miR-138 suppresses the proliferation of oral squamous cell carcinoma cells by targeting Yes-associated protein 1

MicroRNA-138 promotes the progression of multiple myeloma through targeting paired PAX5

BACKGROUND

Multiple myeloma cancer stem cells (MMSC) have been considered as the leading cause of multiple myeloma (MM) drug resistance and eventual relapse, microRNAs (miRNAs) collectively participate in the progression of MM. However, the pathogenesis of miR-138 in MMSC is still not fully understood.

OBJECTIVE

The intention of this study was to investigate the mechanism and role of miR-138 in multiple myeloma.

METHOD

Bone marrow samples and peripheral blood from patients and normal controls were collected. Use Magnet-based Cancer Stem Cell Isolation Kit to separate and extract MMSC. Real-time quantitative PCR (RT-qPCR) was carried out to determine mRNA level. Western blot was applied to detect protein levels. MTT and flow cytometry were conducted to examine the proliferation and apoptosis of MMSC. Finally, dual-luciferase reporter gene assays were performed to confirm that paired box 5 (PAX5) is a direct target for miR-138.

RESULTS

Compared with normal group, the expression of miR-138 in patients was significantly up-regulated, and the expression of miR-138 was in a negative correlation with PAX5. Additionally, downregulated miR-138 facilitated the apoptosis and inhibited the proliferation of MMSC in vitro and in vivo. Downregulated miR-138 moderated the expression of PAX5, Bcl-2, Bax, and Caspase-3. PAX5 was a direct target of miR-138.

CONCLUSION

Taken together, miR-138 plays a carcinogenic role in MM, and miR-138 adjusted the proliferation and apoptosis of MMSC by targeting PAX5. miR-138 has the probability of becoming a new medicinal target for the treatment of MM.

Unraveling the role of miRNAs in the diagnosis, progression, and drug resistance of oral cancer

Oral cancer (OC) is a widely observed neoplasm on a global scale. Over time, there has been an increase in both its fatality and incidence rates. Oral cancer metastasis is a complex process that involves a number of cellular mechanisms, including invasion, migration, proliferation, and escaping from malignant tissue through either lymphatic or vascular channels. MicroRNAs (miRNAs) are a crucial class of short non-coding RNAs recognized as significant modulators of diverse cellular processes and exert a pivotal influence on the carcinogenesis pathway, functioning either as tumor suppressors or as oncogenes. It has been shown that microRNAs (miRNAs) have a role in metastasis at several stages, including epithelial-mesenchymal transition, migration, invasion, and colonization. This regulation is achieved by targeting key genes involved in these pathways by miRNAs. This paper aims to give a contemporary analysis of OC, focusing on its molecular genetics. The current literature and emerging advancements in miRNA dysregulation in OC are thoroughly examined. This project would advance OC diagnosis, prognosis, therapy, and therapeutic implications.

Brucea javanica oil inhibits tongue squamous cell invasion and metastasis by regulating miR-138-EZH2 pathway

Tongue squamous cell carcinoma (TSCC) is one of the most common malignant tumors of head and neck. Its incidence is on the rise, and the proportion of young patients is gradually increasing, which is prone to tumor recurrence and metastasis. At present, there is no effective method to completely treat TSCC. Studies have shown that brucea javanica oil (BJO) has good antitumor activity against lung cancer and gastrointestinal tumors, but its therapeutic effect on TSCC is not clear. We have previously confirmed that oleic acid, the main component of BJO, can induce apoptosis of TSCC and reduce its invasion and metastasis ability. However, the anticancer effect and mechanism of BJO in TSCC remain unclear. In order to further explore the effects of BJO on the biological characteristics of TSCC cells, we studied the effects of different concentrations of BJO on the migration, invasion ability and epithelial mesenchymal transition (EMT) progression of TSCC cells and the possible mechanisms through in vitro experiments. We found that BJO could inhibit the invasion and metastasis of TSCC and up-regulate miR-138. After BJO treatment, the expression of E-cad was significantly increased, while the expression of EZH2, Slug, p-ERK1/2 and Vimentin was significantly decreased. EZH2 is a miR-138 target gene involved in TSCC. BJO inhibits TSCC invasion and metastasis by regulating the miR-138-EZH2 pathway. In vivo experiments have also well demonstrated the targeting effect of this pathway. This study provides a new therapeutic strategy for the treatment of TSCC.

Aberrant expression of miR-138 as a novel diagnostic biomarker in systemic sclerosis

BACKGROUND

MicroRNAs are short nucleotide sequences that contribute to the regulation of various biological functions and therefore their roles have been investigated in many pathologic conditions such as epithelial to mesenchymal transition in cancer and fibrosis; among them, miR-138 has been mostly studied in cancer biology and is well-known for its suppressing effect on cancer progression. Being able to suppress major pathways involved in EMT, miR-138 could be a good candidate to be investigated in fibrotic responses too. Based on our previous studies, and the capability of miR-138 to target and regulate several components of the EMT pathway; we hypothesized a role for miR-138 in systemic sclerosis. Accordingly, the gene expression of miR-138 was assessed to find any alterations in the whole blood of the SSc patients.

METHODS

Blood was collected from 70 patients with systemic sclerosis (equally divided between 2 groups of limited and diffuse categories) and 30 healthy individuals as controls. RNA was immediately isolated from the fresh whole blood; afterward, the resulting RNA was reverse transcribed into cDNA and then the relative expression of miR-138 was compared between the patients and the controls by the means of qPCR, and specific TaqMan primer and probes.

RESULTS

The relative expression of miR-138 was significantly lower in patients with systemic sclerosis compared to the controls. No significant difference was observed between the limited and diffuse patient groups. ROC curve analysis showed an appropriate diagnostic value of miR-138 in effectively differentiating SSc patients from the healthy controls.

