Address: Budapest, Pázmány P. sétány 1/A, 401.
The main research topic in our laboratory is the synthesis and biological evaluation of bioconjugates in order to prepare new chemotherapeutically applicable peptide based compounds. Drug conjugation to peptide carrier moiety is used to increase the biological properties of the drugs (e.g. increase the cellular uptake, decrease the side effects, prevention of multidrug resistance, increase the water solubility, etc). On the other hand, proapoptotic peptides are conjugated to peptide carriers to enhance the apoptotic processes in the cancer cells.
Among the drug molecules, antracyclins (daunorubicin, doxorubicin), vinca-alkaloids and folic acid antagonists (methotrexate, pemetrexed) are used for conjugations. The conjugates are built up by different coupling methods (amide, squaric amides, oxime, hydrazone, thioether). The antracyclin containing conjugates can be used without any modification by own fluorescence property not only in the in vitro cytostatic assays but also in the cellular uptake studies. In the case of the other drugs without fluorescence feature; fluorescence labelling is needed for the evaluation of their cellular uptake assays.
The prepared bioconjugates will be applied in two areas of researches. One of them belongs to the cell penetrating peptides (CPPs). Drug molecules are conjugated to these peptides, because they can pass through the cell membranes, and they can deliver the drugs into the cytosol/nucleus. Among the CPPs penetratin and oligoarginine are mostly used in our research. We also make an attempt to synthetize new, short cell penetrating peptidesto minimally decrease the interaction between the drug and the peptide.
The other part of the bioconjugates consists of special peptides to increase the selectivity of the drugs. These carriers are mostly receptor ligands (e.g. GnRH), or cancer cell surface specific ligands (e.g. TMTP-1 peptide). These conjugates have also a proapoptotic peptide unit, which induces apoptotic processes in the cancer cells.
Proapoptotic peptides are originated from different subfamily of proapoptotic proteins; the following ones were selected
i) minimal functional sequence of Bak protein from the Bax subfamily (H-MGQVGRQLAIIGDDINRR-NH2), or
ii) minimal functional sequence of PUMA protein from the BH3-only subfamily (H-IGAQLRRMADDLNAQ-NH2).
Since, the center of apoptotic processes are the mitochondria, targeting of this organelle is a very important role. Therefore the incorporation of the mitochondria targeting sequences into the bioconjugates is essential toward apoptosis.
Our principal aims with these bioconjugates are increasing the apoptosis due to killing the tumor cells.
Peptides are prepared manually by solid phase peptide synthesis using Boc/Bzl or Fmoc/tBu strategy. We have also chance to apply automatic peptide synthetizer (Syro) for the synthesis. Teflon HF apparatus (409. laboratory) is available for detachment of the peptides from the resin in case of Boc/Bzl strategy. The conjugations are mainly carried out in solution phase using different chemical ligation methods. The crude peptides or bioconjugates are purified by RP-HPLC or coloumn chromatography (414. laboratory).
Hudecz F, Banoczi Z, Csik G.: Medium-sized peptides as built in carriers for biologically active compounds. Med Res Rev. 25, 679-736 (2005).
Bánóczi, Z., Tantos, A., Farkas, A., Tompa, P., Friedrich, P., Hudecz, F. Synthesis of cell-penetrating conjugates of calpain activator peptides. Bioconjugate Chem., 18, 130-137 (2007).
Bánóczi, Z., Alexa, A., Farkas, A., Friedrich, P., Hudecz, F. Novel cell-penetrating calpain substrate. Bioconjugate Chem., 19, 1375-1381 (2008)
Szabo, I; Orban, E; Schlosser, G; Hudecz, F; Banoczi, Z Cell-penetrating conjugates of pentaglutamylated methotrexate as potential anticancer drugs against resistant tumor cells. Eur J Med Chem. 115, 361-368 (2016)
Bánóczi Z; Peregi B; Orbán E; Szabó R; Hudecz F: Synthesis of Daunomycin - oligoarginine conjugates and their effect on Human leukemia cells (HL-60). Arkivoc, 2008, Part (III), 140-153 (2007)
Szabó I., Bosze S., Orbán E., Sipos E., Halmos G., Kovács M., Mezo G. Comparative in vitro biological evaluation of daunorubicin containing GnRH-I and GnRH-II conjugates developed for tumor targeting. Journal of Peptide Science, 21 (5), 426-435 (2015).