Overexpression of miR-92a promotes the tumor growth of osteosarcoma by suppressing F-box and WD repeat-containing protein 7

The Landscape of microRNAs in Bone Tumor: A Comprehensive Review in Recent Studies

Cancer, the second greatest cause of mortality worldwide, frequently causes bone metastases in patients with advanced-stage carcinomas such as prostate, breast, and lung cancer. The existence of these metastases contributes to the occurrence of skeletal-related events (SREs), which are defined by excessive pain, pathological fractures, hypercalcemia, and spinal cord compression. These injurious incidents leave uncomfortably in each of the cancer patient's life quality. Primary bone cancers, including osteosarcoma (OS), chondrosarcoma (CS), and Ewing's sarcoma (ES), have unclear origins. MicroRNA (miRNA) expression patterns have been changed in primary bone cancers such as OS, CS, and ES, indicating a role in tumor development, invasion, metastasis, and treatment response. These miRNAs are persistent in circulation and exhibit distinct patterns in many forms of bone tumors, making them potential biomarkers for early detection and treatment of such diseases. Given their crucial regulatory functions in various biological processes and conditions, including cancer, this study aims to look at miRNAs' activities and possible contributions to bone malignancies, focusing on OS, CS, and ES. In conclusion, miRNAs are valuable tools for diagnosing, monitoring, and predicting OS, CS, and ES outcomes. Further research is required to fully comprehend the intricate involvement of miRNAs in these bone cancers and to develop effective miRNA-based treatments.

Involvement of Small Non-Coding RNA and Cell Antigens in Pathogenesis of Extramedullary Multiple Myeloma

Extramedullary multiple myeloma (EMD) is an aggressive disease; malignant plasma cells lose their dependence in the bone marrow microenvironment and migrate into tissues. EMD is a negative prognostic factor of survival. Using flow cytometry and next-generation sequencing, we aimed to identify antigens and microRNAs (miRNAs) involved in EMD pathogenesis. Flow cytometry analysis revealed significant differences in the level of clonal plasma cells between MM and EMD patients, while the expression of CD markers was comparable between these two groups. Further, miR-26a-5p and miR-30e-5p were found to be significantly down-regulated in EMD compared to MM. Based on the expression of miR-26a-5p, we were able to distinguish these two groups of patients with high sensitivity and specificity. In addition, the involvement of deregulated miRNAs in cell cycle regulation, ubiquitin-mediated proteolysis and signaling pathways associated with infections or neurological disorders was observed using GO and KEGG pathways enrichment analysis. Subsequently, a correlation between the expression of analyzed miRNAs and the levels of CD molecules was observed. Finally, clinicopathological characteristics as well as CD antigens associated with the prognosis of MM and EMD patients were identified. Altogether, we identified several molecules possibly involved in the transformation of MM into EMD.

Advances in the Biological Functions and Mechanisms of miRNAs in the Development of Osteosarcoma

Osteosarcoma is one of the most common primary malignant bone tumors, mainly occurring in children and adolescents, and is characterized by high morbidity and poor prognosis. MicroRNAs, a class of noncoding RNAs consisting of 19 to 25 nucleotides, are involved in cell proliferation, invasion, metastasis, and apoptosis to regulate the development and progression of osteosarcoma. Studies have found that microRNAs are closely related to the diagnosis, treatment, and prognosis of osteosarcoma patients and have an important role in improving drug resistance in osteosarcoma. This paper reviews the role of microRNAs in the pathogenesis of osteosarcoma and their clinical value, aiming to provide a new research direction for diagnosing and treating osteosarcoma and achieving a better prognosis.

