Chemotherapy-initiated cysteine-rich protein 61 decreases acute B-lymphoblastic leukemia chemosensitivity.

PURPOSE: Chemoresistance is a major challenge for acute lymphoblastic leukemia (ALL) treatment. Cysteine-rich protein 61 (Cyr61) plays an important role in drug resistance modulation of tumor cells, and Cyr61 levels are increased in the bone marrow of patients with ALL and contribute to ALL cell survival. However, the effect of Cyr61 on B cell acute lymphoblastic leukemia (B-ALL) cell chemosensitivity and the regulatory mechanisms underlying Cyr61 production in bone marrow remain unknown. METHODS: Nalm-6 and Reh human B-ALL cell lines were used in this study. Cyr61 levels were assessed using quantitative real-time PCR (qRT-PCR), western blot analysis, and enzyme-linked immunosorbent assay. The effect of Cyr61 on B-ALL cell chemosensitivity to daunorubicin (DNR) was evaluated using cell viability and flow cytometry analyses. The regulatory mechanisms of Cyr61 production in bone marrow were examined using qRT-PCR and western blot analysis. RESULTS: Cyr61 knockdown and overexpression increased and decreased the chemosensitivity of B-ALL cells to DNR, respectively. Cyr61 attenuated chemotherapeutic drug-induced apoptosis by upregulating B cell lymphoma-2. Notably, DNR induced DNA damage response and increased Cyr61 secretion in B-ALL cells through the ataxia telangiectasia mutated (ATM)-dependent nuclear factor kappa B pathway. CONCLUSION: DNR induces Cyr61 production in B-ALL cells, and increased Cyr61 levels reduce the chemosensitivity of B-ALL cells. Consequently, targeting Cyr61 or related ATM signaling pathway may present a promising treatment strategy to enhance the chemosensitivity of patients with B-ALL.

Upregulation of CYR61 by TGF-ß and YAP signaling exerts a counter-suppression of hepatocellular carcinoma.

Transforming growth factor-ß (TGF-ß) and Hippo signaling are two critical pathways engaged in cancer progression by regulating both oncogenes and tumor suppressors, yet how the two pathways coordinately exert their functions in the development of hepatocellular carcinoma (HCC) remains elusive. In this study, we firstly conducted an integrated analysis of public liver cancer databases and our experimental TGF-ß target genes, identifying CYR61 as a pivotal candidate gene relating to HCC development. The expression of CYR61 is downregulated in clinical HCC tissues and cell lines than that in the normal counterparts. Evidence revealed that CYR61 is a direct target gene of TGF-ß in liver cancer cells. In addition, TGF-ß-stimulated Smad2/3 and the Hippo pathway downstream effectors YAP and TEAD4 can form a protein complex on the promoter of CYR61, thereby activating the promoter activity and stimulating CYR61 gene transcription in a collaborative manner. Functionally, depletion of CYR61 enhanced TGF-ß- or YAP-mediated growth and migration of liver cancer cells. Consistently, ectopic expression of CYR61 was capable of impeding TGF-ß- or YAP-induced malignant transformation of HCC cells in vitro and attenuating HCC xenograft growth in nude mice. Finally, transcriptomic analysis indicates that CYR61 can elicit an antitumor program in liver cancer cells. Together, these results add new evidence for the crosstalk between TGF-ß and Hippo signaling and unveil an important tumor suppressor function of CYR61 in liver cancer.

Global Proteomics Analysis of Lysophosphatidic Acid Signaling in PC-3 Human Prostate Cancer Cells: Role of CCN1.

Cysteine-rich angiogenic factor 61 (CCN1/Cyr61) is a matricellular protein that is induced and secreted in response to growth factors. Our previous work showed that 18:1-lysophosphatidic acid (LPA), which activates the G protein-coupled receptor LPAR1, induces CCN1 between 2-4 h in PC-3 human prostate cancer cells in a manner than enhances cell-substrate adhesion. While the time course of induction suggests that CCN1 contributes to intermediate events in LPA action, the roles of CCN1 in LPA-mediated signal transduction have not been fully elucidated. This study utilized a comprehensive global proteomics approach to identify proteins up- or down-regulated in response to treatment of PC-3 cells with LPA for three hours, during the time of peak CCN1 levels. In addition, the effects of siRNA-mediated CCN1 knockdown on LPA responses were analyzed. The results show that, in addition to CCN1, LPA increased the levels of multiple proteins. Proteins up-regulated by LPA included metastasis-associated in colon cancer protein 1 (MACC1) and thrombospondin-1 (TSP1/THBS1); both MACC1 and TSP1 regulated cancer cell adhesion and motility. LPA down-regulated thioredoxin interacting protein (TXNIP). CCN1 knockdown suppressed the LPA-induced up-regulation of 30 proteins; these included MACC1 and TSP1, as confirmed by immunoblotting. Gene ontology and STRING analyses revealed multiple pathways impacted by LPA and CCN1. These results indicate that CCN1 contributes to LPA signaling cascades that occur during the intermediate phase after the initial stimulus. The study provides a rationale for the development of interventions to disrupt the LPA-CCN1 axis.

