Assessment of the radiation sensitivity of cervical cancer cell lines

The aim of radiotherapy is to kill tumor cells in a primary tumor, in draining lymph nodes, and/or in small metastatic lesions. The response of tumor cells to radiation depends on the dose, an individual's radiosensitivity, the duration of radiation exposure (i.e., the timing), the fraction size, and the presence of other variables (e.g., chemotherapy). Sensitivity of the cells to radiation can be determined by cell proliferation and clonogenicity assays, which assess the ability of the cells to survive at low cell densities and to successfully initiate and sustain cell proliferation over time yielding viable colonies or clones after irradiation with a range of doses (0-10Gy). Apart from assessing the sensitivity of the cells to radiation, these assays are now being increasingly used to test for the effects of drugs/genes on the growth and proliferative characteristics of cells in vitro. Additionally, they are being used to determine the combinatorial effect of novel agents or inhibitors, which can modify the response to radiation for a favorable therapeutic outcome. The rates of cell survival and proliferation obtained from these assays help in identifying the most sensitive and resistant cell lines among particular cancer types. Because of their wide range of application, from identifying the most sensitive and resistant cell lines, to evaluating novel therapeutic agents, we describe here the basic steps involved in assessing the radiosensitivity of cervical cancer cell lines.