In silico functional analyses and discovery of survival-associated microRNA signatures in pediatric osteosarcoma

Signal Pathways and microRNAs in Osteosarcoma Growth and the Dual Role of Mesenchymal Stem Cells in Oncogenesis

The major challenges in Osteosarcoma (OS) therapy are its heterogeneity and drug resistance. The development of new therapeutic approaches to overcome the major growth mechanisms of OS is urgently needed. The search for specific molecular targets and promising innovative approaches in OS therapy, including drug delivery methods, is an urgent problem. Modern regenerative medicine focuses on harnessing the potential of mesenchymal stem cells (MSCs) because they have low immunogenicity. MSCs are important cells that have received considerable attention in cancer research. Currently, new cell-based methods for using MSCs in medicine are being actively investigated and tested, especially as carriers for chemotherapeutics, nanoparticles, and photosensitizers. However, despite the inexhaustible regenerative potential and known anticancer properties of MSCs, they may trigger the development and progression of bone tumors. A better understanding of the complex cellular and molecular mechanisms of OS pathogenesis is essential to identify novel molecular effectors involved in oncogenesis. The current review focuses on signaling pathways and miRNAs involved in the development of OS and describes the role of MSCs in oncogenesis and their potential for antitumor cell-based therapy.

Construction and Validation of a Potent Epigenetic Modification-Related Prognostic Signature for Osteosarcoma Patients

Background

Increasing evidence has shown that tumorigenesis correlates with aberrant epigenetic factors, such as DNA methylation, histone modification, RNA m6A modification, RNA binding proteins, and transcription factors. However, it is unclear that how epigenetic genes linked with alteration contribute to osteosarcoma's incidence and clinical prognosis. We developed an epigenetic modification-related prognostic model that may improve the diagnosis and prognosis of osteosarcoma.

Methods

We investigated the epigenetic modification-associated genes and their clinical significance in osteosarcoma in this research. Our gene transcriptome data were obtained from the TARGET database and the GEO database. Bioinformatics techniques were used to investigate their functionalities. The diagnostic and prognostic models were constructed using univariate and multivariate Cox regression. In addition, we developed a nomogram indicating the practicability of the prognostic model described above.

Results

A risk score model constructed based on four epigenetic modification-related genes (MYC, TERT, EIF4E3, and RBM34) can effectively predict the prognosis of patients with osteosarcoma. Based on the risk score and clinical features, we constructed a nomogram.

Conclusion

Epigenetic modification-related genes have been identified as important prognostic markers that may assist in osteosarcoma therapy therapeutic decision-making.

Tanshinone IIA Inhibits Osteosarcoma Growth through a Src Kinase-Dependent Mechanism

Introduction

Osteosarcoma is a malignant tumor associated with high mortality rates due to the toxic side effects of current therapeutic methods. Tanshinone IIA can inhibit cell proliferation and promote apoptosis in vitro, but the exact mechanism is still unknown. The aims of this study are to explore the antiosteosarcoma effect of tanshinone IIA via Src kinase and demonstrate the mechanism of this effect.

Materials and Methods

Osteosarcoma MG-63 and U2-OS cell lines were stable transfections with Src-shRNA. Then, the antiosteosarcoma effect of tanshinone IIA was tested in vitro. The protein expression levels of Src, p-Src, p-ERK1/2, and p-AKt were detected by Western blot and RT-PCR. CCK-8 assay and BrdU immunofluorescence assay were used to detect cell proliferation. Transwell assay, cell scratch assay, and flow cytometry were used to detect cell invasion, migration, and cell cycle. Tumor-bearing nude mice with osteosarcoma were constructed. The effect of tanshinone IIA was detected by tumor HE staining, tumor inhibition rate, incidence of lung metastasis, and X-ray.

Results

The oncogene role of Src kinase in osteosarcoma is reflected in promoting cell proliferation, invasion, and migration and in inhibiting apoptosis. However, Src has different effects on cell proliferation, apoptosis, and cell cycle regulation among cell lines. At a cellular level, the antiosteosarcoma effect of tanshinone IIA is mediated by Src downstream of the MAPK/ERK and PI3K/AKt signaling pathways. At the animal level, tanshinone IIA played a role in resisting osteosarcoma formation by Src downstream of the MAPK/ERK and PI3K/AKt signaling pathways.

