1.H19 recruited N 6 -methyladenosine (m 6 A) reader YTHDF1 to promote SCARB1 translation and facilitate angiogenesis in gastric cancer.
Rumeng BAI ; Miaomiao SUN ; Yuanyuan CHEN ; Shuaishuai ZHUO ; Guoxin SONG ; Tianjun WANG ; Zhihong ZHANG
Chinese Medical Journal 2023;136(14):1719-1731
BACKGROUND:
Angiogenesis is described as a complex process in which new microvessels sprout from endothelial cells of existing vasculature. This study aimed to determine whether long non-coding RNA (lncRNA) H19 induced the angiogenesis of gastric cancer (GC) and its possible mechanism.
METHODS:
Gene expression level was determined by quantitative real-time polymerase chain reaction and western blotting. Cell counting kit-8, transwell, 5-Ethynyl-2'-deoxyuridine (EdU), colony formation assay, and human umbilical vein endothelial cells (HUVECs) angiogenesis assay as well as Matrigel plug assay were conducted to study the proliferation, migration, and angiogenesis of GC in vitro and in vivo . The binding protein of H19 was found by RNA pull-down and RNA Immunoprecipitation (RIP). High-throughput sequencing was performed and next Gene Ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was conducted to analyze the genes that are under H19 regulation. Methylated RIP (me-RIP) assay was used to investigate the sites and abundance among target mRNA. The transcription factor acted as upstream of H19 was determined through chromatin immunoprecipitation (ChIP) and luciferase assay.
RESULTS:
In this study, we found that hypoxia-induced factor (HIF)-1α could bind to the promoter region of H19, leading to H19 overexpression. High expression of H19 was correlated with angiogenesis in GC, and H19 knocking down could inhibit cell proliferation, migration and angiogenesis. Mechanistically, the oncogenic role of H19 was achieved by binding with the N 6 -methyladenosine (m 6 A) reader YTH domain-containing family protein 1 (YTHDF1), which could recognize the m 6 A site on the 3'-untransated regions (3'-UTR) of scavenger receptor class B member 1 (SCARB1) mRNA, resulting in over-translation of SCARB1 and thus promoting the proliferation, migration, and angiogenesis of GC cells.
CONCLUSION
HIF-1α induced overexpression of H19 via binding with the promoter of H19, and H19 promoted GC cells proliferation, migration and angiogenesis through YTHDF1/SCARB1, which might be a beneficial target for antiangiogenic therapy for GC.
Humans
;
Cell Line, Tumor
;
Cell Proliferation/genetics*
;
Endothelial Cells/metabolism*
;
Gene Expression Regulation
;
Gene Expression Regulation, Neoplastic/genetics*
;
Hypoxia
;
MicroRNAs/genetics*
;
RNA
;
RNA, Long Noncoding/metabolism*
;
RNA-Binding Proteins/metabolism*
;
Scavenger Receptors, Class B/metabolism*
;
Stomach Neoplasms/genetics*
2.Effects of C10orf10 on growth and prognosis of glioma under hypoxia.
Yuanbing CHEN ; Miao TANG ; Hui LI ; Jun HUANG
Journal of Central South University(Medical Sciences) 2023;48(4):499-507
OBJECTIVES:
Glioma is the most common malignant tumor in the central nervous system, and the hypoxic microenvironment is prevalent in solid tumors. This study aims to investigate the up-regulation of genes under the condition of hypoxia and their roles in glioma growth, as well as their impact on glioma prognosis.
METHODS:
The hypoxia-related dataset with glioma was screened in the Gene Expression Omnibus database (GEO), and the differentially expressed genes were analyzed between hypoxia and normoxia through bioinformatics, and chromosome 10 open reading frame 10 (C10orf10) was verified and screened in hypoxia-treated cells through real-time PCR and Western blotting. The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) datasets were downloaded to analyze the mRNA expression of C10orf10 in different grades of glioma and its impact on prognosis. The glioma specimens and follow-up data of 68 gliomas who underwent surgical treatment in Xiangya Hospital of Central South University from March 2017 to January 2021 were collected, and real-time PCR was used to detect the mRNA expression of C10orf10 in different grades of glioma, and the Kaplan-Meier method was used to analyze the relationship between the expression C10orf10 and prognosis. The glioma cells, which could interfere the expression of C10orf10, were constructed, and the effect of C10orf10 on the proliferation of glioma cells was evaluated by cell counting kit-8 (CCK-8) and colony formation assays.
