A Facile Synthesis and Physical Properties of Nano-Sized Dendritic α,ε-Poly(L-lysine)s for the Delivery of Nucleic Acids

2006 ◽  
Vol 6 (11) ◽  
pp. 3532-3538
Author(s):  
Khee Dong Eom ◽  
Jin Sook Kim ◽  
Sun Mi Park ◽  
Myong Soo Kim ◽  
Rina Yu ◽  
...  
Keyword(s):  
Complex Formation ◽  
Nucleic Acids ◽  
Solid Phase ◽  
Polyacrylamide Gel Electrophoresis ◽  
Solid Phase Peptide Synthesis ◽  
Synthesis Method ◽  
Spherical Shape ◽  
Electrophoretic Mobilities ◽  
Lysine Residues

A series of nano-sized dendritic α,ε-poly(L-lysine)s (DPL) were synthesized by the solid-phase peptide synthesis method, using a core ε-peptide structure consisting of eight lysine residues. Surface amines of dendritic α,ε-poly(L-lysine) were characterized by comparing the retention times of a reverse phase HPLC with the electrophoretic mobilities of capillary zone electrophoresis (CZE) and non-denatured polyacrylamide gel electrophoresis (PAGE). The elution times of α,ε-poly(L-lysine) in HPLC were well correlated with the electrophoretic mobilities of CZE and PAGE. The separation was dependent on size, shape of molecule and the number of surface amine. The α,ε-poly(L-lysine) formed a complex with nucleic acids at various charge ratios and the degree of complex formation was size- and structure-dependent. Atomic force microscopy of the complex visualized the size and morphology of α,ε-poly(L-lysine)/DNA complex as a nano-sized spherical shape. The small size in complex formation provides a promise for in vivo therapeutic application of dendritic α,ε-poly(L-lysine)s or their derivatives in the delivery of gene or oligonucleotide.

scholarly journals Design of PSMA ligands with modifications at the inhibitor part: an approach to reduce the salivary gland uptake of radiolabeled PSMA inhibitors?

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Veronika Barbara Felber ◽  
Manuel Amando Valentin ◽  
Hans-Jürgen Wester
Keyword(s):  
Salivary Gland ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
In Vivo Studies ◽  
Tumor Xenograft ◽  
Tumor Uptake ◽  
Lncap Cells ◽  
High Affinity

Abstract Aim To investigate whether modifications of prostate-specific membrane antigen (PSMA)-targeted radiolabeled urea-based inhibitors could reduce salivary gland uptake and thus improve tumor-to-salivary gland ratios, several analogs of a high affinity PSMA ligand were synthesized and evaluated in in vitro and in vivo studies. Methods Binding motifs were synthesized ‘on-resin’ or, when not practicable, in solution. Peptide chain elongations were performed according to optimized standard protocols via solid-phase peptide synthesis. In vitro experiments were performed using PSMA+ LNCaP cells. In vivo studies as well as μSPECT/CT scans were conducted with male LNCaP tumor xenograft-bearing CB17-SCID mice. Results PSMA ligands with A) modifications within the central Zn2+-binding unit, B) proinhibitor motifs and C) substituents & bioisosteres of the P1′-γ-carboxylic acid were synthesized and evaluated. Modifications within the central Zn2+-binding unit of PSMA-10 (Glu-urea-Glu) provided three compounds. Thereof, only natLu-carbamate I (natLu-3) exhibited high affinity (IC50 = 7.1 ± 0.7 nM), but low tumor uptake (5.31 ± 0.94% ID/g, 1 h p.i. and 1.20 ± 0.55% ID/g, 24 h p.i.). All proinhibitor motif-based ligands (three in total) exhibited low binding affinities (> 1 μM), no notable internalization and very low tumor uptake (< 0.50% ID/g). In addition, four compounds with P1′-ɣ-carboxylate substituents were developed and evaluated. Thereof, only tetrazole derivative natLu-11 revealed high affinity (IC50 = 16.4 ± 3.8 nM), but also this inhibitor showed low tumor uptake (3.40 ± 0.63% ID/g, 1 h p.i. and 0.68 ± 0.16% ID/g, 24 h p.i.). Salivary gland uptake in mice remained at an equally low level for all compounds (between 0.02 ± 0.00% ID/g and 0.09 ± 0.03% ID/g), wherefore apparent tumor-to-submandibular gland and tumor-to-parotid gland ratios for the modified peptides were distinctly lower (factor 8–45) than for [177Lu]Lu-PSMA-10 at 24 h p.i. Conclusions The investigated compounds could not compete with the in vivo characteristics of the EuE-based PSMA inhibitor [177Lu]Lu-PSMA-10. Although two derivatives (3 and 11) were found to exhibit high affinities towards LNCaP cells, tumor uptake at 24 h p.i. was considerably low, while uptake in salivary glands remained unaffected. Optimization of the established animal model should be envisaged to enable a clear identification of PSMA-targeting radioligands with improved tumor-to-salivary gland ratios in future studies.

scholarly journals Unique role of the complement receptor CR1 in the degradation of C3b associated with immune complexes.

