Colon cancer is a therapy-resistant cancer with a low 5-year survival frequency. The drug 5-fluorouracil (5-FU) has been used as a first-line therapy in metastatic colon cancer in combination with leucovorin or oxaliplatin with a >40% resistance rate. High CysLT₁R expression in tumors is associated with poor survival of colon cancer patients. We sought to examine the role of CysLT₁R in 5-FU resistance and established 5-FU-resistant (5-FU-R) colon cancer cells. These 5-FU-R-cells expressed increased levels of CysLT₁R and showed increased survival and migration compared to nonresistant cells. Increases in thymidylate synthase and active β-catenin were also observed in the 5-FU-R-cells. LTD₄/CysLT₁R signaling was further increased and abolished after CYSLTR1 CRISPR-Cas9-knockdown and reduced in CysLT₁R-doxycycline-knockdown experiments and CysLT₁R-antagonist montelukast/5-FU-treated cells. Montelukast and 5-FU resulted in synergistic effects by reducing HT-29 cell and 5-FU-R-HT-29 cell migration and zebrafish xenograft metastasis. An increase in the stem cell markers in 5-FU-R-cells and 5-FU-R-cell-derived colonospheres and in CysLT₁R-Dox-knockdown cells increased colonosphere formation and stem cell markers was noticed after 5-FU treatment. IL-4-mediated stemness in both HT-29-colonospheres and 5-FU-R-cell derived colonospheres was abolished by montelukast or montelukast + 5-FU-treatment. Targeting CysLT₁R signaling by montelukast might reverse drug resistance and decrease resistance-derived stemness in colon cancer patients.

结肠癌是一种具有5年生存率较低的耐治疗性癌症。5-氟尿嘧啶（5-FU）药物与亚叶酸或奥沙利铂联合用于转移性结肠癌的一线治疗，耐药率> 40％。肿瘤中高CysLT ₁ R表达与结肠癌患者生存不良有关。我们试图检查CysLT ₁ R在5-FU耐药中的作用，并建立了5-FU耐药（5-FU-R）结肠癌细胞。与非耐药细胞相比，这些5-FU-R细胞表达的CysLT ₁ R水平升高，并且存活和迁移增加。在5-FU-R细胞中还观察到胸苷酸合酶和活性β-连环蛋白的增加。LTD ₄ / CysLT ₁CYSLTR1 CRISPR-Cas9敲低后，R信号进一步增加和废除，在CysLT ₁ R-多西环素敲低实验和CysLT ₁ R拮抗剂孟鲁司特/ 5-FU处理的细胞中，R信号减少。孟鲁司特和5-FU通过减少HT-29细胞和5-FU-R-HT-29细胞迁移以及斑马鱼异种移植的转移而产生协同作用。5-FU处理后5-FU-R细胞和5-FU-R细胞来源的结肠球以及CysLT ₁ R-Dox-nockdown细胞中干细胞标志物的增加，增加了结肠球的形成，并注意到干细胞标志物。孟鲁司特或孟鲁司特+ 5-FU处理消除了HT-29结肠球和5-FU-R细胞来源的结肠球中IL-4介导的干性。靶向CysLT ₁孟鲁司特的R信号传导可能会逆转结肠癌患者的耐药性并降低耐药性干细胞。