Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.
Biological Center, Faculty of Marine Sciences and Technologies in Bandar Abbas, Hormozgan University, Hormozgan, Iran.
Cancer Genomics Proteomics. 2021 May-Jun;18(3):295-306. doi: 10.21873/cgp.20260.
BACKGROUND/AIM: Colorectal cancer is currently the third leading cause of cancer-related deaths and recently, alternative splicing has risen as its important regulator and potential treatment target. In the present study, we analyzed gene expression of the MBNL family of regulators of alternative splicing in various stages of colorectal cancer development, together with the MBNL-target splicing events in FOXP1 and EPB41L3 genes and tumor-related CD44 variants.
Samples of tumor tissue and non-malignant mucosa from 108 patients were collected. After RNA isolation and reverse transcription, the relative gene expression of a selected gene panel was tested by quantitative real-time PCR, followed by statistical analysis.
MBNL expression was decreased in tumor tissue compared to non-tumor mucosa. In addition, lower expression was observed for the variants of FOXP1 and EPB41L3, while higher expression in tumor tissue was detected both for total CD44 and its cancer-related variants 3 and 6. Transcript levels of the MBNL genes were not found to be related to any of the studied clinicopathological characteristics. Multiple significant associations were identified in the target gene panel, including higher transcript levels of FOXP1 and CD44v3 in patients with distant metastases and connections between recurrence-free survival and altered levels of FOXP1 and CD44v3.
Our results identified for the first-time deregulation of MBNL genes in colorectal cancer. Down-regulation of their transcripts in tumor tissue compared to matched non-tumor mucosa can lead to transition of alternative splicing patterns towards a less differentiated phenotype, which highlights the importance of alternative splicing regulation for tumor growth and propagation.
背景/目的：结直肠癌目前是癌症相关死亡的第三大主要原因，最近，选择性剪接已成为其重要的调控因子和潜在的治疗靶点。本研究分析了结直肠癌发展的各个阶段中 MBNL 家族调节性剪接因子的基因表达，以及 FOXP1 和 EPB41L3 基因及肿瘤相关 CD44 变体的 MBNL 靶标剪接事件。
收集了 108 例患者的肿瘤组织和非恶性黏膜样本。在 RNA 分离和逆转录后，通过实时定量 PCR 测试了选定基因表达谱的相对基因表达，并进行了统计分析。
与非肿瘤黏膜相比，肿瘤组织中的 MBNL 表达降低。此外，FOXP1 和 EPB41L3 的变体表达降低，而总 CD44 及其肿瘤相关变体 3 和 6 在肿瘤组织中的表达升高。MBNL 基因的转录水平与所研究的临床病理特征均无相关性。在靶基因谱中发现了多个显著关联，包括远处转移患者的 FOXP1 和 CD44v3 转录本水平较高，以及无复发生存与 FOXP1 和 CD44v3 水平改变之间的联系。
我们的研究首次确定了结直肠癌中 MBNL 基因的失调。与配对的非肿瘤黏膜相比，肿瘤组织中这些转录本的下调可能导致选择性剪接模式向分化程度较低的表型转变，这突出了选择性剪接调控对肿瘤生长和增殖的重要性。
