miR-7 Increases Cisplatin Sensitivity of Gastric Cancer Cells Through Suppressing mTOR

'Investigation of miRNAs That Affect the PI3K/AKT/mTOR Signaling Pathway in Endometrial Cancer'

Endometrial cancer is a prevalent type of cancer among women worldwide. The irregularity of the PI3K/AKT/mTOR signaling pathway plays a role in the pathogenesis of many cancer types. MicroRNAs are small noncoding RNAs that play crucial roles in the pathogenesis of different cancer types. MicroRNAs target many key components of the PI3K/AKT/mTOR pathway in human tumors. In this study the PI3K/AKT/mTOR pathway was affected in endometrial cancer, and the expression levels of miR-7, miR-17, miR-145, miR-155, miR-206, miR-221, miR-222 were determined. In addition, in silico analyses were examine the molecular interactions between miRNAs and target genes. Identifying dysregulated miRNA expression in endometrial cancer is important for developing miRNA-based therapeutic strategies. In our study, Grade 1 (n = 16), Grade 2 (n = 16), Grade 3 (n = 16), tissues diagnosed with endometrioid adeno carcinoma, control 1 (n = 16) secretory phase and control 2 (n = 16) proliferative phase healthy endometrial tissues without endometrial cancer were included. miRNA expression analysis was performed using the real-time PCR. In our study, the expression of miR-7-5p, miR-145-5p, and miR-206 decreased, whereas the expression of miR-17-5p, miR-221-3p, and miR-222-3p increased in endometrial cancer (p < 0,05). Statistically significant results were not obtained to for the expression levels of miR-21-5p and miR-155-5p. miR-7-5p targets PIK3CD, PIK3R3, PIK3CB and AKT3, miR-17-5p targets PIK3R1 and AKT3, miR-21-5p target PIK3R1, miR-145-5p target AKT3, miR-155-5p targets PIK3CA and PIK3R1, miR-206 target PIK3C2A, miR-221-3p and miR-222-3p target PIK3R1 as identified via in silico analysis. These results can shed light on the development of molecular-targeted therapy strategies. Treatment strategies can be developed by designing ASOs, LNAs, miRNA antagomirs, or miRNA sponges for upregulated miR-17-5p, miR-221-3p, and miR-222-3p, and miRNA mimics for downregulated miR-7-5p, miR-145-5p, and miR-206.

Molecular mechanisms of mTOR-mediated cisplatin response in tumor cells

Cisplatin (CDDP) is one of the main chemotherapeutic drugs that is widely used in many cancers. However, CDDP resistance is a frequent therapeutic challenge that reduces prognosis in cancer patients. Since, CDDP has noticeable side effects in normal tissues and organs, it is necessary to assess the molecular mechanisms associated with CDDP resistance to improve the therapeutic methods in cancer patients. Drug efflux, detoxifying systems, DNA repair mechanisms, and drug-induced apoptosis are involved in multidrug resistance in CDDP-resistant tumor cells. Mammalian target of rapamycin (mTOR), as a serine/threonine kinase has a pivotal role in various cellular mechanisms such as autophagy, metabolism, drug efflux, and cell proliferation. Although, mTOR is mainly activated by PI3K/AKT pathway, it can also be regulated by many other signaling pathways. PI3K/Akt/mTOR axis functions as a key modulator of drug resistance and unfavorable prognosis in different cancers. Regarding, the pivotal role of mTOR in CDDP response, in the present review we discussed the molecular mechanisms that regulate mTOR mediated CDDP response in tumor cells.

Bioengineered miR-7-5p modulates non-small cell lung cancer cell metabolism to improve therapy

