Hypoxia inducible factor 1α-mediated LOX expression correlates with migration and invasion in epithelial ovarian cancer

Glucocorticoid receptor: a harmonizer of cellular plasticity in breast cancer-directs the road towards therapy resistance, metastatic progression and recurrence

Recent therapeutic advances have significantly uplifted the quality of life in breast cancer patients, yet several impediments block the road to disease-free survival. This involves unresponsiveness towards administered therapy, epithelial to mesenchymal transition, and metastatic progression with the eventual appearance of recurrent disease. Attainment of such characteristics is a huge adaptive challenge to which tumour cells respond by acquiring diverse phenotypically plastic states. Several signalling networks and mediators are involved in such a process. Glucocorticoid receptor being a mediator of stress response imparts prognostic significance in the context of breast carcinoma. Involvement of the glucocorticoid receptor in the signalling cascade of breast cancer phenotypic plasticity needs further elucidation. This review attempted to shed light on the inter-regulatory interactions of the glucocorticoid receptor with the mediators of the plasticity program in breast cancer; which may provide a hint for strategizing therapeutics against the glucocorticoid/glucocorticoid receptor axis so as to modulate phenotypic plasticity in breast carcinoma.

Identification of Hypoxia Prognostic Signature in Glioblastoma Multiforme Based on Bulk and Single-Cell RNA-Seq

Glioblastoma (GBM) represents a profoundly aggressive and heterogeneous brain neoplasm linked to a bleak prognosis. Hypoxia, a common feature in GBM, has been linked to tumor progression and therapy resistance. In this study, we aimed to identify hypoxia-related differentially expressed genes (DEGs) and construct a prognostic signature for GBM patients using multi-omics analysis. Patient cohorts were collected from publicly available databases, including the Gene Expression Omnibus (GEO), the Chinese Glioma Genome Atlas (CGGA), and The Cancer Genome Atlas-Glioblastoma Multiforme (TCGA-GBM), to facilitate a comprehensive analysis. Hypoxia-related genes (HRGs) were obtained from the Molecular Signatures Database (MSigDB). Differential expression analysis revealed 41 hypoxia-related DEGs in GBM patients. A consensus clustering approach, utilizing these DEGs' expression patterns, identified four distinct clusters, with cluster 1 showing significantly better overall survival. Machine learning techniques, including univariate Cox regression and LASSO regression, delineated a prognostic signature comprising six genes (ANXA1, CALD1, CP, IGFBP2, IGFBP5, and LOX). Multivariate Cox regression analysis substantiated the prognostic significance of a set of three optimal signature genes (CP, IGFBP2, and LOX). Using the hypoxia-related prognostic signature, patients were classified into high- and low-risk categories. Survival analysis demonstrated that the high-risk group exhibited inferior overall survival rates in comparison to the low-risk group. The prognostic signature showed good predictive performance, as indicated by the area under the curve (AUC) values for one-, three-, and five-year overall survival. Furthermore, functional enrichment analysis of the DEGs identified biological processes and pathways associated with hypoxia, providing insights into the underlying mechanisms of GBM. Delving into the tumor immune microenvironment, our analysis revealed correlations relating the hypoxia-related prognostic signature to the infiltration of immune cells in GBM. Overall, our study highlights the potential of a hypoxia-related prognostic signature as a valuable resource for forecasting the survival outcome of GBM patients. The multi-omics approach integrating bulk sequencing, single-cell analysis, and immune microenvironment assessment enhances our understanding of the intricate biology characterizing GBM, thereby potentially informing the tailored design of therapeutic interventions.

Tumour response to hypoxia: understanding the hypoxic tumour microenvironment to improve treatment outcome in solid tumours

Hypoxia is a common feature of solid tumours affecting their biology and response to therapy. One of the main transcription factors activated by hypoxia is hypoxia-inducible factor (HIF), which regulates the expression of genes involved in various aspects of tumourigenesis including proliferative capacity, angiogenesis, immune evasion, metabolic reprogramming, extracellular matrix (ECM) remodelling, and cell migration. This can negatively impact patient outcomes by inducing therapeutic resistance. The importance of hypoxia is clearly demonstrated by continued research into finding clinically relevant hypoxia biomarkers, and hypoxia-targeting therapies. One of the problems is the lack of clinically applicable methods of hypoxia detection, and lack of standardisation. Additionally, a lot of the methods of detecting hypoxia do not take into consideration the complexity of the hypoxic tumour microenvironment (TME). Therefore, this needs further elucidation as approximately 50% of solid tumours are hypoxic. The ECM is important component of the hypoxic TME, and is developed by both cancer associated fibroblasts (CAFs) and tumour cells. However, it is important to distinguish the different roles to develop both biomarkers and novel compounds. Fibronectin (FN), collagen (COL) and hyaluronic acid (HA) are important components of the ECM that create ECM fibres. These fibres are crosslinked by specific enzymes including lysyl oxidase (LOX) which regulates the stiffness of tumours and induces fibrosis. This is partially regulated by HIFs. The review highlights the importance of understanding the role of matrix stiffness in different solid tumours as current data shows contradictory results on the impact on therapeutic resistance. The review also indicates that further research is needed into identifying different CAF subtypes and their exact roles; with some showing pro-tumorigenic capacity and others having anti-tumorigenic roles. This has made it difficult to fully elucidate the role of CAFs within the TME. However, it is clear that this is an important area of research that requires unravelling as current strategies to target CAFs have resulted in worsened prognosis. The role of immune cells within the tumour microenvironment is also discussed as hypoxia has been associated with modulating immune cells to create an anti-tumorigenic environment. Which has led to the development of immunotherapies including PD-L1. These hypoxia-induced changes can confer resistance to conventional therapies, such as chemotherapy, radiotherapy, and immunotherapy. This review summarizes the current knowledge on the impact of hypoxia on the TME and its implications for therapy resistance. It also discusses the potential of hypoxia biomarkers as prognostic and predictive indictors of treatment response, as well as the challenges and opportunities of targeting hypoxia in clinical trials.

Prognostic value of hypoxia-responsive gene expression profile in patients diagnosed with head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a disease associated with a severe mortality and high risk of distant metastasis and local recurrence. Currently, surgery and radiotherapy are the main treatment modes, however, therapeutic efficacy of radiotherapy is linked to tumor resistance. Hypoxia has been shown to affect outcome of radiotherapy in HNSCC patients. The aim of this study was to verify the expression of the previously identified hypoxia-responsive genes (CA9, CASP14, LOX, GLUT3, SERPINE1, AREG, EREG, CCNB1 and KIF14) in HNSCC patient material as well as assess their prognostic potential. Tumor biopsies obtained before start of radiotherapy from 32 HNSCC patients classified as responders or non-responders were investigated in this study. The mRNA expression was quantified using RT-qPCR. The mRNA expression of CA9, SERPINE1 and KIF14 was significantly higher in the analyzed patient material compared with the non-cancerous oral tissue. Moreover, the KIF14 mRNA expression was significantly higher in the responder group compared to non-responders. Further studies demonstrated that knockdown of KIF14 reverses its radiosensitizing capability. Additionally, low expression of KIF14 mRNA correlated with significantly shorter OS (overall survival). In conclusion, our results suggest that KIF14 might be a useful prognostic and predictive marker in HNSCC.

Increased expression of collagen prolyl hydroxylases in ovarian cancer is associated with cancer growth and metastasis

Tumor hypoxia induces collagen deposition and extensive extracellular matrix remodeling, significantly enhancing the processes of invasion and metastasis. Collagen prolyl-4-hydroxylases (P4HA) play a critical role in collagen post-translational modification. The primary objective of this study is to comprehensively assess the role of P4HA in promoting ovarian cancer growth and facilitating metastasis. Human epithelial ovarian cancer cells were transfected with shRNAs to target P4HA1 and P4HA2. The impact of P4HA knockdown on crucial factors such as collagen I deposition, cell proliferation, and migration were examined in vitro. Additionally, in vivo studies involved the injection of both control and P4HA knockdown cells into athymic mice, enabling the assessment of tumor growth and peritoneal metastasis. The relevance of prolyl hydroxylases to clinical outcomes was then determined by analyzing clinical databases. Quantitative RT-PCR showed upregulation of P4HA1 and P4HA2 mRNA in A2780 cells when exposed to hypoxia. ShRNA-mediated downregulation of P4HA1 and P4HA2 significantly reduced the deposition of collagen I. Knockdown of P4HA expression reduced cell proliferation in vitro and peritoneal seeding in vivo. A2780 cells stably transfected with shP4HA1 and shP4HA2 inhibited tumor growth and metastases in athymic mice. Furthermore, our review of the TCGA dataset revealed that increased P4HA1 and P4HA2 mRNA levels are associated with decreased overall survival in patients with ovarian cancer. The increased expression of collagen P4HA has been linked to ovarian cancer growth and metastasis. This evidence highlights their potential as prognostic biomarkers and promising therapeutic targets.

