title: Increased expression of protease-activated receptor 4 and Trefoil factor 2 in human colorectal cancer.
abstract: Protease-activated receptor 4 (PAR4), a member of G-protein coupled receptors family, was recently reported to exhibit decreased expression in gastric cancer and esophageal squamous cancer, yet increased expression during the progression of prostate cancer. Trefoil factor 2 (TFF2), a small peptide constitutively expressed in the gastric mucosa, plays a protective role in restitution of gastric mucosa. Altered TFF2 expression was also related to the development of gastrointestinal cancer. TFF2 has been verified to promote cell migration via PAR4, but the roles of PAR4 and TFF2 in the progress of colorectal cancer are still unknown. In this study, the expression level of PAR4 and TFF2 in colorectal cancer tissues was measured using real-time PCR (n = 38), western blotting (n=38) and tissue microarrays (n = 66). The mRNA and protein expression levels of PAR4 and TFF2 were remarkably increased in colorectal cancer compared with matched noncancerous tissues, especially in positive lymph node and poorly differentiated cancers. The colorectal carcinoma cell LoVo showed an increased response to TFF2 as assessed by cell invasion upon PAR4 expression. However, after intervention of PAR4 expression, PAR4 positive colorectal carcinoma cell HT-29 was less responsive to TFF2 in cell invasion. Genomic bisulfite sequencing showed the hypomethylation of PAR4 promoter in colorectal cancer tissues and the hypermethylation in the normal mucosa that suggested the low methylation of promoter was correlated to the increased PAR4 expression. Taken together, the results demonstrated that the up-regulated expression of PAR4 and TFF2 frequently occurs in colorectal cancer tissues, and that overexpression of PAR4 may be resulted from promoter hypomethylation. While TFF2 promotes invasion activity of LoVo cells overexpressing PAR4, and this effect was significantly decreased when PAR4 was knockdowned in HT-29 cells. Our findings will be helpful in further investigations into the functions and molecular mechanisms of Proteinase-activated receptors (PARs) and Trefoil factor factors (TFFs) during the progression of colorectal cancer.
authors: Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China; Department of Biochemistry, Kunming Medical University, Kunming, Yunnan 650500, China.
authors: Guoyu
authors: G
authors: Yu
authors: Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China; Department of Pathology and Pathophysiology, Kunming Medical University, Kunming, Yunnan 650500, China.
authors: Ping
authors: P
authors: Jiang
authors: Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors: Yang
authors: Y
authors: Xiang
authors: Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors: Yong
authors: Y
authors: Zhang
authors: Department of Gastroenterology, the First Affiliated Hospital of Kunming Medical University, Kunming 650032, China.
authors: Zhu
authors: Z
authors: Zhu
authors: Department of Functional Experimental Center, Kunming Medical University, Kunming, Yunnan 650500, China.
authors: Chuanrao
authors: C
authors: Zhang
authors: Department of Biochemistry, Kunming Medical University, Kunming, Yunnan 650500, China.
authors: Siman
authors: S
authors: Lee
authors: Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors: Wenhui
authors: W
authors: Lee
authors: Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors: Yun
authors: Y
authors: Zhang
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000737:chemistry; D001374:Azacitidine / Q000031:analogs & derivatives / Q000737:chemistry; D045744:Cell Line, Tumor; D002465:Cell Movement; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D000077209:Decitabine; D018450:Disease Progression; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D046228:Microarray Analysis; D009361:Neoplasm Invasiveness; D010455:Peptides / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D018179:Receptors, Thrombin / Q000378:metabolism*; D000071164:Trefoil Factor-2
chemical_list: D000964:Antimetabolites, Antineoplastic; D010455:Peptides; D018179:Receptors, Thrombin; C000604007:TFF2 protein, human; D000071164:Trefoil Factor-2; D000077209:Decitabine; C112908:protease-activated receptor 4; D001374:Azacitidine