CONCLUSION

miR-138 is likely involved in the pathogenesis of SSc and with further evaluations may be utilized as a diagnostic biomarker in SSc. Also, targeting miR-138 in future studies could be promising for finding a novel treatment option for patients with SSc.

miR-138-5p Inhibits the Growth and Invasion of Glioma Cells by Regulating WEE1

Background. Accumulating evidence has demonstrated the role of differentially expressed miRNAs in glioma progression. Our previous bioinformatics analyses revealed a role of miR-138-5p in glioma. miR-138-5p was decreased in various tumors, and He et al. found that miR-138-5p had an inhibitory effect on glioma cells in 2021. However, the role of miR-138-5p in the development of glioma and the underlying mechanism is unknown. In this study, we explored whether miR-138-5p affects the biology of glioma by regulating WEE1 expression. Methods. miR-138-5p and WEE1 G2 checkpoint kinase (WEE1) RNA and protein expression levels in glioma tissues were detected with qRT-PCR and western blotting, respectively. The effects of miR-138-5p and WEE1 on glioma cell migration and invasion were investigated using Transwell assays. CCK-8 assay was used to measure the effects of miR-138-5p and WEE1 on glioma cell proliferation. The mortality of glioma cells transfected with miR-138-5p and WEE1 was measured with flow cytometry. The relationship between miR-138-5p and WEE1 was explored using a luciferase reporter analysis. Results. Functional studies indicated that overexpression of miR-138-5p suppressed cell proliferation, migration, and invasion and promoted death in glioma cell lines. WEE1 was identified as a target of miR-138-5p, and overexpression of miR-138-5p significantly suppressed the levels of WEE1. Moreover, reintroduction of WEE1 partially abrogated miR-138-5p-induced suppression of motility and invasion in glioma cells. Conclusion. The low expression of miR-138-5p in glioma suggests a tumor suppressor role for this miRNA. miR-138-5p suppresses glioma progression by regulating WEE1. These data provide new insights into the molecular mechanism of glioma.

MicroRNA-134 inhibits tumor stem cell migration and invasion in oral squamous cell carcinomas via downregulation of PI3K-Akt signaling pathway by inhibiting LAMC2 expression

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most common malignant neoplasm of the mouth. Some studies have found that multiple microRNAs (miRs) participate in OSCC physiological and pathological processes.

METHODS

We explored the mechanism of action of miR-134 in OSCC involving the PI3K-Akt signaling pathway. Different bioinformatics methods were used to analyze the potential genes and their related miRs in OSCC. Tumor stem cells were separated from OSCCs through magnetic cell sorting. Regulatory pattern between miR-134 and LAMC2 in OSCC was evaluated by ectopic expression, knockdown and reporter assay experiments. The expression of miR-134, LAMC2, genes in PI3K-Akt signaling pathway, and apoptosis-related genes was detected. Cell proliferation was assessed by MTT assay, cell invasion by scratch test, cell migration by Transwell assay, cell cycle and apoptosis by flow cytometry, and cell growth and migration by xenograft tumor in nude mice. LAMC2 was predicted as the crucial factor related to OSCC using different chip data, and miR-134 was predicted to specifically bind LAMC2 in all five databases.

RESULTS

Overexpressed miR-134 or silenced LAMC2 was observed to inhibit cell proliferation, migration, invasion of OSCC cells, growth of subcutaneous xenograft in nude mice, as well as promote OSCC cell apoptosis. LAMC2, a target gene of miR-134, decreased following miR-134 promotion, while the PI3K-Akt signaling pathway was inactivated following LAMC2 knockdown. Furthermore, we also observed that the effect of overexpressed miR-134 was enhanced when LAMC2 was knocked down.

CONCLUSIONS

Taken together, these findings suggest that miR-134-mediated direct downregulation of LAMC2 inhibits migration and invasion of tumor stem cells in OSCC by suppressing the PI3K-Akt signaling pathway.

Upregulation of miR-138 Increases Sensitivity to Cisplatin in Hepatocellular Carcinoma by Regulating EZH2

Chemotherapeutic insensitivity is a major obstacle for effective treatment of hepatocellular carcinoma (HCC). Recently, new evidence showed that microRNAs (miRNAs) are closely related to drug sensitivity. This study aimed to investigate the relationship between miR-138 expression and cisplatin sensitivity of HCC cells by regulation of EZH2. CCK-8, EdU, and western blotting are determining the cell viability, proliferation, EZH2, and EMT-related protein expression. It was found that compared with normal samples, miR-138 expression was lower in cancer tissue; it was also downregulated in HCC cells. Transfected with miR-138 mimic increased sensitivity of HCC cells to cisplatin. Mechanistically, Luciferase Reporter analysis verified the interaction between miR-138 and target gene EZH2. Inhibition of EZH2 enhanced cisplatin sensitivity and transfection with EZH2 mimic mirrored the function of miR-138 in cisplatin sensitivity. Furthermore, the role of miR-138 on reversed cisplatin-induced epithelial–mesenchymal transition (EMT) was attenuated when combined with EZH2 plasmid. In conclusion, all data from this study illustrate that miR-138 may as a tumor suppressor provides a potential treatment method to treating HCC.

