A study on the contact effects producing radioresistance of uterine adenocarcinoma

Intercellular connection of uterine adenocarcinoma cells grown as spheroids was studied comparing to radioresistance. HEC-59 (uterine corpus adenocarcinoma) and SKG-3a (uterine squamous cell carcinoma) were used. The spheroids were produced by Yuhas's method. In monolayer culture, D0, Dsub(q) and n values in Hit theory were as follows: HEC-59 (D0 = 1.6 Gy, Dsub(q) = 0.6 Gy, n = 1.5), SKG-3a (D0 = 1.3 Gy, Dsub(q) = 0.4 Gy, n = 1.4). As spheroids with 300 μm diameter, survival curves of SKG-3a cells demonstrated a biphasic curves after acute irradiation. HEC-59 cells did not demonstrate the second component. This proved that SKG-3a spheroid has more hypoxic element than HEC-59 one. Where both cells grown as spheroids with 300 μm diameter were fractionately irradiated. SKG-3a spheroids were disintegritied upto 63 Gy at total dose but HEC-59 kept as spheroids over 70 Gy. The total dose of 50 % disintegrity was 40 Gy in SKG-3a and 48 Gy in HEC-59 spheroid. Radiation-induced detouchment of intercellular contact in adenocarcinoma cells was 1.2 times less than in squamous cell. Electron microscopic findings demonstrated that HEC-59 cells grown as a spheroid equiped chiefly junctional complexes but SKG-3a cells did desmosomes. This suggests that intercellular connection may play an important role to produce radioresistance in uterine adenocarcinoma cells grown as a solid tumor. (author)