LEE- Moleküler Biyoloji-Genetik ve Biyoteknoloji Lisansüstü Programı

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http://hdl.handle.net/11527/19400

Gözat

Yazar "Alkurt, Gizem" ile LEE- Moleküler Biyoloji-Genetik ve Biyoteknoloji Lisansüstü Programı'a göz atma
  • Öge
    Variant detection in inflammatory diseases
    (Graduate School, 2024-04-30) Alkurt, Gizem ; Doğanay Dinler, Gizem ; 521162104 ; Molecular Biology-Genetics and Biotechnology
    Cancer remains a public health concern, with a significant number of reported cases worldwide in 2020. 9.3 million cases were diagnosed in men and around 8.8 million cases were diagnosed in women according to 2022 data. From a healthcare perspective, cancer is an influenced by factors such as genetics, environment and inflammation. Cancer is widely recognised as an inflammatory disease, as it is closely linked to an interaction of processes within the body. Inflammation plays a role in the initiation, progression and promotion of cancer. It involves the activation of cells, the release of cytokines and the creation of an inflammatory environment. All of these contribute significantly to stages of cancer development. Therefore it can be deduced that cancer is not caused by mutations, but is also strongly influenced by inflammations. Beyond the events, genetic predisposition adds another layer of complexity that affects not only how the disease manifests, but also how it is treated. The development of cancer is the result of an interplay between hereditary mutations. Tumors associated with cancer syndromes provide insights into genetic conditions. One such syndrome is Lynch syndrome, an inherited disorder that increases the risk of colorectal and endometrial cancers, among others. Mutations in genes such as BRCA1 and BRCA2 are associated with breast and ovarian cancer syndromes, also significantly increase the likelihood of developing these cancers. Our research has explored the link between genetics and cancer by focusing on genes beyond BRCA1 and BRCA2. We examined genes such as ATM, PTEN and CHEK2 that play a role in cancers. For example, ATM mutations increase the risk of breast cancer. PTEN mutations are associated with Cowden syndrome, while CHEK2 mutations increase the risk for both breast and colorectal cancer. We have also investigated Lynch syndrome associated mutations in genes involved in mismatch repair (MLH1, MSH2, MSH6 and PMS2). These mutations are known to make people more susceptible to cancer. Recent studies have highlighted the importance of inherited mutations in determining cancer susceptibility. Therefore, in the first part of this thesis, our aim was to analyze variations in 25 genes associated with cancer susceptibility in a population through a large collaborative effort. The study included 732 breast cancer patients, 189 colorectal cancer patients and 490 elderly cancer-free controls who were free of cancer. The analysis revealed 119 likely pathogenic variations in a total of 149 individuals. Interestingly, around 22.7% of these variations were newly discovered, indicating genetic risks. In addition, 16.0% of the variations were found recurrently among individuals suggesting shared genetic predispositions. In high-risk breast cancer patients, harmful variations in BRCA1 and BRCA2 genes accounted for 61.3% of all identified mutations. Other high-risk breast cancer genes like PALB2, TP53, STK11 and CDH1 also contributed to the mutation spectrum. We also found mutations in genes with penetrance such as CHEK2 and ATM. In cancer cases, Lynch syndrome-related genes accounted for 62.5% of all disease-causing mutations observed. In addition, MUTYH pathogenic variants were present in about 4.4%of high-risk colorectal cancer patients. Interestingly, 2.9% of the control group had a genetic predisposition to cancer based on their family background, but none of them actually had any mutations. It's worth noting that individuals with these mutations also had no family history of cancer. This is possible because of the interaction of proteins that ensure cell survival with these genes and provides preliminary data for a viable project in the future. In the second part of this thesis, we analysed the expression levels of microRNAs in wild type and BAG-1 knockout breast cancer cells. The BAG-1 protein is known for its ability to prevent cell death. It interacts with various other molecules in the cell. These interactions play a role in determining whether cancer cells survive or die. Studies have shown that changes in the levels of BAG-1 protein are associated with types of cancer. In addition, BAG-1 has shown promise as a marker for breast cancer, which is the most common type of cancer in women. Higher levels of BAG-1 are generally associated with increased growth, development and aggressiveness of breast cancer. The presence of miRNAs plays a crucial role in regulating gene expression. To identify these miRNAs, we performed high-throughput sequencing and also determined the target genes and molecular signaling pathways associated with these expressed miRNAs. Of the 25 miRNAs sequenced, we found that 11 were significantly upregulated and14 were downregulated. We experimentally validated 14 out of the 25 miRNAs, among which hsa-miR-429 stood out as a miRNA in BAG-1 KO MCF-7 cells due to its downregulation observed through bioinformatics analysis and other assays. Shifting focus to the global health crisis, the final phase of the thesis examined antibody levels in healthcare workers in the context of the COVID-19 pandemic. The COVID-19 pandemic has highlighted the relationship between infections and the body's immune response particularly inflammation. When someone contracts COVID-19 from the SARS-CoV-2 virus, they may experience levels of inflammation. This natural defense mechanism is the bodys' way of fighting off the virus. Understanding and effectively managing this response is critical to treating COVID-19. Researchers and health professionals are focusing on strategies to regulate how the immune system responds to the virus. The aim is to prevent inflammation that could lead to illness. During the pandemic, we conducted a study of antibody levels in healthcare workers related to COVID-19. As infections continue to increase, it is important to research aspects of the disease. One aspect is to access the extent to which healthcare workers have been exposed to SARS-CoV-2 by testing for immunoglobulin G (IgG) antibodies. This study took place in three hospitals to determine whether healthcare workers (HCWs) had contracted SARS-CoV-2. The main objective was to determine the percentage of HCWs who tested positive for antibodies indicating their exposure to the virus. To measure this we used an microparticle immunoassay that detects antibodies. By analysing the prevalence of IgG antibodies, this research provides insights into HCWs' exposure and immune response to SARS-CoV-2. This information is critical for making decisions on vaccination programs, the need for personal protective equipment (PPE) and implementation of infection control measures in healthcare settings such as hospitals.