MicroRNA-497 suppresses osteosarcoma tumor growth in vitro and in vivo

HMGA2 regulation by miRNAs in cancer: affecting cancer hallmarks and therapy response

High mobility group A 2 (HMGA2) is a protein that modulates the structure of chromatin in the nucleus. Importantly, aberrant expression of HMGA2 occurs during carcinogenesis, and this protein is an upstream mediator of cancer hallmarks including evasion of apoptosis, proliferation, invasion, metastasis, and therapy resistance. HMGA2 targets critical signaling pathways such as Wnt/β-catenin and mTOR in cancer cells. Therefore, suppression of HMGA2 function notably decreases cancer progression and improves outcome in patients. As HMGA2 is mainly oncogenic, targeting expression by non-coding RNAs (ncRNAs) is crucial to take into consideration since it affects HMGA2 function. MicroRNAs (miRNAs) belong to ncRNAs and are master regulators of vital cell processes, which affect all aspects of cancer hallmarks. Long ncRNAs (lncRNAs) and circular RNAs (circRNAs), other members of ncRNAs, are upstream mediators of miRNAs. The current review intends to discuss the importance of the miRNA/HMGA2 axis in modulation of various types of cancer, and mentions lncRNAs and circRNAs, which regulate this axis as upstream mediators. Finally, we discuss the effect of miRNAs and HMGA2 interactions on the response of cancer cells to therapy. Regarding the critical role of HMGA2 in regulation of critical signaling pathways in cancer cells, and considering the confirmed interaction between HMGA2 and one of the master regulators of cancer, miRNAs, targeting miRNA/HMGA2 axis in cancer therapy is promising and this could be the subject of future clinical trial experiments.

Long noncoding RNA AFAP1-AS1 promotes osteosarcoma progression by regulating miR-497/IGF1R axis

Long non-coding RNA (lncRNA) actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) has been reported to be involved in the progression of multiple cancers. However, exact function and regulatory mechanism of AFAP1-AS1 in osteosarcoma (OS) remain largely unclear. In this study, quantitative real time polymerase chain reaction (qRT-PCR) revealed that AFAP1-AS1 was upregulated in OS tissues and cell lines. Increased AFAP1-AS1 was associated with poor prognosis. Loss-of-function experiments demonstrated that knockdown of AFAP1-AS1 inhibited the proliferation, colony formation, migration, invasion and induced cell apoptosis. Bioinformatics analysis and luciferase reporter assays confirmed that mircoRNA-497 (miR-497) was a directly target of AFAP1-AS1. Rescue experiments confirmed that miR-497 inhibition could partially reverse the inhibitory effect of AFAP1-AS1 knockdown on OS cells. Moreover, AFAP1-AS1 modulated the expression of insulin-like growth factor 1 receptor (IGF1R, a target of miR-497) indirectly. In vivo xenograft tumor assay showed that AFAP1-AS1 knockdown inhibited tumor tumorigenesis. Taken together, these findings indicate that AFAP1-AS1 promotes OS progression by regulating miR-497/IGF1R axis, providing a therapeutic target for OS.

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.

miR-497 inhibits the carcinogenesis of hepatocellular carcinoma by targeting the Rictor/Akt signal pathway

MicroRNAs (miRNAs) are involved in regulating various physiologic and pathologic processes of different human diseases including hepatocellular carcinoma (HCC). Our research aimed to investigate the role of miR-497 in migration, invasive ability of HepG2-GS cells and the regulating mechanism. In this study, Rictor was identified as a target gene of miR-497 by informatic software, including Microcosm Targets, miRanda, and TargetScan. MiR-497 or Rictor were silenced or overexpressed in HepG2-GS cells through transfection. The functional assay results showed that Rictor knockdown inhibited cancer cell proliferation, migration and invasion. Overexpression of Rictor inversed the effects of miR-497 on cancer cells growth inhibition. miR-497 regulated protein kinase B, PKB (Akt) signaling pathway by targeting Rictor. MiR-497 increased chemo-sensitivity of HepG2-GS through regulation of Rictor. In conclusion, our research demonstrated that miR-497 inhibits the proliferation, invasion, metastasis, and chemotherapy resistance of hepatoma cells by targeting of Rictor/Akt signal pathway, and miR-497. Thus, Rictor has the potential to be a explored as a biomarker or therapeutic target for diagnosis and treatment of HCC.

