Radioimmunotherapy of PANC-1 Human Pancreatic Cancer Xenografts in NRG Mice with Panitumumab Modified with Metal-Chelating Polymers Complexed to 177Lu
Radioimmunotherapy of PANC-1 Human Pancreatic Cancer Xenografts in NRG Mice with Panitumumab Modified with Metal-Chelating Polymers Complexed to 177Lu
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DOI：
10.1021/acs.molpharmaceut.8b01040
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发表时间：
2019-02-01
影响因子：
4.9
通讯作者：
Reilly, Raymond M.
中科院分区：
文献类型：
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作者：
Aghevlian, Sadaf;Cai, Zhongli;Reilly, Raymond M.
我们的目的是评估放射免疫治疗（RIT）的有效性和正常组织毒性。NRG小鼠中的PANC-1人胰腺癌（PnCa）异种移植物，使用与金属螯合聚合物（MCP）连接的抗EGFR帕尼单抗，该金属螯合聚合物可提供13种DOTA螯合剂以络合β-发射体Lu-177。通过γ-H2 AX的共聚焦免疫荧光显微镜测量用帕尼单抗-MCP-Lu-177（0.3-1.2 MBq）体外处理的PANC-1细胞的克隆形成存活（CS）和这些细胞的核中的DNA双链断裂（DSB）。测量帕尼单抗-MCP-Lu-177放射性的亚细胞分布，并计算细胞核的吸收剂量。通过静脉注射6 MBq（10 μ g）帕尼单抗-MCP-Lu-177后监测体重、全血细胞计数（CBC）、血清丙氨酸氨基转移酶（ALT）和肌酐（Cr），评估非荷瘤NRG小鼠的正常组织毒性。RIT在NRG小鼠中用s.c.静脉注射6 MBq（10 μ g）帕尼单抗-MCP-Lu-177的PANC-1肿瘤。对照小鼠接受非特异性人IgG-MCP-Lu-177（6 MBq; 10 μ g）、未标记帕尼单抗（10 μ g）或生理盐水。比较肿瘤生长指数（TGI）。根据生物分布研究估计肿瘤和正常器官剂量。帕尼单抗-MCP-Lu-177在最高测试量（1.2 MBq）下使PANC-1细胞的体外CS降低7.7倍。未标记的帕尼单抗对PANC-1细胞的CS没有影响。帕尼单抗-MCP-Lu-177使γ-H2 AX病灶增加3.8倍。帕尼单抗-MCP-Lu-177在PANC-1细胞核中沉积3.84戈伊。与用生理盐水处理的NRG小鼠相比，给予NRG小鼠帕尼单抗-MCP-Lu-177（6 MBq; 10 μ g）未引起体重、CBC或ALT的变化，仅引起Cr的轻微增加。与正常盐水处理的小鼠（TGI = 5.8 +/- 0.5; P < 0.01）相比，帕尼单抗-MCP-Lu-177强烈抑制NRG小鼠（TGI = 2.3 +/- 0.2）中的肿瘤生长。未标记的帕尼单抗对肿瘤生长没有影响（TGI = 6.0 +/- 1.6; P > 0.05）。PANC-1肿瘤的吸收剂量为12.3戈伊。最高正常器官剂量由胰腺、肝脏、脾脏和肾脏吸收。我们得出结论，帕尼单抗-MCP-Lu-177的EGFR靶向RIT能够克服NRG小鼠中KRAS突变型PANC-1肿瘤对帕尼单抗的耐药性，并且可能是治疗人类PnCa的有希望的方法。
Our aim was to evaluate the effectiveness and normal tissue toxicity of radioimmunotherapy (RIT) of s.c. PANC-1 human pancreatic cancer (PnCa) xenografts in NRG mice using anti-EGFR panitumumab linked to metal-chelating polymers (MCPs) that present 13 DOTA chelators to complex the beta-emitter, Lu-177. The clonogenic survival (CS) of PANC-1 cells treated in vitro with panitumumab-MCP-Lu-177 (0.3-1.2 MBq) and DNA double-strand breaks (DSBs) in the nucleus of these cells were measured by confocal immunofluorescence microscopy for gamma-H2AX. Subcellular distribution of radioactivity for panitumumab-MCP-Lu-177 was measured, and absorbed doses to the cell nucleus were calculated. Normal tissue toxicity was assessed in non tumor-bearing NRG mice by monitoring body weight, complete blood cell counts (CBC), serum alanine aminotransferase (ALT), and creatinine (Cr) after i.v. injection of 6 MBq (10 mu g) of panitumumab-MCP-Lu-177. RIT was performed in NRG mice with s.c. PANC-1 tumors injected i.v. with 6 MBq (10 mu g) of panitumumab-MCP-Lu-177. Control mice received nonspecific human IgG-MCP-Lu-177 (6 MBq; 10 mu g), unlabeled panitumumab (10 mu g), or normal saline. The tumor growth index (TGI) was compared. Tumor and normal organ doses were estimated based on biodistribution studies. Panitumumab-MCP-Lu-177 reduced the CS of PANC-1 cells in vitro by 7.7-fold at the highest amount tested (1.2 MBq). Unlabeled panitumumab had no effect on the CS of PANC-1 cells. gamma-H2AX foci were increased by 3.8-fold by panitumumab-MCP-Lu-177. Panitumumab-MCP-Lu-177 deposited 3.84 Gy in the nucleus of PANC-1 cells. Administration of panitumumab-MCP-Lu-177 (6 MBq; 10 mu g) to NRG mice caused no change in body weight, CBC, or ALT and only a slight increase in Cr compared to NRG mice treated with normal saline. Panitumumab-MCP-Lu-177 strongly inhibited tumor growth in NRG mice (TGI = 2.3 +/- 0.2) compared to normal saline-treated mice (TGI = 5.8 +/- 0.5; P < 0.01). Unlabeled panitumumab had no effect on tumor growth (TGI = 6.0 +/- 1.6; P > 0.05). The absorbed dose of PANC-1 tumors was 12.3 Gy. The highest normal organ doses were absorbed by the pancreas, liver, spleen, and kidneys. We conclude that EGFR-targeted RIT with panitumumab-MCP-Lu-177 was able to overcome resistance to panitumumab in KRAS mutant PANC-1 tumors in NRG mice and may be a promising approach to treatment of PnCa in humans.