Thakuri Pradip Shahi, Gupta Megha, Joshi Ramila, Singh Sunil, Tavana Hossein
Department of Biomedical Engineering, The University of Akron, Akron, Ohio 44325, United States.
Department of Arts and Sciences, The University of Akron, Akron, Ohio 44325, United States.
ACS Pharmacol Transl Sci. 2019 Jul 19;2(4):275-284. doi: 10.1021/acsptsci.9b00042. eCollection 2019 Aug 9.
Cancer cells often adapt to single-agent treatments with chemotherapeutics. Activation of alternative survival pathways is a major mechanism of drug resistance. A potential approach to block this feedback signaling is using combination treatments of a pair of drugs, although toxicity has been a limiting factor. Preclinical tumor models to identify mechanisms of drug resistance and determine low but effective combination doses are critical to effectively suppress tumor growth with reduced toxicity to patients. Using our aqueous two-phase system microtechnology, we developed colorectal tumor spheroids in high-throughput and evaluated resistance of cancer cells to three mitogen-activated protein kinase inhibitors (MAPKi) in long-term cyclic treatments. Our quantitative analysis showed that the efficacy of MAPKi significantly reduced over time, leading to an increase in proliferation of HCT116 colorectal cancer cells and growth of spheroids. We established that resistance was due to feedback activation of PI3K/AKT/mTOR pathway. Using high-throughput, dose-dependent combinations of each MAPKi and a PI3K/mTOR inhibitor, we identified low-dose, synergistic combinations that blocked resistance to MAPKi and effectively suppressed the growth of colorectal tumor spheroids in long-term treatments. Our approach to study drug resistance offers the potential to determine high priority treatments to test in animal models.
癌细胞常常会对单一化疗药物产生适应性。激活替代生存途径是耐药性的主要机制。尽管毒性一直是一个限制因素，但阻断这种反馈信号的一种潜在方法是使用两种药物的联合治疗。识别耐药机制并确定低剂量但有效的联合用药剂量的临床前肿瘤模型，对于有效抑制肿瘤生长同时降低对患者的毒性至关重要。利用我们的双水相系统微技术，我们高通量培养了结直肠癌肿瘤球体，并评估了癌细胞在长期循环治疗中对三种丝裂原活化蛋白激酶抑制剂（MAPKi）的耐药性。我们的定量分析表明，随着时间的推移，MAPKi的疗效显著降低，导致HCT116结肠癌细胞增殖增加以及球体生长。我们确定耐药性是由于PI3K/AKT/mTOR途径的反馈激活。通过使用每种MAPKi与PI3K/mTOR抑制剂的高通量、剂量依赖性联合用药，我们确定了低剂量的协同组合，这些组合在长期治疗中可阻断对MAPKi的耐药性，并有效抑制结肠直肠癌肿瘤球体的生长。我们研究耐药性的方法为确定在动物模型中进行测试的高优先级治疗提供了可能性。
