Peptide Carrier Research Articles

Renal Targeting: Peptide-Based Drug Delivery to Proximal Tubule Cells.

Kidney-specific drug targeting is an attractive strategy to reduce unwanted side effects and to enhance drug efficacy within the renal tissue. For this purpose a novel kidney-specific drug carrier was developed. The peptide sequence (KKEEE)3K triggers exceptional renal specificity at high accumulation rates. Micro-PET imaging studies of megalin-deficient mice indicate that the cellular endocytosis of this carrier is mediated by megalin. This assumption is supported by immunohistochemical analysis of FITC-labeled carrier peptide, which exclusively accumulated at the apical side of proximal tubule cells within the renal cortex. Scintigraphic studies of modified ciprofloxacin conjugated to (KKEEE)3K confirmed the excellent drug targeting potential of the peptide carrier. The conjugate accumulated entirely in the kidneys, revealing flawless redirection of ciprofloxacin, a compound that is mainly excreted by the liver. In conclusion, these results suggest the potential of (KKEEE)3K as a promising candidate for kidney-targeted drug delivery to proximal tubule cells.

Targeting of Peptide Cytotoxins to LHRH Receptors For Treatment of Cancer.

Receptors for LHRH (luteinizing hormone-releasing hormone) are expressed in about 80% of human endometrial, ovarian and prostate cancers and are also found in more than 50% of breast cancers including triple negative breast cancers. In the human body, LHRH receptors are found at significant levels in the pituitary and reproductive organs. Other benign tissues or hematopoietic stem cells express only low levels of receptors for LHRH or no receptors. Thus LHRH receptors are promising targets for a receptor- mediated chemotherapy with cytotoxic hybrid molecules. Cytotoxic analogs of LHRH consist of a LHRH agonist, which is used as a carrier peptide and DOX or its derivatives. Cytotoxic analogs of LHRH, AEZS-108 (formerly known as AN-152) and AN-207, exhibit anti-cancer activity in various in vitro and in vivo models of LHRH-receptor positive cancers. In AEZS-108 (zoptarelin DOX) DOX is covalently linked to the LHRH agonist [D-Lys(6)]LHRH. Results of phase I and II clinical studies in patients with breast, endometrial and ovarian cancers demonstrated good anticancer activity with moderate toxic side effects and without any sign of cardiotoxicity so far. AEZS-108 is also being evaluated in phase I/II studies in castration resistant prostate cancer and metastatic bladder cancer. Because of the very promising phase II results in endometrial cancer, a multinational, multicenter phase III study of this malignancy has been initiated and is currently recruiting patients.

Inter-molecular β-sheet structure facilitates lung-targeting siRNA delivery.

Size-dependent passive targeting based on the characteristics of tissues is a basic mechanism of drug delivery. While the nanometer-sized particles are efficiently captured by the liver and spleen, the micron-sized particles are most likely entrapped within the lung owing to its unique capillary structure and physiological features. To exploit this property in lung-targeting siRNA delivery, we designed and studied a multi-domain peptide named K-β, which was able to form inter-molecular β-sheet structures. Results showed that K-β peptides and siRNAs formed stable complex particles of 60 nm when mixed together. A critical property of such particles was that, after being intravenously injected into mice, they further associated into loose and micron-sized aggregates, and thus effectively entrapped within the capillaries of the lung, leading to a passive accumulation and gene-silencing. The large size aggregates can dissociate or break down by the shear stress generated by blood flow, alleviating the pulmonary embolism. Besides the lung, siRNA enrichment and targeted gene silencing were also observed in the liver. This drug delivery strategy, together with the low toxicity, biodegradability, and programmability of peptide carriers, show great potentials in vivo applications.

Dual-drug RGD conjugates provide enhanced cytotoxicity to melanoma and non-small lung cancer cells.

