褪黑激素可引發膀胱泌尿上皮癌細胞生長停滯及抑制癌細胞侵襲能力之研究

膀胱泌尿上皮癌約佔診斷膀胱癌的九成，主要治療方式為經尿道內視鏡膀胱腫瘤切除手術，接續膀胱內灌注化療藥物或卡介苗。由於復發率和進展率及死亡率高，目前仍需要發展新的輔助治療來改善該病的預後。本研究的主要目的是探討褪黑激素對人類的膀胱癌細胞株，包括T24和UMUC3的抗癌作用，並評估在膀胱癌術後的輔助治療上的角色。我們用流式細胞儀（flow cytometry）及Hoechst 33342核染色試驗（Hoechest 33342 staining）來分析各組細胞週期（cell cycle）分佈及細胞凋亡（apoptosis）百分比，腫瘤細胞的轉移能力（cell metastasis capacity）則以傷口癒合試驗（wound healing assay）及細胞遷移與侵襲試驗（transwell assay）來評估。可能的機制則以西方墨點法（Western blotting）來分析調查。褪黑激素的治療顯著的減少T24及UMUC3膀胱癌細胞擴散與增殖能力（cell proliferation and clonogenic ability）。在褪黑激素作用下可見到T24及UMUC3膀胱癌細胞在細胞分裂的G1期停滯及sub-G1期積累，可抑制癌細胞的擴散及導致細胞凋亡。並進而由Hoechst 33342核染色試驗來證實褪黑激素可引發細胞凋亡。此外，褪黑激素可減少膀胱癌細胞移動及擴散能力。這些結果幫助我們闡明了褪黑激素可藉由抑制HIF-1α 及 NF-κB的途徑及其下游途徑，包含Bcl-2，導致膀胱癌細胞株細胞分裂停滯及啟動凋亡，造成在膀胱癌中的抗腫瘤作用。這些結果幫助我們闡明了褪黑激素在膀胱癌中的抗腫瘤作用，並為替代輔助治療提供了新的方向。

Urinary bladder urothelial carcinoma (UBUC) encompasses about 90% of all bladder cancer cases, and the mainstream treatment is the transurethral resection of the bladder tumor followed by intravesical instillation. High rates of mortality, recurrence, and progression in bladder cancer have stimulated the search for alternative adjuvant therapies. The aim of this study was to investigate the potential of melatonin as an adjuvant therapy in bladder cancer. Cell viability and clonogenic ability were assessed by an MTT assay and colony formation. Cell cycle and apoptosis analysis was performed by flow cytometry and Hoechst 33342 staining, while cell metastasis capacity was measured by wound healing and transwell assays. Potential mechanisms were investigated by an oncology array and verified via western blotting. The melatonin treatment significantly reduced T24 and UMUC3 bladder cancer cell proliferation and clonogenic ability. G1 arrest and sub-G1 accumulation in the T24 and UMUC3 cells led to cell proliferation suppression and cell death, and Hoechst 33342 staining further verified the apoptosis induction directly by melatonin. Moreover, melatonin weakened cell motility and invasiveness. Based on the oncology array results, we demonstrated that melatonin exerts its anti-cancer effect by down-regulating the HIF-1α and NFκB pathways and downstream pathways, including of Bcl-2, leading to cell cycle arrest and apoptosis induction in the UBUC cells. Overall, these findings support the potential of melatonin as an adjuvant therapy in bladder cancer.