Bcl-2 Family Proteins Contribute to Apoptotic Resistance in Lung Cancer Multicellular Spheroids
Bcl-2 Family Proteins Contribute to Apoptotic Resistance in Lung Cancer Multicellular Spheroids
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DOI：
10.1165/rcmb.2008-0320oc
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发表时间：
2009-07-01
影响因子：
6.4
通讯作者：
Broaddus, V. Courtney
中科院分区：
文献类型：
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作者：
Yang, Tsung-Ming;Barbone, Dario;Broaddus, V. Courtney
已发现使用蛋白酶体抑制剂硼替佐米的组合疗法在单层生长的癌细胞中诱导协同凋亡;然而，三维球状体培养可能是实体瘤（如肺癌）中发现的多细胞耐药性的更好模型。我们在A549肺癌细胞的单层和球状体中测试了使用硼替佐米与TNF相关凋亡诱导配体（TRAIL）的组合凋亡策略。事实上，硼替佐米加TRAIL诱导A549细胞生长为单层协同凋亡，但对A549细胞生长为三维多细胞球体几乎没有影响。球状体的获得性耐药性不是由于扩散限制、生存途径（例如NF-κ B或PI 3 K/Akt/mTOR）或FLIP（Fas相关死亡结构域样IL-1 β转化酶抑制蛋白，简称）的上调。然后，我们研究了Bcl-2家族的抗凋亡和促凋亡蛋白的作用。当细胞形成球状体时，抗凋亡Bcl-2增加，而抗凋亡Mcl-1减少。ABT-737是一种抑制Bcl-2但不抑制Mcl-1的小分子，可消除A549球体对硼替佐米加TRAIL的多细胞抗性。在另一种肺癌细胞系H1299中，球状体中多细胞耐药的获得也伴随着Bc 1 -2的增加和Mcl-1的减少。然而，在H1299球状体中，与A549相比，Mcl-1仍然较高，并且Mcl-1敲除在消除多细胞抗性方面比ABT-737更有效。我们的研究表明，Bcl-2家族蛋白的平衡有助于球体的获得性多细胞耐药，并提出了一个可能的目标，以改善肺癌对硼替佐米治疗的反应。
Combinatorial therapies using the proteasome inhibitor, bortezomib, have been found to induce synergistic apoptosis in cancer cells grown as monolayers; however, three-dimensional spheroid culture may be a better model for the multicellular resistance found in solid tumors, such as lung cancer. We tested the combinatorial apoptotic strategy of using bortezomib together with TNF-related apoptosis-inducing ligand (TRAIL), both in monolayers and in spheroids of A549 lung cancer cells. Indeed, bortezomib plus TRAIL induced synergistic apoptosis in A549 cells grown as monolayers, but had little effect on A549 cells grown as three-dimensional multicellular spheroids. The acquired resistance of spheroids was not due to a limitation of diffusion, to survival pathways, such as NF-kappa B or PI3K/Akt/mTOR, or to the up-regulation of FLIPs (Fas-associated death domain-like IL-1 beta-converting enzyme inhibitory protein, short). We then investigated a role for the Bcl-2 family of anti- and proapoptotic proteins. When cells formed spheroids, antiapoptotic Bcl-2 increased, whereas antiapoptotic Mcl-1 decreased. ABT-737, a small molecule that inhibits Bcl-2, but not Mcl-1, abolished the multicellular resistance of A549 spheroids to bortezomib plus TRAIL. In another lung cancer cell line, H1299, acquisition of multicellular resistance in spheroids was also accompanied by an increase in Bc1-2 and decrease in Mcl-1. In H1299 spheroids compared with those of A549, however, Mcl-1 remained higher, and Mcl-1 knockdown was more effective than ABT-737 in removing multicellular resistance. Our study suggests that the balance of Bcl-2 family proteins contributes to the acquired multicellular resistance of spheroids, and suggests a possible target for improving the response of lung cancer to bortezomib therapies.