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Background: Cancer stem cells form a rare cell population in tumors that contributes to metastasis, recurrence and chemoresistance in cancer patients. Circular RNAs (circRNAs) are post-transcriptional regulators of gene expression that sponge targeted microRNA (miRNAs) to affect a multitude of downstream cellular processes. We previously showed in an expression profiling study that circZNF800 (hsa_circ_0082096) was up-regulated in cancer stem cell-enriched spheroids derived from colorectal cancer (CRC) cell lines., Methods: Spheroids were generated in suspension spheroidal culture. The ZNF800 mRNA, pluripotency stem cell markers and circZNF800 levels were determined by quantitative RT-PCR. CircZNF800-miRNA interactions were shown in RNA pulldown assays and the miRNA levels determined by stem-loop qRT-PCR. The effects of circZNF800 on cell proliferation were tested by EdU staining followed by flowcytometry. Expression of stem cell markers CD44/CD133, Lgr5 and SOX9 was demonstrated in immunofluorescence microscopy. To manipulate the cellular levels of circZNF800, circZNF800 over-expression was achieved via transfection of in vitro synthesized and circularized circZNF800, and knockdown attained using a CRISPR-Cas13d-circZNF800 vector system. Xenografted nude mice were used to demonstrate effects of circZNF800 over-expression and knockdown on tumor growth in vivo., Results: CircZNF800 was shown to be over-expressed in late-stage tumor tissues of CRC patients. Data showed that circZNF800 impeded expression of miR-140-3p, miR-382-5p and miR-579-3p while promoted the mRNA levels of ALK/ACVR1C, FZD3 and WNT5A targeted by the miRNAs, as supported by alignments of seed sequences between the circZNF800-miRNA, and miRNA-mRNA paired interactions. Analysis in CRC cells and biopsied tissues showed that circZNF800 positively regulated the expression of intestinal stem cell, pluripotency and cancer stem cell markers, and promoted CRC cell proliferation, spheroid and colony formation in vitro, all of which are cancer stem cell properties. In xenografted mice, circZNF800 over-expression promoted tumor growth, while circZNF800 knockdown via administration of CRISPR Cas13d-circZNF800 viral particles at the CRC tumor sites impeded tumor growth., Conclusions: CircZNF800 is an oncogenic factor that regulate cancer stem cell properties to lead colorectal tumorigenesis, and may be used as a predictive marker for tumor progression and the CRISPR Cas13d-circZNF800 knockdown strategy for therapeutic intervention of colorectal cancer., (© 2023. The Author(s).)

Cell migration and invasion are modulated by epithelial-to-mesenchymal transition (EMT) and the reverse MET process. Despite the detection of microRNA-362 (miR-362, both the miR-362-5p and -3p species) in cancers, none of the identified miR-362 targets is a mesenchymal or epithelial factor to link miR-362 with EMT/MET and metastasis. Focusing on the TGF-β/SMAD signaling pathway in this work, luciferase assays and western blot data showed that miR-362 targeted and negatively regulated expression of SMAD4 and E-cadherin, but not SNAI1, which is regulated by SMAD4. However, miR-362 knockdown also down-regulated SMAD4 and SNAI1, but up-regulated E-cadherin expression. Wound-healing and transwell assays further showed that miR-362 knockdown suppressed cell migration and invasion, effects which were reversed by over-expressing SMAD4 or SNAI1, or by knocking down E-cadherin in the miR-362 knockdown cells. In orthotopic mice, miR-362 knockdown inhibited metastasis, and displayed the same SMAD4 and E-cadherin expression profiles in the tumors as in the in vitro studies. A scheme is proposed to integrate miR-362 negative regulation via SMAD4, and to explain miR-362 positive regulation of SMAD4 via miR-362 targeting of known SMAD4 suppressors, BRK and DACH1, which would have resulted in SMAD4 depletion and annulment of subsequent involvement in TGF-β signaling actions. Hence, miR-362 both negatively and positively regulates SMAD4 expression in TGF-β/SMAD signaling pathway to suppress cell motility and invasiveness and metastasis, and may explain the reported clinical association of anti-miR-362 with suppressed metastasis in various cancers. MiR-362 knockdown in miR-362-positive cancer cells may be used as a therapeutic strategy to suppress metastasis., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Spheroidal cancer cell cultures have been used to enrich cancer stem cells (CSC), which are thought to contribute to important clinical features of tumors. This study aimed to map the regulatory networks driven by circular RNAs (circRNAs) in CSC-enriched colorectal cancer (CRC) spheroid cells. The spheroid cells established from two CRC cell lines acquired stemness properties in pluripotency gene expression and multi-lineage differentiation capacity. Genome-wide sequencing identified 1503 and 636 circRNAs specific to the CRC parental and spheroid cells, respectively. In the CRC spheroids, algorithmic analyses unveiled a core network of mRNAs involved in modulating stemness-associated signaling pathways, driven by a circRNA-microRNA (miRNA)-mRNA axis. The two major circRNAs, hsa_circ_0066631 and hsa_circ_0082096, in this network were significantly up-regulated in expression levels in the spheroid cells. The two circRNAs were predicted to target and were experimentally shown to down-regulate miR-140-3p, miR-224, miR-382, miR-548c-3p and miR-579, confirming circRNA sponging of the targeted miRNAs. Furthermore, the affected miRNAs were demonstrated to inhibit degradation of six mRNA targets, viz. ACVR1C/ALK7, FZD3, IL6ST/GP130, SKIL/SNON, SMAD2 and WNT5, in the CRC spheroid cells. These mRNAs encode proteins that are reported to variously regulate the GP130/Stat, Activin/Nodal, TGF-β/SMAD or Wnt/β-catenin signaling pathways in controlling various aspects of CSC stemness. Using the CRC spheroid cell model, the novel circRNA-miRNA-mRNA axis mapped in this work forms the foundation for the elucidation of the molecular mechanisms of the complex cellular and biochemical processes that determine CSC stemness properties of cancer cells, and possibly for designing therapeutic strategies for CRC treatment by targeting CSC.

