Tumour hypoxia, chemotherapeutic resistance and hypoxia-related therapies

Hyperbaric Oxygen Therapy for Managing Cancer Treatment Complications: A Safety Evaluation

Background and Objectives: Hyperbaric oxygen therapy (HBOT) has shown promise in managing complications due to cancer treatments, particularly those related to radiotherapy and surgery. Despite its clinical benefits, concerns persist regarding its potential to influence cancer progression. This study aimed to evaluate the safety and clinical outcomes of HBOT in patients with active or previously treated solid tumors. Methods: A retrospective analysis was conducted on patients with solid tumors who underwent at least five HBOT sessions. Comprehensive data, including patient demographics, cancer type, total number of HBOT sessions, imaging findings, and clinical outcomes (recurrence, metastasis, and mortality), were collected. Descriptive statistics and the relationship between the number of HBOT sessions and long-term cancer outcomes were analyzed. Results: This study included 45 patients (median age: 64 years; 60% male) who received a median of 27 HBOT sessions. At initiation, 27.9% of the patients were classified as cured, 53.5% were in remission, and 18.6% had active cancer. Over a median follow-up period of 783 days, 8.7% experienced recurrence, 2.7% had persistent active cancer, and 59.5% had no recurrence. No HBOT-related complications were observed during the course of HBOT. Statistical analyses revealed no significant correlations between the number of HBOT sessions and metastasis (p = 0.213) or mortality (p = 0.881). Conclusions: HBOT appears to be a safe and effective adjunctive therapy for managing complications in patients with solid tumors. No evidence was found to suggest HBOT contributes to tumor progression, recurrence, or metastasis. Future prospective studies with larger cohorts are needed to confirm these results and further evaluate the therapeutic role of HBOT in oncology.

Hypoxia as a critical player in extracellular vesicles-mediated intercellular communication between tumor cells and their surrounding microenvironment

In the past years, increasing attention has been paid to the role of extracellular vesicles (EVs) as mediators of intercellular communication in cancer. These small size particles mediate the intercellular transfer of important bioactive molecules involved in malignant initiation and progression. Hypoxia, or low partial pressure of oxygen, is recognized as a remarkable feature of solid tumors and has been demonstrated to exert a profound impact on tumor prognosis and therapeutic efficacy. Indeed, the high-pitched growth rate and chaotic neovascular architecture that embodies solid tumors results in a profound reduction in oxygen pressure within the tumor microenvironment (TME). In response to oxygen-deprived conditions, tumor cells and their surrounding milieu develop homeostatic adaptation mechanisms that contribute to the establishment of a pro-tumoral phenotype. Latest evidence suggests that the hypoxic microenvironment that surrounds the tumor bulk may be a clincher for the observed elevated levels of circulating EVs in cancer patients. Thus, it is proposed that EVs may play a role in mediating intercellular communication in response to hypoxic conditions. This review focuses on the EVs-mediated crosstalk that is established between tumor cells and their surrounding immune, endothelial, and stromal cell populations, within the hypoxic TME.

Omega-3 fatty acids: molecular weapons against chemoresistance in breast cancer

Breast cancer is the most commonly diagnosed type of cancer and the leading cause of cancer-related death in women worldwide. Highly targeted therapies have been developed for different subtypes of breast cancer, including hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, triple-negative breast cancer (TNBC) and metastatic breast cancer disease are primarily treated with chemotherapy, which improves disease-free and overall survival, but does not offer a curative solution for these aggressive forms of breast cancer. Moreover, the development of chemoresistance is a major cause of therapeutic failure in this neoplasia, leading to disease relapse and patient death. In addition, chemotherapy's adverse side effects may substantially worsen health-related quality of life. Therefore, to improve the outcome of patients with breast cancer who are undergoing chemotherapy, several therapeutic options are under investigation, including the combination of chemotherapeutic drugs with natural compounds. Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs), including docosahexaenoic and eicosapentaenoic acids, have drawn attention for their antitumoral properties and their preventive activities against chemotherapy-induced toxicities in breast cancer. A literature review was conducted on PubMed using keywords related to breast cancer, omega-3, chemoresistance, and chemotherapy. This review aims to provide an overview of the molecular mechanisms driving breast cancer chemoresistance, focusing on the role of ω-3 PUFAs in these recognized cellular paths and presenting current findings on the effects of ω-3 PUFAs combined with chemotherapeutic drugs in breast cancer management.

Key Structural Features of Microvascular Networks Leading to the Formation of Multiple Equilibria

We analyse mathematical models of blood flow in two simple vascular networks in order to identify structural features that lead to the formation of multiple equilibria. Our models are based on existing rules for blood rheology and haematocrit splitting. By performing bifurcation analysis on these simple network flow models, we identify a link between the changing flow direction in key vessels and the existence of multiple equilibria. We refer to these key vessels as redundant vessels, and relate the maximum number of equilibria with the number of redundant vessels. We vary geometric parameters of the two networks, such as vessel length ratios and vessel diameters, to demonstrate that equilibria are uniquely defined by the flow in the redundant vessels. Equilibria typically emerge in sets of three, each having a different flow characteristic in one of the network's redundant vessels. For one of the three equilibria, the flow within the relevant redundant vessel will be smaller in magnitude than the other two and the redundant vessel will contain few Red Blood Cells (RBCs), if any. For the other two equilibria, the redundant vessel contains RBCs and significant flow in the two available directions. These structural features of networks provide a useful geometric property when studying the equilibria of blood flow in microvascular networks.

Development of Hemispherical 3D Models of Human Brain and B Cell Lymphomas Using On-Chip Cell Dome System

Lymphocytes are generally non-adherent. This makes it challenging to fabricate three-dimensional (3D) structures mimicking the three-dimensional lymphoma microenvironment in vivo. This study presents the fabrication of a hemispherical 3D lymphoma model using the on-chip Cell Dome system with a hemispherical cavity (1 mm in diameter and almost 300 µm in height). Both the human brain lymphoma cell line (TK) and human B cell lymphoma cell line (KML-1) proliferated and filled the cavities. Hypoxic regions were observed in the center of the hemispherical structures. CD19 expression did not change in either cell line, while CD20 expression was slightly upregulated in TK cells and downregulated in KML-1 cells cultured in the Cell Dome compared to those cultured in two-dimensional (2D) flasks. In addition, both TK and KML-1 cells in the hemispherical structures exhibited higher resistance to doxorubicin than those in 2D flasks. These results demonstrate the effectiveness of the on-chip Cell Dome for fabricating 3D lymphoma models and provide valuable insights into the study of lymphoma behavior and the development of new drugs for lymphoma treatment.

Cell microencapsulation techniques for cancer modelling and drug discovery

Cell encapsulation into spherical microparticles is a promising bioengineering tool in many fields, including 3D cancer modelling and pre-clinical drug discovery. Cancer microencapsulation models can more accurately reflect the complex solid tumour microenvironment than 2D cell culture and therefore would improve drug discovery efforts. However, these microcapsules, typically in the range of 1 - 5000 µm in diameter, must be carefully designed and amenable to high-throughput production. This review therefore aims to outline important considerations in the design of cancer cell microencapsulation models for drug discovery applications and examine current techniques to produce these. Extrusion (dripping) droplet generation and emulsion-based techniques are highlighted and their suitability to high-throughput drug screening in terms of tumour physiology and ease of scale up is evaluated.

Molecular docking and molecular dynamics of hypoxia-inducible factor (HIF-1alpha): towards potential inhibitors

HIF-1α is a primary regulator in the adaptation of cancer cells to hypoxia. The aim was to find out new inhibitors of the HIF-1α. A molecular dynamic (MD) simulation performed on HIF-1α showed stable dynamic features. Virtual screening of 217 anticancer drugs was performed along with a positive control (2-Methoxyestradiolm, 2-ME2) on an optimized HIF-1α and dynamically simulated structure. Docking results produced two compounds namely pycnidione and nilotinib of high binding affinity -9.34 kcal/mol and -9.04 kcal/mol respectively, whereas 2-ME2 displayed a relatively lower affinity (-6.68 kcal/mol). For the three complexes, MD of 200 ns simulation was run. Data analysis showed that the three medications behaved similarly in the MD simulation. Nilotinib had a lower RMSD and higher SASA than the other complexes. In addition, the Nilotinib-HIF-1α combination had a lower RMSF value, a flatter Rg, and a number of hydrogen bonds similar to other complexes. MM-GBSA analysis revealed that nilotinib, pycnidione and 2-ME2 compounds had free binding energy of -23.77 ± 5.29, -21.85 ± 4.24 and -7.53 ± 6.62 kcal/mol respectively. Nilotinib and pycnidione bind competitively to HIF-1α, with nilotinib showing consistent molecular-dynamic properties. They relatively pass the blood-brain barrier, non-carcinogenic, and have IV-category acute oral toxicity. They have low CYP inhibitory characteristics. Further investigations are therefore warranted to elucidate their implications in hypoxia pathways, cell proliferation, apoptosis, survival, and metastatic potential.

