Growth and differentiation factor-15: A link between inflammaging and cardiovascular disease.

Age-related disorders are closely linked to the accumulation of senescent cells. The senescence-associated secretory phenotype (SASP) sustains and progresses chronic inflammation, which is involved in cellular and tissue dysfunction. SASP-related growth and differentiation factor-15 (GDF-15) is an immunoregulatory cytokine that is coupled to aging and thus may have a regulatory role in the development and maintenance of atherosclerosis, a major cause of cardiovascular disease (CVD). Although the effects of GDF-15 are tissue-specific and dependent on microenvironmental changes such as inflammation, available data suggest that GDF-15 has a significant role in CVD. Thus, GDF-15 is a promising biomarker and potential therapeutic target for atherosclerotic CVD.

Characterisation of the cell and molecular biological effect of peptide-based daunorubicin conjugates developed for targeting pancreatic adenocarcinoma (PANC-1) cell line.

Pancreatic adenocarcinoma is one of the tumours with the worst prognosis, with a 5-year survival rate of 5-10%. Our aim was to find and optimise peptide-based drug conjugates with daunorubicin (Dau) as the cytotoxic antitumour agent. When conjugated with targeting peptides, the side effect profile and pharmacokinetics of Dau can be improved. The targeting peptide sequences (e.g. GSSEQLYL) we studied were originally selected by phage display. By Ala-scan technique, we identified that position 6 in the parental sequence (Dau=Aoa-LRRY-GSSEQLYL-NH2, ConjA) could be modified without the loss of antitumour activity (Dau=Aoa-LRRY-GSSEQAYL-NH2, Conj03: 14. 9% viability). Our results showed that the incorporation of p-chloro-phenylalanine (Dau=Aoa-LRRY-GSSEQF(pCl)YL-NH2, Conj16) further increased the antitumour potency (10-5 M: 9.7% viability) on pancreatic adenocarcinoma cells (PANC-1). We found that conjugates containing modified GSSEQLYL sequences could be internalised to PANC-1 cells and induce cellular senescence in the short term and subsequent apoptotic cell death. Furthermore, the cardiotoxic effect of Dau was markedly reduced in the form of peptide conjugates. In conclusion, Conj16 had the most effective antitumor activity on PANC-1 cells, which makes this conjugate promising for developing new targeted therapies without cardiotoxic effects.

Oxime-Linked Peptide-Daunomycin Conjugates as Good Tools for Selection of Suitable Homing Devices in Targeted Tumor Therapy: An Overview.

Chemotherapy is still one of the main therapeutic approaches in cancer therapy. Nevertheless, its poor selectivity causes severe toxic side effects that, together with the development of drug resistance in tumor cells, results in a limitation for its application. Tumor-targeted drug delivery is a possible choice to overcome these drawbacks. As well as monoclonal antibodies, peptides are promising targeting moieties for drug delivery. However, the development of peptide-drug conjugates (PDCs) is still a big challenge. The main reason is that the conjugates have to be stable in circulation, but the drug or its active metabolite should be released efficiently in the tumor cells. For this purpose, suitable linker systems are needed that connect the drug molecule with the homing peptide. The applied linker systems are commonly categorized as cleavable and non-cleavable linkers. Both the groups possess advantages and disadvantages that are summarized briefly in this manuscript. Moreover, in this review paper, we highlight the benefit of oxime-linked anthracycline-peptide conjugates in the development of PDCs. For instance, straightforward synthesis as well as a conjugation reaction proceed in excellent yields, and the autofluorescence of anthracyclines provides a good tool to select the appropriate homing peptides. Furthermore, we demonstrate that these conjugates can be used properly in in vivo studies. The results indicate that the oxime-linked PDCs are potential candidates for targeted tumor therapy.

Association of growth and differentiation factor-15 with coronary artery calcium score and ankle-brachial index in a middle-aged and elderly Caucasian population sample free of manifest cardiovascular disease.

