Downregulation of miR-221 Inhibits Cell Migration and Invasion through Targeting Methyl-CpG Binding Domain Protein 2 in Human Oral Squamous Cell Carcinoma Cells

Protumorigenic role of the atypical cadherin FAT1 by the suppression of PDCD10 via RelA/miR221-3p/222-3p axis in glioblastoma

The atypical cadherin FAT1 function either as a pro or antitumorigenic in tumors of different tissue origins. Our group previously demonstrated the protumorigenic nature of FAT1 signaling in glioblastoma (GBM). In this study, we investigated how FAT1 influences the expression of clustered oncomiRs (miR-221-3p/miR-222-3p) and their downstream effects in GBM. Through several experiments involving the measurement of specific gene/microRNA expression, gene knockdowns, protein and cellular assays, we have demonstrated a novel oncogenic signaling pathway mediated by FAT1 in glioma. These results have been verified using antimiRs and miR-mimic assays. Initially, in glioma-derived cell lines (U87MG and LN229), we observed FAT1 as a novel up-regulator of the transcription factor NFκB-RelA. RelA then promotes the expression of the clustered-oncomiRs, miR-221-3p/miR-222-3p, which in turn suppresses the expression of the tumor suppressor gene (TSG), PDCD10 (Programmed cell death protein10). The suppression of PDCD10, and other known TSG targets (PTEN/PUMA), by miR-221-3p/miR-222-3p, leads to increased clonogenicity, migration, and invasion of glioma cells. Consistent with our in-vitro findings, we observed a positive expression correlation of FAT1 and miR-221-3p, and an inverse correlation of FAT1 and the miR-targets (PDCD10/PTEN/PUMA), in GBM tissue-samples. These findings were also supported by publicly available GBM databases (The Cancer Genome Atlas [TCGA] and The Repository of Molecular Brain Neoplasia Data [Rembrandt]). Patients with tumors displaying high levels of FAT1 and miR-221-3p expression (50% and 65% respectively) experienced shorter overall survival. Similar results were observed in the TCGA-GBM database. Thus, our findings show a novel FAT1/RelA/miR-221/miR-222 oncogenic-effector pathway that downregulates the TSG, PDCD10, in GBM, which could be targeted therapeutically in a specific manner.

MiRNA-related metastasis in oral cancer: moving and shaking

Across the world, oral cancer is a prevalent tumor. Over the years, both its mortality and incidence have grown. Oral cancer metastasis is a complex process involving cell invasion, migration, proliferation, and egress from cancer tissue either by lymphatic vessels or blood vessels. MicroRNAs (miRNAs) are essential short non-coding RNAs, which can act either as tumor suppressors or as oncogenes to control cancer development. Cancer metastasis is a multi-step process, in which miRNAs can inhibit or stimulate metastasis at all stages, including epithelial-mesenchymal transition, migration, invasion, and colonization, by targeting critical genes in these pathways. On the other hand, long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), two different types of non-coding RNAs, can regulate cancer metastasis by affecting gene expression through cross-talk with miRNAs. We reviewed the scientific literature (Google Scholar, Scopus, and PubMed) for the period 2000-2023 to find reports concerning miRNAs and lncRNA/circRNA-miRNA-mRNA networks, which control the spread of oral cancer cells by affecting invasion, migration, and metastasis. According to these reports, miRNAs are involved in the regulation of metastasis pathways either by directly or indirectly targeting genes associated with metastasis. Moreover, circRNAs and lncRNAs can induce or suppress oral cancer metastasis by acting as competing endogenous RNAs to inhibit the effect of miRNA suppression on specific mRNAs. Overall, non-coding RNAs (especially miRNAs) could help to create innovative therapeutic methods for the control of oral cancer metastases.