Cancer-associated Fibroblast-specific Expression of the Matricellular Protein CCN1 Coordinates Neovascularization and Stroma Deposition in Melanoma Metastasis.

Melanoma is the leading cause of skin cancer-related death. As prognosis of patients with melanoma remains problematic, identification of new therapeutic targets remains essential. Matricellular proteins are nonstructural extracellular matrix proteins. They are secreted into the tumor microenvironment to coordinate behavior among different cell types, yet their contribution to melanoma is underinvestigated. Examples of matricellular proteins include those comprising the CCN family. The CCN family member, CCN1, is highly proangiogenic. Herein, we show that, in human patients with melanoma, although found in several tumor cell types, CCN1 is highly expressed by a subset of cancer-associated fibroblasts (CAF) in patients with melanoma and this expression correlates positively with expression of proangiogenic genes and progressive disease/resistance to anti-PD1 checkpoint inhibitors. Consistent with these observations, in a syngeneic C57BL6 mouse model of melanoma, loss of CCN1 expression from Col1A2-Cre-, herein identified as "universal," fibroblasts, impaired metastasis of subcutaneously injected B16F10 tumor cells to lung, concomitant with disrupted neovascularization and collagen organization. Disruption of the extracellular matrix in the loss of CCN1 was validated using a novel artificial intelligence-based image analysis platform that revealed significantly decreased phenotypic fibrosis and composite morphometric collagen scores. As drug resistance is linked to matrix deposition and neoangiogenesis, these data suggest that CCN1, due to its multifaceted role, may represent a novel therapeutic target for drug-resistant melanoma. Our data further emphasize the essential role that cancer-associated, (universal) Col1A2-Cre-fibroblasts and extracellular matrix remodeling play in coordinating behavior among different cell types within the tumor microenvironment. SIGNIFICANCE: In human patients, the expression of proangiogenic matricellular protein CCN1 in CAFs correlates positively with expression of stroma and angiogenic markers and progressive disease/resistance to checkpoint inhibitor therapy. In an animal model, loss of CCN1 from CAFs impaired metastasis of melanoma cells, neovascularization, and collagen deposition, emphasizing that CAFs coordinate cellular behavior in a tumor microenvironment and that CCN1 may be a novel target.

Cysteine-rich 61(CYR61) alleviates cyclophosphamide-induced proliferation inhibition in ovarian granulosa cells via suppressing NLRP3/caspase1-mediated pyroptosis.

BACKGROUND: We investigated the level of Cysteine-rich 61 (CYR61) in premature ovarian failure as well as its regulatory molecular mechanism in this study. METHODS AND RESULTS: Cyclophosphamide (CTX) was used to induce OGCs (rat ovarian granulosa cells) and rats to establish in vivo and in vitro premature ovarian failure models. H&E staining was used to detect the pathological changes of ovarian histopathology. Si-NLRP3 (NOD-like receptor thermal protein domain associated protein 3, NLRP3) and si-CYR61 were transfected into OGCs using lipofectamine 3000. RT-qPCR and western blot were used to detect the expressions of CYR61 in ovarian tissue and OGCs. It showed that the expression of CYR61 was significantly down-regulated in premature ovarian failure model. Cell viability was detected using a Cell Counting Kit-8 (CCK-8) kit. TUNEL (Terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling) staining was used to detect the apoptosis. 5-Ethynyl-2'-deoxyuridine (EdU) and SA-ß-gal (senescence-associated ß-galactosidase) staining were used to assess the proliferation and senescence. The expression of CYR61 in OGCs and ovarian tissues were detected by immunofluorescence and immunohistochemical staining. Overexpression of CYR61 significantly promoted OGCs proliferation and inhibited pyroptosis and apoptosis. Western blot was used to detect the protein expressions of p53 and p21 in OGCs. Flow cytometry was used to detect the pyroptosis. CYR61 overexpression inhibited the expression of NLRP3 and caspase-1 in CTX-induced OGCs according to western blot results. Moreover, we found that CYR61 overexpression down-regulated the protein expressions of p53 and p21 in CTX-induced OGCs. CONCLUSION: CYR61 inhibited CTX-induced OGCs senescence, and the mechanism may be related to the regulation of caspase-1/NLRP3-induced pyroptosis.

Targeting the splicing factor NONO inhibits GBM progression through GPX1 intron retention.

