Effects of long-term low oxygen tension in human chondrosarcoma cells

Quantitative proteomics combined independent PRM analysis reveals the mitochondrial and synaptic mechanism underlying norisoboldine's antidepressant effects

Major depressive disorder (MDD) is a common disease affecting 300 million people worldwide. The existing drugs are ineffective for approximately 30% of patients, so it is urgent to develop new antidepressant drugs with novel mechanisms. Here, we found that norisoboldine (NOR) showed an antidepressant efficacy in the chronic social defeat stress (CSDS) depression model in the tail suspension, forced swimming, and sucrose consumption tests. We then utilized the drug-treated CSDS mice paradigm to segregate and gain differential protein groups of CSDS versus CON (CSDSCON), imipramine (IMI)-treated versus CSDS (IMICSDS), and NOR-treated versus CSDS (NORCSDS) from the prefrontal cortex. These protein expression alterations were first analyzed by ANOVA with p < 0.05. The protein cluster 1 and cluster 3, in which the pattern of protein levels similar to the mood pattern, showed enrichment in functions and localizations related to mitochondrion, ribosome and synapses. Further GO analysis of the common proteins for NORCSDS groups and NORIMI groups supported the findings from ANOVA analysis. We employed Protein-Protein interaction (PPI) analysis to examine the proteins of NORCSDS and NORIMI, revealing an enrichment of the proteins associated with the mitochondrial ribosomal and synaptic functions. Further independent analysis using parallel reaction monitoring (PRM) revealed that Cox7c, Mrp142, Naa30, Ighm, Apoa4, Ssu72, Mrps30, Apoh, Acbd5, and Cdv3, exhibited regulation in the NOR-treated group to support the homeostasis of mitochondrial functions. Additionally, Dcx, Arid1b, Rnf112, and Fam3c, were also observed to undergo modulation in the NOR-treated groups to support the synaptic formation and functions. These findings suggest that the proteins involved in depression treatment exert effects in strengthen the mitochondrial and synaptic functions in the mice PFC. Western blot analysis supported the data that the levels of Mrpl42, Cox7c, Naa30, Rnf112, Dcx Apoa4, Apoh and Fam3c were altered in the CSDS mice, and rescued by NOR treatment, supporting the PRM data. NOR treatment also rescued the NLRP3 inflammasome activation in CSDS mice. In summary, the current proteomic research conducted on the prefrontal cortex has provided valuable insights into the specific and shared molecular mechanisms underlying pathophysiology and treatment to CSDS-induced depression, shedding light on the therapeutic effects of Norisoboldine.

Regulation of Oxygen Tension as a Strategy to Control Chondrocytic Phenotype for Cartilage Tissue Engineering and Regeneration

Cartilage defects and osteoarthritis are health problems which are major burdens on health care systems globally, especially in aging populations. Cartilage is a vulnerable tissue, which generally faces a progressive degenerative process when injured. This makes it the 11th most common cause of global disability. Conservative methods are used to treat the initial phases of the illness, while orthopedic management is the method used for more progressed phases. These include, for instance, arthroscopic shaving, microfracturing and mosaicplasty, and joint replacement as the final treatment. Cell-based implantation methods have also been developed. Despite reports of successful treatments, they often suffer from the non-optimal nature of chondrocyte phenotype in the repair tissue. Thus, improved strategies to control the phenotype of the regenerating cells are needed. Avascular tissue cartilage relies on diffusion for nutrients acquisition and the removal of metabolic waste products. A low oxygen content is also present in cartilage, and the chondrocytes are, in fact, well adapted to it. Therefore, this raises an idea that the regulation of oxygen tension could be a strategy to control the chondrocyte phenotype expression, important in cartilage tissue for regenerative purposes. This narrative review discusses the aspects related to oxygen tension in the metabolism and regulation of articular and growth plate chondrocytes and progenitor cell phenotypes, and the role of some microenvironmental factors as regulators of chondrocytes.