Role of the Hypoxic-Secretome in Seed and Soil Metastatic Preparation

During tumor growth, the delivery of oxygen to cells is impaired due to aberrant or absent vasculature. This causes an adaptative response that activates the expression of genes that control several essential processes, such as glycolysis, neovascularization, immune suppression, and the cancer stemness phenotype, leading to increased metastasis and resistance to therapy. Hypoxic tumor cells also respond to an altered hypoxic microenvironment by secreting vesicles, factors, cytokines and nucleic acids that modify not only the immediate microenvironment but also organs at distant sites, allowing or facilitating the attachment and growth of tumor cells and contributing to metastasis. Hypoxia induces the release of molecules of different biochemical natures, either secreted or inside extracellular vesicles, and both tumor cells and stromal cells are involved in this process. The mechanisms by which these signals that can modify the premetastatic niche are sent from the primary tumor site include changes in the extracellular matrix, recruitment and activation of different stromal cells and immune or nonimmune cells, metabolic reprogramming, and molecular signaling network rewiring. In this review, we will discuss how hypoxia might alter the premetastatic niche through different signaling molecules.

Clinicopathological and prognostic value of lysyl oxidase expression in gastric cancer: a systematic review, meta-analysis and bioinformatic analysis

The association between the expression of Lysyl oxidase (LOX) and its clinicopathological parameters and prognosis in patients with gastric cancer (GC) is still disputed. We performed this meta-analysis and bioinformatics analysis to clarify the relationship between the expression and methylation level of LOX with its clinicopathological parameters and prognostic value. We applied odds ratios with a 95% confidence interval to study the associations between LOX expression and clinicopathological parameters and overall survival (OS) in GC patients. In addition, association analysis of promoter methylation levels and expression of LOX with its prognostic value was performed using the Cancer Genome Atlas (TCGA) and four Gene Expression Omnibus (GEO) datasets. The PRISMA 2020 checklist was used to guide the data extraction and analysis. This meta-analysis includes seven clinical studies with a total of 1435 GC patients. LOX expression was related to lymph node metastasis and tumor distant metastasis in GC patients, but not to gender, tumor differentiation, Lauren classification, or tumor depth of invasion. Patients with GC grouped in high-expression of LOX had a much worse OS than those in low-expression. In addition, TCGA and four GEO datasets with 1279 samples were included in the bioinformatics analysis. The bioinformatics analysis showed that patients with high LOX levels had poor OS; low levels of methylation at some cg sites in the LOX gene were strongly related to poor OS and PFS; and methylation levels of LOX are negatively correlated with advanced tumor stage. The conclusion from comprehensive DNA methylation and gene expression analysis supports LOX as a specific diagnostic and prognosis biomarker in GC. LOX expression was related to lymph node metastasis, tumor distant metastasis and poor prognosis in GC. Low methylation levels were related to advanced tumor stage and poor prognosis in GC. Integrative analysis supports LOX as a specific diagnostic and prognosis biomarker in GC.

The hypoxia-related signature predicts prognosis, pyroptosis and drug sensitivity of osteosarcoma

Osteosarcoma (OS) is one of the most common types of solid sarcoma with a poor prognosis. Solid tumors are often exposed to hypoxic conditions, while hypoxia is regarded as a driving force in tumor recurrence, metastasis, progression, low chemosensitivity and poor prognosis. Pytoptosis is a gasdermin-mediated inflammatory cell death that plays an essential role in host defense against tumorigenesis. However, few studies have reported relationships among hypoxia, pyroptosis, tumor immune microenvironment, chemosensitivity, and prognosis in OS. In this study, gene and clinical data from Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus (GEO) databases were merged to develop a hypoxia risk model comprising four genes (PDK1, LOX, DCN, and HMOX1). The high hypoxia risk group had a poor prognosis and immunosuppressive status. Meanwhile, the infiltration of CD8⁺ T cells, activated memory CD4⁺ T cells, and related chemokines and genes were associated with clinical survival outcomes or chemosensitivity, the possible crucial driving forces of the OS hypoxia immune microenvironment that affect the development of pyroptosis. We established a pyroptosis risk model based on 14 pyroptosis-related genes to independently predict not only the prognosis but also the chemotherapy sensitivities. By exploring the various connections between the hypoxic immune microenvironment and pyroptosis, this study indicates that hypoxia could influence tumor immune microenvironment (TIM) remodeling and promote pyroptosis leading to poor prognosis and low chemosensitivity.

Self-Sustained Regulation or Self-Perpetuating Dysregulation: ROS-dependent HIF-YAP-Notch Signaling as a Double-Edged Sword on Stem Cell Physiology and Tumorigenesis

Organ development, homeostasis, and repair often rely on bidirectional, self-organized cell-niche interactions, through which cells select cell fate, such as stem cell self-renewal and differentiation. The niche contains multiplexed chemical and mechanical factors. How cells interpret niche structural information such as the 3D topology of organs and integrate with multiplexed mechano-chemical signals is an open and active research field. Among all the niche factors, reactive oxygen species (ROS) have recently gained growing interest. Once considered harmful, ROS are now recognized as an important niche factor in the regulation of tissue mechanics and topology through, for example, the HIF-YAP-Notch signaling pathways. These pathways are not only involved in the regulation of stem cell physiology but also associated with inflammation, neurological disorder, aging, tumorigenesis, and the regulation of the immune checkpoint molecule PD-L1. Positive feedback circuits have been identified in the interplay of ROS and HIF-YAP-Notch signaling, leading to the possibility that under aberrant conditions, self-organized, ROS-dependent physiological regulations can be switched to self-perpetuating dysregulation, making ROS a double-edged sword at the interface of stem cell physiology and tumorigenesis. In this review, we discuss the recent findings on how ROS and tissue mechanics affect YAP-HIF-Notch-PD-L1 signaling, hoping that the knowledge can be used to design strategies for stem cell-based and ROS-targeting therapy and tissue engineering.

HIF-1α Is a Rational Target for Future Ovarian Cancer Therapies

Ovarian cancer is the eighth most commonly diagnosed cancer among women worldwide. Even with the development of novel drugs, nearly one-half of the patients with ovarian cancer die within five years of diagnosis. These situations indicate the need for novel therapeutic agents for ovarian cancer. Increasing evidence has shown that hypoxia-inducible factor-1α(HIF-1α) plays an important role in promoting malignant cell chemoresistance, tumour metastasis, angiogenesis, immunosuppression and intercellular interactions. The unique microenvironment, crosstalk and/or interaction between cells and other characteristics of ovarian cancer can influence therapeutic efficiency or promote the disease progression. Inhibition of the expression or activity of HIF-1α can directly or indirectly enhance the therapeutic responsiveness of tumour cells. Therefore, it is reasonable to consider HIF-1α as a potential therapeutic target for ovarian cancer. In this paper, we summarize the latest research on the role of HIF-1α and molecules which can inhibit HIF-1α expression directly or indirectly in ovarian cancer, and drug clinical trials about the HIF-1α inhibitors in ovarian cancer or other solid malignant tumours.