MicroRNAs as Modulators of Oral Tumorigenesis-A Focused Review

Oral cancers constitute the majority of head and neck tumors, with a relatively high incidence and poor survival rate in developing countries. While the five-year survival rates of the oral cancer patients have increased to 65%, the overall survival for advanced stages has been at 27% for the past ten years, emphasizing the necessity for further understanding the etiology of the disease, diagnosis, and formulating possible novel treatment regimens. MicroRNAs (miRNAs), a family of small non-coding RNA, have emerged as master modulators of gene expression in various cellular and biological process. Aberrant expression of these dynamic molecules has been associated with many human diseases, including oral cancers. The deregulated miRNAs have been shown to control various oncogenic processes, including sustaining proliferative signaling, evading growth suppressors, resisting cell death activating invasion and metastasis, and inducing angiogenesis. Hence, the aberrant expression of miRNAs associated with oral cancers, makes them potential candidates for the investigation of functional markers, which will aid in the differential diagnosis, prognosis, and development of novel therapeutic regimens. This review presents a holistic insight into our understanding of the role of miRNAs in regulating various hallmarks of oral tumorigenesis.

MicroRNA profile in the squamous cell carcinoma: prognostic and diagnostic roles

Head and neck squamous cell carcinomas (HNSCCs) are human malignancies associated with both genetic and environmental factors. MicroRNAs (miRNAs) as a group of small non-coding RNAs have prominent roles in the development of this kind of cancer. Expressions of several miRNAs have been demonstrated to be increased in HNSCC samples vs. non-malignant tissues. In silico prediction tools and functional analyses have confirmed the function of some miRNAs in the modulation of cancer-associated targets, thus indicating these miRNAs as onco-miRs. Moreover, numerous miRNAs have been down-regulated in HNSCC samples. Their targets mostly enhance cell proliferation or inhibit apoptosis. miRNAs signature has practical implications in the diagnosis, staging, and management of HNSC. Most notably, numerous miRNAs have been shown to alter response of tumor cells to anti-cancer drugs such as cisplatin and doxorubicin. Circulating levels of these small transcripts have been suggested as promising biomarkers for diagnosis of HNSCC. In the present manuscript, we sum up the available literature regarding the miRNAs signature in HNSCC and their role as diagnostic/prognostic biomarkers.

microRNAs in oral cancer: Moving from bench to bed as next generation medicine

Oral cancer is the thirteenth most common cancer in the world, with India contributing to 33% of the global burden. Lack of specific non-invasive markers, non-improvement in patient survival and tumor recurrence remain a major clinical challenge in oral cancer. Epigenetic regulation in the form of microRNAs (miRs) that act as tumor suppressor miRs or oncomiRs has gained significant momentum with the advancement in the field, suggesting the potential for clinical application of miRs in oral cancer. The current review of literature identified miR-21, miR-27a(-3p), miR-31, miR-93, miR-134, miR-146, miR-155, miR-196a, miR-196b, miR-211, miR-218, miR-222, miR-372 and miR-373 to be up-regulated and let-7a, let-7b, let-7c, let-7d, let-7e, let-7f, let-7g, let-7i, miR-26a, miR-99a-5p, miR-137, miR-139-5p, miR-143-3p, miR-184 and miR-375 to be down-regulated in oral cancer. Mechanistic studies have uncovered several miRs that are deregulated at varying levels and in different stages of oral cancer progression, thus providing clinical utility in better diagnosis as well as usefulness in prognosis by identifying patients with poor prognosis or stratifying patients based on responsiveness to chemo- and radio-therapy. Lastly, exogenous modulation of miR expression using miRNA-based drugs in combination with first-line agents may be adopted as a new therapeutic modality to treat oral cancer. Knowledge of miRs and their involvement in key molecular processes, clinical association, responsiveness to therapy and clinical advancement may highlight additional avenues in order to improve patient morbidity and mortality. Furthermore, combinatorial approaches with miR-therapy may be efficacious in oral cancer.

MicroRNA-138-5p Suppresses Non-small Cell Lung Cancer Cells by Targeting PD-L1/PD-1 to Regulate Tumor Microenvironment

Non-small cell lung cancer (NSCLC) is still challenging for treatment owing to immune tolerance and evasion. MicroRNA-138 (miR-138) not only acts as a tumor suppressor to inhibit tumor cell proliferation and migration but also regulates immune response. The regulatory mechanism of miR-138 in NSCLC remains not very clear. Herein, we demonstrated that miR-138-5p treatment decreased the growth of tumor cells and increased the number of tumor-infiltrated DCs. miR-138-5p not only down-regulated the expression of cyclin D3 (CCND3), CCD20, Ki67, and MCM in A549/3LL cells, but also regulated the maturation of DCs in A549-bearing nude mice and the 3LL-bearing C57BL/6 mouse model, and DCs’ capability to enhance T cells to kill tumor cells. Furthermore, miR-138-5p was found to target PD-L1 to down-regulate PD-L1 on tumor cells to reduce the expression of Ki67 and MCM in tumor cells and decrease the tolerance effect on DCs. miR-138-5p also directly down-regulates the expression of PD-L1 and PD-1 on DCs and T cells. Similar results were obtained from isolated human non-small cell lung cancer (NSCLC) cells and DCs. Thus, miR-138-5p inhibits tumor growth and activates the immune system by down-regulating PD-1/PD-L1 and it is a promising therapeutic target for NSCLC.

Noncoding RNAs in oral premalignant disorders and oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) has the highest mortality rate among all head and neck cancers and a relatively low five-year survival rate. Generally, the development of an oral mucosal malignancy represents a multistep process beginning with normal oral mucosa epithelium and culminating in OSCC after transitioning through intermediary oral premalignant disorders (OPMDs), during which dysplasia is often observed. Noncoding RNAs (ncRNAs) are RNAs that are not translated into proteins, but still can participate in regulating neoplastic cell behavior. Recently, data have emerged on the role of ncRNAs in the progression of oral mucosal malignant diseases, but the exact mechanisms through which ncRNAs are involved remain to be elucidated.

