unit, School of Chemistry, Food and Pharmacy, University of Reading, Reading, UK
| | - Thomas B Brück
- Technische Universität München (TUM), Department of Chemistry, Division of Industrial Biocatalysis, Lichtenberg Str. 4, 85748 Garching bei München, Germany
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Hoque M, Dave S, Gupta P, Saleemuddin M. Oleic acid may be the key contributor in the BAMLET-induced erythrocyte hemolysis and tumoricidal action. PLoS One 2013; 8:e68390. [PMID: 24039698 PMCID: PMC3770648 DOI: 10.1371/journal.pone.0068390] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 06/03/2013] [Indexed: 12/19/2022] Open
Abstract
A chance discovery of the tumoricidal action of a human milk fraction led to the characterization of the active component as oleic acid complex of the α-lactalbumin, which was given the acronym HAMLET. We report in this study that the oleic acid complex of bovine α-lactalbumin (BAMLET) is hemolytic to human erythrocytes as well as to those derived from some other mammals. Indirect immunofluorescence analysis suggested binding of BAMLET to erythrocytes prior to induction of hemolysis. Free OA was hemolytic albeit at higher concentrations, while sodium oleate caused hemolysis at far lower concentrations. Amiloride and BaCl2 offered protection against BAMLET-induced hemolysis suggesting the involvement of a cation leak channel in the process. BAMLET coupled to CNBr-activated Sepharose was not only hemolytic but also tumoricidal to Jurkat and MCF-7 cells in culture. The Sepharose-linked preparation was however not toxic to non-cancerous peritoneal macrophages and primary adipocytes. The tumoricidal action was studied using the MTT-assay while apoptosis induction measured by the annexin V-propidium iodide assay. Repeated incubation of the immobilized BAMLET with erythrocytes depleted oleic acid and decreased the hemolytic activity of the complex. Incubation of MCF-7 and Jurkat cells with OA, soluble or immobilized BAMLET resulted in increase in the uptake of Lyso Tracker Red and Nile red by the cells. The data presented support the contention that oleic acid plays the key role, both in BAMLET-induced hemolysis and tumoricidal action.
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Affiliation(s)
- Mehboob Hoque
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Sandeep Dave
- Institute of Microbial Technology (CSIR), Chandigarh, India
| | - Pawan Gupta
- Institute of Microbial Technology (CSIR), Chandigarh, India
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Fontana A, Spolaore B, Polverino de Laureto P. The biological activities of protein/oleic acid complexes reside in the fatty acid. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2013; 1834:1125-43. [DOI: 10.1016/j.bbapap.2013.02.041] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/18/2013] [Accepted: 02/20/2013] [Indexed: 12/12/2022]
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Nakamura T, Aizawa T, Kariya R, Okada S, Demura M, Kawano K, Makabe K, Kuwajima K. Molecular mechanisms of the cytotoxicity of human α-lactalbumin made lethal to tumor cells (HAMLET) and other protein-oleic acid complexes. J Biol Chem 2013; 288:14408-14416. [PMID: 23580643 DOI: 10.1074/jbc.m112.437889] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Although HAMLET (human α-lactalbumin made lethal to tumor cells), a complex formed by human α-lactalbumin and oleic acid, has a unique apoptotic activity for the selective killing of tumor cells, the molecular mechanisms of expression of the HAMLET activity are not well understood. Therefore, we studied the molecular properties of HAMLET and its goat counterpart, GAMLET (goat α-lactalbumin made lethal to tumor cells), by pulse field gradient NMR and 920-MHz two-dimensional NMR techniques. We also examined the expression of HAMLET-like activities of complexes between oleic acid and other proteins that form a stable molten globule state. We observed that both HAMLET and GAMLET at pH 7.5 were heterogeneous, composed of the native protein, the monomeric molten globule-like state, and the oligomeric species. At pH 2.0 and 50 °C, HAMLET and GAMLET appeared in the monomeric state, and we identified the oleic acid-binding site in the complexes by two-dimensional NMR. Rather surprisingly, the binding site thus identified was markedly different between HAMLET and GAMLET. Furthermore, canine milk lysozyme, apo-myoglobin, and β2-microglobulin all formed the HAMLET-like complex with the anti-tumor activity, when the protein was treated with oleic acid under conditions in which their molten globule states were stable. From these results, we conclude that the protein portion of HAMLET, GAMLET, and the other HAMLET-like protein-oleic acid complexes is not the origin of their cytotoxicity to tumor cells and that the protein portion of these complexes plays a role in the delivery of cytotoxic oleic acid molecules into tumor cells across the cell membrane.
