背景:口腔鳞状细胞癌(OSCC)是世界范围内常见的癌症之一。缺乏特异性生物标志物和治疗靶标导致OSCC患者的延迟诊断和因此不良预后。因此,目前迫切需要确定有效的OSCC生物标志物和治疗靶点。
方法:我们建立了7,12-二甲基苯并(a)蒽烯(DMBA)诱导的OSCC的金黄地鼠致癌模型,并使用mRNA微阵列检测差异表达基因(DEGs)。使用免疫组织化学方法在OSCC临床组织微阵列中验证DEGs。进行全转录组测序以获得Lsm12的生物学功能的概述。采用PCR和测序方法研究Lsm12调控基因的可变剪接。细胞增殖,菌落形成,进行Transwell迁移和侵袭测定以及体内肿瘤形成测定以研究Lsm12和USO1的两种转录变体在OSCC细胞中的作用。
结果:Lsm12在OSCC肿瘤发生的动物模型中被鉴定为显著上调,这在临床OSCC样本中得到了验证。在配对的正常组织中,Lsm12染色阴性(91%,92/101)或弱,而在OSCC组织中,阳性率为100%,在93(93/101,92%)例中,强染色遍布整个组织。Lsm12过表达显著促进OSCC细胞生长,菌落形成,迁移和入侵能力,而Lsm12敲除在这些表型上表现出相反的趋势,并且在体内明显抑制了肿瘤的形成。此外,Lsm12过表达引起包含USO1外显子15和Lsm12敲低诱导外显子15跳跃。与外显子15缺失的USO1相比,外显子15保留的USO1显着促进了OSCC细胞的恶性表型。
结论:我们鉴定了Lsm12,一种新的肿瘤发生相关基因,作为参与OSCC肿瘤发生的重要调节因子。Lsm12是一个新的RNA剪接相关基因,可以调节USO1外显子15的可变剪接,与OSCC的发生密切相关。因此,我们的发现表明Lsm12可能是OSCC的有效生物标志物和潜在治疗靶标。
BACKGROUND: Oral squamous cell carcinoma (OSCC) is one of the common cancers worldwide. The lack of specific biomarkers and therapeutic targets leads to delayed diagnosis and hence the poor prognosis of OSCC patients. Thus, it is urgent to identify effective biomarkers and therapeutic targets for OSCC.
METHODS: We established the golden hamster carcinogenic model of OSCC induced by 7,12-dimethylbenz(a) anthrancene (DMBA) and used mRNA microarrays to detect the differentially expressed genes (DEGs). DEGs were validated in OSCC clinical tissue microarrays using immunohistochemistry method. Whole transcriptome sequencing was performed to obtain an overview of biological functions of
Lsm12. PCR assay and sequencing were employed to investigate the alternative splicing of genes regulated by Lsm12. Cell proliferation, colony formation, Transwell migration and invasion assay and in vivo tumor formation assay were performed to investigate the roles of Lsm12 and two transcript variants of USO1 in OSCC cells.
RESULTS: Lsm12 was identified to be significantly up-regulated in the animal model of OSCC tumorigenesis, which was validated in the clinical OSCC samples. In the paired normal tissues,
Lsm12 staining was negative (91%, 92/101) or weak, while in OSCC tissues, positive rate is 100% and strong staining spread over the whole tissues in 93 (93/101, 92%) cases.
Lsm12 overexpression significantly promoted OSCC cell growth, colony formation, migration and invasion abilities, while Lsm12 knockdown showed the opposite trends on these phenotypes and obviously inhibited the tumor formation in vivo. Furthermore,
Lsm12 overexpression caused the inclusion of USO1 exon 15 and
Lsm12 knockdown induced exon 15 skipping. Exon 15-retained USO1 significantly promoted the malignant phenotypes of OSCC cells when compared with the exon 15-deleted USO1.
CONCLUSIONS: We identified Lsm12, a novel tumorigenesis-related gene, as an important regulator involved in OSCC tumorigenesis. Lsm12 is a novel RNA-splicing related gene and can regulate the alternative splicing of USO1 exon 15 which was associated closely with OSCC carcinogenesis. Our findings thus provide that Lsm12 might be a potent biomarker and potential therapeutic target for OSCC.