Reintroduction of tumor-suppressive microRNA-7-5p (miR-7) that is depleted in non-small cell lung cancer (NSCLC) represents a new therapeutic approach, whereas previous studies mainly used miR-7 mimics chemoengineered in vitro. Here we aim to establish the pharmacological actions and therapeutic potential of novel bioengineered RNA bearing a payload miR-7 (BioRNA/miR-7) molecule produced in vivo. First, through confocal imaging and immunoblot studies, we revealed that BioRNA/miR-7 altered NSCLC cell mitochondrial morphology accompanied by the downregulation of known target genes, epidermal growth factor receptor (EGFR), mitochondrial solute carrier family 25A37 (SLC25A37), and import inner membrane translocase subunit (TIM50). Second, through luciferase reporter and immunoblot studies, we validated mitochondrial acylglycerol kinase (AGK) as a new direct target for miR-7. Third, through real-time live-cell analyses, we revealed BioRNA/miR-7 to modulate mitochondrial respiration and glycolytic capacity. Fourth, live-cell and endpoint viability studies demonstrated that the combination of BioRNA/miR-7 with pemetrexed (PEM) elicited a strong synergistic effect to inhibit NSCLC cell growth, associated with an increased intracellular PEM accumulation, as quantified by a liquid chromatography tandem mass spectrometry method. Finally, through in vivo therapy study using NSCLC patient-derived xenograft mouse model, we demonstrated the efficacy and tolerability of BioRNA/miR-7 monotherapy and combination therapy with PEM to control tumor progression. Our collective works establish a role for miR-7 in NSCLC metabolism and PEM disposition and support our novel, in vivo produced BioRNA/miR-7-5p for molecular pharmacological research. Our findings further illustrate the potential of BioRNA/miR-7 plus PEM combination as a potential treatment to combat NSCLC tumor progression. SIGNIFICANCE STATEMENT: MiR-7 is a tumor-suppressive microRNA depleted in non-small cell lung cancer (NSCLC), and in vitro chemoengineered miR-7 mimics were shown to inhibit tumor growth in NSCLC cell-derived xenograft mice. Here, a novel in vivo bioengineered miR-7 molecule, namely BioRNA/miR-7, was used to effectively control target gene expression and NSCLC cell metabolism. Furthermore, BioRNA/miR-7 was demonstrated to remarkably improve pemetrexed antitumor activity in NSCLC patient-derived tumor mice, supporting the role of miR-7 in NSCLC metabolism and potential for BioRNA/miR-7 to improve NSCLC therapy.

Non-coding RNAs as potential therapeutic targets for receptor tyrosine kinase signaling in solid tumors: current status and future directions

This review article presents an in-depth analysis of the current state of research on receptor tyrosine kinase regulatory non-coding RNAs (RTK-RNAs) in solid tumors. RTK-RNAs belong to a class of non-coding RNAs (nc-RNAs) responsible for regulating the expression and activity of receptor tyrosine kinases (RTKs), which play a critical role in cancer development and progression. The article explores the molecular mechanisms through which RTK-RNAs modulate RTK signaling pathways and highlights recent advancements in the field. This include the identification of potential new RTK-RNAs and development of therapeutic strategies targeting RTK-RNAs. While the review discusses promising results from a variety of studies, encompassing in vitro, in vivo, and clinical investigations, it is important to acknowledge the challenges and limitations associated with targeting RTK-RNAs for therapeutic applications. Further studies involving various cancer cell lines, animal models, and ultimately, patients are necessary to validate the efficacy of targeting RTK-RNAs. The specificity of ncRNAs in targeting cellular pathways grants them tremendous potential, but careful consideration is required to minimize off-target effects, the article additionally discusses the potential clinical applications of RTK-RNAs as biomarkers for cancer diagnosis, prognosis, and treatment. In essence, by providing a comprehensive overview of the current understanding of RTK-RNAs in solid tumors, this review emphasizes their potential as therapeutic targets for cancer while acknowledging the associated challenges and limitations.

lncRNA TINCR promotes the development of cervical cancer via the miRNA‑7/mTOR axis in vitro