Conclusion

Tanshinone IIA plays an antiosteosarcoma role in vitro and in vivo and inhibits the progression of osteosarcoma mediated by Src downstream of the MAPK/ERK and PI3K/AKt signaling pathways.

Novel biomarkers for the diagnosis and prognosis of gallbladder cancer

Gallbladder cancer (GBC) is the most common form of biliary tract malignancy with a dismal prognosis. A poor outcome in patients with GBC is related to the aggressive nature of the tumor, delayed diagnosis, and a lack of reliable biomarkers and effective treatment. Therefore, early diagnosis and accurate disease assessment are crucial to prolonging the patient survival. Identification of novel prognostic and diagnostic biomarkers may help improve the early diagnostic rate and develop specific targeted treatments for patients with GBC. We herein review the novel biomarkers that may be associated with the diagnosis and prognosis in GBC and their potential clinical significance in the management of GBC.

Development of a novel immune-related genes prognostic signature for osteosarcoma

Immune-related genes (IRGs) are responsible for osteosarcoma (OS) initiation and development. We aimed to develop an optimal IRGs-based signature to assess of OS prognosis. Sample gene expression profiles and clinical information were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Genotype-Tissue Expression (GTEx) databases. IRGs were obtained from the ImmPort database. R software was used to screen differentially expressed IRGs (DEIRGs) and functional correlation analysis. DEIRGs were analyzed by univariate Cox regression and iterative LASSO Cox regression analysis to develop an optimal prognostic signature, and the signature was further verified by independent cohort (GSE39055) and clinical correlation analysis. The analyses yielded 604 DEIRGs and 10 hub IRGs. A prognostic signature consisting of 13 IRGs was constructed, which strikingly correlated with OS overall survival and distant metastasis (p < 0.05, p < 0.01), and clinical subgroup showed that the signature's prognostic ability was independent of clinicopathological factors. Univariate and multivariate Cox regression analyses also supported its prognostic value. In conclusion, we developed an IRGs signature that is a prognostic indicator in OS patients, and the signature might serve as potential prognostic indicator to identify outcome of OS and facilitate personalized management of the high-risk patients.

miR-541 serves as a prognostic biomarker of osteosarcoma and its regulatory effect on tumor cell proliferation, migration and invasion by targeting TGIF2

Background

Several studies reported the dysregulation of miR-541 in the progression of some human malignancies. Osteosarcoma (OS) is one of the most common primary malignant bone tumors. This study aimed to assess the expression and clinical significance of miR-541 in OS patients and explore the biological function of miR-541 in tumor progression.

Methods

Expression of miR-541 was detected by quantitative real-time PCR, and its prognostic value was evaluated using Kaplan-Meier survival analysis. The biological function of miR-541 was examined by analyzing its effects on OS cell proliferation, migration and invasion. Additionally, the underlying potential target of miR-541 was predicated and analyzed.

Results

The expression of miR-541 was significantly decreased in OS tissues and cell lines. The deregulated expression of miR-541 in tumor tissues was associated with the overall survival of OS patients and was a potential independent prognostic indicator. In OS cells, the overexpression of miR-541 could inhibit cell proliferation, migration and invasion. The luciferase activity results indicated that TGIF2 was a potential target of miR-541.

Conclusion

The results of this study revealed that the decreased miR-541 expression in OS patients may serve as a prognostic biomarker, and that the overexpression of miR-541 in OS cells results in inhibited cell proliferation, migration and invasion, indicating the potential of miR-541 as a therapeutic target in OS treatment.