The microRNAs miR-449a and miR-424 suppress osteosarcoma by targeting cyclin A2 expression

MicroRNAs of the miR-16 and miR-34 families have been reported to inhibit cell cycle progression, and their loss has been linked to oncogenic transformation. Utilizing a high-throughput, genome-wide screen for miRNAs and mRNAs that are differentially regulated in osteosarcoma (OS) cell lines, we report that miR-449a and miR-424, belonging to the miR-34 and miR-16 families, respectively, target the major S/G₂ phase cyclin, cyclin A2 (CCNA2), in a bipartite manner. We found that the 3'-UTR of CCNA2 is recognized by miR-449a, whereas the CCNA2 coding region is targeted by miR-424. Of note, we observed loss of both miR-449a and miR-424 in OS, resulting in derepression of CCNA2 and appearance of aggressive cancer phenotypes. Ectopic expression of miR-449a and miR-424 significantly decreased cyclin A2 levels and inhibited proliferation rate, migratory potential, and colony-forming ability of OS cells. To further probe the roles of miR-449a and miR-424 in OS, we developed an OS mouse model by intraosseous injection of U2OS cells into the tibia bone of NOD-scid mice, which indicated that miR-449a and miR-424 co-expression suppresses tumor growth. On the basis of this discovery, we analyzed the gene expression of human OS biopsy samples, revealing that miR-449a and miR-424 are both down-regulated, whereas cyclin A2 is significantly up-regulated in these OS samples. In summary, the findings in our study highlight that cyclin A2 repression by miRNAs of the miR-16 and miR-34 families is lost in aggressive OS.

Insights into the roles of miRNAs; miR-193 as one of small molecular silencer in osteosarcoma therapy

Today, cancer is one of the most common causes of death. Osteosarcoma (OS) is a tumor in long bones and its prevalence is high in teenagers and young people. Among the methods that used to treat cancer, one can name chemotherapy, surgery, and radiotherapy. Since these methods have some disadvantages and they are not absolutely successful, the use of microRNAs (miRNAs) is very useful in diagnosis and treatment of OS. MiRNAs are small non-coding RNA molecules, containing 18-25 nucleotides, which are involved in the regulation of gene expression via binding to messenger RNA (mRNA). These RNAs are divided into two classes of suppressors and oncogenes. During OS, there is aberrant expression of several miRNAs. Among these miRNAs are downregulation of miR-193 that has been associated with cancer occurrence. The aim of the current manuscript is to have overview on the treatment approaches of OS with special focus on miR-193.

Up-regulation of microRNA-497 inhibits the proliferation, migration and invasion but increases the apoptosis of multiple myeloma cells through the MAPK/ERK signaling pathway by targeting Raf-1

Multiple myeloma (MM) is a cancer that occurs in plasma cells, which fall under the category of white blood cells that are in charge of antibody production. According to previous studies, microRNA-497 (miR-497) functions as a tumor suppressor in several types of cancer, including gastric cancer and colorectal cancer. Therefore, the present study aims to investigate the effects of miR-497 on cellular function of human MM cells through the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway by targeting Raf-1. The differentially expressed genes and miRs in MM, and the relationship between the miR and gene were verified. It was found that Raf-1 was a target gene of miR-497. The data obtained from MM tissues showed increased Raf-1 level and decreased miR-497 level. MM cells were treated with mimic, inhibitor and siRNA in order to evaluate the role of miR-497, Raf-1 and MAPK/ERK in MM. The expression pattern of miR-497, Raf-1, ERK1/2, survivin, B-cell lymphoma-2 (Bcl-2) and BCL2-Associated X (Bax) as well as the extent of ERK1/2 phosphorylation were determined. Retored miR-497 and si-Raf-1 resulted in increases in the Bax expression and cell apoptosis and decreases in the expressions of Raf-1, MEK-2, survivin, Bcl-2, along with the extent of ERK1/2 phosphorylation. In addition, the biological function evaluations of MM cells revealed that miR-497 mimic or si-Raf-1 led to suppression in cell proliferation, invasion and migration. In conclusion, our results have demonstrated that miR-497 targets Raf-1 in order to inhibit the progression of MM by blocking the MAPK/ERK signaling pathway.

