Global targetome analysis reveals critical role of miR-29a in pancreatic stellate cell mediated regulation of PDAC tumor microenvironment

Identification of circular RNAs in cardiac hypertrophy and cardiac fibrosis

Cardiac hypertrophy initially serves as an adaptive response to physiological and pathological stimuli. Sustained hypertrophy progress to pathological cardiac hypertrophy, cardiac fibrosis and ultimately lead to heart failure, one of the leading medical causes of mortality worldwide. Intervention of pathological cardiac hypertrophy can effectively reduce the occurrence of heart failure. Abundant factors, such as adrenergic, angiotensin, and endothelin (ET-1) receptors, have been shown to participate in the regulation of pathological cardiac hypertrophy. Recently, an increasing number of studies have indicated that circRNA and circRNA-miRNA–mRNA network regulation is indispensable for the posttranscriptional regulation of mRNA in cardiac hypertrophy. In our study, the morphological, cardiac function and pathological changes during cardiac hypertrophy were investigated. RNA sequencing identified 93 circRNAs that were differentially expressed in the TAC_2w group, and 55 circRNAs in the TAC_4w group compared with the sham group. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses identified several significant pathways, including hypertrophic cardiomyopathy, extracellular matrix (ECM)-receptor interaction and focal adhesion. Coexpression analyses were performed for differentially expressed circRNAs and differentially expressed mRNAs. Based on gene set enrichment analysis (GSEA), 8 circRNAs (mmu-Nfkb1_0001, mmu-Smad4_0007, mmu-Hecw2_0009, mmu-Itgbl1_0002, mmu-Lrrc2_0005, mmu-Cpeb3_0007, mmu-Ryr2_0040, and mmu-Rtn4_0001) involved in cardiac hypertrophy and cardiac fibrosis were identified. We validated some key circRNAs by qPCR. The crucial coexpression of circRNA–mRNA and its interaction with miRNA showed the possible mechanism of circRNAs in the process of cardiac dysfunction. Our results may provide promising targets for the treatment of pathological cardiac hypertrophy and fibrosis.

N6 -methyladenosine RNA demethylase FTO regulates extracellular matrix-related genes and promotes pancreatic cancer cell migration and invasion

Pancreatic cancer (PC) is a deadly disease, and its post-transcriptional gene regulation mechanism remains unclear. The abundant extracellular matrix (ECM) in PC plays an important role in tumor progression. This study is the first to focus on the role of N⁶ -methyladenosine (m⁶ A) RNA methylation, an emerging post-transcriptional regulatory mechanism, in the regulation of the ECM in PC. Here, we found that ADAMTS2, COL12A1, and THBS2 were associated with the prognosis of PC by comprehensive analysis of differentially expressed genes from two independent GEO expression profile datasets and m⁶ A-related genes in RMVar database (PAAD). GO and KEGG enrichment analysis found that these m⁶ A-related targets are chiefly functionally concentrated in the ECM region and participate in ECM signal transduction. Correlation analysis revealed that these genes can be regulated by the demethylase FTO. Cell biology function assays showed that knockdown of FTO-inhibited PC cell abilities to migrate and invade in vitro. qRT-PCR and MeRIP experiments showed that after knockdown of FTO, the mRNA levels of ADAMTS2, COL12A1, and THBS2 and their m⁶ A modification levels were significantly reduced. These results indicate that m⁶ A RNA demethylation is associated with the regulation of ECM in PC. In conclusion, m⁶ A RNA demethylase FTO regulates ECM-related genes and promotes PC cell abilities to migrate and invade, our work provides a new perspective on the molecular mechanism of PC progression.

Effects of TP53 Mutations and miRs on Immune Responses in the Tumor Microenvironment Important in Pancreatic Cancer Progression

Approximately 90% of pancreatic cancers are pancreatic ductal adenocarcinomas (PDAC). PDAC is the fourth leading cause of cancer death world-wide. Therapies for PDAC are largely ineffective due to the dense desmoplastic tumor microenvironment which prevents chemotherapeutic drugs and small molecule inhibitors from exerting effective anti-cancer effects. In this review, we will discuss the roles of TP53 and miRs on the PDAC tumor microenvironment and how loss of the normal functions of TP53 promote tumor progression. The TP53 gene is mutated in approximately 50% of pancreatic cancers. Often, these TP53 mutations are point mutations which confer additional functions for the TP53 proteins. These are called gain of function (GOF) mutations (mut). Another class of TP53 mutations are deletions which result in loss of the TP53 protein; these are referred to TP53-null mutations. We have organized this review into various components/properties of the PDAC microenvironment and how they may be altered in the presence of mutant TP53 and loss of certain miR expression.