Assessment of PDGFRβ promoter methylation in canine osteosarcoma using methylation-sensitive high-resolution melting analysis

Platelet-derived growth factor signalling pathways play a fundamental role in inducing and sustaining the proliferative and prosurvival stimuli in canine osteosarcomas (cOSAs). The increased expression of platelet-derived growth factor receptors (PDGFRs) α and β, and their cognate ligands, were almost invariably observed in cOSAs and OSA-derived cell lines. In particular, overexpression of PDGFRβ-mediated signalling pathways was found in both the tumour microenvironment, where it drives stromal cell recruitment, and in neoangiogenesis, such as in tumour cells where it triggers aberrant proliferation, migration and local invasion. The majority of the pathological consequences of PDGFRβ signalling are because of aberrant expression. In fact, epigenetic dysregulation of oncogenes throughout demethylation of their promoter has emerged as a pivotal mechanism driving oncogenesis. The aim of this study was to assess the methylation status of the PDGFRβ promoter and to clarify its role in modulating the expression of the tyrosine kinase receptor in canine osteosarcoma. The CpG island of the PDGFRβ promoter was identified using a mixed in silico and experimental approach, and a method based upon the methylation-sensitive high-resolution melting assay for quantitatively and precisely assessing the methylation status of the promoter was then set up. The method herein described was then exploited to assess the methylation status of the promoter in a case series of cOSAa. COSAs consistently but variably expressed PDGFRβ. However, the promoter was almost completely demethylated, and its methylation status did not correlate with the expression levels. This finding supported the hypothesis that post-transcriptional regulatory mechanisms may act in cOSAs.

Delineation of hypoxia-induced proteome shifts in osteosarcoma cells with different metastatic propensities

Osteosarcoma (OS) is the most common bone cancer in children and young adults. Solid tumors are characterized by intratumoral hypoxia, and hypoxic cells are associated with the transformation to aggressive phenotype and metastasis. The proteome needed to support an aggressive osteosarcoma cell phenotype remains largely undefined. To link metastatic propensity to a hypoxia-induced proteotype, we compared the protein profiles of two isogenic canine OS cell lines, POS (low metastatic) and HMPOS (highly metastatic), under normoxia and hypoxia. Label-free shotgun proteomics was applied to comprehensively characterize the hypoxia-responsive proteome profiles in the OS cell phenotypes. Hypothesis-driven parallel reaction monitoring was used to validate the differential proteins observed in the shotgun data and to monitor proteins of which we expected to exhibit hypoxia responsiveness, but which were absent in the label-free shotgun data. We established a "distance" score (|zHMPOS - zPOS|), and "sensitivity" score (|zHypoxia - zNormoxia) to quantitatively evaluate the proteome shifts exhibited by OS cells in response to hypoxia. Evaluation of the sensitivity scores for the proteome shifts observed and principal component analysis of the hypoxia-responsive proteins indicated that both cell types acquire a proteome that supports a Warburg phenotype with enhanced cell migration and proliferation characteristics. Cell migration and glucose uptake assays combined with protein function inhibitor studies provided further support that hypoxia-driven adaption of pathways associated with glycolytic metabolism, collagen biosynthesis and remodeling, redox regulation and immunomodulatory proteins typify a proteotype associated with an aggressive cancer cell phenotype. Our findings further suggest that proteins involved in collagen remodeling and immune editing may warrant further evaluation as potential targets for anti-metastatic treatment strategies in osteosarcoma.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

miRNA-30c can be used as a target in the diagnosis and treatment of osteosarcoma

Objective

Osteosarcoma is a highly malignant osseous sarcoma with poor prognosis. Previous studies indicated that miRNA-30c may play an important role in the development of osteosarcoma, but its mechanism is not yet clear. The current research was carried out to explore the potential applications of miR-30c in the diagnosis and treatment of osteosarcoma.

Materials and methods

Real-time PCR and in situ hybridization were used to test the correlation between miR-30c and the onset of osteosarcoma. In vitro transfection of miR-30 mimic was used to test the effect of miR-30c on the development of osteosarcoma. Cell Counting Kit-8, formation of Petri dish clones, in vivo formation of tumor, flow cytometry tests and Transwell analysis were used to assess the effect of miR-330c on the metastatic potential and invasiveness of osteosarcoma.

