介白素-10 (interleukin-10) 主要由免疫細胞分泌並影響宿主清除病毒與持續感染的過程。在病毒相關的腫瘤中，已證明介白素-10可扮演腫瘤抑制與致癌的角色，顯示介白素-10在病毒引發的腫瘤進展中仍有爭議。我們過去研究結果顯示，有高人類乳突病毒 (human papillomavirus) 拷貝數 (copy number) 的肺癌腫瘤組織相較於低人類乳突病毒拷貝數的組織有較高的介白素-10表現。此外，介白素-10 non-ATA 單倍型 (haplotype) 的病患有較高的介白素-10表現，其預後也較有低介白素-10表現的介白素-10 ATA 單倍型的病患差，特別在人類乳突病毒感染的肺癌病患中更為明顯。因此，我們預期介白素-10在人類乳突病毒相關的肺癌腫瘤化過程中，可能扮演重要角色。本研究分析一系列肺癌細胞株介白素-10的表現量，結果顯示在人類乳突病毒感染的肺癌細胞 (TL1與TL2) 中介白素-10的表現量高於未被人類乳突病毒感染的肺癌細胞。我們使用訊號傳遞路徑抑制劑測試E6調控介白素-10轉錄的訊號傳遞路徑，結果顯示E6調控介白素-10轉錄主要是經由PI3K/AKT路徑造成磷酸化CREB所調控。而E6調控的介白素-10能促進腫瘤的軟瓊脂生長與侵襲能力。為了瞭解此現象的作用機制，經由PCR array分析，顯示CIP2A受E6調控的介白素-10正向調控，且負責介白素-10所造成的腫瘤侵襲與軟瓊脂生長能力。由於介白素-10可以促進腫瘤細胞中抗細胞凋亡蛋白的表現並造成腫瘤免疫逃避，因此，我們接著探討FasL所調控的細胞凋亡是否能促進肺腫瘤的進程與肺癌病患較差的預後。FasL高表現的FasL -844CC基因型已被證實與癌症風險有關。因此，我們測定385位肺癌病患的FasL -844T/C基因型。帶有FasL -844CC基因型的肺癌病患在晚期癌症比早期癌症多。FasL -844CC基因型的肺癌病患比FasL -844TT+TC基因型的肺癌病患亦較容易有腫瘤復發的情況。Cox多變相迴歸分析結果顯示FasL -844CC基因型的肺癌病患比FasL -844TT+TC基因型的病患有較差的總存活與無復發存活預後。總而言之，在本研究中，我們發現介白素-10與FasL藉由免疫逃避與介白素-10/介白素-10受體的自泌環 (autocrine loop) 造成人類乳突病毒相關肺癌的惡性度。因此，介白素-10與FasL可能為促進人類乳突病毒相關的肺腺癌病患預後之免疫治療的分子標的。
IL-10 is predominately secreted from immune cells and determines the process of virus clearance and persistent infection of host. IL-10 has been shown to play tumor suppressive and oncogenic role in viral-associated human cancers, revealing the fact that the role of IL-10 in virus-induced tumor progression is still controversial. Our previous study showed that lung tumors with high HPV copy number had higher IL-10-expression than those with low HPV copy number. In addition, IL-10 non-ATA haplotype patients with high IL-10 mRNA expression had poorer prognosis than IL-10 ATA haplotype patients with low IL-10 mRNA expression, especially in HPV16/18-infected lung cancer patients. Therefore, we expected that IL-10 might play an important role in HPV-associated lung tumorigenesis. In this study, a panel of lung cancer cells was collected to evaluate the IL-10 expression. Our data showed that HPV-infected lung cancer cells (TL1 and TL2) had higher IL-10 expression than in HPV-uninfected lung cancer cells. Different signaling pathway inhibitors were used to test which signaling pathways could be involved in E6-induced IL-10 transcription in lung cancer cells. The result showed that E6-induced IL-10 transcription was mainly through the phosphorylation of CREB by PI3K/AKT pathway. Interestingly, IL-10 induced by E6 significantly promoted soft-agar growth and matrigel invasion capability. To verify the underlying mechanism, PCR array showed that CIP2A upregulated by E6-mediated IL-10 may be responsible for IL-10-induced cell invasiveness and soft-agar growth. IL-10 can elevate antiapoptotic protein expression in tumor cells and contribute to cancer immune escape. Therefore, we next questioned whether FasL-mediated apoptosis could promote HPV-associated lung tumor progression and consequently result in patients with poorer prognosis. FasL -844CC genotype with high FasL expression has been shown to associate with tumor risks. We therefore collected 385 patients to determine FasL -844T/C polymorphism by PCR-RFLP. Patients with the FasL -844CC genotype had high prevalence with advanced tumors than with early tumors. Interestingly, patients with the FasL -844CC genotype were more prone to tumor relapse when compared with those with the FasL -844TT+TC genotype. Multivariate Cox regression analysis showed that patients with the FasL -844CC genotype had poorer overall survival and relapse-free survival than those with the FasL -844TT+TC genotype. Taken together, in this study, we demonstrated that IL-10 and FasL could contribute to HPV-associated lung tumor malignancy via immune escape and autocrine loop of IL-10/IL-10R. Therefore, IL-10 and FasL may be used as molecular targets for immunotherapeutic interventions for improving the clinical outcome of lung adenocarcinoma patients who had HPV16/18 E6-positive tumors.
