Swick Adam D, Stein Andrew P, McCulloch Timothy M, Hartig Gregory K, Ong Irene M, Sampene Emmanuel, Prabakaran Prashanth J, Liu Cheng Z, Kimple Randall J
Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA.
Department of Otolaryngology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; University of Wisconsin Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA.
Oral Oncol. 2017 Jan;64:65-72. doi: 10.1016/j.oraloncology.2016.11.017. Epub 2016 Dec 8.
Patient derived xenografts (PDXs) represent an essential tool in oncologic research, and we sought to further expand our repertoire of head and neck squamous cell carcinoma (HNSCC) while determining potential boundaries for this system.
We consented new patients for PDX development and determined if a 24-h time delay from tumor excision to xenograft implantation affected PDX establishment. We developed a tissue microarray (TMA) from formalin fixed, paraffin embedded PDXs and their subsequent passages and carried out quantitative immunohistochemistry for EGFR, pEGFR, pAkt, pERK and ERCC1. First and last passaged PDXs were compared via a paired t-test to examine for the stability of protein expression across passages. We performed a similar comparison of the mutational profile of the patient tumor and resulting xenografts using a targeted sequencing approach.
No patient/tumor characteristics influenced PDX take rate and the 24-h time delay from tumor excision to xenograft implantation did not affect PDX establishment, growth or histology. There was no significant difference in biomarker expression between the first and last passaged PDXs for EGFR, pEGFR, pAkt, and ERCC1. For pERK there was a significant difference (p=0.002), but further analysis demonstrated this only arose in three of 15 PDXs. Targeted sequencing revealed striking stability of passenger and likely driver mutations from patient to xenograft.
The stability of protein expression across PDX passages will hopefully allow greater investigation of predictive biomarkers in order to identify ones for further pre-clinical and clinical investigation.
患者来源的异种移植瘤（PDXs）是肿瘤学研究中的重要工具，我们试图进一步扩充头颈部鳞状细胞癌（HNSCC）的模型库，并确定该系统的潜在局限性。
我们征得新患者同意开展PDXs研究，确定肿瘤切除至异种移植植入24小时的时间延迟是否会影响PDXs的建立。我们从福尔马林固定、石蜡包埋的PDXs及其后续传代样本中制作了组织微阵列（TMA），并对表皮生长因子受体（EGFR）、磷酸化表皮生长因子受体（pEGFR）、磷酸化蛋白激酶B（pAkt）、磷酸化细胞外信号调节激酶（pERK）和切除修复交叉互补蛋白1（ERCC1）进行了定量免疫组化分析。通过配对t检验比较首次传代和末次传代的PDXs，以检测各代间蛋白质表达的稳定性。我们采用靶向测序方法对患者肿瘤和所得异种移植瘤的突变谱进行了类似比较。
患者/肿瘤特征均不影响PDXs的植入率，肿瘤切除至异种移植植入24小时的时间延迟不影响PDXs的建立、生长或组织学。首次传代和末次传代的PDXs在EGFR、pEGFR、pAkt和ERCC1的生物标志物表达上无显著差异。pERK存在显著差异（p=0.002），但进一步分析表明，仅15个PDXs中的3个出现此情况。靶向测序显示，从患者到异种移植瘤，过客突变和可能驱动突变具有显著稳定性。
PDXs各代间蛋白质表达的稳定性有望促进对预测性生物标志物的深入研究，以便确定可用于进一步临床前和临床研究的生物标志物。
