Kim Soo Young, Kim Seok-Mo, Chang Ho-Jin, Kim Bup-Woo, Lee Yong Sang, Park Cheong Soo, Park Ki Cheong, Chang Hang-Seok
Thyroid Cancer Center, Gangnam Severance Hospital, Department of Surgery, Yonsei University College of Medicine, Seoul, 120-720, South Korea.
Department of Surgery, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea.
BMC Cancer. 2018 Oct 4;18(1):956. doi: 10.1186/s12885-018-4854-z.
In the last decade, several tyrosine kinase inhibitors (TKIs), which disrupt pathways involved in the proliferation and tumorigenesis of thyroid cancer, have been extensively studied. Two different TKIs, lenvatinib and sorafenib, were recently approved by both the US FDA and European Medicine Agency. Until date, the duration of the TKI response is not sufficient and resistance eventually occurs. The goal of this study was to investigate a new treatment protocol, SoLAT, using sorafenib and lenvatinib alternatively on refractory thyroid cancer.
Patient-derived aggressive papillary thyroid cancer (PTC) cell lines from patients with biochemical and histologically proven aggressive RAI-refractory papillary thyroid cancer were exposed to sorafenib and lenvatinib alternatively. Human thyroid cancer cell xenografts were obtained by injecting patient-derived aggressive PTC cell lines into the flank of female BALB/c nude mice. Tumor-bearing mice were treated with sorafenib and lenvatinib alternatively. Cell viability assay, immunofluorescence analysis, confocal imaging, immunoblot analysis, flow cytometry analysis of cell cycle and a tube formation assay were performed.
SoLAT was more effective for advanced PTC cell lines than individual treatment. Immunoblot analysis showed that SoLAT markedly increased levels of cell cycle inhibitors (p53 and p21), and pro-apoptotic factors (Apaf-1 and cleaved caspase 3) and decreased levels of positive cell cycle regulators (cyclin D1, CDK4, CDK6) and anti-apoptotic factors (p-NFκB, Bcl-2). Increased sub-G/G population was observed in the SoLAT group, leading to apoptosis, cell cycle arrest, and strong inhibition of advanced PTC cell viability. SoLAT reduced the level of EMT markers such as vimentin, E-cadherin, Snail and Zeb1 by FGFR inhibition. In the xenograft model, individual treatment with sorafenib or lenvatinib did not markedly suppress patient-derived aggressive PTC cell xenograft tumors, whereas SoLAT significantly suppressed the proliferation of these tumors.
SoLAT was more effective than individual treatment with sorafenib or lenvatinib in inhibiting PTC progression by inducing cell cycle arrest. Studies using both in vitro cell culture and an in vivo xenograft model provided evidence of tumor shrinkage with SoLAT. We suggest that these effects may be due to reduced EMT-mediated drug resistance in the aggressive PTC model.
在过去十年中，几种酪氨酸激酶抑制剂（TKIs）已得到广泛研究，这些抑制剂可破坏参与甲状腺癌增殖和肿瘤发生的信号通路。两种不同的TKIs，乐伐替尼和索拉非尼，最近已获得美国食品药品监督管理局（FDA）和欧洲药品管理局的批准。迄今为止，TKI治疗的持续时间并不足够，最终会出现耐药性。本研究的目的是探究一种新的治疗方案SoLAT，即交替使用索拉非尼和乐伐替尼治疗难治性甲状腺癌。
从生化和组织学证实为侵袭性放射性碘难治性乳头状甲状腺癌患者中获取患者来源的侵袭性乳头状甲状腺癌（PTC）细胞系，将其交替暴露于索拉非尼和乐伐替尼。通过将患者来源的侵袭性PTC细胞系注射到雌性BALB/c裸鼠的侧腹获得人甲状腺癌细胞异种移植模型。对荷瘤小鼠交替给予索拉非尼和乐伐替尼治疗。进行细胞活力测定、免疫荧光分析、共聚焦成像、免疫印迹分析、细胞周期流式细胞术分析和管形成试验。
SoLAT方案对晚期PTC细胞系的疗效优于单一治疗。免疫印迹分析表明，SoLAT显著增加细胞周期抑制剂（p53和p21）以及促凋亡因子（Apaf-1和裂解的半胱天冬酶3）的水平，并降低细胞周期正向调节因子（细胞周期蛋白D1、细胞周期蛋白依赖性激酶4、细胞周期蛋白依赖性激酶6）和抗凋亡因子（磷酸化核因子κB、Bcl-2）的水平。在SoLAT组中观察到亚G1/G1期细胞群增加，导致细胞凋亡、细胞周期停滞，并强烈抑制晚期PTC细胞活力。SoLAT通过抑制FGFR降低了波形蛋白、E-钙黏蛋白、Snail和Zeb1等上皮-间质转化（EMT）标志物的水平。在异种移植模型中，单独使用索拉非尼或乐伐替尼治疗并未显著抑制患者来源的侵袭性PTC细胞异种移植瘤，而SoLAT显著抑制了这些肿瘤的增殖。
SoLAT方案在诱导细胞周期停滞从而抑制PTC进展方面比单独使用索拉非尼或乐伐替尼更有效。使用体外细胞培养和体内异种移植模型的研究均提供了SoLAT方案使肿瘤缩小的证据。我们认为这些作用可能归因于侵袭性PTC模型中EMT介导的耐药性降低。
