Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Cancer. 2019 Apr 15;125(8):1267-1280. doi: 10.1002/cncr.31935. Epub 2019 Jan 8.
Re-expression of the imprinted tumor suppressor gene DIRAS family GTPase 3 (DIRAS3) (aplysia ras homology member I [ARHI]) induces autophagy and tumor dormancy in ovarian cancer xenografts, but drives autophagic cancer cell death in cell culture. The current study explored the tumor and host factors required to prevent autophagic cancer cell death in xenografts and the use of antibodies against those factors or their receptors to eliminate dormant autophagic ovarian cancer cells.
Survival factors (insulinlike growth factor 1 [IGF-1], vascular endothelial growth factor [VEGF], and interleukin 8 [IL-8]) were detected with growth factor arrays and measured using enzyme-linked immunoadsorbent assay analysis. Phosphorylation of protein kinase B (AKT), phosphorylation of extracellular signal-regulated kinase (ERK), nuclear localization of translocation factor EB (TFEB) or forkhead box O3a (FOXo3a), and expression of microtubule-associated proteins 1A/1B light chain 3B (MAPLC3B; LC3B) were examined using Western blot analysis. The effect of treatment with antibodies against survival factors or their receptors was studied using DIRAS3-induced dormant xenograft models.
Ovarian cancer cells grown subcutaneously in nude mice exhibited higher levels of phosphorylated ERK/AKT activity and lower levels of nuclear TFEB/FOXo3a, MAPLC3B, and autophagy compared with cells grown in culture. Induction of autophagy and dormancy with DIRAS3 was associated with decreased ERK/AKT signaling. The addition of VEGF, IGF-1, and IL-8 weakened the inhibitory effect of DIRAS3 on ERK/AKT activity and reduced DIRAS3-mediated TFEB or FOXo3a nuclear localization and MAPLC3B expression in ovarian cancer cells. Treatment with antibodies against VEGF, IL-8, and IGF receptor inhibited the growth of dormant xenografts, thereby prolonging survival from 99 to >220 days (P < .05) and curing a percentage of mice.
Treatment with a combination of anti-VEGF, anti-IL-8, and anti-IGF receptor antibodies prevented the outgrowth of dormant cells and prolonged survival in a preclinical model.
重新表达印迹肿瘤抑制基因 DIRAS 家族 GTPase 3（DIRAS3）（海兔 Ras 同源物 I [ARHI]）可诱导卵巢癌异种移植物中的自噬和肿瘤休眠，但在细胞培养中会驱动自噬性癌细胞死亡。本研究探讨了预防异种移植物中自噬性癌细胞死亡所需的肿瘤和宿主因素，以及使用针对这些因素或其受体的抗体来消除休眠的自噬性卵巢癌细胞。
使用生长因子阵列检测生存因子（胰岛素样生长因子 1 [IGF-1]、血管内皮生长因子 [VEGF] 和白细胞介素 8 [IL-8]），并使用酶联免疫吸附分析进行测量。使用 Western blot 分析检测蛋白激酶 B（AKT）的磷酸化、细胞外信号调节激酶（ERK）的磷酸化、易位因子 EB（TFEB）或叉头框 O3a（FOXO3a）的核定位以及微管相关蛋白 1A/1B 轻链 3B（MAPLC3B；LC3B）的表达。使用 DIRAS3 诱导的休眠异种移植模型研究了针对生存因子或其受体的抗体治疗的效果。
与在培养中生长的细胞相比，在裸鼠皮下生长的卵巢癌细胞表现出更高水平的磷酸化 ERK/AKT 活性和更低水平的核 TFEB/FOXO3a、MAPLC3B 和自噬。DIRAS3 诱导的自噬和休眠与 ERK/AKT 信号转导的减弱有关。添加 VEGF、IGF-1 和 IL-8 减弱了 DIRAS3 对 ERK/AKT 活性的抑制作用，并降低了 DIRAS3 介导的 TFEB 或 FOXO3a 核定位和卵巢癌细胞中 MAPLC3B 的表达。使用针对 VEGF、IL-8 和 IGF 受体的抗体治疗可抑制休眠异种移植物的生长，从而将存活时间从 99 天延长至>220 天（P<.05），并治愈了一部分小鼠。
使用抗 VEGF、抗 IL-8 和抗 IGF 受体抗体的联合治疗可防止休眠细胞的生长并延长临床前模型中的存活时间。