RESULTS:
Compared with the condition of normoxia, the expression levels of C10orf10 mRNA and protein were significantly up-regulated in glioma cells under hypoxia (P<0.001), and the mRNA expression level of C10orf10 in glioma tissues was up-regulated with the increase of WHO grade in glioma (P<0.001). Based on Kaplan-Meier survival analysis, the higher the mRNA expression level of C10orf10 was, the shorter the survival time of the patient was (P<0.05). And the expression of C10orf10 mRNA was higher in recurrent gliomas than that in primary gliomas in the CGGA database (P<0.001). Knockdown of C10orf10 could significantly inhibit the growth of glioma cells both under hypoxia and normoxia (both P<0.001).
CONCLUSIONS
The expression level of C10orf10 can promote the proliferation and prognosis of glioma, which is expected to become a prognostic marker and therapeutic target for glioma.
Humans
;
Central Nervous System
;
Glioma/genetics*
;
Hypoxia
;
Neoplasm Recurrence, Local
;
Prognosis
;
Tumor Microenvironment
3.Read-through circular RNA rt-circ-HS promotes hypoxia inducible factor 1α expression and renal carcinoma cell proliferation, migration and invasiveness.
Yun Yi XU ; Zheng Zheng SU ; Lin Mao ZHENG ; Meng Ni ZHANG ; Jun Ya TAN ; Ya Lan YANG ; Meng Xin ZHANG ; Miao XU ; Ni CHEN ; Xue Qin CHEN ; Qiao ZHOU
Journal of Peking University(Health Sciences) 2023;55(2):217-227
OBJECTIVE:
To identify and characterize read-through RNAs and read-through circular RNAs (rt-circ-HS) derived from transcriptional read-through hypoxia inducible factor 1α (HIF1α) and small nuclear RNA activating complex polypeptide 1 (SNAPC1) the two adjacent genes located on chromosome 14q23, in renal carcinoma cells and renal carcinoma tissues, and to study the effects of rt-circ-HS on biological behavior of renal carcinoma cells and on regulation of HIF1α.
METHODS:
Reverse transcription-polymerase chain reaction (RT-PCR) and Sanger sequencing were used to examine expression of read-through RNAs HIF1α-SNAPC1 and rt-circ-HS in different tumor cells. Tissue microarrays of 437 different types of renal cell carcinoma (RCC) were constructed, and chromogenic in situ hybridization (ISH) was used to investigate expression of rt-circ-HS in different RCC types. Small interference RNA (siRNA) and artificial overexpression plasmids were designed to examine the effects of rt-circ-HS on 786-O and A498 renal carcinoma cell proliferation, migration and invasiveness by cell counting kit 8 (CCK8), EdU incorporation and Transwell cell migration and invasion assays. RT-PCR and Western blot were used to exa-mine expression of HIF1α and SNAPC1 RNA and proteins after interference of rt-circ-HS with siRNA, respectively. The binding of rt-circ-HS with microRNA 539 (miR-539), and miR-539 with HIF1α 3' untranslated region (3' UTR), and the effects of these interactions were investigated by dual luciferase reporter gene assays.
RESULTS:
We discovered a novel 1 144 nt rt-circ-HS, which was derived from read-through RNA HIF1α-SNAPC1 and consisted of HIF1α exon 2-6 and SNAPC1 exon 2-4. Expression of rt-circ-HS was significantly upregulated in 786-O renal carcinoma cells. ISH showed that the overall positive expression rate of rt-circ-HS in RCC tissue samples was 67.5% (295/437), and the expression was different in different types of RCCs. Mechanistically, rt-circ-HS promoted renal carcinoma cell proliferation, migration and invasiveness by functioning as a competitive endogenous inhibitor of miR-539, which we found to be a potent post-transcriptional suppressor of HIF1α, thus promoting expression of HIF1α.
