Hypoxia-inducible factor-1 modulates gene expression in solid tumors and influences both angiogenesis and tumor growth

Targeting hypoxia-inducible factor 1 (HIF-1) signaling with natural products toward cancer chemotherapy

Tumor cells are often exposed to hypoxia because of the lower oxygen supply deep inside the tumor tissues. However, tumor cells survive in these severe conditions by adapting to hypoxic stress through the induction of hypoxia-inducible factor 1 (HIF-1) signaling. HIF-1 activation is responsible for the expression of numerous HIF-1 target genes, which are related to cell survival, proliferation, angiogenesis, invasion, metastasis, cancer stemness, and metabolic reprogramming. Therefore, HIF-1 is expected to be a potential pharmacological target for cancer therapy. Small molecules derived from natural products (microbial origin, plant-derived, or marine organisms) have been shown to have unique chemical structures and biological activities, including HIF-1 inhibition. Several studies identified HIF-1 inhibitors from natural products. In this review, we summarize the current HIF-1 signaling inhibitors originating from natural products with a variety of modes of action, mainly focusing on microbial metabolites.

miR-519d-3p suppresses tumorigenicity and metastasis by inhibiting Bcl-w and HIF-1α in NSCLC

Bcl-w, a member of the Bcl-2 family, is highly expressed in various solid tumor, including lung cancer, suggesting that it is involved in cancer cell survival and carcinogenesis. Solid cancer-induced hypoxia has been reported to increase angiogenesis, growth factor, gene instability, invasion, and metastasis. Despite many studies on the treatment of non-small cell lung cancer (NSCLC) with a high incidence rate, the survival rate of patients has not improved because the cancer cells acquired resistance to treatment. This study investigated the correlation between Bcl-w expression and hypoxia in tumor malignancy of NSCLC. Meanwhile, microRNAs (miRNAs) are involved in a variety of key signaling mechanisms associated with hypoxia. Therefore, we discovered miR-519d-3p, which inhibits the expression of Bcl-w and hypoxia-inducing factor (HIF)-1α, and found that it reduces hypoxia-induced tumorigenesis. Spearman's correlation analysis showed that the expression levels of miR-519d-3p and Bcl-w/HIF-1α were negatively correlated, respectively. This showed that miR-519d-3p can be used as a diagnostic biomarker and target therapy for NSCLC.

Angiogenesis induction in breast cancer: A paracrine paradigm

Breast cancer is the most prevalent type of cancer among women globally. Angiogenesis contributes significantly to breast cancer progression and dissemination. Neovascularization is concurrent with the progression and growth of breast cancer. Breast cancer cells control angiogenesis by secreting pro-angiogenic factors like fibroblast growth factor, vascular endothelial growth factor, interleukin, transforming growth factor-β, platelet-derived growth factor and several others. These pro-angiogenic factors trigger neovascularization, and thereby lead to breast cancer development and metastasis. The hypoxia-inducible factor (HIF)-regulated angiogenesis cascade is a crucial underlying factor in breast cancer growth and metastasis. To that end, several efforts have been made to identify druggable targets within the HIF-angiogenesis components. However, escape pathways are a major hindrance for targeted therapies against angiogenesis. Thus, understanding the key factors that trigger breast cancer angiogenesis is critical in elucidating ways to inhibit breast cancer. The current review provides an overview of the key growth factors that trigger breast cancer angiogenesis.

HIF-1-Independent Mechanisms Regulating Metabolic Adaptation in Hypoxic Cancer Cells

In solid tumours, cancer cells exist within hypoxic microenvironments, and their metabolic adaptation to this hypoxia is driven by HIF-1 transcription factor, which is overexpressed in a broad range of human cancers. HIF inhibitors are under pre-clinical investigation and clinical trials, but there is evidence that hypoxic cancer cells can adapt metabolically to HIF-1 inhibition, which would provide a potential route for drug resistance. Here, we review accumulating evidence of such adaptions in carbohydrate and creatine metabolism and other HIF-1-independent mechanisms that might allow cancers to survive hypoxia despite anti-HIF-1 therapy. These include pathways in glucose, glutamine, and lipid metabolism; epigenetic mechanisms; post-translational protein modifications; spatial reorganization of enzymes; signalling pathways such as Myc, PI3K-Akt, 2-hyxdroxyglutarate and AMP-activated protein kinase (AMPK); and activation of the HIF-2 pathway. All of these should be investigated in future work on hypoxia bypass mechanisms in anti-HIF-1 cancer therapy. In principle, agents targeted toward HIF-1β rather than HIF-1α might be advantageous, as both HIF-1 and HIF-2 require HIF-1β for activation. However, HIF-1β is also the aryl hydrocarbon nuclear transporter (ARNT), which has functions in many tissues, so off-target effects should be expected. In general, cancer therapy by HIF inhibition will need careful attention to potential resistance mechanisms.

Loss-of-Function Genetic Screening Identifies Aldolase A as an Essential Driver for Liver Cancer Cell Growth Under Hypoxia

BACKGROUND AND AIMS

Hypoxia is a common feature of the tumor microenvironment (TME), which promotes tumor progression, metastasis, and therapeutic drug resistance through a myriad of cell activities in tumor and stroma cells. While targeting hypoxic TME is emerging as a promising strategy for treating solid tumors, preclinical development of this approach is lacking in the study of HCC.

APPROACH AND RESULTS

From a genome-wide CRISPR/CRISPR-associated 9 gene knockout screening, we identified aldolase A (ALDOA), a key enzyme in glycolysis and gluconeogenesis, as an essential driver for HCC cell growth under hypoxia. Knockdown of ALDOA in HCC cells leads to lactate depletion and consequently inhibits tumor growth. Supplementation with lactate partly rescues the inhibitory effects mediated by ALDOA knockdown. Upon hypoxia, ALDOA is induced by hypoxia-inducible factor-1α and fat mass and obesity-associated protein-mediated N⁶ -methyladenosine modification through transcriptional and posttranscriptional regulation, respectively. Analysis of The Cancer Genome Atlas shows that elevated levels of ALDOA are significantly correlated with poor prognosis of patients with HCC. In a screen of Food and Drug Administration-approved drugs based on structured hierarchical virtual platforms, we identified the sulfamonomethoxine derivative compound 5 (cpd-5) as a potential inhibitor to target ALDOA, evidenced by the antitumor activity of cpd-5 in preclinical patient-derived xenograft models of HCC.

CONCLUSIONS

Our work identifies ALDOA as an essential driver for HCC cell growth under hypoxia, and we demonstrate that inhibition of ALDOA in the hypoxic TME is a promising therapeutic strategy for treating HCC.

Endothelial Cell PHD2-HIF1α-PFKFB3 Contributes to Right Ventricle Vascular Adaptation in Pulmonary Hypertension

BACKGROUND

Humans and animals with pulmonary hypertension (PH) show right ventricular (RV) capillary growth, which positively correlates with overall RV hypertrophy. However, molecular drivers of RV vascular augmentation in PH are unknown. Prolyl hydroxylase (PHD2) is a regulator of hypoxia-inducible factors (HIFs), which transcriptionally activates several proangiogenic genes, including the glycolytic enzyme PFKFB3. We hypothesized that a signaling axis of PHD2-HIF1α-PFKFB3 contributes to adaptive coupling between the RV vasculature and tissue volume to maintain appropriate vascular density in PH.

METHODS AND RESULTS

We used design-based stereology to analyze endothelial cell (EC) proliferation and the absolute length of the vascular network in the RV free wall, relative to the tissue volume in mice challenged with hypoxic PH. We observed increased RV EC proliferation starting after 6 hours of hypoxia challenge. Using parabiotic mice, we found no evidence for a contribution of circulating EC precursors to the RV vascular network. Mice with transgenic deletion or pharmacologic inhibition of PHD2, HIF1α, or PFKFB3 all had evidence of impaired RV vascular adaptation following hypoxia PH challenge.