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Affiliation(s)
- Takashi Nakamura
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Tomoyasu Aizawa
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Ryusho Kariya
- Division of Hematopoiesis, Center for AIDS Research, Kumamoto University, 2-2-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Seiji Okada
- Division of Hematopoiesis, Center for AIDS Research, Kumamoto University, 2-2-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Makoto Demura
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Keiichi Kawano
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Koki Makabe
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (Sokendai), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Kunihiro Kuwajima
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (Sokendai), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
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Zhang YB, Gong JL, Xing TY, Zheng SP, Ding W. Autophagy protein p62/SQSTM1 is involved in HAMLET-induced cell death by modulating apotosis in U87MG cells. Cell Death Dis 2013; 4:e550. [PMID: 23519119 PMCID: PMC3615731 DOI: 10.1038/cddis.2013.77] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
HAMLET is a complex of oleic acids and decalcified α-lactalbumin that was discovered to selectively kill tumor cells both in vitro and in vivo. Autophagy is an important cellular process involved in drug-induced cell death of glioma cells. We treated U87MG human glioma cells with HAMLET and found that the cell viability was significantly decreased and accompanied with the activation of autophagy. Interestingly, we observed an increase in p62/SQSTM1, an important substrate of autophagosome enzymes, at the protein level upon HAMLET treatment for short periods. To better understand the functionality of autophagy and p62/SQSTM1 in HAMLET-induced cell death, we modulated the level of autophagy or p62/SQSTM1 with biochemical or genetic methods. The results showed that inhibition of autophagy aggravated HAMLET-induced cell death, whereas activation of authophagy attenuated this process. Meanwhile, we found that overexpression of wild-type p62/SQSTM1 was able to activate caspase-8, and then promote HAMLET-induced apoptosis, whereas knockdown of p62/SQSTM1 manifested the opposite effect. We further demonstrated that the function of p62/SQSTM1 following HAMLET treatment required its C-terminus UBA domain. Our results indicated that in addition to being a marker of autophagy activation in HAMLET-treated glioma cells, p62/SQSTM1 could also function as an important mediator for the activation of caspase-8-dependent cell death.
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Affiliation(s)
- Y-B Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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24
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Brinkmann CR, Thiel S, Otzen DE. Protein-fatty acid complexes: biochemistry, biophysics and function. FEBS J 2013; 280:1733-49. [DOI: 10.1111/febs.12204] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 11/29/2012] [Accepted: 02/12/2013] [Indexed: 02/01/2023]
Affiliation(s)
| | - Steffen Thiel
- Department of Biomedicine, Faculty of Health Sciences; Aarhus University; Denmark
| | - Daniel E. Otzen
- Interdisciplinary Nanoscience Centre (iNANO), Centre for Insoluble Protein Structures (inSPIN), Department of Molecular Biology and Genetics; Aarhus University; Denmark
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25
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Piaz FD, Vassallo A, Temraz A, Cotugno R, Belisario MA, Bifulco G, Chini MG, Pisano C, De Tommasi N, Braca A. A Chemical–Biological Study Reveals C9-type Iridoids as Novel Heat Shock Protein 90 (Hsp90) Inhibitors. J Med Chem 2013; 56:1583-95. [DOI: 10.1021/jm301398y] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fabrizio Dal Piaz
- Dipartimento di Farmacia, Università di Salerno, Via Ponte Don Melillo,
84084 Fisciano (SA), Italy
| | - Antonio Vassallo
- Dipartimento di Scienze, Università degli Studi della Basilicata, Viale
dell’Ateneo Lucano 10, 85100 Potenza, Italy
| | - Abeer Temraz
- Faculty of Pharmacy, Al Azhar University, Nasr-City, 11371 Cairo, Egypt
| | - Roberta Cotugno
- Dipartimento di Farmacia, Università di Salerno, Via Ponte Don Melillo,