Human head and neck squamous cell carcinoma (HNSCC) is usually treated by surgical resection with adjuvant radio-chemotherapy. In this study, we examined whether the radiopharmaceutical 188Re-liposome could suppress the growth of HNSCC followed by an investigation of molecular mechanisms. The orthotopic HNSCC tumor model was established by human hypopharyngeal FaDu carcinoma cells harboring multiple reporter genes. The drug targeting and therapeutic efficacy of 188Re-liposome were examined using in vivo imaging, bio-distribution, pharmacokinetics, and dosimetry. The results showed that 188Re-liposome significantly accumulated in the tumor lesion compared to free 188Re. The circulation time and tumor targeting of 188Re-liposome were also longer than that of free 188Re in tumor-bearing mice. The tumor growth was suppressed by 188Re-liposome up to three weeks using a single dose treatment. Subsequently, microarray analysis followed by Ingenuity Pathway Analysis (IPA) showed that tumor suppressor let-7 microRNA could be an upstream regulator induced by 188Re-liposome to regulate downstream genes. Additionally, inhibition of let-7i could reduce the effects of 188Re-liposome on suppression of tumor growth, suggesting that let-7 family was involved in 188Re-liposome mediated suppression of tumor growth in vivo. Our data suggest that 188Re-liposome could be a novel strategy for targeting HNSCC partially via induction of let-7 microRNA.

Lin28, a key factor for cellular reprogramming and generation of induced pluripotent stem cell (iPSC), makes a critical contribution to tumorigenicity by suppressing Let-7. However, it is unclear whether Lin28 is involved in regulating cancer stem-like cells (CSC), including in oral squamous carcinoma cells (OSCC). In this study, we demonstrate a correlation between high levels of Lin28B, Oct4, and Sox2, and a high percentage of CD44(+)ALDH1(+) CSC in OSCC. Ectopic Lin28B expression in CD44(-)ALDH1(-)/OSCC cells was sufficient to enhance Oct4/Sox2 expression and CSC properties, whereas Let7 co-overexpression effectively reversed these phenomena. We identified ARID3B and HMGA2 as downstream effectors of Lin28B/Let7 signaling in regulating endogenous Oct4 and Sox2 expression. Let7 targeted the 3' untranslated region of ARID3B and HMGA2 and suppressed their expression, whereas ARID3B and HMGA2 increased the transcription of Oct4 and Sox2, respectively, through promoter binding. Chromatin immunoprecipitation assays revealed a direct association between ARID3B and a specific ARID3B-binding sequence in the Oct4 promoter. Notably, by modulating Oct4/Sox2 expression, the Lin28B-Let7 pathway not only regulated stemness properties in OSCC but also determined the efficiency by which normal human oral keratinocytes could be reprogrammed to iPSC. Clinically, a Lin28B(high)-Let7(low) expression pattern was highly correlated with high levels of ARID3B, HMGA2, OCT4, and SOX2 expression in OSCC specimens. Taken together, our results show how Lin28B/Let7 regulates key cancer stem-like properties in oral squamous cancers., (©2015 American Association for Cancer Research.)

