O'Callaghan Kate, Palagano Eleonora, Butini Stefania, Campiani Giuseppe, Williams D Clive, Zisterer Daniela M, O'Sullivan Jeff
School of Dental Science, Trinity College Dublin, Dublin 2, Ireland.
School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
Mol Med Rep. 2015 Sep;12(3):3748-3754. doi: 10.3892/mmr.2015.3832. Epub 2015 May 25.
Oral cancer (OC) is a largely asymptomatic disease, resulting in one of the highest mortality rates of any cancer. OC is currently ranked as the sixth most common cancer in the world, according to a recent World Health Organization analysis, and its prevalence is increasing, both in western and developing regions. Depending on the stage of OC, treatment strategies include surgery, radiation therapy and chemotherapy, or a combination thereof. As with numerous other types of cancer, resistance to conventional chemotherapeutic drugs is increasing in oral squamous cell carcinoma (OSCC). The present study aimed to investigate the use of a novel group of compounds, the pyrrolo‑1,5‑benzoxazepines (PBOXs), as a therapeutic alternative for the treatment of OC. PBOXs are microtubule‑targeting agents that are able to induce apoptosis in numerous cancer cell types, thereby preventing tumour cell proliferation. Ca9.22 gingival and TR146 buccal cell lines were used as models for OSSC. Cell viability and proliferation in the presence of two PBOXs: PBOX‑6 and PBOX‑15, was monitored using an AlamarBlueTM assay. Flow cytometric analysis of propidium iodide‑stained cells was used to determine the DNA content, and therefore the percentage of cells in each phase of the cell cycle. Microtubule disruption was determined by indirect immunofluorescence staining. Changes in protein expression and degradation were determined by western blotting. The results of the present study indicated that both PBOX‑6 and ‑15 were able to induce apoptotic cell death by disrupting the microtubule network in both cell lines. The EC50 values were subsequently calculated for both PBOX‑6 and ‑15, and PBOX‑15 was shown to possess a higher potency. Both compounds displayed anti‑proliferative effects mediated through sustained G2/M arrest accompanied by tubulin disruption, and a decrease in DNA repair protein poly (ADP ribose) polymerase expression. These findings suggest that PBOXs may prove useful, either alone or in combination with other agents, in the treatment of chemotherapeutic resistant OSCC.
口腔癌（OC）在很大程度上是一种无症状疾病，导致其成为所有癌症中死亡率最高的癌症之一。根据世界卫生组织最近的一项分析，OC目前是世界上第六大常见癌症，并且在西方和发展中地区其发病率都在上升。根据OC的阶段，治疗策略包括手术、放射治疗和化疗，或这些方法的联合使用。与许多其他类型的癌症一样，口腔鳞状细胞癌（OSCC）对传统化疗药物的耐药性正在增加。本研究旨在调查一类新型化合物——吡咯并[1,5]苯并二氮杂卓（PBOXs）作为治疗OC的替代疗法的用途。PBOXs是微管靶向剂，能够在多种癌细胞类型中诱导凋亡，从而防止肿瘤细胞增殖。Ca9.22牙龈细胞系和TR146颊细胞系用作OSCC的模型。使用AlamarBlueTM测定法监测在两种PBOXs（PBOX-6和PBOX-15）存在下的细胞活力和增殖。使用碘化丙啶染色细胞的流式细胞术分析来确定DNA含量，从而确定细胞周期各阶段的细胞百分比。通过间接免疫荧光染色确定微管破坏情况。通过蛋白质印迹法确定蛋白质表达和降解的变化。本研究结果表明，PBOX-6和-15均能够通过破坏两种细胞系中的微管网络诱导凋亡性细胞死亡。随后计算了PBOX-6和-15的半数有效浓度（EC50）值，结果显示PBOX-15具有更高的效力。两种化合物均表现出通过持续的G2/M期阻滞介导的抗增殖作用，伴有微管蛋白破坏以及DNA修复蛋白聚（ADP核糖）聚合酶表达降低。这些发现表明，PBOXs可能单独或与其他药物联合用于治疗化疗耐药的OSCC时是有用的。