Gene Coexpression Network Characterizing Microenvironmental Heterogeneity and Intercellular Communication in Pancreatic Ductal Adenocarcinoma: Implications of Prognostic Significance and Therapeutic Target

Background

Pancreatic ductal adenocarcinoma (PDAC) is characterized by intensive stromal involvement and heterogeneity. Pancreatic cancer cells interact with the surrounding tumor microenvironment (TME), leading to tumor development, unfavorable prognosis, and therapy resistance. Herein, we aim to clarify a gene network indicative of TME features and find a vulnerability for combating pancreatic cancer.

Methods

Single-cell RNA sequencing data processed by the Seurat package were used to retrieve cell component marker genes (CCMGs). The correlation networks/modules of CCMGs were determined by WGCNA. Neural network and risk score models were constructed for prognosis prediction. Cell–cell communication analysis was achieved by NATMI software. The effect of the ITGA2 inhibitor was evaluated in vivo by using a Kras^G12D-driven murine pancreatic cancer model.

Results

WGCNA categorized CCMGs into eight gene coexpression networks. TME genes derived from the significant networks were able to stratify PDAC samples into two main TME subclasses with diverse prognoses. Furthermore, we generated a neural network model and risk score model that robustly predicted the prognosis and therapeutic outcomes. A functional enrichment analysis of hub genes governing gene networks revealed a crucial role of cell junction molecule–mediated intercellular communication in PDAC malignancy. The pharmacological inhibition of ITGA2 counteracts the cancer-promoting microenvironment and ameliorates pancreatic lesions in vivo.

Conclusion

By utilizing single-cell data and WGCNA to deconvolute the bulk transcriptome, we exploited novel PDAC prognosis–predicting strategies. Targeting the hub gene ITGA2 attenuated tumor development in a PDAC mouse model. These findings may provide novel insights into PDAC therapy.

Angelol-A exerts anti-metastatic and anti-angiogenic effects on human cervical carcinoma cells by modulating the phosphorylated-ERK/miR-29a-3p that targets the MMP2/VEGFA axis

AIMS

Angelol-A (Ang-A), a kind of coumarins, is isolated from the roots of Angelica pubescens f. biserrata. However, AA exerts antitumor effects and molecular mechanism on cervical cancer cells is unknown.

MAIN METHODS

Cell viability was determined using the MTT assay, and the cell cycle phase was assessed by PI staining with flow cytometry. Ang-A-treated cells with/without Antago-miR-29a-3p (miR-29a-3p inhibitor) or U0126 (MEK inhibitor) were assessed for the expression of miR-29a-3p, in vitro migration/invasion, and angiogenesis using qRT-PCR, a chemotaxis assay, and tube formation assay, respectively. The expression of mitogen-activated protein kinases/MMP2/MMP9/VEGFA was determined by western blot analysis with applicable antibodies.

KEY FINDINGS

Ang-A significantly inhibited MMP2 and VEGFA expression, cell migration, and invasive motility in human cervical cancer cells. Conditioned medium inhibited tube formation in HUVECs. Ang-A principally inhibited invasive motility and angiogenesis by upregulating the expression of miR-29a-3p that targets the VEGFA-3' UTR. The role of miR-29a-3p was confirmed using Antago-miR-29a-3p, which reversed the Ang-A-inhibited expression of MMP2 and VEGFA, invasive motility, and angiogenesis in human cervical cancer cells. The ERK pathway was implicated in mediating the metastatic and angiogenic action of Ang-A. Combined treatment with Ang-A treated and U0126 exerted a synergistic inhibitory effect on the expression of MMP2 and VEGFA and the metastatic and angiogenic properties of human cervical cancer cells.

SIGNIFICANCE

These findings are the first to indicate that in human cervical cancer cells, Ang-A exerts anti-metastatic and anti-angiogenic effects via targeting the miR-29a-3p/MMP2/VEGFA axis, mediated through the ERK pathway.

Identification of DDX31 as a Potential Oncogene of Invasive Metastasis and Proliferation in PDAC

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignant tumors worldwide and has poor prognosis. DEAD box proteins31 (DDX31) participate in cellular processes involving RNA secondary structure changes. However, the functions of DDX31 in PDAC remain to be elucidated.

