Endoh D, Ishii K, Kohno K, Virgona N, Miyakoshi Y, Yano T, Ishida T
Graduate School of Food and Nutritional Sciences, Toyo University, 1-1-1 Izumino, Oura-gun, Gunma 374-0193, Japan.
Research Institute of Life Innovation, Toyo University, 1-1-1 Izumino, Oura-gun, Gunma 374-0193, Japan.
Exp Oncol. 2022 Aug;44(2):121-125. doi: 10.32471/exp-oncology.2312-8852.vol-44-no-2.18045.
Hypoxia has been noted as a key factor for induction and maintenance of cancer stemness thereby leading to therapy resistance. Three-dimensional (3D) spheroid models demonstrate a heterogeneity of hypoxic regions replicating the in vivo situation within tumors. Utilizing an established 3D spheroid model, we investigated whether extrinsic hypoxia reinforced chemoresistance in malignant pleural mesothelioma (MPM) spheroids.
Tumor spheres were generated from Meso-1 (a typical human MPM cell line) cells having high spheroid-forming ability. To induce hypoxia condition, we utilized a hypoxia chamber with regulation of O2 and CO2 levels. Cell viability was estimated by a WST-8 assay. Real-time polymerase chain reaction and Western blot were performed to evaluate the expression at mRNA and protein levels.
Compared with cells cultured in the two-dimensional monolayer model, tumor sphere cells showed elevated mRNA levels of cancer stemness markers (CD26, CD44 and ABCG2) and protein levels of the stemness and hypoxia adaptation markers (ABCG2, ALDH1A1 and HIFs). Correlating with this, 3D spheroid cells were more resistant to permetrexed and topotecan than the two-dimensional cells, indicative of their potential for hypoxic adaptation. Furthermore, significantly stronger resistance to both chemotherapeutic agents was observed in spheroid cells upon hypoxic challenge compared to spheroid cells under normoxia.
From the present data, it is concluded that hypoxia adaptation of MPM cells from tumor spheres could enhance their chemoresistance.
缺氧被认为是诱导和维持癌症干性的关键因素，从而导致治疗耐药性。三维（3D）球体模型显示了缺氧区域的异质性，可复制肿瘤内的体内情况。利用已建立的3D球体模型，我们研究了外源性缺氧是否会增强恶性胸膜间皮瘤（MPM）球体的化疗耐药性。
从具有高成球能力的Meso-1（一种典型的人MPM细胞系）细胞中生成肿瘤球体。为了诱导缺氧条件，我们使用了一个可调节氧气和二氧化碳水平的缺氧箱。通过WST-8测定法评估细胞活力。进行实时聚合酶链反应和蛋白质印迹以评估mRNA和蛋白质水平的表达。
与在二维单层模型中培养的细胞相比，肿瘤球体细胞显示癌症干性标志物（CD26、CD44和ABCG2）的mRNA水平以及干性和缺氧适应标志物（ABCG2、ALDH1A1和HIFs）的蛋白质水平升高。与此相关的是，3D球体细胞比二维细胞对培美曲塞和拓扑替康更具耐药性，表明它们具有缺氧适应的潜力。此外，与常氧条件下的球体细胞相比，缺氧刺激后的球体细胞对两种化疗药物的耐药性明显更强。
根据目前的数据，可以得出结论，肿瘤球体中的MPM细胞的缺氧适应可增强其化疗耐药性。
