‘Cigarette smoke makes tumors more efficient as an ecosystem to promote cancer growth,’ says Thomas Jefferson University research
Researchers at Thomas Jefferson University (United States) demonstrated that cigarette smoke reprograms the cells surrounding cancer cells and thus helps boost the aggressiveness of head and neck cancer, the sixth most frequent type of tumor in the world, and It arises in the outer layer of the skin and the mucous membranes of the mouth, nose, and throat.
Tumors are composed of cancer cells that grow out of control and non-cancerous cells that ‘support’ the tumor. More than half of the tumor cells are support cells and create what scientists call the tumor stroma. The most common type of cell in the tumor stroma is fibroblasts, which help maintain tissue architecture.
Interactions between fibroblasts and cancer cells promote tumor growth. Cancer cells use metabolic products generated by surrounding fibroblasts to obtain energy and stimulate their growth. “That’s where the tumors are more aggressive,” the researcher details.
Knowing that cigarette smoke is the strongest risk factor for this type of cancer, the researchers set out to better understand how the metabolism of different tumor cells changes. To do this, they exposed the fibroblasts to tobacco. According to their study, fibroblasts increased a particular type of metabolism called glycolysis, which produces metabolites that are used by nearby cancer cells to help stimulate their growth.
In addition, these cancer cells acquired certain characteristics of malignancy, such as increased mobility and resistance to cell death. The increased support of fibroblasts exposed to tobacco-caused larger tumors in a mouse model of the disease. In addition, they also found a protein in fibroblasts exposed to tobacco that seemed to boost these metabolic changes.
This discovery has laid the foundations for a future clinical trial in which they hope to be able to ‘turn off’ the negative metabolic state induced by cigarette smoke. The study will combine an approved diabetes medication called metformin, which will target the altered metabolism of cancer cells, with approved immunotherapy called durvalumab.
CANCER AND TOBACCO FACTS
According to various experts, tobacco can be behind 60 percent of cancer deaths and its consumption is related to the appearance of eight tumors, which are usually more capable of mutating and are the most resistant to any treatment, in line with findings of this team of American researchers.
Spain is one of the European countries in which more tumors are diagnosed, although the incidence and mortality are in the European average. In lung cancer, specifically, up to 90 percent of diagnosed cases are associated with smoking, according to data from the Spanish Association of Lung Cancer Patients (AEACaP).
Every year 10 thousand new cases of head and neck tumors are detected in Spain. The most frequent types are those of the oral cavity, whose incidence is 3 percent, although it increases every year. Between 11 and 17 cases are detected per 100 thousand inhabitants. Globally, it is estimated that it produces 350,000 deaths every year in the world, and 85 percent of cases are due to tobacco use.