Browsing by Subject "Sorafenib"
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Item Embargo Drug repurposing and investigation of novel combinations for glioblastoma therapeutics using in vitro and zebrafish in vivo models(Bilkent University, 2024-01) Tok, GüneşGlioblastoma is the most common and aggressive brain cancer type with the survival rate less than 2 years after diagnosis. Yet, potent drug treatments used in patients are limited and the field is in need of development of new potential drugs. In this study, repurposing of approved drugs alone or in combination and novel drugs are investigated in terms of inhibition of cell viability, glial fluorescent signals and their effects on behavior in zebrafish larval models. The main aim of this study was to test whether phenothiazines, trifluoperazine and a novel molecule 10, could be repurposed for glioblastoma treatment with lower dosages and more potency when combined with Sorafenib, an approved drug, in glioblastoma cell lines and zebrafish larvae. Those drug combinations were not found as toxic in the dosages studied while acted on glia cells in zebrafish transgenic larval models. Last but not least, behavior and stress response of the wild type and heterozygous mutant ache larvae in comparison with homozygous siblings were tested upon drug administration to assess genotype by drug interactions. Combination treatments exhibited higher efficacies suggesting phenothiazines with sorafenib could have potential in glioblastoma treatment. Genotype specific effects of individual and combination treatments on larval light-dark behavior, stress response and recovery exhibited potential for passage of blood brain barrier by the tested drugs. The established protocols for genotype and drug interactions could be applied to other kinases in combination with phenothiazines.Item Open Access Effects of PI3K/AKT/MTOR and VEGFR pathway inhibitors on liver cancer stem cells and bioactivities of novel pyrazolic chalcone derivatives on liver cancer(Bilkent University, 2017-12) Kahraman, Deniz CansenHepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality, such that it the second most frequent cause of cancer death worldwide. Due to its heterogeneous composition and aggressive behavior, it is resistant to conventional therapies and also Sorafenib and Regorafenib which are FDA-approved multikinase inhibitors targeting pathways involved in angiogenesis and proliferation. The mechanisms behind the acquired resistance to Sorafenib were described as activation of compensatory pathways such as PI3K/Akt/mTOR, JAK-STAT, epithelial to mesenchymal transition (EMT), microenvironment and presence of cancer stem cells. Liver cancer stem cells originate from damaged and transformed hepatic progenitor cells (HPCs) which are found responsible for chemo-resistance, tumor relapse, and metastasis. For this reason, the effects of PI3K/Akt/mTOR inhibitors, Sorafenib and DNA intercalators on the enrichment of LCSCs were investigated. CD133+/EpCAM+ population from HCC cells were analyzed by flow cytometry after treatment with inhibitors, and effective inhibitors against LCSCs were further tested for their potential combinatorial effects together with Sorafenib. It was shown that upon treatment with Sorafenib or DNA intercalators the LCSCs were enriched, whereas Rapamycin (mTOR inhibitor), LY294002 (PI3K inhibitor) were able to inhibit the enrichment of LCSCs and reduced the CD133+/EpCAM+ population ratio. Combination studies revealed that when cells are treated initially with Rapamycin and then with Sorafenib, both the LCSC ratio and the sphere formation capacity of cells were reduced compared to cells treated with Sorafenib alone. To understand the alterations in gene expression induced by the inhibitors, a large panel of genes involved in regulation of cancer pathways were analyzed using Nanostring nCounter Technology. Systematic pathway analysis using Cytoscape Score Flow algorithm application allowed us to identify differential response genes involved in stemness. It was shown that genes involved in regulation of stem cells (Wnt and Notch pathway) were downregulated upon treatment with Rapamycin and DAPT (Notch pathway inhibitor), yet Sorafenib treatment resulted in differential regulation of these pathways, where JAG1 gene was found to be up-regulated. Interestingly, IL-8 expression was upregulated dramatically upon treatment with Sorafenib, but downregulated upon DAPT or Rapamycin treatment. Inhibition of IL-8 signaling resulted in reduction in both LCSC ratio and sphere formation capacity of HCC cells, which could be indicating the role of IL-8 signaling in the conservation of stemness features of LCSCs. For this reason, blockade of IL-8 signaling was suggested to be a promising therapeutic approach for HCC. Another topic in this thesis focuses on the potential of VEGFR2 TKIs and quinoids to inhibit both liver cancer cells and liver cancer stem cells. VEGFR TKIs such as Sorafenib, are widely studied for the treatment of many cancers, yet as mentioned above, there are many clinical studies providing the evidence that anti-VEGF or anti-VEGFR therapies lead to stable disease, which is then followed by disease progression in different cancer types. In recent years it has also been shown that antiangiogenic agents are increasing cancer stem cell population via generation of tumor hypoxia. Quinoids, on the other hand, are compounds that are selectively active in hypoxic conditions. Thus, the main aim of this study was to evaluate the bioactivities