Hypoxia-Inducible Factor-1: A Novel Therapeutic Target for the Management of Cancer, Drug Resistance, and Cancer-Related Pain

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.

2-methoxyestradiol sensitizes tamoxifen-resistant MCF-7 breast cancer cells via downregulating HIF-1α

The clinical studies for breast cancer (BC) are now assessing the efficacy of 2-Methoxyestradiol (2-ME), a naturally occurring derivative of estradiol. Our study aimed to explore the potential of combining the 2-ME and tamoxifen (TAM) on sensitization of TAM-resistant cells using LCC2 the TAM-resistant cells as a model and comparing the results to the sensitive cells MCF-7. Sulphorhodamine-B (SRB) assay is used to examine the 2-ME chemo-sensitizing impact on the cytotoxicity of TAM on LCC2 cells. Colorimetric assay kits were used to assess the level of the apoptosis-related markers caspases 3, Bcl2, and Bax in cell lysate. Hypoxia-inducible factor 1 alpha (HIF-1α) expression was measured using western blotting. Total cholesterol and triglyceride (TG) levels were examined colorimetrically, using the BIOLABO kit. The use of 2-ME enhanced the cytotoxic effects of TAM and effectively reversed TAM resistance. This was achieved by inhibiting the expression of HIF-1α, while concurrently increasing the levels of apoptotic marker caspase-3, as well as the pro-apoptotic protein Bax. Additionally, there was a reduction in the levels of Bcl2, an anti-apoptotic protein. Furthermore, a reduction in TG and cholesterol levels was noted. Our findings show that HIF-1α plays an important role in TAM resistance and that suppression of HIF-1α by 2-ME-mediated sensitization of BC-resistant cells to TAM. Therefore, the concurrent administration of TAM/2-ME might potentially serve as a viable therapeutic approach to address TAM resistance and enhance the overall therapy efficacy for patients with BC.

Role of hypoxia-inducible factor 1 in type 1 diabetes

Type 1 diabetes (T1D) is a common autoimmune disease in which dysregulated glucose metabolism is a key feature. T1D is both poorly understood and in need of improved therapeutics. Hypoxia is frequently encountered in multiple tissues in T1D patients including the pancreas and sites of diabetic complications. Hypoxia-inducible factor (HIF)-1, a ubiquitous master regulator of the adaptive response to hypoxia, promotes glucose metabolism through transcriptional and non-transcriptional mechanisms and alters disease progression in multiple preclinical T1D models. However, how HIF-1 activation in β-cells of the pancreas and immune cells (two key cell types in T1D) ultimately affects disease progression remains controversial. We discuss recent advances in our understanding of the role of hypoxia/HIF-1-induced glycolysis in T1D and explore the possible use of drugs targeting this pathway as potential new therapeutics.

Targeted Cancer Therapy-on-A-Chip

Targeted cancer therapy (TCT) is gaining increased interest because it reduces the risks of adverse side effects by specifically treating tumor cells. TCT testing has traditionally been performed using two-dimensional (2D) cell culture and animal studies. Organ-on-a-chip (OoC) platforms have been developed to recapitulate cancer in vitro, as cancer-on-a-chip (CoC), and used for chemotherapeutics development and testing. This review explores the use of CoCs to both develop and test TCTs, with a focus on three main aspects, the use of CoCs to identify target biomarkers for TCT development, the use of CoCs to test free, un-encapsulated TCTs, and the use of CoCs to test encapsulated TCTs. Despite current challenges such as system scaling, and testing externally triggered TCTs, TCToC shows a promising future to serve as a supportive, pre-clinical platform to expedite TCT development and bench-to-bedside translation.

Dynamics of Endothelial Cell Diversity and Plasticity in Health and Disease

Endothelial cells (ECs) are vital structural units of the cardiovascular system possessing two principal distinctive properties: heterogeneity and plasticity. Endothelial heterogeneity is defined by differences in tissue-specific endothelial phenotypes and their high predisposition to modification along the length of the vascular bed. This aspect of heterogeneity is closely associated with plasticity, the ability of ECs to adapt to environmental cues through the mobilization of genetic, molecular, and structural alterations. The specific endothelial cytoarchitectonics facilitate a quick structural cell reorganization and, furthermore, easy adaptation to the extrinsic and intrinsic environmental stimuli, known as the epigenetic landscape. ECs, as universally distributed and ubiquitous cells of the human body, play a role that extends far beyond their structural function in the cardiovascular system. They play a crucial role in terms of barrier function, cell-to-cell communication, and a myriad of physiological and pathologic processes. These include development, ontogenesis, disease initiation, and progression, as well as growth, regeneration, and repair. Despite substantial progress in the understanding of endothelial cell biology, the role of ECs in healthy conditions and pathologies remains a fascinating area of exploration. This review aims to summarize knowledge and concepts in endothelial biology. It focuses on the development and functional characteristics of endothelial cells in health and pathological conditions, with a particular emphasis on endothelial phenotypic and functional heterogeneity.