Cofilin-1, a non-muscle isoform of actin regulatory protein that belongs to the actin-depolymerizing factor (ADF)/cofilin family is known to affect cancer development. Previously, we found that over-expression of cofilin-1 suppressed the growth and invasion of human non-small cell lung cancer (NSCLC) cells in vitro. In this study, we further investigated whether over-expression of cofilin-1 can suppress tumor growth in vivo, and performed a microRNA array analysis to better understand whether specific microRNA would be involved in this event. The results showed that over-expression of cofilin-1 suppressed NSCLC tumor growth using the xenograft tumor model with the non-invasive reporter gene imaging modalities. Additionally, cell motility and invasion were significantly suppressed by over-expressed cofilin-1, and down-regulation of matrix metalloproteinase (MMPs) -1 and -3 was concomitantly detected. According to the microRNA array analysis, the let-7 family, particularly let-7b and let-7e, were apparently up-regulated among 248 microRNAs that were affected after over-expression of cofilin-1 up to 7 days. Knockdown of let-7b or let-7e using chemical locked nucleic acid (LNA) could recover the growth rate and the invasion of cofilin-1 over-expressing cells. Next, the expression of c-myc, LIN28 and Twist-1 proteins known to regulate let-7 were analyzed in cofilin-1 over-expressing cells, and Twist-1 was significantly suppressed under this condition. Up-regulation of let-7 microRNA by over-expressed cofilin-1 could be eliminated by co-transfected Twist-1 cDNA. Taken together, current data suggest that let-7 microRNA would be involved in over-expression of cofilin-1 mediated tumor suppression in vitro and in vivo., (Copyright © 2015 Elsevier B.V. All rights reserved.)

MicroRNA122 (miR122), a liver-specific microRNA, plays critical roles in homeostatic regulation and hepatic-specific differentiation. Induced pluripotent stem cells (iPSCs) have promising potential in regenerative medicine, but it remains unknown whether non-viral vector-mediated miR122 delivery can enhance the differentiation of iPSCs into hepatocyte-like cells (iPSC-Heps) and rescue thioacetamide-induced acute hepatic failure (AHF) in vivo. In this study, we demonstrated that embedment of miR122 complexed with polyurethane-graft-short-branch polyethylenimine copolymer (PU-PEI) in nanostructured amphiphatic carboxymethyl-hexanoyl chitosan (CHC) led to dramatically enhanced miR122 delivery into human dental pulp-derived iPSCs (DP-iPSCs) and facilitated these DP-iPSCs to differentiate into iPSC-Heps (miR122-iPSC-Heps) with mature hepatocyte functions. Microarray and bioinformatics analysis further indicated that CHC/PU-PEI-miR122 promoted the gene-signature pattern of DP-iPSCs to shift into a liver-specific pattern. Furthermore, intrahepatic delivery of miR122-iPSC-Heps, but not miR-Scr-iPSC-Heps, improved liver functions and rescued recipient survival, and CHC-mediated delivery showed a better efficacy than that using phosphate buffered saline as a delivery vehicle. In addition, these transplanted miR122-iPSC-Heps remained viable and could produce circulatory albumin for 4 months. Taken together, our findings demonstrate that non-viral delivery of miR122 shortens the time of iPSC differentiation into hepatocytes and the delivery of miR122-iPSC-Heps using CHC as a vehicle exhibited promising hepatoprotective efficacy in vivo. miR122-iPSC-Heps may represent a feasible cell source and provide an efficient and alternative strategy for hepatic regeneration in AHF., (Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Bacterial lipopolysaccharide (LPS) is an effective trigger of the inflammatory response during infection with gram-negative bacilli (GNB), which implicates the pathogenesis of sepsis and septic shock. MicroRNAs (miRNAs) are shown to have a significant role in the fine-tuning of toll-like receptor (TLR)-mediated inflammatory response. We profiled miRNA expression levels in peripheral leukocytes of GNB urosepsis patients and compared them with those of healthy controls. We further explored the regulatory mechanism of endotoxin-responsive miRNAs in TLR and cytokine signaling by using human monocytic cell line (THP-1 cells) treated with LPS antigen stimulation. The expression of two miRNAs, that is, let-7a (P < 0.001) and miR-150 (P < 0.001), were confirmed to be significantly downregulated in GNB urosepsis patients compared with healthy controls. The expression of let-7a is first to be identified as a biomarker of GNB sepsis. By using an in vitro model with the human monocytic cell line, we demonstrated that LPS stimulation downregulated the THP-1 cell expression of let-7a. The downregulation of let-7a is correlated with the induced expression of cytokine-inducible Src homology 2-containing protein without change in cytokine-inducible Src homology 2-containing protein mRNA levels in THP-1 cells via TLR signaling pathway activation. Moreover, gain of function by overexpression of let-7a revealed that let-7a significantly decreased tumor necrosis factor-α and interleukin-1β production in response to LPS. Reduced let-7a and miR-150 levels in peripheral leukocytes correlate with GNB urosepsis patients. Furthermore, let-7a is relevant to the regulation of TLR-mediated innate immune response.

