MAPK7 and MAP2K4 as prognostic markers in osteosarcoma

Research and progress of microRNA-136 in metastatic tumors

Background

MiR-136 is abnormally expressed in many types of metastatic tumors and is closely associated with tumor cell proliferation, apoptosis, invasion, and metastasis, indicating its important role in tumor development and progression. This review summarizes current knowledge regarding miR-136's molecular mechanisms, functional roles, and impact on chemotherapy in different human cancers.

Methods

A literature search was conducted in PubMed and Web of Science using "miR-136" and "metastatic tumors" as English keywords, and in CNKI and Wanfang databases using the same terms in Chinese. Studies related to miR-136 research in metastatic tumors and high-quality evidence from similar studies were included. Meta-analyses, dissertations, conference papers, low-quality articles, unavailable full-text articles, and republished articles were excluded.

Results

This review synthesizes the current understanding of miR-136's role in various cancers, including osteosarcoma, gastric cancer, gallbladder cancer, esophageal cancer, prostate cancer, colorectal cancer, breast cancer, glioma, and thyroid cancer. miR-136 acts as a tumor suppressor by targeting various genes, including MTDH, PTEN, MAP2K4, MUC1, LRH-1, MIEN1, RASAL2, CYR61, and KLF7. It influences multiple signaling pathways, including the ERK/mitogen-activated protein kinase, Wnt/β-catenin, Ha-Ras, PI3K/Akt, Aurora-A kinase, nuclear factor-κB, and JNK pathways. Furthermore, miR-136 is involved in chemoresistance by modulating ROCK1, PPP2R2A, and the miR-136-Notch3 signaling axis.

Conclusions

MiR-136 demonstrates promising potential as a novel biomarker and therapeutic target in various human cancers. Further research is needed to fully elucidate its complex roles in cancer development, progression, and drug resistance, particularly regarding its potential in immunotherapy.

IGFBP5 in osteosarcoma tumorigenesis: Gene expression profile among metastatic and non-metastatic patients

Osteosarcoma (OS) is the most frequent primary malignant bone tumor among children and adolescents, with a peak of incidence in the second decade of life. The presence of metastasis at diagnosis in OS patients significantly decreases the chances of survival and new therapy approaches are needed. The IGFBP5 gene is related to osteoblasts metabolism and some studies have pointed out a role of its low expressions in OS development and metastasis. In this study, we aimed to establish an IGFBP5 gene expression profile among metastatic and non-metastatic OS patients throughout the treatment and development of the disease. Fresh-frozen tumor samples were obtained from 40 patients admitted to treatment at the Pediatric Oncology Institute (IOP/GRAACC/UNIFESP) and divided by clinical status: metastatic or non-metastatic disease. For each patient, samples before and after chemotherapy treatment were obtained, as well as metastasis and lung tissue surrounding metastasis samples from the metastatic patients. A quantitative real-time PCR was used to investigate IGFBP5 expression. Our analyses demonstrate that non-metastatic patients presented lower IGFBP5 expression in their pre-chemotherapy samples compared with metastatic patients, suggesting that low expressions of this gene could help triggering the OS tumorigenesis but that its action alone is not sufficient to activate the metastatic process. Heterogeneity in IGFBP5 expressions within groups was also seen. We observed that IGFBP5 and two MAPK genes, a downstream pathway in the IGFBP5 axis, are differentially expressed in OS samples of non-metastatic patients. Further investigation about these genes' modulations might lead to a better understanding of metastasis development in OS.

Bone and Extracellular Signal-Related Kinase 5 (ERK5)

Bones are vital for anchoring muscles, tendons, and ligaments, serving as a fundamental element of the human skeletal structure. However, our understanding of bone development mechanisms and the maintenance of bone homeostasis is still limited. Extracellular signal-related kinase 5 (ERK5), a recently identified member of the mitogen-activated protein kinase (MAPK) family, plays a critical role in the pathogenesis and progression of various diseases, especially neoplasms. Recent studies have highlighted ERK5's significant role in both bone development and bone-associated pathologies. This review offers a detailed examination of the latest research on ERK5 in different tissues and diseases, with a particular focus on its implications for bone health. It also examines therapeutic strategies and future research avenues targeting ERK5.

ERK5 Signalling and Resistance to ERK1/2 Pathway Therapeutics: The Path Less Travelled?

