International Ph.D. Program for Translational Science, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan.
Department of Physiology, Pathophysiology and Immunology, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, 700000, Vietnam.
J Exp Clin Cancer Res. 2024 Apr 30;43(1):130. doi: 10.1186/s13046-024-03057-0.
Medulloblastomas (MBs) are one of the most common malignant brain tumor types in children. MB prognosis, despite improvement in recent years, still depends on clinical and biological risk factors. Metastasis is the leading cause of MB-related deaths, which highlights an unmet need for risk stratification and targeted therapy to improve clinical outcomes. Among the four molecular subgroups, sonic-hedgehog (SHH)-MB harbors clinical and genetic heterogeneity with a subset of high-risk cases. Recently, long non-coding (lnc)RNAs were implied to contribute to cancer malignant progression, but their role in MB remains unclear. This study aimed to identify pro-malignant lncRNAs that have prognostic and therapeutic significance in SHH-MB.
The Daoy SHH-MB cell line was engineered for ectopic expression of MYCN, a genetic signature of SHH-MB. MYCN-associated lncRNA genes were identified using RNA-sequencing data and were validated in SHH-MB cell lines, MB tissue samples, and patient cohort datasets. SHH-MB cells with genetic manipulation of the candidate lncRNA were evaluated for metastatic phenotypes in vitro, including cell migration, invasion, sphere formation, and expressions of stemness markers. An orthotopic xenograft mouse model was used to evaluate metastasis occurrence and survival. Finally, bioinformatic screening and in vitro assays were performed to explore downstream mechanisms.
Elevated lncRNA LOXL1-AS1 expression was identified in MYCN-expressing Daoy cells and MYCN-amplified SHH-MB tumors, and was significantly associated with lower survival in SHH-MB patients. Functionally, LOXL1-AS1 promoted SHH-MB cell migration and cancer stemness in vitro. In mice, MYCN-expressing Daoy cells exhibited a high metastatic rate and adverse effects on survival, both of which were suppressed under LOLX1-AS1 perturbation. Integrative bioinformatic analyses revealed associations of LOXL1-AS1 with processes of cancer stemness, cell differentiation, and the epithelial-mesenchymal transition. LOXL1-AS1 positively regulated the expression of transforming growth factor (TGF)-β2. Knockdown of TGF-β2 in SHH-MB cells significantly abrogated their LOXL1-AS1-mediated prometastatic functions.
This study proved the functional significance of LOXL1-AS1 in SHH-MB metastasis by its promotion of TGF-β2-mediated cancer stem-like phenotypes, providing both prognostic and therapeutic potentials for targeting SHH-MB metastasis.
成神经管细胞瘤（MBs）是儿童中最常见的恶性脑肿瘤类型之一。尽管近年来 MB 的预后有所改善，但仍取决于临床和生物学危险因素。转移是导致 MB 相关死亡的主要原因，这突显了对风险分层和靶向治疗以改善临床结果的迫切需求。在四个分子亚组中，声 Hedgehog（SHH）-MB 具有临床和遗传异质性，其中一部分是高危病例。最近，长非编码（lnc）RNAs 被暗示有助于癌症恶性进展，但它们在 MB 中的作用尚不清楚。本研究旨在确定具有 SHH-MB 预后和治疗意义的促癌 lncRNAs。
用 MYCN （SHH-MB 的遗传特征）异位表达工程化 Daoy SHH-MB 细胞系。使用 RNA 测序数据鉴定 MYCN 相关 lncRNA 基因，并在 SHH-MB 细胞系、MB 组织样本和患者队列数据集中进行验证。对具有候选 lncRNA 遗传操作的 SHH-MB 细胞进行体外转移表型评估，包括细胞迁移、侵袭、球体形成和干性标志物的表达。使用原位异种移植小鼠模型评估转移发生和存活。最后，进行生物信息学筛选和体外测定以探索下游机制。
在表达 MYCN 的 Daoy 细胞和 MYCN 扩增的 SHH-MB 肿瘤中鉴定出 lncRNA LOXL1-AS1 表达升高，与 SHH-MB 患者的生存率降低显著相关。功能上，LOXL1-AS1 促进了 SHH-MB 细胞在体外的迁移和癌症干性。在小鼠中，表达 MYCN 的 Daoy 细胞表现出高转移率和对生存的不良影响，而在 LOXL1-AS1 干扰下，这些影响均受到抑制。综合生物信息学分析显示，LOXL1-AS1 与癌症干性、细胞分化和上皮-间充质转化过程有关。LOXL1-AS1 正向调节转化生长因子（TGF）-β2 的表达。在 SHH-MB 细胞中敲低 TGF-β2 可显著阻断其 LOXL1-AS1 介导的促转移功能。
本研究通过促进 TGF-β2 介导的癌症类干细胞表型证实了 LOXL1-AS1 在 SHH-MB 转移中的功能意义，为靶向 SHH-MB 转移提供了预后和治疗潜力。
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