MicroRNA-497 inhibits multiple myeloma growth and increases susceptibility to bortezomib by targeting Bcl-2

Multiple myeloma (MM) is a common severe hematopoietic malignancy occuring in aged population. MicroRNA (miR)‑497 was previously reported to contribute to the apoptosis of other cell types, presumably through targeting B‑cell lymphoma 2 (Bcl‑2). In the present study, miRNA and protein expression levels were detected by reverse transcription‑quantitative polymerase chain reaction and western blot analyses, respectively. The cell proliferation and viability was measured using 3‑(4,5‑dimethylthiazol‑2‑yl)‑2, 5‑diphenyltetrazolium bromide and plate clonality assays, and the cell growth cycle was measured with a flow cytometer. Terminal deoxynucleotidyl transferase (TdT)‑mediated dUTP nick‑end‑labeling, Annexin V and caspase‑3 activity assays were performed to examine the cell apoptotic rates. The results showed that miR‑497 was markedly decreased, whereas Bcl‑2 was enhanced in MM tissues and cell lines. miR‑497 targeted Bcl‑2 and affected its downstream apoptosis‑related genes. The overexpression of miR‑497 promoted MM cell apoptosis through cell cycle arrest, and decreased colony genesis ability and viability. In addition, miR‑497 increased the sensitivity of MM cells to bortezomib. Taken together, miR‑497 suppressed MM cell proliferation and promoted apoptosis by directly targeting Bcl‑2 and altering the expression of downstream apoptosis‑related proteins. The combination of miR‑497 and bortezomib may enhance drug sensitivity, serving as a potentially available therapeutic method for MM.

Role of miR-142 in the pathogenesis of osteosarcoma and its potential as therapeutic approach

Osteosarcoma (OS) is the most common primary malignant tumor of the bone with a strong tendency to early metastasis, and occurs in growing bones more commonly in children and adolescents. Considering the limited therapeutic methods and lack of 100% success of these methods, developing innovative therapies with high efficacy and lower side effects is needed. Meanwhile, miRNAs and the studies indicating the involvement of miRNAs in OS development have attracted attentions as a result of the frequent abnormalities in expression of miRNAs in cancer. miRNAs are noncoding short sequences with lengths ranging from 18 to 25 nucleotides that play a very important role in cellular processes, such as proliferation, differentiation, migration, and apoptosis. MiRNAs can have either oncogenic or tumor suppressive role based on cellular function and targets. This review aimed to have overview on miR-142 as a tumor suppressor in OS. Moreover, the genes involved in the disease, such as RAC1, HMAG1, MMP9, MMP2, and E-cadherin, which have irregularities as a result of change in miR-142 expression, and, thereby, result in increasing the proliferation, invasion, and metastasis of the cells in the tissues and OS cells will be discussed.