MicroRNA-92a Inhibits the Cell Viability and Metastasis of Prostate Cancer by Targeting SOX4

MicroRNAs (miRNAs) was confirmed to play an active role in the pathogenesis of prostate cancer (PCa). The expression and biological function for miR-92a in PCa remains unknown. In this study, we demonstrated that miR-92a expression was decreased in PCa tissues and cells lines. Overexpression miR-92a inhibited the cell viability, migration and invasion of PC-3 while inhibition of miR-92a led to opposite alteration of cell viability and metastasis of DU-145 cells. Mechanically, we confirmed that miR-92a interacted with 3’-UTR of SOX4 through the complementary sequences by luciferase reporter assay. qRT-PCR and western blot confirmed that miR-92a inhibited the expression of SOX4 in PCa cells. Moreover, overexpression of SOX4 reversed the inhibitory effects of miR-92a overexpression on PC-3 cell viability, migration and invasion, while knockdown of SOX4 suppressed the promoting effects of miR-92a knockdown on these biological functions of DU-145 cells. Therefore, our study indicates that miR-92a inhibits the growth and metastasis of prostate cancer by targeting SOX4, and can potentially serve as a biomarker and treatment target for PCa patients.

MicroRNA‑92a promotes non‑small cell lung cancer cell growth by targeting tumor suppressor gene FBXW7

MicroRNA (miRNA/miR)‑92a has been identified as being significantly downregulated in non‑small cell lung cancer (NSCLC) tissues using a miRNA array. However, its biological function and molecular mechanisms in NSCLC have not been fully elucidated. The aim of the present study was to determine the role of miR‑92a in NSCLC and the mechanisms by which it affects NSCLC cells. The expression levels of miR‑92a in NSCLC tissues and cell lines were analyzed using reverse transcription‑quantitative PCR. Cell viability and cell apoptosis were determined using an MTT assay and flow cytometry, respectively. It was observed that miR‑92a was significantly upregulated in NSCLC tissues and cell lines. Inhibition of miR‑92a significantly suppressed viability of NSCLC cells, with concomitant downregulation of key proliferative genes, such as proliferating cell nuclear antigen and Ki‑67. miR‑92a downregulation induced apoptosis of NSCLC cells, as evidenced by flow cytometry and apoptosis‑related protein detection. Luciferase assays confirmed that miR‑92a could directly bind to the 3'‑untranslated region of tumor suppressor F‑box/WD repeat‑containing protein 7 (FBXW7) and suppress its translation. Furthermore, small interfering RNA‑mediated FBXW7 inhibition partially attenuated the tumor suppressive effect of an miR‑92a inhibitor on NSCLC cells. Collectively, these findings demonstrated that miR‑92a might function as an oncogene in NSCLC by regulating FBXW7. In conclusion, miR‑92a could serve as a potential therapeutic target in NSCLC treatment.

miR-487a performs oncogenic functions in osteosarcoma by targeting BTG2 mRNA

Aberrant microRNA (miRNA) expression plays a critical role in osteosarcoma (OS) pathogenesis. In this study, we elucidated the involvement of miR-487a in OS and the underlying molecular mechanisms. We found that miR-487a was upregulated in OS clinical samples and cell lines. Knockdown of miR-487a suppressed OS cell growth and invasion and induced apoptosis; however, overexpression of miR-487a promoted OS cell growth and invasion. Accordingly, downregulation of miR-487a significantly suppressed tumor growth of OS xenografts in vivo. Furthermore, B-cell translocation gene 2 (BTG2) mRNA was found to be a novel target of miR-487a. Knockdown of BTG2 using small interfering RNA (siRNA) recapitulated the oncogenic effects of miR-487a, whereas BTG2 overexpression partially reversed these effects. Finally, miR-487a levels were found to be negatively correlated with BTG2 expression in OS clinical samples. Collectively, our data suggest that miR-487a is an oncogenic miRNA in OS and it lowers BTG2 expression.

