Hypoxia-inducible factor 1 and breast cancer metastasis

RhoB is regulated by hypoxia and modulates metastasis in breast cancer

BACKGROUND

RhoB is a Rho family GTPase that is highly homologous to RhoA and RhoC. RhoA and RhoC have been shown to promote tumor progression in many cancer types; however, a distinct role for RhoB in cancer has not been delineated. Additionally, several well-characterized studies have shown that small GTPases such as RhoA, Rac1, and Cdc42 are induced in vitro under hypoxia, but whether and how hypoxia regulates RhoB in breast cancer remains elusive.

AIMS

To determine whether and how hypoxia regulates RhoB expression and to understand the role of RhoB in breast cancer metastasis.

METHODS

We investigated the effects of hypoxia on the expression and activation of RhoB using real-time quantitative polymerase chain reaction and western blotting. We also examined the significance of both decreased and increased RhoB expression in breast cancer using CRISPR depletion of RhoB or a vector overexpressing RhoB in 3D in vitro migration models and in an in vivo mouse model.

RESULTS

We found that hypoxia significantly upregulated RhoB mRNA and protein expression resulting in increased levels of activated RhoB. Both loss of RhoB and gain of RhoB expression led to reduced migration in a 3D collagen matrix and invasion within a multicellular 3D spheroid. We showed that neither the reduction nor overexpression of RhoB affected tumor growth in vivo. While the loss of RhoB had no effect on metastasis, RhoB overexpression led to decreased metastasis to the lungs, liver, and lymph nodes of mice.

CONCLUSION

Our results suggest that RhoB may have an important role in suppressing breast cancer metastasis.

Comprehensive Proteomic Characterization Reveals Subclass-Specific Molecular Aberrations within Triple-negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer lacking targeted therapies. This is attributed to its high heterogeneity that complicates elucidation of its molecular aberrations. Here, we report identification of specific proteome expression profiles pertaining to two TNBC subclasses, basal A and basal B, through in-depth proteomics analysis of breast cancer cells. We observed that kinases and proteases displayed unique expression patterns within the subclasses. Systematic analyses of protein-protein interaction and co-regulation networks of these kinases and proteases unraveled dysregulated pathways and plausible targets for each TNBC subclass. Among these, we identified kinases AXL, PEAK1, and TGFBR2 and proteases FAP, UCHL1, and MMP2/14 as specific targets for basal B subclass, which represents the more aggressive TNBC cell lines. Our study highlights intricate mechanisms and distinct targets within TNBC and emphasizes that these have to be exploited in a subclass-specific manner rather than a one-for-all TNBC therapy.

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Proteome profiling reveals functionally distinct subclasses within TNBC

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Kinases and proteases underlie unique functional signatures among the subclasses

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Kinase-protease-centric networks highlight subclass-specific molecular rewiring

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Protein association dysregulations reveal TNBC subclass-specific protein targets

SLMP53-1 Inhibits Tumor Cell Growth through Regulation of Glucose Metabolism and Angiogenesis in a P53-Dependent Manner

The Warburg effect is an emerging hallmark of cancer, which has the tumor suppressor p53 as its major regulator. Herein, we unveiled that p53 activation by (S)-tryptophanol-derived oxazoloisoindolinone (SLMP53-1) mediated the reprograming of glucose metabolism in cancer cells and xenograft human tumor tissue, interfering with angiogenesis and migration. Particularly, we showed that SLMP53-1 regulated glycolysis by downregulating glucose transporter 1 (GLUT1), hexokinase-2 (HK2), and phosphofructokinase-2 isoform 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-3 (PFKFB3) (key glycolytic enzymes), while upregulating the mitochondrial markers synthesis of cytochrome c oxidase 2 (SCO2), cytochrome c oxidase subunit 4 (COX4), and OXPHOS mitochondrial complexes. SLMP53-1 also downregulated the monocarboxylate transporter 4 (MCT4), causing the subsequent reduction of lactate export by cancer cells. Besides the acidification of the extracellular environment, SLMP53-1 further increased E-cadherin and reduced metalloproteinase-9 (MMP-9) expression levels in both cancer cells and xenograft human tumor tissue, which suggested the interference of SLMP53-1 in extracellular matrix remodeling and epithelial-to-mesenchymal transition. Consistently, SLMP53-1 depleted angiogenesis, decreasing endothelial cell tube formation and vascular endothelial growth factor (VEGF) expression levels. SLMP53-1 also exhibited synergistic growth inhibitory activity in combination with the metabolic modulator dichloroacetic acid. These data reinforce the promising application of the p53-activating agent SLMP53-1 in cancer therapy, by targeting p53-mediated pathways of growth and dissemination.

The Regulation of the Metastatic Cascade by Physical Activity: A Narrative Review

The purpose of this narrative review is to provide an overview of the currently available knowledge about the mechanisms by which physical activity may affect metastatic development. The search terms exercise [Title/Abstract] AND metastasis [Title/Abstract] returned 222 articles on PUBMED on the 10 February 2019. After careful analysis of the abstracts, a final selection of 24 articles was made. Physical activity regulates the levels of metastatic factors in each of the five steps of the process. Moderate intensity exercise appears to prevent tumor spread around the body, among others, by normalizing angiogenesis, destroying circulating tumor cells, and decreasing endothelial cells permeability. Contrarily, high-intensity exercise seems to favor cancer dissemination, likely through excessive stress, which can be somewhat counteracted by an appropriate warm-up. In conclusion, chronic adaptations to moderate-intensity endurance exercise seem the most effective way to achieve a preventive effect of exercise on metastases. Altogether, the data gathered here reinforce the importance of encouraging cancer patients to perform moderate physical activity several times a week. To limit the undesired events thereof, a good knowledge of the patient's training level is important to establish an adapted exercise training program.

Tumor angiogenesis: causes, consequences, challenges and opportunities

Tumor vascularization occurs through several distinct biological processes, which not only vary between tumor type and anatomic location, but also occur simultaneously within the same cancer tissue. These processes are orchestrated by a range of secreted factors and signaling pathways and can involve participation of non-endothelial cells, such as progenitors or cancer stem cells. Anti-angiogenic therapies using either antibodies or tyrosine kinase inhibitors have been approved to treat several types of cancer. However, the benefit of treatment has so far been modest, some patients not responding at all and others acquiring resistance. It is becoming increasingly clear that blocking tumors from accessing the circulation is not an easy task to accomplish. Tumor vessel functionality and gene expression often differ vastly when comparing different cancer subtypes, and vessel phenotype can be markedly heterogeneous within a single tumor. Here, we summarize the current understanding of cellular and molecular mechanisms involved in tumor angiogenesis and discuss challenges and opportunities associated with vascular targeting.

Prediction of postoperative survival of triple-negative breast cancer based on nomogram model combined with expression of HIF-1α and c-myc

The aims of this study were to explore the expression of hypoxia inducible factor-1α (HIF-1α) and c-myc protein in triple-negative breast cancer (TNBC) and its clinical prognostic significance, and to establish a prediction model for postoperative survival of TNBC based on nomogram.A total of 87 patients with TNBC at the Department of Breast Surgery, Beijing Chaoyang Hospital, Capital Medical University from January 2012 to December 2015 were enrolled in this study. Immunohistochemistry was performed to detect the expression of HIF-1α and c-myc protein in breast cancer tissues. Cox regression analyses were performed to explore the correlation between HIF-1α/c-myc expression and clinical pathological parameters as well as prognosis. Receiver-operating characteristic curve was generated for cox multivariate analysis. A nomogram was generated based on the cox multivariate analysis, and a calibration curve was prepared for the nomogram to evaluate the consistency between the predicted probability of the nomogram and the actual observed probability. The stability of nomogram model was validated with an external cohort including 39 TNBC patients.The positive expression rates of HIF-1α and c-myc protein in breast cancer tissues were 41.4% (36/87) and 55.2% (48/87), respectively. HIF-1α expression was significantly correlated with age, tumor diameter, histological grade, lymph node status, and tumor TNM stage; c-myc expression was significantly associated with tumor diameter, histological grade, lymph node status, and tumor TNM stage. Cox univariate and multivariate analyses showed that HIF-1α and c-myc protein expression, histological grade, lymph node status, and tumor TNM stage were the independent risk factors for postoperative survival in TNBC patients. The AUC of prediction model was 0.843 (0.809-0.887). The nomogram could predict the probability of 3-year disease-free survival according to each patient's condition. The calibration curve displayed good agreement of the predicted probability with the actual observed probability, indicating that the nomogram model had great value of prediction. The external validation indicated the prediction model had good stability.HIF-1α-positive expression, c-myc positive expression, histological grade III, lymph node positive, and TNM stage III tumors suggested that TNBC patients had a poor prognosis. This prediction model can be used to predict postoperative survival of TNBC.