Lymph node metastasis (LNM) in gastric cancer is associated with higher rate of cancer recurrence and poor prognosis. As a result, a reliable biomarker for the prediction of LNM is important and would be valuable in the clinical practice. MiRNA microarray revealed that ten miRNAs were expressed significantly different among patients with or without LNM. A total of 46 gastric cancer patients were enrolled and divided into two groups (23 in each group) according to the presence or absence of LNM. RT-PCR of these 10 miRNAs was investigated and compared between the two groups. MiR-1207-5p was significantly upregulated in gastric cancer patients without LNM compared with those with LNM. Patients with upregulated miR-1207-5p had less scirrhous stromal reaction, less lymphovascular invasion, and earlier pathological T category, N category, and TNM stage, compared with those with downregulated or unchanged miR-1207-5p. Multivariate analysis showed that stromal reaction type, lymphovascular invasion, pathological T category and TNM stage, and expression of miR-1207-5p were independent risk factors of LNM. MiR-1207-5p could serve as a useful biomarker in the prediction of LNM in gastric cancer.

Primary central nervous system (CNS) atypical teratoid/rhabdoid tumor (ATRT) is an extremely malignant pediatric brain tumor observed in infancy and childhood. It has been reported that a subpopulation of CD133(+) cells isolated from ATRT tumors present with cancer stem-like and radioresistant properties. However, the exact biomolecular mechanisms of ATRT or CD133-positive ATRT (ATRT-CD133(+)) cells are still unclear. We have previously shown that ATRT-CD133(+) cells have pluripotent differentiation ability and the capability of malignant cells to be highly resistant to ionizing radiation (IR). By using microRNA array and quantitative RT-PCR in this study, we showed that expression of miR142-3p was lower in ATRT-CD133(+) cells than in ATRT-CD133(-) cells. miR142-3p overexpression significantly inhibited the self-renewal and tumorigenicity of ATRT-CD133(+) cells. On the contrary, silencing of endogenous miR142-3p dramatically increased the tumor-initiating and stem-like cell capacities in ATRT cells or ATRT-CD133(-) cells and further promoted the mesenchymal transitional and radioresistant properties of ATRT cells. Most importantly, therapeutic delivery of miR142-3p in ATRT cells effectively reduced its lethality by blocking tumor growth, repressing invasiveness, increasing radiosensitivity, and prolonging survival time in orthotropic-transplanted immunocompromised mice. These results demonstrate the prospect of developing novel miRNA-based strategies to block the stem-like and radioresistant properties of malignant pediatric brain cancer stem cells.

The purpose of this study was to isolate cancer stem cells (CSCs, also called tumor-initiating cells, TICs) from established human colorectal carcinoma (CRC) cell lines, characterize them extensively and dissect the mechanism for their stemness. Freshly isolated CD44(+) and CD44(-) cells from the HCT-15 human colon cancer cell line were subjected to various analyses. Interestingly, CD44(+) cells exhibited higher soft agar colony-forming ability and in vivo tumorigenicity than CD44(-) cells. In addition, the significant upregulation of the protein Snail and the downregulation of miR-203, a stemness inhibitor, in CD44(+) cells suggested that this population possessed higher invasion/metastasis and differentiation potential than CD44(-) cells. By manipulating the expression of CD44 in HCT-15 and HCT-116 cells, we found that the levels of several EMT activators and miR-203 were positively and negatively correlated with those of CD44, respectively. Further analyses revealed that miR-203 levels were repressed by Snail, which was shown to bind to specific E-box(es) present in the miR-203 promoter. In agreement, silencing miR-203 expression in wild-type HCT-116 human colon cancer cells also resulted in an increase of their stemness. Finally, we discovered that c-Src kinase activity was required for the downregulation of miR-203 in HCT-15 cells, which was stimulated by the interaction between hyaluronan (HA) and CD44. Taken together, CD44 is a critical molecule for modulating stemness in CSCs. More importantly, we show for the first time that the downregulation of miR-203 by HA/CD44 signaling is the main reason for stemness-maintenance in colon cancer cells., (© 2013.)

