Anti-apoptotic role of HIF-1 and AP-1 in paclitaxel exposed breast cancer cells under hypoxia

HIF-1 mediated metabolic reprogramming in cancer: Mechanisms and therapeutic implications

Cancer cells undergo metabolic reprogramming to survive in hypoxic conditions and meet the elevated energy demands of the cancer microenvironment. This metabolic alteration is orchestrated by hypoxia-inducible factor 1 (HIF-1), regulating various processes within cancer cells. The intricate metabolic modifications induced by hypoxia underscore the significance of HIF-1-induced metabolic reprogramming in promoting each aspect of cancer progression. The complex interactions between HIF-1 signalling and cellular metabolic processes in response to hypoxia are examined in this study, focusing on the metabolism of carbohydrates, nucleotides, lipids, and amino acids. Comprehending the various regulatory mechanisms controlled by HIF-1 in cellular metabolism sheds light on the intricate biology of cancer growth and offers useful insights for developing targeted treatments.

Hypoxia-inducible factor in breast cancer: role and target for breast cancer treatment

Globally, breast cancer stands as the most prevalent form of cancer among women. The tumor microenvironment of breast cancer often exhibits hypoxia. Hypoxia-inducible factor 1-alpha, a transcription factor, is found to be overexpressed and activated in breast cancer, playing a pivotal role in the anoxic microenvironment by mediating a series of reactions. Hypoxia-inducible factor 1-alpha is involved in regulating downstream pathways and target genes, which are crucial in hypoxic conditions, including glycolysis, angiogenesis, and metastasis. These processes significantly contribute to breast cancer progression by managing cancer-related activities linked to tumor invasion, metastasis, immune evasion, and drug resistance, resulting in poor prognosis for patients. Consequently, there is a significant interest in Hypoxia-inducible factor 1-alpha as a potential target for cancer therapy. Presently, research on drugs targeting Hypoxia-inducible factor 1-alpha is predominantly in the preclinical phase, highlighting the need for an in-depth understanding of HIF-1α and its regulatory pathway. It is anticipated that the future will see the introduction of effective HIF-1α inhibitors into clinical trials, offering new hope for breast cancer patients. Therefore, this review focuses on the structure and function of HIF-1α, its role in advancing breast cancer, and strategies to combat HIF-1α-dependent drug resistance, underlining its therapeutic potential.

EMP2 Serves as a Functional Biomarker for Chemotherapy-Resistant Triple-Negative Breast Cancer

Breast cancer (BC) remains among the most commonly diagnosed cancers in women worldwide. Triple-negative BC (TNBC) is a subset of BC characterized by aggressive behavior, a high risk of distant recurrence, and poor overall survival rates. Chemotherapy is the backbone for treatment in patients with TNBC, but outcomes remain poor compared to other BC subtypes, in part due to the lack of recognized functional targets. In this study, the expression of the tetraspan protein epithelial membrane protein 2 (EMP2) was explored as a predictor of TNBC response to standard chemotherapy. We demonstrate that EMP2 functions as a prognostic biomarker for patients treated with taxane-based chemotherapy, with high expression at both transcriptomic and protein levels following treatment correlating with poor overall survival. Moreover, we show that targeting EMP2 in combination with docetaxel reduces tumor load in syngeneic and xenograft models of TNBC. These results provide support for the prognostic and therapeutic potential of this tetraspan protein, suggesting that anti-EMP2 therapy may be beneficial for the treatment of select chemotherapy-resistant TNBC tumors.

An uncertainty-based interpretable deep learning framework for predicting breast cancer outcome

BACKGROUND

Predicting outcome of breast cancer is important for selecting appropriate treatments and prolonging the survival periods of patients. Recently, different deep learning-based methods have been carefully designed for cancer outcome prediction. However, the application of these methods is still challenged by interpretability. In this study, we proposed a novel multitask deep neural network called UISNet to predict the outcome of breast cancer. The UISNet is able to interpret the importance of features for the prediction model via an uncertainty-based integrated gradients algorithm. UISNet improved the prediction by introducing prior biological pathway knowledge and utilizing patient heterogeneity information.

RESULTS

The model was tested in seven public datasets of breast cancer, and showed better performance (average C-index = 0.691) than the state-of-the-art methods (average C-index = 0.650, ranged from 0.619 to 0.677). Importantly, the UISNet identified 20 genes as associated with breast cancer, among which 11 have been proven to be associated with breast cancer by previous studies, and others are novel findings of this study.

CONCLUSIONS

Our proposed method is accurate and robust in predicting breast cancer outcomes, and it is an effective way to identify breast cancer-associated genes. The method codes are available at: https://github.com/chh171/UISNet .

Graph Neural Network Model for Prediction of Non-Small Cell Lung Cancer Lymph Node Metastasis Using Protein-Protein Interaction Network and 18F-FDG PET/CT Radiomics

The image texture features obtained from 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) images of non-small cell lung cancer (NSCLC) have revealed tumor heterogeneity. A combination of genomic data and radiomics may improve the prediction of tumor prognosis. This study aimed to predict NSCLC metastasis using a graph neural network (GNN) obtained by combining a protein-protein interaction (PPI) network based on gene expression data and image texture features. 18F-FDG PET/CT images and RNA sequencing data of 93 patients with NSCLC were acquired from The Cancer Imaging Archive. Image texture features were extracted from 18F-FDG PET/CT images and area under the curve receiver operating characteristic curve (AUC) of each image feature was calculated. Weighted gene co-expression network analysis (WGCNA) was used to construct gene modules, followed by functional enrichment analysis and identification of differentially expressed genes. The PPI of each gene module and genes belonging to metastasis-related processes were converted via a graph attention network. Images and genomic features were concatenated. The GNN model using PPI modules from WGCNA and metastasis-related functions combined with image texture features was evaluated quantitatively. Fifty-five image texture features were extracted from 18F-FDG PET/CT, and radiomic features were selected based on AUC (n = 10). Eighty-six gene modules were clustered by WGCNA. Genes (n = 19) enriched in the metastasis-related pathways were filtered using DEG analysis. The accuracy of the PPI network, derived from WGCNA modules and metastasis-related genes, improved from 0.4795 to 0.5830 (p < 2.75 × 10-12). Integrating PPI of four metastasis-related genes with 18F-FDG PET/CT image features in a GNN model elevated its accuracy over a without image feature model to 0.8545 (95% CI = 0.8401-0.8689, p-value < 0.02). This model demonstrated significant enhancement compared to the model using PPI and 18F-FDG PET/CT derived from WGCNA (p-value < 0.02), underscoring the critical role of metastasis-related genes in prediction model. The enhanced predictive capability of the lymph node metastasis prediction GNN model for NSCLC, achieved through the integration of comprehensive image features with genomic data, demonstrates promise for clinical implementation.

ROS production by mitochondria: function or dysfunction?

In eukaryotic cells, ATP generation is generally viewed as the primary function of mitochondria under normoxic conditions. Reactive oxygen species (ROS), in contrast, are regarded as the by-products of respiration, and are widely associated with dysfunction and disease. Important signaling functions have been demonstrated for mitochondrial ROS in recent years. Still, their chemical reactivity and capacity to elicit oxidative damage have reinforced the idea that ROS are the products of dysfunctional mitochondria that accumulate during disease. Several studies support a different model, however, by showing that: (1) limited oxygen availability results in mitochondria prioritizing ROS production over ATP, (2) ROS is an essential adaptive mitochondrial signal triggered by various important stressors, and (3) while mitochondria-independent ATP production can be easily engaged by most cells, there is no known replacement for ROS-driven redox signaling. Based on these observations and other evidence reviewed here, we highlight the role of ROS production as a major mitochondrial function involved in cellular adaptation and stress resistance. As such, we propose a rekindled view of ROS production as a primary mitochondrial function as essential to life as ATP production itself.

Fullerenols Mitigate Radiation-Induced Myocardial Injury

Radiation-induced heart disease is a serious side effect of radiation therapy that can lead to severe consequences. However, effective and safe methods for their prevention and treatment are presently lacking. This study reports the crucial function of fullerenols in protecting cardiomyocytes from radiation injury. First, fullerenols are synthesized using a simple base-catalyzed method. Next, the as-prepared fullerenols are applied as an effective free radical scavenger and broad-spectrum antioxidant to protect against X-ray-induced cardiomyocyte injury. Their ability to reduce apoptosis via the mitochondrial signaling pathway at the cellular level is then verified. Finally, it is observed in animal models that fullerenols accumulate in the heart and alleviate myocardial damage induced by X-rays. This study represents a timely and essential analysis of the prevention and treatment of radiological myocardial injury, providing new insights into the applications of fullerenols for therapeutic strategies.

