| 摘要: | 根據世界衛生組織在2020年統計中，婦女乳癌新確診個案的11.7%已超過11.4%之男女肺癌新確診個案總和。此數據顯示對於乳癌更進一步的研究藉此提升療效日趨重要。其中，Trastuzumab是HER2+的乳癌患者在臨床治療上的重要標靶藥物之一，但是在臨床的使用上發現，大約有70%的HER2+的乳癌患者在使用Trastuzumab治療後未達到預期的效果，而透過先前的研究顯示，Trastuzumab的抗藥性t-DARPP相關。本實驗室多年來專注於天然產物抑制乳癌細胞生長的分子機制，在篩藥的過程中發現Quercetin可以有效抑制t-DARPP的表現。本篇利用透過聚合?連鎖反應、西方墨點法與免疫組織化學染色分析不同種類之細胞株與乳癌病患腫瘤證實HER2+的乳癌細胞株之t-DARPP之mRNA、蛋白的表現量皆高於其他種類乳癌細胞株，而乳癌患者組織其中19位HER2陽性乳癌患者之PPP1R1B表現量顯著高於40例HER2陰性患者(**p = 0.002)。接著，分別利用t-DARPP過表現或是受到抑制之BT-474穩定性乳癌細胞，並利用細胞計數、流式細胞儀與Transwell assay實驗，證實t-DARPP促進HER2+乳癌細胞進程。我們更進一步透過細胞計數實驗與西方墨點法證實t-DARPP可以促進AKT (Ser473)的磷酸化，以活化Trastuzumab阻斷之HER2介導之抗凋亡作用，藉此產生抗藥性。Quercetin可以抑制t-DARPP造成癌細胞的DNA損傷與細胞週期G2/M期的停滯，藉此誘發細胞凋亡。進一步利用細胞計數的方式證實Quercetin + Trastuzumab的共同治療下，其效果是顯著高於單一劑量。以此認為共同治療對於解決HER2+乳癌細胞之Trastuzumab抗藥性具可行性，但是未來仍然有Quercetin本身缺乏專一性以造成毒性等等問題需要解決。
According to the World Health Organization, 11.7% of newly diagnosed breast cancer cases in women have exceeded 11.4% of newly diagnosed lung cancer cases in men and women in 2020. This data suggested that further research into breast cancer to improve treatment is increasingly important. Among them, Trastuzumab is one of the important target drugs in the clinical treatment of HER2+ breast cancer patients, but in clinical use, it was found that about 70% of HER2+ breast cancer patients did not achieve the expected effect after treatment with Trastuzumab. Previous studies have shown that Trastuzumab's drug-resistant t-DARPP is related. For many years, our laboratory has focused on the molecular mechanism of natural compounds inhibiting the growth of breast cancer cells. During the drug screening process, we found that Quercetin can effectively inhibit the expression of t-DARPP. This study used PCR, Western blotting, and IHC to analyze different breast cancer cell lines and patients' tumors to confirm that the levels of t-DARPP mRNA and protein in HER2+ breast cancer cell lines are higher than those of other types of breast cancer cell lines. The expression level of PPP1R1B in 19 HER2+ breast cancer patients was significantly higher than that in 40 HER2- patients (**p = 0.002). Next, we used BT-474 stable HER2+ breast cancer cells overexpressed or inhibited by t-DARPP. We used cell counting, flow cytometry, and Transwell assay to confirm that t-DARPP promotes tumor progression of HER2+ breast cancer cells. We further confirmed by cell counting experiments and western blotting that t-DARPP can promote the phosphorylation of AKT (Ser473) to activate the HER2-mediated anti-apoptotic effect blocked by Trastuzumab, thereby producing drug resistance. In addition, Quercetin can inhibit the DNA damage caused by t-DARPP and arrest the G2/M phase of the cell cycle in cancer cells, thereby inducing apoptosis. Further cell counting was used to confirm that under the co-treatment of Quercetin + Trastuzumab, the effect was significantly higher than that of monotherapy. Based on this, it is considered that the co-treatment is feasible to solve the Trastuzumab resistance of HER2+ breast cancer cells. However, there are still problems in the future, such as the need for more specificity of Quercetin itself, which will cause toxicity. |
