Ando Miki, Hoyos Valentina, Yagyu Shigeki, Tao Wade, Ramos Carlos A, Dotti Gianpietro, Brenner Malcolm K, Bouchier-Hayes Lisa
Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital, and Houston Methodist Hospital, Houston, Texas, USA.
Department of Pediatrics-Hematology, Baylor College of Medicine, Houston, Texas, USA.
Cancer Gene Ther. 2014 Nov;21(11):472-482. doi: 10.1038/cgt.2014.53. Epub 2014 Oct 17.
Delivery of suicide genes to solid tumors represents a promising tumor therapy strategy. However, slow or limited killing by suicide genes and ineffective targeting of the tumor has reduced effectiveness. We have adapted a suicide system based on an inducible caspase-9 (iC9) protein that is activated using a specific chemical inducer of dimerization (CID) for adenoviral-based delivery to lung tumors via mesenchymal stromal cells (MSCs). Four independent human non-small cell lung cancer (NSCLC) cell lines were transduced with adenovirus encoding iC9, and all underwent apoptosis when iC9 was activated by adding CID. However, there was a large variation in the percentage of cell killing induced by CID across the different lines. The least responsive cell lines were sensitized to apoptosis by combined inhibition of the proteasome using bortezomib. These results were extended to an in vivo model using human NSCLC xenografts. E1A-expressing MSCs replicated Ad.iC9 and delivered the virus to lung tumors in SCID mice. Treatment with CID resulted in some reduction of tumor growth, but addition of bortezomib led to greater reduction of tumor size. The enhanced apoptosis and anti-tumor effect of combining MSC-delivered Ad.iC9, CID and bortezomib appears to be due to increased stabilization of active caspase-3, as proteasomal inhibition increased the levels of cleaved caspase-9 and caspase-3. Knockdown of X-linked inhibitor of apoptosis protein (XIAP), a caspase inhibitor that targets active caspase-3 to the proteasome, also sensitized iC9-transduced cells to CID, suggesting that blocking the proteasome counteracts XIAP to permit apoptosis. Thus, MSC-based delivery of the iC9 suicide gene to human NSCLC effectively targets lung cancer cells for elimination. Combining this therapy with bortezomib, a drug that is otherwise inactive in this disease, further enhances the anti-tumor activity of this strategy.
将自杀基因递送至实体瘤是一种很有前景的肿瘤治疗策略。然而，自杀基因的杀伤作用缓慢或有限以及对肿瘤的靶向性不佳降低了其有效性。我们采用了一种基于可诱导型半胱天冬酶-9（iC9）蛋白的自杀系统，该蛋白可通过一种特定的二聚化化学诱导剂（CID）激活，用于通过间充质基质细胞（MSC）以腺病毒为载体递送至肺肿瘤。用编码iC9的腺病毒转导四种独立的人非小细胞肺癌（NSCLC）细胞系，当通过添加CID激活iC9时，所有细胞系均发生凋亡。然而，不同细胞系中由CID诱导的细胞杀伤百分比存在很大差异。反应最不敏感的细胞系通过使用硼替佐米联合抑制蛋白酶体而对凋亡敏感。这些结果扩展至使用人NSCLC异种移植的体内模型。表达E1A的MSC复制Ad.iC9并将病毒递送至SCID小鼠的肺肿瘤。用CID治疗导致肿瘤生长有所减缓，但添加硼替佐米导致肿瘤大小进一步减小。联合使用MSC递送的Ad.iC9、CID和硼替佐米增强的凋亡和抗肿瘤作用似乎是由于活性半胱天冬酶-3的稳定性增加，因为蛋白酶体抑制增加了裂解的半胱天冬酶-9和半胱天冬酶-3的水平。凋亡抑制蛋白（XIAP）的X连锁抑制因子敲低，XIAP是一种将活性半胱天冬酶-3靶向蛋白酶体的半胱天冬酶抑制剂，也使iC9转导的细胞对CID敏感，表明阻断蛋白酶体可抵消XIAP以允许凋亡。因此，基于MSC将iC9自杀基因递送至人NSCLC可有效靶向肺癌细胞以将其清除。将这种疗法与硼替佐米联合使用，硼替佐米在该疾病中原本无活性，进一步增强了该策略的抗肿瘤活性。
