Unknown,Transcriptomics,Genomics,Proteomics

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Deep sequencing reveals abundant non-canonical onco-retroviral microRNAs in B-cell leukemia/lymphoma

ABSTRACT: Viral tumor models have significantly contributed to our understanding of oncogenic mechanisms. How transforming delta-retroviruses induce malignancy however remains poorly understood, especially as viral mRNA/protein are tightly silenced in tumors. Here, using deep sequencing of broad windows of small RNA sizes in the Bovine Leukemia Virus ovine model of leukemia/lymphoma, we provide evidence of the production of non-canonical Pol III-transcribed viral microRNAs in leukemic B-cells in the complete absence of Pol II 5' LTR-driven transcriptional activity. Processed from a cluster of five independent self-sufficient transcriptional units located in a proviral region dispensable for in vivo infectivity, BLV microRNAs represent ~ 40 % of all microRNAs in both experimental and natural malignancy. They are conserved across tumors and associate with Argonautes, consistent with a critical function in silencing of important cellular and/or viral targets. BLV microRNAs are strongly expressed at pre-leukemic stages and remain at high levels in malignant cells despite the absence of structural and regulatory gene expression, suggesting a key role in tumor onset and progression. Identification of small RNA populations in BLV-induced leukemia

ORGANISM(S): Ovis aries

SUBMITTER: Nicolas Rosewick

PROVIDER: E-GEOD-42316 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Deep sequencing reveals abundant noncanonical retroviral microRNAs in B-cell leukemia/lymphoma.

Rosewick Nicolas N Momont Mélanie M Durkin Keith K Takeda Haruko H Caiment Florian F Cleuter Yvette Y Vernin Céline C Mortreux Franck F Wattel Eric E Burny Arsène A Georges Michel M Van den Broeke Anne A

Proceedings of the National Academy of Sciences of the United States of America 20130123 6

Viral tumor models have significantly contributed to our understanding of oncogenic mechanisms. How transforming delta-retroviruses induce malignancy, however, remains poorly understood, especially as viral mRNA/protein are tightly silenced in tumors. Here, using deep sequencing of broad windows of small RNA sizes in the bovine leukemia virus ovine model of leukemia/lymphoma, we provide in vivo evidence of the production of noncanonical RNA polymerase III (Pol III)-transcribed viral microRNAs in ...[more]

PMID: 23345446

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Project description:Melanoma recurrence frequently occurs after a latency period of several years. In vivo studies demonstrated that tumor cells overcoming latency show a T cell-edited phenotype, suggesting a relevant role for CD8+ T cells in maintaining metastatic latency. Here, in a patient model of multiple recurrent lesions, we illustrate the genetic evolution of poorly immunogenic melanoma phenotypes, evolving in the presence of autologous tumor antigen-specific CD8+ T cells. Melanoma cells from two of three late recurrent metastases, developing within a 6-year latency period, lacked HLA class I expression. HLA class I-negative tumor cells became clinically apparent 1.5 and 6 years into stage IV disease. Genome profiling by SNP arrays revealed total T-cell resistance in both metastases originating from a shared chromosome 15q alteration and independently acquired focal B2M gene deletions. A third HLA class I-positive lesion developed in year 3 of stage IV disease. By HLA haplotype loss lesion-derived melanoma cells acquired resistance towards dominant T-cell clonotypes targeting early stage III tumor cells. Early disease melanoma cells showed a dedifferentiated MITFnegative phenotype, recently described to be associated with immunosuppression, in contrast to the MITFhigh phenotype of T cell-edited tumor cells from late metastases. In summary, our study demonstrates that tumor recurrences after long-term latency develop towards T-cell resistance by independent genetic events, suggesting a mechanism of T cell-driven genetic evolution of melanoma as a means to evade immune recognition and tumor immunotherapy. Genetic alterations lead to loss of tumor antigen presentation. Cell lines were generated from tumor material, differences in T cell recognition were observed and Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from the cell lines. SNP analysis of different melanoma cell lines obtained from one melanoma patient (4 cell lines from different metastasis of one patient with matching germline DNA).

Dataset Information

Deep sequencing reveals abundant non-canonical onco-retroviral microRNAs in B-cell leukemia/lymphoma

Publications

Deep sequencing reveals abundant noncanonical retroviral microRNAs in B-cell leukemia/lymphoma.

Similar Datasets

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