Downregulation of tumor suppressing STF cDNA 3 promotes epithelial-mesenchymal transition and tumor metastasis of osteosarcoma by the Wnt/GSK-3β/β-catenin/Snail signaling pathway

RANK/RANKL axis promotes migration, invasion, and metastasis of osteosarcoma via activating NF-κB pathway

Osteosarcoma (OS) is one of the most prevalent primary bone tumors with a high degree of metastasis and poor prognosis. Epithelial-to-mesenchymal transition (EMT) is a cellular mechanism that contributes to the invasion and metastasis of cancer cells, and OS cells have been reported to exhibit EMT-like characteristics. Our previous studies have shown that the interaction between tumor necrosis factor superfamily member 11 (TNFRSF11A; also known as RANK) and its ligand TNFSF11 (also known as RANKL) promotes the EMT process in breast cancer cells. However, whether the interaction between RANK and RANKL enhances aggressive behavior by inducing EMT in OS cells has not yet been elucidated. In this study, we showed that the interaction between RANK and RANKL increased the migration, invasion, and metastasis of OS cells by promoting EMT. Importantly, we clarified that the RANK/RANKL axis induces EMT by activating the nuclear factor-kappa B (NF-κB) pathway. Furthermore, the NF-κB inhibitor dimethyl fumarate (DMF) suppressed migration, invasion, and EMT in OS cells. Our results suggest that the RANK/RANKL axis may serve as a potential tumor marker and promising therapeutic target for OS metastasis. Furthermore, DMF may have clinical applications in the treatment of lung metastasis in patients with OS.

LINC01060 knockdown inhibits osteosarcoma cell malignant behaviors in vitro and tumor growth and metastasis in vivo through the PI3K/Akt signaling

Despite its low frequency, osteosarcoma is one of the deadliest malignancies in children and adolescents. The phosphatidylinositol 3-kinase (PI3K)/Akt signaling activation and epithelial-to-mesenchymal transition (EMT) are critical issues during osteosarcoma development. This study found long intergenic non-protein coding RNA 1060 (LINC01060) to be an EMT-related long non-coding RNA (lncRNA) up-regulated in osteosarcoma; higher LINC01060 expression was linked to a worse prognosis in osteosarcoma patients. In vitro, knocking down LINC01060 significantly inhibits osteosarcoma cell malignant behaviors, including hyperproliferation, invasion, migration, and EMT. In vivo, LINC01060 knockdown inhibited tumor growth and metastasis, and suppressed PI3K and Akt phosphorylation. In osteosarcoma cells, Akt agonist SC79 exerted opposite effects to those of LINC01060 knockdown through the promotion of cell viability, cell migration, and cell invasion. Moreover, the Akt agonist SC79 partially eliminated LINC01060 knockdown effects on osteosarcoma cells, suggesting that LINC01060 exerts its effects through the PI3K/Akt signaling. Therefore, it is deduced that LINC01060 is overexpressed in osteosarcoma. In vitro, LINC01060 knockdown inhibits cancer cell malignant behaviors; in vivo, LINC01060 knockdown inhibits tumor development and metastasis. The PI3K/Akt signaling is involved in LINC01060 functions in osteosarcoma.

Regulatory role of miRNAs on Wnt/β-catenin signaling in tumorigenesis of glioblastoma

Glioblastoma (GBM) is one of the most aggressive tumors in the brain with high mortality worldwide. Despite recent advances in therapeutic strategies, the survival rate remains low in patients with GBM. The pathogenesis of GBM is a very complicated process involving various genetic mutations affecting several oncogenic signaling pathways like Wnt/β-catenin axis. Overactivation of the Wnt/β-catenin signaling pathway is associated with decreased survival and poor prognosis in patients with GBM. MicroRNAs (miRNAs) were shown to play important roles in the regulation of cell proliferation, differentiation, apoptosis, and tumorigenesis by modulating the expression of their target genes. Aberrant expression of miRNAs were reported in various human malignancies including GBM, breast, colorectal, liver, and prostate cancers, but little is known about their cellular mechanisms. Therefore, recognition of the expression profile and regulatory effects of miRNAs on the Wnt/β-catenin pathway may offer a novel approach for the classification, diagnosis, prognosis, and treatment of patients with GBM. This review summarizes previous data on the modulatory role of miRNAs on the Wnt/β-catenin pathway implicated in tumorigenesis of GBM.

Tris(1,3-dichloro-2-propyl) Phosphate Inhibits Early Embryonic Development by Binding to Gsk-3β Protein in Zebrafish

Recently, several studies have reported that exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) results in abnormal development of zebrafish embryos in blastocyst and gastrula stages, but molecular mechanisms are still not clear. This lacking strongly affects the interspecific extrapolation of embryonic toxicity induced by TDCIPP and hazard evaluation. In this study, zebrafish embryos were exposed to 100, 500 or 1000 μg/L TDCIPP, and 6-bromoindirubin-3'-oxime (BIO, 35.62 μg/L) was used as a positive control. Results demonstrated that treatment with TDCIPP or BIO caused an abnormal stacking of blastomere cells in mid blastula transition (MBT) stage, and subsequently resulted in epiboly delay of zebrafish embryos. TDCIPP and BIO up-regulated the expression of β-catenin protein and increased its accumulation in nuclei of embryonic cells. This accumulation was considered as a driver for early embryonic developmental toxicity of TDCIPP. Furthermore, TDCIPP and BIO partly shared the same modes of action, and both of them could bind to Gsk-3β protein, and then decreased the phosphorylation level of Gsk-3β in TYR·216 site and lastly inhibited the activity of Gsk-3β kinase, which was responsible for the increased concentrations of β-catenin protein in embryonic cells and accumulation in nuclei. Our findings provide new mechanisms for clarifying the early embryonic developmental toxicity of TDCIPP in zebrafish.

FOSL1 transcriptionally regulates PHLDA2 to promote 5-FU resistance in colon cancer cells

BACKGROUND

Tumor drug resistance is a leading cause of tumor treatment failure. To date, the association between FOS-Like antigen-1 (FOSL1) and chemotherapy sensitivity in colon cancer is unclear. The present study investigated the molecular mechanism of FOSL1 regulating 5-Fluorouracil (5-FU) resistance in colon cancer.

METHODS

FOSL1 expression in colon cancer was analyzed by bioinformatics methods, and its downstream regulatory factors were predicted. Pearson correlation analyzed the expression of FOSL1 and downstream regulatory gene. Meanwhile, the expression of FOSL1 and its downstream factor Pleckstrin Homology-Like Domain Family A Member 2 (PHLDA2) in colon cancer cell lines was measured by qRT-PCR and western blot. The regulatory relationship between FOSL1 and PHLDA2 was verified by chromatin immunoprecipitation (ChIP) assay and dual-luciferase reporter assay. The effects of the FOSL1/PHLDA2 axis on the resistance in colon cancer cells to 5-FU were analyzed by cell experiments.

RESULTS

FOSL1 expression was evidently up-regulated in colon cancer and 5-FU resistant cells. FOSL1 was positively correlated with PHLDA2 in colon cancer. In vitro cell assays showed that low expression of FOSL1 significantly enhanced 5-FU sensitivity in colon cancer cells, significantly suppressed the proliferation of cancer cells, and induced apoptosis. Overexpression of FOSL1 presented the opposite regulatory trend. Mechanistically, FOSL1 activated PHLDA2 and up-regulated its expression. Moreover, by activating glycolysis, PHLDA2 promoted 5-Fu resistance and cell proliferation, and reduced cell apoptosis in colon cancer.

CONCLUSION

Down-regulated FOSL1 expression could enhance the 5-FU sensitivity of colon cancer cells, and FOSL1/PHLDA2 axis may be an effective target for overcoming chemotherapy resistance in colon cancer.

Regulation of the Epithelial to Mesenchymal Transition in Osteosarcoma

The epithelial to mesenchymal transition (EMT) is a cellular process that has been linked to the promotion of aggressive cellular features in many cancer types. It is characterized by the loss of the epithelial cell phenotype and a shift to a more mesenchymal phenotype and is accompanied by an associated change in cell markers. EMT is highly complex and regulated via multiple signaling pathways. While the importance of EMT is classically described for carcinomas-cancers of epithelial origin-it has also been clearly demonstrated in non-epithelial cancers, including osteosarcoma (OS), a primary bone cancer predominantly affecting children and young adults. Recent studies examining EMT in OS have highlighted regulatory roles for multiple proteins, non-coding nucleic acids, and components of the tumor micro-environment. This review serves to summarize these experimental findings, identify key families of regulatory molecules, and identify potential therapeutic targets specific to the EMT process in OS.

Artemin Promotes the Migration and Invasion of Cervical Cancer Cells through AKT/mTORC1 Signaling

BACKGROUND

The neurotrophic factor Artemin (ARTN) is involved in tumor proliferation and metastasis. Nonetheless, ARTN's significance in cervical cancer (CC) has not been studied. In our study, we propose to investigate the biological function of ARTN in CC as well as its particular regulatory mechanism.

