101. TRBP2, a Major Component of the RNAi Machinery, Is Subjected to Cell Cycle-Dependent Regulation in Human Cancer Cells of Diverse Tissue Origin.
- Author
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Theotoki, Eleni I., Kakoulidis, Panos, Velentzas, Athanassios D., Nikolakopoulos, Konstantinos-Stylianos, Angelis, Nikolaos V., Tsitsilonis, Ourania E., Anastasiadou, Ema, and Stravopodis, Dimitrios J.
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TUMOR diagnosis , *PROTEIN metabolism , *RNA-binding proteins , *FLOW cytometry , *RESEARCH funding , *ALZHEIMER'S disease , *CARDIOMYOPATHIES , *MICRORNA , *CELL physiology , *CELL cycle , *FLUORESCENT antibody technique , *GENE expression , *CELL division , *CELL lines , *BIOINFORMATICS , *METASTASIS , *GENETIC techniques , *TUMORS - Abstract
Simple Summary: Engagement of an advanced immunofluorescence technology demonstrated, for the first time, the cell cycle-dependent control of TRBP2 protein, a major component of the RNAi machinery. TRBP2 expression is lost during mitosis and restored in the cell nucleus upon interphase entry. None of the post-translational modifications, such as ubiquitination or phosphorylation, herein examined proved able to play an essential role in TRBP2 loss from the nucleus of mitotic cells. Different types of cancer cells, with diverse tissue origin, malignancy grade, metastatic potential, and mutational load, are shown to lack TRBP2 nuclear compartmentalization during mitosis, thereby opening new diagnostic and therapeutic windows for human malignancies in the clinic. Background: Transactivation Response Element RNA-binding Protein (TRBP2) is a double-stranded RNA-binding protein widely known for its critical contribution to RNA interference (RNAi), a conserved mechanism of gene-expression regulation mediated through small non-coding RNA moieties (ncRNAs). Nevertheless, TRBP2 has also proved to be involved in other molecular pathways and biological processes, such as cell growth, organism development, spermatogenesis, and stress response. Mutations or aberrant expression of TRBP2 have been previously associated with diverse human pathologies, including Alzheimer's disease, cardiomyopathy, and cancer, with TRBP2 playing an essential role(s) in proliferation, invasion, and metastasis of tumor cells. Methods: Hence, the present study aims to investigate, via employment of advanced flow cytometry, immunofluorescence, cell transgenesis and bioinformatics technologies, new, still elusive, functions and properties of TRBP2, particularly regarding its cell cycle-specific control during cancer cell division. Results: We have identified a novel, mitosis-dependent regulation of TRBP2 protein expression, as clearly evidenced by the lack of its immunofluorescence-facilitated detection during mitotic phases, in several human cancer cell lines of different tissue origin. Notably, the obtained TRBP2-downregulation patterns seem to derive from molecular mechanisms that act independently of oncogenic activities (e.g., malignancy grade), metastatic capacities (e.g., low versus high), and mutational signatures (e.g., p53−/− or p53ΔΥ126) of cancer cells. Conclusions: Taken together, we herein propose that TRBP2 serves as a novel cell cycle-dependent regulator, likely exerting mitosis-suppression functions, and, thus, its mitosis-specific downregulation can hold strong promise to be exploited for the efficient and successful prognosis, diagnosis, and (radio-/chemo-)therapy of diverse human malignancies, in the clinic. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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