Genetic and epigenetic alterations of microRNAs and implications for human cancers and other diseases

MicroRNAs (miRNAs) are a well-studied group of noncoding RNAs that control gene expression by interacting mainly with messenger RNA. It is known that miRNAs and their biogenesis regulatory machineries have crucial roles in multiple cell processes; thus, alterations in these genes often lead to disease, such as cancer. Disruption of these genes can occur through epigenetic and genetic alterations, resulting in aberrant expression of miRNAs and subsequently of their target genes. This review focuses on the disruption of miRNAs and their key regulatory machineries by genetic alterations, with emphasis on mutations and epigenetic changes in cancer and other diseases.

Lumbar interbody fusion: techniques, indications and comparison of interbody fusion options including PLIF, TLIF, MI-TLIF, OLIF/ATP, LLIF and ALIF

Degenerative disc and facet joint disease of the lumbar spine is common in the ageing population, and is one of the most frequent causes of disability. Lumbar spondylosis may result in mechanical back pain, radicular and claudicant symptoms, reduced mobility and poor quality of life. Surgical interbody fusion of degenerative levels is an effective treatment option to stabilize the painful motion segment, and may provide indirect decompression of the neural elements, restore lordosis and correct deformity. The surgical options for interbody fusion of the lumbar spine include: posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), minimally invasive transforaminal lumbar interbody fusion (MI-TLIF), oblique lumbar interbody fusion/anterior to psoas (OLIF/ATP), lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF). The indications may include: discogenic/facetogenic low back pain, neurogenic claudication, radiculopathy due to foraminal stenosis, lumbar degenerative spinal deformity including symptomatic spondylolisthesis and degenerative scoliosis. In general, traditional posterior approaches are frequently used with acceptable fusion rates and low complication rates, however they are limited by thecal sac and nerve root retraction, along with iatrogenic injury to the paraspinal musculature and disruption of the posterior tension band. Minimally invasive (MIS) posterior approaches have evolved in an attempt to reduce approach related complications. Anterior approaches avoid the spinal canal, cauda equina and nerve roots, however have issues with approach related abdominal and vascular complications. In addition, lateral and OLIF techniques have potential risks to the lumbar plexus and psoas muscle. The present study aims firstly to comprehensively review the available literature and evidence for different lumbar interbody fusion (LIF) techniques. Secondly, we propose a set of recommendations and guidelines for the indications for interbody fusion options. Thirdly, this article provides a description of each approach, and illustrates the potential benefits and disadvantages of each technique with reference to indication and spine level performed.

Long-Term Outcomes of Cervical Laminoplasty in the Elderly

Incidences of cervical laminoplasty in the elderly are increasing; the influence of other age-related complications and neurological status must be considered for justifying surgery. This study identified the aforementioned influence on long-term outcomes of cervical laminoplasty in patients aged ≥75 years. Thirty-seven of 38 consecutive patients aged ≥75 years who underwent cervical laminoplasty were retrospectively evaluated. Minimum 5-year follow-up was acceptable if patients were complication-free. Follow-up was terminated when neurological evaluation was not possible, owing to death or other serious complications affecting activities of daily living (ADL). Postoperative neurological changes and newly developed severe complications were investigated. Postoperatively, one patient died of acute pneumonia, one remained nonambulatory owing to cerebral infarction, and 35 were ambulatory and were discharged. At a mean follow-up of 78 months, three patients died and nine developed serious complications severely affecting ADL. Of the 25 remaining patients, 23 remained ambulatory at mean follow-up of 105 months. Cox proportional hazard analysis revealed that postoperative motor upper and lower extremities JOA scores of ≤2 and ≤1, respectively, were risk factors for mortality or other severe complications. Postoperative neurological status can be maintained in the elderly if they remain complication-free. Poorer neurological status significantly affected their ADL and mortality.

The efficacy of pedicle screw instrument in treatment of irreducible atlantoaxial dislocation

OBJECTIVE

To explore the effect of pedicle screw instrument in treatment of irreducible atlantoaxial dislocation.

PATIENTS AND METHOD

From June 2003 to February 2009, 14 cases of atlas dislocation with upper cervical cord compression were enrolled and anterior transoral soft tissue release combined with posterior reduction and pedicle screw fixation were performed. CT, MRI and radiograph were used preoperatively, and screw placement and bone graft were administered in all cases intraoperatively. Cervical collars were used for 3 months.

RESULTS

Screws were successfully placed in atlas in all cases. The average follow-up period was 18 months. Bone fusion was observed in all cases without the following complications: neurologic symptoms, internal fixation failure and redislocation. Neurological recovery was observed in all 14 cases.

