Alteration in the Expression of Circular Rnas and its association with the Development and Progression of Osteosarcoma, an Integrative Review with High Sensitivity Research.

BACKGROUND: Osteosarcoma is the most common primary malignant bone tumor, mainly affecting children, young adults, and the elderly. It is an aggressive cancer with a poor prognosis, exhibiting low survival rates even with standard treatment. Recently, circular RNA molecules capable of influencing gene expression through various functions, with their main role being acting as microRNA sponges and reducing their intracellular expression, have been identified. Recent studies have linked circular RNAs to osteosarcoma development and progression. Therefore, the present study aimed to investigate the alteration in circular RNA expression during osteosarcoma development and progression. METHODS: An integrative literature review was conducted from September 10th to November 12th, 2021, using the following databases: PubMed/MEDLINE, SCOPUS, Web of Science, OVID, and EMBASE. 129 full articles were included in the review. The obtained data were organized using a standardized data collection instrument, which included the following information: altered expression profile of circular RNAs, associated cancer hallmarks, clinical-pathological relationships of circular RNAs, and perspectives on the studied circular RNAs. RESULTS: A total of 94 distinct circular RNAs were identified, predominantly showing an increased expression pattern. Approximately 91% of the studies that aimed to identify the mechanisms of action of circular RNAs highlighted the function of circular RNAs as microRNA sponges. The most associated cancer hallmarks with the identified circular RNAs were proliferative signaling induction, invasion and metastasis, and resistance to cell death. The altered expression of these circular RNAs generally correlated with a worse prognosis for patients, as evidenced by clinical features such as shorter survival, advanced Enneking and/or TNM stage, higher incidence of metastasis, larger tumor size, and increased chemoresistance. CONSLUSION: These findings indicate the significance of circular RNA molecules in osteosarcoma carcinogenesis, suggesting their potential as new prognostic and/or diagnostic biomarkers, as well as alternative therapeutic targets in the fight against osteosarcoma.

DNA methylation profile discriminates sporadic giant cell granulomas of the jaws and cherubism from their giant cell-rich histological mimics.

Sporadic giant cell granulomas (GCGs) of the jaws and cherubism-associated giant cell lesions share histopathological features and microscopic diagnosis alone can be challenging. Additionally, GCG can morphologically closely resemble other giant cell-rich lesions, including non-ossifying fibroma (NOF), aneurysmal bone cyst (ABC), giant cell tumour of bone (GCTB), and chondroblastoma. The epigenetic basis of these giant cell-rich tumours is unclear and DNA methylation profiling has been shown to be clinically useful for the diagnosis of other tumour types. Therefore, we aimed to assess the DNA methylation profile of central and peripheral sporadic GCG and cherubism to test whether DNA methylation patterns can help to distinguish them. Additionally, we compared the DNA methylation profile of these lesions with those of other giant cell-rich mimics to investigate if the microscopic similarities extend to the epigenetic level. DNA methylation analysis was performed for central (n = 10) and peripheral (n = 10) GCG, cherubism (n = 6), NOF (n = 10), ABC (n = 16), GCTB (n = 9), and chondroblastoma (n = 10) using the Infinium Human Methylation EPIC Chip. Central and peripheral sporadic GCG and cherubism share a related DNA methylation pattern, with those of peripheral GCG and cherubism appearing slightly distinct, while central GCG shows overlap with both of the former. NOF, ABC, GCTB, and chondroblastoma, on the other hand, have distinct methylation patterns. The global and enhancer-associated CpG DNA methylation values showed a similar distribution pattern among central and peripheral GCG and cherubism, with cherubism showing the lowest and peripheral GCG having the highest median values. By contrast, promoter regions showed a different methylation distribution pattern, with cherubism showing the highest median values. In conclusion, DNA methylation profiling is currently not capable of clearly distinguishing sporadic and cherubism-associated giant cell lesions. Conversely, it could discriminate sporadic GCG of the jaws from their giant cell-rich mimics (NOF, ABC, GCTB, and chondroblastoma).

Analysis of the Mutational Landscape of Osteosarcomas Identifies Genes Related to Metastasis and Prognosis and Disrupted Biological Pathways of Immune Response and Bone Development.