The present study aimed to examine the effects of the long non-coding (lnc)RNA expressed by tissue differentiation-inducing non-protein coding RNA (TINCR) on cervical cancer development. For this purpose, adjacent normal and cancer tissues were obtained from patients with cervical cancer and the lncRNA TINCR level was examined using reverse transcription-quantitative PCR (RT-qPCR) and in situ hybridization. The association between lncRNA TINCR and the clinicopathological characteristics and prognosis of patients with cervical cancer was also analyzed. Furthermore, the expression levels of lncRNA TINCR, miRNA-7, mTOR, hypoxia-inducible factor 1 subunit α and VEGF were measured using RT-qPCR and western blot analysis. Cell proliferation, apoptosis, and invasion and migration were examined using MTT assay, 5-ethynyl-2'-deoxyuridine staining, flow cytometry, TUNEL assay, and Transwell and wound healing assays. The association between lncRNA TINCR, miRNA-7 and mTOR was also examined using a luciferase assay. The results revealed that the lncRNA TINCR level was significantly increased in cervical cancer tissues and was associated with the overall survival of patients (low vs. high expression group; P=0.0391). LncRNA TINCR was also associated with the clinicopathological characteristics of patients with cervical cancer. Following the knockdown of lncRNA TINCR using small interfering (si)RNA, cell proliferation was significantly decreased and cell apoptosis was significantly increased (P<0.001 for both); cell invasion and migration were also significantly decreased (P<0.001 for both) following transfection with mimics miRNA-7. Transfection with miRNA-7 antisense oligonucleotide decreased the antitumor effects of si-TINCR in Siha and HeLa cell lines. As shown using the dual-luciferase assay, lncRNA TINCR could target miRNA-7 and miRNA-7 could directly regulate mTOR in HeLa and SiHa cell lines. In conclusion, the present study demonstrated that lncRNA TINCR could promote cervical cancer development via regulation of the miRNA-7/mTOR axis in vitro.

Effects of icariin and curcumol on autophagy, ferroptosis, and lipid metabolism based on miR-7/m-TOR/SREBP1 pathway on prostate cancer

This study aimed to investigate the effects and underlying molecular mechanisms of icariin (ICA) and curcumol on autophagy, ferroptosis, and lipid metabolism in prostate cancer (PCa), in vitro and in vivo. Normal prostate epithelial cells RWPE-1 and PCa cell lines DU145 and PC-3 were treated with ICA and curcumol. Ferrostatin-1 (Fer-1) or 3-MA was added to treat DU145 and PC-3 cells. In addition, we knocked down miR-7. The mechanism of ICA and curcumol in PCa cells after the knockdown of miR-7 was verified by in vitro nude mice tumorigenesis experiments. ICA and curcumol had no significant effect on the viability of RWPE-1 cells, but there was a significant difference between DU145 and PC-3 cells. After treatment with ICA and curcumol, the proliferation of PCa cells was inhibited, apoptosis, reactive oxygen species (ROS) levels, and miR-7 expression were increased. The combined treatment of ICA and curcumol had a more significant effect. ICA and curcumol treatment induced autophagy and ferroptosis in PCa cells, and si-miR-7 reversed the effects of ICA and curcumol on autophagy and ferroptosis. MiR-7 targeted mTOR and regulated the expression of the mTOR/SREBP1 pathway in PCa cells. ICA and curcumol may affect the lipid metabolism of PCa cells by affecting SREBP1. In addition, the effects and mechanisms of ICA and curcumol on autophagy, ferroptosis, and lipid metabolism in PCa cells were verified in vivo. ICA and curcumol synergistically regulated the miR-7/mTOR/SREBP1 pathway to induce autophagy and ferroptosis in PCa cells and affected lipid metabolism.

MicroRNA-92a-3p Enhances Cisplatin Resistance by Regulating Krüppel-Like Factor 4-Mediated Cell Apoptosis and Epithelial-to-Mesenchymal Transition in Cervical Cancer

Recent studies have confirmed the existence and key roles of microRNA (miRNAs) in cancer drug resistance, including cervical cancer (CC). The present study aims to establish a novel role for miR-92a-3p and its associated gene networks in cisplatin (DDP) resistance of CC. First, the disparities in miRNA expression between CC tissues and adjacent normal tissues were screened based on GSE19611 microarray data that retrieved from Gene Expression Omnibus (GEO), and we identified several miRs that were significantly downregulated or upregulated in CC tissues including miR-92a-3p. Moreover, miR-92a-3p was significantly up-regulated in DDP-resistant cells and was the most differently expressed miRNA. Functionally, knockdown of miR-92a-3p increased the sensitivity of DDP-resistant cells to DDP via inhibiting cell proliferation, migration and invasion, and promoting apoptosis. Conversely, overexpression of miR-92a-3p significantly induced DDP resistance in CC parental cells including HeLa and SiHa cells. Moreover, Krüppel-like factor 4 (KLF4) was identified as a direct target of miR-92a-3p, and an obvious inverse correlation was observed between the expression of miR-92a-3p and KLF4 in 40 pairs of cancer tissues. Furthermore, KLF4 knockdown reversed the promoting effect of miR-92a-3p inhibition on DDP sensitivity in DDP-resistant CC cells. Besides, high expression of miR-92a-3p was associated with DDP resistance, as well as a short overall survival in clinic. Taken together, these findings provide important evidence that miR-92a-3p targets KLF4 and is significant in DDP resistance in CC, indicating that miR-92a-3p may be an attractive target to increase DDP sensitivity in clinical CC treatment.