Association between miR-124-1 rs531564 polymorphism and risk of cancer: An updated meta-analysis of case-control studies

Many studies examined the association between miR-124-1 rs531564 polymorphism and the risk of some human cancers, but the findings remain controversial. This update meta-analysis aimed to validate the association between rs531564 polymorphism of miR-124-1 and cancer risk. Eligible studies including 6,502 cancer cases and 7,213 controls were documented by searching Web of Science, PubMed, Scopus, and Google scholar databases. Pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were estimated to quantitatively evaluate the association between rs531564 variant and cancer risk. The results indicated that rs531564 variant significantly decreased the risk of cancer in homozygous codominant (OR=0.54, 95 % CI=0.43-0.69, p<0.00001, GG vs CC), dominant (OR=0.84, 95 % CI=0.72-0.99, p=0.03, CG+GG vs CC), recessive (OR=0.65, 95 % CI=0.54-0.78, p<0.00001, GG vs CG+CC), and allele (OR=0.84, 95 % CI=0.73-0.96, p=0.008, G vs C) genetic model. Stratified analysis by cancer type revealed that rs531564 variant was associated with gastric cancer, cervical cancer, esophageal squamous cell carcinoma and colorectal cancer risk. In summary, the findings of this meta-analysis support an association between miR-124-1 rs531564 polymorphism and cancer risk. Larger and well-designed studies are required to estimate this association in detail.

Ellagic acid and Sennoside B inhibit osteosarcoma cell migration, invasion and growth by repressing the expression of c-Jun

Osteosarcoma is a mesenchymally derived, high-grade bone sarcoma that is the most frequently diagnosed primary malignant bone tumor. Today, chemoprevention is regarded as a promising and realistic approach in the prevention of human cancer. Previous studies have suggested ellagic acid (EA) and Sennoside B have potential in this regard. The aim of the present study was to elucidate the anti-osteosarcoma effects of EA and Sennoside B by using Saos-2 and MG63 osteosarcoma cells. It was identified that EA or Sennoside B treatment could inhibit the growth, migration and invasion of the cells, and induce G₁ cell cycle arrest by repressing the transcription of c-Jun. These results may provide a cellular basis for the application of EA or Sennoside B in the treatment of patients with osteosarcoma.

Circulating microRNAs as potential cancer biomarkers: the advantage and disadvantage

MicroRNAs are endogenous single-stranded non-coding small RNA molecules that can be secreted into the circulation and exist stably. They usually exhibit aberrant expression under different physiological and pathological conditions. Recently, differentially expressed circulating microRNAs were focused on as potential biomarkers for cancer screening. We herein review the role of circulating microRNAs for cancer diagnosis, tumor subtype classification, chemo- or radio-resistance monitoring, and outcome prognosis. Moreover, circulating microRNAs still have several issues hindering their reliability for the practical clinical application. Future studies need to elucidate further potential application of circulating microRNAs as specific and sensitive markers for clinical diagnosis or prognosis in cancers.

MicroRNAs for osteosarcoma in the mouse: a meta-analysis

Osteosarcoma (OS) is the most common primary malignant bone carcinoma with high morbidity that happens mainly in children and young adults. As the key components of gene-regulatory networks, microRNAs (miRNAs) control many critical pathophysiological processes, including initiation and progression of cancers. The objective of this study is to summarize and evaluate the potential of miRNAs as targets for prevention and treatment of OS in mouse models, and to explore the methodological quality of current studies. We searched PubMed, Web of Science, Embase, Wan Fang Database, VIP Database, China Knowledge Resource Integrated Database, and Chinese BioMedical since their beginning date to 10 May 2016. Two reviewers separately screened the controlled studies, which estimate the effects of miRNAs on osteosarcoma in mice. A pair-wise analysis was performed. Thirty six studies with enough randomization were selected and included in the meta-analysis. We found that blocking oncogenic or restoring decreased miRNAs in cancer cells could significantly suppress the progression of OS in vivo, as assessed by tumor volume and tumor weight. This meta-analysis suggests that miRNAs are potential therapeutic targets for OS and correction of the altered expression of miRNAs significantly suppresses the progression of OS in mouse models, however, the overall methodological quality of studies included here was low, and more animal studies with the rigourous design must be carried out before a miRNA-based treatment could be translated from animal studies to clinical trials.