To enhance the efficacy of targeted drug delivery, four new peptide-ligand conjugates were synthesized, each consisting of a cyclic RGDfK penta-peptide loaded with two anticancer drugs. The drug release profiles in different media of these new compounds and their cytotoxic activity against melanoma and non-small lung cancer cell lines were evaluated and compared with those of their singly loaded analogs. The cyclic RGDfK penta-peptide was selected as a targeting moiety because of its high affinity and selectivity to the αv β3 integrin receptor, which is frequently over-expressed in various types of cancer cells. The peptide's core was modified at the side chain of its Lys residue by coupling it with a sixth amino acid (AA) - either Lys (5a) or Ser (5b) (Lys/Ser splitter), resulting in two functional sites which enabled the loading of two therapeutic equivalents onto a single targeting carrier. Using Lys as a splitter resulted in two primary amines. Consequently, conjugates 1a and 1b were synthesized by coupling of 2 Chlorambucils (CLBs) or 2 Camptothecins (CPTs), respectively, to the primary amines of 5a. Conjugate 1c was synthesized from 5b by loading two equivalents of CLB on the amine and the hydroxyl of the Ser splitter, resulting in a homodimeric system with two distinct conjugation sites - amide and ester. The heterodimeric conjugate 1d of CLB and CPT was synthesized by loading each one of the primary amines of 5a with two different drugs - CLB and CPT. The doubling of drug equivalents loaded onto the targeting peptide correlated with enhanced cytotoxic efficacy of the conjugates towards cancer cells. The versatility of chemical linkages of the drugs to the peptides resulted in conjugates with different drug release profiles. Molecular dynamics simulations performed on conjugate 1d demonstrated that this compound occupies a conformational space similar to the bio-active conformation of an integrin-bound cyclic RGD peptide reference peptide (c(RGDf(NMe)V). The modified position in 1d (relative to the reference peptide) points away from the integrin, leading us to hypothesize that this peptide binds the integrin in a manner similar to that of the reference peptide thereby fulfilling a crucial requirement for targeted delivery. The strategy of dual drug loading on a single peptide carrier, gives rise to drugs with different mechanisms of action and release profiles, thus substantially increasing the efficacy of selective killing of tumor cells and while reducing the risk of the development of drug resistance. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 160-171, 2016.

Tragacanth as an oral peptide and protein delivery carrier: Characterization and mucoadhesion

Biopolymers such as tragacanth, an anionic polysaccharide gum, can be alternative polymeric carrier for physiologically important peptides and proteins. Characterization of tragacanth is thus essential for providing a foundation for possible applications. Rheological studies colloidal solution of tragacanth at pH 3, 5 or 7 were carried out by means of steady shear and small amplitude oscillatory measurements. Tragacanth mucoadhesivity was also analyzed using an applicable rheological method and compared to chitosan, alginate and PVP. The particle size and zeta potential were measured by a zetasizer. Thermal properties of solutions were obtained using a differential scanning calorimetry. The solution exhibited shear-thinning characteristics. The value of the storage modulus (G′) and the loss modulus (G″) increased with an increase in angular frequency (Ω). In all cases, loss modulus values were higher than storage values (G″>G′) and viscous character was, therefore, dominant. Tragacanth and alginate showed a good mucoadhesion. Tragacanth upon dispersion created particles of a submicron size with a negative zeta potential (−7.98 to −11.92mV). These properties were pH dependant resulting in acid gel formation at pH 3.5. Tragacanth has thus a potential to be used as an excipient for peptide/protein delivery.

Non-invasive topical delivery of plasmid DNA to the skin using a peptide carrier

Topical delivery to skin is an essential step in non-invasive application of nucleic acid therapeutics for cutaneous disorders. The barrier posed by different layers of the skin – stratum corneum on top followed by the viable epidermis below – makes it extremely challenging for large hydrophilic molecules like nucleic acids to efficiently enter the uncompromised skin. We report an amphipathic peptide Mgpe9 (CRRLRHLRHHYRRRWHRFRC) that can penetrate the uncompromised skin, enter skin cells and deliver plasmid DNA efficiently as nanocomplexes in vitro and in vivo without any additional physical or chemical interventions prevalent currently. We observe efficient gene expression up to the highly proliferating basal layer of the skin without observable adverse reactions or toxic effects after delivery of reporter plasmids. The entry mechanism of nanocomplexes possibly involves reversible modulation of junction proteins accompanied by transient changes in skin structure. This peptide holds potential to be used as an efficient transporter of therapeutic nucleic acids to the skin.