CONCLUSIONS

PHD2-HIF1α-PFKFB3 contributes to structural coupling between the RV vascular length and tissue volume in hypoxic mice, consistent with homeostatic mechanisms which maintain appropriate vascular density. Activating this pathway could help augment the RV vasculature and preserve RV substrate delivery in PH, as an approach to promote RV function.

Hypoxia stimulates the migration and invasion of osteosarcoma via up-regulating the NUSAP1 expression

Osteosarcoma is a highly aggressive malignant tumor, which most commonly occurs in children and adolescents. This study aims to reveal that hypoxia promotes the invasion of osteosarcoma cells by up-regulating the expression of NUSAP1. The expression of HIF-1α and NUSAP1 was significantly up-regulated in MG63 cells cultured in hypoxia for 6–36 h. Furthermore, hypoxia induced the migration and invasion of MG63 cells and regulated the level of E-cad, N-cad, Vimentin, Snail, Slug, MMP2, and MMP9 proteins. Importantly, knockdown of NUSAP1 inhibited hypoxia-induced cell migration and invasion. In the hypoxia microenvironment, the addition of HIF-1α inhibitor or the transfection of siRNA specifically targeting HIF-1α significantly reduced the expression of HIF-1α and NUSAP1 and markedly inhibited the migration and invasion of MG63 cells under the hypoxia microenvironment. In conclusion, hypoxia induced the expression of NUSAP1 in a HIF-1α-dependent manner, stimulating the migration and invasion of MG63 cells.

Angiogenic activities are increased via upregulation of HIF-1α expression in gefitinib-resistant non-small cell lung carcinoma cells

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) have been used to treat patients with non-small cell lung cancer (NSCLC) and activating EGFR mutations; however, the emergence of secondary mutations in EGFR or the acquisition of resistance to EGFR-TKIs can develop and is involved in clinical failure. Since angiogenesis is associated with tumor progression and the blockade of antitumor drugs, inhibition of angiogenesis could be a rational strategy for developing anticancer drugs combined with EGFR-TKIs to treat patients with NSCLC. The signaling pathway mediated by hypoxia-inducible factor-1 (HIF-1) is essential for tumor angiogenesis. The present study aimed to identify the dependence of gefitinib resistance on HIF-1α activity using angiogenesis assays, western blot analysis, colony formation assay, xenograft tumor mouse model and immunohistochemical analysis of tumor tissues. In the NSCLC cell lines, HIF-1α protein expression levels and hypoxia-induced angiogenic activities were found to be increased. In a xenograft mouse tumor model, tumor tissues derived from gefitinib-resistant PC9 cells showed increased protein expression of HIF-1α and angiogenesis within the tumors. Furthermore, inhibition of HIF-1α suppressed resistance to gefitinib, whereas overexpression of HIF-1α increased resistance to gefitinib. The results from the present study provides evidence that HIF-1α was associated with the acquisition of resistance to gefitinib and suggested that inhibiting HIF-1α alleviated gefitinib resistance in NSCLC cell lines.

The HIF complex recruits the histone methyltransferase SET1B to activate specific hypoxia-inducible genes

Hypoxia-inducible transcription factors (HIFs) are fundamental to cellular adaptation to low oxygen levels, but it is unclear how they interact with chromatin and activate their target genes. Here, we use genome-wide mutagenesis to identify genes involved in HIF transcriptional activity, and define a requirement for the histone H3 lysine 4 (H3K4) methyltransferase SET1B. SET1B loss leads to a selective reduction in transcriptional activation of HIF target genes, resulting in impaired cell growth, angiogenesis and tumor establishment in SET1B-deficient xenografts. Mechanistically, we show that SET1B accumulates on chromatin in hypoxia, and is recruited to HIF target genes by the HIF complex. The selective induction of H3K4 trimethylation at HIF target loci is both HIF- and SET1B-dependent and, when impaired, correlates with decreased promoter acetylation and gene expression. Together, these findings show SET1B as a determinant of site-specific histone methylation and provide insight into how HIF target genes are differentially regulated.

Up-down regulation of HIF-1α in cancer progression

Hypoxia induicible factor-1 alpha (HIF-1α) is a key transcription factor in cancer progression and target therapy in cancer. HIF-1α acts differently depending on presence or absence of Oxygen. In an oxygen-immersed environment, HIF-1α completely deactivated and destroyed by the ubiquitin proteasome pathway (UPP). In contrast, in the oxygen-free environment, it escapes destruction and enters to the nucleus of cells then upregulates many genes involved in cancer progression. Overexpressed HIF-1α and downstream genes support cancer progression through various mechanisms including angiogenesis, proliferation and survival of cells, metabolism reprogramming, invasion and metastasis, cancer stem cell maintenance, induction of genetic instability, and treatment resistance. HIF-1α can be provoked by signaling pathways unrelated to hypoxia during cancer progression. Therefore, cancer development and progression can be modulated by targeting HIF-1α and its downstream signaling molecules. In this regard, HIF-1α inhibitors which are categorized into the agents that regulate HIF-1α in gene, mRNA and protein levels used as an efficient way in cancer treatment. Also, HIF-1α expression can be negatively affected by the agents suppressing the activation of mTOR, PI3k/Akt and MAPK pathways.

Architecture of Cancer-Associated Fibroblasts in Tumor Microenvironment: Mapping Their Origins, Heterogeneity, and Role in Cancer Therapy Resistance

The tumor stroma, a key component of the tumor microenvironment (TME), is a key determinant of response and resistance to cancer treatment. The stromal cells, extracellular matrix (ECM), and blood vessels influence cancer cell response to therapy and play key roles in tumor relapse and therapeutic outcomes. Of the stromal cells present in the TME, much attention has been given to cancer-associated fibroblasts (CAFs) as they are the most abundant and important in cancer initiation, progression, and therapy resistance. Besides releasing several factors, CAFs also synthesize the ECM, a key component of the tumor stroma. In this expert review, we examine the role of CAFs in the regulation of tumor cell behavior and reveal how CAF-derived factors and signaling influence tumor cell heterogeneity and development of novel strategies to combat cancer. Importantly, CAFs display both phenotypic and functional heterogeneity, with significant ramifications on CAF-directed therapies. Principal anti-cancer therapies targeting CAFs take the form of: (1) CAFs' ablation through use of immunotherapies, (2) re-education of CAFs to normalize the cells, (3) cellular therapies involving CAFs delivering drugs such as oncolytic adenoviruses, and (4) stromal depletion via targeting the ECM and its related signaling. The CAFs' heterogeneity could be a result of different cellular origins and the cancer-specific tumor microenvironmental effects, underscoring the need for further multiomics and biochemical studies on CAFs and the subsets. Lastly, we present recent advances in therapeutic targeting of CAFs and the success of such endeavors or their lack thereof. We recommend that to advance global public health and personalized medicine, treatments in the oncology clinic should be combinatorial in nature, strategically targeting both cancer cells and stromal cells, and their interactions.

Mitochondrial oxidative metabolism contributes to a cancer stem cell phenotype in cholangiocarcinoma

BACKGROUND & AIMS

Little is known about the metabolic regulation of cancer stem cells (CSCs) in cholangiocarcinoma (CCA). We analyzed whether mitochondrial-dependent metabolism and related signaling pathways contribute to stemness in CCA.

METHODS

The stem-like subset was enriched by sphere culture (SPH) in human intrahepatic CCA cells (HUCCT1 and CCLP1) and compared to cells cultured in monolayer. Extracellular flux analysis was examined by Seahorse technology and high-resolution respirometry. In patients with CCA, expression of factors related to mitochondrial metabolism was analyzed for possible correlation with clinical parameters.

