FOXD1 Promotes CRC Cell Growth And Metastasis Via The ERK1/2 Signaling Pathway

Background and aims:Colorectal cancer(CRC)is one of the most common malignant tumors worldwide,and its incidence is increasing every year in most countries.However,the underlying molecular mechanisms still is largely unknown.Moreover,it remains difficult to predict early CRC using existing biomarkers.Therefore,achieving a better understanding of the mechanism will be helpful in detecting specific and sensitive biomarkers to predict early CRC.Forkhead Box D1(FOXD1)is a member of Forkhead box(Fox).Accumulating evidences has suggested that FOXD1 may play an essential role in the carcinogenesis and progression of human cancers.The aberrant expression of FOXD1 in breast cancer,ovarian cancer and glioma has received extensive attention from oncologists.However,the role of FOXD1 in CRC has not been explored.Consequently,the aim of our study is to explore the expression pattern of FOXD1 in CRC patients and its biological functions in CRC cell.Methods:We first collected the tissue samples from CRC patients.The expression pattern of FOXD1 in human CRC tissues and corresponding normal tissues was examined by qRT-PCR and IHC staining.After that,the correlation between the expression pattern of FOXD1 and its clinicopathological features in CRC was analyzed statistically.The biological effect of FOXD1 on CRC cells were investigated by stable clones.CCK-8 assay was used to detect cell proliferation;Plate clonogenicity assays was examined by plate clonogenicity;Transwell assays was applied to investigate cell migration and invasion;and Western blotting analysis was employ to detect the effects of FOXD1 on ERK1/2 signaling pathways.ERK1/2 signaling pathway inhibitor(U0126)was used to confirm the ability of FOXD1 to promote the proliferation and metastasis of CRC cells through ERK1/2 signaling pathway.Results:Compared with the corresponding normal tissues,the expression of FOXD1 was significantly increased in CRC tissues and was also high in most colorectal cancer cell lines.Further analysis of clinicopathological features from 126 CRC patients revealed that FOXD1 expression was correlated with tumor size(P = 0.025),tissue differentiation(P = 0.036),depth of invasion(P = 0.01),TNM stage(P = 0.023),lymph nodal metastasis(P = 0.021),and poor prognosis(P = 0.0158).Whereas,there was no statistical correlation between the expression of FOXD1 and other clinicopathological features such as age(P = 0.284),gender(P = 0.800)and distance metastasis(P = 0.447)were not related.Through the construction of stable transfected cell lines,biological experiments showed that FOXD1 overexpression could promote the proliferation,cloning,migration and invasion of colorectal cancer cells and down-regulation of FOXD1 could inhibit the above functions.In addition,FOXD1 could affect the phosphorylation of ERK1/2 in colorectal cancer cells.Overexpression of FOXD1 increased the phosphorylation level,and knocked down the phosphorylation level.ERK1/2 inhibitor(U0126)can reverse cell proliferation and metastasis induced by overexpression of FOXD1.Conclusions:FOXD1 expression increased in CRC tissues and most CRC cells.Overexpression of FOXD1 in CRC tissue is significantly correlated with tumor size,tissue differentiation,depth of invasion,TNM stage,lymph nodal metastasis and poor survival of CRC patients.In addition,FOXD1 gene may act as an oncogene in CRC,affecting the proliferation,migration and invasion of colorectal cancer cells.These functions may be achieved by regulating the ERK1/2 signaling pathway.In conclusion,FOXD1 may be a potential target for gastric cancer treatment.