The RAS-regulated RAF-MEK1/2-ERK1/2 signalling pathway is frequently de-regulated in human cancer. Melanoma in particular exhibits a high incidence of activating BRAFV600E/K and NRASQ61L/K mutations and such cells are addicted to the activity of these mutant oncoproteins. As a result three different BRAF inhibitors (BRAFi) have now been approved for BRAFV600E/K- mutant melanoma and have transformed the treatment of this disease. Despite this, clinical responses are typically transient as tumour cells develop resistance. These resistance mechanisms frequently involve reinstatement of ERK1/2 signalling and BRAFi are now deployed in combination with one of three approved MEK1/2 inhibitors (MEKi) to provide more durable, but still transient, clinical responses. Furthermore, inhibitors to ERK1/2 (ERK1/2i) have also been developed to counteract ERK1/2 signalling. However, recent studies have suggested that BRAFi/MEKi and ERK1/2i resistance can arise through activation of a parallel signalling pathway leading to activation of ERK5, an unusual protein kinase that contains both a kinase domain and a transcriptional transactivation domain. Here we review the evidence supporting ERK5 as a mediator of BRAFi/MEKi and ERK1/2i resistance. We also review the challenges in targeting ERK5 signalling with small molecules, including paradoxical activation of the transcriptional transactivation domain, and discuss new therapeutic modalities that could be employed to target ERK5.

Clinical Significance and Regulation of ERK5 Expression and Function in Cancer

Extracellular signal-regulated kinase 5 (ERK5) is a unique kinase among MAPKs family members, given its large structure characterized by the presence of a unique C-terminal domain. Despite increasing data demonstrating the relevance of the ERK5 pathway in the growth, survival, and differentiation of normal cells, ERK5 has recently attracted the attention of several research groups given its relevance in inflammatory disorders and cancer. Accumulating evidence reported its role in tumor initiation and progression. In this review, we explore the gene expression profile of ERK5 among cancers correlated with its clinical impact, as well as the prognostic value of ERK5 and pERK5 expression levels in tumors. We also summarize the importance of ERK5 in the maintenance of a cancer stem-like phenotype and explore the major known contributions of ERK5 in the tumor-associated microenvironment. Moreover, although several questions are still open concerning ERK5 molecular regulation, different ERK5 isoforms derived from the alternative splicing process are also described, highlighting the potential clinical relevance of targeting ERK5 pathways.

Targeting the MAPK7/MMP9 axis for metastasis in primary bone cancer

Metastasis is the leading cause of cancer-related death. This multistage process involves contribution from both tumour cells and the tumour stroma to release metastatic cells into the circulation. Circulating tumour cells (CTCs) survive circulatory cytotoxicity, extravasate and colonise secondary sites effecting metastatic outcome. Reprogramming the transcriptomic landscape is a metastatic hallmark, but detecting underlying master regulators that drive pathological gene expression is a key challenge, especially in childhood cancer. Here we used whole tumour plus single-cell RNA-sequencing in primary bone cancer and CTCs to perform weighted gene co-expression network analysis to systematically detect coordinated changes in metastatic transcript expression. This approach with comparisons applied to data collected from cell line models, clinical samples and xenograft mouse models revealed mitogen-activated protein kinase 7/matrix metallopeptidase 9 (MAPK7/MMP9) signalling as a driver for primary bone cancer metastasis. RNA interference knockdown of MAPK7 reduces proliferation, colony formation, migration, tumour growth, macrophage residency/polarisation and lung metastasis. Parallel to these observations were reduction of activated interleukins IL1B, IL6, IL8 plus mesenchymal markers VIM and VEGF in response to MAPK7 loss. Our results implicate a newly discovered, multidimensional MAPK7/MMP9 signalling hub in primary bone cancer metastasis that is clinically actionable.

MicroRNAs signatures, bioinformatics analysis of miRNAs, miRNA mimics and antagonists, and miRNA therapeutics in osteosarcoma

MicroRNAs (miRNAs) involved in key signaling pathways and aggressive phenotypes of osteosarcoma (OS) was discussed, including PI3K/AKT/MTOR, MTOR AND RAF-1 signaling, tumor suppressor P53- linked miRNAs, NOTCH- related miRNAs, miRNA -15/16 cluster, apoptosis related miRNAs, invasion-metastasis-related miRNAs, and 14Q32-associated miRNAs cluster. Herrin, we discussed insights into the targeted therapies including miRNAs (i.e., tumor-suppressive miRNAs and oncomiRNAs). Using bioinformatics tools, the interaction network of all OS-associated miRNAs and their targets was also depicted.