Notch and breast cancer metastasis: Current knowledge, new sights and targeted therapy

Breast cancer is the most common type of invasive cancer in females and metastasis is one of the major causes of breast cancer-associated mortality. Following detachment from the primary site, disseminated tumor cells (DTCs) enter the bloodstream and establish secondary colonies during the metastatic process. An increasing amount of studies have elucidated the importance of Notch signaling in breast cancer metastasis; therefore, the present review focuses on the mechanisms by which Notch contributes to the occurrence of breast cancer DTCs, increases their motility, establishes interactions with the tumor microenvironment, protects DTCs from host surveillance and finally facilitates secondary colonization. Identification of the underlying mechanisms of Notch-associated breast cancer metastasis will provide additional insights that may contribute towards the development of novel Notch-targeted therapeutic strategies, which may aid in reducing metastasis, culminating in an improved patient prognosis.

The Milk Protein Alpha-Casein Suppresses Triple Negative Breast Cancer Stem Cell Activity Via STAT and HIF-1alpha Signalling Pathways in Breast Cancer Cells and Fibroblasts

Triple negative breast cancer (TNBC) is the most lethal breast cancer subtype. Extended periods of lactation protect against breast cancer development, but the mechanisms underlying this protection are unknown. We examined the effects of the milk protein alpha-casein over expression in the triple negative MDA-MB-231 breast cancer cell line. The effects of recombinant alpha-casein added exogenously to MDA-MB-231 breast cancer cells, and immortalised human fibroblasts were also investigated. We used transcriptional reporters to understand the signalling pathways downstream of alpha-casein in breast cancer cells and these fibroblasts that were activated by breast cancer cells. To extend our findings to the clinical setting, we analysed public gene expression datasets to further understand the relevance of these signalling pathways in triple negative breast cancer cells and patient samples. Finally, we used small molecular inhibitors to target relevant pathways and highlight these as potential candidates for the treatment of TN breast cancer. High levels of alpha-casein gene expression were predictive of good prognosis across 263 TNBC patient tumour samples. Alpha-casein over expression or exogenous addition reduces cancer stem cell (CSC) activity. HIF-1alpha was identified to be a key downstream target of alpha-casein, in both breast cancer cells and activated fibroblasts, and STAT transcription factors to be upstream of HIF-1alpha. Interestingly, HIF-1alpha is regulated by STAT3 in breast cancer cells, but STAT1 is the regulator of HIF-1alpha in activated fibroblasts. In analysis of 573 TNBC patient samples, alpha-casein expression, inversely correlated to HIF-1alpha, STAT3 and STAT1. STAT1 and STAT3 inhibitors target HIF-1alpha signalling in activated fibroblasts and MDA-MB-231 breast cancer cells respectively, and also abrogate CSC activities. Our findings provide an explanation for the protective effects of lactation in TNBC. Clinical data correlates high alpha-casein expression with increased recurrence-free survival in TNBC patients. Mechanistically, alpha-casein reduces breast cancer stem cell activity in vitro, and STAT3 and STAT1 were identified as regulators of pro-tumorigenic HIF-1alpha signalling in breast cancer cells and fibroblasts respectively.

HIF1α/PD-L1 axis mediates hypoxia-induced cell apoptosis and tumor progression in follicular thyroid carcinoma

Background

Hypoxia-inducible factor 1α (HIF-1α) and programmed cell death-1 protein ligand 1 (PD-L1) are implicated in the metastasis and progression processes of multiple cancers. Hypoxia selectively elevates PD-L1 expression via HIF1α activation in several solid tumors; however, the regulatory effect of HIF1α on PD-L1 in the pathogenesis of follicular thyroid cancer (FTC) remains unclear. This study aims to investigate the regulatory effect of HIF1α on PD-L1 and their potential roles in FTC pathogenesis.

Methods

Spearman correlation analysis was performed to clarify the relationships between HIF1α and PD-L1 expressions and the clinicopathologic characteristics. The expressions of HIF1α and PD-L1 at mRNA and protein levels were analyzed by qRT-PCR and Western blot. Hypoxia induction and cell transfection were conducted in FTC cells. TUNEL and Annexin V staining were used to detect the cell apoptosis. FTC xenograft tumor models were generated to evaluate the roles of HIF1α and PD-L1 in vivo.

Results

Here, we found that the expressions of HIF1α and PD-L1 were significantly increased in FTC tissues and were correlated with the FTC clinicopathologic features, such as the tumor size, T stage, TNM staging, and metastasis. In FTC cells, hypoxia-induced increased HIF1α and PD-L1 expression. Knockdown of HIF1α inhibits hypoxia-induced PD-L1 expression and cells apoptosis. Moreover, inhibition of HIF1α or PD-L1 significantly delays tumor growth and metastasis in vivo.

Conclusion

Hypoxia could promote FTC progression by upregulating HIF1α and PD-L1, which could serve as the molecular targets for FTC treatment.

Emerging Roles of the Endoplasmic Reticulum Associated Unfolded Protein Response in Cancer Cell Migration and Invasion

Endoplasmic reticulum (ER) proteostasis is often altered in tumor cells due to intrinsic (oncogene expression, aneuploidy) and extrinsic (environmental) challenges. ER stress triggers the activation of an adaptive response named the Unfolded Protein Response (UPR), leading to protein translation repression, and to the improvement of ER protein folding and clearance capacity. The UPR is emerging as a key player in malignant transformation and tumor growth, impacting on most hallmarks of cancer. As such, the UPR can influence cancer cells’ migration and invasion properties. In this review, we overview the involvement of the UPR in cancer progression. We discuss its cross-talks with the cell migration and invasion machinery. Specific aspects will be covered including extracellular matrix (ECM) remodeling, modification of cell adhesion, chemo-attraction, epithelial-mesenchymal transition (EMT), modulation of signaling pathways associated with cell mobility, and cytoskeleton remodeling. The therapeutic potential of targeting the UPR to treat cancer will also be considered with specific emphasis in the impact on metastasis and tissue invasion.

RETRACTED: Sinomenine inhibits proliferation, migration, invasion and promotes apoptosis of prostate cancer cells by regulation of miR-23a

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Given the comments of Dr Elisabeth Bik regarding this article “In almost all papers, Western blot panels within the same figure, and across figures and papers, appear to share the same background, while the bands are regularly spaced, all have similar rounded edges without the usual smudges and specks, and with some bands showing a recognizable “jumping sardine” shape”, the journal requested the authors to provide the raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.

