The Role Of CREB3Gene In Metastasis Of Colorectal Cancer And Its Mechanism

Background:Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide. Metastases are the most common cause of death in CRC patients. There are currently no tests or biomarkers that precisely predict the ability of invasion and metastasis. It is clear that improvements in detection of invasion and metastasis are required. Identifying biomarkers that can monitor CRC invasion, metastasis would enable personalization of medicine and improve survival rates of patients with cancer. CREB3(Luman or LZIP), the prototype of this subfamily, is a bZIP transcription factor. It is not only involved in ER (Endoplasmic Reticulum) stress and UPR(Unfolded Protein Response), but also plays a crucial role in many other biological processes including cell secretion, cell migration as well as oncogenesis.CREB3was reported to interact with transcriptional coactivator HCF1, hepatitis C virus core protein, CC chemokine receptor1and dendritic cell specific transmembrane protein. CREB3was also reported to be influential in the metastasis of breast cancer cells and cervical cancer cells.This research intends to study the biomarkers associated with metastasis of colorectal cancer and improve the clinic detection of metastaic CRC.Methods:(1) The differentially expressed spectral of mRNAs in colorectal cancer FFPE tissues were detected by mRNA microarray.(2) The results of mRNA microarray were verified by using in situ hybridization and immunohistochemical techniques.(3)The expression of CREB3in colorectal cancer cell lines (HCT116, SW480and SW620) was detected by QPCR.(4) The invasive ability of colorectal cancer cell lines was detected by transwell migration assay;(5) CREB3’s localization in SW480cell was detected by immunocytochemistry.(6) The expression of TWIST1, β-catenin, MMP9and MMP2in colorectal cancer cell lines was detected by QPCR.(7)(after) Interfering CREB3in SW480cell line by the use of siRNA, the expression of TWIST1, β-catenin, MMP9and MMP2was detected by QPCR.Results:(1) mRNA microarray result showed that, expression of CREB3were significantly upregulated in both metastases vs primary tumors and recurrence vs primary tumors.(2) In situ hybridization and immunohistochemistry results showed that the expression of CREB3in metastasis vs non-metastasis primary tumors and adjacent tissues was significantly up-regulated.(3) QPCR results showed that the expression of CREB3in SW480cells was the highest.(4) SW480cells have the strongest capacity of migration.(5) In SW480cells, CREB3mains located in the cytoplasm with little expression in the nucleus.(6) Like CREB3, the expressions of β-catenin, MMP9and MMP2were highest in SW480cells.(7) After interfering SW480cells with CREB3siRNA, QPCR results showed a significant decrease in the expression of MMP2; no obvious change in the expression of Twist1, β-catenin and MMP9.Conclusions:The expression of CREB3may be associated with metastasis of colorectal cancer and CREB3may promote metastasis of CRC through manipulating MMP2.