Non-Coding RNAs in Gastric Cancer: From Malignant Hallmarks to Clinical Applications

Gastric cancer (GC) is one of the most lethal malignancies worldwide. However, the molecular mechanisms underlying gastric carcinogenesis remain largely unknown. Over the past decades, advances in RNA-sequencing techniques have greatly facilitated the identification of various non-coding RNAs (ncRNAs) in cancer cells, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Accumulating evidence has revealed that ncRNAs are essential regulators in GC occurrence and development. However, ncRNAs represent an emerging field of cancer research, and their complex functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets in GC, further studies should focus on elucidating the intricate relationships between ncRNAs and GC, which can be translated into clinical practice. In this review, we summarize recent research progress on how ncRNAs modulate the malignant hallmarks of GC, especially in tumor immune escape, drug resistance, and stemness. We also discuss the promising applications of ncRNAs as diagnostic biomarkers and therapeutic targets in GC, aiming to validate their practical value for clinical treatment.

Circular RNA WHSC1 exerts oncogenic properties by regulating miR-7/TAB2 in lung cancer

Circular RNA is a newly discovered member of non‐coding RNA (ncRNA) and regulates the target gene by acting as a micro‐RNA sponge. It plays vital roles in various diseases. However, the functions of circular RNA in non‐small cell lung cancer (NSCLC) remain still unclear. Our data showed that circ‐WHSC1 was highly expressed in NSCLC cells and tissues. Both in vitro and in vivo experiments showed that circ‐WHSC1 promoted NSCLC proliferation. circ‐WHSC1 also promoted the migration and invasion of lung cancer cells. Through bioinformatic analysis and functional experiments, we showed that circ‐WHSC1 could act as a sponge for micro‐RNA‐7 (miR‐7) and regulate the expression of TAB2 (TGF‐beta activated kinase one binding protein two). Inhibition of the circ‐WHSC1/miR‐7/TAB2 pathway could effectively attenuate lung cancer progression. In summary, this study confirmed the existence and oncogenic function of circ‐WHSC1 in NSCLC. The research suggests that the circ‐WHSC1/miR‐7/TAB2 axis might be a potential target for NSCLC therapy.

MicroRNAs are involved in the development and progression of gastric cancer

MicroRNAs (miRNAs) are recognized as an essential component of the RNA family, exerting multiple and intricate biological functions, particularly in the process of tumorigenesis, proliferation, and metastatic progression. MiRNAs are altered in gastric cancer (GC), showing activity as both tumor suppressors and oncogenes, although their true roles have not been fully understood. This review will focus upon the recent advances of miRNA studies related to the regulatory mechanisms of gastric tumor cell proliferation, apoptosis, and cell cycle. We hope to provide an in-depth insight into the mechanistic role of miRNAs in GC development and progression. In particular, we summarize the latest studies relevant to miRNAs' impact upon the epithelial-mesenchymal transition, tumor microenvironment, and chemoresistance in GC cells. We expect to elucidate the molecular mechanisms involving miRNAs for better understanding the etiology of GC, and facilitating the development of new treatment regimens for the treatment of GC.

MicroRNAs as the critical regulators of cisplatin resistance in gastric tumor cells

