The impact of O2 availability on human cancer

HIF2α activation and mitochondrial deficit due to iron chelation cause retinal atrophy

Iron accumulation causes cell death and disrupts tissue functions, which necessitates chelation therapy to reduce iron overload. However, clinical utilization of deferoxamine (DFO), an iron chelator, has been documented to give rise to systemic adverse effects, including ocular toxicity. This study provided the pathogenic and molecular basis for DFO-related retinopathy and identified retinal pigment epithelium (RPE) as the target tissue in DFO-related retinopathy. Our modeling demonstrated the susceptibility of RPE to DFO compared with the neuroretina. Intriguingly, we established upregulation of hypoxia inducible factor (HIF) 2α and mitochondrial deficit as the most prominent pathogenesis underlying the RPE atrophy. Moreover, suppressing hyperactivity of HIF2α and preserving mitochondrial dysfunction by α-ketoglutarate (AKG) protects the RPE against lesions both in vitro and in vivo. This supported our observation that AKG supplementation alleviates visual impairment in a patient undergoing DFO-chelation therapy. Overall, our study established a significant role of iron deficiency in initiating DFO-related RPE atrophy. Inhibiting HIF2α and rescuing mitochondrial function by AKG protect RPE cells and can potentially ameliorate patients' visual function.

Profiles of Expression of SAV1 in Normoxia or Hypoxia Microenviroment are Associated with Breast Cancer Prognosis

BACKGROUND

In breast cancer (BC), hypoxia is associated with poor prognosis. Protein Salvador homolog 1 (SAV1) acts as a tumor suppressor and is downregulated in the cancer cells. However, there is limited data on the expression profile of SAV1 and its importance in BC. It has not been studied to evaluate this phenomenon in a hypoxic microenvironment yet.

AIM

This study aimed to investigate SAV1 expression profiles under normoxia and hypoxia, and the potential of SAV1 in BC prognosis.

METHODS

Gene and protein expression analyses were performed using Real-Time quantitative PCR (RT-qPCR) and immunocytochemistry (ICC), respectively, and in silico analyses were performed using The Cancer Genome Atlas (TCGA). The survival curves were constructed using KMplotter.

RESULTS

SAV1 expression was lower in BC samples and tumor cell lines than in normal samples. The SAV1 mRNA levels were reduced in hypoxic estrogen receptor positive (ER⁺) tumors, which were associated with a lower survival probability as compared to normoxic ER⁺ tumors. Furthermore, lower levels of SAV1 were found in advanced cancer stage samples, which are associated with worse survival curves and can be a risk factor for BC.

CONCLUSIONS

These data suggest a potential prognostic role of SAV1 in BC, with lower expressions associated with worse prognosis.

Tumor micronecrosis predicts poor prognosis of patients with hepatocellular carcinoma after liver transplantation

BACKGROUND

Tumor micronecrosis is a histopathological feature predicting poor prognosis in patients with hepatocellular carcinoma (HCC) who underwent liver resection. However, the role of tumor micronecrosis in liver transplantation remains unclear.

METHODS

We retrospectively reviewed patients with HCC who underwent liver transplantation between January 2015 and December 2021 at our center. We then classified them into micronecrosis(-) and micronecrosis(+) groups and compared their recurrence-free survival (RFS) and overall survival (OS). We identified independent prognostic factors using Cox regression analysis and calculated the area under the receiver operating characteristic curve (AUC) to evaluate the predictive value of RFS for patients with HCC after liver transplantation.

RESULTS

A total of 370 cases with evaluable histological sections were included. Patients of the micronecrosis(+) group had a significantly shorter RFS than those of the micronecrosis(-) group (P = 0.037). Shorter RFS and OS were observed in micronecrosis(+) patients without bridging treatments before liver transplantation (P = 0.002 and P = 0.007), while no differences were detected in those with preoperative antitumor therapies that could cause iatrogenic tumor necrosis. Tumor micronecrosis improved the AUC of Milan criteria (0.77-0.79), the model for end-stage liver disease score (0.70-0.76), and serum alpha-fetoprotein (0.63-0.71) for the prediction of prognosis after liver transplantation.

CONCLUSION

Patients with HCC with tumor micronecrosis suffer from a worse prognosis than those without this feature. Tumor micronecrosis can help predict RFS after liver transplantation. Therefore, patients with HCC with tumor micronecrosis should be treated with adjuvant therapy and closely followed after liver transplantation.

CLINICAL TRIALS REGISTRATION

Not Applicable.

MIF promotes cell invasion by the LRP1-uPAR interaction in pancreatic cancer cells

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is characterized by high aggressiveness and a hypoxic tumour microenvironment. Macrophage migration inhibitory factor (MIF) is a hypoxia-related pleiotropic cytokine that plays important roles in cancer. However, its role in PDAC progression has not been fully elucidated.

Methods

The clinical significance of MIF and hypoxia inducible factor 1 subunit alpha (HIF1A) in PDAC was analysed using immunohistochemical staining on PDAC tissues and data from KM-Plotter database. Spatial distribution of MIF and HIF1A gene expression was visualized by spatial transcriptomics in PDAC cell xenografts. To monitor the role of MIF in PDAC cell malignancy, immunostaining, lentivirus shRNA, migration assays, flow cytometry, transcriptomics and in vivo tumorigenicity were performed.

Results

The spatial distribution of MIF and HIF1A was highly correlated and that high MIF expression was associated with poor prognosis of PDAC patients. MIF knockdown impaired cell invasion, with a decrease in the expression of urokinase-type plasminogen activator receptor (uPAR). Although PLAUR transcript was not reduced, a uPAR endocytic receptor, low-density lipoprotein receptor-related protein 1 (LRP1), was upregulated at both the mRNA and protein levels after MIF knockdown. The LRP1 antagonist RAP restored uPAR expression and invasiveness. MIF attenuated the nuclear translocation of p53, a transcriptional regulator of LRP1. Furthermore, MIF downregulation blunted the growth of PDAC cell xenografts and inhibited cell proliferation under normoxia and hypoxia. Transcriptome analysis also provided evidence for the role of MIF in cancer-associated pathways.

Discussion

We demonstrate a novel link between the two pro-invasive agents MIF and uPAR and explain how MIF increases PDAC cell invasion capability. This finding provides a basis for therapeutic intervention of MIF in PDAC progression.