Growth and differentiation factor-15 (GDF-15) is a stress-associated cytokine of the transforming growth factor-ß superfamily. The inflammatory and angiogenic effects of GDF-15 in atherosclerosis are controversial, and its correlation with the long asymptomatic phase of the disease is not well understood. Coronary artery calcium score (CACS) and ankle-brachial index (ABI) are sensitive markers of subclinical atherosclerosis. To date, only a few studies have examined the impact of GDF-15 on coronary artery calcification, and the association between GDF-15 and ABI has not been evaluated. Therefore, we aimed to investigate the possible relationship between serum GDF-15 concentrations and CACS and ABI in a Caucasian population sample of middle-aged (35-65 years) and elderly (> 65 years) people. In addition to recording demographic and anthropometric characteristics, atherosclerotic risk factors, and laboratory tests including serum HDL-cholesterol, LDL-cholesterol, hemoglobin A1c (HbA1c), high-sensitivity C-reactive protein, and N-terminal pro-B-type natriuretic peptide (NT-proBNP); GDF-15 level, cardiac computed tomography, and ABI measurements were also performed. A total of 269 asymptomatic individuals (men, n = 125; median age, 61.5 [IQR, 12.7] years) formed the basis of this study. Participants were divided into two groups according to their age (middle-aged, n = 175 and elderly, n = 94). Hypertension and diabetes mellitus were significantly more prevalent and CACS values and HbA1c, NT-proBNP, and GDF-15 levels were significantly higher (all p < 0.001) in the elderly group compared to the middle-aged group. Multivariate ridge regression analysis revealed a significant positive association between GDF-15 and CACS (middle-aged group: ß = 0.072, p = 0.333; elderly group: ß = 0.148, p = 0.003), and between GDF-15 and ABI (middle-aged group: ß = 0.062, p = 0.393; elderly group: ß = 0.088, p = 0.041) only in the elderly group. Our results show that GDF-15 is not only a useful biomarker of inflammation but can also predict early signs of asymptomatic atherosclerosis, especially in elderly people with chronic systemic inflammation associated with aging (inflammaging).

PCSK9, A Promising Novel Target for Age-Related Cardiovascular Dysfunction.

Cardiovascular diseases (CVDs) are the leading cause of death among elderly people. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an important regulator of cholesterol metabolism. Herein, we investigated the role of PCSK9 in age-related CVD. Both in humans and rats, blood PCSK9 level correlated positively with increasing age and the development of cardiovascular dysfunction. Age-related fatty degeneration of liver tissue positively correlated with serum PCSK9 levels in the rat model, while development of age-related nonalcoholic fatty liver disease correlated with cardiovascular functional impairment. Network analysis identified PCSK9 as an important factor in age-associated lipid alterations and it correlated positively with intima-media thickness, a clinical parameter of CVD risk. PCSK9 inhibition with alirocumab effectively reduced the CVD progression in aging rats, suggesting that PCSK9 plays an important role in cardiovascular aging.

Neutrophil-to-Lymphocyte Ratio Is an Independent Risk Factor for Coronary Artery Disease in Central Obesity.

Several inflammatory biomarkers were found to be associated with an increased risk of cardiovascular disease. Neutrophil-to-lymphocyte ratio (NLR) is a marker of subclinical inflammation that increases with the stress response. Visceral adiposity index (VAI) calculated as a combination of anthropometric and metabolic parameters reflects both the extent and function of visceral adipose tissue. Given the association of subclinical inflammation with both obesity and cardiovascular diseases, it is plausible that the inflammation-CVD association is modulated by the amount and function of adipose tissue. Thus, our aim was to examine the association between NLR and coronary artery calcium score (CACS), an intermediate marker of coronary artery disease in asymptomatic patients across VAI tertiles. Methods: Data from 280 asymptomatic participants of a cardiovascular screening program were analysed. In addition to the collection of lifestyle and medical history, a non-contrast cardiac CT scan and laboratory tests were performed on all participants. Multivariate logistic regression was conducted with CACS > 100 as the outcome and with conventional cardiovascular risk factors and NLR, VAI, and NLR by VAI tertile as predictors. Results: We found an interaction between VAI tertiles and NLR; NLR values were similar in the lower VAI tertiles, while they were higher in the CACS > 100 in the 3rd VAI tertile (CACS ≤ 100: 1.94 ± 0.58 vs. CACS > 100: 2.48 ± 1.1, p = 0.008). According to multivariable logistic regression, the interaction between NLR and VAI tertiles remained: NLR was associated with CACS > 100 in the 3rd VAI tertile (OR = 1.67, 95% CI 1.06-2.62, p = 0.03) but not in the lower tertiles even after adjustment for age, sex, smoking, history of hypertension, hyperlipidaemia, and diabetes mellitus, as well as high-sensitivity C-reactive protein. Our findings draw attention to the independent association between subclinical, chronic, systemic inflammation and subclinical coronary disease in obesity.

