The assesment of radiation therapy-resistant tumor response to the treatment with beta-glucan

Abstract

Introduction: Radiation therapy is one of the main treatment methods of cancer, but development of resistance to radiation therapy limits its treatment outcome. The aim of the study was to assess radiation therapy-resistant tumor response to the treatment modulation by beta-glucan, known as powerful immune stimulant and antagonist to malignant tumors. Methods: C57BL/6 female (8–10 weeks of age) radiotherapy- resistant Lewis lung carcinoma (LLC) tumor bearing mice were used. Mice were treated with radiotherapy or/and beta-glucan. Single radiotherapy (dose 10 Gy) or fractionated radiotherapy (2Gyx 5 days) have been applied. Tumor growth by measuring of tumor volume and mice survival were evaluated. Expression of the genes Bbc3, P21, Ccng1, ID1, Dcn, THBS2, influencing development of resistance, was determined by RT-PCR. Results: The lowest tumor volumes were in the group of mice treated with beta-glucan alone (P < 0.05). Tumor growth was suppressed more when fractionated radiotherapy with beta-glucan was applied than this with single dose radiotherapy (P < 0.05). The best survival was achieved in the group treated with beta – glucan. The expression of the genes increased after the radiation therapy similar as in 3D cell culture. Coadministration of beta-glucan doesn’t affect the expression level of the genes. Discussion: The tumor matrix may have a big influence to the development of the resistance to radiotherapy.