CONCLUSIONS

Knowledge on ncRNAs has added an extra layer of complexity to our understanding of the malignant progression of oral mucosal diseases. The identification of ncRNAs in multiple body fluids as biomarkers may provide new diagnostic options that can be used for the diagnosis and prognosis of OPMDs and OSCC, respectively. Despite overall advances that have been made in cancer treatment, the treatment options for OPMDs and OSCC are still limited. Several studies have shown that ncRNA-based treatment regimens may hold promise as alternative methods for treating OPMDs and OSCC. The use of ncRNAs as therapeutic agents, including miR-155, miR-34 and lncRNA HOTAIR, appear promising.

MicroRNA-138 inhibits tumor growth and enhances chemosensitivity in human cervical cancer by targeting H2AX

MicroRNA-138 (miR-138) acts as a key regulator in the modulation of carcinogenesis in numerous tumor types. Chemoresistance is common and relevant to the failure of multiple treatment strategies for cervical cancer. However, the biological role of miR-138 in the progression and chemosensitivity of cervical cancer is still unclear. The present study aimed to investigate the expression, function and mechanism of miR-138 in cervical cancer. An miR-138 mimic, inhibitor and negative control were transfected into SiHa and C33A cells. The expression of miR-138 and its target were assessed by reverse transcription-PCR, western blotting and immunohistochemistry. The functional significance of miR-138 in tumor progression and chemosensitivity to cisplatin in vitro was examined by Cell Counting Kit-8, flow cytometry, wound healing and Transwell assays. A tumor xenograft model was used to validate the effects in vivo. These results demonstrated that miR-138 was significantly downregulated in cervical cancer cells. Overexpression of miR-138 suppressed cervical cancer cell proliferation, invasion, increased apoptosis and enhanced chemotherapy sensitivity in vivo and in vitro. Furthermore, bioinformatics analysis and dual luciferase reporter assays demonstrated that H2AX served as a target for miR-138, and the rescue experiment revealed that H2AX was a functional target of miR-138. The protective effects of miR-138 overexpression were dependent on H2AX. This study provides evidence that miR-138/H2AX may be a novel therapeutic target in cervical cancer.

RP11-284F21.9 promotes oral squamous cell carcinoma development via the miR-383-5p/MAL2 axis

BACKGROUND

Increasing evidence suggests that dysregulated long non-coding RNAs (lncRNAs) are involved in tumorigenesis and progression. RP11-284F21.9, one of the temporally expressed S-phase lncRNAs in cancer cells, was recently identified by nascent RNA capture sequencing.

METHODS

Cal-27, Tca8113, SCC-9, HB56, and oral squamous cell carcinoma (OSCC) tissues were used in the experiment. RNA extraction, qRT-PCR, plasmid construction, cell proliferation, EdU labeling, Transwell migration, luciferase reporter, and western blotting were used to investigate the exact role and function of RP11-284F21.9 in cancer.

RESULTS

RP11-284F21.9 was upregulated in human OSCC samples and cell lines. RP11-284F21.9 depletion suppressed the proliferation, migration, and invasion of OSCC cell lines. There was interaction between RP11-284F21.9, miR-383-5p, and MAL2. Increased MAL2 and decreased miR-383-5p expression were also detected in OSCC tissues and cell lines. In addition, RP11-284F21.9 knockdown could reduce MAL2 expression, while miR-383-5p inhibitors abolished this repressive effect. RP11-284F21.9 acted as a competing endogenous RNA (ceRNA) of miR-383-5p, leading to MAL2 upregulation, and subsequently promoted OSCC progression.

CONCLUSION

RP11-284F21.9/miR-383-5p represents a novel and potential therapeutic target for the treatment of OSCC.

SIRT1 in the Development and Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. Current treatment options for inoperable HCCs have decreased therapeutic efficacy and are associated with systemic toxicity and chemoresistance. Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide–dependent enzyme that is frequently overexpressed in HCC, where it promotes tumorigenicity, metastasis, and chemoresistance. SIRT1 also maintains the tumorigenic and self-renewal proprieties of liver cancer stem cells. Multiple tumor-suppressive microRNAs (miRNAs) are downregulated in HCC and, as a consequence, permit SIRT1-induced tumorigenicity. However, either directly targeting SIRT1, combining conventional chemotherapy with SIRT1 inhibitors, or upregulating tumor-suppressive miRNAs may improve therapeutic efficacy and patient outcomes. Here, we present the interaction between SIRT1, miRNAs, and liver cancer stem cells and discuss the consequences of their interplay for the development and treatment of HCC.

Prospective applications of microRNAs in oral cancer

MicroRNAs (miRNAs) are non-coding RNA molecules that are generally encoded by endogenous genes and exert suppressive effects on post-transcriptional regulation of their target genes by translation repression or degradation of mRNA. This subsequently mediates activation or blocking of downstream signaling pathways associated with oral malignancies. Aberrant levels of certain miRNAs have been identified in cell experiments, clinical carcinomatous specimens, saliva, serum or plasma samples of patients with oral malignancies. miRNAs are associated with multiple aspects of oral cancer, including tumor growth, cellular proliferation, apoptosis, migration, invasion, metastasis, glycometabolism, radiosensitivity and chemosensitivity. miRNAs have the potential to be used in clinical applications as minimally invasive or non-invasive tools for early diagnosis and prognosis by the detection of serum, plasma and saliva levels, and may provide a new ancillary or additional reference index of traditional pathological grading and clinical staging. Furthermore, miRNAs may be used as prognostic biomarkers or targets for novel therapies for oral cancer.

microRNA-138 induces cell survival and reduces WNT/β-catenin signaling of osteoarthritis chondrocytes through NEK2