84084 Fisciano (SA), Italy
| | - Maria A. Belisario
- Dipartimento di Farmacia, Università di Salerno, Via Ponte Don Melillo,
84084 Fisciano (SA), Italy
| | - Giuseppe Bifulco
- Dipartimento di Farmacia, Università di Salerno, Via Ponte Don Melillo,
84084 Fisciano (SA), Italy
| | - Maria G. Chini
- Dipartimento di Farmacia, Università di Salerno, Via Ponte Don Melillo,
84084 Fisciano (SA), Italy
| | - Claudio Pisano
- Sigma-Tau Research and Development, Via Pontina Km 30,400, 00040 Pomezia
(RM), Italy
| | - Nunziatina De Tommasi
- Dipartimento di Farmacia, Università di Salerno, Via Ponte Don Melillo,
84084 Fisciano (SA), Italy
| | - Alessandra Braca
- Dipartimento
di Farmacia, Università di Pisa,
Via Bonanno 33, 56126 Pisa,
Italy
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Permyakov SE, Knyazeva EL, Khasanova LM, Fadeev RS, Zhadan AP, Roche-Hakansson H, Håkansson AP, Akatov VS, Permyakov EA. Oleic acid is a key cytotoxic component of HAMLET-like complexes. Biol Chem 2013; 393:85-92. [PMID: 22628302 DOI: 10.1515/bc-2011-230] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 11/24/2011] [Indexed: 11/15/2022]
Abstract
HAMLET is a complex of α-lactalbumin (α-LA) with oleic acid (OA) that selectively kills tumor cells and Streptococcus pneumoniae. To assess the contribution of the proteinaceous component to cytotoxicity of HAMLET, OA complexes with proteins structurally and functionally distinct from α-LA were prepared. Similar to HAMLET, the OA complexes with bovine β-lactoglobulin (bLG) and pike parvalbumin (pPA) (bLG-OA-45 and pPA-OA-45, respectively) induced S. pneumoniae D39 cell death. The activation mechanisms of S. pneumoniae death for these complexes were analogous to those for HAMLET, and the cytotoxicity of the complexes increased with OA content in the preparations. The half-maximal inhibitory concentration for HEp-2 cells linearly decreased with rise in OA content in the preparations, and OA concentration in the preparations causing HEp-2 cell death was close to the cytotoxicity of OA alone. Hence, the cytotoxic action of these complexes against HEp-2 cells is induced mostly by OA. Thermal stabilization of bLG upon association with OA implies that cytotoxicity of bLG-OA-45 complex cannot be ascribed to molten globule-like conformation of the protein component. Overall, the proteinaceous component of HAMLET-like complexes studied is not a prerequisite for their activity; the cytotoxicity of these complexes is mostly due to the action of OA.
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Affiliation(s)
- Sergei E Permyakov
- Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow 142290, Russia.
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Faiella L, Piaz FD, Bisio A, Tosco A, De Tommasi N. A chemical proteomics approach reveals Hsp27 as a target for proapoptotic clerodane diterpenes. Mol Biosyst 2013; 8:2637-44. [PMID: 22802135 DOI: 10.1039/c2mb25171j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Clerodane diterpenoids are a class of naturally occurring molecules widely distributed in the Lamiaceae family. Neo-clerodane diterpenoids from Salvia ssp were recently described as compounds inhibiting the proliferation of human cancer cell lines. To gain new insights into molecular mechanism(s) underlying the antitumor potential of this class of compounds, we used a chemical proteomics approach to analyse the cellular interactome of hardwickiic acid (HAA) selected as a representative molecule. HAA was linked to an opportune 1,1'-carbonyldiimidazole modified by 1,12-dodecanediamine and then immobilized on a matrix support. The modified beads were then used as bait for fishing the potential partners of HAA in a U937 cell lysate. We identified heat shock protein 27 (Hsp27), an ATP-independent antiapoptotic chaperone characterized for its tumorigenic and metastatic properties and now referenced as a major therapeutic target in many types of cancer, as a major HAA partner. Here, we also report the study of HAA-Hsp27 interaction by means of a panel of chemical and biological approaches, including surface plasmon resonance measurements limited proteolysis, and biochemical assays. Our data suggest that HAA could provide a potential tool to develop strategies for the discovery of Hsp27 chemical inhibitors.
