Načrtovanje in sinteza derivatov benzojske kisline kot zaviralcev človeške DNA topoizomeraze II

Gogova, Liljana (avtor), Ilaš, Janez (mentor), Skok, Žiga (komentor)

Razvoj novih protirakavih zdravilnih učinkovin je izrednega pomena za javno zdravje. Človeška DNA-topoizomeraza II? predstavlja tarčo protirakavih zdravilnih učinkovin širokega spektra, ki zaradi specifičnega izražanja omogoča usmerjeno ciljanje visoko proliferativnih rakavih celic. Zapleten večstopenjski katalitični cikel DNA-topoizomeraze II? omogoča različne pristope k zaviranju delovanja encima. V klinični uporabi je veliko zdravilnih učinkovin (npr. topoizomerazni strupi) z različnimi mehanizmi delovanja na katalitični cikel encima, vendar težavo povzročajo določeni resni neželeni učinki zdravil. Zaradi tega smo se v okviru te magistrske naloge osredotočili na razvoj novih katalitičnih zaviralcev DNA-topoizomeraze II?, ki se vežejo na ATP-vezavno mesto N-terminalnega dela encima in onemogočijo delovanje katalitičnega cikla. Pri eksperimentalnem delu magistrske naloge smo sintetizirati in ovrednotili serijo novih ATP kompetitivnih zaviralcev DNA-topoizomeraze II?, pirolamidnega strukturnega tipa. Osmim pripravljenim spojinam smo določili rezidualne aktivnosti na DNA topoizomerazi II? pri koncentracijah zaviralca 100 µM in 10 µM. Kot aktivne spojine so se izkazale 10, 19 in 23, ki imajo v strukturi prisotno prosto karboksilno skupino. V primerjavi z etopozidom, ki je bil uporabljen kot pozitivna kontrola, smo spojinam 10, 19 in 23 določili nižje IC50 vrednosti ter tako boljšo zaviralno aktivnost na encimu. Spojine iz serije, ki so imele v strukturi namesto karboksilne skupine metilno estrsko skupino ali sulfonamidno skupino, niso pokazale zaviralnega delovanja na encim. Ovrednotili smo tudi citotoksično delovanje spojin 10, 19 in 23 na celični liniji raka dojke (MCF-7) ter ugotovili, da so testirane spojine neaktivne, kar je v nasprotju z rezultati encimskega testiranja. Razlog za pomanjkanje citotoksičnega delovanja je lahko onemogočen prehod spojin v celice ali aktivno črpanje spojin iz celice. Potrebne so nadaljnje raziskave, da bi ugotovili, kakšen mehanizem je odgovoren za odsotnost citotoksičnega delovanja. V prihodnjem bi bilo smiselno načrtovati in razviti spojine, ki imajo poleg dobre zaviralne aktivnosti na encimu tudi ustrezne fizikalno-kemijske lastnosti, da bi uspešno dosegle tarčo v celicah.

• Jezik: Slovenski jezik
• Ključne besede: DNA-topoizomeraza IIα, protirakave učinkovine, ATP kompetitivni zaviralci, pirolamidi.
• Vrsta gradiva: Magistrsko delo/naloga
• Organizacija: FFA - Fakulteta za farmacijo
• Leto izida: 2019
• PID: 20.500.12556/RUL-109747
• Datum objave v RUL: 07.09.2019

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Design and synthesis of benzoic acid derivatives as inhibitors of human DNA topoisomerase II

Izvleček

The development of new anticancer drugs is of extraordinary importance for public health. Human DNA-topoisomerase II? is a target of a wide spectrum of anticancer active substances, which, due to specific expression, allows targeting of highly proliferative cancer cells. The catalytic cycle of DNA-topoisomerase II? consists of several steps and thus provides different approaches of enzyme inhibition. In clinical use there are many active substances (eg. topoisomerase poisons) with different mechanisms of action on the catalytic enzyme cycle, but with serious side effects as a result of the treatment. For this reason, we focused on development of new catalytic DNA topoisomerase II? inhibitors that bind to the ATP-binding site of the N-terminal part of the enzyme and consequently inhibit the catalytic activity. In the experimental part of the master's thesis, we synthesized and evaluated a series of new ATP competitive DNA topoisomerase II?, which are of pyrrolamide structural type. Residual activities at inhibitor concentration of 100 µM and 10 µM were measured for eight compounds. Compounds 10, 19 and 23 possess a free carboxyl group in the structure and show inhibitory activity on the enzyme. In comparison with etoposide, which was used as a positive control, lower IC50 values were determined for compounds 10, 19 and 23, and thus a better inhibitory activity on the enzyme. Compounds of the series, which had a methyl ester group or a sulphonamide group in the structure instead of the carboxyl group, did not show an inhibitory activity on the enzyme. We also evaluated the cytotoxic activity of the compounds 10, 19 and 23 on the breast cancer cell line (MCF-7) and found that the tested compounds were inactive, which is contrary to the results of enzymatic testing. The cause for the absence of cytotoxic activity can be the compounds' inability to pass into the cells or active pumping of the compounds from the cell. Further research is necessary to find out which mechanism is responsible for the absence of cytotoxic activity. In the future, it would be reasonable to design and develop compounds that, in addition to good inhibitor activity on the enzyme, also have appropriate physicochemical properties in order to successfully reach the target in the cells.

• Ključne besede: DNA-topoisomerase II?, anticancer drugs, ATP competatice inhibitros, pyrrolamides.