PEGylated Paclitaxel Nanomedicine Meets 3D Confinement: Cytotoxicity and Cell Behaviors
Wenhai Lin#, Yuanhao Xu#, Xiao Hong, and Stella W. Pang*
#These authors contributed equally
*Corresponding Author
Dr. W. Lin, Dr. Y. Xu, X. Hong and Prof. S. W. Pang
Department of Electrical Engineering
City University of Hong Kong
Hong Kong, China E-mail: pang@cityu.edu.hk
Keywords: nanomedicine, microwell, paclitaxel, cell migration, 3D confinement
It is beneficial to investigate the effect of nanomedicines on cancer cell behaviors on three-dimensional (3D) platforms for evaluating and developing novel antitumor nanomedicines in vitro . Two-dimensional flat surface is widely used to study the cytotoxicity of nanomedicines on cancer cells, and there is little work using 3D confinement to assess the effect of nanomedicine on cancer cells. In this work, PEGylated paclitaxel nanoparticles (PEG-PTX NPs) were applied for the first time to treat nasopharyngeal carcinoma (NPC43) cells in 3D confinement which consisted of microwells with different sizes and a glass cover. The cytotoxicity of the small molecule drug paclitaxel (PTX) and PEG-PTX NPs were studied in microwells with sizes of 50×50, 100×100, and 150×150 μm2 and with covers. After NPC43 cells were treated with PTX and PEG-PTX NPs, the cell migration speed and cell morphology were analyzed in different microwells without and with covers. The relationship between the cytotoxicity from drugs, the size effect from microwells, and cell behaviors were analyzed. These results not only show the effect of 3D confinement on cytotoxicity of nanomedicines and cell behaviors, but also provide a novel method to screen anticancer drugs and evaluate the cell behaviors in vitro .
1. Introduction
Nanoparticles (NPs) are widely used for many applications including catalysis, medicine, and sensors.[1-9]Nanoparticles applied in medicine, or nanomedicines, can overcome various limitations of small molecule drugs such as strong hydrophobicity, poor bioavailability, and big side effects.[10-20] Some nanomedicines have been available for clinical use, and many other nanomedicines are under clinical evaluation.[21, 22] Among these nanomedicines, two nanomedicines based on paclitaxel (PTX), marketed as Abraxane and Genexol-PM, are widely used in clinics for treating various cancers such as ovarian, head and neck, and non-small cell lung cancers.[22-26] To achieve successful preclinical evaluation of nanomedicines, three-dimensional (3D) platforms are more suitable as the common two-dimensional (2D) cell culture platforms on flat surface cannot mimic the complex 3D microenvironment in vivo .
To better test the cytotoxicity of small molecule drugs and nanomedicines in vitro , some 3D platforms were used.[27-39] Microwells were extensively used in cancer cell studies including immune cell meditated cancer treatment and anti-cancer drug response evaluation.[40-42]Microwells have also been used for help cancer cells to form spheroids to test the cytotoxicity of nanomedicines.[43, 44]However, most of these studies still focused on the collective influence of nanomedicines on the cancer cell population. Previous works have revealed a clear dependence of cancer cell susceptibility to treatments with the microwell sizes.[45, 46] Therefore, it is important to evaluate the effect of physical confinement by microwells on the effectiveness of nanomedicines in a single-cell level, such that the time dependent nanomedicine treatment on individual cancer cell could be better understood. To the best of our knowledges, this is the first study using 3D confinement with the cover on the top to evaluate the cytotoxicity of nanomedicine and cell behaviors after cancer cells are treated with nanomedicines.