RESULTS

Metabolic analyses revealed a more efficient respiratory phenotype in CCA-SPH than in monolayers, due to mitochondrial oxidative phosphorylation. CCA-SPH showed high mitochondrial membrane potential and elevated mitochondrial mass, and over-expressed peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α, a master regulator of mitochondrial biogenesis. Targeting mitochondrial complex I in CCA-SPH using metformin, or PGC-1α silencing or pharmacologic inhibition (SR-18292), impaired spherogenicity and expression of markers related to the CSC phenotype, pluripotency, and epithelial-mesenchymal transition. In mice with tumor xenografts generated by injection of CCA-SPH, administration of metformin or SR-18292 significantly reduced tumor growth and determined a phenotype more similar to tumors originated from cells grown in monolayer. In patients with CCA, expression of PGC-1α correlated with expression of mitochondrial complex II and of stem-like genes. Patients with higher PGC-1α expression by immunostaining had lower overall and progression-free survival, increased angioinvasion and faster recurrence. In GSEA analysis, patients with CCA and high levels of mitochondrial complex II had shorter overall survival and time to recurrence.

CONCLUSIONS

The CCA stem-subset has a more efficient respiratory phenotype and depends on mitochondrial oxidative metabolism and PGC-1α to maintain CSC features.

LAY SUMMARY

The growth of many cancers is sustained by a specific type of cells with more embryonic characteristics, termed 'cancer stem cells'. These cells have been described in cholangiocarcinoma, a type of liver cancer with poor prognosis and limited therapeutic approaches. We demonstrate that cancer stem cells in cholangiocarcinoma have different metabolic features, and use mitochondria, an organelle located within the cells, as the major source of energy. We also identify PGC-1α, a molecule which regulates the biology of mitochondria, as a possible new target to be explored for developing new treatments for cholangiocarcinoma.

Glucose Metabolic Dysfunction in Neurodegenerative Diseases-New Mechanistic Insights and the Potential of Hypoxia as a Prospective Therapy Targeting Metabolic Reprogramming

Glucose is the main circulating energy substrate for the adult brain. Owing to the high energy demand of nerve cells, glucose is actively oxidized to produce ATP and has a synergistic effect with mitochondria in metabolic pathways. The dysfunction of glucose metabolism inevitably disturbs the normal functioning of neurons, which is widely observed in neurodegenerative disease. Understanding the mechanisms of metabolic adaptation during disease progression has become a major focus of research, and interventions in these processes may relieve the neurons from degenerative stress. In this review, we highlight evidence of mitochondrial dysfunction, decreased glucose uptake, and diminished glucose metabolism in different neurodegeneration models such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD). We also discuss how hypoxia, a metabolic reprogramming strategy linked to glucose metabolism in tumor cells and normal brain cells, and summarize the evidence for hypoxia as a putative therapy for general neurodegenerative disease.

Clear cell renal cell carcinoma ontogeny and mechanisms of lethality

The molecular features that define clear cell renal cell carcinoma (ccRCC) initiation and progression are being increasingly defined. The TRACERx Renal studies and others that have described the interaction between tumour genomics and remodelling of the tumour microenvironment provide important new insights into the molecular drivers underlying ccRCC ontogeny and progression. Our understanding of common genomic and chromosomal copy number abnormalities in ccRCC, including chromosome 3p loss, provides a mechanistic framework with which to organize these abnormalities into those that drive tumour initiation events, those that drive tumour progression and those that confer lethality. Truncal mutations in ccRCC, including those in VHL, SET2, PBRM1 and BAP1, may engender genomic instability and promote defects in DNA repair pathways. The molecular features that arise from these defects enable categorization of ccRCC into clinically and therapeutically relevant subtypes. Consideration of the interaction of these subtypes with the tumour microenvironment reveals that specific mutations seem to modulate immune cell populations in ccRCC tumours. These findings present opportunities for disease prevention, early detection, prognostication and treatment.

The Role of 2-Oxoglutarate Dependent Dioxygenases in Gliomas and Glioblastomas: A Review of Epigenetic Reprogramming and Hypoxic Response

Gliomas are a heterogeneous group of cancers that predominantly arise from glial cells in the brain, but may also arise from neural stem cells, encompassing low-grade glioma and high-grade glioblastoma. Whereas better diagnosis and new treatments have improved patient survival for many cancers, glioblastomas remain challenging with a highly unfavorable prognosis. This review discusses a super-family of enzymes, the 2-oxoglutarate dependent dioxygenase enzymes (2-OGDD) that control numerous processes including epigenetic modifications and oxygen sensing, and considers their many roles in the pathology of gliomas. We specifically describe in more detail the DNA and histone demethylases, and the hypoxia-inducible factor hydroxylases in the context of glioma, and discuss the substrate and cofactor requirements of the 2-OGDD enzymes. Better understanding of how these enzymes contribute to gliomas could lead to the development of new treatment strategies.

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.

Exploiting the acquired vulnerability of cisplatin-resistant tumors with a hypoxia-amplifying DNA repair-inhibiting (HYDRI) nanomedicine

Various cancers treated with cisplatin almost invariably develop drug resistance that is frequently caused by substantial DNA repair. We searched for acquired vulnerabilities of cisplatin-resistant cancers to identify undiscovered therapy. We herein found that cisplatin resistance of cancer cells comes at a fitness cost of increased intracellular hypoxia. Then, we conceived an inspired strategy to combat the tumor drug resistance by exploiting the increased intracellular hypoxia that occurs as the cells develop drug resistance. Here, we constructed a hypoxia-amplifying DNA repair-inhibiting liposomal nanomedicine (denoted as HYDRI NM), which is formulated from a platinum(IV) prodrug as a building block and payloads of glucose oxidase (GOx) and hypoxia-activatable tirapazamine (TPZ). In studies on clinically relevant models, including patient-derived organoids and patient-derived xenograft tumors, the HYDRI NM is able to effectively suppress the growth of cisplatin-resistant tumors. Thus, this study provides clinical proof of concept for the therapy identified here.

Immune Checkpoint Inhibitors in the Treatment of HCC

Hepatocellular carcinoma (HCC) is the typical inflammation-induced neoplasia. It often prospers where a chronic liver disease persists, thus leading a strong rationale for immune therapy. Several immune-based treatments, including immune checkpoint inhibitors (ICI), cytokines, adoptive cell transfer, and vaccines, have been tested in the treatment of HCC. In this review, we summarize the role of the ICI in HCC patients in various sets of treatment. As for advanced HCC, the anti-Programmed cell Death protein 1 (PD1) antibodies and the anti-Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) antibodies have been examined in patients with enthusiastic results in phase I-II-III studies. Overall, this led the Food and Drug Administration (FDA) to approve pembrolizumab, nivolumab, and nivolumab + ipilimumab in the second-line setting. The anti- Programmed Death-Ligand 1 (PDL-1) antibodies have also been evaluated. Thanks to the results obtained from phase III IMbrave study, atezolizumab + bevacizumab is now the standard of care in the first-line advanced setting of HCC. As for localized HCC, the putative immunological effect of locoregional therapies led to evaluate the combination strategy with ICI. This way, chemoembolization, ablation with radiofrequency, and radioembolization combined with ICI are currently under study. Likewise, the study of adjuvant immunotherapy following surgical resection is underway. In addition, the different ICI has been studied in combination with other ICI as well as with multikinase inhibitors and anti-angiogenesis monoclonal antibody. The evidence available suggests that combining systemic therapies and locoregional treatments with ICI may represent an effective strategy in this context.

