MicroRNA-193b acts as a tumor suppressor gene in human esophageal squamous cell carcinoma via target regulation of KRAS

MicroRNAs: A novel signature in the metastasis of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a malignant epithelial tumor, characterized by squamous cell differentiation, it is the sixth leading cause of cancer-related deaths globally. The increased mortality rate of ESCC patients is predominantly due to the advanced stage of the disease when discovered, coupled with higher risk of metastasis, which is an exceedingly malignant characteristic of cancer, frequently leading to a high mortality rate. Unfortunately, there is currently no specific and effective marker to predict and treat metastasis in ESCC. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules, approximately 22 nucleotides in length. miRNAs are vital in modulating gene expression and serve pivotal regulatory roles in the occurrence, progression, and prognosis of cancer. Here, we have examined the literature to highlight the intimate correlations between miRNAs and ESCC metastasis, and show that ESCC metastasis is predominantly regulated or regulated by genetic and epigenetic factors. This review proposes a potential role for miRNAs as diagnostic and therapeutic biomarkers for metastasis in ESCC metastasis, with the ultimate aim of reducing the mortality rate among patients with ESCC.

Emerging role of non-coding RNAs in the regulation of KRAS

The Kirsten ras oncogene KRAS is a member of the small GTPase superfamily participating in the RAS/MAPK pathway. A single amino acid substitution in KRAS gene has been shown to activate the encoded protein resulting in cell transformation. This oncogene is involved in the malignant transformation in several tissues. Notably, numerous non-coding RNAs have been found to interact with KRAS protein. Such interaction results in a wide array of human disorders, particularly cancers. Orilnc1, KIMAT1, SLCO4A1-AS1, LINC01420, KRAS1P, YWHAE, PART1, MALAT1, PCAT-1, lncRNA-NUTF2P3-001 and TP53TG1 are long non-coding RNAs (lncRNAs) whose interactions with KRAS have been verified in the context of cancer. miR-143, miR-96, miR-134 and miR-126 have also been shown to interact with KRAS in different tissues. Finally, circITGA7, circ_GLG1, circFNTA and circ-MEMO1 are examples of circular RNAs (circRNAs) that interact with KRAS. In this review, we describe the interaction between KRAS and lncRNAs, miRNAs and circRNAs, particularly in the context of cancer.

MIMRDA: A Method Incorporating the miRNA and mRNA Expression Profiles for Predicting miRNA-Disease Associations to Identify Key miRNAs (microRNAs)

Identifying cancer-related miRNAs (or microRNAs) that precisely target mRNAs is important for diagnosis and treatment of cancer. Creating novel methods to identify candidate miRNAs becomes an imminent Frontier of researches in the field. One major obstacle lies in the integration of the state-of-the-art databases. Here, we introduce a novel method, MIMRDA, which incorporates the miRNA and mRNA expression profiles for predicting miRNA-disease associations to identify key miRNAs. As a proof-of-principle study, we use the MIMRDA method to analyze TCGA datasets of 20 types (BLCA, BRCA, CESE, CHOL, COAD, ESCA, HNSC, KICH, KIRC, KIRP, LIHC, LUAD, LUSC, PAAD, PRAD, READ, SKCM, STAD, THCA and UCEC) of cancer, which identified hundreds of top-ranked miRNAs. Some (as Category 1) of them are endorsed by public databases including TCGA, miRTarBase, miR2Disease, HMDD, MISIM, ncDR and mTD; others (as Category 2) are supported by literature evidences. miR-21 (representing Category 1) and miR-1258 (representing Category 2) display the excellent characteristics of biomarkers in multi-dimensional assessments focusing on the function similarity analysis, overall survival analysis, and anti-cancer drugs’ sensitivity or resistance analysis. We compare the performance of the MIMRDA method over the Limma and SPIA packages, and estimate the accuracy of the MIMRDA method in classifying top-ranked miRNAs via the Random Forest simulation test. Our results indicate the superiority and effectiveness of the MIMRDA method, and recommend some top-ranked key miRNAs be potential biomarkers that warrant experimental validations.

Pronounced Enhancement in Radiosensitization of Esophagus Cancer Cultivated in Docosahexaenoic Acid via the PPAR -γ Activation

Docosahexaenoic acid (DHA) has been reported to suppress the tumor growth and improve prognosis and has been used to cooperate with many other chemotherapy medicines. Up to now, surveys focused on the Interaction between DHA and radiation are relatively modest. Our study sought to evaluate the radiosensitivity changes caused by DHA on esophageal cancer cells. We selected TE-1 and TE-10 esophagus cancer cells as models and performed routine cell proliferation assay and cloning assay to detect the impact of DHA combined with X-ray. We used cell cycle assay, lipid peroxidation assay, comet assay, and apoptosis assay to unearth the potential causes. We also launched a mouse transplanted tumor experiment to verify the synergetic effect of DHA and irradiation. Finally, a western blot assay was used to find a novel mechanism. As a result, DHA improved TE-1 and TE-10 radiosensitivity in vivo and in vitro. What's more, PPAR-γ expression increased due to the DHA supplement. Inhibiting PPAR-γ could attenuate benefits brought out by DHA somehow. Due to its explicit usage and convenience, DHA would serve as an adjuvant therapy before radiotherapy if the clinical trials indicated positive.

miRNA-193b-5p Suppresses Pancreatic Cancer Cell Proliferation, Invasion, Epithelial Mesenchymal Transition, and Tumor Growth by Inhibiting eEF2K

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer deaths in the US due to the lack of effective targeted therapeutics and extremely poor prognosis.