MicroRNA-92a as a marker of treatment response and survival in adult acute myeloid leukemia patients

This prospective study assessed circulating miR-92a levels in acute myeloid leukemia (AML) at diagnosis and after induction therapy and followed patients for a maximum of 30 months. The study included 63 consecutive adult AML patients. Circulating miR-92a levels were assessed using real-time polymerase chain reaction (RT-PCR). There was significant rise of miR-92a expression after induction (median (range): 0.297 (0.001-3.438)) in comparison to the reported levels at diagnosis (median (range): 0.236 (0.001-3.305)). Post-induction levels of miR-92a are significantly higher in patients who achieved CR in comparison to patients without CR (median (range): 0.408 (0.017-3.438) vs. 0.01 (0.001-1.010), p<.001). Cox hazard regression analysis identified miR-92a as a significant predictor of OS and DFS in univariate and multivariate analyses. In conclusion, baseline circulating miR-92a in AML patients may be a useful prognostic marker of treatment response and survival over 2.5 years follow up.

Aberrant methylation of WD-repeat protein 41 contributes to tumour progression in triple-negative breast cancer

WD-repeat proteins are implicated in a variety of biological functions, most recently in oncogenesis. However, the underlying function of WD-repeat protein 41 (WDR41) in tumorigenesis remains elusive. The present study was aimed to explore the role of WDR41 in breast cancer. Combined with Western blotting and immunohistochemistry, the results showed that WDR41 was expressed at low levels in breast cancer, especially in triple-negative breast cancer (TNBC). Using methylation-specific PCR (MSP), we observed that WDR41 presented hypermethylation in MDA-MB-231 cells. Methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-dC) management increased the expression of WDR41 in MDA-MB-231 cells, but not in MCF-10A (normal mammary epithelial cells) or oestrogen receptor-positive MCF-7 breast cancer cells. WDR41-down-regulation promoted, while WDR41-up-regulation inhibited the tumour characteristics of TNBC cells including cell viability, cell cycle and migration. Further, WDR41-up-regulation dramatically suppressed tumour growth in vivo. Mechanistically, WDR41 protein ablation activated, while WDR41-up-regulation repressed the AKT/GSK-3β pathway and the subsequent nuclear activation of β-catenin in MDA-MB-231 cells, and 5-aza-dC treatment enhanced this effect. After treatment with the AKT inhibitor MK-2206, WDR41-down-regulation-mediated activation of the GSK-3β/β-catenin signalling was robustly abolished. Collectively, methylated WDR41 in MDA-MB-231 cells promotes tumorigenesis through positively regulating the AKT/GSK-3β/β-catenin pathway, thus providing an important foundation for treating TNBC.

Identification of the AQP8-miR-92a network associated with the aggressive traits of colorectal cancer

Even though earlier reports have revealed that Aquaporin 8 (AQP8) exert essential roles in diverse malignancies, its relationship between specific microRNAs (miRNAs) in regulation of colorectal carcinoma (CRC) progression has never been elaborated. Herein, we proved that AQP8 was downregulated in CRC and high level of AQP8 was significantly associated with better survival in CRC patients. Overexpression of AQP8 restrained CRC cell proliferation, migration and invasion capacities in vitro. In vivo, upregulation of AQP8 also suppressed CRC cell growth. Mechanistic analyses illustrated that AQP8 was a directly target of miR-92a. The expression of AQP8 was negatively modulated by miR-92a. Rescues analysis indicated that miR-92a facilitated CRC cell growth and invasion via modulating the expression of AQP8. Our work validated that miR-92a regulated the aggressiveness of CRC cell via targeting AQP8.

Recent insight into the role of FBXW7 as a tumor suppressor

FBXW7 (also known as Fbw7, Sel10, hCDC4, or hAgo) is a tumor suppressor and the most frequently mutated member of the F-box protein family in human cancers. FBXW7 functions as the substrate recognition component of an SCF-type E3 ubiquitin ligase. It specifically controls the proteasome-mediated degradation of many oncoproteins such as c-MYC, NOTCH, KLF5, cyclin E, c-JUN, and MCL1. In this review, we summarize the molecular and biological features of FBXW7 and its substrates as well as the impact of mutations of FBXW7 on cancer development. We also address the clinical potential of anticancer therapy targeting FBXW7.

