Identification Of High Frequency Amplification Gene IGHMBP2 And The Study Of Its Function In Esophageal Squamous Cell Carcinoma

Objective: sophageal squamous cell carcinoma(ESCC) is one of the common malignant tumors in China and its mortality rate fourth in malignant tumors and threatens human health seriously. ESCC, because of its high incidence of lymph node metastasis and invasion of adjacent organs such as the aorta, trachea, bronchus and lung, often has poor prognosis and leads to the failure of treatment. Therefore looking for related genes with migration and invasion and studying preliminarily on its function is one of the main direction of study. This present study aims to explore the amplification status of IGHMBP2 and study its potential role in ESCC. This paper analyzed the amplification of IGHMBP2 in ESCC tissues, and detected the amplification and protein expression expression in cell lines. Then the changes of the invasion and migration abilities of cells were detected after knocking down and transinfecting plasmid. Finally we detected the change of proteins expression level related to invasion and apoptosis. Methods: We selected 59 cases of ESCC specimens and 8 ESCC cell line as the research objects. Array-CGH, Fluorescence In-Situ Hybridization and western blot was used to detect the amplification and expression levels of IGHMBP2 in ESCC. Transwell experiments were carried out to estimate invasion and migration ability of cell treated with si RNA and pc DNA3.1-IGHMBP2. MTS method was used to detect the knock down effect of IGHMBP2 on esophageal carcinoma cell proliferation. Western blot was used to detect the expression levels of protein related to invasion and migration. Results: Our previously reported array-CGH data were further analysed and found that IGHMBP2 was amplified in primary ESCC tumors and its rate is 28.9%(17/59). By means of fluorescence in-situ hybridization(FISH) and Western blot, we observed that IGHMBP2 were amplified/gained and highly expressed in esophageal cancer KYSE30, KYSE180,KYSE510 and KYSE150 cell lines. Transwell assays showed that knockdown of IGHMBP2 inhibited cell invasion and migration of KYSE30 and KYSE150(P < 0.001). When transfecting plasmid into knockdown groups of KESE30 and KYSE150, the protein expression level and the ability of invasion and migration of cells was restored(P < 0.01). After tranfecting pc DNA3.1-IGHMBP2 plasmids into COLO680 N which exhibits low IGHMBP2 expression level, the protein expression level and the ability of invasion and migration both increased. The effect of knock down of IGHMBP2 on the proliferation of KYSE30 and KYSE150 was detected in MTS method and results showed that there was no effect on the proliferation in the first two days, thus eliminating the influence of invasion and migration on cell proliferation. Furthermore, knockdown of IGHMBP2 increased the expression level of E-cadherin. In addition, Western blot was also used to detect the changes in the expression level of apoptosis related proteins PARP1 and Caspase3 after knocking down IGHMBP2 in KYSE30 and KYSE150 and not obvious change were found. Conclusion: IGHMBP2 overexpression may promotes the ability of invasion and migration of ESCC cell lines through down-regulating the expression of E-cadherin.