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Pulmonary delivery of siRNA against acute lung injury/acute respiratory distress syndrome. Acta Pharm Sin B 2022; 12:600-620. [PMID: 34401226 PMCID: PMC8359643 DOI: 10.1016/j.apsb.2021.08.009] [Citation(s) in RCA: 93] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/14/2021] [Accepted: 07/02/2021] [Indexed: 02/08/2023] Open
Abstract
The use of small interfering RNAs (siRNAs) has been under investigation for the treatment of several unmet medical needs, including acute lung injury/acute respiratory distress syndrome (ALI/ARDS) wherein siRNA may be implemented to modify the expression of pro-inflammatory cytokines and chemokines at the mRNA level. The properties such as clear anatomy, accessibility, and relatively low enzyme activity make the lung a good target for local siRNA therapy. However, the translation of siRNA is restricted by the inefficient delivery of siRNA therapeutics to the target cells due to the properties of naked siRNA. Thus, this review will focus on the various delivery systems that can be used and the different barriers that need to be surmounted for the development of stable inhalable siRNA formulations for human use before siRNA therapeutics for ALI/ARDS become available in the clinic.
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Key Words
- AAV, adeno-associated virus
- ALI/ARDS
- ALI/ARDS, acute lung injury/acute respiratory distress syndrome
- AM, alveolar macrophage
- ATI, alveolar cell type I
- ATII, alveolar cell type II
- AV, adenovirus
- Ago-2, argonaute 2
- CFDA, China Food and Drug Administration
- COPD, chronic obstructive pulmonary disease
- CPP, cell-penetrating peptide
- CS, cigarette smoke
- CXCR4, C–X–C motif chemokine receptor type 4
- Cellular uptake
- DAMPs, danger-associated molecular patterns
- DC-Chol, 3β-(N-(N′,N′-dimethylethylenediamine)-carbamoyl) cholesterol
- DDAB, dimethyldioctadecylammonium bromide
- DODAP, 1,2-dioleyl-3-dimethylammonium-propane
- DODMA, 1,2-dioleyloxy-N,N-dimethyl-3-aminopropane
- DOGS, dioctadecyl amido glycin spermine
- DOPC, 1,2-dioleoyl-sn-glycero-3-phosphocholine
- DOPE, 1,2-dioleoyl-l-α-glycero-3-phosphatidylethanolamine
- DOSPA, 2,3-dioleyloxy-N-[2-(sperminecarboxamido)ethyl]-N,N-dimethyl-1-propanaminium
- DOTAP, 1,2-dioleoyl-3-trimethylammonium-propane
- DOTMA, N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium
- DPI, dry powder inhaler
- DPPC, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine
- Drug delivery
- EC, endothelial cell
- EPC, egg phosphatidylcholine
- EXOs, exosomes
- Endosomal escape
- EpiC, epithelial cell
- FDA, US Food and Drug Administration
- HALI, hyperoxic acute lung injury
- HMGB1, high-mobility group box 1
- HMVEC, human primary microvascular endothelial cell
- HNPs, hybrid nanoparticles
- Hem-CLP, hemorrhagic shock followed by cecal ligation and puncture septic challenge
- ICAM-1, intercellular adhesion molecule-1
- IFN, interferons
- Inflammatory diseases
- LPS, lipopolysaccharides
- MEND, multifunctional envelope-type nano device
- MIF, macrophage migration inhibitory factor
- Myd88, myeloid differentiation primary response 88
- N/P ratio, nitrogen /phosphate ratio
- NETs, neutrophil extracellular traps
- NF-κB, nuclear factor kappa B
- NPs, nanoparticles
- Nanoparticles
- PAI-1, plasminogen activator inhibitor-1
- PAMAM, polyamidoamine
- PAMPs, pathogen-associated molecular patterns
- PD-L1, programmed death ligand-1
- PDGFRα, platelet-derived growth factor receptor-α
- PEEP, positive end-expiratory pressure
- PEG, polyethylene glycol
- PEI, polyethyleneimine
- PF, pulmonary fibrosis
- PFC, perfluorocarbon
- PLGA, poly(d,l-lactic-co-glycolic acid)
- PMs, polymeric micelles
- PRR, pattern recognition receptor
- PS, pulmonary surfactant
- Pulmonary administration
- RIP2, receptor-interacting protein 2
- RISC, RNA-induced silencing complex
- RNAi, RNA interference
- ROS, reactive oxygen species
- SLN, solid lipid nanoparticle
- SNALP, stable nucleic acid lipid particle
- TGF-β, transforming growth factor-β
- TLR, Toll-like receptor
- TNF-α, tumor necrosis factor-α
- VALI, ventilator-associated lung injury
- VILI, ventilator-induced lung injury