Laser-activatable oxygen self-supplying nanoplatform for efficiently overcoming colorectal cancer resistance by enhanced ferroptosis and alleviated hypoxic microenvironment

BACKGROUND

Colorectal cancer (CRC) is the second most deadly cancer worldwide, with chemo-resistance remaining a major obstacle in CRC treatment. Notably, the imbalance of redox homeostasis-mediated ferroptosis and the modulation of hypoxic tumor microenvironment are regarded as new entry points for overcoming the chemo-resistance of CRC.

METHODS

Inspired by this, we rationally designed a light-activatable oxygen self-supplying chemo-photothermal nanoplatform by co-assembling cisplatin (CDDP) and linoleic acid (LA)-tailored IR820 via enhanced ferroptosis against colorectal cancer chemo-resistance. In this nanoplatform, CDDP can produce hydrogen peroxide in CRC cells through a series of enzymatic reactions and subsequently release oxygen under laser-triggered photothermal to alleviate hypoxia. Additionally, the introduced LA can add exogenous unsaturated fatty acids into CRC cells, triggering ferroptosis via oxidative stress-related peroxidized lipid accumulation. Meanwhile, photothermal can efficiently boost the rate of enzymatic response and local blood flow, hence increasing the oxygen supply and oxidizing LA for enhanced ferroptosis.

RESULTS

This nanoplatform exhibited excellent anti-tumor efficacy in chemo-resistant cell lines and showed potent inhibitory capability in nude mice xenograft models.

CONCLUSIONS

Taken together, this nanoplatform provides a promising paradigm via enhanced ferroptosis and alleviated hypoxia tumor microenvironment against CRC chemo-resistance.

Structure-Activity Relationship of Truncated 2,8-Disubstituted-Adenosine Derivatives as Dual A2A/A3 Adenosine Receptor Antagonists and Their Cancer Immunotherapeutic Activity

Based on hA2AAR structures, a hydrophobic C8-heteroaromatic ring in 5'-truncated adenosine analogues occupies the subpocket tightly, converting hA2AAR agonists into antagonists while maintaining affinity toward hA3AR. The final compounds of 2,8-disubstituted-N6-substituted 4'-thionucleosides, or 4'-oxo, were synthesized from d-mannose and d-erythrono-1,4-lactone, respectively, using a Pd-catalyst-controlled regioselective cross-coupling reaction. All tested compounds completely antagonized hA2AAR, including 5d with the highest affinity (Ki,A2A = 7.7 ± 0.5 nM). The hA2AAR-5d X-ray structure revealed that C8-heteroaromatic rings prevented receptor activation-associated conformational changes. However, the C8-substituted compounds still antagonized hA3AR. Structural SAR features and docking studies supported different binding modes at A2AAR and A3AR, elucidating pharmacophores for receptor activation and selectivity. Favorable pharmacokinetics were demonstrated, in which 5d displayed high oral absorption, moderate half-life, and bioavailability. Also, 5d significantly improved the antitumor effect of anti-PD-L1 in vivo. Overall, this study suggests that the novel dual A2AAR/A3AR nucleoside antagonists would be promising drug candidates for immune-oncology.

Targeting HIV-1 reservoirs in T cell subsets

The HIV-1 reservoirs harbor the latent proviruses that are integrated into the host genome. It is a challenging task to eradicate the proviruses in order to achieve an HIV cure. We have described a strategy for the clearance of HIV-1 infection through selective elimination of host cells harboring replication-competent HIV (SECH), by inhibition of autophagy and promotion of apoptosis during viral re-activation. HIV-1 can infect various CD4+ T cell subsets, but it is not known whether the SECH approach is equally effective in targeting HIV-1 reservoirs in these different subsets in vivo. In a humanized mouse model, we found that treatments of HIV-1 infection by suppressive antiretroviral therapy (ART) led to the establishment of latent HIV reservoirs in naïve, central memory and effector memory T cells. Moreover, SECH treatments could clear latent HIV-1 reservoirs in these different T cell subsets of humanized mice. Co-culture studies showed that T cell subsets latently infected by HIV-1, but not uninfected bystander cells, were susceptible to cell death induced by SECH treatments. Our study suggests that the SECH strategy is effective for specific targeting of latent HIV-1 reservoirs in different T cell subsets.

Clearance of HIV-1 or SIV reservoirs by promotion of apoptosis and inhibition of autophagy: Targeting intracellular molecules in cure-directed strategies

The reservoirs of the HIV display cellular properties resembling long-lived immune memory cells that could be exploited for viral clearance. Our interest in developing a cure for HIV stems from the studies of immunologic memory against infections. We and others have found that long-lived immune memory cells employ prosurvival autophagy and antiapoptotic mechanisms to protect their longevity. Here, we describe the rationale for the development of an approach to clear HIV-1 by selective elimination of host cells harboring replication-competent HIV (SECH). While reactivation of HIV-1 in the host cells with latency reversing agents (LRAs) induces viral gene expression leading to cell death, LRAs also simultaneously up-regulate prosurvival antiapoptotic molecules and autophagy. Mechanistically, transcription factors that promote HIV-1 LTR-directed gene expression, such as NF-κB, AP-1, and Hif-1α, can also enhance the expression of cellular genes essential for cell survival and metabolic regulation, including Bcl-xL, Mcl-1, and autophagy genes. In the SECH approach, we inhibit the prosurvival antiapoptotic molecules and autophagy induced by LRAs, thereby allowing maximum killing of host cells by the induced HIV-1 proteins. SECH treatments cleared HIV-1 infections in humanized mice in vivo and in HIV-1 patient PBMCs ex vivo. SECH also cleared infections by the SIV in rhesus macaque PBMCs ex vivo. Research efforts are underway to improve the efficacy and safety of SECH and to facilitate the development of SECH as a therapeutic approach for treating people with HIV.

The Role of Hypoxia-Inducible Factor Isoforms in Breast Cancer and Perspectives on Their Inhibition in Therapy

Simple Summary

In many types of cancers, the activity of the hypoxia-inducible factors enhances hallmarks such as suppression of the immune response, altered metabolism, angiogenesis, invasion, metastasis, and more. As a result of observing these features, HIFs became attractive targets in designing anticancer therapy. The lack of effective breast treatment based on HIFs inhibitors and the elusive role of those factors in this type of cancer raises the concern wheter targeting hypoxia-inducible factors is the right path. Results of the study on breast cancer cell lines suggest the need to consider aspects like HIF-1α versus HIF-2α isoforms inhibition, double versus singular isoform inhibition, different hormone receptors status, metastases, and perhaps different not yet investigated issues. In other words, targeting hypoxia-inducible factors in breast cancers should be preceded by a better understanding of their role in this type of cancer. The aim of this paper is to review the role, functions, and perspectives on hypoxia-inducible factors inhibition in breast cancer.

Abstract

Hypoxia is a common feature associated with many types of cancer. The activity of the hypoxia-inducible factors (HIFs), the critical element of response and adaptation to hypoxia, enhances cancer hallmarks such as suppression of the immune response, altered metabolism, angiogenesis, invasion, metastasis, and more. The HIF-1α and HIF-2α isoforms show similar regulation characteristics, although they are active in different types of hypoxia and can show different or even opposite effects. Breast cancers present several unique ways of non-canonical hypoxia-inducible factors activity induction, not limited to the hypoxia itself. This review summarizes different effects of HIFs activation in breast cancer, where areas such as metabolism, evasion of the immune response, cell survival and death, angiogenesis, invasion, metastasis, cancer stem cells, and hormone receptors status have been covered. The differences between HIF-1α and HIF-2α activity and their impacts are given special attention. The paper also discusses perspectives on using hypoxia-inducible factors as targets in anticancer therapy, given current knowledge acquired in molecular studies.

Triple-negative breast cancer drug resistance, durable efficacy, and cure: How advanced biological insights and emerging drug modalities could transform progress

INTRODUCTION

Triple-negative breast cancer (TNBC) is a heterogeneous disease characterized by the lack of estrogen receptor (ER), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2) and often associated with poor survival outcomes. The backbone of current treatments for TNBC relies on chemotherapy; however, resistance to cytotoxic agents is a commonly encountered hurdle to overcome.

AREAS COVERED

: Current understanding on the mechanisms involved in TNBC chemoresistance is evaluated and novel potential actionable targets and recently explored modalities for carrying and delivering chemotherapeutics are highlighted.

