Involvement of endoplasmic reticulum stress in adenosine-induced human hepatoma HepG2 cell apoptosis

Abstract

Abstract. endoplasmic reticulum stress (ers)-mediated cell apoptosis has been implicated in the development of multiple diseases such as cancer, neurodegenerative diseases and ischemic reperfusion damage. previous studies have demonstrated the adenosine-induced apoptosis in several tumor cell lines. However, the role of ers in adenosine-induced human hepatoma Hepg2 cell apoptosis remains unclear. the present study was designed to determine whether ers is involved in adenosine-induced Hepg2 cell apoptosis. the Mtt assay was used to determine proliferation, and DApI staining of cell nuclei was performed to determine cell apoptosis. the translocation of cHop and caspase-3 was observed by immunofluorescence analysis, and the protein expression of CHOP, caspase-4 and caspase-3 was detected by Western blotting. the Mtt assay demonstrated that adenosine inhibited Hepg2 cell proliferation in a dose-dependent manner. DApI staining of cell nuclei and cell cycle analysis verified cell apoptosis. The immunofluorescence assay demonstrated that adenosine induced the translocation of cHop and of caspase-3 from the cytoplasm to the nucleus. Western blotting confirmed that cHop, caspase-4 and caspase-3 were up-regulated in Hepg2 cells after treatment with adenosine. However, JnK protein expression was not altered. These results show that ERS is involved in the adenosine-induced Hepg2 cell apoptosis.

Enhanced Antitumor Effects of Adenoviral-Mediated siRNA against GRP78 Gene on Adenosine-Induced Apoptosis in Human Hepatoma HepG2 Cells

“…In our previous study, adenosine induces ER stress and NF-κB activation [7,9,26]. In this study, we show that adenosine up-regulates the expressions of Bak and Bax and causes cell accumulation in the G0/G1 phase and apoptosis (Figures 2 and 7).…”

“…In the present study, we show a recombinant RNAi adenoviral vector (Ad-shGRP78) encoding a GFP78-targeting shRNA, decreases GFP78 mRNA levels to 24.5% and 19.3% at 100 and 200 MOI in 293A cells (Figure 1A). Our previous studies show adenosine induces HepG2 and EC109 cell apoptosis by ER stress and upregulates GRP78 expression [7,9]. Because GRP78 protects tumor cells and endows them with increased chemoresistance, downregulation of GRP78 may become an important adjunct in future anti-tumor therapy.…”

“…To obtain further evidence for apoptosis, DNA fragmentation was also determined using a TdT-mediated dUTP-FITC nick-end labeling (TUNEL) assay as described previously [7,9]. Cells were fixed by immersing slides in freshly prepared 4% methanol-free formaldehyde solution in PBS for 20 min at room temperature and permeabilized with 0.2% Triton X-100 for 5 min.…”

“…Adenosine, a ubiquitous metabolite from ATP hydrolysis, induces apoptosis in a variety of cancer cells and is a chemotherapy drug with wide prospect of clinical application [5–8]. In our previous studies, adenosine induces apoptosis in EC 109 and HepG2 cells by the ER stress pathway [7,9]. However, the potential roles of ER stress-related genes in the cytotoxic effects of adenosine are unclear.…”

The mechanism of adenosine-mediated activation of lncRNA MEG3 and its antitumor effects in human hepatoma cells

“…Adenosine and their analogues can interfere with the synthesis of nucleic acids and exert genotoxic activity by incorporating with and altering the DNA or RNA macromolecules, which makes them exciting candidates for anticancer therapy (12)(13)(14). Although MEG3 plays a role in inhibiting tumor growth, no data are available on its function under genotoxic stress-induced apoptosis.…”