| 1. |
- Fryknäs, Mårten, 1974-
(författare)
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Molecular Screening for Target Discovery in Cancer
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cancer is one of the major causes of death in the western world. Resistance to anti-cancer drugs and diagnostic difficulties are major obstacles to successful treatment. This thesis describes studies based on microarray expression analysis and high-throughput compound screening for identification of resistance mechanisms, drug targets and diagnostic markers. In paper I-IV, we applied global expression analysis and measurements of drug response in a human tumor cell line panel to identify drug targets and resistance mechanisms. In paper I, we identified gene transcript levels that correlate with drug resistance and sensitivity. Both well known and new potential markers and mechanisms were identified. In paper II, we showed that STAT1 activity is associated with cross-resistance to both doxorubicin and radiation in vitro and that fludarabine can counteract STAT1 activity and reduce resistance. In Paper III-IV, cell lines were exposed to a compound library consisting of more than thousand different substances in a high-throughput screening effort. These studies revealed that cell line models of squamous cell carcinoma (Paper III) and drug resistant myeloma (Paper IV) are sensitive to phosphodiesterase inhibitors and glucocorticoids respectively. The target molecules for these drugs were over-expressed at the mRNA level and constitute likely explanations for the observed drug potency. In paper V, we identified mRNA markers for the distinction between two types of thyroid tumors, thyroid follicular adenomas and thyroid follicular carcinomas, by means of microarray expression analysis. Our results indicated that distinction between the two tumor types is possible with a small number of markers.
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| 2. |
- Handin, Niklas
(författare)
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Proteomics informed investigation of human hepatocytes and liver tissue
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A successful drug needs to display beneficial absorption, distribution, metabolism, excretion and toxicity (ADME-Tox) profile. It is therefore important to investigate these properties during the drug discovery process. The liver is of particular interest in ADME-Tox studies, as it is highly metabolically active and oral administrated drugs needs to pass the liver before reaching the systemic circulation. However, a dose of a drug that is efficacious and safe for one individual may be inefficacious or toxic, because of inter-individual variability. Therefore, it is important to investigate the ADME-Tox properties in a sufficiently large population. Investigations on ADME-Tox is usually done in in vitro cell models. Therefore, a variety of models to simulate liver functions have been developed and ranging from subcellular microsomes to complex 3D organoid cultures. This thesis investigates variability of ADME proteins in human liver tissue and in liver cell models.First, mass spectrometry based targeted proteomics was used to quantify ADME relevant proteins from 149 human liver samples. The observed inter-individual protein variability could not solely be explained by genotype. Therefore, a single transporter protein, the bile and drug transporting protein, NTCP, was investigate in detail. Non-genetic factors, e.g. smoking and alcohol consumption, and epigenetic factors such as DNA methylation, were found to contribute to the observed inter-individual variability of NTCP. Next, hepatocytes (PHH) were isolated from 54 human livers tissues and after which the hepatocytes where cryopreserved. The variable attachment efficiency of cryopreserved hepatocytes where investigated and an apoptosis inhibition protocol for restoration of attachment properties was developed. This protocol was also successfully applied to 3D cultured PHH spheroids resulting in increased ability to form 3D spheroids. The effect of culture conditions on the quality of the 3D cultures was also investigated. 3D PHH spheroids were formed and maintained in different, commonly used culture media. The spheroids were characterized by a variety of functional assays including global proteomics. The proteome analysis showed that while no epithelial to mesenchymal transitions was observed, 3D cultures maintained in fasting glucose and insulin levels resembling the in vivo situation showed a more liver-like phenotype with a high expression of ADME proteins and functional cytochrome P450 metabolism. Transporter kinetics were also investigated in the 3D cultured PHH. Finally, we investigated if global proteomics data from 56 human liver tissues could be deconvoluted to give information about the liver composition. The cell type proportions generated by deconvolution where similar to literature values. Liver samples that displayed deviating cell composition were identified. The deviating liver compositions were in agreement with clinical markers of inflammation in the patient´s blood samples and with altered extracellular matrix protein composition, comparable to that found in liver steatosis. In conclusion, this thesis have investigated variability in ADME proteins in human liver and in in vitro cultures of human hepatocytes, characterized cofounding factors for in vitro cultured hepatocytes and further extended drug disposition studies in 3D cultured hepatocytes.