OBJECTIVE

The study aims to investigate the role of miR-193b and related signaling mechanisms in PDAC cell proliferation, invasion, and tumor growth.

METHODS

Using PDAC cell lines, we performed cell viability, colony formation, in vitro wound healing, and matrigel invasion assays following transfection with miR-193b mimic or control-miR. To identify potential downstream targets of miR-193b, we utilized miRNA-target prediction algorithms and investigated the regulation of eukaryotic elongation factor-2 kinase (eEF2K) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways and mediators of epithelial mesenchymal transition (EMT). The role of miR-193b in PDAC tumorigenesis was evaluated in in vivo tumor growth of Panc-1 xenograft model in nude mice.

RESULTS

We found that miR-193b is under expressed in PDAC cells compared to corresponding normal pancreatic epithelial cells and demonstrated that ectopic expression of miR-193b reduced cell proliferation, migration, invasion, and EMT through downregulation of eEF2K signaling in PDAC cells. miR-193b expression led to increased expression of E-Cadherin and Claudin-1 while decreasing Snail and TCF8/ZEB1 expressions via eEF2K and MAPK/ERK axis. In vivo systemic injection of miR-193b using lipid-nanoparticles twice a week reduced tumor growth of Panc-1 xenografts and eEF2K expression in nude mice.

CONCLUSIONS

Our findings suggest that miR-193b expression suppresses PDAC cell proliferation, migration, invasion, and EMT through inhibition of eEF2K/MAPK-ERK oncogenic axis and that miR-193b-based RNA therapy might be an effective therapeutic strategy to control the growth of PDAC.

Prognostic value of microRNA-378 in esophageal cancer and its regulatory effect on tumor progression

The incidence and mortality rates of esophageal squamous cell carcinoma (ESCC) are high in China, which has increased the clinical and economic burden. The present study aimed to investigate the role of microRNA (miRNA/miR)-378 in ESCC. Reverse transcription-quantitative polymerase chain reaction analysis was performed to detect miR-378 expression in ESCC tissues and cell lines. Survival analysis was performed using the Kaplan-Meier method, while Cox regression analysis was performed to determine the prognostic value of miR-378 in ESCC. miR-378 mimic and miR-378 inhibitor was transfected into ESCC cells to overexpress or knockdown miR-378 expression levels in ESCC cells. The Cell Counting Kit-8 assay was performed to assess the proliferative ability of ESCC cells, while the Transwell assay was conducted to assess the effect of miR-378 on the migratory and invasive abilities of ESCC cells. The results demonstrated that miR-378 displayed significantly lower expression both in ESCC cells and tissues by comparison with those in normal cells and adjacent tissues. In addition, patients with low miR-378 expression had a worse prognosis and a shorter overall survival time than those with high miR-378 expression. Furthermore, low miR-378 expression promoted ESCC cell proliferation, migration and invasion. Taken together, the results of the present study suggest that miR-378 may act as a tumor suppressor in the occurrence and development of ESCC.

Cancer-associated fibroblasts-derived exosomal miR-3656 promotes the development and progression of esophageal squamous cell carcinoma via the ACAP2/PI3K-AKT signaling pathway

Esophageal squamous cell carcinoma (ESCC) is one of the most common gastrointestinal tumors, accounting for almost half a million deaths per year. Cancer-associated fibroblasts (CAFs) are the major constituent of the tumor microenvironment (TME) and dramatically impact ESCC progression. Recent evidence suggests that exosomes derived from CAFs are able to transmit regulating signals and promote ESCC development. In this study, we compared different the component ratios of miRNAs in exosomes secreted by CAFs in tumors and with those from normal fibroblasts (NFs) in precancerous tissues. The mRNA level of hsa-miR-3656 was significantly upregulated in the former exosomes. Subsequently, by comparing tumor cell development in vitro and in vivo, we found that the proliferation, migration and invasion capabilities of ESCC cells were significantly improved when miR-3656 was present. Further target gene analysis confirmed ACAP2 was a target gene regulated by miR-3656 and exhibited a negative regulatory effect on tumor proliferation. Additionally, the downregulation of ACAP2 triggered by exosomal-derived miR-3656 further promotes the activation of the PI3K/AKT and β-catenin signaling pathways and ultimately improves the growth of ESCC cells both in vitro and in xenograft models. These results may represent a potential therapeutic target for ESCC and provide a new basis for clinical treatment plans.

miR193b Promotes Apoptosis of Gastric Cancer Cells via Directly Mediating the Akt Pathway