Cell-Penetrating Peptides as Carriers for Oral Delivery of Biopharmaceuticals.

Oral delivery of biopharmaceuticals, for example peptides and proteins, constitutes a great challenge in drug delivery due to their low chemical stability and poor permeation across the intestinal mucosa, to a large extent limiting the mode of administration to injections, which is not favouring patient compliance. Nevertheless, cell-penetrating peptides (CPPs) have shown promising potential as carriers to overcome the epithelium, and this minireview highlights recent knowledge gained within the field of CPP-mediated transepithelial delivery of therapeutic peptides and proteins from the intestine. Two approaches may be pursued: co-administration of the carrier and therapeutic peptide in the form of complexes obtained by simple bulk mixing, or administration of covalent conjugates demanding more advanced production methodologies. These formulation approaches have their pros and cons, and which is to be preferred depends on the physicochemical properties of both the specific CPP and the specific cargo. In addition to the physical epithelial barrier, a metabolic barrier must be overcome in order to obtain CPP-mediated delivery of a cargo drug from the intestine, and a number of strategies have been employed to delay enzymatic degradation of the CPP. The mechanisms by which CPPs translocate across membranes are not fully understood, but possibly involve endocytosis as well as direct translocation, and the CPP-mediated transepithelial delivery of cargo drugs thus likely involves similar mechanisms for the initial membrane interaction and translocation. However, the mechanisms responsible for transcytosis of the cargo drug, if taken up by an endocytic mechanism, or direct translocation across the epithelium are so far not known.

Antibody-coupled siRNA as an efficient method for in vivo mRNA knockdown.

Knockdown of genes by RNA interference (RNAi) in vitro requires methods of transfection or transduction, both of which have limited impact in vivo. As a virus-free approach, we chemically coupled cell surface receptors internalizing antibodies to the short interfering RNA (siRNA) carrier peptide protamine using the bispecific cross-linker sulfo-SMCC (sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate). First, protamine was conjugated amino-terminally to sulfo-SMCC, and then this conjugate was coupled via cysteine residues to the IgG backbone to carry siRNA. This complex can efficiently find, bind and internalize into receptor-positive cells in vitro and in vivo, which can be checked by flow cytometry, fluorescence microscopy and western blotting. This method obtains results similar to those of siRNA targeting molecules engineered by genetic fusions between receptor-binding and siRNA carrier units, with the advantage of using readily available purified proteins without the need for engineering, expression and purification of respective constructs. The procedure for coupling the complex takes ∼ 2 d, and the functional assays take ∼ 2 weeks.

Tumor-selective peptide-carrier delivery of Paclitaxel increases in vivo activity of the drug.

Taxanes are highly effective chemotherapeutic drugs against proliferating cancer and an established option in the standard treatment of ovarian and breast cancer. However, treatment with paclitaxel is associated with severe side effects, including sensory axonal neuropathy, and its poor solubility in water complicates its formulation. In this paper we report the in vitro and in vivo activity of a new form of paclitaxel, modified for conjugation with a tumor-selective tetrabranched peptide carrier (NT4). NT4 selectively targets tumor cells by binding to membrane sulfated glycosaminoglycans (GAG) and to endocytic receptors, like LRP1 and LRP6, which are established tumor markers. Biological activity of NT4-paclitaxel was tested in vitro on MDA-MB 231 and SKOV-3 cell lines, representing breast and ovarian cancer, respectively, and in vivo in an orthotopic mouse model of human breast cancer. Using in vivo bioluminescence imaging, we found that conjugation of paclitaxel with the NT4 peptide led to increased therapeutic activity of the drug in vivo. NT4-paclitaxel induced tumor regression, whereas treatment with unconjugated paclitaxel only produced a reduction in tumor growth. Moreover, unlike paclitaxel, NT4-paclitaxel is very hydrophilic, which may improve its pharmacokinetic profile and allow the use of less toxic dilution buffers, further decreasing its general chemotherapic toxicity.

