MiRNA-615-5p functions as a tumor suppressor in pancreatic ductal adenocarcinoma by targeting AKT2. PLoS One. 2015;10:e0119783. [PMID: 25856297 PMCID: PMC4391776 DOI: 10.1371/journal.pone.0119783]

Pro-inflammatory Cytokines Promote the Occurrence and Development of Colitis-associated Colorectal Cancer by Inhibiting miR-615-5p

BACKGROUND

Patients with ulcerative colitis (UC) may be prone to colitis-associated colorectal cancer (CAC), but there is still a poor understanding of the underlying mechanism so far. This study intended to clarify the role of pro-inflammatory cytokines and miR-615-5p in this process.

METHODS

This experiment first detected miR-615-5p expressions in paraffin-embedded sections of colonic tissues from patients with UC and CAC. Then, we investigated the mechanism through which pro-inflammatory cytokines affected miR-615-5p. Furthermore, in vivo and in vitro tests were performed to identify how miR-615-5p affected colorectal cancer (CRC). Dual-luciferase reporter assay was then employed to identify the targeting relationship between miR-615-5p and stanniocalcin-1 (STC1).

RESULTS

The miR-615-5p was lowly expressed in both cancerous and noncancerous colonic tissues of patients with CAC. Pro-inflammatory cytokines downregulated miR-615-5p expression. Overexpression of miR-615-5p reduced the proliferation and migration of CRC cells and had a certain therapeutic effect on in human CRC xenograft mice. Stanniocalcin-1 was identified to be a target gene of miR-615-5p and was involved in the effect of miR-615-5p on CRC.

CONCLUSIONS

During the progression from UC to CAC, pro-inflammatory cytokines downregulate miR-615-5p, which may induce the upregulation of STC1, and promote the occurrence and development of tumors. These findings offer new insights into the mechanism of CAC and may indicate novel tumor markers or therapeutic targets.

Transcription factor ETV1-induced lncRNA MAFG-AS1 promotes migration, invasion, and epithelial-mesenchymal transition of pancreatic cancer cells by recruiting IGF2BP2 to stabilize ETV1 expression

We investigated the mechanism of ETS-translocation variant 1 (ETV1)/lncRNA-MAFG-AS1 in pancreatic cancer (PC). MAFG-AS1 and ETV1 levels in PC cell lines and HPNE cells were determined using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting (WB). After transfection with sh-MAFG-AS1, PC cell invasion, migration, proliferation, and epithelial-mesenchymal transition (EMT)-related proteins were measured by 5-ethynyl-2'-deoxyuridine (EdU), Transwell assay, and WB. The binding between ETV1 and MAFG-AS1 was studied using dual-luciferase assay and chromatin immunoprecipitation. The interactions between MAFG-AS1, IGF2BP2, and ETV1 were tested. Combined experiments were further performed using sh-MAFG-AS1 and pcDNA-ETV1 simultaneously. ETV1/MAFG-AS1 was highly expressed in PC cells. Blocking MAFG-AS1 inhibited the malignant behaviors of PC cells. ETV1 induced MAFG-AS1 transcription in PC cells. MAFG-AS1 stabilized ETV1 mRNA by recruiting IGF2BP2. ETV1 overexpression partially antagonized the suppression of silencing MAFG-AS1 on PC cells. ETV1-induced MAFG-AS1 stabilized the ETV1 expression by recruiting IGF2BP2 and promoted PC cell migration, invasion, proliferation, and EMT.

Mechanism of human chorionic gonadotropin in endometrial receptivity via the miR-126-3p/PI3K/Akt/eNOS axis

Human chorionic gonadotropin (hCG) might affect endometrial receptivity, exerting integral roles in embryo implantation. This study explored the action of hCG in endometrial receptivity via the miR-126-3p/PIK3R2/PI3K/Akt/eNOS axis. The embryo implantation dysfunction (EID) mouse models were established by administrating mifepristone and human endometrial epithelial cells (EECs) were used for in vivo experiments, both followed by hCG treatment. Expression level of CD105 and protein levels of cadherin CD144 and CD146 in mice were determined by immunohistochemistry and Western blot. The levels of miR-126-3p and PIK3R2 mRNA and PIK3R2, p-PI3K p85 α, PI3K p110 α, p-Akt, Akt, p-eNOS, and eNOS protein levels were measured. Cell proliferation was evaluated by CCK-8 and EdU assays. The binding sites of miR-126-3p and PIK3R2 were predicted and verified. hCG-treated EECs were further transfected with miR-126-inhibitor for functional rescue experiments. hCG ameliorated endometrial receptivity in EID mice. Moreover, hCG promoted miR-126-3p and suppressed PIK3R2 in EID mice and EECs. miR-126-3p targeted PIK3R2. EEC proliferation was enhanced after hCG treatment but inhibited by miR-126-3p downregulation. Both in vivo and in vitro experiments validated that hCG activated the PI3K/Akt/eNOS pathway through the miR-126-3p/PIK3R2 axis. Collectively, hCG improves endometrial receptivity by activating the PI3K/Akt/eNOS pathway via regulating miR-126-3p/PIK3R2.

Hydroxyacid Oxidase 2 (HAO2) Inhibits the Tumorigenicity of Hepatocellular Carcinoma and Is Negatively Regulated by miR-615-5p

Background

Hepatocellular carcinoma (HCC) is the sixth most common kind of cancer worldwide and the third leading cause of cancer mortality. Although a few studies have shown that hydroxyacid oxidase 2 (HAO2) may prevent HCC development, the molecular mechanism is unclear.