Combined chemotherapeutic treatment is the method of choice for advanced and metastatic gastric tumors. However, resistance to chemotherapeutic agents is one of the main challenges for the efficient gastric cancer (GC) treatment. Cisplatin (CDDP) is used as an important regimen of chemotherapy for GC which induces cytotoxicity by interfering with DNA replication in cancer cells and inducing their apoptosis. Majority of patients experience cisplatin-resistance which is correlated with tumor metastasis and relapse. Moreover, prolonged and high-dose cisplatin administrations cause serious side effects such as nephrotoxicity, ototoxicity, and anemia. Since, there is a high rate of recurrence after CDDP treatment in GC patients; it is required to clarify the molecular mechanisms associated with CDDP resistance to introduce novel therapeutic methods. There are various cell and molecular processes associated with multidrug resistance (MDR) including drug efflux, detoxification, DNA repair ability, apoptosis alteration, signaling pathways, and epithelial-mesenchymal transition (EMT). MicroRNAs are a class of endogenous non-coding RNAs involved in chemo resistance of GC cells through regulation of all of the MDR mechanisms. In present review we have summarized all of the miRNAs associated with cisplatin resistance based on their target genes and molecular mechanisms in gastric tumor cells. This review paves the way of introducing a miRNA-based panel of prognostic markers to improve the efficacy of chemotherapy and clinical outcomes in GC patients. It was observed that miRNAs are mainly involved in cisplatin response of gastric tumor cells via regulation of signaling pathways, autophagy, and apoptosis.

Prognosis prediction model for a special entity of gastric cancer, linitis plastica

Background

Gastric linitis plastica (GLP) is characteristic by its poor prognosis and highly aggressive characteristics compared with other types of gastric cancer (GC). However, the guidelines have not yet been distinguished between GLP and non-GLP.

Methods

A total of 342 eligible patients with GLP identified in the Surveillance, Epidemiology, and End Results (SEER) dataset were randomly divided into training set (n=298) and validation set (n=153). A nomogram would be developed with the constructed predicting model based on the training cohort's data, and the validation cohort would be used to validate the model. Principal component analysis (PCA) was used to evaluate the differences between groups. Cox regression and LASSO (least absolute shrinkage and selection operator) were used to construct the models. Calibration curve, time-dependent receiver operating characteristic (ROC) curve, concordance index (C-index) and decision curve analysis (DCA) were used to evaluate the predicting performance. Restricted mean survival time (RMST) was used to analyze the curative effect of adjuvant therapy.

Results

For patients in training cohort, univariable and multivariable Cox analyses showed that age, examined lymph nodes (LN.E), positive lymph nodes (LN.P), lesion size, combined resection, and radiotherapy are independent prognostic factors for overall survival (OS), while chemotherapy can not meet the proportional hazards (PHs) assumption; age, race, lesion size, LN.E, LN.P, combined resection and marital status are independent prognostic factors for cancer-specific survival (CSS). The C-index of the nomogram was 0.678 [95% confidence interval (CI), 0.660-0.696] and 0.673 (95% CI, 0.630-0.716) in the training and validation cohort, respectively. Meanwhile, the C-index of the CSS nomogram was 0.671 (95% CI, 0.653-0.699) and 0.650 (95% CI, 0.601-0.691) in the training and validation cohort for CSS, respectively. Furthermore, the nomogram was well calibrated with satisfactory consistency. RMST analysis further determined that chemotherapy and radiotherapy might be beneficial for improving 1- and 3-year OS and CSS, but not the 5-year CSS.

Conclusions

We developed nomograms to help predict individualized prognosis for GLP patients. The new model might help guide treatment strategies for patients with GLP.

The Role of miRNA-7 in the Biology of Cancer and Modulation of Drug Resistance

MicroRNAs (miRNAs, miRs) are small non-coding RNA (ncRNA) molecules capable of regulating post-transcriptional gene expression. Imbalances in the miRNA network have been associated with the development of many pathological conditions and diseases, including cancer. Recently, miRNAs have also been linked to the phenomenon of multidrug resistance (MDR). MiR-7 is one of the extensively studied miRNAs and its role in cancer progression and MDR modulation has been highlighted. MiR-7 is engaged in multiple cellular pathways and acts as a tumor suppressor in the majority of human neoplasia. Its depletion limits the effectiveness of anti-cancer therapies, while its restoration sensitizes cells to the administered drugs. Therefore, miR-7 might be considered as a potential adjuvant agent, which can increase the efficiency of standard chemotherapeutics.

