Culture characters, genetic background, estrogen/progesterone receptor expression, and tumorigenic activities of frequently used sixteen endometrial cancer cell lines

Background: This study aimed to determine the in vitro and in vivo properties of sixteen frequently used endometrial cancer (EC) cell lines, including the cell proliferation rate, morphology, hormone receptor expression patterns, PTEN, hMLH1 expression, p53 mutation, karyotype, and tumorigenicity in mouse xenograt model.

Methods: Twelve type I (AN3, ECC-1, EN, EN-1, EN-11, HEC-1A, HEC1B, Ishikawa, KLE, MFE-280, MFE-296, MFE-319) and four type II (ARK1, ARK2, HEC-155/180, SPEC-2) endometrial cancer cell lines were studied. Cell proliferation and morphology were determined using cell growth curves and light microscopy, respectively. Real-time PCR was performed to measure the mRNA levels of target genes. Denaturing High Performance Chromatography (DHPLC) screening and PCR/sequencing were performed to identify p53 mutations. G-banding was applied for karyotyping. Tumorigenicity was evaluated using mouse xenograft.

Results: The population doubling time of the cell lines ranged between 19 and 41 h. Ishikawa, ECC-1, and MFE-280 have high while AN3 and EN1 have low expression of ER-α and ER-β. Expression of total PR and PR-B uniformly decreased in all type II cell lines and several type I cell lines (AN3, HEC-1A, HEC1B, KLE, EN-1). Regression analyses revealed significant correlations between PR-B and total PR (p < .001), between isoforms ER-α and ER-β (p < .001), and between total PR and ER (p < .001), mRNA levels in type I cell lines. p53 mutations were detected in exons 5-8 of seven out of twelve type I and one out of four type II cell lines. PTEN expression was more uniformly suppressed in type II than type I cells, while hMLH1 did not show this pattern. All the five cell lines tested contained severe karyotype abnormalities. Mouse xenograft results indicated that HEC-1A, HEC-1B and EN-1 type I as well as ARK1 and ARK2 type II cell lines had potent tumorigenic activities. Low PR-B and ER-α expression in type I cell lines were associated with high tumorigenic activity.

Conclusions: This study provides resource information on EC cell lines commonly used in laboratories, which could be used for choosing cell lines suitable for specific research purposes. The results of karyotype analysis and p53 mutation together with hormone receptor expression pattern and morphology comparison strongly suggested an independent nature of these cell lines, excluding the possibility of cross-contamination between cell lines. Additionally, this information suggests potential directions for future studies on the pathogenic mechanisms of endometrial cancer.