Draganov Dobrin, Gopalakrishna-Pillai Sailesh, Chen Yun-Ru, Zuckerman Neta, Moeller Sara, Wang Carrie, Ann David, Lee Peter P
Department of Immuno-Oncology, City of Hope, Duarte, CA, US.
Diabetes &Metabolism Research Institute, City of Hope, Duarte, CA, US.
Sci Rep. 2015 Nov 10;5:16222. doi: 10.1038/srep16222.
Overexpression of P2X7 receptors correlates with tumor growth and metastasis. Yet, release of ATP is associated with immunogenic cancer cell death as well as inflammatory responses caused by necrotic cell death at sites of trauma or ischemia-reperfusion injury. Using an FDA-approved anti-parasitic agent Ivermectin as a prototype agent to allosterically modulate P2X4 receptors, we can switch the balance between the dual pro-survival and cytotoxic functions of purinergic signaling in breast cancer cells. This is mediated through augmented opening of the P2X4/P2X7-gated Pannexin-1 channels that drives a mixed apoptotic and necrotic mode of cell death associated with activation of caspase-1 and is consistent with pyroptosis. We show that cancer cell death is dependent on ATP release and death signals downstream of P2X7 receptors that can be reversed by inhibition of NADPH oxidases-generated ROS, Ca(2+)/Calmodulin-dependent protein kinase II (CaMKII) or mitochondrial permeability transition pore (MPTP). Ivermectin induces autophagy and release of ATP and HMGB1, key mediators of inflammation. Potentiated P2X4/P2X7 signaling can be further linked to the ATP rich tumor microenvironment providing a mechanistic explanation for the tumor selectivity of purinergic receptors modulation and its potential to be used as a platform for integrated cancer immunotherapy.
P2X7受体的过表达与肿瘤生长和转移相关。然而,ATP的释放与免疫原性癌细胞死亡以及创伤或缺血再灌注损伤部位坏死性细胞死亡引起的炎症反应有关。使用美国食品药品监督管理局(FDA)批准的抗寄生虫药物伊维菌素作为变构调节P2X4受体的原型药物,我们可以改变乳腺癌细胞中嘌呤能信号传导的双重促生存和细胞毒性功能之间的平衡。这是通过增强P2X4/P2X7门控的泛连接蛋白-1通道的开放来介导的,该通道驱动与半胱天冬酶-1激活相关的混合凋亡和坏死细胞死亡模式,并且与焦亡一致。我们表明癌细胞死亡依赖于ATP释放和P2X7受体下游的死亡信号,这些信号可通过抑制NADPH氧化酶产生的活性氧、钙/钙调蛋白依赖性蛋白激酶II(CaMKII)或线粒体通透性转换孔(MPTP)来逆转。伊维菌素诱导自噬以及ATP和HMGB1(炎症的关键介质)的释放。增强的P2X4/P2X7信号传导可进一步与富含ATP的肿瘤微环境相关联,为嘌呤能受体调节的肿瘤选择性及其作为综合癌症免疫治疗平台的潜力提供了机制解释。