• About
  • Policies
  • What is open access
  • Library
  • Contact
Advanced search
      View Item 
      •   BUIR Home
      • University Library
      • Bilkent Theses
      • Theses - Department of Molecular Biology and Genetics
      • Dept. of Molecular Biology and Genetics - Master's degree
      • View Item
      •   BUIR Home
      • University Library
      • Bilkent Theses
      • Theses - Department of Molecular Biology and Genetics
      • Dept. of Molecular Biology and Genetics - Master's degree
      • View Item
      JavaScript is disabled for your browser. Some features of this site may not work without it.

      Zebrafish as an in vivo model of drug screens for liver cancer: the role of phenothiazines

      Thumbnail
      Embargo Lift Date: 2022-03-23
      View / Download
      3.3 Mb
      Author(s)
      Korkmaz, Büşra
      Advisor
      Karakayalı, Özlen Konu
      Date
      2021-08
      Publisher
      Bilkent University
      Language
      English
      Type
      Thesis
      Item Usage Stats
      180
      views
      58
      downloads
      Abstract
      Hepatocellular carcinoma (HCC) is one of the most dangerous cancer types and sorafenib (SFB) is a commonly used drug against HCC, being the only FDA-approved medication until 2018. However, its limited efficacy and severe side effects emphasize the importance of developing alternative approaches. Regulation of cholesterol has been implicated in the progression of various cancers including HCC. Phenothiazines, which are in use as antipsychotic drugs and with effects on cholesterol biosynthesis, have drawn recent attention as anti-cancer drugs against different cancers. The elucidation of how phenothiazines exert their effects at cellular level might pave the way for proposing better strategies for HCC treatment. Zebrafish serves as a good cancer model for in vivo validations, since it enables efficient tumor formation and tracking. Its conserved genes and similar organ system to human make it even better of a model to reveal both molecular and morphological alterations caused by drugs. Based on previous cell viability studies from our lab, the combination of trifluoperazine (TFP) with SFB was found to exhibit synergism in Hep3B cells, while it was antagonistic in SkHep1 cells. Moreover, RNA-seq analysis on Hep3B cells has demonstrated that steroid biosynthesis and cholesterol metabolism was among the modulated pathways. Therefore, in the present thesis, the regulation of cholesterol levels in response to phenothiazine derivatives was investigated in HCC cell lines SkHep1 and Hep3B. The combinatorial approach was examined on Huh7 cells in terms of the expression of cholesterol biosynthesis genes based on RT-qPCR. After showing the ability of phenothiazine derivatives and TFP-SFB combinations to modulate cellular cholesterol, zebrafish drug screens were performed to determine applicable derivative and combination doses. Assessment of safe doses for TFP, SFB and their combination directed us for xenograft studies, which resulted in enhanced Hep3B cell survival by the combination of low dose (6 μM) TFP and 1 μM of SFB. This finding was further validated based on Alu-based DNA quantifiation, a powerful method we have established. With the help of RNA-seq analysis results, orthologous zebrafish genes, involved in cholesterol biosynthesis were identified and used in cross-species testing. The impact of TFP on liver vasculature was evaluated using transgenic (Fli1a:EGFP) zebrafish and found insignificant. Overall, the findings presented in this thesis highlight that TFP alone or in combination was able to change cellular cholesterol levels and tumor growth.
      Keywords
      Hepatocellular carcinoma
      Phenothiazines
      Sorafenib
      Drug repurposing
      Cholesterol
      Zebrafish
      In vivo drug screening
      Xenograft
      Permalink
      http://hdl.handle.net/11693/76545
      Collections
      • Dept. of Molecular Biology and Genetics - Master's degree 165
      Show full item record

      Browse

      All of BUIRCommunities & CollectionsTitlesAuthorsAdvisorsBy Issue DateKeywordsTypeDepartmentsCoursesThis CollectionTitlesAuthorsAdvisorsBy Issue DateKeywordsTypeDepartmentsCourses

      My Account

      Login

      Statistics

      View Usage StatisticsView Google Analytics Statistics

      Bilkent University

      If you have trouble accessing this page and need to request an alternate format, contact the site administrator. Phone: (312) 290 2976
      © Bilkent University - Library IT

      Contact Us | Send Feedback | Off-Campus Access | Admin | Privacy