Methods

We examined the levels of HAO2 expression in 23 pairs of HCC/paracancerous tissues by quantitative real-time polymerase chain reaction (qRT-PCR) and evaluated HAO2's expression in The Cancer Genome Atlas (TCGA) database. Furthermore, we examined the biological activity of HAO2 utilizing cell-based functional assays. Additionally, we evaluated the relationship between miR-615-5p and HAO2 in Hep3B cells using a dual-luciferase reporter system and assessed the downstream regulatory mechanisms of miR-615-5p on HAO2. Finally, the nude mice tumor formation experiment was used to determine the impact of HAO2 on the tumorigenicity of HCC cells.

Results

HAO2 expression was considerably underexpression in HCC tissues and cells, and patients with low HAO2 expression had poorer disease-free survival. Inhibition of cell proliferation, migration, and invasion was observed when HAO2 was overexpressed. miR-615-5p had a negative relation with HAO2, and miR-615-5p restored HAO2's biological activity in HCC cells. Additionally, the tumor volume and weight were considerably reduced in the OV-HAO2 group compared to the OV-NC group.

Conclusion

HAO2 was found to be underexpressed in HCC tissues and cells, and HAO2 overexpression inhibited HCC cell motility, which was negatively regulated by miR-615-5p. Exogenous expression of HAO2 reduced the tumorigenicity of HCC cells in vivo in nude mice.

Circular RNA hsa_circ_0004396 acts as a sponge of miR-615-5p to promote non-small cell lung cancer progression and radioresistance through the upregulation of P21-Activated Kinase 1

BACKGROUNDS

CircRNA hsa_circ_0004396 has been confirmed to be upregulated in human non-small cell lung cancer (NSCLC). The aim of his study was to evaluate its mechanism in the radioresistance and progression of NSCLC.

METHODS

Hsa_circ_0004396, miR-615-5p, and P21-Activated Kinase 1 (PAK1) were measured by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). The binding between miR-615-5p and hsa_circ_0004396 or PAK1 was predicted by circinteractome or Targetscan, as verified by dual-luciferase reporter assay and RIP assay. Proliferation, clonogenicity capacity, cell cycle progression, apoptosis, migration, and invasion were assessed by CCK-8, colony formation, flow cytometry, and Transwell assay. Bcl-2, Bcl-2 associated protein X (Bax), MMP-2, and PAK1 protein levels were detected using western blot assay. In addition, in vivo function of hsa_circ_0004396 was evaluated by tumor xenograft assay.

RESULTS

Hsa_circ_0004396 and PAK1 levels were upregulated, while miR-615-5p was declined in NSCLC. Hsa_circ_0004396 silencing inhibited NSCLC cell malignant behavior and induced radiosensitivity. Hsa_circ_0004396 functions as a molecular sponge of miR-615-5p to regulate PAK1 expression. Moreover, hsa_circ_0004396 knockdown inhibited NSCLC tumor growth in vivo.

CONCLUSION

Our findings demonstrated that hsa_circ_0004396 promoted NSCLC development and radioresistance through the miR-615-5p/PAK1 axis, which might provide a new therapeutic target for NSCLC treatment.

Hsa_circRNA_002144 promotes growth and metastasis of colorectal cancer through regulating miR-615-5p/LARP1/mTOR pathway

CircRNAs (circular RNAs), recently identified as a critical regulator in tumorigenesis, participate in CRC (colorectal cancer) growth. However, the role of hsa_circRNA_002144 in CRC was poorly understood. Firstly, hsa_circRNA_002144 showed significantly elevation in both of CRC tissues and cell lines, and suggested closely associated with poor prognosis in patients. Secondly, data from functional assays revealed that silence of hsa_circRNA_002144 inhibited CRC progression with reduced cell viability, proliferation, migration and invasion, while enhanced cell apoptosis. In addition, in vivo CRC growth and metastasis were also suppressed by knockdown of hsa_circRNA_002144. However, CRC progression was promoted with over-expression of hsa_circRNA_002144. Thirdly, hsa_circRNA_002144 colocalized with miR-615-5p in the cytoplasm of CRC cells, and decreased miR-615-5p expression. Moreover, miR-615-5p could target LARP1 (La ribonucleoprotein 1, translational regulator). Lastly, the suppressive effects of hsa_circRNA_002144 knockdown on CRC progression were reversed by LARP1 over-expression. In conclusion, hsa_circRNA_002144 could sponge miR-615-5p to promote CRC progression through the regulation of LARP1, providing a therapeutic target for cancer intervention.

How metformin affects various malignancies by means of microRNAs: a brief review

Metformin known as the first-line orally prescribed drug for lowering blood glucose in type II diabetes (T2DM) has recently found various therapeutic applications including in cancer. Metformin has been studied for its influences in prevention and treatment of cancer through multiple mechanisms such as microRNA (miR) regulation. Alteration in the expression of miRs by metformin may play an important role in the treatment of various cancers. MiRs are single-stranded RNAs that are involved in gene regulation. By binding to the 3'UTR of target mRNAs, miRs influence protein levels. Irregularities in the expression of miRs that control the expression of oncogenes and tumor suppressor genes are associated with the onset and progression of cancer. Metformin may possess an effect on tumor prevention and progression by modifying miR expression and downstream pathways. Here, we summarize the effect of metformin on different types of cancer by regulating the expression of various miRs and the associated downstream molecules.