Effects of the exercise-inducible myokine irisin on proliferation and malignant properties of ovarian cancer cells through the HIF-1 α signaling pathway

Exercise has been shown to be associated with reduced risk and improving outcomes of several types of cancers. Irisin -a novel exercise-related myokine- has been proposed to exert beneficial effects in metabolic disorders including cancer. No previous studies have investigated whether irisin may regulate malignant characteristics of ovarian cancer cell lines. In the present study, we aimed to explore the effect of irisin on viability and proliferation of ovarian cancer cells which was examined by MTT assay. Then, we evaluated the migratory and invasive abilities of the cells via transwell assays. Moreover, the percentage of apoptosis induction was determined by flow cytometry. Furthermore, the mRNA expression level of genes related to the aerobic respiration (HIF-1α, c-Myc, LDHA, PDK1 and VEGF) was detected by real-time PCR. Our data revealed that irisin treatment significantly attenuated the proliferation, migration and invasion of ovarian cancer cells. Additionally, irisin induced apoptosis in ovarian cancer cells. We also observed that irisin regulated the expression of genes involved in aerobic respiration of ovarian cancer cells. Our results indicated that irisin may play a crucial role in inhibition of cell growth and malignant characteristics of ovarian cancer. These findings may open up avenues for future studies to identify the further therapeutic use of irisin in ovarian cancer management.

The Role of Hypoxia in Brain Tumor Immune Responses

Oxygen is a vital component of living cells. Low levels of oxygen in body tissues, known as hypoxia, can affect multiple cellular functions across a variety of cell types and are a hallmark of brain tumors. In the tumor microenvironment, abnormal vasculature and enhanced oxygen consumption by tumor cells induce broad hypoxia that affects not only tumor cell characteristics but also the antitumor immune system. Although some immune reactions require hypoxia, hypoxia generally negatively affects immunity. Hypoxia induces tumor cell invasion, cellular adaptations to hypoxia, and tumor cell radioresistance. In addition, hypoxia limits the efficacy of immunotherapy and hinders antitumor responses. Therefore, understanding the role of hypoxia in the brain tumor, which usually does not respond to immunotherapy alone is important for the development of effective anti-tumor therapies. In this review, we discuss recent evidence supporting the role of hypoxia in the context of brain tumors.

Updated perspective of EPAS1 and the role in pulmonary hypertension

Pulmonary hypertension (PH) is a group of syndromes characterized by irreversible vascular remodeling and persistent elevation of pulmonary vascular resistance and pressure, leading to ultimately right heart failure and even death. Current therapeutic strategies mainly focus on symptoms alleviation by stimulating pulmonary vessel dilation. Unfortunately, the mechanism and interventional management of vascular remodeling are still yet unrevealed. Hypoxia plays a central role in the pathogenesis of PH and numerous studies have shown the relationship between PH and hypoxia-inducible factors family. EPAS1, known as hypoxia-inducible factor-2 alpha (HIF-2α), functions as a transcription factor participating in various cellular pathways. However, the detailed mechanism of EPAS1 has not been fully and systematically described. This article exhibited a comprehensive summary of EPAS1 including the molecular structure, biological function and regulatory network in PH and other relevant cardiovascular diseases, and furthermore, provided theoretical reference for the potential novel target for future PH intervention.

Bioinformatics Analysis Identifies EPAS1 as a Novel Prognostic Marker Correlated with Immune Infiltration in Acute Myeloid Leukemia

EPAS1 plays an important role in the development and progression of multiple tumor types by interacting with a series of other molecules. However, the prognostic and diagnostic values of EPAS1 in acute myeloid leukemia (AML) remain unknown. Here, we systematically explored and clarified the potential functions of EPAS1 in AML using data from Xena Browser and TCGA database. The expression of EPAS1 was significantly lower in AML patients than that in healthy people. The GO, KEGG, GSEA, and GSVA were performed to explore the potential functions and signaling pathways. The survival analysis was conducted using Cox regression analysis and the Kaplan-Meier method. Immune cell infiltration was evaluated via single-sample GSEA (ssGSEA). The results of enrichment analyses suggested that low-EPAS1 expression was related to the initiation, development, and prognosis of AML. The immune microenvironment landscape in AML was described by ssGSEA. ROC analysis of EPAS1 showed high discrimination ability between AML patients and healthy people. Kaplan-Meier method indicated that low-EPAS1 expression correlated significantly with a poor overall survival. Multivariate Cox regression analysis revealed that both age and EPAS1 expression were independent prognostic factors in AML patients. Furthermore, the nomogram based on these two variables performed well in discrimination and calibration. In summary, our study may provide new insights into the molecular mechanisms underlying AML and demonstrate the diagnostic and prognostic value of EPAS1 in AML for the first time.

CRAC and SK Channels: Their Molecular Mechanisms Associated with Cancer Cell Development

Cancer represents a major health burden worldwide. Several molecular targets have been discovered alongside treatments with positive clinical outcomes. However, the reoccurrence of cancer due to therapy resistance remains the primary cause of mortality. Endeavors in pinpointing new markers as molecular targets in cancer therapy are highly desired. The significance of the co-regulation of Ca²⁺-permeating and Ca²⁺-regulated ion channels in cancer cell development, proliferation, and migration make them promising molecular targets in cancer therapy. In particular, the co-regulation of the Orai1 and SK3 channels has been well-studied in breast and colon cancer cells, where it finally leads to an invasion-metastasis cascade. Nevertheless, many questions remain unanswered, such as which key molecular components determine and regulate their interplay. To provide a solid foundation for a better understanding of this ion channel co-regulation in cancer, we first shed light on the physiological role of Ca²⁺ and how this ion is linked to carcinogenesis. Then, we highlight the structure/function relationship of Orai1 and SK3, both individually and in concert, their role in the development of different types of cancer, and aspects that are not yet known in this context.

Importance of lactate dehydrogenase (LDH) and monocarboxylate transporters (MCTs) in cancer cells

Background

In most regions, cancer ranks the second most frequent cause of death following cardiovascular disorders.

Aim

In this article, we review the various aspects of glycolysis with a focus on types of MCTs and the importance of lactate in cancer cells.

Results and Discussion

Metabolic changes are one of the first and most important alterations in cancer cells. Cancer cells use different pathways to survive, energy generation, growth, and proliferation compared to normal cells. The increase in glycolysis, which produces substances such as lactate and pyruvate, has an important role in metastases and invasion of cancer cells. Two important cellular proteins that play a role in the production and transport of lactate include lactate dehydrogenase and monocarboxylate transporters (MCTs). These molecules by their various isoforms and different tissue distribution help to escape the immune system and expansion of cancer cells under different conditions.

