PO.TB05.03 · 肿瘤生物学
MYC诱导的免疫肽组特征分析
Characterizing the MYC-induced immunopeptidome
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
髓母细胞瘤是最常见的恶性脑肿瘤，通常见于0-9岁儿童，包含四个亚组，每个亚组具有独特的分子特征。分别发生于Group 3和Sonic Hedgehog亚组的携带MYC或MYCN扩增的儿童，面临较低的生存率和较高的转移率。MYC和MYCN均为DNA结合转录因子，通过促进细胞快速分裂来驱动肿瘤发生。本研究探讨MYC(N)上调如何刺激由非经典肽产生免疫原性新抗原，这些新抗原可能作为免疫治疗的新靶点。既往研究表明，转录后调控是MYC生物学的关键组成部分，Group 3肿瘤表现出显著的蛋白质-RNA不同步。有趣的是，MYC优先驱动上游开放阅读框（uORF）的翻译，这些非经典肽大多不稳定，但在MHC-I抗原系统上表现出强劲的呈递。为验证这一点，我们构建了表达MYC或MYCN cDNA的UW228和ONS76髓母细胞瘤细胞系，以GFP作为对照，并通过Western印迹和qPCR验证了过表达。我们通过流式细胞术评估了HLA-I蛋白的一致性。使用核糖体测序和RNA测序识别活跃翻译的基因组区域和mRNA转录本水平。完成HLA-I免疫肽组学以识别因MYC(N)表达而表面呈递增加的非经典肽。我们成功验证了MYC(N)过表达，并证明了免疫肽组学分析所需的HLA-I表达。测序数据证实MYC(N)驱动特定非经典肽uORF的翻译，显示高风险髓母细胞瘤模型中免疫肽组复杂性增加。这些结果广泛支持MYC(N)在驱动非生产性肽通量中的作用。本研究的完成将识别与MYC(N)相关的新抗原，为开发髓母细胞瘤特异性免疫疗法提供关键信息，从而改善患者预后。未来研究将探讨MYC(N)对蛋白酶体功能和BAG6复合物的影响，后者负责调控非经典翻译产物的蛋白酶体降解。还将进行通路分析，比较基因家族表达并识别上调和下调的生物学功能。
查看英文原文 English abstract
Medulloblastoma, the most common malignant brain tumor typically found in children ages 0-9, comprises four subgroups, each with distinct molecular characteristics. Children with MYC or MYCN amplifications, which occur in Group 3 and Sonic Hedgehog subgroups, respectively, face poor survival rates and high metastasis. MYC and MYCN, both DNA-binding transcription factors, drive oncogenesis by promoting rapid cell division. This study investigates how MYC(N) upregulation stimulates the production of immunogenic neoantigens from non-canonical peptides, which may serve as novel targets for immunotherapy. Prior work shows post-transcriptional control is a critical component of MYC biology, with Group 3 tumors exhibiting significant protein-RNA dyssynchrony. Intriguingly, MYC preferentially drives the translation of upstream open reading frames (uORFs), which are non-canonical peptides that are largely unstable but exhibit robust presentation on the MHC-I antigen system.To test this, we engineered UW228 and ONS76 medulloblastoma cell lines to express MYC or MYCN cDNAs using GFP as a control and verified overexpression via western blotting and qPCR. We assessed HLA-I protein uniformity via flow cytometry. Ribosome and RNA sequencing were used to identify actively translated genomic regions and mRNA transcript levels. HLA-I immunopeptidomics was completed to identify non-canonical peptides with increased surface presence due to MYC(N) expression.We successfully verified MYC(N) overexpression and demonstrated the required HLA-I expression for immunopeptidomic analysis. The sequencing data confirmed that MYC(N) drives the translation of specific non-canonical peptides uORFs, showing increased immunopeptidome complexity in high-risk medulloblastoma models. These results are broadly supportive of MYC(N)'s role in driving the flux of non-productive peptides.Completion of this research will identify novel antigens linked to MYC(N), offering critical information for the development of medulloblastoma-specific immunotherapies to improve outcomes for affected patients. Future research will investigate MYC(N)'s impact on proteasome function and the BAG6 complex, which is responsible for regulating proteasomal degradation of non-canonical translation products. Pathway analyses will also be conducted to compare gene family expression and identify upregulated and downregulated biological functions.
利益披露 Disclosure
J. Faulkner, None..
A. Dasgupta, None.