MicroRNA-124-3p directly targets PDCD6 to inhibit metastasis in breast cancer

Breast cancer (BC) is the leading cause of cancer-associated mortality among women worldwide, with a poor 5-year survival rate, particularly among patients with metastatic BC. Previous studies have indicated that the dysregulation of microRNAs (miRNAs/miRs) is associated with carcinogenesis and metastasis. Thus, investigating the underlying molecular mechanisms by which miRNAs mediate their effects may aid in the improvement of BC treatment. In the present study, reverse transcription-quantitative polymerase chain reaction analyses were performed to investigate miR-124-3p expression in BC tissues. The expression of miR-124-3p was significantly decreased in primary BC tissues compared with that in adjacent non-tumor tissues. Downregulated miR-124-3p was correlated with lymph node metastasis and a low overall survival time. Wound-healing and Transwell assays revealed that MDA-MB-231 and MCF-7 cell motility was inhibited by miR-124-3p, but was promoted by a miR-124-3p inhibitor. Overexpression of miR-124-3p increased levels of E-cadherin, and decreased levels of N-cadherin and Vimentin, indicating that miR-124-3p inhibits the epithelial-mesenchymal transition. In addition, a bioinformatics analysis and subsequent in vitro experiments identified programmed cell death protein 6 (PDCD6) as a direct target of miR-124-3p. Restoration of PDCD6 expression impaired the metastasis inhibitor role of miR-124-3p by promoting cell invasion. Furthermore, the expression of miR-124-3p was inversely associated with PDCD6 mRNA levels in clinical breast tumors. Taken together, these data suggest that miR-124-3p inhibits tumor metastasis by inhibiting PDCD6 expression, and that the miR-124-3p/PDCD6 signaling axis may be a potential target for novel treatments in patients with advanced BC.

NOVA1 acts as an oncogene in osteosarcoma

Osteosarcoma is one of the most common bone tumors in young patients. NOVA1 (neuro-oncological ventral antigen 1) is a neuron-specific RNA binding-protein and belongs to the Nova family. Previous studies showed that NOVA1 played crucial roles in the development of several tumors. The objective of our study was to study the role of NOVA1 in the osteosarcoma. In our study, we showed that NOVA1 expression was upregulated in osteosarcoma cell lines and tissues. The expression of NOVA1 was upregulated in 22 (22/30; 73%) osteosarcoma cases compared to that in the adjacent tissues. Overexpression of NOVA1 promoted osteosarcoma cell viability, colony formation and invasion. Furthermore, knockdown of NOVA1 suppressed osteosarcoma cell viability, colony formation and invasion. These data suggested that NOVA1 acted as an oncogene in the development of osteosarcoma.

MicroRNA‑497 inhibits cellular proliferation, migration and invasion of papillary thyroid cancer by directly targeting AKT3

Thyroid cancer is the most common tumor of the endocrine organs. Emerging studies have indicated the critical roles of microRNAs (miRs) in papillary thyroid cancer (PTC) formation and progression through function as tumor suppressors or oncogenes. The present study investigated the expression level and biological roles of miR-497 in PTC and its underlying mechanisms. It was demonstrated that the expression level of miR-497 was reduced in both PTC tissues and cell lines. Enforced expression of miR-497 suppressed PTC cell proliferation, migration and invasion. According to bioinformatics analysis, a luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction and western blotting, RAC-γ serine/threonine-protein kinase (AKT3) was demonstrated to be the direct target gene of miR-497. In addition, AKT3 expression increased in PTC tissues and negatively correlated with miR-497 expression. Furthermore, downregulation of AKT3 also suppressed cell proliferation, migration and invasion of PTC, which had similar roles to miR-497 overexpression in PTC cells. Taken together, these results suggested that this newly identified miR-497/AKT3 signaling pathway may contribute to PTC occurrence and progression. These findings provide novel potential therapeutic targets for the therapy of PTC.