CONCLUSIONS

Pedicle screw instrument has the following advantages in atlas and axis injury treatment: direct screw placement, short-segment fusion, intraoperative reduction and high fusion rate, which should be a better surgical method for the treatment of atlantoaxial dislocation.

MicroRNAs in the pathobiology of sarcomas

Sarcomas are a rare and heterogeneous group of tumors. The last decade has witnessed extensive efforts to understand the pathobiology of many aggressive sarcoma types. In parallel, we have also begun to unravel the complex gene regulation processes mediated by microRNAs (miRNAs) in sarcomas and other cancers, discovering that microRNAs have critical roles in the majority of both oncogenic and tumor suppressor signaling networks. Expression profiles and a greater understanding of the biologic roles of microRNAs and other noncoding RNAs have considerably expanded our current knowledge and provided key pathobiological insights into many sarcomas, and helped identify novel therapeutic targets. The limited number of sarcoma patients in each sarcoma type and their heterogeneity pose distinct challenges in translating this knowledge into the clinic. It will be critical to prioritize these novel targets and choose those that have a broad applicability. A small group of microRNAs have conserved roles across many types of sarcomas and other cancers. Therapies that target these key microRNA-gene signaling and regulatory networks, in combination with standard of care treatment, may be the pivotal component in significantly improving treatment outcomes in patients with sarcoma or other cancers.

What Do We Know about the Role of miRNAs in Pediatric Sarcoma?

Non-coding RNAs have received a lot of attention in recent years, with especial focus on microRNAs (miRNAs), so much so that in the just over two decades since the first miRNA, Lin4, was described, almost 40,000 publications about miRNAs have been generated. Less than 500 of these focus on sarcoma, and only a fraction of those on sarcomas of childhood specifically, with some of these representing observational studies and others containing functionally validated data. This is a group of cancers for which prognosis is often poor and therapeutic options limited, and it is especially in these areas that strides in understanding the role of non-coding RNAs and miRNAs in particular are to be welcomed. This review deals with the main forms of pediatric sarcoma, exploring what is known about the diagnostic and prognostic profiles of miRNAs in these tumours and where novel therapeutic options might present themselves for further exploration.

Let7a involves in neural stem cell differentiation relating with TLX level

Neural stem cells (NSCs) have the potential for differentiation into neurons known as a groundbreaking therapeutic solution for central nervous system (CNS) diseases. To resolve the therapeutic efficiency of NSCs, recent researchers have focused on the study on microRNA's role in CNS. Some micro RNAs have been reported significant functions in NSC self-renewal and differentiation through the post-transcriptional regulation of neurogenesis genes. MicroRNA-Let7a (Let7a) has known as the regulator of diverse cellular mechanisms including cell differentiation and proliferation. In present study, we investigated whether Let7a regulates NSC differentiation by targeting the nuclear receptor TLX, which is an essential regulator of NSC self-renewal, proliferation and differentiation. We performed the following experiments: western blot analysis, TaqMan assay, RT-PCR, and immunocytochemistry to confirm the alteration of NSCs. Our data showed that let7a play important roles in controlling NSC fate determination. Thus, manipulating Let-7A and TLX could be a novel strategy to enhance the efficiency of NSC's neuronal differentiation for CNS disorders.

Overexpression of miR‑199b‑5p inhibits Ewing's sarcoma cell lines by targeting CCNL1

MicroRNAs (miRNAs) are known to regulate the expression of a variety of genes, which are important in the development of several types of tumor, including Ewing's sarcoma (ES), at the post‑transcriptional level. Although previous studies have identified that the expression of miRNA‑199b‑5p was downregulated in various types of tumor, the expression levels of miR‑199b‑5p in ES cells remain to be elucidated. The mechanism underlying ES via the miRNA pathway remains to be elucidated. The present study demonstrated that miR‑199b‑5p was an important regulator in ES cells and its expression was downregulated in ES originated A673/TC252 cells. The ES cell lines, A673 and TC252, were transfected with an miR‑199b‑5p mimic to overexpress the levels of this miRNA. This forced expression of miR‑199b‑5p suppressed the cell proliferation and invasion, arrested cell cycle progression, and promoted cell apoptosis. Furthermore, CCNL1 was identified by bioinformatic software as a potential target gene of miR‑199b‑5p. Following this, the present study identified CCNL1 as a direct target of miR‑199b‑5p in ES cells. Taken together, the present study established a functional link between ES, miR‑199b‑5p and CCNL1, and suggested that miR‑199b‑5p acts as a tumor suppressor and may be of diagnostic and therapeutic importance for human ES.

