MicroRNA-454 regulates stromal cell derived factor-1 in the control of the growth of pancreatic ductal adenocarcinoma

SDF-1 and NOTCH signaling in myogenic cell differentiation: the role of miRNA10a, 425, and 5100

BACKGROUND

Skeletal muscle regeneration is a complex process regulated by many cytokines and growth factors. Among the important signaling pathways regulating the myogenic cell identity are these involving SDF-1 and NOTCH. SDF-1 participates in cell mobilization and acts as an important chemoattractant. NOTCH, on the other hand, controls cell activation and myogenic determination of satellite cells. Knowledge about the interaction between SDF-1 and NOTCH signaling is limited.

METHODS

We analyzed two populations of myogenic cells isolated from mouse skeletal muscle, that is, myoblasts derived from satellite cells (SCs) and muscle interstitial progenitor cells (MIPCs). First, microRNA level changes in response to SDF-1 treatment were analyzed with next-generation sequencing (NGS). Second, myogenic cells, i.e., SC-derived myoblasts and MIPCs were transfected with miRNA mimics, selected on the basis of NGS results, or their inhibitors. Transcriptional changes, as well as proliferation, migration, and differentiation abilities of SC-derived myoblasts and MIPCs, were analyzed in vitro. Naive myogenic potential was assessed in vivo, using subcutaneous engrafts and analysis of cell contribution to regeneration of the skeletal muscles.

RESULTS

SDF-1 treatment led to down-regulation of miR10a, miR151, miR425, and miR5100 in myoblasts. Interestingly, miR10a, miR425, and miR5100 regulated the expression of factors involved in the NOTCH signaling pathway, including Dll1, Jag2, and NICD. Furthermore, miR10a, miR425, and miR5100 down-regulated the expression of factors involved in cell migration: Acta1, MMP12, and FAK, myogenic differentiation: Pax7, Myf5, Myod, Mef2c, Myog, Musk, and Myh3. However, these changes did not significantly affect myogenic cell migration or fusion either in vitro or in vivo, except when miR425 was overexpressed, or miR5100 inhibitor was used. These two molecules increased the fusion of MIPCs and myoblasts, respectively. Furthermore, miR425-transfected MIPC transplantation into injured skeletal muscle resulted in more efficient regeneration, compared to control cell transplantation. However, skeletal muscles that were injected with miR10a transfected myoblasts regenerated less efficiently.

CONCLUSIONS

SDF-1 down-regulates miR10a, miR425, and miR5100, what could affect NOTCH signaling, differentiation of myogenic cells, and their participation in skeletal muscle regeneration.

microRNAs Associated with Gemcitabine Resistance via EMT, TME, and Drug Metabolism in Pancreatic Cancer

Despite extensive research, pancreatic cancer remains a lethal disease with an extremely poor prognosis. The difficulty in early detection and chemoresistance to therapeutic agents are major clinical concerns. To improve prognosis, novel biomarkers, and therapeutic strategies for chemoresistance are urgently needed. microRNAs (miRNAs) play important roles in the development, progression, and metastasis of several cancers. During the last few decades, the association between pancreatic cancer and miRNAs has been extensively elucidated, with several miRNAs found to be correlated with patient prognosis. Moreover, recent evidence has revealed that miRNAs are intimately involved in gemcitabine sensitivity and resistance through epithelial-to-mesenchymal transition, the tumor microenvironment, and drug metabolism. Gemcitabine is the gold standard drug for pancreatic cancer treatment, but gemcitabine resistance develops easily after chemotherapy initiation. Therefore, in this review, we summarize the gemcitabine resistance mechanisms associated with aberrantly expressed miRNAs in pancreatic cancer, especially focusing on the mechanisms associated with epithelial-to-mesenchymal transition, the tumor microenvironment, and metabolism. This novel evidence of gemcitabine resistance will drive further research to elucidate the mechanisms of chemoresistance and improve patient outcomes.

Interplays between non-coding RNAs and chemokines in digestive system cancers

Within tumors, chemokines and their cognate receptors are expressed by infiltrated leukocytes, cancerous cells, and related cells of stroma, like tumor-associated fibroblasts and tumor-associated macrophages. In malignancies, the altered expression of chemokines/chemokine receptors governs leukocyte infiltration and activation, epithelial-mesenchymal transition (EMT), cancer cell proliferation, angiogenesis, and metastasis. Non-coding RNAs (ncRNAs) contribute to multiple physiological and pathophysiological processes. Some miRNAs can exert anti-tumorigenic activity in digestive system malignancies by repressing the expression of tumor-promoting chemokines/chemokine receptors or by upregulating tumor-suppressing chemokines/chemokine receptors. However, many miRNAs exert pro-tumorigenic activity by suppressing the expression of chemokines/chemokine receptors or by upregulating tumor-promoting chemokines/chemokine receptors. LncRNA and circRNAs also exert pro- and anti-tumorigenic effects by targeting downstream miRNAs influencing the expression of tumor-promoting and tumor-suppressor chemokines/chemokine receptors. On the other side, some chemokines influence the expression of ncRNAs affecting tumor formation. The current review explains the communications between ncRNAs and chemokines/chemokine receptors in certain digestive system malignancies, such as gastric, colorectal, and pancreatic cancers and hepatocellular carcinoma to gain better insights into their basic crosstalk as well as possible therapeutic modalities.

