Human metastatic breast cancer cells in the pleural fluid that fills part of the lungs. Image credit: Ed Uthman (CC BY 2.0)
Cancer cells may not limit themselves to the tissue or organ where they first formed. In some cases, the cells can spread to form tumors in new parts of the body. This process is known as metastasis, and because it is difficult to treat it causes the majority of cancer deaths. To develop new treatments, researchers are trying to learn more about the different steps involved in metastasis.
As cancer cells travel through the body they must adapt to the changing environments they encounter, and avoid detection and destruction by the immune system. To do so, they turn different genes on or off. When the cells reach their final destination tissue, they divide to form microscopic clusters, or ‘micrometastases’, that can grow into new tumors. Micrometastases can sometimes be eliminated by chemotherapy or radiation. Examining which genes are active in the micrometastases may help researchers to find other ways to kill these cancer cells before they can grow into larger tumors that are harder to treat.
Basnet et al. have developed a new tool called Flura-seq that documents which genes are active in small clusters of cells in the tissues of living animals. The tool was used to study how breast cancer cells form new tumors in the lungs and brains of mice. The results of the study reveal that lung and brain micrometastases have different patterns of gene activity. In particular, the cancer cells in the lungs turn on antioxidant genes. If they did not, they were killed by a condition known as oxidative stress. This suggests that hindering the activity of the antioxidant genes could help to stop tumors forming in the lungs.
Further studies that use the new Flura-seq technique could help researchers to learn more about the early stages of cancer and cancer metastasis. The technique could also be used to study gene activity in other small groups of cells as tissues develop and regenerate.
