The effect of ionising radiation upon the cellular DNA
Journal Title: Współczesna Onkologia - Year 2005, Vol 9, Issue 7
Abstract
Ionising radiation applied in the therapy of tumour diseases, are inducing formation of various DNA damages. This can interact with DNA molecules and evoke alkaline ionisation and this is the direct effect or through radiolysis of water molecules present in the cell and this is the indirect effect. The molecular structure of water breaks down radiolysis under the influence of radiation. As a result of the water radiolysis, a very aggressive hydroxyl radical (•OH) arises. Numerous experimental data show that the hydroxyl radical is considered to be the main active form of oxygen responsible for the majority of DNA damages. The •OH radical attack upon DNA generates a whole range of DNA damage, among these modified bases. Some of these modified DNA bases have a considerable potential to damage the integrity of the genome. And the rise in the number of derivatives is the consequence of this process. Some of these lesions may lead to mutagenesis, carcinogenesis and reproductive cell death. Reaction with the chromatin DNA induces single and double-strand breaks in DNA. The free radicals generating in the direct neighbourhood of chromatin can lead to the creation of DNA-protein cross-link. Occurence of such damages leads to disorders of the chromatin structure, which can influence the processes of repair, replication and transcription of DNA in both normal cells and tumour. It is supposed that only the damage of coding places in DNA can make a lethal damage of a cell. Moreover, it is considered that parts of DNA devoid of nuclear proteins are most sensitive to damages caused by ionising radiation.
Authors and Affiliations
Krzysztof Roszkowski, Marek Foksiński
Keywords
Related Articles
- EP ID EP112730
- DOI -
- Views 72
- Downloads 0
Autologous hematopoietic cell transplantation in adult patients with germ cell tumors and soft tissue sarcomas
The prognosis of recurrent or refractory solid tumors is dismal and few patients have experienced prolonged survival. For patients with metastatic neuroblastoma or Ewing`s sarcoma treated conventionally, the prognosis fo...
The role of IMRT in reduction of the rectal dose during radiotherapy of prostate cancer
Introduction: Several clinical studies revealed that doses higher than 70 Gy may be desirable to improve local control in prostate cancer. Rectal toxicity appears to be most clinically relevant and dose-limiting organ fo...
Przeszczepianie komórek krwiotwórczych od dawców allogenicznych: wyniki leczenia na podstawie doświadczenia Dolnośląskiego Centrum Transplantacji Komórkowych z Krajowym Bankiem Dawców Szpiku
Przeszczepianie macierzystych komórek krwiotwórczych (HSCT) od allogenicznego dawcy jest postępowaniem z wyboru w leczeniu części chorych z ciężkimi niedoborami tkanki krwiotwórczej i nowotworami tego układu. Analiza k...
Cervix cancer brachytherapy: time for changes?
Radiotherapy, currently administered together with cisplatin, is beside surgery the main method of most invasive cervical cancer treatment. This modality consists of external beam irradiation and brachytherapy. In the ai...
Immunotherapy of colon cancer
Despite many difficulties, immunotherapy of colon cancer becomes more effective and slowly enters into everyday clinical practice. The long way from unspecific immune stimulators such as levamisole, BCG, interleukins and...