Epigenetic regulation plays a critical role in glioblastoma (GBM) tumorigenesis. However, how microRNAs (miRNAs) and cytokines cooperate to regulate GBM tumor progression is still unclear. Here, we show that interleukin-6 (IL-6) inhibits miR142-3p expression and promotes GBM propagation by inducing DNA methyltransferase 1-mediated hypermethylation of the miR142-3p promoter. Interestingly, miR142-3p also suppresses IL-6 secretion by targeting the 3' UTR of IL-6. In addition, miR142-3p also targets the 3' UTR and suppresses the expression of high-mobility group AT-hook 2 (HMGA2), leading to inhibition of Sox2-related stemness. We further show that HMGA2 enhances Sox2 expression by directly binding to the Sox2 promoter. Clinically, GBM patients whose tumors present upregulated IL-6, HMGA2, and Sox2 protein expressions and hypermethylated miR142-3p promoter also demonstrate poor survival outcome. Orthotopic delivery of miR142-3p blocks IL-6/HMGA2/Sox2 expression and suppresses stem-like properties in GBM-xenotransplanted mice. Collectively, we discovered an IL-6/miR142-3p feedback-loop-dependent regulation of GBM malignancy that could be a potential therapeutic target., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Purpose: MicroRNA 34a (miR-34a) is involved in regulating tissue senescence. However, the role of miR-34a in age-related cataracts is unclear. In this study, we evaluated the correlations among the severity of lens opacity, patient age, and miR-34a expression level in the lens epithelium of age-related cataracts for clarifying the role of miR-34a in the lens senescence., Methods: This study was carried as a case control study in the Department of Ophthalmology, Taipei Veterans General Hospital, Taiwan. We recorded age of each patient at the time of their cataract surgery and information regarding lens opacity according to a modified version of the Lens Opacities Classification System III. Correlations among age, lens opacity, and miR-34a expression levels were evaluated., Results: This study evaluated 110 patients with a mean age of 73.19 years (SD±10.2). Older patients had higher nuclear cataract (NC), cortical (C), and posterior subcapsular cataract (P) scores (one-way analysis of variance (ANOVA), P<0.05). miR-34a expression levels were significantly different between each age group (ANOVA post hoc Bonferroni's test, P<0.001), and there were moderate correlations between high NC, C, and P cataract scores and high miR-34a levels (Pearson correlation coefficient; R=0.606, 0.575, and 0.515, respectively)., Conclusions: The current study demonstrated positive correlations between high miR-34a levels and high lens opacity severity in NC, C, or P cataracts. These results suggest that miR-34a expression has a role in lens senescence.

ALDH1(+)CD44(+) cells are putative tumor-initiating cells (TIC) in head and neck squamous cell carcinomas (HNC). miR-145 regulates tumorigenicity in various cancers but the breadth of its mechanistic contributions and potential therapeutic applications are not completely known. Here, we report that ALDH1(+)CD44(+)-HNC cells express reduced levels of miR145. SPONGE-mediated inhibition of miR-145 (Spg-miR145) was sufficient to drive tumor-initiating characteristics in non-TICs/ALDH1(-)CD44-negative HNC cells. Mechanistic analyses identified SOX9 and ADAM17 as two novel miR145 targets relevant to this process. miR-145 expression repressed TICs in HNC in a manner associated with SOX9 interaction with the ADAM17 promoter, thereby activating ADAM17 expression. Notably, the SOX9/ADAM17 axis dominated the TIC-inducing activity of miR-145. Either miR-145 suppression or ADAM17 overexpression in non-TICs/ALDH1(-)CD44(-)-HNC cells increased expression and secretion of interleukin (IL)-6 and soluble-IL-6 receptor (sIL-6R). Conversely, conditioned medium from Spg-miR145-transfected non-TICs/ALDH1(-)CD44(-)-HNC cells was sufficient to confer tumor-initiating properties in non-TICs/ALDH1(-)CD44(-)-HNC and this effect could be abrogated by an IL-6-neutralizing antibody. We found that curcumin administration increased miR-145 promoter activity, thereby decreasing SOX9/ADAM17 expression and eliminating TICs in HNC cell populations. Delivery of lentivral-miR145 or orally administered curcumin blocked tumor progression in HNC-TICs in murine xenotransplant assays. Finally, immunohistochemical analyses of patient specimens confirmed that an miR-145(low)/SOX9(high)/ADAM17(high) phenotype correlated with poor survival. Collectively, our results show how miR-145 targets the SOX9/ADAM17 axis to regulate TIC properties in HNC, and how altering this pathway may partly explain the anticancer effects of curcumin. By inhibiting IL-6 and sIL-6R as downstream effector cytokines in this pathway, miR-145 seems to suppress a paracrine signaling pathway in the tumor microenvironment that is vital to maintain TICs in HNC., (©2013 AACR.)

