An exploitation of gene targeting therapy against hypoxic condition of oral carcinoma.

癌细胞因其高增殖率而暴露于低氧状态：然而，癌细胞对低氧诱导的细胞死亡具有抵抗力。低氧诱导因子(HIF)被认为是维持细胞在低氧状态下动态平衡的转录因子。应用DNA微阵列技术检测HIF下游基因，发现编码血管扩张肽的腺髓质素基因产物。对22例北海道大学附属医院就诊的舌鳞癌患者进行免疫组织化学检测。22例受检者中有11例肾上腺髓质素阳性。对其进行临床病理检查。在12例颈淋巴转移病例中，8例肾上腺髓质素阳性。在10例无淋巴结转移的病例中，仅3例肾上腺髓质素表达阳性。我们构建了两个被认为具有拮抗作用的肾上腺髓质素突变型表达载体，AMA214为缺失突变质粒，缺失27-115个氨基酸，116个苏氨酸为丝氨酸，AMA224缺失95-115个氨基酸，116个氨基酸发生相同突变。AMA214和AMA224注射可诱导SCID小鼠移植瘤消退。CD31阳性的肿瘤内皮细胞消失。

Cancer cells are exposed to hypoxic state because of their high proliferation rate: however, cancer cells are resistant to hypoxia-induced cell death. Hypoxia Inducible Factor (HIF) was identified as the transcription factor which maintains the homeostasis of the cell in hypoxic state. We examined the downstream genes of HIF by DNA micro array and we found that adenomemedullin, a blood vessel expansive peptide encoding gene product.Twenty-two cases of tongue squamous cell carcinoma who consulted the Hokkaido University Hospital were examined by immunohistochmistry. Adrenomedullin was detected in 11 of 22 cases examined. They were investigated clinico-pathologically. mong the 12 cases of cervical lymph node metastasis cases, 8 cases were positive for aderenomedullin. In contrast, only 3 cases were positive for adrenomedullin in 10 cases without lymph node metastasis.We reconstruct two mutant expression plasmids of adrenomedullin that are thought to function as antagonist, AMA214 is deletion and mutant plasmid with 27-115 amino acid deletion and 116 threonine into serine..AMA224 has deletion of 95-115 amino acid and the same mutation in 116 amino acid. AMA214 and AMA224 injection induced the regression of transplanted tumors in SCID mouse. CD31-positive tumor endothelial cells were disappeared in these animals.