Atypical chemokine receptor 2 expression is directly regulated by hypoxia inducible factor-1 alpha in cancer cells under hypoxia

Lack of significant and durable clinical benefit from anti-cancer immunotherapies is partly due to the failure of cytotoxic immune cells to infiltrate the tumor microenvironment. Immune infiltration is predominantly dependent on the chemokine network, which is regulated in part by chemokine and atypical chemokine receptors. We investigated the impact of hypoxia in the regulation of Atypical Chemokine Receptor 2 (ACKR2), which subsequently regulates major pro-inflammatory chemokines reported to drive cytotoxic immune cells into the tumor microenvironment. Our in silico analysis showed that both murine and human ACKR2 promoters contain hypoxia response element (HRE) motifs. Murine and human colorectal, melanoma, and breast cancer cells overexpressed ACKR2 under hypoxic conditions in a HIF-1α dependent manner; as such overexpression was abrogated in melanoma cells expressing non-functional deleted HIF-1α. We also showed that decreased expression of ACKR2 in HIF-1α-deleted cells under hypoxia was associated with increased CCL5 levels. Chromatin immunoprecipitation data confirmed that ACKR2 is directly regulated by HIF-1α at its promoter in B16-F10 melanoma cells. This study provides new key elements on how hypoxia can impair immune infiltration in the tumor microenvironment.

A Novel Pancreatic Cancer Hypoxia Status Related Gene Signature for Prognosis and Therapeutic Responses

Pancreatic cancer (PAC) is a highly fatal and aggressive type of cancer. Hypoxia is a common feature of PAC. The aim of this study was to develop a hypoxia status-related prognostic model for predicting the survival outcomes in PAC. The data sets of PAC from The Cancer Genome Atlas and the International Cancer Genome Consortium were used to construct and validate the signature. A 6 hypoxia status-related differential expression genes prognostic model for predicting the survival outcomes was established. The Kaplan-Meier analysis and Received operating characteristic curve indicated the good performance of the signature at predicting overall survival. Univariate and Multivariate Cox regression revealed that the signature was an independent prognostic factor in PAC. Weighted Gene Co-expression Network Analysis and immune infiltration analysis indicated that Immune-related pathways and immune cell infiltration was mostly enriched in the low-risk group, which presented a better prognosis. We also evaluated the predictive of the signature for immunotherapy and chemoradiotherapy. Risk gene LY6D may be a potential prognostic predictor of PAC. This model can be used as an independent prognostic factor for predicting clinical outcomes and a possible classifier for response to chemotherapy.

Making the Brightest Ones Dim: Maximizing the Photothermal Conversion Efficiency of BODIPY-Based Photothermal Agents

The successful implementation of photothermal therapy (PTT) in cancer treatment hinges on the development of highly effective photothermal agents (PTAs). Boron dipyrromethene (BODIPY) dyes, being well known for their high brightness and quantum efficiencies, are the antithesis of PTAs. Nonetheless, a systematic exploration of the photophysics and photothermal characteristics of a series of π-extended BODIPY dyes with high absorptivity in the near-infrared (NIR) region has achieved superior photothermal conversion efficiencies (>90%), in both monomeric state and nanoparticles after encapsulation in a biocompatible polyethyleneglycol 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy-(polyethylene glycol)-2000]. Optimal PTA candidates combine strong NIR absorption provided by extended donor-acceptor conjugation and an optimization of the electronic and steric effects of meso-substituents to maximize photothermal conversion performance. The PTT-optimized meso-CF3-BODIPY, TCF3PEn exhibits exceptional efficacy in inducing cancer cell apoptosis and in vivo tumor ablation using low-power NIR laser irradiation (0.3 W cm-2, 808 nm) as well as excellent biological safety, underscoring its potential for advancing light-induced cancer therapies.

Hodgkin lymphoma: hypodense lesions in mediastinal masses

Hypodense volumes (HDV) in mediastinal masses can be visualized in a computed tomography scan in Hodgkin lymphoma. We analyzed staging CT scans of 1178 patients with mediastinal involvement from the EuroNet-PHL-C1 trial and explored correlations of HDV with patient characteristics, mediastinal tumor volume and progression-free survival. HDV occurred in 350 of 1178 patients (29.7%), typically in larger mediastinal volumes. There were different patterns in appearance with single lesions found in 243 patients (69.4%), multiple lesions in 107 patients (30.6%). Well delineated lesions were found in 248 cases (70.1%), diffuse lesions were seen in 102 cases (29.1%). Clinically, B symptoms occurred more often in patients with HDV (47.7% compared to 35.0% without HDV (p = 0.039)) and patients with HDV tended to be in higher risk groups. Inadequate overall early-18F-FDG-PET-response was strongly correlated with the occurrence of hypodense lesions (p < 0.001). Patients with total HDV > 40 ml (n = 80) had a 5 year PFS of 79.6% compared to 89.7% (p = 0.01) in patients with HDV < 40 ml or no HDV. This difference in PFS is not caused by treatment group alone. HDV is a common phenomenon in HL with mediastinal involvement.

Oxygen Imaging of a Rabbit Tumor Using a Human-Sized Pulse Electron Paramagnetic Resonance Imager

PURPOSE

Spatial heterogeneity in tumor hypoxia is one of the most important factors regulating tumor growth, development, aggressiveness, metastasis, and affecting treatment outcome. Most solid tumors are known to have hypoxia or low oxygen levels (pO2 ≤10 torr). Electron paramagnetic resonance oxygen imaging (EPROI) is an emerging oxygen mapping technology. EPROI utilizes the linear relationship between the relaxation rates of the injectable OX071 trityl spin probe and the partial oxygen pressure (pO2). However, most of the EPROI studies have been limited to mouse models of solid tumors because of the instrument-size limitations. The purpose of this work was to develop a human-sized 9-mT (250 MHz resonance frequency, 60 cm bore size) pulse EPROI instrument and evaluate its performance with rabbit VX-2 tumor oxygen imaging.

METHODS

A New Zealand white rabbit with a 3.2-cm VX-2 tumor in the calf muscle was imaged using the human-sized EPROI instrument and a 2.25-in. ID volume coil. The animal received a ~8-min intravenous injection of OX071 (5.2 mL total volume at 72 mM concentration) and, after 75 min, an intratumoral injection (120 μL total at 5 mM OX071 concentration) and underwent EPROI. At the end of the experiments, MRI was performed using a preclinical 9.4-T MRI system to outline the tumor boundaries.

RESULTS

For the first time, a human-sized pulse EPROI instrument with a 60-cm bore size/250-MHz frequency was built and evaluated using rabbit tumor oxygen imaging. For the first time, the systemic IV injection of the oxygen-sensitive trityl OX071 spin probe was used for an animal of this size. The resulting EPROI image from the IV injection showed complete tumor coverage. The image obtained after intratumoral injection showed localized coverage in the upper lobe of the tumor, demonstrating the need for improved intratumoral injection protocol.

CONCLUSIONS

This study demonstrates the performance of the world's first human-sized pulse EPROI instrument. It also demonstrates that the EPROI of larger animals can be performed using the systemic injection of a manageable amount of the spin probe. This brings EPROI one step closer to clinical applications in cancer therapies. Oxygen imaging is a platform technology, and the instrument and techniques developed here will also be useful for other clinical applications.