Beyond MitoCarta-expanding the list of candidate proteins involved in mitochondrial functions using a biological network approach

Mitochondrial diseases are the result of pathogenic variants in genes involved in the diverse functions of the mitochondrion. A comprehensive list of mitochondrial genes is needed to improve gene prioritization in the diagnosis of mitochondrial diseases and development of therapeutics that modulate mitochondrial function. MitoCarta is an experimentally derived catalog of proteins localized to mitochondria. We sought to expand this list of mitochondrial proteins to identify proteins that may not be localized to the mitochondria yet perform important mitochondrial functions. We used a computational approach to assign statistical significance to the overlap between STRING database gene network neighborhoods and MitoCarta proteins. Using a data-driven stringent significance threshold, 2059 proteins that were not located in MitoCarta were identified, which we termed mitochondrial proximal (MitoProximal) proteins. We identified all of the oxidative phosphorylation complex subunits and 90% of 149 genes that contain confirmed oxidative phosphorylation disease causal variants, lending validation to our methodology. Among the MitoProximal proteins, 134 are annotated to be localized to mitochondria but are not in the MitoCarta 3.0 database. We extend MitoCarta nearly 3-fold, generating a more comprehensive list of mitochondrial genes, a resource to facilitate the identification of pathogenic variants in mitochondrial and metabolic diseases.

The Role of IGF/IGF-IR-Signaling and Extracellular Matrix Effectors in Bone Sarcoma Pathogenesis

Simple Summary

Bone sarcomas are mesenchymal origin tumors. Bone sarcoma patients show a variable response or do not respond to chemotherapy. Notably, improving efficient chemotherapy approaches, dealing with chemoresistance, and preventing metastasis pose unmet challenges in sarcoma therapy. Insulin-like growth factors 1 and 2 (IGF-1 and -2) and their respective receptors are a multifactorial system that significantly contributes to bone sarcoma pathogenesis. Most clinical trials aiming at the IGF pathway have had limited success. Developing combinatorial strategies to enhance antitumor responses and better classify the patients that could best benefit from IGF-axis targeting therapies is in order. A plausible approach for developing a combinatorial strategy is to focus on the tumor microenvironment (TME) and processes executed therein. Herewith, we will discuss how the interplay between IGF-signaling and the TME constituents affects bone sarcomas’ basal functions and their response to therapy. Potential direct and adjunct therapeutical implications of the extracellular matrix (ECM) effectors will also be summarized.

Abstract

Bone sarcomas, mesenchymal origin tumors, represent a substantial group of varying neoplasms of a distinct entity. Bone sarcoma patients show a limited response or do not respond to chemotherapy. Notably, developing efficient chemotherapy approaches, dealing with chemoresistance, and preventing metastasis pose unmet challenges in sarcoma therapy. Insulin-like growth factors 1 and 2 (IGF-1 and -2) and their respective receptors are a multifactorial system that significantly contributes to bone sarcoma pathogenesis. Whereas failures have been registered in creating novel targeted therapeutics aiming at the IGF pathway, new agent development should continue, evaluating combinatorial strategies for enhancing antitumor responses and better classifying the patients that could best benefit from these therapies. A plausible approach for developing a combinatorial strategy is to focus on the tumor microenvironment (TME) and processes executed therein. Herewith, we will discuss how the interplay between IGF-signaling and the TME constituents affects sarcomas’ basal functions and their response to therapy. This review highlights key studies focusing on IGF signaling in bone sarcomas, specifically studies underscoring novel properties that make this system an attractive therapeutic target and identifies new relationships that may be exploited. Potential direct and adjunct therapeutical implications of the extracellular matrix (ECM) effectors will also be summarized.