EXPERT OPINION

: A comprehensive identification of both genomic and functional TNBC signatures is required for a more definite categorization of the patients in order to prevent insensitivity to chemotherapy and therefore realize the full potential of precision-medicine approaches. In this scenario, cell-line-derived xenografts (CDX), patient-derived xenografts (PDX), patient-derived orthotopic xenografts (PDOX) and patient-derived organoids (PDO) are indispensable experimental models for evaluating the efficacy of drug candidates and predicting the therapeutic response. The combination of increasingly sensitive "omics" technologies, computational algorithms and innovative drug modalities may accelerate the successful translation of novel candidate TNBC targets from basic research to clinical settings, thus contributing to reach optimal clinical output, with lower side effects and reduced resistance.

aWCluster: A Novel Integrative Network-Based Clustering of Multiomics for Subtype Analysis of Cancer Data

The remarkable growth of multi-platform genomic profiles has led to the challenge of multiomics data integration. In this study, we present a novel network-based multiomics clustering founded on the Wasserstein distance from optimal mass transport. This distance has many important geometric properties making it a suitable choice for application in machine learning and clustering. Our proposed method of aggregating multiomics and Wasserstein distance clustering (aWCluster) is applied to breast carcinoma as well as bladder carcinoma, colorectal adenocarcinoma, renal carcinoma, lung non-small cell adenocarcinoma, and endometrial carcinoma from The Cancer Genome Atlas project. Subtypes were characterized by the concordant effect of mRNA expression, DNA copy number alteration, and DNA methylation of genes and their neighbors in the interaction network. aWCluster successfully clusters all cancer types into classes with significantly different survival rates. Also, a gene ontology enrichment analysis of significant genes in the low survival subgroup of breast cancer leads to the well-known phenomenon of tumor hypoxia and the transcription factor ETS1 whose expression is induced by hypoxia. We believe aWCluster has the potential to discover novel subtypes and biomarkers by accentuating the genes that have concordant multiomics measurements in their interaction network, which are challenging to find without the network inference or with single omics analysis.

Myeloid ecotropic viral integration site-1 inhibition promotes apoptosis, suppresses proliferation of acute myeloid leukemia cells, accentuates the effects of anticancer drugs

To investigate the effects of myeloid ecotropic viral integration site-1 (MEIS1) on the proliferation and apoptosis of acute myeloid leukemia (AML) cells and the anticancer effects of the drug, we screened Kasumi-6, KG-1, and Kasumi-1 cells using quantitative reverse transcription polymerase chain reaction. Kasumi-6 and Kasumi-1 cells were subjected to human antigen R (HuR)-mediated interference (IV). Hexokinase 2 (HK2) expression and phosphorylation of protein kinase B (p-AKT) and mammalian target of rapamycin (p-mTOR) were observed with Western blotting. Cell proliferation was assessed using Cell Counting Kit-8, apoptosis was examined using Hoechst 33,258 staining, and glucose uptake was detected with a colorimetric biochemical assay kit. We found that, among the three cell lines tested, MEIS1 expression was highest in Kasumi-1 cells, which were therefore selected for subsequent experiments. Kasumi-1 cells receiving IV showed significantly decreased proliferation (p < 0.05) and increased apoptosis compared to the control group. Compared with the controls, IV significantly increased the expression of HK2, p-AKT, p-mTOR, multidrug resistance-associated protein 1 and P-glycoprotein (P < 0.05), but decreased glucose uptake. Treatment with adriamycin, daunorubicin and imatinib resulted in a progressive increase in inhibition of cell proliferation, with the IV group showing the highest inhibition rate among the three groups (P < 0.05). Thus, inhibition of MEIS1 activity promoted apoptosis, inhibited the proliferation of Kasumi-1 and Kasumi-6 cells, and increaseed the anticancer effect of the drugs, suggesting that inhibition of MEIS1 may be a potential strategy for the treatment of AML.

iTRAQ-based quantitative proteomic analysis of Pelteobagrus vachelli liver in response to hypoxia

Dissolved oxygen is one of the determinants in the healthy farming of Pelteobagrus vachelli. This study, we conducted quantitative proteomics on the juvenile P. vachelli livers using iTRAQ. P. vachelli were treated by 3.75 ± 0.25 mg O₂/L (hypoxia group) and 7.25 ± 0.25 mg O₂/L (control group) for 90 days. The results revealed that under hypoxic conditions, P. vachelli grew slower than control group. Proteomic profiling enabled us to identify 2618 proteins, of which 176 were significantly differentially abundant proteins (DAPs). Verification of protein regulation based on qRT-PCR indicated that the proteomics data were reliable. The top 20 significantly DAPs (10 up-regulated, 10 down-regulated) were primarily involved in energy metabolism, apoptosis inhibition, and heavy metal detoxification. KEGG pathway enrichment analysis revealed significant enrichment of 'protein digestion and absorption', 'glycolysis/gluconeogenesis', and 'phagosome'. Combining the proteomics results of short-term hypoxia (treated with 0.70 ± 0.10 mg O₂ /L for 4 h), we screened 36 common DAPs. The analysis of the 36 common DAPs indicated that P. vachelli responded to the hypoxia by regulating energy supply, inhibiting apoptosis, and disturbing defensive system. Our results lay a theoretical foundation for the cultivation of hypoxia-tolerant species and eco-breeding of P. vachelli. SIGNIFICANCE OF THE STUDY: The hypoxia tolerance of Pelteobagrus vachelli is poor, which will seriously lead to its death in high-density culture. This study analysed the liver proteome of P. vachelli under long-term hypoxia stress (treated for 90 days at 3.75 ± 0.25 mg O₂/L), and then combined the proteome results of short-term hypoxia stress (treated for 4 h at 0.70 ± 0.10 mg O₂/L). The results showed P. vachelli responded to the hypoxia by regulating energy supply, inhibiting apoptosis and disturbing defensive system. The study contributes to the breeding of new hypoxia-tolerant species of P. vachelli and lays the theoretical foundation for eco-breeding.

FV-429 enhances the efficacy of paclitaxel in NSCLC by reprogramming HIF-1α-modulated FattyAcid metabolism

Solid tumors often exhibit hypoxia in their centers, which has been associated with a marked reduction in the sensitivity of the tumor cells to anti-tumor and chemotherapeutic interventions. Here, we found that the occurrence and progress of hypoxic insensitivity to paclitaxel in non-small cell lung cancer (NSCLC) are closely associated with the HIF-1α pathway. The HIF-1α protein upregulated the expression of adipose differentiation-related protein (ADRP), fatty acid synthase (FASN), and sterol regulatory element binding protein 1(SREBP1), while simultaneously downregulating carnitine palmitoyltransferase 1 (CPT1), thereby leading to a more pronounced uptake of lipids and reduced oxidation of fatty acids. Diminished levels of fatty acids led to reduced Wnt pathway activation and β-catenin nuclear translocation, leading to G2/M cell cycle arrest. In this study, FV-429, a derivative of the natural flavonoid wogonin, reprogrammed metabolism of cancer cells and decreased fatty acid levels. Moreover, paclitaxel-induced G2/M phase arrest in hypoxia-resistant NSCLC was hampered but FV-429 improved the sensitivity of these cancer cells to paclitaxel. FV-429 activated and modulated fatty acid metabolism in NSCLC cells, significantly reduced levels of fatty acids within cells and increased the oxidation of these fatty acids. The results of our study demonstrated that FV-429 could reshape fatty acid metabolism in hypoxia-induced paclitaxel-resistant NSCLC and enhance the sensitivity of NSCLC cells to paclitaxel through G2/M phase arrest deterioration, by inactivating the Wnt pathway, and suggested the possibility of using FV-429 as a promising candidate therapeutic agent for advanced NSCLC.

Post-Hypoxic Cells Promote Metastatic Recurrence after Chemotherapy Treatment in TNBC

Simple Summary

Intratumoral hypoxia is a negative prognostic factor in breast cancer progression and recurrence. By implementing a hypoxia fate-mapping system, we followed cells that experience intratumoral hypoxia in vivo and determined that these cells have an increased ability to metastasize compared to cells that were never exposed to hypoxia. In this work, we investigate whether cells that experienced intratumoral hypoxia are also resistant to chemotherapy. By utilizing both in vivo and ex vivo models, we conclude that metastatic cells found in the lung and liver, that were exposed to hypoxia in the primary tumor, are less sensitive to doxorubicin and paclitaxel and drive recurrence after treatment. Our studies also suggest that chemoresistance is associated with a cancer stem cell-like phenotype that is maintained in post-hypoxic cells.

