Investigation on the direct and bystander effects in HeLa cells exposed to very low α-radiation using electrical impedance measurement

Ilyas, A. O., Alam, M. K., Musah, J.-D., Yang, M., Lam, Y. W., Roy, V. A. L. and Lau, C. (2021) Investigation on the direct and bystander effects in HeLa cells exposed to very low α-radiation using electrical impedance measurement. ACS Omega, 6(22), pp. 13995-14003. (doi: 10.1021/acsomega.0c05888) (PMID:34124424) (PMCID:PMC8190804)

Abstract

The impact of radiation-induced bystander effect (RIBE) is still not well understood in radiotherapy. RIBEs are biological effects expressed by nonirradiated cells near or far from the irradiated cells. Most radiological studies on cancer cells have been based on biochemical characterization. However, biophysical investigation with label-free techniques to analyze and compare the direct irradiation effect and RIBE has lagged. In this work, we employed an electrical cell-indium tin oxide (ITO) substrate impedance system (ECIIS) as a bioimpedance sensor to evaluate the HeLa cells’ response. The bioimpedance of untreated/nonirradiated HeLa (N-HeLa) cells, α-particle (Am-241)-irradiated HeLa (I-HeLa) cells, and bystander HeLa (B-HeLa) cells exposed to media from I-HeLa cells was monitored with a sampling interval of 8 s over a period of 24 h. Also, we imaged the cells at times where impedance changes were observed. Different radiation doses (0.5 cGy, 1.2 cGy, and 1.7 cGy) were used to investigate I-HeLa and B-HeLa cells’ radiation-dose-dependence. By analyzing the changes in absolute impedance and cell size/number with time, compared to N-HeLa cells, B-HeLa cells mimicked the I-HeLa cells’ damage and modification of proliferation rate. Contrary to the irradiated cells, the bystander cells’ damage rate and proliferation rate enhancements have an inverse radiation-dose-response. Also, we report multiple RIBEs in HeLa cells in a single measurement and provide crucial insights into the RIBE mechanism without any labeling procedure. Unambiguously, our results have shown that the time-dependent control of RIBE is important during α-radiation-based radiotherapy of HeLa cells.

• Item Type: Articles
• Additional Information: This work was supported by internal funding (from City University of Hong Kong).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Vellaisamy, Professor Roy
• Authors: Ilyas, A. O., Alam, M. K., Musah, J.-D., Yang, M., Lam, Y. W., Roy, V. A. L., and Lau, C.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: ACS Omega
• Publisher: American Chemical Society
• ISSN: 2470-1343
• ISSN (Online): 2470-1343
• Published Online: 26 May 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in ACS Omega 6(22): 13995-14003
• Publisher Policy: Reproduced under a Creative Commons License