Hypoxia-immune-related microenvironment prognostic signature for osteosarcoma

Introduction: Increasing evidences have shown that hypoxia and the immune microenvironment play vital roles in the development of osteosarcoma. However, reliable gene signatures based on the combination of hypoxia and the immune status for prognostic prediction of osteosarcoma have so far not been identified. Methods: The individual hypoxia and immune status of osteosarcoma patients were identified with transcriptomic profiles of a training cohort from the TARGET database using ssGSEA and ESTIMATE algorithms, respectively. Lasso regression and stepwise Cox regression were performed to develop a hypoxia-immune-based gene signature. An independent cohort from the GEO database was used for external validation. Finally, a nomogram was constructed based on the gene signature and clinical features to improve the risk stratification and to quantify the risk assessment for individual patients. Results: Hypoxia and the immune status were significantly associated with the prognosis of osteosarcoma patients. Seven hypoxia- and immune-related genes (BNIP3, SLC38A5, SLC5A3, CKMT2, S100A3, CXCL11 and PGM1) were identified to be involved in our prognostic signature. In the training cohort, the prognostic signature discriminated high-risk patients with osteosarcoma. The hypoxia-immune-based gene signature proved to be a stable and predictive method as determined in different datasets and subgroups of patients. Furthermore, a nomogram based on the prognostic signature was generated to optimize the risk stratification and to quantify the risk assessment. Similar results were validated in an independent GEO cohort, confirming the stability and reliability of the prognostic signature. Conclusion: The hypoxia-immune-based prognostic signature might contribute to the optimization of risk stratification for survival and personalized management of osteosarcoma patients.

The evaluation expression of non-coding RNAs in response to HSV-G47∆ oncolytic virus infection in glioblastoma multiforme cancer stem cells

Glioblastoma multiforme is the most aggressive astrocytes brain tumor. Glioblastoma cancer stem cells and hypoxia conditions are well-known major obstacles in treatment. Studies have revealed that non-coding RNAs serve a critical role in glioblastoma progression, invasion, and resistance to chemo-radiotherapy. The present study examined the expression levels of microRNAs (in normoxic condition) and long non-coding RNAs (in normoxic and hypoxic conditions) in glioblastoma stem cells treated with the HSV-G47∆. The expression levels of 43 miRNAs and 8 lncRNAs isolated from U251-GBM-CSCs were analyzed using a miRCURY LNA custom PCR array and a quantitative PCR assay, respectively. The data revealed that out of 43 miRNAs that only were checked in normoxic condition, the only 8 miRNAs, including miR-7-1, miR-let-7b, miR-130a, miR-137, miR-200b, miR-221, miR-222, and miR-874, were markedly upregulated. The expression levels of lncRNAs, including LEF1 antisense RNA 1 (LEF1-AS1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), long intergenic non-protein coding RNA 470 (LINC00470), tumor suppressor candidate 7 (TUSC7), HOX transcript antisense RNA (HOTAIR), nuclear paraspeckle assembly transcript 1 (NEAT1), and X inactive specific transcript (XIST), were markedly downregulated in the hypoxic microenvironment, and H19-imprinted maternally expressed transcript (H19) was not observed to be dysregulated in this environment. Under normoxic conditions, LEF1-AS1, MALAT1, LINC00470, H19, HOTAIR, NEAT1, and XIST were downregulated and TUSC7 was not targeted by HSV-G47∆. Overall, the present data shows HSVG47Δ treatment deregulates non-coding RNA expression in GBM-CSC tumor microenvironments.

Reprogramming of glycolysis by chemical carcinogens during tumor development

Indiscriminate usage and mismanagement of chemicals in the agricultural and industrial sectors have contaminated different environmental compartments. Exposure to these persistent and hazardous pollutants like heavy metals, endocrine disruptors, aromatic hydrocarbons, and pesticides can result in various health adversities, including cancer. Chemical carcinogens follow a similar pattern of carcinogenesis, like oxidative stress, chromosomal aberration, DNA double-strand break, mismatch repair, and misregulation of oncogenic and/or tumor suppressors. Out of several cancer-associated endpoints, cellular metabolic homeostasis is the commonest to be deregulated upon chemical exposure. Chemical carcinogens hamper glycolytic reprogramming to fuel the malignant transformation of the cells and/or promote cancer progression. Several regulators like Akt, ERK, Ras, c-Myc, HIF-1α, and p53 regulate glycolysis in chemical-induced carcinogenesis. However, the deregulation of the anabolic biochemistry of glucose during chemical-induced carcinogenesis remains to be uncovered. This review comprehensively covers the environmental chemical-induced glycolytic shift during carcinogenesis and its mechanism. The focus is also to fill the major gaps associated with understanding the fairy tale between environmental carcinogens and metabolic reprogramming. Although evidence from studies regarding glycolytic reprogramming in chemical carcinogenesis provides valuable insights into cancer therapy, exposure to a mixture of toxicants and their mechanism of inducing carcinogenesis still needs to be studied.

Effects of Whole-Body Vibration on Breast Cancer Bone Metastasis and Vascularization in Mice

We evaluated whether whole-body vibration (WBV) prevented bone loss induced by breast cancer (BC) metastasis and the involvement of bone marrow vasculature. One day after orthotopic transplantation of mammary 4T1 tumor cells, 8-week-old BALB/c mice were subjected to 0.3 g/90 Hz vertical vibration for 20 min/day for 5 days/week (BC-WBV) or sham-handled (BC-Sham) over 3 weeks. Age-matched intact mice (Intact) were also sham-handled. Both tibiae were harvested from BC-WBV (n = 7), BC-Sham (n = 9), and Intact (n = 5) mice for bone structure imaging by synchrotron radiation-based computed tomography (SRCT) and hematoxylin and eosin staining, whereas right tibiae were harvested from other BC-WBV and BC-Sham (n = 6 each) mice for vascular imaging by SRCT. Tumor cells were similarly widespread in the marrow in BC-WBV and BC-Sham mice. In BC-Sham mice, cortical bone volume, trabecular volume fraction, trabecular thickness, trabecular number density, and bone mineral density were smaller, and marrow volume and trabecular separation were larger than in Intact mice. However, although trabecular thickness was smaller in BC-WBV than Intact mice, the others did not differ between the two groups. Serum osteocalcin tended to be higher in BC-WBV than BC-Sham mice. Compared with BC-Sham mice, BC-WBV mice had a smaller vessel diameter, a trend of a larger vessel number density, and smaller vessel diameter heterogeneity. In conclusion, WBV mitigates bone loss in BC bone metastasis, which may be partly due to increased bone anabolism. The alteration of marrow vasculature appears to be favorable for anti-tumor drug delivery. Further studies are needed to clarify the multiple actions of WBV on bone, tumor, and marrow vasculature and how they contribute to bone protection in BC metastasis.