Targeting SCF E3 Ligases for Cancer Therapies

SKP1-cullin-1-F-box-protein (SCF) E3 ubiquitin ligase complex is responsible for the degradation of proteins in a strictly regulated manner, through which it exerts pivotal roles in regulating various key cellular processes including cell cycle and division, apoptosis, and differentiation. The substrate specificity of the SCF complex largely depends on the distinct F-box proteins, which function in either tumor promotion or suppression or in a context-dependent manner. Among the 69 F-box proteins identified in human genome, FBW7, SKP2, and β-TRCP have been extensively investigated among various types of cancer in respective of their roles in cancer development, progression, and metastasis. Moreover, several specific inhibitors have been developed to target those E3 ligases, and their efficiency in tumors has been determined. In this review, we provide a summary of the roles of SCF E3 ligases in cancer development, as well as the potential application of miRNA or specific inhibitors for cancer therapy.

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-92a Family: A Novel Diagnostic Biomarker and Potential Therapeutic Target in Human Cancers

Purpose: This study tried to explore whether members of miR-92a family contribute to early diagnosis and prognosis for human cancers and how they work.

Methods: Integrated meta-analysis retrieved from public repositories was employed to assess the clinical roles of the miR-92a family for cancer diagnosis and prognosis. Expression level of miR-92a was detected by the TCGA database and was confirmed by non-small-cell lung cancer (NSCLC) tissues. Targets of miR-92a were predicted using starbase, and validated by dual luciferase assay. Correlation between miR-92a and the target gene was assessed by linkedOmics while expression of the target gene and its role in cancer prognosis were analyzed with UALCAN and Gepia.

Results: We recognized the miR-92a family could serve as a potential diagnostic biomarker with a pooled sensitivity of 0.85 [0.81–0.88] and specificity of 0.86 [0.83–0.90]. The overall hazard ratio (HR) was 2.26 [95% CI: 1.70–3.00] for high expression groups compared to low expression groups. Expression of miR-92a was identified to be upregulated in NSCLC, especially in lung squamous cell carcinoma (LUSC). Results from starbase and dual luciferase assay indicated the regulator of G-protein signaling 3 (RGS3) was a direct target of miR-92a. Statistical negative correlation was found for the expression of miR-92a and RGS3. In addition, expression of RGS3 was downregulated in NSCLC and patients with the high expression had a poor prognosis (HR = 1.3) for LUSC patients. However, results were to the contrary for lung adenocarcinoma (HR = 0.7).

Conclusion: This study revealed that miR-92a family could be ideal biomarkers for cancer diagnosis and prognosis, which might function through targeting RGS3.

MiR-223 promotes oral squamous cell carcinoma proliferation and migration by regulating FBXW7

Abnormally expressed microRNAs (miRNAs) contribute widely to human cancer, including oral squamous cell carcinoma (OSCC), by regulating their downstream targets. MiR-223 has been proved to be up-regulated in both gastric cancer and ovarian cancer. However, the effect of miR-223 on OSCC is still unclear. Here, we showed that miR-223 was over-expressed in OSCC tissues using qRT-PCR. Next, we investigated the biological mechanism of miR-223 in OSCC. The results demonstrated that miR-223 facilitated the cell proliferation and migration of OSCC using MTT assay and Transwell assay. Furthermore, we stated that the FBXW7 expression was decreased in OSCC and re-expression of FBXW7 inhibited the proliferation and migration of OSCC. In addition, FBXW7 mimic inversed the promotion effect of miR-223 in regulating of OSCC cells. In short, miR-223 promoted OSCC cell proliferation and migration by downregulating FBXW7, which provided a novel therapeutic strategy for OSCC.

Investigation of MiR-92a as a Prognostic Indicator in Cancer Patients: a Meta-Analysis

Background: MiR-92a has been discovered to be involved in the malignant behavior of various types of cancers. However, the particular clinical and prognostic roles of miR-92a in tumors still need to be identified more precisely. The current meta-analysis assessed the prognostic value of miR-92a in various carcinomas.