Osteosarcoma (OS) is the most prevalent type of bone tumor, but slow progress has been achieved in disentangling the full set of genomic events involved in its initiation and progression. We assessed by NGS the mutational spectrum of 28 primary OSs from Brazilian patients, and identified 445 potentially deleterious SNVs/indels and 1176 copy number alterations (CNAs). TP53 was the most recurrently mutated gene, with an overall rate of ~60%, considering SNVs/indels and CNAs. The most frequent CNAs (~60%) were gains at 1q21.2q21.3, 6p21.1, and 8q13.3q24.22, and losses at 10q26 and 13q14.3q21.1. Seven cases presented CNA patterns reminiscent of complex events (chromothripsis and chromoanasynthesis). Putative RB1 and TP53 germline variants were found in five samples associated with metastasis at diagnosis along with complex genomic patterns of CNAs. PTPRQ, KNL1, ZFHX4, and DMD alterations were prevalent in metastatic or deceased patients, being potentially indicative of poor prognosis. TNFRSF11B, involved in skeletal system development and maintenance, emerged as a candidate for osteosarcomagenesis due to its biological function and a high frequency of copy number gains. A protein-protein network enrichment highlighted biological pathways involved in immunity and bone development. Our findings reinforced the high genomic OS instability and heterogeneity, and led to the identification of novel disrupted genes deserving further evaluation as biomarkers due to their association with poor outcomes.

Development of a novel vasculogenic mimicry-associated gene signature for the prognostic assessment of osteosarcoma patients.

BACKGROUND: Osteosarcoma (OS) is a form of primary bone malignancy associated with poor prognostic outcomes. Recent work has highlighted vasculogenic mimicry (VM) as a key mechanism that supports aggressive tumor growth. The patterns of VM-associated gene expression in OS and the relationship between these genes and patient outcomes, however, have yet to be defined. METHODS: Here, 48 VM-related genes were systematically assessed to examine correlations between the expression of these genes and OS patient prognosis in the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) cohort. Patients were classified into three OS subtypes. Differentially expressed genes for these three OS subtypes were then compared with hub genes detected in a weighted gene co-expression network analysis, leading to the identification of 163 overlapping genes that were subject to further biological activity analyses. A three-gene signature (CGREF1, CORT, and GALNT14) was ultimately constructed through a least absolute shrinkage and selection operator Cox regression analysis, and this signature was used to separate patients into low- and high-risk groups. The K-M survival analysis, receiver operating characteristic analysis, and decision curve analysis were adopted to evaluate the prognostic prediction performance of the signature. Furthermore, the expression patterns of three genes derived from the prognostic model were validated by quantitative real-time polymerase chain reaction (RT-qPCR). RESULTS: VM-associated gene expression patterns were successfully established, and three VM subtypes of OS that were associated with patient prognosis and copy number variants were defined. The developed three-gene signature was constructed, which served as independent prognostic markers and prediction factors for the clinicopathological features of OS. Finally, lastly, the signature may also have a guiding effect on the sensitivity of different chemotherapeutic drugs. CONCLUSION: Overall, these analyses facilitated the development of a prognostic VM-associated gene signature capable of predicting OS patient outcomes. This signature may be of value for both studies of the mechanistic basis for VM and clinical decision-making in the context of OS patient management.

DNA methylation patterns suggest the involvement of DNMT3B and TET1 in osteosarcoma development.

DNA methylation may be involved in the development of osteosarcomas. Osteosarcomas commonly arise during the bone growth and remodeling in puberty, making it plausible to infer the involvement of epigenetic alterations in their development. As a highly studied epigenetic mechanism, we investigated DNA methylation and related genetic variants in 28 primary osteosarcomas aiming to identify deregulated driver alterations. Methylation and genomic data were obtained using the Illumina HM450K beadchips and the TruSight One sequencing panel, respectively. Aberrant DNA methylation was spread throughout the osteosarcomas genomes. We identified 3146 differentially methylated CpGs comparing osteosarcomas and bone tissue samples, with high methylation heterogeneity, global hypomethylation and focal hypermethylation at CpG islands. Differentially methylated regions (DMR) were detected in 585 loci (319 hypomethylated and 266 hypermethylated), mapped to the promoter regions of 350 genes. These DMR genes were enriched for biological processes related to skeletal system morphogenesis, proliferation, inflammatory response, and signal transduction. Both methylation and expression data were validated in independent groups of cases. Six tumor suppressor genes harbored deletions or promoter hypermethylation (DLEC1, GJB2, HIC1, MIR149, PAX6, and WNT5A), and four oncogenes presented gains or hypomethylation (ASPSCR1, NOTCH4, PRDM16, and RUNX3). Our analysis also revealed hypomethylation at 6p22, a region that contains several histone genes. Copy-number changes in DNMT3B (gain) and TET1 (loss), as well as overexpression of DNMT3B in osteosarcomas provide a possible explanation for the observed phenotype of CpG island hypermethylation. While the detected open-sea hypomethylation likely contributes to the well-known osteosarcoma genomic instability, enriched CpG island hypermethylation suggests an underlying mechanism possibly driven by overexpression of DNMT3B likely resulting in silencing of tumor suppressors and DNA repair genes.