Results

Reverse transcriptase-PCR analysis and in situ hybridization tests revealed that the expression of miR-30c was lower in the osteosarcoma tissue than in normal bone tissue (P<0.05). Low expression of miR-30c was associated with advanced osteosarcoma staging and low cellular differentiation. Multivariate analysis revealed that lower expression of miR-30c was associated with shorter survival of patients (P<0.01). U2OS cell growth was significantly inhibited when transfected with miR-30c mimic. Flow cytometry analysis revealed that overexpression of miR-30c could induce apoptosis of osteosarcoma cells. In vitro Petri dish cloning experiment showed that overexpression of miR-30c reduced the cloning ratio of U2OS cells from 21% to 7%. At the same time, overexpression of miR-30c inhibited the formation of sarcoma in nude mice. Transwell experiments indicated that overexpression of miR-30c could reduce the invasiveness of U2OS cells.

Conclusion

Low expression of miR-30c was associated with high probability of onset and aggressiveness of osteosarcoma and shorter patient survival. Upregulation of miR-30c could downregulate the invasiveness of osteosarcoma. Therefore, miR-30 can be used in the development of future diagnostic and therapeutic techniques.

SLC34A2 Regulates the Proliferation, Migration, and Invasion of Human Osteosarcoma Cells Through PTEN/PI3K/AKT Signaling

Osteosarcoma (OS) is a bone malignancy with high incidence. The underlying molecular mechanisms that are associated with the development of OS need further investigation. In this study, we showed that SLC34A2, a member of the solute carrier gene family, was significantly downregulated in OS patients and cell lines. Overexpression of SLC34A2 inhibited the proliferation, migration, and invasion of OS cells. Mechanistically, we found that SLC34A2 interacted with PTEN, and inactivated the PI3K/AKT signaling pathway. Collectively, our results demonstrated that SLC34A2 plays important roles in regulating the cancer cell growth of OS. The downregulation of SLC34A2 in OS patients suggested that it might be a promising target in the diagnosis and therapy of OS.

MicroRNAs with prognostic significance in osteosarcoma: a systemic review and meta-analysis

Introduction

This study aimed to elucidate the prognostic value of microRNAs (miRNAs) in patients with osteosarcoma.

Materials and Methods

Studies were recruited by searching PubMed, Embase, the Cochrane Library, China National Knowledge Infrastructure, and Wanfang data-bases (final search update conducted January 2017). Eligible studies were identified and the quality was assessed using multiple search strategies.

Results

A total of 55 articles that investigated the correlation between miRNA expression and either patient survival or disease recurrence in osteosarcoma was initially identified. Among these, 30 studies were included in the meta-analysis. The results of our meta-analysis revealed that elevated levels of miR-21, miR-214, miR-29, miR-9 and miR-148a were associated with poor prognosis in osteosarcoma. Additionally, downregulated miR-382, miR26a, miR-126, miR-195 and miR-124 expression indicated poor prognosis in osteosarcoma.

Conclusions

miRNAs may act as independent prognostic factors in patients with osteosarcoma and are useful in stratifying risk.

An imprinted non-coding genomic cluster at 14q32 defines clinically relevant molecular subtypes in osteosarcoma across multiple independent datasets

Background

A microRNA (miRNA) collection on the imprinted 14q32 MEG3 region has been associated with outcome in osteosarcoma. We assessed the clinical utility of this miRNA set and their association with methylation status.

Methods

We integrated coding and non-coding RNA data from three independent annotated clinical osteosarcoma cohorts (n = 65, n = 27, and n = 25) and miRNA and methylation data from one in vitro (19 cell lines) and one clinical (NCI Therapeutically Applicable Research to Generate Effective Treatments (TARGET) osteosarcoma dataset, n = 80) dataset. We used time-dependent receiver operating characteristic (tdROC) analysis to evaluate the clinical value of candidate miRNA profiles and machine learning approaches to compare the coding and non-coding transcriptional programs of high- and low-risk osteosarcoma tumors and high- versus low-aggressiveness cell lines. In the cell line and TARGET datasets, we also studied the methylation patterns of the MEG3 imprinting control region on 14q32 and their association with miRNA expression and tumor aggressiveness.