Peroxide mediated oxygen delivery in cancer therapy

Hypoxia is a serious obstacle in cancer treatment. The aberrant vascular network as well as the abnormal extracellular matrix arrangement results in formation of a hypoxic regions in tumors which show high resistance to the curing. Hypoxia makes the cancer treatment challengeable via two mechanisms; first and foremost, hypoxia changes the cell metabolism and leads the cells towards an aggressive and metastatic phenotype and second, hypoxia decreases the efficiency of the various cancer treatment modalities. Most of the cancer treatment methods including chemotherapy, radiotherapy, photodynamic therapy, sonodynamic therapy and immunotherapy are negatively affected by the oxygen deprivation. Therefore, the regional oxygenation is requisite to alleviate the negative impacts of the hypoxia on tumor cells and tumor therapy modalities. A great deal of effort has been put forth to resolve the problem of hypoxia in tumors. Peroxides have gained tremendous attention as oxygen generating components in cancer therapy. The concurrent loading of the peroxides and cancer treatment components into a single delivery system can bring about a multipurpose delivery system and substantially encourage the success of the cancer amelioration. In this review, we have tried to after the description of a relation between hypoxia and cancer treatment modalities, discuss the role of peroxides in tumor hyperoxygenation and cancer therapy success. Thereafter, we have summarized a number of vehicles for the delivery of the peroxide alone or in combination with other therapeutic components for cancer treatment.

Chromatin regulators-related lncRNA signature predicting the prognosis of kidney renal clear cell carcinoma and its relationship with immune microenvironment: A study based on bioinformatics and experimental validation

Background: Kidney Renal Clear cell carcinoma (KIRC) is a major concern in the urinary system. A lot of researches were focused on Chromatin Regulators (CRs) in tumors. In this study, CRs-related lncRNAs (CRlncRNAs) were investigated for their potential impact on the prognosis of KIRC and the immune microenvironment.

Methods: The TCGA database was used to obtain transcriptome and related clinical information. CRs were obtained from previous studies, whereas CRlncRNAs were obtained by differential and correlation analysis. We screened the lncRNAs for the signature construction using regression analysis and LASSO regression analysis. The effectiveness of the signature was evaluated using the Kaplan-Meier (K-M) curve and Receiver Operating Characteristic curve (ROC). Additionally, we examined the associations between the signature and Tumor Microenvironment (TME), and the efficacy of drug therapy. Finally, we further verified whether these lncRNAs could affect the biological function of KIRC cells by functional experiments such as CCK8 and transwell assay.

Results: A signature consisting of 8 CRlncRNAs was constructed to predict the prognosis of KIRC. Quantitative Real-Time PCR verified the expression of 8 lncRNAs at the cell line and tissue level. The signature was found to be an independent prognostic indicator for KIRC in regression analysis. This signature was found to predict Overall Survival (OS) better for patients in the subgroups of age, gender, grade, stage, M, N0, and T. Furthermore, a significant correlation was found between riskScore and immune cell infiltration and immune checkpoint. Finally, we discovered several drugs with different IC50 values in different risk groups using drug sensitivity analysis. And functional experiments showed that Z97200.1 could affect the proliferation, migration and invasion of KIRC cells.

Conclusion: Overall, the signature comprised of these 8 lncRNAs were reliable prognostic biomarkers for KIRC. Moreover, the signature had significant potential for assessing the immunological landscape of tumors and providing individualized treatment.

Differential Expression of HIF1A, EPAS1, and VEGF Genes in Benign and Malignant Ovarian Neoplasia

Simple Summary

Ovarian cancer (OC) has the highest mortality rate of all gynecological malignancies. Moreover, at the time of the first clinical manifestation, most patients have an advanced stage of the disease. Our study examined differences in mRNA levels of hypoxia-inducible factor 1-alpha (HIF1A); endothelial PAS domain protein 1, also known as hypoxia-inducible factor 2-alpha (HIF2A/EPAS1); and vascular endothelial growth factor A (VEGFA) between cancerous tissue, benign hyperplastic changes in the ovary, and normal tissue. We found that gene expression changes were visible not only in the case-control study, but also along with changes in severity. We observed disturbances in the expression levels of interdependent genes. Our findings suggest that mutual association in the expression of both HIF1A and HIF2A/EPAS1 with VEGFA has prognostic importance for patients with OC. Our observations may help identify patients for clinical trials aimed at inhibiting the hypoxia-induced neovascularization-dependent pathways.

Abstract

Ovarian cancer (OC) has the highest mortality rate of all gynecological malignancies. Moreover, at the time of the first clinical manifestation, most patients have an advanced stage of the disease. Our study examined differences in mRNA levels of hypoxia-inducible factor 1-alpha (HIF1A); endothelial PAS domain protein 1, also known as hypoxia-inducible factor 2-alpha (HIF2A/EPAS1); and vascular endothelial growth factor A (VEGFA) between cancerous tissue, benign hyperplastic changes in the ovary, and normal tissue. Our cohorts consisted of 52 patients diagnosed with OC (n = 55), benign non-cancerous changes (n = 21), and normal tissue samples (n = 38). The mRNA expression level was evaluated using RT-qPCR. We found that gene expression changes were visible not only in the case-control study, but also along with changes in severity. Additionally, the gene expression was differentiated in age, BMI, menopausal status, and the number of comorbidy-related groups. Furthermore, our findings demonstrate that analyzing the correlation between genes is essential. In a case-to-case and case-to-control study, we observed disturbances in the expression levels of interdependent genes. Our findings suggest that mutual association in the expression of both HIF1A and HIF2A/EPAS1 with VEGFA has prognostic importance for patients with OC. Our observations may help identify patients for clinical trials aimed at inhibiting the hypoxia-induced neovascularization-dependent pathways.

Unraveling tumor microenvironment of small-cell lung cancer: implications for immunotherapy

Small-cell lung cancer (SCLC) is an aggressive lung cancer subtype and its first-line treatment has remained unchanged for decades. In recent years, immunotherapy has emerged as a therapeutic strategy for tumor treatment, whereas, patients with SCLC exhibit poor overall responses to immunotherapy alone, which highlights the necessity for combinatorial approaches. The tumor microenvironment (TME), an integral component in cancer, is widely implicated in tumorigenesis and tumor metastasis. The interactions of various cells within TME shape the adverse conditions of the tumor microenvironment (characterized by hypoxia, nutrient restriction, and acidity) and are considered responsible for the modest therapeutic responses to immunotherapy. Several studies have suggested that adverse TME can regulate immune cell activation and function. However, the specific regulatory mechanisms and their implications on immunotherapy remain unclear. Thus, it is worth unraveling the characteristics of TME and its impact on antitumor immunity, in the hope of devising novel strategies to reinforce immunotherapeutic effects on SCLC. In this review, we firstly elaborate on the immune landscape of SCLC and the formation of three remarkable characteristics in TME, as well as the interaction among them. Next, we summarize the latest findings regarding the impacts of adverse TME on immune cells and its targeted therapy in SCLC. Finally, we discuss the ongoing trials in combination therapy and potential directions of SCLC therapy. Collectively, the findings combined here are expected to aid the design of trials for combining immunotherapy with therapy targeting the TME of SCLC.