CONCLUSION
The novel rt-circ-HS is highly expressed in different types of RCCs and acts as a competitive endogenous inhibitor of miR-539 to promote expression of its parental gene HIF1α and thus the proliferation, migration and invasion of renal cancer cells.
Humans
;
Carcinoma, Renal Cell/pathology*
;
Cell Proliferation
;
Hypoxia
;
Kidney Neoplasms
;
MicroRNAs/genetics*
;
Neoplasm Invasiveness/genetics*
;
RNA, Circular/metabolism*
;
RNA, Small Interfering
;
Hypoxia-Inducible Factor 1, alpha Subunit/genetics*
4.LINC00926 promotes pyroptosis of hypoxia-induced human umbilical vein vascular endothelial cells by recruiting ELAVL1.
Yong JIANG ; Wenting GE ; Ying ZHAO ; Yuge WU ; Yiming HUO ; Lanting PAN ; Shuang CAO
Journal of Southern Medical University 2023;43(5):807-814
OBJECTIVE:
To investigate the regulatory role of the long non-coding RNA LINC00926 in pyroptosis of hypoxia-induced human umbilical vein vascular endothelial cells (HUVECs) and explore the molecular mechanism.
METHODS:
HUVECs were transfected with a LINC00926-overexpressing plasmid (OE-LINC00926), a siRNA targeting ELAVL1, or both, followed by exposure to hypoxia (5% O2) or normoxia. The expression of LINC00926 and ELAVL1 in hypoxia-treated HUVECs was detected using real-time quantitative PCR (RT-qPCR) and Western blotting. Cell proliferation was detected using Cell Counting Kit-8 (CCK-8), and the levels of IL-1β in the cell cultures was determined with ELISA. The protein expression levels of pyroptosis-related proteins (caspase-1, cleaved caspase-1 and NLRP3) in the treated cells were analyzed using Western blotting, and the binding between LINC00926 and ELAVL1 was verified with RNA immunoprecipitation (RIP) assay.
RESULTS:
Exposure to hypoxia obviously up-regulated the mRNA expression of LINC00926 and the protein expression of ELAVL1 in HUVECs, but did not affect the mRNA expression of ELAVL1. LINC00926 overexpression in the cells significantly inhibited cell proliferation, increased IL-1β level and enhanced the expressions of pyroptosis-related proteins (all P < 0.05). LINC00926 overexpression further up-regulated the protein expression of ELAVL1 in hypoxia-exposed HUVECs. The results of RIP assay confirmed the binding between LINC00926 and ELAVL1. ELAVL1 knockdown significantly decreased IL-1β level and the expressions of pyroptosis-related proteins in hypoxia-exposed HUVECs (P < 0.05), while LINC00926 overexpression partially reversed the effects of ELAVL1 knockdown.
CONCLUSION
LINC00926 promotes pyroptosis of hypoxia-induced HUVECs by recruiting ELAVL1.
Humans
;
Caspase 1
;
ELAV-Like Protein 1
;
Human Umbilical Vein Endothelial Cells
;
Pyroptosis
;
RNA, Messenger
;
RNA, Long Noncoding/genetics*
;
Cell Hypoxia
5.Research progress on the mechanism of phenotypic transformation of pulmonary artery smooth muscle cells induced by hypoxia.
Journal of Zhejiang University. Medical sciences 2023;51(6):750-757
Phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs) is a key factor in pulmonary vascular remodeling. Inhibiting or reversing phenotypic transformation can inhibit pulmonary vascular remodeling and control the progression of hypoxic pulmonary hypertension. Recent studies have shown that hypoxia causes intracellular peroxide metabolism to induce oxidative stress, induces multi-pathway signal transduction, including those related to autophagy, endoplasmic reticulum stress and mitochondrial dysfunction, and also induces non-coding RNA regulation of cell marker protein expression, resulting in PASMCs phenotypic transformation. This article reviews recent research progress on mechanisms of hypoxia-induced phenotypic transformation of PASMCs, which may be helpful for finding targets to inhibit phenotypic transformation and to improve pulmonary vascular remodeling diseases such as hypoxia-induced pulmonary hypertension.