METHODS

Immunohistochemistry (IHC) was used to examine the degree of ARTN protein expression in CC patient tissue. Real-time PCR and Western blotting were performed to reveal related genes' levels in CC cells. The CCK-8 test, the colony formation assay, the wound-healing assay, and the transwell assay were utilized to determine the proliferation, migration, and invasion capabilities, respectively. To generate lung metastasis models, stable ARTN-expressing SiHa cells were injected into the caudal tail vein of mice. IHC was used to examine the protein levels in CC mice model tissues.

RESULTS

ARTN was overexpressed in CC tissues relative to normal cervical tissues and linked positively with lymph node metastases (P=0.012) and recurrence (P=0.015) in CC patients. In vitro, ARTN overexpression promoted the proliferation, invasion, and migration of CC cells. In contrast, the consequences of depleting endogenous ARTN were the opposite. Moreover, overexpression of ARTN increased lung metastasis of CC cells in vivo and shortened the lifespan of mice models. In addition, ARTN overexpression significantly enhanced AKT phosphorylation on Ser473 and mTOR phosphorylation on Ser2448 and promoted the epithelial-mesenchymal transition (EMT) cascade. In addition, rapamycin, a selective inhibitor of mTORC1, might rescue the EMT phenotype caused by ARTN.

CONCLUSION

Our findings suggested that ARTN may enhance CC metastasis through the AKT/mTORC1 pathway. ARTN is anticipated to be a novel potential therapeutic target for the treatment of CC metastases.

Reversion of methionine addiction of osteosarcoma cells to methionine independence results in loss of malignancy, modulation of the epithelial-mesenchymal phenotype and alteration of histone-H3 lysine-methylation

Methionine addiction, a fundamental and general hallmark of cancer, known as the Hoffman Effect, is due to altered use of methionine for increased and aberrant transmethylation reactions. However, the linkage of methionine addiction and malignancy of cancer cells is incompletely understood. An isogenic pair of methionine-addicted parental osteosarcoma cells and their rare methionine-independent revertant cells enabled us to compare them for malignancy, their epithelial-mesenchymal phenotype, and pattern of histone-H3 lysine-methylation. Methionine-independent revertant 143B osteosarcoma cells (143B-R) were selected from methionine-addicted parental cells (143B-P) by their chronic growth in low-methionine culture medium for 4 passages, which was depleted of methionine by recombinant methioninase (rMETase). Cell-migration capacity was compared with a wound-healing assay and invasion capability was compared with a transwell assay in 143B-P and 143B-R cells in vitro. Tumor growth and metastatic potential were compared after orthotopic cell-injection into the tibia bone of nude mice in vivo. Epithelial-mesenchymal phenotypic expression and the status of H3 lysine-methylation were determined with western immunoblotting. 143B-P cells had an IC50 of 0.20 U/ml and 143B-R cells had an IC50 of 0.68 U/ml for treatment with rMETase, demonstrating that 143B-R cells had regained the ability to grow in low methionine conditions. 143B-R cells had reduced cell migration and invasion capability in vitro, formed much smaller tumors than 143B-P cells and lost metastatic potential in vivo, indicating loss of malignancy in 143B-R cells. 143B-R cells showed gain of the epithelial marker, ZO-1 and loss of mesenchymal markers, vimentin, Snail, and Slug and, an increase of histone H3K9me3 and H3K27me3 methylation and a decrease of H3K4me3, H3K36me3, and H3K79me3 methylation, along with their loss of malignancy. These results suggest that shifting the balance in histone methylases might be a way to decrease the malignant potential of cells. The present results demonstrate the rationale to target methionine addiction for improved sarcoma therapy.

The miR-3648/FRAT1-FRAT2/c-Myc negative feedback loop modulates the metastasis and invasion of gastric cancer cells

Although the abnormal expression of miRNAs in cancer cells is a widely accepted phenomenon, the molecular mechanisms underlying miR-3648 progression and metastasis in gastric cancer (GC) remain unclear. miR-3648 expression is downregulated and its ectopic expression in GC cells significantly suppressed cell proliferation and metastasis. Mechanistic analyses indicated that miR-3648 directly targets FRAT1 or FRAT2 and inhibits FRAT1- or FRAT2-mediated invasion and motility in vitro and in vivo. Moreover, FRAT1 physically interacted with FRAT2. Furthermore, FRAT1 overexpression promoted GC cell invasion, whereas siRNA-mediated repression of FRAT2 in FRAT1-overexpressing GC cells reversed its invasive potential. Besides, miR-3648 inactivated the Wnt/β-catenin signalling pathway by downregulating FRAT1 and FRAT2 in GC. Interestingly, c-Myc, a downstream effector of Wnt/β-catenin signalling, was also downregulated by miR-3648 overexpression. In turn, c-Myc negatively regulated miR-3648 expression by binding to the miR-3648 promoter. In addition, miR-3648 expression levels were negatively correlated with c-Myc, FRAT1, and FRAT2 expression in fresh gastric samples. Our studies suggest that miR-3648 acts as a tumour-suppressive miRNA and that the miR-3648/FRAT1-FRAT2/c-Myc negative feedback loop could be a critical regulator of GC progression.

Reticulon 2 promotes gastric cancer metastasis via activating endoplasmic reticulum Ca2+ efflux-mediated ERK signalling

Gastric cancer ranks fourth for mortality globally among various malignant tumours, and invasion and metastasis are the major reason leading to its poor prognosis. Recently, accumulating studies revealed the role of reticulon proteins in cell growth and transmigration. However, the expression and biological function of reticulon proteins in human gastric cancer remain largely unclear. Herein, we explored the potential role of reticulon 2 (RTN2) in the progression of gastric cancer. Tissue microarray was used to determine the expression levels of RTN2 in 267 gastric cancer patients by immunohistochemistry. Gastric cancer cell lines were utilised to examine the influences of RTN2 on cellular migration and invasion abilities, epithelial-to-mesenchymal transition (EMT) and signalling pathway. In vivo studies were also performed to detect the effect of RTN2 on tumour metastasis. We found that RTN2 expression was notably upregulated in tumour tissues compared to pericarcinomatous tissues. High RTN2 expression was positively correlated with patients’ age, vessel invasion, tumour invasion depth, lymph node metastasis and TNM stage. Besides, high RTN2 staining intensity was associated with adverse survival which was further identified as an independent prognostic factor for gastric cancer patients by multivariate analysis. And the predictive accuracy was also improved when incorporated RTN2 into the TNM-staging system. RTN2 could promote the proliferation, migration and invasion of gastric cancer cells in vitro and lung metastasis in vivo. Mechanistically, RTN2 interacted with IP3R, and activated ERK signalling pathway via facilitating Ca²⁺ release from the endoplasmic reticulum, and subsequently drove EMT in gastric cancer cells. These results proposed RTN2 as a novel promotor and potential molecular target for gastric cancer therapies.

Hsa_circ_0087302, a circular RNA, affects the progression of osteosarcoma via the Wnt/β-catenin signaling pathway

Osteosarcoma is the most common malignant tumor in adolescent bone malignancies. It has the characteristics of a high metastasis rate, high mortality and poor prognosis. As a subclass of endogenous noncoding RNAs, circRNAs have been identified to be related to the occurrence, development and prognosis of different kinds of cancers, but the mechanism of their effect on osteosarcoma is not clear. In the present study, we identified a novel circRNA, hsa_circ_0087302, by RNA-seq, and we found that it was expressed at low levels in osteosarcoma. Using RT-PCR, we confirmed that the expression of hsa_circ_0087302 in osteosarcoma cells was lower than that in osteoblasts. Functional validation experiments revealed that hsa_circ_0087302 overexpression inhibited proliferation, cell cycle, migration, and invasion in osteosarcoma cells. Furthermore, Western blotting experiments demonstrated that hsa_circ_0087302 affected the expression of cell cycle- and Wnt/β-catenin signaling pathway-related proteins. For the first time, we identified that hsa_circ_0087302 may affect the malignant biological behavior of osteosarcoma cells through the Wnt/β-catenin signaling pathway. In summary, hsa_circ_0087302 may provide a new direction for the diagnosis and treatment of osteosarcoma.

Osteosarcoma and Metastasis

Osteosarcoma is the most common primary bone malignancy in adolescents. Its high propensity to metastasize is the leading cause for treatment failure and poor prognosis. Although the research of osteosarcoma has greatly expanded in the past decades, the knowledge and new therapy strategies targeting metastatic progression remain sparse. The prognosis of patients with metastasis is still unsatisfactory. There is resonating urgency for a thorough and deeper understanding of molecular mechanisms underlying osteosarcoma to develop innovative therapies targeting metastasis. Toward the goal of elaborating the characteristics and biological behavior of metastatic osteosarcoma, it is essential to combine the diverse investigations that are performed at molecular, cellular, and animal levels from basic research to clinical translation spanning chemical, physical sciences, and biology. This review focuses on the metastatic process, regulatory networks involving key molecules and signaling pathways, the role of microenvironment, osteoclast, angiogenesis, metabolism, immunity, and noncoding RNAs in osteosarcoma metastasis. The aim of this review is to provide an overview of current research advances, with the hope to discovery druggable targets and promising therapy strategies for osteosarcoma metastasis and thus to overcome this clinical impasse.

