Irtenkauf Susan M, Sobiechowski Susan, Hasselbach Laura A, Nelson Kevin K, Transou Andrea D, Carlton Enoch T, Mikkelsen Tom, deCarvalho Ana C
Hermelin Brain Tumor Center, Department of Neurosurgery, Henry Ford Hospital, Detroit, Michigan, USA.
Comp Med. 2017 Aug 1;67(4):300-314.
Glioblastoma is an aggressive primary brain tumor predominantly localized to the cerebral cortex. We developed a panel of patient-derived mouse orthotopic xenografts (PDOX) for preclinical drug studies by implanting cancer stem cells (CSC) cultured from fresh surgical specimens intracranially into 8-wk-old female athymic nude mice. Here we optimize the glioblastoma PDOX model by assessing the effect of implantation location on tumor growth, survival, and histologic characteristics. To trace the distribution of intracranial injections, toluidine blue dye was injected at 4 locations with defined mediolateral, anterioposterior, and dorsoventral coordinates within the cerebral cortex. Glioblastoma CSC from 4 patients and a glioblastoma nonstem-cell line were then implanted by using the same coordinates for evaluation of tumor location, growth rate, and morphologic and histologic features. Dye injections into one of the defined locations resulted in dye dissemination throughout the ventricles, whereas tumor cell implantation at the same location resulted in a much higher percentage of small multifocal ventricular tumors than did the other 3 locations tested. Ventricular tumors were associated with a lower tumor growth rate, as measured by in vivo bioluminescence imaging, and decreased survival in 4 of 5 cell lines. In addition, tissue oxygenation, vasculature, and the expression of astrocytic markers were altered in ventricular tumors compared with nonventricular tumors. Based on this information, we identified an optimal implantation location that avoided the ventricles and favored cortical tumor growth. To assess the effects of stress from oral drug administration, mice that underwent daily gavage were compared with stress-positive and -negative control groups. Oral gavage procedures did not significantly affect the survival of the implanted mice or physiologic measurements of stress. Our findings document the importance of optimization of the implantation site for preclinical mouse models of glioblastoma.
胶质母细胞瘤是一种侵袭性原发性脑肿瘤，主要局限于大脑皮层。我们通过将从新鲜手术标本中培养的癌干细胞（CSC）颅内植入8周龄雌性无胸腺裸鼠，开发了一组用于临床前药物研究的患者来源小鼠原位异种移植模型（PDOX）。在此，我们通过评估植入位置对肿瘤生长、存活及组织学特征的影响，优化胶质母细胞瘤PDOX模型。为追踪颅内注射的分布情况，在大脑皮层内具有确定的内外侧、前后及背腹坐标的4个位置注射甲苯胺蓝染料。然后使用相同坐标植入来自4名患者的胶质母细胞瘤CSC及一种胶质母细胞瘤非干细胞系，以评估肿瘤位置、生长速率以及形态学和组织学特征。向其中一个确定位置注射染料导致染料在整个脑室扩散，而在同一位置植入肿瘤细胞导致多灶性小脑室肿瘤的比例远高于其他3个测试位置。通过体内生物发光成像测量，脑室肿瘤的肿瘤生长速率较低，且5个细胞系中有4个的存活率降低。此外，与非脑室肿瘤相比，脑室肿瘤的组织氧合、脉管系统及星形细胞标志物的表达发生了改变。基于此信息，我们确定了一个避免脑室且有利于皮层肿瘤生长的最佳植入位置。为评估口服给药应激的影响，将每日接受灌胃的小鼠与应激阳性和阴性对照组进行比较。口服灌胃程序对植入小鼠的存活或应激的生理测量无显著影响。我们的研究结果证明了优化胶质母细胞瘤临床前小鼠模型植入部位的重要性。