MAPK7 variants related to prognosis and chemotherapy response in osteosarcoma

Osteosarcoma (OS) is a class of cancer originating from the bone, affecting mainly children and young adults. Our previous study showed that MAPK7 gene overexpression was significantly associated with tumor progression, poor treatment response, and worse overall survival, suggesting that MAPK7 could play an important role in OS tumorigenesis. We have investigated if MAPK7 overexpression was a result of any genomic changes in OS tumor specimens. We identified five SNPs (Single Nucleotide Polymorphism) previously described in databases, dbSNP and COSMIC, and identified two single nucleotide substitution not yet described. We found, in prechemotherapy specimens, a significant association of MAPK7 rs2233072G allele variant with metastasis at diagnosis and relapse (0.0909 and 0.0455, respectively). In post-chemotherapy, rs1054206GG specimen's genotype was associated with osteoblastic histological type (P= 0.0249) and presented decreased MAPK7 gene expression when compared with pre-chemotherapy specimens of same patients (P = 0.0095). Interestingly, it was observed some SNPs genotype exchange after chemotherapy. Our data indicated that MAPK7 gene expression associated with genotype exchange after chemotherapy, and these SNPs associated with important clinical parameters might be a valuable indicator for predicting in OS.

MicroRNA gga-miR-200a-3p modulates immune response via MAPK signaling pathway in chicken afflicted with necrotic enteritis

MicroRNAs (miRNAs) are small non-coding RNAs that contribute to host immune response as post-transcriptional regulation. The current study investigated the biological role of the chicken (Gallus gallus) microRNA-200a-3p (gga-miR-200a-3p), using 2 necrotic enteritis (NE) afflicted genetically disparate chicken lines, 6.3 and 7.2, as well as the mechanisms underlying the fundamental signaling pathways in chicken. The expression of gga-miR-200a-3p in the intestinal mucosal layer of NE-induced chickens, was found to be upregulated during NE infection in the disease-susceptible chicken line 7.2. To validate the target genes, we performed an overexpression analysis of gga-miR-200a-3p using chemically synthesized oligonucleotides identical to gga-miR-200a-3p, reporter gene analysis including luciferase reporter assay, and a dual fluorescence reporter assay in cultured HD11 chicken macrophage cell lines. Gga-miR-200a-3p was observed to be a direct transcriptional repressor of ZAK, MAP2K4, and TGFβ2 that are involved in mitogen-activated protein kinase (MAPK) pathway by targeting the 3′-UTR of their transcripts. Besides, gga-miR-200a-3p may indirectly affect the expression of protein kinases including p38 and ERK1/2 at both transcriptional and translational levels, suggesting that this miRNA may function as an important regulator of the MAPK signaling pathway. Proinflammatory cytokines consisting of IL-1β, IFN-γ, IL-12p40, IL-17A, and LITAF belonging to Th1 and Th17-type cytokines, were upregulated upon gga-miR-200a-3p overexpression. These findings have enhanced our knowledge of the immune function of gga-miR-200a-3p mediating the chicken immune response via regulation of the MAPK signaling pathway and indicate that this miRNA may serve as an important biomarker of diseases in domestic animals.

An Insight into the Roles of MicroRNAs and Exosomes in Sarcoma

Sarcomas are rare solid tumors, but at least one-third of patients with sarcoma die from tumor-related disease. MicroRNA (miRNA) is a noncoding RNA that regulates gene expression in all cells and plays a key role in the progression of cancers. Recently, it was identified that miRNAs are transferred between cells by enclosure in extracellular vesicles, especially exosomes. The exosome is a 100 nm-sized membraned vesicle that is secreted by many kinds of cells and contains miRNA, mRNA, DNA, and proteins. Cancer uses exosomes to influence not only the tumor microenvironment but also the distant organ to create a premetastatic niche. The progression of sarcoma is also regulated by miRNAs and exosomes. These miRNAs and exosomes can be targeted as biomarkers and treatments. In this review, we summarize the studies of miRNA and exosomes in sarcoma.