- dsDNA, double-stranded DNA
- dsRNA, double-stranded RNA
- eggPG, l-α-phosphatidylglycerol
- mRNA, messenger RNA
- miRNA, microRNA
- pDNA, plasmid DNA
- shRNA, short RNA
- siRNA
- siRNA, small interfering RNA
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Digital PCR can provide improved BCR-ABL1 detection in chronic myeloid leukemia patients in deep molecular response and sensitivity of standard quantitative methods using EAC assays. Pract Lab Med 2021; 25:e00210. [PMID: 33778144 PMCID: PMC7985703 DOI: 10.1016/j.plabm.2021.e00210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/04/2021] [Indexed: 11/25/2022] Open
Abstract
BCR-ABL1 molecular detection using quantitative PCR (qPCR) methods is the golden standard of chronic myeloid leukemia (CML) monitoring. However, due to variable sensitivity of qPCR assays across laboratories, alternative methods are tested. Digital PCR (dPCR) has been suggested as a robust and reproducible option. Here we present a comparison of droplet dPCR with routinely used reverse-transcription qPCR (RT-qPCR) and automated GeneXpert systems. Detection limit of dPCR was above 3 BCR-ABL1 copies, although due to background amplification the resulting sensitivity was 0.01% BCR-ABL1 (MR4.0). Nevertheless, in comparison with GeneXpert, dPCR categorized more than 50% of the patients into different MR groups, showing a potential for improved BCR-ABL1 detection. dPCR assays attain MR4.0 sensitivity due to a blank amplification 3 BCR-ABL1 copies. Quantification principle of RT-qPCR and dPCR introduces bias in copy numbers. dPCR provides more sensitive BCR-ABL1 measurement in >50% MR3.0-MR4.5 CML patients.
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Key Words
- BCR-ABL1 monitoring
- CML, chronic myeloid leukemia
- Chronic myeloid leukemia
- Digital PCR
- EAC, Europe Against Cancer
- FPR, false positivity rate
- GeneXpert BCR-ABL Monitor assay
- IS, international scale
- LOB, limit of blank
- LOD, limit of detection
- MR, molecular response
- NTC, no template control
- RT-qPCR
- RT-qPCR, reverse-transcription quantitative PCR
- TKI, tyrosine kinase inhibitors
- cDNA, complementary DNA
- dPCR, digital PCR
- pDNA, plasmid DNA
- qPCR, quantitative PCR
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Dual-targeting and microenvironment-responsive micelles as a gene delivery system to improve the sensitivity of glioma to radiotherapy. Acta Pharm Sin B 2019; 9:381-396. [PMID: 30972284 PMCID: PMC6437633 DOI: 10.1016/j.apsb.2018.12.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/12/2018] [Accepted: 11/20/2018] [Indexed: 12/18/2022] Open
Abstract
Dbait is a small double-stranded DNA molecule that has been utilized as a radiosensitizer to enhance the sensitivity of glioma to radiotherapy (RT). However, there is no effective drug delivery system to effectively overcome the blood-brain barrier (BBB). The aim of this study was to develop a gene delivery system by using the BBB and glioma dual-targeting and microenvironment-responsive micelles (ch-Kn(s-s)R8-An) to deliver Dbait into glioma for RT. Angiopep-2 can target the low-density lipoprotein receptor-related protein-1 (LRP1) that is overexpressed on brain capillary endothelial cells (BCECs) and glioma cells. In particular, due to upregulated matrix metalloproteinase 2 (MMP-2) in the tumor microenvironment, we utilized MMP-2-responsive peptides as the enzymatically degradable linkers to conjugate angiopep-2. The results showed that ch-Kn(s-s)R8-An micelles maintained a reasonable size (80-160 nm) with a moderate distribution and a decreased mean diameter from the cross-linking as well as exhibited low critical micelle concentration (CMC) with positive surface charge, ranging from 15 to 40 mV. The ch-K5(s-s)R8-An/pEGFP showed high gene transfection efficiency in vitro, improved uptake in glioma cells and good biocompatibility in vitro and in vivo. In addition, the combination of ch-K5(s-s)R8-An/Dbait with RT significantly inhibited the growth of U251 cells in vitro. Thus, ch-K5(s-s)R8-An/Dbait may prove to be a promising gene delivery system to target glioma and enhance the efficacy of RT on U251 cells.
