miR-196b regulates gastric cancer cell proliferation and invasion via PI3K/AKT/mTOR signaling pathway

MiRNA-766-3p inhibits gastric cancer via targeting COL1A1 and regulating PI3K/AKT signaling pathway

Objective MiRNA-766-3p has been shown to be associated with a variety of cancers. However, few studies have been done in gastric cancer (GC). This study explores the mechanism of miR-766-3p in GC. Methods The potential targets of microRNA (miRNA) were predicted using Tarbase and Targetscan databases. The results are intersected with differential genes (DEGs) (fold change > 1.5, P < 0.05) in gastric cancer to obtain potential core targets. The hub targets screened by constructing PPI networks (degree > 5, expression > 0.5). Validating the differential expression and expression in immunohistochemistry of these targets through the database. And the binding sites between miRNAs and mRNAs were verified using dual-luciferase Assay. Finally, qRT-PCR and Western Blot experiments were conducted to validate the hub targets and signal pathways. Results The potential hub targets from the PPI network were THBS2, COL1A1, FGG, FGB, and PLAU. Combining database, luciferase Assay and experimental validation, miR-766-3p can sponge COL1A1 and it plays the most important role in gastric cancer progression. In GC, COL1A1 was upregulated and the enrichment analysis revealed that COL1A1 regulates PI3K/AKT signal pathway, and AKT is also highly expressed in gastric cancer. Conclusion The miR-766-3p can inhibit the progression of gastric cancer by targeting COL1A1 and regulating the PI3K/AKT signal pathway. It could be a potential therapy option for the GC.

Iridium(III) complex induces apoptosis in HeLa cells by regulating mitochondrial and PI3K/AKT signaling pathways: In vitro and in vivo experiments

Cyclometalated iridium complexes with mitochondrial targeting show great potential as substitutes for platinum-based complexes because of their strong anti-cancer properties. Three novel cyclometalated iridium(III) compounds were synthesized and evaluated in five different cell lines as part of the ongoing systematic investigations of these compounds. The complexes were prepared using 4,7-dichloro-1,10-phenanthroline ligands. The cytotoxicity of complexes Ir1-Ir3 towards HeLa cells was shown to be high, with IC50 values of 0.83±0.06, 4.73±0.11, and 4.95±0.62 μM, respectively. Complex Ir1 could be ingested by HeLa cells in 3 h and has shown high selectivity toward mitochondria. Subsequent investigations demonstrated that Ir1 triggered apoptosis in HeLa cells by augmenting the generation of reactive oxygen species (ROS), reducing the mitochondrial membrane potential, and depleting ATP levels. Furthermore, the movement of cells was significantly suppressed and the progression of the cell cycle was arrested in the G0/G1 phase following the administration of Ir1. The Western blot analysis demonstrated that the induction of apoptosis in HeLa cells by Ir1 involves the activation of the mitochondria-dependent channel and the PI3K/AKT signaling pathway. No significant cytotoxicity was observed in zebrafish embryos at concentrations less than or equal to 16 µM, e.g., survival rate and developmental abnormalities. In vivo, antitumor assay demonstrated that Ir1 suppressed tumor growth in mice. Therefore, our work shows that complex Ir1 could be a promising candidate for developing novel antitumor drugs.

Circular RNA circ_0006089 promotes the progression of gastric cancer by regulating the miR-143-3p/PTBP3 axis and PI3K/AKT signaling pathway

OBJECTIVES

Circular RNAs (circRNAs) play pivotal roles in malignancies including gastric cancer (GC). We aimed to investigate the biological function and regulatory mechanism of circ_0006089 in GC.

METHODS

Circ_0006089, microRNA (miR)-143-3p, and polypyrimidine tract-binding protein 3 (PTBP3) expressions were measured via quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) in GC cell lines. Cell proliferative capacity was determined by colony formation and CCK-8 assays. Flow cytometry was employed for measuring cell apoptosis. Cell invasion and migration were measured via transwell and wound-healing assays. Western blot analysis was utilized for detecting protein expressions of E-cadherin, N-cadherin, vimentin, PTBP3, PI3K, p-PI3K, AKT, and p-AKT. Dual-reporter luciferase analysis was conducted to confirm the association between miR-143-3p and circ_0006089 or PTBP3. The role of circ_0006089 in vivo was detected via establishing a mice xenograft model.

RESULTS

Circ_0006089 expression was increased in GC. Circ_0006089 downregulation suppressed the proliferation and metastasis and induced apoptosis of GC cells, which was counteracted by miR-143-3p inhibition or PTBP3 overexpression. In addition, circ_0006089 overexpression could promote GC progression. MiR-143-3p specially bound to circ_0006089 and PTBP3 was targeted by miR-143-3p. Moreover, circ_0006089 could regulate PTBP3 expression and the PI3K/AKT pathway by sponging miR-143-3p. Circ_0006089 knockdown also suppressed tumor growth.

CONCLUSION

Circ_0006089 regulated miR-143-3p/PTBP3/PI3K/AKT pathway to facilitate GC progression.

