Hypoxic tumor microenvironment and cancer cell differentiation

Nuclear magnetic resonance-based lipid metabolite profiles for differentiation of patients with liver cirrhosis with and without hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma is frequently unrecognized in its early stage limiting the access to the first therapeutic steps resulting in a low cure rate. Therefore, an early diagnosis is crucial. In this scenario the analysis of lipidome and metabolome emerged as a promising tool for early detection.

AIMS

Aim of the study was to characterize metabolomic profiles as novel markers of early hepatocellular carcinoma.

METHODS

Serum basal levels of metabolites, isolated from a cohort of 90 patients (n = 30 early stage; n = 30 advanced stage; n = 30 liver cirrhosis) were analysed using a nuclear magnetic resonance spectroscopy platform. To assess the predictive value of nuclear magnetic resonance profiles, we included the magnetic resonance imaging follow up of control patients with liver cirrhosis.

RESULTS

Significant differences were observed in the levels of individual parameters that included total cholesterol, LDL and HDL subclasses, Isoleucine, Valine, Triglycerides, Lactate, Alanine, Albumin, alpha Fetoprotein, Dimethylamine, Glycerol, and total Bilirubin levels in cancer compared to liver cirrhosis (p < 0.05). Furthermore, a significant difference in glycerol levels (p < 0.05) and a decreasing trend in dimethylamine were observed in cirrhotic patients who later developed HCC (16%, n = 5). Retrospective MRI analysis revealed precursor lesions in 3/5 patients, initially not classified as HCC due to their size and hemodynamic features.

CONCLUSION

Nuclear magnetic resonance based assessment of lipidomic and metabolomic profiles permit the differentiation of cancer from liver cirrhosis. The data obtained suggests a possible role of lipidomic based serum profiles for early detection.

Recent trends and therapeutic potential of phytoceutical-based nanoparticle delivery systems in mitigating non-small cell lung cancer

Lung cancer is the leading cause of cancer death globally, with non-small cell lung cancer accounting for the majority (85%) of cases. Standard treatments including chemotherapy and radiotherapy present multiple adverse effects. Medicinal plants, used for centuries, are traditionally processed by methods such as boiling and oral ingestion, However, water solubility, absorption, and hepatic metabolism reduce phytoceutical bioavailability. More recently, isolated molecular compounds from these plants can be extracted with these phytoceuticals administered either individually or as an adjunct with standard therapy. Phytoceuticals have been shown to alleviate symptoms, may reduce dosage of chemotherapy and, in some cases, enhance pharmaceutical mechanisms. Research has identified many phytoceuticals' actions on cancer-associated pathways, such as oncogenesis, the tumour microenvironment, tumour cell proliferation, metastasis, and apoptosis. The development of novel nanoparticle delivery systems such as solid lipid nanoparticles, liquid crystalline nanoparticles, and liposomes has enhanced the bioavailability and targeted delivery of pharmaceuticals and phytoceuticals. This review explores the biological pathways associated with non-small cell lung cancer, a diverse range of phytoceuticals, the cancer pathways they act upon, and the pros and cons of several nanoparticle delivery systems.

Programmed death receptor (PD-)1/PD-ligand (L)1 in urological cancers : the "all-around warrior" in immunotherapy

Programmed death receptor-1 (PD-1) and its ligand, programmed death ligand-1 (PD-L1) are essential molecules that are key in modulating immune responses. PD-L1 is constitutively expressed on various immune cells, epithelial cells, and cancer cells, where it functions as a co-stimulatory molecule capable of impairing T-cell mediated immune responses. Upon binding to PD-1 on activated T-cells, the PD-1/PD-L1 interaction triggers signaling pathways that can induce T-cell apoptosis or anergy, thereby facilitating the immune escape of tumors. In urological cancers, including bladder cancer (BCa), renal cell carcinoma (RCC), and prostate cancer (PCa), the upregulation of PD-L1 has been demonstrated. It is linked to poor prognosis and enhanced tumor immune evasion. Recent studies have highlighted the significant role of the PD-1/PD-L1 axis in the immune escape mechanisms of urological cancers. The interaction between PD-L1 and PD-1 on T-cells further contributes to immunosuppression by inhibiting T-cell activation and proliferation. Clinical applications of PD-1/PD-L1 checkpoint inhibitors have shown promising efficacy in treating advanced urological cancers, significantly improving patient outcomes. However, resistance to these therapies, either intrinsic or acquired, remains a significant challenge. This review aims to provide a comprehensive overview of the role of the PD-1/PD-L1 signaling pathway in urological cancers. We summarize the regulatory mechanism underlying PD-1 and PD-L1 expression and activity, including genetic, epigenetic, post-transcriptional, and post-translational modifications. Additionally, we discuss current clinical research on PD-1/PD-L1 inhibitors, their therapeutic potential, and the challenges associated with resistance. Understanding these mechanisms is crucial for developing new strategies to overcome therapeutic limitations and enhance the efficacy of cancer immunotherapy.