Nilotinib alleviated acetaminophen-induced acute hepatic injury in mice through inhibiting HIF-1alpha/VEGF-signaling pathway

The current study inspects the impact of nilotinib (Nil) on liver damage caused by acetaminophen (APAP). Adult male mice were pre-treated with nilotinib (Nil,5 and 10 mg/kg) orally once daily for 7 days followed by a single intraperitoneal administration of acetaminophen (APAP, 200 mg/kg) on the 7th day. The results indicated that nilotinib significantly decreased APAP-induced elevation of biochemical markers (ALT, AST, ALP, LDH, ɤ GT, and total bilirubin). Additionally, nilotinib significantly increased hepatic GSH and SOD content, while decreased MDA content. Nil significantly suppressed the expression of HIF-1α and VEGF. Histopathological examination of hepatic tissue from Nil-treated mice revealed that Nil reduced acetaminophen-induced necrosis.

Regulatory mechanisms and function of hypoxia-induced long noncoding RNA NDRG1-OT1 in breast cancer cells

Hypoxia is a classic feature of the tumor microenvironment that has profound effects on cancer progression and is tightly associated with poor prognosis. Long noncoding RNAs (lncRNAs), a component of the noncoding genome, have been increasingly investigated due to their diverse roles in tumorigenesis. Previously, a hypoxia-induced lncRNA, NDRG1-OT1, was identified in MCF-7 breast cancer cells using next-generation sequencing. However, the regulatory mechanisms of NDRG1-OT1 remain elusive. Therefore, the purpose of this study was to investigate the regulatory mechanisms and functional roles of NDRG1-OT1 in breast cancer cells. Expression profiling of NDRG1-OT1 revealed that it was upregulated under hypoxia in different breast cancer cells. Overexpression and knockdown of HIF-1α up- and downregulated NDRG1-OT1, respectively. Luciferase reporter assays and chromatin immunoprecipitation assays validated that HIF-1α transcriptionally activated NDRG1-OT1 by binding to its promoter (-1773 to -1769 and -647 to -643 bp). Next, to investigate whether NDRG1-OT1 could function as a miRNA sponge, results of in silico analysis, expression profiling of predicted miRNAs, and RNA immunoprecipitation assays indicated that NDRG1-OT1 could act as a miRNA sponge of miR-875-3p. In vitro and in vivo functional assays showed that NDRG1-OT1 could promote tumor growth and migration. Lastly, a small peptide (66 a.a.) translated from NDRG1-OT1 was identified. In summary, our findings revealed novel regulatory mechanisms of NDRG1-OT1 by HIF-1α and upon miR-875-3p. Also, NDRG1-OT1 promoted the malignancy of breast cancer cells and encoded a small peptide.

Enhancing the therapeutic efficacy of nanoparticles for cancer treatment using versatile targeted strategies

Poor targeting of therapeutics leading to severe adverse effects on normal tissues is considered one of the obstacles in cancer therapy. To help overcome this, nanoscale drug delivery systems have provided an alternative avenue for improving the therapeutic potential of various agents and bioactive molecules through the enhanced permeability and retention (EPR) effect. Nanosystems with cancer-targeted ligands can achieve effective delivery to the tumor cells utilizing cell surface-specific receptors, the tumor vasculature and antigens with high accuracy and affinity. Additionally, stimuli-responsive nanoplatforms have also been considered as a promising and effective targeting strategy against tumors, as these nanoplatforms maintain their stealth feature under normal conditions, but upon homing in on cancerous lesions or their microenvironment, are responsive and release their cargoes. In this review, we comprehensively summarize the field of active targeting drug delivery systems and a number of stimuli-responsive release studies in the context of emerging nanoplatform development, and also discuss how this knowledge can contribute to further improvements in clinical practice.

Microneedle Patches with O2 Propellant for Deeply and Fast Delivering Photosensitizers: Towards Improved Photodynamic Therapy

Photodynamic therapy (PDT) is an emerging technique for treating tumors. Especially, topical administration of photosensitizers (PSs) is more favorable for superficial tumor treatments with low systematic phototoxicity. Yet, ineffective migration of PSs to targeted tumor tissues and rapid consumption of O₂ during PDT greatly limit their effects. Herein, PS-loaded microneedle (MN) patches with O₂ propellant for a deeper and faster transdermal delivery of PS and improved PDT by embedding sodium percarbonate (SPC) into dissolving poly(vinyl pyrrolidone) MNs are presented. It is shown that SPC in the MNs can react with surrounding fluid to generate gaseous oxygen bubbles, forming vigorous fluid flows and thus greatly enhancing PS of chlorin e6 (Ce6) penetration in both hydrogel models and skin tissues. Reactive oxygen species (ROS) in hypoxic breast cancer cells (4T1 cells) are greatly increased by rapid penetration of PS and relief of hypoxia in vitro, and Ce6-loaded SPC MNs show an excellent cell-killing effect. Moreover, lower tumor growth rate and tumor mass after a 20-d treatment in tumor-bearing mice model verify the improved PDT in gaseous oxygen-droved delivery of PS. This study demonstrates a facile yet effective route of MN delivery of PSs for improved PDT in hypoxic tumor treatment.

Hemin-loaded black phosphorus-based nanosystem for enhanced photodynamic therapy and a synergistic photothermally/photodynamically activated inflammatory immune response

The biocompatible nanosystem integrating hemin into black phosphorus nanosheets was ingeniously constructed through the easy modified strategy. Taking advantage of the enhanced permeability and retention (EPR) effect, the designed nanosystem could accumulate into the tumor location, leading to attractive cytotoxicity through the enhanced photodynamic therapy (PDT) ascribing to the catalytic oxygen supply and GSH depletion of hemin. Simultaneously, combining PDT and photothermal therapy (PTT) showed an apparent promotion in anti-tumor effect. Moreover, inflammatory response and immune activation amplified anti-tumor effect, which could compensate limitations of exogenous therapy (i.e., limited tissue depth and intensity-dependent curation effect) and potentiate the efficiency of the endogenous immune-activating behavior. Especially, the designed nanosystem degraded followed by being metabolized in the blood circulation. By and large, this constructed nanosystem provides the new insight into designing biocompatible nanomaterials and paves the ideal way for anti-tumor therapy. STATEMENT OF SIGNIFICANCE: Biocompatible nanomaterials-based synergistic tumor therapy offers the potential application prospect. Taking advantage of degradable black phosphorus, the nanosystem integrating hemin into black phosphorus for the enhanced photodynamic therapy and synergistic photothermal-photodynamic activating inflammation-immune response was developed and the results demonstrate that tumor growth was inhibited followed by activating inflammatory factors and leading to satisfactory immune response.

