International journal of molecular sciences, Feb 3, 2024
Chemotherapy is still one of the main therapeutic approaches in cancer therapy. Nevertheless, its... more 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.
Calpains are intracellular cysteine proteases with several important physiological functions. Cal... more Calpains are intracellular cysteine proteases with several important physiological functions. Calpain inhibitors may be promising tools in the analysis of the function of the enzyme in diseases caused by overexpression/activation. Here, we report on the synthesis, solution conformation, and characterization of novel group of azapeptides whose sequences originate from an efficient m-calpain substrate, TPLKSPPPSPR, described by us earlier and possess varying levels of calpain inhibition. The Lys residue at P 1 position was replaced with azaglycine (NH 2-NH-COOH) and further changes were made as follows: the N-terminal or/and C-terminal were truncated, amino acids were also changed at P 3 , P 2 , P 0 1 , or P 0 2 positions. Our results indicate that the identity of amino acid moieties between P 4 and P 0 5 positions is essential for the inhibitory activity. Only changes at position P 3 (Pro) are tolerated. Azapeptide analogs, described in this communication could be considered as useful set of compounds for elucidation of the enzyme interaction at P and P 0 sites.
Despite the small number of cases, pancreatic cancer is one of the biggest challenges in tumor th... more Despite the small number of cases, pancreatic cancer is one of the biggest challenges in tumor therapy as its treatment is not yet resolved and the expected 5-year survival rate is only 5%. Therefore, innovative solutions for pancreatic cancer are of great importance. Targeted tumor therapy might provide new possibilities in this field. In our research, we focused on finding peptide-based homing molecules and modified their structure to achieve better targeting properties. We compared several peptides that efficiently recognize receptors that are specific for or overexpressed by pancreatic cancer cells. Their structure-effect relationship was determined that can be useful during drug designing in the future. The antitumor effect of Dau=Aoa-GFLG-K(Dau=Aoa) SKAAKN-OH conjugate, which turned out to be the most efficient one during in vitro studies, were analyzed in vivo in female SCID mice. The obtained 30% inhibition, beside the low toxic side effects, might be a good starting point t...
Cell-penetrating peptides (CPPs) are promising delivery vehicles. These short peptides can transp... more Cell-penetrating peptides (CPPs) are promising delivery vehicles. These short peptides can transport wide range of cargos into cells, although their usage has often limitations. One of them is the endosomatic internalisation and thus the vesicular entrapment. Modifications which increases the direct delivery into the cytosol is highly researched area. Among the oligoarginines the longer ones (n > 6) show efficient internalisation and they are well-known members of CPPs. Herein, we describe the modification of tetra- and hexaarginine with (4–((4–(dimethylamino)phenyl)azo)benzoyl) (Dabcyl) group. This chromophore, which is often used in FRET system increased the internalisation of both peptides, and its effect was more outstanding in case of hexaarginine. The modified hexaarginine may enter into cells more effectively than octaarginine, and showed diffuse distribution besides vesicular transport already at low concentration. The attachment of Dabcyl group not only increases the cel...
The Pancreatic Ductal Adenocarcinoma (PDAC) is one of the most aggressive and dangerous cancerous... more 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. Th...
Calpains are intracellular cysteine proteases with important physiological functions. Up- or down... more Calpains are intracellular cysteine proteases with important physiological functions. Up- or downregulation of their expression can be responsible for several diseases, therefore specific calpain inhibitors may be considered as promising candidates for drug discovery. In this paper we describe the synthesis and characterization of a new class of inhibitors derived from the analysis of amino acid preferences in primed and unprimed sites of calpains by incorporation of l- or d-epoxysuccinyl group (Eps). Amino acids for replacement were chosen by considering the substrate preference of calpain 1 and 2 enzymes. The compounds were characterized by RP-HPLC, amino acid analysis and ESI-MS. Selectivity of the compounds was studied by using calpain 1 and 2; and cathepsin B. We have identified five calpain specific inhibitors with different extent of selectivity. Two of these also exhibited isoform selectivity. Compound NH2-Thr-Pro-Leu-(d-Eps)-Thr-Pro-Pro-Pro-Ser-NH2 proved to be a calpain 2 enzyme inhibitor with at least 11.8-fold selectivity, while compound NH2-Thr-Pro-Leu-(l-Eps)-Ser-Pro-Pro-Pro-Ser-NH2 possesses calpain 1 enzyme inhibition with at least 4-fold selectivity. The results of molecular modeling calculations suggest that the orientation of the bound inhibitor in the substrate binding cleft is markedly dependent on the stereochemistry of the epoxysuccinyl group.
Calpains are intracellular cysteine proteases with several important physiological functions. Cal... more Calpains are intracellular cysteine proteases with several important physiological functions. Calpain inhibitors may be promising tools in the analysis of the function of the enzyme in diseases caused by overexpression/activation. Here, we report on the synthesis, solution conformation, and characterization of novel group of azapeptides whose sequences originate from an efficient m-calpain substrate, TPLKSPPPSPR, described by us earlier and possess varying levels of calpain inhibition. The Lys residue at P1 position was replaced with azaglycine (NH2 -NH-COOH) and further changes were made as follows: the N-terminal or/and C-terminal were truncated, amino acids were also changed at P3, P2, P'1, or P'2 positions. Our results indicate that the identity of amino acid moieties between P4 and P'5 positions is essential for the inhibitory activity. Only changes at position P3 (Pro) are tolerated. Azapeptide analogs, described in this communication could be considered as useful set of compounds for elucidation of the enzyme interaction at P and P' sites.
