PLCD1 Suppressed Cellular Proliferation, Invasion, and Migration via Inhibition of Wnt/ß-Catenin Signaling Pathway in Esophageal Squamous Cell Carcinoma.

BACKGROUND: Phospholipase C delta 1 (PLCD1) has been found to be abnormally expressed in various cancers. However, the potential roles of PLCD1 in esophageal squamous cell carcinoma (ESCC) are still unknown. METHODS: Western blot and qPCR were used to explore PLCD1 expression in various ESCC cells. MTT, colony formation assays, wound-healing assay, and transwell cell invasion assay were used to examine the cell viability in vitro. Western blot, qPCR, and luciferase assays were used to investigate the effects of PLCD1 on Wnt/ß-catenin signaling pathway. The xenograft models in nude mice were established to explore the roles of PLCD1 in vivo. RESULTS: We found that the expression of PLCD1 in ESCC cells was significantly downregulated than that in normal esophageal epithelial cells. In addition, upregulation of PLCD1 decreased the capacity of TE-1 and EC18 cells in proliferation, invasion, and migration. Then, the expression of ß-catenin/p-ß-catenin, C-myc, cyclin D1, MMP9, and MMP7 was investigated. PLCD1 activity was found to be negatively associated with the expression of ß-catenin, C-myc, cyclin D1, MMP9, and MMP7. Finally, the activity of PLCD1 in inhibiting ESCC proliferation in vivo was validated. CONCLUSION: The inhibitory effects of PLCD1 on the proliferation, invasion, and migration of TE-1 and EC18 cells might be associated with inhibition of Wnt/ß-catenin signaling pathway. PLCD1 played a key role in inhibiting ESCC carcinogenesis and progression in patients with ESCC.

MicroRNA-497 accelerates apoptosis while inhibiting proliferation, migration, and invasion through negative regulation of the MAPK/ERK signaling pathway via RAF-1.

The aim of this study is to explore the various modes of action miR-497 has on human cervical cancer (CC) cell behavior. We also speculate that miR-497 achieves its anti-tumor role by governing RAF-1 via MAPK/ERK signaling pathway. CC tissues with corresponding adjacent normal tissues were collected from 168 CC patients. RAF-1-positive cells were identified by means of immunohistochemistry in tissues. A series of inhibitors, mimics and siRNA against RAF-1 were introduced to validate regulatory mechanisms for miR-497 and RAF-1. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assay were employed for evaluating alternations of miR-497, RAF-1, and MAPK/ERK signaling pathway. HeLa cell proliferation, invasion, migration, cycle progression, and apoptosis were assessed by means of CCK-8, wound-healing, transwell invasion assays, and flow cytometry, respectively. The target prediction program and luciferase activity determination were used to identify miR-497 targeting RAF-1. We determined reduced miR-497 expression and elevated expression of RAF-1 in CC tissues as opposed to adjacent tissues. Transfection of miR-497 mimics and siRNA-RAF-1 both decreased levels of MEK1, ERK1, and p38 phosphorylation in HeLa cells, inhibited cell proliferation, migration and invasion, induced more cells arrested in the G0/G1 phase, and promoted cell apoptosis; while miR-497 inhibitors led to opposite results. These findings indicate miR-497 as a tumor suppressor results from negative regulation of the MAPK/ERK signaling pathway via RAF-1 in CC.