DLC-1 induces mitochondrial apoptosis and epithelial mesenchymal transition arrest in nasopharyngeal carcinoma by targeting EGFR/Akt/NF-κB pathway

Abstract

Loss of deleted in liver cancer-1 (DLC-1) can induce apoptosis and inhibit the mobility, migration and metastasis in several cancers. Previously, we revealed that ectopic expression of DLC-1 can suppress proliferation, mobility, migration and tumorigenesis in nasopharyngeal carcinoma (NPC). However, the molecular mechanisms accounting for the roles of DLC-1 in NPC are still obscure. In the present work, we attempted to study and uncover the mechanisms underlying the functions of DLC-1 in NPC. The apoptosis of 5-8F-DLC-1 cells, established previously, was analyzed by mitochondrial membrane potentials assay and flow cytometer analysis. And the antibodies involving pathways such as mitochondrial-associated apoptosis, epithelial mesenchymal transition and metastasis were applied to detect and compare the expression level of targeted proteins. The obvious apoptosis of 5-8F-DLC-1 cells was observed reflected by mitochondrial depolarization and lower ratio in cell viability. Subsequently, the activation of mitochondrial apoptosis was verified by the increased expressions of Bax, Apaf1, cleave-caspases and cleave-PARP, etc, and the decreased expressions of Bcl-2, Bcl-xL, Mcl-1, Survivin, etc, in 5-8F-DLC-1 cells. Then, the inhibited epithelial mesenchymal transition of 5-8F-DLC-1 cells was validated by upregulated expression of E-cadherin and downregulated expression of N-cadherin, Snail, Vimentin. Subsequently, downregulated expressions of proteins such as FAK, RhoA, ROCK1 and cdc25 related to cell adhesion and cytoskeleton organization were also observed. And expressions of MMPs were inhibited in 5-8F-DLC-1 cells. At last, the inhibited activity of EGFR/Akt/NF-κB axis was revealed by the decreased expressions of phosho-EGFR, phosho-Akt, phosho-p38MAPK, phosho-IKKα and phosho-p65. Here, we systematically explored the mechanisms underlying the negative roles of DLC-1 in NPC cells. For the first time, we confirmed that the ectopic expression DLC-1 can induce mitochondrial apoptosis, inhibit EMT and related processes by targeting the EGFR/Akt/NF-κB pathway, which, beyond all doubt, offered beneficial guidelines for other studies and laid a good foundation for its clinical applications ultimately.

IL-17A promotes the proliferation of human nasopharyngeal carcinoma cells through p300-mediated Akt1 acetylation

“…Since Akt1 activation is considered to be involved in human NPC cell proliferation (14–17), the effect of IL-17A stimulation on Akt1 activation was further investigated in NPC cells. It was demonstrated that the levels of Akt1 phosphorylation at Thr 308 and Ser 473 sites were markedly enhanced in C666-1 cells stimulated by IL-17A for 30 min in vitro compared with the untreated control group (Fig.…”

“…Among these, AKT serine/threonine kinase 1 (Akt1) activation has been revealed to serve an essential role in numerous types of carcinoma, including NPC (14–21). Thus, targeting aberrant Akt1 signaling may provide an effective and novel strategy for the treatment of patients with NPC.…”

CD109 is identified as a potential nasopharyngeal carcinoma biomarker using aptamer selected by cell-SELEX

“…Western blot was done in accordance with our manual [43]. In brief, cells were lysed by RIPA and total proteins were obtained.…”

A tumor suppressor DLC1: The functions and signal pathways

“…The restoration of DLC1 expression by DLC1 cDNA or GFP‐siFAK‐DLC1 vector transfection results in caspase3‐mediated apoptosis, and inhibits proliferation and invasiveness in Burkitt's lymphoma, renal cell carcinoma, prostate carcinoma, liver cancer, HT29, OVCAR‐3, NPC and gallblader cancer cells, as well as reduces the ability of tumor formation in athymic nude mice (Qin et al, ; Shi, Liu, & Zhao, ). Ectopic expression of DLC1 can also induce mitochondrial apoptosis, as well as inhibit epithelial–mesenchymal transition and its related processes through targeting the EGFR/Akt/NF‐κB pathway in NPC (Huang et al, ). In addition, different localizations of DLC1 have different functions.…”