1982 ◽  
Vol 156 (6) ◽  
pp. 1739-1754 ◽  
Author(s):  
M E Medof ◽  
K Iida ◽  
C Mold ◽  
V Nussenzweig
Keyword(s):  
Monoclonal Antibodies ◽  
Immune Complexes ◽  
Solid Phase ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Alpha Chain ◽  
Sds Page ◽  
High Concentrations ◽  
Polypeptide Chains

The main finding of this paper is that CR1, the membrane receptor for C3b and C4b, together with C3b/C4b-inactivator (I), degrades C3b bound to immune complexes (C3b*). Two fragments are generated: C3c, which is released from the immune complexes, and C3d*. The C3c fragment released from the cell intermediate EAC1423b prepared with 125I-C3 was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and radioautography. It has a 135,000 mol wt and contains disulfide bonded labeled polypeptide chains of 75,000 and 31,000 mol wt, which presumably represent the beta and a fragment of the alpha-chain of C3b*. Silver staining of the SDS-PAGE gels revealed other C3-derived bands with 39-42,000 mol wt. Human erythrocytes + I also cleave C3b* into C3c and C3d*. The activity of the erythrocytes is CR1 mediated because it can be totally inhibited by monoclonal antibodies to CR1. In contrast with these results, I together with the serum protein beta 1H (H) transform EAC1423b into hemolytically inactive EAC1423bi and cleave the alpha' chain of C3b* into fragments of 70,000 and 40,000 mol wt. Small amounts of C3c are also released at relatively high concentrations of H. On a molar basis, the efficiency of CR1 in the generation of C3c and C3d is 10(4)-10(5) greater than H. An additional observation was that C3c could be released by treating EAC1423bi with CR1 + I and that this reaction was also inhibited by monoclonal antibodies to CR1. Therefore, it is likely that CR1 has binding affinity for iC3b and that the degradation of C3b* proceeds as follows: C3b (formula, see text) C3c + C3d*. Taken together, our findings argue that the processing of C3b* in vivo occurs in solid phase, that is, on the surface of cells bearing CR1.

scholarly journals Alpha 2-macroglobulin binds and inhibits activated protein C

Blood ◽  
1991 ◽  
Vol 78 (9) ◽  
pp. 2283-2290 ◽  
Author(s):  
H Hoogendoorn ◽  
CH Toh ◽  
ME Nesheim ◽  
AR Giles
Keyword(s):  
Complex Formation ◽  
Active Site ◽  
Metal Ion ◽  
Protein C ◽  
Binding Protein ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
High Molecular Weight Complex

In previous studies using a nonhuman primate model of Protein C (PC) activation in vivo, immunoblotting showed substantial amounts of activated PC (APC) in a high molecular weight complex with what was presumed to be a previously unrecognized APC binding protein. This APC complex can also be formed in citrated plasma in vitro. It is of low electrophoretic mobility, sodium dodecyl sulfate (SDS) stable, with an apparent Mr of 320 Kd. Its purification from human plasma was accomplished using barium citrate adsorption, sequential polyethylene glycol (PEG) precipitations, diethylaminoethyl sepharose chromatography, AcA-34 gel filtration, and zinc-chelate affinity chromatography. This was monitored by subjecting the fractions to nondenaturing polyacrylamide gel electrophoresis (PAGE), transfer to polyvinylidene-difluoride membranes, and probing with 125I-labeled human APC. The purified APC-binding protein was homogeneous by SDS-PAGE with an Mr of 275 Kd. Its identity as alpha 2-macroglobulin (alpha 2M) was demonstrated immunochemically. Complex formation between alpha 2M and APC was found to be almost completely inhibited by EDTA, but to a lesser extent by citrate. Complex formation could also be prevented by active site inhibition with D-Phenylalanyl-L-Prolyl-L-Arginine- Chloromethyl Ketone (PPACK) or pretreatment of alpha 2M with methylamine. Incubation of APC (33 nmol/L) with alpha 2M (1 mumol/L) resulted in time-dependent inhibition of APC anticoagulant activity when measured using an activated partial thromboplastin time based APC assay. These data show that alpha 2M binds and inhibits APC in vitro and the interaction is both metal-ion and active-site dependent, requiring functionally intact alpha 2M. As the complexes formed in vitro comigrate electrophoretically with those observed in vivo after PC activation, it is suggested that alpha 2M is a physiologically relevant inhibitor involved in the processing of APC in vivo.

