Up-Regulation of Glioma-Associated Oncogene Homolog 1 Expression by Serum Starvation Promotes Cell Survival in ER-Positive Breast Cancer Cells

Background/Aims: Zinc finger protein 703 (ZNF703), initially identified as a novel oncogene in human breast cancer, is a member of the NET/NlZ family of zinc finger transcription factors. It is recognized that the overexpression of ZNF703 is associated with various types of human cancers, but the role and molecular mechanism of ZNF703 in oral squamous cell carcinoma (OSCC) are unknown. Methods: ZNF703 expression levels were examined in OSCC tissues and non-cancerous tissues by qRT-PCR and immunohistochemistry (IHC). The molecular mechanisms of ZNF703 and its effects on cell growth and metastasis were explored in vitro and in vivo using the CCK8 assay, colony formation assay, cell cycle analysis, migration and invasion assays, wound-healing assay, western blotting and xenograft experiments in nude mice. Results: In this study, ZNF703 was found to be upregulated in OSCC tissues compared to that in normal tissues at both mRNA and protein levels, and its expression level was closely correlated with the overall survival of patients with OSCC. Silencing of the ZNF703 gene in OSCC cells significantly inhibited cell growth and metastasis in vitro and in vivo. Conversely, the overexpression of ZNF703 in OSCC cells promoted cancer growth and metastasis in vitro. Mechanistically, ZNF703 activated the PI3K/AKT/GSK-3β signalling pathway and its downstream effectors, thus regulating the cell cycle and epithelial-mesenchymal transition (EMT). Furthermore, the promotive effects of ZNF703 on cellular proliferation and metastasis could be rescued by LY294002 (a PI3K-specific inhibitor) and MK2206 (an Akt-specific inhibitor). Conclusion: The results show that ZNF703 promotes cell growth and metastasis through PI3K/Akt/GSK-3β signalling in OSCC and that it may be a promising target in the treatment of patients with OSCC.

Section: Discussionmentioning

confidence: 54%

Elevated Expression of Zinc Finger Protein 703 Promotes Cell Proliferation and Metastasis through PI3K/AKT/GSK-3β Signalling in Oral Squamous Cell Carcinoma

Wang

Deng

Zhang

et al. 2017

“…These cells both originated from pleural effusions and belong to subtypes of metastatic lobular carcinoma [2]. In principal, the MCF-7 cell line serves as a model of ER+ breast cancers because it expresses oestrogen receptor (ER), making these cells sensitive to oestrogen [3, 4], whereas the MDA-MB-231 cell line neither expresses hormone receptors nor human epidermal growth factor receptor-2 (HER-2), thus this cell line is used as a model of triple negative breast cancer (TNBC) [2]. In addition, there are other differences between these two cell lines.…”

Section: Introductionmentioning

confidence: 99%

Differential Expression Profiles of the Transcriptome in Breast Cancer Cell Lines Revealed by Next Generation Sequencing

Shi

Peng

Long³

2017

Background/Aims: As MCF-7 and MDA-MB-231 cells are the typical cell lines of two clinical breast tumour subtypes, the aim of the present study was to elucidate the transcriptome differences between MCF-7 and MDA-MB-231 breast cancer cell lines. Methods: The mRNA, miRNA (MicroRNA) and lncRNA (Long non-coding RNA) expression profiles were examined using NGS (next generation sequencing) instrument Illumina HiSeq-2500. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses were performed to identify the biological functions of differentially expressed coding RNAs. Subsequently, we constructed an mRNA-ncRNA (non-coding RNA) targeting regulatory network. Finally, we performed RT-qPCR (real-time quantitative PCR) to confirm the NGS results. Results: There are sharp distinctions of the coding and non-coding RNA profiles between MCF-7 and MDA-MB-231 cell lines. Among the mRNAs and ncRNAs with the most differential expression, SLPI, SOD2, miR-7, miR-143 and miR-145 were highly expressed in MCF-7 cells, while CD55, KRT17, miR-21, miR-10b, miR-9, NEAT1 and PICSAR were over-expressed in MDA-MB-231 cells. Differentially expressed mRNAs are primarily involved in biological processes of locomotion, biological adhesion, ECM-receptor interaction pathway and focal adhesion. In the targeting regulatory network of differentially expressed RNAs, mRNAs and miRNAs are primarily associated with tumour metastasis, but the functions of lncRNAs remain uncharacterized. Conclusion: These results provide a basis for future studies of breast cancer metastasis and drug resistance.

“…Serum provided a broad spectrum of nutrients for cell growth [37]. The data showed that both Si1 and serum starvation could significantly induce the number of autophagosome and the expression of LC3-II and Becin1.…”

Section: Discussionmentioning

confidence: 99%

Effect of the Serum Inhibited Gene (Si1) on Autophagy and Apoptosis in MCF-7 Breast Cancer Cells

Cui

Wang

et al. 2017

Background/Aims: The serum inhibited gene (Si1) was named according to its inhibited expression in response to serum exposure. Si1 has an important relationship with tumors. Autophagy and apoptosis are two types of cell death. However, there are few studies regarding the association between Si1 and autophagy, or apoptosis in tumors. In this, we investigated the effect of Si1 on the proliferation and cell cycle progression of MCF-7 cells and its influence on autophagy and apoptosis in MCF-7 cells. Methods: To investigate these functions of Si1 in tumor cells, we firstly constructed a pEGFP-Si1 overexpression vector and a pSilencer-Si1 interference vector, and we subsequently tested the proliferation and cell cycle progression of MCF-7 cells using the MTT assay and flow cytometry, and we then detected autophagy by western blotting and MDC (Monodansylcadaverine) staining as well as apoptosis by western blotting and Hoechst 33258 staining. Results: We found that the Si1 gene can significantly inhibit the viability of MCF-7 cells and arrest the cell cycle at the G2/M phase. Si1 can induce autophagy through upregulation of LC3-II and Beclin1, it can induce apoptosis through cleavage of PARP in MCF-7 cells. Conclusion: Altogether, our study indicated that Si1 can inhibit cell proliferation of MCF-7, and also induces autophagy and apoptosis. This study firstly investigated the effect of Si1 on autophagy and apoptosis in MCF-7 cells. Moreover, it also improves the current understanding of the mechanisms related to the effect of Si1 on tumor cells and also provides a foundation for gene-targeted therapy.