NDUFA4L2 Regulated by HIF-1α Promotes Metastasis and Epithelial-Mesenchymal Transition of Osteosarcoma Cells Through Inhibiting ROS Production

Osteosarcoma (OS) accounts for a large proportion of the types of bone tumors that are newly diagnosed, and is a relatively common bone tumor. However, there are still no effective treatments for this affliction. One interesting avenue is related to the mitochondrial NDUFA4L2 protein, which is encoded by the nuclear gene and is known to be a critical mediator in the regulation of cell survival. Thus, in this study, we aimed to investigate the effect of NDUFA4L2 upon the metastasis and epithelial–mesenchymal transition of OS. We found that NDUFA4L2 protein expression was upregulated in hypoxic conditions. We also used 2-ME and DMOG, which are HIF-1α inhibitors and agonists, respectively, to assess the effects related to decreasing or increasing HIF-1α expression. 2-ME caused a significant decrease of NDUFA4L2 expression and DMOG had the opposite effect. It was obvious that down-regulation of NDUFA4L2 had a direct interaction with the apoptosis of OS cells. Western blotting, wound healing analyses, Transwell invasion assays, and colony formation assays all indicated and supported the conclusion that NDUFA4L2 promoted OS cell migration, invasion, proliferation, and the epithelial–mesenchymal transition. During experiments, we incidentally discovered that autophagy and the ROS inhibitor could be used to facilitate the rescuing of tumor cells whose NDUFA4L2 was knocked down. Our findings will help to further elucidate the dynamics underlying the mechanism of OS cells and have provided a novel therapeutic target for the treatment of OS.

Cardiac Transcriptomics Reveals That MAPK Pathway Plays an Important Role in Hypoxia Tolerance in Bighead Carp (Hypophthalmichthys nobilis)

As aquatic animals, fishes often encounter various situations of low oxygen, and they have evolved the ability to respond to hypoxia stress. Studies of physiological and molecular responses to hypoxia stress are essential to clarify genetic mechanisms underlying hypoxia tolerance in fish. In this study, we performed acute hypoxia treatment in juvenile bighead carp (Hypophthalmicthys nobilis) by decreasing water O₂ from 6.5 mg/L to 0.5 mg/L in three hours. This hypoxia stress resulted in a significant increase in blood lactate and serum glucose. Comparisons of heart transcriptome among hypoxia tolerant (HT), hypoxia sensitive (HS), and normoxia control (NC) groups showed that 820, 273, and 301 differentially expressed genes (DEGs) were identified in HS vs. HT, NC vs. HS, and NC vs. HT (false discovery rate (FDR) < 0.01, Fold Change> 2), respectively. KEGG pathway enrichment showed that DEGs between HS and HT groups were mainly involved in mitogen-activated protein kinase (MAPK) signaling, insulin signaling, apoptosis, tight junction and adrenergic signaling in cardiomyocytes pathways, and DEGs in MAPK signaling pathway played a key role in cardiac tolerance to hypoxia. Combined with the results of our previous cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis of hypoxia stress in this species, such genes as stbp2, ttn, mapk, kcnh, and tnfrsf were identified in both studies, representing the significance of these DEGs in hypoxia tolerance in bighead carp. These results provide insights into the understanding of genetic modulations for fish heart coping with hypoxia stress and generate basic resources for future breeding studies of hypoxia resistance in bighead carp.

Coxfa4l3, a novel mitochondrial electron transport chain Complex 4 subunit protein, switches from Coxfa4 during spermatogenesis

We identified Coxfa4l3, previously called C15orf48 or Nmes1, as a novel accessory protein of Complex IV of the mitochondrial electron transport chain (ETC). Amino acid sequence comparison, the intracellular localization and the protein expression data showed that the protein is the third isoform of Coxfa4 and the expression of Coxfa4 and Coxfa4l3 proteins during spermatogenesis showed a mutually exclusive pattern, implying that Coxfa4 replaces Coxfa4l3 in Complex IV after meiosis. These results may provide some insight into the unique mechanism of ATP production in late spermatogenesis.

Integrating transcriptome-wide study and mRNA expression profiles yields novel insights into the biological mechanism of chondropathies

Background

Chondropathies are a group of cartilage diseases, which share some common pathogenetic features. The etiology of chondropathies is still largely obscure now.