Quantitative expression evaluation of PRAME gene in osteosarcoma.

BACKGROUND: In a previous study, our group observed that 68% of the osteosarcoma (OS) samples presented PRAME (Preferentially Expressed Antigen in Melanoma) gene expression. In this work, we propose to investigate quantitatively gene expression of PRAME in distinct patients groups. METHODS AND RESULTS: 61 osteosarcoma samples, from 3 distinct patients groups were selected for this study: (1) Patients younger than 10 years old at diagnosis, (2) Patients that had poor evolution of disease and (3) Patients that were in remission of disease and had treatment with no intercurrences) PRAME gene expression levels were obtained using quantitative Real-Time Polymerase Chain Reaction method (qRT-PCR). Clinical parameters were collected from patient's medical charts. Results demonstrated an increase in PRAME gene expression in all samples, with high variation in expression levels, when considering all samples and when analyzed in each group. In addition, no statistical difference was found when considering clinical data collected or patients groups. CONCLUSION: PRAME gene expression quantitative investigation did not bring any complementary information beyond of what had already been observed in other qualitative investigations published by our group, there is no relation between PRAME gene expression levels and disease evolution. However, the findings in this work contribute for validation PRAME gene expression as a good biomarker to OS, which, in the future, may allow identification circulating tumor cell or molecules to contribute with early diagnostic of metastasis, a genuine problem in OS that determinate flattening in survival curves.

Pharmacogenetics of the Primary and Metastatic Osteosarcoma: Gene Expression Profile Associated with Outcome.

Osteosarcoma (OS) is the most common malignant bone tumor in children and adolescents. In recent decades, OS treatment has reached a plateau and drug resistance is still a major challenge. Therefore, the present study aimed to analyze the expression of the genes related to pharmacogenetics in OS. The expression of 32 target genes in 80 paired specimens (pre-chemotherapeutic primary tumor, post-chemotherapeutic primary tumor and pulmonary metastasis) obtained from 33 patients diagnosed with OS were analyzed by the real-time PCR methodology. As the calibrators (control), five normal bone specimens were used. The present study identified associations between the OS outcome and the expression of the genes TOP2A, DHFR, MTHFR, BCL2L1, CASP3, FASLG, GSTM3, SOD1, ABCC1, ABCC2, ABCC3, ABCC5, ABCC6, ABCC10, ABCC11, ABCG2, RALBP1, SLC19A1, SLC22A1, ERCC1 and MSH2. In addition, the expression of the ABCC10, GGH, GSTM3 and SLC22A1 genes were associated with the disease event, and the metastasis specimens showed a high expression profile of ABCC1, ABCC3 and ABCC4 genes and a low expression of SLC22A1 and ABCC10 genes, which is possibly an important factor for resistance in OS metastasis. Therefore, our findings may, in the future, contribute to clinical management as prognostic factors as well as possible therapeutic targets.

TIPE1 inhibits the growth of Ewing's sarcoma cells by suppressing Wnt/ß-catenin signaling.