CircRNA circ-OGDH (hsa_circ_0003340) Acts as a ceRNA to Regulate Glutamine Metabolism and Esophageal Squamous Cell Carcinoma Progression by the miR-615-5p/PDX1 Axis

Background

Circular RNA hsa_circ_0003340 (circ-OGDH) has been uncovered to be involved in esophageal squamous cell carcinoma (ESCC) progression. However, the mechanism by which circ-OGDH regulates ESCC progression is unclear.

Methods

Expression levels of circ-OGDH, microRNA (miR)-615-5p, and PDX1 (pancreatic and duodenal homeobox 1) mRNA were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, apoptosis, migration, invasion, and cell cycle progression of ESCC cells were analyzed by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide), colony formation, flow cytometry, and transwell assays. Measurement of glutamine consumption, α-KG (α-ketoglutarate) production, and ATP (Adenosine Triphosphate) content using corresponding kits. Protein levels were analyzed by Western blotting. The targeting relationship between circ-OGDH or PDX1 and miR-615-5p was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The function of circ-OGDH in ESCC was confirmed by animal experiments.

Results

Circ-OGDH was upregulated in ESCC. Circ-OGDH inhibition reduced ESCC growth in vivo and accelerated cell apoptosis, cell cycle arrest, repressed cell proliferation, migration, invasion, and reduced cell glutamine metabolism in ESCC cells in vitro. MiR-615-5p was downregulated in ESCC, while PDX1 had an opposite result. Circ-OGDH sponged miR-615-5p to regulate PDX1 expression. MiR-615-5p inhibitor neutralized the repressive effect of circ-OGDH knockdown on malignancy and glutamine metabolism of ESCC cells. PDX1 overexpression counteracted the inhibitory impact of miR-615-5p mimic on malignancy and glutamine metabolism of ESCC cells.

Conclusion

Circ-OGDH sponged miR-615-5p to elevate PDX1 expression, thus elevating glutamine metabolism and promoting tumor growth in ESCC. The study offered evidence to support circ-OGDH as a promising target for ESCC therapy.

Effects of microRNA-103 on the Proliferation and Apoptosis of Pancreatic Cancer Cells via Targeting Phosphatase and Tensin Homolog Deleted on Chromosome Ten (PTEN) and Activating Phosphoinositide 3-Kinase/A Serine/Threonine Kinase (PI3K/Akt) Signaling Pathway

Objective: To investigate whether micro ribonucleic acid (miR)-103 affects pancreatic cancer (PaCa) cells via PTEN-activated PI3K/Akt signaling pathway. Methods: Differences in miR-103 expression in 35 pairs of PaCa tissues and cell lines (SW1990 and PATU8988S) were detected by RT-qPCR. miR-103 inhibitor was transfected into PaCa PATU8988S cell followed by analysis of proliferation and apoptosis of PaCa cells by MTT assay and flow cytometry, respectively. Results: MiR-103 exhibited a significantly high expression in PaCa tissues and cell lines (p < 0.05). Besides, the exogenous inhibition of miR-103 expression in PATU8988S cells significantly inhibited cell proliferation and migration but increased apoptosis activity (p < 0.05). According to the prediction of TargetScan biological database, miR-103 could bind PTEN 3′ untranslated region (3′UTR) and miR-103 was confirmed to suppress PTEN expression in a targeted way (p<0.05). Furthermore, down-regulation of PTEN activated PI3K/Akt signaling to affect the proliferation and apoptosis of PaCa cells (p < 0.05 or p <0.01). Conclusion: MiR-103 displays a significantly increased expression in PaCa cells and targets PTEN to activate PI3K/Akt signaling pathway, thus promoting malignant phenotype formation.

MicroRNA-615-5p regulates the proliferation and apoptosis of breast cancer cells by targeting HSF1

Breast cancer, which commonly occurs in the epithelium of the mammary gland, is a malignant tumor. MicroRNAs are involved in various cancer-associated processes, and microRNA-615-5p has been identified to be decreased in the pathological tissues from patients with breast cancer. In the present study, the possible mechanism of microRNA-615-5p in the progression of breast cancer was investigated in order to identify potential novel targets for clinical treatment. Heat shock factor 1 (HSF1) was identified as a predictive target gene of microRNA-615-5p using TargetScan analysis. The expression levels of microRNA-615-5p and its target gene, HSF1, were measured in breast cancer tissues and normal adjacent tissues. Additionally, the effects of microRNA-615-5p on MCF-7 breast cancer cell growth and apoptosis were examined. Furthermore, the interaction between HSF1 and microRNA-615-5p was investigated by a dual luciferase gene reporter assay. The expression levels of HSF1 were measured following transfection with microRNA-615-5p or pcDNA3.1-HSF1. Finally, the expression levels of proliferation- and apoptosis-associated factors such as B-cell lymphoma 2 (Bcl-2), cyclin D1, proliferating cell nuclear antigen (PCNA) and bcl-2-like protein 4 (Bax) were determined. The results demonstrated that lower microRNA-615-5p expression and higher HSF1 mRNA expression were present in tumor tissues compared with adjacent tissues (P<0.01). HSF1 was verified as a direct target of microRNA-615-5p using the dual luciferase gene reporter assay. In comparison with untransfected control and mimic-transfected negative control (NC) cells, MCF-7 cells transfected with microRNA-615-5p mimics exhibited reduced cell proliferation and increased apoptosis (P<0.01). However, the overexpression of HSF1 using a vector reversed the suppression of HSF1 induced by microRNA-615-5p mimics (P<0.01). The mRNA and protein expression levels of Bax were significantly increased, whereas those of Bcl-2, cyclin D1 and PCNA were decreased in the cells transfected with microRNA-615-5p mimics compared with the control and NC cells (P<0.01). Collectively, the present study indicated that microRNA-615-5p may mediate the progression of breast cancer by targeting HSF1.