Sequential In Vitro Cyclization by Cytochrome P450 Enzymes of Glycopeptide Antibiotic Precursors Bearing the X‐Domain from Nonribosomal Peptide Biosynthesis

The biosynthesis of the glycopeptide antibiotics, which include vancomycin and teicoplanin, relies on the interplay between the peptide-producing non-ribosomal peptide synthetase (NRPS) and Cytochrome P450 enzymes (P450s) that catalyze side-chain crosslinking of the peptide. We demonstrate that sequential in vitro P450-catalyzed cyclization of peptide substrates is enabled by the use of an NRPS peptide carrier protein (PCP)-X di-domain as a P450 recruitment platform. This study reveals that whilst the precursor peptide sequence influences the installation of the second crosslink by the P450 OxyAtei , activity is not restricted to the native teicoplanin peptide. Initial peptide cyclization is possible with teicoplanin and vancomycin OxyB homologues, and the latter displays excellent activity with all substrate combinations tested. By using non-natural X-domain substrates, bicyclization of hexapeptides was also shown, which demonstrates the utility of this method for the cyclization of varied peptide substrates in vitro.

Sequential In Vitro Cyclization by Cytochrome P450 Enzymes of Glycopeptide Antibiotic Precursors Bearing the X‐Domain from Nonribosomal Peptide Biosynthesis

AbstractThe biosynthesis of the glycopeptide antibiotics, which include vancomycin and teicoplanin, relies on the interplay between the peptide‐producing non‐ribosomal peptide synthetase (NRPS) and Cytochrome P450 enzymes (P450s) that catalyze side‐chain crosslinking of the peptide. We demonstrate that sequential in vitro P450‐catalyzed cyclization of peptide substrates is enabled by the use of an NRPS peptide carrier protein (PCP)‐X di‐domain as a P450 recruitment platform. This study reveals that whilst the precursor peptide sequence influences the installation of the second crosslink by the P450 OxyAtei, activity is not restricted to the native teicoplanin peptide. Initial peptide cyclization is possible with teicoplanin and vancomycin OxyB homologues, and the latter displays excellent activity with all substrate combinations tested. By using non‐natural X‐domain substrates, bicyclization of hexapeptides was also shown, which demonstrates the utility of this method for the cyclization of varied peptide substrates in vitro.

DDEL-18EVIDENCE THE TRANSPORTER PEPTIDE, K16ApoE, TRANSIENTLY OPENS THE BLOOD-BRAIN BARRIER TO ALLOW PASSAGE OF MOLECULES TO THE BRAIN

