Okada Ryu, Takenobu Hisanori, Satoh Shunpei, Sugino Ryuichi P, Onuki Ritsuko, Haruta Masayuki, Mukae Kyosuke, Nakazawa Atsuko, Akter Jesmin, Ohira Miki, Kamijo Takehiko
Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama, Japan.
Laboratory of Tumor Molecular Biology, Department of Graduate School of Science and Engineering, Saitama University, Saitama, Japan.
Genes Cells. 2024 Oct;29(10):838-853. doi: 10.1111/gtc.13148. Epub 2024 Aug 27.
Epigenetic alterations critically affect tumor development. Polycomb-group complexes constitute an evolutionarily conserved epigenetic machinery that regulates stem cell fate and development. They are implicated in tumorigenesis, primarily via histone modification. Polycomb repressive complex 1 (PRC1) complexes 1-6 (PRC1.1-6) mediate the ubiquitination of histone H2A on lysine 119 (H2AK119ub). Here, we studied the functional roles of a PRC1.6 molecule, L3MBTL2, in neuroblastoma (NB) cells. L3MBTL2-knockout and knockdown revealed that L3MBTL2 depletion suppressed NB cell proliferation via cell-cycle arrest and gamma-H2A.X upregulation. L3MBTL2-knockout profoundly suppressed xenograft tumor formation. Transcriptome analysis revealed suppressed cell-cycle-related and activated differentiation-related pathways. Break repair meiotic recombinase recruitment factor 1 (BRME1) and nuclear receptor interacting protein 3 (NRIP3) were notably de-repressed by L3MBTL2-knockout. The deletion of L3MBTL2 reduced enrichment of H2AK119ub and PCGF6 at transcriptional start site proximal regions of the targets. Add-back studies unveiled the importance of L3MBTL2-BRME1 and -NRIP3 axes for NB cell proliferation. We further manifested the association of MYCN with de-repression of NRIP3 in an L3MBTL2-deficient context. Therefore, this study first revealed the significance of L3MBTL2-mediated gene silencing in MYCN-amplified NB cells.
表观遗传改变对肿瘤发展具有关键影响。多梳蛋白家族复合体构成了一种进化上保守的表观遗传机制，可调节干细胞命运和发育。它们主要通过组蛋白修饰参与肿瘤发生。多梳抑制复合体1（PRC1）复合体1 - 6（PRC1.1 - 6）介导组蛋白H2A在赖氨酸119位点（H2AK119ub）的泛素化。在此，我们研究了PRC1.6分子L3MBTL2在神经母细胞瘤（NB）细胞中的功能作用。L3MBTL2基因敲除和敲低表明，L3MBTL2缺失通过细胞周期阻滞和γ-H2A.X上调抑制NB细胞增殖。L3MBTL2基因敲除显著抑制异种移植瘤形成。转录组分析显示细胞周期相关通路受到抑制，而分化相关通路被激活。断裂修复减数分裂重组酶募集因子1（BRME1）和核受体相互作用蛋白3（NRIP3）在L3MBTL2基因敲除后显著去抑制。L3MBTL2的缺失减少了靶点转录起始位点近端区域H2AK119ub和PCGF6的富集。回补研究揭示了L3MBTL2 - BRME1和 - NRIP3轴对NB细胞增殖的重要性。我们进一步证明了在L3MBTL2缺陷背景下MYCN与NRIP3去抑制的关联。因此，本研究首次揭示了L3MBTL2介导的基因沉默在MYCN扩增的NB细胞中的重要性。