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Key Words
- ATCC, American Type Culture Collection
- Arg, arginine
- BBB, blood–brain barrier
- BBTB, blood—brain tumor barriers
- CMC, critical micelle concentration
- Cell-penetrating peptides
- DTSSP, 3,3′-dithiobis(sulfosuccinimidylpropionate)
- DTT, dithiothreitol
- FBS, fetal bovine serum
- GBM, glioblastoma multiforme
- GSH, glutathione
- Gene delivery
- Glioma-targeting
- KnR8, cholesterol-polylysine-polyarginine peptide, n = 3, 5, 7
- Lys, lysine
- MMP-2, matrix metalloproteinase 2
- MWCO, molecular weight cutoff
- Microenvironment-responsive micelles
- PDI, polydispersity index
- PE, plating efficiency
- PEI, polyethylenimine
- RT, radiotherapy
- Radiosensitizer
- ch-Kn(s-s)R8-An, the disulfide cross-linked cholesterol-polylysine-polyarginine peptide core-shell polymer micelles modified with angiopep-2, n = 3, 5, 7
- ch-KnR8-An, the non-cross-linked cholesterol-polylysine-polyarginine peptide core-shell polymer micelles modified with angiopep-2, n = 3, 5, 7
- pDNA, plasmid DNA
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Intracellular distribution and internalization pathways of guanidinylated bioresponsive poly(amido amine)s in gene delivery. Asian J Pharm Sci 2018; 13:360-372. [PMID: 32104410 PMCID: PMC7032094 DOI: 10.1016/j.ajps.2018.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 11/26/2017] [Accepted: 02/26/2018] [Indexed: 12/11/2022] Open
Abstract
Guanidinylated bioresponsive poly(amido amine)s polymers, CAR-CBA and CHL-CBA, were synthesized by Michael-type addition reaction between guanidine hydrochloride (CAR) or chlorhexidine (CHL) and N,N'-cystaminebisacrylamide (CBA). Previous studies have shown that both polymers had high transfection efficiencies as gene delivery carriers. In this study, we investigated the nucleolus localization abilities and cellular internalization pathways of these two polymers in gene delivery. Each polymer condensed plasmid DNA (pDNA) and formed nanoparticle complexes, and then their transfection studies were performed in MCF-7 cells. Both complexes were found enriched in nucleolus after cellular transfection, and their transfection efficiencies were significantly improved when transfection was performed on MCF-7 cells arrested at M phase. The transfection efficiency of CAR-CBA-pDNA was inhibited by chlorpromazine, and cell endosomes were disrupted after being exposed to CAR-CBA-pDNA. In regards to CHL-CBA-pDNA, its transfection efficiency was not affected by three types of endocytosis inhibitors used in the study, and CHL-CBA-pDNA showed no effect on endosomes. Cellular lactate dehydrogenase release and membrane morphology were changed after cells were transfected by the two complexes. The results indicated that both CAR-CBA and CHL-CBA polymers demonstrated good nucleolus localization abilities. It was beneficial for transfection when cells were arrested at M phase. CAR-CBA-pDNA cellular internalization was involved with clathrin-mediated endocytosis pathway, and escaping from endosomal entrapment, while the cellular uptake of CHL-CBA-pDNA occurs via clathrin- and caveolae-independent mechanism.