Methods: The key gene DDX31 was identified using a combination of a risk model and weighted gene co-expression network analysis (WGCNA) with R software. The biological functions of DDX31 in PDAC were investigated through bioinformatics analysis and in vitro experiments.

Results: Combining with WGCNA and risk model, DDX31 was identified as a potential factor of the invasive metastasis properties of PDAC, and its expression was closely related to the malignant differentiation of PDAC. The results of gene set enrichment analysis (GSEA) showed that DDX31 was correlated with cell invasive metastasis and proliferation by activating MAPK signaling pathway. The inhibition of DDX31 inhibited the invasion and migration of PDAC cells. Survival analysis showed that DDX31 expression was negatively associated with the poor prognosis in patients with PDAC.

Interpretation:DDX31 may be a potential factor for PDAC. The inhibition of DDX31 may be a potential way to treat PDAC.

CircRNA-miRNA networks in regulating bone disease

Circular RNA (circRNA) is a class of endogenous noncoding RNA (ncRNA), presenting as a special covalent closed loop without a 5' cap or 3' tail, maintaining resistance to RNA exonuclease and keeping high stability. Although lowly expressed in most situations, circRNA makes an active difference in regulating physiological or pathological processes by modulating gene expression by regulation of transcription, protein, and miRNA functions through various mechanisms in particular tissues. Recent studies have demonstrated the roles of the miRNA-circRNA network in the development of several bone diseases such as osteoporosis, a multiple-mechanism disease resulting from defective bone quality and low bone mass, osteoarthritis, whose main pathomechanism is inflammation and articular cartilage degradation, as well as osteosarcoma, known as one of the most common bone cancers. However, the specific mechanism of how circRNA along with miRNA influences those diseases is not well documented, showing potential for the development of new therapies for those bone diseases.

Loss of miR-29a/b1 promotes inflammation and fibrosis in acute pancreatitis

MicroRNA-29 (miR-29) is a critical regulator of fibroinflammatory processes in human diseases. In this study, we found a decrease in miR-29a in experimental and human chronic pancreatitis, leading us to investigate the regulatory role of the miR-29a/b1 cluster in acute pancreatitis (AP) utilizing a conditional miR-29a/b1-KO mouse model. miR-29a/b1-sufficient (WT) and -deficient (KO) mice were administered supramaximal caerulein to induce AP and characterized at different time points, utilizing an array of IHC and biochemical analyses for AP parameters. In caerulein-induced WT mice, miR-29a remained dramatically downregulated at injury. Despite high-inflammatory milieu, fibrosis, and parenchymal disarray in the WT mice during early AP, the pancreata fully restored during recovery. miR-29a/b1-KO mice showed significantly greater inflammation, lymphocyte infiltration, macrophage polarization, and ECM deposition, continuing until late recovery with persistent parenchymal disorganization. The increased pancreatic fibrosis was accompanied by enhanced TGFβ1 coupled with persistent αSMA+ PSC activation. Additionally, these mice exhibited higher circulating IL-6 and inflammation in lung parenchyma. Together, this collection of studies indicates that depletion of miR-29a/b1 cluster impacts the fibroinflammatory mechanisms of AP, resulting in (a) aggravated pathogenesis and (b) delayed recovery from the disease, suggesting a protective role of the molecule against AP.

The correlation of the miR-29a/MMP9 axis with Helicobacter pylori infection in gastric cancer

OBJECTIVE

This study was designed to investigate the association between the miR-29a/MMP9 axis expression levels and Helicobacter pylori (HP) infection in gastric cancer patients.

METHODS

A total of 100 gastric cancer patients referred to our hospital from June 2017 to June 2019 were recruited as the study cohort. Among them, 50 HP-positive patients were included in the experimental group and 50 HP-negative patients were included in the control group. The changes in the patients' conditions were compared, the miR-29a/MMP9 axis expression levels were recorded, and the correlation between the miR-29a/MMP9 axis and the HP infections was analyzed. All the discharged patients were followed up for one year to analyze the correlation between the HP infections and the serum miR-29a and MMP9 expression levels with the disease progression.