Overexpression of microRNA-345 Affects the Invasive Capacity of Pancreatic Ductal Adenocarcinoma Cell Lines by Suppressing MUC1 and TJP2 Expression

The majority of pancreatic carcinomas are pancreatic ductal adenocarcinomas (PDAC), and the presence of non-invasive pancreatic intraepithelial neoplasia or intraductal papillary mucinous neoplasm, as an associated lesion, is considered important. These microscopic hyperplastic or grossly papillomatous lesions exhibit varying degrees of morphological atypia and may develop into invasive carcinomas. In this study, we investigated whether mucin-1 (MUC1) is involved in the progression of pancreatic carcinoma and examined the mechanisms by which microRNAs regulate MUC1 expression in vitro. In PDAC cell lines, suppression of MUC1 expression reduced cell proliferation and invasion; PDAC cell lines transfected with an miR-345 precursor suppressed the expression of MUC1, and reduced cell proliferation and invasion. Tight junction protein 2 (TJP2), a putative target of miR-345, is regulated by MUC1. The suppression of TJP2 expression reduced cell proliferation by inducing apoptosis. These results suggest that MUC1 and TJP2, the putative target molecules of miR-345, are critical in maintaining the invasive potential of pancreatic carcinoma cells, and regulating their expression may prevent the progression of non-invasive pancreatic intraductal lesions to invasive carcinomas. This study provides new insights for the development of novel molecular targeted therapies for pancreatic carcinomas.

Role of non-coding RNAs in tumor progression and metastasis in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer with an overall 5-year survival rate of less than 10%. The 1-year survival rate of patients with locally advanced or metastatic disease is abysmal. The aggressive nature of cancer cells, hypovascularization, extensive desmoplastic stroma, and immunosuppressive tumor microenvironment (TME) endows PDAC tumors with multiple mechanisms of drug resistance. With no obvious genetic mutation(s) driving tumor progression or metastatic transition, the challenges for understanding the biological mechanism(s) of these processes are paramount. A better understanding of the molecular and cellular mechanisms of these processes could lead to new diagnostic tools for patient management and new targets for therapeutic intervention. microRNAs (miRNAs) are an evolutionarily conserved gene class of short non-coding regulatory RNAs. miRNAs are an extensive regulatory layer that controls gene expression at the posttranscriptional level. This review focuses on preclinical models that functionally dissect miRNA activity in tumor progression or metastatic processes in PDAC. Collectively, these studies suggest an influence of miRNAs and RNA-RNA networks in the processes of epithelial to mesenchymal cell transition and cancer cell stemness. At a cell-type level, some miRNAs mainly influence cancer cell–intrinsic processes and pathways, whereas other miRNAs predominantly act in distinct cellular compartments of the TME to regulate fibroblast and immune cell functions and/or influence other cell types’ function via cell-to-cell communications by transfer of extracellular vesicles. At a molecular level, the influence of miRNA-mediated regulation often converges in core signaling pathways, including TGF-β, JAK/STAT, PI3K/AKT, and NF-κB.

Modulation of cell physiology under hypoxia in pancreatic cancer

In solid tumors, the development of vasculature is, to some extent, slower than the proliferation of the different types of cells that form the tissue, both cancer and stroma cells. As a consequence, the oxygen availability is compromised and the tissue evolves toward a condition of hypoxia. The presence of hypoxia is variable depending on where the cells are localized, being less extreme at the periphery of the tumor and more severe in areas located deep within the tumor mass. Surprisingly, the cells do not die. Intracellular pathways that are critical for cell fate such as endoplasmic reticulum stress, apoptosis, autophagy, and others are all involved in cellular responses to the low oxygen availability and are orchestrated by hypoxia-inducible factor. Oxidative stress and inflammation are critical conditions that develop under hypoxia. Together with changes in cellular bioenergetics, all contribute to cell survival. Moreover, cell-to-cell interaction is established within the tumor such that cancer cells and the microenvironment maintain a bidirectional communication. Additionally, the release of extracellular vesicles, or exosomes, represents short and long loops that can convey important information regarding invasion and metastasis. As a result, the tumor grows and its malignancy increases. Currently, one of the most lethal tumors is pancreatic cancer. This paper reviews the most recent advances in the knowledge of how cells grow in a pancreatic tumor by adapting to hypoxia. Unmasking the physiological processes that help the tumor increase its size and their regulation will be of major relevance for the treatment of this deadly tumor.