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Key Words
- AFM, atomic force microscopy
- CAR, guanidine hydrochloride
- CBA, N,N’-cystaminebisacrylamide
- CHL, chlorhexidine
- CPPs, cell- penetrating peptides
- Cell cycle status
- DAPI, 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride
- DLS, dynamic light scattering
- DMEM, Dulbecco's Modification of Eagle's medium
- DiI, 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate
- EGFP, enhanced green fluorescent protein
- Gua-SS-PAAs, guanidinylated disulfide containing poly(amido amine) polymers
- Guanidinylated poly(amido amine)s polymers
- Internalization pathways
- LDH, Lactate dehydrogenase
- NMR, nuclear magnetic resonance
- NOR, nucleolar organizing region
- Nucleolus localization
- OD, optical density
- PAAs, poly(amido, amine)s
- SS-PAAs, disulfide containing poly(amido, amine)
- pDNA, plasmid DNA
- rRNA, ribosomal RNA
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Mesoporous silica nanoparticles for drug and gene delivery. Acta Pharm Sin B 2018; 8:165-177. [PMID: 29719777 PMCID: PMC5926503 DOI: 10.1016/j.apsb.2018.01.007] [Citation(s) in RCA: 371] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/26/2017] [Accepted: 01/22/2018] [Indexed: 01/05/2023] Open
Abstract
Mesoporous silica nanoparticles (MSNs) are attracting increasing interest for potential biomedical applications. With tailored mesoporous structure, huge surface area and pore volume, selective surface functionality, as well as morphology control, MSNs exhibit high loading capacity for therapeutic agents and controlled release properties if modified with stimuli-responsive groups, polymers or proteins. In this review article, the applications of MSNs in pharmaceutics to improve drug bioavailability, reduce drug toxicity, and deliver with cellular targetability are summarized. Particularly, the exciting progress in the development of MSNs-based effective delivery systems for poorly soluble drugs, anticancer agents, and therapeutic genes are highlighted.
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Key Words
- AO, acridine orange
- APTES, 3-aminopropyltriethoxysilane
- APTMS, amino propyl trimethoxysilane
- BCL-2, B-cell lymphoma-2
- BCS, Biopharmaceutical Classification System
- Bio-TEM, biological transmission electron microscopy
- C dots, Cornell dots
- CMC, critical micelle concentration
- CPT, camptothecin
- CTAB, cetyltrimethyl ammonium bromide
- Cancer therapy
- EPR, enhanced permeability and retention
- FDA, Food and Drug Administration
- GI, gastrointestinal
- GNRs@mSiO2, mesoporous silica-encapsulated gold nanorods
- Gene delivery
- LHRH, luteinising-hormone releasing hormone
- MDR, multi-drug resistance
- MRP1, multidrug resistance protein 1
- MSN-Dox-G2, Dox-loaded and G2 PAMAM-modified MSNs
- MSNs, mesoporous silica nanoparticles
- MSNs-HA, hyaluronic acid-conjugated MSNs
- MSNs-RGD/TAT, RGD/TAT peptide-modified MSNs
- MSNs-TAT, TAT peptide-modified MSNs
- MSNs@PDA-PEG-FA, poly(ethylene glycol)-folic acid-functionalized polydopamine-modified MSNs
- MTT, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide
- Mesoporous silica nanoparticles
- Multidrug resistance
- NIR, near-infrared
- P-gp, P-glycoprotein
- PAMAM, polyamidoamine
- PDEAEMA, poly (2-(diethylamino)ethylmethacrylate)
- PDMAEMA, poly(2-(dimethylamino)ethylmethacrylate)
- PEG400, polyethylene glycol 400
- PEI, polyethyleneimine
- PLL, poly-l-lysine
- PTX, paclitaxel
- Poorly soluble drug
- Q-MSNs, quercetin encapsulated MSNs
- RGD, arginine-glycine-aspartate
- TAT, trans-activating transcriptor
- TMB, 1,3,5-trimethybenzene
- pDNA, plasmid DNA
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Biomacromolecules as carriers in drug delivery and tissue engineering. Acta Pharm Sin B 2018; 8:34-50. [PMID: 29872621 PMCID: PMC5985630 DOI: 10.1016/j.apsb.2017.11.005] [Citation(s) in RCA: 213] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/05/2017] [Accepted: 10/07/2017] [Indexed: 12/14/2022] Open
Abstract
Natural biomacromolecules have attracted increased attention as carriers in biomedicine in recent years because of their inherent biochemical and biophysical properties including renewability, nontoxicity, biocompatibility, biodegradability, long blood circulation time and targeting ability. Recent advances in our understanding of the biological functions of natural-origin biomacromolecules and the progress in the study of biological drug carriers indicate that such carriers may have advantages over synthetic material-based carriers in terms of half-life, stability, safety and ease of manufacture. In this review, we give a brief introduction to the biochemical properties of the widely used biomacromolecule-based carriers such as albumin, lipoproteins and polysaccharides. Then examples from the clinic and in recent laboratory development are summarized. Finally the current challenges and future prospects of present biological carriers are discussed.
