1.Role of steroid receptor-associated and regulated protein in tumor progression and progesterone receptor signaling in endometrial cancer.
Jie LIU ; Zhiqi WANG ; Jingyi ZHOU ; Jiaqi WANG ; Xiangjun HE ; Jianliu WANG
Chinese Medical Journal 2023;136(21):2576-2586
BACKGROUND:
Steroid receptor-associated and regulated protein (SRARP) suppresses tumor progression and modulates steroid receptor signaling by interacting with estrogen receptors and androgen receptors in breast cancer. In endometrial cancer (EC), progesterone receptor (PR) signaling is crucial for responsiveness to progestin therapy. The aim of this study was to investigate the role of SRARP in tumor progression and PR signaling in EC.
METHODS:
Ribonucleic acid sequencing data from the Cancer Genome Atlas, Clinical Proteomic Tumor Analysis Consortium, and Gene Expression Omnibus were used to analyze the clinical significance of SRARP and its correlation with PR expression in EC. The correlation between SRARP and PR expression was validated in EC samples obtained from Peking University People's Hospital. SRARP function was investigated by lentivirus-mediated overexpression in Ishikawa and HEC-50B cells. Cell Counting Kit-8 assays, cell cycle analyses, wound healing assays, and Transwell assays were used to evaluate cell proliferation, migration, and invasion. Western blotting and quantitative real-time polymerase chain reaction were used to evaluate gene expression. The effects of SRARP on the regulation of PR signaling were determined by co-immunoprecipitation, PR response element (PRE) luciferase reporter assay, and PR downstream gene detection.
RESULTS:
Higher SRARP expression was significantly associated with better overall survival and disease-free survival and less aggressive EC types. SRARP overexpression suppressed growth, migration, and invasion in EC cells, increased E-cadherin expression, and decreased N-cadherin and Wnt family member 7A ( WNT7A ) expression. SRARP expression was positively correlated with PR expression in EC tissues. In SRARP -overexpressing cells, PR isoform B (PRB) was upregulated and SRARP bound to PRB. Significant increases in PRE-based luciferase activity and expression levels of PR target genes were observed in response to medroxyprogesterone acetate.
CONCLUSIONS
This study illustrates that SRARP exerts a tumor-suppressive effect by inhibiting the epithelial-mesenchymal transition via Wnt signaling in EC. In addition, SRARP positively modulates PR expression and interacts with PR to regulate PR downstream target genes.
Female
;
Humans
;
Receptors, Progesterone/metabolism*
;
Proteomics
;
Cell Line, Tumor
;
Endometrial Neoplasms/metabolism*
;
Cell Proliferation/genetics*
;
Luciferases/pharmacology*
;
Gene Expression Regulation, Neoplastic/genetics*
2.miR-23b-3p regulates the differentiation of goat intramuscular preadipocytes by targeting the PDE4B gene.
Liyi ZHANG ; Xin LI ; Qing XU ; Xinzhu HUANG ; Yanyan LI ; Wei LIU ; Youli WANG ; Yaqiu LIN
Chinese Journal of Biotechnology 2023;39(12):4887-4900
This study aimed to explore the effect of miR-23b-3p on the differentiation of goat intramuscular preadipocytes, and to confirm whether miR-23b-3p plays its roles via targeting the PDE4B gene. Based on the pre-transcriptome sequencing data obtained previously, the miR-23b-3p, which was differentially expressed in goat intramuscular adipocytes before and after differentiation, was used as an entry point. real-time quantitative-polymerase chain reaction (qPCR) was used to detect the expression pattern of miR-23b-3p during the differentiation of goat intramuscular preadipocytes. The effects of miR-23b-3p on adipose differentiation and adipose differentiation marker genes were determined at the morphological and molecular levels. The downstream target genes of miR-23b-3p were determined using bioinformatics prediction as well as dual luciferase reporter assay to clarify the targeting relationship between miR-23b-3p and the predicted target genes. The results indicated that overexpression of miR-23b-3p reduced lipid droplet accumulation in goat intramuscular adipocytes, significantly down-regulated the expression levels of adipogenic marker genes AP2, C/EBPα, FASN, and LPL (P < 0.01). In addition, the expressions of C/EBPβ, DGAT2, GLUT4 and PPARγ were significantly downregulated (P < 0.05). After interfering with the expression of miR-23b-3p, lipid droplet accumulation was increased in goat intramuscular adipocytes. The expression levels of ACC, ATGL, AP2, DGAT2, GLUT4, FASN and SREBP1 were extremely significantly up-regulated (P < 0.01), and the expression levels of C/EBPβ, LPL and PPARγ were significantly up-regulated (P < 0.05). It was predicted that PDE4B might be a target gene of miR-23b-3p. The mRNA expression level of PDE4B was significantly decreased after overexpression of miR-23b-3p (P < 0.01), and the interference with miR-23b-3p significantly increased the mRNA level of PDE4B (P < 0.05). The dual luciferase reporter assay indicated that miR-23b-3p had a targeting relationship with PDE4B gene. MiR-23b-3p regulates the differentiation of goat intramuscular preadipocytes by targeting the PDE4B gene.