Downregulation of the Proton-Activated Cl- Channel TMEM206 Inhibits Malignant Properties of Human Osteosarcoma Cells

Transmembrane protein 206 (TMEM206), a proton-activated chloride channel, has been implicated in various biochemical processes, including bone metabolism, and has emerged as a novel cancer-related protein in multiple tumor types. However, its role in primary malignant bone tumors, particularly in osteosarcoma (OS), remains unclear. This study is aimed at exploring the effects of TMEM206 gene silencing on the proliferation, migration, invasion, and metastasis of human OS cells in vitro and in vivo using an shRNA-knockdown strategy. We found that TMEM206 is frequently overexpressed and that high levels of TMEM206 correlated with clinical stage and pulmonary metastasis in patients with OS. We provided evidence that TMEM206-silenced OS cancer cells exhibit decreased proliferation, migration, and invasion in vitro. Mechanistically, we identified β-catenin, a key member of Wnt/β-catenin signaling, as a downstream effector of TMEM206. TMEM206 silencing inhibits the Wnt/β-catenin signaling pathway in expression rescue experiments, confirming that TMEM206 silencing attenuates OS cell tumorigenic behavior, at least in part, via the β-catenin mediated downregulation of Wnt/β-catenin signaling. More importantly, TMEM206 knockdown-related phenotype changes were replicated in a xenograft nude mouse model where pulmonary metastases of OS cells were suppressed. Together, our results demonstrate that silencing TMEM206 negatively modulates the Wnt/β-catenin signaling pathway via β-catenin to suppress proliferation, migration, invasion, and metastasis in OS carcinogenesis, suggesting TMEM206 as a potential oncogenic biomarker and a potential target for OS treatment.

LINC01291 promotes hepatocellular carcinoma development by targeting miR-186-5p/OXSR1 axis

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Recent studies have demonstrated that lncRNAs play an important role in tumorigenesis. LINC01291 has been proven to be involved in the proliferation and migration of different cancers, but the function of LINC01291 in HCC is still unknown.

METHODS

First, the expression of LINC01291 in 50 paired HCC tissues, adjacent normal tissues and HCC cell lines was measured by qRT-PCR. Then, the function of LINC01291 in HCC cell proliferation, migration and invasion was measured by colony formation, Cell Counting Kit-8 (CCK8) assays, wound healing assays and Transwell assays. In addition, E-cadherin, N-cadherin, vimentin and OXSR1 protein expression levels were assessed via western blotting. Luciferase reporter assays were used to prove the relationship between LINC01291 and miR-186-5p as well as miR-186-5p and OXSR1 mRNA. Rescue assays and in vivo experiments further confirmed the LINC01291/miR-186-5p/OXSR1 axis in the progression of HCC.

RESULTS

LINC01291 was upregulated in both HCC tissues and cell lines. Knockdown of LINC01291 inhibited the proliferation, migration, invasion and EMT progression of HCC cells. In addition, LINC01291 could overexpress OXSR1 by sponging miR-186-5p, and OXSR1 overexpression or miR-186-5p inhibition could rescue the effect of LINC01291 knockdown in YY-8103 cell lines. In addition, lentiviral sh-LINC01291 could effectively inhibit the growth of subcutaneous YY-8103 xenograft tumors, while the anticancer effect could be reversed by cotransfection with in-miR-186-5p or ov-OXSR1.

CONCLUSIONS

LINC01291 can promote the proliferation, migration, invasion and EMT of HCC cells via the miR-186-5p/OXSR1 axis, and sh-LINC01291 can inhibit tumor growth in a xenograft mouse model.

Tumor-Suppressing STF cDNA 3 Overexpression Suppresses Renal Fibrosis by Alleviating Anoikis Resistance and Inhibiting the PI3K/Akt Pathway

BACKGROUND

Myofibroblast (MF) activation is the key event of irreversible renal interstitial fibrosis. Anoikis resistance is the hallmark of active MFs, which is conferred by continuous activation of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (Akt) pathway. Our previous study found that tumor-suppressing STF cDNA 3 (TSSC3) enhances the sensitivity of cells to anoikis via the PI3K/Akt pathway. Therefore, we hypothesized that TSSC3 might suppress renal interstitial fibrosis by inducing anoikis via the PI3K/Akt pathway.

METHODS

Cell anoikis was induced by the exogenous addition of RGD-containing peptides or by culturing cells in suspension. MFs were established by stimulating HK-2 renal tubular epithelial cells with transforming growth factor beta 1 (TGF-β1). Lentivirus vectors were to construct a TSSC3 overexpression cell model. The effects of TSSC3 on the anoikis, growth, migration, invasion, and contraction of MFs were determined using annexin V-fluorescein isothiocyanate assays, cell counting kit-8 assays, wound healing migration assays, matrigel invasion assays, and collagen-based contraction assays.

RESULTS

The results demonstrated that TGF-β1, simultaneous with the induction of MF differentiation, confers significant protection against anoikis-induced cell death, which could be partly reversed by treatment with the PI3K/Akt pathway inhibitor, LY294002. Moreover, overexpression of TSSC3 obviously impaired cell growth, cell migration, cell invasion, contraction, and anoikis resistance of MFs, and decreased the activity of the PI3K/Akt pathway and the production of extracellular matrix molecules, all of which could be attenuated by treatment with the PI3K/Akt pathway activator, 740Y-P. Taken together, this study suggested that TSSC3 attenuates the anoikis resistance and profibrogenic ability of TGF-β1-induced MF by regulating the PI3K-Akt pathway.

CONCLUSION

These findings provide a biological basis for further exploration of the therapeutic significance of targeting MF via TSSC3 in renal interstitial fibrosis.

NOP14 regulates the growth, migration, and invasion of colorectal cancer cells by modulating the NRIP1/GSK-3β/β-catenin signaling pathway

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide. Recently, nucleolar complex protein 14 (NOP14) has been discovered to play a critical role in cancer development and progression, but the mechanisms of action of NOP14 in colorectal cancer remain to be elucidated. In this study, we used collected colorectal cancer tissues and cultured colorectal cancer cell lines (SW480, HT29, HCT116, DLD1, Lovo), and measured the mRNA and protein expression levels of NOP14 in colorectal cancer cells using qPCR and Western blotting. GFP-NOP14 was constructed and siRNA fragments against NOP14 were synthesized to investigate the importance of NOP14 for the development of colorectal cells. Transwell migration assays were used to measure cell invasion and migration, CCK-8 kits were used to measure cell activity, and flow cytometry was applied to the observation of apoptosis. We found that both the mRNA and protein levels of NOP14 were significantly upregulated in CRC tissues and cell lines. Overexpression of GFP-NOP14 markedly promoted the growth, migration, and invasion of the CRC cells HT19 and SW480, while genetic knockdown of NOP14 inhibited these behaviors. Overexpression of NOP14 promoted the expression of NRIP1 and phosphorylated inactivation of GSK-3β, leading to the upregulation of β-catenin. Genetic knockdown of NOP14 had the opposite effect on NRIP1/GSK-3/β-catenin signals. NOP14 therefore appears to be overexpressed in clinical samples and cell lines of colorectal cancer, and promotes the proliferation, growth, and metastasis of colorectal cancer cells by modulating the NRIP1/GSK-3β/β-catenin signaling pathway.

Heterogeneous Circulating Tumor Cells in Sarcoma: Implication for Clinical Practice

Simple Summary

The present review is aimed to discuss the relevance of assaying for the presence and isolation of circulating tumor cells (CTCs) in patients with sarcoma. Just a few studies have been performed to detect and enumerate viable CTCs in sarcoma and a majority of them still represent proof-of-concept studies, while more frequently tumor cells have been detected in the circulation by using the PCR-based method. Nevertheless, recent advances in technologies allowed detection of epithelial–mesenchymal transitioned CTCs from patients with mesenchymal malignancies, despite results being mostly preliminary. The possibility to identify CTCs holds a great promise for both applications of liquid biopsy in sarcoma for precision medicine, and for research purposes to pinpoint the mechanism of the metastatic process through the characterization of tumor mesenchymal cells. Coherently, clinical trials in sarcoma have been designed accordingly to detect CTCs, for diagnosis, identification of novel therapeutic targets and resistance mechanisms of systemic therapies, and patient stratification.

Abstract

Bone and soft tissue sarcomas (STSs) represent a group of heterogeneous rare malignant tumors of mesenchymal origin, with a poor prognosis. Due to their low incidence, only a few studies have been reported addressing circulating tumor cells (CTCs) in sarcoma, despite the well-documented relevance for applications of liquid biopsy in precision medicine. In the present review, the most recent data relative to the detection and isolation of viable and intact CTCs in these tumors will be reviewed, and the heterogeneity in CTCs will be discussed. The relevance of epithelial–mesenchymal plasticity and stemness in defining the phenotypic and functional properties of these rare cells in sarcoma will be highlighted. Of note, the existence of dynamic epithelial–mesenchymal transition (EMT)-related processes in sarcoma tumors has only recently been related to their clinical aggressiveness. Also, the presence of epithelial cell adhesion molecule (EpCAM)-positive CTC in sarcoma has been weakly correlated with poor outcome and disease progression, thus proving the existence of both epithelial and mesenchymal CTC in sarcoma. The advancement in technologies for capturing and enumerating all diverse CTCs phenotype originating from these mesenchymal tumors are presented, and results provide a promising basis for clinical application of CTC detection in sarcoma.

