Establishment and characterization of a cell line (KGK) derived from human oral squamous cell carcinoma

Abstract

A new tumor cell line designated KGK was established from a metastatic submandibular lymph node of a patient who had a gingival squamous cell carcinoma. It has been continuously subcultured 350 passages during 6 years and 2 months. KGK cells showed a polygonal shape and grew in multiple layers without contact inhibition. Scanning electron microscopy indicated that KGK cells had numerous microvilli and intercellular bridges. Transmission electron microscopic observation exhibited cells that were joined by desmosomes. The population doubling time of KGK cell line was 19hr, and the saturation density was 9.3×10⁵ cells/cm². The planting efficiency on plastic dishes was 19%, and the colony-forming ability in semi-solid agar was 6.4%. The chromosomal number ranged around 62, and no abnormal karyotype was found in G-band staining. Inoculation of the KGK cells into BALB/c nude mice resulted in tumor formation which histologically closely resembled the original structure of the poorly differentiated squamous cell carcinoma.
We also examined the binding capability of epidermal growth factor (EGF) and the effect on growth in KGK cell line. Scatchard analysis of [¹²⁵I]-EGF binding indicated 2 components with high (5nM) and low (2nM) sites. The total number of EGF receptors per cell was 3 × 10⁵ sites/cell. The effect of EGF on growth was studied by the incorporation of [³H]-thymidine. The inhibitory activities of 1.0 and 10.0 ng/ml of EGF on the proliferation of KGK cell line were 62.7% and 68.7%, respectively.