Animals
;
MicroRNAs/metabolism*
;
Goats/genetics*
;
PPAR gamma/metabolism*
;
Adipogenesis/genetics*
;
Cell Differentiation/genetics*
;
Luciferases
;
RNA, Messenger
3.Matrine inhibits inflammatory response induced by TNF-α in human umbilical vein endothelial cells through miR-25-3p-mediated Klf4 pathway.
Zi-Ping XIANG ; Yan-Jie LI ; Huan MA ; Xing WANG ; Hui-Xin ZHANG ; Chao WANG
China Journal of Chinese Materia Medica 2023;48(17):4731-4737
This study aimed to analyze the effect of matrine on tumor necrosis factor-α(TNF-α)-induced inflammatory response in human umbilical vein endothelial cells(HUVECs) and explore whether the underlying mechanism was related to the miR-25-3p-mediated Krüppel-like factor 4(Klf4) pathway. The HUVEC cell inflammation model was induced by TNF-α stimulation. After 24 or 48 hours of incubation with different concentrations of matrine(0.625, 1.25, and 2.5 mmol·L~(-1)), CCK-8 assay was used to detect cell proliferation. After treatment with 2.5 mmol·L~(-1) matrine for 48 h, the expression of TNF-α, interleukin-6(IL-6), interleukin-1β(IL-1β), and Klf4 mRNA and miR-25-3p was detected by real-time fluorescence-based quantitative PCR, and the protein expression of TNF-α, IL-6, IL-1β, and Klf4 was detected by Western blot. The anti-miR-25-3p was transfected into HUVECs, and the effect of anti-miR-25-3p on TNF-α-induced cell proliferation and inflammatory factors was detected by the above method. The cells were further transfected with miR-25-3p and incubated with matrine to detect the changes in proliferation and expression of related inflammatory factors, miR-25-3p, and Klf4. The targeting relationship between miR-25-3p and Klf4 was verified by bioinformatics analysis and dual luciferase reporter gene assay. The results displayed that matrine could inhibit TNF-α-induced HUVEC proliferation, decrease the mRNA and protein expression of TNF-α, IL-6, and IL-1β, increase the mRNA and protein expression of Klf4, and reduce the expression of miR-25-3p. Bioinformatics analysis showed that there were specific complementary binding sites between miR-25-3p and Klf4 sequences. Dual luciferase reporter gene assay confirmed that miR-25-3p negatively regulated Klf4 expression in HUVECs by targeting. The inhibition of miR-25-3p expression can reduce TNF-α-induced cell proliferation and mRNA and protein expression of TNF-α, IL-6, and IL-1β. MiR-25-3p overexpression could reverse the effect of matrine on TNF-α-induced cell proliferation and the mRNA and protein expression of TNF-α, IL-6, IL-1β, and Klf4. This study shows that matrine inhibits the inflammatory response induced by TNF-α in HUVECs through miR-25-3p-mediated Klf4 pathway.