Methods

A transcriptome-wide association study (TWAS) was performed using the UK Biobank genome-wide association study (GWAS) data of chondropathies (including 1314 chondropathy patients and 450,950 controls) with gene expression references of muscle skeleton (MS) and peripheral blood (YBL). The candidate genes identified by TWAS were further compared with three gene expression profiles of osteoarthritis (OA), cartilage tumor (CT), and spinal disc herniation (SDH), to confirm the functional relevance between the chondropathies and the candidate genes identified by TWAS. Functional mapping and annotation (FUMA) was used for the gene ontology enrichment analyses. Immunohistochemistry (IHC) was conducted to validate the accuracy of integrative analysis results.

Results

Integrating TWAS and mRNA expression profiles detected 84 candidate genes for knee OA, such as DDX20 (P_{TWAS YBL} = 1.79 × 10^− 3, fold change (FC) = 2.69), 10 candidate genes for CT, such as SRGN (P_{TWAS YBL} = 1.46 × 10^− 3, FC = 3.36), and 4 candidate genes for SDH, such as SUPV3L1 (P_{TWAS YBL} = 3.59 × 10^− 3, FC = 3.22). Gene set enrichment analysis detected 73 GO terms for knee OA, 3 GO terms for CT, and 1 GO term for SDH, such as mitochondrial protein complex (P = 7.31 × 10^− 5) for knee OA, cytokine for CT (P = 1.13 × 10^− 4), and ion binding for SDH (P = 3.55 × 10^− 4). IHC confirmed that the protein expression level of DDX20 was significantly different between knee OA cartilage and healthy control cartilage (P = 0.0358).

Conclusions

Multiple candidate genes and GO terms were detected for chondropathies. Our findings may provide a novel insight in the molecular mechanisms of chondropathies.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1978-8) contains supplementary material, which is available to authorized users.

P4HB, a Novel Hypoxia Target Gene Related to Gastric Cancer Invasion and Metastasis

Gastric cancer (GC) is a common tumor-associated lethal disease, and invasiveness and metastasis are primary challenges in its clinical treatment. Hypoxia microenvironment cannot be ignored in the process of metastasis. Hypoxia inducible factor-1α (HIF-1α) is the core component of the hypoxia signaling pathway. The aim of this study was to identify potential hub genes and signaling pathways associated with HIF-1α. We explored the invasiveness- and metastasis-associated phenotype of GC via bioinformatics analysis and molecular studies. Differentially expressed genes (DEGs) were identified in GC cells and HIF-1α-knockdown GC cells. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, and a protein-protein interaction (PPI) network was constructed. Hub genes were identified via centrality analysis and Molecular Complex Detection (MCODE) module analysis. The findings suggested that prolyl 4-hydroxylase beta polypeptide (P4HB) has strong associations with HIF-1α. Further, we observed that HIF-1α and P4HB were upregulated in SGC-7901 and BGC-823 cells. In addition, inhibition of HIF-1α expression reduced invasion and metastasis in GC cells; this effect was partially reversed by P4HB overexpression. Our results confirm that P4HB plays a significant role in the regulatory network of HIF-1α. Therefore, HIF-1α and P4HB may be considered potential biomarkers of GC.

Liraglutide protects high-glucose-stimulated fibroblasts by activating the CD36-JNK-AP1 pathway to downregulate P4HA1

BACKGROUND

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus. It's known that glucagon-like peptide-1 (GLP-1) and prolyl 4-hydroxylase subunit alpha-1 (P4HA1) have significant effect on cardiovascular function, but their interaction in cardiac fibroblasts (CFs) is still being unraveled.

METHODS AND RESULTS

The present study demonstrated that glucose promotes CFs proliferation and cardiac fibrosis. Using qRT-PCR, Western blot, CCK-8, EdU, flow cytometry, wound healing and Transwell assays to explore the functions of liraglutide and P4HA1 in high-glucose (HG)-induced CFs, we proved that liraglutide as well as silencing of P4HA1 inhibited cell proliferation, migration and invasion, and promoted cell cycle arrest and apoptosis in HG-induced CFs. In addition, liraglutide downregulated P4HA1 expression, upregulated CD36 and P-JNK expression levels, and enhanced the DNA binding activity of AP-1 on P4HA1. Inhibition of CD36 or p--JNK promoted P4HA1 expression.

