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Germini, D.

Publications and source records attributed to Germini, D..

2 recordsLinked to original sources

Translocation-driven chr19-der(14) interaction is associated with disease-specific transcriptional programs in mantle cell lymphoma

Mantle cell lymphoma (MCL) is defined by the t(11;14)(q13;q32) translocation, which drives constitutive CCND1 expression, yet the broader regulatory consequences of this rearrangement remain incompletely understood. Here, we combined transcriptomic, epigenomic, Hi-C, and 3D-FISH analyses in primary MCL samples and cell lines to investigate the genome-wide impact of t(11;14) on chromatin organization and gene regulation beyond the rearranged chromosomes. We show that MCL cells exhibit widespread enhancer activation, accompanied by expansion of super-enhancer regions. The translocated CCND1 locus repositions toward the nuclear interior and acquires enhancer-like features. Genome-wide analysis highlighted chromosome 19 as a hotspot of transcriptional upregulation. Notably, Hi-C and 3D-FISH revealed recurrent interchromosomal contacts between chromosome 19 and the CCND1 locus, preferentially involving the derivative chromosome. These contacts colocalize with active RNA polymerase II and are associated with increased expression of nearby chr19 genes, suggesting an association between spatial proximity and transcriptional activation in trans. Minnelide treatment reduced chromatin accessibility at the CCND1 locus, decreased the frequency of chr19-der14 interactions, and partially reversed the MCL transcriptional program, while exerting strong anti-tumor effects in vitro and in vivo. Together, these findings identify a recurrent interchromosomal interaction associated with coordinated gene activation in MCL and suggest that spatial genome reorganization contributes to disease-specific transcriptional programs.

cancer biology↗

Large-scale nuclear remodeling and transcriptional deregulation occur on both derivative chromosomes after Mantle cell lymphoma chromosomal translocation

Recurrent chromosomal translocations are found in many blood and solid cancers. Balanced translocations, frequent in lymphoid malignancies, lead to the formation of two aberrant derivative (der) chromosomes. This event often leads to overexpression of an oncogene. In many cases, the expression of an oncogene is not enough to produce a malignant phenotype; however, most part of the studies focus on the events involving the chromosome where the oncogene is located, but rarely the other der chromosome where other oncogenic alterations may potentially arise. Mantle cell lymphoma (MCL), an aggressive B-cell non-Hodgkin lymphoma, is a perfect example of this. In 85% of the cases, it is characterized by the translocation t(11;14), which leads to the overexpression of cyclin D1 (CCND1) gene which results juxtaposed to the immunoglobulin heavy chain (IGH) gene on the der14 chromosome. This feature alone is not sufficient to induce oncogenesis. Here we focused on the der11 chromosome. We demonstrated that expression of 88 genes located in a 15mb region close to the translocation breakpoint on the der11 was deregulated both in the GRANTA-519 MCL cell line and in B-cells from MCL patients. We found that a large segment of der11containing deregulated genes was relocated from its normal position in the nuclear periphery towards the center of the nucleus in close proximity to the nucleolus where the abundant nucleolar protein nucleolin binds a subset of genes located close to the breakpoint and activates their expression. This finding allowed to identify new potential oncogenes involved in MCL and the mechanisms of their upregulation.

cancer biology↗