Results

In the tdROC analysis, miRNA sets on 14q32 showed strong discriminatory power for recurrence and survival in the three clinical datasets. High- or low-risk tumor classification was robust to using different microRNA sets or classification methods. Machine learning approaches showed that genome-wide miRNA profiles and miRNA regulatory networks were quite different between the two outcome groups and mRNA profiles categorized the samples in a manner concordant with the miRNAs, suggesting potential molecular subtypes. Further, miRNA expression patterns were reproducible in comparing high-aggressiveness versus low-aggressiveness cell lines. Methylation patterns in the MEG3 differentially methylated region (DMR) also distinguished high-aggressiveness from low-aggressiveness cell lines and were associated with expression of several 14q32 miRNAs in both the cell lines and the large TARGET clinical dataset. Within the limits of available CpG array coverage, we observed a potential methylation-sensitive regulation of the non-coding RNA cluster by CTCF, a known enhancer-blocking factor.

Conclusions

Loss of imprinting/methylation changes in the 14q32 non-coding region defines reproducible previously unrecognized osteosarcoma subtypes with distinct transcriptional programs and biologic and clinical behavior. Future studies will define the precise relationship between 14q32 imprinting, non-coding RNA expression, genomic enhancer binding, and tumor aggressiveness, with possible therapeutic implications for both early- and advanced-stage patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-017-0465-4) contains supplementary material, which is available to authorized users.

miR-454 functions as an oncogene by inhibiting CHD5 in hepatocellular carcinoma

Previous studies showed that miR-454 acted as an oncogene or tumor suppressor in cancer. However, its function in HCC remains unknown. In this study, we found that miR-454 expression was upregulated in HCC cell lines and tissues. Knockdown of miR-454 inhibited HCC cell proliferation and invasion and epithelial mesenchymal transition (EMT), whereas overexpression of miR-454 promoted HCC cell proliferation and invasion and EMT. Furthermore, we identified the CHD5 as a direct target of miR-454. CHD5 was downregulated in HCC tissues and cell lines and the expression level of CHD5 was inversely correlated with the expression of miR-454 in HCC tissues. In addition, knockdown of miR-454 inhibited the growth of HepG2-engrafted tumors in vivo. Taken together, these results indicated that miR-454 functioned as an oncogene in HCC.

miR-125b and miR-100 Are Predictive Biomarkers of Response to Induction Chemotherapy in Osteosarcoma

Osteosarcoma is the most common primary malignancy in bone. Patients who respond poorly to induction chemotherapy are at higher risk of adverse prognosis. The molecular basis for such poor prognosis remains unclear. We investigated miRNA expression in eight open biopsy samples to identify miRNAs predictive of response to induction chemotherapy and thus maybe used for risk stratification therapy. The samples were obtained from four patients with inferior necrosis (Huvos I/II) and four patients with superior necrosis (Huvos III/IV) following induction chemotherapy. We found six miRNAs, including miR-125b and miR-100, that were differentially expressed > 2-fold (p < 0.05) in patients who respond poorly to treatment. The association between poor prognosis and the abundance of miR-125b and miR-100 was confirmed by quantitative reverse transcriptase-polymerase chain reaction in 20 additional osteosarcoma patients. Accordingly, overexpression of miR-125b and miR-100 in three osteosarcoma cell lines enhanced cell proliferation, invasiveness, and resistance to chemotherapeutic drugs such as methotrexate, doxorubicin, and cisplatin. In addition, overexpression of miR-125b blocked the ability of these chemotherapy agents to induce apoptosis. As open biopsy is routinely performed to diagnose osteosarcoma, levels of miR-125b and miR-100 in these samples may be used as basis for risk stratification therapy.

Non-coding RNAs including miRNAs, piRNAs, and tRNAs in human cancer

Over 98% of our genes code for RNA transcripts that will never become translated into protein. Numerous non-coding RNA (ncRNA) transcripts are structurally and functionally diverse. In particular, micro RNAs (miRNAs), piwi-interacting RNAs (piRNAs), and, more recently, transfer RNAs (tRNAs) are implicated as regulators of key genes and processes that are involved in various human diseases, including cancer. Here, we summarize the recent findings and perspectives in the small RNA and cancer research.

