Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Av Bandeirantes, 3900, CEP: 14049-900, Monte Alegre, Ribeirão Preto, SP, Brazil.
Center for Cell Based Therapy and National Institute of Science and Technology in Stem Cell and Cell Therapy, Ribeirão Preto, SP, Brazil.
BMC Cancer. 2021 Mar 1;21(1):207. doi: 10.1186/s12885-021-07857-x.
Colorectal cancer (CRC) is one of the most common cancers worldwide; it is the fourth leading cause of death in the world and the third in Brazil. Mutations in the APC, DCC, KRAS and TP53 genes have been associated with the progression of sporadic CRC, occurring at defined pathological stages of the tumor progression and consequently modulating several genes in the corresponding signaling pathways. Therefore, the identification of gene signatures that occur at each stage during the CRC progression is critical and can present an impact on the diagnosis and prognosis of the patient. In this study, our main goal was to determine these signatures, by evaluating the gene expression of paired colorectal adenoma and adenocarcinoma samples to identify novel genetic markers in association to the adenoma-adenocarcinoma stage transition.
Ten paired adenoma and adenocarcinoma colorectal samples were subjected to microarray gene expression analysis. In addition, mutations in APC, KRAS and TP53 genes were investigated by DNA sequencing in paired samples of adenoma, adenocarcinoma, normal tissue, and peripheral blood from ten patients.
Gene expression analysis revealed a signature of 689 differentially expressed genes (DEG) (fold-change> 2, p< 0.05), between the adenoma and adenocarcinoma paired samples analyzed. Gene pathway analysis using the 689 DEG identified important cancer pathways such as remodeling of the extracellular matrix and epithelial-mesenchymal transition. Among these DEG, the ETV4 stood out as one of the most expressed in the adenocarcinoma samples, further confirmed in the adenocarcinoma set of samples from the TCGA database. Subsequent in vitro siRNA assays against ETV4 resulted in the decrease of cell proliferation, colony formation and cell migration in the HT29 and SW480 colorectal cell lines. DNA sequencing analysis revealed KRAS and TP53 gene pathogenic mutations, exclusively in the adenocarcinomas samples.
Our study identified a set of genes with high potential to be used as biomarkers in CRC, with a special emphasis on the ETV4 gene, which demonstrated involvement in proliferation and migration.
结直肠癌（CRC）是全球最常见的癌症之一；它是世界上第四大死亡原因，也是巴西的第三大死因。APC、DCC、KRAS 和 TP53 基因的突变与散发性 CRC 的进展有关，这些突变发生在肿瘤进展的特定病理阶段，并因此调节相应信号通路中的几个基因。因此，确定 CRC 进展过程中每个阶段发生的基因特征至关重要，并可能对患者的诊断和预后产生影响。在这项研究中，我们的主要目标是通过评估配对结直肠腺瘤和腺癌样本的基因表达来确定这些特征，以鉴定与腺瘤-腺癌阶段过渡相关的新的遗传标记。
对 10 对结直肠腺瘤和腺癌样本进行了微阵列基因表达分析。此外，通过对 10 名患者的腺瘤、腺癌、正常组织和外周血的配对样本进行 DNA 测序，研究了 APC、KRAS 和 TP53 基因的突变。
基因表达分析显示，在分析的腺瘤和腺癌配对样本之间有 689 个差异表达基因（DEG）（倍数变化>2，p<0.05）。使用 689 个 DEG 的基因通路分析鉴定了重要的癌症通路，如细胞外基质重塑和上皮-间充质转化。在这些 DEG 中，ETV4 在腺癌样本中表达最为突出，在 TCGA 数据库中的腺癌样本中也得到了进一步证实。随后针对 ETV4 的体外 siRNA 测定导致 HT29 和 SW480 结直肠细胞系的细胞增殖、集落形成和细胞迁移减少。DNA 测序分析显示 KRAS 和 TP53 基因的致病性突变仅存在于腺癌样本中。
我们的研究确定了一组具有高潜力的基因，可作为 CRC 的生物标志物，特别是 ETV4 基因，它参与了增殖和迁移。