Preliminary study on cytotoxicity of selegiline on different cancer cell lines: exploration of the induction of ROS-independent apoptosis in breast cancer cells

The concept of drug repurposing is now widely utilized by biomedical scientists for drug discovery. An example of this is the use of selegiline (SEL), a monoamine oxidase inhibitor that was initially used for the management of depression but is now being considered for another purpose. This study compares the cytotoxic effects of SEL on different cancer cells. Further, the study explores the molecular mechanism of cell death, validating the possibility of its repurposing for cancer. Preliminary analysis of network pharmacological data was conducted in silico, followed by in vitro cytotoxicity tests on PC12, G361, MDA-MB231, MCF7, THP-1, and Hela cells under normoxic and hypoxic conditions, using the MTT assay. The mechanism of cell death was then confirmed by performing DAPI and FITC-conjugated Annexin V and Propidium Iodide (PI) staining assays. Additionally, ROS levels and PKC phosphorylation were also evaluated. In silico analysis has revealed that SEL is associated with ten genes linked to different cancer types. Specifically, SEL was most cytotoxic to neuronal pheochromocytoma, triple-negative human epithelial breast cancer cells, and ER+ and PR+ breast cancer cells. Furthermore, it was observed that this cell death occurred through ROS-independent apoptosis pathways. In addition, SEL was found to inhibit the phosphorylation of PKC, which may contribute to cell death. SEL induces apoptosis in breast cancer cells independently of reactive oxygen species and inhibits the phosphorylation of protein kinase C, which merits further exploration.

Osteopontin: A Key Multifaceted Regulator in Tumor Progression and Immunomodulation

The tumor microenvironment (TME) is composed of various cellular components such as tumor cells, stromal cells including fibroblasts, adipocytes, mast cells, lymphatic vascular cells and infiltrating immune cells, macrophages, dendritic cells and lymphocytes. The intricate interplay between these cells influences tumor growth, metastasis and therapy failure. Significant advancements in breast cancer therapy have resulted in a substantial decrease in mortality. However, existing cancer treatments frequently result in toxicity and nonspecific side effects. Therefore, improving targeted drug delivery and increasing the efficacy of drugs is crucial for enhancing treatment outcome and reducing the burden of toxicity. In this review, we have provided an overview of how tumor and stroma-derived osteopontin (OPN) plays a key role in regulating the oncogenic potential of various cancers including breast. Next, we dissected the signaling network by which OPN regulates tumor progression through interaction with selective integrins and CD44 receptors. This review addresses the latest advancements in the roles of splice variants of OPN in cancer progression and OPN-mediated tumor-stromal interaction, EMT, CSC enhancement, immunomodulation, metastasis, chemoresistance and metabolic reprogramming, and further suggests that OPN might be a potential therapeutic target and prognostic biomarker for the evolving landscape of cancer management.

Hypoxia-Inducible Factor 1-Alpha (HIF-1α): An Essential Regulator in Cellular Metabolic Control

The element that causes hypoxia when the von Hippel-Lindau (VHL) protein is not functioning is hypoxia-inducible factor 1-alpha (HIF-1α), which is the essential protein linked to cell control under hypoxia. Consequently, in situations where cells are oxygen-deficient, HIF-1α carries out a variety of essential functions. Citations to relevant literature support the notion that HIF-1α regulates the mitochondrial and glycolytic pathways, as well as the transition from the former to the latter. Cells with limited oxygen supply benefit from this change, which is especially beneficial for the inhibition of the mitochondrial electron transport chain and enhanced uptake of glucose and lactate. During hypoxic stress, HIF-1α also controls proline and glycolytic transporters such as lactate dehydrogenase A (LDHA) and glucose transporter 1 (GLUT1). These mechanisms help the cell return to homeostasis. Therefore, through metabolic change promoting adenosine triphosphate (ATP) synthesis and reducing reactive oxygen species (ROS) creation, HIF-1α may have a role in reducing oxidative stress in cells. This evidence, which describes the function of HIF-1α in many molecular pathways, further supports the notion that it is prognostic and that it contributes to hypoxic cell adaption. Understanding more about disorders, including inflammation, cancer, and ischemia, is possible because of HIF-1α's effect on metabolic changes. Gaining knowledge about the battle between metabolism, which is directed by HIF-1α, would help advance the research on pathophysiological situations involving dysregulated hypoxia and metabolism.

Thioredoxin system in colorectal cancer: Its role in carcinogenesis, disease progression, and response to treatment

The thioredoxin system is essential for many physiological processes, including the maintenance of redox signalling pathways. Alterations in the activity, expression and interactions with other signalling pathways can lead to protective or pathophysiological responses. Thioredoxin and thioredoxin reductase, the two main components of this system, are often overexpressed in cancer, including colorectal cancer. This overexpression is often linked with tumour progression and poor outcomes. This review discusses the role of the Trx system in driving colorectal carcinogenesis and disease progression, as well as the challenges of targeting this system. Additionally, the recent advancements in the development of novel and effective thioredoxin inhibitors for colorectal cancer are also explored.

Potential role of molecular hydrogen therapy on oxidative stress and redox signaling in chronic kidney disease

Oxidative stress plays a key role in chronic kidney disease (CKD) development and progression, inducing kidney cell damage, inflammation, and fibrosis. However, effective therapeutic interventions to slow down CKD advancement are currently lacking. The multifaceted pharmacological effects of molecular hydrogen (H2) have made it a promising therapeutic avenue. H2 is capable of capturing harmful •OH and ONOO- while maintaining the crucial reactive oxygen species (ROS) involved in cellular signaling. The NRF2-KEAP1 system, which manages cell redox balance, could be used to treat CKD. H2 activates this pathway, fortifying antioxidant defenses and scavenging ROS to counteract oxidative stress. H2 can improve NRF2 signaling by using the Wnt/β-catenin pathway and indirectly activate NRF2-KEAP1 in mitochondria. Additionally, H2 modulates NF-κB activity by regulating cellular redox status, inhibiting MAPK pathways, and maintaining Trx levels. Treatment with H2 also attenuates HIF signaling by neutralizing ROS while indirectly bolstering HIF-1α function. Furthermore, H2 affects FOXO factors and enhances the activity of antioxidant enzymes. Despite the encouraging results of bench studies, clinical trials are still limited and require further investigation. The focus of this review is on hydrogen's role in treating renal diseases, with a specific focus on oxidative stress and redox signaling regulation, and it discusses its potential clinical applications.