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Affiliation(s)
- Laura Faiella
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, via Bonanno 33, 56126 Pisa, Italy
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Stănciuc N, Aprodu I, Râpeanu G, Bahrim G. pH- and heat-induced structural changes of bovine α-lactalbumin in response to oleic acid binding. Eur Food Res Technol 2013; 236:257-66. [DOI: 10.1007/s00217-012-1882-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ho CS J, Rydström A, Trulsson M, Bålfors J, Storm P, Puthia M, Nadeem A, Svanborg C. HAMLET: functional properties and therapeutic potential. Future Oncol 2012; 8:1301-13. [DOI: 10.2217/fon.12.122] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Human α-lactalbumin made lethal to tumor cells (HAMLET) is the first member in a new family of protein–lipid complexes that kills tumor cells with high selectivity. The protein component of HAMLET is α-lactalbumin, which in its native state acts as a substrate specifier in the lactose synthase complex, thereby defining a function essential for the survival of lactating mammals. In addition, α-lactalbumin acquires tumoricidal activity after partial unfolding and binding to oleic acid. The lipid cofactor serves the dual role as a stabilizer of the altered fold of the protein and a coactivator of specific steps in tumor cell death. HAMLET is broadly tumoricidal, suggesting that the complex identifies conserved death pathways suitable for targeting by novel therapies. Sensitivity to HAMLET is defined by oncogene expression including Ras and c-Myc and by glycolytic enzymes. Cellular targets are located in the cytoplasmic membrane, cytoskeleton, mitochondria, proteasomes, lysosomes and nuclei, and specific signaling pathways are rapidly activated, first by interactions of HAMLET with the cell membrane and subsequently after HAMLET internalization. Therapeutic effects of HAMLET have been demonstrated in human skin papillomas and bladder cancers, and HAMLET limits the progression of human glioblastomas, with no evidence of toxicity for normal brain or bladder tissue. These findings open up new avenues for cancer therapy and the understanding of conserved death responses in tumor cells.
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Affiliation(s)
- James Ho CS
- Department of Microbiology, Immunology & Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
| | - Anna Rydström
- Department of Microbiology, Immunology & Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
| | - Maria Trulsson
- Department of Microbiology, Immunology & Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
| | - Johannes Bålfors
- Department of Microbiology, Immunology & Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
| | - Petter Storm
- Department of Microbiology, Immunology & Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
| | - Manoj Puthia
- Department of Microbiology, Immunology & Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
| | - Aftab Nadeem
- Department of Microbiology, Immunology & Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
| | - Catharina Svanborg
- Department of Microbiology, Immunology & Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sölvegatan 23, S-223 62 Lund, Sweden
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Fang B, Zhang M, Jiang L, Jing H, Ren FZ. Influence of pH on the Structure and Oleic Acid Binding Ability of Bovine α-Lactalbumin. Protein J 2012; 31:564-72. [DOI: 10.1007/s10930-012-9434-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Piaz FD, Malafronte N, Romano A, Gallotta D, Belisario MA, Bifulco G, Gualtieri MJ, Sanogo R, Tommasi ND, Pisano C. Structural characterization of tetranortriterpenes from Pseudrocedrela kotschyi and Trichilia emetica and study of their activity towards the chaperone Hsp90. Phytochemistry 2012; 75:78-89. [PMID: 22226245 DOI: 10.1016/j.phytochem.2011.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 12/07/2011] [Accepted: 12/08/2011] [Indexed: 05/31/2023]
Abstract
Investigation of roots extracts Pseudrocedrela kotschyi and Trichilia emetica led to identification of 5 limonoid derivatives, Kotschyins D-H, and 11 known compounds. Their structures were elucidated by extensive 1D and 2D NMR experiments in conjunction with mass spectrometry. A surface plasmon resonance (SPR) approach was adopted to screen their Hsp90 binding capability and kotschyin D showed a significant affinity for the chaperone. Therefore, the characterization of the biological activity of kotschyin D by means of a panel of chemical and biological approaches, including limited proteolysis, molecular docking and biochemical and cellular assays, was performed. Our result indicated this compound as a type of client selective Hsp90 inhibitor, directly binding to the middle domain of the protein and possibly preventing its interaction with the activator of Hsp90 ATPase 1 (Aha1).