Prevalence of Sjögren's syndrome in patients with dry mouth in the region of Central Hungary.

OBJECTIVE: One-third of the Hungarian population suffers from xerostomia. Since there is no evidence of the actual prevalence of Sjögren's syndrome (SS) in Hungary, this study aimed to evaluate the same. MATERIALS AND METHODS: Data were collected from the Faculty of Dentistry, Semmelweis University from 2008 to 2015. A diagnosis of SS was established based on the American College of Rheumatology and European League Against Rheumatism criteria. RESULTS: Of the 1076 patients examined with sicca symptoms, 188 patients had confirmed SS. Primary SS (pSS) was diagnosed in 135 patients and secondary SS (sSS) was confirmed in 53 patients. According to the available statistical records of the public health service of Hungary, there were an average of 16 (0.0014%, 5-26) newly diagnosed SS cases in the entire population and 141 SS patient-practitioner consultations (49-232) per 100,000 inhabitants in the country over the past 10 years (based on the past 10 years: 2011-2020). CONCLUSION: Results revealed that approximately 1/5th-1/6th of patients with sicca symptoms have SS, among whom 72% and 285 have pSS and sSS, respectively. Global Hungarian records simultaneously revealed that the number of both new diagnoses and doctor-SS patient encounters has significantly decreased (by 50%) yearly over the last decade.

The use of Trojan-horse drug delivery system in managing periodontitis.

The aim of this review is to evaluate the possibility of delivering a silver-acid complex via a Trojan-horse mechanism for managing periodontits. We theroised that the complex could be an effective treatment option for bacterial inflammatory processes in the oral cavity. Searches were conducted using MEDLINE, Embase, Web of Science Core Collection, and Google Scholar search engines. We also reviewed several reference lists of the included studies or relevant reviews identified by the search. By using Medical Subject Headings (MeSH) terminology, a comprehensive search was performed for the following keywords: silver, folic acid, periodontitis, macrophages, Trojan-horse mechanism, toxicity, and targeting. Using the keywords mentioned earlier, we selected 110 articles and after appropriate elimination the review was written based on 37 papers. Accordingly the we noted that silver isons were an effective approach to kill oral pathogens. Secondly the Trojan-horse mechanism. could be used by macrophages (as the Trojan horse) to deliver silver ions in large quantities to the inflammatory focus to kill the periodontopathogens. The Trojan-horse mechanism has never been described in the field of dentistry before. The proposed novel approach using the principle of Trojan Horse delivery of drugs/chemicals could be used to manage oral inflammatory conditions. This method can be used to supplement regular treatments.

Investigation of the Antitumor Effects of Tamoxifen and Its Ferrocene-Linked Derivatives on Pancreatic and Breast Cancer Cell Lines.

Tamoxifen is a long-known anti-tumor drug, which is the gold standard therapy in estrogen receptor (ER) positive breast cancer patients. According to previous studies, the conjugation of the original tamoxifen molecule with different functional groups can significantly improve its antitumor effect. The purpose of this research was to uncover the molecular mechanisms behind the cytotoxicity of different ferrocene-linked tamoxifen derivates. Tamoxifen and its ferrocene-linked derivatives, T5 and T15 were tested in PANC1, MCF7, and MDA-MB-231 cells, where the incorporation of the ferrocene group improved the cytotoxicity on all cell lines. PANC1, MCF7, and MDA-MB-231 express ERα and GPER1 (G-protein coupled ER 1). However, ERß is only expressed by MCF7 and MDA-MB-231 cells. Tamoxifen is a known agonist of GPER1, a receptor that can promote tumor progression. Analysis of the protein expression profile showed that while being cytotoxic, tamoxifen elevated the levels of different tumor growth-promoting factors (e.g., Bcl-XL, Survivin, EGFR, Cathepsins, chemokines). On the other hand, the ferrocene-linked derivates were able to lower these proteins. Further analysis showed that the ferrocene-linked derivatives significantly elevated the cellular oxidative stress compared to tamoxifen treatment. In conclusion, we were able to find two molecules possessing better cytotoxicity compared to their unmodified parent molecule while also being able to counter the negative effects of the presence of the GPER1 through the ER-independent mechanism of oxidative stress induction.