MiRNAs directly targeting the key intermediates of biological pathways in pancreatic cancer

Pancreatic Cancer (PC) is a severe form of malignancy all over the world. Delayed diagnosis and chemoresistance are the major factors contributing to its poor prognosis and high mortality rate. The genetic and epigenetic regulations of biological pathways further complicate the progression and chemotherapy response to this cancer. MicroRNAs (MiRNAs) involvement has been observed in all types of cancers including PC. The understanding and categorization of miRNAs according to their specific targets are very important to develop early diagnostic and therapeutic interventions. The current review, emphasizing recent research findings, has categorized miRNAs that directly target the potential onco-factors that act as central converging signal-nodes in five major cancer-related pathways i.e., MAPK/ERK, JAK/STAT, Wnt/β-catenin, AKT/mTOR, and TGFβ in PC. The therapeutic perspectives of miRNAs in PC have also been discussed. This will help to understand the interplay of various miRNAs within foremost signaling pathways and develop a multifactorial approach to treat difficult-to-treat PC.

Vav1 Down-Modulates Akt2 Expression in Cells from Pancreatic Ductal Adenocarcinoma: Nuclear Vav1 as a Potential Regulator of Akt Related Malignancy in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive tumor malignancy worldwide, mainly due to uncontrolled metastasis. Among the numerous molecules deregulated in PDAC, different members of the Akt pathways are of great importance because they are involved in tumor cell proliferation, migration, and invasion. We have recently demonstrated that Vav1, ectopically expressed in solid tumors, is capable of down-modulating expression and/or activation of specific Akt isoforms in breast cancer cells. By using pancreatic cell lines expressing different basal levels of Vav1, we demonstrated here that Vav1 down-regulates the expression of Akt2, known to correlate with tumor metastases and resistance to therapy. In particular, while the silencing of Vav1 is sufficient to induce Akt2, its up-modulation reduces Akt2 levels only when Vav1 accumulates inside the nucleus of PDAC cells. Moreover, in PDAC tissues, we revealed that high nuclear levels of Vav1 correlate with low Akt2 expression. Although we cannot demonstrate the mechanisms involved, our results provide new insights into the role of Vav1 in PDAC and, as targeting specific members of the Akt family is a promising therapeutic chance in solid tumors, they suggest that Vav1, by down-modulating Akt2, has potential as a molecular target in PDAC.

Long Non-Coding RNAs as Strategic Molecules to Augment the Radiation Therapy in Esophageal Squamous Cell Carcinoma

Intrinsic resistance to ionizing radiation is the major impediment in the treatment and clinical management of esophageal squamous cell carcinoma (ESCC), leading to tumor relapse and poor prognosis. Although several biological and molecular mechanisms are responsible for resistance to radiotherapy in ESCC, the molecule(s) involved in predicting radiotherapy response and prognosis are still lacking, thus requiring a detailed understanding. Recent studies have demonstrated an imperative correlation amongst several long non-coding RNAs and their involvement in complex cellular networks like DNA damage and repair, cell cycle, apoptosis, proliferation, and epithelial-mesenchymal transition. Additionally, accumulating evidence has suggested abnormal expression of lncRNAs in malignant tumor cells before and after radiotherapy effects in tumor cells' sensitivity. Thus, lncRNAs indeed represent unique molecules that can influence tumor cell susceptibility for various clinical interventions. On this note, herein, we have summarized the current status of lncRNAs in augmenting resistance/sensitivity in ESCC against radiotherapy. In addition, we have also discussed various strategies to increase the radiosensitivity in ESCC cells under clinical settings.

miR-615 Fine-Tunes Growth and Development and Has a Role in Cancer and in Neural Repair

MicroRNAs (miRNAs) are small noncoding RNAs that function as epigenetic modulators regulating almost any gene expression. Similarly, other noncoding RNAs, as well as epigenetic modifications, can regulate miRNAs. This reciprocal interaction forms a miRNA-epigenetic feedback loop, the deregulation of which affects physiological processes and contributes to a great diversity of diseases. In the present review, we focus on miR-615, a miRNA highly conserved across eutherian mammals. It is involved not only during embryogenesis in the regulation of growth and development, for instance during osteogenesis and angiogenesis, but also in the regulation of cell growth and the proliferation and migration of cells, acting as a tumor suppressor or tumor promoter. It therefore serves as a biomarker for several types of cancer, and recently has also been found to be involved in reparative processes and neural repair. In addition, we present the pleiad of functions in which miR-615 is involved, as well as their multiple target genes and the multiple regulatory molecules involved in its own expression. We do this by introducing in a comprehensible way the reported knowledge of their actions and interactions and proposing an integral view of its regulatory mechanisms.

Prognostic value of microRNAs in pancreatic cancer: a meta-analysis

BACKGROUND

The prognostic impact of microRNA (miRNA) expression levels in pancreatic cancer (PC) has been estimated for years, but the outcomes are controversial and heterogeneous. Therefore, we comprehensively reviewed the evidence collected on miRNA expression in PC to determine this effect.

