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Effects of insulin-like growth factor binding protein 3 on apoptosis of cutaneous squamous cell carcinoma cells

Authors Liu J, Guo Y, Huang Y, Xue H, Bai S, Zhu J, Xia X, Shen B, Fang W

Received 4 March 2018

Accepted for publication 27 July 2018

Published 5 October 2018 Volume 2018:11 Pages 6569—6577


Checked for plagiarism Yes

Review by Single-blind

Peer reviewer comments 3

Editor who approved publication: Dr Carlos E Vigil

Jinli Liu,1,* Yuanyuan Guo,2,* Yuanyuna Huang,3 Haowei Xue,4 Suwen Bai,2 Jinhang Zhu,2 Xianming Xia,3 Bing Shen,2 Wei Fang5

1Department of Dermatology, Anhui Provincial Hospital, Hefei 230001, Anhui, China; 2School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, China; 3Department of Gastroenterology and Hepatology, The Fourth Affiliated Hospital of Anhui Medical University, Hefei 230032, Anhui, China; 4Department of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui, China; 5Department of ICU, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266071, China

*These authors contributed equally to this work

Background: Cutaneous squamous cell carcinoma (CSCC) is the second most common carcinoma worldwide. Clinical treatment for patients with CSCC remains non-ideal. Insulin-like growth factor binding protein 3 (IGFBP3), a member of the insulin-like growth (IGF) system, participates in several biological processes, including cellular proliferation and apoptosis. Here, we explored the functional role of IGFBP3 in apoptosis and proliferation of A431 cells, a human CSCC cell line.
Materials and methods: Differential expression analysis, immunohistochemistry, immunoblotting, TUNEL assay, and CCK8 assay techniques were used to investigate the IGFBP3 expression levels in both A431 cells and CSCC tissue surgically obtained from humans as well as to explore the functional role of IGFBP3 in the apoptosis and proliferation of A431 cells.
Results: By using normal epidermal keratinocytes for comparison, we identified the top 10 ranked differentially upregulated genes expressed in human cutaneous squamous cell carcinoma cell lines. Among these 10 genes, IGFBP3 was ranked number 1. By using immunohistochemistry, we found that the expression level of IGFBP3 was significantly elevated in CSCC tissue compared with that in normal human skin tissue. Knockdown of IGFBP3 in A431 cells by transfection with IGFBP3-specific siRNA markedly altered the expression of proteins that contribute to apoptosis via mitochondrial pathways, significantly suppressing the expression of Bax and active caspase-3, while significantly increasing B-cell lymphoma-2 expression. TUNEL assay confirmed the effect of knockdown of IGFBP3 on the apoptosis as well. In addition, knockdown of IGFBP3 inhibited the proliferation of A431 cells.
Conclusion: IGFBP3 is overexpressed in both CSCC cell lines and tissue. Knockdown of IGFBP3 enhanced the apoptosis via a mitochondrial pathway and inhibited the proliferation of A431 cells. These findings indicate that IGFBP3 may be a biomarker and a potential therapeutic target for CSCC.

Keywords: CSCC, IGFBP3, proliferation, mitochondria

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