Epstein-Barr virus (EBV) infection of primary human B cells drives their indefinite proliferation into lymphoblastoid cell lines (LCLs). B cell immortalization depends on expression of viral latency genes, as well as the regulation of host genes. Given the important role of microRNAs (miRNAs) in regulating fundamental cellular processes, in this study, we assayed changes in host miRNA expression during primary B cell infection by EBV. We observed and validated dynamic changes in several miRNAs from early proliferation through immortalization; oncogenic miRNAs were induced, and tumor suppressor miRNAs were largely repressed. However, one miRNA described as a p53-targeted tumor suppressor, miR-34a, was strongly induced by EBV infection and expressed in many EBV and Kaposi's sarcoma-associated herpesvirus (KSHV)-infected lymphoma cell lines. EBV latent membrane protein 1 (LMP1) was sufficient to induce miR-34a requiring downstream NF-κB activation but independent of functional p53. Furthermore, overexpression of miR-34a was not toxic in several B lymphoma cell lines, and inhibition of miR-34a impaired the growth of EBV-transformed cells. This study identifies a progrowth role for a tumor-suppressive miRNA in oncogenic-virus-mediated transformation, highlighting the importance of studying miRNA function in different cellular contexts.
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http://dx.doi.org/10.1128/JVI.07056-11 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing 210096, China.
Heterogeneous roles of complement C3 have been implicated in tumor metastasis and are highly context dependent. However, the underlying mechanisms linking C3 to tumor metastasis remain elusive in renal cell carcinoma (RCC). Here, we demonstrate that C3 of RCC cell-derived extracellular vesicles (EVs) contributes to metastasis via polarizing tumor-associated macrophages (TAMs) into the immunosuppressive phenotype and recruiting polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs).
View Article and Find Full Text PDFMol Biol Rep
January 2025
Department of Biochemistry, All India Institute of Medical Sciences, Jodhpur, Rajasthan, 342005, India.
Background: Differential DNA methylation in the promoter region of tumour suppressor genes leads to gene function silencing.
Materials And Methods: In this study, we aimed to evaluate the salivary promoter methylation of EDNRB, MGMT and TIMP3 genes in H&NC patients (n = 100), premalignant lesions patients (n = 25) and healthy controls (n = 50). Blood and saliva samples were collected from all three groups and 20 concomitant tumour tissues were collected from the H&NC patients.
Cell Mol Life Sci
January 2025
Institute of Endotypes in Oncology, Metabolism, and Immunology, National Research Council, Via Pietro Castellino 111, Naples, Italy.
Breast cancer represents the primary cause of death of women under 65 in developed countries, due to the acquisition of multiple drug resistance mechanisms. The PI3K/AKT pathway is one of the major regulating mechanisms altered during the development of endocrine resistance and inhibition of steps in this signalling pathway are adopted as a key strategy to overcome this issue. ADP-ribosylation is a post-translational modification catalysed by PARP enzymes that regulates essential cellular processes, often altered in diseases.
View Article and Find Full Text PDFProteomes
January 2025
Instituto de Matemática e Estatística, Departamento de Ciência da Computação, Universidade de São Paulo, Rua do Matão 1010, São Paulo 05508-090, SP, Brazil.
The tumor suppressor p53, in its wild-type form, plays a central role in cellular homeostasis by regulating senescence, apoptosis, and autophagy within the DNA damage response (DDR). Recent findings suggest that wild-type p53 also governs ferroptosis, an iron-dependent cell death process driven by lipid peroxidation. Post-translational modifications of p53 generate proteoforms that significantly enhance its functional diversity in regulating these mechanisms.
View Article and Find Full Text PDFCurr Drug Targets
January 2025
Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang, 443002, China.
Metallothionein 1J pseudogene (MT1JP) is a long non-coding RNA (lncRNA) that functions as a tumor suppressor in various malignancies. Reduced MT1JP expression is associated with increased tumor proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and treatment resistance in nine cancers, such as gastric cancer, intrahepatic cholangiocarcinoma, hepatocellular carcinoma, and breast cancer. Mechanistically, MT1JP acts as a competitive endogenous RNA (ceRNA) to regulate oncogenic microRNAs (miRNAs), including miR-92a-3p, miR-214-3p, and miR-24-3p.
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