癌症免疫療法是繼傳統手術、化療與放射線療法之後的新興療法，主要是利用提昇病人自身的免疫能力來對抗腫瘤，並降低副作用。我們的研究策略是希望藉由抑制負向調控免疫作用的分子來提升免疫反應以對抗腫瘤。為此，我們利用已建立的腫瘤小鼠模式與干擾性核醣核酸的技術來建立一個新平台，用以系統性地篩選出對腫瘤治療有療效的shRNA。首先我們將針對特定分子所購得的三株shRNA做等量混合後遞送到帶有腫瘤的小鼠腹部，並發現其中clec4a2 shRNA對小鼠腫瘤生長能形成最佳的抑制效果。由體外實驗發現，這些產生療效的腫瘤小鼠淋巴球，對腫瘤細胞有較高的細胞型毒殺活性。由於此療效是使用混合的clec4a2 shRNA所觀察到的，因此接下來我們便針對個別shRNA做研究：在利用西方墨點法確認了三株shRNA個別抑制效果後，我們分別將這三株clec4a2 shRNA遞送至小鼠體內，並觀察到其中clec4a2-1 shRNA和clec4a2-3 shRNA能抑制腫瘤的生長。由機制方面去探討，發現在clec4a2-1 shRNA和clec4a2-3 shRNA治療的小鼠淋巴球，對腫瘤細胞具有較高的細胞型毒殺活性。而由免疫組織化學染色的實驗得知，這些產生療效的小鼠在腫瘤部份具有較多的CD4+與CD8+ 淋巴球浸潤。最後在外送clec4a2基因的補償實驗中，我們更進一步證實此療效是由於遞送的clec4a2 shRNA抑制了小鼠體內clec4a2基因表現所導致。

Cancer immunotherapy, contrasted with traditional tumor therapy, is a new strategy to give rise to the immune response of patients oneself and destroy the tumor cells without the unwanted side-effects. One of the fast and efficient approaches of cancer immunotherapy is to inhibit the molecules which play a negative role in anti-tumor immunity. Utilizing an established animal model and the RNAi technique, we design a platform to find the potential therapeutic shRNA against negative regulator of dendritic cell by systematic screening. At first, we deliver mixed three shRNA into the abdomen of tumor-bearing mice and observe the tumor curve. The data show that mice treated with clec4a2 shRNA demonstrating the best therapeutic effect and inducing higher cytotoxic activity in lymphocyte. To analyse individual shRNA further, we check clec4a2 shRNA knockdown efficacy and then separately deliver three shRNA to tumor-bearing mice. Observing the tumor curve, mice which treated with clec4a2-1 shRNA and clec4a2-3 shRNA show the better therapeutic effect. To investigate the possible mechanism, the therapeutic effect is caused of enhanced cytotoxic activity in lymphocyte and more CD4+ and CD8+ lymphocyte infiltration in tumor part. Finally, we validate the therapeutic effect by compensating the shRNA-treated mice for clec4a2 gene.

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