Profiling of nuclear copper-binding proteins under hypoxic condition

Under hypoxic condition, copper (Cu) accumulates in cell nuclei, and regulates the activity of hypoxia-inducible factor-1 (HIF-1) through Cu-binding proteins (CuBPs). To understand the CuBPs in the nucleus, proteomic approach was undertaken to explore the dynamic changes of the CuBPs in response to hypoxia. Human umbilical vein endothelial cells (HUVECs) were treated with dimethyloxalylglycine in a final concentration of 100 μM for 4 h to induce hypoxia, resulting in the accumulation of HIF-1α and Cu in the nucleus. Cu immobilized metal affinity chromatography was applied to extract the CuBPs, followed by identification using nanoliter-liquid chromatograpy combined with quadrupole time of flight tandem mass spectrometry (nanoLC-Q-TOF-MS/MS). There were 278 nuclear proteins that were found as CuBPs in the induced hypoxic group in contrast to 218 CuBPs in the control group. Functional annotation of these proteins in gene ontology category revealed that proteins participating in negative regulation of transcription from RNA polymerase II promoter were dramatically enriched by induced hypoixc treatment. Label-free quantitative proteomic approach identified quantitative changes of nuclear proteome; of 17 differentially expressed proteins, 8 were downregulated and 9 were upregulated in the induced hypoxic nuclei. Four of the 17 proteins were CuBPs, including ILF2 and TRA2B, both were downregulated, and LMNA and HSPB1, both were upregulated. We confirmed the protein change of ALB, LMNA and HSPB1 (HSP27) in real hypoxia, and suggested that the identified CuBPs could be the target for further study of Cu regulation of HIF-1 activity in the nucleus.

Tissue-engineered nanoclay-based 3D in vitro breast cancer model for studying breast cancer metastasis to bone

Breast cancer (BrCa) preferentially spreads to bone and colonises within the bone marrow to cause bone metastases. To improve the outcome of patients with BrCa bone metastasis, we need to understand better the mechanisms underlying bone metastasis. Researchers have relied heavily upon in vivo xenografts due to limited availability of human bone metastasis samples. A significant limitation of these is that they do not have a human bone microenvironment. To address this issue, we have developed a nanoclay-based 3D in vitro model of BrCa bone metastasis using human mesenchymal stem cells (MSCs) and human BrCa cells mimicking late stage of BrCa pathogenesis at the metastatic site. This 3D model can provide a microenvironment suitable for cell-cell and cell-matrix interactions whilst retaining the behaviour of BrCa cells with different metastasis potential (i.e., highly metastatic MDA-MB-231 and low metastatic MCF-7) as shown by the production of alkaline phosphatase and matrix metalloproteinase-9. The sequential culture of MSCs with MCF-7 exhibited 3D tumouroids formation and also occurrence of mesenchymal to epithelial transition of cancer metastasis as evidenced by gene expression and immunocytochemistry. The unique and distinct behaviour of highly metastatic MDA-MB-231 and the low metastatic MCF-7 was observed at the bone metastasis site. The changes to migratory capabilities and invasiveness in MDA-MB-231 in comparison with tumour growth with MCF-7 was observed. Together, a novel bone-mimetic 3D in vitro BrCa model has been developed that could be used to study mechanisms governing the later stage of cancer pathogenesis in bone.

Relative hypoxia and oxidative stress in spleen lymphocytes of immunized Balb/c mice as indicated by HIF-1α, HIF-2α, Nrf2 expression, and glutathione peroxidase activity

Background: Lymphocytes activated by immunization must increase their metabolism to meet the energy requirements for mitosis, differentiation, and protein synthesis, which may subject the cell to conditions of relative hypoxia and oxidative stress. This study was conducted to investigate the increase in the levels of transcription factors involved in both conditions.Methods: Male Balb/c mice were divided into the following four groups, each consisting of six animals: the control and three experimental groups. The experimental groups were immunized by injection of 0.2 ml of 2% sheep red blood cells (SRBC) suspended in phosphate-buffered saline (PBS). Lymphocytes were harvested from the spleens of each group at time intervals of 24-, 48-, and 72-h post-immunization. The buffy coat from splenocytes was separated using Ficoll Histopaque as the medium. The lymphocytes were separated from adherent cells by incubating the purified splenocytes in microtubes for 2-h. Cells were lysed by three freeze–thaw cycles (−80°C and 37°C) and used to analyze the levels of HIF-1α and HIF-2α (mRNA and protein), Nrf2 (protein), and glutathione peroxidase (GPx) activity.Results: The treatment caused an increase in GPx activity and HIF-1α protein concentration 24-h post-immunization, whereas the HIF-1α mRNA levels remained static. Elevated Nrf2 protein levels were detected within 48-h after treatment. Meanwhile, the HIF-2α mRNA and protein levels increased within72-h after immunization.Conclusion: Immunization with SRBC suspension induced relative hypoxia, elevated reactive oxygen species (ROS), and oxidative stress in the lymphocytes as indicated by the increase in both HIF-1α and HIF-2α protein and mRNA levels, GPx activity, and Nrf2 protein levels.

Polymorphisms in HIFs and breast cancer sutarsceptibility in Chinese women: a case-control study

Hypoxia-inducible factors (HIFs) play a crucial role in cancer progression. Several epidemiological studies have demonstrated that HIFs polymorphisms can influence the susceptibility of multiple cancers. However, the relationship of HIFs polymorphisms (rs11549467 and rs17039192) and breast cancer (BC) risk was still unknown. Thus, we performed a case-control study based on 560 BC patients and 583 healthy controls to explore the association between them. Our results indicated a boardline connection between HIF-1 rs11549467 and BC risk (AG compared with GG: OR = 1.61, 95% CI = 1.05-2.49, P=0.03; AG + AA compared with GG: OR = 1.64, 95% CI = 1.08-2.51, P=0.02; AG compared with GG + AA: OR = 1.61, 95% CI = 1.04-2.48, P=0.03; OR = 1.64, 95% CI = 1.09-2.45, P=0.02), while HIF-2 rs17039192 had no influence on breast cancer. Considered the comparison of sample size and potential heterogeneity of previous case-control studies, we concluded that HIF-1 rs11549467 has a marginal effect on BC risk. Further well-designed studies with larger sample size were required.

Organotypic microfluidic breast cancer model reveals starvation-induced spatial-temporal metabolic adaptations

BACKGROUND

Ductal carcinoma in situ (DCIS) is the earliest stage of breast cancer. During DCIS, tumor cells remain inside the mammary duct, growing under a microenvironment characterized by hypoxia, nutrient starvation, and waste product accumulation; this harsh microenvironment promotes genomic instability and eventually cell invasion. However, there is a lack of biomarkers to predict what patients will transition to a more invasive tumor or how DCIS cells manage to survive in this harsh microenvironment.

METHODS

In this work, we have developed a microfluidic model that recapitulates the DCIS microenvironment. In the microdevice, a DCIS model cell line was grown inside a luminal mammary duct model, embedded in a 3D hydrogel with mammary fibroblasts. Cell behavior was monitored by confocal microscopy and optical metabolic imaging. Additionally, metabolite profile was studied by NMR whereas gene expression was analyzed by RT-qPCR.

FINDINGS

DCIS cell metabolism led to hypoxia and nutrient starvation; revealing an altered metabolism focused on glycolysis and other hypoxia-associated pathways. In response to this starvation and hypoxia, DCIS cells modified the expression of multiple genes, and a gradient of different metabolic phenotypes was observed across the mammary duct model. These genetic changes observed in the model were in good agreement with patient genomic profiles; identifying multiple compounds targeting the affected pathways. In this context, the hypoxia-activated prodrug tirapazamine selectively destroyed hypoxic DCIS cells.

INTERPRETATION

The results showed the capacity of the microfluidic model to mimic the DCIS structure, identifying multiple cellular adaptations to endure the hypoxia and nutrient starvation generated within the mammary duct. These findings may suggest new potential therapeutic directions to treat DCIS. In summary, given the lack of in vitro models to study DCIS, this microfluidic device holds great potential to find new DCIS predictors and therapies and translate them to the clinic.