MicroRNA‑643 regulates the expression of ZEB1 and inhibits tumorigenesis in osteosarcoma

Osteosarcoma is among the most malignant types of tumor worldwide and has become a leading contributor to tumor incidence, particularly in adolescents. Resistance to conventional treatment and the complexity of osteosarcoma tumorigenesis has resulted in high mortality rates. MicroRNAs are a class of noncoding RNAs, which regulate numerous biological processes. However, the involvement of miR‑643 in osteosarcoma remains to be elucidated. In the present study, reverse transcription‑quantitative polymerase chain reaction, luciferase reporter assay, invasion assay, viability assay, western blot analysis and in vivo implantation were performed to analyze the action of miR‑643 in osteosarcoma. The results demonstrated that miR‑643 inhibited the progression of osteosarcoma and acted as a potential tumor suppressor. The expression of miR‑643 was downregulated in osteosarcoma tissues and cell lines. In addition, miR‑643 transfection significantly impaired the proliferation and invasion of osteosarcoma cells. The present study also identified Zinc finger E‑box‑binding homeobox 1 (ZEB1) as a direct target of miR‑643, and the ectopic expression of ZEB1 counteracted the effect of miR‑643 transfection. A significant inverse correlation was also found between the expression of miR‑643 and ZEB1. A low expression of miR‑643 or a high expression of ZEB1 was associated with poor patient survival rates. The results of the present study suggested that the decreased expression of miR‑643 may be involved in the mechanism underlying the development of osteosarcoma. The intricate interactions between miR‑643 and ZEB1 may serve as a potential therapeutic target in osteosarcoma oncogenesis.

What Is New in the miRNA World Regarding Osteosarcoma and Chondrosarcoma?

Despite the availability of multimodal and aggressive therapies, currently patients with skeletal sarcomas, including osteosarcoma and chondrosarcoma, often have a poor prognosis. In recent decades, advances in sequencing technology have revealed the presence of RNAs without coding potential known as non-coding RNAs (ncRNAs), which provides evidence that protein-coding genes account for only a small percentage of the entire genome. This has suggested the influence of ncRNAs during development, apoptosis and cell proliferation. The discovery of microRNAs (miRNAs) in 1993 underscored the importance of these molecules in pathological diseases such as cancer. Increasing interest in this field has allowed researchers to study the role of miRNAs in cancer progression. Regarding skeletal sarcomas, the research surrounding which miRNAs are involved in the tumourigenesis of osteosarcoma and chondrosarcoma has rapidly gained traction, including the identification of which miRNAs act as tumour suppressors and which act as oncogenes. In this review, we will summarize what is new regarding the roles of miRNAs in chondrosarcoma as well as the latest discoveries of identified miRNAs in osteosarcoma.

Single nucleotide polymorphism of hsa-miR-124a affects risk and prognosis of osteosarcoma

OBJECTIVE

To study the correlation between single nucleotide polymorphism (SNP) of hsa-miR-124a and risk and prognosis of osteosarcoma (OS).

METHODS

OS patients (n = 174) hospitalized at The Second Affiliated Hospital of Harbin Medical University from January 2010 to March 2012 were selected as case group by inclusion and exclusion criteria, and healthy people (n = 150) receiving physical examination at the same duration were recruited as control group. Polymerase chain reaction-ligase detection reaction (PCR-LDR) was performed for genotyping of hsa-miR-124a rs531564.

RESULTS

There were significant differences in the frequency distribution of genotypes and alleles of hsa-miR-124a rs531564 in the case and control group (all P < 0.05); the individuals carrying with CG + GG genotype showed significantly decreased risk for OS. The clinical pathological characteristics were significantly different in the patients with CC genotype and CG + GG genotype, including tumor size, tumor differentiation grading, Enneking staging, operation manner, time of chemotherapy and metastasis (all P < 0.05). The 5-year survival rate of the cases with CC genotype was significantly lower than that of the ones with CG + GG genotype (P < 0.05). CG + GG genotype, Enneking staging and operation manner were independent risk factors for prognosis of OS (all P < 0.05).

CONCLUSIONS

CG +$ GG genotype of hsa-miR-124a rs531564 had decreased risk for OS and affected prognosis of OS.

