Biodegradable Polymers for Gene Delivery Thomas, T J; Tajmir-Riahi, Heidar-Ali; Pillai, C K S
Molecules (Basel, Switzerland),
10/2019, Letnik:
24, Številka:
20
Journal Article
Recenzirano
Odprti dostop
The cellular transport process of DNA is hampered by cell membrane barriers, and hence, a delivery vehicle is essential for realizing the potential benefits of gene therapy to combat a variety of ...genetic diseases. Virus-based vehicles are effective, although immunogenicity, toxicity and cancer formation are among the major limitations of this approach. Cationic polymers, such as polyethyleneimine are capable of condensing DNA to nanoparticles and facilitate gene delivery. Lack of biodegradation of polymeric gene delivery vehicles poses significant toxicity because of the accumulation of polymers in the tissue. Many attempts have been made to develop biodegradable polymers for gene delivery by modifying existing polymers and/or using natural biodegradable polymers. This review summarizes mechanistic aspects of gene delivery and the development of biodegradable polymers for gene delivery.
•The important role of NH2 group in DOX was studied in drug–DNA interaction.•Both DOX and FDOX intercalated into DNA duplex.•DOX induced major DNA structural changes, while FDOX did not alter DNA ...conformation.•The structural changes induced by DOX were related to its anticancer activity.•NH2 group caused major differences between DOX– and FDOX–DNA interactions.
The intercalation of antitumor drug doxorubicin (DOX) and its analogue N-(trifluoroacetyl) doxorubicin (FDOX) with DNA duplex was investigated, using FTIR, CD, fluorescence spectroscopic methods and molecular modeling. Both DOX and FDOX were intercalated into DNA duplex with the free binding energy of −4.99kcal for DOX–DNA and −4.92kcal for FDOX–DNA adducts and the presence of H-bonding network between doxorubicin NH2 group and cytosine-19. Spectroscopic results showed FDOX forms more stable complexes than DOX with KDOX-DNA=2.5(±0.5)×104M−1 and KFDOX-DNA=3.4(±0.7)×104M−1. The number of drug molecules bound per DNA (n) was 1.2 for DOX and 0.6 for FDOX. Major alterations of DNA structure were observed by DOX intercalation with a partial B to A-DNA transition, while no DNA conformational changes occurred upon FDOX interaction. This study further confirms the importance of unmodified daunosamine amino group for optimal interactions with DNA. The results of in vitro MTT assay carried out on SKC01 colon carcinoma corroborate the observed DNA interactions. Such DNA structural changes can be related to doxorubicin antitumor activity, which prevents DNA duplication.
We located the binding sites of doxorubicin (DOX) and N-(trifluoroacetyl) doxorubicin (FDOX) with bovine serum albumin (BSA) and human serum albumins (HSA) at physiological conditions, using constant ...protein concentration and various drug contents. FTIR, CD and fluorescence spectroscopic methods as well as molecular modeling were used to analyse drug binding sites, the binding constant and the effect of drug complexation on BSA and HSA stability and conformations. Structural analysis showed that doxorubicin and N-(trifluoroacetyl) doxorubicin bind strongly to BSA and HSA via hydrophilic and hydrophobic contacts with overall binding constants of K(DOX-BSA) = 7.8 (± 0.7) × 10(3) M(-1), K(FDOX-BSA) = 4.8 (± 0.5)× 10(3) M(-1) and K(DOX-HSA) = 1.1 (± 0.3)× 10(4) M(-1), K(FDOX-HSA) = 8.3 (± 0.6)× 10(3) M(-1). The number of bound drug molecules per protein is 1.5 (DOX-BSA), 1.3 (FDOX-BSA) 1.5 (DOX-HSA), 0.9 (FDOX-HSA) in these drug-protein complexes. Docking studies showed the participation of several amino acids in drug-protein complexation, which stabilized by H-bonding systems. The order of drug-protein binding is DOX-HSA > FDOX-HSA > DOX-BSA > FDOX>BSA. Drug complexation alters protein conformation by a major reduction of α-helix from 63% (free BSA) to 47-44% (drug-complex) and 57% (free HSA) to 51-40% (drug-complex) inducing a partial protein destabilization. Doxorubicin and its derivative can be transported by BSA and HSA in vitro.
Past studies present contradictory results regarding the effect of milk on the antioxidant capacities of teas, possibly because of the different methods used. Here, we re-address the question by ...using three complementary assays, ABTS
+ free radical scavenging, voltammetry, and lipid peroxidation inhibition, to estimate how milk affects the antioxidant capacities of green, Darjeeling, and English breakfast teas. We observed that milk decreased the antioxidant capacities of Darjeeling (−8.3%), green (−6.0%), and English breakfast (−19.6%) teas, estimated with the ABTS
+ method. These inhibitions were four times larger using voltammetry. In contrast, milk enhanced the chain-breaking antioxidant capacity of teas in the lipid peroxidation method by 19%, 12%, and 10%, for green, English breakfast, and Darjeeling teas, respectively. Therefore, milk can have dual effects on the tea antioxidant capacity, an inhibitory effect for reactions occurring in solution or at a solid–liquid interface and an enhancing effect for those in oil-in-water emulsion. The mechanisms responsible for these different milk–tea interactions are discussed.