Humans
;
Tumor Necrosis Factor-alpha/metabolism*
;
MicroRNAs/metabolism*
;
Human Umbilical Vein Endothelial Cells
;
Matrines
;
Interleukin-6/genetics*
;
Signal Transduction
;
Antagomirs
;
Inflammation/metabolism*
;
Luciferases/pharmacology*
;
RNA, Messenger
;
Apoptosis
4.miR-181b-5p promotes cell proliferation and induces apoptosis in human acute myeloid leukemia by targeting PAX9.
Bin LI ; Qianshan TAO ; Xueying HU ; Tan LI ; Yangyi BAO
Chinese Journal of Cellular and Molecular Immunology 2023;39(12):1074-1082
Objective To investigate the effects of miR-181b-5p on cells proliferation and apoptosis in acute myeloid leukemia (AML) by targeting paired box 9 (PAX9). Methods The relationship between expression level of PAX9 and prognosis in AML patients was analyzed by gene expression profiling interactive analysis (GEPIA) database and The Cancer Genome Atlas (TCGA) database. Kasumi-1 and AML5 cells were transfected with empty vector (Vector group) or PAX9 (PAX9 group). The proliferation activity was detected by CCK-8 assay, and cells cycle and apoptosis were detected by flow cytometry. Expressions of cyclin-dependent kinase 2 (CDK2), cyclin B1 (CCNB1), B-cell lymphoma 2 (Bcl2) and Bcl2-associated X protein (BAX) were detected by Western blot analysis. The targeted microRNA (miRNA) by PAX9 was predicted by bioinformatics analysis, and the targeted effect was verified by luciferase reporter assay. The level of PAX9 mRNA was detected by real-time quantitative PCR, and expression of PAX9 protein was detected by Western blot analysis. Kasumi-1 and AML5 cells were transfected with miR-NC (miR-NC group) or miR-181b-5p (miR-181b-5p group). The cells were further transfected with PAX9 (miR-181b-5p combined with PAX9 group) in miR-181b-5p group. The proliferation, cycle and apoptosis of cells were detected by the above methods.Results GEPIA and TCGA databases showed that the expression of PAX9 was down-regulated in AML patients, which was correlated with poor prognosis. In Kasumi-1 and AML5 cells, compared with Vector group, proliferation activity of cells, percentage of cells in S phase, and expressions of CDK2, CCNB1 and Bcl2 proteins were decreased, while percentage of cells in G0/G1 phase, apoptosis rate and the expression of BAX protein were increased in PAX9 group. It was confirmed by double luciferase reporter assay that PAX9 was the target gene of miR-181b-5p. Compared with miR-NC group, proliferation activity of cells, percentage of cells in S phase, and expressions of CDK2, CCNB1 and Bcl2 proteins were increased, while percentage of cells in G0/G1 phase, apoptosis rate and the expression of BAX protein were decreased in miR-181b-5p group. Compared with miR-181b-5p group, proliferation activity of cells, percentage of cells in S phase, and expressions of CDK2, CCNB1 and Bcl2 proteins were decreased, while percentage of cells in G0/G1 phase, apoptosis rate and the expression of BAX protein were increased in miR-181b-5p combined with PAX9 group. Conclusion The miR-181b-5p can promote the proliferation of AML cells and delay apoptosis by inhibiting PAX9.
Humans
;
Apoptosis/genetics*
;
bcl-2-Associated X Protein
;
Cell Line, Tumor
;
Cell Proliferation/genetics*
;
Leukemia, Myeloid, Acute/pathology*
;
Luciferases
;
MicroRNAs/metabolism*
;
PAX9 Transcription Factor/genetics*
5.Effect of miR-125b on T Cell Activation in Aplastic Anemia by Targetting B7-H4.
Xiao LIU ; Xue-Xia WANG ; Hong-Kun SUN ; Na GAO ; Zeng-Yan LIU ; Xiao-Dan LIU
Journal of Experimental Hematology 2023;31(6):1797-1803
OBJECTIVE:
To investigate the effect of miR-125b on T cell activation in patients with aplastic anemia (AA) and its molecular mechanism.