BACKGROUND: Novel avenues for delivering drugs to the brain are needed for the treatment of patients with brain cancer. We have created a carrier peptide, K16ApoE, which is modeled along apolipoprotein E-low density lipoprotein receptor (ApoE-LDLR) interactions that allows passage of both large and small molecules across the blood-brain barrier (BBB). The mechanism underlying K16ApoE-mediated brain targeting of molecules remains to be established. We provide evidence that K16ApoE creates transient opening of the BBB allowing passage of molecules to the brain. METHODS: Trans-endothelial electrical resistance (TEER) and sucrose permeability were determined using an in vitro BBB model consisted of endothelial cells for the ‘lumen’ side and astrocytes on the ‘brain’ side. Brain delivery of Evans Blue and cisplatin was achieved by administration of K16ApoE followed by injection of the compounds through the femoral vein. Brain uptake of cisplatin was quantified by atomic absorption spectrometry. RESULTS: Control in vitro BBB model (no K16ApoE) showed high TEER and a sucrose impermeable ‘brain’ side, indicating intact ‘barrier’. However, the presence of K16ApoE produced rapid and reversible decrease (∼3-fold) as well as an increase in sucrose permeability, suggesting transient opening of endothelial tight junctions. This observation was then evaluated further by delivering Evans Blue and cisplatin with and without K16ApoE. No Evans Blue brain uptake occurred when the dye was injected alone. However, mice brains were visibly blue when the dye was injected after injection of K16ApoE. Brain uptake of cisplatin was ∼40-fold greater with K16ApoE than without, amounting to brain uptake of ∼1.5% of the injected dose of cisplatin. SIGNIFICANCE: The results suggest K16ApoE renders the BBB transiently permeable, which may be utilized for brain targeting of chemotherapy drugs. Thus, the method may offer a simple avenue for pre-clinical evaluation of drugs against brain cancer and potentially other neurological disorders.

Antisense peptide nucleic acid–peptide conjugates for functional analyses of genes in Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the most common and clinically important pathogens because of its resistance to a wide variety of antibiotics. A number of treatments of P. aeruginosa have been developed, but there is still no definitive one. Antisense drugs have a great potential to treat multidrug-resistant P. aeruginosa because this technology, in principle, can inhibit the expression of any essential genes. Nucleic Acid Ther.2012, 22, 323 reported that peptide nucleic acid (PNA) antisenses conjugated to the carrier peptide (RXR)4 and targeted to ftsZ and acpP (essential genes) had antibacterial activity in P. aeruginosa. However, growth inhibition was also found with peptide–PNA antisense conjugates of mismatched sequences (negative controls), and hence there remains a possibility for considerable enhancement of basal level activity due to the general toxicity. To assess the true potential of peptide–PNA conjugates, we measured sequence-dependent knockdown of the (RXR)4–PNA conjugates by using a scrambled sequence as a negative control. In addition, we evaluated (RXR)4–PNA antisenses against three other essential genes (lepB, lptD and mraY) and a non-essential gene (PA1303), and confirmed that multiple sequences targeting only the essential genes showed antimicrobial activity in P. aeruginosa PAO1 cells. We also conducted a rescue experiment and confirmed that the antimicrobial activity of anti-mraY antisenses was an on-target effect, not due to general toxicity. These findings indicate that the (RXR)4–PNA antisense should be a useful tool for target validation of a specific gene and could be a therapeutic platform capable of targeting a variety of genes in P. aeruginosa.

Fusogenic-oligoarginine peptide-mediated silencing of the CIP2A oncogene suppresses oral cancer tumor growth in vivo

Intracellular delivery and endosomal escape of functional small interfering RNAs (siRNAs) remain major barriers limiting the clinical translation of RNA interference (RNAi)-based therapeutics. Recently, we demonstrated that a cell-penetrating endosome-disruptive peptide we synthesized, termed 599, enhanced the intracellular delivery and bioavailability of siRNAs designed to target the CIP2A oncoprotein (siCIP2A) into oral cancer cells and consequently inhibited oral cancer cell invasiveness and anchorage-independent growth in vitro. Thus, to further assess the therapeutic potential of the 599 peptide in mediating RNAi-based therapeutics for oral cancer and its prospective applicability in clinical settings, the objective of the current study was to determine whether intratumoral dosing of the 599 peptide–siCIP2A complex could induce silencing of CIP2A and consequently impair tumor growth using a xenograft oral cancer mouse model. Our results demonstrate that the 599 peptide is able to protect siRNAs from degradation by serum and ribonucleases in vitro and upon intratumoral injection in vivo, confirming the stability of the 599 peptide–siRNA complex and its potential for therapeutic utility. Moreover, 599 peptide-mediated delivery of siCIP2A to tumor tissue induces CIP2A silencing without any associated toxicity, consequently resulting in reduction of the mitotic index and significant inhibition of tumor growth. Together, these data suggest that the 599 peptide carrier is a clinically effective mediator of RNAi-based cancer therapeutics.