Endocrine disruptor chlorpyrifos promotes migration, invasion, and stemness phenotype in 3D cultures of breast cancer cells and induces a wide range of pathways involved in cancer progression

Organophosphorus chlorpyrifos (CPF) is currently considered an endocrine disruptor (ED), as it can imitate hormone actions both in vitro and in vivo. We recently reported that CPF induces migration and invasion in 2D cultures and changes the expression of key molecular markers involved in epithelial mesenchymal transition in MCF-7 and MDA-MB-231 cell lines. In this study, we investigated whether CPF could behave as a predisposing factor for tumors to become more metastatic and aggressive using 3D culture models. In MCF-7 cells, 0.05 μM CPF induced an increase in the number and size of mammospheres via estrogen receptor alpha (ERα) and c-SRC. Furthermore, 0.05 μM CPF increased the area of spheroids generated from MCF-7 cells, induced invasion using both Matrigel® and type 1 collagen matrices, and increased cell migration capacity via ERα in this 3D model. In turn, 50 μM CPF increased cell migration capacity and invasion using type 1 collagen matrix. In monolayers, CPF increased the phosphorylation and membrane translocation of c-SRC at both concentrations assayed. CPF at 0.05 μM boosted p-AKT, p-GSK-3β and p-P38. While p-AKT rose in a ERα-dependent way, p-GSK-3β was dependent on ERα- and c-SRC, and p-P38 was only dependent on c-SRC. On the other hand, the increase in p-AKT and p-P38 induced by 50 μM CPF was dependent on the c-SRC pathway. We also observed that 0.05 μM CPF increased IGF-1R and IRS-1 expression and that 50 μM CPF induced IGF-1Rβ phosphorylation. In the MDA-MB-231 cell line, 0.05 and 50 μM CPF increased p-c-SRC. Finally, p-AKT and p-GSK-3β were also induced by CPF at 0.05 and 50 μM, and an increase in p-P38 was observed at 50 μM. Taken together, these data provide support for the notion that CPF may represent a risk factor for breast cancer development and progression.

The Pathogenic Role of PI3K/AKT Pathway in Cancer Onset and Drug Resistance: An Updated Review

The PI3K/AKT pathway is one of the most frequently over-activated intracellular pathways in several human cancers. This pathway, acting on different downstream target proteins, contributes to the carcinogenesis, proliferation, invasion, and metastasis of tumour cells. A multi-level impairment, involving mutation and genetic alteration, aberrant regulation of miRNAs sequences, and abnormal phosphorylation of cascade factors, has been found in multiple cancer types. The deregulation of this pathway counteracts common therapeutic strategies and contributes to multidrug resistance. In this review, we underline the involvement of this pathway in patho-physiological cell survival mechanisms, emphasizing its key role in the development of drug resistance. We also provide an overview of the potential inhibition strategies currently available.

Epigenetic Regulation of microRNAs in Cancer: Shortening the Distance from Bench to Bedside

Cancer is a complex disease involving alterations of multiple processes, with both genetic and epigenetic features contributing as core factors to the disease. In recent years, it has become evident that non-coding RNAs (ncRNAs), an epigenetic factor, play a key role in the initiation and progression of cancer. MicroRNAs, the most studied non-coding RNAs subtype, are key controllers in a myriad of cellular processes, including proliferation, differentiation, and apoptosis. Furthermore, the expression of miRNAs is controlled, concomitantly, by other epigenetic factors, such as DNA methylation and histone modifications, resulting in aberrant patterns of expression upon the occurrence of cancer. In this sense, aberrant miRNA landscape evaluation has emerged as a promising strategy for cancer management. In this review, we have focused on the regulation (biogenesis, processing, and dysregulation) of miRNAs and their role as modulators of the epigenetic machinery. We have also highlighted their potential clinical value, such as validated diagnostic and prognostic biomarkers, and their relevant role as chromatin modifiers in cancer therapy.

Silencing of LncRNA PVT1 inhibits the proliferation, migration and fibrosis of high glucose-induced mouse mesangial cells via targeting microRNA-93-5p

Objective: The present study aimed to investigate the regulatory role of long non-coding RNA plasmacytoma variant translocation 1 (PVT1) on high glucose (HG)-induced mouse mesangial cells (MMCs).

Methods: PVT1 expression in diabetic nephropathy (DN) mice and HG-induced MMCs was detected by qRT-PCR. EdU and Colony formation, Annexin V-PI staining, Muse cell cycle, Scratch, and Transwell assays were performed to detect the cell proliferation, apoptosis, cell cycle, migration, and invasion, respectively. The contents of fibrosis factors in cell-culture supernatants were detected by enzyme-linked immunosorbent assay (ELISA). Western blot was performed to detect the expression of factors involved in apoptosis, cell cycle, migration and invasion, fibrosis, and PI3K/Akt/mTOR pathway. The targeting relation between miR-93-5p and PVT1 was predicted by StarBase3.0 (an online software for analyzing the targeting relationship) and identified by Dual-luciferase reporter (DLR) assay.