Purpose: MicroRNA-145 (miR-145) has known anti-tumor properties and has been reported to be involved in regulating corneal epithelium differentiation. The exact role of miR-145 in ocular tissue remains unclear. In this study, we evaluate the effect of miR-145 expression levels on pterygium properties., Setting: Ophthalmology department of a tertiary medical center., Design: : Case series study., Methods: Information regarding patient age, pterygium recurrence and pterygium severity (extension [E], vascularity [V] and thickness [T]) were gathered from records. Expression levels of miR-145 were obtained through examination of excised pterygium tissue. Correlations between age, pterygium classification, and miR-145 levels were evaluated., Results: This study evaluated 253 patients (mean age 54.1±10.8 years). As pterygium severity increased, miR-145 levels decreased. Negative correlations were also found between miR-145 expression levels and pterygium extension (E) and vascularity (V). Thickness (T) had a weak negative correlation. There was only a mild negative correlation between patient age and miR-145 levels, which was only seen in patients with primary pterygium (not recurrent ones). Additionally, miR-145 expression was significantly higher in primary samples than in recurrent ones., Conclusions: We demonstrated an association between miR-145 and pterygium characteristics, consistent with its known tumor suppression effect. Because the management of pterygium is often difficult, we suggest that miR-145 should be further studied as a potential treatment., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Glioblastoma multiforme (GBM), the most common and aggressive primary brain tumor, is extremely resistant to current treatment paradigms and has a high rate of tumor recurrence. Recent progress in the field of tumor-initiating cells suggests that GBM stem cells (GBMSCs) may be responsible for tumor progression, resistance to treatment, and tumor relapse. Therefore, understanding the biologically significant pathways involved in modulating GBMSC-specific characteristics offers great promise for development of novel therapeutics, which may improve therapeutic efficacy and overcome present drug resistance. In addition, targeting deregulated microRNA (miRNA) has arisen as a new therapeutic strategy in treating malignant gliomas. In GBMSCs, miRNAs regulate a wide variety of tumorigenic processes including cellular proliferation, stemness maintenance, migration/invasion, apoptosis, and tumorigenicity. Nevertheless, the latest progress with GBMSCs and subsequent miRNA profiling is limited by the identification and isolation of GBMSCs. In this review, we thus summarize current markers and known features for isolation as well as the aberrant miRNAs that have been identified in GBM and GBMSCs.

Background: Let-7 microRNA is an important regulator of cellular ageing and tissue senescence. The objective of this study is to evaluate the expression of let-7a/let-7b/let-7c microRNAs in human age-related cataracts., Aim: To evaluate the correlation among the severity of lens opacity, the level of let-7a/let-7b/let-7c microRNA expression and patient age in the context of age-related cataracts., Methods: The authors evaluated the mRNA level of let-7a/let-7b/let-7c microRNA in lens epithelia obtained from 174 eyes with age-related cataracts. The authors also recorded the patient age and the severity of lens opacity as classified according to the modified version of the Lens Opacities Classification System version III., Results: Let-7b microRNA expression was demonstrated to be positively associated with patient age (R=0.472; p<0.001). A positive correlation was also observed between higher N, C and P cataract scores and higher expression of let-7b microRNA in patients with age-related cataracts (p<0.001). However, no significant correlation was observed between the let-7a and let-7c microRNA expression levels and either the severity of lens opacity or the patient age., Conclusion: These findings suggest that microRNAs play a role in age-related cataracts. A local let-7b microRNA increase may represent a risk factor in the formation of age-related cataracts.