Background: Splicing factors are essential for nascent pre-mRNA processing and critical in cancer progression, suggesting that proteins with splicing functions represent potential molecular targets for cancer therapy. Here, we investigate the role of splicing factors in glioblastoma multiforme (GBM) progression and the possibility of targeting them for the treatment of the disease. Methods: The TCGA and CGGA public databases were used to screen for differentially expressed mRNA splicing factors. Immunohistochemistry and qRT-PCR were used to analyze the expression of non-POU domain-containing octamer-binding protein (NONO), a Drosophila behavior human splicing (DBHS) protein. Knockdown/overexpression of NONO with siRNA and lentiviral expression constructs was used to examine cell growth, apoptosis, and invasion in GBM cells. RNA sequencing was used to identify potential downstream molecular targets of NONO. RIP-PCR and RNA pulldown were used to determine the interaction between NONO and pre-mRNA. JC-1 staining and the seahorse assay were performed to assess redox homeostasis. Results: Expression of NONO was increased in GBM samples and associated with poor survival in patients (P = 0.04). Knockdown of NONO suppressed GBM growth, and overexpression of NONO promoted GBM tumorigenesis in vitro and in vivo. RNA sequencing-based transcriptomic profiling confirmed that knockdown of NONO in U251 and P3 cells resulted in global intron retention of pre-mRNA and led to abnormal splicing of specific pre-mRNAs for GPX1 and CCN1. NONO bound to a consensus motif in the intron of GPX1 pre-mRNA in association with another DBHS protein family member, PSPC1. Knockdown of NONO impaired tumor growth, invasion, and redox homeostasis through aberrant splicing of GPX1. Finally, Auranofin, a small molecule inhibitor of NONO, suppressed GBM tumor growth in an orthotopic xenograft model in mice. Conclusions: We demonstrated that intron retention was a critical alternative RNA splicing event to occur in GBM progression, and that NONO was a key regulator of mRNA splicing in GBM. Targeting NONO represents a novel, potential therapeutic strategy for GBM treatment.

[Scutellarin alleviates lipopolysaccharide-induced renal injury via mediating cysteine-rich protein 61-connective tissue growth factor-nephroblastoma overexpressed gene 1 expression to inhibit nuclear factor-κB signaling pathway].