Ferroptosis: a critical mechanism of N6-methyladenosine modification involved in carcinogenesis and tumor progression

Ferroptosis is an iron-dependent regulatory cell necrosis induced by iron overload and lipid peroxidation. It occurs when multiple redox-active enzymes are ectopically expressed or show abnormal function. Hence, the precise regulation of ferroptosis-related molecules is mediated across multiple levels, including transcriptional, posttranscriptional, translational, and epigenetic levels. N6-methyladenosine (m6A) is a highly evolutionarily conserved epigenetic modification in mammals. The m6A modification is commonly linked to tumor proliferation, progression, and therapy resistance because it is involved in RNA metabolic processes. Intriguingly, accumulating evidence suggests that dysregulated ferroptosis caused by the m6A modification drives tumor development. In this review, we summarized the roles of m6A regulators in ferroptosis-mediated malignant tumor progression and outlined the m6A regulatory mechanism involved in ferroptosis pathways. We also analyzed the potential value and application strategies of targeting m6A/ferroptosis pathway in the clinical diagnosis and therapy of tumors.

Enhancement of Tumor Perfusion and Antiangiogenic Therapy in Murine Models of Clear Cell Renal Cell Carcinoma Using Ultrasound-Stimulated Microbubbles

OBJECTIVE

To explore the effect of ultrasound-stimulated microbubble cavitation (USMC) on enhancing antiangiogenic therapy in clear cell renal cell carcinoma.

MATERIALS AND METHODS

We explored the effects of USMC with different mechanical indices (MIs) on tumor perfusion, 36 786-O tumor-bearing nude mice were randomly assigned into four groups: (i) control group, (ii) USMC0.25 group (MI = 0.25), (iii) USMC1.4 group (MI = 1.4) (iv) US1.4 group (MI = 1.4). Tumor perfusion was assessed by contrast-enhanced ultrasound (CEUS) before the USMC treatment and 30 min, 4h and 6h after the USMC treatment, respectively. Then we evaluated vascular normalization(VN) induced by low-MI (0.25) USMC treatment, 12 tumor-bearing nude mice were randomly divided into two groups: (i) control group (ii) USMC0.25 group. USMC treatment was performed, and tumor microvascular imaging and blood perfusion were analyzed by MicroFlow imaging (MFI) and CEUS 30 min after each treatment. In combination therapy, a total of 144 tumor-bearing nude mice were randomly assigned to six groups (n = 24): (i) control group, (ii) USMC1.4 group, (iii) USMC0.25 group, (iv) bevacizumab(BEV) group, (v) USMC1.4 +BEV group, (vi) USMC0.25 +BEV group. BEV was injected on the 6th, 10th, 14th, and 18th d after the tumors were inoculated, while USMC treatment was performed 24 h before and after every BEV administration. We examined the effects of the combination therapy through a series of experiments.

RESULTS

Tumor blood perfusion enhanced by USMC with low MI (0.25)could last for more than 6h, inducing tumor VN and promoting drug delivery. Compared with other groups, USMC0.25+BEV combination therapy had the strongest inhibition on tumor growth, led to the longest survival time of the mice.

CONCLUSION

The optimized USMC is a promising therapeutic approach that can be combined with antiangiogenic therapy to combat tumor progression.

Apigenin 7-glucoside impedes hypoxia-induced malignant phenotypes of cervical cancer cells in a p16-dependent manner

Apigenin 7-glucoside (A7G) can suppress cell proliferation and trigger apoptosis in cervical cancer cells. Considering that hypoxia is associated with the malignant phenotypes in cervical cancer, this study aimed to uncover whether A7G exhibits suppressive effects on the hypoxia-induced malignant phenotype of cervical cancer cells (HeLa cells). Compared to normoxia, hypoxia can enhance the malignant phenotypes of HeLa cells, including cell proliferation, reduced sensitivity against chemotherapeutic agents (oxaliplatin and paclitaxel), cancer stemness, migration, and invasion. A7G intervention (20, 40, and 60 μM) could impair these malignant phenotypes of HeLa cells and upregulate the expression level of total and nuclear p16 proteins. Molecular docking analysis showed the interaction between anion exchanger 1 and A7G. In p16-silencing HeLa cells, the anticancer effects of A7G were absent. Therefore, hypoxia derives malignant phenotypes of HeLa cells, which could be impeded by A7G in a p16-dependent manner.

Augmentation of tumour perfusion by ultrasound and microbubbles: A preclinical study

BACKGROUND

Hypoperfusion and the resulting hypoxia in solid tumours are critical causes of treatment resistance. Ultrasound-stimulated microbubbles (USMB) enhance tumour perfusion in a mechanism named the "sononeoperfusion" effect, which may relieve tumour hypoperfusion and hypoxia. The aim of this study was to determine the optimal mechanical index (MI) and therapeutic ultrasound exposure time for the sononeoperfusion effect and preliminarily explore the mechanism of sononeoperfusion and its effect on tumours.

METHODS

A total of 155 mice bearing MC38 tumours were included in this study. A modified diagnostic ultrasound and microbubbles (Zhifuxian) was used for USMB treatment. Tumour perfusion was evaluated by contrast-enhanced ultrasound (CEUS) and Hoechst 33342. The therapeutic pulse was operated with MIs of 0.1 to 0.5. The ultrasound exposure time was set from 150 s to 600 s. Endothelial nitric oxide synthase (eNOS) inhibition and NO, ATP, and phospho-eNOS (p-eNOS) detection were performed to explore the mechanisms of sononeoperfusion. Hypoxia-inducible factor-1α (HIF-1α) and tumour oxygen partial pressure (pO2) represent hypoxic tumour conditions.

RESULTS

Tumour perfusion was increased after USMB treatment at MIs of 0.1-0.4 and ultrasound exposure times of 150 s to 600 s, with optimal augmentation achieved at an MI of 0.3 and ultrasound exposure time of 450 s. The mean fluorescence intensity of Hoechst 33342 after USMB treatment was stronger than that of the control group. Biochemical assays showed a significant increase in ATP, p-eNOS and NO after USMB treatment. PO2 in tumour tissue increased significantly after USMB treatment and was maintained for more than 20 min.

CONCLUSIONS

The best sononeoperfusion effect was obtained with an MI of 0.3 and an ultrasound exposure time of 450 s. The effect is most likely related to NO and ATP increases. The sononeoperfusion effect might be a novel way to ameliorate tumour hypoperfusion and hypoxia.

Recent advances in hypoxia-activated compounds for cancer diagnosis and treatment

Hypoxia, as a prevalent feature of solid tumors, is correlated with tumorigenesis, proliferation, and invasion, playing an important role in mediating the drug resistance and affecting the cancer treatment outcomes. Due to the distinct oxygen levels between tumor and normal tissues, hypoxia-targeted therapy has attracted significant attention. The hypoxia-activated compounds mainly depend on reducible organic groups including azo, nitro, N-oxides, quinones and azide as well as some redox-active metal complex that are selectively converted into active species by the increased reduction potential under tumor hypoxia. In this review, we briefly summarized our current understanding on hypoxia-activated compounds with a particular highlight on the recently developed prodrugs and fluorescent probes for tumor treatment and diagnosis. We have also discussed the challenges and perspectives of small molecule-based hypoxia-activatable prodrug for future development.

The analysis of multiple omics and examination of pathological images revealed the prognostic and therapeutic significances of CD93 in lung squamous cell carcinoma

As a potent pro-angiogenic factor, the role of CD93 in the prognosis and therapeutic outcomes of lung squamous cell carcinoma (LUSC) merits exploration. In this study, we systematically collected transcriptomic, genomic, and clinical data from various public databases, as well as pathological images from hospital-operated patients. Employing statistical analysis software like R (Version 4.2.2) and GraphPad (Version 8.0), we conducted comprehensive analyses of multi-omics data. The results revealed elevated CD93 expression in LUSC tissues, closely associated with various cancer-related pathways. High CD93 expression indicated advanced clinical stage and poorer prognosis. Furthermore, CD93 contributed to resistance against chemotherapy and immunotherapy by enhancing tumor cell stemness, reducing immune cell infiltration, and inducing T cell exhaustion. Patients with low CD93 expression exhibited higher response rates to both chemotherapy and immunotherapy. Immunohistochemistry validated the significance of CD93 in LUSC. CD93 emerges as a biomarker signaling unfavorable prognosis and influencing therapeutic outcomes, suggesting a potential LUSC treatment avenue.

