Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Key Laboratory of Mental Disorders, Department of Anatomy and Histoembryology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China.
Department of General Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China.
Mol Med Rep. 2021 Mar;23(3). doi: 10.3892/mmr.2021.11826. Epub 2021 Jan 5.
Colorectal cancer (CRC) has a significant burden on healthcare systems worldwide, and is associated with high morbidity and mortality rates in patients. In 2020, the estimated new cases of colon cancer in the United States are 78,300 in men and 69,650 in women. Thus, developing effective and novel alternative agents and adjuvants with reduced side effects is important to reduce the lethality of the disease and improve the quality of life of patients. Melatonin, a pineal hormone that possesses numerous physiological functions, including anti‑inflammatory and antitumor activities, can be found in various tissues, including the gastrointestinal tract. Melatonin exerts anticarcinogenic effects via various mechanisms; however, the identified underlying molecular mechanisms do not explain the full breadth of anti‑CRC effects mediated by melatonin. MicroRNAs (miRs) serve critical roles in tumorigenesis, however, whether melatonin can inhibit CRC by regulating miRs is not completely understood. In the present study, the roles and mechanism underlying melatonin in CRC were investigated. The proliferation of human CRC cells was tested by CCK8, EDU and colony formation assay. The apoptosis of cancer cells was detected by flow cytometry and western blotting. A xenograft mouse model was constructed and the proliferation and apoptosis of tumor tissue was detected by Ki‑67 and TUNEL staining assay respectively. Reverse transcription‑quantitative PCR and western blotting were performed to measure the regulation of miRs on mRNA, and the dual‑luciferase report analysis experiment was used to verify the direct target genes of miRs. Compared with the control group, melatonin inhibited viability and proliferation, and induced apoptosis in CRC cells. Additionally, the effect of melatonin in a xenograft mouse model was assessed. Compared with the control group, melatonin significantly enhanced the expression levels of the miR‑34a/449a cluster, reduced CRC cell proliferation and viability, and increased CRC cell apoptosis. Finally, the dual‑luciferase reporter assay indicated that Bcl‑2 and Notch1 were the target mRNAs of the miR‑34a/449a cluster. To the best of our knowledge, the present study was the first to suggest that melatonin inhibited proliferation and viability, and promoted apoptosis in CRC cells via upregulating the expression of the miR‑34a/449a cluster and . Therefore, melatonin may serve as a potential therapeutic for CRC.
结直肠癌（CRC）在全球医疗体系中负担沉重，并且与患者的高发病率和死亡率相关。2020 年，美国估计男性结肠癌新发病例为 78300 例，女性为 69650 例。因此，开发具有降低副作用的有效和新型替代药物和佐剂对于降低疾病的致死率和提高患者的生活质量非常重要。褪黑素是一种松果腺激素，具有多种生理功能，包括抗炎和抗肿瘤活性，可存在于包括胃肠道在内的各种组织中。褪黑素通过多种机制发挥抗癌作用；然而，已确定的潜在分子机制并不能解释褪黑素介导的抗 CRC 作用的全部范围。microRNAs（miRs）在肿瘤发生中起关键作用，然而，褪黑素是否可以通过调节 miRs 来抑制 CRC 尚不完全清楚。在本研究中，研究了褪黑素在 CRC 中的作用和机制。通过 CCK8、EDU 和集落形成实验检测人 CRC 细胞的增殖。通过流式细胞术和蛋白质印迹法检测癌细胞的凋亡。构建异种移植小鼠模型，通过 Ki-67 和 TUNEL 染色实验分别检测肿瘤组织的增殖和凋亡。通过逆转录-定量 PCR 和蛋白质印迹法测量 miR 对 mRNA 的调控，并用双荧光素酶报告分析实验验证 miR 的直接靶基因。与对照组相比，褪黑素抑制 CRC 细胞的活力和增殖，并诱导其凋亡。此外，评估了褪黑素在异种移植小鼠模型中的作用。与对照组相比，褪黑素显著增强了 miR-34a/449a 簇的表达水平，降低了 CRC 细胞的增殖和活力，并增加了 CRC 细胞的凋亡。最后，双荧光素酶报告分析实验表明，Bcl-2 和 Notch1 是 miR-34a/449a 簇的靶 mRNA。据我们所知，本研究首次表明，褪黑素通过上调 miR-34a/449a 簇的表达来抑制 CRC 细胞的增殖和活力，并促进其凋亡。因此，褪黑素可能作为 CRC 的一种潜在治疗药物。
