EFFECTS OF RADIOTHERAPY AND CHEMOTHERAPEUTIC CYTOKINES ON A HUMAN SALIVARY CELL-LINE

Background. Various malignancies are treated with radiotherapy or chem otherapy, or a combination of both. Unfortunately, these therapies als o inflict damage to neighboring healthy tissues, such as salivary glan ds, during treatment for head and neck tumors. The purpose of this stu dy was to evaluate the possible interaction between radiotherapy and c hemotherapeutic cytokines [TNF-alpha and INF-gamma] on cell growth and survival; as well as IL-6 production in a human salivary cell line [H SG] and to examine the nature of salivary cellular death inflicted by the irradiation. Results. A pronounced inhibitory effect on HSG cell g rowth was demonstrated 72 hours following treatment of the cells with TNF-alpha [10 u/ml] and INF-gamma [1000 u/ml][69% p<0.01] or TNF-alpha [10 u/ml] and irradiation [15 Gy][66% p<0.01]. This reduction in cell viability was accompanied by a pronounced increase in IL-6 production by the cells. Seventy-two hours post-irradiation [15 Gy] the HSG cell death rate was 70-75%, in agreement with a delayed salivary reproduct ive cell death model which could explain the life-long xerostomia whic h often results In head and neck irradiated patients.