OBJECTIVE: To explore the protective effect and mechanism of scutellarin (Scu) on sepsis associated-acute kidney injury (SA-AKI). METHODS: (1) In vivo experiment: 36 male C57BL/6 mice were divided into normal saline (NS) control group, lipopolysaccharide (LPS) induced SA-AKI model group (LPS group), 20 mg/kg Scu control group (Scu 20 control group), and 5, 10, 20 mg/kg Scu pretreatment groups by random number table with 6 mice in each group. The SA-AKI model was reproduced by intraperitoneal injection of 10 mg/kg LPS. The NS control group was injected with NS intraperitoneally. The Scu pretreatment groups were intraperitoneally injected with different doses of Scu every day before LPS injection for 1 week. Scu 20 control group was injected with 20 mg/kg Scu for 1 week. After 24 hours of LPS treatment, mice in each group were sacrificed, kidney tissues were collected, and kidney injury was detected by hematoxylin-eosin (HE) staining. Western blotting was used to detect the protein expression levels of nuclear factor-κB (NF-κB) signaling pathway related molecules, apoptosis-related proteins and cysteine-rich protein 61-connective tissue growth factor-nephroblastoma overexpressed gene 1 (CCN1). (2) In vitro experiment: human renal tubular epithelial cell line HK-2 was cultured in vitro and used for experiment when the cells fused to 80%. In the cells without LPS treatment and after 100 g/L LPS treatment, pcDNA3.1-CCN1 and small interfering RNA (siRNA) CCN1 sequence were transfected to overexpress and inhibit CCN1 expression, respectively, to observe whether CCN1 was involved in NF-κB signaling pathway activation and apoptosis. In addition, 100g/L LPS and 20 µmol/L Scu were added into HK-2 cells transfected with and without CCN1 siRNA to investigate the mechanism of protective effect of Scu on LPS-induced HK-2 cells injury. RESULTS: (1) The results of in vivo experiment: the renal function of SA-AKI mice induced by LPS was significantly decreased, and had kidney histological damage and severely damaged renal tubules. Scu could alleviate renal function and histological damage in a dose-dependent manner. Western blotting results showed Scu could reduce the protein expression of NF-κB signaling pathway related molecules and CCN1 in the renal tissue, and had a significant alleviating effect on apoptosis, indicating that CCN1 was involved in NF-κB signaling pathway activation and apoptosis. (2) The results of in vitro experiment: in HK-2 cells not treated with LPS, CCN1 overexpression had no effect on apoptosis related protein and pro-inflammatory factors of NF-κB signaling pathway. In HK-2 cells treated with LPS, overexpression of CCN1 significantly inhibited the mRNA expressions of interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), with significant differences as compared with cells stimulated only by LPS [IL-1ß mRNA (2-ΔΔCT): 3.20±0.57 vs. 4.88±0.69, TNF-α mRNA (2-ΔΔCT): 2.99±0.44 vs. 5.00±0.81, MCP-1 mRNA (2-ΔΔCT): 2.81±0.50 vs. 5.41±0.75, all P < 0.05], and the apoptosis-related protein was significantly down-regulated. However, when siRNA was used to inhibit the expression of CCN1, the mRNA expressions of pro-inflammatory factors were significantly increased as compared with cells stimulated only by LPS [IL-1ß mRNA (2-ΔΔCT): 6.01±1.13 vs. 4.88±0.69, TNF-α mRNA (2-ΔΔCT): 5.15±0.86 vs. 5.00±0.81, all P < 0.05], and apoptosis-related protein was significantly up-regulated. In the LPS-induced HK-2 cells, the mRNA expressions of pro-inflammatory factors were significantly down-regulated after Scu treatment as compared with cells stimulated only by LPS [IL-1ß mRNA(2-ΔΔCT): 2.55±0.50 vs. 6.15±1.04, TNF-α mRNA (2-ΔΔCT): 2.58±0.40 vs. 3.95±0.52, MCP-1 mRNA (2-ΔΔCT): 2.64±0.44 vs. 6.21±0.96, all P < 0.05], and apoptosis-related protein was also significantly reduced. When the expression of CCN1 was inhibited by siRNA, the protective effect of Scu on cells was weakened, which showed that the mRNA expressions of pro-inflammatory factors in cells was significantly up-regulated compared with the cells without inhibition of CCN1 expression [IL-1ß mRNA (2-ΔΔCT): 5.34±0.76 vs. 2.55±0.50, TNF-α mRNA (2-ΔΔCT): 3.66±0.54 vs. 2.58±0.40, MCP-1 mRNA (2-ΔΔCT): 5.15±0.79 vs. 2.64±0.44, all P < 0.05], and the expression of apoptosis related protein was also significantly up-regulated. CONCLUSIONS: Scu could protect the renal function in SA-AKI mice, and the protective effect is associated with NF-κB signaling pathway and CCN1. Thus, Scu could alleviate LPS-induced kidney injury by regulating the NF-κB signaling pathway.

Matrix-bound Cyr61/CCN1 is required to retain the properties of the bone marrow mesenchymal stem cell niche but is depleted with aging.

Previously, we showed that extracellular matrices (ECMs), produced ex vivo by various types of stromal cells, direct bone marrow mesenchymal stem cells (BM-MSCs) in a tissue-specific manner and recapitulate physiologic changes characteristic of the aging microenvironment. In particular, BM-MSCs obtained from elderly donors and cultured on ECM produced by young BM stromal cells showed improved quantity, quality and osteogenic differentiation. In the present study, we searched for matrix components that are required for a functional BM-MSC niche by comparing ECMs produced by BM stromal cells from "young" (≤25 y/o) versus "elderly" (≥60 y/o) donors. With increasing donor age, ECM fibrillar organization and mechanical integrity deteriorated, along with the ability to promote BM-MSC proliferation and responsiveness to growth factors. Proteomic analyses revealed that the matricellular protein, Cyr61/CCN1, was present in young, but undetectable in elderly, BM-ECM. To assess the role of Cyr61 in the BM-MSC niche, we used genetic methods to down-regulate the incorporation of Cyr61 during production of young ECM and up-regulate its incorporation in elderly ECM. The results showed that Cyr61-depleted young ECM lost the ability to promote BM-MSC proliferation and growth factor responsiveness. However, up-regulating the incorporation of Cyr61 during synthesis of elderly ECM restored its ability to support BM-MSC responsiveness to osteogenic factors such as BMP-2 and IGF-1. We next examined aging bone and compared bone mineral density and Cyr61 content of L4-L5 vertebral bodies in "young" (9-11 m/o) and "elderly" (21-33 m/o) mice. Our analyses showed that low bone mineral density was associated with decreased amounts of Cyr61 in osseous tissue of elderly versus young mice. Our results strongly demonstrate a novel role for ECM-bound Cyr61 in the BM-MSC niche, where it is responsible for retention of BM-MSC proliferation and growth factor responsiveness, while depletion of Cyr61 from the BM niche contributes to an aging-related dysregulation of BM-MSCs. Our results also suggest new potential therapeutic targets for treating age-related bone loss by restoring specific ECM components to the stem cell niche.