Long non-coding RNA SNHG1 stimulates ovarian cancer progression by modulating expression of miR-454 and ZEB1

Ovarian cancer (OC) is highly prevalent and is associated with high mortality rates due to metastasis and relapse. In this study, we assessed the role of long non‐coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) in OC to gain further insight into mechanisms that contribute to its aggressiveness. We analyzed the correlation between SNHG1, miR‐454 and zinc finger E‐box‐binding homeobox 1 (ZEB1) using a dual‐luciferase reporter assay. Alterations in cell metastasis and invasiveness were observed using wound‐healing and Transwell invasion assays, respectively. Tumor xenografts allowed us to monitor liver metastasis of mice injected with A2780 cells. We found that SNHG1 is overexpressed in OC. Downregulation of SNHG1 promoted miR‐454 expression and reduced ZEB1 levels. In addition, knockdown of SNHG1, also reduced the aggressiveness of A2780 and SK‐OV3 cells. Furthermore, SNHG1 downregulation by siRNA hindered cell migration and invasion; however, this effect was reversed by co‐transfection of miR‐454 into A2780 and SK‐OV3 cells. Moreover, SNHG1 increased ZEB1 expression by downregulating miR‐454 and activated Akt signaling, thereby promoting epithelial‐mesenchymal transition and enhancing the invasiveness of OC cells. Tumor xenograft analyses confirmed that SNHG1 affects OC proliferation and metastasis in vivo. In summary, our data demonstrate that SNHG1 plays crucial roles in tumor progression and may be a useful maker for OC prognosis.

The CXCL12 Crossroads in Cancer Stem Cells and Their Niche

Simple Summary

CXCL12 and its receptors have been extensively studied in cancer, including their influence on cancer stem cells (CSCs) and their niche. This intensive research has led to a better understanding of the crosstalk between CXCL12 and CSCs, which has aided in designing several drugs that are currently being tested in clinical trials. However, a comprehensive review has not been published to date. The aim of this review is to provide an overview on how CXCL12 axes are involved in the regulation and maintenance of CSCs, their presence and influence at different cellular levels within the CSC niche, and the current state-of-the-art of therapeutic approaches aimed to target the CXCL12 crossroads.

Abstract

Cancer stem cells (CSCs) are defined as a subpopulation of “stem”-like cells within the tumor with unique characteristics that allow them to maintain tumor growth, escape standard anti-tumor therapies and drive subsequent repopulation of the tumor. This is the result of their intrinsic “stem”-like features and the strong driving influence of the CSC niche, a subcompartment within the tumor microenvironment that includes a diverse group of cells focused on maintaining and supporting the CSC. CXCL12 is a chemokine that plays a crucial role in hematopoietic stem cell support and has been extensively reported to be involved in several cancer-related processes. In this review, we will provide the latest evidence about the interactions between CSC niche-derived CXCL12 and its receptors—CXCR4 and CXCR7—present on CSC populations across different tumor entities. The interactions facilitated by CXCL12/CXCR4/CXCR7 axes seem to be strongly linked to CSC “stem”-like features, tumor progression, and metastasis promotion. Altogether, this suggests a role for CXCL12 and its receptors in the maintenance of CSCs and the components of their niche. Moreover, we will also provide an update of the therapeutic options being currently tested to disrupt the CXCL12 axes in order to target, directly or indirectly, the CSC subpopulation.

TSPAN1 promotes autophagy flux and mediates cooperation between WNT-CTNNB1 signaling and autophagy via the MIR454-FAM83A-TSPAN1 axis in pancreatic cancer

Pancreatic cancer is one of the most aggressive tumors associated with a poor clinical prognosis, weakly effective therapeutic options. Therefore, there is a strong impetus to discover new therapeutic targets in pancreatic cancer. In the present study, we first demonstrated that TSPAN1 is upregulated in pancreatic cancer and that TSPAN1 depletion decreases pancreatic cancer cell proliferation in vitro and in vivo. TSPAN1 expression was correlated with poor overall survival of pancreatic cancer patients. Moreover, we demonstrated that TSPAN1 is a novel positive regulator of macroautophagy/autophagy characterized by decreased LC3-II and SQSTM1/p62 expressions, inhibited puncta formation of GFP-LC3 and autophagic vacuoles. We also demonstrated that tspan1 mutation impaired autophagy in the zebrafish model. Furthermore, we showed that TSPAN1 promoted autophagy maturation via direct binding to LC3 by two conserved LIR motifs. Mutations in the LIR motifs of TSPAN1 resulted in a loss of the ability to induce autophagy and promote pancreatic cancer proliferation. Second, we discovered two conservative TCF/LEF binding elements present in the promoter region of the TSPAN1 gene, which was further verified through luciferase activity and ChIP assays. Furthermore, TSPAN1 was upregulated by FAM83A through the canonical WNT-CTNNB1 signaling pathway. We further demonstrated that both TSPAN1 and FAM83A are both direct targets of MIR454 (microRNA 454). Additionally, we revealed the role of MIR454-FAM83A-TSPAN1 in the proliferation of pancreatic cancer cells in vitro and in vivo. Our findings suggest that components of the MIR454-FAM83A-TSPAN1 axis may be valuable prognosis markers or therapeutic targets for pancreatic cancer.Abbreviations: AMPK: adenosine 5'-monophosphate (AMP)-activated protein kinase; APC: APC regulator of WNT signaling pathway; ATG: autophagy related; AXIN2: axin 2; BECN1: beclin 1; CCND1: cyclin D1; CSNK1A1/CK1α: casein kinase 1 alpha 1; CTNNB1/β-catenin: catenin beta 1; DAPI: 4'6-diamino-2-phenylindole; EBSS: Earle's balanced salt solution; EdU: 5-ethynyl-20-deoxyuridine; FAM83A: family with sequence similarity 83 member A; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; GSEA: gene set enrichment analysis; GSK3B: glycogen synthase kinase 3 beta; IHC: immunohistochemical; LAMP1: lysosomal associated membrane protein 1; LIR: LC3-interacting region; MAP1LC3/LC3, microtubule associated protein 1 light chain 3; MIR454: microRNA 454; miRNA: microRNA; MKI67: antigen identified by monoclonal antibody Ki 67; MTOR: mechanistic target of rapamycin kinase; MTT: 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide; MYC: MYC proto-oncogene, bHLH transcription factor; OS: overall survival; PDAC: pancreatic ductal adenocarcinoma; RAB7A: RAB7A, member RAS oncogene family; shRNA: short hairpin RNA; SQSTM1: sequestosome 1; TBE: TCF/LEF binding element; TCGA: The Cancer Genome Atlas; TCF/LEF: transcription factor/lymphoid enhancer binding factor; TCF4: transcription factor 4; TSPAN1: tetraspanin 1; TUNEL: terminal deoxynucleotidyl transferase mediated dUTP nick end labeling; UTR: untranslated region; WT: wild type.