MicroRNA in Gastric Cancer Development: Mechanisms and Biomarkers

Gastric cancer (GC) is one of the most common and difficult diseases to treat. The study of signaling pathway regulation by microRNA provides information on the mechanisms of GC development and is the basis for biomarker creation. In this study, a circuit of microRNA interactions with signaling pathways was constructed. The microRNAs, associated with metastasis and chemoresistance, are described. In most cases, microRNAs in GC regulate the Wnt/β-catenin, PI3K/AKT/mTOR, RAS/RAF/ERK/MAPK, NF-kB, TGF-β, and JAK/STAT pathways. Part of the microRNA acts on several target genes that function in different pathways. This often leads to an intensification of the induced processes. MicroRNAs have also been described that have the opposite effect on different pathways, causing different functional consequences. By acting on several target genes, or genes associated with several pathways, microRNAs can function in a signaling network. MicroRNAs associated with metastasis most often interact with the Wnt/β-catenin pathway. MicroRNAs affecting chemoresistance, in most cases, affect the regulators of apoptosis and are associated with the PI3K/AKT/mTOR pathway. The characteristics of microRNAs proposed as candidates for GC biomarkers were analyzed. The currently developed diagnostic and prognostic panels of microRNAs are also considered.

Elevated microRNA-7 inhibits proliferation and tumor angiogenesis and promotes apoptosis of gastric cancer cells via repression of Raf-1

OBJECTIVE

Since the essential involvement of microRNAs (miRNAs) in the development and progression of GC, the study was for the exploration of the value of microRNA-7 (miR-7) in the evaluation of neoadjuvant chemotherapy for gastric cancer (GC) and its effects on apoptosis, proliferation and angiogenesis of GC.

METHODS

miR-7 expression in serum of GC patients before and after neoadjuvant chemotherapy were detected to explore its role in neoadjuvant chemotherapy of GC. The GC cells were transfected with miR-7 mimics/inhibitors, or siRNA-Raf-1 to figure out their roles in proliferation, migration, invasion, cycle distribution and apoptosis. Tumor xenograft was conducted to test tumor growth. Microvessel density (MVD) in tumors was tested by immunohistochemical staining.

RESULTS

miR-7 expression in serum of GC patients was lower than that of healthy controls while it was elevated after neoadjuvant chemotherapy. Moreover, higher miR-7 expression was exhibited in chemotherapy-effective patients rather than chemotherapy-ineffective patients (P < 0.01). miR-7 expression in serum was connected with tumor size, degree of differentiation, TNM stage and lymphatic metastasis.miR-7 was decreased and Raf-1 was elevated in GC cells (both P < 0.05). Elevated miR-7 or declined Raf-1 inhibited GC cell migration, proliferation and invasion, cell cycle entry, xenografted tumor growth and MVD and stimulated apoptosis (all P < 0.05). Down-regulated Raf-1 reversed the impacts of miR-7 knockdown on GC cells (all P < 0.05).

CONCLUSION

Our study highlights that elevated miR-27a indicates the good efficacy of neoadjuvant chemotherapy in GC and miR-7 targets Raf-1 to suppress tumor development and angiogenesis of GC cells.

Role of microRNA-7 in liver diseases: a comprehensive review of the mechanisms and therapeutic applications

MicroRNA-7 (miR-7) is a small non-coding RNA, which plays critical roles in regulating gene expression of multiple key cellular processes. MiR-7 exhibits a tissue-specific pattern of expression, with abundant levels found in the brain, spleen, and pancreas. Although it is expressed at lower levels in other tissues, including the liver, miR-7 is involved in both the development of organs and biological functions of cells. In this review, we focus on the mechanisms by which miR-7 controls cell growth, proliferation, invasion, metastasis, metabolism, and inflammation. We also summarize the specific roles of miR-7 in liver diseases. MiR-7 is considered as a tumor suppressor miRNA in hepatocellular carcinoma and is involved in the pathogenesis of hepatic steatosis and hepatitis. Future studies to further define miR-7 functions and its mechanism in association with other types of liver diseases should be explored. An improved understanding from these studies will provide us a useful perspective leading to mechanism-based intervention by targeting miR-7 for the treatment of liver diseases.