METHODS:
A total of 30 AA patients were enrolled in department of hematology, Binzhou Medical University Hospital from January 2018 to October 2021, as well as 15 healthy individuals as healthy control (HC) group. Peripheral blood mononuclear cells (PBMCs) were isolated, in which the levels of miR-125b and B7-H4 mRNA were detected by RT-qPCR. Immunomagnetic beads were used to separate naive T cells and non-naive T cells from AA patients and healthy people to detect the levels of miR-125b and B7-H4 mRNA. Lentivirus LV-NC inhibitor and LV-miR-125b inhibitor were transfected into cells, and T cell activation was detected by flow cytometry. The dual-luciferase reporter gene assay was used to detect the targetting relationship between miR-125b and B7-H4. RT-qPCR and Western blot were used to detect the levels of miR-125b, CD40L, ICOS, IL-10 mRNA and B7-H4 protein.
RESULTS:
Compared with HC group, the expression of miR-125b was up-regulated but B7-H4 mRNA was down-regulated in PBMCs of AA patients (P <0.05), and the proportions of CD4+CD69+ T cells and CD8+CD69+ T cells in PBMCs of AA patients were higher (P <0.05). The expression of miR-125b was significantly up-regulated but B7-H4 mRNA was down-regulated in both naive T cells and non-naive T cells of AA patients (P <0.05), and non-naive T cells was more significant than naive T cells (P <0.05). Compared with NC inhibitor group, the expression of miR-125b was significantly decreased, the expression level of CD69 on CD4+ and CD8+ T cells in PBMCs was also significantly decreased, while the luciferase activity was significantly increased after co-transfection of miR-125b inhibitor and B7-H4-3'UTR-WT in the miR-125b inhibitor group (P <0.05). Compared with NC inhibitor group, the mRNA and protein levels of B7-H4 were significantly increased in the miR-125b inhibitor group (P <0.05). Compared with miR-125b inhibitor+shRNA group, the expression levels of CD69 on CD4+ and CD8+ T cells were significantly increased, and the levels of CD40L, ICOS and IL-10 mRNA were also significantly increased in the miR-125b inhibitor+sh-B7-H4 group (P <0.05).
CONCLUSION
MiR-125b may promote T cell activation by targetting B7-H4 in AA patients.
Humans
;
Anemia, Aplastic/genetics*
;
CD40 Ligand/metabolism*
;
Interleukin-10
;
Leukocytes, Mononuclear/metabolism*
;
Luciferases
;
MicroRNAs/genetics*
;
RNA, Messenger/metabolism*
;
Lymphocyte Activation
;
T-Lymphocytes/metabolism*
6.Porcine circovirus type 2 induces apoptosis by exosomal miR-125a-5p targeting Bcl-2 in porcine lymphocytes.
Dianning DUAN ; Huawei SHEN ; Yanmin PAN ; Rui FENG ; Lin ZHANG ; Lingguang LU ; Jiankui LIU ; Longxin QIU ; Hongbo CHEN
Chinese Journal of Biotechnology 2022;38(8):2891-2901
In order to investigate the apoptosis triggered by porcine circovirus type 2 (PCV2) in lymphocytes and the underlying mechanism, the levels of apoptosis and the expression levels of miRNA were examined by flow cytometry, Western blotting and real-time PCR (qPCR). The mimics or inhibitors of miR-125a-5p, an apoptosis-related miRNA, were transfected into PK-15 cells, and the apoptosis rate was examined upon overexpression or inhibition of mir-125a-5p. The target gene of mir-125a-5p was predicted by bioinformatics method, and the regulation of mir-125a-5p on the target gene was analyzed by luciferase reporter assay. The expressions of Bcl-2, Bax, cytochrome C and caspase-3 were detected by Western blotting. The results showed that exosomes secreted by PK-15 cells infected with PCV2 significantly increased the lymphocyte apoptosis rate, which was dose-dependent in certain concentration range. The expression of miR-125a-5p was dramatically increased. The apoptosis rate was increased significantly in the cells transfected with miR-125a-5p. It was predicted that there were binding sites of miR-125a-5p at Bcl-2 3'UTR by TargetScan. The luciferase activity of wild-type pmir-Bcl-2 3'UTR was inhibited significantly by miR-125a-5p mimics, but that of mutant pmir-Bcl-2 3'UTR was not changed. By Western blotting, Bcl-2 was reduced significantly, while Bax, cytochrome C and caspase-3 increased significantly, and the ratio of Bcl-2/Bax was significantly decreased. These results showed that PCV2 up-regulated the expression of miR-125a-5p through exosomes, then inhibited the expression of Bcl-2 at both mRNA and protein level, activated mitochondrial apoptosis pathway and induced apoptosis in lymphocytes.