Results: PVT1 was overexpressed in DN kidney tissues and HG-induced MMCs. HG-induced MMCs exhibited significantly increased EdU-positive cells, cell colonies, S and G₂/M phase cells, migration and invasion ability, and contents of fibrosis factors, as well as significantly decreased apoptosis rate compared with NG-induced MMCs. HG significantly up-regulated Bcl-2, CyclinD1, CDK4, N-cadherin, vimentin, Col. IV, FN, TGF-β1 and PAI-1, and down-regulated Bax, cleaved caspase-3, cleaved PARP, and E-cadherin in MMCs. Silencing of PVT1 eliminated the effects of HG in MMCs and blocked PI3K/Akt/mTOR pathway. MiR-93-5p was a target of PVT1, which eliminated the effects of PVT1 on HG-induced MMCs.

Conclusions: PVT1 silencing inhibited the proliferation, migration, invasion and fibrosis, promoted the apoptosis, and blocked PI3K/Akt/mTOR pathway in HG-induced MMCs via up-regulating miR-93-5p.

Downregulation of hepatitis C virus replication by miR-196a using lentiviral vectors

Hepatitis C virus (HCV) is a positive-sense, single-stranded RNA virus that causes chronic hepatitis and hepatocellular carcinoma. Cellular microRNAs (miRNAs) directly modulate the viral infectivity and indirectly through targeting virus-related host factors. They play an essential role in the progression of different stages of HCV infection. The roles of miR-196 family in HCV infection and hepatocellular carcinoma progression remain poorly understood. Using ViTa databases, miR-196a as a high-score miRNA targeting the NS₅ A region of HCV genome was selected. Using dual luciferase assay and an established cell-cultured HCV (HCVcc) system, the effect of miR-196a on HCV genome was assessed. In silico analysis demonstrated the significant role of miR-196a in the downregulation of HCV replication. Using dual luciferase assay, the liver-specific miR-196a and NS₅ A gene binding was confirmed. To assess the experimental role of miR-196a, an HCVcc system was established in the Huh 7.5 cell lines. The HCV-RNA 1b derived from an infected patient was transfected into Huh 7.5 cells containing miR-196a lentiviral vectors (Huh 7.5/miR-196a), mocks (Huh 7.5/mock vector), and naïve Huh 7.5 cells. The rate of reduction of the HCV genome replication was assessed using relative real-time PCR assay. These results represent miR-196a overexpression and its roles in regulating HCV genome replication. However, miR-196a may inhibit HCV replication and accelerate the early stages of apoptosis. Overexpression of miR-196a in Huh 7.5 replicon cell is a potential new strategy to prevent hepatitis C infection. The results of this study suggest that miR-196a directly downregulates HCV replication and may serve as a new antiviral therapy.

MicroRNA-196b promotes gastric cancer progression by targeting ECRG4

Gastric cancer is one of the most common malignant tumors. MicroRNA-196b (miR-196b) has been demonstrated to play important roles in human cancers. However, its functions in gastric cancer progression were still largely unknown. In this study, the expression of miR-196b was determined by quantitative real-time PCR. Esophageal cancer-related gene 4 (ECRG4) level was examined by western blot assay and immunohistochemistry staining assay. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) assay and colony formation assay. Cell migration and invasion were analyzed by transwell assay. The association between miR-196b and ECRG4 was analyzed by dual-luciferase reporter assay. The functional role of miR-196b in vivo was analyzed by murine xenograft assay. As a result, we found the expression of miR-196b was elevated and the protein expression of ECRG4 was reduced in gastric cancer tissues and cells. MiR-196b inhibition suppressed gastric cancer cell proliferation, migration and invasion. ECRG4 was a target of miR-196b and its protein expression was negatively regulated by miR-196b. Moreover, ECRG4 overexpression showed similar effects with miR-196b inhibition on the malignant behaviors of GC cells and ECRG4 knockdown reversed the effects of miR-196b inhibition on gastric cancer cell proliferation, migration and invasion. In addition, miR-196b inhibition suppressed tumor volume and weight in vivo. In conclusion, downregulation of miR-196b inhibited gastric cancer progression by modulating ECRG4 expression, indicating that miR-196b might be a potential therapeutic target for gastric cancer.

MiR-196: emerging of a new potential therapeutic target and biomarker in colorectal cancer

Deregulation of microRNAs, as key elements in colorectal cancer (CRC) pathogenesis, is correlated with various stages of this cancer. miR-196 is involved in the initiation and progression of a verity of malignances, especially CRC. miR-196 in CRC cells could target different types of genes with oncogenic and/or tumor suppressor function such as HOX genes, GATA6, SOCS1, SOCS3, ANXA1, DFFA, PDCD4, ZG16 and ING5. Therefore, these genes could be up or down-regulated in cells and subsequently change the capacity of CRC cells in terms of tumor development, progression and, response to therapy. Comprehension of miR-196-associated aberrations underlying the CRC pathogenesis might introduce promising targets for therapy. Additionally, it seems that miR-196 expression profiling, especially circulatory exosomal miR-196, might be useful for diagnosis and prognosis determination of the CRC patients. In this review, at first, we summarize the roles of miR-196 in different types of cancers. After that, a detailed discussion about this miRNA and also their targets in CRC pathogenesis, progression, and response to treatment are represented. Moreover, we highlight the potential utilization of miR-196 and its targets as therapeutic targets and novel biomarkers in early detection and prediction of prognosis in CRC patients.