Gene Expression Profile and Prognostic Value of m6A RNA Methylation Regulators in Hepatocellular Carcinoma

BACKGROUND

N6-methyladenosine (m6A) RNA methylation is the most prevalent modification of mammalian RNA, and it is associated with tumorigenesis and cancer progression. Its regulation is mediated via m6A-related regulators, including "erasers," "readers," and "writers". The present study evaluated the expression profile, risk signature and prognostic value of 13 m6A regulators in hepatocellular carcinoma (HCC) using different datasets, including The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and clinical samples.

METHODS

We used 374 HCC samples derived from the TCGA database, 569 HCC samples from 2 GEO datasets, and clinical tumour and nontumour tissues derived from 60 patients with HCC who underwent surgery in Xinqiao Hospital Chongqing to assess the gene expression profiles and prognostic values of m6A-related regulators in HCC.

RESULTS

Eight of 13 core m6A-related regulators were overexpressed in all databases, including TCGA, GSE, clinical tumour and nontumour tissues of HCC. Two clusters (Cluster 1 and Cluster 2) were identified via consensus clustering. Cluster 2 was associated with poorer prognosis, higher tumour grade, higher AFP levels, and worse outcome compared to Cluster 1, which indicates that these m6A-related regulators are highly correlated with HCC malignancy. We performed survival analyses using the Log rank tests and a Cox regression model. Gene enrichment analysis was used to detect the related KEGG and GO pathways. We derived a prognostic risk signature using five selected m6A-related regulators.

CONCLUSION

Our work suggested that m6A-related regulators might be key participants in the tumour progression of HCC and potential biomarkers with prognostic value.

Overexpression of chemokine receptor lymphotactin receptor 1 has prognostic value in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is an aggressive subtype of renal cell carcinoma. X‐C motif chemokine receptor 1 (XCR1) exerts important roles in tumor progression; however, its role in ccRCC is unclear.

Methods

We utilized publicly available data from The Cancer Genome Atlas (TCGA) to assess the role of XCR1 in ccRCC and validated the results in 36 samples from patients with ccRCC who underwent curative resection in Xinqiao Hospital Chongqing. XCR1 overexpression was identified in ccRCC, which was confirmed by qRT‐PCR assay and immunohistochemical staining of ccRCC samples.

Results

For the TCGA and clinical data, Kaplan–Meier survival analysis revealed that higher XCR1 expression in ccRCC was related to longer overall survival. Cox regression analysis suggested that XCR1 is an independent risk factor for ccRCC. GSEA analysis suggested that XCR1 is associated with the JAK/STAT signaling pathway. XCR1 knockdown by small interfering RNA (siRNA) significantly increased ccRCC cell proliferation and migration, and decreased cell apoptosis.

Conclusion

We found higher XCR1 expression in ccRCC compared with that in normal tissues is related to longer overall survival in patients with ccRCC. XCR1 knockdown significantly increased RCC cells proliferation and migration, and decreased apoptosis. XCR1 might be used as a prognostic biomarker in ccRCC in the future.

FOXM1/DVL2/Snail axis drives metastasis and chemoresistance of colorectal cancer

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Metastasis and chemoresistance are regarded as the two leading causes of treatment failure and high mortality in CRC. Forkhead Box M1 (FOXM1) has been involved in malignant behaviors of cancer. However, the role and mechanism of FOXM1 in simultaneously regulating metastasis and chemoresistance of CRC remain poorly understood. Here, we found that FOXM1 was overexpressed in oxaliplatin- and vincristine-resistant CRC cells (HCT-8/L-OHP and HCT-8/VCR) with enhanced metastatic potential, compared with HCT-8 cells. FOXM1 overexpression increased migration, invasion and drug-resistance to oxaliplatin and vincristine in HCT-8 cells, while FOXM1 knockdown using shFOXM1 impaired metastasis and drug-resistance in HCT-8/L-OHP and HCT-8/VCR cells. Moreover, FOXM1 up-regulated Snail to trigger epithelial-mesenchymal transition-like molecular changes and multidrug-resistance protein P-gp expression, while silencing Snail inhibited FOXM1-induced metastasis and drug-resistance. We further identified that disheveled-2 (DVL2) was crucial for FOXM1-induced Snail expression, metastasis and chemoresistance. Furthermore, FOXM1 bound to DVL2, and enhanced nuclear translocation of DVL2 and DVL2-mediated transcriptional activity of Wnt/β-catenin known to induce Snail expression. In conclusion, FOXM1/DVL2/Snail axis triggered aggressiveness of CRC. Blocking FOXM1/DVL2/Snail pathway simultaneously inhibited metastasis and chemoresistance in CRC cells, providing a new strategy for successful CRC treatment.

Long intergenic noncoding RNA smad7 (Linc-smad7) promotes the epithelial-mesenchymal transition of HCC by targeting the miR-125b/SIRT6 axis

Long intergenic noncoding RNA smad7 (Linc-smad7) has been recently identified as a new long non-coding RNA (lncRNA). However, the role of Linc-smad7 in the tumourigenesis of human cancers remains unknown. This study uncovered that Linc-smad7 was increased in HCC samples and HCC cell lines using RT-qPCR assays. Furthermore, the overexpression of Linc-smad7 indicated poor clinicopathological features and outcomes for HCC patients. In addition, Linc-smad7 promoted HCC cells proliferation, migration, invasion and EMT, as determined by MTT, colony formation, Transwell assays and western blot analysis. Functionally, it was demonstrated that Linc-smad7 could bind with microRNA-125b (miR-125b), and the restoration of miR-125b rescued the promoting effects of Linc-smad7 on HCC cells. Finally, it was observed that sirtuin 6 (SIRT6) was positively regulated by Linc-smad7 in HCC as the direct target of miR-125b, and decreased SIRT6 reversed the effects of Linc-smad7 on promoting HCC. In conclusion, the current study first identified Linc-smad7 is increased in HCC, facilitating HCC cells proliferation, migration, invasion and EMT via regulating the miR-125b/SIRT6 axis.

High SENP3 Expression Promotes Cell Migration, Invasion, and Proliferation by Modulating DNA Methylation of E-Cadherin in Osteosarcoma

SENP3, a sentrin/SUMO2/3-specific protease, is recognized as a transcriptional factor that accumulates under cellular oxidative stress and plays a significant role in the removal of SUMO2/3 modification. In our study, we examined a TCGA dataset and found that the transcripts per million (TPM) value of SENP3 is high in sarcoma, including osteosarcoma (OS). We found that SENP3 was highly expressed in OS cancer tissues when compared with osteofibrous dysplasia tissues. The survival data of SENP3 in TCGA showed that the sarcoma patients with higher SENP3 expression levels showed poor prognosis. In vitro, SENP3 knockdown in OS cancer cells inhibited cell proliferation, migration, and invasion and induced apoptosis. In contrast, SENP3 overexpression reversed these effects. Next, we found that SENP3 inhibited the expression of E-cadherin (E-Cad) by increasing methylation of the E-Cad promoter. Finally, E-Cad expression was increased in the OS cell line MG63 following methylation, and the cell proliferation, migration, and invasion capacity were decreased. In summary, SENP3 played a significant role in OS carcinogenesis and may act as a potential biomarker in the diagnosis and treatment of OS.

Bone Microenvironment and Osteosarcoma Metastasis

The bone microenvironment is an ideal fertile soil for both primary and secondary tumors to seed. The occurrence and development of osteosarcoma, as a primary bone tumor, is closely related to the bone microenvironment. Especially, the metastasis of osteosarcoma is the remaining challenge of therapy and poor prognosis. Increasing evidence focuses on the relationship between the bone microenvironment and osteosarcoma metastasis. Many elements exist in the bone microenvironment, such as acids, hypoxia, and chemokines, which have been verified to affect the progression and malignance of osteosarcoma through various signaling pathways. We thoroughly summarized all these regulators in the bone microenvironment and the transmission cascades, accordingly, attempting to furnish hints for inhibiting osteosarcoma metastasis via the amelioration of the bone microenvironment. In addition, analysis of the cross-talk between the bone microenvironment and osteosarcoma will help us to deeply understand the development of osteosarcoma. The cellular and molecular protagonists presented in the bone microenvironment promoting osteosarcoma metastasis will accelerate the exploration of novel therapeutic strategies towards osteosarcoma.