Seedless black Vitis vinifera polyphenols suppress hepatocellular carcinoma in vitro and in vivo by targeting apoptosis, cancer stem cells, and proliferation

Hepatocellular carcinoma (HCC) is an aggressive tumor and one of the most challenging cancers to treat. Here, we evaluated the in vitro and in vivo ameliorating impacts of seedless black Vitis vinifera (VV) polyphenols on HCC. Following the preparation of the VV crude extract (VVCE) from seedless VV (pulp and skin), three fractions (VVF1, VVF2, and VVF3) were prepared. The anticancer potencies of the prepared fractions, compared to 5-FU, were assessed against HepG2 and Huh7 cells. In addition, the effects of these fractions on p-dimethylaminoazobenzene-induced HCC in mice were evaluated. The predicted impacts of selected phenolic constituents of VV fractions on the activity of essential HCC-associated enzymes (NADPH oxidase "NADPH-NOX2", histone deacetylase 1 "HDAC1", and sepiapterin reductase "SepR") were analyzed using molecular docking. The results showed that VVCE and its fractions induced apoptosis and collapsed CD133+ stem cells in the studied cancer cell lines with an efficiency greater than 5-FU. VVF1 and VVF2 exhibited the most effective anticancer fractions in vitro; therefore, we evaluated their influences in mice. VVF1 and VVF2 improved liver morphology and function, induced apoptosis, and lowered the fold expression of various crucial genes that regulate cancer stem cells and other vital pathways for HCC progression. For most of the examined parameters, VVF1 and VVF2 had higher potency than 5-FU, and VVF1 showed more efficiency than VVF2. The selected phenolic compounds displayed competitive inhibitory action on NADPH-NOX2, HDAC1, and SepR. In conclusion, these findings declare that VV polyphenolic fractions, particularly VVF1, could be promising safe anti-HCC agents.

Understanding the Significance of Hypoxia-Inducible Factors (HIFs) in Glioblastoma: A Systematic Review

BACKGROUND

The study aims to investigate the role of hypoxia-inducible factors (HIFs) in the development, progression, and therapeutic potential of glioblastomas.

METHODOLOGY

The study, following PRISMA guidelines, systematically examined hypoxia and HIFs in glioblastoma using MEDLINE (PubMed), Web of Science, and Scopus. A total of 104 relevant studies underwent data extraction.

RESULTS

Among the 104 studies, global contributions were diverse, with China leading at 23.1%. The most productive year was 2019, accounting for 11.5%. Hypoxia-inducible factor 1 alpha (HIF1α) was frequently studied, followed by hypoxia-inducible factor 2 alpha (HIF2α), osteopontin, and cavolin-1. Commonly associated factors and pathways include glucose transporter 1 (GLUT1) and glucose transporter 3 (GLUT3) receptors, vascular endothelial growth factor (VEGF), phosphoinositide 3-kinase (PI3K)-Akt-mechanistic target of rapamycin (mTOR) pathway, and reactive oxygen species (ROS). HIF expression correlates with various glioblastoma hallmarks, including progression, survival, neovascularization, glucose metabolism, migration, and invasion.

CONCLUSION

Overcoming challenges such as treatment resistance and the absence of biomarkers is critical for the effective integration of HIF-related therapies into the treatment of glioblastoma with the aim of optimizing patient outcomes.

Hypoxia: Intriguing Feature in Cancer Cell Biology

Hypoxia, a key aspect of the tumor microenvironment, plays a vital role in cell proliferation, angiogenesis, metabolism, and the immune response within tumors. These factors collectively promote tumor advancement, aggressiveness, metastasis and result in a poor prognosis. Hypoxia inducible factor 1α (HIF-1α), activated under low oxygen conditions, mediates many of these effects by altering drug target expression, metabolic regulation, and oxygen consumption. These changes promote cancer cell growth and survival. Hypoxic tumor cells develop aggressive traits and resistance to chemotherapy and radiotherapy, leading to increased mortality. Targeting hypoxic tumor offers a potential solution to overcome the challenges posed by tumor heterogeneity and can be used in designing diagnostic and therapeutic nanocarriers for various solid cancers. This concept provides an overview of the intricate relationship between hypoxia and the tumor microenvironment, highlighting its potential as a promising tool for cancer therapies. The article explores the development of hypoxia in cancer cells and its role in cancer progression, along with the latest advancements in hypoxia-triggered cancer treatment.

Crosstalk between hypoxia-induced pyroptosis and immune escape in cancer: From mechanisms to therapy

Pyroptosis can be triggered through both canonical and non-canonical inflammasome pathways, involving the cleavage of gasdermin (GSDM) protein family members, like GSDMD and GSDME. The impact of pyroptosis on tumors is nuanced, because its role in regulating cancer progression and anti-tumor immunity may vary depending on the tumor type, stage, location, and immune status. However, pyroptosis cannot be simply categorized as promoting or inhibiting tumors based solely on whether it is acute or chronic in nature. The interplay between pyroptosis and cancer is intricate, with some evidence suggesting that chronic pyroptosis may facilitate tumor growth, while the acute induction of pyroptosis could stimulate anti-cancer immune responses. Tumor hypoxia activates hypoxia inducible factor (HIF) signaling to modulate pyroptosis and immune checkpoint expression. Targeting this hypoxia-pyroptosis-immune escape axis could be a promising therapeutic strategy. This review highlights the complex crosstalk between hypoxia, pyroptosis, and immune evasion in the TME.