ASK1 modulates the expression of microRNA Let7A in microglia under high glucose in vitro condition

Hyperglycemia results in oxidative stress and leads to neuronal apoptosis in the brain. Diabetes studies show that microglia participate in the progression of neuropathogenesis through their involvement in inflammation in vivo and in vitro. In high-glucose-induced inflammation, apoptosis signal regulating kinase 1 (ASK1) triggers the release of apoptosis cytokines and apoptotic gene expression. MicroRNA-Let7A (miR-Let7A) is reported to be a regulator of inflammation. In the present study, we investigated whether miR-Let7A regulates the function of microglia by controlling ASK1 in response to high-glucose-induced oxidative stress. We performed reverse transcription (RT) polymerase chain reaction, Taqman assay, real-time polymerase chain reaction, and immunocytochemistry to confirm the alteration of microglia function. Our results show that miR-Let7A is associated with the activation of ASK1 and the expression of anti-inflammatory cytokine (interleukin (IL)-10) and Mycs (c-Myc and N-Myc). Thus, the relationship between Let-7A and ASK1 could be a novel target for enhancing the beneficial function of microglia in central nervous system (CNS) disorders.

Expression of cdk6 in head and neck squamous cell carcinoma

OBJECTIVE

Cdk6 is a key regulator during the G1/S cell cycle transition. Aberrant expression of cdk6 protein has been observed in many cancer types. However, little is known about the expression of cdk6 in head and neck squamous cell carcinoma (HNSCC) and its clinical significance. This study evaluated the expression of cdk6 in HNSCC and analyzed the relationship between cdk6 expression and clinicopathological parameters of HNSCC.

MATERIALS AND METHODS

Expression of cdk6 was immunohistochemically investigated in 98 HNSCCs. Nuclear and cytoplasmic positive cells were counted separately. Data were presented as the percentage of positive cells. The correlation between the percentage of positive cells and clinicopathological factors was determined.

RESULTS

Nuclear and cytoplasmic staining for cdk6 were detected in 91 cases and 97 cases, respectively. A significant correlation was found only between the percentage of nuclear positive cells and T classification (p value = 0.0410). Tumors with high nuclear cdk6-positive cells showed a linear trend toward advanced tumor status (p value = 0.0064).

CONCLUSIONS

Cdk6 was highly expressed in HNSCC. Tumors with high nuclear cdk6 expression tended to have advanced tumor status. These results suggest that cdk6 plays a vital role in HNSCC and is involved in tumor progression of this cancer.

CLINICAL RELEVANCE

An increased nuclear cdk6 expression is an unfavorable factor for HNSCC. Cdk6 may serve as a therapeutic target in this cancer.

DNA/RNA chimera templates improve the emission intensity and target the accessibility of silver nanocluster-based sensors for human microRNA detection

In recent years microRNAs (miRNAs) have been established as important biomarkers in a variety of diseases including cancer, diabetes, cardiovascular disease, aging, Alzheimer's disease, asthma, autoimmune disease and liver diseases. As a consequence, a variety of monitoring methods for miRNAs have been developed, including a fast and simple method for miRNA detection by exploitation of the unique photoluminescence of DNA-templated silver nanoclusters (DNA/AgNCs). To increase the versatility of the AgNC-based method, we have adopted DNA/RNA chimera templates for AgNC-based probes, allowing response from several human miRNAs which are hardly detectable with DNA-based probes. Here, we demonstrate in detail the power of DNA/RNA chimera/AgNC probes in detecting two human miRNAs, let-7a and miR-200c. The DNA/RNA chimera-based probes are highly efficient to determine the level of miRNAs in several human cell lines.

miR-211 suppresses epithelial ovarian cancer proliferation and cell-cycle progression by targeting Cyclin D1 and CDK6

BACKGROUND

Epithelial ovarian cancer (EOC) is a significant cause of morbidity and mortality. MicroRNAs play important roles in cancer development and progression. The microRNA miR-211 is localized on intron 6 of the Trpm1 gene at 15q13-q14, a locus that is frequently lost in neoplasms. Its function and loss-of-function have been described in normal and cancer cells and tissues. miR-211 is known to be dysregulated in ovarian cancer: however, its function and the downstream effect of its loss-of-function in ovarian cancer have not been described before.

