Chlamydia may contribute to the development of cancer
They got to cancer sexually
Polina Rozentsvet, <url>Chlamydia trachomatis bacteria are the cause of most sexually transmitted diseases.
90 million people are infected with them every year. The widespread spread of chlamydia infection is caused primarily by the fact that it is asymptomatic for a long time. But the bacterium is by no means harmless: most often chlamydia affects the external and internal genitalia, but can also damage the mucous membrane of the respiratory tract, the heart, the inner wall of blood vessels, joints, teeth, organs of vision and hearing.
The other day, the list of C.trachomatis' transgressions was supplemented with another serious accusation: researchers from the Max Planck Society Institute of Infection Biology (Berlin) proved that chlamydia infection contributes to the development of malignant tumors.
Epidemiologists have long noted the connection of chlamydia infection with the development of cervical and ovarian cancer. German scientists have established the molecular mechanism of this connection. In a paper published in the journal Cell Host & Microbe (Chumduri et al., Chlamydia Infection Promotes Host DNA Damage and Proliferation but Impairs the DNA Damage Response, they showed how the pathogen stimulates the occurrence of DNA damage in the patient's cells and prevents the repair of these damages.
Chlamydia is an intracellular parasite. It spends most of its life cycle in its host's cell, outside of which it cannot reproduce. For growth and development, chlamydia need proteins that only the host cell can provide them, so the parasite affects the synthesis of host proteins in order to achieve the desired result for itself.
Chlamydia can be likened to a tenant who settles in someone else's house, rearranging furniture there to his liking. Naturally, such permutations cannot pass without a trace. Actually, German researchers were just interested in the effect of the activity of the bacterium on the state of the host.
The scientists worked with cultures of human fallopian tube epithelial cells and human fibroblasts (connective tissue cells), which were infected with chlamydia. It turned out that intracellular parasites act in several directions at once. They release reactive oxygen species in large quantities, which damage the host DNA, including causing its breaks. In addition, infection in a complex way (researchers have found out how) affects the work of certain genes. As a result of these changes, the cell cannot repair the damage received: proteins that should be engaged in repair do not get to the place of work.
DNA damage of varying severity occurs all the time, but usually the cell corrects them. If the damage is so serious that it is not possible to eliminate them, the cell turns on the mechanism of apoptosis and decorously dies. But chlamydia does not allow the host to patch up DNA breaks, nor to die with dignity. By influencing the activity of genes, bacteria stimulate cell division, which transmit their defective DNA to daughter cells.
As a result, the number of cells in the host's body that carry serious mutations and are unable to correct them is growing, and this is a sign of cancer. Thus, an intracellular parasite creates conditions for the formation of a malignant tumor.
This process takes time, but chlamydia has enough of it. As we have already said, the infection is often asymptomatic, so sick people may not see a doctor for years. In addition, chlamydia resistant to drugs have already appeared, so that after treatment the disease can turn into a chronic form.
The list of infectious agents that cause malignant tumors is constantly growing. It is known, for example, that the human papillomavirus stimulates the development of cervical cancer, and the bacterium Helicobacter pylori causes stomach cancer. Now this list has been supplemented by C.trachomatis. Perhaps vaccination against chlamydia or effective drugs against them could resist the development of malignant tumors, but first it is necessary to describe in more detail the path from infection to cancer. The authors of the study note that their result is just a piece of the puzzle to be put together.
Portal "Eternal youth" http://vechnayamolodost.ru24.06.2013