Humans
;
Pulmonary Artery
;
Hypertension, Pulmonary
;
Vascular Remodeling/genetics*
;
Hypoxia/genetics*
;
Myocytes, Smooth Muscle
;
Cell Proliferation/physiology*
;
Cells, Cultured
;
Cell Hypoxia/genetics*
6.Targeting TRMT5 suppresses hepatocellular carcinoma progression via inhibiting the HIF-1α pathways.
Qiong ZHAO ; Luwen ZHANG ; Qiufen HE ; Hui CHANG ; Zhiqiang WANG ; Hongcui CAO ; Ying ZHOU ; Ruolang PAN ; Ye CHEN
Journal of Zhejiang University. Science. B 2023;24(1):50-63
Accumulating evidence has confirmed the links between transfer RNA (tRNA) modifications and tumor progression. The present study is the first to explore the role of tRNA methyltransferase 5 (TRMT5), which catalyzes the m1G37 modification of mitochondrial tRNAs in hepatocellular carcinoma (HCC) progression. Here, based on bioinformatics and clinical analyses, we identified that TRMT5 expression was upregulated in HCC, which correlated with poor prognosis. Silencing TRMT5 attenuated HCC proliferation and metastasis both in vivo and in vitro, which may be partially explained by declined extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Mechanistically, we discovered that knockdown of TRMT5 inactivated the hypoxia-inducible factor-1 (HIF-1) signaling pathway by preventing HIF-1α stability through the enhancement of cellular oxygen content. Moreover, our data indicated that inhibition of TRMT5 sensitized HCC to doxorubicin by adjusting HIF-1α. In conclusion, our study revealed that targeting TRMT5 could inhibit HCC progression and increase the susceptibility of tumor cells to chemotherapy drugs. Thus, TRMT5 might be a carcinogenesis candidate gene that could serve as a potential target for HCC therapy.
Humans
;
Carcinoma, Hepatocellular/pathology*
;
Cell Hypoxia
;
Cell Line, Tumor
;
Gene Expression Regulation, Neoplastic
;
Hypoxia-Inducible Factor 1, alpha Subunit/metabolism*
;
Liver Neoplasms/pathology*
;
Signal Transduction/genetics*
;
tRNA Methyltransferases/metabolism*
7.Physical exercise suppresses hepatocellular carcinoma progression by alleviating hypoxia and attenuating cancer stemness through the Akt/GSK-3β/β-catenin pathway.
Chu-Lan XIAO ; Zhi-Peng ZHONG ; Can LÜ ; Bing-Jie GUO ; Jiao-Jiao CHEN ; Tong ZHAO ; Zi-Fei YIN ; Bai LI
Journal of Integrative Medicine 2023;21(2):184-193
OBJECTIVE:
Physical exercise, a common non-drug intervention, is an important strategy in cancer treatment, including hepatocellular carcinoma (HCC). However, the mechanism remains largely unknown. Due to the importance of hypoxia and cancer stemness in the development of HCC, the present study investigated whether the anti-HCC effect of physical exercise is related to its suppression on hypoxia and cancer stemness.
