The innovation of cancer treatment technology has inspired patients' determination to fight cancer actively. However, poor treatment and recurrence have made many patients fall back into despair.
why cancer is so hard to cure and easy to relapse?
On January 7, 2021, a study published in the top international academic journal Cell gives an explanation.
Research shows that:
When threatened (such as chemotherapy), cancer cells enter a "dormant state" of slow division, greatly reducing their metabolism; at the same time, they activate autophagy (Autophagy), which can survive without other nutrients by breaking down their own proteins or other components. Wait until the threat is lifted and then make a comeback.
The research team from Canada combined cell barcodes and mathematical modeling in cancer cells from colorectal patients to determine and characterize persistent drug tolerance (DTP) status in response to chemotherapy.
The researchers cultured some tumor cells from patients with colon cancer in a petri dish and treated them with chemotherapy drugs. This chemotherapy treatment causes all cancer cells to enter a state of slow division that stops proliferation, in which cancer cells can survive with little nutrition. As long as chemotherapy continues, cancer cells will remain in this low-energy state, which the team calls the "diapause DTP state."
The team further found that cancer cells that slowly divide into this "diapause DTP state" activate their own autophagy in the face of chemotherapy stress. In this process, cancer cells break down and use their own proteins or other cellular components through autophagy to survive without nutrients. In other words, cancer cells recycle their own proteins or cellular components in order to survive the harsh environment caused by chemotherapy.
For this process, the researchers drew an analogy: think of the cancer cell as a bear. Chemotherapy is like winter when the bear goes into hibernation and wakes up. Similarly, after stopping the use of chemotherapy drugs, the cancer cells will proliferate at full speed again.
The team also tested an autophagy inhibitor, a small molecular compound that interferes with cancer cells' autophagy. The final test results show that after being inhibited autophagy, these cancer cells will not survive; after losing the energy supplied by autophagy, chemotherapy can easily kill these cancer cells.
This study not only provides a new way to deal with chemotherapy resistance, but also provides a new direction for overcoming cancer.
Drug resistance exists in almost all types of cancer and all anticancer drugs. In addition to chemotherapy, molecular-targeted therapy and immunotherapy can also produce drug resistance.
Studies have found that some chemotherapeutic drugs can enhance tumor immunogenicity. Radiotherapy can regulate tumor phenotype, enhance antigen presentation and tumor immunogenicity, increase chemokine release and recruitment of effector T cells to immune checkpoint inhibitors, and play a synergistic immune anti-tumor effect.
Immunotherapy combined with targeted therapy can not only kill tumor cells but also induce immune effects in tumor cells, patients' immune system, and tumor microenvironment.
At present, there is more and more evidence that tumors after the failure of one immunotherapy can respond to another immune checkpoint inhibitor due to the different drug resistance mechanisms of different immunotherapy.