Involvement of CCN1 Protein and TLR2/4 Signaling Pathways in Intestinal Epithelial Cells Response to Listeria monocytogenes.

CCN1 is well studied in terms of its functions in injury repair, cell adhesion survival and apoptosis, bacterial clearance and mediation of inflammation-related pathways, such as the TLR2/4 pathways. However, the role of CCN1 protein and its interaction with TLR2/4 pathways in intestinal epithelial cells was not elucidated after Listeria monocytogenes infection. The results of this study confirm that L. monocytogenes infection induced intestinal inflammation and increased the protein expression of CCN1, TLR2, TLR4 and p38, which followed a similar tendency in the expression of genes related to the TLR2/4 pathways. In addition, organoids infected by L. monocytogenes showed a significant increase in the expression of CCN1 and the activation of TLR2/4 pathways. Furthermore, pre-treatment with CCN1 protein to organoids infected by L. monocytogenes could increase the related genes of TLR2/4 pathways and up-regulate the expression of TNF, and increase the count of pathogens in organoids, which indicates that the interaction between the CCN1 protein and TLR2/4 signaling pathways in intestinal epithelial cells occurred after L. monocytogenes infection. This study will provide a novel insight of the role of CCN1 protein after L. monocytogenes infection in the intestine.

Binding of the angiogenic/senescence inducer CCN1/CYR61 to integrin α6ß1 drives endocrine resistance in breast cancer cells.

CCN1/CYR61 promotes angiogenesis, tumor growth and chemoresistance by binding to its integrin receptor αvß3 in endothelial and breast cancer (BC) cells. CCN1 controls also tissue regeneration by engaging its integrin receptor α6ß1 to induce fibroblast senescence. Here, we explored if the ability of CCN1 to drive an endocrine resistance phenotype in estrogen receptor-positive BC cells relies on interactions with either αvß3 or α6ß1. First, we took advantage of site-specific mutagenesis abolishing the CCN1 receptor-binding sites to αvß3 and α6ß1 to determine the integrin partner responsible for CCN1-driven endocrine resistance. Second, we explored a putative nuclear role of CCN1 in regulating ERα-driven transcriptional responses. Retroviral forced expression of a CCN1 derivative with a single amino acid change (D125A) that abrogates binding to αvß3 partially phenocopied the endocrine resistance phenotype induced upon overexpression of wild-type (WT) CCN1. Forced expression of the CCN1 mutant TM, which abrogates all the T1, H1, and H2 binding sites to α6ß1, failed to bypass the estrogen requirement for anchorage-independent growth or to promote resistance to tamoxifen. Wild-type CCN1 promoted estradiol-independent transcriptional activity of ERα and enhanced ERα agonist response to tamoxifen. The α6ß1-binding-defective TM-CCN1 mutant lost the ERα co-activator-like behavior of WT-CCN1. Co-immunoprecipitation assays revealed a direct interaction between endogenous CCN1 and ERα, and in vitro approaches confirmed the ability of recombinant CCN1 to bind ERα. CCN1 signaling via α6ß1, but not via αvß3, drives an endocrine resistance phenotype that involves a direct binding of CCN1 to ERα to regulate its transcriptional activity in ER+ BC cells.

Cezanne is a critical regulator of pathological arterial remodelling by targeting ß-catenin signalling.

AIMS: Pathological arterial remodelling including neointimal hyperplasia and atherosclerosis is the main underlying cause for occluding arterial diseases. Cezanne is a novel deubiquitinating enzyme, functioning as a NF-кB negative regulator, and plays a key role in renal inflammatory response and kidney injury induced by ischaemia. Here we attempted to examine its pathological role in vascular smooth muscle cell (VSMC) pathology and arterial remodelling. METHODS AND RESULTS: Cezanne expression levels were consistently induced by various atherogenic stimuli in VSMCs, and in remodelled arteries upon injury. Functionally, VSMCs over-expressing wild-type Cezanne, but not the mutated catalytically-inactive Cezanne (C209S), had an increased proliferative ability and mobility, while the opposite was observed in VSMCs with Cezanne knockdown. Surprisingly, we observed no significant effects of Cezanne on VSMC apoptosis, NF-κB signalling, or inflammation. RNA-sequencing and biochemical studies showed that Cezanne drives VSMC proliferation by regulating CCN family member 1 (CCN1) by targeting ß-catenin for deubiquitination. Importantly, local correction of Cezanne expression in the injured arteries greatly decreased VSMC proliferation, and prevented arterial inward remodelling. Interestingly, global Cezanne gene deletion in mice led to smaller atherosclerotic plaques, but with a lower level of plaque stability. Translating, we observed a similar role for Cezanne in human VSMCs, and higher expression levels of Cezanne in human atherosclerotic lesions. CONCLUSION: Cezanne is a key regulator of VSMC proliferation and migration in pathological arterial remodelling. Our findings have important implications for therapeutic targeting Cezanne signalling and VSMC pathology in vascular diseases.