Gastric cancer (GC) is one of the most common and fatal malignancies worldwide. MicroRNAs (miRNAs) play a critical role in tumor initiation, proliferation, and metastasis of gastric cancer. miR193b has been identified as a tumor suppressor in a variety of tumor types; however, its role in gastric cancer is yet to be determined. Here, we found a significant downregulation of miR193b expression in both human gastric cancer tissues (p < 0.05) and human gastric cancer cell lines (p < 0.01). Furthermore, the expression level of miR193b correlated with the tumor type, tumor size, and clinical stage (p < 0.05). In vitro, miR193b overexpression inhibited cell survival and induced apoptosis in GC cell lines, indicating that miR193b plays a role in the development of gastric cancer. KRAS was verified as the target of miR193b, and KRAS overexpression attenuated miR193b-induced apoptosis (p < 0.05). Moreover, we found that the Akt pathway negatively regulated miR193b, also affecting apoptosis. Further analyses indicated that PIK3CA mutation and KRAS amplification are two mutually exclusive pathways (p < 0.01), and we hypothesize that both two pathways could result in the carcinogenic overactivation of KRAS. Thus, our results suggest that the Akt-miR193b-KRAS axis may act as a mechanism affecting apoptosis in gastric cancer cells.

Biological Roles and Mechanisms of Circular RNA in Human Cancers

Circular RNA (circRNA) is an intriguing class of RNA with covalently closed-loop structure and is highly stable and conservative. As new members of the ncRNAs, the function, mechanism, potential diagnostic biomarker, and therapeutic target have raised increased attention. Most circRNAs are presented with characteristics of abundance, stability, conservatism, and often exhibiting tissue/developmental-stage-specific manner. Over 30,000 circRNAs have been identified with their unique structures to maintain stability more easily than linear RNAs. An increased numbers of circRNAs are dysregulated and involved in several biological processes of malignance, such as tumorigenesis, growth, invasion, metastasis, apoptosis, and vascularization. Emerging evidence suggests that circRNAs play important roles by acting as miRNA sponge or protein scaffolding, autophagy regulators, and interacting with RNA-binding protein (RBP), which may potentially serve as a novel promising biomarker for prevention, diagnosis and therapeutic target for treatment of human cancer with great significance either in scientific research or clinic arena. This review introduces concept, major features of circRNAs, and mainly describes the major biological functions and clinical relevance of circRNAs, as well as expressions and regulatory mechanisms in various types of human cancer, including pathogenesis, mode of action, potential target, signaling regulatory pathways, drug resistance, and therapeutic biomarkers. All of which provide evidence for the potential utilities of circRNAs in the diagnosis and treatment of cancer.

miR-193b Increases the Chemosensitivity of Osteosarcoma Cells by Promoting FEN1-Mediated Autophagy

Background

Osteosarcoma (OS) is one of the most common malignant bone tumors and specific microRNAs (miRNAs) are closely associated with malignant OS progression. In this study, we examined the role of microRNA-193b-3p (miR-193b) and the involvement of autophagy and apoptosis in the chemosensitivity of OS cells.

Methods

We employed qRT-PCR, Western blot, and immunohistochemistry to examine the expression levels of miR-193b, flap endonuclease 1 (FEN1), and autophagy-related proteins. Apoptosis was determined by flow cytometry using an Annexin V-FITC/PI apoptosis detection kit. Luciferase reporter assays confirmed the relationship between miR-193b and FEN1.

Results

miR-193b was downregulated in OS compared to adjacent normal tissues (p < 0.05). miR-193b overexpression in the OS cell lines induced autophagy and apoptosis, as shown by Western blotting and flow cytometry. Knockdown of FEN1, a structure-specific nuclease overexpressed in OS tissues (p < 0.001), induced apoptosis through activation of autophagy. Luciferase reporter assays confirmed that FEN1 is a direct target of miR-193b, FEN1 knockdown reinforced miR-193b induced apoptosis. Moreover, miR-193b expression enhanced epirubicin-induced autophagy and apoptosis.

Conclusion

Collectively, the results showed that miR-193b/FEN1 may serve as a novel therapeutic target for OS aimed mainly at the induction of autophagy and apoptosis. The miR-193b/FEN1 axis increased the chemosensitivity of OS cells, while activation of autophagy enhanced the anticancer effects of epirubicin.

The Emerging Role of Major Regulatory RNAs in Cancer Control

Alterations and personal variations of RNA interactions have been mechanistically coupled with disease etiology and phenotypical variations. RNA biomarkers, RNA mimics, and RNA antagonists have been developed for diagnostic, prognostic, and therapeutic uses. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are two major types of RNA molecules with regulatory roles, deregulation of which has been implicated in the initiation and progression of many human malignancies. Accumulating evidence indicated the clinical roles of regulatory RNAs in cancer control, stimulating a surge in exploring the functionalities of regulatory RNAs for improved understanding on disease pathogenesis and management. In this review, we highlight the critical roles of lncRNAs and miRNAs played in tumorigenesis, scrutinize their potential functionalities as diagnostic/prognostic biomarkers and/or therapeutic targets in clinics, outline opportunities that ncRNAs may bring to complement current clinical practice for improved cancer management and identify challenges faced by translating frontier knowledge on non-coding RNAs (ncRNAs) to bedside clinics as well as possible solutions.