BACKGROUND: Ewing's sarcoma is the second most common bone and soft tissue malignancy in children and adolescents. Tumor necrosis factor-α-induced protein 8-like 1 (TIPE1) functions as a tumor suppressor in several cancers. Activation of Wnt/ß-catenin signaling in subpopulations of tumor cells contributes to phenotypic heterogeneity and disease progression in Ewing's sarcoma. The exact role of TIPE1 in Ewing's sarcoma remains to be elucidated. PURPOSE: This study aimed to assess the expression and function of TIPE1 in Ewing's sarcoma. METHODS: TIPE1 expression in Ewing's sarcoma cells was determined by qPCR and western blotting. Furthermore, the Ewing's sarcoma cell line RD-ES was transfected with a lentivirus-based TIPE1 expression system to upregulate the expression of TIPE1. The Cell Counting Kit 8 was used to assess the effect of TIPE1 on cell proliferation. The effects of TIPE1 on cell migration and invasion was detected by Transwell assay. Flow cytometry was performed to detect apoptosis. RESULTS: Our results suggested lower TIPE1 expression in Ewing's sarcoma cell lines compared with normal osseous cells. TIPE1 remarkably inhibited the growth and proliferation of Ewing's sarcoma cell; TIPE1 also induced apoptosis and inhibited invasion in vitro. TIPE1 inhibited Ewing's sarcoma growth, motility, and survival through regulation of Wnt/ß-catenin signaling. CONCLUSIONS: Our results demonstrated the anti-tumor function of TIPE1 in Ewing's sarcoma and reveal a novel therapeutic target.

Rare Association Between Osteogenesis Imperfecta and Chondrosarcoma: Could a Pathogenic Variant in the Gene SERPINF1 Explain It?

Osteogenesis imperfecta (OI) type VI is a rare inherited disorder of the connective tissue caused by pathogenic variants in SERPINF1 gene, which encodes the pigment epithelium-derived factor (PEDF). PEDF is implicated in many biologic processes, including an anti-cancer role. This information is supported by in vitro and in vivo studies that evidenced its anti-angiogenic, anti-tumorigenic, and anti-metastatic properties. Although OI is related to skeletal changes such as bone fragility and deformities, as well as to other connective tissue defects, it does not represent a greater predisposition to the development of skeletal tumors. Here, we report on an adult with OI in which a deletion in exon 8 of the SERPINF1 gene (c.1152_1170del; p.384_390del) was identified. The patient presented popcorn calcification in both femoral epiphyses, but one of them presented radiological characteristics and evolution suspected of malignancy. Later, it was diagnosed as chondrosarcoma. This paper discusses that OI type VI patients may be at risk of developing some types of cancer.

IL-1ß expression driven by androgen receptor absence or inactivation promotes prostate cancer bone metastasis.

We report the inverse association between the expression of androgen receptor (AR) and interleukin-1beta (IL-1ß) in a cohort of patients with metastatic castration resistant prostate cancer (mCRPC). We also discovered that AR represses the IL-1ß gene by binding an androgen response element (ARE) half-site located within the promoter, which explains the IL-1ß expression in AR-negative (ARNEG) cancer cells. Consistently, androgen-depletion or AR-pathway inhibitors (ARIs) de-repressed IL-1ß in ARPOS cancer cells, both in vitro and in vivo. The AR transcriptional repression is sustained by histone de-acetylation at the H3K27 mark in the IL-1ß promoter. Notably, patients' data suggest that DNA methylation prevents IL-1ß expression, even if the AR-signaling axis is inactive. Our previous studies show that secreted IL-1ß supports metastatic progression in mice by altering the transcriptome of tumor-associated bone stroma. Thus, in prostate cancer patients harboring ARNEG tumor cells or treated with ADT/ARIs, and with the IL-1ß gene unmethylated, IL-1ß could condition the metastatic microenvironment to sustain disease progression.

BRCA1-associated RING domain-1 (BARD1) loss and GBP1 expression enhance sensitivity to DNA damage in Ewing sarcoma.

Ewing sarcoma is a fusion oncoprotein-driven primary bone tumor. A subset of patients (~10%) with Ewing sarcoma are known to harbor germline variants in a growing number of genes involved in DNA damage repair. We recently reported our discovery of a germline mutation in the DNA damage repair protein BARD1 (BRCA1-associated RING domain-1) in a patient with Ewing sarcoma. BARD1 is recruited to the site of DNA double stranded breaks via the poly(ADP-ribose) polymerase (PARP) protein and plays a critical role in DNA damage response pathways including homologous recombination. We thus questioned the impact of BARD1 loss on Ewing cell sensitivity to DNA damage and the Ewing sarcoma transcriptome. We demonstrate that PSaRC318 cells, a novel patient-derived cell line harboring a pathogenic BARD1 variant, are sensitive to PARP inhibition and by testing the effect of BARD1 depletion in additional Ewing sarcoma cell lines, we confirm that BARD1 loss enhances cell sensitivity to PARP inhibition plus radiation. Additionally, RNA-seq analysis revealed that loss of BARD1 results in the upregulation of GBP1 (guanylate-binding protein 1), a protein whose expression is associated with variable response to therapy depending on the adult carcinoma subtype examined. Here, we demonstrate that GBP1 contributes to the enhanced sensitivity of BARD1 deficient Ewing cells to DNA damage. Together, our findings demonstrate the impact of loss-of function mutations in DNA damage repair genes, such as BARD1, on Ewing sarcoma treatment response.