Density Gradient Centrifugation Is an Effective Tool to Isolate Cancer Stem-like Cells from Hypoxic and Normoxia Triple-Negative Breast Cancer Models

Accumulating evidence has indicated that stemness-related genes are associated with the aggressiveness of triple-negative breast cancer (TNBC). Because no universal markers for breast CSCs are available, we applied the density gradient centrifugation method to enrich breast CSCs. We demonstrated that the density centrifugation method allows for the isolation of cancer stem cells (CSCs) from adherent and non-adherent MCF7 (Luminal A), MDA-MB-231 (TNBC) and MDA-MB-468 (TNBC) breast cancer cells. The current study shows that the CSCs' enriched fraction from Luminal A and TNBC cells have an increased capacity to grow anchorage-independently. CSCs from adherent TNBC are mainly characterized by metabolic plasticity, whereas CSCs from Luminal A have an increased mitochondrial capacity. Moreover, we found that non-adherent growth CSCs isolated from large mammospheres have a higher ability to grow anchorage-independently compared to CSCs isolated from small mammospheres. In CSCs, a metabolic shift towards glycolysis was observed due to the hypoxic environment of the large mammosphere. Using a bioinformatic analysis, we indicate that hypoxia HYOU1 gene overexpression is associated with the aggressiveness, metastasis and poor prognosis of TNBC. An in vitro study demonstrated that HYOU1 overexpression increases breast cancer cells' stemness and hyperactivates their metabolic activity. In conclusion, we show that density gradient centrifugation is a non-marker-based approach to isolate metabolically flexible (normoxia) CSCs and glycolytic (hypoxic) CSCs from aggressive TNBC.

Data-driven structural analysis of small cell lung cancer transcription factor network suggests potential subtype regulators and transition pathways

Small cell lung cancer (SCLC) is an aggressive disease and challenging to treat due to its mixture of transcriptional subtypes and subtype transitions. Transcription factor (TF) networks have been the focus of studies to identify SCLC subtype regulators via systems approaches. Yet, their structures, which can provide clues on subtype drivers and transitions, are barely investigated. Here, we analyze the structure of an SCLC TF network by using graph theory concepts and identify its structurally important components responsible for complex signal processing, called hubs. We show that the hubs of the network are regulators of different SCLC subtypes by analyzing first the unbiased network structure and then integrating RNA-seq data as weights assigned to each interaction. Data-driven analysis emphasizes MYC as a hub, consistent with recent reports. Furthermore, we hypothesize that the pathways connecting functionally distinct hubs may control subtype transitions and test this hypothesis via network simulations on a candidate pathway and observe subtype transition. Overall, structural analyses of complex networks can identify their functionally important components and pathways driving the network dynamics. Such analyses can be an initial step for generating hypotheses and can guide the discovery of target pathways whose perturbation may change the network dynamics phenotypically.

Smart Nanozymes for Cancer Therapy: The Next Frontier in Oncology

Nanomaterials that mimic the catalytic activity of natural enzymes in the complex biological environment of the human body are called nanozymes. Recently, nanozyme systems have been reported with diagnostic, imaging, and/or therapeutic capabilities. Smart nanozymes strategically exploit the tumor microenvironment (TME) by the in situ generation of reactive species or by the modulation of the TME itself to result in effective cancer therapy. This topical review focuses on such smart nanozymes for cancer diagnosis, and therapy modalities with enhanced therapeutic effects. The dominant factors that guide the rational design and synthesis of nanozymes for cancer therapy include an understanding of the dynamic TME, structure-activity relationships, surface chemistry for imparting selectivity, and site-specific therapy, and stimulus-responsive modulation of nanozyme activity. This article presents a comprehensive analysis of the subject including the diverse catalytic mechanisms of different types of nanozyme systems, an overview of the TME, cancer diagnosis, and synergistic cancer therapies. The strategic application of nanozymes in cancer treatment can well be a game changer in future oncology. Moreover, recent developments may pave the way for the deployment of nanozyme therapy into other complex healthcare challenges, such as genetic diseases, immune disorders, and ageing.