ZD6474, a new treatment strategy for human osteosarcoma, and its potential synergistic effect with celecoxib

ZD6474, a small molecule VEGFR and EGFR tyrosine kinase inhibitor, has been considered as a promising tumor-targeted drug in various malignancies. EGFR and cyclooxygenase-2 (COX-2) were found overexpressed in osteosarcoma in previous reports, so here we tried to explore the anti-osteosarcoma effect of ZD6474 alone or combination with celecoxib, a COX-2 inhibitor. The data demonstrated that ZD6474 inhibited the growth of osteosarcoma cells, and promoted G1-phase cell cycle arrest and apoptosis by inhibiting the activity of EGFR tyrosine kinase, and consequently suppressing its downstream PI3k/Akt and MAPK/ERK pathway. Additionally, daily administration of ZD6474 produced a dose-dependent inhibition of tumor growth in nude mice. Celecoxib also significantly inhibited the growth of osteosarcoma cells in dose-dependent manner, while combination of ZD6474 and celecoxib displayed a synergistic or additive antitumor effect on osteosarcoma in vitro and in vivo. The possible molecular mechanisms to address the synergism are likely that ZD6474 induces the down-regulation of COX-2 expression through inhibiting ERK phosphorylation, while celecoxib promotes ZD6474-directed inhibition of ERK phosphorylation. In conclusion, ZD6474 exerts direct anti-proliferative effects on osteosarcoma cells, and the synergistic antitumor effect of the combination of ZD6474 with celecoxib may indicate a new strategy of the combinative treatment of human osteosarcoma.

MicroRNAs in apoptosis, autophagy and necroptosis

MicroRNAs (miRNAs) are endogenous 22 nt non-coding RNAs that target mRNAs for cleavage or translational repression. Numerous miRNAs regulate programmed cell death including apoptosis, autophagy and necroptosis. We summarize how miRNAs regulate apoptotic, autophagic and necroptotic pathways and cancer progression. We also discuss how miRNAs link different types of cell death.

JNK pathway in osteosarcoma: pathogenesis and therapeutics

CONTEXT

The c-Jun NH2-terminal kinase (JNK) is a member of the mitogen-activated protein kinase super family. JNK can phosphorylate a number of activator protein-1 components, activating several transcription factors, and thus, JNK signaling pathway is being involved in several carcinogenic mechanisms.

OBJECTIVE

In this study, we have reviewed the recent updates of the association of JNK pathway with osteosarcoma (OS), which is one of the most common and aggressive bone malignancies.

METHODS

In this review, we have explored the databases like PubMed, Google Scholar, MEDLINE, etc., and collected the most relevant papers of JNK signaling pathway involved in the pathogenesis and therapeutics of OS.

RESULTS

Evidence showed that JNK is a master protein kinase that plays an important role in osteoblast proliferation, differentiation and apoptosis. Interesting reports showed that chemical JNK inhibitors reduce OS cell proliferation and metastasis. Many of the components of this pathway have now been identified and the application of JNK inhibitors has been proven to work in vivo in human and in animal models; however, JNK pathway has not been translated into clinical use.

CONCLUSION

Therapeutic interventions of potent and selective inhibitors of JNK might provide promising therapeutic approaches for the treatment of OS, and could improve the survival rate and quality of life of OS patients.

The role of microRNAs expression in laryngeal cancer

MicroRNAs (miRs, miRs) is a class of small non-coding RNAs, which posttranscriptionally regulate gene expression. Deregulated miRs are frequently obseved in patients with laryngeal cancer. In addition, numerous studies have showed miRs play significant roles in the pathogenesis of laryngeal cancer through regulating tumor cell proliferation, metastasis, invasion and apoptosis. miR can play either an oncogenic or tumor suppressive role in laryngeal cancer. In our review, we summarize the recent researches on laryngeal cancer-associated miRs, focusing on their role in the pathogenesis of laryngeal cancer. As changes in the levels of specific miRs in tissues or serum associate with diagnosis and prognosis of patients, we will also discuss the potential use of miRs in laryngeal cancer diagnosis and prognosis. Furthermore, supplementation of oncomiRs or inhibition of tumor suppressive miRs in vivo may be future therapeutic strategy for laryngeal cancer.