The synthetic cannabinoid 5-fluoro ABICA upregulates angiogenic markers and stimulates tube formation in human brain microvascular endothelial cells

Objective

Synthetic cannabinoids (SCs), a class of psychoactive compounds emulating the effects of natural cannabis, have prompted addiction and psychosis concerns. However, recent research has suggested potential pharmacological applications, particularly in brain angiogenesis-an essential physiological process for growth, repair, and tissue maintenance, in which new blood vasculature is formed from existing vasculature. This study explored the in vitro ability of the SC 5-fluoro ABICA to enhance new blood formation processes in human brain microvascular endothelial cells (HBMECs).

Methods

HBMECs were treated with various concentrations of 5-fluoro ABICA (1 μM, 0.1 μM, 0.01 μM, 0.001 μM, and 0.0001 μM). A comprehensive analysis was conducted, including MTT assays indicating cell viability, wound healing assays indicating migration ability, and tube formation assays indicating the angiogenesis potential of endothelial cells. Additionally, mRNA expression and protein levels of specific pro-angiogenic factors were measured, and the phosphorylation levels of glycogen synthase kinase-3β were detected in treated HBMECs through ELISA, real-time PCR, and western blotting.

Results

Treatment with 5-fluoro ABICA effectively stimulated proliferation, migration, and tube formation in HBMECs in a dose-dependent manner; markedly increased the expression of pro-angiogenic factors; and upregulated levels of phosphorylated-GSK-3β.

Conclusion

Our findings demonstrate that 5-fluoro ABICA stimulates angiogenesis in endothelial cells, thus potentially offering therapeutic options for diseases associated with angiogenesis. However, further research is needed to fully understand the molecular mechanism of 5-fluoro ABICA in angiogenesis, including ethical considerations regarding its use in medical research.

Molecular Mechanisms of Neuroprotection after the Intermittent Exposures of Hypercapnic Hypoxia

The review introduces the stages of formation and experimental confirmation of the hypothesis regarding the mutual potentiation of neuroprotective effects of hypoxia and hypercapnia during their combined influence (hypercapnic hypoxia). The main focus is on the mechanisms and signaling pathways involved in the formation of ischemic tolerance in the brain during intermittent hypercapnic hypoxia. Importantly, the combined effect of hypoxia and hypercapnia exerts a more pronounced neuroprotective effect compared to their separate application. Some signaling systems are associated with the predominance of the hypoxic stimulus (HIF-1α, A1 receptors), while others (NF-κB, antioxidant activity, inhibition of apoptosis, maintenance of selective blood-brain barrier permeability) are mainly modulated by hypercapnia. Most of the molecular and cellular mechanisms involved in the formation of brain tolerance to ischemia are due to the contribution of both excess carbon dioxide and oxygen deficiency (ATP-dependent potassium channels, chaperones, endoplasmic reticulum stress, mitochondrial metabolism reprogramming). Overall, experimental studies indicate the dominance of hypercapnia in the neuroprotective effect of its combined action with hypoxia. Recent clinical studies have demonstrated the effectiveness of hypercapnic-hypoxic training in the treatment of childhood cerebral palsy and diabetic polyneuropathy in children. Combining hypercapnic hypoxia with pharmacological modulators of neuro/cardio/cytoprotection signaling pathways is likely to be promising for translating experimental research into clinical medicine.

PHA-665752's Antigrowth and Proapoptotic Effects on HSC-3 Human Oral Cancer Cells

c-Met is a tyrosine-kinase receptor, and its aberrant activation plays critical roles in tumorigenesis, invasion, and metastatic spread in many human tumors. PHA-665752 (PHA) is an inhibitor of c-Met and has antitumor effects on many hematological malignancies and solid cancers. However, the activation and expression of c-Met and its role and the antitumor effect of PHA on human oral squamous cell carcinoma (OSCC) cells remain unclear. Here, we investigated the activation and expression of c-Met and the effects of PHA on the growth of a highly tumorigenic HSC-3 human OSCC cell line with high c-Met phosphorylation and expression. Of note, c-Met was highly expressed and phosphorylated on Y1234/1235 in HSC-3 cells, and PHA treatment significantly suppressed the growth and induced apoptosis of these cells. Moreover, PHA that inhibited the phosphorylation (activation) of c-Met further caused the reduced phosphorylation and expression levels of Src, protein kinase B (PKB), mammalian target of rapamycin (mTtor), and myeloid cell leukemia-1 (Mcl-1) in HSC-3 cells. In addition, the antiangiogenic property of PHA in HSC-3 cells was shown, as evidenced by the drug's suppressive effect on the expression of hypoxia-inducible factor-1α (HIF-1α), a critical tumor angiogenic transcription factor. Importantly, genetic ablation of c-Met caused the reduced growth of HSC-3 cells and decreased Src phosphorylation and HIF-1α expression. Together, these results demonstrate that c-Met is highly activated in HSC-3 human oral cancer cells, and PHA exhibits strong antigrowth, proapoptotic, and antiangiogenic effects on these cells, which are mediated through regulation of the phosphorylation and expression of multiple targets, including c-Met, Src, PKB, mTOR, Mcl-1, and HIF-1α.