RESULTS

PC patients with high miR-21 (HR=2.61, 95%CI=1.68-4.04), miR-451a (HR=2.23, 95%CI=1.23-4.04) or miR-1290 (HR=1.43, 95%CI=1.04-1.95) levels in blood had significantly poorer OS (P<0.05). Furthermore, PC patients with high miR-10b (HR=1.73, 95%CI=1.09-2.76), miR-17-5p (HR=1.91, 95%CI=1.30-2.80), miR-21 (HR=1.90, 95%CI=1.61-2.25), miR-23a (HR=2.18, 95%CI=1.52-3.13), miR-155 (HR=2.22, 95%CI=1.27-3.88), miR-203 (HR=1.65, 95%CI=1.14-2.40), miR-221 (HR=1.72, 95%CI=1.08-2.74), miR-222 levels (HR=1.72, 95%CI=1.02-2.91) or low miR-29c (HR=1.39, 95%CI=1.08-1.79), miR-126 (HR=1.55, 95%CI=1.23-1.95), miR-218 (HR=2.62, 95%CI=1.41-4.88) levels in tissues had significantly shorter OS (P<0.05).

CONCLUSIONS

In summary, blood miR-21, miR-451a, miR-1290 and tissue miR-10b, miR-17-5p, miR-21, miR-23a, miR-29c, miR-126, miR-155, miR-203, miR-218, miR-221, miR-222 had significant prognostic value.

METHODS

We searched PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews to recognize eligible studies, and 57 studies comprising 5445 PC patients and 15 miRNAs were included to evaluate the associations between miRNA expression levels and overall survival (OS) up to June 1, 2019. Summary hazard ratios (HR) with 95% confidence intervals (CI) were calculated to assess the effect.

Pancreatic Ductal Adenocarcinoma: MicroRNAs Affecting Tumor Growth and Metastasis in Preclinical In Vivo Models

Patients with pancreatic ductal adenocarcinoma have a dismall prognosis because at the time of diagnosis, in the vast majority of patients the tumor has already disseminated to distant organs and the therapeutic benefit of approved agents such as gemcitabine is limited. Therefore, the identification and preclinical and clinical validation of therapeutic agents covering new targets is of paramount importance. In this review we have summarized microRNAs and corresponding targets which affect growth and metastasis of pancreatic tumors in preclinical mouse in vivo models. We identified four up-regulated and 16 down-regulated miRs in PDAC in comparison to corresponding normal tissues. Three sub-categories of miRs have emerged: miRs affecting tumor growth and miRs with an impact on both, tumor growth and metastasis or metastasis only. Finally, we discuss technical and therapeutic aspects of miR-related therapeutic agents for the treatment of pancreatic ductal adenocarcinoma.

circPUM1 Promotes Tumorigenesis and Progression of Ovarian Cancer by Sponging miR-615-5p and miR-6753-5p

Circular RNAs (circRNAs) have been reported to participate in the molecular mechanism of human cancers. The PUM1 gene has been confirmed to be closely related to tumorigenesis and progression of ovarian cancer. In the present study, we explored the function and underlying molecular mechanism of circPUM1 in ovarian cancer. qRT-PCR analysis showed upregulation of circPUM1 in ovarian cancer tissues compared with normal ovaries. Gain- and loss-of-function experiments indicated that circPUM1 increased cell proliferation, migration, and invasion and inhibited cell apoptosis. Intraperitoneal injection of circPUM1-knockout tumor cells in nude mice resulted in a decrease in the metastatic ability of the tumor. Bioinformatics analysis and dual-luciferase reporter assays revealed that circPUM1 upregulated the expression of nuclear factor kappa B (NF-κB) and MMP2 by sponging miR-615-5p and miR-6753-5p. Further studies showed that exosomal circPUM1 acted on peritoneal mesothelial cells and increased tumor metastasis. In conclusion, our study indicates that circPUM1 not only promotes ovarian cancer proliferation, migration and invasion, but also acts on the peritoneum and contributes to metastasis of cancer in the form of cancer-derived exosomes.

miR-557 inhibits the proliferation and invasion of pancreatic cancer cells by targeting EGFR

Deregulation of microRNA has been suggested as a critical event in pancreatic cancer development and progression. Thus far, very little is known about the role of miR-557; therefore, the goal of this study was to investigate the potential role of miR-557 in pancreatic cancer. In the present study, we discovered that miR-557 expression was lowered in cancerous pancreatic tissue samples relative to non-cancerous adjacent controls, and when miR-557 was overexpressed we found that this promoted the apoptotic death of pancreatic cancer cells, suppressing their proliferation, invasion, and migration. Using western blotting and luciferase reporter assays, we further found evidence that this miRNA may directly suppress expression of the epidermal growth factor receptor via suppressing its translation through 3'-UTR binding. When EGFR was overexpressed in our pancreatic cancer cells, this was sufficient to reverse the effects of miR-557 inhibition. In summary, miR-557 acts as a tumor suppressor in pancreatic cancer cells, impairing their ability to grow and invade surrounding tissues due at least in part to EGFR inhibition. Harnessing this targeting of EGFR via this miRNA may therefore be a viable strategy useful for patient suffering from this deadly disease.