METHODS:
A physical exercise intervention of swimming (30 min/d, 5 d/week, for 4 weeks) was administered to BALB/c nude mice bearing subcutaneous human HCC tumor. The anti-HCC effect of swimming was assessed in vivo by tumor weight monitoring, hematoxylin and eosin (HE) staining, and immunohistochemistry (IHC) detection of proliferating cell nuclear antigen (PCNA) and Ki67. The expression of stemness transcription factors, including Nanog homeobox (NANOG), octamer-binding transcription factor 4 (OCT-4), v-Myc avian myelocytomatosis viral oncogene homolog (C-MYC) and hypoxia-inducible factor-1α (HIF-1α), was detected using real-time reverse transcription polymerase chain reaction. A hypoxia probe was used to explore the intratumoral hypoxia status. Western blot was used to detect the expression of HIF-1α and proteins related to protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β)/β-catenin signaling pathway. The IHC analysis of platelet endothelial cell adhesion molecule-1 (CD31), and the immunofluorescence co-location of CD31 and desmin were used to analyze tumor blood perfusion. SMMC-7721 cells were treated with nude mice serum. The inhibition effect on cancer stemness in vitro was detected using suspension sphere experiments and the expression of stemness transcription factors. The hypoxia status was inferred by measuring the protein and mRNA levels of HIF-1α. Further, the expression of proteins related to Akt/GSK-3β/β-catenin signaling pathway was detected.
RESULTS:
Swimming significantly reduced the body weight and tumor weight in nude mice bearing HCC tumor. HE staining and IHC results showed a lower necrotic area ratio as well as fewer PCNA or Ki67 positive cells in mice receiving the swimming intervention. Swimming potently alleviated the intratumoral hypoxia, attenuated the cancer stemness, and inhibited the Akt/GSK-3β/β-catenin signaling pathway. Additionally, the desmin+/CD31+ ratio, rather than the number of CD31+ vessels, was significantly increased in swimming-treated mice. In vitro experiments showed that treating cells with the serum from the swimming intervention mice significantly reduced the formation of SMMC-7721 cell suspension sphere, as well as the mRNA expression level of stemness transcription factors. Consistent with the in vivo results, HIF-1α and Akt/GSK-3β/β-catenin signaling pathway were also inhibited in cells treated with serum from swimming group.
CONCLUSION
Swimming alleviated hypoxia and attenuated cancer stemness in HCC, through suppression of the Akt/GSK-3β/β-catenin signaling pathway. The alleviation of intratumoral hypoxia was related to the increase in blood perfusion in the tumor. Please cite this article as: Xiao CL, Zhong ZP, Lü C, Guo BJ, Chen JJ, Zhao T, Yin ZF, Li B. Physical exercise suppresses hepatocellular carcinoma progression by alleviating hypoxia and attenuating cancer stemness through the Akt/GSK-3β/β-catenin pathway. J Integr Med. 2023; 21(2): 184-193.
Humans
;
Animals
;
Mice
;
Carcinoma, Hepatocellular/drug therapy*
;
Proto-Oncogene Proteins c-akt/metabolism*
;
Proliferating Cell Nuclear Antigen/therapeutic use*
;
Mice, Nude
;
Glycogen Synthase Kinase 3 beta/genetics*
;
beta Catenin/therapeutic use*
;
Liver Neoplasms/drug therapy*
;
Desmin/therapeutic use*
;
Ki-67 Antigen
;
Cell Line, Tumor
;
Hypoxia
;
RNA, Messenger/therapeutic use*
;
Cell Proliferation
8.Shenfu Injection alleviates sepsis-associated lung injury by regulating HIF-1α.