Oral Cancer Cells Release Vesicles that Cause Pain

Oral cancer pain is attributed to the release from cancers of mediators that sensitize and activate sensory neurons. Intraplantar injection of conditioned media (CM) from human tongue cancer cell line HSC-3 or OSC-20 evokes nociceptive behavior. By contrast, CM from noncancer cell lines, DOK, and HaCaT are non-nociceptive. Pain mediators are carried by extracellular vesicles (EVs) released from cancer cells. Depletion of EVs from cancer cell line CM reverses mechanical allodynia and thermal hyperalgesia. CM from non-nociceptive cell lines become nociceptive when reconstituted with HSC-3 EVs. Two miRNAs (hsa-miR-21-5p and hsa-miR-221-3p) are identified that are present in increased abundance in EVs from HSC-3 and OSC-20 CM compared to HaCaT CM. The miRNA target genes suggest potential involvement in oral cancer pain of the toll like receptor 7 (TLR7) and 8 (TLR8) pathways, as well as signaling through interleukin 6 cytokine family signal transducer receptor (gp130, encoded by IL6ST) and colony stimulating factor receptor (G-CSFR, encoded by CSF3R), Janus kinase and signal transducer and activator of transcription 3 (JAK/STAT3). These studies confirm the recent discovery of the role of cancer EVs in pain and add to the repertoire of algesic and analgesic cancer pain mediators and pathways that contribute to oral cancer pain.

miR221 regulates cell migration by targeting annexin a1 expression in human mesothelial MeT-5A cells neoplastic-like transformed by multi-walled carbon nanotube

Background

Multi-walled carbon nanotube (MWCNT) is one of the most widely used manufactured nanomaterials, however, its potential harmful effect on human health is of great concern. Previously we have shown the acute and chronic exposure to MWCNT induced different responses in human mesothelial MeT-5A cells. In the current study, MeT-5A cells were continuously subjected to MWCNT exposure at 10 μg/cm² for 48 h per passage, up to a whole year, to further clarify the carcinogesis and its potential mechanisms of MWCNT.

Results

After one-year MWCNT treatment, MeT-5A cells exhibited neoplastic-like properties, including morphological changes, anchorage-independent growth, increased cell proliferation and cell migration. Further examination revealed the expression of microRNA 221 (miR221) was gradually decreased, while the annexin a1 expression was increased at both the mRNA and protein level during the exposure. Bioinformatic analysis indicated that annexin a1 is a target for miR221 regulation, and it was confirmed by transfecting cells with miR221 mimics, which resulted in the downregulation of annexin a1. Detailed analyses demonstrated miR221 was involved in the regulation of cell migration, e.g., downregulation of miR221 or overexpression of ANNEXIN A1, contributed to the increased cell migration. In contrast, overexpression of miR221 or downregulation of ANNEXIN A1 slowed cell migration.

Conclusions

Taken together, these results point to a neoplastic-transforming property of MWCNT, and the miR221-annexin a1 axis is involved in the regulation of cell migration in the transformed cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41021-021-00209-y.

MicroRNAs: The Link between the Metabolic Syndrome and Oncogenesis

Metabolic syndrome (MetS) represents a cluster of disorders that increase the risk of a plethora of conditions, in particular type two diabetes, cardiovascular diseases, and certain types of cancers. MetS is a complex entity characterized by a chronic inflammatory state that implies dysregulations of adipokins and proinflammatory cytokins together with hormonal and growth factors imbalances. Of great interest is the implication of microRNA (miRNA, miR), non-coding RNA, in cancer genesis, progression, and metastasis. The adipose tissue serves as an important source of miRs, which represent a novel class of adipokines, that play a crucial role in carcinogenesis. Altered miRs secretion in the adipose tissue, in the context of MetS, might explain their implication in the oncogenesis. The interplay between miRs expressed in adipose tissue, their dysregulation and cancer pathogenesis are still intriguing, taking into consideration the fact that miRNAs show both carcinogenic and tumor suppressor effects. The aim of our review was to discuss the latest publications concerning the implication of miRs dysregulation in MetS and their significance in tumoral signaling pathways. Furthermore, we emphasized the role of miRNAs as potential target therapies and their implication in cancer progression and metastasis.