The effects of mouthwashes in human gingiva epithelial progenitor (HGEPp) cells.

OBJECTIVES: The gingiva epithelium accounts for a significant proportion of the surface around the tooth. An inflammatory reaction occurs in the presence of bacterial biofilm, adhesion is reduced, and the depth of the sulcus gingivalis increases. The most common antiseptic agents in oral rinses are chlorhexidine digluconate (CHX) and cetylpyridinium chloride. We examined long-lasting effects of residual concentrations of eight commercially available rinses. Our main goals were (i) to analyze the effect of different chemical compositions on cell proliferation, (ii) to examine apoptosis, and (iii) cell morphology on human epithelial progenitor cell line (HGEPp). MATERIALS AND METHODS: Cell proliferation was measured in a real-time system (0-48 h) by impedimetry (xCELLigence). Apoptosis was measured with labeled Annexin-V (BD-FACScalibur). RESULTS: Changes in proliferation were measured at certain concentrations: (i) H2O2 proved to be cytotoxic at almost all concentrations; (ii) low concentrations of CHX (0.0001%; 0.0003%) were proliferation inducers, while higher concentrations were cytotoxic; (iii) for ClO2, advantageous proliferative effect was observed over a broad concentration range (0.06-6 ppm). In mouthwashes, additives in the formulation (e.g., allantoin) appeared to influence cellular responses positively. Apoptosis marker assay results suggested a low-level activation by the tested agents. CONCLUSIONS: Mouthwashes and their reference compounds proved to have concentration-dependent cytotoxic effects on human gingival epithelial cells. CLINICAL RELEVANCE: A better understanding of the effects of mouthwashes and their reference compounds is particularly important. These concentration-dependent effects (cytotoxic or proliferation inducing) interfere with human cells physiology while being used in the fight against the pathogenic flora.

Level of advanced oxidation protein products is associated with subclinical atherosclerosis.

BACKGROUND: Oxidative stress is an important factor in the pathomechanism of atherosclerosis. Advanced oxidation protein products (AOPPs) are considered markers of oxidative stress. Thickening of the carotid intima-media layers indicates subclinical atherosclerosis and can be detected by carotid ultrasound. OBJECTIVE: Our aim was to examine the association between carotid intima-media thickness (CIMT) and the level of AOPPs. METHODS: Carotid duplex scans and measurements of AOPPs were performed on 476 participants of a cardiovascular population study. The presence of conventional cardiovascular risk factors was investigated with a questionnaire, physical examination, and laboratory tests. RESULTS: There was a positive correlation between maximum CIMT and the level of AOPPs only in the male population (r = 0.219, p = 0.033). Multivariate analysis has revealed that the association between AOPPs and mean or maximum CIMT was independent of cardiovascular risk factors (OR = 1.458, p = 0.004, and OR = 2.038, p < 0.001). CONCLUSIONS: Among males, the elevated level of AOPPs as a marker of oxidative stress may signal the existence of early atherosclerotic alterations.

Effect of dental antiseptic agents on the viability of human periodontal ligament cells.

