Drug targeting to decrease cardiotoxicity - determination of the cytotoxic effect of GnRH-based conjugates containing doxorubicin, daunorubicin and methotrexate on human cardiomyocytes and endothelial cells.

Cardiomyopathy induced by the chemotherapeutic agents doxorubicin and daunorubicin is a major limiting factor for their application in cancer therapy. Chemotactic drug targeting potentially increases the tumor selectivity of drugs and decreases their cardiotoxicity. Increased expression of gonadotropin-releasing hormone (GnRH) receptors on the surface of tumor cells has been reported.

Molecular characterization of the β-amyloid(4-10) epitope of plaque specific Aβ antibodies by affinity-mass spectrometry using alanine site mutation.

Alzheimer disease is a neurodegenerative disease affecting an increasing number of patients worldwide. Current therapeutic strategies are directed to molecules capable to block the aggregation of the β-amyloid(1-42) (Aβ) peptide and its shorter naturally occurring peptide fragments into toxic oligomers and amyloid fibrils. Aβ-specific antibodies have been recently developed as powerful antiaggregation tools.

Designer Extracellular Matrix Based on DNA-Peptide Networks Generated by Polymerase Chain Reaction.

Cell proliferation and differentiation in multicellular organisms are partially regulated by signaling from the extracellular matrix. The ability to mimic an extracellular matrix would allow particular cell types to be specifically recognized, which is central to tissue engineering. We present a new functional DNA-based material with cell-adhesion properties.

Improved in vivo antitumor effect of a daunorubicin - GnRH-III bioconjugate modified by apoptosis inducing agent butyric acid on colorectal carcinoma bearing mice.

Compared to classical chemotherapy, peptide-based drug targeting is a promising therapeutic approach for cancer, which can provide increased selectivity and decreased side effects to anticancer drugs. Among various homing devices, gonadotropin-releasing hormone-III (GnRH-III) peptide represents a suitable targeting moiety, in particular in the treatment of hormone independent tumors that highly express GnRH receptors (e.g.

[Studying the tumor growth inhibitory effect of modified GnRH-III-anthracycline bioconjugates in subcutaneous vs. orthotopic models in vivo].

Targeted tumor therapy is a perspective procedure to specifically destroy the cancer tissues with eliminating or at least decreasing the side effects of anticancer drugs. For this purpose the drug molecule is attached to a targeting moiety (e.g.

New insights into coenzyme A interaction with mercury ions provided by mass spectrometric and circular dichroism spectroscopic approaches.

The interaction of coenzyme A (CoA) with mercury ions was investigated using electrospray ionization mass spectrometry and circular dichroism spectroscopy. Our results indicated a 1:1 stoichiometric CoA-Hg complex at physiological pH. Furthermore, the CoA conformation considerably changed in the presence of mercury ions.

Modification of daunorubicin-GnRH-III bioconjugates with oligoethylene glycol derivatives to improve solubility and bioavailability for targeted cancer chemotherapy.

Daunorubicin-GnRH-III bioconjugates have recently been developed as drug delivery systems with potential applications in targeted cancer chemotherapy. In order to improve their biochemical properties, several strategies have been pursued: (1) incorporation of an enzymatic cleavable spacer between the anticancer drug and the peptide-based targeting moiety, (2) peptide modification by short chain fatty acids, or (3) attachment of two anticancer drugs to the same GnRH-III derivative. Although these modifications led to more potent bioconjugates, a decrease in their solubility was observed.

Oxime bond-linked daunorubicin-GnRH-III bioconjugates exert antitumor activity in castration-resistant prostate cancer cells via the type I GnRH receptor.

It is well established that gonadotropin-releasing hormone receptors (GnRH-R) are expressed in different types of cancers, including castration-resistant prostate cancer (CRPC) and mediate the antiproliferative effect of GnRH analogs. Thus, these compounds are employed as targeting moieties to selectively deliver chemotherapeutic agents to cancer cells. GnRH-III, the decapeptide isolated from the sea lamprey brain, has lower potency than GnRH in stimulating gonadotropin secretion, but it exerts antiproliferative effects on many tumors expressing the GnRH-R.