Gain of microRNA-103 triggers metastatic behavior by targeting ubiquitin specific peptidase 10 in pancreatic cancer

Emerging studies have shown that microRNAs (miRNAs) play key roles in regulating progression of pancreatic cancer (PaCa). miR-103 has been reported to serve as an oncomiR in hepatocellular carcinoma and colorectal cancer. However, litter is known regarding the function and molecular mechanism of miR-103 in PaCa. Here, we observed that miR-103 was markedly highly expressed in PaCa tissues and cell lines. Up-regulation of miR-103 expression was associated with advanced TNM stage, positive lymph node metastasis, and poor prognosis. Furthermore, knock-down of miR-103 by its inhibitor resulted in inhibited cell invasion and migration. Using a dual-luciferase reporter assay, we identified that USP10 (Ubiquitin specific peptidase 10) was a directly target of miR-103. In addition, by using qRT-PCR assay and western blotting analysis, we found that miR-103 down-regulated the expression of USP10 in PaCa tissues and cell lines. Taken together, the present study demonstrates that up-regulation of miR-103 is associated with tumor metastasis and poor prognosis in PaCa patients. Our data further indicates that miR-103 is an upregulated oncomiR and promotes cell metastasis by targeting USP10, suggesting miR-103 may be a potential prognosis and treatment target for PaCa.

Entamoeba histolytica Up-Regulates MicroRNA-643 to Promote Apoptosis by Targeting XIAP in Human Epithelial Colon Cells

MicroRNAs (miRNAs) are small non-coding RNAs that function as negative regulators of gene expression. Recent evidences suggested that host cells miRNAs are involved in the progression of infectious diseases, but its role in amoebiasis remains largely unknown. Here, we reported an unexplored role for miRNAs of human epithelial colon cells during the apoptosis induced by Entamoeba histolytica. We demonstrated for the first time that SW-480 colon cells change their miRNAs profile in response to parasite exposure. Our data showed that virulent E. histolytica trophozoites induced apoptosis of SW-480 colon cells after 45 min interaction, which was associated to caspases-3 and -9 activation. Comprehensive profiling of 667 miRNAs using Taqman Low-Density Arrays showed that 6 and 15 miRNAs were significantly (FC > 1.5; p < 0.05) modulated in SW-480 cells after 45 and 75 min interaction with parasites, respectively. Remarkably, no significant regulation of the 6-miRNAs signature (miR-526b-5p, miR-150, miR-643, miR-615-5p, miR-525, and miR-409-3p) was found when SW-480 cells were exposed to non-virulent Entamoeba dispar. Moreover, we confirmed that miR-150, miR-643, miR-615-5p, and miR-525 exhibited similar regulation in SW-480 and Caco2 colon cells after 45 min interaction with trophozoites. Exhaustive bioinformatic analysis of the six-miRNAs signature revealed intricate miRNAs-mRNAs co-regulation networks in which the anti-apoptotic XIAP, API5, BCL2, and AKT1 genes were the major targets of the set of six-miRNAs. Of these, we focused in the study of functional relationships between miR-643, upregulated at 45 min interaction, and its predicted target X-linked inhibitor of apoptosis protein (XIAP). Interestingly, interplay of amoeba with SW-480 cells resulted in downregulation of XIAP consistent with apoptosis activation. More importantly, loss of function studies using antagomiRs showed that forced inhibition of miR-643 leads to restoration of XIAP levels and suppression of both apoptosis and caspases-3 and -9 activation. Congruently, mechanistic studies using luciferase reporter assays confirmed that miR-643 exerts a postranscripcional negative regulation of XIAP by targeting its 3′-UTR indicating that it's a downstream effector. In summary, we provide novel lines of evidence suggesting that early-branched eukaryote E. histolytica may promote apoptosis of human colon cells by modulating, in part, the host microRNome which highlight an unexpected role for miRNA-643/XIAP axis in the host cellular response to parasites infection.

Molecular targets regulating invasion and metastasis of pancreatic cancer

Pancreatic cancer is one of the most malignant tumors of the digestive system. Invasion and metastasis are important biological characteristics of pancreatic cancer and contribute greatly to the poor prognosis of the patients. Many lines of evidence have recently revealed that many molecules, genes and proteins regulate the invasion and metastasis of pancreatic cancer cells. Therefore, exploration and a deep understanding of the molecular mechanism accounting for the invasion and metastasis of pancreatic cancer can help find novel pancreatic cancer biomarkers, improve early diagnosis, develop novel and effective treatment strategies, and predict the prognosis. This review summarizes the latest progress in the research of molecular targets for pancreatic cancer and the mechanisms by which they participate in the invasion and metastasis of this aggressive malignancy.

MiR-490-3p Functions As a Tumor Suppressor by Inhibiting Oncogene VDAC1 Expression in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide, usually with poor prognosis because many CRC patients are diagnosed at an advanced stage. Therefore, novel potential diagnostic and prognostic biomarkers are urgently needed. MicroRNAs have been reported to regulate a variety of biological processes, such as cell proliferation, differentiation and apoptosis. Accumulating studies have demonstrated that miR-490-3p could regulate the development and progression of multiple cancers, but its clinical significance and molecular mechanism in CRC are still elusive. Here, we try to further elucidate the regulatory mechanism of miR-490-3p in CRC. In the present study, miR-490-3p expression level observably down-regulated in CRC tissues and cell lines, and miR-490-3p expression in CRC tissues was significantly associated with TNM stage, histological grade, tumor size and overall survival (OS). In addition, we observed miR-490-3p expression was also decreased in CRC plasmas and could act as a promising diagnostic biomarker for screening CRC. Further studies in vitro demonstrated Voltage Dependent Anion Channel 1 (VDAC1) which highly expressed in CRC tissues and cell lines is a direct target of miR-490-3p, and miR-490-3p could markedly inhibit CRC cells proliferation, metastasis, invasion and anti-apoptosis through suppressing VDAC1/AMPK/mTOR pathway. These results indicated that miR-490-3p functions as a tumor suppressor in CRC, and may be a novel potential diagnostic and prognostic biomarker for CRC.