3' Untranslated Regions
;
Animals
;
Apoptosis/genetics*
;
Caspase 3/genetics*
;
Cell Proliferation/genetics*
;
Circovirus/genetics*
;
Cytochromes c/genetics*
;
Luciferases/genetics*
;
Lymphocytes/metabolism*
;
MicroRNAs/metabolism*
;
Swine
;
bcl-2-Associated X Protein/genetics*
7.Preparation of luciferase-expressing mRNA and expression characteristics of mRNA delivered by electroporation in vivo.
Lingjiang FAN ; Keru ZHOU ; Yanguang LIU ; Guiqin WANG ; Ting SHI ; Yihong HU ; Daixi LI
Chinese Journal of Biotechnology 2022;38(9):3379-3389
In this study, we aimed to construct a non-replication mRNA platform and explore the side effects of electroporation-mediated delivery of mRNA on the mice as well as the expression features of the mRNA. With luciferase gene as a marker, in vitro transcription with T7 RNA polymerase was carried out for the synthesis of luciferase-expressed mRNA, followed by enzymatic capping and tailing. The mRNA was delivered in vivo by electroporation via an in vivo gene delivery system, and the expression intensity and duration of luciferase in mice were observed via an in vivo imaging system. The results demonstrated that the mRNA transcripts were successfully expressed both in vitro and in vivo. The electroporation-mediated delivery of mRNA had no obvious side effects on the mice. Luciferase was expressed successfully in all the mRNA-transduced mice, while the expression intensity and duration varied among individuals. Overall, the expression level peaked on the first day after electroporation and rapidly declined on the fourth day. This study is of great importance for the construction of non-replication mRNAs and their application in vaccine or antitumor drug development.
Animals
;
Electroporation/methods*
;
Gene Transfer Techniques
;
Luciferases/metabolism*
;
Mice
;
RNA, Messenger/genetics*
8.MiR-21 Regulates the Proliferation of Multiple Myeloma Cells by Inhibiting the Expression of KLF5.
Nan ZHOU ; Shu-Xing CAO ; Jian-Min LUO ; Xiao-Jun LIU ; Lin YANG
Journal of Experimental Hematology 2022;30(5):1482-1489
OBJECTIVE:
To study the expression of miR-21 in multiple myeloma (MM) cell lines and plasma cells of patients, and explore the mechanism of miR-21 in MM.
METHODS:
Bone marrow samples from 30 patients with MM and 18 healthy controls were collected. The plasma cells were separated by magnetic beads. MM cell lines (MM1.S cells, RPMI-8226 cells and U266 cells) were cultured. The expression level of miR-21 was detected by real-time fluorescent quantitative PCR (qRT-PCR). After transfection with hsa-miR-21 mimics and hsa-miR-21 inhibitor, the proliferation of MM cells was detected by CCK-8 and cell cloning assay. The target genes regulated by miR-21 were predicted by bioinformatics website. The binding sites of miR-21 and KLF5 were detected by luciferase reporter gene assay. The expression of KLF5 were detected by Western blot and qRT-PCR after hsa-miR-21 mimics and hsa-miR-21 inhibitor were transfected into RPMI-8226 cells. KLF5 plasmid with 3'UTR knockout was synthesized and cotransfected into RPMI-8226 cells with hsa-miR-21 mimics, and the proliferation of MM cells was detected by CCK-8 and cell cloning assay.
