Study On Expression And Function Of Cancer-Testis Antigen LDH-C4 In Nasopharyngeal Carcinoma

Objective: 1.To study the expression and clinical significance of LDH-C4 protein in nasopharyngeal carcinoma;2.To assess the effects of LDHC gene overexpression on the biological characteristics of CNE2 nasopharyngeal carcinoma cells as well as the underlying mechanism.Methods: 1.Expression level of LDH-C4 in 129 high-throughput nasopharyngeal carcinoma tissue microarray was detected by immunohistochemistry(IHC).According to the judge score,we evaluated the correlation between LDH-C4 expression and nasopharyngeal carcinoma clinical feature that included tissue differentiation,clinical diagnosis,stage,metastasis,initial onset and recurrence,and prognosis;2.Exogenous LDHC coding gene was introduced into monoclonal CNE2 nasopharyngeal carcinoma cells by lentivirus vector,and the monoclonal expression cell line was obtained by fluorescence microscopy and dilution method.Effects of LDH-C4 overexpression on proliferation,colony formation,migration and invasion of CNE2 nasopharyngeal carcinoma cells were respectively assessed by CCK-8 colorimetric assay,plate cloning,scratch assay,and Matrigel Transwell chamber,so that to investigate the effects of LDHC4 overexpression on the biological characteristics of CNE2 nasopharyngeal carcinoma cells;the changes of AKT/mTOR signal pathway-related proteins were detected by Western blotting.Result: 1.Results of immunohistochemistry assay based on high-throughput nasopharyngeal carcinoma tissue microarrays showed that LDH-C4 was mainly expressed in the cytoplasm of 88.4% nasopharyngeal carcinoma cells.Spearman correlation analysis showed that expression level of LDH-C4 was closely related to clinical stage and cervical lymph node metastasis in patients with nasopharyngeal carcinoma(all with P<0.05).Kaplan-Meier survival and log-rank test results showed that patients with high expression of LDH-C4 had significantly worse prognosis than those with low expression(P<0.05).2.Monoclonal LDH-C4 positive CNE2 cell line was successfully obtained.Data based on CCK-8 test,clone forming assay,Scratch test,and Matrigel Transwell chamber showed that LDH-C4 up-regulation in nasopharyngeal carcinoma cells increased cell growth,clone formation,invade and migrate;Western blot analysis confirmed that AKT and mTOR involved in AKT/mTOR signaling pathway were highly expressed corresponding to LDH-C4 upregualtion.Conclusions: 1.The expression level of LDH-C4 in nasopharyngeal carcinoma patients was significantly higher.LDH-C4 expression was associated with clinical stage and neck lymph node metastasis.LDH-C4 could be rated as an independent molecular marker in monitoring the prognosis of nasopharyngeal carcinoma,and high level of LDH-C4 in nasopharyngeal carcinoma predicts poor prognosis.2.LDH-C4 overexpression promoted proliferation,invasion and metastasis of CNE2 nasopharyngeal carcinoma cells in vitro.LDH-C4 may promote proliferation,invasion and metastasis of nasopharyngeal carcinoma cells by activating the Akt/mTOR signaling pathway.