Long non-coding RNA PGM5-AS1 promotes epithelial-mesenchymal transition, invasion and metastasis of osteosarcoma cells by impairing miR-140-5p-mediated FBN1 inhibition

Osteosarcoma is an uncommon tumor occurring in bone, accompanied by elevated incidence and reduced rate of healing. Epithelial‐to‐mesenchymal transition (EMT) serves as a conceptual paradigm to explain the invasion and metastasis of osteosarcoma and other cancers. Hence, developing effective therapeutic strategy to treat the EMT of osteosarcoma is essential. Here, we identified the molecular mechanism of long noncoding RNA (lncRNA) PGM5‐AS1 in EMT and progression of osteosarcoma. Microarray‐based analysis was employed to screen the osteosarcoma‐related differentially expressed lncRNAs. The levels of PGM5‐AS1 as well as microRNA‐140‐5p (miR‐140‐5p) and fibrillin‐1 (FBN1) in osteosarcoma tissues and cells were determined. Dual‐luciferase reporter gene assay, RNA pull‐down assay, and RNA immunoprecipitation assay were conducted to validate the relationship among PGM5‐AS1, miR‐140‐5p, and FBN1. Expression of PGM5‐AS1, miR‐140‐5p, and FBN1 was altered by overexpression, shRNA, mimic, or inhibitors in order to investigate how they regulated migration, invasion, and EMT of osteosarcoma cells in vitro. Loss‐ and gain‐of‐function approaches were employed in nude mice to detect their roles in tumorigenesis in vivo. Osteosarcoma tissues and cells exhibited low expression of miR‐140‐5p, but high expression of PGM5‐AS1 and FBN1. PGM5‐AS1 competitively bound to miR‐140‐5p to upregulate FBN1. Furthermore, hindering PGM5‐AS1 and FBN1 or overexpressing miR‐140‐5p dampened migration, invasion, and EMT of osteosarcoma cells in vitro. Furthermore, silencing PGM5‐AS1 or FBN1, or overexpressing miR‐140‐5p markedly inhibited tumorigenesis in nude mice in vivo. Taken together, PGM5‐AS1 depletion causes FBN1 reduction to retard osteosarcoma processes by negatively modulating miR‐140‐5p.

Pediatric sarcomas display a variable EpCAM expression in a histology-dependent manner

EpCAM is a transmembrane glycoprotein typically overexpressed in cancer of epithelial origin and mainly involved in the epithelial-to–mesenchymal transition (EMT) of tumor cells that spread and disseminate. Strategies for the targeting and capture of EpCAM-expressing tumor cells are showing promise in cancers prone to metastatize, both as diagnostic tools and potential therapies. Sarcomas are among the most aggressive tumors in children, with a common mesenchymal origin that comprises both soft tissue sarcomas (STS) and bone sarcomas. The aim of this study was to assess EpCAM expression in pediatric sarcomas and correlate its expression with disease progression. To do so, we analyzed a set of cell lines and primary tumor tissues from rhabdomyosarcoma (RMS), Ewing sarcoma (ES), synovial sarcoma (SS) and desmoplastic small round cell tumor (DSRCT) STS, or osteosarcoma (OS) bone cancer. We demonstrated that EpCAM was variably expressed in pediatric sarcomas, with DSRCT, a rare, aggressive and almost fatal tumor type, characterized by the highest EpCAM expression levels. Interestingly, although EpCAM expression was lower in RMS tumors, high levels at diagnosis correlated with reduced patients' overall survival (p < 0.05). Indeed, membrane-bound EpCAM was detected in circulating sarcoma tumor cells, revealing its potential to be used as dissemination biomarker in this type of childhood cancers. This reinforces the concept that pediatric sarcomas do express both epithelial and mesenchymal markers and reside in an intermediate condition that most likely contributes to their aggressive phenotype and low survival rate.

PHLDA2 regulates EMT and autophagy in colorectal cancer via the PI3K/AKT signaling pathway

High levels of the imprinted gene pleckstrin homology like domain family A member 2 (PHLDA2) correlate with tumor progression in several malignancies. Here, we investigated the effects of PHDLDA2 expression in CRC through assays of cellular proliferation, invasion, migration, and apoptosis. We also screened for possible mechanisms of action. Our results show that PHLDA2 was upregulated in CRC tissues. Knockdown of PHLDA2 inhibited cellular proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT) in vitro. Knockout of PHLDA2 promoted cellular apoptosis, in part by activating autophagy. PHLDA2 knockout also inhibited tumorigenesis and expression of KI67 protein in vivo. The effects of PHLDA2 on autophagy and EMT were mediated in part via the PI3K/AKT signaling pathway. Taken together, these results suggest that downregulation of PHLDA2 inhibits tumor growth and PI3K, thereby promoting autophagy and inhibiting EMT, in part through the PI3K/AKT/mTOR and PI3K/AKT/GSK-3β signaling pathways.

EMT-related gene expression is positively correlated with immunity and may be derived from stromal cells in osteosarcoma

Background

Osteosarcoma is the most common type of bone cancer in children and young adults. Recent studies have shown a correlation between epithelial–mesenchymal transition (EMT)-related gene expression and immunity in human cancers. Here, we investigated the relationship among EMT, immune activity, stromal activity and tumor purity in osteosarcoma.

Methods

We defined EMT gene signatures and evaluated immune activity and stromal activity based on the gene expression and clinical data from three independent microarray datasets. These factors were evaluated by single sample Gene Set Enrichment Analyses and the ESTIMATE tool. Finally, we analyzed the key source of EMT gene expression in osteosarcoma using microarray datasets from the Gene Expression Omnibus and human samples that we collected.

Results

EMT-related gene expression was positively correlated with immune and stromal activity in osteosarcoma. Tumor purity was negatively correlated with EMT, immune activity and stromal cells. We further demonstrated that high EMT gene expression could significantly predict poor overall survival (OS) and recurrence-free survival (RFS) in osteosarcoma patients, while high immune activity cannot. However, combining these factors could have further prognostic value for osteosarcoma patients in terms of OS and RFS. Finally, we found that stromal cells may serve as a key source of EMT gene expression in osteosarcoma.

Conclusion

The results of this study reveal that the expression of EMT genes and immunity are positively correlated, but these signatures convey disparate prognostic information. Furthermore, the results indicate that EMT-related gene expression may be derived from stromal rather than epithelial cancer cells.

Nuclear-localized costimulatory molecule 4-1BBL promotes colon cancer cell proliferation and migration by regulating nuclear Gsk3β, and is linked to the poor outcomes associated with colon cancer

Anti-tumor immune response and the prognosis of tumor are the results of competition between stimulatory and inhibitory checkpoints. Except for upregulating inhibitory checkpoints, lowering some immune accelerating molecules to convert an immunostimulatory microenvironment into an immunodormant one through "decelerating the accelerator" might be another effective immune escape pattern. 4-1BBL is a classical transmembrane costimulatory molecule involving in antitumor immune responses. In contrast, we demonstrated that 4-1BBL is predominantly localized in the nuclei of cancer cells in colon cancer specimens and is positively correlated with tumor size, lymph node metastasis, and a lower survival ratio. Furthermore, the nuclear localization of 4-1BBL was also ascertained in vitro. 4-1BBL knockout (KO) arrests the proliferation and impaired the migration and invasion ability of colon cancer cells in vitro and retarded tumor growth in vivo. 4-1BBL KO increased the accumulation of Gsk3β in the nuclei of colon cancer cells and consequently decreased the expression of Wnt pathway target genes and thus alter tumor biological behavior. We hypothesized that unlike membrane-expressed 4-1BBL, which stimulates the 4-1BB signaling of antitumor cytotoxic T cells, the nuclear-localized 4-1BBL could facilitate the malignant behavior of colon cancer cells by circumventing antitumor signaling and driving some key oncotropic signal pathway in the nucleus. Nuclear-localized 4-1BBL might be an indicator of colon cancer malignancy and serve as a promising target of immunotherapy.

Chaperone mediated detection of small molecule target binding in cells

The ability to quantitatively measure a small molecule’s interactions with its protein target(s) is crucial for both mechanistic studies of signaling pathways and in drug discovery. However, current methods to achieve this have specific requirements that can limit their application or interpretation. Here we describe a complementary target-engagement method, HIPStA (Heat Shock Protein Inhibition Protein Stability Assay), a high-throughput method to assess small molecule binding to endogenous, unmodified target protein(s) in cells. The methodology relies on the change in protein turnover when chaperones, such as HSP90, are inhibited and the stabilization effect that drug-target binding has on this change. We use HIPStA to measure drug binding to three different classes of drug targets (receptor tyrosine kinases, nuclear hormone receptors, and cytoplasmic protein kinases), via quantitative fluorescence imaging. We further demonstrate its utility by pairing the method with quantitative mass spectrometry to identify previously unknown targets of a receptor tyrosine kinase inhibitor.

Quantitative profiling of small molecule-protein binding in cells can aid basic biochemical research and drug discovery. Here, the authors develop the Heat Shock Protein Inhibition Protein Stability Assay (HIPStA) as a high-throughput method to assess cellular target engagement and identify new drug targets.

