Evaluation of a hypoxia regulated gene panel in ovarian cancer

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.

Up-regulation of hypoxia-inducible factor antisense as a novel approach to treat ovarian cancer

Ovarian cancer (OC) is estimated to kill ~14,000 women in the United States in 2019. Current chemotherapies to treat OC initially show therapeutic efficacy but frequently drug resistance develops, at which point therapies with alternative targets are needed. Herein, we are describing a novel approach to sensitize these tumors to standard chemotherapies by increasing the transcription of hypoxia-inducible factor antisense.

Methods: Genome-wide Bru-seq analysis was performed to fully capture the nascent transcriptional signature of OC cells treated with the gp130 inhibitor, SC144. In vitro and in vivo analysis, including characterization of hypoxia and select protein expression, combination with standard of care chemotherapy and antitumor efficacy were performed to assess the biological activity of SC144 on induction of hypoxia in OC cells.

Results: Bru-seq analysis of OVCAR8 cells treated with SC144 shows upregulation of hypoxia related genes. In addition, transcription of hypoxia-inducible factor antisense (HIF1A-AS2) was induced that in turn reduced expression of HIF-1α and simultaneously increased expression of NDRG1. Furthermore, we observed decreased protein levels of EGFR, Met, c-Myc, cyclin D1, MMP-2, MMP-9 and TF, and phosphorylation of Src and P130-cas. SC144-induced alterations of HIF-1α and NDRG1 were also confirmed in prostate cancer cells. Ciclopirox olamine (CPX) induces a cellular transcriptional profile comparable to SC144, suggesting a similar cellular mechanism of action between these two compounds. In addition, SC144 sensitized OC cells to olaparib, carboplatin and cisplatin, and shows better in vivo efficacy than CPX.

Conclusion: Induction of hypoxic stress responses through inhibition of gp130 represents a novel approach to design effective anticancer treatments in combination with standard-of-care chemotherapy in OC and the efficacy reported here strongly supports their clinical development.

Analysis of tumour ecological balance reveals resource-dependent adaptive strategies of ovarian cancer

BACKGROUND

Despite treatment advances, there remains a significant risk of recurrence in ovarian cancer, at which stage it is usually incurable. Consequently, there is a clear need for improved patient stratification. However, at present clinical prognosticators remain largely unchanged due to the lack of reproducible methods to identify high-risk patients.

METHODS

In high-grade serous ovarian cancer patients with advanced disease, we spatially define a tumour ecological balance of stromal resource and immune hazard using high-throughput image and spatial analysis of routine histology slides. On this basis an EcoScore is developed to classify tumours by a shift in this balance towards cancer-favouring or inhibiting conditions.

FINDINGS

The EcoScore provides prognostic value stronger than, and independent of, known risk factors. Crucially, the clinical relevance of mutational burden and genomic instability differ under different stromal resource conditions, suggesting that the selective advantage of these cancer hallmarks is dependent on the context of stromal spatial structure. Under a high resource condition defined by a high level of geographical intermixing of cancer and stromal cells, selection appears to be driven by point mutations; whereas, in low resource tumours featured with high hypoxia and low cancer-immune co-localization, selection is fuelled by aneuploidy.

INTERPRETATION

Our study offers empirical evidence that cancer fitness depends on tumour spatial constraints, and presents a biological basis for developing better assessments of tumour adaptive strategies in overcoming ecological constraints including immune surveillance and hypoxia.

Circulating miRNA Profiling of Women at High Risk for Ovarian Cancer

Survival of epithelial ovarian cancer patients remains poor without significant change over many decades. There is a need to better identify women at high risk (HR) for ovarian cancer. We propose that miRNA dysregulation may play critical roles in the early stages of ovarian cancer development. Circulating miRNAs may represent an important biomarker in this context, and miRNA profiling of serum in women at HR compared to those at low risk (LR) may give insights in tumor initiation pathways. There is also rationale for a specific focus on regulation of the androgen and its related hypoxia pathways in tumor initiation. We hypothesized that subsets of these pathway related miRNAs may be downregulated in the HR state. Serum from four HR and five LR women were sequenced and analyzed for 2083 miRNAs. We found 137 miRNAs dysregulated between the HR and LR groups, of which 36 miRNAs were overexpressed in HR and the vast majority (101 miRNAs or 74%) downregulated in the HR, when compared to LR serum. mRNA targets for the differentially expressed miRNAs were analyzed from three different miRNA-mRNA interaction resources. Functional association analysis of hypoxia and androgen pathway mRNA targets of dysregulated miRNAs in HR serum revealed that all but one of the miRNAs that target 52 hypoxia genes were downregulated in HR compared to LR serum. Androgen pathway analysis also had a similar expression pattern where all but one of the miRNAs that target these 135 identified genes were downregulated in HR serum. Overall, there were 91 differentially expressed miRNA-mRNA pairings in the hypoxia analysis. In the androgen-related analysis, overall, there were 429 differentially expressed miRNA-mRNA pairs. Our pilot study suggests that almost all miRNAs that are conserved and/or validated are downregulated in the HR compared to LR serum. This study, which requires validation, suggests that, via miRNA dysregulation, involvement of both hypoxia and its related androgen pathways may contribute to the HR state. This pilot study is the first report to our knowledge that studies circulating miRNA profiling of HR and LR women.

