Title The role of necroptosis in bladder cancer
Title (croatian) Uloga nekroptoze u tumoru mokraćnog mjehura
Author Benedikt Eduard Haupt
Mentor Jelena Korać Prlić (mentor)
Committee member Jasminka Omerović (predsjednik povjerenstva)
Committee member Ivana Marinović Terzić (član povjerenstva)
Committee member Renata Pecotić (član povjerenstva)
Granter University of Split School of Medicine (Immunology and medical genetics) Split
Defense date and country 2020-07-15, Croatia
Scientific / art field, discipline and subdiscipline BIOMEDICINE AND HEALTHCARE Basic Medical Sciences Human Genetics, Genomics and Proteomics
Abstract Objectives: Although great progress has been achieved in terms of bladder cancer management, survival rates for muscle invasive bladder cancer are still dismal, which warrants for the search of new therapeutic approaches. Necroptosis is a programmed type of cell death, whose role has not been fully elucidated in bladder cancer. The objective of this study is to assess the prevalence of necroptosis at different time points during tumor progression and to investigate whether induction or inhibition of necroptosis influences tumor growth.
Methods: This study used two distinct murine bladder cancer models. The first one was an autochthonous BBN-induced bladder cancer model. The second one was a subcutaneous tumor model, made using MB49 cells. Mice with subcutaneous tumors were treated with Necrostatin-1s and Shikonin, two compounds that should have the opposite effects of inhibition and induction of necroptosis, respectively. The tumors were analyzed using gene expression studies, immunohistochemistry and immunoblotting.
Results: It was shown that necroptotic cell death is a late finding during tumor development and that necroptosis and apoptosis occur in separate hotspots in BBN- induced bladder cancers. Necrostatin-1s significantly accelerated tumor growth.
This effect on tumor growth tapered off and was not significantly present by the end of the experiment. Further, Necrostatin-1s did not show the expected inhibitory effect on necroptosis. Shikonin-treated mice had significantly smaller tumor volumes by the end of the experiment and it was shown that Shikonin induced both necroptosis and apoptosis. Additionally, it was observed that Shikonin increased the number of T-regulatory cells in subcutaneous tumors.
Conclusion: Necroptotic cell death is a late finding during tumor development, indicating that this type of cell death primarily occurs towards invasive tumor stages. Necroptosis and apoptosis occur in separate hotspots, presumably because the inflammatory environment in one part of the tissue dictates the type of cell death being activated. Necrostatin-1s accelerates tumor growth, which allows one to hypothesize that necroptosis is protective against tumor progression. Shikonin slows down tumor growth likely via a dual induction of necroptosis and apoptosis. This justifies the use of Shikonin in autochthonous induced bladder cancer models, such as in the BBN-induced bladder cancer model. Were Shikonin to show the same antitumorigenic results in the BBN-induced bladder cancer model and other preclinical models, more clinical trials could be conducted with the purpose of gaining more data on this new compound and its possible clinical applications.
Abstract (croatian) Ciljevi: Iako je postignut veliki napredak u liječenju tumora mokraćnog mjehura, preživljenje kod osoba s mišićno invazivnim tumorom mokraćnog mjehura i dalje je nisko što opravdava potrebu za novim terapijskim pristupima. Nekroptoza je programirani tip stanične smrti, čija uloga nije do kraja razjašnjena u tumoru mokraćnog mjehura. Cilj ovog istraživanja je proučiti prisutnost nekroptoze u
različitim vremenskim točkama tijekom progresije tumora i istražiti utječe li indukcija ili inhibicija nekroptoze na rast tumora.
Metode: Studija koristi dva različita mišja modela tumora mišjeg mjehura. Prvi je autohtoni model tumora mokraćnog mjehura induciran BBN-om. Drugi je model potkožni tumor iniciran pomoću tumorskih stanica MB49. Miševi s potkožnim tumorima tretirani su s Necrostatin-1s i Shikoninom, dva spoja koji bi trebali imati suprotne učinke - inhibicija i indukcija nektoptoze. Kod tumora je analizirana ekspresija gena pomoću metode Q-PCR, te ekspresija proteina pomoću imunohistokemije i imunoblotinga.
Rezultati: Pokazano je da se nekroptoza javlja u kasnim uznapredovalim fazama tumora mokraćnog mjehura izazvanog BBN-om te da se nekroptoza i apoptoza pojavljuju u prostorno odvojenim nakupinama (hotspots). Miševi tretirani s Necrostatin-1s imali su značajno veće volumene tumora u početnim fazama tretmana ali se je taj efekt izgubio do kraja eksperimenta. Na kraju eksperimenta Necrostatin-1s nije pokazao očekivani inhibitorni učinak na nekroptozu. Miševi tretirani sa Shikoninom imali su značajno manji volumen tumora na kraju eksperimenta, a pokazano je da Shikonin inducira nekroptozu i apoptozu. Uz to, uočeno je da Shikonin povećava broj T-regulatornih stanica u potkožnim tumorima.
Zaključak: Nekroptoza se ponajprije pojavljuje u uznapredovalim stadijima invazivnog tumora mokraćnog mjehura. Nekroptoza i apoptoza prisutna je u prostorno odvojenim nakupinama u tumoru, vjerojatno zbog različitog upalnog mikrookoliša u tumoru koji diktira koja vrsta stanične smrti će se aktivirati. Nekrostatin-1 ubrzava rast tumora, što upućuje zaštitnu ulogu nekroptoze kod progresije tumora. Shikonin usporava rast tumora pri čemu inducira nekroptozu i apoptozu. To opravdava upotrebu Shikonina u autohtonom modelu BBN-om induciranog tumora mokraćnog mjehura. Daljnja istraživanja antitumorskog učinka Shikonina na modelu tumora mokraćnog mjehura izazvanog BBN-om kao i na drugim pretkliničkim modelima bila bi dobra osnova za potencijalna buduća klinička ispitivanja i eventualnu kliničku primjenu Shikonina u liječenju tumora mokraćnog mjehura.
Keywords
Urinary Bladder Neoplasm
Necroptosis
Keywords (croatian)
Novotvorine mokraćnog mjehura
Nekroptoza
Language english
URN:NBN urn:nbn:hr:171:488307
Study programme Title: Medical Studies in English Study programme type: university Study level: integrated undergraduate and graduate Academic / professional title: doktor/doktorica medicine (doktor/doktorica medicine)
Type of resource Text
File origin Born digital
Access conditions Open access
Terms of use
Created on 2021-07-06 07:38:45