Recent Advances in Nanoplatform Construction Strategy for Alleviating Tumor Hypoxia

Hypoxia is a typical feature of most solid tumors and has important effects on tumor cells' proliferation, invasion, and metastasis. This is the key factor that leads to poor efficacy of different kinds of therapy including chemotherapy, radiotherapy, photodynamic therapy, etc. In recent years, the construction of hypoxia-relieving functional nanoplatforms through nanotechnology has become a new strategy to reverse the current situation of tumor microenvironment hypoxia and improve the effectiveness of tumor treatment. Here, the main strategies and recent progress in constructing nanoplatforms are focused on to directly carry oxygen, generate oxygen in situ, inhibit mitochondrial respiration, and enhance blood perfusion to alleviate tumor hypoxia. The advantages and disadvantages of these nanoplatforms are compared. Meanwhile, nanoplatforms based on organic and inorganic substances are also summarized and classified. Through the comprehensive overview, it is hoped that the summary of these nanoplatforms for alleviating hypoxia could provide new enlightenment and prospects for the construction of nanomaterials in this field.

A novel cross-communication of HIF-1α and HIF-2α with Wnt signaling in TNBC and influence of hypoxic microenvironment in the formation of an organ-on-chip model of breast cancer

The microenvironment role is very important in cancer development. The epithelial-mesenchymal transition of the cancer cells depends upon specific signaling and microenvironmental conditions, such as hypoxic conditions. The crosstalk between hypoxia and Wnt signaling through some molecular mechanism in TNBC is related. Cross-communication between hypoxia and Wnt signaling in cancer cells is known, but the detailed mechanism in TNBC is unknown. This review includes the role of the hypoxia microenvironment in TNBC and the novel crosstalk of the Wnt signaling and hypoxia. When targeted, the new pathway and crosstalk link may be a solution for metastatic TNBC and chemoresistance. The microenvironment influences cancer's metastasis, which changes from person to person. Therefore, organ-on-a-chip is a very novel model to test the drugs clinically before going for human trials, focusing on personalized medications can be done. The effect of the hypoxia microenvironment on breast cancer stem cells is still unknown. Apart from all the published papers, this paper mainly focuses only on the hypoxic microenvironment and its association with the growth of TNBC. The medicines or small proteins, drugs, mimics, and inhibitors targeting wnt and hypoxia genes are consolidated in this review paper.

miR-210-3p enriched extracellular vesicles from hypoxic neuroblastoma cells stimulate migration and invasion of target cells

BACKGROUND

Tumor hypoxia stimulates release of extracellular vesicles (EVs) that facilitate short- and long-range intercellular communication and metastatization. Albeit hypoxia and EVs release are known features of Neuroblastoma (NB), a metastasis-prone childhood malignancy of the sympathetic nervous system, whether hypoxic EVs can facilitate NB dissemination is unclear.

METHODS

Here we isolated and characterized EVs from normoxic and hypoxic NB cell culture supernatants and performed microRNA (miRNA) cargo analysis to identify key mediators of EVs biological effects. We then validated if EVs promote pro-metastatic features both in vitro and in an in vivo zebrafish model.

RESULTS

EVs from NB cells cultured at different oxygen tensions did not differ for type and abundance of surface markers nor for biophysical properties. However, EVs derived from hypoxic NB cells (hEVs) were more potent than their normoxic counterpart in inducing NB cells migration and colony formation. miR-210-3p was the most abundant miRNA in the cargo of hEVs; mechanistically, overexpression of miR-210-3p in normoxic EVs conferred them pro-metastatic features, whereas miR-210-3p silencing suppressed the metastatic ability of hypoxic EVs both in vitro and in vivo.

CONCLUSION

Our data identify a role for hypoxic EVs and their miR-210-3p cargo enrichment in the cellular and microenvironmental changes favoring NB dissemination.