lncRNA XIST regulates cell proliferation, migration and invasion via regulating miR-30b and RECK in nasopharyngeal carcinoma

Long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) plays an essential role in the development and progress of nasopharyngeal carcinoma (NPC). MicroRNA-30b (miR-30b) has been confirmed to play an inhibitory role in various types of cancer. The molecular mechanisms underlying the lncRNA XIST-mediated regulation of the metastasis of NPC cells by miR-30b is not clear. qPCR and western blot analysis were used to detect the expression of XIST, miR-30b, and reversion inducing cysteine rich protein with kazal motifs (RECK) in NPC tissues and cell lines. The detection of luciferase reporter gene confirmed the relationship between lncRNA XIST, miR-30b and RECK. CCK-8 and Transwell assays were performed in order to detect the proliferation, migration and invasion of the NPC cells. The results of qPCR and western blotting indicated that the expression levels of lncRNA XIST and RECK were higher in the NPC tissues and cell lines than that of the control group, while the expression of miR-30b was lower. Knockdown of lncRNA XIST significantly inhibited cell proliferation, migration and invasion in the NPC cell lines. In addition, lncRNA XIST was found to negatively regulate the expression of miR-30b, resulting in the upregulation of RECK. Overexpression of RECK was found to reverse the inhibitory effect of lncRNA XIST knockdown or miR-30b on NPC cell metastasis. Our results showed that cell migration and invasion were inhibited by knockdown of lncRNA XIST, suggesting that the lncRNA XIST/miR-30b/RECK axis is involved in the development of NPC.

The roles of microRNAs in the stemness of oral cancer cells

Oral cancer (OC), which is the most common form of head and neck cancers, has one of the lowest (~50%) overall 5-year survival rates. The main reasons for this high mortality rate are diagnosis of OC in advanced stages in most patients and spread to distant organs via lymph node metastasis. Many studies have shown that a small population of cells within the tumor plays vital roles in the initiation, progression, and metastasis of the tumor, resistance to chemotherapeutic agents, and recurrence. These cells, identified as cancer stem cells (CSCs), are the main reasons for the failure of current treatment modalities. Deregulated expressions of microRNAs are closely related to tumor prognosis, metastasis and drug resistance. In addition, microRNAs play important roles in regulating the functions of CSCs. Until now, the roles of microRNAs in the acquisition and maintenance of OC stemness have not been elucidated in detail yet. Here in this review, we summarized significant findings and the latest literature to better understand the involvement of CSCs in association with dysregulated microRNAs in oral carcinogenesis. Possible roles of these microRNAs in acquisition and maintenance of CSCs features during OC pathogenesis were summarized.

Regulation of DNA methylation machinery by epi-miRNAs in human cancer: emerging new targets in cancer therapy

Disruption in DNA methylation processes can lead to alteration in gene expression and function that would ultimately result in malignant transformation. In this way, studies have shown that, in cancers, methylation-associated silencing inactivates tumor suppressor genes, as effectively as mutations. DNA methylation machinery is composed of several genes, including those with DNA methyltransferases activity, proteins that bind to methylated cytosine in the promoter region, and enzymes with demethylase activity. Based on a prominent body of evidence, DNA methylation machinery could be regulated by microRNAs (miRNAs) called epi-miRNAs. Numerous studies demonstrated that dysregulation in DNA methylation regulators like upstream epi-miRNAs is indispensable for carcinogenesis; consequently, the malignant capacity of these cells could be reversed by restoring of this regulatory system in cancer. Conceivably, recognition of these epi-miRNAs in cancer cells could not only reveal novel molecular entities in carcinogenesis, but also render promising targets for cancer therapy. In this review, at first, we have an overview of the methylation alteration in cancers, and the effect of this phenomenon in miRNAs expression and after that, we conduct an in-depth discussion about the regulation of DNA methylation regulators by epi-miRNAs in cancer cells.