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Affiliation(s)
- Fabrizio Dal Piaz
- Dipartimento di Scienze Farmaceutiche, Università di Salerno, Via Ponte Don Melillo, 84084 Fisciano, SA, Italy
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Barbana C, Sánchez L, Pérez MD. Bioactivity of α-Lactalbumin Related to its Interaction with Fatty Acids: A Review. Crit Rev Food Sci Nutr 2011; 51:783-94. [DOI: 10.1080/10408398.2010.481368] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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34
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Brinkmann CR, Heegaard CW, Petersen TE, Jensenius JC, Thiel S. The toxicity of bovine α-lactalbumin made lethal to tumor cells is highly dependent on oleic acid and induces killing in cancer cell lines and noncancer-derived primary cells. FEBS J 2011; 278:1955-67. [DOI: 10.1111/j.1742-4658.2011.08112.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Mossberg AK, Hun Mok K, Morozova-Roche LA, Svanborg C. Structure and function of human α-lactalbumin made lethal to tumor cells (HAMLET)-type complexes. FEBS J 2010; 277:4614-25. [PMID: 20977665 DOI: 10.1111/j.1742-4658.2010.07890.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Human α-lactalbumin made lethal to tumor cells (HAMLET) and equine lysozyme with oleic acid (ELOA) are complexes consisting of protein and fatty acid that exhibit cytotoxic activities, drastically differing from the activity of their respective proteinaceous compounds. Since the discovery of HAMLET in the 1990s, a wealth of information has been accumulated, illuminating the structural, functional and therapeutic properties of protein complexes with oleic acid, which is summarized in this review. In vitro, both HAMLET and ELOA are produced by using ion-exchange columns preconditioned with oleic acid. However, the complex of human α-lactalbumin with oleic acid with the antitumor activity of HAMLET was found to be naturally present in the acidic fraction of human milk, where it was discovered by serendipity. Structural studies have shown that α-lactalbumin in HAMLET and lysozyme in ELOA are partially unfolded, 'molten-globule'-like, thereby rendering the complexes dynamic and in conformational exchange. HAMLET exists in the monomeric form, whereas ELOA mostly exists as oligomers and the fatty acid stoichiometry varies, with HAMLET holding an average of approximately five oleic acid molecules, whereas ELOA contains a considerably larger number (11- 48). Potent tumoricidal activity is found in both HAMLET and ELOA, and HAMLET has also shown strong potential as an antitumor drug in different in vivo animal models and clinical studies. The gain of new, beneficial function upon partial protein unfolding and fatty acid binding is a remarkable phenomenon, and may reflect a significant generic route of functional diversification of proteins via varying their conformational states and associated ligands.
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Affiliation(s)
- Ann-Kristin Mossberg
- Department of Microbiology, Immunology and Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Lund, Sweden.
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36
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Spolaore B, Pinato O, Canton M, Zambonin M, Polverino de Laureto P, Fontana A. α-Lactalbumin Forms with Oleic Acid a High Molecular Weight Complex Displaying Cytotoxic Activity. Biochemistry 2010; 49:8658-67. [DOI: 10.1021/bi1012832] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Pettersson-Kastberg J, Mossberg AK, Trulsson M, Yong YJ, Min S, Lim Y, O'Brien JE, Svanborg C, Mok KH. α-Lactalbumin, Engineered to be Nonnative and Inactive, Kills Tumor Cells when in Complex with Oleic Acid: A New Biological Function Resulting from Partial Unfolding. J Mol Biol 2009; 394:994-1010. [DOI: 10.1016/j.jmb.2009.09.026] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Revised: 08/18/2009] [Accepted: 09/14/2009] [Indexed: 11/28/2022]
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38
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Atri MS, Saboury AA, Yousefi R, Dalgalarrondo M, Chobert J, Haertlé T, Moosavi-movahedi AA. Comparative study on heat stability of camel and bovine apo and holo α-lactalbumin. J DAIRY RES 2010; 77:43-9. [DOI: 10.1017/s0022029909990367] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The stability of camel α-lactalbumin (α-la) against heat denaturation was measured, using circular dichroism (CD) and fluorescence spectroscopy, as well as differential scanning calorimetry (DSC). The experiments were performed in the presence of saturating concentrations of calcium as well as in the presence of EDTA, yielding to the apo form of α-la. The change in heat capacity (ΔCp) suggests a greater contribution of hydrophobic interactions to the stability of holo camel α-la than in its bovine counterpart. Overall the results obtained in this study suggest a greater stability of camel α-la than the bovine protein in both holo and apo states. Also CD experiments showed similar secondary structure for camel and bovine α-la and secondary structure of camel α-la was better preserved than that of bovine α-la during heat denaturation. The differences in thermal stability between the proteins from two species can be primarily ascribed to the difference in the quantity of hydrophobic interactions involved in their folding.