Abstract

Hypoxia occurs in 90% of solid tumors and is associated with treatment failure, relapse, and mortality. HIF-1α signaling promotes resistance to chemotherapy in cancer cell lines and murine models via multiple mechanisms including the enrichment of breast cancer stem cells (BCSCs). In this work, we utilize a hypoxia fate-mapping system to determine whether triple-negative breast cancer (TNBC) cells that experience hypoxia in the primary tumor are resistant to chemotherapy at sites of metastasis. Using two orthotopic mouse models of TNBC, we demonstrate that cells that experience intratumoral hypoxia and metastasize to the lung and liver have decreased sensitivity to doxorubicin and paclitaxel but not cisplatin or 5-FU. Resistance to therapy leads to metastatic recurrence caused by post-hypoxic cells. We further determined that the post-hypoxic cells that metastasize are enriched in pathways related to cancer stem cell gene expression. Overall, our results show that even when hypoxic cancer cells are reoxygenated in the bloodstream they retain a hypoxia-induced cancer stem cell-like phenotype that persists and promotes resistance and eventually recurrence.

HIF-Dependent Mechanisms of Relationship between Hypoxia Tolerance and Tumor Development

Oxygen deficiency is one of the key pathogenetic factors determining development and severity of many diseases, including inflammatory, infectious diseases, and cancer. Lack of oxygen activates the signaling pathway of the hypoxia-inducible transcription factor HIF in cells that has three isoforms, HIF-1, HIF-2, HIF-3, regulating expression of several thousand genes. Throughout tumor progression, HIF activation stimulates angiogenesis, promotes changes in cell metabolism, adhesion, invasiveness, and ability to metastasize. HIF isoforms can play opposite roles in the development of inflammatory and neoplastic processes. Humans and laboratory animals differ both in tolerance to hypoxia and in the levels of expression of HIF and HIF-dependent genes, which may lead to predisposition to the development of certain oncological disorders. In particular, the ratio of different histogenetic types of tumors may vary among people living in the mountains and at the sea level. However, despite the key role of hypoxia at almost all stages of tumor development, basal tolerance to oxygen deficiency is not considered as a factor of predisposition to the tumor growth initiation. In literature, there are many works characterizing the level of local hypoxia in various tumors, and suggesting fundamental approaches to its mitigation by HIF inhibition. HIF inhibitors, as a rule, have a systemic effect on the organism, however, basal tolerance of an organism to hypoxia as well as the level of HIF expression are not taken into account in the process of their use. The review summarizes the literature data on different HIF isoforms and their role in tumor progression, with extrapolation to organisms with high and low tolerance to hypoxia, as well as on the prevalence of various types of tumors in the populations living at high altitudes.

The Hypoxia-Long Noncoding RNA Interaction in Solid Cancers

Hypoxia is one of the representative microenvironment features in cancer and is considered to be associated with the dismal prognosis of patients. Hypoxia-driven cellular pathways are largely regulated by hypoxia-inducible factors (HIFs) and notably exert influence on the hallmarks of cancer, such as stemness, angiogenesis, invasion, metastasis, and the resistance towards apoptotic cell death and therapeutic resistance; therefore, hypoxia has been considered as a potential hurdle for cancer therapy. Growing evidence has demonstrated that long noncoding RNAs (lncRNAs) are dysregulated in cancer and take part in gene regulatory networks owing to their various modes of action through interacting with proteins and microRNAs. In this review, we focus attention on the relationship between hypoxia/HIFs and lncRNAs, in company with the possibility of lncRNAs as candidate molecules for controlling cancer.

Insights into Temperature and Hypoxia Tolerance in Cowpea Weevil via HIF-1

Cowpea weevil (Callosobruchus maculatus) is a major pest that leads to severe damage of the stored leguminous grains. Several management approaches, including physical barriers, biological or chemical methods, are used for controlling bruchid in cowpea. These methods usually target the metabolically active state of weevil. However, it becomes less effective at early stages as egg, larva, or pupa under low temperature and oxygen conditions. Since hypoxia-inducible factor-1 (HIF-1) is known to coordinate multiple gene responses to low oxygen or low temperature signals, we examined the HIF-1α gene expression under low temperature and hypoxic treatments. At −20 °C, it took 4 h to reduce the survival rate for eggs, larvae, and pupae down to 10%, while at 4 °C and 15 °C, the survival rate remained higher than 50% even after 128 h as HIF-1α gene expression peaked at 15 °C. Moreover, HIF-1 protein offers a valuable target for early stage pest control complementary to traditional methods. In particular, HIF-1 inhibitor camptothecin (CPT), one of the five HIF-1 inhibitors examined, achieved a very significant reduction of 96.2% and 95.5% relative to the control in weevil survival rate into adult at 4 °C and 30 °C, respectively. Our study can be used as one model system for drug development in virus infections and human cancer.

Hypoxia and Extracellular Acidification as Drivers of Melanoma Progression and Drug Resistance

Hypoxia and elevated extracellular acidification are prevalent features of solid tumors and they are often shown to facilitate cancer progression and drug resistance. In this review, we have compiled recent and most relevant research pertaining to the role of hypoxia and acidification in melanoma growth, invasiveness, and response to therapy. Melanoma represents a highly aggressive and heterogeneous type of skin cancer. Currently employed treatments, including BRAF V600E inhibitors and immune therapy, often are not effective due to a rapidly developing drug resistance. A variety of intracellular mechanisms impeding the treatment were discovered. However, the tumor microenvironment encompassing stromal and immune cells, extracellular matrix, and physicochemical conditions such as oxygen level or acidity, may also influence the therapy effectiveness. Hypoxia and acidification are able to reprogram the metabolism of melanoma cells, enhance their survival and invasiveness, as well as promote the immunosuppressive environment. For this reason, these physicochemical features of the melanoma niche and signaling pathways related to them emerge as potential therapeutic targets.

Association of TYRP1 with hypoxia and its correlation with patient outcome in uveal melanoma

PURPOSE

Molecular mechanisms of uveal melanoma development in association with high pigmentation are unclear. Tyrosinase Related Protein (TYRP1) is not only one of the important melanogenesis marker that contributes to melanin synthesis, but can also prevents the melanocyte death. The induction of melanogenesis leads to induction of HIF-1α which can affect the behavior of melanoma cells and its surrounding environment. The aim of our study was to determine the expression of TYRP1 and HIF-1α at the protein and RNA level and determine its prognostic significance.

METHODS

In the present study, the expression of TYRP1 and HIF-1α was investigated on 61 formalin-fixed paraffin-embedded choroidal melanoma samples by immunohistochemistry. Fresh 50 samples were validated by real-time PCR. Results were correlated with clinicopathological parameters and Kaplan-Meier was performed to determine the prognostic significance.

RESULTS

High immunoexpression of TYRP1 and HIF-1α was present in 61 and 54% of patients, respectively. Both TYRP1 and HIF-1α correlated well with high pigmentation and BAP1 (BRCA1 Associated Protein-1) loss (p < 0.05) at IHC level as well as transcriptional level. There was reduced metastatic free survival in patients with necrosis and this was statistically significant (p = 0.010).

CONCLUSION

Our findings indicate that TYRP1 can be used as a potential biomarker in the development of targeted therapy in UM. Further studies on melanogenesis markers associated with TYRP1 could provide us a better understanding in this field.

Hypoxia in Breast Cancer-Scientific Translation to Therapeutic and Diagnostic Clinical Applications

Breast cancer has been the leading cause of female cancer deaths for decades. Intratumoral hypoxia, mainly caused by structural and functional abnormalities in microvasculature, is often associated with a more aggressive phenotype, increased risk of metastasis and resistance to anti-malignancy treatments. The response of cancer cells to hypoxia is ascribed to hypoxia-inducible factors (HIFs) that activate the transcription of a large battery of genes encoding proteins promoting primary tumor vascularization and growth, stromal cell recruitment, extracellular matrix remodeling, cell motility, local tissue invasion, metastasis, and maintenance of the cancer stem cell properties. In this review, we summarized the role of hypoxia specifically in breast cancer, discuss the prognostic and predictive value of hypoxia factors, potential links of hypoxia and endocrine resistance, cancer hypoxia measurements, further involved mechanisms, clinical application of hypoxia-related treatments and open questions.