Data-driven structural analysis of Small Cell Lung Cancer transcription factor network suggests potential subtype regulators and transition pathways

Small Cell Lung Cancer (SCLC) is an aggressive disease and challenging to treat due to its mixture of transcriptional subtypes and subtype transitions. Transcription factor (TF) networks have been the focus of studies to identify SCLC subtype regulators via systems approaches. Yet, their structures, which can provide clues on subtype drivers and transitions, are barely investigated. Here, we analyze the structure of an SCLC TF network by using graph theory concepts and identify its structurally important components responsible for complex signal processing, called hubs. We show that the hubs of the network are regulators of different SCLC subtypes by analyzing first the unbiased network structure and then integrating RNA-seq data as weights assigned to each interaction. Data-driven analysis emphasizes MYC as a hub, consistent with recent reports. Furthermore, we hypothesize that the pathways connecting functionally distinct hubs may control subtype transitions and test this hypothesis via network simulations on a candidate pathway and observe subtype transition. Overall, structural analyses of complex networks can identify their functionally important components and pathways driving the network dynamics. Such analyses can be an initial step for generating hypotheses and can guide the discovery of target pathways whose perturbation may change the network dynamics phenotypically.

AIPH-Encapsulated Thermo-Sensitive Liposomes for Synergistic Microwave Ablation and Oxygen-Independent Dynamic Therapy

Microwave ablation (MWA) is a novel treatment modality that can lead to the death of tumor cells by heating the ions and polar molecules in the tissue through high-speed vibration and friction. However, the single hyperthermia is not sufficient to completely inhibit tumor growth. Herein, a thermodynamic cancer-therapeutic modality has been fabricated which could be able to overcome hypoxia's limitations in the tumor microenvironment. Using thermo-sensitive liposomes (TSLs) and oxygen-independent radical generators (2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride [AIPH]), a nano-drug delivery system denoted as ATSL is developed for efficient sequential cancer treatment. Under the microwave field, the temperature rise of local tissue could not only lead to the damage of tumor cells but also induce the release of AIPH encapsulated in ATSL to produce free radicals, eliciting tumor cell death. In addition, the ATSL developed here would avoid the side effects caused by the uncontrolled diffusion of AIPH to normal tissues. The ATSLs have shown excellent therapeutic effects both in vitro and in vivo, suggesting its highly promising potential for clinic.

Essential amino acids as diagnostic biomarkers of hepatocellular carcinoma based on metabolic analysis

Metabolomics, defined as the comprehensive identification of all small metabolites in a biological sample, has the power to shed light on phenotypic changes associated with various diseases, including cancer. To discover potential metabolomic biomarkers of hepatocellular carcinoma (HCC), we investigated the metabolomes of tumor and non-tumor tissue in 20 patients with primary HCC using capillary electrophoresis-time-of-flight mass spectrometry. We also analyzed blood samples taken immediately before and 14 days after hepatectomy to identify associated changes in the serum metabolome. Marked changes were detected in the different quantity of 61 metabolites that could discriminate between HCC tumor and paired non-tumor tissue and additionally between HCC primary tumors and colorectal liver metastases. Among the 30 metabolites significantly upregulated in HCC tumors compared with non-tumor tissues, 10 were amino acids, and 7 were essential amino acids (leucine, valine, tryptophan, isoleucine, methionine, lysine, and phenylalanine). Similarly, the serum metabolomes of HCC patients before hepatectomy revealed a significant increase in 16 metabolites, including leucine, valine, and tryptophan. Our results reveal striking differences in the metabolomes of HCC tumor tissue compared with non-tumor tissue, and identify the essential amino acids leucine, valine, and tryptophan as potential metabolic biomarkers for HCC.

The combined signatures of hypoxia and cellular landscape provides a prognostic and therapeutic biomarker in hepatitis B virus-related hepatocellular carcinoma