Reprogramming of aerobic glycolysis in non-transformed mouse liver with pyruvate dehydrogenase complex deficiency

The Pyruvate Dehydrogenase Complex (PDC), a key enzyme in glucose metabolism, catalyzes an irreversible oxidative decarboxylation reaction of pyruvate to acetyl‐CoA, linking the cytosolic glycolytic pathway to mitochondrial tricarboxylic acid cycle and oxidative phosphorylation. Earlier we reported a down‐regulation of several key hepatic lipogenic enzymes and their upstream regulators in liver‐specific PDC‐deficient mouse (L‐PDCKO model by deleting the Pdha1 gene). In this study we investigated gene expression profiles of key glycolytic enzymes and other proteins that respond to various metabolic stresses in liver from L‐PDCKO mice. Transcripts of several, such as hexokinase 2, phosphoglycerate kinase 1, pyruvate kinase muscle‐type 2, and lactate dehydrogenase B as well as those for the nonglycolysis‐related proteins, CD‐36, C/EBP homologous protein, and peroxisome proliferator‐activated receptor γ, were up‐regulated in L‐PDCKO liver whereas hypoxia‐induced factor‐1α, pyruvate dehydrogenase kinase 1 and Sirtuin 1 transcripts were down‐regulated. The protein levels of pyruvate kinase muscle‐type 2 and lactate dehydrogenase B were increased whereas that of lactate dehydrogenase A was decreased in PDC‐deficient mouse liver. Analysis of endoplasmic reticulum and oxidative stress indicators suggests that the L‐PDCKO liver showed evidence of the former but not the latter. These findings indicate that (i) liver‐specific PDC deficiency is sufficient to induce “aerobic glycolysis characteristic” in mouse liver, and (ii) the mechanism(s) responsible for these changes appears distinct from that which induces the Warburg effect in some cancer cells.

Characterizing Endocrine Status, Tumor Hypoxia and Immunogenicity for Therapy Success in Epithelial Ovarian Cancer

Epithelial ovarian cancer is predominantly diagnosed at advanced stages which creates significant therapeutic challenges. As a result, the 5-year survival rate is low. Within ovarian cancer, significant tumor heterogeneity exists, and the tumor microenvironment is diverse. Tumor heterogeneity leads to diversity in therapy response within the tumor, which can lead to resistance or recurrence. Advancements in therapy development and tumor profiling have initiated a shift from a "one-size-fits-all" approach towards precision patient-based therapies. Here, we review aspects of ovarian tumor heterogeneity that facilitate tumorigenesis and contribute to treatment failure. These tumor characteristics should be considered when designing novel therapies or characterizing mechanisms of treatment resistance. Individual patients vary considerably in terms of age, fertility and contraceptive use which innately affects the endocrine milieu in the ovary. Similarly, individual tumors differ significantly in their immune profile, which can impact the efficacy of immunotherapies. Tumor size, presence of malignant ascites and vascular density further alters the tumor microenvironment, creating areas of significant hypoxia that is notorious for increasing tumorigenesis, resistance to standard of care therapies and promoting stemness and metastases. We further expand on strategies aimed at improving oxygenation status in tumors to dampen downstream effects of hypoxia and set the stage for better response to therapy.

JmjC-KDMs KDM3A and KDM6B modulate radioresistance under hypoxic conditions in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC), the most frequent esophageal cancer (EC) subtype, entails dismal prognosis. Hypoxia, a common feature of advanced ESCC, is involved in resistance to radiotherapy (RT). RT response in hypoxia might be modulated through epigenetic mechanisms, constituting novel targets to improve patient outcome. Post-translational methylation in histone can be partially modulated by histone lysine demethylases (KDMs), which specifically removes methyl groups in certain lysine residues. KDMs deregulation was associated with tumor aggressiveness and therapy failure. Thus, we sought to unveil the role of Jumonji C domain histone lysine demethylases (JmjC-KDMs) in ESCC radioresistance acquisition. The effectiveness of RT upon ESCC cells under hypoxic conditions was assessed by colony formation assay. KDM3A/KDM6B expression, and respective H3K9me2 and H3K27me3 target marks, were evaluated by RT-qPCR, Western blot, and immunofluorescence. Effect of JmjC-KDM inhibitor IOX1, as well as KDM3A knockdown, in in vitro functional cell behavior and RT response was assessed in ESCC under hypoxic conditions. In vivo effect of combined IOX1 and ionizing radiation treatment was evaluated in ESCC cells using CAM assay. KDM3A, KDM6B, HIF-1α, and CAIX immunoexpression was assessed in primary ESCC and normal esophagus. Herein, we found that hypoxia promoted ESCC radioresistance through increased KDM3A/KDM6B expression, enhancing cell survival and migration and decreasing DNA damage and apoptosis, in vitro. Exposure to IOX1 reverted these features, increasing ESCC radiosensitivity and decreasing ESCC microtumors size, in vivo. KDM3A was upregulated in ESCC tissues compared to the normal esophagus, associating and colocalizing with hypoxic markers (HIF-1α and CAIX). Therefore, KDM3A upregulation in ESCC cell lines and primary tumors associated with hypoxia, playing a critical role in EC aggressiveness and radioresistance. KDM3A targeting, concomitant with conventional RT, constitutes a promising strategy to improve ESCC patients' survival.

The role of Krüppel-like factor 8 in cancer biology: Current research and its clinical relevance

Cancer is one of the leading causes of mortality worldwide, ranked second after heart disease. Despite recent advancements in diagnosis and treatment, there are still numerous problems associated with cancer progression, disease recurrence, and therapeutic resistance that are partially explored. Several studies have recently revealed that Krüppel-like factor 8 (KLF8) regulates transcription of genes linked with diverse biological processes, including proliferation, epithelial to mesenchymal transition (EMT), migration, invasion, and inflammation. KLF8 is expressed ubiquitously in mammalian cells, and its aberrant expression has been manifested with several cancer types. Earlier studies demonstrated the crucial role of KLF8 in DNA repair and resistance to apoptosis in numerous cancer types. Hence, studying the function of KLF8 from the perspective of cancer progression and therapy resistance would help develop a new therapeutic avenue. In this review, we summarize the clinical relevance of KLF8 expression in various malignancies, focusing on recent updates in EMT, cellular signaling, and cancer stem cells. We also address the contribution of KLF8 in development, DNA repair, chemoresistance, and its clinical utility as a predictive biomarker.

Identification and validation of a six-gene signature associated with glycolysis to predict the prognosis of patients with cervical cancer

BACKGROUND

Cervical cancer (CC) is one of the most common gynaecological cancers. The gene signature is believed to be reliable for predicting cancer patient survival. However, there is no relevant study on the relationship between the glycolysis-related gene (GRG) signature and overall survival (OS) of patients with CC.

METHODS

We extracted the mRNA expression profiles of 306 tumour and 13 normal tissues from the University of California Santa Cruz (UCSC) Database. Then, we screened out differentially expressed glycolysis-related genes (DEGRGs) among these mRNAs. All patients were randomly divided into training cohort and validation cohort according to the ratio of 7: 3. Next, univariate and multivariate Cox regression analyses were carried out to select the GRG with predictive ability for the prognosis of the training cohort. Additionally, risk score model was constructed and validated it in the validation cohort.

RESULTS

Six mRNAs were obtained that were associated with patient survival. The filtered mRNAs were classified into the protective type (GOT1) and the risk type (HSPA5, ANGPTL4, PFKM, IER3 and PFKFB4). Additionally, by constructing the prognostic risk score model, we found that the OS of the high-risk group was notably poorer, which showed good predictive ability both in training cohort and validation cohort. And the six-gene signature is a prognostic indicator independent of clinicopathological features. Through the verification of PCR, the results showed that compared with the normal cervial tissuses, the expression level of six mRNAs were significantly higher in the CC tissue, which was consistent with our findings.