Osteoarthritis (OA) is a degenerative joint disease characterized by joint pain, stiffness, and function degeneration with high incidence. Recent studies have been inspired based on the association between microRNAs (miRs) and therapeutic research of OA. Hence, the present study evaluates the effects of miR-138 on chondrocyte proliferation, differentiation, and apoptosis through the WNT/β-catenin signaling pathway in mice with OA by binding to NIMA-related kinase 2 (NEK2). Appropriate dataset was selected from the Gene Expression Omnibus database, and differentially expressed genes and potential miRNAs that could regulate NEK2 were explored. A mouse model of OA was established. The expressions of miR-138, NEK2, β-catenin, GSK3β, Bcl-2, Bcl-2-associated X protein (Bax), p53, MMP-13, Col2, and Aggrecan and the phosphorylation levels of β-catenin were determined by the reverse transcription quantitative polymerase chain reaction and Western blot analysis. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and flow cytometry were employed to detect cell proliferation and apoptosis, respectively. The potential functional role of NEK2 was revealed to be related to the WNT/β-catenin signaling pathway, and miR-138 was the putative regulator of NEK2. miR-138 expression was downregulated while expressions of NEK2 and β-catenin as well as the phosphorylation levels of β-catenin were upregulated in mice with OA. The chondrocytes treated with miR-138 mimic and siRNA-NEK2 exhibited reduced expressions of NEK2, β-catenin, MMP-13, Bax, and p53 and elevated expressions of Col2, Aggrecan, and Bcl-2 as well as phosphorylation levels of β-catenin along with enhanced chondrocytes' proliferation and suppressed cell apoptosis. Overexpression of miR-138 induces cell survival and reduces WNT/β-catenin signaling of OA chondrocytes through NEK2. © 2019 IUBMB Life, 71(9):1355-1366, 2019.

Long non-coding RNA NEAT1 promotes migration and invasion of oral squamous cell carcinoma cells by sponging microRNA-365

Long non-coding RNA nuclear enriched abundant transcript 1 (NEAT1) has been demonstrated to serve key roles in numerous human cancer types, but its function in oral squamous cell carcinoma (OSCC) and underlying regulatory mechanism have not been evaluated. The present study demonstrated that expression of NEAT1 was significantly higher in OSCC tissue and cell lines compared with adjacent non-tumour tissue and normal oral keratinocytes, respectively. Additionally, upregulation of NEAT1 was significantly associated with advanced clinical stage and shorter survival time in patients with OSCC. Bioinformatics analysis and luciferase reporter gene assay data confirmed the interaction between NEAT1 and miR-365, and it was revealed that NEAT1 may downregulate microRNA (miR)-365 expression in OSCC cells. Furthermore, inhibition of NEAT1 expression led to a significant reduction in OSCC cell migration and invasion, which was accompanied by reduced matrix metalloproteinase (MMP)-2 and MMP9 protein expression. By contrast, inhibition of miR-365 eliminated suppressive effects of NEAT1 knockdown on OSCC cell migration and invasion. miR-365 was significantly downregulated in OSCC tissue and cell lines and an inverse correlation between miR-365 and NEAT1 expression in OSCC tissue was observed. To conclude, the present study demonstrated that NEAT1 promoted migration and invasiveness of OSCC cells by sponging miR-365. The current study suggests that NEAT1 may serve as a novel therapeutic target for the treatment of OSCC.

MicroRNA-138 acts as a tumor suppressor in non small cell lung cancer via targeting YAP1

MicroRNA (miR)-138 was found to have suppressive effects on the growth and metastasis of different human cancers. In this study, we aimed to investigate the regulatory mechanism of miR-138 in non-small cell lung cancer (NSCLC). We applied the Quantitative real-time PCR (qRT-PCR) to detect the miR-138 levels in NSCLC tissues (n=21) and cell lines, Bioinformatical predication, luciferase reporter assay and western blot to identify the target gene of miR-138. We also applied Cell transfection, MTT, transwell, and wound healing assays to reveal the role of miR-138 in NSCLC cell proliferation and malignant transformation. We observed that miR-138 expression level was significantly decreased in NSCLC tissues compared to their matched adjacent normal tissues. It was also downregulated in tissues with poor differentiation, advanced stage or lymph nodes metastasis, as well as in several NSCLC cell lines compared to normal lung epithelial cell. We further identified YAP1 as a direct target gene of miR-138, and observed that the protein level of YAP1 was negatively mediated by miR-138 in NSCLC A549 cells. Moreover, overexpression of miR-138 significantly inhibited A549 cell growth, invasion and migration, while knockdown of miR-138 enhanced such capacities. Further investigation showed that the cell proliferation capacity was higher in the miR-138+YAP1 group, when compared with that in the miR-138 group, suggesting that overexpression of YAP1 rescued the suppressive effects of miR-138 upregulation on NSCLC cell proliferation. However, we found no difference of cell invasion and migration capacities between miR-138+YAP1 group and miR-138 group. Finally, YAP1 was markedly upregulated in NSCLC tissues compared to their marched adjacent normal tissues. Its mRNA levels were reversely correlated with the miR-138 levels in NSCLC tissues. In summary, our study suggests that miR-138 may play a suppressive role in the growth and metastasis of NSCLC cells partly at least by targeting YAP1.