PI3K/Akt and HIF‑1 signaling pathway in hypoxia‑ischemia (Review)

Hypoxia-ischemia (H-I) is frequently observed in perinatal asphyxia and other diseases. It can lead to serious cardiac injury, cerebral damage, neurological disability and mortality. Previous studies have demonstrated that the phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt) signaling pathway, which regulates a wide range of cellular functions, is involved in the resistance response to H-I through the activation of proteins associated with survival and inactivation of apoptosis-associated proteins. It can also regulate the expression of hypoxia-induced factor-1α (HIF-1α). HIF-1α can further regulate the expression of downstream proteins involved in glucose metabolism and angiogenesis, such as vascular endothelial growth factor and erythropoietin, to facilitate ischemic adaptation. Notably, HIF-1α may also induce detrimental effects. The effects of HIF-1 on ischemic outcomes may be dependent on the H-I duration, animal age and species. Thus, further investigation of the PI3K/Akt signaling pathway may provide further insights of the potential targets for treating diseases accompanied by H-I.

Hypermethylated gene ANKDD1A is a candidate tumor suppressor that interacts with FIH1 and decreases HIF1α stability to inhibit cell autophagy in the glioblastoma multiforme hypoxia microenvironment

Ectopic epigenetic mechanisms play important roles in facilitating tumorigenesis. Here, we first demonstrated that ANKDD1A is a functional tumor suppressor gene, especially in the hypoxia microenvironment. ANKDD1A directly interacts with FIH1 and inhibits the transcriptional activity of HIF1α by upregulating FIH1. In addition, ANKDD1A decreases the half-life of HIF1α by upregulating FIH1, decreases glucose uptake and lactate production, inhibits glioblastoma multiforme (GBM) autophagy, and induces apoptosis in GBM cells under hypoxia. Moreover, ANKDD1A is highly frequently methylated in GBM. The tumor-specific methylation of ANKDD1A indicates that it could be used as a potential epigenetic biomarker as well as a possible therapeutic target.

Tualang Honey Reduced Neuroinflammation and Caspase-3 Activity in Rat Brain after Kainic Acid-Induced Status Epilepticus

The protective effect of tualang honey (TH) on neuroinflammation and caspase-3 activity in rat cerebral cortex, cerebellum, and brainstem after kainic acid- (KA-) induced status epilepticus was investigated. Male Sprague-Dawley rats were pretreated orally with TH (1.0 g/kg body weight) five times at 12 h intervals. KA (15 mg/kg body weight) was injected subcutaneously 30 min after last oral treatment. Rats were sacrificed at 2 h, 24 h, and 48 h after KA administration. Neuroinflammation markers and caspase-3 activity were analyzed in different brain regions 2 h, 24 h, and 48 h after KA administration. Administration of KA induced epileptic seizures. KA caused significant (p < 0.05) increase in the level of tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), glial fibrillary acidic protein (GFAP), allograft inflammatory factor 1 (AIF-1), and cyclooxygenase-2 (COX-2) and increase in the caspase-3 activity in the rat cerebral cortex, cerebellum, and brainstem at multiple time points. Pretreatment with TH significantly (p < 0.05) reduced the elevation of TNF-α, IL-1β, GFAP, AIF-1, and COX-2 level in those brain regions at multiple time points and attenuated the increased caspase-3 activity in the cerebral cortex. In conclusion, TH reduced neuroinflammation and caspase-3 activity after kainic acid- (KA-) induced status epilepticus.

Hypoxia promotes breast cancer cell invasion through HIF-1α-mediated up-regulation of the invadopodial actin bundling protein CSRP2

Hypoxia is a common feature of solid tumours that promotes invasion and metastatic dissemination. Invadopodia are actin-rich membrane protrusions that direct extracellular matrix proteolysis and facilitate tumour cell invasion. Here, we show that CSRP2, an invadopodial actin bundling protein, is upregulated by hypoxia in various breast cancer cell lines, as well as in pre-clinical and clinical breast tumour specimens. We functionally characterized two hypoxia responsive elements within the proximal promoter of CSRP2 gene which are targeted by hypoxia-inducible factor-1 (HIF-1) and required for promoter transactivation in response to hypoxia. Remarkably, CSRP2 knockdown significantly inhibits hypoxia-stimulated invadopodium formation, ECM degradation and invasion in MDA-MB-231 cells, while CSRP2 forced expression was sufficient to enhance the invasive capacity of HIF-1α-depleted cells under hypoxia. In MCF-7 cells, CSRP2 upregulation was required for hypoxia-induced formation of invadopodium precursors that were unable to promote ECM degradation. Collectively, our data support that CSRP2 is a novel and direct cytoskeletal target of HIF-1 which facilitates hypoxia-induced breast cancer cell invasion by promoting invadopodia formation.

The role of HIF-1α in chemo-/radioresistant tumors

Chemo-/radioresistance is a major obstacle in clinical oncology. The precise failure mechanisms of chemo-/radioresistance are multifactorial failures. It is now widely accepted that a tumor hypoxia microenvironment contributes significantly to chemo-/radioresistance. Hypoxia is the most common and obvious neoplastic microenvironment and is due to the rapid proliferation of tumor cells. HIF-1α is a principal molecular mediator of adaptability to hypoxia in tumor cells. HIF-1α activation leads to the transcription of a plethora of target genes that promote physiological changes associated with chemo-/radioresistance, including increasing the ability of DNA repair, the inhibition of apoptosis, and alterations of the cellular metabolism. Moreover, recent findings suggest that HIF-1α-activated autophagy is a crucial factor in the promotion of cell survival under the distressed microenvironment, thereby leading to the chemo-/radioresistance. This chapter presents an overview of the role of HIF-1α in chemo-/radioresistance of tumor cells.

Micropassage-embedding composite hydrogel fibers enable quantitative evaluation of cancer cell invasion under 3D coculture conditions

Cell migration and invasion are of significant importance in physiological phenomena, including wound healing and cancer metastasis. Here we propose a new system for quantitatively evaluating cancer cell invasion in a three-dimensional (3D), in vivo tissue-like environment. This system uses composite hydrogel microfibers whose cross section has a relatively soft micropassage region and that were prepared using a multilayered microfluidic device; cancer cells are encapsulated in the core and fibroblasts are seeded in the shell regions surrounding the core. Cancer cell proliferation is guided through the micropassage because of the physical restriction imposed by the surrounding solid shell regions. Quantitative analysis of cancer cell invasion is possible simply by counting the cancer cell colonies that form outside the fiber. This platform enables the evaluation of anticancer drug efficacy (cisplatin, paclitaxel, and 5-fluorouracil) based on the degree of invasion and the gene expression of cancer cells (A549 cells) with or without the presence of fibroblasts (NIH-3T3 cells). The presented hydrogel fiber-based migration assays could be useful for studying cell behaviors under 3D coculture conditions and for drug screening and evaluation.

Euterpe oleracea extract inhibits tumorigenesis effect of the chemical carcinogen DMBA in breast experimental cancer

Background

Among the processes involved in the breast tumor microenvironment, angiogenesis and inflammation play a central role, and the main factors of these processes are the vascular endothelial growth factor (VEGF), cyclooxygenase 2 (COX-2) and macrophages. Recently, the extract of Euterpe oleracea (açaí), a fruit that is widely found in the Amazon region, already showed antitumorigenic effects in vitro in human breast cancer cell lines. The present study aimed to investigate the effect of açaí on breast cancer using a chemically DMBA (7,12-dimethylbenzanthracene) experimental model.

