PYCR1 interference inhibits cell growth and survival via c-Jun N-terminal kinase/insulin receptor substrate 1 (JNK/IRS1) pathway in hepatocellular cancer

Juhua Zhuang,Jiening Wang,Ying Ye,Yanan Song,Jing Ni,Wei Xia,Saifei He,Miao Zhang,Xing Ma

doi:10.1186/s12967-019-2091-0

Abstract

BackgroundLiver cancer is the second leading causes of cancer-related death globally. Pyrroline-5-carboxylate reductase 1 (PYCR1) plays a critical role in metabolic profiles of tumors. Therefore, it is necessary to explore the mechanisms of PYCR1 on cell growth and survival in hepatocellular carcinoma (HCC).MethodsProtein and mRNA expression levels of PYCR1 in 140 pairs of tumor and adjacent normal liver tissues of HCC patients were analyzed by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR). Expressions of PYCR1 were inhibited in BEL-7404 cells and SMMC-7721 cells using gene interference technology. The cell proliferation was detected by Celigo and MTT assay. The colony formation assay was also performed. The cell apoptosis was measured by flow cytometric assay. The effect of PYCR1 interference on tumor growth was observed by xenograft nude mice assay in vivo. The downstream pathway of PYCR1 interference was searched by microarray and bioinformatics analysis, and validated by qRT-PCR and western blot.ResultsPYCR1 levels were significantly up-regulated in HCC tumor tissues than adjacent normal liver tissues in both protein and mRNA levels (P < 0.01). In vitro, the cell proliferation was significantly slower in shPYCR1 group than shCtrl group in BEL-7404 and SMMC-7721 cells (P < 0.001). The colony number was significantly smaller after PYCR1 interference (P < 0.01). The percentage of apoptosis cells significantly increased in shPYCR1 group (P < 0.01). In vivo, PYCR1 interference could obviously suppress tumor growth in xenograft nude mice. The volume and weight of tumors were significantly smaller via PYCR1 interference. The c-Jun N-terminal kinase (JNK) signaling pathway significantly altered, and insulin receptor substrate 1 (IRS1) were significantly down-regulated by PYCR1 interference in both mRNA and protein levels (P < 0.001).ConclusionPYCR1 interference could inhibit cell proliferation and promote cell apoptosis in HCC through regluting JNK/IRS1 pathway. Our study will provide a drug target for HCC therapy and a potential biomarker for its diagnosis or prognosis.

Highlights

Liver cancer is the second leading causes of cancer-related death globally
Pyrroline-5-carboxylate reductase 1 (PYCR1) was over expressed in hepatocellular carcinoma (HCC) tumor tissues To find out whether PYCR1 was dysregulated in HCC patients, we determined PYCR1 protein expression levels in tumor and adjacent normal liver tissues of HCC patients by IHC
Our data revealed that PYCR1 levels were higher expressed in tumor tissues than adjacent normal ones (Fig. 1a), and IHC scores were statistically (See figure on page.) Fig. 2 The cell proliferation and cell apoptosis influenced by PYCR1 interference in BEL-7404 and SMMC-7721 cells. a, b shPYCR1 group suppressed PYCR1 expression in both mRNA and protein levels

Summary

Introduction

Pyrroline-5-carboxylate reductase 1 (PYCR1) plays a critical role in metabolic profiles of tumors. It is necessary to explore the mechanisms of PYCR1 on cell growth and survival in hepatocellular carcinoma (HCC). A better understanding of the key molecules and regulative pathways involved in the etiology and progression of HCC may lead to improved treatments. Growing tumors alter their metabolic profiles to meet the biosynthetic and bioenergetics demands of increased cell growth and proliferation [6]. Proline plays key roles in many aspects, such as cellular signaling processes [11], cellular bioenergetics [12], and cancer cell metabolism [13]. The role of PYCR1 in HCC cell growth and survival is still unclear

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