Junco Jacob J, Mancha-Ramirez Anna, Malik Gunjan, Wei Sung-Jen, Kim Dae Joon, Liang Huiyun, Slaga Thomas J
aDepartment of Pharmacology bEdinburg Regional Academic Health Center, Medical Research Division, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
Melanoma Res. 2015 Apr;25(2):103-12. doi: 10.1097/CMR.0000000000000137.
Malignant melanoma is associated with a 5-year survival rate of less than 20% once metastasized. Malignant melanoma cells exhibit increased levels of autophagy, a process of intracellular digestion that allows cells to survive various stresses including chemotherapies, resulting in reduced patient survival. Autophagy can be inhibited by chemicals like chloroquine (CQ), which prevents fusion of autophagosomes to lysosomes, resulting in autophagosome accumulation in most systems. Here, we describe how tested CQ to see whether it could sensitize B16F10 metastatic mouse melanoma cells to the anticancer activities of the natural compounds ursolic acid (UA) and resveratrol (RES). CQ with UA or RES strongly and synergistically reduced the viability of B16F10 mouse melanoma and A375 human melanoma cells. Surprisingly, flow cytometry of acridine orange-stained cells showed that UA or RES in combination with CQ significantly reduced autophagosome levels. Western blotting analysis revealed that CQ plus UA or RES paradoxically increased LC3II, indicative of autophagosome accumulation. In addition, CQ plus RES synergistically decreased the levels of both autophagy initiator beclin-1 and autophagy supporter p62. These results indicate that CQ with UA or RES strongly and synergistically reduces the viability of B16F10 and A375 melanoma cells. However, studies on B16F10 cells have shown that the synergistic effect was not mediated by inhibition of autophagy induced by UA or RES. These compounds are well-tolerated in humans, and CQ has shown promise as an adjuvant therapy. These combinations may be valuable treatment strategies for melanoma.
恶性黑色素瘤一旦发生转移，其5年生存率低于20%。恶性黑色素瘤细胞的自噬水平升高，自噬是一种细胞内消化过程，可使细胞在包括化疗在内的各种应激条件下存活，从而导致患者生存率降低。自噬可被氯喹（CQ）等化学物质抑制，氯喹可阻止自噬体与溶酶体融合，导致大多数系统中自噬体积累。在此，我们描述了如何测试CQ，以观察其是否能使B16F10转移性小鼠黑色素瘤细胞对天然化合物熊果酸（UA）和白藜芦醇（RES）的抗癌活性敏感。CQ与UA或RES联合使用可强烈且协同地降低B16F10小鼠黑色素瘤细胞和A375人黑色素瘤细胞的活力。令人惊讶的是，吖啶橙染色细胞的流式细胞术分析表明，UA或RES与CQ联合使用可显著降低自噬体水平。蛋白质印迹分析显示，CQ加UA或RES反常地增加了LC3II，这表明自噬体积累。此外，CQ加RES协同降低了自噬起始因子beclin-1和自噬支持因子p62的水平。这些结果表明，CQ与UA或RES联合使用可强烈且协同地降低B16F10和A375黑色素瘤细胞的活力。然而，对B16F10细胞的研究表明，这种协同效应不是由抑制UA或RES诱导的自噬介导的。这些化合物在人体中耐受性良好，并且CQ已显示出作为辅助治疗的前景。这些联合用药可能是黑色素瘤有价值的治疗策略。