lncRNA TINCR facilities bladder cancer progression via regulating miR‑7 and mTOR

Long non-coding RNAs (lncRNAs) have been implicated in various human malignancies, but the molecular mechanism of lncRNA TINCR ubiquitin domain containing (TINCR) in bladder cancer remains unclear. The present study found that the expression of TINCR was significantly increased in bladder cancer tissues and cell lines, when compared with that in adjacent normal tissues and normal urinary tract epithelial cell line SV-HUC-1, respectively. Moreover, the high expression of TINCR was associated with tumor metastasis and advanced tumor, node, metastasis stage, as well as reduced overall survival rates of patients with bladder cancer. Further investigation revealed that microRNA (miR)-7 was negatively mediated by TINCR in bladder cancer cells. Silencing of TINCR expression significantly increased miR-7 expression and reduced bladder cancer cell proliferation, migration and invasion, while knockdown of miR-7 expression reversed the inhibitory effects of TINCR downregulation on bladder cancer cells. mTOR was then identified as a target gene of miR-7 in bladder cancer, and it was demonstrated that overexpression of mTOR reversed the inhibitory effects of miR-7 on bladder cancer cells. In conclusion, this study suggests that TINCR/miR-7/mTOR signaling may be a potential therapeutic target for bladder cancer.

MicroRNA-7, synergizes with RORα, negatively controls the pathology of brain tissue inflammation

BACKGROUND

Accumulating evidence has documented that microRNA-7 (miR-7) plays an important role in the pathology of various diseases. However, the potential role of miR-7 in brain tissue inflammation (BTI) remains unclear.

METHODS

We detected the expression of miR-7 in LPS-induced murine BTI model and observed the possible effects of miR-7 deficiency on the pathology of BTI. To elucidate the mechanism, the target gene of miR-7 was screened out by Gene chip assay and its potential roles in BTI were evaluated by Western blot, immunofluorescence, and RNAi assay, respectively.

RESULTS

MiR-7 was upregulated in brain tissue in BTI mice and its deficiency could significantly aggravate the pathology of brain tissue. Moreover, RORα, a new target molecule of miR-7, was upregulated in brain tissue from miR-7 deficiency BTI mice. Of note, downregulation of RORα could remarkably exacerbate the pathology of brain tissue and elevate the transduction of NF-κB and ERK1/2 signaling pathways in brain tissue from miR-7 deficiency BTI mice. Furthermore, RORα and miR-7 were dominantly co-expressed in neurons of BTI mice. Finally, RORα synergized with miR-7 to control the inflammatory reaction of neuronal cells in response to LPS stimulation.

CONCLUSIONS

MiR-7 expression is upregulated in BTI model. Moreover, miR-7 synergizes with its target gene RORα to control the inflammation reaction of neurons, thereby orchestrating the pathology of BTI.

Research Progress in microRNA-Based Therapy for Gastric Cancer

Gastric cancer (GC) is one of the leading causes of tumor-related mortality. In addition to surgery and endoscopic resection, systemic therapy remains the main treatment option for GC, especially for advanced-stage disease and for cases not suitable for surgical therapy. Hence, improving the efficacy of systemic therapy is still an urgent problem to overcome. In the past decade, the essential roles of microRNAs (miRNAs) in tumor treatment have been increasingly recognized. In particular, miRNAs were recently shown to reverse the resistance to chemotherapy drugs such as 5-fluorouracil, cisplatin, and doxorubicin. Synthesized nanoparticles loaded with mimics or inhibitors of miRNAs can directly target tumor cells to suppress their growth. Moreover, exosomes may serve as promising safe carriers for mimics or inhibitors of miRNAs to treat GC. Some miRNAs have also been shown to play roles in the mechanism of action of other anti-tumor drugs. Therefore, in this review, we highlight the research progress on microRNA-based therapy in GC and discuss the challenges and prospects associated with this strategy. We believe that microRNA-based therapy has the potential to offer a clinical benefit to GC patients, and this review would contribute to and motivate further research to promote this field toward this ultimate goal.

The better effects of microbubble ultrasound transfection of miR-940 on cell proliferation inhibition and apoptosis promotion in human cervical cancer cells

Purpose

Cervical cancer is the second leading cause of women’s cancer-related death. MiR-940 has been reported as a critical factor in various cancers. Based on the high transfection efficiency and low side effect, the clinical application of microbubble ultrasound contrast agent in gene treatment has attracted a widespread attention. In this study, we determined the mechanism of miR-940 inhibiting cell proliferation and cycle procession, and promoting cell apoptosis in cervical cancer Hela cells. In addition, we compared the effects of different transfection methods, including liposome, microbubble, ultrasound, and microbubble coupled with ultrasound.