Methods

One day after initiation of treatment with açaí, mammary carcinogenesis was induced in female Wistar rats using a subcutaneous injection of 25 mg/kg of DMBA in the mammary gland. Forty rats were randomized into two groups: treated with 200 mg/kg of either açaí extract or vehicle, via gastric tube for 16 consecutive weeks. After treatment, the tumor was collected for macroscopic, histological and immunohistochemical (VEGF, vascular endothelial growth factor receptor 2 -VEGFR-2, COX-2 and matrix metalloproteinase -MMP-9) analyses; peritoneal fluid was subjected to flow cytometry (F4–80/MAC-2+) and ELISA immunoassay (VEGF, prostaglandin E₂ -PGE₂ and interleukin-10 -IL-10). Heart, liver and kidney samples were collected for histological analysis.

Results

After 16 weeks of induction, the mammary carcinoma was confirmed by macroscopic and histological evaluation. Survival analysis indicates that açaí increased the survival (P = .0002, long-rank test) and reduced the deaths number (P = .0036, Chi-square test). Açaí treatment decreased the number of inflammatory cells and macrophage positive cells (Mac-2 + F4–80+), as well as promoting a reduction in immunostaining of VEGF, VEGFR-2 and COX-2. The açaí group also exhibited lower concentrations of PGE₂, VEGF and IL-10 compared to the control. The histopathological results of the liver and kidneys showed protective effect of açaí, since in the control group, there was an increase in fibrosis, atypical cells and hemorrhagic microenvironment.

Conclusion

The results of this study demonstrated the antiangiogenic and anti-inflammatory potential of açaí, like due to the decreases of the number of activated macrophages, resulting in the inhibition of DMBA carcinogenicity in breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2183-z) contains supplementary material, which is available to authorized users.

USP28 Deficiency Promotes Breast and Liver Carcinogenesis as well as Tumor Angiogenesis in a HIF-independent Manner

Recent studies suggest that the ubiquitin-specific protease USP28 plays an important role in cellular repair and tissue remodeling, which implies that it has a direct role in carcinogenesis. The carcinogenic potential of USP28 was investigated in a comprehensive manner using patients, animal models, and cell culture. The findings demonstrate that overexpression of USP28 correlates with a better survival in patients with invasive ductal breast carcinoma. Mouse xenograft experiments with USP28-deficient breast cancer cells also support this view. Furthermore, lack of USP28 promotes a more malignant state of breast cancer cells, indicated by an epithelial-to-mesenchymal (EMT) transition, elevated proliferation, migration, and angiogenesis as well as a decreased adhesion. In addition to breast cancer, lack of USP28 in mice promoted an earlier onset and a more severe tumor formation in a chemical-induced liver cancer model. Mechanistically, the angio- and carcinogenic processes driven by the lack of USP28 appeared to be independent of HIF-1α, p53, and 53BP1.Implications: The findings of this study are not limited to one particular type of cancer but are rather applicable for carcinogenesis in a more general manner. The obtained data support the view that USP28 is involved in tumor suppression and has the potential to be a prognostic marker. Mol Cancer Res; 16(6); 1000-12. ©2018 AACR.

Prognostic value of plasma levels of HIF-1a and PGC-1a in breast cancer

Cellular adaptive mechanisms are crucial for tumorigenesis and a common feature in solid tumor progression. Hypoxia-inducible factor-1α (HIF-1α) facilitates the biological response to hypoxia, advancing angiogenesis and metastatic potential of the tumor. The peroxisome proliferator–activated receptor γ coactivators 1α (PGC-1α) enhances mitochondrial biogenesis, favored by migratory/invasive cancer cells. We conducted a prospective, long-term follow up study to determine whether HIF-1α and PGC-1α can be implemented as predictive biomarker in breast cancer. HIF-1α and PGC-1α plasma concentrations were measured in patients and in healthy controls by enzyme linked immune sorbent assay. Breast cancer patients had significantly higher HIF-1α and PGC-1α levels, which correlated with clinicopathological features, overall with more aggressive cancer characteristics. Disease free and overall survival of breast cancer patients with high HIF-1α and PGC-1α were significantly poorer than in patients with low plasma levels. In multivariate analysis, high amount of PGC-1α showed independent prognostic value. Our data suggests that HIF-1α and PGC-1α may be promising, noninvasive, biomarkers with a high potential for future clinical implication to identify subgroups of patients with poorer prognosis and to indicate early, subclinical metastasis.

Downregulation of HIF-2α Reverse the Chemotherapy Resistance of Lung Adenocarcinoma A549 Cells to Cisplatin

Background

Cisplatin (DDP)-based systemic chemotherapy has been widely used in the treatment of postoperative or advanced NSCLC patients, however, its effective rate is only 14~40%. HIF-2α can upregulate drug-resistant-related genes expression and lead to chemotherapy resistance in many tumors. However, little is known about the relationship between HIF-2α and chemotherapy resistance of lung cancer cells.

Material/Methods

In our study, the siRNA expression vectors targeting the HIF-2α gene were designed, constructed, and transfected into A549 cells. MTT assay and western blot analysis of P-glycoprotein 1 (P-gp) were used to explore the transfer influence of HIF-2α gene silencing on the A549 cells in the cisplatin-based chemotherapy resistance.

Results

After transfection with the siRNA_HIF-2α into A549 cells, mRNA and protein expression of HIF-2α were downregulated. At the same time, expression of P-gp decreased significantly. Furthermore, the sensitivity to cisplatin significantly increased.

Conclusions

The constructed siRNA expression vectors can effectively suppress the expression of HIF-2α and P-gp, which then can reverse the chemotherapy resistance of A549 cells.

Hypoxia-inducible factor prolyl hydroxylase 2 (PHD2) is a direct regulator of epidermal growth factor receptor (EGFR) signaling in breast cancer

Clinical studies in breast cancer suggest important associations between intratumoral hypoxia, the upregulation of epidermal growth factor receptor (EGFR or HER1), hypoxia-inducible factor 1α (HIF-1α), and reduced patient survival. However, direct molecular links between EGFR and the hypoxia signaling system are not yet established. Since the oxygen sensor hypoxia-inducible factor prolyl hydroxylase 2 (PHD2) is considered to be the main HIF-1α regulator, we hypothesized that PHD2 and EGFR may be interconnected at the molecular level. By analyzing samples from 313 breast cancer patients, we found that EGFR is a first clinicopathological parameter positively correlating with PHD2. Mechanistically, we identified PHD2 as a direct binding partner of EGFR and show that PHD2 regulates EGFR stability as well as its subsequent signaling in breast carcinoma cells. Overall, we introduce for the first time the direct crosstalk between the oxygen sensor PHD2 and EGFR-mediated tumorigenesis in breast cancer.

High Altitude and Cancer Mortality

Thiersch, Markus, and Erik R. Swenson. High altitude and cancer mortality. High Alt Med Biol 19:116-123, 2018.-Humans living at high altitude (HA) are exposed to chronic (hypobaric) hypoxia. Despite the permanent stress of hypoxic exposure, humans populating HA areas have reduced cancer mortality over a broad spectrum of cancer types. In fact, the majority of the physiological adaptive processes at HA occurring in response to hypoxia might be the driving force for reduced cancer mortality at HA. In this review, we summarize epidemiological and animal studies that compare cancer incidence and cancer mortality between HA and low altitude or between hypoxia and normoxia, respectively. We discuss the potential role of oxygen-independent and oxygen-dependent mechanisms that might contribute to reduced cancer mortality at HA. Reactive oxygen species and their detoxification as well as the hypoxia-inducible factors are especially promising targets and may be related to why cancer mortality is reduced at HA. In addition, we briefly discuss two aspects with a proven impact on tumorigenesis, namely the immune system and tumor surveillance as well as HA-induced metabolic changes. Further animal and clinical studies are clearly needed to explain why cancer mortality is reduced at HA and to decide whether HA or hypoxia-based therapeutic approaches could be implemented for cancer treatment. However, exposure to HA activates multiple adaptive mechanisms (oxygen independent and oxygen dependent) sharing common pathways as well as activating counteracting pathways, which complicate the identification of specific HA-induced mechanisms of tumor suppression.

