羧基酯脂肪酶在结直肠癌中的表达及其生物学功能

背景与目的：尽管结直肠癌的治疗水平在不断提高,但目前其疗效仍难令人满意,因此继续筛选和鉴定在结直肠癌起始和进展中发挥调控作用的关键分子,揭示其功能和机制,是开发诊疗新靶标和进一步提高结直肠癌的治疗水平的重要途经。据此,本研究首次探讨羧基酯脂肪酶（CEL）在结直肠癌中的表达水平,并初步研究其在结直肠癌中的生物学功能。方法：基于收录肿瘤组织基因表达数据的UALCAN和GEPIA在线数据库,综合分析CEL在结直肠癌和正常组织中的表达水平及其启动子甲基化水平。分别用qPCR、免疫组化、Western blot实验检测CEL在结直肠癌组织/癌旁组织与结直肠癌细胞/人正常结肠上皮细胞中的表达。通过转染特异性靶向CEL的siRNA（siCEL）,瞬时敲低人结肠癌SW620细胞中CEL的表达水平后,分别用CCK-8、平板克隆形成、Transwell迁移和侵袭实验分析CEL在结直肠癌中的基本生物学功能。结果：癌症相关数据库显示,CEL在结直肠癌组织中的表达水平明显高于正常组织（P<0.05;P<0.001）,结直肠癌组织中CEL基因的启动子甲基化水平明显低于正常组织（P<0.001）。qPCR,免疫组化和Western blot结果进一步证实CEL在结直肠癌组织中的基因和蛋白表达水平明显高于癌旁组织,在结直肠癌细胞中的水平明显高于正常结肠上皮细胞NCM460（P<0.01;P<0.001）。转染siCEL敲低SW620细胞中CEL的表达水平后,SW620细胞的生长速度、克隆形成能力、细胞迁移和侵袭能力被明显抑制（P<0.05;P<0.01;P<0.001）。结论：CEL在结直肠癌中高表达,其高表达可能与其启动子区的低甲基化有关。敲低CEL表达能显著抑制结直肠癌细胞的恶性生物学行为,表明CEL高表达促进结直肠癌恶性进展,因此,CEL有望成为结直肠癌诊断和治疗的靶标。

Expression of carboxyl ester lipase in colorectal cancer and its biological function

Background and Aims: Although the treatment of colorectal cancer has been increasingly improved, the current treatment efficacy remains unsatisfactory. Therefore, the consistent screening and identification of the critical molecules that play the regulatory roles in the initiation and progression of colorectal cancer along with revelation of their functions and actions is an important process to develop new diagnostic and therapeutic targets and eventually improve the treatment effect of colorectal cancer. Accordingly, this study was designated for the first time to investigate the expression level of carboxyl ester lipase (CEL) in colorectal cancer, and preliminarily analyze its biological function in colorectal cancer. Methods: Based on the UALCAN and GEPIA online databases containing cancer gene expression data, the expression of CEL and its promoter methylation status in colorectal cancer and normal tissues were analyzed. Then, the expression of CEL in colorectal cancer tissue/tumor adjacent normal tissue and colorectal cancer cell lines/normal human colonic epithelial cells were further determined by qPCR, immunohistochemical staining and Western blot, respectively. The expression level of CEL in human colorectal cancer SW620 cells was transiently knocked down by transfection with siRNA specifically targeting CEL (siCEL), after that, the primary biological functions of CEL in colorectal cancer were analyzed by CCK-8 assay, plate colony formation assay, Transwell migration and invasion assay, respectively. Results: The data from cancer-relevant databases showed that the expression of CEL in colorectal cancer tissues was significantly higher than that in normal tissues (P<0.05, P<0.001), and the promoter methylation level of CEL in colorectal cancer tissues was significantly lower than that in normal tissues (P<0.001). The results of qPCR, immunohistochemical staining and Western blot further confirmed that the gene and protein expression levels of CEL in colorectal cancer tissue were significantly higher than those in control tissue, and in colorectal cancer cells were significantly higher than those in normal colonic epithelial cells (P<0.01, P<0.001). In SW620 cells after CEL expression knock-down by siCEL transfection, the growth speed, colony?forming ability, as well as the migration and invasion abilities were all significantly inhibited (P<0.05, P<0.01, P<0.001). Conclusion: CEL expression is upregulated in colorectal cancer, which may be related to its hypomethylated promoter. The malignant biological behaviors of colorectal cancer cells can be inhibited by CEL knock-down, suggesting that high CEL expression promotes malignant progression of colorectal cancer. So, CEL may be a potential target for diagnosis and treatment of colorectal cancer.