Periosteal chondrosarcoma: A case series in a referral center with survivorship analysis.

BACKGROUND: Periosteal chondrosarcomas are among the rarest types of chondrosarcomas dealt with in few small series of cases. In this study, we aimed to present our experience with this chondrosarcoma, seek for prognostic factors for OS and DFS and survey the status of IDH1 and IDH2. RESULTS: 55 periosteal chondrosarcomas were retrospectively identified. Median age was 37 years, there was a male predominance (62%). The great majority of cases involved the metaphysis of long bones of the extremities. The median size of the tumors was 7.5 cm. Thirty patients underwent to subtotal surgical resection, 22 to tangential resection and the remaining 3 to amputation. The margins, reported in 54 cases, were wide/radical in 38 patients (70.4%), marginal in 9 (16.7%) and intralesional in 7 (12.9%). Histologically, 23 (42%) were grade 1; 27 (49%), grade 2; 3 (5%), grade 3 and 2 (4%) were dedifferentiated. A third of cases in which mutational analysis was feasible harbored heterozygous mutations in codon 132 of IDH1. Fifty-four cases were included for follow-up (median, 137 months). Four patients had local recurrences and six patients developed metastasis to the lungs. All patients that developed metastasis died of disease, two died of unrelated causes and 46 were alive without disease. OS and DFS was not found to be statistically associated with clinical and pathological parameters considered. CONCLUSIONS: periosteal chondrosarcomas exhibit a low-grade behavior that can be adequately treated with marginal excisions. Clinical and morphologic parameters do not seem to predict their outcome.

Molecular profiling of osteosarcoma in children and adolescents from different age groups using a next-generation sequencing panel.

Osteosarcoma (OS) is a malignant bone tumor, with a peak of incidence in the second decade of life and possibly associated with the presence of germline mutations. Besides, clinicians have pointed to a second, rarer group of patients that develops OS before 10 years old. Here we access, through next-generation sequencing (NGS) strategy, the genetic alterations present in OS and blood samples from patients diagnosed before and during the second decade of life. A custom NGS panel, designed for the main alterations described in childhood and adolescence neoplasms, named Oncomine Childhood Cancer Research Assay (OCCRA©), was used. Of all 84 OS samples investigated, 42 (50%) presented some somatic variant, with TP53, MYC, CDK4, RB1 and PDGFRA genes harboring the most observed genetic variants. MYC CNVs were more frequent in tumors from patients diagnosed before 10 years old (X21= 5.18, p = 0.023). Additionally, patients diagnosed during the second decade of life presented a higher percentage of somatic and germline variants. Germline variants in TP53 and RB1 were found in 5 of the 11 (45.5%) patients analyzed. Clinical variables and tumor histopathological characteristics were also collected and correlated with our molecular findings.

Biphasic α2ß1 Integrin Expression in Breast Cancer Metastasis to Bone.

Integrins participate in the pathogenesis and progression of tumors at many stages during the metastatic cascade. However, current evidence for the role of integrins in breast cancer progression is contradictory and seems to be dependent on tumor stage, differentiation status, and microenvironmental influences. While some studies suggest that loss of α2ß1 enhances cancer metastasis, other studies suggest that this integrin is pro-tumorigenic. However, few studies have looked at α2ß1 in the context of bone metastasis. In this study, we aimed to understand the role of α2ß1 integrin in breast cancer metastasis to bone. To address this, we utilized in vivo models of breast cancer metastasis to bone using MDA-MB-231 cells transfected with an α2 expression plasmid (MDA-OEα2). MDA cells overexpressing the α2 integrin subunit had increased primary tumor growth and dissemination to bone but had no change in tumor establishment and bone destruction. Further in vitro analysis revealed that tumors in the bone have decreased α2ß1 expression and increased osteolytic signaling compared to primary tumors. Taken together, these data suggest an inverse correlation between α2ß1 expression and bone-metastatic potential. Inhibiting α2ß1 expression may be beneficial to limit the expansion of primary tumors but could be harmful once tumors have established in bone.

