Study of gene therapy for lymph node metastasis of oral squamous cell carcinoma

约30%的口腔癌患者有颈淋巴转移。浅表淋巴结多发性转移和淋巴结病变再生长的治疗难度较大。单纯疱疹病毒1型(HSV-1)的溶瘤病毒治疗是治疗此类淋巴结病变的一种很有前途的方法，因为HSV-1株HF10被报道对乳腺癌的淋巴转移有效。将转移淋巴结来源的口腔鳞状细胞癌(SCC)细胞接种于裸鼠颊部皮下，建立颈淋巴转移和肺转移的动物模型。作为口腔鳞状细胞癌的溶瘤病毒治疗药物，γ_134.5缺失突变株R849和HF10的原始株HF在口腔鳞状细胞癌细胞中进行了抗肿瘤活性的实验。R849和HF均可复制，细胞存活率呈时间依赖性下降。R849感染的细胞呈圆形，而HF可诱导多核巨细胞。然而，R849的病毒产量高于HF。当R849感染R849并与白血病分化剂六亚甲基双乙酰胺(HMBA)共同培养时，病毒产量显著增加。采用裸鼠口腔鳞状细胞癌模型，将R849单独或与HMBA联合应用于裸鼠体内，观察R849的抗肿瘤作用。R849对肿瘤生长有抑制作用，HMBA则进一步增强其作用。对HSV-1感染的炎症反应在感染部位产生氧自由基。我们证明了过氧化氢促进了感染细胞中HSV-1的释放。

Approximate 30 % of oral cancer patients have cervical lymph node metastasis. It is very hard to treat multiple metasatsis of superficial lymph nodes and regrowth of lymph node lesions. Oncolytic virotherapy with a replication-competent herpes simplex virus type 1 (HSV-1) is a promising approach for the treatment of such lymph node lesions, because HSV-1 strain HF10 was reported to be effective for lymph node metastasis of mammary cancer. We inoculated oral squamous cell carcinoma (SCC) cells derived from a metastatic lymph node subcutaneously into buccal area of nude mice and made a model system of cervical lymph node metastasis and lung metastasis. As agents for oncolytic virotherapy for oral SCC, γ_134.5-deficent mutant R849 and HF, the original strain of HF10, were tested for anti-tumor activity in oral SCC cells. Both R849 and HF could replicate and cell viability was decreased in a time-dependent manner. Cell rounding was observed in R849-infected cells, whereas HF induced multinuclear giant cells. However, the virus yield of R849 was higher than that of HF. When R849 was infected with R849 and cultured in the presence of hexamethylene bisacatamide (HMBA), a differentiating agent of leukemia, the virus production was increased markedly. The anti-tumor effect of R849 was also examined with the use of nude mouse model of oral SCC by injecting R849 into the tumors alone or in combination with intraperitoneal injection of HMBA. The tumor growth was suppressed by R849 treatment and the effect was further enhanced with HMBA. Inflammation response to HSV-1 infection produces oxygen radicals at the infection site. We demonstrated that hydrogen peroxide enhanced the release of HSV-1 from infected cells.