Hypoxia-mediated drug resistance in breast cancers

Tissue hypoxia in solid tumors is caused by several pathological changes associated with tumor growth, including altered microvasculature structure, increased diffusional distances, and tumor-associated anemia. As the oxygen tension decreases, tumor cells adapt to the limited oxygen supply. Previous studies have shown that such adaptation leads to an aggressive phenotype that is resistant to many anti-cancer therapies. Induction of hypoxia inducible factors (HIFs) mediates many proteomic and genomic changes associated with tumor hypoxia. In breast cancers, HIFs not only predict poor prognosis, but also promote metastasis and drug resistance. Several studies have proposed HIF-1α as a druggable target in drug-resistant breast cancers, leading to the synthesis and development of small molecule inhibitors. Disappointingly, however, none of these small molecule inhibitors have progressed to clinical use. In this review, we briefly discuss the role of HIF-1α in breast cancer drug resistance and summarize the current and future approaches to targeting this transcription factor in breast cancer treatment.

Mechanisms of Taxane Resistance

The taxane family of chemotherapy drugs has been used to treat a variety of mostly epithelial-derived tumors and remain the first-line treatment for some cancers. Despite the improved survival time and reduction of tumor size observed in some patients, many have no response to the drugs or develop resistance over time. Taxane resistance is multi-faceted and involves multiple pathways in proliferation, apoptosis, metabolism, and the transport of foreign substances. In this review, we dive deeper into hypothesized resistance mechanisms from research during the last decade, with a focus on the cancer types that use taxanes as first-line treatment but frequently develop resistance to them. Furthermore, we will discuss current clinical inhibitors and those yet to be approved that target key pathways or proteins and aim to reverse resistance in combination with taxanes or individually. Lastly, we will highlight taxane response biomarkers, specific genes with monitored expression and correlated with response to taxanes, mentioning those currently being used and those that should be adopted. The future directions of taxanes involve more personalized approaches to treatment by tailoring drug-inhibitor combinations or alternatives depending on levels of resistance biomarkers. We hope that this review will identify gaps in knowledge surrounding taxane resistance that future research or clinical trials can overcome.

Nanomedicine and chemotherapeutics drug delivery: challenges and opportunities

Cancer is considered as one of the biggest threats to humans worldwide. Researchers suggest that tumour is not just a single mass, it comprises cancerous cells surrounded by noncancerous cells such as immune cells, adipocytes and cancer stem cells (CSCs) in the extracellular matrix (ECM) containing distinct components such as proteins, glycoproteins and enzymes; thus tumour microenvironment (TME) is partially complex. Multiple interactions happen in the dynamic microenvironment (ME) lead to an acidic, hypoxic and stiff ME that is considered as one of the major contributors to cancer progression and metastasis. Furthermore, TME involves in drug resistance mechanisms and affects enhanced permeability and retention (EPR) in tumours. In such a scenario, the first step to accomplish satisfying results is the identification and recognition of this ME. Then designing proper drug delivery systems can perform selectively towards cancerous cells. In this way, several targeting and stimuli/enzyme responsive drug delivery systems have been designed. More importantly, it is necessary to design a drug delivery system that can penetrate deeper into the tumours, efficiently and selectively. Various drug delivery systems such as exosomes and size-switchable nanocarriers (NCs) could decrease side effects and increase tumour treatment results by selective accumulation in tumours. In this review, TME features, current drug delivery approaches, challenges and promising strategies towards cancer treatment are discussed.

PERK-Mediated Suppression of microRNAs by Sildenafil Improves Mitochondrial Dysfunction in Heart Failure

Oxidative/nitrosative stress is a major trigger of cardiac dysfunction, involving the unfolded protein response and mitochondrial dysfunction. Activation of nitric oxide-cyclic guanosine monophosphate-protein kinase G signaling by sildenafil improves cardiac mal-remodeling during pressure-overload-induced heart failure. Transcriptome analysis was conducted in failing hearts with or without sildenafil treatment. Protein kinase R-like endoplasmic reticulum (ER) kinase (PERK) downstream signaling pathways, EIF2 and NRF2, were significantly altered. Although EIF2 signaling was suppressed, NRF2 signaling was upregulated, inhibiting the maturation of miR 24-3p through EGFR-mediated Ago2 phosphorylation. To study the effect of sildenafil on these pathways, we generated cardiac-specific PERK knockout mice. In these mice, sildenafil could not inhibit the maturations, the nuclear translocation of NRF2 was suppressed, and mitochondrial dysfunction advanced. Altogether, these results show that PERK-mediated suppression of miRNAs by sildenafil is vital for maintaining mitochondrial homeostasis through NRF2-mediated oxidative stress response.

Microfluidic platform for three-dimensional cell culture under spatiotemporal heterogeneity of oxygen tension

Cells in a tumor microenvironment are exposed to spatial and temporal variations in oxygen tension due to hyperproliferation and immature vascularization. Such spatiotemporal oxygen heterogeneity affects the behavior of cancer cells, leading to cancer growth and metastasis, and thus, it is essential to clarify the cellular responses of cancer cells to oxygen tension. Herein, we describe a new double-layer microfluidic device allowing the control of oxygen tension and the behavior of cancer cells under spatiotemporal oxygen heterogeneity. Two parallel gas channels were located above the media and gel channels to enhance gas exchange, and a gas-impermeable polycarbonate film was embedded in the device to prevent the diffusion of atmospheric oxygen. Variations in oxygen tension in the device with the experimental parameters and design variables were investigated computationally and validated by using oxygen-sensitive nanoparticles. The present device can generate a uniform hypoxic condition at oxygen levels down to 0.3% O2, as well as a linear oxygen gradient from 3% O2 to 17% O2 across the gel channel within 15 min. Moreover, human breast cancer cells suspended in type I collagen gel were introduced in the gel channel to observe their response under controlled oxygen tension. Hypoxic exposure activated the proliferation and motility of the cells, which showed a local maximum increase at 5% O2. Under the oxygen gradient condition, the increase in the cell number was relatively high in the central mild hypoxia region. These findings demonstrate the utility of the present device to study cellular responses in an oxygen-controlled microenvironment.

H2S inhalation-induced energy metabolism disturbance is involved in LPS mediated hepatocyte apoptosis through mitochondrial pathway

Hydrogen sulfide (H₂S) is a toxic gas and one of the air pollutants of great concern. High-concentrated H₂S can induce energy metabolism disturbance and apoptosis. However, the mechanism of H₂S-induced liver injuries is unknown. Lipopolysaccharide (LPS), the main component of endotoxin, can cause fulminant hepatitis. Here, we evaluated the effects of H₂S combined with LPS on the energy metabolism and apoptosis pathway in the liver using a one-day-old chicken as a model. Our results showed that the expression levels of energy metabolism-related genes (AMP-activated protein kinase (AMPK), Hypoxia-inducible factor-1 (HIF-1), aconitase 2 (ACO2), hexokinase1 (HK1), hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), lactate dehydrogenase B (LDHB), phosphofructokinase (PFK), pyruvate kinase (PK) and succinate dehydrogenase B (SDHB)) tended to decrease, that the status of apoptosis increased, and that the expression levels of apoptosis-related genes (caspase3, BCL2, and bax) increased in H₂S group, suggesting that H₂S exposure disturbed the energy metabolism in the liver and induced hepatocyte apoptosis through the mitochondrial pathway. In addition, H₂S combined with the LPS aggravated the level of energy metabolism disorders and apoptosis, indicating that H₂S inhalation-induced energy metabolism disturbance is involved in LPS-mediated hepatocyte apoptosis through the mitochondrial pathway.

TMEM Proteins in Cancer: A Review

A transmembrane protein (TMEM) is a type of protein that spans biological membranes. Many of them extend through the lipid bilayer of the plasma membrane but others are located to the membrane of organelles. The TMEM family gathers proteins of mostly unknown functions. Many studies showed that TMEM expression can be down- or up-regulated in tumor tissues compared to adjacent healthy tissues. Indeed, some TMEMs such as TMEM48 or TMEM97 are defined as potential prognostic biomarkers for lung cancer. Furthermore, experimental evidence suggests that TMEM proteins can be described as tumor suppressors or oncogenes. TMEMs, such as TMEM45A and TMEM205, have also been implicated in tumor progression and invasion but also in chemoresistance. Thus, a better characterization of these proteins could help to better understand their implication in cancer and to allow the development of improved therapy strategies in the future. This review gives an overview of the implication of TMEM proteins in cancer.