LncRNA CASC15 Functions As An Unfavorable Predictor Of Ovarian Cancer Prognosis And Inhibits Tumor Progression Through Regulation Of miR-221/ARID1A Axis

Background

LncRNA cancer susceptibility candidate 15 (CASC15) has been demonstrated to act as an oncogene in different cancers; however, its role in ovarian cancer remains elusive.

Methods

Quantitative real-time PCR (qRT-PCR) was performed to examine the expression of lncRNA CASC15. Kaplan–Meier survival analysis was performed to evaluate the prognostic significance of lncRNA CASC15. CCK-8, soft-agar colony-formation, flow cytometry, transwell migration and invasion assays were used to analyze the biological behavior of lncRNA CASC5 in ovarian cancer. Furthermore, the potential mechanism of lncRNA CAC15 was investigated by bioinformatics analysis, luciferase reporter assay, and biotin pull-down assay.

Results

In this study, we found that the expression of CASC15 was lower in ovarian cancer tissues and cells by qRT-PCR. In addition, low expression of CASC15 was closely correlated with advanced TNM stage, moderate/poor differentiation, and larger size. Moreover, Kaplan–Meier survival analysis showed that patients with low CASC15 expression level had poorer overall survival and progression-free survival than those with high CASC15 expression. Meanwhile, ROC analysis found that CASC15 had diagnostic values to distinguish tumor tissues from nontumorous tissues. Overexpression of CASC15 prohibited the malignancy of ovarian cancer cells, including proliferation, colony formation, cell cycle, migration, and invasion, and promoted cell apoptosis. In addition, bioinformatics analysis, luciferase reporter assay, and biotin pull-down assay confirmed that CASC15 straightly interacted with miR-221. We also observed that ARID1A was a downstream target of miR-221 and CASC15 subsequently exerted its tumor-suppressive effects by regulating the expression of ARID1A in ovarian cancer cells.

Conclusion

Overall, this study firstly elucidated that CASC15 could play a tumor-suppressive role in ovarian cancer by the regulation of CASC15/miR-221/ARID1A axis, which may provide a ponderable prognostic biomarker and promising therapeutic target for treatment of patients with ovarian cancer.

miR‑148a modulates the viability, migration and invasion of oral squamous cell carcinoma cells by regulating HLA‑G expression

Oral squamous cell carcinoma (OSCC) is a common malignancy of the oral and maxillofacial regions. MicroRNAs (miRs) are a group of endogenous small noncoding RNAs that inhibit gene expression by binding to the mRNA of target genes, and serve important roles in numerous biological processes. Reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect gene and protein expression levels, respectively. Cell proliferation, migration and invasion were detected using MTT, wound healing and Matrigel assays, respectively. The association between miR-148a and human leukocyte antigen-G (HLA-G) was analyzed using Targetscan and Luciferase reporter assays. In the present study, miR-148a was revealed to be significantly downregulated in OSCC cells. To further investigate the functions of miR-148a in OSCC, the viability, migration, and invasive abilities of SCC-9 cells were investigated following transfection with miR-148a mimics or miR-148a inhibitor. It was revealed that transfection with miR-148a mimics significantly reduced the viability, migration and invasion of cells, whereas miR-148a inhibitor significantly enhanced these properties. In addition, HLA-G was identified as a direct target of miR-148a and demonstrated to be downregulated in OSCC cells. Furthermore, it was revealed that transfection with miR-148a mimics decreased the expression levels of HLA-G mRNA and protein in SCC-9 cells, whereas transfection with miR-148a inhibitor increased the expression of HLA-G mRNA and protein. The results indicated that there was an association between miR-148a and HLA-G expression, and suggested that miR-148a may be a potential target in the treatment of OSCC.