scholarly journals Bispecific GRPR-Antagonistic Anti-PSMA/GRPR Heterodimer for PET and SPECT Diagnostic Imaging of Prostate Cancer

Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1371 ◽  
Author(s):  
Bogdan Mitran ◽  
Zohreh Varasteh ◽  
Ayman Abouzayed ◽  
Sara S. Rinne ◽  
Emmi Puuvuori ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Diagnostic Imaging ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Binding Specificity ◽  
Tumor Uptake ◽  
Biodistribution Data ◽  
Positron Emission ◽  
Ic50 Values

Simultaneous targeting of the prostate-specific membrane antigen (PSMA) and gastrin-releasing peptide receptor (GRPR) could improve the diagnostic accuracy in prostate cancer (PCa). The aim of this study was to develop a PSMA/GRPR-targeting bispecific heterodimer for SPECT and positron emission tomography (PET) diagnostic imaging of PCa. The heterodimer NOTA-DUPA-RM26 was produced by manual solid-phase peptide synthesis. NOTA-DUPA-RM26 was labeled with 111In and 68Ga, with yields >98%, and demonstrated a high stability and binding specificity to PSMA and GRPR. IC50 values for natIn-NOTA-DUPA-RM26 were 4 ± 1 nM towards GRPR and 824 ± 230 nM towards PSMA. An in vivo binding specificity 1 h pi of 111In-NOTA-DUPA-RM26 in PC3-PIP-xenografted mice demonstrated partially blockable tumor uptake when co-injected with an excess of PSMA- or GRPR-targeting agents. Simultaneous co-injection of both agents induced pronounced blocking. The biodistribution of 111In-NOTA-DUPA-RM26 and 68Ga-NOTA-DUPA-RM26 revealed fast activity clearance from the blood and normal organs via the kidneys. Tumor uptake exceeded normal organ uptake for both analogs 1 h pi. 68Ga-NOTA-DUPA-RM26 had a significantly lower tumor uptake (8 ± 2%ID/g) compared to 111In-NOTA-DUPA-RM26 (12 ± 2%ID/g) 1 h pi. Tumor-to-organ ratios increased 3 h pi, but decreased 24 h pi, for 111In-NOTA-DUPA-RM26. MicroPET/CT and microSPECT/CT scans confirmed biodistribution data, suggesting that 68Ga-NOTA-DUPA-RM26 and 111In-NOTA-DUPA-RM26 are suitable candidates for the imaging of GRPR and PSMA expression in PCa shortly after administration.

Targeted Chemotherapy for Breast Cancer Using an Intelligent Doxorubicin-Loaded Hexapeptide Hydrogel

2020 ◽  
Vol 16 (6) ◽  
pp. 842-852
Author(s):  
Shiyao Luo ◽  
Ying Zhu ◽  
Yiping Li ◽  
Li Chen ◽  
Shunzhong Lv ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Solid Phase ◽  
Synthesis Method ◽  
High Water ◽  
High Water Content ◽  
Normal Tissues ◽  
Self Assembling ◽  
Peptide Hydrogel

Self-assembling peptide hydrogels have a high water content, good biocompatibility and have become a competitive research object in the fields of tissue engineering, cancer treatment and drug delivery. In our research, a hexapeptide with high pH sensitivity was designed and synthesized by utilizing a solid-phase synthesis method. Under physiological conditions, the peptide could self-assemble into a hydrogel. When it reached the tumor acidic microenvironment, the peptide was degraded and doxorubicin was released to exert its antitumor effect. A series of physicochemical properties were investigated, including gelling ability, secondary structure, micromorphology, rheological properties and drug release studies. The results illustrated that PIDO peptide hydrogel has good pH responsiveness and injectability. In vitro cytotoxicity experiments and in vivo antitumor experiments showed that PIDO peptide hydrogel has a highly effective therapeutic effect on tumor cells and is less toxic to normal tissues. Our research provides a promising option for targeted drug delivery and sustainable release.

scholarly journals Antibacterial Activity and Specificity of the Six Human α-Defensins

2005 ◽  
Vol 49 (1) ◽  
pp. 269-275 ◽  
Author(s):  
Bryan Ericksen ◽  
Zhibin Wu ◽  
Wuyuan Lu ◽  
Robert I. Lehrer
Keyword(s):  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Host Defense Peptides ◽  
Gram Negative ◽  
Relative Potencies ◽  
Lethal Doses