Targeting hormonal signaling pathways in castration resistant prostate cancer.

It is now well established that hormonal pathways are involved in the development of prostate cancer towards the castration resistant (CRPC) stage and can be effective molecular targets for novel treatment strategies. Most CRPC are sensitive to androgens and this can be due to the intratumoral production of androgens, androgen receptor (AR) amplification/ mutations and epigenetic modifications of AR expression/signaling. Based on these observations, potent agents targeting the AR axis were developed: 1) inhibitors of CYP17 (a key enzyme in the production of androgens), such as abiraterone and orteronel; 2) AR antagonists that bind to AR and impair AR activation, such as enzalutamide and ARN-509.

Protein expression profile of HT-29 human colon cancer cells after treatment with a cytotoxic daunorubicin-GnRH-III derivative bioconjugate.

Targeted delivery of chemotherapeutic agents is a new approach for the treatment of cancer, which provides increased selectivity and decreased systemic toxicity. We have recently developed a promising drug delivery system, in which the anticancer drug daunorubicin (Dau) was attached via oxime bond to a gonadotropin-releasing hormone-III (GnRH-III) derivative used as a targeting moiety (Glp-His-Trp-Lys(Ac)-His-Asp-Trp-Lys(Da  = Aoa)-Pro-Gly-NH2; Glp = pyroglutamic acid, Ac = acetyl; Aoa = aminooxyacetyl). This bioconjugate exerted in vitro cytostatic/cytotoxic effect on human breast, prostate and colon cancer cells, as well as significant in vivo tumor growth inhibitory effect on colon carcinoma bearing mice.

Increased levels of antigen-bound β-amyloid autoantibodies in serum and cerebrospinal fluid of Alzheimer's disease patients.

Recent studies have suggested a protective role of physiological β-amyloid autoantibodies (Aβ-autoantibodies) in Alzheimer's disease (AD). However, the determination of both free and dissociated Aβ-autoantibodies in serum hitherto has yielded inconsistent results regarding their function and possible biomarker value. Here we report the application of a new sandwich enzyme-linked immunosorbent assay (ELISA) for the determination of antigen-bound Aβ-autoantibodies (intact Aβ-IgG immune complexes) in serum and cerebrospinal fluid (CSF) of a total number of 112 AD patients and age- and gender-matched control subjects.

Synthesis, enzymatic stability and in vitro cytostatic effect of Daunorubicin-GnRH-III derivative dimers.

Bioconjugates containing chemotherapeutic agents attached to peptide hormones, such as gonadotropin-releasing hormone (GnRH), are developed as drug delivery systems for targeted cancer chemotherapy. We report here the synthesis and biochemical characterization of disulfide bond-linked dimeric bioconjugates in which daunorubicin was coupled via an oxime linkage to aminooxyacetylated GnRH-III ([Glp-His-Trp-Ser-His-Asp-Trp-Lys(DauAoa-Cys)-Pro-Gly-NH2]2; where Glp is pyroglutamic acid and Aoa is aminooxyacetyl) and its derivatives modified in position four by N-Me-Ser and Lys(Ac). The in vitro stability/degradation of the bioconjugates was determined in human serum, as well as in the presence of rat liver lysosomal homogenate and digestive enzymes.

Gonadotropin-releasing hormone receptors as molecular therapeutic targets in prostate cancer: Current options and emerging strategies.

Prostate cancer is androgen-dependent in its early stages and androgen deprivation therapy represents the most effective first-line therapeutic approach. However, after an initial remission, prostate cancer progresses towards the castration resistant prostate cancer (CRPC) stage, with increased malignancy and resistance to conventional chemotherapy. Pituitary gonadotropin-releasing hormone receptors (GnRH-Rs) represent the most effective molecular target for the treatment of steroid-dependent prostate cancer.