Recent advances in bacterial therapeutics based on sense and response

Intelligent drug delivery is a promising strategy for cancer therapies. In recent years, with the rapid development of synthetic biology, some properties of bacteria, such as gene operability, excellent tumor colonization ability, and host-independent structure, make them ideal intelligent drug carriers and have attracted extensive attention. By implanting condition-responsive elements or gene circuits into bacteria, they can synthesize or release drugs by sensing stimuli. Therefore, compared with traditional drug delivery, the usage of bacteria for drug loading has better targeting ability and controllability, and can cope with the complex delivery environment of the body to achieve the intelligent delivery of drugs. This review mainly introduces the development of bacterial-based drug delivery carriers, including mechanisms of bacterial targeting to tumor colonization, gene deletions or mutations, environment-responsive elements, and gene circuits. Meanwhile, we summarize the challenges and prospects faced by bacteria in clinical research, and hope to provide ideas for clinical translation.

Non-canonical function of an Hif-1α splice variant contributes to the sustained flight of locusts

The hypoxia inducible factor (Hif) pathway is functionally conserved across metazoans in modulating cellular adaptations to hypoxia. However, the functions of this pathway under aerobic physiological conditions are rarely investigated. Here, we show that Hif-1α2, a locust Hif-1α isoform, does not induce canonical hypoxic responses but functions as a specific regulator of locust flight, which is a completely aerobic physiological process. Two Hif-1α splice variants were identified in locusts, a ubiquitously expressed Hif-1α1 and a muscle-predominantly expressed Hif-1α2. Hif-1α1 that induces typical hypoxic responses upon hypoxia exposure remains inactive during flight. By contrast, the expression of Hif-1α2, which lacks C-terminal transactivation domain, is less sensitive to oxygen tension but induced extensively by flying. Hif-1α2 regulates physiological processes involved in glucose metabolism and antioxidation during flight and sustains flight endurance by maintaining redox homeostasis through upregulating the production of a reactive oxygen species (ROS) quencher, DJ-1. Overall, this study reveals a novel Hif-mediated mechanism underlying prolonged aerobic physiological activity.

Rapid generation of a mouse model for evaluating on-target normal tissue toxicity of human CAR-T cells using replication-defective recombinant adenovirus

INTRODUCTION

The on-target off-tumor toxicity of chimeric antigen receptor-engineered T cells (CAR-T) might lead to fatal side effects in cancer patients, which remains as a major obstacle to the clinical application of CAR-T immunotherapy. The off-tumor on-target normal tissue toxicity of CAR-T cells needs to be evaluated in preclinical studies using rational animal models.

OBJECTIVES

We aim to develop a rational animal model for assessing the off-tumor on-target normal tissue toxicity of various CAR-T cell designs quickly.

METHODS

We used a recombinant adenovirus type 5 carrying human HER2/ERBB2 (Ad5-HER2) or CD47 gene (Ad5-CD47) to rapidly generate a mouse model with tunable human antigen expression on normal liver tissue to determine immunotoxicity of traditional CAR-T and hypoxia-response CAR-T cells in vivo.

RESULTS

The obvious liver damage and lymphocyte infiltration were not observed in mice with human antigen-high livers 8 days post-infection. Interestingly, the lethal liver damage, systemic cytokine release and CAR-T cells infiltration in liver were only observed in mice that received traditional CAR-T cells, but not in hypoxia-response CAR-T cells.

CONCLUSION

Adenovirus-based expression of target antigen in normal mouse tissue may be a useful method for assessing on-target CAR-T cell toxicity in normal tissues, especially various CAR-T cell designs that have the potency of conditional regulation in tumor microenvironment (TME).

A Novel hepatocellular carcinoma specific hypoxic related signature for predicting prognosis and therapeutic responses

Hypoxia is an important feature of the tumor microenvironment(TME) and is closely associated with cancer metastasis, immune evasion, and drug resistance. However, the precise role of hypoxia in hepatocellular carcinoma(HCC), as well as its influence on the TME, and drug sensitivity remains unclear. We found the excellent survival prediction value of Hypoxia_DEGs_Score model. In hypoxic HCC, somatic mutation, copy number variation, and DNA methylation were closely related to hypoxic changes and affected tumorigenesis, progression, metastasis, and drug resistance. In HCC, aggravated hypoxic stress was found to be accompanied by an immune exclusion phenotype and increased infiltration of immunosuppressive cells. In the validation cohort, patients with high Hypoxia_DEGs_Score were found to have worse immunotherapeutic outcomes and prognoses, and may benefit from drugs against cell cycle signaling pathways rather than those inhibiting the PI3K/mTOR pathway. Hypoxia_DEGs_Score has an excellent predictive capability of changes in the TME, the efficacy of immunotherapy, and the response of drugs. Therefore, Hypoxia_DEGs_Score can help develop personalized immunotherapy regimens and improve the prognosis of HCC patients.

LRP-1 receptor combines EGFR signalling and eHsp90α autocrine to support constitutive breast cancer cell motility in absence of blood supply

Tumor cells face constant stress of ischemic (nutrient paucity and hypoxia) environment when they migrate and invade too fast to outgrow the nearest blood vessels. During the temporary loss of support from circulation, the tumor cells must act self-sufficient to survive and then to migrate to re-connect with the nearest blood supply or die. We have previously reported that ablation of the low-density lipoprotein receptor-related protein 1 (LRP-1) completely nullified the ability of tumour cells to migrate and invade under serum-free conditions in vitro and to form tumours in vivo. The mechanism behind the important function by cell surface LRP-1 was not fully understood. Herein we show that LRP-1 orchestrates two parallel cell surface signalling pathways to support the full constitutive tumour cell migration. First, LRP-1 stabilizes activated epidermal growth factor receptor (EGFR) to contribute half of the pro-motility signalling. Second, LRP-1 mediates secreted Hsp90α autocrine signalling to bring the other half of pro-motility signalling. Only combined inhibitions of the EGFR signalling and the eHsp90α autocrine signalling led to the full blockade of the tumour cell migration as the LRP-1 depletion did. This finding uncovers a novel mechanism by which certain breast cancer cells use LRP-1 to engage parallel signalling pathways to move when they lose contact with blood support.

Hypoxia, a key factor in the immune microenvironment

The physical and chemical pressures in the tumor microenvironment (TME) play an important role in tumor development by regulating stromal elements, including immune cells. Hypoxia can induce a cascade of events in tumor initiation and development via immune regulation. As a dangerous factor, hypoxia activates multiple signaling pathways to reshape the immune microenvironment, leading to immunosuppression. Consequently, targeting hypoxia in the TME is a potential strategy to prevent immune escape and inhibit malignant tumor progression. In this review, we summarized the role of hypoxia-induced factors in the tumor immune escape process and provide a novel pathway to restrain tumor progression and development.