miR-454 suppresses the proliferation and invasion of ovarian cancer by targeting E2F6

Background

The aberrant expression of microRNA-454 (miR-454) has been confirmed to be involved in the development of cancers. However, the functional role of miR-454 in the progression of ovarian cancer remains unclear.

Methods

The expression of miR-454 in ovarian cancer cells and serum of ovarian cancer patients was detected by RT-PCR. CCK8, colony formation, transwell, and flow cytometry assays were conducted to assess the effects of miR-454 on ovarian cancer cell proliferation, migration, invasion, and apoptosis, respectively. Dual-luciferase reporter assay was used to confirm the targeting relationship between miR-454 and E2F6. The expression pattern of E2F6 in ovarian cancer tissues was detected using immunohistochemistry (IHC) assay. The relative expression of related proteins was examined using western blot analysis.

Results

miR-454 was markedly down-regulated by hypoxia in ovarian cancer cells. Compared with normal samples, the expression of miR-454 was up-regulated in the serum of ovarian cancer patients, and correlated with the clinicopathological stages of ovarian cancer. Next, we found that miR-454 overexpression inhibited the proliferation, migration and invasion of OVCAR3 and SKOV3 cells, as well as promoted apoptosis. In addition, the Akt/mTOR and Wnt/β-catenin signaling pathway were inhibited by miR-454 in ovarian cancer cells. Mechanically, bioinformatic analysis and dual-luciferase reporter assay confirmed that E2F6 was a direct target of miR-454 and negatively regulated by miR-454 in ovarian cancer cells. Moreover, IHC analysis showed that E2F6 was highly expressed in ovarian cancer tissues. Finally, we found that the increasing cell proliferation and migration triggered by E2F6 overexpression were abolished by miR-454 overexpression.

Conclusion

Taken together, these results highlight the role of miR-454 as a tumor suppressor in ovarian cancer cells by targeting E2F6, indicating that miR-454 may be a potential diagnostic biomarker and therapeutic target for ovarian cancer.

MicroRNA-141-3p Negatively Modulates SDF-1 Expression in Age-Dependent Pathophysiology of Human and Murine Bone Marrow Stromal Cells

Stromal cell-derived factor-1 (SDF-1 or CXCL12) is a cytokine secreted by cells including bone marrow stromal cells (BMSCs). SDF-1 plays a vital role in BMSC migration, survival, and differentiation. Our group previously reported the role of SDF-1 in osteogenic differentiation in vitro and bone formation in vivo; however, our understanding of the post-transcriptional regulatory mechanism of SDF-1 remains poor. MicroRNAs are small noncoding RNAs that post-transcriptionally regulate the messenger RNAs (mRNAs) of protein-coding genes. In this study, we aimed to investigate the impact of miR-141-3p on SDF-1 expression in BMSCs and its importance in the aging bone marrow (BM) microenvironment. Our data demonstrated that murine and human BMSCs expressed miR-141-3p that repressed SDF-1 gene expression at the functional level (luciferase reporter assay) by targeting the 3'-untranslated region of mRNA. We also found that transfection of miR-141-3p decreased osteogenic markers in human BMSCs. Our results demonstrate that miR-141-3p expression increases with age, while SDF-1 decreases in both the human and mouse BM niche. Taken together, these results support that miR-141-3p is a novel regulator of SDF-1 in bone cells and plays an important role in the age-dependent pathophysiology of murine and human BM niche.

A Role for the WNT Co-Receptor LRP6 in Pathogenesis and Therapy of Epithelial Cancers

The WNT/β-catenin signaling pathway controls stem and progenitor cell proliferation, survival and differentiation in epithelial tissues. Aberrant stimulation of this pathway is therefore frequently observed in cancers from epithelial origin. For instance, colorectal and hepatic cancers display activating mutations in the CTNNB1 gene encoding β-catenin, or inactivating APC and AXIN gene mutations. However, these mutations are uncommon in breast and pancreatic cancers despite nuclear β-catenin localization, indicative of pathway activation. Notably, the low-density lipoprotein receptor-related protein 6 (LRP6), an indispensable co-receptor for WNT, is frequently overexpressed in colorectal, liver, breast and pancreatic adenocarcinomas in association with increased WNT/β -catenin signaling. Moreover, LRP6 is hyperphosphorylated in KRAS-mutated cells and in patient-derived colorectal tumours. Polymorphisms in the LRP6 gene are also associated with different susceptibility to developing specific types of lung, bladder and colorectal cancers. Additionally, recent observations suggest that LRP6 dysfunction may be involved in carcinogenesis. Indeed, reducing LRP6 expression and/or activity inhibits cancer cell proliferation and delays tumour growth in vivo. This review summarizes current knowledge regarding the biological function and regulation of LRP6 in the development of epithelial cancers—especially colorectal, liver, breast and pancreatic cancers.