Hypoxia and Noncoding RNAs in Taxane Resistance

Taxanes are chemotherapeutic drugs employed in the clinic to treat a variety of malignancies. Despite their overall efficacy, cancer cells often display resistance to taxanes. Therefore, new strategies to increase the effectiveness of taxane-based chemotherapeutics are urgently needed. Multiple molecular players are linked to taxane resistance; these include efflux pumps, DNA repair mechanisms, and hypoxia-related pathways. In addition, emerging evidence indicates that both non-coding RNAs and epigenetic effectors might also be implicated in taxane resistance. Here we focus on the causes of taxane resistance, with the aim to envisage an integrated model of the 'taxane resistance phenome'. This model could help the development of novel therapeutic strategies to treat taxane-resistant neoplasms.

HIF1-alpha expressing cells induce a hypoxic-like response in neighbouring cancer cells

Background

Hypoxia stimulates metastasis in cancer and is linked to poor patient prognosis. In tumours, oxygen levels vary and hypoxic regions exist within a generally well-oxygenated tumour. However, whilst the heterogeneous environment is known to contribute to metastatic progression, little is known about the mechanism by which heterogeneic hypoxia contributes to cancer progression. This is largely because existing experimental models do not recapitulate the heterogeneous nature of hypoxia.

The primary effector of the hypoxic response is the transcription factor Hypoxia inducible factor 1-alpha (HIF1-alpha). HIF1-alpha is stabilised in response to low oxygen levels in the cellular environment and its expression is seen in hypoxic regions throughout the tumour.

Methods

We have developed a model system in which HIF1-alpha can be induced within a sub-population of cancer cells, thus enabling us to mimic the effects of heterogeneic HIF1-alpha expression.

Results

We show that induction of HIF1-alpha not only recapitulates elements of the hypoxic response in the induced cells but also results in significant changes in proliferation, gene expression and mammosphere formation within the HIF1-alpha negative population.

Conclusions

These findings suggest that the HIF1-alpha expressing cells found within hypoxic regions are likely to contribute to the subsequent progression of a tumour by modifying the behaviour of cells in the non-hypoxic regions of the local micro-environment.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4577-1) contains supplementary material, which is available to authorized users.

Integrin-Linked Kinase Silencing Induces a S/G2/M Phases Cell Cycle slowing and Modulates Metastasis-Related Genes in SGC7901 Humancc Gastric Carcinoma Cells

Background and aim

Integrin-linked kinase has been implicated in metastasis of human tumors. Recent studies have also shown that the down-regulation of integrin-linked kinase has anti-tumor potential by inhibiting the metastatic potential of several types of cultured human cancer cells. However, the mechanism by which integrin-linked kinase regulates metastasis in human gastric carcinoma is not fully clear. We investigated the effect of integrin-linked kinase deletion on metastasis-associated markers in human gastric carcinoma SGC-7901 cell lines.

Methods

We generated cell lines depleted for integrin-linked kinase. Cell adhesion and invasion were measured by the MTS assay and transwell assay. The cell cycle was measured by flow cytometry. Expression of metastasis-related genes was assessed by reporter assay, quantitative RT-PCR and western blotting.

Results

Our data showed an inhibitory effect on cell adhesion and invasion after silencing of integrin-linked kinase. The cell cycle was slowed in S/G2/M phases. Metastasis-related genes E-cadherin, MMP-2/9 and cystatin B, as well as the signaling molecules p-Akt, NF-κB, and AP-1 activation, were also modulated. Our results indicate that integrin-linked kinase plays an important role in metastasis of human gastric carcinoma cells.

Conclusions

Down-regulation of integrin-linked kinase resulted in the impairment of the metastatic potential of gastric tumor cells by regulating metastasis-related gene expression, by inhibiting the Akt pathway as well as the activity of transcription factors. Integrin-linked kinase could be used as a potential therapeutic target.

Interleukin-6 contributes to chemoresistance in MDA-MB-231 cells via targeting HIF-1α

Chemoresistance is a critical challenge in the clinical treatment of triple-negative breast cancer (TNBC). It has been well documented that inflammatory mediators from tumor microenvironment are involved in the pathogenesis of TNBC and might be related to chemoresistance of cancer cells. In this study, the contribution of interleukin-6 (IL-6), one of the principal oncogenic molecules, in chemoresistance of a TNBC cell line MDA-MB-231 was first investigated. The results showed that IL-6 treatment could induce upregulation of HIF-1α via the activation of STAT3 in MDA-MB-231 cells, which consequently contributed to its effect against chemotherapeutic drug-induced cytotoxicity and cell apoptosis. However, knockdown of HIF-1α attenuated such effect via affecting the expressions of apoptosis-related molecules as Bax and Bcl-2 and drug transporters as P-gp and MRP1. This study indicated that targeting at IL-6/HIF-1α signaling pathway might be an effective strategy to overcome chemoresistance in TNBC therapy.

Cobalt chloride compromises transepithelial barrier properties of CaCo-2 BBe human gastrointestinal epithelial cell layers

Background

Elevation of the transcription factor HIF-1 is a prominent mediator of not only processes that accompany hypoxia, but also the tumor microenvironment and tissue regeneration. This study uses mediators of “chemical hypoxia” to ask the question whether HIF-1α elevation in a healthy epithelial cell layer leads to leakiness in its tight junctional seals.

Methods

Transepithelial electrical resistance and transepithelial diffusion of ¹⁴C–D-mannitol and other radiolabeled probes are used as indicators of transepithelial barrier function of CaCo-2 BBe human gastrointestinal epithelial cell layers cultured on permeable supports. Western immunoblot analyses of integral tight junctional proteins (occludin and claudins) are used as further indicators of barrier function change.

Results

Cobalt, an inhibitor of the prolyl hydroxylase enzymes governing HIF-1α breakdown in the cell, induces transepithelial leakiness in CaCo-2 BBe cell layers in a time and concentration-dependent manner. This increased leakiness is accompanied by significant changes in certain specific integral tight junctional (TJ) proteins such as a decreased level of occludin and increased level of claudin-5. Similar results regarding barrier function compromise also occur with other chemical inhibitors of HIF-1α breakdown, namely ciclopiroxolamine (CPX) and dimethyloxalylglycine (DMOG). The increased leak is manifested by both decreased transepithelial electrical resistance (R_t) and increased paracellular diffusion of D-mannitol (J_m). The induced transepithelial leak shows significant size selectivity, consistent with induced effects on TJ permeability. Less-differentiated cell layers were significantly more affected than well-differentiated cell layers regarding induced transepithelial leak. A genetically modified CaCo-2 variant with reduced levels of HIF-1β, showed reduced transepithelial leak in response to cobalt exposure, further indicating that elevation of HIF-1α levels induced by agents of “chemical hypoxia” is responsible for the compromised barrier function of the CaCo-2 BBe cell layers.

Conclusions

Exposure to inducers of chemical hypoxia elevated HIF-1α levels and increased transepithelial leak. The degree of epithelial differentiation has significant effects on this action, possibly explaining the varying effects of HIF-1 modulation in epithelial and endothelial barrier function in different physiological and pathophysiological conditions.

Electronic supplementary material

The online version of this article (doi: 10.1186/s12876-017-0731-5) contains supplementary material, which is available to authorized users.

Tumor control by hypoxia-specific chemotargeting of iron-oxide nanoparticle - Berberine complexes in a mouse model

AIM

To evaluate the therapeutic efficacy of hypoxic cell-sensitizer Sanazole (SAN) -directed targeting of cytotoxic drug Berberine (BBN) and Iron-oxide nanoparticle (NP) complexes, to solid tumor in Swiss albino mice.

MAIN METHODS

NP-BBN-SAN complexes were characterized by FTIR, XRD, TEM and Nano-size analyzer. This complex was orally administered to mice-bearing solid tumor in hind limb. Tumor regression was analysed by measuring tumor volume. Cellular DNA damages were assessed by comet assay. Transcriptional expression of genes related to tumor hypoxia and apoptosis was evaluated by quantitative real-time PCR and morphological changes in tissues were analysed by histopathology. Also levels of antioxidants and tumor markers in tissues and serum biochemical parameters were analysed.

KEY FINDINGS

Administration of NP-BBN-SAN complexes reduced tumor volume and studies were focussed on the underlying mechanisms. Extensive damage to cellular-DNA; down-regulated transcription of hif-1α, vegf, akt and bcl2; and up-regulated expression of bax and caspases, were observed in tumor. Results on tumor markers, antioxidant-status and serum parameters corroborated the molecular findings. Histopathology of tumor, liver and kidney revealed the therapeutic specificity of NP-BBN-SAN.

SIGNIFICANCE

Thus SAN and NP can be used for specific targeting of drugs, to hypoxic solid tumor, to improve therapeutic efficacy.

