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| Author(s): |
Ana Júlia Rossoni Carvalho
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2023-05-24 |
| Examining board members: |
Andréia Machado Leopoldino;
Elza Tiemi Sakamoto Hojo;
Flávia Cristina Rodrigues Lisoni
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| Advisor: | Andréia Machado Leopoldino |
| Abstract | |
Higher levels of the heterogeneous ribonucleoprotein K (hnRNP K) has been described in different types of cancer and is associated with worse a prognosis, including in oral cancers. This protein binds itself to RNA and DNA, participating in different protein-protein regulatory activities, and can be found in the nucleus, cytoplasm and mitochondria. HnRNP K is the target for different post-translational changes, such as methylation and phosphorylation, which regulate its interactions with other proteins and its subcellular localization, allowing hnRNP K to participate in different genomic regulation mechanisms. The aim of this study was to study hnRNP K\'s potential role in the mismatch repair system by its interaction with YB1, an important protein for the mitochondrial mismatch repair. We used normal oral keratinocytes cell lines (NOK-SI) with overexpression or lower levels of hnRNP K with or without treatment of methotrexate (which causes oxidating DNA damages) and U0126 (a phosphorylation inhibitor capable of inhibiting hnRNP K\'s phosphorylation and its subsequent translocation to the cytoplasm). Protein fraction analysis of mitochondrial, nucleus and whole cell lysates through western blot and immunofluorescence have shown that higher hnRNP K levels in the nucleus increases the levels of p53, as well as YB1 in the mitochondria. Electrophoretic mobility shift assays of oligomer sequences containing a mismatch or insertion with mitochondrial and nuclear protein fractions show hnRNP K overexpressing cells decreasing the mismatch repair in the mitochondria. On the other hand, comet assays show that hnRNP K overexpression in cells exposed to oxidative damages caused by methotrexate has a protective effect in the cells. HnRNP K, therefore, has a negative effect in the mismatch repair system of mitochondrial DNA, but favors cell death resistance, indirectly regulating the mismatch repair system, which can lead to hnRNP K protecting the cell by other means, such as metabolic reprogramming and lower levels of oxidating stress. (AU) | |
| FAPESP's process: | 19/16914-8 - Heterogeneous ribonucleoprotein K role in DNA repair in oral epidermoid cells |
| Grantee: | Ana Júlia Rossoni Carvalho |
| Support Opportunities: | Scholarships in Brazil - Master |