Int. J. Biol. Sci. 2021, Vol. 17 1782 Ivyspring International Publisher International Journal of Biological Sciences 2021; 17(7): 1782-1794. doi: 10.7150/ijbs.59068 Research Paper Aldolase A Enhances Intrahepatic Cholangiocarcinoma Proliferation and Invasion through Promoting Glycolysis Xiang Li1,2*, Chang Yu2*, Yichun Luo2*, Jiacheng Lin2, Fang Wang2, Xuehua Sun2, Yueqiu Gao2, Weifeng Tan1, Qiang Xia1, Xiaoni Kong2 1. Department of Hepatic Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. 2. Central Laboratory, Department of Liver Diseases, ShuGuang Hospital Affiliated to Shanghai University of Chinese Traditional Medicine, Shanghai, China. * These authors contributed equally to this work. Corresponding authors: Xiaoni Kong, PhD, Central Laboratory, Department of Liver Diseases, ShuGuang Hospital Affiliated to Shanghai University of Chinese Traditional Medicine,528 Zhangheng Road, Shanghai, China, 201203. Telephone: +86 21 20256838. E-mail: [email protected]; Or Qiang Xia, MD, PhD, E-mail: [email protected]; Or Weifeng Tan, MD, PhD, E-mail: [email protected]. © The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). See http://ivyspring.com/terms for full terms and conditions. Received: 2021.02.05; Accepted: 2021.04.05; Published: 2021.04.23 Abstract Energy metabolism reprogramming has been implicated in tumorigenesis and development. Key metabolism enzyme Aldolase A (ALDOA) has been shown to be highly expressed and involved in various kinds of cancers including hepatocellular carcinoma. In this study, we found that ALDOA was highly expressed in clinical intrahepatic cholangiocarcinoma (ICC) tissues, and its high expression was negatively correlated with overall survival (OS) and recurrence-free survival (RFS) in ICC patients. Knockdown of ALDOA expression significantly inhibited the proliferation and migration of ICC both in vitro and in vivo, while highly-expressed ALDOA in ICC cells promoted the proliferation and migration of ICC cells. By applying ALDOA inhibitor and metabolic mass spectrometry tests, we demonstrated that ALDOA modulated the biological characteristics and metabolic level of ICC cells depending on its enzymatic activity. In summary, ALDOA promotes ICC proliferation and migration by enhancing ICC cells glycolysis. Blocking enzymatic activity of ALDOA provides a strategy to inhibit ICC. Key words: Intrahepatic Cholangiocarcinoma, Aldolase A, Metabolism Reprogram, Enzymatic Activity, Glycolysis. Introduction Primary liver cancer is one of the most common many studies on the pathogenesis of intrahepatic malignancies of the digestive system. According to its cholangiocarcinoma, but no clear pathogenesis or pathological type, primary liver cancer can be divided effective treatment has been proposed. into hepatocellular carcinoma (HCC) and intrahepatic Having an abnormal metabolic level is one of the cholangiocarcinoma (ICC) [1]. ICC is a kind of main characteristics of tumor cells [4, 5]. As early as in malignant tumor that arises from the epithelial cells of the 1920s, Otto Warburg proposed that malignant segmental or proximal branches of the bile duct. The tumors mainly generate energy through glycolysis incidence rate of ICC accounts for 15% of all primary even in the presence of oxygen recombination rather liver malignancies, and it is the second most common than tricarboxylic acid cycling or oxidative liver cancer after HCC [2]. Although the incidence of phosphorylation. This phenomenon is also known as ICC is less than HCC, the degree of malignancy is the Warburg effect [6]. Currently, metabolic higher, the treatment tolerance is higher, and the abnormality, chiefly the Warburg effect, is thought to prognosis is poorer [3]. Therefore, ICC is a difficult play an important role in oncogenesis and tumor clinical problem that needs to be solved. There are progression in a variety of tumors [7]. Many glycolytic http://www.ijbs.com Int. J. Biol. Sci. 2021, Vol. 17 1783 enzymes such as PKM2 and HK have been proved to that were approved by the ethical review committee influence tumor progression by participating in the of the World Health Organization’s Collaborating regulation of tumor signal transduction [8], acting as a Center for Research in Human Production phospho-tyrosine-binding protein [9], or influencing (authorized by Shanghai Municipal Government). protein-protein interaction (PPI) of tumor cells as a The cholangiocarcinoma cell line RBE, HuCCT1 and coactivator [10]. FRH-0201 were purchased from the Cell Bank of the Aldolase A (ALDOA) is a member of the Chinese Academy of Sciences (Shanghai, China). aldolase family, mainly involved in the glycolysis pathway, catalyzing the reversible conversion of Cell culture