Epitope structure and binding affinity of single chain llama anti-β-amyloid antibodies revealed by proteolytic excision affinity-mass spectrometry.

ß-Amyloid (Aß) immunotherapy has become a promising strategy for reducing the level of Aß in brain. New immunological approaches have been recently proposed for rapid, early diagnosis, and molecular treatment of neurodegenerative diseases related to Alzheimer's Disease (AD). The combination of proteolytic epitope excision and extraction and mass spectrometry using digestion with various proteases has been shown to be an efficient tool for the identification and molecular characterization of antigenic determinants.

lGnRH-III -- a promising candidate for anticancer drug development.

Lamprey gonadotropin-releasing hormone-III (lGnRH-III; Glp-His-Trp-Ser-His-Asp-Trp-Lys-Pro-Gly-NH2), a native isoform of human GnRH (GnRH-I), was initially isolated from the brain of the sea lamprey (Petromyzon marinus). It is a weak GnRH agonist, which exerts a direct antiproliferative effect on cancer cells and has an insignificant LH and FSH releasing potency in mammals. These features reveal the advantages of lGnRH-III and its derivatives for use in cancer therapy.

Antigen-bound and free β-amyloid autoantibodies in serum of healthy adults.

Physiological β-amyloid autoantibodies (Aβ-autoantibodies) are currently investigated as potential diagnostic and therapeutic tools for Alzheimer's disease (AD). In previous studies, their determination in serum and cerebrospinal fluid (CSF) using indirect ELISA has provided controversial results, which may be due to the presence of preformed Aβ antigen-antibody immune complexes. Based on the epitope specificity of the Aβ-autoantibodies, recently elucidated in our laboratory, we developed (a) a sandwich ELISA for the determination of circulating Aβ-IgG immune complexes and (b) an indirect ELISA for the determination of free Aβ-autoantibodies.

Enhanced cellular uptake and in vitro antitumor activity of short-chain fatty acid acylated daunorubicin-GnRH-III bioconjugates.

Here we report on the synthesis and biochemical characterization (enzymatic stability, cellular uptake, in vitro antitumor activity, membrane interaction and GnRH-receptor binding affinity) of novel short-chain fatty acid (SCFA) acylated daunorubicin-GnRH-III bioconjugates, which may serve as drug delivery systems for targeted cancer chemotherapy. Ser in position 4 of GnRH-III was replaced by Lys, followed by the acylation of its ε-amino group with various fatty acids. SCFAs are potentially chemoprotective agents by suppressing the growth of cancer cells and therefore may enhance the antitumor activity of the bioconjugates.

Interaction structure of the complex between neuroprotective factor humanin and Alzheimer's β-amyloid peptide revealed by affinity mass spectrometry and molecular modeling.

Humanin (HN) is a linear 24-aa peptide recently detected in human Alzheimer's disease (AD) brain. HN specifically inhibits neuronal cell death in vitro induced by ß-amyloid (Aß) peptides and by amyloid precursor protein and its gene mutations in familial AD, thereby representing a potential therapeutic lead structure for AD; however, its molecular mechanism of action is not well understood. We report here the identification of the binding epitopes between HN and Aß(1-40) and characterization of the interaction structure through a molecular modeling study.

GnRH-III based multifunctional drug delivery systems containing daunorubicin and methotrexate.

Here we report on the design, synthesis and biochemical characterization of multifunctional bioconjugates containing two chemotherapeutic agents, daunorubicin and methotrexate, coupled to the GnRH-III decapeptide, which served as a targeting moiety. This represents a possible approach to increase the receptor mediated tumor targeting and consequently the cytostatic effect of anticancer drug-peptide bioconjugates. The multifunctional bioconjugates were prepared according to two drug design approaches recently developed by our group.

