反义表皮生长因子受体纳米颗粒对小鼠头颈鳞状细胞癌放疗增敏的实验

目的应用反义表皮生长因子受体（epidermal growth factor receptor，EGFR）纳米颗粒，研究阻断EGFR表达，对小鼠头颈部鳞状细胞癌（简称头颈鳞癌）敏感性的作用。方法载反义EGFR寡核苷酸纳米颗粒转染SCC VII细胞株，通过Western—blot研究其蛋白抑制效应。放射治疗千预后，细胞克隆试验和MTT试验检测细胞的放射敏感性，流式细胞仪检测细胞周期分布和凋亡情况：构建小鼠头颈癌荷瘤模型，瘤体注射反义EGFR纳米颗粒，予以4Gy放射治疗，观察肿瘤生长抑制情况。结果反义EGFR纳米颗粒明显抑制EGFR蛋白的表达情况：反义EGFR纳米颗粒与放疗联合降低了肿瘤细胞克隆形成能力及生长能力（P〈0．05）：肿瘤细胞发生G1期阻滞，细胞凋亡率增加（P〈0．05）。体内实验发现反义EGFR纳米颗粒组肿瘤生长明显延缓。结论反义EGFR纳米颗粒通过下调EGFR的表达，使SCC VII细胞发生G1期阻滞，具有放疗增敏效应。

Antisense epidermal nanoparticles enhanced cells in vitro and in vivo growth factor receptor radiosensitivity in SCC VII

OBJECTIVE To evaluate the effects of antisense epidermal growth factor receptor （EGFR） nanoparticles on the radiosensitivity of head and neck squamous cell carcinoma in mice. METHODS The inhibition of EGFR was assessed by western-blot analysis. Nanoparticles encapsulated antisense EGFR oligonucleotides were transfected into SCC VII. After radiotherapy, the relative radiosensitivity of the cells was assessed in vitro by MTT and standard clonogenic assay. The proportion of apoptotic cells and cell cycle stages were analyzed by flow cytometry. C3H/He mice with SCC VII tumor heterografts were treated with antisense-EGFR-nanoparticles or radiation therapy alone. The relative radiosensitivity of the tumors was assessed in vivo by growth delay assays. RESULTS The antisense EGFR nanoparticles could inhibit the expression of EGFR. When antisense EGFR nanoparticles and radiation therapy were combined together, clonogenic assay and MTT analysis showed that the decrease of proliferation in SCC VII cells. Flow cytometry analysis revealed cell cycle arrest in G1 phase and increased proportion of apoptotic cells. SCC VII tumor heterografts grew slowly in vivo. CONCLUSION Our results showed antisense EGFR nanoparticles enhanced radiosensitivity by inhibition of EGFR-mediated mechanisms of radioresistance.