A study on the prevention of oral cancer metastasis by targeting a transcription factor NF-κB and protease

探讨NF-κB靶向治疗口腔癌的有效性。首先，在口腔癌活检标本中研究基质金属蛋白酶-9 （matrix metalloproteinase-9, MMP-9）在肿瘤侵袭转移中的作用。其次，为了阻断口腔癌细胞产生MMP-9的能力，我们尝试通过各种方法抑制转录因子NF-κB的激活。(1)应用明胶酶谱法检测57例口腔鳞癌活检标本中MMP-9的明胶溶酶活性。同样的标本也用抗mmp -9抗体免疫组织化学染色。各病例中MMP-9的溶胶活性与MMP-9的免疫组化染色程度相关。对57例口腔癌的明胶酶谱分析显示，活检标本中MMP-9的溶胶活性与口腔癌的组织病理侵袭性有统计学相关性，提示MMP-9的表达参与了口腔癌的侵袭和转移。(2)我们发现地塞米松（DEX）和白细胞介素-4 （IL-4）能抑制培养的口腔鳞状细胞癌细胞MMP-9的表达。DEX和IL-4通过抑制尿激酶型纤溶酶原激活物（uPA）的基因表达，抑制MMP-9前体向MMP-9活性形式的转化。可激活MMP-9和uPA基因表达的转录因子NF-κB的激活也被DEX和IL-4抑制。因此，DEX和IL-4可能靶向NF-κB抑制MMP-9的基因表达和活化。(3)正常人成纤维细胞传代早期可表达正常大小的NF-κB，而传代晚期成纤维细胞NF-κB的分子量降低至70-80 kD。正常细胞衰老可诱导细胞内NF-κ b降解蛋白酶的表达。而肿瘤细胞在100代后仍能稳定表达正常NF-κB分子。(4)形成了超抑制因子IκBα和显性负性IκBα激酶（IKK激酶）的表达载体。我们现在正在将表达载体转染到口腔癌细胞中，并检查这些载体对MMP-9表达的影响。结论：NF-κ b靶向治疗可能有助于预防口腔癌的侵袭和转移。少

We examined a validity of NF-κB targeting therapy of oral cancer. Firstly, the involvement of matrix metalloproteinase-9 (MMP-9) in cancer invasion and metastasis was studied in the biopsy specimens of oral cancer patients. Secondly, in order to block the capability of oral cancer cells to produce MMP-9, we attempted to inhibit the activation of a transcription factor NF-κB through various methods.(1) We examined a gelatinolytic activity of MMP-9 in the biopsy specimens of 57 cases of oral squamous cell carcinoma by gelatin zymography. The same specimens were also stained immunohistochemically by anti-MMP-9 antibody. The gelatinolytic activity of MMP-9 in each case correlated with the immunohistochemical staining degree of MMP-9. The gelatin zymographic analysis of 57 cases revealed that the gelatinolytic activity of MMP-9 in biopsy specimens statistically correlated with histopathological invasiveness of oral cancer, suggesting that MMP-9 expression contributes to the invasion and met … More astasis of oral cancer.(2) We found that the MMP-9 expression of cultured oral squamous cell carcinoma cell lines was inhibited by dexamethasone (DEX) and interleukin-4 (IL-4). DEX and IL-4 inhibited the conversion from MMP-9 precursor to active form of MMP-9 by inhibiting the gene expression of urokinase type plasminogen activator (uPA). The activation of a transcription factor NF-κB, which can activate gene expressions of MMP-9 and uPA, was also inhibited by DEX and IL-4. Therefore, DEX and IL-4 are likely to target NF-κB to inhibit the gene expression and activation of MMP-9.(3) Early-passage normal human fibroblasts can express normal size of NF-κB while the molecular size of NF-κB of late-passage fibroblasts was reduced to 70-80 kD.The senescence of normal cells may induce the intracellular NF-κB-degrading protease(s). In contrast, tumor cells can express normal NF-κB molecule stably evev after 100 passage.(4) The expression vectors of superreppressor IκBα and dominant negative IκBα kinases (IKK kinases) have been formed. We are now transtecting the expression vectors into oral cancer cells and examining the effects of these vectors on MMP-9 expression.In conclusion, NF-κB-targeting therapy may be useful to prevent invasion and metastasis of oral cancer. Less