TNF antagonizes CCN1 in apoptosis in esophageal adenocarcinoma.

TNF signaling mostly supports cell growth by activating NFκB and only induces cell death when NFκB activation fails. CCN1 is a matricellular protein that has been reported capable to convert TNF from a pro-survival factor into a stimulus for cell death without interfering with NFκB signaling. In this study, we examined the relationship between CCN1 and TNF in the context of esophageal adenocarcinoma and found that CCN1 did not help TNF to induce cell death when they were together, instead, it inhibited TNF expression, as well as TNF-induced JNK activation and apoptosis. CCN1 induced apoptosis in the cancer cells by itself through upregulation of TRAIL and its death receptors. The presence of TNF significantly lowered CCN1 expression and its capability in apoptosis induction. Furthermore, we found that CCN1 boosted ADAM17-mediated cleavage of TNF receptors through ITGA11 and the soluble decoy receptors generated by this action neutralized TNF activity. Taken together, CCN1 and TNF antagonize each other in esophageal cancer cells.

Circular RNA hsa_circ_0103552 Promotes Proliferation, Migration, and Invasion of Breast Cancer Cells through Upregulating Cysteine-Rich Angiogenic Inducer 61 (CYR61) Expression via Sponging MicroRNA-515-5p.

Circular RNAs (circRNAs) exert a significant regulatory function on tumor progression. This work intends to probe into the biological function and regulatory mechanism of circRNA_0103552 (circ_0103552) in breast cancer carcinogenesis. In this study, circ_0103552, microRNA-515-5p (miR-515-5p), and cysteine-rich angiogenic inducer 61 (CYR61) mRNA expressions in breast cancer cells and tissues were determined by quantitative real-time polymerase chain reaction, followed by cell counting kit 8 and Transwell experiments to examine the multiplication, migration, and invasion of breast cancer cells. Circular RNA Interactome database and StarBase database were searched, and dual-luciferase reporter gene experiments were applied to verify the targeting relationship between circ_0103552 and miR-515-5p, and between miR-515-5p and CYR61, and Western blot was adopted to the regulatory function of circ_0103552 and miR-515-5p on CYR61 protein expression. Circ_0103552 expression was found to be remarkably up-modulated in breast cancer tissues and cells, and circ_0103552 overexpression facilitated the multiplication, migration, and invasion of breast cancer cells, while knocking down circ_0103552 induced the opposite effects. Mechanistically, circ_0103552 could sponge miR-515-5p and restrained its expression in breast cancer cells. MiR-515-5p could counteract the functions of circ_0103552 in breast cancer cells. Additionally, CYR61 was revealed to be a downstream target of miR-515-5p in breast cancer cells. In summary, this study shows that circ_0103552 up-modulates CYR61 expression by targeting miR-515-5p and thus facilitates the multiplication, migration, and invasion of breast cancer cells.

CCN1 gene polymorphisms associated with congenital heart disease susceptibility in Northwest Chinese population from different high-altitude areas.

High-altitude hypoxic environment exposure is considered one of the risk factors for congenital heart disease (CHD), but the genetic factors involved are still unclear. CCN1, one of the synergistic molecules in the hypoxic response, is also an indispensable molecule in cardiac development. Considering that CCN1 may play an important role in the occurrence of CHD in high-altitude areas, we investigated the association between CCN1 polymorphisms and CHD susceptibility in Northwest Chinese population from different high-altitude areas. We conducted a case-control study with a total of 395 CHD cases and 486 controls to evaluate the associations of CCN1 polymorphisms with CHD risk. Our results showed that the protective alleles rs3753793-C (OR = 0.59, 95% CI = 0.42-0.81, P = 0.001), rs2297141-A (OR = 0.66, 95% CI = 0.49-0.90, P = 0.001), and C-A haplotype of rs3753793-rs2297141 (OR = 0.58, 95% CI = 0.42-0.82, P = 0.002) were significantly associated with a decreased atrial septal defect (ASD) risk. Further subgroup analysis in different geography populations revealed robust association of SNP rs2297141 with ASD risk in a Han population residing in high altitude of 2500-4287 m. We also found that the frequency of protective alleles was higher in high-altitude population, and the alleles were responsible for the difference of oxygen physiology-related erythrocyte parameters in different high-altitude populations. rs3753793-C and rs2297141-A are likely related to high altitude and hypoxia adaptation, which may also be the reason for the association between CCN1 polymorphism and ASD risk.