Serum Lysyl Oxidase Levels and Lysyl Oxidase Gene Polymorphism in Ovarian Cancer Patients of Eastern Indian Population

(1) Background: Lysyl oxidase (LOX) plays a dual role in carcinogenesis and studies show a higher risk of cancer in LOX G473A variants. The present study evaluated the pattern of LOX G473A polymorphism (rs1800449) and serum LOX levels in ovarian cancer patients. (2) Methods: Serum LOX levels were estimated by enzyme linked immunosorbent assay (ELISA). A polymorphism of rs1800449 of LOX gene was detected by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Selected samples were sequenced for external validation. (3) Results: A majority of study participants were from low socio-economic status. Serum LOX level was significantly higher in ovarian cancer patients as compared to control. Serum LOX level in early-stage ovarian cancer was significantly lower as compared to advanced stage (FIGO stage III & IV). Wild type GG genotype was used as reference. Genotypes AA were associated with a significant risk of epithelial ovarian cancer (OR 3.208; p value- 0.033). A allele of rs1800449 polymorphism of LOX gene, the odds ratio was 1.866 (95% Confidence Interval 1.112–3.16) p value = 0.017 (4) Conclusions: A allele of rs1800449 polymorphism of LOX gene presents an increased risk of ovarian cancer in East Indian population. Serum LOX levels could be a potential biomarker for the diagnosis and prognosis of ovarian cancer.

Lysyl Oxidase Mechanisms to Mediate Gastrointestinal Cancer Progression

Background

Malignancy is a complex process resulting from different changes such as extracellular matrix (ECM) remodeling and stiffness. One of the important enzymes that contribute to ECM remodeling is lysyl oxidase (Lox) that is overexpressed in different types of human cancers. Because of the high prevalence and poor survival of gastrointestinal (GI) malignancies in this review, we discuss the association between Lox activity and the progression of GI cancers. Lox proteins are a group of extracellular enzymes that catalyzed the cross-linking of collagen and elastin, so they have important roles in the control of structure and homeostasis of ECM. Abnormal activation and expression of the Lox family of proteins lead to changes in the ECM toward increased rigidity and fibrosis. Stiffness of ECM can contribute to the pathogenesis of cancers.

Summary

Dysregulation of Lox expression is a factor in both fibrotic diseases and cancer. ECM stiffness by Lox overactivity creates a physical barrier against intratumoral concentration of chemotherapeutic drugs and facilitates cancer inflammation, angiogenesis, and metastasis.

Key Message

Because of the roles of Lox in GI cancers, development targeting Lox protein isotypes may be an appropriate strategy for treatment of GI cancers and improvement in survival of patients.

Understanding the molecular mechanism associated with reversal of oral submucous fibrosis targeting hydroxylysine aldehyde-derived collagen cross-links

Fibrosis is a pathological state characterized by excessive deposition of the extracellular matrix components leading to impaired tissue function in the affected organ. It results in scarring of the affected tissue akin to an over-healing wound as a consequence of chronic inflammation and repair in response to injury. Persistent trauma of susceptible oral mucosa due to habitual chewing of betel quid resulting in zealous healing of the mucosal tissue is one plausible explanation for the onset of oral submucous fibrosis (OSF). The irreversibility and resistance of collagen to degradation and its high potential to undergo malignant change are a major reason for morbidity in OSF. Hence, early diagnosis and timely treatment are crucial to prevent the progression of OSF to malignancy. This review focuses on the mechanistic insight into the role of collagen cross-links in advancing fibrosis and possible therapeutic targets that bring about a reversal of fibrosis. These options may be beneficial if attempted as a specific therapeutic modality in OSF as is in organ fibrosis. The upregulation of lysyl oxidase and lysyl hydroxylase has been shown to exhibit the higher levels of the hydroxylysine aldehyde-derived cross-links in fibrosis and tumor stroma promoting the tumor cell survival, resistance, and invasion. The in silico analysis highlights the potential drugs that may target the genes regulating collagen crosslinking.

Anti-Cancer Activity of Phytochemicals Targeting Hypoxia-Inducible Factor-1 Alpha

Hypoxia-inducible factor-1 alpha (HIF-1α) is overexpressed in cancer, leading to a poor prognosis in patients. Diverse cellular factors are able to regulate HIF-1α expression in hypoxia and even in non-hypoxic conditions, affecting its progression and malignant characteristics by regulating the expression of the HIF-1α target genes that are involved in cell survival, angiogenesis, metabolism, therapeutic resistance, et cetera. Numerous studies have exhibited the anti-cancer effect of HIF-1α inhibition itself and the augmentation of anti-cancer treatment efficacy by interfering with HIF-1α-mediated signaling. The anti-cancer effect of plant-derived phytochemicals has been evaluated, and they have been found to possess significant therapeutic potentials against numerous cancer types. A better understanding of phytochemicals is indispensable for establishing advanced strategies for cancer therapy. This article reviews the anti-cancer effect of phytochemicals in connection with HIF-1α regulation.

Meta-Analysis-Assisted Detection of Gravity-Sensitive Genes in Human Vascular Endothelial Cells

Gravity affects the function and maintenance of organs, such as bones, muscles, and the heart. Several studies have used DNA microarrays to identify genes with altered expressions in response to gravity. However, it is technically challenging to combine the results from various microarray datasets because of their different data structures. We hypothesized that it is possible to identify common changes in gene expression from the DNA microarray datasets obtained under various conditions and methods. In this study, we grouped homologous genes to perform a meta-analysis of multiple vascular endothelial cell and skeletal muscle datasets. According to the t-distributed stochastic neighbor embedding (t-SNE) analysis, the changes in the gene expression pattern in vascular endothelial cells formed specific clusters. We also identified candidate genes in endothelial cells that responded to gravity. Further, we exposed human umbilical vein endothelial cells (HUVEC) to simulated microgravity (SMG) using a clinostat and measured the expression levels of the candidate genes. Gene expression analysis using qRT-PCR revealed that the expression level of the prostaglandin (PG) transporter gene SLCO2A1 decreased in response to microgravity, consistent with the meta-analysis of microarray datasets. Furthermore, the direction of gravity affected the expression level of SLCO2A1, buttressing the finding that its expression was affected by gravity. These results suggest that a meta-analysis of DNA microarray datasets may help identify new target genes previously overlooked in individual microarray analyses.

Histone deacetylase inhibitor induced pVHL-independent degradation of HIF-1α and hierarchical quality control of pVHL via chaperone system

The mortality rate of ovarian cancer is increasing and the role of hypoxia inducible factor-1α (HIF-1α) in tumor progression has been confirmed. von Hippel-Lindau tumor suppressor protein (pVHL) binds HIF-1α and mediates proteasome degradation of HIF-1α. Besides, histone deacetylase inhibitor (HDACi) mitigates tumor growth via targeting HIF-1α, whereas underlying mechanism still requires investigation. In this research, we exposed ovarian cancer cell lines OV-90 and SKOV-3 to escalating concentrations of HDACi LBH589. As a result, cell viability was significantly suppressed and expression of HIF-1α was remarkably reduced along with decreased levels of signal molecules, including phosphoinositide 3-kinase (PI3K) and glycogen synthase kinase 3β (GSK3β) (P = 0.000). Interestingly, pVHL was expressed in a notably declining tendency (P = 0.000). Chaperone heat shock protein-70 (HSP70) was expressed in an ascending manner, whereas expression of chaperonin TCP-1α was reduced clearly (P = 0.000). Besides, co-inhibition of pVHL plus HDAC did not contribute to a remarkable difference in HIF-1α expression as compared with single HDAC inhibition. Furthermore, both cell lines were transfected with plasmids of VHL plus VHL binding protein-1 (VBP-1). Consequently, the expression of HIF-1α as well as lactate dehydrogenase-A (LDHA) was remarkably decreased (P = 0.000). These findings indicate HDACi may repress expression of HIF-1α via inhibiting PI3K and GSK3β and promote degradation of HIF-1α via HSP70, independent of pVHL. Additionally, a sophisticated network of HDAC and chaperones may involve in pVHL quality control.

SIO: A Spatioimageomics Pipeline to Identify Prognostic Biomarkers Associated with the Ovarian Tumor Microenvironment

Stromal and immune cells in the tumor microenvironment (TME) have been shown to directly affect high-grade serous ovarian cancer (HGSC) malignant phenotypes, however, how these cells interact to influence HGSC patients' survival remains largely unknown. To investigate the cell-cell communication in such a complex TME, we developed a SpatioImageOmics (SIO) pipeline that combines imaging mass cytometry (IMC), location-specific transcriptomics, and deep learning to identify the distribution of various stromal, tumor and immune cells as well as their spatial relationship in TME. The SIO pipeline automatically and accurately segments cells and extracts salient cellular features to identify biomarkers, and multiple nearest-neighbor interactions among tumor, immune, and stromal cells that coordinate to influence overall survival rates in HGSC patients. In addition, SIO integrates IMC data with microdissected tumor and stromal transcriptomes from the same patients to identify novel signaling networks, which would lead to the discovery of novel survival rate-modulating mechanisms in HGSC patients.