Use of oxygen-loaded nanobubbles to improve tissue oxygenation: Bone-relevant mechanisms of action and effects on osteoclast differentiation

Gas-loaded nanobubbles have potential as a method of oxygen delivery to increase tumour oxygenation and therapeutically alleviate tumour hypoxia. However, the mechanism(s) whereby oxygen-loaded nanobubbles increase tumour oxygenation are unknown; with their calculated oxygen-carrying capacity being insufficient to explain this effect. Intra-tumoural hypoxia is a prime therapeutic target, at least partly due to hypoxia-dependent stimulation of the formation and function of bone-resorbing osteoclasts which establish metastatic cells in bone. This study aims to investigate potential mechanism(s) of oxygen delivery and in particular the possible use of oxygen-loaded nanobubbles in preventing bone metastasis via effects on osteoclasts. Lecithin-based nanobubbles preferentially interacted with phagocytic cells (monocytes, osteoclasts) via a combination of lipid transfer, clathrin-dependent endocytosis and phagocytosis. This interaction caused general suppression of osteoclast differentiation via inhibition of cell fusion. Additionally, repeat exposure to oxygen-loaded nanobubbles inhibited osteoclast formation to a greater extent than nitrogen-loaded nanobubbles. This gas-dependent effect was driven by differential effects on the fusion of mononuclear precursor cells to form pre-osteoclasts, partly due to elevated potentiation of RANKL-induced ROS by nitrogen-loaded nanobubbles. Our findings suggest that oxygen-loaded nanobubbles could represent a promising therapeutic strategy for cancer therapy; reducing osteoclast formation and therefore bone metastasis via preferential interaction with monocytes/macrophages within the tumour and bone microenvironment, in addition to known effects of directly improving tumour oxygenation.

Therapeutic Targeting of Hypoxia-Inducible Factors in Cancer

In the realm of cancer therapeutics, targeting the hypoxia-inducible factor (HIF) pathway has emerged as a promising strategy. This study delves into the intricate web of HIF-associated mechanisms, exploring avenues for future anticancer therapies. Framing the investigation within the broader context of cancer progression and hypoxia response, this article aims to decipher the pivotal role played by HIF in regulating genes influencing angiogenesis, cell proliferation, and glucose metabolism. Employing diverse approaches such as HIF inhibitors, anti-angiogenic therapies, and hypoxia-activated prodrugs, the research methodologically intervenes at different nodes of the HIF pathway. Findings showcase the efficacy of agents like EZN-2968, Minnelide, and Acriflavine in modulating HIF-1α protein synthesis and destabilizing HIF-1, providing preliminary proof of HIF-1α mRNA modulation and antitumor activity. However, challenges, including toxicity, necessitate continued exploration and development, as exemplified by ongoing clinical trials. This article concludes by emphasizing the potential of targeted HIF therapies in disrupting cancer-related signaling pathways.

β-Caryophyllene Inhibits Endothelial Tube Formation by Modulating the Secretome of Hypoxic Lung Cancer Cells-Possible Role of VEGF Downregulation

β-Caryophyllene (BCP), a bicyclic sesquiterpene that is a component of the essential oils of various spice and food plants, has been described as a selective CB2 cannabinoid receptor agonist. In the present study, the effect of BCP on angiogenesis was investigated. It was found that conditioned media (CM) from BCP-treated hypoxic A549 lung cancer cells exhibited a concentration-dependent inhibitory effect on human umbilical vein endothelial cell (HUVEC) tube formation induced by CM from vehicle-treated hypoxic A549 cells. There was an associated concentration-dependent decrease in the proangiogenic factor vascular endothelial growth factor (VEGF) in the CM, with both BCP inhibitory effects (tube formation, VEGF secretion) being CB2 receptor-dependent. A reduction of the transcription factor hypoxia-inducible factor 1α (HIF-1α) was furthermore detected. The antiangiogenic and VEGF-lowering properties of BCP were confirmed when CM from another lung cancer cell line, H358, were tested. When directly exposed to HUVECs, BCP showed no significant effect on tube formation, but at 10 µM, impaired VEGF receptor 2 (VEGFR2) phosphorylation triggered by recombinant VEGF in a CB2 receptor-independent manner. In summary, BCP has a dual antiangiogenic effect on HUVECs, manifested in the inhibition of tube formation through modulation of the tumor cell secretome and additionally in the inhibition of VEGF-induced VEGFR2 activation. Because the CB2 agonist has no psychoactive properties, BCP should continue to be evaluated preclinically for further antitumor effects.

CRABP2 affects chemotherapy resistance of ovarian cancer by regulating the expression of HIF1α

Ovarian cancer is the most lethal malignancy among gynecologic cancers, and primary and secondary chemotherapy resistance is one of the important reasons for poor prognosis of ovarian cancer patients. However, the specifics of resistance to chemotherapy in ovarian cancer remain unclear. Herein, we find that the expression level of cellular retinoic acid binding protein 2 (CRABP2) is up-regulated in drug-resistant ovarian cancer tissues and cell lines, and the expression levels of CRABP2 in epithelial ovarian cancer tissues are closely related to tumor clinical stage and patients' prognosis, suggesting that CRABP2 plays an important role in the progression of ovarian cancer and the corresponding ability of tumor to chemotherapy. With the in-depth study, we demonstrates that CRABP2 is related to the high metabolic activity in drug-resistant cells, and all-trans retinoic acid exacerbates this activity. Further molecular mechanism exploration experiments show that CRABP2 not only up-regulates the expression level of HIF1α, but also increases the localization of HIF1α in the nucleus. In drug-resistant ovarian cancer cells, knocking down HIF1α can block the resistance of CRABP2 to chemotherapy drugs in ovarian cancer cells. Taken together, our findings suggest for the first time that CRABP2 affects chemotherapy resistance of ovarian cancer by regulating the expression of HIF1α. This study provides a possible molecular mechanism for drug resistance and a possible molecular target for clinical treatment of ovarian cancer.

Colorectal Cancer in Correlation With Clinicopathological Variables: The Effects of Hypoxia-Inducible Factor-1 Alfa or the InterLeukin-33 and Vascular Endothelial Growth Factor?