CONCLUSIONS

We constructed a glycolysis-related six-gene signature to predict the prognosis of patients with CC using bioinformatics methods. We provide a thorough comprehension of the effect of glycolysis in patients with CC and provide new targets and ideas for individualized treatment.

Vascular disrupting agents in cancer therapy

Tumor blood vessel formation is a key process for tumor expansion. Tumor vessels are abnormal and differ from normal vessels in architecture and components. Besides oxygen and nutrients supply, the tumor vessels system, due to its abnormality, is responsible for: hypoxia formation, and metastatic routes. Tumor blood vessels can be a target of anti-cancer therapies. There are two types of therapies that target tumor vessels. The first one is the inhibition of the angiogenesis process. However, the inhibition is often ineffective because of alternative angiogenesis mechanism activation. The second type is a specific targeting of existing tumor blood vessels by vascular disruptive agents (VDAs). There are three groups of VDAs: microtubule destabilizing drugs, flavonoids with anti-vascular functions, and tumor vascular targeted drugs based on endothelial cell receptors. However, VDAs possess some limitations. They may be cardiotoxic and their application in therapy may leave viable residual, so called, rim cells on the edge of the tumor. However, it seems that a well-designed combination of VDAs with other anti-cancer drugs may bring a significant therapeutic effect. In this article, we describe three groups of vascular disruptive agents with their advantages and disadvantages. We mention VDAs clinical trials. Finally, we present the current possibilities of VDAs combination with other anti-cancer drugs.

Neutrophil-Mediated Cardiac Damage After Acute Myocardial Infarction: Significance of Defining a New Target Cell Type for Developing Cardioprotective Drugs

Significance: Acute myocardial infarction (AMI) is a leading cause of death worldwide. Post-AMI survival rates have increased with the introduction of angioplasty as a primary coronary intervention. However, reperfusion after angioplasty represents a clinical paradox, restoring blood flow to the ischemic myocardium while simultaneously inducing ion and metabolic imbalances that stimulate immune cell recruitment and activation, mitochondrial dysfunction and damaging oxidant production. Recent Advances: Preclinical data indicate that these metabolic imbalances contribute to subsequent heart failure through sustaining local recruitment of inflammatory leukocytes and oxidative stress, cardiomyocyte death, and coronary microvascular disturbances, which enhance adverse cardiac remodeling. Both left ventricular dysfunction and heart failure are strongly linked to inflammation and immune cell recruitment to the damaged myocardium. Critical Issues: Overall, therapeutic anti-inflammatory and antioxidant agents identified in preclinical trials have failed in clinical trials. Future Directions: The versatile neutrophil-derived heme enzyme, myeloperoxidase (MPO), is gaining attention as an important oxidative mediator of reperfusion injury, vascular dysfunction, adverse ventricular remodeling, and atrial fibrillation. Accordingly, there is interest in therapeutically targeting neutrophils and MPO activity in the setting of heart failure. Herein, we discuss the role of post-AMI inflammation linked to myocardial damage and heart failure, describe previous trials targeting inflammation and oxidative stress post-AMI, highlight the potential adverse impact of neutrophil and MPO, and detail therapeutic options available to target MPO clinically in AMI patients.

Cancer stem cells and their niche in the progression of squamous cell carcinoma

Most cancers harbor a small population of highly tumorigenic cells known as cancer stem cells (CSCs). Because of their stem cell-like properties and resistance to conventional therapies, CSCs are considered to be a rational target for curable cancer treatment. However, despite recent advances in CSC research, CSC-targeted therapies are not as successful as was initially hoped. The proliferative, invasive, and drug-resistant properties of CSCs are regulated by the tumor microenvironment associated with them, the so-called CSC niche. Thus, targeting tumor-promoting cellular crosstalk between CSCs and their niches is an attractive avenue for developing durable therapies. Using mouse models of squamous cell carcinoma (SCC), we have demonstrated that tumor cells responding to transforming growth factor β (TGF-β) function as drug-resistant CSCs. The gene expression signature of TGF-β-responding tumor cells has accelerated the identification of novel pathways that drive invasive tumor progression. Moreover, by focusing on the cytokine milieu and macrophages in the proximity of TGF-β-responding tumor cells, we recently uncovered the molecular basis of a CSC-niche interaction that emerges during early tumor development. This review article summarizes the specialized tumor microenvironment associated with CSCs and discusses mechanisms by which malignant properties of CSCs are maintained and promoted.

LINK-A long non-coding RNA and VEGF RNA expression in epithelial ovarian cancer patients

LINK-A (long intergenic non-coding RNA for kinase activation) is a newly identified long non-coding RNA with oncogenic function, which leads to the hyperactivation of AKT and HIF1α. thereby, fosters cell proliferation, mobility and metastasis. VEGF (vascular endothelial growth factor), a well-known cytokine has an important role in angiogenesis. In this study, we quantified RNA expression of LINK-A and VEGF on 45 tumor specimens obtained from Iranian patients diagnosed with Epithelial Ovarian Cancer (EOC). Our goal was to evaluate expression of LINK-A lncRNA and VEGF mRNA in ovarian cancer tissues and find the probable correlation of LINK-A with VEGF as a major transcription target for HIF1α. LINK-A and VEGF were remarkably overexpressed in EOC tissues compared to normal tissues (P value: 0.004, 0.0001, respectively), but we did not find correlation between LINK-A and VEGF RNA expressions in this study. LINK-A was significantly overexpressed in higher stages of cancer and tumor grades. VEGF was only significantly elevated in higher stages. This study confirms importance of novel lncRNA of LINK-A in Iranian EOC patients.

Metabolic Potential of Cancer Cells in Context of the Metastatic Cascade

The metastatic cascade is a highly plastic and dynamic process dominated by cellular heterogeneity and varying metabolic requirements. During this cascade, the three major metabolic pillars, namely biosynthesis, RedOx balance, and bioenergetics, have variable importance. Biosynthesis has superior significance during the proliferation-dominated steps of primary tumour growth and secondary macrometastasis formation and only minor relevance during the growth-independent processes of invasion and dissemination. Consequently, RedOx homeostasis and bioenergetics emerge as conceivable metabolic key determinants in cancer cells that disseminate from the primary tumour. Within this review, we summarise our current understanding on how cancer cells adjust their metabolism in the context of different microenvironments along the metastatic cascade. With the example of one-carbon metabolism, we establish a conceptual view on how the same metabolic pathway can be exploited in different ways depending on the current cellular needs during metastatic progression.

Heparanase from triple‑negative breast cancer and platelets acts as an enhancer of metastasis

Triple-negative breast cancer (TNBC), which is characterized by inherently aggressive behavior and lack of recognized molecular targets for therapy, poses a serious threat to women's health worldwide. However, targeted treatments have yet to be made available. A crosstalk between tumor cells and platelets (PLT) contributing to growth, angiogenesis and metastasis has been reported in numerous cancers. Heparanase (Hpa), the only mammalian endoglycosidase that cleaves heparan sulfate, has been demonstrated to contribute to the growth, angiogenesis and metastasis of numerous cancers. Hypoxia affects the growth, angiogenesis and metastasis of nearly all solid tumors, and the ability of Hpa to promote invasion is enhanced in hypoxia. However, whether Hpa can strengthen the crosstalk between tumor cells and PLT, and whether enhancing the biological function of Hpa in TNBC promotes malignant progression, have yet to be fully elucidated. The present study, based on bioinformatics analysis and experimental studies in vivo and in vitro, demonstrated that Hpa enhanced the crosstalk between TNBC cells and PLT to increase the supply of oxygen and nutrients, while also conferring tolerance of TNBC cells to oxygen and nutrient shortage, both of which are important for overcoming the stress of hypoxia and nutritional deprivation in the tumor microenvironment, thereby promoting malignant progression, including growth, angiogenesis and metastasis in TNBC. In addition, the hypoxia-inducible factor-1a (HIF-1a)/vascular endothelial growth factor-a (VEGF- a)/phosphorylated protein kinase B (p-)Akt axis may be the key pathway involved in the effects of Hpa on the biological processes mentioned above. Therefore, improving local hypoxia, anti-Hpa treatment and inhibiting PLT activation may improve the prognosis of TNBC.

