目的:探讨rigosertib(RGS)与结直肠癌经典化疗药物联合对KRAS突变型结直肠癌的疗效及不良反应。方法:通过裸鼠皮下接种构建KRAS突变型结直肠癌模型，采用随机数字表法及随机数余数法随机分为对照组、RGS组、5－氟尿嘧啶(5－FU)组、奥沙利铂(OXA)组、伊立替康(IRI)组、5－FU+RGS组、OXA+RGS组和IRI+RGS组，观察各组小鼠体重和肿瘤体积的变化，采用免疫组化染色、原位末端标记荧光染色、Western blot法检测肿瘤组织增殖抑制及凋亡情况，通过小鼠血常规、血生化及肝脏组织切片HE染色分析化疗联合RGS的不良反应情况。采用细胞计数试剂盒8检测OXA与RGS联用对KRAS突变型结直肠癌细胞DLD1和HCT116的协同作用。结果:对照组、RGS组、5－FU组、OXA组、IRI组、5－FU+RGS组、OXA+RGS组和IRI+RGS组小鼠移植瘤均成瘤，肿瘤生长快慢不一，其中OXA+RGS组肿瘤增长较慢。到给药后55 d，OXA+RGS组的肿瘤体积倍数为37.019±8.634，均小于RGS组(77.571±15.387， P＝0.029)和OXA组(92.500±13.279， P＝0.008)，具有协同效应。免疫组化染色显示，对照组、OXA组、RGS组和OXA+RGS组小鼠移植瘤组织Ki－67指数分别为(100.0±16.8)%、(35.6±11.3)%、(54.5±18.1)%和(15.4±3.9)%，OXA+RGS组低于对照组( P＝0.014)，但与OXA组和RGS组比较差异无统计学意义(均 P>0.05)。TUNEL荧光染色结果显示，OXA+RGS组凋亡细胞荧光信号强度为3.878±0.547，高于OXA组(1.515±0.442， P＝0.005)和RGS组(1.966±0.261， P＝0.008)。Western blot检测结果显示，OXA+RGS组小鼠移植瘤组织中cleaved－PARP、cleaved－caspase 3和cleaved－caspase 8等凋亡相关蛋白表达量均高于对照组、OXA组和RGS组。裸鼠接受RGS、5－FU、OXA、IRI等单药和联合治疗后，未见明显肝肾功能损害，但OXA+RGS组白细胞为(0.385±0.215)×10 9/L，血红蛋白为(56.000±24.000)g/L，均低于对照组[分别为(5.598±0.605)×10 9/L和(153.333±2.231)g/L，均 P<0.01]。 结论:RGS与5－FU、IRI联用治疗KRAS突变型结直肠癌不能增强疗效，但与OXA联用具有更强的抗肿瘤效应。RGS单药不会对小鼠造成明显的骨髓抑制和肝肾功能损伤，但与OXA联用不良反应可能会相应增加。

Rigosertib是一种非ATP竞争性多激酶抑制剂,具有显著的抗有丝分裂和抗癌活性,可诱导多种肿瘤细胞增殖停滞和凋亡,对正常细胞增殖的影响很小.Rigosertib已作为高危骨髓增生异常综合征患者的治疗药物应用于Ⅲ期临床试验.本文就Rigosertib的分子作用机制、体内外抗肿瘤活性以及临床试验等方面的研究进展做简要综述.

Objective: Mutant KRAS, the principal isoform of RAS, plays a pivotal role in the oncogenesis of colorectal cancer by constitutively activating the RAF/MEK/ERK and PI3K/AKT pathways. Effective targeted therapies are urgently needed. We investigated whether rigosertib, a benzyl styryl sulfone RAS signaling disruptor, could selectively kill KRAS-mutant colorectal cancer cells.Methods: CCK-8 was used to determine the cell viability. Patient-derived tumor and cancer cell xenograft models were used to detect the inhibitory efficacy of rigosertib. Flow cytometry was used to evaluate the apoptosis and cell cycle progression. Apoptosis and cell cycle arrest markers were detected by Western blot. DCFH-DA was used to determine the reactive oxygen species. Immunohistochemistry staining and Western blot were performed to characterize RAS signaling markers in colorectal cancer tissues and cells. Results: Rigosertib (RGS) exhibited a cytotoxic effect against colorectal cancer cells, which was greater in KRAS-mutant cells. Furthermore, RGS induced mitotic arrest and oxidative stress-dependent apoptosis in KRAS-mutant DLD1 and HCT116 cells. Besides, RGS disrupted RAS signaling, and the inhibition of RAS/MEK/ERK was independent of cellular oxidative stress. Using patient-derived xenograft models, the response and tumor inhibition of RGS were significantly higher in the KRAS-mutant subgroup, while p-MEK, p-ERK, and p-AKT levels of RGS-treated tumors were significantly decreased. Finally, in a KRAS-mutant, chemotherapy-resistant patient-derived xenograft model, RGS showed a stronger therapeutic effect than the combination standard therapy involving fluoropyrimidine + oxaliplatin/irinotecan + bevacizumab. Conclusions: These data showed that targeting RAS signaling using RGS could be a therapeutic treatment for KRAS-mutant colorectal cancer patients.