Chemotherapy-Induced Ca2+ Release Stimulates Breast Cancer Stem Cell Enrichment

Breast cancer stem cells (BCSCs) play a critical role in tumor recurrence and metastasis. Exposure of breast cancer cells to chemotherapy leads to an enrichment of BCSCs. Here, we find that chemotherapy induces the expression of glutathione S-transferase omega 1 (GSTO1), which is dependent on hypoxia-inducible factor 1 (HIF-1) and HIF-2. Knockdown of GSTO1 expression abrogates carboplatin-induced BCSC enrichment, decreases tumor initiation and metastatic capacity, and delays tumor recurrence after chemotherapy. GSTO1 interacts with the ryanodine receptor RYR1 and promotes calcium release from the endoplasmic reticulum. Increased cytosolic calcium levels activate PYK2 → SRC → STAT3 signaling, leading to increased expression of pluripotency factors and BCSC enrichment. HIF inhibition blocks chemotherapy-induced GSTO1 expression and BCSC enrichment. Combining HIF inhibitors with chemotherapy may improve clinical outcome in breast cancer.

Molecular cloning, characterization and expression analysis of (B-cell lymphoma-2) Bcl-2 in the orange-spotted grouper (Epinephelus coioides)

Bcl-2 is a pro-survival member of Bcl-2 like superfamily, playing an important role in regulating the apoptotic process. In this study, the full-length Bcl-2 (EcBcl-2) was obtained, consisting of a 5'UTR of 290 bp, an ORF of 699 bp and a 3'UTR of 920 bp. EcBcl-2 gene encoded a polypeptide of 232 amino acids with an estimated molecular mass of 26.12 KDa and a predicted isoelectric point (pI) of 6.93. The deduced amino acid sequence analysis showed that EcBcl-2 consisted of the conserved residues and characteristic domains known to the critical functionality for Bcl-2. qRT-PCR analysis revealed that EcBcl-2 transcript was expressed in all the examined tissues, while the strongest expression level was observed in liver, followed by the expression in blood, gill, kidney, spleen, heart, intestine and muscle. The groupers challenged with V. alginolyticus showed a significant increase of EcBcl-2 mRNA in immune tissues. In addition, western blotting analysis confirmed that the up-regulation of EcBcl-2 protein expression was detected in liver. Subcellular localization analysis revealed that EcBcl-2 was localized in both nucleus and cytoplasm. Overexpression of EcBcl-2 can inhibit the LPS-induced apoptosis and activate the transcription activity of NF-κB and AP-1, while the deletion of BH1, BH2, BH3 or BH4 domain from EcBcl-2 can impede the signaling transduction. These results indicate that EcBcl-2 may play a regulatory role in the apoptotic process.

STAT3 but Not HIF-1α Is Important in Mediating Hypoxia-Induced Chemoresistance in MDA-MB-231, a Triple Negative Breast Cancer Cell Line

Hypoxia-induced chemoresistance (HICR) is a well-recognized phenomenon, and in many experimental models, hypoxia inducible factor-1α (HIF-1α) is believed to be a key player. We aimed to better understand the mechanism underlying HICR in a triple negative breast cancer cell line, MDA-MB-231, with a focus on the role of HIF-1α. In this context, the effect of hypoxia on the sensitivity of MDA-MB-231 cells to cisplatin and their stem-like features was evaluated and the role of HIF-1α in both phenomena was assessed. Our results showed that hypoxia significantly increased MDA-MB-231 resistance to cisplatin. Correlating with this, intracellular uptake of cisplatin was significantly reduced under hypoxia. Furthermore, the stem-like features of MDA-MB-231 cells increased as evidenced by the significant increases in the expression of ATP-binding cassette (ABC) drug transporters, the proportion of CD44⁺/CD24⁻ cells, clonogenic survival and cisplatin chemoresistance. Under hypoxia, both the protein level and DNA binding of HIF-1α was dramatically increased. Surprisingly, siRNA knockdown of HIF-1α did not result in an appreciable change to HICR. Instead, signal transducer and activator of transcription 3 (STAT3) activation was found to be important. STAT3 activation may confer HICR by upregulating ABC transporters, particularly ABCC2 and ABCC6. This study has demonstrated that, in MDA-MB-231 cells, STAT3 rather than HIF-1α is important in mediating HICR to cisplatin.

Contextual Refinement of Regulatory Targets Reveals Effects on Breast Cancer Prognosis of the Regulome

Gene expression regulators, such as transcription factors (TFs) and microRNAs (miRNAs), have varying regulatory targets based on the tissue and physiological state (context) within which they are expressed. While the emergence of regulator-characterizing experiments has inferred the target genes of many regulators across many contexts, methods for transferring regulator target genes across contexts are lacking. Further, regulator target gene lists frequently are not curated or have permissive inclusion criteria, impairing their use. Here, we present a method called iterative Contextual Transcriptional Activity Inference of Regulators (icTAIR) to resolve these issues. icTAIR takes a regulator’s previously-identified target gene list and combines it with gene expression data from a context, quantifying that regulator’s activity for that context. It then calculates the correlation between each listed target gene’s expression and the quantitative score of regulatory activity, removes the uncorrelated genes from the list, and iterates the process until it derives a stable list of refined target genes. To validate and demonstrate icTAIR’s power, we use it to refine the MSigDB c3 database of TF, miRNA and unclassified motif target gene lists for breast cancer. We then use its output for survival analysis with clinicopathological multivariable adjustment in 7 independent breast cancer datasets covering 3,430 patients. We uncover many novel prognostic regulators that were obscured prior to refinement, in particular NFY, and offer a detailed look at the composition and relationships among the breast cancer prognostic regulome. We anticipate icTAIR will be of general use in contextually refining regulator target genes for discoveries across many contexts. The icTAIR algorithm can be downloaded from https://github.com/icTAIR.

Gene expression regulators, such as transcription factors and microRNAs, are critical actors in cellular physiology and pathophysiology and act by modulating the expression levels of sets of target genes. Given their significance, numerous experiments have sought to characterize the specific target genes of specific regulators, which in turn has led to regulator target gene list databases. Unfortunately, these lists are plagued by poor curation and validation. Further, all lists suffer from the fundamental issue that regulator targets vary across tissue type and physiological state, or “context”, making them poor for conducting downstream, context-specific analyses. To address this issue, here we present a method called icTAIR that contextually-refines regulator target gene lists. To demonstrate its value, we use icTAIR to take the largest-available database of regulator target gene lists, refine it for the breast cancer context, and use both the pre-refined and refined lists for downstream survival analyses in over 3,400 tumors. We find that icTAIR improves the statistical power of the analyses by multiple orders of magnitude. This in turn lets us map the relational network of breast cancer regulators and identify regulators with prognostic effects even after clinicopathological adjustment. We anticipate icTAIR will be broadly useful in regulator studies.

Molecular cloning and characterization of PTEN in the orange-spotted grouper (Epinephelus coioides)

PTEN is a key tumor suppressor gene that can play a regulatory role in the cellular proliferation, survival and apoptosis. In this study, the full-length PTEN (EcPTEN) was obtained, containing a 5'UTR of 745 bp, an ORF of 1269 bp and a 3'UTR of 106 bp. The EcPTEN gene encoded a polypeptide of 422 amino acids with an estimated molecular mass of 49.14 KDa and a predicted isoelectric point (pI) of 6.34. The deduced amino acid sequence analysis showed that EcPTEN comprised the conserved residues and the characteristic domains known to the critical functionality of PTEN. qRT-PCR analysis revealed that EcPTEN mRNA was broadly expressed in all the examined tissues, while the highest expression level was observed in liver, followed by the expression in blood, kidney, spleen, heart, gill, muscle and intestine. The groupers challenged with Vibrio alginolyticus showed a sharp increase of EcPTEN mRNA expression in immune tissues. In addition, western blotting analysis confirmed that the up-regulation of EcPTEN protein expression was steadily induced in liver. Subcellular localization analysis indicated that EcPTEN was localized in both nucleus and cytoplasm. Overexpression of EcPTEN can activate the apoptotic cascade and abrogate NF-kB, AP-1, Stat3 and Myc promoter activity in Hela cells. These results indicated that EcPTEN harboring highly-conserved domains with a close sequence similarity to those of PTP superfamily may disrupt the mammalian signalings and play a regulatory role in the apoptotic process.