OBJECTIVES: We aimed to study whether or not various dental antiseptic agents affect the viability and proliferation of human periodontal ligament cells (PDLCs). MATERIALS AND METHODS: Human PDLCs were isolated from a total of 10 surgically extracted impacted third molars and were.cultured in-vitro. The cells were exposed to commonly used dental antiseptics, including chlorhexidine, cetylpyridinium chloride, triclosan, povidone-iodine and sodium bicarbonate for ultra-short-term (10, 20, 30 sec), short-term (10, 20, 30 min) and long-term (24, 48 h) at various concentrations. Cell morphology was observed with light microscopy. Cell viability was studied with impedimetric real-time xCELLigence and resazurin-based alamarBlue® assays. We used one-way ANOVA with Tukey's and Bonferroni test (p < 0.05) for statistical analysis. RESULTS: Both alamarBlue® and xCELLigence analysis results were in agreement that ultra-short-term contact with cetylpyridinium chloride ≥ 0.01 mg/ml, chlorhexidine ≥ 1 mg/ml, triclosan ≥ 1 mg/ml and povidone-iodine ≥ 1 mg/ml as well as long-term exposure to cetylpyridinium chloride ≥ 0.001 mg/ml, chlorhexidine ≥ 0.01 mg/ml, triclosan ≥ 1 mg/ml, povidone-iodine ≥ 1 mg/ml and sodium bicarbonate ≥ 10 mg/ml was able to reduce the viability of human PDLCs significantly. According to the half-maximal inhibitory concentration (IC50) the rank of cytotoxicity was cetylpyridinium chloride > chlorhexidine > triclosan > povidone-iodine > sodium bicarbonate. CONCLUSIONS: Our findings suggest that the tested antiseptic agents were cytotoxic to human PDLCs at lower than practically applied concentrations in dental interventions.

Folate-Targeted Monodisperse PEG-Based Conjugates Made by Chemo-Enzymatic Methods for Cancer Diagnosis and Treatment.

This paper focuses on preliminary in vitro and in vivo testing of new bivalent folate-targeted PEGylated doxorubicin (DOX) made by modular chemo-enzymatic processes (FA2-dPEG-DOX2). A unique feature is the use of monodisperse PEG (dPEG). The modular approach with enzyme catalysis ensures exclusive γ-conjugation of folic acid, full conversion and selectivity, and no metal catalyst residues. Flow cytometry analysis showed that at 10 µM concentration, both free DOX and FA2-dPEG-DOX2 would be taken up by 99.9% of triple-negative breast cancer cells in 2 h. Intratumoral injection to mice seemed to delay tumor growth more than intravenous delivery. The mouse health status, food, water consumption, and behavior remained unchanged during the observation.

Polyisobutylene-New Opportunities for Medical Applications.

This paper presents the results of the first part of testing a novel electrospun fiber mat based on a unique macromolecule: polyisobutylene (PIB). A PIB-based compound containing zinc oxide (ZnO) was electrospun into self-supporting mats of 203.75 and 295.5 g/m2 that were investigated using a variety of techniques. The results show that the hydrophobic mats are not cytotoxic, resist fibroblast cell adhesion and biofilm formation and are comfortable and easy to breathe through for use as a mask. The mats show great promise for personal protective equipment and other applications.

Chemotaxis in Leishmania (Viannia) braziliensis: Evaluation by the two-chamber capillary assay.

Chemotactic responses play a significant role during Leishmania (V.) braziliensis differentiation through its life cycle and during infection. The aim of this description has been to portray the modified "two-chamber capillary chemotaxis assay" as a technique useful for quantitative in vitro evaluation of Leishmania chemotaxis after reviewing the methods described until now to assess chemotaxis in vitro in Leishmania sp. This valued simple and reproducible method convenient for parasite migration determination, was tested by the use of controlled changes in monosaccharide (D-glucose and D-fructose) concentrations as referent ligands. The validation of the method demonstrates that this technique is useful to evaluate the relationship existing between parasite migration towards the monosaccharides and sugar concentration. This means that within specific ranges, parasites attracted by the monosaccharide migrate towards more concentrated solutions and accumulate (higher number of parasites) at that spot. Interestingly, both the time course of the experiment and the osmolality of the solution influence parasite migration capacity. Our validation suggests that this improved methodology quantitatively evaluates taxis of Leishmania towards/against different substances. On the basis of our herein presented data, we conclude that this technique is a novel, rapid and reliable screening method to evaluate chemotaxis in Leishmania.•The two-chamber capillary chemotaxis assay was standardized for Leishmania.•The technique is useful to quantitatively evaluate in vitro chemotaxis in Leishmania.•Parasite migration was characterized by monosaccharide chemical gradients.•This assay is a novel, rapid and reliable screening method to evaluate chemotaxis. Contain between 1 and 3 bullet points highlighting the customization rather than the steps of the procedure.

