Protease-activated receptors (PARs) are a family of four G protein-coupled receptors that are expressed extensively in many cell types in the human body (e.g., neurons, immune cells, myocytes, platelets, fibroblasts, epithelial cells and endothelial cells). PARs regulate the expression of 2.9% of known human proteins and 1.3% of human genome, and the activation/deactivation of downstream signaling cascades triggered by PARs range from coagulation cascade, inflammation, pain transmission, and repair processes [
1]. The presence of PAR1, 2, and 4 promote cell proliferation and migration or apoptosis of types of cancer cells. PAR1 is primarily a thrombin receptor and has been shown to present in human colon cells but not in human colonic epithelial cells breast carcinoma cells, prostate cancer cells, colorectal cancer cells, ovarian cancer cells. Furthermore, the expression of PAR1 is involved in the promotion of tumor cell proliferation and migration. PAR1 and PAR2 both contribute to melanoma cell migration [
2]. Also, PAR2 has been proposed to contribute to breast cancer development [
3,
4], and cell proliferation and migration in colon cancer [
5]. At the same time, PAR4 functions as a suppressor in most tumor cells. The up-regulation of PAR4 induces apoptosis in prostate cancer cells [
6], and decreased expression of PAR4 resulted in aggressive gastric cancer [
7], breast cancer recurrence and poor prognosis [
8,
9], and the promotion of colon cancer cells [
10].
Esophageal cancer has become the 4th most common clinical diagnosed cancer and one of the top three leading causes of cancer-related deaths in China [
11]. Although the ratio of esophageal cancer only between one-third and one-half in total esophageal cancer, but the overall 5-year survival of esophageal carcinoma ranges from 15 to 25% [
12,
13]. The rates of esophageal carcinoma in rural areas were about twice the rate in urban areas. And the low fruit and vegetable intake and unhealthy lifestyle still was the popular cause of esophageal carcinoma genesis. The early prognosis would take a better chance of surviving 5 years after diagnosis. But the prognosis for esophageal carcinoma is poorly dismal in China, and the relative survival rates are about 20% [
11]. We hope the research would provide an efficient prognosis target for the esophageal cancer prognosis.
In this study, we aimed to clarify the differences in the expression of PAR1, 2, and 4 between human esophageal epithelial cells and clinical esophageal carcinoma tumor cells. Also, we show the relationships between the regulated expression of PARs (1, 2, and 4) and proliferation and apoptosis in the esophageal carcinoma cell line TE-1. Furthermore, the relationship between the methylation of CpG islands and the expression of PARs need more research. We examined changes of esophageal carcinoma cells growing ability based on the differential expressions of PAR1, 2, and 4 in vivo.