There are a number of questions that can be answered by analyzing the role of cancer stem cells in the tumor process. The first question is whether cancer stem cells are capable of self-renewal. Cancer stem cells are populations of cancer cells that have unrestricted capacity for self-renewal and asymmetric division. These cancer cells are responsible for maintaining and regrowing tumors even after treatment. Interestingly, cancer stem cells are found in many types of tumors, with varying levels of density. Various markers can help identify cancer stem cells and guide treatment.
Scientists are testing the effects of drugs currently on the market on cancer stem cells. For example, the immunosuppressive drug rapamycin has shown promising results in the fight against neuroblastoma stem cells, while the diabetes drug metformin has helped doxorubicin eliminate breast cancer stem cells. Cancer stem cell research has also increased since the first cancer stem cells were identified in 1990, and there is still much to learn about these cells.
There is a lot of speculation about the risks associated with different types of stem cells. Researchers used several cancer cell lines to study the effect of cancer stem cells. They used rat neuroblastoma cells, adenocarcinoma cell line (HeLa), and a human bone marrow cell line (MCF-7). The cells were cultured in a DMEM/F-12 medium supplemented with 10% FCS, 100 units/ml penicillin G, and 100 mg/ml streptomycin.
While the human telomerase reverse transcriptase (hTERT) is not detected in normal tissue, it is found to be expressed in cancer cells. Various tumor-specific genetic and epigenetic events have increased the expression of hTERT in cancerous tissues. The Bmi1 gene is responsible for stem cell renewal and up-regulation of hTERT in epithelial cells. These mutations are accompanied by decreased telomere length, which is associated with a higher risk of cancer.
Moreover, the persistence of the cancer stem cell compartment is a key factor in the recurrence of cancer. Chemotherapy-resistant tumor stem cells acquire drug resistance through various mechanisms, including genetic aberrations and mutations. While the presence of cancer stem cells may be an advantage in overcoming the resistance of tumors, chemotherapy-resistant cancer cells may pose a threat to the survival of the rest of the body.
Interestingly, the cancer stem cell model also applies to brain and nervous system cancers. The study found that a small subpopulation of cancer cells is capable of proliferating in vitro and forming tumors in vivo. Brain cancer stem cells in culture have the ability to form neurospheres, whereas the majority of tumor cells failed to form this pattern. This suggests that cancer stem cells have the potential to recur in the brain.
The findings in cancer stem cell research have several practical implications for the future of the field of oncology. These cells can recur in the original tumor and even metastasize to distant vital organs. They may also contribute to the development of resistance to chemotherapy and radiation. Therefore, cancer stem cells could be the Achilles’ heel of effective cancer treatments. To combat this, a new breed of therapies has been developed that destroy cancer stem cells and allow the tumor to die. Cancer stem cell research is constantly evolving and the discovery of new therapies will further our understanding of cancer stem cells and help to combat it.