Long non-coding RNA H1 promotes cell proliferation and invasion by acting as a ceRNA of miR‑138 and releasing EZH2 in oral squamous cell carcinoma

Long non-coding RNAs (lncRNAs) have been shown to play pivotal roles in various types of human cancer, including oral squamous cell carcinoma (OSCC). However, the potential mechanisms of action of lncRNAs in OSCC remain to be fully elucidated. The aim of the present study was to further explore the potential mechanisms of action of lncRNAs in OSCC. We first analyzed Gene Expression Omnibus (GEO) datasets to investigate aberrantly expressed lncRNAs which may be involved in the development of OSCC. Reverse transcription‑quantitative PCR (RT‑qPCR) was performed to analyze the expression levels of lncRNA H19. In addition, the correlation between H19 expression and the clinical characteristics and prognosis of patients with OSCC was statistically analyzed. The effects of H19 expression on OSCC cells were examined by using overexpression and RNA interference approaches in vitro and in vivo. To examine the competitive endogenous RNA (ceRNA) mechanisms, bioinformatics analysis and luciferase reporter assay were performed. In addition, the correlation between H19 and microRNA (miR)‑138 was detected. H19 was found to be upregulated in OSCC tissues and its high expression level was associated with the TNM stage and nodal invasion, and also correlated with a shorter overall survival of patients with OSCC. The knockdown of H19 significantly inhibited OSCC cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT), and induced apoptosis in vitro; it also suppressed subcutaneous tumor growth in vivo. In addition, H19 was found to regulate the expression of oncogene enhancer of zeste homolog 2 (EZH2) by competing with miR‑138; the inhibition of miR‑138 attenuated the inhibitory effects of H19 knockdown on OSCC cells. On the whole, our findings suggest that H19 functions as an oncogene by inhibiting miR‑138 and facilitating EZH2 expression in OSCC. Thus, lncRNA H1 may represent a potential therapeutic target for OSCC.

Seven-microRNA panel for lung adenocarcinoma early diagnosis in patients presenting with ground-glass nodules

Background

MicroRNA (miRNA) expression is correlated with tumor histology, differentiation, invasiveness and treatment outcome. We aimed to identify miRNAs whose differential expression might enable early diagnosis of lung adenocarcinoma in patients presenting with ground-glass nodules (GGNs).

Methods

To identify potential miRNAs of interest, we analyzed the miRNA expression profile of tumor and adjacent non-para-tumor tissue in three participants by next-generation sequencing (NGS). We then assessed the expression levels of the miRNAs of interest in 73 lung adenocarcinomas presenting with GGNs with matched adjacent non-tumor tissue by quantitative real-time polymerase chain reaction (qRT-PCR). We also detected the miRNA panel in 66 lung benign diseases and 66 lung adenocarcinomas presenting with GGN lesion tissues by qRT-PCR. Target genes of our selected miRNA panel were predicted using Miranda with default parameters.

Results

Twenty-three miRNAs showed differential expression between tumor and adjacent non-tumor tissue by NGS. Five miRNAs exhibited higher expression in tumor tissue compared to adjacent non-tumor tissue (P<0.05); 18 miRNAs demonstrated lower expression in tumor tissue versus adjacent non-tumor tissue (P<0.05). When qRT-PCR was performed for the 23 miRNAs identified by NGS in the pilot stage, seven were found to have statistically significant expression in tumor versus adjacent non-tumor tissue (P<0.05). The sensitivity and specificity of seven-miRNA panel were 86.4% and 60.6%, respectively.

Conclusion

The predicted targets of our miRNAs of interest are frequently associated with cancer signaling pathways. We developed a miRNA panel that could potentially predict the presence of lung adenocarcinoma in patients presenting with GGNs.

"Omics" in oral cancer: New approaches for biomarker discovery

OBJECTIVES

In this review paper, we explored the application of "omics" approaches in the study of oral cancer (OC). It will provide a better understanding of how "omics" approaches may lead to novel biomarker molecules or molecular signatures with potential value in clinical practice. A future direction of "omics"-driven research in OC is also discussed.

METHODS

Studies on "omics"-based approaches [genomics/proteomics/transcriptomics/metabolomics] were investigated for differentiating oral squamous cell carcinoma,oral sub-mucous fibrosis, oral leukoplakia, oral lichen planus, oral erythroplakia from normal cases. Electronic databases viz., PubMed, Springer, and Google Scholar were searched.

RESULTS

One eighty-one studies were included in this review. The review shows that the fields of genomics, transcriptomics, proteomics, and metabolomics-based marker identification have implemented advanced tools to screen early changes in DNA, RNA, protein, and metabolite expression in OC population.

CONCLUSIONS

It may be concluded that despite advances in OC therapy, symptomatic presentation occurs at an advanced stage, where various curative treatment options become very limited. A molecular level study is essential for detecting an OC biomarker at an early stage. Modern "Omics" strategies can potentially make a major contribution to meet this need.

MicroRNA-138 targets SP1 to inhibit the proliferation, migration and invasion of hepatocellular carcinoma cells

The identification of microRNAs (miRNAs/miRs) has enabled the improved understanding of the carcinogenesis and progression of hepatocellular carcinoma (HCC). miRNAs are small non-coding RNAs comprised of 19-24 nucleotides that regulate the expression of target genes. In the present study, miR-138 was demonstrated to be downregulated in human HCC tissues and cell lines. Restoration of miR-138 expression repressed the proliferation, migration and invasion of HCC cells. Furthermore, specificity protein 1 (SP1) was identified as a target gene of miR-138 in HCC using bioinformatics analysis, luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction and western blot analysis. Knockdown of SP1 produced similar suppressive effects to those induced by miR-138 overexpression in HCC cells. These results indicate that miR-138 targeted SP1 to repress the growth, migration and invasion of HCC cells, and may therefore represent a therapeutic target in human HCC.

MicroRNA-138 suppresses cell proliferation and invasion of renal cell carcinoma by directly targeting SOX9

An accumulating number of studies have reported that the expression levels of microRNAs (miRNAs/miRs) are dysregulated in a variety of human cancer types, including renal cell carcinoma (RCC). miRNAs play essential functions in tumorigenesis and the progression of tumors by serving as oncogenes or tumor suppressors. Recently, the expression and functions of miR-138 have been studied in a number of human cancer types; however, its role in RCC remains poorly understood. In the present study, the results revealed that miR-138 was significantly downregulated in RCC cell lines and tissues, and that low expression levels of miR-138 were correlated with histological grade, tumor stage and lymph node metastasis. In functional studies, restoration of miR-138 expression inhibited cell proliferation and invasion of ACHN and A498 cells. In addition, SOX9 was validated as a direct target gene of miR-138 in RCC. SOX9 knockdown inhibited cell proliferation and invasion of RCC, with a similar effect to that induced by miR-138, rendering SOX9 a functional target of miR-138 in the disease. These findings indicate that miR-138 may present a novel target for therapeutic strategies in RCC.