HLA-G Neo-Expression on Tumors

HLA-G is known to modulate the immune system activity in tissues where physiological immune-tolerance is necessary (i.e., maternal-fetal interface, thymus, and cornea). However, the frequent neo-expression of HLA-G in many cancer types has been previously and extensively described and is correlated with a bad prognosis. Despite being an MHC class I molecule, HLA-G is highly present in tumor context and shows unique characteristics of tissue restriction of a Tumor Associated Antigen (TAA), and potent immunosuppressive activity of an Immune CheckPoint (ICP). Consequently, HLA-G appears to be an excellent molecular target for immunotherapy. Although the relevance of HLA-G in cancer incidence and development has been proven in numerous tumors, its neo-expression pattern is still difficult to determine. Indeed, the estimation of HLA-G's actual expression in tumor tissue is limited, particularly concerning the presence and percentage of the new non-canonical isoforms, for which detection antibodies are scarce or inexistent. Here, we summarize the current knowledge about HLA-G neo-expression and implication in various tumor types, pointing out the need for the development of new tools to analyze in-depth the HLA-G neo-expression patterns, opening the way for the generation of new monoclonal antibodies and cell-based immunotherapies.

Metabolic regulation in HPV associated head and neck squamous cell carcinoma

Cancer cells exhibit distinct energy metabolic pathways due to multiple oncogenic events. In normoxia condition, the anaerobic glycolysis (Warburg effect) is highly observed in head and neck squamous cell carcinoma (HNSCC). HNSCC is associated with smoking, chewing tobacco, consumption of alcohol or Human Papillomavirus (HPV) infection primarily HPV16. In recent years, the correlation of HPV with HNSCC has significantly expanded. Despite the recent advancement in therapeutic approaches, the rate of HPV infected HNSCC has significantly increased in the last few years, specifically, in lower middle-income countries. The oncoproteins of High-risk Human Papillomavirus (HR-HPV), E6 and E7, alter the metabolic phenotype in HNSCC, which is distinct from non-HPV associated HNSCC. These oncoproteins, modulate the cell cycle and metabolic signalling through interacting with tumor suppressor proteins, p53 and pRb. Since, metabolic alteration represents a major hallmark for tumorigenesis, HPV acts as a source of biomarker linked to cancer progression in HNSCC. The dependency of cancer cells to specific nutrients and alteration of various metabolic associated genes may provide a unique opportunity for pharmacological intervention in HPV infected HNSCC. In this review, we have discussed the molecular mechanism (s) and metabolic regulation in HNSCC depending on the HPV status. We have also discussed the possible potential therapeutic approaches for HPV associated HNSCC through targeting metabolic pathways.

Oxygen sensing; a stunningly elegant molecular machinery highjacked in cancer

Oxygen is of fundamental importance for most living organisms, and the maintenance of oxygen homeostasis is a key physiological challenge for all large animals. Oxygen deprivation, hypoxia, is a critical component of many human diseases including cancer, heart disease, stroke, vascular disease, and anaemia. The discovery of oxygen sensing provides fundamental knowledge of a stunningly elegant molecular machinery; it also promises development of new therapeutics for serious diseases such as cancer. As a result of their impressive contributions to our understanding of the mechanisms by which cells sense oxygen and signal in hypoxia, Gregg Semenza, Peter Ratcliffe, and William Kaelin were awarded the Nobel Prize in 2019.

Glycolysis, via NADH-dependent dimerisation of CtBPs, regulates hypoxia-induced expression of CAIX and stem-like breast cancer cell survival

Adaptive responses to hypoxia are mediated by the hypoxia-inducible factor (HIF) family of transcription factors. These responses include the upregulation of glycolysis to maintain ATP production. This also generates acidic metabolites, which require HIF-induced carbonic anhydrase IX (CAIX) for their neutralisation. C-terminal binding proteins (CtBPs) are coregulators of gene transcription and couple glycolysis with gene transcription due to their regulation by the glycolytic coenzyme NADH. Here, we find that experimental manipulation of glycolysis and CtBP function in breast cancer cells through multiple complementary approaches supports a hypothesis whereby the expression of known HIF-inducible genes, and CAIX in particular, adapts to available glucose in the microenvironment through a mechanism involving CtBPs. This novel pathway promotes the survival of stem cell-like cancer (SCLC) cells in hypoxia.

Oxygen sensing decoded: a Nobel concept in biology

Oxygen is essential to most organisms as it is a necessity for aerobic metabolism and energy production. Too much or too little oxygen can be deadly, such that mechanisms for fast and titrated response to changing oxygen levels are crucial. These mechanisms have evolved from the studies of Gregg L. Semenza, William G. Kaelin and Peter J. Ratcliffe. It is through the work of their three laboratories, performed in the 1990s, that the cellular oxygen sensing mechanisms have been decoded. Their discoveries have had major impact for innovation in medicine, especially in the field of angiogenesis research, where oxygen sensing and its consequences have led to enhanced insight in vascular development and strategies for combating angiogenic diseases. On October 7, the Nobel Assembly in Stockholm announced at the Karolinska Institute that the Nobel Prize for Medicine 2019 is jointly awarded to these three scientists for their seminal discoveries on how cells sense and respond to oxygen.

TiPARP forms nuclear condensates to degrade HIF-1α and suppress tumorigenesis

Precisely controlling the activation of transcription factors is crucial for physiology. After a transcription factor is activated and carries out its transcriptional activity, it also needs to be properly deactivated. Here, we report a deactivation mechanism of HIF-1 and several other oncogenic transcription factors. HIF-1 promotes the transcription of an ADP ribosyltransferase, TiPARP, which serves to deactivate HIF-1. Mechanistically, TiPARP forms distinct nuclear condensates or nuclear bodies in an ADP ribosylation-dependent manner. The TiPARP nuclear bodies recruit both HIF-1α and an E3 ubiquitin ligase HUWE1, which promotes the ubiquitination and degradation of HIF-1α. Similarly, TiPARP promotes the degradation of c-Myc and estrogen receptor. By suppressing HIF-1α and other oncogenic transcription factors, TiPARP exerts strong antitumor effects both in cell culture and in mouse xenograft models. Our work reveals TiPARP as a negative-feedback regulator for multiple oncogenic transcription factors, provides insights into the functions of protein ADP-ribosylation, and suggests activating TiPARP as an anticancer strategy.

PPAR Beta/Delta and the Hallmarks of Cancer

Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor family. Three different isoforms, PPAR alpha, PPAR beta/delta and PPAR gamma have been identified. They all form heterodimers with retinoic X receptors to activate or repress downstream target genes dependent on the presence/absence of ligands and coactivators or corepressors. PPARs differ in their tissue expression profile, ligands and specific agonists and antagonists. PPARs attract attention as potential therapeutic targets for a variety of diseases. PPAR alpha and gamma agonists are in clinical use for the treatment of dyslipidemias and diabetes. For both receptors, several clinical trials as potential therapeutic targets for cancer are ongoing. In contrast, PPAR beta/delta has been suggested as a therapeutic target for metabolic syndrome. However, potential risks in the settings of cancer are less clear. A variety of studies have investigated PPAR beta/delta expression or activation/inhibition in different cancer cell models in vitro, but the relevance for cancer growth in vivo is less well documented and controversial. In this review, we summarize critically the knowledge of PPAR beta/delta functions for the different hallmarks of cancer biological capabilities, which interplay to determine cancer growth.