of compounds from each group on liver cancer cells and also to analyze their effects on the enrichment of LCSCs. Our results have shown that VEGFR2 TKIs were cytotoxic at lower concentrations compared to quinoids. However, it was shown that VEGFR2 TKIs are more likely to enrich LCSC population whereas some of the quinoids were able to reduce this ratio. With this information, a new concept called “aggressiveness factor”, which defines the potential of a compound to cause more aggressive cancer, was introduced. In the last part of this thesis, bioactivities of pyrazolic chalcone derivatives on HCC cell lines and their mechanism of action were investigated. Chalcones and pyrazolic structures are well known for their anti-cancer activities. Newly synthesized pyrazolic chalcone derivatives were tested against different cancer cells, and selection based on the IC50 values of compounds was made to analyze their effect on a panel of HCC cells. Results have shown that, compounds 39, 42, 49 and 52 were the most effective derivatives which had anti-proliferative activities in less than 5 μM concentrations. Further investigation of cell cycle progression and cell death mechanisms have revealed that compounds 42 and 52 caused cell cycle arrest at the G2/M phase and induced apoptotic cell death. Also, levels of cell cycle proteins, p21, CDK1, and phospho-CyclinB1 were shown to decrease upon treatment with these compounds.Item Open Access Mineralocorticoid and glucocorticoid receptors as novel targets in breast and liver cancer therapies(Bilkent University, 2020-12) Güneş, DamlaCell signaling is a complex phenomenon and is maintained through intertwined signal transmissions within and in-between the cells. Anti-cancer therapies are often challenged by this fact due to crosstalk-associated activation of alternative survival routes. Hence, development of new treatment strategies and identification of novel prognostic markers depends on in-depth knowledge on cell signaling routes altered in cancer and possible crosstalk paths. Herein, mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) signaling, two closely related members of steroid receptor hormone family, and their possible crosstalk were studied across breast and liver cancer cell lines. In breast cancer cell lines, estrogen responsive and MR expressing T47D was used in order to study possible crosstalk among Estrogen receptor (ER) and MR. MR-GR ligand aldosterone (ALDO) and ER ligand estrogen (E2) administered to breast cancer cells alone and in combination and, MR, ER and GR and their downstream signaling members were studied employing qRT-PCR and Western blot assays. Furthermore, ALDO, E2, ALDO-E2 hormone administrations were also used for cell viability assessments. Our results implied possible interactions of ALDO-E2 signaling at the level of cell viability, and at mRNA levels of progesterone receptor. In liver cancer cell lines, MR and GR was investigated as targets of a novel treatment. Liver cancer subtype hepatocellular carcinoma (HCC) has high mortality rate with limited treatment options. Multi-kinase inhibitor Sorafenib (SFB) with mild effectivity is most known systemic therapy against HCC. To potentiate the effectiveness of SFB and overcome to the crosstalk associated limitations, combinatorial drug treatment approach targeting multiple signaling modalities has been adopted in literature. Previously in our lab, SFB was combined with repurposed anti-psychotic drug TFP as a novel combinatorial treatment against hepatocellular carcinoma (HCC) and liver cancer cell lines. Cellular viability was synergistically reduced by SFB-TFP in HCC cell line Hep3B, while antagonistic effects on viability in SkHep1 was apparent. Herein, two liver cancer cell lines Hep3B and SkHep1, were used in comparison to unravel mechanism of action of SFB-TFP combination at the protein level. Apoptosis, cell cycle, PI3K/AKT/mTOR and MAPK pathways were investigated in addition to MR and GR. Our results revealed several markers indicating success of drug combinations and targeted pathways at protein level which needs to be pursued further.Item Open Access Quinoides and VEGFR2 TKIs influence the fate of hepatocellular carcinoma and its cancer stem cells(Royal Society of Chemistry, 2017) Kahraman, D. C.; Hanquet, G.; Jeanmart, L.; Lanners, S.; Šramel, P.; Boháč, A.; Cetin-Atalay, R.Bioactivities of quinoides 1–5 and VEGFR2 TKIs 6–10 in hepatocellular cancer (HCC) and cancer stem cells (HCSCs) were studied. The compounds exhibited IC50 values in μM concentrations in HCC cells. Quinoide 3 was able to eradicate cancer stem cells, similar to the action of the stem cell inhibitor DAPT. However, the more cytotoxic VEFGR TKIs (IC50: 0.4–3.0 μM) including sorafenib, which is the only FDA approved drug for the treatment of HCC, enriched the hepatocellular cancer stem cell population by 2–3 fold after treatment. An aggressiveness factor (AF) was proposed to quantify the characteristics of drug candidates for their ability to eradicate the CSC subpopulation. Considering the tumour heterogeneity and marker positive cancer stem cell like subpopulation enrichment upon treatments in patients, this study emphasises the importance of the chemotherapeutic agent choice acting differentially on all the subpopulations including marker-positive CSCs.Item Open Access Zebrafish as an in vivo model of drug screens for liver cancer: the role of phenothiazines(Bilkent University, 2021-08) Korkmaz, BüşraHepatocellular 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.