Ivosidenib藥物機制探討與聯合治療藥物篩選應用於IDH1突變型肝內膽管癌治療

Abstract

肝內膽管癌（intrahepatic cholangiocarcinoma, iCCA）是第二常見的原發性肝癌類型，由於腫瘤位置在肝臟內部，手術切除腫瘤的難度較大。目前一線治療是胞毒性化學療法，但其臨床療效有限，且iCCA具有高度基因異質性，這促使標靶治療成為發展的方向。異檸檬酸脫氫酶I型（Isocitrate dehydrogenase 1, IDH1）是iCCA中常見的突變，突變後會導致致癌代謝物的積累，引發表觀遺傳學重新編程、代謝壓力和氧化壓力上升等作用，最終導致細胞癌化。Ivosidenib是一種通過美國FDA核准的IDH1抑制劑，能有效抑制突變IDH1，減少致癌代謝物的濃度，延長無症狀存活期。然而，在長期應用中，ivosidenib未能有效減小腫瘤體積，且易導致藥物抗性，其臨床效果有限。因此，本研究旨在通過與候選藥物聯合治療，結合ivosidenib的病程控制效果和候選藥物的腫瘤清除能力，以期達到更好的治療效果。研究首先評估了ivosidenib的療效，發現其雖然能有效抑制突變IDH1，但在MTT試驗中顯示出有限的細胞毒殺能力，需通過長期藥物處理後的群落生成試驗才能觀察到對RBE肝內膽管癌細胞的長期生存抑制效果。同時，本研究發現，ivosidenib治療後會提升細胞遷移能力並增加CXCL1趨化因子的表達，顯示其對促進癌症進展具有潛在作用。此外，本研究試圖探索高濃度ivosidenib產生毒殺效果的機制，發現高濃度ivosidenib處理下能會使細胞週期停滯並誘發DNA損傷，是抑制RBE細胞活性的潛在可能成因。 最後，本研究篩選了DNA/RNA合成抑制劑、表觀遺傳學藥物、酪胺酸激酶抑制劑、代謝調節劑等四大類候選藥物，許多藥物都在MTT試驗中展現對RBE細胞顯著的毒殺能力，不過在與ivosidenib聯合給藥的增敏性分析中都僅展現出加乘效應。不過，本研究認為這些聯合給藥能夠時抑制致癌代謝物生成並同時毒殺癌細胞，有望在長期給藥下或活體環境內存在治療潛力。

Intrahepatic cholangiocarcinoma (iCCA) ranks as the second most prevalent type of liver cancer, posing significant challenges in treatment due to high recurrence rates and the complexity of resection surgery. While chemotherapy is commonly used as a primary treatment, its effectiveness is limited by the genetic diversity of the cancer and the development of drug resistance mechanisms. Mutant isocitrate dehydrogenase 1 (mIDH1) represents a promising target for iCCA therapy, as it contributes to epigenetic reprogramming, metabolic stress, and other factors pivotal in disease progression. Ivosidenib (IVO), an FDA-approved drug, inhibits the mIDH1 enzyme, thereby reducing oncometabolite levels and inhibiting tumor growth. However, clinical studies have indicated low response rates and the emergence of drug resistance with prolonged use. In our study, we first evaluated the efficacy of ivosidenib, confirming its ability to effectively inhibit mutant IDH1. Nevertheless, it demonstrated limited cytotoxicity in MTT assays, necessitating a 14-day colony formation assay to observe its long-term survival inhibitory effects on RBE iCCA cells. Notably, ivosidenib treatment was associated with increased migration ability and upregulation of the chemokine CXCL1 in RBE cells, suggesting a partial induction of cancer progression. Furthermore, we investigated the mechanisms underlying the cytotoxic effects of high concentrations of ivosidenib but did not observe corresponding results in apoptosis, cell cycle, or DNA damage assays. Finally, we screened four categories of candidate drugs—DNA/RNA synthesis inhibitors, epigenetic agents, tyrosine kinase inhibitors, and metabolic inhibitors. Many of these drugs demonstrated significant cytotoxicity against RBE cells in MTT assays but only additive effects when combined with ivosidenib in sensitization assays. Given these findings, our study highlights the potential of these combination therapies to inhibit oncometabolite synthesis by ivosidenib and induce cytotoxicity in iCCA cells through candidate drugs. We anticipate that these combinations hold promise for long-term treatment and in vivo settings.