Oncology Research Unit, Pfizer Worldwide Research and Development, Pearl River, New York.
Clin Cancer Res. 2016 Jan 15;22(2):383-94. doi: 10.1158/1078-0432.CCR-15-1166. Epub 2015 Aug 28.
Targeted treatment of solid or liquid tumors with antibody-drug conjugates (ADCs) can lead to promising clinical benefit. The aim of the study is to investigate combination regimens of auristatin-based ADCs in preclinical models of cancer.
An auristatin-based anti-5T4 antibody conjugate (5T4-ADC) and auristatin payloads were combined with the dual PI3K/mTOR catalytic site inhibitor PF-05212384 (PF-384) or taxanes in a panel of tumor cell lines. Drug interactions in vitro were evaluated using cell viability assays, apoptosis induction, immunofluorescence, mitotic index, and immunoblotting. Breast cancer cells treated with auristatin analogue or 5T4-ADC were profiled by total- and phospho-proteomics. Antitumor efficacy of selected combinations was evaluated in 5T4-positive human breast or lung tumor xenografts in vivo.
In vitro, auristatin-based agents displayed strong synergistic or additive activity when combined with PF-384 or taxanes, respectively. Further, treatment of 5T4-ADC plus PF-384 resulted in stronger induction of apoptosis and cell line-specific attenuation of pAKT and pGSK. Interestingly, proteomic analysis revealed unique effects of auristatins on multiple components of mRNA translation. Addition of PF-384 further amplified effects of 5T4-ADC on translational components, providing a potential mechanism of synergy between these drugs. In human tumor xenografts, dual targeting with 5T4-ADC/PF-384 or 5T4-ADC/paclitaxel produced substantially greater antitumor effects with longer average survival as compared with monotherapy treatments.
Our results provide a biologic rationale for combining 5T4-ADC with either PI3K/mTOR pathway inhibitors or taxanes and suggest that mechanisms underlying the synergy may be attributed to cellular effects of the auristatin payload.
利用抗体药物偶联物（ADC）靶向治疗实体瘤或液体瘤可带来显著的临床获益。本研究旨在探讨基于auristatin 的 ADC 在癌症的临床前模型中的联合治疗方案。
将基于 auristatin 的抗 5T4 抗体偶联物（5T4-ADC）与 auristatin 有效载荷与双重 PI3K/mTOR 催化位点抑制剂 PF-05212384（PF-384）或紫杉烷类药物联合应用于一系列肿瘤细胞系中。通过细胞活力测定、凋亡诱导、免疫荧光、有丝分裂指数和免疫印迹评估体外药物相互作用。用全蛋白和磷酸化蛋白组学对用 auristatin 类似物或 5T4-ADC 处理的乳腺癌细胞进行分析。在体内 5T4 阳性人乳腺癌或肺癌肿瘤异种移植模型中评价选定组合的抗肿瘤疗效。
体外，auristatin 类药物与 PF-384 或紫杉烷类药物联合使用时显示出很强的协同或相加活性。此外，5T4-ADC 联合 PF-384 治疗可导致更强的凋亡诱导和细胞系特异性 pAKT 和 pGSK 的衰减。有趣的是，蛋白质组学分析显示 auristatins 对多个 mRNA 翻译成分有独特的作用。PF-384 的加入进一步放大了 5T4-ADC 对翻译成分的作用，为这些药物之间的协同作用提供了潜在的机制。在人肿瘤异种移植模型中，与单药治疗相比，5T4-ADC/PF-384 或 5T4-ADC/紫杉醇的双重靶向治疗产生了更大的抗肿瘤作用，平均生存时间更长。
我们的研究结果为 5T4-ADC 与 PI3K/mTOR 通路抑制剂或紫杉烷类药物联合应用提供了生物学依据，并表明协同作用的机制可能归因于 auristatin 有效载荷的细胞作用。