NR4A1 knockdown confers hepatoprotection against ischaemia-reperfusion injury by suppressing TGFß1 via inhibition of CYR61/NF-κB in mouse hepatocytes.

Nuclear receptor subfamily 4, group A, member 1 (NR4A1) can aggravate ischaemia-reperfusion (I/R) injury in the heart, kidney and brain. Thus, the present study aimed to unravel the role of NR4A1 on hepatic I/R injury. For this purpose, the mouse hepatic I/R model and H/R-exposed mouse hepatocytes model were established to stimulate the hepatic and hepatocellular damage. Then, the levels of ALT and AST as well as TNF-α and IL-1ß expression were measured in the mouse serum and supernatant of hepatocyte s, respectively. Thereafter, we quantified the levels of NR4A1, CYR61, NF-kB p65 and TGFß1 under pathological conditions, and their interactions were analysed using ChIP and dual-luciferase reporter gene assays. The in vivo and in vitro effects of NR4A1, CYR61, NF-kB p65 and TGFß1 on I/R-induced hepatic and H/R-induced hepatocellular damage were evaluated using gain- and loss-of-function approaches. NR4A1 was up-regulated in the hepatic tissues of I/R-operated mice and in H/R-treated hepatocytes. Silencing NR4A1 relieved the I/R-induced hepatic injury, as supported by suppression of ALT and AST as well as TNF-α and IL-1ß. Meanwhile, NR4A1 knockdown attenuated the H/R-induced hepatocellular damage by inhibiting the apoptosis of hepatocyte s. Moreover, we also found that NR4A1 up-regulated the expression of CYR61 which resulted in the activation of the NF-κB signalling pathway, thereby enhancing the transcription of TGFß1, which was validated to be the mechanism underlying the contributory role of NR4A1 in hepatic I/R injury. Taken together, NR4A1 silencing reduced the expression of CYR61/NF-κB/TGFß1, thereby relieving the hepatic I/R injury.

Association between CCN1 gene polymorphism and acute coronary syndrome in Chinese Han and Uygur populations.

BACKGROUND: CCN1 plays a crucial role in the modulation of cardiovascular diseases. However, whether CCN1 genetic variants are involved in the susceptibility of ACS remains unknown. Hence, the present study investigates the association between CCN1 polymorphisms and ACS among Han and Uygur populations in Xinjiang, China. RESULTS: In this case-control study, 1234 Han (547 ACS patients and 687 controls) and 932 Uygur (471 ACS patients and 461 controls) were genotyped using SNPscanTM for three single-nucleotide polymorphisms (SNPs, rs6576776, rs954353, and rs3753794) of the human CCN1 gene. In the Uygur population, we found that the detected frequencies of the C allele (25.3% vs. 18.3%, P<0.001) and CC genotype (6.4% vs. 3.0%, P=0.001) of rs6576776 were significantly higher in the ACS patients than in the control participants. Differences in rs6576776 regarding the dominant model (CC+CG vs. GG, 44.2% vs. 55.8%, P=0.001) and the recessive model (CC vs. CG+GG, 6.4% vs. 93.6%, P=0.016) were observed between the two groups. The frequencies of the GGC and AGC haplotypes in those with ACS were significantly higher than those in the control group (all P<0.05) in the Uygur population. After adjusting for hypertension, diabetes, lipids and smoking, all of which indicate that the rs6576776 C allele is associated with higher risk of ACS (odds ratio (OR)=1.798, 95% confidence interval (CI), 1.218-2.656, P=0.003). In Han population, neither the distribution of genotypes and alleles of the CCN1 gene three SNPs nor the distribution of haplotypes constructed with the three SNPs exhibited a significant difference between the ACS patients and control participants. CONCLUSIONS: Our study document that the CCN1 gene rs6576776 C allele is associated with higher susceptibility of ACS and that the frequencies of GGC and AGC haplotypes are higher among the Uygur ACS patients.

MiR-181b suppresses angiogenesis by directly targeting cellular communication network factor 1.

Angiogenesis is essential for various physiological and pathological processes. Previous studies have shown that miRNAs play an important role in blood vessel development and angiogenesis. Recent studies have suggested that miR-181b might be involved in the regulation of angiogenesis in tumors. However, whether miR-181b plays a role in angiogenesis in nontumor diseases is unclear. We found that miR-181b expression was downregulated in hypoxia-stimulated primary human umbilical vein endothelial cells (HUVECs) and a mouse hindlimb ischemia (HLI) model. Gain- and loss-of-function studies showed that a miR-181b mimic inhibited HUVEC migration and tube formation in vitro, and a miR-181b inhibitor had the opposite effects. In vivo, agomir-181b suppressed perfusion recovery in the HLI model and capillary density in a Matrigel plug assay, while perfusion recovery and capillary density were increased by injection of antagomir-181b. Mechanistically, we showed with a reporter assay that cellular communication network factor 1 (CCN1) was a direct target of miR-181b. Moreover, miR-181b suppressed angiogenesis at least in part by targeting CCN1 to inhibit the AMPK signaling pathway. Our research suggests that miR-181b suppresses angiogenesis by directly targeting CCN1, which provides new clues for pro-angiogenic treatment strategies.