CONCLUSIONS

Liraglutide may down-regulate P4HA1 expression at least partly though CD36-JNK-AP1 pathway, thereby reducing myocardial fibrosis. Therefore, our study provides novel insight into the molecular mechanism and function of liraglutide in HG-mediated CFs.

Mitochondrial NDUFA4L2 protein promotes the vitality of lung cancer cells by repressing oxidative stress

BACKGROUND

Non-small cell lung cancer (NSCLC) accounts for a significant proportion of cancer-related deaths and lacks an effective treatment strategy. NSCLC tissues are generally found in a low oxygen environment. The NDUFA4L2 protein, located in the mitochondria, is encoded by the nucleus genome and is considered a crucial mediator that regulates cell survival. A better understanding of the mechanism of NDUFA4L2 in NSCLC survival in hypoxic environments is essential to design new therapeutic methods.

METHODS

Twenty NSCLC and corresponding paired non-tumorous lung tissue samples were collected. NSCLC cell lines were cultured in hypoxic conditions to investigate the mechanism of NDUFA4L2 in NSCLC. The role of NDUFA4L2 was confirmed by using Western blotting, reactive oxygen species measurement, flow cytometry, immunofluorescence analysis, and wound healing and colony formation assays.

RESULTS

The expression of HIF-1α and mitochondrial NDUFA4L2 increased in NSCLC cell lines cultured in hypoxic conditions (1% O₂ ). NDUFA4L2 was drastically overexpressed in human NSCLC tissues and cell lines cultured in hypoxic conditions. HIF-1α regulated the expression of NDUFA4L2. Knockdown of NDUFA4L2 notably increased mitochondrial reactive oxygen species production, which suppressed the viability of NSCLC.

CONCLUSION

In conclusion, overexpression of NDUFA4L2 is a key factor for maintaining NSCLC growth, suggesting that mitochondrial NDUFA4L2 may be a potential target for the treatment of lung cancer.

Exploration of the chondrosarcoma metabolome; the mTOR pathway as an important pro-survival pathway

Background

Chondrosarcomas are malignant cartilage-producing tumors showing mutations and changes in gene expression in metabolism related genes. In this study, we aimed to explore the metabolome and identify targetable metabolic vulnerabilities in chondrosarcoma.

Methods

A custom-designed metabolic compound screen containing 39 compounds targeting different metabolic pathways was performed in chondrosarcoma cell lines JJ012, SW1353 and CH2879. Based on the anti-proliferative activity, six compounds were selected for validation using real-time metabolic profiling. Two selected compounds (rapamycin and sapanisertib) were further explored for their effect on viability, apoptosis and metabolic dependency, in normoxia and hypoxia. In vivo efficacy of sapanisertib was tested in a chondrosarcoma orthotopic xenograft mouse model.

Results

Inhibitors of glutamine, glutathione, NAD synthesis and mTOR were effective in chondrosarcoma cells. Of the six compounds that were validated on the metabolic level, mTOR inhibitors rapamycin and sapanisertib showed the most consistent decrease in oxidative and glycolytic parameters. Chondrosarcoma cells were sensitive to mTORC1 inhibition using rapamycin. Inhibition of mTORC1 and mTORC2 using sapanisertib resulted in a dose-dependent decrease in viability in all chondrosarcoma cell lines. In addition, induction of apoptosis was observed in CH2879 after 24 h. Treatment of chondrosarcoma xenografts with sapanisertib slowed down tumor growth compared to control mice.

Conclusions

mTOR inhibition leads to a reduction of oxidative and glycolytic metabolism and decreased proliferation in chondrosarcoma cell lines. Although further research is needed, these findings suggest that mTOR inhibition might be a potential therapeutic option for patients with chondrosarcoma.