MicroRNA-497 Inhibits Cardiac Hypertrophy by Targeting Sirt4

Cardiac hypertrophy is an adaptive enlargement of the myocardium in response to overload pressure of heart. From abundant studies, a conclusion is drawn that many microRNAs (miRNAs) are associated with cardiac hypertrophy and heart failure. To investigate the role of microRNA-497 (miR-497) in myocardial hypertrophy, two models were established in this study from cell level to integral level. Cardiac hypertrophy was induced by using angiotensin Ⅱ (Ang Ⅱ) in vitro and was created by transverse abdominal aortic constriction (TAC) in vivo. There was a significant decrease expression of miR-497 in cardiac hypertrophy models. Moreover, overexpression of miR-497 inhibited myocardial hypertrophy both in vitro and in vivo without heart function variation. In addition, luciferase reporter assays demonstrated that Sirt4 was a direct target gene of miR-497. Taking together, our study indicates that miR-497 modulates cardiac hypertrophy by targeting Sirt4 and may serve as a potential therapeutic substance in the course.

MicroRNA-497 suppresses cell proliferation and induces apoptosis through targeting PBX3 in human multiple myeloma

Aberrant expression of microRNA-497 (miRN-497) is implicated in development and progression of multiple types of cancers. However, the biological function and underlying mechanism of miR-497 in multiple myeloma (MM) remains unclear. Thus, we studied the potential biological roles of miR-497 in MM. The expression of miR-497 was examined in multiple myeloma and normal plasma cells by qRT-PCR. Biological functions of miR-497 were analyzed using cell proliferation, colony formation, cell cycle, apoptosis and luciferase assays in vitro, as well as via tumorigenicity in vivo analysis. Here, we observed reduced expression of miR-497 in MM plasma samples and cell lines. Ectopic expression of miR-497 dramatically suppressed cell proliferation and clonogenicity, as well as induced cell arrest at G0/G1 stage and apoptosis in vitro. Mechanistic investigation assays showed that Pre-B-cellleukemia transcription factor 3 (PBX3) was a novel and direct downstream target of miR-497. Interestingly, overexpression of PBX3 partially reverted the effect of miR-497 in MM cells. In xenograft model, overexpression of miR-497 inhibited tumorigenicity by repressing PBX3. These findings collectively suggested that miR-497 functioned as tumor suppressor in MM by directly targeting PBX3, supporting its utility as a novel and potential therapeutic agent for MM therapy.

A miRNAs panel promotes the proliferation and invasion of colorectal cancer cells by targeting GABBR1

MicroRNAs (miRNAs) have been implicated in the regulation of colorectal cancer. Despite the expression of miR-17-92 cluster in cancer has been gradually revealed, the role of each individual miRNAs in colorectal cancer still remains unclear. We studied the impact of miR-106a/b, miR-20a/b, and miR-17 of miR-17-92 cluster on colorectal cancer cells. Real-time quantitative polymerase chain reactions (RT-PCR) were used to test these five miRNAs expression in colorectal cancer cell line HCT116. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assays, Bromodeoxyuridine (BrdU), and Transwell invasion assays were used to explore the effects of these five miRNAs in colorectal cancer cells. Luciferase reporter assay, RT-PCR, and western blotting were performed to validate the interaction of these five miRNAs with the gamma-amino-butyric acid type B receptor 1(GABBR1). We found that these five miRNAs were significantly upregulated in colorectal cancer samples compared with normal tissues. Forced expression of these five miRNAs significantly promoted HCT116 and HT-29 cells proliferation and invasion. We further found that these five miRNAs function as oncogenes in colorectal cancer by specifically binding to the 3-untranslated regions (3'UTR) of GABBR1.Furthermore, inhibition of GABBR1 could mimic the function of miRNAs in HCT116 cells, while overexpression of GABBR1 blocked the function of miRNAs-promoted proliferation and invasion. In conclusion, miR-106a/b, miR-20a/b, and miR-17 contribute to the proliferation and invasion of colorectal cancer by targeting their common target gene, GABBR1, and played a critical role in the proliferation and invasion of colorectal cancer.