An NIR-II Photothermally Triggered "Oxygen Bomb" for Hypoxic Tumor Programmed Cascade Therapy

Hypoxia, as a characteristic feature of solid tumors, has a close relationship with tumor resistance to photodynamic therapy (PDT) and chemotherapy. Perfluorocarbon (PFC) is reported to relieve hypoxic in solid tumors by acting as an oxygen carrier via several nanostructures. However, the oxygen delivery process is mostly driven by a concentration gradient, which is uncontrollable. Herein, a photothermally controlled "oxygen bomb" PSPP-Au₉₈₀ -D is designed by encapsulating a PFC core within a functionalized bilayer polymer shell. Near-infrared second window photothermal agent gold nanorods with excellent photo-to-heat energy-conversion ability are fabricated on the surface of the polymer shell via an innovative modified two-step seedless ex situ growth process to thermally trigger O₂  release. Then, a programmed cascade therapy strategy is customized for hypoxic orthotopic pancreatic cancer. First, PSPP-Au₉₈₀ -D is irradiated by a 980 nm laser to photothermally trigger O₂  infusing into the hypoxic tumor microenvironment, which is accompanied by local hyperemia and doxorubicin release. Subsequently, a 680 nm laser is used to generate singlet oxygen in the oxygenated tumor microenvironment for PDT. This choreographed programmed cascade therapy strategy will provide a new route for suppressing hypoxic tumor growth under mild conditions based on controllable and effective oxygen release.

Extracellular Heat Shock Protein-90 (eHsp90): Everything You Need to Know

“Extracellular” Heat Shock Protein-90 (Hsp90) was initially reported in the 1970s but was not formally recognized until 2008 at the 4th International Conference on The Hsp90 Chaperone Machine (Monastery Seeon, Germany). Studies presented under the topic of “extracellular Hsp90 (eHsp90)” at the conference provided direct evidence for eHsp90’s involvement in cancer invasion and skin wound healing. Over the past 15 years, studies have focused on the secretion, action, biological function, therapeutic targeting, preclinical evaluations, and clinical utility of eHsp90 using wound healing, tissue fibrosis, and tumour models both in vitro and in vivo. eHsp90 has emerged as a critical stress-responding molecule targeting each of the pathophysiological conditions. Despite the studies, our current understanding of several fundamental questions remains little beyond speculation. Does eHsp90 indeed originate from purposeful live cell secretion or rather from accidental dead cell leakage? Why did evolution create an intracellular chaperone that also functions as a secreted factor with reported extracellular duties that might be (easily) fulfilled by conventional secreted molecules? Is eHsp90 a safer and more optimal drug target than intracellular Hsp90 chaperone? In this review, we summarize how much we have learned about eHsp90, provide our conceptual views of the findings, and make recommendations on the future studies of eHsp90 for clinical relevance.

Free-Radical Cascade Generated by AIPH/Fe3O4-Coloaded Nanoparticles Enhances MRI-Guided Chemo/Thermodynamic Hypoxic Tumor Therapy

Free radicals, including reactive oxygen species (ROS), play a critical role in determining cell's fate. When the level of free radicals is increased to a fatal value, it causes cancer cells to undergo senescence or cell death. Strategies that target this mechanism offer promising therapies against cancer. However, efficient and sustainable systems that generate free radicals, especially oxygen-independent systems, remain deficient. Herein, functionalized PLGA-based nanocomposites that efficiently co-deliver magnetic nanoparticles and 2,2'-azobis[2-(2-imidazolin-2-yl) propane]-dihydrochloride (AIPH) were fabricated to achieve photothermal-induced thermodynamic therapy combined with macrophage polarization strategies; this therapy targets hypoxic tumors through the generation of an oxygen-independent free-radical cascade. These hybrid NPs can accumulate in the tumor microenvironment, and the encapsulated MNPs not only serve as contrast agents for enhanced magnetic resonance imaging but also exhibit the expected photothermal conversion and trigger the decomposition of AIPH to generate free radicals, thus causing cancer cell death. More importantly, the cell debris from apoptotic or necrotic cancer cells carries nondegraded MNPs, which can be endocytosed by recruited TAMs. MNPs can further induce TAMs to polarize to the M1 subtype to subsequently generate ROS. This study provides an alternative method for the generation of an oxygen-independent free-radical cascade for tumor co-therapy guided by magnetic resonance imaging PTT/TDT.

Novel Drugs with High Efficacy against Tumor Angiogenesis

Angiogenesis is involved in physiological and pathological processes in the body. Tumor angiogenesis is a key factor associated with tumor growth, progression, and metastasis. Therefore, there is great interest in developing antiangiogenic strategies. Hypoxia is the basic initiating factor of tumor angiogenesis, which leads to the increase of vascular endothelial growth factor (VEGF), angiopoietin (Ang), hypoxia-inducible factor (HIF-1), etc. in hypoxic cells. The pathways of VEGF and Ang are considered to be critical steps in tumor angiogenesis. A number of antiangiogenic drugs targeting VEGF/VEGFR (VEGF receptor) or ANG/Tie2, or both, are currently being used for cancer treatment, or are still in various stages of clinical development or preclinical evaluation. This article aims to review the mechanisms of angiogenesis and tumor angiogenesis and to focus on new drugs and strategies for the treatment of antiangiogenesis. However, antitumor angiogenic drugs alone may not be sufficient to eradicate tumors. The molecular chaperone heat shock protein 90 (HSP90) is considered a promising molecular target. The VEGFR system and its downstream signaling molecules depend on the function of HSP90. This article also briefly introduces the role of HSP90 in angiogenesis and some HSP90 inhibitors.

The RAGE/multiligand axis: a new actor in tumor biology

The receptor for advanced glycation end-products (RAGE) is a multiligand binding and single-pass transmembrane protein which actively participates in several chronic inflammation-related diseases. RAGE, in addition to AGEs, has a wide repertoire of ligands, including several damage-associated molecular pattern molecules or alarmins such as HMGB1 and members of the S100 family proteins.

Over the last years, a large and compelling body of evidence has revealed the active participation of the RAGE axis in tumor biology based on its active involvement in several crucial mechanisms involved in tumor growth, immune evasion, dissemination, as well as by sculpturing of the tumor microenvironment as a tumor-supportive niche. In the present review, we will detail the consequences of the RAGE axis activation to fuel essential mechanisms to guarantee tumor growth and spreading.

Dual Molecular Design toward a Lysosome-Tagged AIEgen and Heavy-Atom-Free Photosensitizers for Hypoxic Cancer Photodynamic Therapy

To date, a large number of photosensitizers (PS) have introduced heavy atoms to improve the ISC process and 1O2 generation. However, they often show low efficiency in hypoxic conditions, aggregate states, and turn-off PDT in the dark. Besides that, the toxicity of heavy metals is also concerned. Therefore, we developed lysosome-targeted heavy-metal-free PS (3S and 4S) based on thionated naphthalimide for hypoxic cancer photodynamic therapy (PDT), not only under white light but also in the dark via thermal-induced 1O2 generation. AIEgen (3O and 4O) were prepared for studying the PDT action of PSs (3S and 4S) in lysosome and aggregate state. We also examined the photophysical properties of AIEgen (3O and 4O) and PS (3S and 4S) by UV–vis absorption, fluorescent emission spectra, and theoretical calculations.