Hypoxia-mediated translational activation of ITGB3 in breast cancer cells enhances TGF-β signaling and malignant features in vitro and in vivo

Breast cancer is the most prevalent malignancy in women and there is an urgent need for new therapeutic drugs targeting aggressive and metastatic subtypes, such as hormone-refractory triple-negative breast cancer (TNBC). Control of protein synthesis is vital to cell growth and tumour progression and permits increased resistance to therapy and cellular stress. Hypoxic cancer cells attain invasive and metastatic properties and chemotherapy resistance, but the regulation and role of protein synthesis in this setting is poorly understood. We performed a polysomal RNA-Seq screen in non-malignant breast epithelial (MCF10A) and TNBC (MDA-MB-231) cells exposed to normoxic or hypoxic conditions and/or treated with an mTOR pathway inhibitor. Analysis of both the transcriptome and the translatome identified mRNA transcripts translationally activated or repressed by hypoxia in an mTOR-dependent or -independent manner. Integrin beta 3 (ITGB3) was translationally activated in hypoxia and its knockdown increased apoptosis and reduced survival and migration, particularly under hypoxic conditions. Moreover, ITGB3 was required for sustained TGF-β pathway activation and for the induction of Snail and associated epithelial-mesenchymal transition markers. ITGB3 downregulation significantly reduced lung metastasis and improved overall survival in mice. Collectively, these data suggest that ITGB3 is translationally activated in hypoxia and regulates malignant features, including epithelial-mesenchymal transition and cell migration, through the TGF-β pathway, revealing a novel angle for the treatment of therapy-resistant hypoxic tumours.

Mitochondrial ROS control of cancer

Mitochondria serves a primary role in energy maintenance but also function to govern levels of mitochondria-derived reactive oxygen species (mROS). ROS have long been established to play a critical role in tumorigenesis and are now considered to be integral to the regulation of diverse signaling networks that drive proliferation, tumor cell survival and malignant progression. mROS can damage DNA, activate oncogenes, block the function of tumor suppressors and drive migratory signaling. The mitochondrion's oxidant scavenging systems including SOD2, Grx2, GPrx, Trx and TrxR are key of the cellular redox tone. These mitochondrial antioxidant systems serve to tightly control the levels of the primary ROS signaling species, H2O2. The coordinated control of mROS levels is also coupled to the activity of the primary H2O2 consuming enzymes of the mitochondria which are reliant on the epitranscriptomic control of selenocysteine incorporation. This review highlights the interplay between these many oncogenic signaling networks, mROS and the H2O2 emitting and consuming capacity of the mitochondria.

Hypoxia-inducible factor 1 mediates intermittent hypoxia-induced migration of human breast cancer MDA-MB-231 cells

Metastasis is the major cause of triple-negative breast cancer (TNBC)-associated mortality. Hypoxia promotes cancer cell migration and remote metastasis, which occur with hypoxia inducible factor 1α (HIF-1α) stabilization and vimentin upregulation. However, the evolutionary dynamics that link the changes in HIF-1α and vimentin levels under hypoxic conditions are not well understood. In the present study, the effects of intermittent hypoxia (IH), continuous hypoxia (CH) and normoxia on the migration and proliferation of human TNBC MDA-MB-231 cells were investigated. The results demonstrated that IH significantly increased the migration of MDA-MB-231 cells, and this effect was dependent on the number of cycles of hypoxia-reoxygenation. Unexpectedly, IH significantly inhibited cell proliferation, while CH only caused such an effect if hypoxia extended for ≥3 days. IH and CH induced HIF-1α protein accumulation and vimentin upregulation, with a greater effect observed in IH. Knockdown of HIF-1α with siRNA abolished IH-induced cell migration and vimentin upregulation. In summary, multiple cycles of hypoxia and reoxygenation have a more pronounced effect on the promotion of TNBC invasiveness than CH; HIF-1α activation and downstream vimentin upregulation may account for this phenotypic change.

CoCl2 increases the expression of hypoxic markers HIF-1α, VEGF and CXCR4 in breast cancer MCF-7 cells

The aim of the present study was to investigate the effect of a hypoxic environment on the biological behavior of breast cancer MCF-7 cells, using CoCl₂ to mimic the hypoxia model in breast cancer cells. Using 50, 100, 150 and 200 µM CoCl₂ as a hypoxic inducer, a hypoxic model was established in MCF-7 cells in vitro. MTT, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and western blotting assays were performed to detect MCF-7 cell proliferation under hypoxic conditions and the expression of the hypoxic markers hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and C-X-C motif chemokine receptor 4 (CXCR4) mRNA and that of the associated proteins. The RT-qPCR results revealed that there were no obvious changes in the expression of HIF-1α mRNA; however, the expression of CXCR4 and VEGF mRNA increased significantly following treatment with different CoCl₂ concentrations (P<0.05). The results of western blotting identified that CoCl₂ significantly induced the expression of HIF-1α, CXCR4 and VEGF proteins (P<0.05). The MTT assay revealed that different concentrations of CoCl₂ inhibited the proliferation of MCF-7 cells. The TUNEL assay demonstrated that CoCl₂ was able to trigger apoptosis of MCF-7 cells. Therefore, the results of the present study identified that CoCl₂ is able to control MCF-7 cell proliferation and apoptosis, also increasing the expression of HIF-1α, CXCR4 and VEGF. The present study may aid the discovery of a novel method to prevent cell damage and decrease cell proliferation in order to prevent the occurrence and development of breast cancer.

Radiomic analysis in contrast-enhanced CT: predict treatment response to chemoradiotherapy in esophageal carcinoma

Objectives

To investigate the capability of computed-tomography (CT) radiomic features to predict the therapeutic response of Esophageal Carcinoma (EC) to chemoradiotherapy (CRT).

Methods

Pretreatment contrast-enhanced CT images of 49 EC patients (33 responders, 16 nonresponders) who received with CRT were retrospectively analyzed. The region of tumor was contoured by two radiologists. A total of 214 features were extracted from the tumor region. Kruskal-Wallis test and receiver operating characteristic (ROC) analysis were performed to evaluate the capability of each feature on treatment response classification. Support vector machine (SVM) and artificial neural network (ANN) algorithms were used to build models for prediction of the treatment response. The statistical difference between the performances of the models was assessed using McNemar's test.

Results

Radiomic-based classification showed significance in differentiating responders from nonresponders. Five features were found to discriminate nonresponders from responders (AUCs from 0.686 to 0.727). Considering these features, two features (Histogram2D_skewness: P = 0.015. Histogram2D_kurtosis: P = 0.039) were significant for differentiating SDs (stable disease) from PRs (partial response) and one feature (Histogram2D_skewness: P = 0.027) for differentiating SDs from CRs (complete response). Both classifiers showed potential in predicting the treatment response with higher accuracy (ANN: 0.972, SVM: 0.891). No statistically significant difference was observed in the performance of the two classifiers (P = 0.250).

Conclusions

CT-based radiomic features can be used as imaging biomarkers to predict tumor response to CRT in EC patients.