β-D-fructose-1,6-bisphosphate to D-glyceraldehyde The ICC cell lines were cultured in RPMI 1640 3-phosphate and dihydroxyacetone phosphate [11]. medium (Gibco, C11875500CP) plus 10% (v/v) FBS Although the function of ALDOA in tumor (Gibco, 10099141C) plus Penicillin 100 U/mL and progression has been intensively studied, the role and Streptomycin 100μg/mL (Gibco, 15140122) at 37°C mechanism of ALDOA in liver cancer, especially in and 5% CO2. ICC, has not been studied yet. Through statistical RNA extraction, cDNA synthesis and qPCR analysis of clinical TCGA and GEO databases, we found that in liver tumors (including HCC and ICC Total RNA was extracted by total RNA rapid samples), the expression level of ALDOA was extraction kit (Bioteke Corporation, RP4002). A total significantly higher than that of adjacent cancer or of 500 ng RNA was reverse-transcribed using HiScript normal liver, and the expression of ALDOA was II Q RT SuperMix for the qPCR kit (Vazyme, R222-01). significantly and negatively related to the poor The cDNA was diluted (1:10) for qPCR using ChamQ prognosis of patients (Supplementary Figure 1), SYBR qPCR Master Mix (Vazyme, Q311-02) with suggesting that ALDOA might play an important gene-specific primers. Results were normalized by function in liver cancer. β-actin control. The primer sequences are as follows: In this study, we validated the expression levels ALDOA-Forward: 5’-GCTGTCACTGGGATCACC of ALDOA in clinical ICC samples and revealed a TTC-3’, ALDOA-Reverse: 5’-GCTCGGAGTGTA significant correlation between ALDOA expression CTTTCCTTGA-3’; β-actin Forward: 5’-ctccatcctggc and the survival rates of patients. Knockdown of ctcgctgt-3’, β-actin Reverse: 5’-gctgtcaccttcaccgttcc-3’. ALDOA significantly inhibited the proliferation and Protein extraction and Western blot migration of ICC cells, while exogenously-induced Cells or tumor tissues were lysed on ice with overexpression of ALDOA enhanced the proliferation RIPA (Thermo Scientific, 89900) containing protease of tumor cells. By using an inhibitor (Itaconate) to inhibitor (MCE, HY-K0010) for 30 mins. After repress the enzymatic activity of ALDOA, we found centrifugation for 10 mins at 12000 rpm, the that the tumor proliferation and invasion were supernatants were transferred to new EP tubes. The suppressed, suggesting that ALDOA promotes ICC protein samples were quantified by the BCA method. cell proliferation through its enzymatic activity. Then samples were denatured at 100 ℃ for 10 mins. Further, by testing the glycolytic function with Protein extracts were resolved on 12% SDS-PAGE seahorse and detecting downstream metabolites of gels, transferred to nitrocellulose membranes (0.45 the glycolysis pathway by mass spectrometry, we mm) after electrophoresis, and immunoblotted with found that the knockdown of ALDOA expression in special primary antibodies. Images were developed tumor cells leads to a lower level of glycolytic with ECL (GE Health Care, USA). The ALDOA products compared to that of control cells. All these antibody (11217-1-AP) was purchased from findings may help to better understand the Proteintech. The β-actin antibody with HRP (A3854) pathogenesis of ICC and provide a new target for ICC and the anti-flag M2 antibody (F1804) were purchased treatment. from Sigma. Materials and methods Tissue microarrays and immunohistochemical Clinical specimens and cell lines staining The human tumor and paired para-tumor tissues The ICC tissue microarrays contain 52 matched and ICC specimens of the validation cohort were pairs of specimens. Strict pathological diagnoses and obtained from ICC patients undergoing hepatectomy post-operative follow-ups were performed for all at Renji Hospital affiliated to Shanghai Jiaotong patients. IHC staining was performed to detect the University School of Medicine. Patient samples were expression of ALDOA. Sections were scored as obtained following informed consent and protocols positive if tumor cells showed a staining reaction in the cytoplasm and/or the nucleus. A quantitative http://www.ijbs.com Int. J. Biol. Sci. 2021, Vol. 17 1784 score was given by estimating the percentages of reagents were added and cells were incubated at 37°C positive cells: 0, (0–5%); 1, (5%–25%); 2, (25%–50%); 3, for 2 hrs before being measured at the wavelength of (50%–75%); and 4, (75%–100%). The intensity of 450 nm by the microplate reader. All experiments positive staining was given scores as negative (0), were performed independently at least 3 times. pallide-flavens grains (1), buffy grains (2), and brown-black grains (3) respectively. Finally, total Wound healing assay scores (0–7) for each sample were determined by the Cells were cultured in 6-well