Impact of ERK5 on the Hallmarks of Cancer

Extracellular signal-regulated kinase 5 (ERK5) belongs to the mitogen-activated protein kinase (MAPK) family that consists of highly conserved enzymes expressed in all eukaryotic cells and elicits several biological responses, including cell survival, proliferation, migration, and differentiation. In recent years, accumulating lines of evidence point to a relevant role of ERK5 in the onset and progression of several types of cancer. In particular, it has been reported that ERK5 is a key signaling molecule involved in almost all the biological features of cancer cells so that its targeting is emerging as a promising strategy to suppress tumor growth and spreading. Based on that, in this review, we pinpoint the hallmark-specific role of ERK5 in cancer in order to identify biological features that will potentially benefit from ERK5 targeting.

MicroRNA‑136 inhibits prostate cancer cell proliferation and invasion by directly targeting mitogen‑activated protein kinase kinase 4

Prostate cancer (PCa) is the second most common type of cancer and the 6th leading cause of cancer‑associated mortality worldwide. Accumulated evidence suggests that PCa initiation and progression are controlled by microRNAs (miRNAs). Therefore, investigating PCa‑associated miRNAs may provide novel biomarkers for the diagnosis and treatment of patients with PCa. In the present study it was demonstrated that miRNA‑136 (miR‑136) expression was significantly downregulated in PCa tissues and cell lines. The resumption of miR‑136 expression suppressed cell proliferation and invasion in PCa cells. Bioinformatics analysis predicted that mitogen‑activated protein kinase kinase 4 (MAP2K4) was a direct target of miR‑136. This prediction was experimentally confirmed by a luciferase reporter assay, RT‑qPCR and western blot analysis. MAP2K4 was highly expressed in PCa tissues and inversely correlated with the miR‑136 expression level. Additionally, the restoration of MAP2K4 expression significantly blocked the inhibitory effects of miR‑136 on cell proliferation and invasion in PCa cells. Therefore, miR‑136 may suppress the proliferation and invasion of PCa cells by targeting MAP2K4 and may be a novel candidate target for cancer therapy against PCa.

The systemic tumor response to RNase A treatment affects the expression of genes involved in maintaining cell malignancy

Recently, pancreatic RNase A was shown to inhibit tumor and metastasis growth that accompanied by global alteration of miRNA profiles in the blood and tumor tissue (Mironova et al., 2013). Here, we performed a whole transcriptome analysis of murine Lewis lung carcinoma (LLC) after treatment of tumor-bearing mice with RNase A. We identified 966 differentially expressed transcripts in LLC tumors, of which 322 were upregulated and 644 were downregulated after RNase A treatment. Many of these genes are involved in signaling pathways that regulate energy metabolism, cell-growth promoting and transforming activity, modulation of the cancer microenvironment and extracellular matrix components, and cellular proliferation and differentiation. Following RNase A treatment, we detected an upregulation of carbohydrate metabolism, inositol phosphate cascade and oxidative phosphorylation, re-arrangement of cell adhesion, cell cycle control, apoptosis, and transcription. Whereas cancer-related signaling pathways (e.g., TGF-beta, JAK/STAT, and Wnt) were downregulated following RNase A treatment, as in the case of the PI3K/AKT pathway, which is involved in the progression of non-small lung cancer. RNase A therapy resulted in the downregulation of genes that inhibit the biogenesis of some miRNAs, particularly the let-7 miRNA family.

Taken together, our data suggest that the antitumor activity and decreased invasion potential of tumor cells caused by RNase A are associated with enhanced energy cascade functioning, rearrangement of cancer-related events regulating cell growth and dissemination, and attenuation of signaling pathways having tumor-promoting activity. Thus, RNase A can be proposed as a potential component of anticancer therapy with multiple modes of action.