* Glioblastoma Exosomes for Therapeutic Angiogenesis in Peripheral Ischemia

Peripheral ischemia as a result of occlusive vascular disease is a widespread problem in patients older than the age of 65. Angiogenic therapies that can induce microvascular growth have great potential for providing a long-lasting solution for patients with ischemia and would provide an appealing alternative to surgical and percutaneous interventions. However, many angiogenic therapies have seen poor efficacy in clinical trials, suggesting that patients with long-term peripheral ischemia have considerable therapeutic resistance to angiogenic stimuli. Glioblastoma is one of the most angiogenic tumor types, inducing robust vessel growth in the area surrounding the tumor. One major angiogenic mechanism used by the tumor cells to induce blood vessel growth is the production of exosomes and other extracellular vesicles that can carry pro-angiogenic and immunomodulatory signals. Here, we explored whether the pro-angiogenic aspects of glioblastoma-derived exosomes could be harnessed to promote angiogenesis and healing in the context of peripheral ischemic disease. We demonstrate that the exosomes derived from glioblastoma markedly enhance endothelial cell proliferation and increase endothelial tubule formation in vitro. An analysis of the microRNA expression using next generation sequencing identified that exosomes contained a high concentration of miR-221. In addition, we found that glioblastoma exosomes contained significant amounts of the proteoglycans glypican-1 and syndecan-4, which can serve as co-receptors for angiogenic factors, including fibroblast growth factor-2 (FGF-2). In a hindlimb ischemia model in mice, we found that the exosomes promoted enhanced revascularization in comparison to control alginate gels and FGF-2 treatment alone. Taken together, our results support the fact that glioblastoma-derived exosomes have powerful effects in increasing revascularization in the context of peripheral ischemia.

Reduced MBD2 expression enhances airway inflammation in bronchial epithelium in COPD

Background

Chronic obstructive pulmonary disease (COPD) is a common inflammatory lung disease characterized by inflammatory cells activation and production of inflammatory mediators. Methyl-CpG-binding domain protein 2 (MBD2) plays an important role in diverse immunological disorders by regulating immune cell functions, such as differentiation and mediator secretion. However, the role of MBD2 in COPD remains unknown.

Methods

MBD2 protein expression in lung tissues of patients with COPD and cigarette smoke (CS)-exposed mice were evaluated by Western blot and immunohistochemistry. The role of MBD2 in cigarette smoke extract (CSE)-induction of inflammatory mediator expression in the human bronchial epithelial (HBE) cell line was assessed by silencing MBD2 expression in vitro. The involvement of signaling pathways in mediation of inflammation was tested with signaling inhibitors.

Results

Compared with controls, MBD2 expression was distinctly reduced in the bronchial epithelium of both patients with COPD and CS-exposed mice. Moreover, MBD2 expression was decreased in HBE after CSE stimulation in vitro. Moreover, MBD2 knockdown enhanced interleukin (IL)-6 and IL-8 expression in HBE in the presence and absence of CSE treatment by the ERK signaling pathway.

Conclusion

MBD2 protein expression was reduced in the airway epithelium of COPD. In HBE, this reduced expression was associated with increased levels of IL-6 and IL-8 mediated by the ERK pathway. These results suggest that MBD2 could contribute to chronic airway inflammation in COPD.

MicroRNA-205-5p suppresses the invasiveness of oral squamous cell carcinoma by inhibiting TIMP‑2 expression