The high invasiveness and frequent recurrence of lung adenocarcinoma (LAC) are major reasons for treatment failures and poor prognoses. Alterations in microRNAs (miRNAs) expression have been shown in lung cancers. Recent reports have demonstrated that tumors contain a small subpopulation of cancer stem cells (CSCs) that possesses self-renewing capacity and is responsible for tumor malignancy including metastasis, relapse, and chemoradioresistance. However, a miRNAs-based therapeutic approach in LAC-associated CSCs (LAC-CSCs) is still blurred. Using miRNA/mRNA-microarray and Quantitative RT-PCR, we found that the expression of miR145 is negatively correlated with the levels of Oct4/Sox2/Fascin1 in LAC patient specimens, and an Oct4(high)Sox2(high)Fascin1(high)miR145(low) phenotype predicted poor prognosis. We enriched LAC-CSCs by side population sorting or identification of CD133 markers and found that LAC-CSCs exhibited low miR145 and high Oct4/Sox2/Fascin1 expression, CSC-like properties, and chemoradioresistance. To clarify the role of miR145, we used a polyurethane-short branch-polyethylenimine (PU-PEI) as the vehicle to deliver miR145 into LAC-CSCs. PU-PEI-mediated miR145 delivery reduced CSC-like properties, and improved chemoradioresistance in LAC-CSCs by directly targeting Oct4/Sox2/Fascin1. Importantly, the repressive effect of miR145 on tumor metastasis was mediated by inhibiting the epithelial-mesenchymal transdifferentiation (EMT) and metastastic ability, partially by regulating Oct4/Sox2/Fascin1, Tcf4, and Wnt5a. Finally, in vivo study showed that PU-PEI-mediated miR145 delivery to xenograft tumors reduced tumor growth and metastasis, sensitized tumors to chemoradiotherapies, and prolonged the survival times of tumor-bearing mice. Our results demonstrated that miR145 acts as a switch regulating lung CSC-like and EMT properties, and provide insights into the clinical prospect of miR145-based therapies for malignant lung cancers., (Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.)

Glioblastomas (GBMs) are the most common primary brain tumors with poor prognosis. CD133 has been considered a putative marker of cancer stem cells (CSCs) in malignant cancers, including GBMs. MicroRNAs (miRNAs), highly conserved small RNA molecules, may target oncogenes and have potential as a therapeutic strategy against cancer. However, the role of miRNAs in GBM-associated CSCs remains mostly unclear. In this study, our miRNA/mRNA-microarray and RT-PCR analysis showed that the expression of miR145 (a tumor-suppressive miRNA) is inversely correlated with the levels of Oct4 and Sox2 in GBM-CD133(+) cells and malignant glioma specimens. We demonstrated that miR145 negatively regulates GBM tumorigenesis by targeting Oct4 and Sox2 in GBM-CD133(+). Using polyurethane-short branch polyethylenimine (PU-PEI) as a therapeutic-delivery vehicle, PU-PEI-mediated miR145 delivery to GBM-CD133(+) significantly inhibited their tumorigenic and CSC-like abilities and facilitated their differentiation into CD133(-)-non-CSCs. Furthermore, PU-PEI-miR145-treated GBM-CD133(+) effectively suppressed the expression of drug-resistance and anti-apoptotic genes and increased the sensitivity of the cells to radiation and temozolomide. Finally, the in vivo delivery of PU-PEI-miR145 alone significantly suppressed tumorigenesis with stemness, and synergistically improved the survival rate when used in combination with radiotherapy and temozolomide in orthotopic GBM-CD133(+)-transplanted immunocompromised mice. Therefore, PU-PEI-miR145 is a novel therapeutic approach for malignant brain tumors., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