Natural antisense transcript of hypoxia-inducible factor 1 regulates hypoxic cell apoptosis in epithelial ovarian cancer

Purpose

Hypoxia is a key stress that triggers apoptosis in various tumors, including epithelial ovarian cancer (EOC). Previous researches identified a hypoxia-upregulated lncRNA named "a natural antisense transcript of hypoxia-inducible factor 1 (aHIF)" in some tumors. However, the contribution of aHIF to EOC remains unclear. Here, we aimed to investigate the expression, function, and underlying mechanisms of aHIF in EOC progression under hypoxia.

Materials and methods

Expression levels of aHIF in EOC tissues were tested. In vitro and in vivo assays were conducted to explore the function and mechanism of aHIF in hypoxia-induced EOC progression.

Results

aHIF levels were increased in EOC tissues and were upregulated by hypoxia in EOC cells. Functional data revealed that aHIF knockdown accelerated cell apoptosis under hypoxia and inhibited EOC tumorigenesis and tumor growth in vivo. Additionally, aHIF overexpression inhibited cell apoptosis and enhanced cell proliferation under hypoxia in EOC. Mechanistically, the dysregulation of certain key mitochondrial apoptosis pathway-related genes, including Bcl-2, Bax, Caspase-7, and Caspase-9, may partially explain aHIF-regulated EOC apoptosis and growth under hypoxia.

Conclusion

These data provide the first convincing evidence that aHIF may inhibit EOC apoptosis and thereby promote tumor growth through activation of the mitochondrial apoptosis pathway under hypoxia. Our findings help clarify the role of lncRNA in hypoxia-induced EOC progression.

Review: Mechanotransduction in ovarian cancer: Shearing into the unknown

Ovarian cancer remains a deadly diagnosis with an 85% recurrence rate and a 5-year survival rate of only 46%. The poor outlook of this disease has improved little over the past 50 years owing to the lack of early detection, chemoresistance and the complex tumor microenvironment. Within the peritoneal cavity, the presence of ascites stimulates ovarian tumors with shear stresses. The stiff environment found within the tumor extracellular matrix and the peritoneal membrane are also implicated in the metastatic potential and epithelial to mesenchymal transition (EMT) of ovarian cancer. Though these mechanical cues remain highly relevant to the understanding and treatment of ovarian cancers, our current knowledge of their biological processes and their clinical relevance is deeply lacking. Seminal studies on ovarian cancer mechanotransduction have demonstrated close ties between mechanotransduction and ovarian cancer chemoresistance, EMT, enhanced cancer stem cell populations, and metastasis. This review summarizes our current understanding of ovarian cancer mechanotransduction and the gaps in knowledge that exist. Future investigations on ovarian cancer mechanotransduction will greatly improve clinical outcomes via systematic studies that determine shear stress magnitude and its influence on ovarian cancer progression, metastasis, and treatment.

Probing the prostate tumour microenvironment II: Impact of hypoxia on a cell model of prostate cancer progression

Approximately one in six men are diagnosed with Prostate Cancer every year in the Western world. Although it can be well managed and non-life threatening in the early stages, over time many patients cease to respond to treatment and develop castrate resistant prostate cancer (CRPC). CRPC represents a clinically challenging and lethal form of prostate cancer. Progression of CRPC is, in part, driven by the ability of cancer cells to alter their metabolic profile during the course of tumourgenesis and metastasis so that they can survive in oxygen and nutrient-poor environments and even withstand treatment. This work was carried out as a continuation of a study aimed towards gaining greater mechanistic understanding of how conditions within the tumour microenvironment impact on both androgen sensitive (LNCaP) and androgen independent (LNCaP-abl and LNCaP-abl-Hof) prostate cancer cell lines. Here we have applied technically robust and reproducible label-free liquid chromatography mass spectrometry analysis for comprehensive proteomic profiling of prostate cancer cell lines under hypoxic conditions. This led to the identification of over 4,000 proteins - one of the largest protein datasets for prostate cancer cell lines established to date. The biological and clinical significance of proteins showing a significant change in expression as result of hypoxic conditions was established. Novel, intuitive workflows were subsequently implemented to enable robust, reproducible and high throughput verification of selected proteins of interest. Overall, these data suggest that this strategy supports identification of protein biomarkers of prostate cancer progression and potential therapeutic targets for CRPC.

