JWA IS REQUIRED FOR THE ANTIPROLIFERATIVE AND PRO‐APOPTOTIC EFFECTS OF ALL‐TRANS RETINOIC ACID IN HELA CELLS

Abstract

1. All-trans retinoic acid (ATRA) is known to inhibit cellular proliferation and induce differentiation and apoptosis. It usually activates gene expression by binding to a nuclear receptor that interacts with retinoic acid-response elements (RARE) and then activates the mitogen-activated protein kinase signal pathway. JWA, a newly identified ATRA-responsive gene, has recently been proposed as an important molecule for cellular differentiation induced by some chemicals, including ATRA. 2. To investigate the possible involvement of JWA in the inhibition of cellular proliferation and induction of apoptosis by ATRA, HeLa cells were stably transfected with sense or antisense JWA to establish cell lines that overexpressed or were deficient in JWA; ATRA (0.05-10 micromol/L) was used to induce cellular differentiation and apoptosis. 3. Western blot analysis revealed that ATRA caused increased expression of JWA in HeLa cells in a dose- and time-dependent manner, accompanied by activation of extracellular signal-regulated kinase (ERK) 1/2 phosphorylation. However, ERK1/2 phosphorylation induced by ATRA was inhibited in JWA-deficient HeLa cells. In JWA-overexpressing HeLa cells, ATRA showed more significant antiproliferative effects and induced more apoptosis. 4. The reporter gene assay showed that ATRA (5 mmol/L) enhanced the transcriptional activity of JWA by interacting with its promoter in the region from -194 to +107 bp (P < 0.01). Bioinformatic analysis indicated that the JWA promoter did not contain RARE, but did contain two CCAAT boxes in this fragment spanning -194 to +107 bp, which may be responsive to the ATRA-activated nuclear transcription factor CCAAT/enhancer binding proteins (C/EBP) or interacting proteins. Therefore, ATRA-inhibited cellular proliferation and -induced apoptosis in HeLa cells may be dependent on JWA transactivation via its C/EBP-binding motifs. 5. These data indicate that the inhibition of proliferation and the induction of apoptosis by ATRA are dependent on JWA expression in HeLa cells. The findings may represent a novel mechanism by which the effects of ATRA in regulating cellular proliferation and apoptosis are mediated, at least in part, by JWA expression.

Regulation of apoptotic and growth inhibitory activities of C/EBPα in different cell lines

“…In addition to our analyses, a paper by Mao et al has shown that all-trans retinoic acid inhibits proliferation and causes apoptosis through the activation of ARL6IP5 and that this activation is mediated by C/EBPα through direct binding to the promoter of ARL6IP5 [21]. Therefore, we suggested that the ARL6IP5 gene might be a key protein which mediates pro-apoptotic activity of C/EBPα in NIH3T3 cells and have investigated the role of ARL6IP5 in proapoptotic activity of C/EBPα.…”

“…This target is the ARL6IP5 protein which has been previously characterized as an inducer of apoptosis in cultured cells. The promoter region of the ARL6IP5 gene contains two binding sites for C/EBP proteins and potentially might be regulated by C/EBP proteins [21]. Given the ubiquitous expression of another member of C/EBP family, C/EBPβ, one would assume that the ARL6IP5 promoter might be active in many cell types.…”

Expression of Prenylated Rab Acceptor 1 Domain Family, Member 2 (PRAF2) in Neuroblastoma: Correlation with Clinical Features, Cellular Localization, and Cerulenin-Mediated Apoptosis Regulation

“…The PRAF2-related protein PRAF3 (JWA/GTRAP3-18) was recently implicated in the regulation of retinoic acid-induced cell differentiation, cell migration, and apoptosis in various cancer types, including leukemia and cervical cancer (23)(24)(25)(26)(27). These findings prompted us to examine whether PRAF2 plays a role in neuroblastoma apoptosis.…”

Application of Arsenic Trioxide Therapy for Patients with Leukaemia

“…JWA, a novel signaling molecule, has been reported to be associated with cell differentiation, growth inhibition, and apoptosis induction mediated by ATO, ATRA, and 12-Otetradecanoylphorbol 13-acetate in human malignant cells including myeloid leukaemia cell lines and primary cultured APL blasts [112][113][114]. Recently, Zhou et al reported that JWA is required for ATO induced apoptosis in HeLa and MCF-7 cells via ROS and mitochondria linked signal pathways [115].…”