ID: 205: A new RNA-based adjuvant enhances virus-specific vaccine responses by locally activating DC and inducing IFN-I responses TLR- and RLH-dependently

Among new adjuvants conferring a TH1-shift, RNAdjuvant® consisting of non-coding RNA complexed with a cationic carrier peptide is a promising candidate. Upon RNAdjuvant® treatment, bone marrow-derived myeloid dendritic cells (BM-mDC) and plasmacytoid DC (BM-pDC) showed Toll-like receptor (TLR)7-dependent IFN-I induction and upregulation of CD69 and CD86. This result was verified by the ex vivo analysis of splenic DC. Immunization of mice with seasonal influenza vaccines plus RNAdjuvant® significantly enhanced vaccine-induced influenza-specific IgG responses. In particular, IgG2b and IgG2c antibody subclasses were elevated, indicating a TH1-biased immune response. RNAdjuvant® mediated enhancement of antibody responses was conferred by concomitant TLR- and RIG-I-like helicase (RLH)-dependent signaling. Thus, upon administration of RNAdjuvant® two different signaling pathways were induced, explaining the strong immunoenhancing effect of RNAdjuvant®. Notably, upon intramuscular (i.m.) injection of RNAdjuvant® IFN-I induction and CD69 upregulation on DC were only detectable in draining, but not in non-draining lymph nodes. Furthermore, transient lymphopenia as a sensitive readout of serum cytokine responses was only detected upon intravenous (i.v.), but not upon i.m., injection of RNAdjuvant®. These observations indicated that i.m. administration of RNAdjuvant® induced primarily local effects. In conclusion, RNAdjuvant® is a novel efficacious immune enhancer that augments vaccine-induced TH1 responses in a MyD88- and Cardif-dependent manner by triggering strictly local effects. Thus, RNAdjuvant® holds promise to be a particularly well tolerable new adjuvant also in humans.

The Use of Affinity Tags to Overcome Obstacles in Recombinant Protein Expression and Purification.

Research and industrial demands for recombinant proteins continue to increase over time for their broad applications in structural and functional studies and as therapeutic agents. These applications often require large quantities of recombinant protein at desirable purity, which highlights the importance of developing and improving production approaches that provide high level expression and readily achievable purity of recombinant protein. E. coli is the most widely used host for the expression of a diverse range of proteins at low cost. However, there are common pitfalls that can severely limit the expression of exogenous proteins, such as stability, low solubility and toxicity to the host cell. To overcome these obstacles, one strategy that has found to be promising is the use of affinity tags or carrier peptide to aid in the folding of the target protein, increase solubility, lower toxicity and increase the level of expression. In the meantime, the tags and fusion proteins can be designed to facilitate affinity purification. Since the fusion protein may not exhibit the native conformation of the target protein, various strategies have been developed to remove the tag during or after purification to avoid potential complications in structural and functional studies and to obtain native biological activities. Despite extensive research and rapid development along these lines, there are unsolved problems and imperfect applications. This focused review compares and contrasts various strategies that employ affinity tags to improve bacterial expression and to facilitate purification of recombinant proteins. The pros and cons of the approaches are discussed for more effective applications and new directions of future improvement.

