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*

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*

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

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*

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*

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

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

OBJECTIVES: Fluorouracil chemotherapeutic drugs are the classic treatment drugs of gastric cancer. But the problem of drug resistance severely limits their clinical application. This study aims to investigate whether hypoxia microenvironment affects gastric cancer resistance to 5-fluorouracil (5-FU) and discuss the changes of gene and proteins directly related to drug resistance under hypoxia condition. METHODS: Gastric cancer cells were treated with 5-FU in hypoxia/normoxic environment, and were divided into a Normoxic+5-FU group and a Hypoxia+5-FU group. The apoptosis assay was conducted by flow cytometry Annexin V/PI double staining. The real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to detect the expression level of hypoxia inducible factor-1α (HIF-1α), multidrug resistance (MDR1) gene, P-glycoprotein (P-gp), and vascular endothelial growth factor (VEGF) which were related to 5-FU drug-resistance. We analyzed the effect of hypoxia on the treatment of gastric cancer with 5-FU. RESULTS: Compared with the Normoxic+5-FU group, the apoptosis of gastric cancer cells treated with 5-FU in the Hypoxia+5-FU group was significantly reduced (P<0.05), and the expression of apoptosis promoter protein caspase 8 was also decreased. Compared with the the Normoxic+5-FU group, HIF-1α mRNA expression in the Hypoxia+5-FU group was significantly increased (P<0.05), and the mRNA and protein expression levels of MDR1, P-gp and VEGF were also significantly increased (all P<0.05). The increased expression of MDR1, P-gp and VEGF had the same trend with the expression of HIF-1α. CONCLUSIONS Hypoxia is a direct influencing factor in gastric cancer resistance to 5-FU chemotherapy. Improvement of the local hypoxia microenvironment of gastric cancer may be a new idea for overcoming the resistance to 5-FU in gastric cancer.
Humans ; Fluorouracil/therapeutic use* ; Vascular Endothelial Growth Factor A/metabolism* ; Stomach Neoplasms/drug therapy* ; Drug Resistance, Multiple ; Vascular Endothelial Growth Factors/metabolism* ; Hypoxia ; ATP Binding Cassette Transporter, Subfamily B/genetics* ; ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics* ; Cell Line, Tumor ; Cell Hypoxia ; RNA, Messenger/metabolism* ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; Tumor Microenvironment

OBJECTIVE: To investigate the role of myelin and lymphocyte protein (MAL) in pulmonary hypertension (PAH). METHODS: Blood samples were collected from 50 patients with PAH (PAH group) and 50 healthy individuals for detection of plasma MAL expression using ELISA.According to the echocardiographic findings, the patients were divided into moderate/severe group (n=18) and mild group (n=32), and the correlation between MAL protein level and the severity of PAH was analyzed.In a pulmonary artery smooth muscle cell model of PAH with hypoxia-induced abnormal proliferation, the effects of mal gene knockdown and overexpression on cell growth, proliferation and starvation-induced apoptosis were observed; the changes in NK-κB signaling pathway in the transfected cells were detected to explore the molecular mechanism by which MAL regulates PAMSC proliferation and apoptosis. RESULTS: The plasma level of MAL was significantly higher in patients with PAH than in healthy individuals (P < 0.05), and the patients with moderate/severe PAH had significantly higher MAL level than those with mild PAH (P < 0.001).In PAMSCs, exposure to hypoxia significantly increased the mRNA and protein expression levels of MAL (P < 0.05), and MAL knockdown obviously inhibited hypoxia-induced proliferation and promoted starvation-induced apoptosis of the PAMSCs (P < 0.05).Knocking down mal significantly inhibited the activation of NK-κB signaling pathway that participated in regulation of PAMSC proliferation (P < 0.05). CONCLUSION The plasma level of MAL is elevated in PAH patients in positive correlation with the disease severity.MAL knockdown inhibits abnormal proliferation and promotes apoptosis of PAMSCs by targeted inhibition of the NF-κB signaling pathway to improve vascular remodeling in PAH.
Humans ; Pulmonary Artery ; Hypertension, Pulmonary ; Myelin Sheath/metabolism* ; Apoptosis ; Myocytes, Smooth Muscle ; Vascular Remodeling/genetics* ; Cell Proliferation ; Hypoxia/metabolism* ; Lymphocytes

Intermittent hypoxia (IH) could induce cognitive impairment through oxidative stress and inflammation. However, the degree of cell damage is closely related to the IH stimulus frequency. IH stimulation with different frequencies also induces opposite results on neuronal cell lines. Therefore, this study was aimed to compare the effects of IH stimulation with three different frequencies on murine hippocampal neuronal HT22 cell activity, and to explore the molecular mechanism of the IH stimulus frequency-related neuron injury. HT22 cells were cultured and divided into control group and three IH stimulation groups with different frequencies. Oxygen concentration in the chamber was circulated between 21% and 1% (IH1 group, 6 cycles/h; IH2 group, 2 cycles/h; IH3 group, 0.6 cycle/h). Cell morphology was observed at 6, 12, 24 and 48 h of IH treatment. Cell viability was determined by the CCK-8 kit, lactate dehydrogenase (LDH) content in cell supernatant was determined by LDH kit, oxidative stress level was detected by the reactive oxygen species (ROS) probe, and protein expression levels of hypoxia inducible factor-1α (Hif-1α) and phosphorylated nuclear factor κB (p-NF-κB) were detected by Western blot. The results showed that, compared with control group, cell number and activity in the three IH groups were decreased, LDH content and ROS levels were increased with the prolongation of IH stimulation time, and the changes were most obvious in the IH1 group among those of the three IH groups. Hif-1α expression and the p-NF-κB/NF-κB ratio were also up-regulated with the prolongation of IH stimulation time, and the changes of IH1 group were the most significant. These results suggest that IH stimulation induces oxidative stress injury in HT22 cells, which is related to increased Hif-1α expression and NF-κB phosphorylation. Moreover, the higher frequency of IH stimulation induces more serious cell injury.
Animals ; Cell Hypoxia ; Cell Survival ; Hypoxia ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; Mice ; NF-kappa B/metabolism* ; Oxidative Stress ; Reactive Oxygen Species