MiR-143 regulates the proliferation and migration of osteosarcoma cells through targeting MAPK7

Accumulating documents have been suggested that microRNA-143 (miR-143) function as a tumor suppressor, involved in many biological processes including tumor initiation and progression. However, the biological function and molecular mechanism of miR-143 in Osteosarcoma (OS) still remains to be further investigated. Despite many efforts have been made, the prognosis of OS is still unsatisfied. Thus, exploring the underlying mechanism of OS and finding new treatment targets is essential for improving the survival rate of OS patients. In our study, we determined the level of miR-143 in clinical OS tissues and cells, and explored its function and underlying mechanisms in the tumorigenesis of OS. Our findings revealed that miR-143 expression was significantly downregulated in OS tissues and cell lines. Gain-of-function assays indicated that forced expression of miR-143 in OS cells inhibited cell proliferation and migration/invasion. Bioinformatics and luciferase reporter assays confirmed that MAPK7 was targets gene of miR-143. The results of the present study indicated that miR-143 could be a potential target for treating OS.

The Microtubule Network and Cell Death Are Regulated by an miR-34a/Stathmin 1/βIII-Tubulin Axis

MicroRNA-34a (miR-34a) is a master regulator of signaling networks that maintains normal physiology and disease and is currently in development as a miRNA-based therapy for cancer. Prior studies have reported low miR-34a expression in osteosarcoma; however, the molecular mechanisms underlying miR-34a activity in osteosarcoma are not well-defined. Therefore, this study evaluated the role of miR-34a in regulating signal transduction pathways that influence cell death in osteosarcoma. Levels of miR-34a were attenuated in human osteosarcoma cells and xenografts of the Pediatric Preclinical Testing Consortium (PPTC). Bioinformatics predictions identified stathmin 1 (STMN1) as a potential miR-34a target. Biotin pull-down assay and luciferase reporter analysis confirmed miR-34a target interactions within the STMN1 mRNA 3'-untranslated region. Overexpression of miR-34a in osteosarcoma cells suppressed STMN1 expression and reduced cell growth in vitro Restoration of miR-34a led to microtubule destabilization and increased βIII-tubulin expression, with corresponding G1-G2 phase cell-cycle arrest and apoptosis. Knockdown of the Sp1 transcription factor, by siRNA silencing, also upregulated βIII-tubulin expression in osteosarcoma cells, suggesting that miR-34a indirectly affects Sp1. Validating the coordinating role of miR-34a in microtubule destabilization, when miR-34a was combined with either microtubule inhibitors or chemotherapy, STMN1 phosphorylation was suppressed and there was greater cytotoxicity in osteosarcoma cells. These results demonstrate that miR-34a directly represses STMN1 gene and protein expression and upregulates βIII-tubulin, leading to disruption of the microtubule network and cell death.Implications: The miR-34a/STMN1/βIII-tubulin axis maintains the microtubule cytoskeleton in osteosarcoma, and combining miR-34a with microtubule inhibitors can be investigated as a novel therapeutic strategy. Mol Cancer Res; 15(7); 953-64. ©2017 AACR.

Oncogenic signaling of MEK5-ERK5

Mitogen-activated protein kinases (MAPKs) regulate diverse cellular processes including proliferation, cell survival, differentiation, and apoptosis. While conventional MAPK constituents have well-defined roles in oncogenesis, the MEK5 pathway has only recently emerged in cancer research. In this review, we consider the MEK5 signaling cascade, focusing specifically on its involvement in drug resistance and regulation of aggressive cancer phenotypes. Moreover, we explore the role of MEK5/ERK5 in tumorigenesis and metastatic progression, discussing the discrepancies in preclinical studies and assessing its viability as a therapeutic target for anti-cancer agents.

MicroRNA-802 plays a tumour suppressive role in tongue squamous cell carcinoma through directly targeting MAP2K4

OBJECTIVES

Tongue squamous cell carcinoma (TSCC) is the most common oral tumours. MicroRNAs play crucial roles in many cell processes including cell viability, development, apoptosis, migration and invasion. The role of miR-802 in the TSCC is still unknown.

MATERIALS AND METHODS

The miR-802 expression in TSCC tissues and cell lines was determined by quantitative real-time polymerase chain reaction. CCK-8 assay was performed to measure the cell viability, while the cell invasion assay was used to determine the cell invasion. Dual-luciferase reporter and western blot were used to confirm the potential target gene of miR-802.

