結締組織生長因子於癌症代謝之影響

Abstract

目的 : 結締組織生長因子 (CTGF) 會抑制口腔鱗狀上皮細胞癌和非微小型細胞肺癌的轉移能力。我們假說結締組織生長因子可能藉由干擾癌症代謝而進一步調控癌症進程的發生。 實驗設計 : 利用海馬24生物能量分析儀來測量正常上皮細胞，口腔鱗狀細胞癌和非小型細胞肺癌的代謝。藉由博登細胞移行器實驗來分析癌細胞移行和侵入之實驗。 結果 : 本研究中發現結締組織生長因子降低糖解作用及氧化磷酸化 (P <0.05, P <0.01)，更進一步減少細胞內三磷酸腺苷產物和乳酸堆積 (P <0.05, P <0.01)，但在正常的上皮細胞中並沒有觀察到此現象。另外，也發現結締組織生長因子也會抑制氧化磷酸化的代償 (P <0.05)，且減少粒線體活性。我們研究結果證明結締組織生長因子減少粒線體去氧核醣核酸拷貝數，而造成降低癌細胞移行和侵入之能力 (P <0.05, P <0.01)。同時，也發現粒線體轉錄因子A (mtTFA; TFAM) 蛋白表現與結締組織生長因子呈現負相關。在口腔鱗狀上皮細胞癌病人中也觀察到表現越多的粒線體轉錄因子A，病人的存活率就降低。有趣的是，藉由基因抑制內生性的粒線體轉錄因子A，會導致降低口腔鱗狀細胞癌和非小型細胞肺癌的癌細胞移行和侵入之能力。且如果再度表現粒線體轉錄因子A可以回復結締組織生長因子所抑制的癌症進程 (P <0.05, P <0.01)。 結論 : 結締組織生長因子在癌症代謝中扮演一個重要的調控者，是經由抑制粒線體轉錄因子A的表現，而降低了糖解作用以及氧化磷酸化，更進一步的導致口腔鱗狀上皮細胞癌和非微小型細胞肺癌的癌症進程之下降。

Purpose: Connective tissue growth factor (CTGF) has been shown to inhibit the metastatic activity of oral squamous cell carcinoma (OSCC) and non-small-cell lung carcinoma (NSCLC). We hypotheses that CTGF could interfere cancer metabolism and regulate tumor progression. Method: Metabolism pathways, including glycolysis and oxygen phosphorylation were measured by XF24 bioenergetic assay in normal epithelial, OSCC and NSCLC cells. Migration and invasion abilities of cells were performed by modified Boyden chamber assay. Result: We observed that CTGF reduced cellular ATP production and lactate levels (P <0.01, P <0.05), which may be caused by decreased glycolysis and oxygen phosphorylation in OSCC and NSCLC (P <0.05, P <0.01), but no significant effect on normal epithelial cells. This small secreted protein also inhibited oxidative phosphorylation compensation (P <0.05), and reduced mitochondrial activity. Our data demonstrated that CTGF decreased mitochondrial DNA copy numbers, which resulted in the repression of cancer cell migration and invasion abilities (P <0.01). We observed that mitochondrial transcription factor A (mtTFA; TFAM) protein expression negatively correlated with CTGF. mtTFA expression was positively associated with poor survival in OSCC patients (P <0.01). Interestingly, transiently knockdown endogenous mtTFA decreased OSCC and NSCLC migration and invasion abilities (P <0.01). mtTFA overexpression restored CTGF-inhibited OSCC and NSCLC progression in vitro and in vivo (P <0.05, P <0.01). Conclusion: CTGF, a key regulator of cancer metabolism, decreased cancer metabolism, including glycolysis and oxygen phosphorylation via inhibiting mtTFA expression, and resulted in a reduction in cancer progression in OSCC and NSCLC cells.