MicroRNAs (miRNAs or miRs) play important roles in carcinogenesis. The miRNA, miR-205-5p, has been reported to suppress the growth of various types of tumor; however, its functional contribution to oral squamous cell carcinoma (OSCC) is not yet clear. Thus, this study was conducted to determine the miRNA expression signatures in OSCC and to investigate the functional role of miR‑205‑5p in OSCC cells. We measured miR‑205‑5p expression by RT-qPCR, and examined the function of miR‑205‑5p by transfecting a miR‑205‑5p mimic or inhibitor into OSCC cells and measuring cell proliferation, migration and invasiveness. Genes targeted by miR‑205‑5p were identified using the TargetScan database and verified by western blot analysis, luciferase reporter assay and ELISA. We found that miR‑205‑5p was significantly downregulated in OSCC cell lines and tissue specimens. Following transfection of miR‑205‑5p mimic or inhibitor into the cancer cell lines, miR‑205‑5p overexpression significantly suppressed cancer cell migration and invasion. We further demonstrated that miR‑205‑5p directly targeted and regulated the tissue inhibitor of metalloproteinases‑2 (TIMP‑2) gene. The silencing of TIMP‑2 suppressed cancer cell invasion and the activation of pro‑matrix metalloproteinase‑2 (pro‑MMP‑2). These results suggest that TIMP‑2 promotes tumor progression, and that miR‑205‑5p directly regulates TIMP‑2, thereby suppressing pro‑MMP‑2 activation and inhibiting OSCC cell invasiveness. Our data describing the pathways regulated by miR‑205‑5p provide new insight into the mechanisms responsible for OSCC development and metastasis.

miR-195-5p Suppresses the Proliferation, Migration, and Invasion of Oral Squamous Cell Carcinoma by Targeting TRIM14

MicroRNAs (miRNAs) play an essential role in tumor biological processes through interacting with specific gene targets. The involvement of miR-195-5p in cell proliferation, invasion, and migration has been demonstrated in several cancer cell lines, while its function in oral squamous cell carcinoma (OSCC) remains unclear. Here we find that miR-195-5p expression is lower in OSCC than in nontumor tissues, while its overexpression in cell lines can lead to the promotion of apoptosis and the reduction of cell growth, migration, and invasion. Moreover, we identify the tripartite motif-containing protein (TRIM14) as a target of miR-195-5p. Therefore, we reason that the tumor suppressor role of miR-195-5p in OSCC is dependent on the interaction with TRIM14.

MiR-139-5p inhibits the tumorigenesis and progression of oral squamous carcinoma cells by targeting HOXA9

Our study sought to clarify the effects of microRNA-139-5p (miR-139-5p) in the tumorigenesis and progression of oral squamous cell carcinoma (OSCC) by regulating HOXA9. MiR-139-5p and HOXA9 expression in OSCC tissues, tumour adjacent tissues, OSCC cells and normal cells were tested by qRT-PCR. SAS and CAL-27 cell lines were selected in among four OSCC cell lines and then transfected with miR-139-5p mimics, pEGFP-HOXA9 and cotransfected with miR-139-5p mimics + pEGFP-HOXA9. We used MTT, colony formation, transwell and wound healing assays to analyse cell viability, proliferation, invasion and migration. The target relationship between miR-139-5p and HOXA9 was verified by luciferase reporter assay and Western blot, respectively. MiR-139-5p was down-regulated, whereas HOXA9 was up-regulated in OSCC tissues and cells. The proliferation, invasion and migration ability of SAS and CAL-27 cells in miR-139-5p mimics group were significantly weaker than those in the control group and the miR-NC group (P < 0.01). MiR-139-5p can negatively regulate HOXA9. The proliferation, invasion and migration of SAS and CAL-27 cells in the miR-139-5p mimics + pEGFP-HOXA9 group were not significantly different from those in the blank control and negative control groups (P > 0.05). Our results indicated that miR-139-5p could directly inhibit HOXA9, which might be a potential mechanism in inhibiting the proliferation, invasiveness and migration of OSCC cells.

Oral squamous cell carcinoma cells are resistant to doxorubicin through upregulation of miR‑221