MicroRNA-664 targets paired box protein 6 to inhibit the oncogenicity of pancreatic ductal adenocarcinoma

The abnormal expression of microRNAs (miRNAs or miRs) with oncogenic or tumor‑suppressive roles in pancreatic ductal adenocarcinoma (PDAC) has been widely reported in recent years, and these dysregulated miRNAs are implicated in the formation and progression of PDAC. Therefore, an investigation into the functional roles of miRNAs in PDAC may facilitate the identification of effective therapeutic targets. miRNA‑664 (miR‑664) has been found to be aberrantly expressed and to play crucial roles in several human cancer types. However, the expression pattern and functional roles of miR‑664 in the malignant capacity of PDAC have yet to be elucidated. In this study, the results revealed that miR‑664 was clearly downregulated in PDAC tissues and cell lines. The low miR‑664 expression was strongly associated with pathological T stage and lymph node metastasis of the patients with PDAC. Patients with PDAC with a low miR‑664 expression had a poorer overall survival and a worse disease‑free survival than those patients with a high miR‑664 level. Functional experiments suggested that exogenous miR‑664 expression suppressed the growth and metastasis of PDAC cells in vitro, whereas miR‑664 downregulation exerted the opposite effects. In addition, miR‑664 suppressed the tumor growth of PDAC cells in vivo. Mechanistically, paired box protein 6 (PAX6) was identified as a direct target gene of miR‑664 in PDAC cells. Furthermore, PAX6 was upregulated in PDAC tissues, and its upregulation inversely correlated with miR‑664 levels. Moreover, the silencing of PAX6 mimicked the effects of miR‑664 upregulation in PDAC cells, and the recovered expression of PAX6 eliminated the effects of miR‑664 on PDAC cells. Notably, miR‑664 could inhibit the activation of PI3K/Akt pathway in PDAC cells in vitro and in vivo. Cumulatively, these results indicate an important role of the miR‑664/PAX6 pathway in suppressing the aggressiveness of PDAC cells, suggesting that miR‑664 may be an attractive therapeutic target for the treatment of patients with this fatal disease.

MicroRNA-101 Targets CXCL12-Mediated Akt and Snail Signaling Pathways to Inhibit Cellular Proliferation and Invasion in Papillary Thyroid Carcinoma

Escalating evidence suggests that microRNA-101 (miR-101) is implicated in the development and progression of various cancers, including papillary thyroid carcinoma (PTC). However, the biological function and molecular mechanisms of miR-101 in PTC are still unclear. In this study, we demonstrated that miR-101 expression was significantly decreased in PTC tissues and cell lines. Clinically, a low level of miR-101 was positively associated with advanced histological stages and lymph node and distant metastases. The expression of CXCL12 was negatively correlated with miR-101 level in PTC. CXCL12 was validated as a direct target of miR-101 in PTC cells. Functional experiments proved that miR-101 markedly reduced the proliferation, apoptosis escape, migration, and invasion of PTC cells. Moreover, CXCL12 restoration rescued the suppressive effects of miR-101 on PTC cells by activating Akt- and EMT-associated signaling pathways. Overall, miR-101 exerts oncostatic effects on PTC by downregulating CXCL12 and repressing its downstream Akt and Snail signaling pathways, suggesting that miR-101/CXCL12/Akt or Snail axis may serve as a potential therapeutic target for PTC.

Characterization and Validation of Antibodies for Immunohistochemical Staining of the Chemokine CXCL12

Chemokines and their receptors have been implicated in cancer biology. The CXCL12/CXCR4 axis is essential for the homing and retention of hematopoietic stem cells in bone marrow niches, and has a significant role in neonatal development. It is also implicated in multiple facets of cancer biology including metastasis, angiogenesis/neo-vasculogenesis, and immune cell trafficking at the tumor microenvironment (TME). Immunohistochemistry (IHC) is an ideal method for investigating involvement of CXCL12 in the TME. Three antibodies were evaluated here for their suitability to stain CXCL12. Both D8G6H and K15C gave apparent specific staining in both lymphoid and tumor tissue, but with converse staining patterns. D8G6H stained cells in the parafollicular zone whereas K15C showed staining of lymphoid cells in the interfollicular zone of tonsil tissue. Using a cell line with high CXCL12 expression, TOV21G, as a positive control, it was found that D8G6H gave strong staining of TOV21G cells whereas no staining was observed with K15C indicating that D8G6H specifically stains CXCL12. Significant staining of CXCL12 in the ovarian TME using tissue microarray was observed using D8G6H. These data demonstrate the importance of antibody characterization for IHC applications, and provide further evidence for the involvement of CXCL12 in ovarian cancer biology.