MicroRNA-200c (miR200c) is emerging as an important regulator of tumourigenicity and cancer metastasis with a strong capacity for inducing epithelial-mesenchymal transitions. However, the role of miR200c in head and neck squamous cell carcinoma (HNSCC) and HNSCC-associated cancer stem cells (HNSCC-CSCs) is unknown. In this study, the expression of miR200c in the regional metastatic lymph node of HNSCC tissues was significantly decreased, but BMI1 expression was increased as compared to parental tumours. Importantly, site-directed mutagenesis with a luciferase reporter assay showed that miR200c targeted the 3' UTR of BMI1 in HNSCC cells. Isolated HNSCC-derived ALDH1(+) /CD44(+) cells displayed CSC-like tumour initiating and radio-resistant properties. The expression levels of miR200c were significantly down-regulated while BMI1 was increased in HNSCC-ALDH1(+) /CD44(+) compared to the other subsets of HNSCC cells. Furthermore, increased miR200c expression or knockdown of BMI1 could significantly inhibit the malignant CSC-like properties of ALDH1(+) /CD44(+) cells. miR200c over-expression further down-regulated the expressions of ZEB1, Snail and N-cadherin, but up-regulated E-cadherin expression in ALDH1(+) /CD44(+) cells. Finally, a xenotransplantion study confirmed that over-expression of miR200c or BMI1 knockdown effectively inhibited the lung metastatic ability and prolonged the survival rate of ALDH1(+) /CD44(+) -transplanted mice. In summary, miR200c negatively modulates the expression of BMI1 but also significantly inhibits the metastatic capability of epithelial-mesenchymal transitions in malignant HNSCC by reducing the expression of BMI1/ZEB1. Restoration of miR200c in HNSCC and CSCs may be a promising therapeutic approach., (Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Head and neck cancer (HNC) is a prevalent cancer worldwide. Let-7 has been shown to function as a tumour suppressor by regulating multiple oncogenic signalling pathways. However, the role of let-7 in head and neck cancer (HNC) and in HNC-associated tumour initiating cells (TIC) remains unclear. In this study, we first demonstrated that let-7a expression was significantly decreased but that Nanog/Oct4 expression was increased in HNC tissues as compared to adjacent normal cells. Expression of let-7a in recurrent HNC tissue and in regional metastatic lymph nodes of HNC patients was also significantly decreased, but Nanog/Oct4 expression was increased as compared to the expression levels in the parental tumours. Consistently, the stemness genes were significantly up-regulated and let-7a was down-regulated in HNC-ALDH1(+) cells relative to HNC-ALDH1(-) cells. Furthermore, lentiviral-mediated let-7a overexpression could significantly inhibit the stemness signature and the chemoresistant abilities of HNC-ALDH1(+) cells. Most importantly, overexpression of let-7 or knockdown of Nanog in ALDH1(+) cells effectively blocked tumour metastasis and significantly prolonged survival time in ALDH1(+)-transplanted immunocompromised mice. Overall, restoration of let-7a in HNC and HNC-TIC may be a new approach for the therapeutic treatment of HNC in the future. These results show that let-7a negatively modulates the expression of stemness genes and plays a role as a tumour suppressor in HNC by eliminating the putative HNC-TIC population., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

miRNAs are a group of noncoding small RNA that are capable of modulating the expression of hundreds of genes via a near-perfect or partial complementary to target mRNA. The ability to regulate multiple targets simultaneously makes miRNA a crucial regulator in many physiological conditions, especially in the aging network and process. The tremendous capability of miRNA supports its ability in regulating ageing, which is a complex process involving multiple interconnected signaling pathways. Even though the relationship between miRNA and ageing is not fully understood, studies have provided evidence showing that miRNAs participate in regulating cell cycle progression, proliferation, stemness gene expression, and stress-induced responses. Molecular studies of ageing and miRNAs would provide a more comprehensive understanding of the mechanisms of ageing and, subsequently, help to ameliorate this universal process compromising our quality of life. In this review article, we focus our attention on miRNA targets in conserved pathways involved in organism aging and aging networks, as well as cellular senescence., (Copyright © 2010 Elsevier B.V. All rights reserved.)

MicroRNAs (miRNA) are endogenously expressed noncoding RNAs with important biological and pathological functions that are yet to be fully defined. This study investigated alterations in miRNA expression in head and neck squamous cell carcinoma (HNSCC), the incidence of which is rising throughout the world. Initial screening and subsequent analysis identified a panel of aberrantly expressed miRNAs in HNSCC tissues, with miR-31 among the most markedly upregulated. Ectopic expression of miR-31 increased the oncogenic potential of HNSCC cells under normoxic conditions in cell culture or tumor xenografts. Conversely, blocking miR-31 expression reduced the growth of tumor xenografts. The in silico analysis suggested that miR-31 may target the 3' untranslated region (UTR) of factor-inhibiting hypoxia-inducible factor (FIH), a hypoxia-inducible factor (HIF) regulatory factor that inhibits the ability of HIF to act as a transcriptional regulator under normoxic conditions. In support of this likelihood, miR-31 expression repressed FIH expression and mutations within the predictive miR-31 target site in the FIH 3' UTR abrogated FIH repression. Furthermore, miR-31 expression increased HIF transactivation activity. We found that FIH suppressed oncogenic phenotypes under normoxic conditions and that this activity was abrogated by functional mutations. Lastly, increased miR-31 expression was correlated with decreased levels of FIH in tumor tissues. Our findings suggest that miR-31 contributes to the development of HNSCC by impeding FIH to activate HIF under normoxic conditions.