Purpose: To address the relationship between the bystander effect and the adaptive response that can compete to impact on the dose– response curve at low doses. Materials and methods: A novel radiation apparatus, where targeted and non-targeted cells were grown in close proximity, was used to investigate these phenomena in C3H 10TK cells. It was further examined whether a bystander effect or an...

Generation of reactive oxygen species (ROS) has been observed in cancer cells treated with paclitaxel, but the underlying mechanisms and therapeutic implications remain unclear. In the present study, we showed that paclitaxel promoted ROS generation through enhancing the activity of NADPH oxidase (NOX) associated with plasma membranes. Treatment of breast cancer cells caused an increased transl...

Mammalian cells respond to ionization radiation by sending out extracellular signals to affect non-irradiated neighboring cells, which is referred to as radiation induced bystander effect. In the present paper, we described a phenomenon entitled the "rescue effects", where the bystander cells rescued the irradiated cells through intercellular signal feedback. The effect was observed in both hum...

The bystander effect is an intriguing phenomenon by which adjacent cells become sensitized to drug treatment during gene therapy with herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV). This effect is reported to be mediated by gap junctional intercellular communication (GJIC), and therefore, we postulated that upregulation of genes that facilitate GJIC may enhance the HSV-tk/GCV by...

A central paradigm in radiation biology has been that only cells ‘hit’ by a track of radiation would be affected to induce radiobiological consequences, and cells ‘not hit’ should not be. This is the basis of the current system for risk estimation of radiobiological effects. However, it has recently been challenged by so-called non-targeted effects, such as bystander effect, and such radiation-...

Although radiation-induced heritable damage in mammalian cells was thought to result from the direct interaction of radiation with DNA, it is now accepted that biological effects may occur in cells that were not themselves traversed by ionizing radiation but are close to those that were. However, little is known about the mechanism underlying such a bystander effect, although cell-to-cell commu...

A number of studies have shown that students are often more willing to participate in educational conversations online than in the classroom. However, other studies have shown that online environments have poor student participation Why is this the case? What causes participation to vary from one environment to another? To explore these phenomena, we borrow a concept from social psychology, the...

Ultraviolet C (UVC) irradiation (λ: 200-280 nm) causes release of several secretory cytokines responsible for inflammation. Our objective was to investigate whether inflammatory response was also induced in bystander cells. For this purpose, the conditioned medium containing the released factors from UVC irradiated A375 cells was used in this study to evaluate the expression of inflammatory mar...

Elucidating the biological effect of low linear energy transfer (LET), low-dose and/or low-dose-rate ionizing radiation is essential in ensuring radiation safety. Over the past two decades, non-targeted effects, which are not only a direct consequence of radiation-induced initial lesions produced in cellular DNA but also of intra- and inter-cellular communications involving both targeted and no...

Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-...