An Oxygen-Concentration-Controllable Multiorgan Microfluidic Platform for Studying Hypoxia-Induced Lung Cancer-Liver Metastasis and Screening Drugs

Various cancer metastasis models based on organ-on-a-chip platforms have been established to study molecular mechanisms and screen drugs. However, current platforms can neither reveal hypoxia-induced cancer metastasis mechanisms nor allow drug screening under a hypoxia environment on a multiorgan level. We have developed a three-dimensional-culture multiorgan microfluidic (3D-CMOM) platform in which the dissolved oxygen concentration can be precisely controlled. An organ-level lung cancer and liver linkage model was established under normoxic/hypoxic conditions. A transcriptomics analysis of the hypoxia-induced lung cancer cells (A549 cells) on the platform indicated that the hypoxia-inducible factor 1α (HIF-1α) pathway could elevate epithelial-mesenchymal transition (EMT) transcription factors (Snail 1 and Snail 2), which could promote cancer metastasis. Then, protein detection demonstrated that HIF-1α and EMT transcription factor expression levels were positively correlated with the secretion of cancer metastasis damage factors alpha-fetoprotein (AFP), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (γ-GT) from liver cells. Furthermore, the cancer treatment effects of HIF-1α inhibitors (tirapazamine, SYP-5, and IDF-11774) were evaluated using the platform. The treatment effect of SYP-5 was enhanced under the hypoxic conditions with fewer side effects, similar to the findings of TPZ. We can envision its wide application in future investigations of cancer metastasis and screening of drugs under hypoxic conditions with the potential to replace animal experiments.

Integrated miRNA-mRNA Analysis Reveals Potential Biomarkers of Chemoresistance in Ovarian Cancer

The current study aimed to determine potential biomarkers related to chemoresistance in ovarian cancer and the involved signaling pathways through bioinformatics analysis. This was followed by an exploration of the related indices on the occurrence and development of chemoresistance in ovarian cancer (OC). Five miRNA/mRNA expression datasets on chemoresistance OC were obtained from the Geodatabase. The significantly different expressed miRNAs (DEMs) and differently expressed genes (DEGs) between chemoresistant OC tissues and control tissues were screened using the GEO2R online tool. Afterwards, pathway analysis was utilized to analyze the DEGs and Cytoscape with STRING 11.0 was used to visualize the protein-protein interaction (PPI) network of DEGs. Afterwards, TFmiR webserver was performed to predict the TF-miRNA-mRNA network. Finally, KM-Plotter was utilized to determine the effects of hub genes and key miRNAs on survival time. A total of 24 DEMs and 548 DEGs were screened from four different datasets on chemoresistance in OC. Seven mRNA-miRNA pairs were found. Survival analysis based on the Kaplan-Meier plotter revealed that 11 biomarkers, including hsa-miR-363, hsa-miR-125b, CDKN1N, JUN, KFL4, IGFBP3, TGFBR2, CCR5, SPP1, LOX, and MMP1, which were associated with TF-miRNA-mRNA network, were closely associated with overall survival (OS) in patients with OC (P< 0.05). The integrated genomic analysis method was successful in screening novel and important genes for the occurrence and progression of chemoresistance in OC. Moreover, this method provided valuable information for investigating chemoresistance in OC and also forms the basis for further functional research.

Regulation of lysyl oxidase expression in THP-1 cell-derived M2-like macrophages

Lysyl oxidase (LOX) is a copper-containing enzyme and its overexpression in tumor tissues promote tumor metastasis through the crosslinking of extracellular matrix. Our previous report demonstrated that LOX expression is significantly increased in human leukemic THP-1 cell-derived M2-like macrophages, and histone modification plays a key role in its induction. However, the rigorous mechanism of LOX regulation remains unclear. In this study, we investigated the role of functional transcription factors, hypoxia-inducible factor 1α (HIF1α), signal transducer and activator of transcription 3 (STAT3) and forkhead box O1 (FOXO1) in LOX regulation in M2-like macrophages. HIF1α expression was significantly increased in M2-like macrophages, and HIF1α inhibitor, TX402, suppressed LOX induction. The significant STAT3 activation was also observed in M2-like macrophages. Additionally, LOX induction was canceled in the presence of STAT3 inhibitor, S3I-201, suggesting that HIF1α and STAT3 pathways play a critical role in LOX induction. On the other hand, our ChIP results clearly indicated that the enrichment of FOXO1 within the lox promoter region was dramatically decreased in M2-like macrophages. In this context, knockdown of FOXO1 further enhanced LOX induction. LOX induction and HIF1α binding to the lox promoter region were suppressed in FOXO1-overexpressed cells, suggesting that the FOXO1 binding to the lox promoter region counteracted HIF1α binding to that region. Overall, the present data suggested that both of HIF1α and STAT3 were required for LOX induction in M2-like macrophages, and loss of FOXO1 within the lox promoter region facilitated HIF1α binding to that region which promoted LOX induction.

Overexpression of STAT4 under hypoxia promotes EMT through miR-200a/STAT4 signal pathway

AIMS

Previous reports have found that STAT4 is involved in the epithelial-mesenchymal transition (EMT), thereby regulating the metastasis and invasion of ovarian cancer. However, the mechanisms underlying remain unclear.

MAIN METHODS

We first established hypoxia-induced in vivo and in vitro models. The expression levels of signal transducer and activator of transcription 4 (STAT4), the markers of EMT and microRNA-200a (miR-200a) were assessed by western blot and qRT-PCR analysis, respectively. Through the bioinformatics analysis and luciferase assay, the relationship between miR-200a and SATA4 was performed. The gain- and loss-function experiments were performed to examine the role of miR-200a/STAT4 axis.

KEY FINDINGS

The results showed that the protein level of STAT4 was significantly up-regulated in our hypoxia-exposed models, and contributed to the regulating of EMT. Besides, we found STAT4 was a direct target of miR-200a. Overexpression of miR-200a repressed the expression of STAT4, and inhibited EMT progress, whereas the silencing of miR-200a promoted the STAT4-mediated EMT regulation both in vitro and in vivo.

SIGNIFICANCE

Our results provided a potential molecular mechanism by which miR-200a involved in hypoxia-induced metastasis and invasion in ovarian cancer, suggesting a possible target for the treatment of ovarian cancer.

Simultaneously targeting cancer-associated fibroblasts and angiogenic vessel as a treatment for TNBC

Fibrotic tumor stroma plays an important role in facilitating triple-negative breast cancer (TNBC) progression and chemotherapeutic resistance. We previously reported a rationally designed protein (ProAgio) that targets integrin αvβ3 at a novel site. ProAgio induces apoptosis via the integrin. Cancer-associated fibroblasts (CAFs) and angiogenic endothelial cells (aECs) in TNBC tumor express high levels of integrin αvβ3. ProAgio effectively induces apoptosis in CAFs and aECs. The depletion of CAFs by ProAgio reduces intratumoral collagen and decreases growth factors released from CAFs in the tumor, resulting in decreased cancer cell proliferation and apoptotic resistance. ProAgio also eliminates leaky tumor angiogenic vessels, which consequently reduces tumor hypoxia and improves drug delivery. The depletion of CAFs and reduction in hypoxia by ProAgio decreases lysyl oxidase (LOX) secretion, which may play a role in the reduction of metastasis. ProAgio stand-alone or in combination with a chemotherapeutic agent provides survival benefit in TNBC murine models, highlighting the therapeutic potential of ProAgio as a treatment strategy.

Targeting Lysyl Oxidase Family Meditated Matrix Cross-Linking as an Anti-Stromal Therapy in Solid Tumours

Simple Summary

To improve efficacy of solid cancer treatment, efforts have shifted towards targeting both the cancer cells and the surrounding tumour tissue they grow in. The lysyl oxidase (LOX) family of enzymes underpin the fibrotic remodeling of the tumour microenvironment to promote both cancer growth, spread throughout the body and modulate response to therapies. This review examines how the lysyl oxidase family is involved in tumour development, how they can be targeted, and their potential as diagnostic and prognostic biomarkers in solid tumours.

