How do Radiosensitizers work?

How do Radiosensitizers work?

Radiosensitizers are chemicals or pharmaceutical agents that can enhance the killing effect on tumor cells by accelerating DNA damage and producing free radicals indirectly. In most cases, radiosensitizers have less effect on normal tissues.

How does chemotherapy work as a radiosensitizer?

It has been used clinically for many years as a chemo-radiosensitizer, long before it was realized it had preferential effects against hypoxic cells. It is activated by bioreduction to form products that crosslink DNA and therefore produce cell killing.

Which drug is considered a radiosensitizer?

Hypoxic cell sensitizers are able to increase the radiosensitivity of tumor cells deficient of oxygen by inducing the formation and stabilization of DNA-toxic radicals, mimicking the effect of oxygen. These drugs include nitroimidazole, misonidazole, etanidazole, nimorazole, and efaproxaril.

How does cisplatin work with radiation?

A clear synergistic interaction between cisplatin and ionizing radiation (IR) is observed in cells proficient in non-homologous end joining (NHEJ) catalyzed repair of DNA double-strand breaks (DSB). In contrast, no interaction between cisplatin and IR is observed in NHEJ deficient cells.

What is the purpose of a radiosensitizer?

A radiosensitizer, or a radiosensitizing agent, is a drug that makes cancer cells more vulnerable to radiation therapy. Radiation therapy uses high-energy radiation to shrink tumors by disrupting the DNA of cancer cells, causing them to die.

Which chemotherapy drugs are Radiosensitizers?

Etiology and Biocharacteristics. Radiation sensitizers include primarily traditional chemotherapy agents (i.e., gemcitabine, interferon-α, 13-cis-retinoic acid, doxorubicin, docetaxel, carboplatin, cisplatin, dactinomycin, methotrexate, 5-FU, bleomycin, and hydroxyurea).

What is an example of a radiosensitizer?

Examples of radiosensitizers include fluorouracil (5-FU, Adrucil) and cisplatin (Platinol). Amifostine (Ethyol) is an example of a radioprotector.

Is oxygen a radiosensitizer?

Oxygen is a potent radiosensitizer, increasing the effectiveness of a given dose of radiation by forming DNA-damaging free radicals. Tumor cells in a hypoxic environment may be as much as 2 to 3 times more resistant to radiation damage than those in a normal oxygen environment.

Is chemotherapy a radiosensitizer?

Radiosensitizers can be drugs that kill or inhibit growth of cancer cells, like chemotherapy, or drugs that only kill cancer cells when combined with radiation, says David Kozono, MD, PhD, radiation oncologist at Dana-Farber/Brigham and Women’s Cancer Center.

Which cells are the most radiosensitive?

Amongst the body cells, the most sensitive are spermatogonia and erythroblasts, epidermal stem cells, gastrointestinal stem cells. The least sensitive are nerve cells and muscle fibers. Very sensitive cells are also oocytes and lymphocytes, although they are resting cells and do not meet the criteria described above.