Network analysis based on TCGA reveals hub genes in colon cancer

Colorectal cancer (CRC) is the third most widespread cancer in the world. Although many advances have been made in molecular biology, novel approaches are still required to reveal molecular mechanisms for the diagnosis and therapy of colon cancer. In this study, we aimed to determine and analyse the hub genes of CRC. First, we explored the mRNA and microRNA (miRNA) expression profiles of colon carcinoma, then we screened target genes of differentially expressed miRNAs and obtained the intersection between differently expressed genes and target genes. Gene Ontology (GO) classification and KEGG pathway analysis of differently expressed genes were performed, and gene-miRNA and TF-gene-miRNA networks were constructed to identify hub genes, miRNAs, and TFs. In total, 3436 significant differentially expressed genes (1709 upregulated and 1727 downregulated) and 216 differentially expressed miRNAs (99 upregulated and 117 downregulated) were identified in colon cancer. These differentially expressed genes were significantly enriched in GO terms and KEGG pathways, such as cell proliferation, cell adhesion, and cytokine-cytokine receptor interaction signalling pathways. GCNT4, EDN2, and so on were located in the central hub of the co-expression network. MYC, WT1, mir-34a, and LEF1 were located in the central hub of the network of TF-gene-miRNA. These findings increase our understanding of the molecular mechanisms of colon cancer and will aid in identifying potential targets for diagnostic and therapeutic usage.

miRNA-148a serves as a prognostic factor and suppresses migration and invasion through Wnt1 in non-small cell lung cancer

Lung cancer is the leading cause of cancer death in the world, and aberrant expression of miRNA is a common feature during the cancer initiation and development. Our previous study showed that levels of miRNA-148a assessed by quantitative real-time polymerase chain reaction (qRT-PCR) were a good prognosis factor for non-small cell lung cancer (NSCLC) patients. In this study, we used high-throughput formalin-fixed and paraffin-embedded (FFPE) lung cancer tissue arrays and in situ hybridization (ISH) to determine the clinical significances of miRNA-148a and aimed to find novel target of miRNA-148a in lung cancer. Our results showed that there were 86 of 159 patients with low miRNA-148a expression and miRNA-148a was significantly down-regulated in primary cancer tissues when compared with their adjacent normal lung tissues. Low expression of miRNA-148a was strongly associated with high tumor grade, lymph node (LN) metastasis and a higher risk of tumor-related death in NSCLC. Lentivirus mediated overexpression of miRNA-148a inhibited migration and invasion of A549 and H1299 lung cancer cells. Furthermore, we validated Wnt1 as a direct target of miRNA-148a. Our data showed that the Wnt1 expression was negatively correlated with the expression of miRNA-148a in both primary cancer tissues and their corresponding adjacent normal lung tissues. In addition, overexpression of miRNA-148a inhibited Wnt1 protein expression in cancer cells. And knocking down of Wnt-1 by siRNA had the similar effect of miRNA-148a overexpression on cell migration and invasion in lung cancer cells. In conclusion, our results suggest that miRNA-148a inhibited cell migration and invasion through targeting Wnt1 and this might provide a new insight into the molecular mechanisms of lung cancer metastasis.

Validation of suitable normalizers for miR expression patterns analysis covering tumour heterogeneity

Oncogenic microRNAs (miRs) have emerged as diagnostic biomarkers and novel molecular targets for anti-cancer drug therapies. Real-time quantitative PCR (qPCR) is one of the most powerful techniques for analyzing miRs; however, the use of unsuitable normalizers might bias the results. Tumour heterogeneity makes even more difficult the selection of an adequate endogenous normalizer control. Here, we have evaluated five potential referenced small RNAs (U6, rRNA5s, SNORD44, SNORD24 and hsa-miR-24c-3p) using RedFinder algorisms to perform a stability expression analysis in i) normal colon cells, ii) colon and breast cancer cell lines and iii) cancer stem-like cell subpopulations. We identified SNORD44 as a suitable housekeeping gene for qPCR analysis comparing normal and cancer cells. However, this small nucleolar RNA was not a useful normalizer for cancer stem-like cell subpopulations versus subpopulations without stemness properties. In addition, we show for the first time that hsa-miR-24c-3p is the most stable normalizer for comparing these two subpopulations. Also, we have identified by bioinformatic and qPCR analysis, different miR expression patterns in colon cancer versus non tumour cells using the previously selected suitable normalizers. Our results emphasize the importance of select suitable normalizers to ensure the robustness and reliability of qPCR data for analyzing miR expression.

The expression of microRNA 574-3p as a predictor of postoperative outcome in patients with esophageal squamous cell carcinoma

BACKGROUND

Despite advances in radical esophagectomies and adjuvant therapy, the postoperative prognosis in esophageal squamous cell carcinoma (ESCC) patients remains poor. The aim of this study was to identify a molecular signature to predict postoperative favorable outcomes in patients with ESCC.

METHODS

As a training data set, total RNA was extracted from formalin-fixed paraffin-embedded samples of surgically removed specimens from 19 ESCC patients who underwent curative esophagectomy. The expression of microRNA (miRNA) was detected using a miRNA oligo chip on which 885 genes were mounted. As a validation data set, we obtained frozen samples of surgically resected tumors from 12 independent ESCC patients and the expression of miR-574-3p was detected by quantitative real-time PCR.