Protective role of microRNA-27a upregulation and HSP90 silencing against cerebral ischemia-reperfusion injury in rats by activating PI3K/AKT/mTOR signaling pathway

OBJECTIVE

MicroRNAs (miRNAs) have been reported in cerebral ischemia-reperfusion injury, yet the function of miR-27a in it has seldom been mentioned. This study aims to assess the mechanisms of miR-27a in rats with cerebral ischemia-reperfusion injury.

METHODS

The cerebral ischemia-reperfusion models of rat pups were established by bilateral carotid artery occlusion. Rats were treated with miR-27a agomir, silenced HSP90 expression plasmids or PI3K/AKT/mTOR pathway agonist. Oxidative stress indices, inflammatory factors, brain tissue water content, cerebral infarct volume, neurological function score and neuronal apoptosis in rats with cerebral ischemia-reperfusion injury were measured. MiR-27a and HSP90 expression and PI3K/AKT/mTOR phosphorylation levels in the brain tissues of rats were also detected.

RESULTS

MiR-27a expression and PI3K/AKT/mTOR phosphorylation levels were downregulated while HSP90 expression was upregulated in cerebral ischemia-reperfusion injury rats. Elevated miR-27a or reduced HSP90 diminished water content, neuronal apoptosis and infarct volume, suppressed oxidative stress and inflammatory response, as well as improved neurological deficits and pathological damages. Moreover, elevated miR-27a or silenced HSP90 upregulated PI3K/AKT/mTOR phosphorylation levels in cerebral ischemia-reperfusion injury rats. HSP90 silencing or PI3K/AKT/mTOR pathway agonist reversed the unfavorable effects of low miR-27a expression on cerebral ischemia-reperfusion injury rats.

CONCLUSION

To conclude, our study demonstrates that elevated miR-27a or decreased HSP90 attenuates oxidative stress and inflammatory response, and improves neurological function in cerebral ischemia-reperfusion injury rats by activating PI3K/AKT/mTOR signaling pathway.

Role of PI3K/AKT pathway in cancer: the framework of malignant behavior

Given that the PI3K/AKT pathway has manifested its compelling influence on multiple cellular process, we further review the roles of hyperactivation of PI3K/AKT pathway in various human cancers. We state the abnormalities of PI3K/AKT pathway in different cancers, which are closely related with tumorigenesis, proliferation, growth, apoptosis, invasion, metastasis, epithelial-mesenchymal transition, stem-like phenotype, immune microenvironment and drug resistance of cancer cells. In addition, we investigated the current clinical trials of inhibitors against PI3K/AKT pathway in cancers and found that the clinical efficacy of these inhibitors as monotherapy has so far been limited despite of the promising preclinical activity, which means combinations of targeted therapy may achieve better efficacies in cancers. In short, we hope to feature PI3K/AKT pathway in cancers to the clinic and bring the new promising to patients for targeted therapies.

miR-196b-5p controls adipocyte differentiation and lipogenesis through regulating mTORC1 and TGF-β signaling

MicroRNAs have been reported to play a role in adipogenesis and obesity. This study was performed to investigate the role of miR-196b-5p in adipogenesis and the mechanism involved. The data revealed that miR-196b-5p expression increased in primary or established marrow stromal progenitor cells after adipogenic treatment. Supplementing miR-196b-5p in the progenitor cells stimulated adipogenic differentiation and lipogenesis, along with the induction of adipogenic and lipogenic factors. Conversely, inhibition of endogenous miR-196b-5p blocked adipogenesis and lipogenesis. Tuberous sclerosis 1 (Tsc1) and transforming growth factor-β receptor 1 (TGFBR1) were demonstrated to be the direct target genes of miR-196b-5p. Supplementing miR-196b-5p activity in progenitor cells reduced the protein level of TSC1 and activated mammalian target of rapamycin complex 1 (mTORC1) signaling. We further demonstrated that the perturbation of TSC1 in progenitor cells altered the trend of adipogenic differentiation and lipogenesis. Overexpression of Tsc1 or inactivation of mTORC1 signaling attenuated the stimulation of adipogenic differentiation and lipogenesis by miR-196b-5p. Overexpression of Tgfbr1 also partially blocked the adipogenic effect of miR-196b-5p. Further investigations demonstrated that zinc finger E-box-binding homeobox 1 (ZEB1) transcriptionally upregulated miR-196b-5p expression. The current study suggests that miR-196b-5p promotes adipogenic differentiation and lipogenesis in progenitor cells through targeting TSC1 and TGFBR1 and therefore regulating mTORC1 and TGF-β signaling.

MicroRNA-196b-5p promotes malignant progression of colorectal cancer by targeting ING5

Background

miR-196b-5p expression is deregulated in many malignant tumors. Although miR-196b-5p has been implicated in the malignant transformation of colorectal cancer, its role in this specific type of cancer has not been fully explored. Thus, the present study was aimed to examine the cellular function of miR-196b-5p and its role in malignant biological behavior in colorectal cancer.