RESULTS

In our study, we demonstrated that miR-802 expression was downregulated in TSCC tissues and cell lines. Elevated expression of miR-802 suppressed the TSCC cell viability and invasion. Moreover, enforced expression of miR-802 increased the expression of E-cadherin, while suppressed the expression of N-cadherin, Snail and Vimentin in the TSCC cell. In addition, we identified the mitogen-activated protein kinase 4 (MAP2K4) as a direct target gene of miR-802 in the TSCC cell. We also demonstrated that the expression of MAP2K4 was higher in the TSCC tissues than that in the adjacent normal tissues. Furthermore, the expression level of MAP2K4 was inversely associated with the expression of miR-802 in TSCC tissues. We also demonstrated that the MAP2K4 expression was upregulated in TSCC cell lines. Elevated expression of miR-802 inhibited TSCC cell viability and invasion through inhibiting MAP2K4 expression.

CONCLUSIONS

Our data revealed that miR-802 played as a tumour suppressor gene and might act as a therapeutic target in TSCC patients.

The MEK5/ERK5 signalling pathway in cancer: a promising novel therapeutic target

Conventional mitogen-activated protein kinase (MAPK) family members are among the most sought-after oncogenic effectors for the development of novel human cancer treatment strategies. MEK5/ERK5 has been the less-studied MAPK subfamily, despite its increasingly demonstrated relevance in the growth, survival, and differentiation of normal cells. MEK5/ERK5 signalling has already been proposed to have pivotal roles in several cancer hallmarks, and to mediate the effects of a range of oncogenes. Accumulating evidence indicates the contribution of MEK5/ERK5 signalling to therapy resistance and the benefits of using MEK5/ERK5 inhibitory strategies in the treatment of human cancer. Here, we explore the major known contributions of MEK5/ERK5 signalling to the onset and progression of several types of cancer, and highlight the potential clinical relevance of targeting MEK5/ERK5 pathways.

High Expression of HULC Is Associated with Poor Prognosis in Osteosarcoma Patients

Osteosarcoma (OS) is the most common primary bone cancer in childhood. OS is an aggressive disease, and metastatic patients evolve with very poor clinical outcomes. Genetically, OSs are extremely complex tumors, and the related metastatic process is not well understood in terms of the biology of the disease. In this context, long non-coding RNAs (lncRNAs) have emerged as an important class of gene expression regulators that play key roles in the invasion and metastasis of several human tumors. Here, we evaluated the expression of HULC, which is an lncRNA that is associated with the tumor metastatic process, and assessed its potential role as a prognostic marker in OS. HULC expression was evaluated in primary OS samples using real-time RT-PCR. HULC expression status was determined by receiver operating characteristic (ROC) analysis, and its association with survival was assessed using the Kaplan-Meier method. The HULC expression level was not significantly associated with the clinicopathological characteristics of the OS patients. However, our data demonstrated that higher levels of expression of HULC were associated with lower survival rates in OS patients, both in terms of overall and event-free survival. Elevated HULC expression was associated with poor clinical outcomes among the OS patients, which suggests that HULC could be a potential prognostic biomarker in OS.

MAPK7 gene controls proliferation, migration and cell invasion in osteosarcoma

Osteosarcomas (OS) are the most common malignant bone tumors, and the identification of useful tumor biomarkers and target proteins is required to predict the clinical outcome of patients and therapeutic response as well as to develop novel therapeutic strategies. In our previous study, MAPK7 has been identified as a candidate oncogene, and a promising prognostic marker for OS. Sequential activation of protein kinases within the mitogen-activated protein kinase (MAPK) cascades is a common mechanism of signal transduction in many cellular processes. In this study, we investigated the behavior of MAPK7 gene in OS cell lines. Technical viability, proliferation, migration, invasion, and apoptosis were used to evaluate the function of the MAPK7 gene. We evaluated the behavior of the OS cells with MAPK7 gene silenced, not silenced, and exposed to the main chemotherapy drugs used in OS treatment. We found that silenced MAPK7 gene is effective at suppressing cell proliferation, inhibiting cell migration, and invasion. Furthermore, MAPK7 is an important activator of transcription factors and is the main expression modulator of other key genes in the MAPK pathway. In summary, our study suggests that MAPK7 might be a promising therapeutic target for OS. © 2015 Wiley Periodicals, Inc.

Mitogen-activated protein kinase 7 promotes cell proliferation, migration and invasion in SOSP-M human osteosarcoma cell line

PURPOSE

Osteosarcoma (OS) is the most common primary bone tumor and has low cure rates. Our study aimed to evaluate the roles of mitogen-activated protein kinase 7 (MAPK7) in cell proliferation, migration and invasion using the SOSP-M human OS cell line as an in vitro model.