Oral squamous cell carcinoma (OSCC) cells are usually resistant to doxorubicin, resulting in limited application of doxorubicin in OSCC treatment. MicroRNA (miR)‑221 has been reported to be involved in the development of OSCC; however, it remains unclear if and how miR‑221 is implicated in modulating the sensitivity of OSCC cells to doxorubicin. In the present study, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was used to assess miR‑221 expression in OSCC cells in response to doxorubicin treatment. In addition, the SCC4 and SCC9 OSCC cell lines were transfected with anti‑miR‑221 oligonucleotides and cell viability and apoptosis following doxorubicin treatment were evaluated using an MTT assay and Annexin V‑fluorescein isothiocyanate/Hoechst double staining, respectively. The mRNA and protein expression levels of tissue inhibitor of metalloproteinase‑3 (TIMP3) in anti‑miR‑221‑transfected cells were assessed using RT‑qPCR and western blot analysis, respectively. Furthermore, a luciferase reporter assay was performed to investigate whether TIMP3 may be a direct target gene of miR‑221. To explore the roles of TIMP3 in miR‑221‑mediated cell responses, TIMP3 expression was silenced following transfection with TIMP3‑targeting small interfering (si)RNA in cells overexpressing miR‑221, and cell viability and apoptosis in response to doxorubicin treatment were measured. The results of the present study demonstrated that miR‑221 expression was upregulated in SCC4 and SCC9 cells following treatment with doxorubicin. However, inhibiting the doxorubicin‑induced upregulation of miR‑221 through transfection with anti‑miR‑221 oligonucleotides led to an increase in the sensitivity of OSCC cells to doxorubicin. In addition, the results indicated that TIMP3 was a direct target of miR‑221 in OSCC cells, as determined by a 3'‑untranslated region luciferase reporter assay. Co‑transfection of cells with anti‑miR‑221 oligonucleotides and TIMP3‑specific small interfering RNA resulted in reduced sensitivity to doxorubicin compared with the cells transfected with the miR‑221 inhibitor alone. In conclusion, these results indicated that OSCC cells are resistant to doxorubicin through upregulation of miR‑221, which in turn downregulates TIMP3. Therefore, silencing miR‑221 or upregulating TIMP3 may be considered promising therapeutic approaches to enhance the sensitivity of OSCC to doxorubicin.

MiR-520b inhibits the development of glioma by directly targeting MBD2

MicroRNAs play important roles in the process of cancer, which microRNA-520b (miR-520b) has been reported to play critical roles in tumor progression in many types of cancers. However, its role in glioma remains unknown. In this study, we found that miR-520b could inhibit growth and progression in glioma by targeting methyl-CpG-binding domain 2 (MBD2). First, we analyzed the expression of miR-520b in different glioma grades and different cell lines (U87, U251 and astrocyte). Then we assessed the effect of miR-520b on glucose metabolism, invasion, angiogenesis and chemosensitivity in U87 and U251 cells. By using an online database, miR-520b was found to directly bind to the 3'-untranslated regions (3'-UTR) of MBD2 and reduce its expression at the protein level, which further inhibits the development of glioma. MBD2 was also found to be over-expressed in human glioma tissues and in U87 and U251 cells and its level was inversely correlated with that of miR-520b. Furthermore, restoration of MBD2 partially rescued the miR-520b-induced inhibitory effect on glucose metabolism, invasion, angiogenesis and chemosensitivity in glioma cells. In summary, to date, this is the first study to demonstrate that miR-520b functions as a tumor suppressor in glioma by directly targeting MBD2, suggesting that MBD2 may be a potential therapeutic target for glioma.

Comparison of the miRNA expression profiles in fresh frozen and formalin-fixed paraffin-embedded tonsillar tumors

MicroRNAs are considered as promising prognostic and diagnostic biomarkers of human cancer since their profiles differ between tumor types. Most of the tumor profiling studies were performed on rarely available fresh frozen (FF) samples. Alternatively, archived formalin-fixed paraffin-embedded (FFPE) tissue samples are also well applicable to larger-scale retrospective miRNA profiling studies. The aim of this study was to perform systematic comparison of the miRNA expression profiles between FF and macrodissected FFPE tonsillar tumors using the TaqMan Low Density Array system, with the data processed by different software programs and two types of normalization methods. We observed a marked correlation between the miRNA expression profiles of paired FF and FFPE samples; however, only 27-38% of the differentially deregulated miRNAs overlapped between the two source systems. The comparison of the results with regard to the distinct modes of data normalization revealed an overlap in 58-67% of differentially expressed miRNAs, with no influence of the choice of software platform. Our study highlights the fact that for an accurate comparison of the miRNA expression profiles from published studies, it is important to use the same type of clinical material and to test and select the best-performing normalization method for data analysis.

