Song Jintian, Chen Yigui, Yu Hui, Zheng Liang, Wang Yi, Li Dan
Department of Gastroenterology, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian Province, China.
Department of Abdominal Oncology, Clinical Oncology School of Fujian Medical University, Fujian Cancer Hospital, Fuzhou, 350014, Fujian Province, China.
J Cancer. 2023 May 21;14(9):1515-1530. doi: 10.7150/jca.84048. eCollection 2023.
The mechanism underlying cisplatin resistance in colorectal carcinoma (CRC) has not yet been elucidated. This study is aimed to illustrate the indispensable role of proline-rich acidic protein 1 (PRAP1) in cisplatin-resistant CRC. Cell viability and apoptosis were monitored using cell counting kit-8 and flow cytometry. Immunofluorescence and morphological analysis were used to determine mitotic arrest in cells. drug resistance was evaluated using a tumor xenograft assay. PRAP1 was highly expressed in cisplatin-resistant CRC. PRAP1-upregulation in HCT-116 cells increased chemoresistance to cisplatin, whereas RNAi-mediated knockdown of PRAP1 sensitized cisplatin-resistant HCT-116 cells (HCT-116/DDP) to cisplatin. PRAP1-upregulation in HCT-116 cells hindered mitotic arrest and the formation of mitotic checkpoint complexes (MCC), followed by an increase in multidrug-resistant proteins such as p-glycoprotein 1 and multidrug resistance-associated protein 1, while PRAP1-knockdown in HCT-116/DDP cells partly restored colcemid-induced mitotic arrest and MCC assembly, resulting in decreased multidrug-resistant protein levels. PRAP1 downregulation-mediated sensitization to cisplatin in HCT-116/DDP cells was abolished by the inhibition of mitotic kinase activity by limiting MCC assembly. Additionally, PRAP1-upregulation increased cisplatin-resistance in CRC . Mechanistically, PRAP1 increased the expression of mitotic arrest deficient 1 (MAD1), that competitively binds to mitotic arrest deficient 2 (MAD2) in cisplatin-resistant CRC cells, leading to failed assembly of MCC and subsequent chemotherapy resistance. PRAP1-overexpression caused cisplatin resistance in CRC. Possibly, PRAP1 induced an increase in MAD1, which competitively interacted with MAD2 and subsequently restrained the formation of MCC, resulting in CRC cells escape from the supervision of MCC and chemotherapy resistance.
结直肠癌（CRC）中顺铂耐药的潜在机制尚未阐明。本研究旨在阐明富含脯氨酸的酸性蛋白1（PRAP1）在顺铂耐药CRC中的不可或缺作用。使用细胞计数试剂盒-8和流式细胞术监测细胞活力和凋亡。采用免疫荧光和形态学分析来确定细胞中的有丝分裂停滞。使用肿瘤异种移植试验评估耐药性。PRAP1在顺铂耐药的CRC中高表达。HCT-116细胞中PRAP1的上调增加了对顺铂的化疗耐药性，而RNAi介导的PRAP1敲低使顺铂耐药的HCT-116细胞（HCT-116/DDP）对顺铂敏感。HCT-116细胞中PRAP1的上调阻碍了有丝分裂停滞和有丝分裂检查点复合物（MCC）的形成，随后增加了多药耐药蛋白如P-糖蛋白1和多药耐药相关蛋白1的表达，而HCT-116/DDP细胞中PRAP1的敲低部分恢复了秋水仙酰胺诱导的有丝分裂停滞和MCC组装，导致多药耐药蛋白水平降低。通过限制MCC组装抑制有丝分裂激酶活性，消除了HCT-116/DDP细胞中PRAP1下调介导的对顺铂的敏感性。此外，PRAP1的上调增加了CRC中的顺铂耐药性。从机制上讲，PRAP1增加了有丝分裂停滞缺陷蛋白1（MAD1）的表达，其在顺铂耐药的CRC细胞中与有丝分裂停滞缺陷蛋白2（MAD2）竞争性结合，导致MCC组装失败和随后的化疗耐药。PRAP1的过表达导致CRC中的顺铂耐药。可能是PRAP1诱导MAD1增加，其与MAD2竞争性相互作用，随后抑制MCC的形成，导致CRC细胞逃避MCC的监督和化疗耐药。