Associations between HIFs and tumor immune checkpoints: mechanism and therapy

Hypoxia, which activates a variety of signaling pathways to enhance tumor cell growth and metabolism, is among the primary features of tumor cells. Hypoxia-inducible factors (HIFs) have a substantial impact on a variety of facets of tumor biology, such as epithelial-mesenchymal transition, metabolic reprogramming, angiogenesis, and improved radiation resistance. HIFs induce hypoxia-adaptive responses in tumor cells. Many academics have presented preclinical and clinical research targeting HIFs in tumor therapy, highlighting the potential applicability of targeted HIFs. In recent years, the discovery of numerous pharmacological drugs targeting the regulatory mechanisms of HIFs has garnered substantial attention. Additionally, HIF inhibitors have attained positive results when used in conjunction with traditional oncology radiation and/or chemotherapy, as well as with the very promising addition of tumor immunotherapy. Immune checkpoint inhibitors (CPIs), which are employed in a range of cancer treatments over the past decades, are essential in tumor immunotherapy. Nevertheless, the use of immunotherapy has been severely hampered by tumor resistance and treatment-related toxicity. According to research, HIF inhibitors paired with CPIs may be game changers for multiple malignancies, decreasing malignant cell plasticity and cancer therapy resistance, among other things, and opening up substantial new pathways for immunotherapy drug development. The structure, activation mechanisms, and pharmacological sites of action of the HIF family are briefly reviewed in this work. This review further explores the interactions between HIF inhibitors and other tumor immunotherapy components and covers the potential clinical use of HIF inhibitors in combination with CPIs.

Exploration and validation of a combined Hypoxia and m6A/m5C/m1A regulated gene signature for prognosis prediction of liver cancer

BACKGROUND

It is widely acknowledged that hypoxia and m6A/m5C/m1A RNA modifications promote the occurrence and development of tumors by regulating the tumor microenvironment. This study aimed to establish a novel liver cancer risk signature based on hypoxia and m6A/m5C/m1A modifications.

METHODS

We collected data from The Cancer Genome Atlas (TCGA-LIHC), the National Omics Data Encyclopedia (NODE-HCC), the International Cancer Genome Consortium (ICGC), and the Gene Expression Omnibus (GEO) databases for our study (GSE59729, GSE41666). Using Cox regression and least absolute shrinkage and selection operator (LASSO) method, we developed a risk signature for liver cancer based on differentially expressed genes related to hypoxia and genes regulated by m6A/m5C/m1A modifications. We stratified patients into high- and low-risk groups and assessed differences between these groups in terms of gene mutations, copy number variations, pathway enrichment, stemness scores, immune infiltration, and predictive capabilities of the model for immunotherapy and chemotherapy efficacy.

RESULTS

Our analysis revealed a significantly correlated between hypoxia and methylation as well as m6A/m5C/m1A RNA methylation. The three-gene prognosis signature (CEP55, DPH2, SMS) combining hypoxia and m6A/m5C/m1A regulated genes exhibited strong predictive performance in TCGA-LIHC, NODE-HCC, and ICGC-LIHC-JP cohorts. The low-risk group demonstrated a significantly better overall survival compared to the high-risk group (p < 0.0001 in TCGA, p = 0.0043 in NODE, p = 0.0015 in ICGC). The area under the curve (AUC) values for survival at 1, 2, and 3 years are all greater than 0.65 in the three cohorts. Univariate and Multivariate Cox regression analyses of the three datasets indicated that the signature could serve as an independent prognostic predictor (p < 0.001 in the three cohorts). The high-risk group exhibited more genome changes and higher homologous recombination deficiency scores and stemness scores. Analysis of immune infiltration and immune activation confirmed that the signature was associated with various immune microenvironment characteristics. Finally, patients in the high-risk group experienced a more favorable response to immunotherapy, and various common chemotherapy drugs.

CONCLUSION

Our prognostic signature which integrates hypoxia and m6A/m5C/m1A-regulated genes, provides valuable insights for clinical prediction and treatment guidance for liver cancer patients.

Nanomedicine Strategies in Conquering and Utilizing the Cancer Hypoxia Environment

Cancer with a complex pathological process is a major disease to human welfare. Due to the imbalance between oxygen (O2) supply and consumption, hypoxia is a natural characteristic of most solid tumors and an important obstacle for cancer therapy, which is closely related to tumor proliferation, metastasis, and invasion. Various strategies to exploit the feature of tumor hypoxia have been developed in the past decade, which can be used to alleviate tumor hypoxia, or utilize the hypoxia for targeted delivery and diagnostic imaging. The strategies to alleviate tumor hypoxia include delivering O2, in situ O2 generation, reprogramming the tumor vascular system, decreasing O2 consumption, and inhibiting HIF-1 related pathways. On the other side, hypoxia can also be utilized for hypoxia-responsive chemical construction and hypoxia-active prodrug-based strategies. Taking advantage of hypoxia in the tumor region, a number of methods have been applied to identify and keep track of changes in tumor hypoxia. Herein, we thoroughly review the recent progress of nanomedicine strategies in both conquering and utilizing hypoxia to combat cancer and put forward the prospect of emerging nanomaterials for future clinical transformation, which hopes to provide perspectives in nanomaterials design.

A fully 3D-printed versatile tumor-on-a-chip allows multi-drug screening and correlation with clinical outcomes for personalized medicine

Optimal clinical outcomes in cancer treatments could be achieved through the development of reliable, precise ex vivo tumor models that function as drug screening platforms for patient-targeted therapies. Microfluidic tumor-on-chip technology is emerging as a preferred tool since it enables the complex set-ups and recapitulation of the physiologically relevant physical microenvironment of tumors. In order to overcome the common hindrances encountered while using this technology, a fully 3D-printed device was developed that sustains patient-derived multicellular spheroids long enough to conduct multiple drug screening tests. This tool is both cost effective and possesses four necessary characteristics of effective microfluidic devices: transparency, biocompatibility, versatility, and sample accessibility. Compelling correlations which demonstrate a clinical proof of concept were found after testing and comparing different chemotherapies on tumor spheroids, derived from ten patients, to their clinical outcomes. This platform offers a potential solution for personalized medicine by functioning as a predictive drug-performance tool.

Nanoprobe-based molecular imaging for tumor stratification

The responses of patients to tumor therapies vary due to tumor heterogeneity. Tumor stratification has been attracting increasing attention for accurately distinguishing between responders to treatment and non-responders. Nanoprobes with unique physical and chemical properties have great potential for patient stratification. This review begins by describing the features and design principles of nanoprobes that can visualize specific cell types and biomarkers and release inflammatory factors during or before tumor treatment. Then, we focus on the recent advancements in using nanoprobes to stratify various therapeutic modalities, including chemotherapy, radiotherapy (RT), photothermal therapy (PTT), photodynamic therapy (PDT), chemodynamic therapy (CDT), ferroptosis, and immunotherapy. The main challenges and perspectives of nanoprobes in cancer stratification are also discussed to facilitate probe development and clinical applications.

Nanomedicine Strategies for Targeting Tumor Stroma

The tumor stroma, or the microenvironment surrounding solid tumors, can significantly impact the effectiveness of cancer therapies. The tumor microenvironment is characterized by high interstitial pressure, a consequence of leaky vasculature, and dense stroma created by excessive deposition of various macromolecules such as collagen, fibronectin, and hyaluronic acid (HA). In addition, non-cancerous cells such as cancer-associated fibroblasts (CAFs) and the extracellular matrix (ECM) itself can promote tumor growth. In recent years, there has been increased interest in combining standard cancer treatments with stromal-targeting strategies or stromal modulators to improve therapeutic outcomes. Furthermore, the use of nanomedicine, which can improve the delivery and retention of drugs in the tumor, has been proposed to target the stroma. This review focuses on how different stromal components contribute to tumor progression and impede chemotherapeutic delivery. Additionally, this review highlights recent advancements in nanomedicine-based stromal modulation and discusses potential future directions for developing more effective stroma-targeted cancer therapies.

Effect of Anesthetic Carrier Gas on In Vivo Circulation Times of Intravenously Administered Phospholipid Oxygen Microbubbles in Rats

OBJECTIVE

For the treatment of tumor hypoxia, microbubbles comprising oxygen as a majority component of the gas core with a stabilizing shell may be used to deliver and release oxygen locally at the tumor site through ultrasound destruction. Previous work has revealed differences in circulation half-life in vivo for perfluorocarbon-filled microbubbles, typically used as ultrasound imaging contrast agents, as a function of anesthetic carrier gas. These differences in circulation time in vivo were likely due to gas diffusion as a function of anesthetic carrier gas, among other variables. This work has motivated studies to evaluate the effect of anesthetic carrier gas on oxygen microbubble circulation dynamics.

METHODS

Circulation time for oxygen microbubbles was derived from ultrasound image intensity obtained during longitudinal kidney imaging. Studies were constructed for rats anesthetized on inhaled isoflurane with either pure oxygen or medical air as the anesthetic carrier gas.

