Necroptosis triggered by ROS accumulation and Ca2+ overload, partly explains the inflammatory responses and anti-cancer effects associated with 1Hz, 100 mT ELF-MF in vivo

Mojdeh Barati; Mohammad Amin Javidi; Behrad Darvishi; Seyed Peyman Shariatpanahi; Zahra S Mesbah Moosavi; Reyhane Ghadirian; Tahereh Khani; Hassan Sanati; Hossein Simaee; Mahdieh Shokrollahi Barough; Leila Farahmand; Alireza Madjid Ansari

doi:10.1016/j.freeradbiomed.2021.04.002

Necroptosis triggered by ROS accumulation and Ca²⁺ overload, partly explains the inflammatory responses and anti-cancer effects associated with 1Hz, 100 mT ELF-MF in vivo

Free Radic Biol Med. 2021 Jun:169:84-98. doi: 10.1016/j.freeradbiomed.2021.04.002. Epub 2021 Apr 18.

Affiliations

¹ Integrative Oncology Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran.
² Recombinant Proteins Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran.
³ Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
⁴ Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
⁵ ATMP Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran.
⁶ Integrative Oncology Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran. Electronic address: majidansari@acecr.ac.ir.

PMID: 33857627
DOI: 10.1016/j.freeradbiomed.2021.04.002

Abstract

Whereas the anti-neoplastic activity of extremely low frequency magnetic fields (ELF-EMF) is well-documented in literature, little is known about its underlying anti-cancer mechanisms and induced types of cell death. Here, for the first time, we reported induction of necroptosis, a specific type of programed necrotic cell death, in MC4-L2 breast cancer cell lines following a 2 h/day exposure to a 100 Hz, 1 mT ELF-EMF for five days. For in vivo assessment, inbred BALB/c mice bearing established MC-4L2 tumors were exposed to 100 mT, 1 Hz ELF-EMF 2 h daily for a period of 28-day, following which tumors were dissected and fixed for evaluation of tumor biomarkers expression and types of cell death induced using TUNEL assay, Immunohistochemistry and H&E staining. Peripheral blood samples were also collected for assessing pro-inflammatory cytokine profile following exposure. An exaggerated proinflammatory response evident form enhancement of IFN-γ (4.8 ± 0.24 folds) and TNF-α (3.1 ± 0.19 folds) and number of tumors infiltrating lymphocytes (TILs), specially CD8⁺ T_h cells (~20 folds), proposed occurrence of necroptosis in vivo. Meanwhile, exposure could effectively suppress tumor growth and expression of Ki-67, CD31, VEGFR2 and MMP-9. In vitro studies on ELF-EMF exposed MC-4L2 cells demonstrated a meaningful increase in phosphorylation of RIPK1/RIPK3/MLKL proteins and cleavage of caspase-9/caspase-3, confirming occurrence of both necroptosis and apoptosis. Complementary in vitro studies by treating ELF-EMF exposed MC-4L2 cells with verapamil (a calcium channel inhibitor), N-acetyl cysteine (a ROS scavenger) or calcium chloride confirmed the role of elevated intracellular calcium and ROS levels in ELF-EMF induced necroptosis.

Keywords: Calcium; Extremely low frequency magnetic field; MLKL; Necroptosis; RIPK1; RIPK3; ROS.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Electromagnetic Fields
Mice
Mice, Inbred BALB C
Necroptosis*
Neoplasms*
Reactive Oxygen Species

Substances

Reactive Oxygen Species