METHODS

We analyzed miR-211 expression in clinical samples of primary EOC tissues compared to normal epithelial ovarian tissues and in the EOC cell lines: OVCAR3, Caov3, OVCA429, SKOV3 and A2780 compared to human ovarian surface epithelial cells. We then investigated the effect of miR-211 on EOC cell proliferation and apoptosis by counting cell numbers, MTT, colony formation, cell cycle, and PI/Annexin V staining assays. A luciferase reporter system was developed to assess miR-211 regulation of the predicted targets. Expression level of discovered targets and correlation with miR-211 expression were analyzed in EOC tissues. Finally, OVCAR3 stably expressing miR-211 or control cells were injected subcutaneously into mice to determine in vivo effect of miR-211 on tumorigenesis.

RESULTS

We found that the expression of miR-211 is downregulated in EOC tissues and cell lines compared to normal epithelial ovarian tissue and human ovarian surface epithelial cells, respectively. miR-211 was found to arrest cells in the G0/G1-phase, inhibit proliferation and induce apoptosis. Cyclin D1 and CDK6 were found to be direct targets of miR-211, and when overexpressed in miR-211-expressing EOC cells, could restore proliferative ability. Finally, in vitro investigation confirmed that miR-211 is a tumor suppressor that controls Cyclin D1 and CDK6 expression.

CONCLUSIONS

Our results demonstrate that miR-211 is a tumor suppressor that controls expression of Cyclin D1 and CDK6, and that its downregulation results in overexpression of Cyclin D1 and CDK6 which increases proliferation ability of EOC cells to proliferate compared to normal cells.

Radiological assessment of shoulder balance following posterior spinal fusion for thoracic adolescent idiopathic scoliosis

Background

The objective of this study was to evaluate shoulder balance following posterior spinal fusion for thoracic adolescent idiopathic scoliosis (AIS).

Methods

Twenty-four patients (22 females) with thoracic AIS who had undergone posterior fusion with segmental pedicle screws were retrospectively reviewed. The mean follow-up duration was 29 (range, 24–55) months. Fifteen patients had type 1 curves, seven had type 2 curves, and two had type 3 curves according to the Lenke classification. The proximal thoracic (PT) and main thoracic (MT) Cobb angles, percent correction of PT (PTC) and MT (MTC) curves, T1 tilt, and shoulder asymmetry according to radiographic shoulder height (RSH) were measured on preoperative, immediately postoperative, and final follow-up radiographs. The preoperative PT and MT curve side-bending percent correction (PTBC and MTBC) were also measured. The PTC:MTC ratio was employed as an index of PTC and MTC matching. Patients were divided into two groups according to radiographic findings immediately postoperatively: the balanced group (|RSH| <20 mm) and imbalanced group (|RSH| ≥20 mm). The preoperative indices (RSH, PTBC, MTBC, PTC, and MTC), preoperative and postoperative T1 tilt, and PTC:MTC ratio were compared between the two groups.

Results

The mean PT and MT were 33.0° and 64.2° preoperatively, 16.1° (50.5%) and 16.8° (74.0%) immediately postoperatively, and 16.9° (49.0%) and 19.2° (70.3%) at final follow-up, respectively. The mean preoperative RSH of −12.3 mm changed to +11.1 mm immediately postoperatively and improved to +5.7 mm at final follow-up. Seventeen patients were “balanced” and seven were “imbalanced” immediately postoperatively. There were significant differences in the PTC (p=0.04), postoperative T1 tilt (p=0.04), and PTC:MTC ratio (p=0.02) between the two groups (Wilcoxon rank-sum test). Only one patient had an imbalanced shoulder at the final follow-up. She had marked shoulder imbalance immediately postoperatively (RSH: +40 mm).

Conclusions

Sufficient correction of PT curves that is matched with correction of MT curves is necessary to prevent postoperative shoulder imbalance. Almost all patients in our series had satisfactory results in terms of shoulder balance at final follow-up, but one patient with marked shoulder imbalance immediately postoperatively may have residual long-term shoulder imbalance.

Identification of novel exonic mobile element insertions in epithelial ovarian cancers

Mobile elements comprise about half of the human genome. Three active mobile element families (L1, Alu, and SVA) possibly cause diseases such as cancer. We conducted mobile element insertion (MEI) profiling of 44 epithelial ovarian cancers using exome-sequencing data. We identified a total of 106 MEIs using the Mobster program, 8 of which were novel exonic MEIs.