PD-L1 regulation by SDH5 via β-catenin/ZEB1 signaling

Programmed death-ligand 1 (PD-L1) is a crucial target for lung cancer immunotherapy. In lung cancer patients with high PD-L1 expression, blocking or reducing its expression can inhibit tumor growth. PD-L1 is regulated by signaling pathways, transcription factors and epigenetic factors, such as the GSK3β/β-catenin pathway, P53 protein and EMT. In our previous study, succinate dehydrogenase 5 (SDH5) was reported to regulate ZEB1 expression, induce EMT and lead to lung cancer metastasis via the GSK3β/β-catenin pathway. It is possible that SDH5 is involved in the mechanisms of PD-L1 regulation.In the present study, we observed a negative correlation between the expression of PD-L1 and SDH5 in vivo and in vitro. The examination of patient tissues also confirmed our results. Furthermore, we also found that SDH5 could reverse PD-L1 expression by the GSK3β/β-catenin/ZEB1 pathways. All these results reveal that SDH5 regulates PD-L1 expression and suggest that SDH5 can be used as a marker to predict tumor immune micro-states and provide guidance for clinical immunotherapy.

LncRNA AFAP1-AS1 promotes tumorigenesis and epithelial-mesenchymal transition of osteosarcoma through RhoC/ROCK1/p38MAPK/Twist1 signaling pathway

Background

An increasing number of studies have demonstrated that long non-coding RNAs (lncRNAs) play pivotal roles in cancer onset and development. LncRNA AFAP1-AS1 has been validated to be abnormally upregulated and play oncogenic roles in various malignant tumors. The biological role and mechanism of AFAP1-AS1 in OS (osteosarcoma) remains unclear.

Methods

Quantitative reverse transcription PCR (qRT-PCR) is applied to examine AFAP1-AS1 expression in OS tissues and OS cell lines. The function of AFAP1-AS1 in OS cells is investigated via in-vitro and in-vivo assays. Western bolt and rescue experiments are applied to detect the expression changes of key molecules including epithelial-mesenchymal transition markers and identify the underlying molecular mechanism. RNA immunoprecipitation is performed to reveal the interaction between AFAP1-AS1 and RhoC.

Results

AFAP1-AS1 expression is upregulated in human OS tissues and cell lines. AFAP1-AS1 knockdown induces OS cell apoptosis and cell cycle G0/G1 arrest, suppresses OS cells growth, migration, invasion, vasculogenic mimicry formation and epithelial-mesenchymal transition (EMT), and affects actin filament integrity. AFAP1-AS1 knockdown suppresses OS tumor formation and growth in nude mice. AFAP1-AS1 knockdown elicits a signaling inhibition including decreased levels of RhoC, ROCK1, p38MAPK and Twist1. Moreover, AFAP1-AS1 interacts with RhoC. Overexpression of RhoC can partly reverse AFAP1-AS1 downregulation-induced cell EMT inhibition.

Conclusions

AFAP1-AS1 is overexpressed in osteosarcoma and plays an oncogenic role in osteosarcoma through RhoC/ROCK1/p38MAPK/Twist1 signaling pathway, in which RhoC acts as the interaction target of AFAP1-AS1. Our findings indicated a novel molecular mechanism underlying the tumorigenesis and progression of osteosarcoma. AFAP1-AS1 could serve as a promising therapeutic target in OS treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1363-0) contains supplementary material, which is available to authorized users.

Elevated nuclear auto-antigenic sperm protein promotes melanoma progression by inducing cell proliferation

Background

Nuclear auto-antigenic sperm protein (NASP) has been implicated in tumorigenesis. However, its role in melanoma is still unclear.

Materials and methods

In the present study, we detected the mRNA and protein level of NASP in melanoma cell lines and tissues. Then the role of NASP was investigated by transfecting with NASP siRNAs. Finally, the prognosis of NASP was analyzed in 100 melanoma patients through Cox regression and Kaplan-Meier analyses.

Results

We showed that NASP was significantly overexpressed in melanoma tissues, and unregulated NASP promoted melanoma cell proliferation via promoting cell cycle G1/S phase transition. Additionally, the expression of NASP was closely related to proliferating cell nuclear antigen, a widely accepted biomarker for cell proliferation. Clinically, we found that a high level of NASP predicated poor overall survival and high cumulative recurrence rates. Multivariate analysis revealed that NASP was a risk biomarker for predicting the prognosis of melanoma patients.

Conclusion

Elevated NASP plays an important role in melanoma cell proliferation and tumor progression, and it can be used as an independent prognostic biomarker for melanoma patients.

Overexpression of Notch3 is associated with metastasis and poor prognosis in osteosarcoma patients

Background

Notch signaling abnormalities are associated with the development of various tumors, including hematopoietic and epithelium-derived tumors. However, the role of Notch signaling in tumors originating from mesenchymal cells is unclear. The effect of Notch3 expression on the prognosis of osteosarcoma and its role and mechanism in osteosarcoma cells have never been reported.

Materials and methods

In this study, we performed a clinicopathological analysis of 70 cases of osteosarcoma, with primary focus on survival. Osteosarcoma cell lines MTH and U2OS were used. After knockdown of Notch3 by lentiviral transfection and siRNA, the cell cycle, cell viability, and wound healing capacity were assessed. Subsequently, the Transwell assay was performed, and the expression levels of hairy and enhancer of split-1 (Hes1) and matrix metalloproteinase 7 (MMP7) were detected by RT-PCR and Western blot assay. The expression of MMP7 was also detected after knockdown of Hes1. Animal experiments were performed by injecting the cell lines MTH of Notch3 knockdown into mice tail veins and comparing the development of lung metastasis with the control group.

Results

Comparison of survival curves showed that Notch3 expression significantly impacts patient survival. Additionally, multivariate analysis revealed that Notch3 is an independent prognostic factor for osteosarcoma. In in vivo experiments, osteosarcoma-associated pulmonary metastasis in nude mice was reduced after Notch3 silencing. The expression of downstream effector molecule, Hes1, and that of the invasion and metastasis-associated proteolytic enzyme, MMP7, were reduced, and MMP7 was further decreased by Hes1 knockdown in in vitro experiments.

Conclusion

Notch3 is a prognostic factor for osteosarcoma and might regulate its invasion and metastasis through the downstream target gene Hes1 and effector MMP7.

miR-222-3p promotes osteosarcoma cell migration and invasion through targeting TIMP3

BACKGROUND

Abnormal expression of miRNAs has been reported in osteosarcoma (OS), and miR-222-3p levels have been found to be increased in the serum of OS patients. However, the exact role of miR-222-3p in OS remains unclear. In the present study, we aimed to identify the molecular mechanism underlying the role of miR-222-3p in the development of OS.

METHODS

We examined the expression level of miR-222-3p in OS tissues and OS cells using reverse-transcription quantitative PCR (RT-qPCR) analysis. MTT, colony formation, and transwell invasion assays were used to analyze the effects of miR-222-3p on the proliferation and invasion ability of OS cells. Luciferase reporter gene assays were used to confirm the target gene of miR-222-3p in OS cells. Tumor xenografts were then used to investigate the role of miR-222-3p in OS growth in vivo.

RESULTS

The data of the present study demonstrated that miR-222-3p levels were increased in OS tissues and OS cells. Downregulation of miR-222-3p significantly inhibited the proliferation, migration, and invasion of OS cells in vitro. Further analysis revealed that tissue inhibitors of metalloproteinases 3 (TIMP3) is one of the functional target genes of miR-222-3p, and inhibition of TIMP3 efficiently rescues the blocking of cell proliferation and invasion mediated by miR-222-3p inhibitor in OS cells.

CONCLUSION

Our findings constitute evidence that miR-222-3p promotes OS cell proliferation and invasion through targeting TIMP3 mRNA and provide novel insight into the mechanism underlying the development of OS.

Epigenetic silencing of SFRP5 promotes the metastasis and invasion of chondrosarcoma by expression inhibition and Wnt signaling pathway activation

BACKGROUD/AIMS

Abnormal activation of the Wnt/β-catenin signaling, which may be antagonized by the members of secreted frizzled-related proteins family (SFRPs), is implicated in tumor occurrence and development. However, the function of SFRP5 relating to Wnt/β-catenin pathway in chondrosarcoma is not clear yet. This study was undertaken to investigate the potential role of SFRP5 promoter methylation in chondrosarcoma metastasis and invasion through activating canonical Wnt signaling pathway.

METHODS AND RESULTS

The results demonstrated that SFRP5 promoter was hypermethylated and SFRP5 expression was significantly reduced in chondrosarcoma cell lines at the mRNA and protein levels. The canonical Wnt/β-catenin signaling was observably activated with β-catenin stabilization by dephosphorylation and translocation into the nuclear. 5-Aza-2'-deoxycytidine (5-Aza-dC), the DNA methyltransferase inhibitor, significantly inhibited the proliferation of chondrosarcoma cells by cell cycle arrest through repressing the methylation of SFRP5 and promoting its expression. Both 5-Aza-dC treatment and SFRP5 overexpression could significantly inhibited the metastasis and invasion of chondrosarcoma cells by inactivating Wnt/β-catenin signaling pathway and promoting chondrosarcoma cells mesenchymal-epithelial transition (MET). 5-Aza-dC also inhibited the xenograft growth and lung metastasis of chondrosarcoma cells in vivo via suppressing SFRP5 promotor methylation, inactivating Wnt/β-catenin pathway and inducing epithelial markers expression.