Induction of CCN1 in Growing Saccular Aneurysms: A Potential Marker Predicting Unstable Lesions.

Growing evidence has suggested that inflammatory responses promote the progression of saccular intracranial aneurysms (IAs). However, a biomarker predicting the progression has yet to be established. This study aimed to identify novel molecules upregulated during the progression using a previously established rat aneurysm model. In this model, aneurysms are induced at the surgically created common carotid artery (CCA) bifurcation. Based on sequential morphological data, the observation periods after the surgical manipulations were defined as the growing phase (on the 10th day) or the stable phase (on the 30th day). Total cell lysates from the CCA with or without an aneurysm lesion were prepared to perform protein array analysis. The protein array analysis revealed that the matricellular protein cellular communication network factor 1 (CCN1) is induced in lesions during the growing phase. Immunohistochemistry corroborated the significant upregulation of CCN1 in the growing phase compared with the stable phase. Simultaneously with the induction of CCN1, significant increases in the number of CD68-positive macrophages, myeloperoxidase-positive cells, and proliferating smooth muscle cells in lesions were observed. Immunohistochemistry of human IA specimens reproduced the induction of CCN1 in some lesions. These findings imply a potential role of CCN1 as a marker predicting the progression of saccular aneurysms.

Cyr61 promotes Schwann cell proliferation and migration via αvß3 integrin.

BACKGROUND: Schwann cells (SCs) play a crucial role in the repair of peripheral nerves. This is due to their ability to proliferate, migrate, and provide trophic support to axon regrowth. During peripheral nerve injury, SCs de-differentiate and reprogram to gain the ability to repair nerves. Cysteine-rich 61 (Cyr61/CCN1) is a member of the CCN family of matrix cell proteins and have been reported to be abundant in the secretome of repair mediating SCs. In this study we investigate the function of Cyr61 in SCs. RESULTS: We observed Cyr61 was expressed both in vivo and in vitro. The promoting effect of Cyr61 on SC proliferation and migration was through autocrine and paracrine mechanisms. SCs expressed αvß3 integrin and the effect of Cyr61 on SC proliferation and migration could be blocked via αvß3 integrin. Cyr61 could influence c-Jun protein expression in cultured SCs. CONCLUSIONS: In this study, we found that Cyr61 promotes SC proliferation and migration via αvß3 integrin and regulates c-Jun expression. Our study contributes to the understanding of cellular and molecular mechanisms underlying SC's function during nerve injury, and thus, may facilitate the regeneration of peripheral nerves after injury.

Seven Novel Genes Related to Cell Proliferation and Migration of VHL-Mutated Pheochromocytoma.

Pheochromocytoma, as a neuroendocrine tumor with the highest genetic correlation in all types of tumors, has attracted extensive attention. Von Hipper Lindau (VHL) has the highest mutation frequency among the genes associated with pheochromocytoma. However, the effect of VHL on the proteome of pheochromocytoma remains to be explored. In this study, the VHL knockdown (VHL-KD) PC12 cell model was established by RNA interference (shRNA). We compared the proteomics of VHL-KD and VHL-WT PC12 cell lines. The results showed that the expression of 434 proteins (VHL shRNA/WT > 1.3) changed significantly in VHL-KD-PC12 cells. Among the 434 kinds of proteins, 83 were involved in cell proliferation, cell cycle and cell migration, and so on. More importantly, among these proteins, we found seven novel key genes, including Connective Tissue Growth Factor (CTGF), Syndecan Binding Protein (SDCBP), Cysteine Rich Protein 61 (CYR61/CCN1), Collagen Type III Alpha 1 Chain (COL3A1), Collagen Type I Alpha 1 Chain (COL1A1), Collagen Type V Alpha 2 Chain (COL5A2), and Serpin Family E Member 1 (SERPINE1), were overexpressed and simultaneously regulated cell proliferation and migration in VHL-KD PC12 cells. Furthermore, the abnormal accumulation of HIF2α caused by VHL-KD significantly increased the expression of these seven genes during hypoxia. Moreover, cell-counting, scratch, and transwell assays demonstrated that VHL-KD could promote cell proliferation and migration, and changed cell morphology. These findings indicated that inhibition of VHL expression could promote the development of pheochromocytoma by activating the expression of cell proliferation and migration associated genes.