Luan-Luan ZHANG ; Ya-Nan ZI ; Ye-Peng ZHANG ; Hui PEI ; Xiang-Yu ZHENG ; Jia-Feng XIE ; Dong XU ; Zhi-Qiang ZHU
China Journal of Chinese Materia Medica 2023;48(23):6492-6499
Shenfu Injection(SFI) is praised for the high efficacy in the treatment of septic shock. However, the precise role of SFI in the treatment of sepsis-associated lung injury is not fully understood. This study investigated the protective effect of SFI on sepsis-associated lung injury by a clinical trial and an animal experiment focusing on the hypoxia-inducing factor-1α(HIF-1α)-mediated mitochondrial autophagy. For the clinical trial, 70 patients with sepsis-associated lung injury treated in the emergency intensive care unit of the First Affiliated Hospital of Zhengzhou University were included. The levels of interleukin(IL)-6 and tumor necrosis factor(TNF)-α were measured on days 1 and 5 for every patient. Real-time quantitative polymerase chain reaction(RT-qPCR) was performed to determine the mRNA level of hypoxia inducible factor-1α(HIF-1α) in the peripheral blood mononuclear cells(PBMCs). For the animal experiment, 32 SPF-grade male C57BL/6J mice(5-6 weeks old) were randomized into 4 groups: sham group(n=6), SFI+sham group(n=10), SFI+cecal ligation and puncture(CLP) group(n=10), and CLP group(n=6). The body weight, body temperature, wet/dry weight(W/D) ratio of the lung tissue, and the pathological injury score of the lung tissue were recorded for each mouse. RT-qPCR and Western blot were conducted to determine the expression of HIF-1α, mitochondrial DNA(mt-DNA), and autophagy-related proteins in the lung tissue. The results of the clinical trial revealed that the SFI group had lowered levels of inflammatory markers in the blood and alveolar lavage fluid and elevated level of HIF-1α in the PBMCs. The mice in the SFI group showed recovered body temperature and body weight. lowered TNF-α level in the serum, and decreased W/D ratio of the lung tissue. SFI reduced the inflammatory exudation and improved the alveolar integrity in the lung tissue. Moreover, SFI down-regulated the mtDNA expression and up-regulated the protein levels of mitochondrial transcription factor A(mt-TFA), cytochrome c oxidase Ⅳ(COXⅣ), HIF-1α, and autophagy-related proteins in the lung tissue of the model mice. The findings confirmed that SFI could promote mitophagy to improve mitochondrial function by regulating the expression of HIF-1α.
Humans
;
Male
;
Mice
;
Animals
;
Leukocytes, Mononuclear
;
Mice, Inbred C57BL
;
Lung/metabolism*
;
Acute Lung Injury/drug therapy*
;
Tumor Necrosis Factor-alpha/genetics*
;
Sepsis/genetics*
;
Hypoxia/pathology*
;
Autophagy-Related Proteins
;
Body Weight
;
Drugs, Chinese Herbal
9.Salidroside improves intestinal mucosal immune status of rats under compound stress of hypoxia and training via inhibiting TLR4/NF-κB signaling pathway.
Qin XU ; Hongyan PENG ; Yongmei ZHAO ; Tuolihanayi TUOLIKEN ; Wendong BAI
Chinese Journal of Cellular and Molecular Immunology 2023;39(9):801-806
Objective To investigate the effect of salidroside on intestinal mucosal immune status in rats under compound stress of hypoxia and training (HTCS) and the mechanism. Methods SD rats were randomly divided into HTCS model group (model), placebo group (placebo) and salidroside group (salidro). Model group received no intervention, and placebo and salidro group received intraperitoneal injection of normal saline and salidroside, respectively. Then, ileum tissue of rats were collected and the intestinal damage was assayed by HE staining and Chiu scores. Intestinal permeability indices, including serum D-diamine oxidase (DAO), D-lactic acid (DLA) and endotoxin (END) and secretory immunoglobulin A (sIgA) of intestinal tissue were detected by ELISA. T lymphocyte subsets of intestinal tissue were detected by flow cytometry. Expression of tight junction molecules, including ZO-1, Claudin-3, occluding, were detected by PCR and western blot. Activation of TLR4/NF-κB signaling pathway was detected by Western blot analysis. Results Compared with model group and placebo group, salidro group had the decreased intestinal mucosal injury and low Chiu score, and the level of intestinal permeability indices including serum DAO, DLA and END fell off. CD4+ T cell percentage, CD4+/CD8+ ratio and sIgA level were went up, while CD8+ T cell percentage was went down. mRNA and the level of protein expressions of ZO-1, claudin-3 and occludin increased, while activation of TLR4/NF-κB signaling pathway was inhibited. Conclusion Salidroside can alleviate the intestinal barrier injury and improve intestinal mucosal immune status of rats under compound stress of hypoxia and training via inhibiting TLR4/NF-κB signalling pathway.
Animals
;
Rats
;
Rats, Sprague-Dawley
;
NF-kappa B
;
Toll-Like Receptor 4/genetics*
;
Claudin-3
;
Hypoxia
;
Immunoglobulin A, Secretory
;
Signal Transduction
10.Activation of HIF-1α/ACLY signaling axis promotes progression of clear cell renal cell carcinoma with VHL inactivation mutation.