Targeting Angiotensin-Converting Enzyme-2/Angiotensin-(1-7)/Mas Receptor Axis in the Vascular Progenitor Cells for Cardiovascular Diseases

Bone marrow-derived hematopoietic stem/progenitor cells are vasculogenic and play an important role in endothelial health and vascular homeostasis by participating in postnatal vasculogenesis. Progenitor cells are mobilized from bone marrow niches in response to remote ischemic injury and migrate to the areas of damage and stimulate revascularization largely by paracrine activation of angiogenic functions in the peri-ischemic vasculature. This innate vasoprotective mechanism is impaired in certain chronic clinical conditions, which leads to the development of cardiovascular complications. Members of the renin-angiotensin system-angiotensin-converting enzymes (ACEs) ACE and ACE2, angiotensin II (Ang II), Ang-(1-7), and receptors AT1 and Mas-are expressed in vasculogenic progenitor cells derived from humans and rodents. Ang-(1-7), generated by ACE2, is known to produce cardiovascular protective effects by acting on Mas receptor and is considered as a counter-regulatory mechanism to the detrimental effects of Ang II. Evidence has now been accumulating in support of the activation of the ACE2/Ang-(1-7)/Mas receptor pathway by pharmacologic or molecular maneuvers, which stimulates mobilization of progenitor cells from bone marrow, migration to areas of vascular damage, and revascularization of ischemic areas in pathologic conditions. This minireview summarizes recent studies that have enhanced our understanding of the physiology and pharmacology of vasoprotective axis in bone marrow-derived progenitor cells in health and disease. SIGNIFICANCE STATEMENT: Hematopoietic stem progenitor cells (HSPCs) stimulate revascularization of ischemic areas. However, the reparative potential is diminished in certain chronic clinical conditions, leading to the development of cardiovascular diseases. ACE2 and Mas receptor are key members of the alternative axis of the renin-angiotensin system and are expressed in HSPCs. Accumulating evidence points to activation of ACE2 or Mas receptor as a promising approach for restoring the reparative potential, thereby preventing the development of ischemic vascular diseases.

Hypoxia drives glucose transporter 3 expression through hypoxia-inducible transcription factor (HIF)-mediated induction of the long noncoding RNA NICI

Hypoxia-inducible transcription factors (HIFs) directly dictate the expression of multiple RNA species including novel and as yet uncharacterized long noncoding transcripts with unknown function. We used pan-genomic HIF-binding and transcriptomic data to identify a novel long noncoding RNA Noncoding Intergenic Co-Induced transcript (NICI) on chromosome 12p13.31 which is regulated by hypoxia via HIF-1 promoter-binding in multiple cell types. CRISPR/Cas9-mediated deletion of the hypoxia-response element revealed co-regulation of NICI and the neighboring protein-coding gene, solute carrier family 2 member 3 (SLC2A3) which encodes the high-affinity glucose transporter 3 (GLUT3). Knockdown or knockout of NICI attenuated hypoxic induction of SLC2A3, indicating a direct regulatory role of NICI in SLC2A3 expression, which was further evidenced by CRISPR/Cas9-VPR-mediated activation of NICI expression. We also demonstrate that regulation of SLC2A3 is mediated through transcriptional activation rather than posttranscriptional mechanisms because knockout of NICI leads to reduced recruitment of RNA polymerase 2 to the SLC2A3 promoter. Consistent with this we observe NICI-dependent regulation of glucose consumption and cell proliferation. Furthermore, NICI expression is regulated by the von Hippel-Lindau (VHL) tumor suppressor and is highly expressed in clear cell renal cell carcinoma (ccRCC), where SLC2A3 expression is associated with patient prognosis, implying an important role for the HIF/NICI/SLC2A3 axis in this malignancy.

Recent advances in the biology of tumour hypoxia with relevance to diagnostic practice and tissue-based research

In this review article, we examine the importance of low levels of oxygen (hypoxia) in cancer biology. We provide a brief description of how mammalian cells sense oxygen. The hypoxia-inducible factor (HIF) pathway is currently the best characterised oxygen-sensing system, but recent work has revealed that mammals also use an oxygen-sensing system found in plants to regulate the abundance of some proteins and peptides with an amino-terminal cysteine residue. We discuss how the HIF pathway is affected during the growth of solid tumours, which develop in microenvironments with gradients of oxygen availability. We then introduce the concept of 'pseudohypoxia', a state of constitutive, oxygen-independent HIF system activation that occurs due to oncogenic stimulation in a number of specific tumour types that are of immediate relevance to diagnostic histopathologists. We provide an overview of the different methods of quantifying tumour hypoxia, emphasising the importance of pre-analytic factors in interpreting the results of tissue-based studies. Finally, we review recent approaches to targeting hypoxia/HIF system activation for therapeutic benefit, the application of which may require knowledge of which hypoxia signalling components are being utilised by a given tumour. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Angiogenesis in primary colorectal cancer and matched metastatic tissues: Biological and clinical implications for anti-angiogenic therapies

Metastasis remains a notable issue in patients with newly diagnosed colorectal carcinomas (CRC). Although anti-angiogenic therapies target metastatic diseases, hypoxia-inducible factor-1 α (HIF-1α) and vascular endothelial growth factor (VEGF) status are routinely evaluated in primary tumors as metastatic sites are infrequently biopsied. The present study aimed to investigate the expression and significance of HIF-1α, VEGF and microvascular density (MVD) in primary tumors and corresponding metastatic CRC tissues. HIF-1α, VEGF and CD34 status were analyzed via immunohistochemistry analysis in 46 patients who underwent surgical resection of primary CRC (35 colon and 11 rectum) and matched metastases (lymph node and liver metastases) in Shandong Cancer Hospital. The association between selected biomarker status and clinicopathological characteristics was analyzed, and expression levels in primary tumors and corresponding metastases were compared. A total of 46 paired colorectal primary tumor and synchronous metastases samples were acquired for analysis using a standardized HIF-1α, VEGF and CD34 immunohistochemical procedure. The results demonstrated that the positive rates of HIF-1α and VEGF in primary CRC were 70 and 73.9%, respectively. HIF-1α (60.9%) and VEGF (58.7%) expression decreased in the lymph metastatic samples compared with primary CRC. Conversely, the level of MVD in primary tumors was significantly higher compared with metastatic tumors. No significant differences were demonstrated between HIF-1α and VEGF expression and the different clinicopathological features in primary CRC and corresponding metastases. Primary carcinomas and matched metastatic tissues demonstrated a moderate level of consistent immunoreactivity for HIF-1α and VEGF. HIF-1α, VEGF and CD34 were expressed in both primary tumors and corresponding metastases of CRC, suggesting that they may be involved in the development of metastasis. HIF-1α and VEGF expression in primary sites was consistent with that observed in metastases; however, it varied from that exhibited in MVD. The current analysis will improve the current understanding of the metastasis models and provide further evidence for evaluating the response to HIF-1α and VEGF inhibitors.

Molecular and functional imaging insights into the role of hypoxia in cancer aggression

Hypoxia in cancers has evoked significant interest since 1955 when Thomlinson and Gray postulated the presence of hypoxia in human lung cancers, based on the observation of necrosis occurring at the diffusion limit of oxygen from the nearest blood vessel, and identified the implication of these observations for radiation therapy. Coupled with discoveries in 1953 by Gray and others that anoxic cells were resistant to radiation damage, these observations have led to an entire field of research focused on exploiting oxygenation and hypoxia to improve the outcome of radiation therapy. Almost 65 years later, tumor heterogeneity of nearly every parameter measured including tumor oxygenation, and the dynamic landscape of cancers and their microenvironments are clearly evident, providing a strong rationale for cancer personalized medicine. Since hypoxia is a major cause of extracellular acidosis in tumors, here, we have focused on the applications of imaging to understand the effects of hypoxia in tumors and to target hypoxia in theranostic strategies. Molecular and functional imaging have critically important roles to play in personalized medicine through the detection of hypoxia, both spatially and temporally, and by providing new understanding of the role of hypoxia in cancer aggressiveness. With the discovery of the hypoxia-inducible factor (HIF), the intervening years have also seen significant progress in understanding the transcriptional regulation of hypoxia-induced genes. These advances have provided the ability to silence HIF and understand the associated molecular and functional consequences to expand our understanding of hypoxia and its role in cancer aggressiveness. Most recently, the development of hypoxia-based theranostic strategies that combine detection and therapy are further establishing imaging-based treatment strategies for precision medicine of cancer.

