Raf kinase inhibitor protein inhibits esophageal cancer cell invasion through downregulation of matrix metalloproteinase expression

Abstract

Esophageal cancer is the eighth most common malignant tumor in the world and is a common cause of tumor-related death. The development of esophageal cancer is a complex process involving many pathogenetic factors, multiple stages and accumulation of multiple gene mutations and interactions. This study aimed to investigate the effects of Raf kinase inhibitor protein (RKIP) on the proliferation, apoptosis and invasion of TE-1 esophageal cancer cells. Surgical specimens from esophageal cancer patients were classified into esophageal cancer tissues, tumor-adjacent tissues and normal esophageal tissues. The tissues were fixed in 4% paraformaldehyde solution for hematoxylin and eosin and immunohistochemical staining. RKIP expression in esophageal tissues was detected by immunohistochemical staining. The esophageal cancer cell line TE-1 was exposed to four different viruses: RKIP-RNAi-AD, NC-RNAi-GFP-AD, RKIP-AD and GFP-AD. Cell proliferation was detected by MTT assay and cell apoptosis was detected by flow cytometry. Cell invasion was determined by a Transwell coated with Matrigel. RKIP, phospho-RKIP, Raf-1, phospho-Raf-1, ERK1/2, phospho-ERK1/2, GRK-2 and GAPDH expression was assayed by western blotting. LIN28 and MMP-14 mRNA was assayed by qPCR. The results showed that RKIP expression was reduced in esophageal cancer tissues in comparison with expression in normal esophageal epithelium tissues and tumor-adjacent tissues. Reduced RKIP expression was associated with lymph node or distant metastasis in esophageal cancer. RKIP inhibited the invasive and metastatic abilities of esophageal cancer cell line TE-1 by downregulating mRNA expression of LIN28 and MMP-14. RKIP had no effect on the MAPK signaling pathway in the esophageal cancer cell line TE-1, but was involved in the G protein-coupled signaling pathway. Our findings clearly demonstrate that RKIP inhibits esophageal cancer cell invasion by downregulating the expression of GRK-2, LIN28 and MMP-14.

Raf kinase inhibitor protein inhibits cholangiocarcinoma cell metastasis by downregulating matrix metalloproteinase 9 and upregulating tissue inhibitor of metalloproteinase 4 expression

“…The sections were stained and the RKIP staining results were scored by a previously described method ( 14 , 15 ). Tissues with a final score that exceeded the median score were classed as having high RKIP expression and tissues with a final score equal to or below the median exhibited downregulated RKIP expression.…”

“…The total RNA from the RBE cells was isolated using TRIzol reagent (Tiangen Biotech (Beijing) Co., Ltd., Beijing, China), according to the manufacturer’s instructions ( 14 ). Overall, ~200 ng of total RNA was converted to first-strand cDNA using a SuperScript-II RT system (Life Technologies, Carlsbad, CA, USA).…”

“…We have also previously demonstrated an association between lymph node or distant metastasis in decreased RKIP expression and esophageal cancer tissues. The study demonstrated that RKIP downregulates the expression of GRK-2, Lin28 and matrix metalloproteinase (MMP)-14 ( 14 ). However, the association between RKIP expression and the progression of cholangiocarcinoma, and the effect of its regulation on the biological behavior of cholangiocarcinoma cells is not yet clear.…”

RKIP: A Key Regulator in Tumor Metastasis Initiation and Resistance to Apoptosis: Therapeutic Targeting and Impact

“…In many cancers, the expression of MMPs such as -1, -3, -10, and -13 is negatively correlated with RKIP levels, suggesting that RKIP may constrain metastasis through inhibition of MMPs [147]. Interestingly, it has been proposed that the expression signature of RKIP and MMPs is better at predicting high metastatic risks in various cancers than the individual protein [102].…”

A novel long non-coding RNA lnc-GNAT1-1 is low expressed in colorectal cancer and acts as a tumor suppressor through regulating RKIP-NF-κB-Snail circuit

“…In this study, a significant positive expression correlation between lnc-GNAT1-1 and RKIP was detected. RKIP has been reported to be a tumor suppressors in a variety of cancer types, including colorectal cancer [9, 10, 24], gastric cancer [25, 26], esophageal cancer [27], breast cancer [28], etc., and the mechanisms were mainly attributed to its involvement in the RKIP -NF-κB-Snail circuit in previous reports [13, 29, 30]. In this study, we found a positive correlation between expression of lnc-GNAT1-1 and RKIP, both in cells level and in patients’ tissues.…”