Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India.
Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India.
Arch Biochem Biophys. 2021 Sep 15;708:108940. doi: 10.1016/j.abb.2021.108940. Epub 2021 May 28.
Nanomaterials, such as graphene oxide (GO), are increasingly being investigated for their suitability in biomedical applications. Tubulin is the key molecule for the formation of microtubules crucial for cellular function and proliferation, and as such an appealing target for developing anticancer drug. Here we employ biophysical techniques to study the effect of GO on tubulin structure and how the changes affect the tubulin/microtubule assembly. GO disrupts the structural integrity of the protein, with consequent retardation of tubulin polymerization. Investigating the anticancer potential of GO, we found that it is more toxic to human colon cancer cells (HCT116), as compared to human embryonic kidney epithelial cells (HEK293). Immunocytochemistry indicated the disruption of microtubule assembly in HCT116 cells. GO arrested cells in the S phase with increased accumulation in Sub-G1 population of cell cycle, inducing apoptosis by generating reactive oxygen species (ROS) in a dose- and time-dependent manner. GO inhibited microtubule formation by intervening into the polymerization of tubulin heterodimers both in vitro and ex vivo, resulting in growth arrest at the S phase and ROS induced apoptosis of HCT116 colorectal carcinoma cells. There was no significant harm to the HEK293 kidney epithelial cells used as control. Our report of pristine GO causing ROS-induced apoptosis of cancer cells and inhibition of tubulin-microtubule assembly can be of interest in cancer therapeutics and nanomedicine.
纳米材料，如氧化石墨烯（GO），因其在生物医学应用中的适用性而越来越受到关注。微管蛋白是形成对细胞功能和增殖至关重要的微管的关键分子，因此成为开发抗癌药物的有吸引力的靶标。在这里，我们采用生物物理技术研究 GO 对微管蛋白结构的影响，以及这种变化如何影响微管蛋白/微管组装。GO 破坏了蛋白质的结构完整性，从而导致微管蛋白聚合的延迟。研究 GO 的抗癌潜力时，我们发现它对人结肠癌细胞（HCT116）比对人胚肾上皮细胞（HEK293）更具毒性。免疫细胞化学表明，GO 破坏了 HCT116 细胞中的微管组装。GO 通过在 S 期诱导细胞周期中 Sub-G1 群体的积累来阻止细胞分裂，通过产生活性氧物种（ROS）以剂量和时间依赖的方式诱导细胞凋亡。GO 通过干预微管蛋白异二聚体的聚合，在体外和体内抑制微管形成，导致 HCT116 结直肠癌细胞在 S 期生长停滞和 ROS 诱导的细胞凋亡。作为对照使用的 HEK293 肾上皮细胞没有受到明显的伤害。我们的报告表明，原始 GO 会导致 ROS 诱导的癌细胞凋亡和微管蛋白/微管组装的抑制，这可能对癌症治疗和纳米医学有意义。