Patients and methods

MTT assay, PI staining, and Annexin-Ⅴ/PI staining assays were, respectively, performed to evaluate cell proliferation status, cell cycle progression, and apoptosis status. RT-PCR and Western blot were conducted to measure the levels of cell cycle- and apoptosis-related factors, and the phosphorylation levels of PI3K and Akt.

Results

Results showed that the overexpression of miR-940 inhibited cell proliferation, blocked cell cycle, and promoted apoptosis by regulating cell cycle-related factors (such as inhibited Cyclin D1 and CDK4) and apoptosis-related factors (such as promoted Puma and Bax, inhibited Bcl-2 and Cleaved caspase9), and inhibiting the phosphorylation and activation of PI3K/AKT pathway. Among all of them, miR-940 transfected with microbubble and ultrasound showed the greatest changes.

Conclusion

It provides evidence that miR-940 could be a wonderful biomarker and treatment agent for cervical cancer, and microbubble ultrasound would have more wide application in the clinical treatment of cancers.

Emerging roles of microRNAs in regulating the mTOR signaling pathway during tumorigenesis

The mammalian target of rapamycin (mTOR) is a large Ser/Thr protein kinase that belongs to the phosphoinositide 3-kinase (PI3K) family and mediates various physiological and pathological processes, especially cell proliferation, protein synthesis, autophagy, and cancer development. The mTOR expression is transient and tightly regulated in normal cells, but it is overactivated in cancer cells. Recently, several studies have indicated that microRNAs (miRNAs) play a critical role in the regulation of mTOR and mTOR-associated processes, some acting as inhibitors and the others as activators. Although it is still in infancy, the strategy of combining both miRNAs and mTOR inhibitors might provide an approach to selectively sensitizing tumor cells to chemotherapy-induced DNA damage and subsequently attenuating the tumor cell growth and apoptosis.

Hypoxia-induced regulation of mTOR signaling by miR-7 targeting REDD1

Oxygen is an important factor mediating cell growth and survival under physiological and pathological conditions. Therefore, cells have well-regulated response mechanisms in the face of changes in oxygen levels in their environment. A subset of microRNAs (miRNAs) termed the hypoxamir has been suggested to be a critical mediator of the cellular response to hypoxia. Regulated in development and DNA damage response 1 (REDD1) is a negative regulator of mammalian target of rapamycin (mTOR) signaling in the response to cellular stress, and is elevated in many cell types under hypoxia, with consequent inhibition of mTOR signaling. However, the underlying posttranscriptional regulatory mechanism by miRNAs that contribute to this hypoxia-induced reduction in REDD1 expression remain unknown. Therefore, the aim of the current study was to identify the miRNAs participating in the hypoxic cellular response by scanning the 3'-untranslated region (3'-UTR) of REDD1 for potential miRNA-binding sites using a computer algorithm, TargetScan. miR-7 emerged as a novel hypoxamir that regulates REDD1 expression and is involved in mTOR signaling. miR-7 could repress REDD1 expression posttranscriptionally by directly binding with the 3'-UTR. Upon hypoxia, miR-7 expression was downregulated in HeLa cells to consequently derepress REDD1, resulting in inhibition of mTOR signaling. Moreover, overexpression of miR-7 was sufficient to reverse the hypoxia-induced inhibition of mTOR signaling. Therefore, our findings suggest miR-7 as a key regulator of hypoxia-mediated mTOR signaling through modulation of REDD1 expression. These findings contribute new insight into the miRNA-mediated molecular mechanism of the hypoxic response through mTOR signaling, highlighting potential targets for tumor suppression.

mTOR signaling-related MicroRNAs and Cancer involvement

MicroRNAs (miRNAs) are a class of single-stranded RNAs, 18-23 nucleotides in length that regulate gene expression at the post-transcriptional level. Dysregulation of miRNAs has been closely associated with the development of cancer. In the process of tumorigenesis, mammalian target of rapamycin (mTOR) plays important roles, and the mTOR signaling pathway is aberrant in various types of human cancers, including non-small cell lung cancer (NSCLC), breast cancer, prostate cancer, as well as others. However, the relationship between miRNAs and the mTOR signaling pathway is indistinct. Herein, we not only summarize the progress of miRNAs and the mTOR signaling pathway in cancers, but also highlight their role in the diagnosis and treatment in the clinic.