► Tea polyphenols weakly bind to both α- and β-caseins. ► The order of binding increases as the number of OH group increased. ► β-Casein forms stronger complexes with tea polyphenols than α-casein. ► ...Polyphenol–casein interaction is more hydrophobic than hydrophilic. ► Polyphenol binding alters casein secondary structure, leading to protein unfolding.
The interaction of α- and β-caseins with tea polyphenols (+)-catechin (C), (−)-epicatechin (EC), (−)-epigallocatechin (EGC) and (−)-epigallocatechin gallate (EGCG) was examined at a molecular level, using FTIR, UV–visible, CD and fluorescence spectroscopic methods as well as molecular modelling. The polyphenol binding mode, the binding constant and the effects of polyphenol complexation on casein stability and conformation were determined. Structural analysis showed that polyphenols bind casein via both hydrophilic and hydrophobic interactions with overall binding constants of KC–α-cas=1.8 (±0.8)×103M−1, KEC–α-cas=1.8 (±0.6)×103M−1, KEGC–α-cas=2.4 (±1.1)×103M−1 and KEGCG–α-cas=7.4 (±0.4)×103M−1, KC–β-cas=2.9 (±0.3)×103M−1, KEC–β-cas=2.5 (±0.6)×103M−1, KEGC–β-cas=3.5 (±0.7)×103M−1 and KEGCG–β-cas=1.59 (±0.2)×104M−1. The number of polyphenol bound per protein molecule (n) was 1.1 (C), 0.9 (EC), 1.1 (EGC), 1.5 (EGCG) for α-casien and 1.0 (C), 1.0 (EC), 1.1 (EGC) and 1.5 (EGCG) for β-casein. Structural modelling showed the participation of several amino acid residues in polyphenol–protein complexation with extended H-bonding network. Casein conformation was altered by polyphenol with a major reduction of α-helix and β-sheet and increase of random coil and turn structure suggesting further protein unfolding. These data can be used to explain the mechanism by which the antioxidant activity of tea compounds is affected by the addition of milk.
There are several lipid binding sites on serum albumins. The aim of this study was to examine the binding of bovine serum albumin (BSA) to cholesterol (Chol), ...1,2-dioleoyl-3-(trimethylammonium)propane (DOTAP), (dioctadecyldimethyl)ammonium bromide (DDAB), and dioleoylphosphatidylethanolamine (DOPE), at physiological conditions, using constant protein concentration and various lipid contents. Fourier transform infrared (FTIR), circular dichroism (CD) and fluorescence spectroscopic methods were used to analyze the lipid binding mode, the binding constant, and the effects of lipid complexation on BSA stability and conformation. Structural analysis showed that lipids bind BSA via both hydrophilic and hydrophobic contacts with overall binding constants of K Chol = (1.12 ± 0.40) × 103 M−1, K DDAB = (1.50 ± 0.50) × 103 M−1, K DOTAP = (2.45 ± 0.80) × 103 M−1, and K DOPE = (1.35 ± 0.60) × 103 M−1. The numbers of bound lipid (n) were 1.1 (cholesterol), 1.28 (DDAB), 1.02 (DOPE), and 1.21 (DOTAP) in these lipid−BSA complexes. DDAB and DOTAP induced major alterations of BSA conformation, causing a partial protein unfolding, while cholesterol and DOPE stabilized protein secondary structure.
Lead is a potent environmental toxin that has accumulated above its natural level as a result of human activity. Pb cation shows major affinity towards protein complexation and it has been used as ...modulator of protein-membrane interactions. We located the binding sites of Pb(II) with human serum (HSA) and bovine serum albumins (BSA) at physiological conditions, using constant protein concentration and various Pb contents. FTIR, UV-visible, CD, fluorescence and X-ray photoelectron spectroscopic (XPS) methods were used to analyse Pb binding sites, the binding constant and the effect of metal ion complexation on HSA and BSA stability and conformations. Structural analysis showed that Pb binds strongly to HSA and BSA via hydrophilic contacts with overall binding constants of K(Pb-HSA) = 8.2 (±0.8)×10(4) M(-1) and K(Pb-BSA) = 7.5 (±0.7)×10(4) M(-1). The number of bound Pb cation per protein is 0.7 per HSA and BSA complexes. XPS located the binding sites of Pb cation with protein N and O atoms. Pb complexation alters protein conformation by a major reduction of α-helix from 57% (free HSA) to 48% (metal-complex) and 63% (free BSA) to 52% (metal-complex) inducing a partial protein destabilization.