Background The hypoxia-inducible factor-1 alpha (HIF-1α) is believed to control angiogenesis and metabolism by upregulating hypoxia-induced genes, such as the interLeukin-33 (IL-33) gene and vascular endothelial growth factor (VEGF) gene. The study aimed to study the HIF-1α and its two hypoxia pathway genes; IL-33 and VEGF, together with the angiogenesis and correlate them with some prognostic clinicopathological features, separately and in combination to assess their dependency. Methodology This study included 87 colorectal cancer (CRC) cases, diagnosed between January 2019 and December 2022. Different prognostic clinicopathological features were examined and tissue microarray (TMA) slides were designed to carry out IHC for IL-33 and VEGF scoring in tumor cells, in addition to qualitative interpretation of VEGF expression in tumor vessels. Molecular analysis was performed for HIF-1α and all data were correlated to the clinicopathological features, separately and collectively, to assess the dependency of these factors. Results No statistical correlation could be seen among the IL-33, VEGF, and prognostic clinicopathological features. Whereas analysis of the HIF-1α alone showed significantly high mean expression in patients with distance metastasis and was increased with the increased involvement of the lymph nodes (LNs). However, when the HIF 1-α expression was correlated with the clinicopathological characteristics on the bases of VEGF and IL-33 expressions the significant association with metastasis disappeared in tumor cells and appeared only with the endothelium of the tumor angiogenesis. Moreover, the results conflicted with the LNs involvement. Conclusions These findings may suggest a role of HIF 1-α in the downstream regulation of biomarkers other than the VEGF and IL-33, which needs to uncover pathways and novel factors regulated by the HIF 1-α for the proinflammation and angiogenesis in malignancy.

Hypoxia-induced signaling in the cardiovascular system: pathogenesis and therapeutic targets

Hypoxia, characterized by reduced oxygen concentration, is a significant stressor that affects the survival of aerobic species and plays a prominent role in cardiovascular diseases. From the research history and milestone events related to hypoxia in cardiovascular development and diseases, The "hypoxia-inducible factors (HIFs) switch" can be observed from both temporal and spatial perspectives, encompassing the occurrence and progression of hypoxia (gradual decline in oxygen concentration), the acute and chronic manifestations of hypoxia, and the geographical characteristics of hypoxia (natural selection at high altitudes). Furthermore, hypoxia signaling pathways are associated with natural rhythms, such as diurnal and hibernation processes. In addition to innate factors and natural selection, it has been found that epigenetics, as a postnatal factor, profoundly influences the hypoxic response and progression within the cardiovascular system. Within this intricate process, interactions between different tissues and organs within the cardiovascular system and other systems in the context of hypoxia signaling pathways have been established. Thus, it is the time to summarize and to construct a multi-level regulatory framework of hypoxia signaling and mechanisms in cardiovascular diseases for developing more therapeutic targets and make reasonable advancements in clinical research, including FDA-approved drugs and ongoing clinical trials, to guide future clinical practice in the field of hypoxia signaling in cardiovascular diseases.

3-deazaneplanocin A, a histone methyltransferase inhibitor, improved the chemoresistance induced under hypoxia in melanoma cells

One of common characteristics of solid tumors is low O2 level, so-called hypoxia, which plays a critical role in chemoresistance. Epigenetic mechanism such as DNA methylation and histone modification is involved in cancer development and progression. There is ample evidence that epigenetic drugs reversed acquired chemoresistance in cancer cells under normal O2 level, normoxia. However, it remains unknown whether epigenetic drugs improve acquired chemoresistance under hypoxia. The aim of our study was to investigate whether epigenetic drugs can improve the chemoresistance induced under hypoxia in cancer cells. In murine melanoma B16-BL6 (B16) cells, the culture under hypoxia, 1%O2 caused the elevated expression of hypoxia-inducible factor-1α (HIF-1α) and its target genes. The chemoresistance to 7-ethyl-10-hydroxycamptothecin (SN-38, the active metabolite of irinotecan) was also acquired under hypoxia in B16 cells. In addition, as epigenetic mechanisms, the protein expression of the enhancer of zeste homolog 2 (EZH2), histone methyltransferase and its target histone H3 trimethylation at lysine 27 (H3K27Me3) level increased under hypoxia. The induction of H3K27Me3 under hypoxia was suppressed by EZH2 siRNA and 3-deazaneplanocin A (DZNep), an EZH2 inhibitor. Furthermore, both EZH2 siRNA and DZNep significantly reduced the cell viability after SN-38 treatment and improved the chemoresistance to SN-38 under hypoxia. These results indicated that the chemoresistance to SN-38 under hypoxia would arise from epigenetic mechanism, H3K27Me3 elevation due to EZH2 induction. In conclusion, a histone methyltransferase EZH2 inhibitor, DZNep was capable of tackling acquired chemoresistance via the suppression of histone methylation induced under hypoxic tumor microenvironment.

Tumor microenvironment-induced tumor cell plasticity: relationship with hypoxic stress and impact on tumor resistance

The role of tumor interaction with stromal components during carcinogenesis is crucial for the design of efficient cancer treatment approaches. It is widely admitted that tumor hypoxic stress is associated with tumor aggressiveness and thus impacts susceptibility and resistance to different types of treatments. Notable biological processes that hypoxia functions in include its regulation of tumor heterogeneity and plasticity. While hypoxia has been reported as a major player in tumor survival and dissemination regulation, the significance of hypoxia inducible factors in cancer stem cell development remains poorly understood. Several reports indicate that the emergence of cancer stem cells in addition to their phenotype and function within a hypoxic tumor microenvironment impacts cancer progression. In this respect, evidence showed that cancer stem cells are key elements of intratumoral heterogeneity and more importantly are responsible for tumor relapse and escape to treatments. This paper briefly reviews our current knowledge of the interaction between tumor hypoxic stress and its role in stemness acquisition and maintenance. Our review extensively covers the influence of hypoxia on the formation and maintenance of cancer stem cells and discusses the potential of targeting hypoxia-induced alterations in the expression and function of the so far known stem cell markers in cancer therapy approaches. We believe that a better and integrated understanding of the effect of hypoxia on stemness during carcinogenesis might lead to new strategies for exploiting hypoxia-associated pathways and their targeting in the clinical setting in order to overcome resistance mechanisms. More importantly, at the present time, efforts are oriented towards the design of innovative therapeutical approaches that specifically target cancer stem cells.

