Genotoxic treatments elicit DNA damage response (DDR) not only in cells that are directly exposed but also in cells that are not in the field of treatment (bystander cells), a phenomenon that is commonly referred to as the bystander effect (BE). However, mechanisms underlying the BE remain elusive. We report here that etoposide and ultraviolet (UV) exposure stimulate the production of microvesi...

The observation of radiation-induced bystander responses, in which cells respond to their neighbors being irradiated, has important implications for understanding mechanisms of radiation action particularly after low-dose exposure. Much of this questions the current dogma of direct DNA damage driving response in irradiated systems. In this study, we have used a charged-particle microbeam to tar...

Radiotherapy is an important treatment option for many human cancers. Current research is investigating the use of molecular targeted drugs in order to improve responses to radiotherapy in various cancers. The cellular response to irradiation is driven by both direct DNA damage in the targeted cell and intercellular signalling leading to a broad range of bystander effects. This study aims to el...

An adaptive response may be defined as the effect of a small priming dose of radiation modifying the anticipated cellular response of the same tissues so as to alter the predicted response to a larger dose of radiation. We and others have demonstrated that at low radiation doses (less than 0.5 Gy) the lethal and mutational effect of the radiation is mainly, possibly entirely, due to the non-tar...

In the present study, ionizing radiation (IR)-induced bystander effects were investigated in two lung cancer cell lines. A549 cells were found to be more resistant to radiation-conditioned medium (RCM) obtained from A549 cells when compared with the H460 exposed to RCM procured from H460 cells. Significant release of tumor necrosis factor-alpha (TNF-alpha) was observed in A549 cells after IR/RC...

the immunosuppressive effect of antimacrophage serum (ams) on the primary immune response of mice to sheep red blood cells (srbc) was studied. ams, given before a small dose of antigen, abrogated the immune response. transplantation of normal, galss-adherent macrophages enabled ams-treated animals to respond to srbc, while administration of lymph node lymphocytes did not reveres ams - induced i...

Radiations in medicine cover a wide range of applications, predominantly diagnostic imaging and radiotherapy, encompassing photons (x- γ-rays) particle radiation, as well with the use liquid sources nuclear focusing on physiological functional imaging, tumour detection or targeted radiotherapy. The biological interactions ionizing radiation leads naturally to questions benefits risk following d...

introduction: radiation induced bystander effect (ribe) which cause radiation effects in non-irradiated cells, has challenged the principle according to which radiation traversal through the nucleus of a cell is necessary for producing biological responses. what is the mechanism of this phenomenon? to have a better understanding of this rather ambiguous concept substantial number of original an...

The bystander effect is a biological phenomenon whereby cells not directly targeted by DNA-damaging agents elicit a response similar to that of targeted cells. Understanding the mechanisms underlying the bystander effect is important not only for radiation risk assessment but also for evaluation of protocols for radiotherapy of tumors. Identification of DNA repair and signal transduction protei...

Suicide gene therapy of glioma based on herpes simplex virus type I thymidine kinase (HSV-TK) and prodrug ganciclovir (GCV) suffers from the lack of efficacy in clinical trials, which is mostly due to low transduction efficacy and absence of bystander effect in tumor cells. Recently, stem cells as cellular delivery vehicles of prodrug converting gene has emerged as a new treatment strategy for ...