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Key Words
- ABD, albumin binding domain
- ACM, aclacinomycin
- ACS, absorbable collagen sponge
- ADH, adipic dihydrazide
- ART, artemisinin
- ASF, Antheraea mylitta silk fibroin
- ATRA, all-trans retinoic acid
- ATS, artesunate
- BCEC, brain capillary endothelial cells
- BMP-2, bone morphogenetic protein-2
- BSA, bovine serum albumin
- BSF, Bombyx mori silk fibroin
- Biomacromolecule
- CC-HAM, core-crosslinked polymeric micelle based hyaluronic acid
- CD, cyclodextrin
- CD-NPs, amphiphilic MMA–tBA β-CD star copolymers that are capable of forming nanoparticles
- CD-g-CS, chitosan grafted with β-cyclodextrin
- CD/BP, cyclodextrin–bisphosphonate complexes
- CIA, collagen-induced arthritis
- CM, collagen matrices
- CMD-ChNP, carboxylmethyl dextran chitosan nanoparticle
- DHA, dihydroartesunate
- DOXO-EMCH, (6-maleimidocaproyl)hydrazone derivative of doxorubicin
- DOX–TRF, doxorubincin–transferrin conjugate
- DTX-HPLGA, HA coated PLGA nanoparticulate docetaxel
- Drug delivery
- ECM, extracellular matrix
- EMT, epithelial mesenchymal transition
- EPR, enhanced permeability and retention
- FcRn, neonatal Fc receptor
- GAG, glycosaminoglycan
- GC-DOX, glycol–chitosan–doxorubicin conjugate
- GDNF, glial-derived neurotrophic factor
- GO, grapheme oxide
- GSH, glutathione
- Gd, gadolinium
- HA, hyaluronic acid
- HA-CA, catechol-modified hyaluronic acid
- HCF, heparin-conjugated fibrin
- HDL, high density lipoprotein
- HEK, human embryonic kidney
- HSA, human serum albumin
- IDL, intermediate density lipoprotein
- INF, interferon
- LDL, low density lipoprotein
- LDLR, low density lipoprotein receptor
- LDV, leucine–aspartic acid–valine
- LMWH, low molecular weight heparin
- MSA, mouse serum albumin
- MTX–HSA, methotrexate–albumin conjugate
- NIR, near-infrared
- NSCLC, non-small cell lung cancer
- OP-Gel-NS, oxidized pectin-gelatin-nanosliver
- PEC, polyelectrolyte
- PTX, paclitaxel
- Polysaccharide
- Protein
- RES, reticuloendothelial system
- RGD, Arg–Gly–Asp peptide
- SF, silk fibroin
- SF-CSNP, silk fibroin modified chitosan nanoparticle
- SFNP, silk fibroin nanoparticle
- SPARC, secreted protein acidic and rich in cysteine
- TRAIL, tumor-necrosis factor-related apoptosis-inducing ligand
- Tf, transferrin
- TfR, transferrin receptor
- Tissue engineering
- VEGF, vascular endothelial growth factor
- VLDL, very low density lipoprotein
- pDNA, plasmid DNA
- rHDL, recombinant HDL
- rhEGF-2/HA, recombinant human fibroblast growth factor type 2 in a hyaluronic acid carrier
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Abstract
The chemical nature of genetic drugs (e.g. antisense oligonucleotides, siRNA, vectors) requires a suitable carrier system to protect them from enzymatic degradation without changing their properties and enable efficient delivery into target cells. Lipid vectors for nucleic acid delivery that have been widely investigated for years can be very effective. As the majority of attempts made in the field of cancer gene therapy have focused on solid tumors, while blood cancer cells have attracted less attention, the latter became the subject of our investigation. The lipid carrier proposed here is based on liposomes constructed by others but the lipid composition is original. A liposome-coated lipoplex (L-cL) consists of a core arising from complexation of positively charged lipid and negatively charged oligodeoxynucleotide (ODN) or plasmid DNA coated by a neutral or anionic lipid bilayer. Moreover, our lipid vector demonstrates size stability and is able to retain a high content of enclosed plasmid DNA or antisense oligodeoxynucleotides (asODNs). Observed transfection efficacies of the tested preparation using a plasmid coding for fluorescent protein were up to 60-85% of examined leukemia cells (Jurkat T and HL-60 lines) in the absence or the presence of serum. When BCL‑2 asODN was encapsulated in the L-cL, specific silencing of this gene product at both the mRNA and protein level and also a markedly decreased cell survival rate were observed in vitro. Moreover, biodistribution analysis in mice indicates prolonged circulation characteristic for PEG-modified liposomal carriers. Experiments on tumor-engrafted animals indicate substantial inhibition of tumor growth.