MicroRNA-23a enhances migration and invasion through PTEN in osteosarcoma

To investigate the biological significance of abundant microRNA-23a (miR-23a) expression in osteosarcoma and its correlation with PTEN in the pathogenesis of osteosarcoma migration and invasion. The human osteosarcoma cell lines MG63, HOS58 and SaoS-2, and the human normal osteoblasts (hFOB1.19) were grown in RPMI 1640 medium supplemented with 10% fetal bovine serum. Gene and protein levels of miR-23a and PTEN were examined to determine the molecular relationship between them in the pathogenesis of osteosarcoma. Inhibition of miR-23a effectively reduced migration and invasion of osteosarcoma cell lines. Bioinformatics and luciferase-reporter assay revealed that miR-23a specifically targeted the 3'-untranslational region of PTEN and regulated its expression. Downregulation of PTEN enhanced migration and invasion of osteosarcoma cell lines. Furthermore, in tumor tissues obtained from osteosarcoma patients, the expression of miR-23a was negatively correlated with PTEN and the high expression of miR-23a combined with low expression of PTEN might serve as a risk factor for cancer patients. Besides, miR-23a-mediated suppression of PTEN led to activation of AKT/ERK pathways and epithelial-mesenchymal transition (EMT) in osteosarcoma cells, and finally enhanced the activity of osteosarcoma cell proliferation and movement and promoted osteosarcoma xenograft tumor growth in mouse models. Our study showed that miR-23a, by downregulation of PTEN, enhanced migration and invasion in osteosarcoma cells.

MicroRNA expression and its implications for diagnosis and therapy of gallbladder cancer

Gallbladder cancer is the most common biliary tract malignancy with poor prognosis. MicroRNAs (miRNAs) are a class of small, endogenous, non-coding RNAs of 19-23 nucleotides in length, which regulate gene expression at post-transcriptional and translational levels. Several studies have demonstrated aberrant expression of miRNAs in gallbladder cancer tissues. Recent evidences also demonstrated that specific miRNAs are functionally involved in gallbladder cancer development through modulating cell proliferation, apoptosis, migration, invasion and metastasis. In this review, we explore the possibilities of using miRNAs as prognostic, diagnostic markers and therapeutic targets in gallbladder cancer.

P53 suppresses cell proliferation, metastasis, and angiogenesis of osteosarcoma through inhibition of the PI3K/AKT/mTOR pathway

OBJECTIVE

To investigate the role of P53 in the pathogenesis of osteosarcoma and the possible mechanism involved in it.

METHODS

The anti-proliferative effect of P53 was assessed using the cell counting Kit-8 assay. The migration and invasion potential were analyzed using wound-healing and transwell assays, respectively. The Matrigel capillary tube formation assay was performed to mimic in-vivo angiogenesis. Immunoblotting and immunofluorescence were used to observe protein levels and distribution of actin fibers. Finally, S2448p-mammalian target of rapamycin (mTOR) expression was detected on osteosarcoma tissues using immunohistochemistry.

RESULTS

Firstly, P53 potently inhibited cell proliferation in osteosarcoma cell line (MG63) and in human normal osteoblasts (hFOB1.19) in vitro at the IC50 ranged from 50 to 500 nmol/l. Then, an inhibitory effect of P53 on metastasis was observed in osteosarcoma cell line MG63, along with the cytoskeletal rearrangements and suppression of the phosphorylation of PI3K downstream factors including AKT and mTOR.

CONCLUSION

These results show that P53 suppresses cell proliferation and angiogenesis of osteosarcoma through inhibition of the PI3K/AKT/mTOR pathway, which might be an effective novel therapeutic candidate against osteosarcoma in the future.