CONCLUSION

All of our results revealed the epigenetic silencing of SFRP5 by promoter methylation plays pivotal roles in chondrosarcoma development and metastasis through SFRP5/Wnt/β-catenin signaling axis. Modulation of their levels may serve as potential targets and diagnostic tools for novel therapeutic strategies of chondrosarcoma.

TSSC3 promotes autophagy via inactivating the Src-mediated PI3K/Akt/mTOR pathway to suppress tumorigenesis and metastasis in osteosarcoma, and predicts a favorable prognosis

BACKGROUND

Over the last two or three decades, the pace of development of treatments for osteosarcoma tends has been slow. Novel effective therapies for osteosarcoma are still lacking. Previously, we reported that tumor-suppressing STF cDNA 3 (TSSC3) functions as an imprinted tumor suppressor gene in osteosarcoma; however, the underlying mechanism by which TSSC3 suppresses the tumorigenesis and metastasis remain unclear.

METHODS

We investigated the dynamic expression patterns of TSSC3 and autophagy-related proteins (autophagy related 5 (ATG5) and P62) in 33 human benign bone tumors and 58 osteosarcoma tissues using immunohistochemistry. We further investigated the correlations between TSSC3 and autophagy in osteosarcoma using western blotting and transmission electronic microscopy. CCK-8, Edu, and clone formation assays; wound healing and Transwell assays; PCR; immunohistochemistry; immunofluorescence; and western blotting were used to investigated the responses in TSSC3-overexpressing osteosarcoma cell lines, and in xenografts and metastasis in vivo models, with or without autophagy deficiency caused by chloroquine or ATG5 silencing.

RESULTS

We found that ATG5 expression correlated positively with TSSC3 expression in human osteosarcoma tissues. We demonstrated that TSSC3 was an independent prognostic marker for overall survival in osteosarcoma, and positive ATG5 expression associated with positive TSSC3 expression suggested a favorable prognosis for patients. Then, we showed that TSSC3 overexpression enhanced autophagy via inactivating the Src-mediated PI3K/Akt/mTOR pathway in osteosarcoma. Further results suggested autophagy contributed to TSSC3-induced suppression of tumorigenesis and metastasis in osteosarcoma in vitro and in vivo models.

CONCLUSIONS

Our findings highlighted, for the first time, the importance of autophagy as an underlying mechanism in TSSC3-induced antitumor effects in osteosarcoma. We also revealed that TSSC3-associated positive ATG5 expression might be a potential predictor of favorable prognosis in patients with osteosarcoma.

Identification of two potential glycogen synthase kinase 3β inhibitors for the treatment of osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor among adolescents worldwide with high mortality rate. Glycogen synthase kinase 3β (GSK3β) is a serine/threonine kinase and is considered as a validated target in osteosarcoma therapy. Therefore, the study of GSK3β inhibitors is one of the most popular fields in anti-osteosarcoma drug development. Here, the tools of bioinformatics were used to screen novel effective inhibitors of GSK3β from ZINC Drug Database. The molecular docking, molecular dynamic simulations, MM/GBSA, and energy decomposition analysis were performed to identify the inhibitors. Finally, ZINC08383479 and ZINC08441251 were selected as potential GSK3β inhibitors. These two inhibitors were evaluated by GSK3β kinase inhibition assay in vitro. The inhibition of cell proliferation was tested in osteosarcoma cell lines U2OS and MG63 in vitro. The result showed that ZINC08383479 and ZINC08441251 had high inhibition activity against GSK3β. We found that CHIR99021 (a known GSK3β inhibitor), ZINC08383479, and ZINC08441251 had significant inhibition activity in U2OS cells and MG63 cells. These findings may provide new ideas for the design of more potent GSK3β inhibitors and therapeutic targets for osteosarcoma.

Employing an orthotopic model to study the role of epithelial-mesenchymal transition in bladder cancer metastasis

Epithelial-to-mesenchymal transition (EMT) has been implicated in the progression of bladder cancer. To study its contribution to bladder cancer metastasis, we established new xenograft models derived from human bladder cancer cell lines utilizing an orthotopic “recycling” technique that allowed us to isolate and examine the primary tumor and its corresponding circulating tumor cells (CTC’s) and metastatic lesions. Using whole genome mRNA expression profiling, we found that a reversible epithelial-to-mesenchymal transition (EMT) characterized by TGFβ pathway activation and SNAIL expression was associated with the accumulation of CTCs. Finally, we observed that conditional silencing of SNAIL completely blocked CTC production and regional/distant metastasis. Using this unique bladder cancer xenograft model, we conclude that metastasis is dependent on a reversible EMT mediated by SNAIL.

miR-27a-3p promotes the malignant phenotypes of osteosarcoma by targeting ten-eleven translocation 1

Osteosarcoma has become one of the most common primary malignant tumors affecting children and adolescents. Although increasing evidence has indicated that microRNAs (miRNAs or miRs) play important roles in the development of osteosarcoma, the expression of miR‑27a‑3p and its effects on osteosarcoma are not yet fully understood. In the present study, our data demonstrated that the expression of miR‑27a‑3p in osteosarcoma cell lines was significantly higher than that in the normal human osteoblastic cell line, hFOB 1.19 cell (P<0.01). In order to explore the role of miR‑27a‑3p in the development and progression of osteosarcoma, the expression of miR‑27a‑3p was inhibited by transfection of the MG-63 cells with miR‑27a‑3p inhibitor. The results revealed that the cell proliferative ability significantly decreased (P<0.01), the number of apoptotic cells significantly increased (P<0.01) and the number of cells passing through the Transwell membrane was significantly reduced in the group transfected with the miR‑27a‑3p inhibitor (P<0.01). At the same time, the expression of E-cadherin and α-catenin was significantly upregulated (P<0.01), while the expression of vimentin was significantly downregulated in the group transfected with the miR‑27a‑3p inhibitor (P<0.01). Our results also revealed that the mRNA expression of ten-eleven translocation 1 (TET1) in the osteosarcoma cells was significantly downregulated compared with that in the hFOB 1.19 cells (P<0.01). Luciferase reporter system analysis indicated that miR‑27a‑3p recognized the TET1 3'-UTR. The protein expression of TET1 significantly increased in the group transfected with the miR‑27a‑3p inhibitor. The results from CCK-8 assay, flow cytometric assay and Transwell invasion analysis revealed that TET1 knockdown inhibited the biological effects induced by the downregulation of miR‑27a‑3p. Taken together, the findings of this study indicate that miR‑27a‑3p is upregulated, while TET1 is downregulated in human osteosarcoma cells. miR‑27a‑3p inhibition suppresses the proliferation and invasion of osteosarcoma cells, and promotes cell apoptosis via the negative regulation of TET1. miR‑27a‑3p/TET1 may thus be a potential target for the treatment of osteosarcoma.

EGFR is involved in dermatofibrosarcoma protuberans progression to high grade sarcoma

Dermatofibrosarcoma protuberans (DFSP), amounting to 6% of all soft tissue sarcomas, has a slow growth rate, contrasting with a likelihood for local recurrence and a 10-20% evolution to higher-grade sarcoma, or "transformed DFSP" (DFSP-T). At molecular level, the characteristic COL1A1-PDGFB rearrangement, leading to sustained PDGFR signaling, is not linked to the evolutive potential. Here, we studied EGFR, another tyrosine kinase receptor, using laser-microdissection to select the different histologic components of DFSP (DFSP center, DFSP infiltrative periphery, DFSP-T higher-grade sarcoma), in 22 patients followed over 3 to 156 months. EGFR protein and mRNA were expressed in 13/22 patients with DFSP or DFSP-T, and increased with tumor progression, both in microdissected areas of higher-grade sarcomas and in microdissected areas of local extension. No cancer-associated EGFR gene mutation or copy-number variation, nor any KRAS, BRAF, NRAS hotspot mutations were found in any microdissected area. Among epithelial-mesenchymal transition factors tested, SNAIL 1/2 had the same expression pattern as EGFR while ZEB1/2 or TWIST1/2 did not. Using a proteome profiler phospho-kinase array on 3 DFSP and 3 DFSP-T cryopreserved tissue samples, EGFR phosphorylation was detected in each case. Among EGFR downstream pathways, we found positive correlations between phosphorylation levels of EGFR and STAT5a/b (r = 0.87, p < 0.05) and TOR (r = 0.95, p < 0.01), but not ERK in the MAPK pathway (r = -0.18, p > 0.70). We thus demonstrated that in DFSP evolution to high grade sarcoma, EGFR and SNAIL were involved, with EGFR activation and signaling through TOR and STAT5a/b downstream effectors, which could lead on to new therapies for advanced DFSP.