RESULTS

Results indicated that oxygen microbubbles were highly visible via contrast-specific imaging. Marked signal enhancement and duration differences were observed between animals breathing air and oxygen. Perhaps counterintuitively, oxygen microbubbles disappeared from circulation significantly faster when the animals were breathing pure oxygen compared with medical air. This may be explained by nitrogen counterdiffusion from blood into the bubble, effectively changing the gas composition of the core, as has been observed in perfluorocarbon core microbubbles.

CONCLUSION

Our findings suggest that the apparent longevity and persistence of oxygen microbubbles in circulation may not be reflective of oxygen delivery when the animal is anesthetized breathing air.

Harnessing Nanomaterials for Cancer Sonodynamic Immunotherapy

Immunotherapy has made remarkable strides in cancer therapy over the past decade. However, such emerging therapy still suffers from the low response rates and immune-related adverse events. Various strategies have been developed to overcome these serious challenges. Therein, sonodynamic therapy (SDT), as a non-invasive treatment, has received ever-increasing attention especially in the treatment of deep-seated tumors. Significantly, SDT can effectively induce immunogenic cell death to trigger systemic anti-tumor immune response, termed sonodynamic immunotherapy. The rapid development of nanotechnology has revolutionized SDT effects with robust immune response induction. As a result, more and more innovative nanosonosensitizers and synergistic treatment modalities are established with superior efficacy and safe profile. In this review, the recent advances in cancer sonodynamic immunotherapy are summarized with a particular emphasis on how nanotechnology can be explored to harness SDT for amplifying anti-tumor immune response. Moreover, the current challenges in this field and the prospects for its clinical translation are also presented. It is anticipated that this review can provide rational guidance and facilitate the development of nanomaterials-assisted sonodynamic immunotherapy, helping to pave the way for next-generation cancer therapy and eventually achieve a durable response in patients.

Technical development and validation of a clinically applicable microenvironment classifier as a biomarker of tumour hypoxia for soft tissue sarcoma

BACKGROUND

Soft tissue sarcomas (STS) are rare, heterogeneous tumours and biomarkers are needed to inform management. We previously derived a prognostic tumour microenvironment classifier (24-gene hypoxia signature). Here, we developed/validated an assay for clinical application.

METHODS

Technical performance of targeted assays (Taqman low-density array, nanoString) was compared in 28 prospectively collected formalin-fixed, paraffin-embedded (FFPE) biopsies. The nanoString assay was biologically validated by comparing to HIF-1α/CAIX immunohistochemistry (IHC) in clinical samples. The Manchester (n = 165) and VORTEX Phase III trial (n = 203) cohorts were used for clinical validation. The primary outcome was overall survival (OS).

RESULTS

Both assays demonstrated excellent reproducibility. The nanoString assay detected upregulation of the 24-gene signature under hypoxia in vitro, and 16/24 hypoxia genes were upregulated in tumours with high CAIX expression in vivo. Patients with hypoxia-high tumours had worse OS in the Manchester (HR 3.05, 95% CI 1.54-5.19, P = 0.0005) and VORTEX (HR 2.13, 95% CI 1.19-3.77, P = 0.009) cohorts. In the combined cohort, it was independently prognostic for OS (HR 2.24, 95% CI 1.42-3.53, P = 0.00096) and associated with worse local recurrence-free survival (HR 2.17, 95% CI 1.01-4.68, P = 0.04).

CONCLUSIONS

This study comprehensively validates a microenvironment classifier befitting FFPE STS biopsies. Future uses include: (1) selecting high-risk patients for perioperative chemotherapy; and (2) biomarker-driven trials of hypoxia-targeted therapies.

MRI-Based Tumor Necrosis Depiction in Pancreatic Ductal Adenocarcinoma: Can It Predict Tumor Aggressiveness?

The purpose of this study was to investigate whether tumor necrosis depicted on contrast-enhanced abdominal MRI can predict tumor aggressiveness in pancreatic ductal adenocarcinoma (PDAC). In this retrospective analysis, we included 71 patients with pathology-proven PDAC who underwent contrast-enhanced MRI from 2006 to 2020. Assessment for the presence/absence of imaging detected necrosis was performed on T2-weighted and contrast-enhanced T1-weighted images. Primary tumor characteristics, regional lymphadenopathy, metastases, stage, and overall survival were analyzed. Fisher's exact and Mann-Whitney U tests were used for statistical analysis. Of the 72 primary tumors, necrosis was identified on MRI in 58.3% (42/72). Necrotic PDACs were larger (44.6 vs. 34.5 mm, p = 0.0016), had higher rates of regional lymphadenopathy (69.0% vs. 26.7%, p = 0.0007), and more frequent metastases (78.6% vs. 40.0%, p = 0.0010) than those without MRI-evident necrosis. A non-statistically significant reduction in median overall survival was observed in patients with versus without MRI-evident necrosis (15.8 vs. 38.0 months, p = 0.23). PDAC tumor necrosis depicted on MRI was associated with larger tumors and higher frequency of regional lymphadenopathy and metastases.

A self-charging salt water battery for antitumor therapy

Implantable devices on the tumor tissue as a local treatment are able to work in situ, which minimizes systemic toxicities and adverse effects. Here, we demonstrated an implantable self-charging battery that can regulate tumor microenvironment persistently by the well-designed electrode redox reaction. The battery consists of biocompatible polyimide electrode and zinc electrode, which can consume oxygen sustainably during battery discharge/self-charge cycle, thus modulating hypoxia level in tumor microenvironment. The oxygen reduction in battery leads to the formation of reactive oxygen species, showing 100% prevention on tumor formation. Sustainable consumption of oxygen causes adequate intratumoral hypoxic conditions over the course of 14 days, which is helpful for the hypoxia-activated prodrugs (HAPs) to kill tumor cells. The synergistic effect of the battery/HAPs can deliver more than 90% antitumor rate. Using redox reactions in electrochemical battery provides a potential approach for the tumor inhibition and regulation of tumor microenvironment.

Hollow MnO2-Based Nanoprobes for Enhanced Photothermal/Photodynamic /Chemodynamic Co-Therapy of Hepatocellular Carcinoma

PURPOSE

The effect of monotherapy in cancer is frequently influenced by the tumor's unique hypoxic microenvironment, insufficient drug concentration at the treatment site, and tumour cells' increased drug tolerance. In this work, we expect to design a novel therapeutic nanoprobe with the ability to solve these problems and improve the efficacy of antitumor therapy.

METHODS

We have prepared a hollow manganese dioxide nanoprobes loaded with photosensitive drug IR780 for the photothermal/photodynamic/chemodynamic co-therapy of liver cancer.

RESULTS

The nanoprobe demonstrates efficient thermal transformation ability under a single laser irradiation, and under the synergistic influence of photo heat, accelerates the Fenton/ Fenton-like reaction efficiency based on Mn²⁺ ions to produce more ·OH under the synergistic effect of photo heat. Moreover, the oxygen released under the degradation of manganese dioxide further promotes the ability of photosensitive drugs to produce singlet oxygen (ROS). The nanoprobe has been found to efficiently destroy tumour cells in vivo and in vitro experiments when used in combination with photothermal/photodynamic/ chemodynamic modes of treatment under laser irradiation.

CONCLUSION

In all, this research shows that a therapeutic strategy based on this nanoprobe could be a viable alternative for cancer treatment in the near future.

EffectiveNess of a multimodal preHAbilitation program in patieNts with bladder canCEr undergoing radical cystectomy: protocol of the ENHANCE multicentre randomised controlled trial

INTRODUCTION

Radical cystectomy (RC) is the standard treatment for patients with non-metastatic muscle-invasive bladder cancer, as well as for patients with therapy refractory high-risk non-muscle invasive bladder cancer. However, 50-65% of patients undergoing RC experience perioperative complications. The risk, severity and impact of these complications is associated with a patient's preoperative cardiorespiratory fitness, nutritional and smoking status and presence of anxiety and depression. There is emerging evidence supporting multimodal prehabilitation as a strategy to reduce the risk of complications and improve functional recovery after major cancer surgery. However, for bladder cancer the evidence is still limited. The aim of this study is to investigate the superiority of a multimodal prehabilitation programme versus standard-of-care in terms of reducing perioperative complications in patients with bladder cancer undergoing RC.