Methods

miR-196b-5p expression was measured in colorectal cancer tissues and cell lines using quantitative real-time PCR. Cell counting kit-8 (CCK-8) assay and Transwell assay were used to detect proliferation, migration, and invasion in cell lines, whereas flow cytometry was applied to study apoptosis. Western blot analysis was performed to measure the protein levels. Dual luciferase reporter assay was used to investigate the interaction between miR-196b-5p and ING5. Tumor formation was evaluated in mice.

Results

MiR-196b-5p was abundantly expressed in colorectal cancer tissues and cell lines, whereas ING5 was expressed at low levels. MiR-196b-5p was successfully overexpressed or knocked down in colorectal cancer cells. We found that miR-196b-5p overexpression significantly accelerated the proliferation, cell cycle, migration and invasion, while inhibited cell apoptosis in colorectal cancer cells. However, miR-196b-5p inhibitor showed the opposite effects. Moreover, ING5 overexpression or knockdown was successfully performed in colorectal cancer cells. ING5 overexpression suppressed proliferation, migration, invasion, the phosphorylation of PI3K, Akt as well as MEK, and promoted cell apoptosis, which could be reversed by ING5 knockdown. Additionally, ING5 was identified as a target of miR-196b-5p through bioinformatics analysis and a luciferase activity assay. Furthermore, ING5 knockdown could attenuate the decrease in proliferation, migration, invasion, and the protein levels of p-PI3K, p-Akt, and p-MEK, which were induced by miRNA-196b-5p inhibitor. Besides, miR-196b-5p knockdown inhibited tumor growth, whereas ING5 knockdown elevated it in vivo.

Conclusions

In conclusion, miR-196b-5p promotes cell proliferation, migration, invasion, and inhibits apoptosis in colorectal cancer by targeting ING5.

Total saponins of Bolbostemma paniculatum (maxim.) Franquet exert antitumor activity against MDA-MB-231 human breast cancer cells via inhibiting PI3K/Akt/mTOR pathway

BACKGROUND

The aim of the present study was to examine the effects of the Bolbostemma paniculatum (Maxim.) Franquet (BP) active compound, BP total saponins (BPTS), on MDA-MB-231 cells, and investigate the underlying mechanism regarding BPTS-mediated attenuation of the PI3K/Akt/mTOR pathway.

METHODS

The effect of BPTS on cytotoxicity, induction of apoptosis and migration on MDA-MB-231 cells at three different concentrations was investigated. A CCK-8 assay, wound-healing assay and flow cytometry were used to demonstrate the effects of BPTS. Additionally, expression of the primary members of the PI3K/Akt/mTOR signaling pathway was assessed using western blotting. To verify the underlying mechanisms, a PI3K inhibitor and an mTOR inhibitor were used.

RESULTS

BPTS inhibited proliferation of MDA-MB-231 cells with an IC50 value of 10 μg/mL at 48 h. BPTS inhibited migration of MDA-MB-231 cells, and the western blot results demonstrated that BPTS reduced p-PI3K, p-Akt and p-mTOR protein expression levels in MDA-MB-231 cells. Additionally, the results were confirmed using a PI3K inhibitor and an mTOR inhibitor. BPTS decreased proliferation and migration of MDA-MB-231 cells possibly through inhibiting the PI3K/Akt/mTOR signaling pathway.

CONCLUSIONS

The results highlight the therapeutic potential of BPTS for treating patients with triple-negative breast cancer.

Anticancer effect of resibufogenin on gastric carcinoma cells through the phosphoinositide 3-kinase/protein kinase B/glycogen synthase kinase 3β signaling pathway

The aim of the present study was to investigate the anticancer effect of resibufogenin in gastric carcinoma cells through the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3β (GSK3β) signaling pathway. MGC-803 cells were treated with 0, 1, 2, 4 and 8 µM resibufogenin for 12, 24 and 48 h. Cell viability and apoptosis were measured using an MTT assay and annexin V staining. Caspase-3 and caspase-8 activity were identified using caspase-3 and caspase-8 activity kits and a variety of protein expression [B cell lymphoma (Bcl)-2, Bcl-2-associated X protein (Bax), cyclin D1, cyclin E, PI3K, phosphorylated AKT, phosphorylated GSK3β and β-catenin] were quantified using western blot analysis. It was revealed that resibufogenin effectively inhibited cell proliferation, and induced apoptosis and caspase-3 and caspase-8 activity in MGC-803 cells. Furthermore, treatment with resibufogenin effectively increased Bax/Bcl-2 expression, and suppressed cyclin D1, cyclin E, PI3K, phosphorylated AKT, phosphorylated GSK3β and β-catenin protein expression in MGC-803 cells. These results suggest that the anticancer effect of resibufogenin induces gastric carcinoma cell death through the PI3K/AKT/GSK3β signaling pathway, offering a novel view of the mechanism by which resibufogenin functions as an agent to treat gastric carcinoma.

