背景:耐药性是影响结肠癌患者化疗疗效的重要因素。然而,诊断肿瘤细胞耐药性的临床标志物不仅数量少,但特异性也很低,肿瘤细胞耐药的作用机制尚不清楚。
方法:使用癌症基因组图谱(TCGA)和基因型-组织表达泛癌症数据分析二肽酶1(DPEP1)表达。使用R软件中的生存包进行生存分析以评估DPEP1表达在结肠癌中的预后价值。采用相关性和维恩分析来鉴定关键基因。免疫组织化学,westernblot,qRT-PCR,免疫共沉淀,并进行了双荧光素酶报告基因实验,以探索DPEP1和Achaetescute-like2(ASCL2)之间的潜在关联。MTT法评价DPEP1和ASCL2在结肠癌耐药中的作用。
结果:DPEP1在结肠癌组织中高表达。DPEP1表达与疾病特异性生存率呈负相关,但与总体生存率无关。生物信息学分析和实验表明,DPEP1和ASCL2在结肠癌组织中的表达呈显著正相关。机制研究表明,DPEP1通过抑制ASCL2蛋白泛素化介导的降解增强其稳定性。反过来,ASCL2充当转录因子以激活DPEP1基因的转录活性并增强其表达。此外,DPEP1还可以增强结肠癌干细胞标志物(LGR5,CD133和CD44)的表达,这增强了结肠癌细胞对化疗药物的耐受性。
结论:我们的发现表明,DPEP1通过与ASCL2形成正反馈回路来增强肿瘤细胞的干性,从而改善对化疗药物的耐药性。
Drug resistance is an important factor affecting the efficacy of chemotherapy in patients with colon cancer. However, clinical markers for diagnosing drug resistance of tumor cells are not only a few in number, but also low in specificity, and the mechanism of action of tumor cell drug resistance remains unclear.
Dipeptidase 1 (DPEP1) expression was analyzed using the cancer genome atlas (TCGA) and genotype-Tissue Expression pan-cancer data. Survival analysis was performed using the survival package in R software to assess the prognostic value of DPEP1 expression in colon cancer. Correlation and Venn analyses were adopted to identify key genes. Immunohistochemistry, western blot, qRT-PCR, Co-immunoprecipitation, and dual-luciferase reporter experiments were carried out to explore the underlying associations between DPEP1 and Achaete scute-like 2 (
ASCL2). MTT assays were used to evaluate the role of DPEP1 and
ASCL2 in colon cancer drug resistance.
DPEP1 was highly expressed in colon cancer tissues. DPEP1 expression correlated negatively with disease-specific survival but not with overall survival. Bioinformatics analysis and experiments showed that the expressions of DPEP1 and
ASCL2 in colon cancer tissues were markedly positively correlated. Mechanistic research indicated that DPEP1 enhanced the stability of protein ASCL2 by inhibiting its ubiquitination-mediated degradation. In turn,
ASCL2 functioned as a transcription factor to activate the transcriptional activity of the DPEP1 gene and boost its expression. Furthermore, DPEP1 also could enhance the expression of colon cancer stem cell markers (LGR5, CD133, and CD44), which strengthened the tolerance of colon cancer cells to chemotherapy drugs.
Our findings reveal that the DPEP1 enhances the stemness of tumor cells by forming a positive feedback loop with
ASCL2 to improve resistance to chemotherapy drugs.