Putative mechanism for anticancer properties of Ag-PP (NPs) extract

One of the most important challenges in treating cancer is the invasion and the angiogenesis of cancer cells. The synthesis of green nanoparticles (NPs) and their use in therapeutic fields is one of the most effective methods with minimal side effects in cancer treatment. In this study, cytotoxic and anti-angiogenic effects of silver NPs (AgNPs) coated with palm pollen extract [Ag-PP(NPs)] were evaluated. For this purpose, the cells were treated with NPs and then were subjected to trypan blue testing (48 h). Then, the cancer invasion was evaluated by the scratch procedure and the expressions of the vascular endothelial growth factor (VEGF) and its receptor (VEGF-R) genes were estimated using real-time PCR assay. Also, the angiogenesis effect of the NPs was investigated with chick chorioallantoic membrane (CAM) assay. The Ag-PP(NPs) induced cytotoxicity on MCF7 cells. The findings also showed that Ag-PP(NPs) inhibit invasive cancer cells and reduce the expression of VEGF and VEGF-R and significantly reduced the number and vessels lengths and the lengths and weights of the embryos in CAM assay. Ag-PP(NPs) with the induction of cytotoxic effects, metastatic inhibition and anti-angiogenesis properties should be considered as an appropriate option for treatment of cancer.

Extracellular Matrix in the Tumor Microenvironment and Its Impact on Cancer Therapy

Solid tumors are complex organ-like structures that consist not only of tumor cells but also of vasculature, extracellular matrix (ECM), stromal, and immune cells. Often, this tumor microenvironment (TME) comprises the larger part of the overall tumor mass. Like the other components of the TME, the ECM in solid tumors differs significantly from that in normal organs. Intratumoral signaling, transport mechanisms, metabolisms, oxygenation, and immunogenicity are strongly affected if not controlled by the ECM. Exerting this regulatory control, the ECM does not only influence malignancy and growth of the tumor but also its response toward therapy. Understanding the particularities of the ECM in solid tumor is necessary to develop approaches to interfere with its negative effect. In this review, we will also highlight the current understanding of the physical, cellular, and molecular mechanisms by which the pathological tumor ECM affects the efficiency of radio-, chemo-, and immunotherapy. Finally, we will discuss the various strategies to target and modify the tumor ECM and how they could be utilized to improve response to therapy.

An Oxygen Sensation: Progress in Macromolecule Hydroxylation Triggered by the Elucidation of Cellular Oxygen Sensing

The 2019 Nobel Prize in Physiology or Medicine honours three scientists that devoted their careers to pursuing an audacious basic science question: by what mechanisms do animals sense oxygen, and how can cells adapt to a lack of oxygen? The identification of the human hypoxia inducible factor pathway has enabled new approaches for the therapy of related diseases including cancer, cardiovascular disease, anaemia, and stroke. The intricate molecular details of oxygen sensing broadened interest in the family of iron- and 2-oxoglutarate-dependent oxygenases known from elaborate natural product chemistry, and catalysed major progress in macromolecule hydroxylation. The laureates' work enables numerous avenues for molecular scientists, from C-H activation chemistry to PROTAC technology, medicinal chemistry, and epigenetics.

The VHL/HIF Axis in the Development and Treatment of Pheochromocytoma/Paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors originating from chromaffin cells in the adrenal medulla (PCCs) or extra-adrenal sympathetic or parasympathetic paraganglia (PGLs). About 40% of PPGLs result from germline mutations and therefore they are highly inheritable. Although dysfunction of any one of a panel of more than 20 genes can lead to PPGLs, mutations in genes involved in the VHL/HIF axis including PHD, VHL, HIF-2A (EPAS1), and SDHx are more frequently found in PPGLs. Multiple lines of evidence indicate that pseudohypoxia plays a crucial role in the tumorigenesis of PPGLs, and therefore PPGLs are also known as metabolic diseases. However, the interplay between VHL/HIF-mediated pseudohypoxia and metabolic disorder in PPGLs cells is not well-defined. In this review, we will first discuss the VHL/HIF axis and genetic alterations in this axis. Then, we will dissect the underlying mechanisms in VHL/HIF axis-driven PPGL pathogenesis, with special attention paid to the interplay between the VHL/HIF axis and cancer cell metabolism. Finally, we will summarize the currently available compounds/drugs targeting this axis which could be potentially used as PPGLs treatment, as well as their underlying pharmacological mechanisms. The overall goal of this review is to better understand the role of VHL/HIF axis in PPGLs development, to establish more accurate tools in PPGLs diagnosis, and to pave the road toward efficacious therapeutics against metastatic PPGLs.

Overexpression of VEGF-C and MMP-9 predicts poor prognosis in Kazakh patients with esophageal squamous cell carcinoma

Vascular endothelial growth factor (VEGF) and Matrix metalloproteinases (MMPs) are believed to participate in infiltration of tumors. High mortality of esophageal squamous cell carcinoma (ESCC) related to its primary infiltration; however, it is not clear whether the expression of VEGF and MMPs is involved in this process. Screening of The Cancer Genome Atlas (TCGA) database showed that among the VEGF family and MMP9, VEGF-A, VEGF-C, and MMP-9 mRNA were overexpression in ESCC. This result was verified using the Oncomine database and in Kazakh patients with ESCC. Overexpression of VEGF-C and MMP-9 and positive association with advanced esophageal cancer and invading ESCC cells (Gene Expression Omnibus (GEO): GSE21293). Immunohistochemical staining revealed that VEGF-C and MMP-9 were overexpressed in Kazakh ESCCs. VEGF-C expression was related to invasive depth, tumor-node-metastasis (TNM) staging, lymphatic, and lymph node metastasis of ESCC. The linear association between them was further confirmed in TCGA database and the specimens from Kazakh patients with ESCC. Patients with both proteins expression had tumors with greater aggressiveness, suffered from poor prognosis compared with patients who did not express either protein or expressed protein alone. Both proteins expression predicted high invasiveness of ESCC, which is related to worse prognosis of Kazakh ESCCs.

Model genotype-phenotype mappings and the algorithmic structure of evolution

Cancers are complex dynamic systems that undergo evolution and selection. Personalized medicine approaches in the clinic increasingly rely on predictions of tumour response to one or more therapies; these predictions are complicated by the inevitable evolution of the tumour. Despite enormous amounts of data on the mutational status of cancers and numerous therapies developed in recent decades to target these mutations, many of these treatments fail after a time due to the development of resistance in the tumour. The emergence of these resistant phenotypes is not easily predicted from genomic data, since the relationship between genotypes and phenotypes, termed the genotype-phenotype (GP) mapping, is neither injective nor functional. We present a review of models of this mapping within a generalized evolutionary framework that takes into account the relation between genotype, phenotype, environment and fitness. Different modelling approaches are described and compared, and many evolutionary results are shown to be conserved across studies despite using different underlying model systems. In addition, several areas for future work that remain understudied are identified, including plasticity and bet-hedging. The GP-mapping provides a pathway for understanding the potential routes of evolution taken by cancers, which will be necessary knowledge for improving personalized therapies.