The Synergistic Activity of Bortezomib and TIC10 against A2058 Melanoma Cells.

Combination antitumor treatments are essential parts of modern tumor therapy as-compared to monotherapies-(i) they are more effective; (ii) the dose of the compounds can be reduced; and (iii) therefore the side effects are improved. Our research group previously demonstrated the antitumor character of bortezomib (BOZ) in A2058 melanoma cells. Unfortunately, dose-related side effects are common during BOZ therapy, which could be prevented by reducing the dose of BOZ. This study aimed to characterize synergistic combinations of BOZ with a TRAIL (TNF-related apoptosis-inducing ligand) -inducing compound (TIC10), where the doses can be cut down but the efficacy is preserved. Endpoint cell viability assays were performed on A2058 cells, and synergism of BOZ and TIC10 was observed after 72 h. Synergism was further validated in a real-time impedimetric assay, and our results showed that BOZ-treated melanoma cells survived the treatment, an effect not registered in the co-treatments. Treatment with the combinations resulted in increased apoptosis, which was not accompanied by enhanced LDH release. Nevertheless, the expression of death receptor 5 (DR5) was increased on the cell surface without transcriptional regulation. In summary, our findings support the theory that the application of BOZ and TIC10 in combination could provide higher efficacy in vitro.

Comparative study of hyperpure chlorine dioxide with two other irrigants regarding the viability of periodontal ligament stem cells.

OBJECTIVES: Periodontal ligament stem cells (PDLSCs) have an underlined significance as their high proliferative capacity and multipotent differentiation provide an important therapeutic potential. The integrity of these cells is frequently disturbed by the routinely used irrigative compounds applied as periodontal or endodontic disinfectants (e.g., hydrogen peroxide (H2O2) and chlorhexidine (CHX)). Our objectives were (i) to monitor the cytotoxic effect of a novel dental irrigative compound, chlorine dioxide (ClO2), compared to two traditional agents (H2O2, CHX) on PDLSCs and (ii) to test whether the aging factor of PDLSC cultures determines cellular responsiveness to the chemicals tested. METHODS: Impedimetry (concentration-response study), WST-1 assays (WST = water soluble tetrazolium salt), and morphology analysis were performed to measure changes in cell viability induced by the 3 disinfectants; immunocytochemistry of stem cell markers (STRO-1, CD90, and CD105) measured the induced mesenchymal characteristics. RESULTS: Cell viability experiments demonstrated that the application of ClO2 does not lead to a significant decrease in viability of PLDSCs in concentrations used to kill microbes. On the contrary, traditional irrigants, H2O2, and CHX are highly toxic on PDLSCs. Aging of PLDSC cultures (passages 3 vs. 7) has characteristic effects on their responsiveness to these agents as the increased expression of mesenchymal stem cell markers turns to decreased. CONCLUSIONS AND CLINICAL RELEVANCE: While the active ingredients of mouthwash (H2O2, CHX) applied in endodontic or periodontitis management have a serious toxic effect on PDLSCs, the novel hyperpure ClO2 is less toxic providing an environment favoring dental structure regenerations during disinfectant interventions.

Alpha-lipoic acid alters the antitumor effect of bortezomib in melanoma cells in vitro.