Potential Coagulation Factor-Driven Pro-Inflammatory Responses in Ovarian Cancer Tissues Associated with Insufficient O₂ and Plasma Supply

Tissue factor (TF) is a cell surface receptor for coagulation factor VII (fVII). The TF-activated fVII (fVIIa) complex is an essential initiator of the extrinsic blood coagulation process. Interactions between cancer cells and immune cells via coagulation factors and adhesion molecules can promote progression of cancer, including epithelial ovarian cancer (EOC). This process is not necessarily advantageous, as tumor tissues generally undergo hypoxia due to aberrant vasculature, followed by reduced access to plasma components such as coagulation factors. However, hypoxia can activate TF expression. Expression of fVII, intercellular adhesion molecule-1 (ICAM-1), and multiple pro-inflammatory cytokines can be synergistically induced in EOC cells in response to hypoxia along with serum deprivation. Thus, pro-inflammatory responses associated with the TF-fVIIa-ICAM-1 interaction are expected within hypoxic tissues. Tumor tissue consists of multiple components such as stromal cells, interstitial fluid, albumin, and other micro-factors such as proton and metal ions. These factors, together with metabolism reprogramming in response to hypoxia and followed by functional modification of TF, may contribute to coagulation factor-driven inflammatory responses in EOC tissues. The aim of this review was to describe potential coagulation factor-driven inflammatory responses in hypoxic EOC tissues. Arguments were extended to clinical issues targeting this characteristic tumor environment.

Validation of a Multiplexed Gene Signature Assay for Diagnosis of Canine Cancers from Formalin-Fixed Paraffin-Embedded Tissues

Background

Use of molecular‐based diagnostics for companion animals is impeded by availability of technology platforms, tissue acquisition requirements, and species‐specific reagents.

Hypothesis/Objectives

To validate a quantitative nuclease protection assay (qNPA) to simultaneously measure RNA expression of multiple genes in archived formalin‐fixed paraffin‐embedded (FFPE) tumors from dogs.

Animals

All tumor biopsy samples were collected retrospectively from surgical biopsies and in the care of veterinarians.

Methods

Retrospective case series. A qNPA 96‐well ArrayPlate was built using 30 canine‐specific genes, 5 housekeeping genes, positive and negative controls with qualified gene‐specific oligonucleotides. Pearson's correlation, coefficient of variation (CV), and multivariate analysis were used to determine analytical performance using 40 FFPE dog tumors. Once validated, 70 FFPE dog tumors were analyzed for differences in gene expression using hierarchical clustering and analysis of variance of log transformed data. Immunohistochemistry (IHC) was performed to correlate gene expression and protein expression in a subset of tumors.

Results

The assay was linear with decreasing sample input (R² = 0.978), reproducible within and between 96‐well plates (r = 0.988 and 0.95, respectively) and between different laboratories (CV = 0.96). Hierarchical cluster analysis showed grouping of tumors by histogenesis and oncogenes. Significant differences were found between BCl2, E2F transcription factor 1, MDM2, COX‐2, MET proto‐oncogene receptor kinase, and other biologically relevant gene expression in tumor subtypes. Immunohistochemistry confirmed protein expression.

Conclusions and Clinical Implications

Because this technology works reliably on FFPE specimens, it can help expedite the broad introduction of multiplexed genomic information for improved diagnostics and discovery of new targets for therapies in veterinary oncology.

MiRNA-486 regulates angiogenic activity and survival of mesenchymal stem cells under hypoxia through modulating Akt signal

MicroRNA-486 (miR-486) was first identified from human fetal liver cDNA library and validated as a regulator of hematopoiesis. Its roles in regulating the biological function of bone marrow-derived mesnechymal stem cells (BM-MSCs) under hypoxia have not been explored yet. In this study, we demonstrated that exposure to hypoxia upregulates miR-486 expression in BM-MSCs. Lentivirus-mediated overexpression of miR-486 resulted in increase of hepatocyte growth factor (HGF) and vascular endothelial growth factor(VEGF) in both mRNA and protein levels. MiR-486 expression also promotes proliferation and reduces apoptosis of BM-MSCs. Whereas MiR-486 knockdown downregulated the secretion of HGF and VEGF and induced apoptosis of BM-MSCs. Furthermore, PTEN-PI3K/AKT signaling was validated to be involved in changes of BM-MSC biological functions regulated by miR-486. These results suggested that MiR-486 mediated the hypoxia-induced angiogenic activity and promoted the proliferation and survival of BM-MSCs through regulating PTEN-PI3K/AKT signaling. These findings might provide a novel understanding of effective therapeutic strategy for hypoxic-ischemic diseases.