Jaceosidin induces apoptosis through Bax activation and down-regulation of Mcl-1 and c-FLIP expression in human renal carcinoma Caki cells

Jaceosidin is a flavonoid isolated from Artemisia vestita that has been reported to possess anti-tumor and anti-proliferative activities in many cancer cells. In this study, we investigated the anti-tumor activity of jaceosodin in renal carcinoma cells. Jaceosidin induced apoptosis in multiple human renal carcinoma cells (Caki, ACHN, A498, and 786-O), lung cancer cells (A549) and glioma cells (U251MG). In contrast, jaceosidin does not induce apoptosis in normal human umbilical vein cells (EA.hy926). Apoptotic cell death was associated with the activation of caspase-3 and cleavage of poly (ADP-ribose) polymerase. Treatment with jaceosidin also caused loss of mitochondrial membrane potential (MMP) and Bax activation, which led to the release of cytochrome c into the cytosol. We also found that jaceosidin downregulated Mcl-1 and c-FLIP expression at the transcriptional level and that ectopic expression of Mcl-1 and c-FLIP blocked jaceosidin-induced apoptosis. Cumulatively, our results suggest that jaceosidin induces apoptosis in renal carcinoma cells through Bax activation and reduces Mcl-1 and c-FLIP expression.

Crosstalk between E2f1 and c-Myc mediates hepato-protective effect of royal jelly on taxol-induced damages

Previous histopathological studies have shown the hepatotoxicity of paclitaxel (TXL). However, there is little known about the molecular pathway(s) of TXL-induced hepatotoxicity. Therefore, this study aimed to uncover the role of two transcription factors in the TXL-induced hepatotoxicity. Moreover, the hepato-protective effect of royal jelly (RJ) on TXL-induced toxicity was investigated. Wistar rats were divided into control and test groups. The test groups along with TXL received various doses of RJ (0, 50, 100 and 150 mg/kg, body weight). Biochemical hepatic functional assays, histopathological studies and hepatic superoxide dismutase level were determined. Additionally, the expression of E2f1 and cellular-myelocytomatosis (c-Myc) at messenger RNA (mRNA) level in the liver was evaluated. The hepatic functional biomarkers showed a significant ( p < 0.05) elevation in the TXL-received animals, while RJ administration for 28 days resulted in a remarkable reduction in TXL-elevated alkaline phosphatase, alanine transaminase and lactate dehydrogenase levels. The TXL-treated animals showed a significant ( p < 0.05) up-regulation of E2f1 and down-regulation of c-Myc at mRNA level, respectively. RJ lowered the expression of E2f1 while enhanced the expression of c-Myc in a dose-dependent manner. Our data suggest the hepato-protective effects of RJ on TXL-induced toxicity, which may attribute to a clear crosstalk between E2f1 and c-Myc as two regulators of liver growth.

Docetaxel induced-JNK2/PHD1 signaling pathway increases degradation of HIF-1α and causes cancer cell death under hypoxia

HIF-1 (hypoxia-inducible factor-1) regulates the expression of more than 70 genes involved in angiogenesis, tumor growth, metastasis, chemoresistance, and radioresistance. Thus, there is growing interest in using HIF-1 inhibitors as anticancer drugs. Docetaxel, a Food and Drug Administration-approved anticancer drug, is reported to enhance HIF-1α degradation. Here, we investigated the molecular mechanism underlying docetaxel-induced HIF-1α degradation and cancer cell death under hypoxic conditions. Docetaxel pretreatment enhanced the polyubiquitination and proteasome-mediated degradation of HIF-1α, and increased cancer cell death under hypoxic conditions. Docetaxel also activated the prolyl hydroxylase, PHD1, in hypoxia, and pharmacological inhibition or siRNA-mediated knockdown of PHD1 prevented docetaxel-induced HIF-1α degradation and cancer cell death. Additionally, siRNA-mediated JNK2 knockdown blocked docetaxel-induced HIF-1α degradation and cancer cell death by inhibiting PHD1 activation. A luciferase reporter assay revealed that inhibition of the JNK2/PHD1 signaling pathway significantly increased the transcriptional activity of HIF-1 in docetaxel-treated cancer cells under hypoxia. Consistent with these results, docetaxel-treated JNK2-knockdown tumors grew much faster than control tumors through inhibition of docetaxel-induced PHD1 activation and degradation of HIF-1α. Our results collectively show that, under hypoxic conditions, docetaxel induces apoptotic cell death through JNK2/PHD1 signaling-mediated HIF-1α degradation.

Effects of melatonin on HIF-1α and VEGF expression and on the invasive properties of hepatocarcinoma cells

Liver cancer is the sixth most commonly occurring cancer globally, and the main histological type is hepatocellular carcinoma. This type of neoplasia has a poor prognosis due to a high rate of recurrence and intrahepatic metastasis, which are closely are closely associated with the angiogenic process. Vascular endothelial growth factor (VEGF), which is under the control of hypoxia inducible factor-1α (HIF-1α), stimulates the proliferation of endothelial cells and increases cell permeability, promoting the growth, spread and metastasis of tumors. Melatonin, the main hormone secreted by the pineal gland, may have a significant role in tumor suppression and has demonstrated antiangiogenic and antimetastatic effects. The aim of the present study was to analyze the cell viability, migration and invasion, as well as the expression of proangiogenic proteins VEGF and HIF-1α, in HepG2 hepatocarcinoma cells, following treatment with melatonin. Cells were cultured and cell viability was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression of proangiogenic proteins VEGF and HIF-1α, under conditions of normoxia and hypoxia, was verified using immunocytochemistry and quantified by densitometry. The analysis of the processes of cell migration and invasion was performed in a Boyden chamber. The MTT assay revealed a reduction in cell viability (P=0.018) following treatment with 1 mM melatonin for 24 h. The expression of proangiogenic proteins VEGF and HIF-1α was reduced in cells treated with 1 mM melatonin for 24 h in normoxic (P<0.001) and hypoxic (P<0.001) conditions, compared with the control group and with induced hypoxia alone. The rate of cell migration and invasion was additionally reduced in cells treated with 1 mM melatonin for 48 h when compared with the control group (P=0.496). The results of the present study suggest that melatonin may have an antiproliferative, antiangiogenic and antimetastatic role in hepatocarcinoma cells and may present a novel therapeutic option for the treatment of liver cancer.

Hypoxia Induces Autophagy through Translational Up-Regulation of Lysosomal Proteins in Human Colon Cancer Cells

Hypoxia occurs in a wide variety of physiological and pathological conditions, including tumorigenesis. Tumor cells have to adapt to hypoxia by altering their gene expression and protein synthesis. Here, we showed that hypoxia inhibits translation through activation of PERK and inactivation of mTOR in human colon cancer HCT116 cells. Prolonged hypoxia (1% O₂, 16 h) dramatically inhibits general translation in HCT116 cells, yet selected mRNAs remain efficiently translated under such a condition. Using microarray analysis of polysome- associated mRNAs, we identified a large number of hypoxia-regulated genes at the translational level. Efficiently translated mRNAs during hypoxia were validated by polysome profiling and quantitative real-time RT-PCR. Pathway enrichment analysis showed that many of the up-regulated genes are involved in lysosome, glycan and lipid metabolism, antigen presentation, cell adhesion, and remodeling of the extracellular matrix and cytoskeleton. The majority of down-regulated genes are involved in apoptosis, ubiquitin-mediated proteolysis, and oxidative phosphorylation. Further investigation showed that hypoxia induces lysosomal autophagy and mitochondrial dysfunction through translational regulation in HCT116 cells. The abundance of several translation factors and the mTOR kinase activity are involved in hypoxia-induced mitochondrial autophagy in HCT116 cells. Our studies highlight the importance of translational regulation for tumor cell adaptation to hypoxia.

Lead Phytochemicals for Anticancer Drug Development

Cancer is a serious concern at present. A large number of patients die each year due to cancer illnesses in spite of several interventions available. Development of an effective and side effects lacking anticancer therapy is the trending research direction in healthcare pharmacy. Chemical entities present in plants proved to be very potential in this regard. Bioactive phytochemicals are preferential as they pretend differentially on cancer cells only, without altering normal cells. Carcinogenesis is a complex process and includes multiple signaling events. Phytochemicals are pleiotropic in their function and target these events in multiple manners; hence they are most suitable candidate for anticancer drug development. Efforts are in progress to develop lead candidates from phytochemicals those can block or retard the growth of cancer without any side effect. Several phytochemicals manifest anticancer function in vitro and in vivo. This article deals with these lead phytomolecules with their action mechanisms on nuclear and cellular factors involved in carcinogenesis. Additionally, druggability parameters and clinical development of anticancer phytomolecules have also been discussed.