Abstract

The lysyl oxidase (LOX) family of enzymes are a major driver in the biogenesis of desmoplastic matrix at the primary tumour and secondary metastatic sites. With the increasing interest in and development of anti-stromal therapies aimed at improving clinical outcomes of cancer patients, the Lox family has emerged as a potentially powerful clinical target. This review examines how lysyl oxidase family dysregulation in solid cancers contributes to disease progression and poor patient outcomes, as well as an evaluation of the preclinical landscape of LOX family targeting therapeutics. We also discuss the suitability of the LOX family as a diagnostic and/or prognostic marker in solid tumours.

The Significance of MicroRNAs Expression in Regulation of Extracellular Matrix and Other Drug Resistant Genes in Drug Resistant Ovarian Cancer Cell Lines

Ovarian cancer rates the highest mortality among all gynecological malignancies. The main reason for high mortality is the development of drug resistance. It can be related to increased expression of drug transporters and increased expression of extracellular matrix (ECM) proteins. Our foremost aim was to exhibit alterations in the miRNA expression levels in cisplatin (CIS), paclitaxel (PAC), doxorubicin (DOX), and topotecan (TOP)-resistant variants of the W1 sensitive ovarian cancer cell line-using miRNA microarray. The second goal was to identify miRNAs responsible for the regulation of drug-resistant genes. According to our observation, alterations in the expression of 40 miRNAs were present. We could observe that, in at least one drug-resistant cell line, the expression of 21 miRNAs was upregulated and that of 19 miRNAs was downregulated. We identified target genes for 22 miRNAs. Target analysis showed that miRNA regulates key genes responsible for drug resistance. Among others, we observed regulation of the ATP-binding cassette subfamily B member 1 gene (ABCB1) in the paclitaxel-resistant cell line by miR-363 and regulation of the collagen type III alpha 1 chain gene (COL3A1) in the topotekan-resistant cell line by miR-29a.

Hypoxia Stimulates Synthesis of Neutrophil Gelatinase-Associated Lipocalin in Aortic Valve Disease

Objective: Aortic valve disease is commonly found in the elderly population. It is characterized by dysregulated extracellular matrix remodeling followed by extensive microcalcification of the aortic valve and activation of valve interstitial cells. The mechanism behind these events are largely unknown. Studies have reported expression of hypoxia inducible factor-1 alpha (HIF1α) in calcific nodules in aortic valve disease, therefore we investigated the effect of hypoxia on extracellular matrix remodeling in aged aortic valves. Approach and Results: Western blotting revealed elevated expression of HIF1α and the complex of matrix metalloprotease 9 (MMP9) and neutrophil gelatinase-associated lipocalin (NGAL) in aged porcine aortic valves cultured under hypoxic conditions. Consistently, immunofluorescence staining showed co-expression of MMP9 and NGAL in the fibrosa layer of these porcine hypoxic aortic valves. Gelatinase zymography demonstrated that the activity of MMP9-NGAL complex was significantly increased in aortic valves in 13% O2 compared to 20% O2. Importantly, the presence of ectopic elastic fibers in the fibrosa of hypoxic aortic valves, also detected in human diseased aortic valves, suggests altered elastin homeostasis due to hypoxia. Conclusion: This study demonstrates that hypoxia stimulates pathological extracellular matrix remodeling via expression of NGAL and MMP9 by valve interstitial cells.

Mutual Expression of ALDH1A1, LOX, and Collagens in Ovarian Cancer Cell Lines as Combined CSCs- and ECM-Related Models of Drug Resistance Development

A major contributor leading to treatment failure of ovarian cancer patients is the drug resistance of cancer cell. CSCs- (cancer stem cells) and ECM (extracellular matrix)-related models of drug resistance are described as independently occurring in cancer cells. Lysyl oxidase (LOX) is another extracellular protein involved in collagen cross-linking and remodeling of extracellular matrix and has been correlated with tumor progression. The expression of LOX, COL1A2, COL3A1, and ALDH1A1 was performed in sensitive (A2780, W1) and resistant to paclitaxel (PAC) (A2780PR1 and W1PR2) and topotecan (TOP) (W1TR) cell lines at the mRNA (real-time PCR analysis) and protein level (Western blot and immunofluorescence analysis). The ALDH1A1 activity was measured with the ALDEFLUOR test and flow cytometry analysis. The protein expression in ovarian cancer tissues was determined by immunohistochemistry. We observed an increased expression of LOX and collagens in PAC and TOP resistant cell lines. Subpopulations of ALDH1A1 positive and negative cells were also noted for examined cell lines. Additionally, the coexpression of LOX with ALDH1A1 and COL1A2 with ALDH1A1 was observed. The expression of LOX, collagens, and ALDH1A1 was also detected in ovarian cancer lesions. In our study LOX, ALDH1A1 and collagens were found to be coordinately expressed by cells resistant to PAC (LOX, ALDH1A1, and COL1A2) or to TOP (LOX and ALDH1A1). This represents the study where molecules related with CSCs (ALDH1A1) and ECM (LOX, collagens) models of drug resistance are described as occurring simultaneously in ovarian cancer cells treated with PAC and TOP.

The fibrotic tumor stroma

Intratumoral fibrosis results from the deposition of a cross-linked collagen matrix by cancer-associated fibroblasts (CAFs). This type of fibrosis has been shown to exert mechanical forces and create a biochemical milieu that, together, shape intratumoral immunity and influence tumor cell metastatic behavior. In this Review, we present recent evidence that CAFs and tumor cells are regulated by provisional matrix molecules, that metastasis results from a change in the type of stromal collagen cross-link, and that fibrosis and inflammation perpetuate each other through proteolytic and chemotactic mediators released into the tumor stroma. We also discuss aspects of the emerging biology that have potential therapeutic value.

Separation of two sub-groups with different DNA content after treatment of T-47D breast cancer cells with low dose-rate irradiation and intermittent hypoxia

Background Previous studies have shown that combined treatment with internal ultra-low dose-rate irradiation selectively inactivated hypoxic T-47D breast cancer cells after three to five weeks of treatment. However, 2-3% of the hypoxic cells were found to survive and restart proliferation upon re-oxygenation. Purpose To investigate the metastatic potential and characteristics of radiosensitivity of these surviving cells, named T - 47 D_S. Material and Methods The T - 47 D_S cells were grown in ambient air without irradiation. A cloning experiment identified two sub-groups with different DNA content ([Formula: see text] and [Formula: see text]). Furthermore, radiosensitivity and presence of hyper-radiosensitivity (HRS) was measured by Co-60 challenge irradiation and relative migration was determined by scratch assays. Results The two subpopulations of T - 47 D_S had different DNA content; one had abnormally high DNA content ([Formula: see text]) and one had DNA content similar to wild-type T-47D cells ([Formula: see text]). HRS was surprisingly present in cells of the cloned population [Formula: see text], but was absent in cells of both [Formula: see text] and T - 47 D_S. The radio response of T - 47 D_S, [Formula: see text] at higher radiation doses were similar to that of T-47D cells, and neither subpopulation showed increased migration compared with wild-type T-47D. Conclusion No increase in the risk of metastasis was found and only slight changes in radiosensitivity in response to conventional clinical doses was observed. Thus, the data suggest that if ultra-low dose-rate irradiation is used for targeting the hypoxic tumor fraction, conventional high dose-rate irradiation can be used to eradicate eventual surviving cells as well as cells in the well oxygenated areas of the tumor.

Hypoxia-inducible factor-1α regulates epithelial-to-mesenchymal transition in paraquat-induced pulmonary fibrosis by activating lysyl oxidase

Pulmonary fibrosis (PF) is one of the most prevalent causes of death following paraquat (PQ) poisoning. As demonstrated in previous studies by the present authors, epithelial-to-mesenchymal transition (EMT) is associated with PQ-induced PF. In addition, hypoxia-inducible factor-1α (HIF-1α) and lysyl oxidase (LOX) promote EMT following PQ poisoning. However, the association between HIF-1α- and LOX-mediated regulation of EMT remains unclear. The present study investigated the association between HIF-1α and LOX with regard to PQ-induced EMT. A549 and RLE-6TN cells were treated with PQ, and HIF-1α and LOX expression was silenced with short interfering RNAs. Changes in the expression of HIF-1α, LOX, β-catenin and EMT-related makers were detected using real-time quantitative polymerase chain reaction, immunofluorescence, and western blotting. HIF-1α and LOX were associated with PQ-induced EMT, and their expression levels were significantly increased (P<0.05). LOX expression was significantly decreased following PQ poisoning when HIF-1α expression was inhibited (P<0.05). However, the level of HIF-1α did not change significantly when LOX was silenced. The expression level of β-catenin and the degree of EMT were significantly decreased following HIF-1α and LOX silencing in both cell lines (P<0.05). The association between HIF-1α and LOX in regulating EMT during PQ-induced PF may be unidirectional. HIF-1α may regulate PQ-induced EMT through the LOX/β-catenin pathway.