Fascin promotes migration and invasion and is a prognostic marker for oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) prognosis is related to clinical stage and histological grade. However, this stratification needs to be refined. We conducted a comparative proteome study in microdissected samples from normal oral mucosa and OSCC to identify biomarkers for malignancy. Fascin and plectin were identified as differently expressed and both are implicated in several malignancies, but the clinical impacts of aberrant fascin and plectin expression in OSCCs remains largely unknown. Immunohistochemistry and real-time quantitative PCR were carried out in ex vivo OSCC samples and cell lines. A loss-of-function strategy using shRNA targeting fascin was employed to investigate in vitro and in vivo the fascin role on oral tumorigenesis. Transfections of microRNA mimics were performed to determine whether the fascin overexpression is regulated by miR-138 and miR-145. We found that fascin and plectin are frequently upregulated in OSCC samples and cell lines, but only fascin overexpression is an independent unfavorable prognostic indicator of disease-specific survival. In combination with advanced T stage, high fascin level is also an independent factor of disease-free survival. Knockdown of fascin in OSCC cells promoted cell adhesion and inhibited migration, invasion and EMT, and forced expression of miR-138 in OSCC cells significantly decreased the expression of fascin. In addition, fascin downregulation leads to reduced filopodia formation and decrease on paxillin expression. The subcutaneous xenograft model showed that tumors formed in the presence of low levels of fascin were significantly smaller compared to those formed with high fascin levels. Collectively, our findings suggest that fascin expression correlates with disease progression and may serve as a prognostic marker and therapeutic target for patients with OSCC.

MicroRNA-138 directly targets TNFAIP8 and acts as a tumor suppressor in osteosarcoma

MicroRNAs (miRs) have a critical role in the development and malignant progression of osteosarcoma (OS), but the underlying mechanisms have largely remained elusive. The present study aimed to explore the regulatory role of miR-138 in OS growth and metastasis and investigated the associated mechanisms. Reverse-transcription quantitative polymerase chain reaction and western blot analysis were performed to examine the miR-138 and protein expression levels in OS and normal bone tissues and cell lines. An MTT assay and a Transwell assay were used to assess cell proliferation and invasion. Flow cytometry was used to analyze the cell cycle and determine the apoptotic rate. A luciferase reporter assay was used to confirm the targeting association between miR-138 and tumor necrosis factor-α-induced protein 8 (TNFAIP8). It was found that miR-138 was downregulated in OS tissues and cell lines. Overexpression of miR-138 decreased the proliferation, cell cycle progression and invasion of OS cells, while inducing cell apoptosis. TNFAIP8 was then identified as a novel target of miR-138. Similarly to the effects of miR-138 overexpression, inhibition of TNFAIP8 also inhibited OS cell proliferation, cell cycle progression and invasion, and induced cell apoptosis. In addition, miR-138 overexpression as well as downregulation of TNFAIP8 reduced OS cell invasion via inhibition of matrix metalloproteinase-2 and −9 expression. Taken together, the results of the present study demonstrated that miR-138 directly targets TNFAIP8 and acts as a tumor suppressor in OS, suggesting that the miR-138/TNFAIP8 interaction may become a promising therapeutic target for OS.

MicroRNA-138 suppresses cell proliferation in laryngeal squamous cell carcinoma via inhibiting EZH2 and PI3K/AKT signaling

MicroRNA (miR)-138 generally has a suppressive role in various human cancer types; however, its role and the underlying mechanisms in laryngeal squamous cell carcinoma (LSCC) have remained to be elucidated. The present study assessed the clinical significance and regulatory mechanisms of miR-138 in LSCC progression. Reverse-transcription quantitative polymerase chain reaction analysis indicated that miR-138 was significantly downregulated in LSCC tissues and cell lines. In addition, the decreased expression of miR-138 was significantly associated with poor differentiation, lymph node metastasis and advanced clinical stage of LSCC. Restoration of miR-138 expression caused a significant decrease in the proliferation of Hep-2 LSCC cells, while knockdown of miR-138 significantly promoted Hep-2 cell proliferation. A luciferase reporter assay further identified enhancer of zeste homologue 2 (EZH2) as a direct target gene of miR-138, and the protein expression of EZH2 was negatively regulated by miR-138 in Hep-2 cells. Furthermore, overexpression of EZH2 eliminated the suppressive effects of miR-138 on Hep-2 cell proliferation via activation of phosphoinositide-3 kinase (PI3K)/AKT signaling. In addition, EZH2 was found to be significantly upregulated in LSCC tissues and to be inversely correlated to the miR-138 levels. The results of the present study demonstrated that miR-138 inhibits the proliferation of LSCC cells, at least partly via targeting EZH2 and inhibiting PI3 K/AKT signaling. The present study highlighted the clinical significance of the miR-138/EZH2 axis in LSCC.