Novel Hypoxia-Associated Gene Signature Depicts Tumor Immune Microenvironment and Predicts Prognosis of Colon Cancer Patients

Hypoxia, a typical hallmark of numerous tumors, indicates poor infiltration of antitumor lymphocytes, as well as facilitates the development, progression, and drug resistance of malignant cells. Here, the present research was performed to identify novel hypoxia-related molecular markers and their correlation to the tumor immune microenvironment (TIME) in colon cancer. The expression of hypoxia-related gene signature was extracted from The Cancer Genome Atlas (TCGA) COAD cohort. Based on this signature, a risk score model was constructed using the Lasso regression model. Its discrimination ability and stability were validated in another independent cohort (GSE17536) from Gene Expression Omnibus (GEO) database. Moreover, molecular biology experiments (quantitative real-time PCR and multiple immunohistochemistry) were performed to validate the results of bioinformatics analyses. Three hub genes, including PPFIA4, SERPINE1, and STC2, were chosen to build the risk score model. All of these genes were increasingly expressed in the hypoxia subgroup (HS). Compared with the normoxia subgroup (NS), HS had worse pathological features (T, N, M, and stage) and overall survival (OS), more expression of immune checkpoint molecules, poorer infiltration of some pro-inflammation immune cells (CD4⁺ T cells and CD8⁺ T cells), and enriched infiltration of M0/M2 macrophages. After the risk model was proven to be valuable and stable, a nomogram was built based on this model and some clinicopathological factors. Moreover, it had been identified that three hub genes were all increasingly expressed in hypoxic conditions by quantitative real-time PCR (qPCR). The results of multiple immunohistochemistry (mIHC) also showed that higher expression of hub genes was associated with poorer infiltration of pro-inflammation immune cells (CD8⁺ T cells and M1 macrophages) and richer infiltration of anti-inflammation immune cells (Treg cells and M2 macrophages). In conclusion, the present study uncovered the relations among hypoxia, TIME, and clinicopathological features of colon cancer. It might provide new insight and a potential therapeutic target for immunotherapy.

Effect of Hypoxia-Induced Micro-RNAs Expression on Oncogenesis

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression at the post-transcriptional level. An aberrant regulation of gene expression by miRNAs is associated with numerous diseases, including cancer. MiRNAs expression can be influenced by various stimuli, among which hypoxia; however, the effects of different types of continuous hypoxia (moderate or marked) on miRNAs are still poorly studied. Lately, some hypoxia-inducible miRNAs (HRMs, hypoxia-regulated miRNAs) have been identified. These HRMs are often activated in different types of cancers, suggesting their role in tumorigenesis. The aim of this study was to evaluate changes in miRNAs expression both in moderate continuous hypoxia and marked continuous hypoxia to better understand the possible relationship between hypoxia, miRNAs, and colorectal cancer. We used RT-PCR to detect the miRNAs expression in colorectal cancer cell lines in conditions of moderate and marked continuous hypoxia. The expression of miRNAs was analyzed using a two-way ANOVA test to compare the differential expression of miRNAs among groups. The levels of almost all analyzed miRNAs (miR-21, miR-23b, miR-26a, miR-27b, and miR-145) were greater in moderate hypoxia versus marked hypoxia, except for miR-23b and miR-21. This study identified a series of miRNAs involved in the response to different types of continuous hypoxia (moderate and marked), highlighting that they play a role in the development of cancer. To date, there are no other studies that demonstrate how these two types of continuous hypoxia could be able to activate different molecular pathways that lead to a different expression of specific miRNAs involved in tumorigenesis.

Development of a pO2-Guided Fine Needle Tumor Biopsy Device

Tumor biopsies are an important aspect of oncology providing a guide for medical treatment and evaluation of disease progression. Highly heterogenous tumors have complex regions of active cancer cells interdigitated with necrotic tissue and healthy noncancerous tissue. The reliable access to tumor tissue pathology is therefore challenging and usually requires multiple needle insertions with accompanying patient discomfort and risk of infection. Oxygen levels provide a means of detecting and evaluating tumor tissue with levels reduced by 2-fold to 22-fold, depending on the type of organ. However, if the biopsy needle is placed in an area of normal tissue, there is always a chance that no diagnostic cells will be acquired for meaningful pathology and molecular analysis. While not the case in all tumors, there are cases where the in vivo oxygen levels differ with tumor cells having a value of pO2 lying between the anoxic necrotic tissue and normoxic normal tissue. The level of oxygen in tumor cells can also vary with time as related to complex biochemical pathways. The efficacy of radiation therapy is also sensitive to oxygen levels in tumors. Lower levels of oxygen present greater resistance to treatment. To address these concerns, a pO2-guided biopsy needle (OGBN) was developed to determine oxygen levels and fluctuations in highly resolved regions of tumors, in order to aide in determining the optimal region for cell sampling help in determining medical treatment options.

Claudin-1/4 as directly target gene of HIF-1α can feedback regulating HIF-1α by PI3K-AKT-mTOR and impact the proliferation of esophageal squamous cell though Rho GTPase and p-JNK pathway

Immunohistochemical microarray comprising 80 patients with esophageal squamous cell carcinoma (ESCC) and discovered that the expression of CLDN1 and CLDN4 were significantly higher in cancer tissues compared to para-cancerous tissues. Furthermore, CLDN4 significantly affected the overall survival of cancer patients. When two ESCC cell lines (TE1, KYSE410) were exposed to hypoxia (0.1% O₂), CLDN1/4 was shown to influence the occurrence and development of esophageal cancer. Compared with the control culture group, the cancer cells cultured under hypoxic conditions exhibited obvious changes in CLDN1 and CLDN4 expression at both the mRNA and protein levels. Through genetic intervention and Chip, we found that HIF-1α could directly regulate the expression of CLDN1 and CLDN4 in cancer cells. Hypoxia can affect the proliferation and apoptosis of cancer cells by regulating the PI3K-Akt-mTOR pathway. Molecular analysis further revealed that CLDN1 and CLDN4 can participate in the regulation process and had a feedback regulatory effect on HIF-1α expression in cancer cells. In vitro cellular experiments and vivo experiments in nude mice further revealed that changes in CLDN4 expression in cancer cells could affect the proliferation of cancer cells via regulation of Rho GTP and p-JNK pathway. Whether CLDN4 can be target for the treatment of ESCC needs further research.