RESULTS:
Compared with healthy donors, the expression level of miR-21 in plasma cells of patients with MM was significantly increased (P<0.001); the expression of miR-21 in MM cell lines MM1.S, RPMI-8226 and U266 was significantly higher than that in control group (P<0.05). After hsa-miR-21 mimics transfection, the proliferation and the number of colony formation of MM cells was significantly increased, while the proliferation and the number of colony formation of MM cells was decreased after hsa-miR-21 inhibitor transfection (P<0.01). The results of luciferase reporter gene assay showed that miR-21 could bind to 3'UTR of KLF5, and the expression level of KLF5 protein was significantly decreased after hsa-miR-21 mimics transfection. After 3'UTR-knockout KLF5 plasmid and hsa-miR-21 mimics were cotransfected into RPMI-8226 cells, the proliferation of the cells was significantly decreased.
CONCLUSION
MiR-21 may be involved in regulating the proliferation of MM cells by inhibiting the expression of KLF5.
3' Untranslated Regions
;
Cell Line, Tumor
;
Cell Proliferation
;
Humans
;
Kruppel-Like Transcription Factors
;
Luciferases/genetics*
;
MicroRNAs/metabolism*
;
Multiple Myeloma/genetics*
;
Sincalide/genetics*
9.Expression of miR-4324 and its targeted gene Talin2 in breast cancer.
Peng GAO ; Hai Tao ZHU ; Wen Hao PEI ; Pei Hai XU ; Yong Xing DING
Journal of Southern Medical University 2022;42(10):1517-1525
OBJECTIVE:
To investigate the regulatory effect of miR-4324 on ankyrin 2(Talin2) expression and biological behaviors of breast cancer cells and the clinical implications of changes in miR-4324 and Talin2 expressions in breast cancer.
METHODS:
In breast cancer and adjacent tissues, the expressions of Talin2 and miR-4324 were examined with immunohistochemistry and qRT-PCR, respectively and the association of Talin2 expression levels with the prognosis and clinicopathological features of breast cancer patients was analyzed.The human breast cancer cell line SKBR-3 was transfected with miR-4324 mimic, miR-4324 inhibitor, si-Talin2, or both miR-4324 inhibitor and si-Talin2, and the changes in biological behaviors of the cells were examined; the cellular expression of Talin2at the mRNA and protein levels were detected with qRT-PCR and Western blotting.Dual luciferase reporter gene assay was used to verify the targeting relationship between miR-4324 and Talin2.The effect of miR-4324-mediated regulation of Talin2 on SKBR-3 cell migration was assessed using Transwell assays.
RESULTS:
Talin2 expression was significantly higher in breast cancer tissues than in the adjacent tissues, and its expression level was correlated with lymph node metastasis and high HER-2 expression in breast cancer (P < 0.05) but not with the patient's age, clinical stage, histological grade or expressions of estrogen and progesterone receptors (P >0.05).The expression of miR-4324 was significantly reduced in breast cancer tissues as compared with the adjacent tissues (P < 0.01).In SKBR-3 cells, transfection with miR-4324 mimics significantly inhibited proliferation, migration and invasion (P < 0.05) and promoted apoptosis (P < 0.01) of the cells.Dual luciferase reporter gene assay confirmed that cotransfection with miR-4324 mimics significantly reduced luciferase activity of Talin2-3'-UTR WT reporter plasmid (P < 0.05).Transfection of the cells with miR-4324 mimics significantly reduced mRNA and protein expressions of Talin2(P < 0.05).Transwell migration assay showed that the migration ability of SKBR-3 cells was significantly enhanced after transfection with miR-4324 inhibitor (P < 0.01), lowered after transfection with si-Talin2(P < 0.01), and maintained at the intermediate level after co-transfection with miR-4324 inhibitor+si-Talin2 group (P < 0.05).