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| 3. |
- Nazir, Madiha
(författare)
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Drug Repositioning for Cancer Treatment : Novel Candidate Identification Strategies
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Regardless of the enormous investments in cancer research and drug development, the proportion of approved drugs in oncology is low compared to other indications, and new avenues are needed. One attractive approach in this regard is drug repositioning where new uses outside the scope of the original medical indications for existing drugs are identified. It offers the advantages of reduced development risks, time and cost over de novo drug discovery pathways.The main focus of this thesis was to explore and employ different strategies to identify repurposable drug candidates for treatment of cancer. Aiming for this, in the first project we followed a bioinformatics approach to evaluate PDE3A as a drug target and biomarker. We showed that subgroups of tumors, within many different cancer types, overexpress PDE3A (mRNA and protein) and that PDE3A can predict sensitivity to the clinically tested phosphodiesterase inhibitors zardaverine and quazinone (Paper I). In the second project, a novel automated image based microscopy assay was developed and used for detection of apoptotic cells. In a screen the method was successfully used to identify apoptosis inducing compounds. Two of these apoptosis inducers were found to have repurposing potential (Paper II). Moreover, high-throughput combination screening was performed using different cell models. In paper III, monolayer cell cultures were used as cell model to search for combination partners for the anti-parasitic compound mebendazole (a repurposing candidate). As a result, the antipsychotic drug thioridazine was found to have synergistic effect when combined with mebendazol. Finally, a novel drug-combination platform for three-dimensional cell culture based screening, in 384 well formats, was developed. This assay was used to search for combination partners to the anti-parasitic compound nitazoxanide (a repurposing candidate), which was previously reported to specifically target quiescent cancer cells. The screen identified the antifungal agent ketoconazole as selectively toxic to hypoxic and nutrient deprived cancer cells when combined with nitazoxanide (Paper IV). Thus, we have developed/explored several methodological approaches and identified drugs that potentially can be repurposed for treatment of cancer.
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| 4. |
- Selvin, Tove
(författare)
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Preclinical tumor-immune modeling : For the identification of immunomodulatory drugs
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- For a long time, the field of cancer research was dominated by a tumor cell-centric view. That, however, changed once it became recognized that medical cancer treatment is largely influenced by the combined effect exerted on both cancer and immune cells. In this work, we aimed to develop and apply preclinical model systems for the identification and evaluation of immunomodulatory anti-cancer agents. In Paper I, we employed single-cell RNA sequencing (scRNA-seq) to investigate immunological effects of trifluridine (FTD), a nucleoside analogue used for the treatment of colorectal cancer (CRC). The study revealed that while FTD induces immunogenic cell death (ICD), it may also attenuate T cell-mediated antitumor responses. In paper II and III, we developed and applied a phenotypic screening platform based on a miniaturized tumor-immune model. In paper II, aiming to identify immunological effects of clinical relevance and provide a reference point for screening novel compound libraries, the model system was used to assess a broad panel of standard anticancer agents. In paper III, the platform was used to screen a drug library containing 1280 small molecule drugs, all approved by the FDA or other agencies. Using this approach, statins were identified as enhancers of immune cell-mediated cancer cell killing. Finally, in paper IV, we developed the immuno-oncology hollow fiber assay (HFA) with the goal of bridging the gap between cell based in vitro assays and more complex mouse models for evaluation of immuno-oncological agents. The HFA is an in vivo assay in which semipermeable fibers are filled with cancer cells and implanted in rodents. We further developed the HFA to incorporate both cancer and immune cells. This novel assay demonstrated the potential to capture immune-mediated cancer cell killing in vivo within a matter of days. Collectively, this work provides a research approach for immuno-oncology drug screening, in vitro validation, and initial in vivo evaluation.