Oncogenic functions of ZEB1 in pediatric solid cancers: interplays with microRNAs and long noncoding RNAs.

The transcription factor Zinc finger E-box binding 1 (ZEB1) displays a range of regulatory activities in cell function and embryonic development, including driving epithelial-mesenchymal transition. Several aspects of ZEB1 function can be regulated by its functional interactions with noncoding RNA types, namely microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). Increasing evidence indicates that ZEB1 importantly influences cancer initiation, tumor progression, metastasis, and resistance to treatment. Cancer is the main disease-related cause of death in children and adolescents. Although the role of ZEB1 in pediatric cancer is still poorly understood, emerging findings have shown that it is expressed and regulates childhood solid tumors including osteosarcoma, retinoblastoma, neuroblastoma, and central nervous system tumors. Here, we review the evidence supporting a role for ZEB1, and its interplays with miRNAs and lncRNAs, in pediatric cancers.

Up-regulation of pro-angiogenic molecules and events does not relate with an angiogenic switch in metastatic osteosarcoma cells but to cell survival features.

Osteosarcoma (OS) is the most frequent malignant bone tumor, affecting predominantly children. Metastases represent a major clinical challenge and an estimated 80% would present undetectable micrometastases at diagnosis. The identification of metastatic traits and molecules would impact in micrometastasis management. We demonstrated that OS LM7 metastatic cells secretome was able to induce microvascular endothelium cell rearrangements, an angiogenic-related trait. A proteomic analysis indicated a gain in angiogenic-related pathways in these cells, as compared to their parental-non-metastatic OS SAOS2 cells counterpart. Further, factors with proangiogenic functions like VEGF and PDGF were upregulated in LM7 cells. However, no differential angiogenic response was induced by LM7 cells in vivo. Regulation of the Fas-FasL axis is key for OS cells to colonize the lungs in this model. Analysis of the proteomic data with emphasis in apoptosis pathways and related processes revealed that the percentage of genes associated with those, presented similar levels in SAOS2 and LM7 cells. Further, the balance of expression levels of proteins with pro- and antiapoptotic functions in both cell types was subtle. Interestingly and of relevance to the model, Fas associated Factor 1 (FAF1), which participates in Fas signaling, was present in LM7 cells and was not detected in SAOS2 cells. The subtle differences in apoptosis-related events and molecules, together with the reported cell-survival functions of the identified angiogenic factors and the increased survival features that we observed in LM7 cells, suggest that the gain in angiogenesis-related pathways in metastatic OS cells would relate to a prosurvival switch rather to an angiogenic switch as an advantage feature to colonize the lungs. OS metastatic cells also displayed higher adhesion towards microvascular endothelium cells suggesting an advantage for tissue colonization. A gain in angiogenesis pathways and molecules does not result in major angiogenic potential. Together, our results suggest that metastatic OS cells would elicit signaling associated to a prosurvival phenotype, allowing homing into the hostile site for metastasis. During the gain of metastatic traits process, cell populations displaying higher adhesive ability to microvascular endothelium, negative regulation of the Fas-FasL axis in the lung parenchyma and a prosurvival switch, would be selected. This opens a new scenario where antiangiogenic treatments would affect cell survival rather than angiogenesis, and provides a molecular panel of expression that may help in distinguishing OS cells with different metastatic potential.

MicroRNA-629-5p promotes osteosarcoma proliferation and migration by targeting caveolin 1.