Y MA ; Y H WANG ; S HUANG ; Z G ZOU ; L HU ; L C GUO
Chinese Journal of Pathology 2023;52(12):1230-1236
Objective: To explore the potential pathogenesis of clear cell renal cell carcinoma (ccRCC) based on the HIF-1α/ACLY signaling pathway, as well as to provide new ideas for the treatment of ccRCC. Methods: Seventy-eight ccRCC cases diagnosed at the First Affiliated Hospital of Soochow University, Suzhou, China were collected. The VHL mutation was examined using exon sequencing. The expression of HIF-1α/ACLY in VHL-mutated ccRCC was evaluated using immunohistochemical staining and further validated in VHL-mutated ccRCC cell lines (786-O, A498, UM-RC-2, SNU-333, and Caki-2) using Western blot. The mRNA and protein levels of ACLY were detected using real-time quantitative PCR and Western blot after overexpression or interference with HIF-1α in ccRCC cell lines. HeLa cells were treated with CoCl2 and hypoxia (1%O2) to activate HIF-1α and then subject to the detection of the ACLY mRNA and protein levels. The potential molecular mechanism of HIF-1α-induced ACLY activation was explored through JASPAR database combined with chromatin immunoprecipitation assay (ChIP) and luciferase reporter gene assay. The effect of HIF-1α/ACLY regulation axis on lipid accumulation was detected using BODIPY staining and other cell biological techniques. The expression of ACLY was compared between patients with ccRCC and those with benign lesions, and the feasibility of ACLY as a prognostic indicator for ccRCC was explored through survival analysis. Results: Exon sequencing revealed that 55 (70.5%) of the 78 ccRCC patients harbored a VHL inactivation mutation, and HIF-1α expression was associated with ACLY protein levels. The protein levels of ACLY and HIF-1α in ccRCC cell lines carrying VHL mutation were also correlated to various degrees. Overexpression of HIF-1α in A498 cells increased the mRNA and protein levels of ACLY, and knockdown of HIF-1α in Caki-2 cells inhibited the mRNA and protein levels of ACLY (P<0.001 for all). CoCl2 and hypoxia treatment significantly increased the mRNA and protein levels of ACLY by activating HIF-1α (P<0.001 for all). The quantification of transcriptional activity of luciferase reporter gene and ChIP-qPCR results suggested that HIF-1α could directly bind to ACLY promoter region to transcriptionally activate ACLY expression and increase ACLY protein level (P<0.001 for all). The results of BODIPY staining suggested that the content of free fatty acids in cell lines was associated with the levels of HIF-1α and ACLY. The depletion of HIF-1α could effectively reduce the accumulation of lipid in cells, while the overexpression of ACLY could reverse this process. At the same time, cell function experiments showed that the proliferation rate of ccRCC cells with HIF-1α knockdown was significantly decreased, and overexpression of ACLY could restore proliferation of these tumor cells (P<0.001). Survival analysis further showed that compared with the ccRCC patients with low ACLY expression, the ccRCC patients with high ACLY expression had a poorer prognosis and a shorter median survival (P<0.001). Conclusions: VHL mutation-mediated HIF-1α overexpression in ccRCC promotes lipid synthesis and tumor progression by activating ACLY. Targeting the HIF-1α/ACLY signaling axis may provide a theoretical basis for the clinical diagnosis and treatment of ccRCC.
Humans
;
Carcinoma, Renal Cell/pathology*
;
Kidney Neoplasms/pathology*
;
HeLa Cells
;
Von Hippel-Lindau Tumor Suppressor Protein/genetics*
;
Mutation
;
Signal Transduction
;
Luciferases/therapeutic use*
;
Hypoxia/genetics*
;
RNA, Messenger
;
Lipids/therapeutic use*
;
Hypoxia-Inducible Factor 1, alpha Subunit/genetics*
;
Cell Line, Tumor
;
Gene Expression Regulation, Neoplastic

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