School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea.
School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
Anticancer Res. 2022 May;42(5):2433-2442. doi: 10.21873/anticanres.15722.
BACKGROUND/AIM: The over-expression of P-glycoprotein (P-gp) is a major mechanism underlying multidrug resistance (MDR). Co-treatment with Janus kinase 2 (Jak2) inhibitors sensitizes P-gp-over-expressing drug-resistant cancer cells. In this study, we evaluated pacritinib, a Jak2 inhibitor currently in phase III clinical trials.
Microscopic observation, cell viability assay, colony forming assay, rhodamine uptake tests, annexin V analyses, fluorescence-activated cell sorting (FACS), and western-blot analysis were performed to further investigate the mechanism of action.
We found that pacritinib reduced cell viability, induced G arrest, and upregulated early apoptosis when administered to P-gp-over-expressing resistant KBV20C cells with vincristine (VIC). Moreover, apoptosis and G arrest in VIC-pacritinib-treated cells were involved in the upregulation of pH2AX expression. Pacritinib had an approximately 2-fold higher P-gp-inhibitory activity than the dimethyl sulfoxide (DMSO)-treated control, indicating that VIC-pacritinib sensitization involves the P-gp-inhibitory effects of pacritinib. Similar to VIC, other antimitotic drugs (vinorelbine, vinblastine, and eribulin) could also sensitize against KBV20C cells by co-treatment with pacritinib. Furthermore, comparison of pacritinib with previously characterized Jak2 inhibitors revealed that the VIC-pacritinib combination had sensitization effects similar to those of VIC- CEP-33779 or VIC-NVP-BSK805 combinations at lower doses in KBV20C cells. Generally, Jak2 inhibitor and VIC co-treatment sensitized P-gp-over-expressing resistant cancer cells by inducing early apoptosis.
Collectively, pacritinib, induced G arrest, reduced cell viability, had high P-gp inhibitory activity, and upregulated the expression of pH2AX when used in combination with VIC. As pacritinib is a Jak2 inhibitor currently in phase III clinical trials, our findings may facilitate the application of this co-treatment in patients with MDR cancer.
背景/目的：P-糖蛋白（P-gp）的过度表达是多药耐药（MDR）的主要机制。联合使用 Janus 激酶 2（Jak2）抑制剂可使 P-gp 过表达的耐药癌细胞敏感。在这项研究中，我们评估了 Jak2 抑制剂帕克里替尼（pacritinib），它目前正在进行 III 期临床试验。
通过显微镜观察、细胞活力测定、集落形成测定、罗丹明摄取试验、膜联蛋白 V 分析、荧光激活细胞分选（FACS）和 Western blot 分析进一步研究其作用机制。
我们发现帕克里替尼与长春新碱（VIC）联合应用于 P-gp 过表达的耐药 KBV20C 细胞时，可降低细胞活力、诱导 G1 期阻滞，并上调早期凋亡。此外，VIC-帕克里替尼处理细胞中的凋亡和 G1 期阻滞涉及 pH2AX 表达的上调。与二甲基亚砜（DMSO）处理对照组相比，帕克里替尼对 P-gp 的抑制活性约高 2 倍，表明 VIC-帕克里替尼的增敏作用涉及帕克里替尼对 P-gp 的抑制作用。与 VIC 类似，其他抗有丝分裂药物（长春瑞滨、长春碱和埃博霉素）与帕克里替尼联合使用也能使 KBV20C 细胞敏感。此外，与以前表征的 Jak2 抑制剂相比，帕克里替尼与 VIC 的组合在 KBV20C 细胞中以较低剂量具有与 VIC-CEP-33779 或 VIC-NVP-BSK805 组合相似的增敏作用。一般来说，Jak2 抑制剂和 VIC 联合用药通过诱导早期凋亡使 P-gp 过表达的耐药癌细胞敏感。
总之，帕克里替尼与 VIC 联合使用时，可诱导 G1 期阻滞，降低细胞活力，具有高 P-gp 抑制活性，并上调 pH2AX 的表达。由于帕克里替尼是一种目前正在进行 III 期临床试验的 Jak2 抑制剂，我们的研究结果可能有助于将这种联合治疗应用于 MDR 癌症患者。
