Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California, United States of America.
PLoS One. 2012;7(2):e31070. doi: 10.1371/journal.pone.0031070. Epub 2012 Feb 15.
Treatment options for triple negative breast cancer (TNBC) are generally limited to cytotoxic chemotherapy. Recently, anti-epidermal growth factor receptor (EGFR) therapy has been introduced for TNBC patients. We engineered a novel nanobioconjugate based on a poly(β-L-malic acid) (PMLA) nanoplatform for TNBC treatment. The nanobioconjugate carries anti-tumor nucleosome-specific monoclonal antibody (mAb) 2C5 to target breast cancer cells, anti-mouse transferrin receptor (TfR) antibody for drug delivery through the host endothelial system, and Morpholino antisense oligonucleotide (AON) to inhibit EGFR synthesis. The nanobioconjugates variants were: (1) P (BioPolymer) with AON, 2C5 and anti-TfR for tumor endothelial and cancer cell targeting, and EGFR suppression (P/AON/2C5/TfR), and (2) P with AON and 2C5 (P/AON/2C5). Controls included (3) P with 2C5 but without AON (P/2C5), (4) PBS, and (5) P with PEG and leucine ester (LOEt) for endosomal escape (P/mPEG/LOEt). Drugs were injected intravenously to MDA-MB-468 TNBC bearing mice. Tissue accumulation of injected nanobioconjugates labeled with Alexa Fluor 680 was examined by Xenogen IVIS 200 (live imaging) and confocal microscopy of tissue sections. Levels of EGFR, phosphorylated and total Akt in tumor samples were detected by western blotting. In vitro western blot showed that the leading nanobioconjugate P/AON/2C5/TfR inhibited EGFR synthesis significantly better than naked AON. In vivo imaging revealed that 2C5 increased drug-tumor accumulation. Significant tumor growth inhibition was observed in mice treated with the lead nanobioconjugate (1) [P = 0.03 vs. controls; P<0.05 vs. nanobioconjugate variant (2)]. Lead nanobioconjugate (1) also showed stronger inhibition of EGFR expression and Akt phosphorylation than other treatments. Treatment of TNBC with the new nanobioconjugate results in tumor growth arrest by inhibiting EGFR and its downstream signaling intermediate, phosphorylated Akt. The nanobioconjugate represents a new generation of nanodrugs for treatment of TNBC.
三阴性乳腺癌 (TNBC) 的治疗选择通常限于细胞毒性化疗。最近，抗表皮生长因子受体 (EGFR) 疗法已被引入用于 TNBC 患者。我们设计了一种基于聚（β-L-苹果酸）（PMLA）纳米平台的新型纳米生物缀合物，用于 TNBC 治疗。该纳米生物缀合物携带抗肿瘤核小体特异性单克隆抗体 (mAb) 2C5 以靶向乳腺癌细胞、抗小鼠转铁蛋白受体 (TfR) 抗体以通过宿主内皮系统递药，以及用于抑制 EGFR 合成的 Moropho 反义寡核苷酸 (AON)。纳米生物缀合物变体为：(1) 载有 AON、2C5 和抗 TfR 的 P（BioPolymer），用于肿瘤内皮和癌细胞靶向以及 EGFR 抑制（P/AON/2C5/TfR），以及 (2) 载有 AON 和 2C5 的 P (P/AON/2C5)。对照物包括 (3) 载有 2C5 但不含 AON 的 P (P/2C5)、(4) PBS 和 (5) 载有聚乙二醇和亮氨酸酯 (LOEt) 用于内涵体逃逸的 P (P/mPEG/LOEt)。药物通过静脉注射到携带 MDA-MB-468 TNBC 的小鼠体内。通过 Xenogen IVIS 200（活体成像）和组织切片的共聚焦显微镜检查用 Alexa Fluor 680 标记的注射纳米生物缀合物的组织积累。通过 Western blot 检测肿瘤样本中的 EGFR、磷酸化和总 Akt 水平。体外 Western blot 显示，主要的纳米生物缀合物 P/AON/2C5/TfR 可显著抑制 EGFR 合成，优于裸 AON。体内成像显示 2C5 增加了药物在肿瘤中的积累。用先导纳米生物缀合物 (1) [P = 0.03 与对照组相比；P<0.05 与纳米生物缀合物变体 (2) 相比] 观察到显著的肿瘤生长抑制。先导纳米生物缀合物 (1) 还显示出比其他治疗方法更强的 EGFR 表达和 Akt 磷酸化抑制作用。用新型纳米生物缀合物治疗 TNBC 通过抑制 EGFR 和其下游信号转导中间物磷酸化 Akt 导致肿瘤生长停滞。该纳米生物缀合物代表了治疗 TNBC 的新一代纳米药物。