MicroRNA-342 inhibits tumor growth via targeting chemokine CXCL12 involved in macrophages recruitment/activation

MicroRNAs (miRNAs) play important roles in initiation, development, progression and metastasis of tumors. MiR-342 has been reported as a tumor suppressor or an onco-miRNA based on functions or expression changes in various types of cancers. However, the biological roles and underlying molecular mechanisms of miR-342 in tumorigenesis remain largely unknown. Here, we found that miR-342 was expressed significantly less in a murine MS-K tumor cell line that showed riched blood vessels. Over-expression of miR-342 in MS-K cells inhibited cell proliferation, colony formation, reduced frequency of S phase population in vitro and suppressed tumor growth in vivo. Moreover, increasing miR-342 impeded blood vessels formation and accumulation of macrophages (CD11b⁺ ) in tumors. By bioinformatic analysis and dual-luciferase reporter assays, chemokine CXCL12 was identified as a direct target of miR-342. Restored Cxcl12 expression in MS-K-miR-342 cells could rescue cell proliferation in vitro. In MS-K-miR-342 tumor-infiltrated macrophages, expression of proangiogenic genes (Vegf-A and Thbs1) and M2-subtype macrophage markers (Cd163, Dectin1 and Ym1) was significantly down-regulated compared with controls. Moreover, lower level of Cxcl12 and its receptor Cxcr4 was observed in the macrophages of MS-K-miR-342 tumors, and MS-K-miR-342 derived miR-342, but not endogenous miR-342, might contribute to Cxcl12 suppression in TAM. These results suggest that miR-342 is involved in MS-K tumor growth as a tumor suppressor by targeting chemokine CXCL12.

miR-454-3p Is an Exosomal Biomarker and Functions as a Tumor Suppressor in Glioma

Glioma is the most common type of primary malignant brain tumor in adults. Our previous work discovered that plasma miR-454-3p may have some advantages in glioma prognosis, but the clinical significance and the regulatory mechanism of miR-454-3p in glioma have not been systematically investigated, especially regarding the relationship between circulating and tissue miR-454-3p. The expression level of miR-454-3p in glioma serum and tissues was analyzed through quantitative real-time PCR (qRT-PCR). Cell-Counting Kit 8 (CCK-8), wound healing, transwell invasion, apoptosis, and immunofluorescence assays were used to assess the role of miR-454-3p in glioma cancer cells. ATG12 was selected as the target gene of miR-454-3p by bioinformatic analysis. The relationship between ATG12 and miR-454-3p was further validated by luciferase reporter assays and Western blot analysis. miR-454-3p was significantly downregulated in tumor tissues, while it was remarkably upregulated in exosomes from the same patients with glioma. The area under curve (AUC) of exosomal miR-454-3p for glioma diagnosis was 0.8663. The exosomal miR-454-3p was prominently lower in the postoperative serums than that in the preoperative serums. High miR-454-3p expression in exosomes or low miR-454-3p expression in tissue was associated with poor prognosis. Restored expression of miR-454-3p suppressed cell proliferation, migration, invasion, and autophagy in glioma. ATG12 was validated as a direct target of miR-454-3p. The overexpression of ATG12 could partially reverse the effects induced by miR-454-3p suppression. Our data indicate that miR-454-3p may serve as an exosomal biomarker and may be developed into a novel treatment for glioma.

MicroRNA-454 contributes to sustaining the proliferation and invasion of trophoblast cells through inhibiting Nodal/ALK7 signaling in pre-eclampsia

MicroRNAs (miRNAs) are emerging as important regulators in the pathogenesis of pre-eclampsia (PE). Recent evidence has reported that miR-454 plays an important role in regulating cell proliferation and invasion. The decreased proliferation and invasion of trophoblast cells contribute to the pathogenesis of PE. However, whether miR-454 is involved in the regulation of trophoblast cell proliferation and invasion remains unknown. In this study, we aimed to investigate the potential role and underlying mechanism of miR-454 in regulating trophoblast cell proliferation and invasion in vitro. We found that miR-454 expression was significantly decreased in placental tissues from PE patients compared to controls. Transfection of miR-454 mimics promoted the proliferation, reduced the apoptosis, and increased invasion of trophoblast cells, while transfection of miR-454 inhibitor showed opposite effects. Bioinformatics analysis showed that activin receptor-like kinase 7 (ALK7) was a potential target gene of miR-454. Dual-luciferase reporter assay showed miR-454 directly targeted the 3'-untranslated region of AKL7. Further experiments showed that miR-454 negatively regulated ALK7 expression. Interestingly, transfection of miR-454 mimics significantly abrogated the inhibitory effect of Nodal on trophoblast cell proliferation and invasion. Moreover, overexpression of ALK7 markedly reversed the promotion effect of miR-454 on trophoblast cell proliferation and invasion. Overall, our results suggest that miR-454 promotes the proliferation and invasion of trophoblast cells by downregulation of ALK7. Our study suggests that miR-454 may play critical roles in the pathogenesis of PE and serve as a potential therapeutic target for treatment of PE.