Prognosis and treatment options of hepatitis B virus-related hepatocellular carcinoma (HBV-HCC) are generally based on tumor burden and liver function. Yet, tumor growth and therapeutic resistance of HBV-HCC are strongly influenced by intratumoral hypoxia and cells infiltrating the tumor microenvironment (TME). We, therefore, studied whether linking parameters associated with hypoxia and TME cells could have a better prediction of prognosis and therapeutic responses. Quantification of 109 hypoxia-related genes and 64 TME cells was performed in 452 HBV-HCC tumors. Prognostic hypoxia and TME cells signatures were determined based on Cox regression and meta-analysis for generating the Hypoxia-TME classifier. Thereafter, the prognosis, tumor, and immune characteristics as well as the benefit of therapies in Hypoxia-TME defined subgroups were analyzed. Patients in the Hypoxialow /TMEhigh subgroup showed a better prognosis and therapeutic responses than any other subgroups, which can be well elucidated based on the differences in terms of immune-related molecules, tumor somatic mutations, and cancer cellular signaling pathways. Notably, our analysis furthermore demonstrated the synergistic influence of hypoxia and TME on tumor metabolism and proliferation. Besides, the classifier allowed a further subdivision of patients with early- and late-HCC stages. In addition, the Hypoxia-TME classifier was validated in another independent HBV-HCC cohort (n = 144) and several pan-cancer cohorts. Overall, the Hypoxia-TME classifier showed a pretreatment predictive value for prognosis and therapeutic responses, which might provide new directions for strategizing patients with optimal therapies.

Improving the Therapeutic Efficiency of Hypoxic-Activated Prodrugs by Enhancing Hypoxia in Solid Tumors

The low sensitivity of hypoxic regions in solid tumors to radiotherapy and chemotherapy remains a major obstacle to cancer treatment. By taking advantage of hypoxic-activated prodrugs, tirapazamine (TPZ), generating cytotoxic reductive products and the glucose oxidase (GO_x)-based glucose oxidation reaction, we designed a nanodrug-loading system that combined TPZ-induced chemotherapy with GO_x-mediated cancer-orchestrated starvation therapy and cancer oxidation therapy. In this work, we first prepared mesoporous silica (MSN) loaded with TPZ. Then, in order to prevent the leakage of TPZ in advance, the surface was coated with a layer of carMOF formed by Fe³⁺ and carbenicillin (car), and GO_x was adsorbed on the outermost layer to form the final nanosystem MSN-TPZ@carMOF-GO_x (MT@c-G). GO_x could effectively consume oxygen and catalyzed glucose into gluconic acid and hydrogen peroxide. First, the generated gluconic acid lowered the pH of tumor tissues, promoted the decomposition of carMOF, and released TPZ. Second, oxygen consumption could improve the degree of hypoxia in tumor tissues, so that enhanced the activity of TPZ. Furthermore, GO_x could generate cancer-orchestrated starvation/oxidation therapy. Therefore, our study provided a new strategy that TPZ combined with GO_x achieved starvation/oxidation/chemotherapy for enhancing anticancer effects in hypoxic regions.

Activatable UCL/CT/MR-enhanced in vivo imaging-guided radiotherapy and photothermal therapy

Although sophisticated radiotherapy (RT) technology has been widely applied in clinical oncotherapy, unsatisfactory therapeutic effects due to hypoxic tumor microenvironments and complications are still prevalent. Herein, copper sulphide nanoparticles (CuS NPs) wrapped on the surface of upconversion nanoparticles (UCNPs) via manganese dioxide (MnO₂) coatings were synthesized for O₂ self-supplementing and enhanced combinational RT/photothermal therapy (PTT). In our design, the nanoplatforms can be rapidly enriched at tumor sites by the enhanced permeability and retention (EPR) effect and respond to the tumor microenvironment. The surface MnO₂ coatings can interact with over-expressed H₂O₂ in tumors and cause an abundant generation of oxygen for hypoxic improvement, leading to an enhanced RT. More importantly, by irradiation with near-infrared light, the scattered CuS NPs can convert light energy into heat to destroy tumor cells and reinforce the therapeutic effects of RT. Furthermore, these NPs also displayed excellent performances in upconversion fluorescence imaging (UCL), computerized tomographic (CT) scanning and magnetic resonance imaging (MRI), demonstrating a potential imaging-guided cancer therapy system.