METHODS AND ANALYSIS

This multicentre, open label, prospective, randomised controlled trial, will include 154 patients with bladder cancer undergoing RC. Patients are recruited from eight hospitals in The Netherlands and will be randomly (1:1) allocated to the intervention group receiving a structured multimodal prehabilitation programme of approximately 3-6 weeks, or to the control group receiving standard-of-care. The primary outcome is the proportion of patients who develop one or more grade ≥2 complications (according to the Clavien-Dindo classification) within 90 days of surgery. Secondary outcomes include cardiorespiratory fitness, length of hospital stay, health-related quality of life, tumour tissue biomarkers of hypoxia, immune cell infiltration and cost-effectiveness. Data collection will take place at baseline, before surgery and 4 and 12 weeks after surgery.

ETHICS AND DISSEMINATION

Ethical approval for this study was granted by the Medical Ethics Committee NedMec (Amsterdam, The Netherlands) under reference number 22-595/NL78792.031.22. Results of the study will be published in international peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05480735.

TIGIT signaling and its influence on T cell metabolism and immune cell function in the tumor microenvironment

One of the key challenges for successful cancer therapy is the capacity of tumors to evade immune surveillance. Tumor immune evasion can be accomplished through the induction of T cell exhaustion via the activation of various immune checkpoint molecules. The most prominent examples of immune checkpoints are PD-1 and CTLA-4. Meanwhile, several other immune checkpoint molecules have since been identified. One of these is the T cell immunoglobulin and ITIM domain (TIGIT), which was first described in 2009. Interestingly, many studies have established a synergistic reciprocity between TIGIT and PD-1. TIGIT has also been described to interfere with the energy metabolism of T cells and thereby affect adaptive anti-tumor immunity. In this context, recent studies have reported a link between TIGIT and the hypoxia-inducible factor 1-α (HIF1-α), a master transcription factor sensing hypoxia in several tissues including tumors that among others regulates the expression of metabolically relevant genes. Furthermore, distinct cancer types were shown to inhibit glucose uptake and effector function by inducing TIGIT expression in CD8+ T cells, resulting in an impaired anti-tumor immunity. In addition, TIGIT was associated with adenosine receptor signaling in T cells and the kynurenine pathway in tumor cells, both altering the tumor microenvironment and T cell-mediated immunity against tumors. Here, we review the most recent literature on the reciprocal interaction of TIGIT and T cell metabolism and specifically how TIGIT affects anti-tumor immunity. We believe understanding this interaction may pave the way for improved immunotherapy to treat cancer.

Hypoxic microenvironment in cancer: molecular mechanisms and therapeutic interventions

Having a hypoxic microenvironment is a common and salient feature of most solid tumors. Hypoxia has a profound effect on the biological behavior and malignant phenotype of cancer cells, mediates the effects of cancer chemotherapy, radiotherapy, and immunotherapy through complex mechanisms, and is closely associated with poor prognosis in various cancer patients. Accumulating studies have demonstrated that through normalization of the tumor vasculature, nanoparticle carriers and biocarriers can effectively increase the oxygen concentration in the tumor microenvironment, improve drug delivery and the efficacy of radiotherapy. They also increase infiltration of innate and adaptive anti-tumor immune cells to enhance the efficacy of immunotherapy. Furthermore, drugs targeting key genes associated with hypoxia, including hypoxia tracers, hypoxia-activated prodrugs, and drugs targeting hypoxia-inducible factors and downstream targets, can be used for visualization and quantitative analysis of tumor hypoxia and antitumor activity. However, the relationship between hypoxia and cancer is an area of research that requires further exploration. Here, we investigated the potential factors in the development of hypoxia in cancer, changes in signaling pathways that occur in cancer cells to adapt to hypoxic environments, the mechanisms of hypoxia-induced cancer immune tolerance, chemotherapeutic tolerance, and enhanced radiation tolerance, as well as the insights and applications of hypoxia in cancer therapy.

Low- dose Apatinib promotes vascular normalization and hypoxia reduction and sensitizes radiotherapy in lung cancer

BACKGROUND AND PURPOSE

Abnormal vascular network of tumor can create a hypoxic microenvironment, and reduce radiotherapy sensitivity. Normalization of tumor vasculature can be a new therapeutic strategy for sensitizing radiotherapy. This study aimed to explore the effect of apatinib on vascular normalization, as well as the syngeneic effect with radiotherapy on lung cancer.

MATERIALS AND METHODS

Lewis lung carcinoma (LLC) xenograft-bearing female C57BL/6 mice were treated with different doses of apatinib (30, 60, and 120 mg/kg per day) and/or radiation therapy (8 Gy/1F) and then sacrificed to harvest tumor tissue for immunohistochemical test. Further ¹⁸ F-FMISO micro- PET in vivo explored the degree of hypoxia.

RESULTS

Immunohistochemistry of CD31 and alpha-smooth muscle actin (α-SMA) proved that low-dose apatinib can normalize vasculature in tumor, especially on Day 10. Tissue staining of hypoxyprobe-1 and ¹⁸ F-FMISO micro- PET in vivo showed that 60 mg/kg/day of apatinib significantly alleviates hypoxia. Moreover, this study further proved that low-dose apatinib (60 mg/kg/day) can enhance the radio-response of LLC xenograft mice.

CONCLUSION

Our data suggested that low- dose apatinib can successfully induce a vascular normalization window and function as a radio- sensitizer in the lung cancer xenografts model.

Hypoxia signaling in cancer: Implications for therapeutic interventions

Hypoxia is a persistent physiological feature of many different solid tumors and a key driver of malignancy, and in recent years, it has been recognized as an important target for cancer therapy. Hypoxia occurs in the majority of solid tumors due to a poor vascular oxygen supply that is not sufficient to meet the needs of rapidly proliferating cancer cells. A hypoxic tumor microenvironment (TME) can reduce the effectiveness of other tumor therapies, such as radiotherapy, chemotherapy, and immunotherapy. In this review, we discuss the critical role of hypoxia in tumor development, including tumor metabolism, tumor immunity, and tumor angiogenesis. The treatment methods for hypoxic TME are summarized, including hypoxia-targeted therapy and improving oxygenation by alleviating tumor hypoxia itself. Hyperoxia therapy can be used to improve tissue oxygen partial pressure and relieve tumor hypoxia. We focus on the underlying mechanisms of hyperoxia and their impact on current cancer therapies and discuss the prospects of hyperoxia therapy in cancer treatment.

New Affordable Methods for Large-Scale Isolation of Major Olive Secoiridoids and Systematic Comparative Study of Their Antiproliferative/Cytotoxic Effect on Multiple Cancer Cell Lines of Different Cancer Origins

Olive oil phenols (OOPs) are associated with the prevention of many human cancers. Some of these have been shown to inhibit cell proliferation and induce apoptosis. However, no systematic comparative study exists for all the investigated compounds under the same conditions, due to difficulties in their isolation or synthesis. Herein are presented innovative methods for large-scale selective extraction of six major secoiridoids from olive oil or leaves enabling their detailed investigation. The cytotoxic/antiproliferative bioactivity of these six compounds was evaluated on sixteen human cancer cell lines originating from eight different tissues. Cell viability with half-maximal effective concentrations (EC50) was evaluated after 72 h treatments. Antiproliferative and pro-apoptotic effects were also assessed for the most bioactive compounds (EC50 ≤ 50 μM). Oleocanthal (1) showed the strongest antiproliferative/cytotoxic activity in most cancer cell lines (EC50: 9−20 μM). The relative effectiveness of the six OOPs was: oleocanthal (1) > oleuropein aglycone (3a,b) > ligstroside aglycone (4a,b) > oleacein (2) > oleomissional (6a,b,c) > oleocanthalic acid (7). This is the first detailed study comparing the bioactivity of six OOPs in such a wide array of cancer cell lines, providing a reference for their relative antiproliferative/cytotoxic effect in the investigated cancers.

The role of imaging in targeted delivery of nanomedicine for cancer therapy

Nanomedicines overcome the pharmacokinetic limitations of traditional drug formulations and have promising prospect in cancer treatment. However, nanomedicine delivery in vivo is still facing challenges from the complex physiological environment. For the purpose of effective tumor therapy, they should be designed to guarantee the five features principle, including long blood circulation, efficient tumor accumulation, deep matrix penetration, enhanced cell internalization and accurate drug release. To ensure the excellent performance of the designed nanomedicine, it would be better to monitor the drug delivery process as well as the therapeutic effects by real-time imaging. In this review, we summarize strategies in developing nanomedicines for efficiently meeting the five features of drug delivery, and the role of several imaging modalities (fluorescent imaging (FL), magnetic resonance imaging (MRI), computed tomography (CT), photoacoustic imaging (PAI), positron emission tomography (PET), and electron microscopy) in tracing drug delivery and therapeutic effect in vivo based on five features principle.