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39
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Salami M, Yousefi R, Ehsani MR, Razavi SH, Chobert JM, Haertlé T, Saboury AA, Atri MS, Niasari-Naslaji A, Ahmad F, Moosavi-Movahedi AA. Enzymatic digestion and antioxidant activity of the native and molten globule states of camel α-lactalbumin: Possible significance for use in infant formula. Int Dairy J 2009. [DOI: 10.1016/j.idairyj.2009.02.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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40
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Zherelova OM, Kataev AA, Grishchenko VM, Knyazeva EL, Permyakov SE, Permyakov EA. Interaction of antitumor α-lactalbumin—oleic acid complexes with artificial and natural membranes. J Bioenerg Biomembr 2009; 41:229-37. [DOI: 10.1007/s10863-009-9222-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 06/03/2009] [Indexed: 10/20/2022]
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41
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Knyazeva EL, Grishchenko VM, Fadeev RS, Akatov VS, Permyakov SE, Permyakov EA. Who Is Mr. HAMLET? Interaction of Human α-Lactalbumin with Monomeric Oleic Acid. Biochemistry 2008; 47:13127-37. [DOI: 10.1021/bi801423s] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ekaterina L. Knyazeva
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, and Pushchino State University, Pushchino, Moscow Region 142290, Russia
| | - Valery M. Grishchenko
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, and Pushchino State University, Pushchino, Moscow Region 142290, Russia
| | - Roman S. Fadeev
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, and Pushchino State University, Pushchino, Moscow Region 142290, Russia
| | - Vladimir S. Akatov
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, and Pushchino State University, Pushchino, Moscow Region 142290, Russia
| | - Sergei E. Permyakov
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, and Pushchino State University, Pushchino, Moscow Region 142290, Russia
| | - Eugene A. Permyakov
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, and Pushchino State University, Pushchino, Moscow Region 142290, Russia
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42
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Monti MC, Riccio R, Casapullo A. Effects of petrosaspongiolide R on the surface topology of bee venom PLA(2): a limited proteolysis and mass spectrometry analysis. Bioorg Chem 2009; 37:6-10. [PMID: 18945473 DOI: 10.1016/j.bioorg.2008.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 09/02/2008] [Accepted: 09/07/2008] [Indexed: 11/21/2022]
Abstract
Petrosaspongiolides are sponge metabolites belonging to the family of the gamma-hydroxybutenolide marine terpenoids. They possess a remarkable in vitro and in vivo anti-inflammatory profile, due to the specific inhibition of group II and III secretory phospholipase A(2) enzymes, and for this reason can be considered as potential lead for the development of anti-inflammatory drugs. The molecular mechanism of bee venom phospholipase A(2) inactivation has been identified, and the ligand-enzyme complex formation is guided by either non-covalent and covalent interactions. In this work we have analyzed the conformational changes induced by petrosaspongiolide R on the bee venom phospholipase A(2) topology during the molecular recognition process, through the application of limited proteolysis and mass spectrometric methodologies. The results are indicative of structural changes at the N- and C-terminal domains producing a more compact conformational arrangement of the enzyme.
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43
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Mok KH, Pettersson J, Orrenius S, Svanborg C. HAMLET, protein folding, and tumor cell death. Biochem Biophys Res Commun 2006; 354:1-7. [PMID: 17223074 DOI: 10.1016/j.bbrc.2006.12.167] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Accepted: 12/18/2006] [Indexed: 11/18/2022]
Affiliation(s)
- K Hun Mok
- Trinity College, School of Biochemistry and Immunology, University of Dublin, Dublin 2, Ireland
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44
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Pettersson J, Mossberg AK, Svanborg C. α-Lactalbumin species variation, HAMLET formation, and tumor cell death. Biochem Biophys Res Commun 2006; 345:260-70. [PMID: 16678133 DOI: 10.1016/j.bbrc.2006.04.081] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Accepted: 04/14/2006] [Indexed: 11/17/2022]
Abstract
HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a tumoricidal complex of apo alpha-lactalbumin and oleic acid, formed in casein after low pH treatment of human milk. This study examined if HAMLET-like complexes are present in casein from different species and if isolated alpha-lactalbumin from those species can form such complexes with oleic acid. Casein from human, bovine, equine, and porcine milk was separated by ion exchange chromatography and active complexes were only found in human casein. This was not explained by alpha-lactalbumin sequence variation, as purified bovine, equine, porcine, and caprine alpha-lactalbumins formed complexes with oleic acid with biological activity similar to HAMLET. We conclude that structural variation of alpha-lactalbumins does not preclude the formation of HAMLET-like complexes and that natural HAMLET formation in casein was unique to human milk, which also showed the highest oleic acid content.