RESULTS

Our microarray analysis in the training set patients identified three miRNAs (miR-574-3p, miR-106b, and miR-1303) and five miRNAs (miR-1203, miR-1909, miR-204, miR-371-3p, miR-886-3p) which were differentially expressed between the patients with (n = 14) and without (n = 5) postoperative tumor relapse (p < 0.01 and p < 0.05, respectively). Higher expression of miR-574-3p, which showed the most significant association with non-relapse (p = 0.001), was associated with favorable overall survival (p = 0.016). Real-time PCR experiments on the validation set patients confirmed that higher expression of miR-574-3p was associated with non-tumor relapse (p = 0.029) and better overall survival (p = 0.004).

CONCLUSIONS

Our results suggest that the aberrant expression of the miRNAs identified in this study plays key roles in the progression of ESCC. miR-574-3p was suggested to have a tumor suppressor effect, and thus, to be a predictor of postoperative outcome in patients with ESCC.

MicroRNA in pancreatic adenocarcinoma: predictive/prognostic biomarkers or therapeutic targets?

Pancreatic ductal adenocarcinoma (PDAC) is a tumor with a poor prognosis, short overall survival and few chemotherapeutic choices. MicroRNAs (miRNAs) are non-coding, single-stranded RNAs of around 22 nucleotides involved in the pathogenic mechanisms of carcinogenesis and metastasis. They have been studied in many tumors in order to identify potential diagnostic, prognostic or therapeutic targets. In the current literature, many studies have analyzed the role of miRNAs in PDAC. In fact, the absence of appropriate biomarkers, the difficultly of early detection of this tumor, and the lack of effective chemotherapy in patients with unresectable disease have focused attention on miRNAs as new, interesting advance in this malignancy.

In this review we analyzed the role of miRNAs in PDAC in order to understand the mechanisms of action and the difference between the onco-miRNA and the tumor suppressor miRNA. We also reviewed all the data related to the use of these molecules as predictive as well as prognostic biomarkers in the course of the disease.

Finally, the possible therapeutic use of miRNAs or anti-miRNAs in PDAC is also discussed.

In conclusion, although there is still no clinical application for these molecules in PDAC, it is our opinion that the preclinical evidence of the role of specific miRNAs in carcinogenesis, the possibility of using miRNAs as diagnostic or prognostic biomarkers, and their potential therapeutic role, warrant future studies in PDAC.

Noncoding RNAs and pancreatic cancer

Noncoding RNAs (ncRNAs) represent a class of RNA molecules that typically do not code for proteins. Emerging data suggest that ncRNAs play an important role in several physiological and pathological conditions such as cancer. The best-characterized ncRNAs are the microRNAs (miRNAs), which are short, approximately 22-nucleotide sequences of RNA of approximately 22-nucleotide in length that regulate gene expression at the posttranscriptional level, through transcript degradation or translational repression. MiRNAs can function as master gene regulators, impacting a variety of cellular pathways important to normal cellular functions as well as cancer development and progression. In addition to miRNAs, long ncRNAs, which are transcripts longer than 200 nucleotides, have recently emerged as novel drivers of tumorigenesis. However, the molecular mechanisms of their regulation and function, and the significance of other ncRNAs such as piwi-interacting RNAs in pancreas carcinogenesis are largely unknown. This review summarizes the growing body of evidence supporting the vital roles of ncRNAs in pancreatic cancer, focusing on their dysregulation through both genetic and epigenetic mechanisms, and highlighting the promise of ncRNAs in diagnostic and therapeutic applications of pancreatic cancer.

miR-615-5p prevents proliferation and migration through negatively regulating serine hydromethyltransferase 2 (SHMT2) in hepatocellular carcinoma

It has been reported that miR-615-5p was upregulated in hepatocellular carcinoma (HCC) preventing both growth and migration. However, the underlying mechanism by which miR-615-5p played a role in HCC remains unknown. Here, in our present study, to investigate the mechanism of miR-615-5p, bioinformatic prediction and luciferase reporter assay were employed to ascertain the downstream target of miR-615-5p finding that the serine hydromethyltransferase 2 (SHMT2) was the direct downstream target. Knockdown or overexpression of miR-615-5p can lead to increasing or decreasing expression of SHMT2 in HCC cells. Besides, knockdown or overexpression of SHMT2 can suppress or promote both proliferation and migration of HCC cells, indicating that miR-615-5p can directly and negatively regulate the SHMT2 in HCC cells. In addition, to understand the clinicopathological significance of SHMT2 expression in HCC, immunohistochemistry was performed. It was found that SHMT2 expression was significantly associated with poor prognosis and TNM stage. Together, our results for the first time showed that miR-615-5p prevents proliferation and migration through negatively regulating SHMT2 in HCC.

MicroRNA Signaling Pathway Network in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is considered to be the most lethal and aggressive malignancy with high mortality and poor prognosis. Their responses to current multimodal therapeutic regimens are limited. It is urgently needed to identify the molecular mechanism underlying pancreatic oncogenesis. Twelve core signaling cascades have been established critical in PDAC tumorigenesis by governing a wide variety of cellular processes. MicroRNAs (miRNAs) are aberrantly expressed in different types of tumors and play pivotal roles as post-transcriptional regulators of gene expression. Here, we will describe how miRNAs regulate different signaling pathways that contribute to pancreatic oncogenesis and progression.