Biodegradable chitosan of different sizes were used to encapsulate antitumor drug doxorubicin (Dox) and its N-(trifluoroacetyl) doxorubicin (FDox) analogue. The complexation of Dox and FDox with ...chitosan 15, 100, and 200 KD was investigated in aqueous solution, using FTIR, fluorescence spectroscopic methods, and molecular modeling. The structural analysis showed that Dox and FDox bind chitosan via both hydrophilic and hydrophobic contacts with overall binding constants of K Dox‑ch‑15 = 8.4 (±0.6) × 103 M–1, K Dox‑ch‑100 = 2.2 (±0.3) × 105 M–1, K Dox‑ch‑200 = 3.7 (±0.5) × 104 M–1, K FDox‑ch‑15 = 5.5 (±0.5) × 103 M–1, K FDox‑ch‑100 = 6.8 (±0.6) × 104 M–1, and K FDox‑ch‑200 = 2.9 (±0.5) × 104 M–1, with the number of drug molecules bound per chitosan (n) ranging from 1.2 to 0.5. The order of binding is ch-100 > 200 > 15 KD, with stronger complexes formed with Dox than FDox. The molecular modeling showed the participation of polymer charged NH2 residues with drug OH and NH2 groups in the drug–polymer adducts. The presence of the hydrogen-bonding system in FDox-chitosan adducts stabilizes the drug–polymer complexation, with the free binding energy of −3.89 kcal/mol for Dox and −3.76 kcal/mol for FDox complexes. The results show chitosan 100 KD is a more suitable carrier for Dox and FDox delivery.
Biogenic polyamines, such as putrescine, spermidine, and spermine are small organic polycations involved in numerous diverse
biological processes. These compounds play an important role in nucleic ...acid function due to their binding to DNA and RNA.
It has been shown that biogenic polyamines cause DNA condensation and aggregation similar to that of inorganic cobalt(III)hexamine
cation, which has the ability to induce DNA conformational changes. However, the nature of the polyamine·DNA binding at the
molecular level is not clearly established and is the subject of much controversy. In the present study the effects of spermine,
spermidine, putrescine, and cobalt(III)hexamine on the solution structure of calf-thymus DNA were investigated using affinity
capillary electrophoresis, Fourier transform infrared, and circular dichroism spectroscopic methods. At low polycation concentrations,
putrescine binds preferentially through the minor and major grooves of double strand DNA, whereas spermine, spermidine, and
cobalt(III)hexamine bind to the major groove. At high polycation concentrations, putrescine interaction with the bases is
weak, whereas strong base binding occurred for spermidine in the major and minor grooves of DNA duplex. However, major groove
binding is preferred by spermine and cobalt(III)hexamine cations. Electrostatic attractions between polycation and the backbone
phosphate group were also observed. No major alterations of B-DNA were observed for biogenic polyamines, whereas cobalt(III)hexamine
induced a partial B â A transition. DNA condensation was also observed for cobalt(III)hexamine cation, whereas organic polyamines
induced duplex stabilization. The binding constants calculated for biogenic polyamines are K Spm = 2.3 Ã 10 5 m -1 , K Spd = 1.4 Ã 10 5 m -1 , and K Put = 1.02 Ã 10 5 m -1 . Two binding constants have been found for cobalt(III)hexamine with K 1 = 1.8 Ã 10 5 m -1 and K 2 = 9.2 Ã 10 4 m -1 . The Hill coefficients indicate a positive cooperativity binding for biogenic polyamines and a negative cooperativity for
cobalt(III)hexamine.
Human serum albumin (HSA) is a major transporter for delivering several endogenous compounds including fatty acids in vivo. Even though HSA is the primary target of fatty acid binding, the effects of ...cationic lipid on protein stability and conformation have not been investigated. The aim of this study was to examine the interaction of human serum albumin (HSA) with helper lipidscholesterol (Chol) and dioleoylphosphatidylethanolamine (DOPE)and with cationic lipidsdioctadecyldimethylammonium bromide (DDAB) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), at physiological conditions, using constant protein concentration and various lipid contents. Fourier transform infrared (FTIR), circular dichroism (CD), and fluorescence spectroscopic methods were used to analyze the lipid binding mode, the binding constant, and the effects of lipid interaction on HSA stability and conformation. Structural analysis showed that cholesterol and DOPE (helper lipids) interact mainly with HSA polypeptide polar groups and via hydrophobic moieties. Hydrophobic interactions dominate the binding of cationic lipids to HSA. The number of bound lipids (n) calculated was 1.22 (cholesterol), 1.82 (DDAB), 1.76 (DOPE), and 1.56 (DOTAP). The overall binding constants estimated were K Chol = 2.3 (±0.50) × 103 M−1, K DDAB = 8.9 (±0.95) × 103 M−1, K DOTAP = 9.1 (±0.90) × 103 M−1, and K DOPE = 4.7 (±0.70) × 103 M−1. HSA conformation was stabilized by cholesterol and DOPE with a slight increase of protein α-helical structures, while DOTAP and DDAB induced an important (α → β) transition, suggesting a partial protein unfolding.
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