ABSTRACT We developed a kinetic, 96-well turbidimetric procedure that is capable of testing the antimicrobial properties of six human α-defensins concurrently on a single microplate. The defensins were prepared by solid-phase peptide synthesis and tested against gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and gram-negative bacteria (Enterobacter aerogenes and Escherichia coli). Analysis of the growth curves provided virtual lethal doses (vLDs) equivalent to conventional 50% lethal doses (LD50s), LD90s, LD99s, and LD99.9s obtained from colony counts. On the basis of their respective vLD90s and vLD99s, the relative potencies of human myeloid α-defensins against S. aureus were HNP2 > HNP1 > HNP3 > HNP4. In contrast, their relative potencies against E. coli and E. aerogenes were HNP4 > HNP2 > HNP1 = HNP3. HD5 was as effective as HNP2 against S. aureus and as effective as HNP4 against the gram-negative bacteria in our panel. HD6 showed little or no activity against any of the bacteria in our panel, including B. cereus, which was highly susceptible to the other five α-defensins. The assay described provides a quantitative, precise, and economical way to study the antimicrobial activities of host-defense peptides. Its use has clarified the relative potencies of human α-defensins and raised intriguing questions about the in vivo function(s) of HD6.

Synthesis, biological activity and receptor binding affinity of two [8-arginine]vasopressin analogues with inhibitory properties

1988 ◽  
Vol 53 (11) ◽  
pp. 2907-2913 ◽  
Author(s):  
Franciszek Kasprzykowski ◽  
Zbigniew Grzonka ◽  
Jiřina Slaninová ◽  
Tomislav Barth ◽  
Peter Crause ◽  
...  
Keyword(s):  
Biological Activity ◽  
Arginine Vasopressin ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Synthesis Method ◽  
The Other ◽  
Binding Affinities ◽  
Bovine Kidney ◽  
Liver Membranes ◽  
Vasopressin Analogues

Two analogues of arginine-vasopressin: [1-(β-mercapto-β,β-cyclopentamethylenepropionic acid), 2-D-phenylalanine, 7-sarcosine, 8-arginine]vasopressin and [1-(β-mercapto-β,β-cyclopentamethylenepropionic acid), 2-D-phenylalanine, 7-N-methylalanine, 8-arginine]vasopressin were synthesized by solid-phase peptide synthesis method. Both peptides exhibit antioxytocic, antivasopressor and antiglycogenolytic activities, and on the other hand they are weak antidiuretic agonists. The binding affinities of both analogues to oxytocic receptor (guinea pig myometrium membranes) and to hepatic V1 receptor (rat liver membranes) are practically the same as for the parent hormones, whereas the binding affinities to renal V2 receptor (bovine kidney membranes) are 60-90 times lower than for vasopressin.

scholarly journals Evidence that the major degradation product of glucose-dependent insulinotropic polypeptide, GIP(3-42), is a GIP receptor antagonist in vivo

2002 ◽  
Vol 175 (2) ◽  
pp. 525-533 ◽  
Author(s):  
VA Gault ◽  
JC Parker ◽  
P Harriott ◽  
PR Flatt ◽  
FP O'Harte
Keyword(s):  
Insulin Secretion ◽  
Receptor Antagonist ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Chinese Hamster ◽  
Lung Fibroblasts ◽  
Incretin Hormone ◽  
Ionisation Mass Spectrometry ◽  
Gip Receptor

The incretin hormone glucose-dependent insulinotropic polypeptide (GIP) is rapidly degraded in the circulation by dipeptidyl peptidase IV forming the N-terminally truncated peptide GIP(3-42). The present study examined the biological activity of this abundant circulating fragment peptide to establish its possible role in GIP action. Human GIP and GIP(3-42) were synthesised by Fmoc solid-phase peptide synthesis, purified by HPLC and characterised by electrospray ionisation-mass spectrometry. In GIP receptor-transfected Chinese hamster lung fibroblasts, GIP(3-42) dose dependently inhibited GIP-stimulated (10(-7) M) cAMP production (up to 75.4+/-5.4%; P<0.001). In BRIN-BD11 cells, GIP(3-42) was significantly less potent at stimulating insulin secretion (1.9- to 3.2-fold; P<0.001), compared with native GIP and significantly inhibited GIP-stimulated (10(-7) M) insulin secretion with maximal inhibition (48.8+/-6.2%; P<0.001) observed at 10(-7) M. In (ob/ob) mice, administration of GIP(3-42) significantly inhibited GIP-stimulated insulin release (2.1-fold decrease; P<0.001) and exaggerated the glycaemic excursion (1.4-fold; P<0.001) induced by a conjoint glucose load. These data indicate that the N-terminally truncated GIP(3-42) fragment acts as a GIP receptor antagonist, moderating the insulin secreting and metabolic actions of GIP in vivo.