MicroRNA expression and its clinical implications in Ewing's sarcoma

Ewing's sarcoma (EWS) is the second most common primary bone cancer, and is a predominant childhood malignant disease. Due to limited understanding of its pathogenesis and frequent occurrence of resistance to conventional types of treatment, its management remains difficult, and mortality is frequent. Development of EWS is a multistep process involving genetic and epigenetic alterations of protein-coding proto-oncogenes and tumour-suppressor genes. MicroRNAs (miRNAs) have recently been discovered as a new category of non-protein coding; small RNA molecules that regulate gene expression at the post-transcriptional level. Substantial numbers of deregulated miRNAs have been documented in EWS and their biological significance has been confirmed in multiple functional experiments. Several studies have confirmed involvement of miRNAs in various steps of EWS pathogenesis, from occurrence to metastasis. Functionally, miRNA dysregulation may promote cell-cycle progression, confer resistance to apoptosis, and enhance invasiveness and metastasis. These miRNAs have opened a novel field in cancer research with potential clinical utilization for screening, diagnosis, prognostics and prediction of response to treatment. Elucidating biological aspects of miRNA dysregulation may help better understand pathogenesis of EWS and promote development of miRNA directed-therapeutics against it.

MicroRNA-320c inhibits tumorous behaviors of bladder cancer by targeting Cyclin-dependent kinase 6

BACKGROUND

Increasing evidence has suggested that dysregulation of microRNAs (miRNAs) could contribute to human disease including cancer. Previous miRNA microarray analysis illustrated that miR-320c is down-regulated in various cancers. However, the roles of miR-320c in human bladder cancer have not been well elucidated. Therefore, this study was performed to investigate the biological functions and molecular mechanisms of miR-320c in human bladder cancer cell lines, discussing whether it could be a therapeutic biomarker of bladder cancer in the future.

METHODS

Two human bladder cancer cell lines and samples from thirteen patients with bladder cancer were analyzed for the expression of miR-320c by quantitative RT-PCR. Over-expression of miR-320c was established by transfecting mimics into T24 and UM-UC-3. Cell proliferation and cell cycle were assessed by cell viability assay, flow cytometry and colony formation assay. Cell motility ability was evaluated by transwell assay. The target gene of miR-320c was determined by luciferase assay, quantitative RT-PCR and western blot. The regulation of cell cycle and mobility by miR-320c was analyzed by western blot.

RESULTS

We observed that miR-320c was down-regulated in human bladder cancer tissues and bladder cancer cell lines T24 and UM-UC-3. Over-expression of miR-320c could induce G1 phase arrest in UM-UC-3 and T24 cells, and subsequently inhibited cell growth. We also indentified miR-320c could impair UM-UC-3 and T24 cell motility. In addition, we identified CDK6, a cell cycle regulator, as a novel target of miR-320c. Moreover, we demonstrated miR-320c could induce bladder cancer cell cycle arrest and mobility via regulating CDK6. We also observed that inhibition of miR-320c or restoration of CDK6 in miR-320c-over-expressed bladder cancer cells partly reversed the suppressive effects of miR-320c.

CONCLUSIONS

miR-320c could inhibit the proliferation, migration and invasion of bladder cancer cells via regulating CDK6. Our study revealed that miR-320c could be a therapeutic biomarker of bladder cancer in the future.

Chemical engineering approach to regenerative medicine

The intrinsically multi-factorial pathological trend of spinal cord injury is probably the most important reason behind the absence of efficient therapeutic strategies. Therefore, recent studies suggest the use of new tools combining the delivery of both cells and drugs. Systems which are able to perform multiple controlled delivery of different therapeutic agents have gained particularly strong interest. Hence, in order to avoid trial and error approaches, several studies were performed following the classic chemical engineering multiscale approach: tuning microchemistry to manipulate macro properties in order to satisfy specific medical needs as injectability, low stress on target tissues, ability to retain liquids, capability of carrying living cells, and possibility to control the delivery of drugs. In this framework we focused on injectable agarose-carbomer based hydrogels applying he results of our studies performed in the past two years: in vitro biocompatibility, physical chemical studies, drug delivery transport phenomena investigation, and in vivo biocompatibility in uninjured Brainbow mice.

Methylprednisolone release from agar-Carbomer-based hydrogel: a promising tool for local drug delivery

A number of studies and works in drug delivery literature are focused on the understanding and modelling of transport phenomena, the pivotal point of a good scaffold design for tissue engineering. Accurate knowledge of the diffusion coefficient of an active drug plays a key role in the analysis, prediction of their kinetics and formulation of efficient drug delivery systems. In this work, the kinetics of the release of methylprednisolone from agar-Carbomer hydrogel were studied taking into consideration the different drug concentrations and clearances typically achieved in in vitro or in vivo tests. Starting from the experiments it is possible to model the transport phenomenon and to calculate the diffusion coefficient through the hydrogel matrix.