IL-6 經由Smad恢復TGF-beta對樹狀細胞成熟的抑制

Abstract

在癌症病患，樹突狀細胞(DC)的功能明顯地受到抑制。而在犬傳染性花柳性的腫瘤(CTVT)模式中，當腫瘤進入自然的消退期，患犬之DC功能即恢復。已知CTVT會分泌高量的TGF-b.然而DC的功能缺失以及腫瘤進入消退期時之功能恢復，和TGF-b之間的關係以及機制上不明確。我們首先確認了CTVT分泌的TGF-b對單核球來原之C有抑制作用。給予TGF-b後，DC活化T淋巴的功能顯著的降低了，CD1a, CD40等分子的表現也減少了。以含有TGF-b之增長(P)期CTVT細胞上輕易培養DC, 也可以得到類似的效果。中和上清液中的TGF-b可以恢復DC活化T淋巴球的能力，也提高了DCMHCII的表現。實驗室之前的研究發現CTVT R期時，浸潤於腫瘤之間的淋巴球產生IL-6和TGF-b有很強的結抗效果。流是細胞儀的結果顯示IL-6可以有效的恢復DC被TGF-b抑制的MHCII表現。我們於是進一步測試IL-4是否會直接干擾TGF-b的傳導路徑。經由西方墨眼法以及共軛焦顯微鏡之觀察，我們發現IL-6會阻擋TGF-b引起之Smad2/3進入細胞核。在我們觀察IL-6減少核內Smad2/3的同時，並沒有偵測到抑制型Smad, Smad7表現而回饋控制TGF-b的傳導所致。本研究探討了宿主/癌症之間的交互關係，並提出力用IL-6回復癌症產生TGF-b 對 DC的傷害在癌症治療上的應用。

The dendritic cell (DC) activities are significantly hampered in many cancers. It is interesting that, in a canine cancer model, canine transmissible venereal tumor (CTVT), when the cancer enters a spontaneous regression (R), the inhibited DC activities are restored. CTVT produces high levels of TGF-b However, the role of TGF-b and 5h3 mechanisms involved in the DC functional suppresion and the restoration is largely unknown. We confirmed that the CTVT-derived TGF-b suppressed monocyte-derivedDC activities. After TGF-b treatment, the T cell activation through DC was impeded and the supernatants from the progression phase CTVT that contained TGF-b. Neutralizing the TGF-b in the supernatants by specific monoclonal antibody reversed the inhibition of DC-induces lymphocyte stimulation and also enhanced the DC MHC II expression. Our precious sstudy indicated that IL-6 produces by tumor infiltrating lymphocytes in the CTVT R phase sxhibited strong anti-TGF-b activity. The recovery of the TGF-b inhibitrf DC activities by IL-6 was thereforer studied. The flow cytometry results showed a strong reaction of IL6 in restoring TGF0b0down-regulated MHC expression on DCs. We ffurther verified whether IL-6 interfered with the TGF-b activities directly. Using Western blotting and confocal microscopy, we found that the nuclear translocation of Smad2/3, a sign of signal transduction of TGF-b, was blocked by adding IL-6. The evidence that the Smad7, which is an inhibitory Smad, was not oncreased in expression by adding IL-6 indicated that the nuclear translocation of Smad2/3 blocked by IL-6 was not through Smad7 pathway. This study provides in depth understanding of the host/cancer interactions and possible applications of IL-6 to restore DC activities in cancers that produce TGF-b.