CDCA8 promotes bladder cancer survival by stabilizing HIF1α expression under hypoxia

Hypoxia is an essential hallmark of solid tumors and HIF1α is a central regulator of tumor cell adaptation and survival in the hypoxic environment. In this study, we explored the biological functions of cell cycle division-related gene 8 (CDCA8) in bladder cancer (BCa) cells in the hypoxic settings. Specifically, we found that CDCA8 was significantly upregulated in BCa cell lines and clinical samples and its expression was positively correlated with advanced BCa stage, grade, and poor overall survival (OS). The expression of CDCA8 proteins was required for BCa cells to survive in the hypoxic condition. Mechanistically, CDCA8 stabilizes HIF1α by competing with PTEN for AKT binding, consequently leading to PTEN displacement and activation of the AKT/GSK3β signaling cascade that stimulates HIF1α protein stability. Significantly, HIF1α proteins bind to CDCA8 promoter for transcriptional activation, forming a positive-feedback loop to sustain BCa tumor cells under oxygen-deficient environment. Together, we defined CDCA8 as a key regulator for BCa cells to sense and prevail oxygen deprivation and as a novel BCa therapeutic target.

Antiangiogenic Action of JZL184 on Endothelial Cells via Inhibition of VEGF Expression in Hypoxic Lung Cancer Cells

JZL184, an inhibitor of monoacylglycerol lipase (MAGL) and thus of the degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG), mediates various anticancer effects in preclinical studies. However, studies on the effect of this or other MAGL inhibitors under hypoxia, an important factor in tumor biology and response to cancer therapy, have not yet been performed in cancer cells. In the present study, the impact of the conditioned media (CM) of A549 and H358 lung cancer cells incubated with JZL184 under hypoxic conditions on the angiogenic properties of human umbilical vein endothelial cells (HUVECs) was investigated. Treatment of HUVECs with CM derived from cancer cells cultured for 48 h under hypoxic conditions was associated with a substantial increase in migration and tube formation compared with unconditioned medium, which was inhibited when cancer cells were incubated with JZL184. In this process, JZL184 led to a significant increase in 2-AG levels in both cell lines. Analysis of a panel of proangiogenic factors revealed inhibition of hypoxia-induced vascular endothelial growth factor (VEGF) expression by JZL184. Antiangiogenic and VEGF-lowering effects were also demonstrated for the MAGL inhibitor MJN110. Receptor antagonist experiments suggest partial involvement of the cannabinoid receptors CB1 and CB2 in the antiangiogenic and VEGF-lowering effects induced by JZL184. The functional importance of VEGF for angiogenesis in the selected system is supported by observations showing inhibition of VEGF receptor 2 (VEGFR2) phosphorylation in HUVECs by CM from hypoxic cancer cells treated with JZL184 or when hypoxic cancer cell-derived CM was spiked with a neutralizing VEGF antibody. On the other hand, JZL184 did not exert a direct effect on VEGFR2 activation induced by recombinant VEGF, so there seems to be no downstream effect on already released VEGF. In conclusion, these results reveal a novel mechanism of antiangiogenic action of JZL184 under conditions of hypoxic tumor-endothelial communication.

Phytochemicals targeting glycolysis in colorectal cancer therapy: effects and mechanisms of action

Colorectal cancer (CRC) is the third most common malignant tumor in the world, and it is prone to recurrence and metastasis during treatment. Aerobic glycolysis is one of the main characteristics of tumor cell metabolism in CRC. Tumor cells rely on glycolysis to rapidly consume glucose and to obtain more lactate and intermediate macromolecular products so as to maintain growth and proliferation. The regulation of the CRC glycolysis pathway is closely associated with several signal transduction pathways and transcription factors including phosphatidylinositol 3-kinases/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR), adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), hypoxia-inducible factor-1 (HIF-1), myc, and p53. Targeting the glycolytic pathway has become one of the key research aspects in CRC therapy. Many phytochemicals were shown to exert anti-CRC activity by targeting the glycolytic pathway. Here, we review the effects and mechanisms of phytochemicals on CRC glycolytic pathways, providing a new method of drug development.

Atherosclerosis, Diabetes Mellitus, and Cancer: Common Epidemiology, Shared Mechanisms, and Future Management

The involvement of cardiovascular disease in cancer onset and development represents a contemporary interest in basic science. It has been recognized, from the most recent research, that metabolic syndrome-related conditions, ranging from atherosclerosis to diabetes, elicit many pathways regulating lipid metabolism and lipid signaling that are also linked to the same framework of multiple potential mechanisms for inducing cancer. Otherwise, dyslipidemia and endothelial cell dysfunction in atherosclerosis may present common or even interdependent changes, similar to oncogenic molecules elevated in many forms of cancer. However, whether endothelial cell dysfunction in atherosclerotic disease provides signals that promote the pre-clinical onset and proliferation of malignant cells is an issue that requires further understanding, even though more questions are presented with every answer. Here, we highlight the molecular mechanisms that point to a causal link between lipid metabolism and glucose homeostasis in metabolic syndrome-related atherosclerotic disease with the development of cancer. The knowledge of these breakthrough mechanisms may pave the way for the application of new therapeutic targets and for implementing interventions in clinical practice.