BAG2 Overexpression Correlates with Growth and Poor Prognosis of Esophageal Squamous Cell Carcinoma

Previous studies have suggested that Bcl2-associated athanogene 2 (BAG2) serves as a crucial regulator for tumorigenesis in multiple tumors. However, little is known about the effect of BAG2 on esophageal squamous cell carcinoma (ESCC). This study focused on investigating whether BAG2 functions as a cancer-promoting gene in ESCC. In this work, gene expression data and clinical information from the NCBI Gene Expression Omnibus (GEO), Oncomine and The Cancer Genome Atlas (TCGA) were collected and analyzed. Expression of BAG2 in ESCC was determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR). BAG2 was knocked down using small interference RNA (si-RNA) approach. Cell proliferation, migration and invasion were assessed by Cell Counting Kit-8 (CCK-8) and transwell assays. Molecular mechanism was detected by western blotting assay. The expression of BAG2 both in ESCC tissues and cells was upregulated and overexpression was associated with worsened prognosis. BAG2 silencing inhibited ESCC cell proliferation, migration and invasion, which was regulated by the phosphatidylinositol-3-kinase (PI3K)/ protein kinase B (AKT) signaling pathway. These results reveal contributions of BAG2 as a predictor and potential therapeutic target in ESCC.

Prognostic value of hypoxia-inducible factor-1 alpha and prolyl 4-hydroxylase beta polypeptide overexpression in gastric cancer

AIM

To investigate the relationship between hypoxia-inducible factor-1α (HIF-1α), prolyl 4-hydroxylase beta (P4HB) expression, and clinicopathologic parameters, as well as the prognostic value of these genes for patients with gastric cancer (GC).

METHODS

Hypoxia is a critical factor that shapes the GC microenvironment. In previous reports, we have demonstrated that P4HB is a potential target of HIF-1α. In the present study, gene expression profiling interactive analysis (GEPIA) was used to analyze the relationship between P4HB and hypoxia-associated genes. To this end, 428 GC tissue samples were used to analyze the expression of HIF-1α and P4HB via immunohistochemical staining. Patient samples were classified as having weak-expression or over-expression both in terms of HIF-1α and P4HB. Correlations between biomarkers and clinicopathological factors were analyzed to predict survival.

RESULTS

P4HB demonstrated a positive correlation with hypoxia-associated genes (P < 0.05). HIF-1α and P4HB overexpression have a significant correlation with TNM staging (χ² = 23.32, P = 0.00; χ² = 65.64, P = 0.00) and peritoneum cavity metastasis (χ² = 12.67, P = 0.00; χ² = 39.29, P = 0.00). In univariate analysis, patients with a high HIF-1α expression trend had a shorter disease-free survival (DFS: 44.80 mo vs 22.06 mo) and overall survival (OS: 49.58 mo vs 39.92 mo). P4HB overexpression reflected similar results: patients with over-expression of P4HB had a shorter survival time than those with weak-expression (DFS: 48.03 mo vs 29.64 mo, OS: 52.48 mo vs 36.87 mo). Furthermore, HIF-1α is also a clinicopathological predictor of dismal prognosis according to multivariate analysis (DFS, 95%CI: 0.52-0.88, P < 0.00; OS, 95%CI: 0.50-0.85, P < 0.00). However, P4HB was meaningful in DFS (95%CI: 0.58-1.00, P < 0.05) but not in OS (95%CI: 0.72-1.23, P > 0.05).

CONCLUSION

Overexpression of HIF-1α and P4HB is associated with poor prognosis in patients with GC. Thus, these genes may be potential prognostic biomarker candidates in GC.

The potential value of CDV3 in the prognosis evaluation in Hepatocellular carcinoma

CDV3 is correlated with tumorigenesis and may affect some biological process in cancer. In this study, we explore the role of CDV3 in HCC. According to the TCGA data base, CDV3 is over-expressed in HCC tissues. Up-regulation of CDV3 is correlated with lower over-all survival rate in HCC patients. In HCC samples from our hospital, CDV3 is also enriched in cancer tissues and CDV3 expression associated with HCC pathological T stage. What is more, higher CDV3 expression could forecast poor survival rate in HCC patients. In conclusion, CDV3 is a biomarker of HCC and could be a potential therapeutic target.