Hypoxia-Activated PEGylated Paclitaxel Prodrug Nanoparticles for Potentiated Chemotherapy

Developing controlled drug-release systems is imperative and valuable for increasing the therapeutic index. Herein, we synthesized hypoxia-responsive PEGylated (PEG = poly(ethylene glycol)) paclitaxel prodrugs by utilizing azobenzene (Azo) as a cleavable linker. The as-fabricated prodrugs could self-assemble into stable nanoparticles (PAP NPs) with high drug content ranging from 26 to 44 wt %. The Azo group in PAP NPs could be cleaved at the tumorous hypoxia microenvironment and promoted the release of paclitaxel for exerting cytotoxicity toward cancer cells. In addition, comparative researches revealed that the PAP NPs with the shorter methoxy-PEG chain (molecular weight = 750) possessed enhanced tumor suppression efficacy and alleviated off-target toxicity. Our work demonstrates a promising tactic to develop smart and simple nanomaterials for disease treatment.

Selection of RNA aptamers targeting hypoxia in cancer

Hypoxia plays a crucial role in tumorigenesis and drug resistance, and it is recognised as a major factor affecting patient clinical outcome. Therefore, the detection of hypoxic areas within the tumour micro-environment represents a useful way to monitor tumour growth and patients’ responses to treatments, properly guiding the choice of the most suitable therapy. To date, non-invasive hypoxia imaging probes have been identified, but their applicability in vivo is strongly limited due to an inadequate resistance to the low oxygen concentration and the acidic pH of the tumour micro-environment. In this regard, nucleic acid aptamers represent very powerful tools thanks to their peculiar features, including high stability to harsh conditions and a small size, resulting in easy and efficient tumour penetration. Here, we describe a modified cell-SELEX (Systematic Evolution of Ligands by EXponential enrichment) approach that allows the isolation of specific RNA aptamers for the detection of the hypoxic phenotype in breast cancer (BC) cells. We demonstrated the effectiveness of the proposed method in isolating highly stable aptamers with an improved and specific binding to hypoxic cells. To our knowledge, this is the first example of a cell-SELEX approach properly designed and modified to select RNA aptamers against hypoxia-related epitopes expressed on tumour cell surfaces. The selected aptamers may provide new effective tools for targeting hypoxic areas within the tumour with great clinical potential.

Suppression of Tumor Growth and Cell Migration by Indole-Based Benzenesulfonamides and Their Synergistic Effects in Combination with Doxorubicin

Pharmacological inhibition of the enzyme activity targeting carbonic anhydrases (CAs) demonstrated antiglaucoma and anticancer effects through pH control. Recently, we reported a series of indole-based benzenesulfonamides as potent CA inhibitors. The present study aimed to evaluate the antitumor effects of these compounds against various cancer cell lines, including breast cancer (MDA-MB-231, MCF-7, and SK-BR-3), lung cancer (A549), and pancreatic cancer (Panc1) cells. Overall, more potent cytotoxicity was observed on MCF-7 and SK-BR-3 cells than on lung or pancreatic cancer cells. Among the 15 compounds tested, A6 and A15 exhibited potent cytotoxic and antimigratory activities against MCF-7 and SK-BR-3 cells in the CoCl₂-induced hypoxic condition. While A6 and A15 markedly reduced the viability of control siRNA-treated cells, these compounds could not significantly reduce the viability of CA IX-knockdown cells, suggesting the role of CA IX in their anticancer activities. To assess whether these compounds exerted synergism with a conventional anticancer drug doxorubicin (DOX), the cytotoxic effects of A6 or A15 combined with DOX were analyzed using Chou−Talalay and Bliss independence methods. Our data revealed that both A6 and A15 significantly enhanced the anticancer activity of DOX. Among the tested pairs, the combination of DOX with A15 showed the strongest synergism on SK-BR-3 cells. Moreover, this combination further attenuated cell migration compared to the respective drug. Collectively, our results demonstrated that A6 and A15 suppressed tumor growth and cell migration of MCF-7 and SK-BR-3 cells through inhibition of CA IX, and the combination of these compounds with DOX exhibited synergistic cytotoxic effects on these breast cancer cells. Therefore, A6 and A15 may serve as potential anticancer agents alone or in combination with DOX against breast cancer.

Genetically engineered bacteria-mediated multi-functional nanoparticles for synergistic tumor-targeting therapy

Focused ultrasonic ablation surgery (FUAS) for tumor treatment has emerged as an effective non-invasive therapeutic approach, but its widespread clinical utilization is limited by its low therapeutic efficiency caused by inadequate tumor targeting, single imaging modality, and possible tumor recurrence following surgery. Therefore, this study aimed to develop a biological targeting synergistic system consisting of genetically engineered bacteria and multi-functional nanoparticles to overcome these limitations. Escherichia coli was genetically modified to carry an acoustic reporter gene encoding the formation of gas vesicles (GVs) and then target the tumor hypoxic environment in mice. After E. coli producing GVs (GVs-E. coli) colonized the tumor target area, ultrasound imaging and collaborative FUAS were performed; multi-functional nanoparticles were then enriched in the tumor target area through electrostatic adsorption. Multi-functional cationic lipid nanoparticles containing IR780, perfluorohexane, and banoxantrone dihydrochloride (AQ4N) were coloaded in the tumor to realize targeted multimodal imaging and enhance the curative effect of FUAS. AQ4N was stimulated by the tumor hypoxic environment and synergistically cooperated with FUAS to kill tumor cells. In sum, synergistic tumor therapy involving multi-functional nanoparticles mediated by genetically engineered bacteria overcomes the limitations and improves the curative effect of existing FUAS. STATEMENT OF SIGNIFICANCE: Inadequate tumor targeting, single image monitoring mode, and prone tumor recurrence following surgery remain significant challenges yet critical for tumor therapy. This study proposes a strategy for genetically engineered bacteria-mediated multifunctional nanoparticles for synergistic tumor therapy. The multifunctional genetically engineered biological targeting synergistic agent can accomplish tumor-targeting therapy, synergistic FUAS ablation, hypoxia-activated chemotherapy combined with FUAS ablation, and multiple-imaging guidance and monitoring all at the same time, thereby compensating for the shortcomings of FUAS treatment. This strategy could pave the way for the progress of tumor therapy.

Histological tumor necrosis in pancreatic cancer after neoadjuvant therapy

The pathological prognostic factors in pancreatic cancer patients who have received neoadjuvant therapy (NAT) are still elusive. The aim of the present study was to investigate the prognostic potential of histological tumor necrosis (HTN) in patients who received NAT and to evaluate tumor changes after NAT. HTN was studied in 44 pancreatic cancer patients who received NAT followed by surgery (NAT group) compared with 263 patients who received upfront surgery (UFS group). The prognostic factors in the NAT group were analyzed, and carbonic anhydrase 9 (CA‑9) expression was compared between the NAT and USF group to evaluate the hypoxic microenvironment changes during NAT. HTN was found in 15 of 44 patients in the NAT group, and its frequency was lower than that in the UFS group (34 vs. 51%, P=0.04). Cox proportional hazards models identified HTN as an independent risk factor for relapse‑free survival in the NAT group [risk ratio (RR), 5.60; 95% confidence interval (CI): 2.27‑14.26, P<0.01]. Significant correlations were found between HTN and CA‑9 expression both in the NAT and UFS groups (P<0.01 for both). CA‑9 expression was significantly upregulated in the NAT group overall, although this upregulation was specifically induced in patients without HTN. In conclusion, HTN was a poor prognostic factor in pancreatic cancer patients receiving NAT followed by surgery, and the present study suggests a close association between HTN and tumor hypoxia. Increased hypoxia after NAT may support the thesis for re‑engineering the hypoxia‑alleviating tumor microenvironment in NAT regimens for pancreatic cancer.