Abstract LB-106: Fusogenic-oligoarginine peptide-mediated silencing of the CIP2A oncogene suppresses oral cancer tumor growth in vivo

Abstract Intracellular delivery and endosomal escape of functional small interfering RNAs (siRNAs) remain major barriers limiting the clinical translation of RNA interference (RNAi)-based therapeutics. Recently, we demonstrated that a endosome-disruptive peptide we synthesized termed, 599, could enhance the intracellular delivery and bioavailability of siRNAs designed to target the CIP2A oncoprotein (siCIP2A) into oral cancer cells and consequently inhibit oral cancer cell invasiveness and anchorage-independent growth in vitro. Thus, to further assess the therapeutic potential of the 599 peptide in mediating RNAi-based therapeutics for oral cancer and its prospective applicability in clinical settings, the objective of the current study was to determine whether intratumoral dosing of the 599+siCIP2A complex could induce silencing of CIP2A and consequently impair tumor growth using a xenograft oral cancer mouse model. Our results demonstrated that the 599 peptide was able to protect siRNAs from degradation by serum and ribonucleases in vitro, confirming the stability of the 599+siRNA complex and its potential for in vivo utility. Moreover, 599 peptide-mediated delivery of siCIP2A to tumor tissue induced CIP2A silencing without any associated toxicity, consequently resulting in reduction of the mitotic index and significant inhibition of tumor growth. Together, these data suggest that the 599 peptide carrier could be a clinically effective mediator of RNAi-based cancer therapeutics. Citation Format: Angela Alexander-Bryant, Anca Dumitriu, Christopher Attaway, Hong Yu, Andrew Jakymiw. Fusogenic-oligoarginine peptide-mediated silencing of the CIP2A oncogene suppresses oral cancer tumor growth in vivo. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-106. doi:10.1158/1538-7445.AM2015-LB-106

Towards Selective Light‐Activated RuII‐Based Prodrug Candidates

AbstractPhotoactivated chemotherapy (PACT) relies on the use of a drug and light to cause cell death. Unlike photodynamic therapy (PDT), its mechanism of action is independent of the presence of oxygen in tissues. This approach is therefore also effective for tumours characterized by hypoxic conditions. Herein we present the use of three novel RuII–polypyridyl complexes derivatized with a light‐sensitive cage and targeting peptides as selective PACT agents. Light irradiation allowed the selective release of the cytotoxic compounds from the molecular cages in living cells. Further selectivity was conferred on the system by a peptide carrier (i.e., bombesin), which targets receptors overexpressed on the membranes of HeLa cells. As expected, this peptide was found to provide an increased uptake of the systems in HeLa cells compared with normal MRC‐5 cells. As a result, for two of the compounds presented in this study, no cyto‐ or phototoxicity was observed in MRC‐5 cells, whereas in HeLa cells, upon light irradiation, IC50 values of 42.2 and 60.0 μM were obtained, which correspond to a two‐fold increase in toxicity.

The efficacy of chimeric vaccines constructed with PEP-1 and Ii-Key linking to a hybrid epitope from heterologous viruses

The heterologous epitope-peptide from different viruses may represent an attractive candidate vaccine. In order to evaluate the role of cell-permeable peptide (PEP-1) and Ii-Key moiety from the invariant chain (Ii) of MHC on the heterologous peptide chimeras, we linked the two vehicles to hybrid epitopes on the VP2 protein (aa197–209) of the infectious bursal disease virus and HN protein (aa345–353) of the Newcastle disease virus. The chimeric vaccines were prepared and injected into mice. The immune effects were measured by indirect ELISA. The results showed that the vehicle(s) could significantly boost immune effects against the heterologous epitope peptide. The Ii-Key-only carrier induced more effective immunological responses, compared with the PEP-1 and Ii-Key hybrid vehicle. The carrier–peptide hybrids all showed strong colocalization with major histocompatibility complex (MHC) class II molecules compared with the epitope-peptide (weakly-binding) after co-transfection into 293T cells. Together, our results lay the groundwork for designing new hybrid vaccines based on Ii-Key and/or PEP-1 peptides.

소수성 항균 펩타이드 전달체로 응용하기 위한 데옥시콜릭산이 결합된 저분자량 수용성 키토산 나노입자의 제조와 특성

소수성 항균 펩타이드 전달체로 응용하기 위한 데옥시콜릭산이 결합된 저분자량 수용성 키토산 나노입자의 제조와 특성