Estrogen receptor β2 induces proliferation and invasiveness of triple negative breast cancer cells: association with regulation of PHD3 and HIF-1α

The two estrogen receptor (ER) subtypes, ERα and ERβ, belong to the nuclear receptor superfamily. The human ERβ variant ERβ2 is proposed to be expressed at higher levels than ERβ1 in many breast tumors and it has been suggested that ERβ2, in contrast to ERβ1, is associated with aggressive phenotypes of various cancers. However, the role of endogenous ERβ2 in breast cancer cells remains elusive. In this study, we identified that triple negative breast cancer (TNBC) cell lines express endogenous ERβ2, but not ERα or ERβ1. This allows novel studies of endogenous ERβ2 functions independent of ERα and ERβ1. We show that overexpression of ERβ2 in TNBC cells increased whereas knockdown of endogenous ERβ2 decreased cell proliferation and cell invasion. To elucidate the molecular mechanism responsible for these cellular phenotypes, we assayed ERβ2 dependent global gene expression profiles. We show that ERβ2 decreases prolyl hydroxylase 3 (PHD3) gene expression and further show that this is associated with increased hypoxia inducible factor 1α (HIF-1α) protein levels, thus providing a possible mechanism for the invasive phenotype. These results are further supported by analysing the expression of ERβ2 and PHD3 in breast tumor samples where a negative correlation between ERβ2 and PHD3 expression was observed. Together, we demonstrate that ERβ2 has an important role in enhancing cell proliferation and invasion, beyond modulation of ERβ and ERβ1 signalling which might contribute to the invasive characteristics of TNBC. The invasive phenotype could potentially be mediated through transcriptional repression of PHD3 and increased HIF-1α protein levels.

Oxygen-dependent regulation of tumor growth and metastasis in human breast cancer xenografts

Background

Tumor hypoxia is relevant for tumor growth, metabolism, resistance to chemotherapy and metastasis. We have previously shown that hyperoxia, using hyperbaric oxygen treatment (HBOT), attenuates tumor growth and shifts the phenotype from mesenchymal to epithelial (MET) in the DMBA-induced mammary tumor model. This study describes the effect of HBOT on tumor growth, angiogenesis, chemotherapy efficacy and metastasis in a triple negative MDA-MB-231 breast cancer model, and evaluates tumor growth using a triple positive BT-474 breast cancer model.

Materials and methods

5 x 10⁵ cancer cells were injected s.c. in the groin area of NOD/SCID female mice. The BT-474 group was supplied with Progesterone and Estradiol pellets 2-days prior to tumor cell injection. Mice were divided into controls (1 bar, pO₂ = 0.2 bar) or HBOT (2.5 bar, pO₂ = 2.5 bar, 90 min, every third day until termination of the experiments). Treatment effects were determined by assessment of tumor growth, proliferation (Ki67-staining), angiogenesis (CD31-staining), metastasis (immunostaining), EMT markers (western blot), stromal components collagen type I, Itgb1 and FSP1 (immunostaining) and chemotherapeutic efficacy (5FU).

Results

HBOT significantly suppressed tumor growth in both the triple positive and negative tumors, and both MDA-MB-231 and BT-474 showed a decrease in proliferation after HBOT. No differences were found in angiogenesis or 5FU efficacy between HBOT and controls. Nevertheless, HBOT significantly reduced both numbers and total area of the metastastatic lesions, as well as reduced expression of N-cadherin, Axl and collagen type I measured in the MDA-MB-231 model. No change in stromal Itgb1 and FSP1 was found in either tumor model.

Conclusion

Despite the fact that behavior and prognosis of the triple positive and negative subtypes of cancer are different, the HBOT had a similar suppressive effect on tumor growth, indicating that they share a common oxygen dependent anti-tumor mechanism. Furthermore, HBOT significantly reduced the number and area of metastatic lesions in the triple negative model as well as a significant reduction in the EMT markers N-cadherin, Axl and density of collagen type I.

A route-based pathway analysis framework integrating mutation information and gene expression data

We propose a new way of analyzing biological pathways in which the analysis combines both transcriptome data and mutation information and uses the outcome to identify "routes" of aberrant pathways potentially responsible for the etiology of disease. Each pathway route is encoded as a Bayesian Network which is initialized with a sequence of conditional probabilities which are designed to encode directionality of regulatory relationships encoded in the pathways, i.e. activation and inhibition relationships. First, we demonstrate the effectiveness of our model through simulation in which the model was able to easily separate Test samples from Control samples using fictitiously perturbed pathway routes. Second, we apply our model to analyze the Breast Cancer data set, available from TCGA, against many cancer pathways available from KEGG and rank the significance of identified pathways. The outcome is consistent with what have already been reported in the literature. Third, survival analysis has been carried out on the same data set by using pathway routes as features. Overall, we envision that our model of using pathway routes for analysis can further refine the conventional ways of subtyping cancer patients as it can discover additional characteristics specific to individual's tumor.

Hypoxia and Inflammation in Cancer, Focus on HIF and NF-κB

Cancer is often characterised by the presence of hypoxia and inflammation. Paramount to the mechanisms controlling cellular responses under such stress stimuli, are the transcription factor families of Hypoxia Inducible Factor (HIF) and Nuclear Factor of κ-light-chain-enhancer of activated B cells (NF-κB). Although, a detailed understating of how these transcription factors respond to their cognate stimulus is well established, it is now appreciated that HIF and NF-κB undergo extensive crosstalk, in particular in pathological situations such as cancer. Here, we focus on the current knowledge on how HIF is activated by inflammation and how NF-κB is modulated by hypoxia. We summarise the evidence for the possible mechanism behind this activation and how HIF and NF-κB function impacts cancer, focusing on colorectal, breast and lung cancer. We discuss possible new points of therapeutic intervention aiming to harness the current understanding of the HIF-NF-κB crosstalk.

Modulating tumor hypoxia by nanomedicine for effective cancer therapy

Hypoxia, a characteristic feature of tumors, is indispensable to tumor angiogenesis, metastasis, and multi drug resistance. Hypoxic avascular regions, deeply embedded inside the tumors significantly hinder delivery of therapeutic agents. The low oxygen tension results in resistance to the current applied anti-cancer therapeutics including radiotherapy, chemotherapy, and photodynamic therapy, the efficacy of which is firmly tied to the level of tumor oxygen supply. However, emerging data indicate that nanocarriers/nanodrugs can offer substantial benefits to improve the efficacy of current therapeutics, through modulation of tumor hypoxia. This review aims to introduce the most recent advances made in nanocarrier mediated targeting of tumor hypoxia. The first part is dedicated to the approaches by which nanocarriers could be designed to target/leverage hypoxia. These approaches include i) inhibiting Hypoxia Inducer Factor (HIF-1α); ii) hypoxia activated prodrugs/linkers; and iii) obligate anaerobe mediated targeting of tumor hypoxia. The second part, details novel nanosystems proposed to modulate tumor hypoxia through tumor oxygenation. These methods seek to lessen tumor hypoxia through vascular normalization, or reoxygenation therapy. The reoxygenation of tumor could be accomplished by: i) generation of oxygen filled nanocarriers; ii) natural/artificial oxygen nanocarriers; and iii) oxygen generators. The efficacy of each approach and their potential in cancer therapy is further discussed.

Reduced cancer mortality at high altitude: The role of glucose, lipids, iron and physical activity

Residency at high altitude (HA) demands adaptation to challenging environmental conditions with hypobaric hypoxia being the most important one. Epidemiological and experimental data suggest that chronic exposure to HA reduces cancer mortality and lowers prevalence of metabolic disorders like diabetes and obesity implying that adaption to HA modifies a broad spectrum of physiological, metabolic and cellular programs with a generally beneficial outcome for humans. However, the complexity of multiple, potentially tumor-suppressive pathways at HA impedes the understanding of mechanisms leading to reduced cancer mortality. Many adaptive processes at HA are tightly interconnected and thus it cannot be ruled out that the entirety or at least some of the HA-related alterations act in concert to reduce cancer mortality. In this review we discuss tumor formation as a concept of competition between healthy and cancer cells with improved fitness - and therefore higher competitiveness - of healthy cells at high altitude. We discuss HA-related changes in glucose, lipid and iron metabolism that may have an impact on tumorigenesis. Additionally, we discuss two parameters with a strong impact on tumorigenesis, namely drug metabolism and physical activity, to underpin their potential contribution to HA-dependent reduced cancer mortality. Future studies are needed to unravel why cancer mortality is reduced at HA and how this knowledge might be used to prevent and to treat cancer patients.

