CAFs外泌体通过上调ABCB5诱导乳腺癌细胞化疗耐药

目的:探讨肿瘤相关成纤维细胞(CAFs)诱导乳腺癌细胞耐药及其作用机制。方法:从临床样本中分离培养CAFs,获取条件培养基,并纯化外泌体。使用CAFs条件培养基或CAFs外泌体与CD44+的乳腺癌干细胞(CSCs)和CD44-的非干细胞亚群共培养,并用5氟尿嘧啶(5-FU)处理共培养的细胞,通过成球实验和CCK8实验检测细胞的自我更新能力和存活能力。抑制细胞中ABCB5的表达,检测5-FU对细胞存活能力的影响。结果:CAFs条件培养或外泌体处理的CSCs自我更新能力和对5-FU的耐药能力更强,成球能力和对5-FU耐药性上升约1.5-2倍。CAFs外泌体可提高CSCs中ABCB5的表达水平约4-5倍,抑制ABCB5可降低CSCs的耐药性至原来的约60-80%。结论:CAFs通过旁分泌外泌体增强CSCs的自我更新能力并通过上调CSCs中ABCB5的表达水平促进其对化疗药物的抵抗。

CAFs-exosomes Induce Chemoresistance of Breast Cancer Cells via Upregulating ABCB5

ABSTRACT Objective: To explore drug resistance and its underlying mechanisms of breast cancer cells induced by carcinoma-as- sociated fibroblasts (CAFs). Methods: CAFs were isolated from clinical samples and cultured to produce conditioned medium (CM) fol- lowed by purification of exosomes. Sphere-formation assay and CCK8 assay were performed to detect the capacity of self-renewing and survival of CD44⁺ breast cancer stem cells (CSCs) and CD44^- non-CSCs cocultured with CAFs-CM or exosomes and treated with 5-FU. The survival ability of CSCs was detected after knocking down of ABCB5. Results: Treatment with CAFs-CM or exosomes enhanced the capacity of self-renewing and resistance to 5-FU of CSCs, sphere formation ability and chemoresistance to 5-FU increased about 1.5 to 2 folds. CAFs-exosomes increased the expression of ABCB5 of CSCs to about 4 to 5 folds and knockdown of ABCB5 decreased its drug resistance to 60-80% of that of normal ABCB5 expression groups. Conclusion: CAFs-exosomes enhanced the capacity of self-renewing of CSCs and upregulated the expression of ABCB5 thus contributing to its resistance to chemotherapy.