Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Gastroenterology and Hepatology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
J Transl Med. 2019 Apr 16;17(1):126. doi: 10.1186/s12967-019-1876-5.
Esophageal cancer is the sixth-leading cause of cancer-related deaths worldwide. Cancer stem cells (CSCs) are the main reason for tumor relapse in esophageal squamous cell carcinoma (ESCC). The NOTCH pathway is important in preservation of CSCs, therefore it is possible to target such cells by targeting MAML1 as the main component of the NOTCH transcription machinery.
In present study we isolated the CD44+ ESCC CSCs and designed a MAML1-targeted therapy to inhibit the NOTCH signaling pathway. CSCs were isolated using magnetic cell sorting utilizing the CD44 cell surface marker. Several stem cell markers were analyzed in the levels of protein and mRNA expression. The isolated CSCs were characterized in vivo in NUDE mice. Biological role of MAML1 was assessed in isolated CD44+ CSCs. A drug resistance assay was also performed to assess the role of MAML1 in CD44+ CSCs with 5FU resistance.
The CD44+ CSCs had ability to form tumors in NUDE mice. MAML1 silencing caused a significant decrease (p = 0.019) and ectopic expression caused a significant increase in migration of CD44+ CSCs (p = 0.012). Moreover, MAML1 silencing and ectopic expression significantly increased and decreased 5FU resistance, respectively (p < 0.05). MAML1 silencing significantly increased the number of cells in G1 phase (p = 0.008), and its ectopic expression significantly increased the number of CD44+ CSCS in S phase (p = 0.037).
MAML1 may be utilized for targeted therapy with a low side effect to eliminate the CD44+ CSCs through inhibition of canonical NOTCH pathway in ESCC patients.
食管癌是全球第六大癌症相关死亡原因。癌症干细胞（CSC）是食管鳞状细胞癌（ESCC）肿瘤复发的主要原因。NOTCH 通路在 CSC 的维持中很重要，因此通过靶向作为 NOTCH 转录机制主要成分的 MAML1 靶向 CSC 是可能的。
在本研究中，我们分离了 CD44+ ESCC CSC，并设计了一种靶向 MAML1 的治疗方法来抑制 NOTCH 信号通路。使用 CD44 细胞表面标志物通过磁细胞分选分离 CSC。在蛋白质和 mRNA 表达水平分析了几种干细胞标志物。将分离的 CSC 在裸鼠体内进行了表征。在分离的 CD44+ CSC 中评估了 MAML1 的生物学作用。还进行了耐药性测定，以评估 MAML1 在具有 5FU 耐药性的 CD44+ CSC 中的作用。
CD44+ CSC 具有在裸鼠中形成肿瘤的能力。MAML1 沉默导致迁移显著减少（p=0.019），而异位表达导致 CD44+ CSC 的迁移显著增加（p=0.012）。此外，MAML1 沉默和异位表达分别显著增加和减少了 5FU 耐药性（p<0.05）。MAML1 沉默显著增加了 G1 期细胞数量（p=0.008），而其异位表达显著增加了 S 期 CD44+ CSCS 的数量（p=0.037）。
MAML1 可用于通过抑制 ESCC 患者的经典 NOTCH 通路，利用靶向治疗具有低副作用的方法来消除 CD44+ CSC。
