Določanje estrogenega agonističnega in antagonističnega delovanja analogov bisfenola A in S

Rebov, Taja (author), Peterlin Mašič, Lucija (mentor)

V zadnjih letih smo prišli do spoznanja, da smo izpostavljeni motilcem endokrinega sistema, ki se lahko zaradi svoje podobnosti v telesu prisotnim hormonom, vežejo na endokrine receptorje. Tako lahko delujejo bodisi kot agonisti ali kot antagonisti danih receptorjev. Eden izmed njih je bisfenol A, sintetična spojina, ki se uporablja v proizvodnji polikarbonatne plastike, epoksi smol in termalnega papirja. V človeško telo najpogosteje prehaja preko hrane ali plastičnih posod za hrano, vode, preko stika s termalnim papirjem, prisoten pa je tudi v zraku, predvsem kot posledica sežiganja plastike. Zaradi povečane prevalence različnih z endokrinim sistemom povezanih bolezni in ugotovljene povezave z bisfenolom A, se je njegova uporaba opazno zmanjšala. Zamenjali so ga njegovi analogi, ki so slabo raziskani. Namen našega dela je bil ugotoviti smotrnost zamenjave bisfenola A z njegovimi analogi z vidika učinka na estrogene receptorje. Testirali smo 13 analogov, preverili njihovo citotoksičnost z resazurinom in agonistični ter antagonistični učinek na estrogene receptorje α, ki smo ga izvedli na celicah hERα-HeLa-9903 z luciferaznim testom. Sledili smo smernicam OECD 455 in za vrednotenje agonističnega oziroma antagonističnega učinka izračunali parametre IC30, IC50, PC10, PC50, EC50 in RPCMAX. Citotoksični so bili bisfenoli C, G, PH pri koncentraciji 25 µM, zato teh koncentraciji nismo testirali za agonistični in antagonistični učinek. Kot agonisti estrogenskega receptorja α so se izkazali bisfenoli G, AP, B, E, C, S, dinitrobisfenol A, tetraklorobisfenol A in DD70. Kot antagonisti so se izkazali bisfenoli G, PH, dinitrobisfenol A, TGSH, BPSIP in DD70. Prišli smo do zaključka, da sta za vezavo v receptor ključni fenolni OH skupini na določeni razdalji in da estradiol najbolje oponašajo analogi, ki imajo substitucijo na C atomu med obema fenolnima obročema. Pri določanju antagonističnega učinka smo imeli več težav, odstopanja med meritvami so bila večja in posledično je bilo tudi več neskladij z že objavljeno literaturo, ki je je bilo na voljo manj, saj gre za slabše raziskan vidik vezave na estrogene receptorje. Za boljše razumevanje vpliva analogov bisfenola A na estrogenske receptorje bi bile potrebne nadaljnje preiskave. Vrednotili smo le aktivnost na estrogenske receptorje α, za bolj celovito sliko o varnosti analogov bisfenola A, bi bilo potrebno preveriti tudi učinke analogov na ostale estrogenske receptorje.

• Language: Slovenian
• Keywords: bisfenol A, BPA, bisfenoli, estrogeni receptor, motilci endokrinega sistema, MES
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2022
• PID: 20.500.12556/RUL-141566
• Publication date in RUL: 01.10.2022

Secondary language

• Language: English
• Title: Evaluation of estrogenic agonist and antagonist activity of bisphenol a and s analogues

Abstract

In recent years, we have become aware of our exposure to endocrine disrupting chemicals (EDCs) that can bind to specific receptors because of their similarity to endogenous hormones. They can act as either agonists or antagonists of said receptors. One of the endocrine disrupting chemicals is bisphenol A, a synthetic chemical used in polycarbonate plastic, epoxy resins, and thermal paper. Exposure to bisphenol A occurs primarily through food, plastic food containers, water, thermal paper, and the air as plastic is burnt. Due to the increased incidence of various endocrine system disorders and their association with bisphenol A, it is being used less and less. It is replaced by its analogues, which are poorly studied. The aim of our work was to investigate the usefulness of replacing bisphenol A with its analogues in terms of its effect on estrogen receptors. We tested 13 analogues for cytotoxicity with resazurin, for agonistic and antagonistic effect on estrogen receptors α, which was performed on hERα-HeLa-9903 cells using the luciferase enzyme assay. We followed the OECD 455 protocol and calculated IC30, PC10, PC50, EC50, and RPCMAX to determine their agonistic or antagonistic effects. Bisphenols C, G, PH showed cytotoxicity at concentrations of 25 µM, so they were excluded from further evaluation. We concluded that bisphenols G, AP, B, E, C, S, dinitrobisphenol A, tetrachlorobisphenol A and DD70 showed agonistic effects on estrogen receptor α. On the other hand, bisphenols G, PH, dinitrobisphenol A, TGSH, BPSIP, and DD70 showed antagonistic effects. We had no major problems with the evaluation of agonistic effects, and our results were comparable to those previously published. We concluded that the phenolic OH groups with the correct spacing are crucial for binding to the receptor and that the analogues with a substitution at the C atom of the bridge best mimic estradiol. However, the evaluation of antagonistic effects was more problematic, and the variation between our results was larger, so our results were not necessarily in agreement with those of other research groups. We propose to investigate the effects of bisphenol A analogues on estrogen receptor α further to understand it better. We only studied the effects on estrogen receptors α; for more accurate results, other estrogen receptors should also be studied.

• Keywords: bisphenol A, BPA, bisphenols, estrogen receptor, endocrine disrupting chemicals, EDC