Cytosolic THUMPD1 promotes breast cancer cells invasion and metastasis via the AKT-GSK3-Snail pathway

Human THUMP domain-containing protein 1 (THUMPD1) is a specific adaptor protein that modulates tRNA acetylation through interaction with NAT10. Immunohistochemical analysis of 146 breast cancer specimens (82 triple-negative and 64 non-triple-negative cases) indicated THUMPD1 expression is higher in breast cancer tissues (60.9%, 89/146) than normal breast tissues (28.3%, 15/53; p < 0.001). Overall and cytosolic, but not nuclear, THUMPD1 expression in breast cancer correlated with advanced TNM stage (p = 0.003 and p < 0.001, respectively), lymph node metastasis (p = 0.001 and p < 0.001, respectively), and poor patient prognosis (p = 0.001 and p < 0.001, respectively). THUMPD1 interacted and co-localized with YAP, but did not affect Hippo pathway activity. THUMPD1 overexpression enhanced breast cancer cells invasion and migration in vivo and in vitro, possibly through activation of AKT, GSK3β and Snail, and inhibition of E-cadherin. Treatment with the AKT inhibitor, LY294002, reduced the effects of THUMPD1 overexpression in breast cancer cells. These results indicate that THUMPD1 promotes breast cancer cells invasion and migration via the AKT-GSK3β-Snail pathway.

Epithelial-to-Mesenchymal and Mesenchymal-to-Epithelial Transition in Mesenchymal Tumors: A Paradox in Sarcomas?

The epithelial-to-mesenchymal transition (EMT) is a reversible process comprised of various subprograms via which epithelial cells reduce their intercellular adhesions and proliferative capacity while gaining a mesenchymal phenotype with increased migratory and invasive properties. This process has been well described in several carcinomas, which are cancers of epithelial origin, and is crucial to metastatic tumor cell dissemination and drug resistance. In contrast, the precise role of EMT-related processes in tumors originating from mesenchymal tissues, such as bone and soft-tissues sarcomas, is still largely unclear. In fact, although the existence of the EMT in sarcomas appears paradoxical because these cancers are, by definition, mesenchymal ab initio, accumulating evidence suggests that many sarcomas can undergo EMT-related processes, which may be associated with aggressive clinical behavior. These processes may be especially operative in certain sarcoma subtypes, such as carcinosarcomas displaying a biphenotypic morphology with characteristics of both mesenchymal and epithelial tumors. In this review, we discuss findings regarding the potential existence of EMT-related processes in sarcomas and propose that sarcomas can reside in a metastable state, enabling them to become either more mesenchymal or epithelial under specific conditions, which likely has important clinical implications. Cancer Res; 77(17); 4556-61. ©2017 AACR.

Wnt3a Expression Is Associated with Epithelial-Mesenchymal Transition and Impacts Prognosis of Lung Adenocarcinoma Patients

Background: Epithelial-mesenchymal transition (EMT) plays an important role in the invasion and migration during cancer metastasis. Wnt3a is one of the ligands in canonical Wnt/β-catenin signaling pathway, which contributes to the carcinogenesis and progression of lung cancer cell lines. The aim of this study was to evaluate the association between Wnt3a and EMT-related proteins (E-cadherin and N-cadherin), and to further investigate its impact on prognosis of lung adenocarcinoma patients. Methods: A total of 147 lung adenocarcinoma patients were included and their clinicopathological characteristics were collected in this retrospective study. The expression levels of Wnt3a, E-cadherin and N-cadherin in post-surgery cancerous and adjacent normal tissues were assessed by immunohistochemistry. The association between Wnt3a and EMT-related proteins and their prognostic values were systematically evaluated. HCC827 and PC9 cell lines were treated with Wnt3a to detect the expression of EMT-related and Wnt/β-catenin signaling-associated proteins, as well as the in vitro migration and invasion abilities. Results: High Wnt3a expression level was significantly associated with low E-cadherin (P<0.001) and high N-cadherin (P<0.001) expression levels in lung adenocarcinoma tissues. Besides, high Wnt3a level predicted poorer lung adenocarcinoma survival by univariate Cox analysis (P=0.001), while the multivariate result was not significant (P=0.355). Subgroup analysis suggested that the prognostic value of Wnt3a expression level was significant in stage T1-T2 (log rank P=0.003) and stage N0 (log rank P=0.031) patients. The multivariate Cox analysis suggested N-cadherin was an independent prognostic factor for lung adenocarcinoma patients (P=0.012). After including these markers into a nomogram, the Harrell's C-index of the nomogram was 0.755. The decision-curve analysis of our nomogram performed net benefit at the threshold probability from 21.6% to 82.0%, and the current model had a better prognostic value than TNM-classification with a lower Akaike information criterion (AIC) value of 166.54. In vitro experiments suggested that Wnt3a could regulate EMT-related proteins and promotes in vitro invasion and migration abilities. Conclusions: Wnt3a could regulate EMT-related proteins and promote the migration and invasion process of lung adenocarcinoma. Although its value as an independent prognostic factor was limited, the combined model suggested good prognostic performance for lung adenocarcinoma patients.

High expression of TRIM29 (ATDC) contributes to poor prognosis and tumor metastasis by inducing epithelial‑mesenchymal transition in osteosarcoma

The association of TRIM29 overexpression with cancer progression and poor clinical prognosis has been reported in the context of several types of cancers. In the present study, we investigated the prognostic relevance of TRIM29 and its involvement in the progression of human osteosarcoma. To the best of our knowledge, this is the first study to demonstrate a major role of TRIM29 in osteosarcoma. Our results showed that the expression of TRIM29 in osteosarcoma tissues was much higher than that in normal bone tissues. Furthermore, TRIM29 expression was significantly correlated with tumor size, recurrence, metastasis and overall survival time. High expression of TRIM29 and presence of metastasis were independent predictors of poor prognosis in these patients. Both protein and mRNA expression of TRIM29 in osteosarcoma cell lines were significantly higher than those in osteoblast cell line, hFOB1.19. Moreover, the results indicated that TRIM29 promoted migration and invasive growth of osteosarcoma cells by inducing epithelial-mesenchymal transition. Therefore, ectopic expression of TRIM29 potentially contributes to metastasis and poor prognosis in patients with osteosarcoma. In summary, TRIM29 is a potential prognostic biomarker and a therapeutic target for patients with osteosarcoma.

Sex-determining region Y-box protein 3 induces epithelial-mesenchymal transition in osteosarcoma cells via transcriptional activation of Snail1

Background

The transcription factor sex-determining region Y-box protein 3 (SOX3) plays important roles in various types of cancer. However, its expression and function have not yet been elucidated in osteosarcoma (OS).

Methods

The expression levels of SOX3 in OS tissues and OS cell lines were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. The effects of SOX3 expression on OS cell biological traits were investigated by overexpressing and downregulating SOX3 protein. The expression of epithelial-mesenchymal transition (EMT) markers and transcription factors associated with EMT (EMT-TFs), were detected simultaneously. The mechanism underlying SOX3-mediated Snail1 expression was further investigated.

Results

SOX3 was upregulated in human OS tissues. SOX3 overexpression promoted the EMT, migration and invasion in OS cells. The downregulation of SOX3 resulted in opposing effects. Furthermore, SOX3 upregulation enhanced the expression of the transcriptional repressor Snail1 by binding to its promoter region. Additionally, a positive correlation among the expression of SOX3, Snail1, and E-cadherin was demonstrated in human OS tissues.

Conclusions

SOX3 promotes migration, invasiveness, and EMT in OS cells via transcriptional activation of Snail1 expression, suggesting that SOX3 is a novel regulator of EMT in OS and may serve as a therapeutic target for the treatment of OS metastasis.

Correlations Between Hector Battifora Mesothelial-1 (HBME-1) Expression and Clinical Pathological Characteristics and Prognosis of Osteosarcoma Patients

Background

The aim of this study was to investigate the correlation between Hector Battifora mesothelial-1 (HBME-1) expression and the clinical pathological characteristics and prognosis of osteosarcoma (OS).

Material/Methods

HBME-1 expression was assessed using immunohistochemistry in OS tissues (n=152), osteochondroma tissues (n=91), and normal bone tissues (n=74). We carried out a follow-up lasting 8–60 months to investigate HBME-1 expression and its correlations with the clinical pathological characteristics and prognosis of OS.

Results

HBME-1 was highly expressed in OS tissues compared with osteochondroma tissues and normal bone tissues, and was highly expressed in osteochondroma tissues compared with normal bone tissues (all P<0.05). HBME-1 expression was correlated with clinical stages, postoperative recurrence, metastasis, and 5-year survival (all P<0.05). The area under the receiver operating characteristics curve of HBME-1 expression was 0.864, with sensitivity of 80.92%, specificity of 91.89%, and accuracy of 84.51%. The survival rate was lower in the HBME-1 positive expression group than the HBME-1 negative expression group (P<0.05). Clinical stages, metastasis, and HBME-1 expression were independent risk factors for the survival of patients with OS (all P<0.05).

Conclusions

HBME-1 expression was correlated with the occurrence and development of OS. HBME-1 positive expression was a risk factor for the prognosis of OS.