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Affiliation(s)
- Jenny Pettersson
- Department of Microbiology, Immunology and Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Sweden
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45
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Halskau O, Underhaug J, Frøystein NA, Martínez A. Conformational flexibility of alpha-lactalbumin related to its membrane binding capacity. J Mol Biol 2005; 349:1072-86. [PMID: 15913646 DOI: 10.1016/j.jmb.2005.04.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 04/04/2005] [Accepted: 04/12/2005] [Indexed: 10/25/2022]
Abstract
Different folding states of the small, globular milk protein bovine alpha-lactalbumin (BLA) induced by the anionic surfactant sodium dodecylsulphate (SDS) have been examined by fluorescence spectroscopy, CD and NMR. The solution structure of the protein in the absence of SDS was also determined, indicating fluidity even under native conditions. BLA is partly denatured to a molten globule (MG)-like state by micromolar concentrations of SDS, and the transitions from native to MG-like state are dependent on pH, the protein being more sensitive to the surfactant at pH 6.5. As indicated by measurements of the intrinsic emission fluorescence, the tertiary structure disappears at lower concentrations of SDS than most of the secondary structure, as estimated from CD data. The MG-like state induced by low concentrations of SDS is not observable by NMR, and is probably fluctuating and/or aggregating. At higher concentrations of SDS above the critic concentration of micelles, an NMR-observable state reappears. This micelle-associated conformer was partially assigned, and found to bear strong resemblance to the acid-tri-fluoroethanol state, retaining weakened versions of the A and C helix of native BLA. We discuss the results in terms of the inherent flexibility of the protein, and its ability to form multiple folding states and to bind to membranes. Also, we propose that proteins with stable MG-like conformers can have these states stabilized by low levels of compounds with surfactant properties in vivo.
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Affiliation(s)
- Oyvind Halskau
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
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46
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Chen WL, Hwang MT, Liau CY, Ho JC, Hong KC, Mao SJT. Beta-lactoglobulin is a thermal marker in processed milk as studied by electrophoresis and circular dichroic spectra. J Dairy Sci 2005; 88:1618-30. [PMID: 15829652 DOI: 10.3168/jds.s0022-0302(05)72833-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
As much of the sterilization process involves heat treatment during the preparation of milk on an industrial scale, the unpredictable measures of the process are an essential issue in determining the quality of the milk. The purpose of the present study was to investigate the major protein change(s) of whey proteins in processed milk and extend the knowledge for future reference in the dairy industry. Using a native polyacrylamide gel electrophoresis, we showed almost a 90% loss and denaturation of beta-lactoglobulin (LG), but not alpha-lactalbumin (LA), in some brands of the processed and dry milks. Immunochemical analysis using Western blotting revealed that part of the loss was attributed to the formation of large multiple forms of LG in the processed product. Such denaturation was presumably associated with the heating procedure used in the process. Essentially, LG was the only major fraction converted to aggregates in milk heated at 95 degrees C for 30 min on 2-dimensional PAGE. The detailed thermal denaturation of purified LG and LA at various temperatures (50 to 95 degrees C) and time (5 to 960 s) were investigated using a circular dichroic analysis. The maximal changes of ellipticity at 205 nm (converting beta-structure to disordered structure) were correlated to heating temperature and time. There were no significant conformational changes of LG at temperatures below 70 degrees C for as long as 480 s. Pronounced and rapid changes occurred between 80 to 95 degrees C in a time-dependent manner. Fifty percent of the maximal changes could be reached within 15 s. In conclusion, the unique chemical and immunochemical loss and conformational changes made LG a superior marker for evaluating the thermal processing of milk. The detailed thermal denaturation curves of LG constructed with its time and temperature in this study provide a valuable reference for the dairy industry. We postulate that heat treatment over 80 degrees C in 15 s may induce a significant denaturation of milk LG.
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Affiliation(s)
- W L Chen
- Research Institute of Biochemical Engineering, Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
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