Cüce-Aydoğmuş Esra M, İnhan-Garip G Ayşe
School of Medicine, Biophysics Department, T.C. Maltepe University, Maltepe, İstanbul, Turkey.
School of Medicine, Biophysics Department, T.C. Marmara University, Maltepe, İstanbul, Turkey.
Cancer Rep (Hoboken). 2024 Dec;7(12):e70072. doi: 10.1002/cnr2.70072.
Paclitaxel (PTX) has been used as a chemotherapeutic agent for several malignancies, including breast cancer, and efforts to increase the efficiency of PTX are continuous. Previous studies have shown that the voltage-gated K channels are over-expressed in breast cancer cell lines; therefore, blocking this type of K channel reduces cell proliferation and viability.
In this study, FDA-approved 4-aminopyridine (4-AP), a voltage-gated potassium channel blocker, was used in combination with PTX to improve the anticancer activity of PTX in MCF-7 and MDA-MB-231 cell lines.
Viability was determined with trypan blue, a clonogenic assay was performed, and the cell cycle was determined with a flow cytometer and immunochemistry. To gain an insight into the mechanism, intracellular K concentration, intracellular Ca (calcium) concentration, and transmembrane potential measurements were made with corresponding fluorescent dyes. The apoptotic cell number was determined using Annexin /PI method by flow cytometer. Viability decreased with combination therapy and the clonogenic assay proved decreased colony formation. The apoptotic cell number was increased after treatment with the combination in both cell lines. Cell cycle measurements showed G arrest for both MCF-7 and MDA-MB-231 cell lines upon 4-AP treatment. PTX caused G arrest in MCF-7 cells and S phase arrest in MDA-MB-231 cells. Combination treatment caused S phase arrest in MCF-7 cells and S phase and G/M phase arrest in MDA-MB-231 cells. Intracellular K concentration was increased after all treatments in both cell lines. Ca concentration was increased significantly after combination treatment. Depolarization in the transmembrane potential was observed after all treatments in both cell lines.
Biophysical parameters like the transmembrane potential and ion fluxes have been defined in cancer progression which can provide new aspects for cancer treatments. This study shows that the combination of 4-AP with PTX is a promising alternative the mechanism of which needs further investigation considering the results obtained for Ca, K, and membrane potential.
紫杉醇（PTX）已被用作多种恶性肿瘤的化疗药物，包括乳腺癌，并且提高PTX疗效的努力一直在持续。先前的研究表明，电压门控钾通道在乳腺癌细胞系中过度表达；因此，阻断这类钾通道可降低细胞增殖和活力。
在本研究中，美国食品药品监督管理局（FDA）批准的电压门控钾通道阻滞剂4-氨基吡啶（4-AP）与PTX联合使用，以提高PTX对MCF-7和MDA-MB-231细胞系的抗癌活性。
用台盼蓝测定细胞活力，进行克隆形成试验，并用流式细胞仪和免疫化学方法测定细胞周期。为深入了解其机制，用相应的荧光染料测量细胞内钾浓度、细胞内钙浓度和跨膜电位。用流式细胞仪通过膜联蛋白/碘化丙啶（Annexin /PI）法测定凋亡细胞数。联合治疗使细胞活力降低，克隆形成试验证明集落形成减少。两种细胞系经联合治疗后凋亡细胞数均增加。细胞周期测量显示，4-AP处理后，MCF-7和MDA-MB-231细胞系均出现G期阻滞。PTX使MCF-7细胞出现G期阻滞，使MDA-MB-231细胞出现S期阻滞。联合治疗使MCF-7细胞出现S期阻滞，使MDA-MB-231细胞出现S期和G/M期阻滞。两种细胞系经所有处理后细胞内钾浓度均升高。联合治疗后钙浓度显著升高。两种细胞系经所有处理后均观察到跨膜电位去极化。
跨膜电位和离子通量等生物物理参数在癌症进展中已有定义，可为癌症治疗提供新的方向。本研究表明，4-AP与PTX联合使用是一种有前景的替代方案，考虑到钙、钾和膜电位的研究结果，其作用机制需要进一步研究。