Herbal compound Teng-Long-Bu-Zhong-Tang inhibits metastasis in human RKO colon carcinoma

Metastasis is one of the primary obstacles to the successful treatment of colorectal cancer. Teng-Long-Bu-Zhong-Tang (TLBZT) is a modern Chinese herbal formula that may be useful in the treatment of metastatic colorectal cancer. The present study evaluated the effects of TLBZT on lung metastasis in human RKO colon carcinoma cells injected into mice via the tail vein. The results demonstrated that TLBZT inhibited the metastasis of human RKO colon carcinoma cells to the lungs. TLBZT downregulated the expression of LOX and hypoxia-inducible factor 1α. TLBZT also inhibited the expression of integrins αV and β3 and the phosphorylation of focal adhesion kinase. These results indicate that TLBZT inhibits the lung metastasis of RKO colon carcinoma by regulating the expression of multiple genes. The results of the present study provide a new basis for the management of colorectal cancer metastasis using treatments derived from Chinese herbs.

Epithelial-to-Mesenchymal Transition in the Female Reproductive Tract: From Normal Functioning to Disease Pathology

Epithelial-to-mesenchymal transition (EMT) is a physiological process that is vital throughout the human lifespan. In addition to contributing to the development of various tissues within the growing embryo, EMT is also responsible for wound healing and tissue regeneration later in adulthood. In this review, we highlight the importance of EMT in the development and normal functioning of the female reproductive organs (the ovaries and the uterus) and describe how dysregulation of EMT can lead to pathological conditions, such as endometriosis, adenomyosis, and carcinogenesis. We also summarize the current literature relating to EMT in the context of ovarian and endometrial carcinomas, with a particular focus on how molecular mechanisms and the tumor microenvironment can govern cancer cell plasticity, therapy resistance, and metastasis.

Human SLFN5 is a transcriptional co-repressor of STAT1-mediated interferon responses and promotes the malignant phenotype in glioblastoma

We provide evidence that the IFN-regulated member of the Schlafen (SLFN) family of proteins, SLFN5, promotes the malignant phenotype in glioblastoma multiforme (GBM). Our studies indicate that SLFN5 expression promotes motility and invasiveness of GBM cells, and that high levels of SLFN5 expression correlate with high grade gliomas and shorter overall survival in patients suffering from GBM. In efforts to uncover the mechanism by which SLFN5 promotes GBM tumorigenesis, we found that this protein is a transcriptional co-repressor of STAT1. Type-I IFN treatment triggers the interaction of STAT1 with SLFN5, and the resulting complex negatively controls STAT1-mediated gene transcription via interferon stimulated response elements (ISRE). Thus, SLFN5 is both an IFN-stimulated response gene and a repressor of IFN-gene transcription, suggesting the existence of a negative-feedback regulatory loop that may account for suppression of antitumor immune responses in glioblastoma.

Uncovering the role of nuclear Lysyl oxidase (LOX) in advanced high grade serous ovarian cancer

OBJECTIVE

Lysyl oxidase (LOX) is an enzyme that catalyzes the cross-linking of collagen and elastin in the extracellular matrix, thus controlling the tensile strength of tissues. Along with this primary function, there are evidences supporting a role for LOX in many critical biological functions, including gene expression regulation, cell growth, adhesion and migration. Accordingly, recent studies have supported a pivotal role for LOX in cancer progression and metastasis. The current study aimed at investigating the prognostic significance and the functional role of intracellular LOX in ovarian cancer.

METHODS

To this end, we analyzed LOX expression by immunohistochemistry in archived tumor material from advanced high grade serous ovarian cancer (HGSOC) patients (n=70) and correlated data with clinicopathological parameters and with response to chemotherapy. In vitro experiments were also used to investigate the functional consequences of LOX expression on behavioral aspects of HGSOC cells.

RESULTS

Our results showed that nuclear LOX expression is associated with unfavorable outcome in advanced HGSOC, being an independent prognostic factor for disease recurrence. Besides, high nuclear levels were seen to be associated with resistance to first-line chemotherapy. Through gene expression modulation experiments in HGSOC cell lines, we demonstrate that LOX positively regulates cell proliferation, migration and anchorage-independent growth.

CONCLUSIONS

Collectively, our data suggest that LOX functions as a tumor promoter in HGSOC and positively regulates several aspects of the metastatic cascade.

LOX expression in primary nasopharyngeal carcinoma: correlation with prognostic parameters and outcome

Lysyl oxidase (LOX) is an extracellular matrix-remodeling enzyme that plays important roles in tumor development and progression. To evaluate the prognostic value of LOX levels in primary nasopharyngeal carcinoma, we performed an immunohistochemical analysis using 233 tissue biopsy specimens from as many patients. We found that the extent of immunohistochemical LOX staining correlated inversely with the clinicopathological features and survival. High LOX expression correlated with decreases in 5-year survival, overall survival, distant metastasis-free survival and disease-free survival (p < 0.05). Cox regression analysis confirmed that LOX was a significant prognostic indicator of increased risk of 5-year mortality for all patients (hazard ratio [HR], 1.670; 95% confidence interval [95% CI], 1.033-2.701 [p < .005]). Higher LOX expression was also an independent predictor of poor prognosis in patients with nasopharyngeal carcinoma. These findings suggest LOX may be a new biomarker predictive of NPC prognosis and may also be a useful treatment target.

Suppression of Phosphatidylinositol 3-Kinase/Akt Signaling Attenuates Hypoxia-Induced Pulmonary Hypertension Through the Downregulation of Lysyl Oxidase

Lysyl oxidase (LOX) is a copper-dependent enzyme that catalyzes covalent cross-linking of collagen. In response to hypoxia, phosphatidylinositol 3-kinase (PI3K) pathway is activated and contributes to pulmonary arterial hypertension (PAH). However, potential role of LOX in hypoxia-induced PAH is poorly understood. In this study, we explored the mechanism responsible for the development of hypoxia-induced PAH. Potent inhibitors of PI3K/Akt and LOX, wortmannin and β-aminopropionitrile (β-APN), were administrated in rat model of hypoxia-induced PAH. The cross-linking of collagen was assessed by the determination of hydroxyproline. LOX, LOXL-1, LOXL-2, LOXL-3, LOXL-4, Akt, and phospho-Akt expression was detected by real-time polymerase chain reaction and western blot analysis. We observed that collagen cross-linking and LOX activity were elevated in hypoxia-exposed rat lung tissue, but these effects were reversed by β-APN and wortmannin. In addition, exposure to hypoxia enhanced mRNA and protein expression and activity of LOX and LOXL-1 in a PI3K/Akt-dependent manner and induced the development of PAH. After the administration of wortmannin, the upregulation of LOX and cross-linking of collagen were significantly reversed in hypoxia-exposed rat pulmonary artery tissue. Taken together, the present study demonstrated that the upregulation of LOX expression and collagen cross-linking is PI3K/Akt dependent in rat with hypoxia-induced PAH. Suppression of PI3K/Akt pathway may alleviate hypoxia-induced PAH through the downregulation of LOX.

Lysyl oxidase is associated with the epithelial-mesenchymal transition of gastric cancer cells in hypoxia

PURPOSE

It has been reported that lysyl oxidase (LOX) is a hypoxia-responsive factor and is associated with the malignant progression of carcinoma. The aim of this study was to clarify the relationship between the epithelial-mesenchymal transition (EMT) and LOX in gastric cancer cells under hypoxia.