Methods: Systematic literature searches of PubMed, PMC, Web of Science (WOS), Embase in English and Wanfang, SinoMed and the China National Knowledge Infrastructure (CNKI) in Chinese up to Jan 15^th 2019 were conducted for eligible studies. Twenty studies involving a total of 2573 patients were included in the analysis. Pooled hazard ratios (HR) for overall survival (OS) and disease-free survival (DFS), progression-free survival (PFS) and recurrence-free survival (RFS) were assessed using fixed-effects and random-effects models. Meta-regression and subgroup analyses were carried out to explore the source of heterogeneity. Odds ratio (OR) and 95%CIs were applied to evaluate the relationship between miR-92a expression levels and clinicopathological characteristics.

Results: A significant association between miR-92a levels and OS (HR=2.18) was identified. The random pooling model also revealed significance of consistency (HR=2.14), indicating that the stability of the results. Subgroup analyses were performed and the corresponding significance was recognized in Chinese cancer patients (HR=2.35), studies of specimen derived from tissues (HR=2.43), non-hematological cancer (HR=2.35), osteosarcoma (HR=2.54), non-small cell lung cancer (HR=2.33), hepatocellular carcinoma (HR=2.40) and so on. There were significant relations observed of the expression level of miR-92a to tumor size (≥5 vs <5 cm) (OR=2.13), lymph node metastasis (present vs. absent) (OR=1.87), distant metastasis (present vs. absent) (OR=2.99) and so on.

Conclusions: the over expression of miR-92a is associated with unfavorable prognosis of Chinese cancer patients. In addition, patients of elevated miR-92a expression level are likely to develop the cancers of more malignant behaviors.

Role of microRNA-92a in metastasis of osteosarcoma cells in vivo and in vitro by inhibiting expression of TCF21 with the transmission of bone marrow derived mesenchymal stem cells

Background

This study aims to investigate the role of microRNA-92a (miR-92a) in metastasis of osteosarcoma (OS) cells in vivo and in vitro by regulatingTCF21 with the transmission of bone marrow derived mesenchymal stem cells (BMSCs).

Methods

BMSCs were isolated, purified and cultured from healthy adult bone marrow tissues. The successfully identified BMSCs were co-cultured with OS cells, and the effects of BMSCs on the growth metastasis of OS cells in vitro and in vivo were determined. qRT-PCR and western blot analysis was used to detect the expression of miR-92a and TCF21 in OS cells and OS cells co-cultured with BMSCs. Proliferation, invasion and migration of OS cells transfected with miR-92a mimics and miR-92a inhibitors was determined, and the tumorigenesis and metastasis of OS cells in nude mice were observed. Expression of miR-92a and TCF21 mRNA in tissue specimens as well as the relationship between the expression of miR-92a and the clinicopathological features of OS was analyzed.

Results

BMSCs promoted proliferation, invasion and migration of OS cells in vitro together with promoted the growth and metastasis of OS cells in vivo. Besides, high expression of miR-92a was found in OS cells co-cultured with BMSCs. Meanwhile, overexpression of miR-92a promoted proliferation, invasion and migration of OS cells in vitro as well as promoted growth and metastasis of OS cells in vivo. The expression of miR-92a increased significantly, and the expression of TCF21 mRNA and protein decreased significantly in OS tissues. Expression of miR-92a was related to Ennecking staging and distant metastasis in OS patients.

Conclusion

Collectively, this study demonstrates that the expression of miR-92a is high in OS and BMSCs transfers miR-92a to inhibit TCF21 and promotes growth and metastasis of OS in vitro and in vivo.