Effects of Ultrafine Single-Nanometer Oxygen Bubbles on Radiation Sensitivity in a Tumor-Bearing Mouse Model

Radiation therapy against cancer cells often causes radiation resistance via accumulation of hypoxia-inducible factor 1 subunit alpha (HIF-1α) under hypoxic conditions and severe side effects. Radiation sensitizers without side effects are required to overcome hypoxia-induced radiation resistance and decrease radiation-related side effects in patients with refractory cancer. We previously developed oxygen nanobubble water (NBO₂ water) and demonstrated that it suppresses hypoxia-induced radiation resistance in cancer cell lines within the single-nanometer range. This study aimed to elucidate whether NBO₂ water could act as a radiosensitizer via regulation of HIF-1α in a tumor-bearing mouse model. Six-week-old female BALB/c mice subcutaneously injected with tumor cells received control water or NBO₂ water for 28 days, after which biochemical examinations and radiation treatment were performed. Hypoxic tumor regions were detected immunohistochemically. We found that NBO₂ water sensitized radiation reactivity in the xenografted tumors. Notably, NBO₂ water administration downregulated the accumulation of HIF-1α in xenografted tumors and did not affect the vital organs of healthy mice. The combination of radiation and single-nanometer NBO₂ water without severe side effects may be a promising therapeutic option to improve radiation sensitivity in cancer patients without tolerance to invasive treatments.

Identification and validation of a prognostic signature related to hypoxic tumor microenvironment in cervical cancer

Background

Hypoxia is a common microenvironment condition in most malignant tumors and has been shown to be associated with adverse outcomes of cervical cancer patients. In this study, we investigated the effects of hypoxia-related genes on tumor progress to characterize the tumor hypoxic microenvironment.

Methods

We retrieved a set of hypoxia-related genes from the Molecular Signatures Database and evaluated their prognostic value for cervical cancer. A hypoxia-based prognostic signature for cervical cancer was then developed and validated using tumor samples from two independent cohorts (TCGA-CESC and CGCI-HTMCP-CC cohorts). Finally, we validated the hypoxia prediction of ccHPS score in eight human cervical cancer cell lines treated with the hypoxic and normoxic conditions, and 286 tumor samples with hypoxic category (more or less) from Gene Expression Omnibus (GEO) database with accession GSE72723.

Results

A risk signature model containing nine hypoxia-related genes was developed and validated in cervical cancer. Further analysis showed that this risk model could be an independent prognosis factor of cervical cancer, which reflects the condition of the hypoxic tumor microenvironment and its remodeling of cell metabolism and tumor immunity. Furthermore, a nomogram integrating the novel risk model and lymphovascular invasion status was developed, accurately predicting the 1-, 3- and 5-year prognosis with AUC values of 0.928, 0.916 and 0.831, respectively. These findings provided a better understanding of the hypoxic tumor microenvironment in cervical cancer and insights into potential new therapeutic strategies in improving cancer therapy.

HIF-1α Regulates the Progression of Cervical Cancer by Targeting YAP/TAZ

Cervical carcinoma is one of the serious pernicious cancers that influence women's health. Invasion and metastasis are the chief reason of poor prognosis of cervical carcinoma. Hypoxia-inducible factor-1α (HIF-1α) is a significant regulatory factor of intracellular oxygen supersession, and its expression or increased activity is closely related to the arise and expansion of various human tumors. However, the relationship between HIF-1α (hypoxia-inducible factor 1) and Hippo pathway target gene Yes-related protein (YAP) and transcriptional coactivator (TAZ) in cervical carcinoma remains unclear. Here, we studied the clinical correlation of HIF-1α and YAP/TAZ expression in normal tissues, cervical intraepithelial neoplasia (CIN), and cervical squamous cell carcinoma (CSCC). In order to analyze the role of HIF-1α in CCSC in vitro, SiHa cells with high expression of HIF-1α and C33a cells with low expression of HIF-1α were screened by detection. After transfection with lentivirus, HIF-1α levels were downregulated in SiHa cells and upregulated in C33a Cells, respectively. Then, the expression of HIF-1α in transfected cervical cancer cells Siha and C33a was detected by qRT-PCR and Western blot, and the expression of YAP/TAZ was detected in cervical squamous cell carcinoma cells after HIF-1α expression was altered. To explore HIF-1α role in cell proliferation, invasion, and metastasis, we examined the changes of cell function in cervical cancer cells with HIF-1α overexpression and inhibition by MTT assay, wound healing assay, Transwell test, and other cell function tests. At the same time, HIF-1α overexpression and HIF-1α inhibition cervical cancer cells were transplanted into nude mice, and tumors were isolated from the nude mice, and tumor volume and weight were observed. In conclusion, HIF-1α significantly promotes the proliferation, invasion, and migration of cervical carcinoma cells by upregulating YAP/TAZ. In addition, YAP/TAZ, the target gene of Hippo pathway, plays an important role in CCSC cells, pointing out that HIF-1α is provided with treatment potential for the treatment of CCSC.

Overcoming Hypoxia-Induced Drug Resistance via Promotion of Drug Uptake and Reoxygenation by Acousto–Mechanical Oxygen Delivery

Hypoxia-induced drug resistance (HDR) is a critical issue in cancer therapy. The presence of hypoxic tumor cells impedes drug uptake and reduces the cytotoxicity of chemotherapeutic drugs, leading to HDR and increasing the probability of tumor recurrence and metastasis. Microbubbles, which are used as an ultrasound contrast agent and drug/gas carrier, can locally deliver drugs/gas and produce an acousto–mechanical effect to enhance cell permeability under ultrasound sonication. The present study applied oxygen-loaded microbubbles (OMBs) to evaluate the mechanisms of overcoming HDR via promotion of drug uptake and reoxygenation. A hypoxic mouse prostate tumor cell model was established by hypoxic incubation for 4 h. After OMB treatment, the permeability of HDR cells was enhanced by 23 ± 5% and doxorubicin uptake was increased by 11 ± 7%. The 61 ± 14% reoxygenation of HDR cells increased the cytotoxicity of doxorubicin from 18 ± 4% to 58 ± 6%. In combination treatment with OMB and doxorubicin, the relative contributions of uptake promotion and reoxygenation towards overcoming HDR were 11 ± 7% and 28 ± 10%, respectively. Our study demonstrated that reoxygenation of hypoxic conditions is a critical mechanism in the inhibition of HDR and enhancing the outcome of OMB treatment.

Application of the anthraquinone drug rhein as an axial ligand in bifunctional Pt(IV) complexes to obtain antiproliferative agents against human glioblastoma cells

Octahedral Pt(IV) prodrugs are an effective way to combine cisplatin-like moieties and a second drug to obtain selective and stimuli responsive bifunctional antiproliferative compounds. Recently, two bifunctional Pt(IV) complexes have shown interesting in vitro and in vivo effects in glioblastoma, the most aggressive primary brain tumor. An interesting observation indicates that 4,5-dihydroxy-9,10-dioxo-9,10-dihydroanthracene-2-carboxylic acid (rhein) can inhibit in vivo glioma tumor progression. Furthermore, a prodrug in which cisplatin was combined with two molecules of rhein showed a potency higher than that of cisplatin toward cisplatin-resistant lung carcinoma cells. However, the high lipophilicity of this type of complex affects their solubility and bioavailability. To overcome these limits, in the present work, three Pt(IV) derivatives were obtained by differently linking one molecule of rhein and one acetato ligand at the axial position to a cisplatin core. The complexes proved to be similar to or more potent than the parent cisplatin and rhein, and the reference drug temozolomide on two human glioblastoma cell lines (U87-MG and T98G). They retained their activity under hypoxia and caused a significant reduction in the motility of both cell lines, which can be related to their ability to inhibit MMP2 and MMP9 matrix metalloproteinases. Finally, physicochemical and computational studies indicated that these Pt(IV) derivatives are more prone than rhein to cross the blood-brain barrier.

Non-conventional and Investigational PET Radiotracers for Breast Cancer: A Systematic Review

Breast cancer is one of the most common malignancies in women, with high morbidity and mortality rates. In breast cancer, the use of novel radiopharmaceuticals in nuclear medicine can improve the accuracy of diagnosis and staging, refine surveillance strategies and accuracy in choosing personalized treatment approaches, including radioligand therapy. Nuclear medicine thus shows great promise for improving the quality of life of breast cancer patients by allowing non-invasive assessment of the diverse and complex biological processes underlying the development of breast cancer and its evolution under therapy. This review aims to describe molecular probes currently in clinical use as well as those under investigation holding great promise for personalized medicine and precision oncology in breast cancer.