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| 5. |
- Senkowski, Wojciech
(författare)
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High-throughput screening using multicellular tumor spheroids to reveal and exploit tumor-specific vulnerabilities
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High-throughput drug screening (HTS) in live cells is often a vital part of the preclinical anticancer drug discovery process. So far, two-dimensional (2D) monolayer cell cultures have been the most prevalent model in HTS endeavors. However, 2D cell cultures often fail to recapitulate the complex microenvironments of in vivo tumors. Monolayer cultures are highly proliferative and generally do not contain quiescent cells, thought to be one of the main reasons for the anticancer therapy failure in clinic. Thus, there is a need for in vitro cellular models that would increase predictive value of preclinical research results. The utilization of more complex three-dimensional (3D) cell cultures, such as multicellular tumor spheroids (MCTS), which contain both proliferating and quiescent cells, has therefore been proposed. However, difficult handling and high costs still pose significant hurdles for application of MCTS for HTS.In this work, we aimed to develop novel assays to apply MCTS for HTS and drug evaluation. We also set out to identify cellular processes that could be targeted to selectively eradicate quiescent cancer cells. In Paper I, we developed a novel MCTS-based HTS assay and found that nutrient-deprived and hypoxic cancer cells are selectively vulnerable to treatment with inhibitors of mitochondrial oxidative phosphorylation (OXPHOS). We also identified nitazoxanide, an FDA-approved anthelmintic agent, to act as an OXPHOS inhibitor and to potentiate the effects of standard chemotherapy in vivo. Subsequently, in Paper II we applied the high-throughput gene-expression profiling method for MCTS-based drug screening. This led to discovery that quiescent cells up-regulate the mevalonate pathway upon OXPHOS inhibition and that the combination of OXPHOS inhibitors and mevalonate pathway inhibitors (statins) results in synergistic toxicity in this cell population. In Paper III, we developed a novel spheroid-based drug combination-screening platform and identified a set of molecules that synergize with nitazoxanide to eradicate quiescent cancer cells. Finally, in Paper IV, we applied our MCTS-based methods to evaluate the effects of phosphodiesterase (PDE) inhibitors in PDE3A-expressing cell lines.In summary, this work illustrates how MCTS-based HTS yields potential to reveal and exploit previously unrecognized tumor-specific vulnerabilities. It also underscores the importance of cell culture conditions in preclinical drug discovery endeavors.
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| 6. |
- Strese, Sara, 1978-
(författare)
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Anticancer Activity of Melflufen : Preclinical Studies of a Novel Peptidase-Potentiated Alkylator
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Melflufen (melphalan flufenamide, chemical name L-melphalanyl-p-L-fluorophenylalanine ethyl ester hydrochloride, previously called J1) is a derivative of the classical alkylating agent melphalan. Melflufen is potentiated by hydrolytic cleavage by aminopeptidase N (APN), leading to high intracellular concentrations of alkylating moieties and subsequent cell death. Increased APN expression is associated with the malignant phenotype of several human cancers, including acute myeloid leukemia, lymphoma and ovarian cancer, and plays a functional role in tumor angiogenesis. Therefore investigations of melflufen activity in these malignancies as well as detailed studies of inhibition of angiogenesis are interesting. The aim of this project was to investigate the cytotoxic and antiangiogenic effect, in vitro and in vivo, of melflufen, compared to melphalan and other cytotoxic drugs used in the clinic.We showed that melflufen was more effective than its parental drug melphalan in lymphoma, AML and ovarian cancer in cell lines as well as in primary patient samples. An improved in vitro therapeutic index was demonstrated by an increased cytotoxic activity in the patient samples compared to normal peripheral blood mononuclear cells (PBMCs). Furthermore, melflufen in combination with cytarabine was synergistic in an AML cell line in a sequence-dependent manor. Melflufen was shown effective in several animal models using lymphoma, AML and ovarian cell xenografts (single drug or in combination), including an intraperitoneal ovarian xenograft. Finally, we demonstrated that melflufen had antiangiogenic properties in several different models.
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