Baicalin, the major component of traditional Chinese medicine Scutellaria baicalensis induces colon cancer cell apoptosis through inhibition of oncomiRNAs

Colorectal cancer (CRC) is among the most frequently occurring cancers worldwide. Baicalin is isolated from the roots of Scutellaria baicalensis and is its dominant flavonoid. Anticancer activity of baicalin has been evaluated in different types of cancers, especially in CRC. However, the molecular mechanisms underlying the contribution of baicalin to the treatment of CRC are still unknown. Here, we confirmed that baicalin can effectively induce and enhance apoptosis in HT-29 cells in a dose-dependent manner and suppress tumour growth in xenografted nude mice. We further performed a miRNA microarray analysis of baicalin-treated and untreated HT-29 cells. The results showed that a large number of oncomiRs, including miR-10a, miR-23a, miR-30c, miR-31, miR-151a and miR-205, were significantly suppressed in baicalin-treated HT-29 cells. Furthermore, our in vitro and in vivo studies showed that baicalin suppressed oncomiRs by reducing the expression of c-Myc. Taken together, our study shows a novel mechanism for anti-cancer action of baicalin, that it induces apoptosis in colon cancer cells and suppresses tumour growth by reducing the expression of c-Myc and oncomiRs.

Crosstalk between Hedgehog pathway and energy pathways in human adipose-derived stem cells: A deep sequencing analysis of polysome-associated RNA

Adult stem cells are considered promising candidates for cellular therapies due to their capacity to differentiate and self-renew. Differentiation leads to changes in the metabolism, structure, and gene expression patterns of cells. Hedgehog is one of the pathways that is involved in the enhancement of osteogenesis and chondrogenesis in adult stem cells, but its mechanisms are poorly understood. In this study, we treated adipose tissue-derived stem cells (ADSC) with two well-characterized drugs, purmorphamine (Hedgehog pathway activator) and cyclopamine (Hedgehog pathway inhibitor), and identified mRNAs associated with polysomes in each treatment group to determine the post transcriptional genetic networks governed by the Hedgehog pathway. Activation of the Hedgehog pathway by purmorphamine results in significant upregulation of mRNAs associated with cellular communication and signal transduction. Furthermore, our experiments show that cyclopamine acts late downregulating GLI1 expression in ADSCs but promotes the upregulation of mRNAs associated with energy pathways and metabolism at early times. Through in silico analysis, we identified some miRNAs, such as miR-355, that could regulate these mRNAs association with polysomes and thereby modulate the Hedgehog pathway. Our results suggest that activation of the Hedgehog pathway by purmorphamine also results in a negative regulation of mRNAs in the protein translation machinery.

The long non-coding RNA SNHG14 inhibits cell proliferation and invasion and promotes apoptosis by sponging miR-92a-3p in glioma

Malignant glioma is one of the most common types of primary brain tumours. Long non-coding RNAs (lncRNAs) have recently emerged as a new class of therapeutic targets for many cancers. In this study, we aimed to explore the functional involvement of small nucleolar RNA host gene 14 (SNHG14) and its potential regulatory mechanism in glioma progression. SNHG14 was found to be downregulated in human glioma tissues and cell lines. SNHG14 significantly inhibited cell viability, reduced cell invasion, and induced apoptosis in glioma cell lines. Furthermore, a correlation analysis demonstrated that there was a negative correlation between SNHG14 expression and miR-92a-3p expression. Bioinformatics prediction and luciferase reporter assays demonstrated that miR-92a-3p could directly bind to SNHG14. miR-92a-3p was significantly upregulated in glioma and acted as an oncogene in glioma cells by inhibiting Bim. Moreover, mechanistic investigations showed that miR-92a-3p could reverse the tumour suppressive effects induced by SNHG14 in glioma, indicating that SNHG14 may act as an endogenous sponge that competes for binding to miR-92a-3p. Our results suggest that SNHG14 and miR-92a-3p may be promising molecular targets for glioma therapy.

miR‑494 inhibits cell proliferation and metastasis via targeting of CDK6 in osteosarcoma