Uncovering the Secrets of Prostate Cancer's Radiotherapy Resistance: Advances in Mechanism Research

Prostate cancer (PCa) is a critical global public health issue with its incidence on the rise. Radiation therapy holds a primary role in PCa treatment; however, radiation resistance has become increasingly challenging as we uncover more about PCa's pathogenesis. Our review aims to investigate the multifaceted mechanisms underlying radiation therapy resistance in PCa. Specifically, we will examine how various factors, such as cell cycle regulation, DNA damage repair, hypoxic conditions, oxidative stress, testosterone levels, epithelial-mesenchymal transition, and tumor stem cells, contribute to radiation therapy resistance. By exploring these mechanisms, we hope to offer new insights and directions towards overcoming the challenges of radiation therapy resistance in PCa. This can also provide a theoretical basis for the clinical application of novel ultra-high-dose-rate (FLASH) radiotherapy in the era of PCa.

Micro RNAs and Circular RNAs in Different Forms of Otitis Media

The aim of this comprehensive review was to present the current knowledge on the role of microRNAs (miRNAs) in acute, recurrent, and chronic forms of otitis media. Special attention was focused on cholesteatoma of the middle ear. MicroRNAs modulate gene expression, which, in turn, influences the development and likelihood of the recurrence of acute and aggressive chronic middle ear inflammatory processes. Moreover, this study discusses the modulating role of a specific subgroup of noncoding RNA, circular RNA (circRNA). Recognizing the precise potential pathways and the mechanisms of their function may contribute to a better understanding of the molecular bases of middle ear diseases and identifying novel methods for treating this demanding pathology. Articles published between 2009 and 2022 were used in this analysis. In this review, we provide a complete overview of the latest progress in identifying the role and mechanisms of particular miRNAs and circRNAs in acute, recurrent and chronic forms of otitis media.

Exosomal cargos-mediated metabolic reprogramming in tumor microenvironment

Metabolic reprogramming is one of the hallmarks of cancer. As nutrients are scarce in the tumor microenvironment (TME), tumor cells adopt multiple metabolic adaptations to meet their growth requirements. Metabolic reprogramming is not only present in tumor cells, but exosomal cargos mediates intercellular communication between tumor cells and non-tumor cells in the TME, inducing metabolic remodeling to create an outpost of microvascular enrichment and immune escape. Here, we highlight the composition and characteristics of TME, meanwhile summarize the components of exosomal cargos and their corresponding sorting mode. Functionally, these exosomal cargos-mediated metabolic reprogramming improves the "soil" for tumor growth and metastasis. Moreover, we discuss the abnormal tumor metabolism targeted by exosomal cargos and its potential antitumor therapy. In conclusion, this review updates the current role of exosomal cargos in TME metabolic reprogramming and enriches the future application scenarios of exosomes.

Changes in serum hypoxia-inducible factor-1α and erythropoietin in allergic rhinitis patients: Correlation with the Th inflammatory profile and disease comorbidities

OBJECTIVES

The balance between proinflammatory IFN-γ Th1 vs. the anti-inflammatory allergy-mediating IL-4-heralded Th2 reactions is pivotal in IgE-mediated allergic rhinitis (AR). Hypoxia-Inducible Factor (HIF)-1α is inducible by hypoxia and various cytokines. HIF-1α activates different anti-pathogen and allergic immune cells. This cross-sectional study assessed the changes in serum HIF-1α and its dependent erythropoietin (EPO) levels among hospital-characterized AR patients. Type of the immune reaction, Th1 vs. Th2, was stratified based on the calculated IL-4/IFN-γ direct ratio, after being measured using specific ELISA assays.

METHODS

147 AR patients (83 males/64 females), and age-, BMI-, and gender-matched 24 healthy controls (13 males/11 females) were sequentially enrolled at ENT Unit, Prince Muteb General Hospital, Sakaka, Saudi Arabia. Measurement of serum parameters was carried out using specific ELISA assays.

RESULTS

Contrary to the majority of previous publications, all controls and the majority of patients (n = 137/147) exhibited naive Th0 immune response. IFN-γ and HIF-1α levels were greater in controls than in patients (168.9 ± 173.9 vs 108 ± 94.5 pg/mL; p<.012) and controls had a lower IL-4/IFN-ratio (2.439 ± 0.897 vs 3.33 ± 1.19; p<.001) than patients. The HIF-1α results disagree with earlier studies. Due to the wide inter-individual variations, serum IL-4 and EPO levels in controls were non-significantly higher than patients. Lower IL-4 levels (267.3 ± 79.95 vs 353.4 ± 320.6 pg/mL; p < .01) and the ratio (2.814 ± 1.335 vs 3.431 ± 1.137; p < .05) were associated with obstructive sleep apnea. Lower ratio was also associated with inferior turbinate hypertrophy (3.051 ± 1.026 vs 3.787 ± 1.310; p < .001). EPO and IL-4 levels were lower in patients with deviated nasal septum (66.69 ± 26.81 vs 84.24 ± 61.5 pg/mL; p < .021; and 299.5 ± 137.3 vs 391.1 ± 52.780 pg/mL; p < .001, respectively). Significant correlations were found between the recorded levels and AR comorbidities.

CONCLUSION

These results confirmed a pathogenic implication for HIF-1α and IFN-γ in AR that warranted future bigger and longitudinal studies.