A new daunomycin-peptide conjugate: synthesis, characterization and the effect on the protein expression profile of HL-60 cells in vitro.

Daunomycin (Dau) is a DNA-binding antineoplastic agent in the treatment of various types of cancer, such as osteosarcomas and acute myeloid leukemia. One approach to improve its selectivity and to decrease the side effects is the conjugation of Dau with oligopeptide carriers, which might alter the drug uptake and intracellular fate. Here, we report on the synthesis, characterization, and in vitro biological properties of a novel conjugate in which Dau is attached, via an oxime bond, to one of the cancer specific small peptides (LTVSPWY) selected from a random phage peptide library.

In-vivo antitumour effect of daunorubicin-GnRH-III derivative conjugates on colon carcinoma-bearing mice.

Targeted cancer chemotherapy is a novel approach developed for the specific delivery of anticancer drugs. Tumour targeting can be achieved by combining a chemotherapeutic agent with a targeting moiety that recognizes tumour-specific or highly expressed receptors on cancer cells. We used the gonadotropin-releasing hormone-III (GnRH-III) as a targeting moiety to which the chemotherapeutic agent daunorubicin (Dau) was attached through an oxime bond either directly or by inserting a GFLG tetrapeptide spacer.

Anthracycline-GnRH derivative bioconjugates with different linkages: synthesis, in vitro drug release and cytostatic effect.

To increase the selectivity and consequently to minimize the side effects of chemotherapeutic agents, receptor mediated tumor targeting approaches have been developed. In the present work, various anthracycline-GnRH derivative bioconjugates were synthesized with the aim of investigating the influence of (i) different anthracycline anticancer drugs, (ii) different linkages between the targeting moiety and the anticancer drug, and (iii) different targeting moieties (e.g.

Enhanced enzymatic stability and antitumor activity of daunorubicin-GnRH-III bioconjugates modified in position 4.

Here, we report on the synthesis, enzymatic stability, and antitumor activity of novel bioconjugates containing the chemotherapeutic agent daunorubicin attached through an oxime bond to various gonadotropin-releasing hormone-III (GnRH-III) derivatives. In order to increase the enzymatic stability of the bioconjugates (in particular against chymotrypsin), (4)Ser was replaced by N-Me-Ser or Lys(Ac). A compound in which (4)Lys was not acetylated was also prepared, with the aim of investigating the influence of the free ε-amino group on the biochemical properties.

Design, synthesis, in vitro stability and cytostatic effect of multifunctional anticancer drug-bioconjugates containing GnRH-III as a targeting moiety.

Bioconjugates containing the GnRH-III hormone decapeptide as a targeting moiety are able to deliver chemotherapeutic agents specifically to cancer cells expressing GnRH receptors, thereby increasing their local efficacy while limiting the peripheral toxicity. However, the number of GnRH receptors on cancer cells is limited and they desensitize under continuous hormone treatment. A possible approach to increase the receptor mediated tumor targeting and consequently the cytostatic effect of the bioconjugates would be the attachment of more than one chemotherapeutic agent to one GnRH-III molecule.

In vitro degradation and antitumor activity of oxime bond-linked daunorubicin-GnRH-III bioconjugates and DNA-binding properties of daunorubicin-amino acid metabolites.

Bioconjugates with receptor-mediated tumor-targeting functions and carrying cytotoxic agents should enable the specific delivery of chemotherapeutics to malignant tissues, thus increasing their local efficacy while limiting the peripheral toxicity. In the present study, gonadotropin-releasing hormone III (GnRH-III; Glp-His-Trp-Ser-His-Asp-Trp-Lys-Pro-Gly-NH(2)) was employed as a targeting moiety to which daunorubicin was attached via oxime bond, either directly or by insertion of a GFLG or YRRL tetrapeptide spacer. The in vitro antitumor activity of the bioconjugates was determined on MCF-7 human breast and HT-29 human colon cancer cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.