METHODS

Two gastric cancer cell lines, OCUM-2MD3 and OCUM-12, were used in an in vitro study. The effect of LOX small interfering RNA (siRNA) on the EMT and motility of gastric cancer cells under hypoxic condition was analyzed by reverse transcription PCR, Western blot, a wound-healing assay, and an invasion assay. Correlations between LOX expression and the clinicopathological features of 544 patients with gastric carcinoma were examined immunohistochemically.

RESULTS

Hypoxic conditions increased the number of polygonal or spindle-shaped cells resulting from EMT in gastric cancer cells. The EMT of cancer cells induced by hypoxia was inhibited by treatment with LOX siRNA. The number of migrating and invading gastric cancer cells in hypoxia was significantly decreased by LOX knockdown. LOX siRNA significantly increased the E-cadherin level and decreased the vimentin level of gastric cancer cells. LOX expression was significantly associated with invasion depth, tumor differentiation, lymph node metastasis, lymphatic invasion, venous invasion, and peritoneal metastasis. Multivariable analysis revealed that LOX was an independent parameter for overall survival.

CONCLUSION

LOX affects the EMT of gastric cancer cells in hypoxic conditions. LOX expression is a useful prognostic factor for patients with gastric cancer.

Knockdown of TMEM14A expression by RNAi inhibits the proliferation and invasion of human ovarian cancer cells

Transmembrane protein 14A (TMEM14A) is a member of TMEMs. Alterations in TMEMs expression have been identified in several types of cancer, but the expression and function of TMEM14A in ovarian cancer is still unclear. Here, analysis on the expression data of the Cancer Genome Atlas (TCGA) ovarian serous cystadenocarcinoma (OV) dataset demonstrated the overexpression of TMEM14A in ovarian cancer tissues compared with normal tissues, which was consistent with our real-time PCR analysis on ovarian cancer and normal tissues collected from 30 patients. In addition, TMEM14A knockdown in two ovarian cancer cell lines, A2780 and HO-8910, reduced cell proliferation, causes cell cycle arrest and suppressed cell invasion. Moreover, silencing of TMEM14A notably repressed G1/S cell cycle transition and cell invasion via down-regulating the expression of cell cycle related proteins (Cyclin D1, Cyclin E and PCNA) and metastasis-related proteins (MMP-2 and MMP-9), respectively. TMEM14A knockdown significantly reduced the phosphorylation status of Smad2 and Smad3, downstream effectors of TGF-β signalling. In summary, these results indicate that TMEM14A has a pro-tumorigenic effect in ovarian cancer cells, suggesting an important role of this protein in ovarian cancer oncogenesis and metastasis.

4.1N suppresses hypoxia-induced epithelial-mesenchymal transition in epithelial ovarian cancer cells

Protein 4.1N (4.1N) is a member of the protein 4.1 family and is essential for the regulation of cell adhesion, motility and signaling. Previous studies have suggested that 4.1N may serve a tumor suppressor role. However, the molecular mechanisms remain unclear. In the current study, the role of 4.1N in the downregulation of hypoxia‑induced factor 1α (HIF‑1α) under hypoxic conditions and therefore the suppression of hypoxia induced epithelial‑mesenchymal transition (EMT) was investigated. The data were obtained from overexpressed and knockdown 4.1N epithelial ovarian cancer (EOC) cell lines. It was identified that 4.1N was capable of regulating the sub‑cellular localization and expression levels of HIF‑1α, by which 4.1N served a dominant role in the suppression of hypoxia‑induced EMT and associated genes. Collectively, the data of the current study identified 4.1N as an inhibitor of hypoxia‑induced tumor progression in EOC cells and highlighted its potential role in EOC therapy.

The Extracellular Matrix in Epithelial Ovarian Cancer - A Piece of a Puzzle

Epithelial ovarian cancer is the fifth leading cause of cancer-related deaths in women and the most lethal gynecological malignancy. Extracellular matrix (ECM) is an integral component of both the normal and tumor microenvironment. ECM composition varies between tissues and is crucial for maintaining normal function and homeostasis. Dysregulation and aberrant deposition or loss of ECM components is implicated in ovarian cancer progression. The mechanisms by which tumor cells induce ECM remodeling to promote a malignant phenotype are yet to be elucidated. A thorough understanding of the role of the ECM in ovarian cancer is needed for the development of effective biomarkers and new therapies.

Hypnosis and music interventions (HMIs) inactivate HIF-1: A potential curative efficacy for cancers and hypertension

Hypnosis and music interventions (HMIs) have shown positive influence on cancers for nearly 200years, but the underlying mechanisms were rarely explored systematically. The hypothesis suggests a potential curative efficacy of HMIs on cancers by inhibiting hypoxia inducible factor-1 (HIF-1), which is a key mediator of cancer development, especially under hypoxic conditions. HMIs are sufficient to attenuate the pain and anxiety degree of individuals, improve multiple psychological and physiological parameters, and consequently, lead to increased oxygen saturation in vivo. Furthermore, abundant oxygen in vivo inhibits the activation of HIF-1 and potentially blockades kinds of HIF-1-induced oncogenic signaling pathways. The hypothesized efficacy of HMIs is very similar to anti-cancer medicines targeting HIF-1. The implication of the hypothesis in preventing hypertension is also discussed. In summary, the hypothesis clearly suggests the potential involvement of the convenient, safe, non-pharmaceutical, and low-cost HMIs in preventing HIF-1-mediated diseases, including cancers and hypertension.

Retinoic acid aliphatic amide inhibits the AMPK-HIF-1α pathway in human ovarian cancer

Ovarian carcinoma the commonly observed gynecological cancers has a high mortality rate. In the present study effect of retinoic acid aliphatic amide (RACA) in ovarian cancer cells was investigated using proliferation, migration and invasion assays. Western blot was used to examine the Bcl-2, cleaved caspase 3, p-ERK, MMP-2, p-FAK, P-P38, p-AMPKα and HIF-1α protein expression. CoCl2 was used to induce HIF-1α expression in SKOV3ip. 1 and HEY-A8 cells. The results revealed that RACA treatment prompted cell proliferation, invasion and migration but inhibited apoptosis of SKOV3ip. 1 and HEY-A8 cells. RACA treatment also induced upregulation of Bcl-2 and MMP-2, activation of p-P38, p-ERK and p-FAK, inhibition of cleaved caspase 3. RACA treatment also caused upregulatation of HIF-1α in ovarian cells with the activation of p-AMPKα. Upregulation of HIF-1α expression in CoCl2-treated cancer cells resulted in decrease in SDHB. Thus RACA plays a key role in cell proliferation, invasion, migration and apoptosis of human ovarian carcinoma through AMPK-HIF-1α pathway.

Clinicopathological characteristics of gynecological cancer associated with hypoxia-inducible factor 1α expression: a meta-analysis including 6,612 subjects

BACKGROUND

Gynecological cancer is characterized by tumor hypoxia. However, the role of hypoxia-inducible factor 1α (HIF-1α) in gynecological cancer remains unclear.

METHOD

Electronic databases including Cochrane Library, PUBMED, Web of Knowledge and clinical trial registries were searched from inception through October 2014 for published, case-control studies assessing the association between HIF-1α and the clinicopathological characteristics of gynecological cancer. We pooled results from 59 studies using fixed or random-effects models and present results as odds ratios (ORs) following the PRISMA guidelines.

RESULTS

Our meta-analysis, which included 6,612 women, demonstrated that the expression of HIF-1α was associated with the clinicopathological characteristics of gynecological cancer. The expression of HIF-1α in cancer or borderline tissue was significantly higher than that in normal tissue (cancer vs. normal: odds ratio (OR) =9.59, 95% confidence interval (CI): 5.97, 15.39, p<0.00001; borderline vs. normal: OR=4.13, 95% (CI): 2.43, 7.02, p<0.00001; cancer vs. borderline: OR=2.70, 95% (CI): 1.69, 4.31, p<0.0001). The expression of HIF-1α in III-IV stage or lymph node metastasis was significantly higher than that in I-II stage or that without lymph node metastasis, respectively (OR=2.66, 95% (CI): 1.87,3.79, p<0.00001; OR= 3.98, 95% (CI): 2.10,12.89, p<0.0001). HIF-1α was associated with histological grade of cancer (Grade 3 vs. Grade 1: OR=3.77, 95% (CI): 2.76,5.16, p<0.00001; Grade 3 vs. Grade 2: OR=1.62, 95% (CI): 1.20,2.19, p=0.002; Grade 2 vs. Grade 1: OR=2.34, 95% (CI): 1.82,3.00, p<0.00001),5-years disease free survival (DFS) rates (OR=2.93, 95% (CI):1.43,6.01, p=0.001) and 5-years overall survival (OS) rates (OR=5.53, 95% (CI): 2.48,12.31, p<0.0001).

