Aims: HsMAD2 and BubR1 are crucial components of a functional mitotic checkpoint. Recently, impaired mitotic checkpoints or decreased expression of mitotic checkpoint genes have been associated with sensitivity to certain anticancer drugs. The current study aimed to evaluate the association of hsMAD2 and BubR1 with sensitivity to various anticancer drugs in oesophageal squamous cell carcinoma (ESCC) cell lines. We also investigated responses to 5-fluorouracil and cisplatin-based radiochemotherapy in ESCC patients.
Materials and methods: HsMAD2 and BubR1 mRNA levels in six ESCC cell lines and 21 ESCC patients were determined by real-time reverse transcription polymerase chain reaction. Responses to 5-fluorouracil, cisplatin, paclitaxel and docetaxel in human oesophageal cancer cell lines, TE1 and TE2, were evaluated by WST-8 colorimetric assay. HsMAD2 and BubR1 levels were compared with clinicopathological characteristics and responses to radiochemotherapy.
Results: TE1, with lower hsMAD2 and BubR1, showed greater sensitivity to paclitaxel and docetaxel compared with TE2, with higher hsMAD2 and BubR1. HsMAD2 and BubR1 were significantly higher in cancer tissue than in adjacent normal tissue (P < 0.01). Tumoral hsMAD2 and BubR1 were significantly decreased after radiochemotherapy (P < 0.01). There was a significantly strong positive association between hsMAD2 and BubR1 in cancer tissue (P < 0.01). Neither clinicopathological characteristics nor the response to radiochemotherapy was associated with hsMAD2 or BubR1.
Conclusion: The mitotic checkpoint genes, hsMAD2 and BubR1, were co-ordinately overexpressed in ESCC. Low hsMAD2 and BubR1 was associated with sensitivity to paclitaxel and docetaxel. Decreased hsMAD2 and BubR1 after radiochemotherapy may indicate the potential efficacy of taxanes as second-line chemotherapy for recurrent and metastatic oesophageal cancer.