MicroRNA-focused CRISPR-Cas9 library screen reveals fitness-associated miRNAs

MicroRNAs (miRNAs) are post-transcriptional gene regulators that play important roles in the control of cell fitness, differentiation, and development. The CRISPR-Cas9 gene-editing system is composed of the Cas9 nuclease in complex with a single guide RNA (sgRNA) and directs DNA cleavage at a predetermined site. Several CRISPR-Cas9 libraries have been constructed for genome-scale knockout screens of protein function; however, few libraries have included miRNA genes. Here we constructed a miRNA-focused CRISPR-Cas9 library that targets 1594 (85%) annotated human miRNA stem-loops. The sgRNAs in our LX-miR library are designed to have high on-target and low off-target activity, and each miRNA is targeted by four to five sgRNAs. We used this sgRNA library to screen for miRNAs that affect cell fitness of HeLa or NCI-N87 cells by monitoring the change in frequency of each sgRNA over time. By considering the expression in the tested cells and the dysregulation of the miRNAs in cancer specimens, we identified five HeLa pro-fitness and cervical cancer up-regulated miRNAs (miR-31-5p, miR-92b-3p, miR-146b-5p, miR-151a-3p, and miR-194-5p). Similarly, we identified six NCI-N87 pro-fitness and gastric cancer up-regulated miRNAs (miR-95-3p, miR-181a-5p, miR-188-5p, miR-196b-5p, miR-584-5p, and miR-1304-3p), as well as three anti-fitness and down-regulated miRNAs (let-7a-3p, miR-100-5p, and miR-149-5p). Some of those miRNAs are known to be oncogenic or tumor-suppressive, but others are novel. Taken together, the LX-miR library is useful for genome-wide unbiased screening to identify miRNAs important for cellular fitness and likely to be useful for other functional screens.

Gastrin inhibits gastric cancer progression through activating the ERK-P65-miR23a/27a/24 axis

BACKGROUND

To test the hypothesis that activated extracellular signal-regulated kinase (ERK) regulates P65-miR23a/27a/24 axis in gastric cancer (GC) and the ERK-P65-miR23a/27a/24 axis plays an important role in the development of GC, and to evaluate the role of gastrin in GC progression and ERK-P65-miR23a/27a/24 axis.

METHODS

The component levels of the ERK-P65-miR23a/27a/24 axis in four fresh GC tissues, 101 paraffin-embedded GC tissues and four GC cell lines were determined by Western blotting, immunohistochemistry (IHC) or qRT-PCR. The effects of gastrin on GC were first evaluated by measuring gastrin serum levels in 30 healthy and 70 GC patients and performing a correlation analysis between gastrin levels and survival time in 27 GC patients after eight years of follow-up, then evaluated on GC cell lines, GC cell xenograft models, and patient-derived xenografts (PDX) mouse models. The roles of ERK-P65-miR23a/27a/24 axis in GC progression and in the effects of gastrin on GC were examined.

RESULTS

ERK- P65-miR23a/27a/24 axis was proved to be present in GC cells. The levels of components of ERK-P65-miR23a/27a/24 axis were decreased in GC tissue samples and PGC cells. The decreased levels of components of ERK-P65-miR23a/27a/24 axis were associated with poor prognosis of GC, and ERK-P65-miR23a/27a/24 axis played a suppressive role in GC progression. Low blood gastrin was correlated with poor prognosis of the GC patients and decreased expression of p-ERK and p-P65 in GC tissues. Gastrin inhibited proliferation of poorly-differentiated GC (PGC) cells through activating the ERK-P65-miR23a/27a/24 axis. Gastrin inhibited GC growth and enhanced the suppression of GC by cisplatin in mice or PGC cell culture models through activating the ERK-P65-miR23a/27a/24 axis or its components.

CONCLUSIONS

ERK-P65-miR23a/27a/24 axis is down-regulated, leading to excess GC growth and poor prognosis of GC. Low gastrin promoted excess GC growth and contributed to the poor prognosis of the GC patients by down-regulating ERK-P65-miR23a/27a/24 axis. Gastrin inhibits gastric cancer growth through activating the ERK-P65-miR23a/27a/24 axis.

Circ-8073 regulates CEP55 by sponging miR-449a to promote caprine endometrial epithelial cells proliferation via the PI3K/AKT/mTOR pathway

Circular RNAs (circRNAs) are a large class of endogenous non-coding RNAs that function as regulators in various cells and tissues. Here, the function and mechanism of circRNA8073 (Circ-8073) on endometrial epithelial cells (EECs) and the development of endometrial receptivity were investigated in dairy goats. Circ-8073 could bind to and inhibit miR-449a activity. Circ-8073 binding to the target site of miR-449a had a negative feedback relationship. Centrosomal protein55 (CEP55) was a direct target gene of miR-449a, and Circ-8073 could increase the expression levels of CEP55 by sponging miR-449a in EECs in vitro. Circ-8073/miR-449a/CEP55 could promote EECs proliferation via the PI3K/AKT/mTOR pathway. In addition, CEP55 could regulate the expression levels of vascular endothelial growth factor (VEGF) and forkhead box M1 (FOXM1) in EECs, which contributed to the development of endometrial receptivity. These findings showed that Circ-8073 regulated CEP55 by sponging miR-449a to promote EEC proliferation via the PI3K/AKT/mTOR pathway, suggesting that it could function as a regulator in the development of endometrial receptivity in dairy goats.