CONCLUSION

HIF-1α is associated with the malignant degree, FIGO stage, histological grade, lymph node metastasis, 5-years survival rate and recurrence rate of gynecological cancer. It may play an important role in clinical treatment and prognostic evaluation.

In vitro microtumors provide a physiologically predictive tool for breast cancer therapeutic screening

Many anti-cancer drugs fail in human trials despite showing efficacy in preclinical models. It is clear that the in vitro assays involving 2D monoculture do not reflect the complex extracellular matrix, chemical, and cellular microenvironment of the tumor tissue, and this may explain the failure of 2D models to predict clinical efficacy. We first optimized an in vitro microtumor model using a tumor-aligned ECM, a tumor-aligned medium, MCF-7 and MDA-MB-231 breast cancer spheroids, human umbilical vein endothelial cells, and human stromal cells to recapitulate the tissue architecture, chemical environment, and cellular organization of a growing and invading tumor. We assayed the microtumor for cell proliferation and invasion in a tumor-aligned extracellular matrix, exhibiting collagen deposition, acidity, glucose deprivation, and hypoxia. We found maximal proliferation and invasion when the multicellular spheroids were cultured in a tumor-aligned medium, having low pH and low glucose, with 10% fetal bovine serum under hypoxic conditions. In a 7-day assay, varying doses of fluorouracil or paclitaxel had differential effects on proliferation for MCF-7 and MDA-MB-231 tumor spheroids in microtumor compared to 2D and 3D monoculture. The microtumors exhibited a tumor morphology and drug response similar to published xenograft data, thus demonstrating a more physiologically predictive in vitro model.

LOX expression and functional analysis in astrocytomas and impact of IDH1 mutation

Lysyl oxidase (LOX) is involved in vital biological processes such as cell motility, cell signaling and gene regulation. Deregulation of this protein can contribute to tumor formation and progression. Although it is known that LOX is involved in invasion, proliferation and tumor migration in other types of tumors, studies of LOX in astrocytomas of different grades are scarce. The purpose of our study was to characterize LOX, BMP1 and HIF1A expression by real-time PCR in astrocytomas with WHO grades I to IV compared to non-neoplastic brain tissue. IDH1 mutational status was determined by PCR and sequencing. LOX protein expression was also analyzed by immunohistochemistry. LOX functional analyses were performed using siRNA knockdown and the specific inhibitor BAPN in two glioblastoma cell lines. The expression levels of LOX, BMP1 and HIF1A were correlated and analyzed according to IDH1 mutation status and to the clinical end-point of overall survival of glioblastoma patients. The results demonstrate that increased expression and activity of LOX, BMP1 and HIF1A were positively correlated with the malignant grade of astrocytomas. LOX protein expression also increased according to the degree of malignancy, with localization in the cytoplasm and nucleus and staining observed in endothelial cells. Glioblastoma with a mutation in IDH1 expressed lower levels of LOX in the nucleus, and IDH1-mutated cases showed lower LOX expression levels when compared to wild-type IDH1 cases. LOX knockdown and inhibition by BAPN in U87MG and A172 cell lines affected migration, invasion and soft agar colony formation. Taken together, these results corroborate the role of LOX in the migration, invasion and angiogenesis of astrocytomas. Furthermore, LOX expression is influenced by IDH1 mutational status. This work provides new insights for researchers aiming to design targeted therapies to control astrocytomas.

Hypoxia promotes HO-8910PM ovarian cancer cell invasion via Snail-mediated MT1-MMP upregulation

The molecular mechanisms of ovarian cancer cell invasion under hypoxia remain unclear. Here we employed a 3D collagen model and chick chorioallantoic membrane (CAM) invasion assay to explore the influence of hypoxia on ovarian cancer cell invasion. Hypoxia (both 1% O2 and CoCl2 150 and 250 µM) induced HO-8910PM ovarian cancer cell invasion in 3D collagen and collagenolysis determined by hydroxyproline. Pretreatment with a hypoxia inducible factor-1α inhibitor, YC-1, or MMP inhibitor, GM6001, significantly inhibited 3D collagen invasion and degradation and cell proliferation. Hypoxia stimulated both mRNA and protein expressions of membrane-type 1 matrix metalloproteinase (MT1-MMP) and promoted MT1-MMP translocation to the cell surface in an YC-1 sensitive manner. MT1-siRNA transfection inhibited hypoxia-induced invasion, proliferation, and collagen degradation of cells in 3D collagen. Hypoxia stimulated Snail mRNA and protein expression as well as translocation to nucleus in an YC-1 sensitive manner. Overexpression of Snail with a recombinant plasmid in HO-8910PM cells resulted in an enhanced invasion in 3D collagen. Transfection with Snail-specific siRNA significantly decreased MT1-MMP expression and 3D collagen invasion. Hypoxia-treated cells significantly broke the upper CAM surface of 11-day-old chick embryos and infiltrated interstitial tissue, completely blocked in the presence of YC-1 or GM6001, or after MT1-MMP siRNA or Snail siRNA transfection. Together, these data suggest that hypoxia promotes HO-8910PM ovarian cancer cell traffic through 3D matrix via Snail-mediated MT1-MMP upregulation, a possible molecular mechanism of ovarian cancer cell invasion under hypoxia.

Succinate dehydrogenase subunit B inhibits the AMPK-HIF-1α pathway in human ovarian cancer in vitro

Background

Ovarian carcinoma is one of the most common gynecological cancers with high mortality rates. Numerous evidences demonstrate that cancer cells undergo metabolic abnormality during tumorigenesis in tumor microenvironment and further facilitate tumor progression. Succinate dehydrogenase (SDH or Complex II) is one of the important enzymes in the tricarboxylic acid (TCA) cycle. Succinate dehydrogenase subunit B (SDHB) gene, which encodes one of the four subunits of SDH, has been recognized as a tumor suppressor. However the role of SDHB in ovarian cancer is still unclear.

Methods

Using the SDHB specific siRNA and overexpression plasmid, the expression of SDHB was silenced and conversely induced in ovarian cancer cell lines SKOV3 and A2780, respectively. The possible role of SDHB in ovarian cancer was investigated in vitro, using proliferation, migration and invasion assays. To explore the mechanism, proliferation and migration related proteins such as Bcl-2, cleaved caspase 3, p-ERK, MMP-2, and p-FAK were examined by western blot. P-P38, p-AMPKα, and HIF-1α were also examined by western blot. CoCl2 was used to induce HIF-1α expression in SKOV3 and A2780 cells.

Results

SDHB silencing promoted cell proliferation, invasion, and migration, but inhibited apoptosis of SKOV3 and A2780 cells. In contrast, overexpression of SDHB inhibited cell proliferation, invasion, migration, and promoted apoptosis in SKOV3 cells. It was observed that up-regulation of Bcl-2 and MMP-2, activation of p-P38, p-ERK, and p-FAK, inhibition of cleaved caspase 3 in SDHB-silenced cells. Meanwhile, decreased Bcl-2 and MMP-2, inhibition of p-P38, p-ERK, and p-FAK, activation of cleaved caspase 3 were shown in SDHB-overexpressed SKOV3 cells. HIF-1α, an essential factor in tumor progression, was up-regulated in SDHB-silenced cells with the activation of p-AMPKα and down-regulated in SDHB-overexpressed cancer cells with the decreased p-AMPKα. And SDHB was proved to be decreased due to upregulation of HIF-1α expression in CoCl2-treated cancer cells.

Conclusions

Our results firstly revealed that SDHB played a key role in cell proliferation, invasion, migration, and apoptosis of human ovarian carcinoma via AMPK-HIF-1α pathway. SDHB-overexpression might be a new approach to inhibit tumor progression in human ovarian carcinoma.

Electronic supplementary material

The online version of this article (doi:10.1186/s13048-014-0115-1) contains supplementary material, which is available to authorized users.