METHODS

SOSP-M cells were transfected with PCDNA3.1-MAPK7 and siRNA-MAPK7 plasmids using Lipofectamine 2000. Quantitative real-time polymerase chain reaction (RT-PCR) was performed to determine the relative expression level of MAPK7 and Western blot analysis was carried out to determine the expression level of ERK5 protein. Then MTT, scratch wound healing and Matrigel transwell assays were used to investigate the roles of MAPK7 expression in the proliferation, migration and invasion, respectively, of SOSP-M cells in vitro.

RESULTS

RT-PCR analysis showed that the expression level of MAPK7 increased significantly after transfection with PCDNA3.1-MAPK7 plasmid compared with the blank group, while it decreased significantly after transfection with siRNA-MAPK7 plasmid. Similar results for ERK5 expression were obtained by Western blot analysis. In addition, the cell proliferation rate, cell migration rate and invasive cell number in the PCDNA3.1-MAPK7 transfection group increased significantly compared with the blank group, while they decreased significantly in the siRNA-MAPK7 transfection group.

CONCLUSIONS

Our results indicate that overexpression of MAPK7 in human OS cells could promote cell proliferation, migration and invasion, whereas knockdown of MAPK7 expression had the opposite effect. All the results suggest that MAPK7 may serve as a potent target for drug development.

A Sleeping Beauty forward genetic screen identifies new genes and pathways driving osteosarcoma development and metastasis

Osteosarcomas are sarcomas of the bone, derived from osteoblasts or their precursors, with a high propensity to metastasize. Osteosarcoma is associated with massive genomic instability, making it problematic to identify driver genes using human tumors or prototypical mouse models, many of which involve loss of Trp53 function. To identify the genes driving osteosarcoma development and metastasis, we performed a Sleeping Beauty (SB) transposon-based forward genetic screen in mice with and without somatic loss of Trp53. Common insertion site (CIS) analysis of 119 primary tumors and 134 metastatic nodules identified 232 sites associated with osteosarcoma development and 43 sites associated with metastasis, respectively. Analysis of CIS-associated genes identified numerous known and new osteosarcoma-associated genes enriched in the ErbB, PI3K-AKT-mTOR and MAPK signaling pathways. Lastly, we identified several oncogenes involved in axon guidance, including Sema4d and Sema6d, which we functionally validated as oncogenes in human osteosarcoma.

Genomic profiling reveals distinctive molecular relapse patterns in IDH1/2 wild-type glioblastoma

Molecular changes associated with the progression of glioblastoma after standard radiochemotherapy remain poorly understood. We compared genomic profiles of 27 paired primary and recurrent IDH1/2 wild-type glioblastomas by genome-wide array-based comparative genomic hybridization. By bioinformatic analysis, primary and recurrent tumor profiles were normalized and segmented, chromosomal gains and losses identified taking the tumor cell content into account, and difference profiles deduced. Seven of 27 (26%) pairs lacked DNA copy number differences between primary and recurrent tumors (equal pairs). The recurrent tumors in 9/27 (33%) pairs contained all chromosomal imbalances of the primary tumors plus additional ones, suggesting a sequential acquisition of and/or selection for aberrations during progression (sequential pairs). In 11/27 (41%) pairs, the profiles of primary and recurrent tumors were divergent, i.e., the recurrent tumors contained additional aberrations but had lost others, suggesting a polyclonal composition of the primary tumors and considerable clonal evolution (discrepant pairs). Losses on 9p21.3 harboring the CDKN2A/B locus were significantly more common in primary tumors from sequential and discrepant (nonequal) pairs. Nonequal pairs showed ten regions of recurrent genomic differences between primary and recurrent tumors harboring 46 candidate genes associated with tumor recurrence. In particular, copy numbers of genes encoding apoptosis regulators were frequently changed at progression. In summary, approximately 25% of IDH1/2 wild-type glioblastoma pairs have stable genomic imbalances. In contrast, approximately 75% of IDH1/2 wild-type glioblastomas undergo further genomic aberrations and alter their clonal composition upon recurrence impacting their genomic profile, a process possibly facilitated by 9p21.3 loss in the primary tumor. © 2014 Wiley Periodicals, Inc.