International journal of molecular sciences, Feb 3, 2024
Chemotherapy is still one of the main therapeutic approaches in cancer therapy. Nevertheless, its... more 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.
Calpains are intracellular cysteine proteases with several important physiological functions. Cal... more Calpains are intracellular cysteine proteases with several important physiological functions. Calpain inhibitors may be promising tools in the analysis of the function of the enzyme in diseases caused by overexpression/activation. Here, we report on the synthesis, solution conformation, and characterization of novel group of azapeptides whose sequences originate from an efficient m-calpain substrate, TPLKSPPPSPR, described by us earlier and possess varying levels of calpain inhibition. The Lys residue at P 1 position was replaced with azaglycine (NH 2-NH-COOH) and further changes were made as follows: the N-terminal or/and C-terminal were truncated, amino acids were also changed at P 3 , P 2 , P 0 1 , or P 0 2 positions. Our results indicate that the identity of amino acid moieties between P 4 and P 0 5 positions is essential for the inhibitory activity. Only changes at position P 3 (Pro) are tolerated. Azapeptide analogs, described in this communication could be considered as useful set of compounds for elucidation of the enzyme interaction at P and P 0 sites.
Despite the small number of cases, pancreatic cancer is one of the biggest challenges in tumor th... more Despite the small number of cases, pancreatic cancer is one of the biggest challenges in tumor therapy as its treatment is not yet resolved and the expected 5-year survival rate is only 5%. Therefore, innovative solutions for pancreatic cancer are of great importance. Targeted tumor therapy might provide new possibilities in this field. In our research, we focused on finding peptide-based homing molecules and modified their structure to achieve better targeting properties. We compared several peptides that efficiently recognize receptors that are specific for or overexpressed by pancreatic cancer cells. Their structure-effect relationship was determined that can be useful during drug designing in the future. The antitumor effect of Dau=Aoa-GFLG-K(Dau=Aoa) SKAAKN-OH conjugate, which turned out to be the most efficient one during in vitro studies, were analyzed in vivo in female SCID mice. The obtained 30% inhibition, beside the low toxic side effects, might be a good starting point t...
Cell-penetrating peptides (CPPs) are promising delivery vehicles. These short peptides can transp... more Cell-penetrating peptides (CPPs) are promising delivery vehicles. These short peptides can transport wide range of cargos into cells, although their usage has often limitations. One of them is the endosomatic internalisation and thus the vesicular entrapment. Modifications which increases the direct delivery into the cytosol is highly researched area. Among the oligoarginines the longer ones (n > 6) show efficient internalisation and they are well-known members of CPPs. Herein, we describe the modification of tetra- and hexaarginine with (4–((4–(dimethylamino)phenyl)azo)benzoyl) (Dabcyl) group. This chromophore, which is often used in FRET system increased the internalisation of both peptides, and its effect was more outstanding in case of hexaarginine. The modified hexaarginine may enter into cells more effectively than octaarginine, and showed diffuse distribution besides vesicular transport already at low concentration. The attachment of Dabcyl group not only increases the cel...
The Pancreatic Ductal Adenocarcinoma (PDAC) is one of the most aggressive and dangerous cancerous... more 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. Th...
Calpains are intracellular cysteine proteases with important physiological functions. Up- or down... more Calpains are intracellular cysteine proteases with important physiological functions. Up- or downregulation of their expression can be responsible for several diseases, therefore specific calpain inhibitors may be considered as promising candidates for drug discovery. In this paper we describe the synthesis and characterization of a new class of inhibitors derived from the analysis of amino acid preferences in primed and unprimed sites of calpains by incorporation of l- or d-epoxysuccinyl group (Eps). Amino acids for replacement were chosen by considering the substrate preference of calpain 1 and 2 enzymes. The compounds were characterized by RP-HPLC, amino acid analysis and ESI-MS. Selectivity of the compounds was studied by using calpain 1 and 2; and cathepsin B. We have identified five calpain specific inhibitors with different extent of selectivity. Two of these also exhibited isoform selectivity. Compound NH2-Thr-Pro-Leu-(d-Eps)-Thr-Pro-Pro-Pro-Ser-NH2 proved to be a calpain 2 enzyme inhibitor with at least 11.8-fold selectivity, while compound NH2-Thr-Pro-Leu-(l-Eps)-Ser-Pro-Pro-Pro-Ser-NH2 possesses calpain 1 enzyme inhibition with at least 4-fold selectivity. The results of molecular modeling calculations suggest that the orientation of the bound inhibitor in the substrate binding cleft is markedly dependent on the stereochemistry of the epoxysuccinyl group.
Calpains are intracellular cysteine proteases with several important physiological functions. Cal... more Calpains are intracellular cysteine proteases with several important physiological functions. Calpain inhibitors may be promising tools in the analysis of the function of the enzyme in diseases caused by overexpression/activation. Here, we report on the synthesis, solution conformation, and characterization of novel group of azapeptides whose sequences originate from an efficient m-calpain substrate, TPLKSPPPSPR, described by us earlier and possess varying levels of calpain inhibition. The Lys residue at P1 position was replaced with azaglycine (NH2 -NH-COOH) and further changes were made as follows: the N-terminal or/and C-terminal were truncated, amino acids were also changed at P3, P2, P'1, or P'2 positions. Our results indicate that the identity of amino acid moieties between P4 and P'5 positions is essential for the inhibitory activity. Only changes at position P3 (Pro) are tolerated. Azapeptide analogs, described in this communication could be considered as useful set of compounds for elucidation of the enzyme interaction at P and P' sites.
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Papers by Levente Dókus