MicroRNA-196b inhibits late apoptosis of pancreatic cancer cells by targeting CADM1

Pancreatic cancer (PC), as the leading cause of cancer death worldwide, is one of the deadliest tumors with a very low 5-year survival rate. Therefore, it is urgent to seek new biomarkers of PC for more accurate and reliable treatments. To identify the differentially expressed miRNAs (DEM) in PC tissues, we performed the systematic microarray and qRT-PCR analyses. We found miR-196b was the top dysregulated DEM in PC tissues as compared with the corresponding adjacent tissues, and positively correlated with poor differentiation, tumor size, lymphatic invasion and TNM stage. Furthermore, the late apoptosis rate was significantly reduced, while the cell proliferation was increased in PANC-1 and ASPC-1 cell-lines after treatment with miR-196b mimics. The qRT-PCR and Western blot analysis demonstrated that the level of CADM1 in PANC-1 cells response to the alteration of miR-196b. Moreover, blockade of CADM1 could decrease the late apoptosis in PANC-1 cells as up-regulated by inhibition of miR-196b. Finally, luciferase report assay confirmed that CADM1 was the direct target gene of miR-196b. Overexpression of miR-196b in PC tissues can increase the late apoptosis of pancreatic cancer cells by targeting CADM1. These findings suggested miR-196b is a potential target for diagnosis and therapeutics of human pancreatic cancer.

Aberrant DNA methylation in melanoma: biomarker and therapeutic opportunities

Aberrant DNA methylation is an epigenetic hallmark of melanoma, known to play important roles in melanoma formation and progression. Recent advances in genome-wide methylation methods have provided the means to identify differentially methylated genes, methylation signatures, and potential biomarkers. However, despite considerable effort and advances in cataloging methylation changes in melanoma, many questions remain unanswered.

The aim of this review is to summarize recent developments, emerging trends, and important unresolved questions in the field of aberrant DNA methylation in melanoma. In addition to reviewing recent developments, we carefully synthesize the findings in an effort to provide a framework for understanding the current state and direction of the field. To facilitate clarity, we divided the review into DNA methylation changes in melanoma, biomarker opportunities, and therapeutic developments. We hope this review contributes to accelerating the utilization of the diagnostic, prognostic, and therapeutic potential of DNA methylation for the benefit of melanoma patients.

The diagnostic effect of serum miR-196b as biomarker in colorectal cancer

The microRNA, miR-196b, serves a role in normal cell differentiation, proliferation and tumorigenesis of different types of cancer. The aim of the present study was to explore the serum expression of miR-196b in colorectal cancer (CRC) and its correlation with clinicopathological features. Sera samples were obtained from 103 patients with CRC, 51 patients with colorectal adenoma (Ad) and 100 healthy individuals for the present study. The serum expression of miR-196b in sera samples of the three cohorts was detected using reverse transcription-quantitative polymerase chain reaction. The diagnostic value of miR-196b in the serum of the patients with CRC was evaluated by receiver operating characteristic (ROC) curve and survival analysis, using the Kaplan-Meier method, which was performed with the data from a 5-year follow-up. The expression of miR-196b in the serum of patients with CRC was significantly higher compared with that in Ad patients or healthy individuals (all P<0.001), and the overexpression of serum miR-196b was clearly associated with lymph node invasion, differentiation, and the tumor-lymph nodes-metastasis stage (all P<0.05). ROC curve analysis demonstrated that, comparing patients with CRC with healthy individuals, the area under the curve of serum miR-196b was 0.8135, and its specificity and sensitivity were 63 and 87.38%, respectively, at a diagnostic threshold of −4.785. Patients with CRC of miR-196b-high status had shorter overall survival and disease-free survival rates compared with those of miR-196b-low status. In conclusion, the results of the present study demonstrated that serum miR-196b is upregulated in CRC, and may have an application as a diagnostic and prognostic biomarker for patients with CRC.

miR-30 functions as an oncomiR in gastric cancer cells through regulation of P53-mediated mitochondrial apoptotic pathway

The present study was designed to investigate the role of miR-30 in the development of Gastric cancer (GC). miR-30 expression was increased in GC tissues and cell lines. Downregulation of miR-30 inhibited cell proliferation and promoted apoptosis in HGC-27 cells. Upregulation of miR-30 enhanced the proliferation and inhibited apoptosis. P53 expression was decreased in GC tissues. P53 expression was correlated with miR-30 expression. Downregulation of miR-30 increased P53 expression. Knockdown of P53 inhibited miR-30-inhibitor-induced suppression of cell proliferation and increase of apoptosis. Downregulation of miR-30 increased ROS generation which was inhibited by shP53. miR-30 inhibitors induced a decrease in mitochondrial oxygen consumption, cytoplasmic release of cytochrome c, and activation of Caspase 3 and 9, activating mitochondrial apoptotic pathway. Downregulation of P53 and N-acetyl-cysteine suppressed miR-30 inhibitors-activated mitochondrial dysfunction and apoptotic events. In conclusion, we identified that miR-30 functioned as a potential oncomiR through P53/ROS-mediated regulation of mitochondrial apoptotic pathway.

