Gene therapy for oral squamous cell carcinoma targeting tumor specific promoter activation

口腔鳞状细胞癌是口腔颌面部最常见的恶性肿瘤，其特点是由于肿瘤发生较浅，所以在宏观上能够被识别。这一特点有助于基因靶向治疗。首先，我们检测了E1AF在正常组织和肿瘤组织中的表达。E1AF是一个癌基因家族转录因子，我们注意到E1AF可以上调几种基质金属蛋白酶（matrix metalloproteinase， MMP）基因的启动子活性，并表明口腔鳞状细胞癌衍生细胞系的侵袭电位与E1AF和MMP的表达相关。我们分析了E1AF在非小细胞肺癌（NSCLC）细胞系和切除肿瘤中的表达。17个非小细胞肺癌细胞系中有15个表达E1AF mRNA， 19个肿瘤中有12个表达E1AF mRNA，而正常肺组织和肿瘤内伴随的正常细胞不表达E1AF mRNA。在口腔癌和正常组织中也得到了类似的结果。采用RT-PCR检测E1AF的表达。27例患者中15例检出E1AF，正常组织中未检出。Bnip3是一种促凋亡分子，包含BH3和跨膜？域。BH3蛋白现在被认为是凋亡信号的启动器。我们的研究结果表明，BnipS通过TM结构域将caspase募集到线粒体膜上，从而诱导细胞凋亡。构建了表达E1AF启动子驱动的腺病毒载体（Ad-F-Bik）的BH3分子Bik。将一株鳞状细胞癌细胞株SiHa移植到裸鼠体内。Ad-F-Bik每周两次应用于体内肿瘤。应用Ad-F-Bik抑制肿瘤生长，诱导肿瘤细胞凋亡。这些结果表明，利用腺病毒载体靶向肿瘤特异性表达分子进行基因治疗是有效的。

Oral squamous cell carcinoma is the mostcommon malignant tumor in oral and maxillofacial region, and has a property that oral carcinoma is able to be recognized macroscopy because of the superficial occurrence of tumors. This characteristics contribute to the gene targeting therapy.First, we examined E1AF expression in normal and tumor tissues. E1AF is anete-oncogene family transcription factor, and we have noted that E1AF can upregulate promoter activities of several matrix metalloproteinase (MMP) genes and showed that invasive potentials of oral squamous cell carcinoma-derived cell lines are correlated with expression of E1AF and MMPs. We analyzed the E1AF expression in cell lines and resected tumors of non-small-cell lung cancers (NSCLC). Fifteen out of 17 cell lines of NSCLC and 12 of 19 tumors expressed E1AF mRNA while normal lung tissue and concomitant normal cells within tumors did not express E1AF mRNA. Similar results were obtained in oral carcinoma and normal tissues. RT-PCR was utilizedto examine the expression of E1AF. Among the 27 patients, E1AF was detected in 15 cases and was not detected in normal tissues.Bnip3 is a pro-apoptotic molecule that contains BH3 and trans-membrane ? domains. BH3 only proteins are now thought to be the initiator of apoptotic signals. Our results suggest that BnipS induces apoptosis by recruiting caspases onto mitochondrial membrane through TM domain.Bik, a BH3 only molecule, expressing adenovirus vector driven by E1AF promoter was reconstructed (Ad-F-Bik). SiHa, a squamous cell carcinoma cell line was transplanted into nude mice. Ad-F-Bik was applied in vivo tumors twice a week. Tumor growth was inhibited by application of Ad-F-Bik, and apoptosis of tumor cells was induced.These results indicate that gene therapy targeting tumor specific expressing molecule is effective using adenovirus vector.