CONCLUSIONS
High expression of Talin2 is associated with lymph node metastasis and HER-2 overexpression in breast cancer patients.Down-regulation of miR-4324 inhibits the proliferation, invasion and migration and induces apoptosis of breast cancer cells, and the inhibitory effect of miR-4324 knockdown on breast cancer cell migration is mediated probably by targeted inhibition of Talin2 expression.
Female
;
Humans
;
Breast Neoplasms/pathology*
;
Cell Line, Tumor
;
Cell Movement/genetics*
;
Cell Proliferation/genetics*
;
Gene Expression Regulation, Neoplastic
;
Luciferases/genetics*
;
Lymphatic Metastasis
;
MicroRNAs/metabolism*
;
Neoplasm Invasiveness/genetics*
;
RNA, Messenger
10.VIPR1 promoter methylation promotes transcription factor AP-2α binding to inhibit VIPR1 expression and promote hepatocellular carcinoma cell growth in vitro.
Shi Yu NING ; Chun Mei HE ; Ze Hao GUO ; Hao ZHANG ; Zhi Jing MO
Journal of Southern Medical University 2022;42(7):957-965
OBJECTIVE:
To explore the transcriptional regulation mechanism and biological function of low expression of vasoactive intestinal peptide receptor 1 (VIPR1) in hepatocellular carcinoma (HCC).
METHODS:
We constructed plasmids carrying wild-type VIPR1 promoter or two mutant VIPR1 promoter sequences for transfection of the HCC cell lines Hep3B and Huh7, and examined the effect of AP-2α expression on VIPR1 promoter activity using dual-luciferase reporter assay. Pyrosequencing was performed to detect the changes in VIPR1 promoter methylation level in HCC cells treated with a DNA methyltransferase inhibitor (DAC). Chromatin immunoprecipitation was used to evaluate the binding ability of AP-2α to VIPR1 promoter. Western blotting was used to assess the effect of AP-2α knockdown on VIPR1 expression and examine the differential expression of VIPR1 in the two cell lines. The effects of VIPR1 overexpression and knockdown on the proliferation, cell cycle and apoptosis of HCC cells were analyzed using CCK8 assay and flow cytometry. We also observed the growth of HCC xenograft with lentivirus-mediated over-expression of VIPR1 in nude mice.
RESULTS:
Compared with the wild-type VIPR1 promoter group, co-transfection with the vector carrying two promoter mutations and the AP-2α-over-expressing plasmid obviously restored the luciferase activity in HCC cells (P < 0.05). DAC treatment of the cells significantly decreased the methylation level of VIPR1 promoter and inhibited the binding of AP-2α to VIPR1 promoter (P < 0.01). The HCC cells with AP-2α knockdown showed increased VIPR1 expression, which was lower in Huh7 cells than in Hep3B cells. VIPR1 overexpression in HCC cells caused significant cell cycle arrest in G2/M phase (P < 0.01), promoted cell apoptosis (P < 0.001), and inhibited cell proliferation (P < 0.001), while VIPR1 knockdown produced the opposite effects. In the tumor-bearing nude mice, VIPR1 overexpression in the HCC cells significantly suppressed the increase of tumor volume (P < 0.001) and weight (P < 0.05).
CONCLUSION
VIPR1 promoter methylation in HCC promotes the binding of AP-2α and inhibits VIPR1 expression, while VIPR1 overexpression causes cell cycle arrest, promotes cell apoptosis, and inhibits cell proliferation and tumor growth.
Animals
;
Carcinoma, Hepatocellular/pathology*
;
Cell Line, Tumor
;
Cell Proliferation/genetics*
;
Gene Expression Regulation, Neoplastic
;
Humans
;
Liver Neoplasms/pathology*
;
Luciferases/genetics*
;
Methylation
;
Mice
;
Mice, Nude
;
Receptors, Vasoactive Intestinal Polypeptide, Type I/metabolism*
;
Transcription Factor AP-2/metabolism*

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