scholarly journals Sintesis Tetrapeptida PADY menggunakan Metode Fasa Padat dan Aktivitas Antioksidannya

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Rani Maharani Ph.D ◽  
Dadan Sumiarsa ◽  
Christina Marpaung ◽  
Achmad Zainuddin ◽  
Ace Tatang Hidayat ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Peptide Synthesis ◽  
1H Nmr ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Synthesis Method ◽  
Antioxidant Assay ◽  
Rp Hplc ◽  
Amur Sturgeon ◽  
Tof Ms

Peptida antioksidan merupakan kelompok peptida yang berperan penting karena dapat menetralkan radikal bebas, sehingga dapat mencegah dan mengobati penyakit kronis. Salah satu senyawa peptida antioksidan alami yang telah ditemukan peneliti sebelumnya adalah senyawa tetrapeptida PAGY (Pro-Ala-Gly-Tyr) yang diisolasi dari gelatin kulit ikan amur sturgeon (Acipenser schrenckii) dan dilaporkan memiliki aktivitas antioksidannya dengan IC50 5.38 mg/mL dalam uji DPPH dan 0,008 mg/mL dalam uji ABTS berturut-turut. Kelompok kami telah berhasil mensintesis PAGY bersama dengan analognya yakni PSGY, PFFY, PAFY, dan PAIY dengan menggunakan metode sintesis peptida fase padat (SPPS). Pengujian aktivitas antioksidan pada senyawa hasil sintesis menunjukkan bahwa PSGY memiliki aktivitas antioksidan lebih baik dari PAGY. Pencarian analog tetrapeptida antioksidan yang lebih baik hingga saat ini masih terus dilakukan. Pada penelitian ini telah berhasil disintesis analog tetrapeptida lainnya PADY (Pro-Ala-Asp-Tyr) dengan metode sintesis peptida fase padat menggunakan strategi Fmoc/t-Bu pada resin 2-klorotritilklorida dilanjutkan dengan pengujian aktivitas antioksidannya. HATU/HOAT digunakan sebagai reagen pengkopling dalam sintesis PADY. Pemurnian krud PADY dilakukan menggunakan RP-HPLC preparatif sehingga diperoleh PADY murni seberat 14.7 mg (12.6%). Penentuan struktur peptida hasil sintesis dianalisis dengan menggunakan spektroskopi 1H-NMR dan TOF-MS. Pada pengujian aktivitas antioksidan dengan metode DPPH, PADY hasil sintesis memberikan nilai IC50 sebesar 1.850 mg/mL, yang mengindikasikan bahwa PADY menunjukkan aktivitas antioksidan yang lebih rendah daripada PAGY hasil sintesis peneliti sebelumnya. Kata kunci: Antioksidan, tetrapeptida, sintesis peptida fase padat. Antioxidant peptide is a class of peptides that play an important in neutralizing free radicals, therefore this compound can be used to prevent and treat chronic diseases. One of the natural antioxidant peptides reported by previous researcher is PAGY (Pro-Ala-Gly-Tyr), which is isolated from amur sturgeon fish (Acipenser schrenckii) gelatin that showed antioxidant activity with IC50 5.38 and 0.008 mg/mL using DPPH and ABTS assay, respectively. Our group has successfully synthesized PAGY, along with its analogues of PSGY, PFFY, PAFY, and PAIY using solid phase peptide synthesis method (SPPS). Antioxidant assay on synthesised compounds showed that PSGY has better antioxidant activity than PAGY. The search on the analogues of the antioxidant tetrapeptide was continued. From this study, a tetrapeptide analogue PADY (Pro-Ala-Asp-Tyr) has been successfully synthesised by solid phase peptide synthesis method with Fmoc/t-Bu strategy on 2-chlorotrityl chloride resin and tested for its antioxidant activity. HATU and HOAt reagents were used as the coupling reagent for the synthesis of PADY. The resulting PADY peptide solid was then purified using preparative RP-HPLC yielding PADY of 14.7 mg (12.6%). Characterisation of the synthesized compound was analysed by  1H-NMR and TOF-MS. On the antioxidant assay using DPPH method, PADY showed IC50 value of 1.850 mg/mLindicating a lower activity than the synthetic PAGY. Keywords: Antioxidant, tetrapeptide, solid phase peptide synthesis (SPPS).

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