Tumorigenesis is a multistep process involving various cell growth-associated factors. Accumulated evidence indicates that the disordered regulation of microRNAs (miRNAs) contributes to tumorigenesis. However, the detailed mechanism underlying the involvement of miRNAs in oncogenesis remains to be fully elucidated. In the present study, the repressed expression of microRNA (miR)-494 was identified in 18 patients with osteosarcoma (OS) and OS cell lines, compared with corresponding controls. To determine whether deregulated miR-494 exerts tumor-suppressive effects in the development of OS, the effects of miR-494 on cell proliferation and metastasis were evaluated. It was found that the restoration of miR-494 in MG-63 and U2OS cells led to inhibited cell proliferation and attenuated migratory propensity in vitro, determined through analysis using MTT, colony formation and Transwell assays. In addition, overexpression of miR-494 markedly suppressed the tumor volume and weight in vivo. In accordance, the ectopic expression of miR-494 induced cell cycle arrest at the G1/S phase in OS cells. Bioinformatics analysis and luciferase reporter assays were performed to investigate the potential regulatory role of miR-494, the results of which indicated that miR-494 directly targeted cyclin-dependent kinase 6 (CDK6). Of note, the data obtained through reverse transcription-quantitative polymerase chain reaction and western blot analyses suggested that the elevated expression of miR-494 resulted in reduced mRNA and protein expression levels of CDK6. Taken together, these findings indicated that the miR-494/CDK6 axis has a significant tumor-suppressive effect on OS, and maybe a diagnostic and therapeutic target for the treatment of OS.

SPOCK1 promotes the growth of Osteosarcoma cells through mTOR-S6K signaling pathway

SPOCK1 belongs to the SPARC family, which plays an important role in proliferation, invasion and migration of various tumour cells. However, the functions of SPOCK1 in osteosarcoma cell growth and proliferation have not been fully elucidated. In the present study, we found that SPOCK1 is significantly upregulated in osteosarcoma tissue. Moreover, overexpression of SPOCK1 was associated with tumour size, metastasis, Enneking stage and pathological degree. Furthermore, knockdown of SPOCK1 expression suppressed the growth of osteosarcoma cells in vitro and reduced tumourigenicity in nude mice in vivo. Additionally, our data suggest that inactivation of the mTOR-S6K signaling pathway participated in inhibition of SPOCK1-mediated suppression of osteosarcoma cell growth. These findings represent a novel pathogenetic mechanism of osteosarcoma development that provides a potential target for therapeutic strategies for osteosarcoma.

Exosomes derived from human umbilical cord mesenchymal stem cells protect against cisplatin-induced ovarian granulosa cell stress and apoptosis in vitro

Human umbilical cord mesenchymal stem cells (huMSCs) can treat primary ovarian insufficiency (POI) related to ovarian granulosa cell (OGC) apoptosis caused by cisplatin chemotherapy. Exosomes are a class of membranous vesicles with diameters of 30–200 nm that are constitutively released by eukaryotic cells. Exosomes mediate local cell-to-cell communication by transferring microRNAs and proteins. In the present study, we demonstrated the effects of exosomes derived from huMSCs (huMSC-EXOs) on a cisplatin-induced OGC model in vitro and discussed the preliminary mechanisms involved in these effects. We successfully extracted huMSC-EXOs from huMSC culture supernatant and observed the effective uptake of exosomes by cells with fluorescent staining. Using flow cytometry (with annexin-V/PI labelling), we found that huMSC-EXOs increased the number of living cells. Western blotting showed that the expression of Bcl-2 and caspase-3 were upregulated, whilst the expression of Bax, cleaved caspase-3 and cleaved PARP were downregulated to protect OGCs. These results suggest that huMSC-EXOs can be used to prevent and treat chemotherapy-induced OGC apoptosis in vitro. Therefore, this work provides insight and further evidence of stem cell function and indicates that huMSC-EXOs protect OGCs from cisplatin-induced injury in vitro.