MicroRNA-661 expression is upregulated in pancreatic ductal adenocarcinoma and promotes cell proliferation

Deregulation of microRNA (miRNA/miR) expression has been implicated in the development of pancreatic ductal adenocarcinoma (PDAC). However, the role of miR-661 in PDAC remains unknown. In the present study, it was revealed that miR-661 expression was significantly upregulated in PDAC tissues compared with that in adjacent normal tissues by using reverse transcription-quantitative polymerase chain reaction assays. Higher miR-661 expression revealed a positive association with lymph node metastasis, an advanced T stage and a poor prognosis in patients with PDAC. Furthermore, ectopic expression of miR-661 significantly promoted the cell proliferation ability in PDAC cell lines, and simultaneously promoted Wnt signaling pathway-related protein expression of β-catenin, transcription factor 4 and cyclin D1 in vitro. However, the downregulation of miR-661 revealed reverse effects. Thus, the results of the present study indicated that miR-661 may function as a prognostic marker and provide insight for pancreatic cancer treatment.

miR‑454‑3p suppresses cell migration and invasion by targeting CPEB1 in human glioblastoma

MicroRNAs (miRNA/miRs) serve crucial roles in the progression of human glioblastoma (GBM); however, the exact regulatory mechanisms of miRNAs in human GBM remain unclear. The present study aimed to investigate the roles of miR‑454‑3p in human GBM. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis was performed to examine the expression of miR‑454‑3p in glioma tissues and adjacent tissues. Human GBM cell lines (LN‑229, A172 and GL15) and a normal human astrocyte cells (HA1800) were used for analysis. In addition, RT‑qPCR and western blotting were applied for mRNA and protein expression analysis, respectively. The cell proliferation was measured using a Cell Counting kit‑8 assay. Furthermore, scratch and Transwell assays were employed for the analysis of cell migration and invasion. A luciferase reporter assay was used to verify the target of miR‑454‑3p. The results revealed that miR‑454‑3p was downregulated in the glioma tissues and GBM cell lines, including LN‑229, A172 and GL15. Additionally, the overexpression of miR‑454‑3p significantly suppressed the proliferation, migration and invasion of LN‑229 cells. Furthermore, cytoplasmic polyadenylation element‑binding protein 1 (CPEB1) was confirmed as a direct target of miR‑454‑3p. These findings indicated that the overexpression of miR‑454‑3p inhibited cell proliferation, migration and invasion by downregulating CPEB1. Therefore, miR‑454‑3p may act as a tumor suppressor and represent an effective therapeutic strategy in GBM.

gga-miR-454 suppresses infectious bursal disease virus (IBDV) replication via directly targeting IBDV genomic segment B and cellular Suppressors of Cytokine Signaling 6 (SOCS6)

MicroRNAs (miRNAs), as post-transcriptional regulators, play important roles in the process of viral infection through inhibiting virus replication or modulating host immune response. However, the role of miRNAs in host response against infectious bursal disease virus (IBDV) infection is still unclear. In this study, we found that gga-miR-454 of the host was decreased in response to IBDV infection and that transfection of DF-1 cells with miR-454 inhibited IBDV replication via directly targeting the specific sequence of IBDV genomic segment B, while blockage of endogenous miR-454 by inhibitors enhanced virus replication. Furthermore, gga-miR-454 increased the expression of IFN-β by targeting Suppressors of Cytokine Signaling 6 (SOCS6), enhancing the antiviral response of host cells. These findings highlight a crucial role of gga-miR-454 in host defense against IBDV infection.

MicroRNA-454 inhibits non‑small cell lung cancer cells growth and metastasis via targeting signal transducer and activator of transcription-3

Lung cancer is one of the most common type of cancers and the leading cause of cancer‑related mortality worldwide. Non-small cell lung cancer (NSCLC) accounts for >80% of lung cancer cases. Emerging studies have suggested that microRNAs are dysregulated in NSCLC and serve important roles in NSCLC initiation and development. However, to the best of our knowledge, the expression, roles and molecular mechanism of microRNA‑454 (miR‑454) have not been investigated in NSCLC. In the present study, miR‑454 was demonstrated to be significantly downregulated in NSCLC tissues and cell lines, as assessed by western blot analysis and reverse transcription‑quantitative polymerase chain reaction. Reduced miR‑454 expression was significantly correlated with aggressive clinicopathological features in NSCLC. In addition, upregulation of miR‑454 suppressed proliferation, migration and invasion NSCLC cells, as assessed by Cell Counting Kit‑8 and in vitro migration and invasion assays, respectively. Furthermore, bioinformatics analysis identified STAT3 as a direct target gene of miR‑454, and STAT3 knockdown was demonstrated to simulate the effects of miR‑454 overexpression in NSCLC. In conclusion, the present study provided convincing evidence that miR‑454 is downregulated in NSCLC, and regulates growth and metastasis by directly targeting STAT3, which suggests that miR‑454 may be an efficient therapeutic target for NSCLC.

Functions of pancreatic stellate cell-derived soluble factors in the microenvironment of pancreatic ductal carcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal forms of cancer with poor prognosis because it is highly resistant to traditional chemotherapy and radiotherapy and it has a low rate of surgical resection eligibility. Pancreatic stellate cells (PSC) have become a research hotspot in recent years, and play a vital role in PDAC microenvironment by secreting soluble factors such as transforming growth factor β, interleukin-6, stromal cell-derived factor-1, hepatocyte growth factor and galectin-1. These PSC-derived cytokines and proteins contribute to PSC activation, participating in PDAC cell proliferation, migration, fibrosis, angiogenesis, immunosuppression, epithelial-mesenchymal transition, and chemoradiation resistance, leading to malignant outcome. Consequently, targeting these cytokines and proteins or their downstream signaling pathways is promising for treating PDAC.