Identification of microRNAs with Dysregulated Expression in Status Epilepticus Induced Epileptogenesis

The involvement of miRNA in mesial temporal lobe epilepsy (MTLE) pathogenesis has increasingly become a focus of epigenetic studies. Despite advances, the number of known miRNAs with a consistent expression response during epileptogenesis is still small. Addressing this situation requires additional miRNA profiling studies coupled to detailed individual expression analyses. Here, we perform a miRNA microarray analysis of the hippocampus of Wistar rats 24 hours after intra-hippocampal pilocarpine-induced Status Epilepticus (H-PILO SE). We identified 73 miRNAs that undergo significant changes, of which 36 were up-regulated and 37 were down-regulated. To validate, we selected 5 of these (10a-5p, 128a-3p, 196b-5p, 352 and 324-3p) for RT-qPCR analysis. Our results confirmed that miR-352 and 196b-5p levels were significantly higher and miR-128a-3p levels were significantly lower in the hippocampus of H-PILO SE rats. We also evaluated whether the 3 miRNAs show a dysregulated hippocampal expression at three time periods (0h, 24h and chronic phase) after systemic pilocarpine-induced status epilepticus (S-PILO SE). We demonstrate that miR-128a-3p transcripts are significantly reduced at all time points compared to the naïve group. Moreover, miR-196b-5p was significantly higher only at 24h post-SE, while miR-352 transcripts were significantly up-regulated after 24h and in chronic phase (epileptic) rats. Finally, when we compared hippocampi of epileptic and non-epileptic humans, we observed that transcript levels of miRNAs show similar trends to the animal models. In summary, we successfully identified two novel dysregulated miRNAs (196b-5p and 352) and confirmed miR-128a-3p downregulation in SE-induced epileptogenesis. Further functional assays are required to understand the role of these miRNAs in MTLE pathogenesis.

PRL-3 promotes the peritoneal metastasis of gastric cancer through the PI3K/Akt signaling pathway by regulating PTEN

Peritoneal metastasis is the most frequent cause of death in patients with advanced gastric carcinoma (GC). The phosphatase of regenerating liver-3 (PRL-3) is recognized as an oncogene and plays an important role in GC peritoneal metastasis. However, the mechanism of how PRL-3 regulates GC invasion and metastasis is unknown. In the present study, we found that PRL-3 presented with high expression in GC with peritoneal metastasis, but phosphatase and tensin homologue (PTEN) was weakly expressed. The p-PTEN/PTEN ratio was also higher in GC with peritoneal metastasis than that in the normal gastric tissues. We also found the same phenomenon when comparing the gastric mucosa cell line with the GC cell lines. After constructing a wild-type and a mutant-type plasmid without enzyme activity and transfecting them into GC SGC7901 cells, we showed that only PRL-3 had enzyme activity to downregulate PTEN and cause PTEN phosphorylation. The results also showed that PRL-3 increased the expression levels of MMP-2/MMP-9 and promoted the migration and invasion of the SGC7901 cells. Knockdown of PRL-3 decreased the expression levels of MMP-2/MMP-9 significantly, which further inhibited the migration and invasion of the GC cells. PRL-3 also increased the expression ratio of p-Akt/Akt, which indicated that PRL-3 may mediate the PI3K/Akt pathway to promote GC metastasis. When we transfected the PTEN siRNA plasmid into the PRL-3 stable low expression GC cells, the expression of p-Akt, MMP-2 and MMP-9 was reversed. In conclusion, our results provide a bridge between PRL-3 and PTEN; PRL-3 decreased the expression of PTEN as well as increased the level of PTEN phosphorylation and inactivated it, consequently activating the PI3K/Akt signaling pathway, and upregulating MMP-2/MMP-9 expression to promote GC cell peritoneal metastasis.

GLP-1 analogue improves hepatic lipid accumulation by inducing autophagy via AMPK/mTOR pathway

The incidence of nonalcoholic fatty liver disease (NAFLD) keeps rising year by year, and NAFLD is rapidly becoming the most common liver disease worldwide. Clinical studies have found that glucagon-like peptide-1 (GLP-1) analogue, liraglutide (LRG), cannot only reduce glucose levels, but also improve hepatic lipase, especially in patients also with type 2 diabetes mellitus (T2DM). In addition, enhancing autophagy decreases lipid accumulation in hepatocytes. The aim of the present study is to explore the effect of LRG on hepatocyte steatosis and the possible role of autophagy. We set up an obesity mouse model with a high-fat diet (HFD) and induced hepatocyte steatosis with free fatty acids (FFA) in human L-O2 cells. LRG and two inhibitors of autophagy, Chloroquine (CQ) and bafilomycin A1 (Baf), were added into each group, respectively. The lipid profiles and morphological modifications of each group were tested. Immunohistochemistry, immunofluorescence staining and transmission electron microscopy (TEM) were used to measure autophagy in this study. The autophagy protein expression of SQSTM1 (P62), and LC3B, along with the signaling pathway proteins of mTOR, phosphorylated mTOR (p-mTOR), AMPK, phosphorylated AMPK (p-AMPK) and Beclin1, were evaluated by western blot. Our results showed that LRG improved hepatocyte steatosis by inducing autophagy, and the AMPK/mTOR pathway is involved. These findings suggest an important mechanism for the positive effects of LRG on hepatic steatosis, and provide new evidence for clinical use of LRG in NAFLD.