Inhibitory effect of ARHI on pancreatic cancer cells and NF-κB activity

Abstract

The aim of this study was to investigate the effect of aplasia ras homolog member I (ARHI) on proliferation, apoptosis and the cell cycle in the pancreatic cancer cell line PANC-1. The study also aimed to examine the effect of ARHI on the activity of the nuclear factor (NF)-κB and to determine whether ARHI acts as a tumor suppressor in the development of pancreatic cancer by inhibiting the activity of NF-κB. A pIRES2‑EGFP‑ARHI vector, constructed by reverse transcrition (RT)‑PCR, was transiently transfected into the PANC-1 cells and analyzed for the expression of the ARHI protein by western blotting. A MTT assay was used to quantify cell proliferation, and apoptosis was analyzed by flow cytometry. The NF‑κB signaling pathway, specifically the pathway using the nuclear phosphorylated p65 isoform, was analyzed by western blotting. Expression of the ARHI protein was detected by western blotting subsequent to the PANC-1 cells being transiently transfected with the pIRES2‑EGFP‑ARHI construct. Cell proliferation was strongly inhibited in the PANC-1 cells transfected with pIRES2‑EGFP‑ARHI. The cell cycle assays indicated an increase in the number of cells at the G0/G1 phase and a decrease in the cells at the S phase, but the difference was not significant (P>0.05). Time course studies also indicated a marked increase in the apoptotic index following transient transfection, as well as a gradual decrease in the expression of the nuclear phosphorylated p65 protein. ARHI acts as a tumor suppressor by downregulating the NF‑κB signaling pathway, which results in the inhibition of cell proliferation, apoptosis and the cell cycle in the pancreatic tumor PANC-1 cell line.

SERP1 is a novel marker of poor prognosis in pancreatic ductal adenocarcinoma patients via anti-apoptosis and regulating SRPRB/NF-κB axis

“…Activation of NF-κB mainly occurs via phosphorylation of NF-κB proteins, such as p65, within their transactivation domain by a variety of kinases in response to distinct stimuli, and then enhanced cell anti-apoptosis ability ( 37 ). In fact, phosphorylated p65 was significantly upregulated in PDAC cell lines, and associated with cell proliferation, cell cycle, and apoptosis ( 38 ). Moreover, specific targeted inhibition the phosphorylation NF-κB pathways could induce cell apoptosis ( 39 ).…”

ARHI (DIRAS3) induces autophagy in ovarian cancer cells by downregulating the epidermal growth factor receptor, inhibiting PI3K and Ras/MAP signaling and activating the FOXo3a-mediated induction of Rab7

“…36 In addition to ovarian cancer, downregulation of ARHI has been associated with cancers at other sites, including breast, prostate, pancreatic, thyroid and lung carcinomas. 4,[37][38][39][40][41][42][43][44][45][46] Consequently, the observations made in ovarian cancer are likely to be relevant to many other types of cancer. In the future, it will be of interest to explore the interaction of ARHI and FOXo3a across cancers that originate from non-ovarian sites.…”

Breast cancer cells are arrested at different phases of the cell cycle following the re-expression of ARHI

“…Structural differences also support the observation that ARHI remains the only tumor suppressor gene identified in the Ras superfamily to date (18). Characterization of ARHI activity has included the following observations; in a study by Hu et al (19), ARHI was shown to mediate downregulation of the NF-κB signaling pathway, thereby acting as a tumor suppressor protein in pancreatic cancer cells. Low expression levels of ARHI were also associated with a shorter progressionfree survival period for pancreatic cancer patients (20).…”