Suppression of microRNA-454 impedes the proliferation and invasion of prostate cancer cells by promoting N-myc downstream-regulated gene 2 and inhibiting WNT/β-catenin signaling

MicroRNA-454 (miR-454) is emerging as critical regulator in tumorigenesis; it may function as an oncogene or a tumor suppressor. However, the role of miR-454 in prostate cancer remains unknown. In this study, we aimed to investigate the function and molecular mechanisms of miR-454 in prostate cancer. We found that miR-454 was highly expressed in prostate cancer tissues and cell lines (*p<0.05), as detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell counting kit-8 assay, colony formation assay and cell invasion assay showed that the inhibition of miR-454 significantly suppressed prostate cancer cell proliferation and invasion (*p<0.05), whereas the overexpression of miR-454 markedly promoted prostate cancer cell proliferation and invasion (*p<0.05). Bioinformatics analysis showed that N-myc downstream-regulated gene 2 (NDRG2), a well-known tumor suppressor, was identified as a potential target gene of miR-454. Dual-luciferase reporter assay showed that miR-454 directly targeted the 3'-untranslated region of NDRG2. RT-qPCR and western blot showed that miR-454 overexpression significantly decreased NDRG2 expression (*p<0.05), whereas miR-454 inhibition markedly promoted NDRG2 expression (*p<0.05). Spearman's correlation analysis showed that miR-454 expression was inversely correlated with NDRG2 expression in prostate cancer tissues (r=-0.8932; p<0.0001). Moreover, miR-454 inhibition significantly suppressed the protein expression of β-catenin (*p<0.05) and blocked the activation of WNT signaling (*p<0.05). In addition, small interfering RNA mediated NDRG2 knockdown significantly reversed the antitumor effect of miR-454 inhibition on prostate cancer cell proliferation and invasion (*p<0.05). Taken together, these results reveal an oncogenic role of miR-454, which promotes prostate cancer cell proliferation and invasion by downregulation of NDRG2. These results also suggest miR-454 as a potential therapeutic target for the treatment of prostate cancer.

microRNA-454 shows anti-angiogenic and anti-metastatic activity in pancreatic ductal adenocarcinoma by targeting LRP6

Our previous work has shown that microRNA-454 (miR-454) can inhibit the growth of pancreatic ductal adenocarcinoma (PDAC) by blocking the recruitment of bone marrow-derived macrophages. In the present study, we aimed to explore its role in the proliferation, invasion, and pro-angiogenic activity of PDAC cells in vitro and lung metastasis in vivo. PANC-1 and MiaPaCa-2 cells were transfected with a miR-454-expressing plasmid and tested for cell proliferation, colony formation, cell cycle distribution, invasion, and pro-angiogenic activity. The target gene(s) that mediated the action of miR-454 was identified. The effect of miR-454 overexpression on lung metastasis of PDAC was evaluated in nude mice. Of note, overexpression of miR-454 significantly inhibited PDAC cell proliferation and colony formation and arrests PDAC cells at the G2/M phase. Decreased invasiveness was observed in miR-454-overexpressing PDAC cells. Conditioned media from miR-454-overexpressing PANC-1 cells contained lower levels of vascular endothelial growth factor and had reduced capacity to induce endothelial cell tube-like structure formation. Mechanistically, miR-454 was found to target the mRNA of LRP6 and inhibit the activation of Wnt/β-catenin signaling in PDAC cells. Ectopic expression of LRP6 significantly reversed the suppressive effects of miR-454 on PDAC cells. In vivo studies confirmed that miR-454-overexpressing PANC-1 cells formed significantly less lung metastases than control cells. Altogether, miR-454 functions as a suppressor in tumor growth, angiogenesis, and metastasis in PDAC, likely through downregulation of LRP6.

Combined thermosensitive in situ gel with AMD3100 in sutureless technique improves the survival and function of kidney transplants in mice

The mouse is an optimal animal model for kidney transplantation. Recent reports suggest that application of poloxamer 407, a thermosensitive in situ gel, during the sutureless technique significantly increases animal survival, compared to traditional methods. However, further improvement of this technology is greatly needed but remains unexplored. Here, we detected significant inflammation at the region of ureter anastomosis, after kidney transplantation using poloxamer 407. Since chemokines play a pivotal role during inflammation, we implanted an Alzet osmotic pump that gradually releases AMD3100 (a specific inhibitor of the binding of stromal cell-derived factor 1 (SDF-1) to its receptor, CXCR4) at the site of ureter anastomosis in mice that had undergone kidney transplantation. We found that AMD3100 significantly reduced local inflammation, significantly improved animal survival after kidney transplantation, and significantly improved kidney function. Together, these data suggest that inhibition of chemokine signaling at the site of ureter anastomosis may substantially improve animal survival after kidney transplantation through suppression of suturing-related inflammation.