Amplified centrosomes and mitotic index display poor concordance between patient tumors and cultured cancer cells

Centrosome aberrations (CA) and abnormal mitoses are considered beacons of malignancy. Cancer cell doubling times in patient tumors are longer than in cultures, but differences in CA between tumors and cultured cells are uncharacterized. We compare mitoses and CA in patient tumors, xenografts, and tumor cell lines. We find that mitoses are rare in patient tumors compared with xenografts and cell lines. Contrastingly, CA is more extensive in patient tumors and xenografts (~35–50% cells) than cell lines (~5–15%), although CA declines in patient-derived tumor cells over time. Intratumoral hypoxia may explain elevated CA in vivo because exposure of cultured cells to hypoxia or mimicking hypoxia pharmacologically or genetically increases CA, and HIF-1α and hypoxic gene signature expression correlate with CA and centrosomal gene signature expression in breast tumors. These results highlight the importance of utilizing low-passage-number patient-derived cell lines in studying CA to more faithfully recapitulate in vivo cellular phenotypes.

PML promotes metastasis of triple-negative breast cancer through transcriptional regulation of HIF1A target genes

Elucidating the molecular basis of tumor metastasis is pivotal for eradicating cancer-related mortality. Triple-negative breast cancer (TNBC) encompasses a class of aggressive tumors characterized by high rates of recurrence and metastasis, as well as poor overall survival. Here, we find that the promyelocytic leukemia protein PML exerts a prometastatic function in TNBC that can be targeted by arsenic trioxide. We found that, in TNBC patients, constitutive HIF1A activity induces high expression of PML, along with a number of HIF1A target genes that promote metastasis at multiple levels. Intriguingly, PML controls the expression of these genes by binding to their regulatory regions along with HIF1A. This mechanism is specific to TNBC cells and does not occur in other subtypes of breast cancer where PML and prometastatic HIF1A target genes are underexpressed. As a consequence, PML promotes cell migration, invasion, and metastasis in TNBC cell and mouse models. Notably, pharmacological inhibition of PML with arsenic trioxide, a PML-degrading agent used to treat promyelocytic leukemia patients, delays tumor growth, impairs TNBC metastasis, and cooperates with chemotherapy by preventing metastatic dissemination. In conclusion, we report identification of a prometastatic pathway in TNBC and suggest clinical development toward the use of arsenic trioxide for TNBC patients.

Circulating Tumor Cells: Fluid Surrogates of Solid Tumors

Evaluation of circulating tumor cells (CTCs) has demonstrated clinical validity as a prognostic tool based on enumeration, but since the introduction of this tool to the clinic in 2004, further clinical utility and widespread adoption have been limited. However, immense efforts have been undertaken to further the understanding of the mechanisms behind the biology and kinetics of these rare cells, and progress continues toward better applicability in the clinic. This review describes recent advances within the field, with a particular focus on understanding the biological significance of CTCs, and summarizes emerging methods for identifying, isolating, and interrogating the cells that may provide technical advantages allowing for the discovery of more specific clinical applications. Included is an atlas of high-definition images of CTCs from various cancer types, including uncommon CTCs captured only by broadly inclusive nonenrichment techniques.

Thyroid Hormone Controls Breast Cancer Cell Movement via Integrin αV/β3/SRC/FAK/PI3-Kinases

Thyroid hormones (TH) play a fundamental role in diverse processes, including cellular movement. Cell migration requires the integration of events that induce changes in cell structure towards the direction of migration. These actions are driven by actin remodeling and stabilized by the development of adhesion sites to extracellular matrix via transmembrane receptors linked to the actin cytoskeleton. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that promotes cell migration and invasion through the control of focal adhesion turnover. In this work, we demonstrate that the thyroid hormone triiodothyronine (T3) regulates actin remodeling and cell movement in breast cancer T-47D cells through the recruitment of FAK. T3 controls FAK phosphorylation and translocation at sites where focal adhesion complexes are assembled. This process is triggered via rapid signaling to integrin αV/β3, Src, phosphatidylinositol 3-OH kinase (PI3K), and FAK. In addition, we established a cellular model with different concentration of T3 levels: normal, absence, and excess in T-47D breast cancer cells. We found that the expression of Src, FAK, and PI3K remained at normal levels in the excess of T3 model, while it was significantly reduced in the absence model. In conclusion, these results suggest a novel role for T3 as an important modulator of cell migration, providing a starting point for the development of new therapeutic strategies for breast cancer treatment.

Functions and Epigenetic Regulation of Wwox in Bone Metastasis from Breast Carcinoma: Comparison with Primary Tumors

Epigenetic mechanisms influence molecular patterns important for the bone-metastatic process, and here we highlight the role of WW-domain containing oxidoreductase (Wwox). The tumor-suppressor Wwox lacks in almost all cancer types; the variable expression in osteosarcomas is related to lung-metastasis formation, and exogenous Wwox destabilizes HIF-1α (subunit of Hypoxia inducible Factor-1, HIF-1) affecting aerobic glycolysis. Our recent studies show critical functions of Wwox present in 1833-osteotropic clone, in the corresponding xenograft model, and in human bone metastasis from breast carcinoma. In hypoxic-bone metastatic cells, Wwox enhances HIF-1α stabilization, phosphorylation, and nuclear translocation. Consistently, in bone-metastasis specimens Wwox localizes in cytosolic/perinuclear area, while TAZ (transcriptional co-activator with PDZ-binding motif) and HIF-1α co-localize in nuclei, playing specific regulatory mechanisms: TAZ is a co-factor of HIF-1, and Wwox regulates HIF-1 activity by controlling HIF-1α. In vitro, DNA methylation affects Wwox-protein synthesis; hypoxia decreases Wwox-protein level; hepatocyte growth factor (HGF) phosphorylates Wwox driving its nuclear shuttle, and counteracting a Twist program important for the epithelial phenotype and metastasis colonization. In agreement, in 1833-xenograft mice under DNA-methyltransferase blockade with decitabine, Wwox increases in nuclei/cytosol counteracting bone metastasis with prolongation of the survival. However, Wwox seems relevant for the autophagic process which sustains metastasis, enhancing more Beclin-1 than p62 protein levels, and p62 accumulates under decitabine consistent with adaptability of metastasis to therapy. In conclusion, Wwox methylation as a bone-metastasis therapeutic target would depend on autophagy conditions, and epigenetic mechanisms regulating Wwox may influence the phenotype of bone metastasis.

Selective Reversible Inhibition of Autophagy in Hypoxic Breast Cancer Cells Promotes Pulmonary Metastasis

Autophagy influences how cancer cells respond to nutrient deprivation and hypoxic stress, two hallmarks of the tumor microenvironment (TME). In this study, we explored the impact of autophagy on the pathophysiology of breast cancer cells using a novel hypoxia-dependent, reversible dominant-negative strategy to regulate autophagy at the cellular level within the TME. Suppression of autophagy via hypoxia-induced expression of the kinase-dead unc-51-like autophagy-activating kinase (ULK1) mutant K46N increased lung metastases in MDA-MB-231 xenograft mouse models. Consistent with this effect, expressing a dominant-negative mutant of ULK1 or ATG4b or a ULK1-targeting shRNA facilitated cell migration in vitro Functional proteomic and transcriptome analysis revealed that loss of hypoxia-regulated autophagy promotes metastasis via induction of the fibronectin integrin signaling axis. Indeed, loss of ULK1 function increased fibronectin deposition in the hypoxic TME. Together, our results indicated that hypoxia-regulated autophagy suppresses metastasis in breast cancer by preventing tumor fibrosis. These results also suggest cautions in the development of autophagy-based strategies for cancer treatment. Cancer Res; 77(3); 646-57. ©2016 AACR.