Bortezomib (BOZ) is a proteasome inhibitor chemotherapeutic agent utilized to treat multiple myeloma and recently offered to cure melanoma. Bortezomib-induced neuropathy is one of the dose-limiting side-effects, which can be treated with antioxidants (e.g. alpha-lipoic acid-ALA and Vitamin B1-vit B1). We hypothesized that these antioxidants may counteract the antitumor activity by disrupting the BOZ-induced pathways (e.g. proteasome inhibition or reactive oxygen species generation). The objectives were: (i) to verify the anti-proliferative effect of BOZ; (ii) to compare the influence of the antioxidants on the antitumor effect of BOZ in melanoma (A2058) and myeloma (U266) cells. At first, the reduction in the anti-proliferative effect of BOZ by ALA was proved in melanoma cells. Analysis of p53 phosphorylation and the cell cycle progression revealed that ALA failed to counteract these effects of BOZ. Nevertheless, a good correlation was found between the inhibition of the anti-proliferative effect, the anti-proteasome activity and the oxidative stress level after the co-treatment with 20 ng/mL BOZ + 100 µg/mL ALA. Downregulation of apoptotic proteins such as HO-1 and Claspin along with the inhibition of the cleavage of Caspase-3 indicated the proteomic background of the altered responsiveness of the melanoma cells exposed to BOZ + ALA. This phenomenon draws attention to the proper application of cancer supportive care to avoid possible interactions.

Amphiphilic drug-peptide-polymer conjugates based on poly(ethylene glycol) and hyperbranched polyglycerol for epidermal growth factor receptor targeting: the effect of conjugate aggregation on in vitro activity.

Numerous peptide-drug conjugates have been developed over the years to enhance the specificity and selectivity of chemotherapeutic agents for tumour cells. In our present work, epidermal growth factor receptor targeting drug-peptide conjugates were prepared using GE11 and D4 peptides. To ensure the drug release, the cathepsin B labile GFLG spacer was incorporated between the targeting peptide and the drug molecule (daunomycin), which significantly increased the hydrophobicity and thereby decreased the water solubility of the conjugates. To overcome the solubility problem, drug-peptide-polymer conjugates with systematic structural variations were prepared, by linking poly(ethylene glycol) (PEG) or a well-defined amino-monofunctional hyperbranched polyglycerol (HbPG) directly or via a pentaglycine spacer to the targeting peptides. All the drug-peptide-polymer conjugates were water-soluble as confirmed by turbidimetric measurements. The results of the in vitro cell viability and cellular uptake measurements on HT-29 human colon adenocarcinoma cells proved that the HbPG and the PEG highly influenced the biological activity. The conjugation of the hydrophilic polymer resulted in the amphiphilic character of the conjugates, which led to self-aggregation and nanoparticle formation that decreased the cellular uptake above a specific aggregation concentration. On the other hand, the hydrodynamic volume and the different polymer chain topology of the linear PEG and the compact hyperbranched HbPG also played an important role in the biological activity. Therefore, in similar systems, the investigation of the colloidal properties is inevitable for the better understanding of the biological activity, which can reveal the structure-activity relationship of amphiphilic drug-peptide-polymer conjugates for efficient tumour targeting.

Phage Display-Based Homing Peptide-Daunomycin Conjugates for Selective Drug Targeting to PANC-1 Pancreatic Cancer.

The Pancreatic Ductal Adenocarcinoma (PDAC) is one of the most aggressive and dangerous cancerous diseases, leading to a high rate of mortality. Therefore, the development of new, more efficient treatment approaches is necessary to cure this illness. Peptide-based drug targeting provides a new tool for this purpose. Previously, a hexapeptide Cys-Lys-Ala-Ala-Lys-Asn (CKAAKN) was applied efficiently as the homing device for drug-loaded nanostructures in PDAC cells. In this research, Cys was replaced by Ser in the sequence and this new SKAAKN targeting moiety was used in conjugates containing daunomycin (Dau). Five different structures were developed and tested. The results indicated that linear versions with one Dau were not effective on PANC-1 cells in vitro; however, branched conjugates with two Dau molecules showed significant antitumor activity. Differences in the antitumor effect of the conjugates could be explained with the different cellular uptake and lysosomal degradation. The most efficient conjugate was Dau=Aoa-GFLG-K(Dau=Aoa)SKAAKN-OH (conjugate 4) that also showed significant tumor growth inhibition on s.c. implanted PANC-1 tumor-bearing mice with negligible side effects. Our novel results suggest that peptide-based drug delivery systems could be a promising tool for the treatment of pancreatic cancers.