A new look at the origin of cancer
It has been proven that the progression of the tumor is associated with the division and differentiation of atypical cancer stem cells. A new study has shown that mature cells also play a role in tumor development.
A group of scientists from Washington University School of Medicine in St. Louis has proved that mature cells have the ability to turn into stem cells and behave like less differentiated cells. But, returning to the status of stem cells, they carry all the mutations that have accumulated during their lifetime. These mutations are the cause of the development of precancerous conditions.
Researchers pay a lot of attention to cancer stem cells as the main cause of cancer growth and metastasis. At the same time, according to the authors of the study, the role of mature cancer cells in these processes is undeservedly underestimated. The question of how tumor cells survive during cancer therapy remains open.
Most of the existing and developing methods of cancer treatment are aimed at stopping tumor growth by affecting rapidly dividing cells. The ability of mature cells to regain the status of stem cells is not taken into account.
Metaplasia expressing antispasmodic polypeptide (spasmolytic polypeptide-expressing metaplasia, SPEM) is a precancerous condition of the gastric mucosa caused by improper differentiation of stem cells. SPEM develops against the background of chronic atrophic gastritis caused by infection with the bacterium Helicobacter pylori. It has been proven that SPEM can degenerate into adenocarcinoma, a malignant tumor of the stomach.
In the study, SPEM was induced in mice using tamoxifen injection. The ability of stem cells to repair defects was blocked by intraperitoneal administration of 5-fluorouracil. The stomach was the most convenient site for research, as it is the easiest to identify mature and stem cells.
Based on molecular and histological analysis, it was found that even in the absence of stem cells, mice developed SPEM. As the researchers explain, this is due to the proliferation of mature cells, which under the created conditions acquired the properties of stem cells in order to close defects on the gastric mucosa.
Histological analysis of tissue samples of 10 people with gastric adenocarcinoma was performed. In humans, the same mechanisms were traced as in mice: SPEM did not arise from stem cells, but by direct reprogramming of existing cells, mainly due to the main stomach cells secreting pepsinogen.
Currently, work is underway to create a drug that could prevent precancerous lesions by blocking the transformation of mature cells back into stem cells. Researchers believe that this drug will work not only in the gastrointestinal tract, but also in other organs of the human body.
Article by Megan D. Radyk et al. Metaplastic Cells in the Stomach Arise, Independently of Stem Cells, via Dedifferentiation or Transdifferentiation of Chief Cells is published in the journal Gastroenterology.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of Washington University School of Medicine: Study prompts new ideas on cancers' origins.