MicroRNA-138 inhibits cell proliferation in hepatocellular carcinoma by targeting Sirt1

MicroRNAs (miRNAs) are a family of small, non‑coding RNA molecules that are highly conserved across species and function as regulators of gene expression. In the present study, we revealed that miR-138 expression was at a low level while sirtuin type 1 (Sirt1) mRNA expression was at high level in hepatocellular carcinoma tissues and cell lines by using real-time PCR and western blot assays, and the functions of miR-138 were achieved via targeting of Sirt1 using luciferase reporter gene vector and RNA immunoprecipitation assays. Overexpression of miR-138 attenuated Sirt1 expression and inhibited cell proliferation by using CCK-8 and BrdU assays. The inhibitory effect of miR-138 could be partially restored by forced expression of Sirt1 in cells. Our data revealed a crucial role and mechanism of miR-138 in the regulation of hepatocellular carcinoma cell growth via the miR-138/Sirt1 axis, and miR-138 could be an important potential target for the clinical management of hepatocellular carcinoma in the future.

miR-138 inhibits gastric cancer growth by suppressing SOX4

MicroRNA-138 (miR-138) has been reported to be downregulated and function as a tumor suppressor in several cancers. However, the role and molecular mechanisms of miR-138 in the progression of gastric cancer (GC) remain to be clarified. The aim of the present study was to determine the role of miR-138 in GC progression. In the present study we found that miR-138 expression was downregulated in GC tissues and cell lines. Statistical analysis demonstrated that low expression levels of miR-138 were associated with advanced tumor-node-metastasis (TNM) stage, and lymph node metastasis. Function assays demonstrated that overexpression of miR-138 impaired GC cell proliferation, colony formation, migration and invasion in vitro, as well as suppressed tumor growth in vivo. Through reporter gene, qRT-PCR and western blot assays, SRY-related high mobility group box 4 (SOX4), a master mediator in epithelial-mesenchymal transition (EMT), was confirmed to be a direct target of miR-138 in GC cells. Western blot assay revealed that miR-138 overexpression inhibited EMT procession in GC cells by upregulation of epithelial marker E-cadherin and downregulation of mesenchymal markers, N-cadherin and vimentin. Furthermore, the levels of miR-138 were inversely correlated with those of SOX4 expression in GC tissues. Overexpression of SOX4 rescued the inhibition effect in GC cells caused by miR-138. Collectively, these findings indicate that miR-138 may be a potential therapeutic target for GC.

Suppressive effect of microRNA-138 on the proliferation and invasion of osteosarcoma cells via targeting SIRT1

MicroRNAs (miRs), a class of small non-coding RNAs, function as key regulators in gene expression through binding to the 3'-untranslated region (UTR) of their target mRNA, which further leads to translational repression or mRNA degradation. Recently, miR-138 has been found to have a tumor suppressive role in a variety of human malignancies. However, the exact role of miR-138 in regulating the malignant phenotypes of osteosarcoma (OS) has remained to be elucidated. In the present study, reverse-transcription PCR analysis showed that the expression of miR-138 was markedly reduced in OS tissues compared to that in matched adjacent non-tumorous tissues. Furthermore, it was also downregulated in several common OS cell lines, when compared with that in a normal human osteoblast cell line. Overexpression of miR-138 suppressed cell proliferation and invasion and led to a significant decrease in the protein expression of sirtuin 1 (SIRT1), which was further identified as a direct target gene of miR-138 in MG63 cells. Moreover, restoration of SIRT1 expression reversed the suppressive effects of miR-138 on MG63 cell proliferation and invasion. Finally, the expression of SIRT1 was found to be significantly upregulated in OS tissues compared to that in matched adjacent tissues, and SIRT1 levels were inversely correlated with the miR-138 levels in OS tissues. Therefore, the present study demonstrated that miR-138 has a role in inhibiting OS cell proliferation and invasion via directly targeting SIRT1, and suggested that the miR-138/SIRT1 axis may become a promising therapeutic target for OS.

MiR-138: A promising therapeutic target for cancer

MicroRNAs are small noncoding RNAs which regulate gene expressions at post-transcriptional level by binding to the 3'-untranslated region of target messenger RNAs. Growing evidences highlight their pivotal roles in various biological processes of human cancers. Among them, miR-138, generating from two primary transcripts, pri-miR-138-1 and pri-miR-138-2, expresses aberrantly in different cancers and is extensively studied in cancer network. Importantly, studies have shown that miR-138 acts as a tumor suppressor by targeting many target genes, which are related to proliferation, apoptosis, invasion, and migration. Additionally, some researches also discover that miR-138 can sensitize tumors to chemotherapies. In this review, we summarize the expression of miR-138 on regulatory mechanisms and tumor biological processes, which will establish molecular basis on the usage of miR-138 in clinical applications in the future.

Emerging Roles of Epigenetic Regulator Sin3 in Cancer

Revolutionizing treatment strategies is an urgent clinical need in the fight against cancer. Recently the scientific community has recognized chromatin-associated proteins as promising therapeutic candidates. However, there is a need to develop more targeted epigenetic inhibitors with less toxicity. Sin3 family is one such target which consists of evolutionary conserved proteins with two paralogues Sin3A and Sin3B. Sin3A/B are global transcription regulators that provide a versatile platform for diverse chromatin-modifying activities. Sin3 proteins regulate key cellular functions that include cell cycle, proliferation, and differentiation, and have recently been implicated in cancer pathogenesis. In this chapter, we summarize the key concepts of Sin3 biology and elaborate the recent advancements in the role of Sin3 proteins in cancer with specific examples in multiple endocrine neoplasia type 2, pancreatic ductal adenocarcinoma, and triple negative breast cancer. Finally, a program to create an integrative approach for screening antitumor agents that target chromatin-associated factors like Sin3 is presented.

RETRACTED: MicroRNA-138 modulates metastasis and EMT in breast cancer cells by targeting vimentin

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concerns were raised in the public domain and also reported by the authors to the journal regarding the similarity between panels from Figures 3A and 4C. In addition to the institutional investigation, the journal requested the authors to provide the raw data. However, the authors have not fulfilled this request, and therefore the Editor-in-Chief decided to retract the article.