Alteration of methyl-CpG binding domain family in patients with chronic hepatitis B

BACKGROUND AND OBJECTIVE

Epigenetics contributes to the outcome of chronic hepatitis B virus (HBV) infection. However, the role of methyl-CpG binding domain (MBD) family in the natural history of chronic hepatitis B (CHB) has not been demonstrated. It is aimed to investigate the dynamic expression of MBD family and assess the potential association of MBD family in the progression of CHB.

METHODS

Quantitative real-time polymerase chain reaction (RT-PCR) was used to determine the mRNA levels of MBD family in peripheral blood mononuclear cells (PBMCs) from 223 patients with CHB as training cohort, 146 patients with CHB as validation cohort [immune-tolerant (IT), immune clearance (IC), non/low-replicative (LR) and HBeAg negative hepatitis (ENH)], and 14 healthy controls (HCs).

RESULTS

The mRNA levels of MeCP2, MBD1, MBD2 and MBD4 were upregulated in patients with CHB compared with HCs. MBD1 mRNA was highest expressed in IT phase than other phases. The optimal cut-off value for MBD1 mRNA in discriminating IT phase from CHB was 0.0305 in both training and validation cohorts. Both MBD2 and MBD4 mRNA were highest expressed in IC phase than other phases. Moreover, the optimal cut-off values for MBD2 and MBD4 mRNA in discriminating IC phase from CHB were 0.0069 and 0.00099. Furthermore, MBD2 plus MBD4 performed better than MBD2 alone for discriminating IC phase from CHB in training (area under the curve of receiver operating characteristics [AUC] 0.736 vs. 0.671, P=0.0225) and validation cohorts (AUC 0.754 vs. 0.665, P=0.004). MeCP2 mRNA was highest expressed in patients with S3+S4. MeCP2 mRNA has higher AUC than APRI score for predicting S3+S4 and S4 in fibrosis.

CONCLUSIONS

MBD family is involved in the pathogenesis of CHB and is correlated with disease progression, suggesting the value in evaluating disease severity.

Icaritin induces mitochondrial apoptosis by up-regulating miR-124 in human oral squamous cell carcinoma cells

AIM OF THE STUDY

The present study is aimed to investigate the apoptosis-inducing effect of icaritin in human oral squamous cell carcinoma (OSCC) cells and the associated mechanisms.

MATERIALS AND METHODS

KB and SCC9 cell lines were used as model cell lines. Effect of icaritin on apoptosis was analyzed by flow cytometry. The effect of icaritin on mitochondrial apoptotic pathway was demonstrated by loss of mitochondrial membrane potential and release of cytocrome C from mitochondria. MiR-124 mimic and miR-124 inhibitor were used to manipulate the expression of miR-124 in OSCC cells. SiRNA targeting Sp1 and DNMT1 as well as Sp1 and DNMT1 overexpressing vector were utilized to confirm their roles in the apoptosis-inducing effect of icaritin in OSCC cells. Activation of relevant signaling pathway by icaritin and effect of icaritin on expression of targeting molecules were determined by western blots or qRT-PCR.

RESULTS

Our results showed that icaritin inhibited tumor cell viability in a dose- and time-dependent manner, and induced cell apoptosis via intrinsic mitochondrial pathway by upregulating miR-124. Moreover, our results showed that the icaritin exerted regulatory effect on miR-124 through suppressing Sp1/DNMT1 signaling.

CONCLUSION

Our data provide the first experimental evidence that icaritin induces mitochondrial apoptosis in OSCC cells by upregulating miR-124 and suggest a new mechanism to explain its anti-tumor effects.