Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2019 Sep 26;9:13931. doi: 10.1038/s41598-019-50329-3

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© The Author(s) 2019

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

PMC Copyright notice

The principle of bystander signaling between tumor cells with inactivated catalase and untreated tumor cells. (A) The principle. Left side: In a mixture between tumor cells with inactivated membrane-associated catalase and untreated tumor cells the final percentage of apoptotic cells would be strictly correlated to the percentage of pretreated cells in the population. Right side: Experimental evidence has been provided^60,95,96 that tumor cells with inactivated catalase drive a singlet oxygen-mediated bystander signaling that causes inactivation of membrane-associated catalase, reactivation of intercellular RONS signaling and apoptosis induction. As a result, the percentages of apoptotic cells are much higher than to be expected from the percentage of pretreated cells in the mixedpopulation. (B) Quantitative analysis of bystander signaling. The percentage of apoptotic cells is much higher than the percentage of pretreated cells with inactivated catalase, when bystander signaling is effective. Inhibition of bystander signaling leads to percentages of apoptotic cells that strictly correlate with the percentages of pretreated cells. This system allows analysis of the underlying molecular mechanisms through application of defined inhibitors or scavengers at distince steps. It also allows to determine the percentage of bystander-inducing cells in a population through titration of cells from this population on untreated cells and determining the percentage of apoptotic cells. If the induction of bystander inducing potential is a rare effect, a large portion of a cell population will be needed to induce bystander signaling, whereas a population with a high percentage of bystander effect-inducing cells will allow bystander induction even with a low percentage of these cells within an untreated population.