RESULTS

The experimental group had higher miR-29a expression levels and higher MMP9 chromogenic scores than the control group (P<0.05). A negative correlation was found between the miR-29 expression level and the MMP9 expression level (r=-5.369, P<0.05). One year after discharge, there were 27 patients with severe disease in the experimental group and 6 in the control group, with a significant difference between the two groups. Moreover, the expression levels of the miR-29a/MMP9 axis were significantly higher in the discharged patients than in the patients with severe disease (P<0.05). A receiver operating characteristic (ROC) curve was used to analyze the predictive value of miR-29/MMP9 in the diagnosis of gastric cancer, and the area under the curve was found to be 0.97.

CONCLUSION

The miR-29a/MMP9 axis levels were increased in the HP positive patients but not in the HP negative patients. HP infection is considered to be closely related to gastric cancer cell spread, disease relapse, and high miR-29a/MMP9 axis expression levels.

miRNA‑7515 suppresses pancreatic cancer cell proliferation, migration and invasion via downregulating IGF‑1 expression

Pancreatic cancer (PC) is a lethal malignancy of the gastrointestinal tract. Previous studies have reported that microRNAs (miRNAs/miRs) are involved in the tumorigenesis of PC. Therefore, the present study aimed to determine the effects of miR‑7515 on PC cell proliferation, invasion and migration in vitro and in vivo, and investigate its underlying molecular mechanism using bioinformatics, double luciferase assay and western blotting. The results revealed that the expression levels of miR‑7515 were downregulated in PC, which predicted a poor clinical outcome. The overexpression of miR‑7515 significantly decreased the proliferation, invasive and migratory abilities of PC cells in vitro and in vivo, while the knockdown of miR‑7515 exerted the opposite effects. miR‑7515 was identified to directly bind to insulin‑like growth factor 1 (IGF‑1) and downregulate its expression, which subsequently downregulated the Ras/Raf/MEK/ERK signalling pathway. The overexpression of IGF‑1 reversed the inhibitory effects of miR‑7515 overexpression on PC cells. In conclusion, the findings of the present study indicated that miR‑7515 may act as a tumor suppressor in PC, as it repressed PC cell proliferation invasion and migration via downregulating the expression of IGF‑1 and the activity of the Ras/Raf/MEK/ERK signalling pathways.

miR-29a-3p-dependent COL3A1 and COL5A1 expression reduction assists sulforaphane to inhibit gastric cancer progression

The antitumor properties of cruciferous vegetables are mainly due to their high content of isothiocyanates, and sulforaphane (SFA) is the most well-known compound. The aim of this study was to determine the mechanism of SFA inhibiting gastric cancer (GC) progression. After verifying SFA suppressing GC growth in vivo, we utilized the GSE79973 and GSE118916 datasets to identify the GC development signatures that overlap with the RNA-seq analysis in SFA-treated AGS cells. GSEA of the RNA-seq data indicated that SFA regulation of GC progression was related to extracellular matrix and collagens; thus, we identified COL3A1 and COL5A1 as the targets of SFA, which functioned as oncogenes. We found positive correlations between COL3A1 and COL5A1 expression in GC cells, and confirmed that miR-29a-3p is the common regulator of their expression. RNA immunoprecipitation assays based on Ago2, Dicer, and exportin-5 showed that SFA could promote mature miR-29a-3p generation. We also proved that SFA inactivated the Wnt/β-catenin pathway in GC cells in a miR-29a-3p-dependent manner. Overall, SFA boosts miR-29a-3p maturation to downregulate COL3A1 and COL5A1 and inactivate the Wnt/ β -catenin pathway to suppress GC progression.

Unusual Case of Pancreatic Adenocarcinoma with Bladder Metastasis

Background: The pancreas can be the site of neoplasms of several histogenetic origins; in most cases, tumors derive from the exocrine component, and ductal adenocarcinoma certainly prevails over the others. This tumor displays remarkably aggressive behavior, and it is often diagnosed at a late stage of disease. Case presentation: We discuss the rare case of a 76-year-old male with locally advanced pancreatic head adenocarcinoma who developed uncommon metastatic disease. The bladder constitutes a very rare site of metastases, mostly deriving from melanoma, gastric, lung and breast cancers. The bladder's secondary involvement in pancreatic malignancies represents an extremely unusual occurrence, and there are very few cases described in the literature to date. Conclusions: The finding of pancreatic adenocarcinoma metastases leads to a poor prognosis, and patients who are diagnosed at this stage constitute 53% of cases, with a 5-year survival of 3%. Although rare, therefore, the diagnostic hypothesis of pancreatic ductal adenocarcinoma (DAC) metastases to the bladder must, in some cases, be considered, especially if accompanied by a clinical picture that may suggest it.