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Key Words
- AML, acute myeloid leukemia
- BCL-2 gene
- Bcl-2, B-cell lymphoma 2 protein
- CCL, coated cationic liposomes
- DC-CHOL, 3β-(N-[dimethylaminoethane]carbamoyl)cholesterol) DiD-1,1′, dioctadecyl-3,3,3′, 3′-tetramethylindodicarbocyanine
- DOPE, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine)
- DOTAP, 1, 2-dioleoyl-3-trimethylammonium-propane)
- DSPE, PEG-(1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)2000] (ammonium salt)
- GFP, green fluorescent protein
- HPC, hydrogenated egg phosphatidylcholine)
- L-cL, liposome-coated lipoplex
- PE/PC, phosphatidylethanolamine and phosphatidylcholine liposomes
- acute leukemia
- antisense deoxynucleotides
- asODN, antisense oligodeoxynucleotide
- cationic lipids
- gene therapy
- lipid carrier
- lipoplex
- liposome coated lipoplex
- pDNA, plasmid DNA
- siRNA, small interferingRNA TGI, tumor growth inhibition
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The VTLISFG motif in the BH1 domain plays a significant role in regulating the degradation of Mcl-1. FEBS Open Bio 2014; 4:147-52. [PMID: 24490139 PMCID: PMC3907746 DOI: 10.1016/j.fob.2014.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 01/16/2014] [Accepted: 01/16/2014] [Indexed: 11/26/2022] Open
Abstract
Mcl-1 is a member of the Bcl-2 family protein; its degradation is required for the initiation of apoptosis. The mechanism, however, is not yet clearly known. Previously, it was reported that Mcl-1 is degraded through the ubiquitination-mediated pathway and the PEST domain is the motif responsible for promoting this degradation. We found evidence that this may not be true. We generated several Mcl-1 deletion mutants and examined their effects on protein stability. Deletion of the PEST domain did not prevent the degradation of Mcl-1 during apoptosis. The BH1 domain, but not the PEST, BH3 or BH2 domain, exhibited a short half-life. A peptide named “F3” (VTLISFG) in the C-terminus of the BH1 domain appears to be critical for the rapid turnover of Mcl-1. Deletion of F3 from GFP-Mcl-1-ΔPEST retarded the degradation of this mutant. F3 appeared to be the minimum functional sequence of the degradation motif, since deletion of a single residue was sufficient to abrogate its short half-life. Fusion of F3 with p32 resulted in the degradation of p32 during UV-induced apoptosis, while wild type p32 was not affected. Taken together, these findings suggest that F3 (VTLISFG), instead of PEST, is the major motif responsible for the degradation of Mcl-1 during apoptosis. The PEST domain may not be responsible for the short half-life of Mcl-1 during apoptosis. A short peptide (F3) inside the BH1 domain was found to have a short half-life. Fusion of F3 with p32 impairs the stability of p32 during apoptosis. Deletion of F3 increases the stability of GFP-Mcl-1-ΔPEST.
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Key Words
- Apoptosis
- BH domain, Bcl-2 homology domain
- BSA, bovine serum albumin
- Bax, Bcl-2-associated X protein
- Bcl-2, B-cell lymphoma-2
- Bim, Bcl-2-interacting mediator
- CCD, charge-coupled device
- Caspase, cysteine aspartase
- Degradation motif
- EGFP, enhanced green fluorescent protein
- EIF2, eukaryotic translation initiation factor 2
- EYFP, enhanced yellow fluorescent protein
- GCN2, general control nonrepressed 2
- GSK-3β, glycogen synthase kinase-3β
- HECT, homologous to E6-AP carboxylterminus
- HRP, horseradish peroxidase
- MEM, minimum essential medium
- Mcl-1
- Mcl-1, myeloid cell leukaemia sequence 1
- Mule, Mcl-1 ubiquitin ligase E3
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- PERK, PKR-like ER kinase
- PEST domain
- SDS–PAGE, sodium dodecyl sulphate–polyacrylamide gel electrophoresis
- TM domain, transmembrane domain
- UV, ultraviolet light
- h, hour
- kD, kilodaltons
- pDNA, plasmid DNA
- β-TrCP, β-transducin repeat-containing protein
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