Osteosarcoma is a highly malignant tumor that occurs in the bone. Previous studies have shown that multiple microRNAs (miRNAs) regulate the development of osteosarcoma. This study aimed to explore the role of miR-629-5p and its target gene, caveolin 1 (CAV1), in osteosarcoma development. To analyze the expression of miR-629-5p and CAV1 mRNA in osteosarcoma tissues and cell lines, qRT-PCR analysis was performed. Dual-luciferase reporter experiments were subsequently performed to validate the relationship between CAV1 and miR-629-5p. CCK8 assay was used to measure osteosarcoma cell proliferation, and wound-healing assay was performed to study their migratory phenotype. Our findings revealed that miR-629-5p was overexpressed in osteosarcoma tissues and cells, and thereby enhanced cell proliferation and migration. Further, we validated that miR-629-5p targets CAV1 mRNA directly. CAV1 expression, which was negatively correlated with miR-629-5p expression, was found to be downregulated in osteosarcoma tissue samples. Moreover, our data showed that an increase in CAV1 level led to a decline in osteosarcoma cell proliferation and migration, which could be rescued by miR-629-5p upregulation. Overall, our study confirmed that miR-629-5p promoted osteosarcoma proliferation and migration by directly inhibiting CAV1.

Long Non-coding RNAs in Cisplatin Resistance in Osteosarcoma.

OPINION STATEMENT: Osteosarcoma (OS), the most common primary malignant bone tumor, is a vastly aggressive disease in children and adolescents. Although dramatic progress in therapeutic strategies have achieved over the past several decades, the outcome remains poor for most patients with metastatic or recurrent OS. Nowadays, conventional treatment for OS patients is surgery combined with multidrug chemotherapy including doxorubicin, methotrexate, and cisplatin (CDDP). In this sense, cisplatin (CDDP) is one of the most drugs used in the treatment of OS but drug resistance to CDDP appears as a serious problem in the use of this drug in the treatment of OS. Thus, we consider that the understanding the molecular mechanisms and the genes involved that lead to CDDP resistance is essential to developing more effective treatments against OS. In this review, we present an outline of the key role of the long non-coding RNAs (lncRNAs) in CDDP resistance in OS. This overview is expected to contribute to understand the mechanisms of CDDP resistance in OS and the relationship of the expression regulation of several lncRNAs.

Down-regulation of HCP5 inhibits cell proliferation, migration, and invasion through regulating EPHA7 by competitively binding miR-101 in osteosarcoma.

Patients with osteosarcoma (OS) usually have poor overall survival because of frequent metastasis. Long non-coding RNAs (lncRNAs) have been reported to be associated with tumorigenesis and metastasis. In this study, we investigated the expression and roles of lncRNA human histocompatibility leukocyte antigen (HLA) complex P5 (HCP5) in OS, aiming to provide a novel molecular mechanism for OS. HCP5 was up-regulated both in OS tissues and cell lines and high expression of HCP5 was associated to low survival in OS patients. Down-regulation of HCP5 inhibited cell proliferation, migration, and invasion, suggesting its carcinogenic role in OS. miR-101 was targeted by HCP5 and its expression was decreased in OS. The inhibitor of miR-101 reversed the impact of HCP5 down-regulation on cell proliferation, apoptosis, and metastasis in OS. Ephrin receptor 7 (EPHA7) was proved to be a target of miR-101 and had ability to recover the effects of miR-101 inhibitor in OS. In conclusion, lncRNA HCP5 knockdown suppressed cell proliferation, migration, and invasion, and induced apoptosis through depleting the expression of EPHA7 by binding to miR-101, providing a potential therapeutic strategy of HCP5 in OS.

Catecholamine levels and gene expression of their receptors in tissues of adults with osteosarcoma.

AIM: The purpose of this work was to identify and measure catecholamines, their metabolites, and the gene expression of catecholamine receptors in osteosarcoma tissue. MATERIALS AND METHODS: The levels of 3,4-dihydroxyphenylacetic acid, norepinephrine, serotonin, and 5-hydroxyindoleacetic acid in cancer tissue and in adjacent and non-oncological bone tissue were analysed by high-performance liquid chromatography, and the gene expression of catecholamine receptors and of dopamine ß-hydroxylase, monoaminoxidase, ki67, and Runx2 in the osteosarcoma tissue, tissue adjacent to the tumour, non-oncological bone, and human brain tissue was analysed by RT-PCR. RESULTS: We found significantly higher levels of 3,4-dihydroxyphenylacetic acid and norepinephrine in the cancer sample than in adjacent and non-oncological bone. We found that ß-adrenergic receptors and dopaminergic receptors, dopamine ß-hydroxylase, ki67, Runx2, and serotonergic receptor gene expression were significantly higher in tumour tissue than in adjacent and non-oncological bone. CONCLUSION: Catecholamines and their receptors could be potential molecular markers for osteosarcoma progression.