Recent Strategies to Develop Innovative Photosensitizers for Enhanced Photodynamic Therapy

This review presents a robust strategy to design photosensitizers (PSs) for various species. Photodynamic therapy (PDT) is a photochemical-based treatment approach that involves the use of light combined with a light-activated chemical, referred to as a PS. Attractively, PDT is one of the alternatives to conventional cancer treatment due to its noninvasive nature, high cure rates, and low side effects. PSs play an important factor in photoinduced reactive oxygen species (ROS) generation. Although the concept of photosensitizer-based photodynamic therapy has been widely adopted for clinical trials and bioimaging, until now, to our surprise, there has been no relevant review article on rational designs of organic PSs for PDT. Furthermore, most of published review articles in PDT focused on nanomaterials and nanotechnology based on traditional PSs. Therefore, this review aimed at reporting recent strategies to develop innovative organic photosensitizers for enhanced photodynamic therapy, with each example described in detail instead of providing only a general overview, as is typically done in previous reviews of PDT, to provide intuitive, vivid, and specific insights to the readers.

Emerging strategies in developing multifunctional nanomaterials for cancer nanotheranostics

Cancer involves a collection of diseases with a common trait - dysregulation in cell proliferation. At present, traditional therapeutic strategies against cancer have limitations in tackling various tumors in clinical settings. These include chemotherapeutic resistance and the inability to overcome intrinsic physiological barriers to drug delivery. Nanomaterials have presented promising strategies for tumor treatment in recent years. Nanotheranostics combine therapeutic and bioimaging functionalities at the single nanoparticle level and have experienced tremendous growth over the past few years. This review highlights recent developments of advanced nanomaterials and nanotheranostics in three main directions: stimulus-responsive nanomaterials, nanocarriers targeting the tumor microenvironment, and emerging nanomaterials that integrate with phototherapies and immunotherapies. We also discuss the cytotoxicity and outlook of next-generation nanomaterials towards clinical implementation.

Atovaquone-HSA nano-drugs enhance the efficacy of PD-1 blockade immunotherapy by alleviating hypoxic tumor microenvironment

Background

Hypoxia is inherent character of most solid malignancies, leading to the failure of chemotherapy, radiotherapy and immunotherapy. Atovaquone, an anti-malaria drug, can alleviate tumor hypoxia by inhibiting mitochondrial complex III activity. The present study exploits atovaquone/albumin nanoparticles to improve bioavailability and tumor targeting of atovaquone, enhancing the efficacy of anti-PD-1 therapy by normalizing tumor hypoxia.

Methods

We prepared atovaquone-loaded human serum albumin (HSA) nanoparticles stabilized by intramolecular disulfide bonds, termed HSA-ATO NPs. The average size and zeta potential of HSA-ATO NPs were measured by particle size analyzer. The morphology of HSA-ATO NPs was characterized by transmission electron microscope (TEM). The bioavailability and safety of HSA-ATO NPs were assessed by animal experiments. Flow cytometry and ELISA assays were used to evaluate tumor immune microenvironment.

Results

Our data first verified that atovaquone effectively alleviated tumor hypoxia by inhibiting mitochondrial activity both in vitro and in vivo, and successfully encapsulated atovaquone in vesicle with albumin, forming HSA-ATO NPs of approximately 164 nm in diameter. We then demonstrated that the HSA-ATO NPs possessed excellent bioavailability, tumor targeting and a highly favorable biosafety profile. When combined with anti-PD-1 antibody, we observed that HSA-ATO NPs strongly enhanced the response of mice bearing tumor xenografts to immunotherapy. Mechanistically, HSA-ATO NPs promoted intratumoral CD8⁺ T cell recruitment by alleviating tumor hypoxia microenvironment, thereby enhancing the efficacy of anti-PD-1 immunotherapy.

Conclusions

Our data provide strong evidences showing that HSA-ATO NPs can serve as safe and effective nano-drugs to enhance cancer immunotherapy by alleviating hypoxic tumor microenvironment.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01034-9.

Cardiovascular toxicity of angiogenesis inhibitors and immune checkpoint inhibitors: synergistic anti-tumour effects at the cost of increased cardiovascular risk?

In the past two decades, treatment outcomes for a wide range of malignancies have improved remarkably due to the development of novel anti-cancer therapies, including vascular endothelial growth factor inhibitors (VEGFIs) and immune checkpoint inhibitors (ICIs). Despite their unprecedented anti-tumour effects, it is becoming increasingly clear that both types of agents are associated with specific cardiovascular toxicity, including hypertension, congestive heart failure, myocarditis and acceleration of atherosclerosis. Currently, VEGFI and ICI combination therapy is recommended for the treatment of advanced renal cell carcinoma (RCC) and has shown promising treatment efficacy in other tumour types as well. Consequently, VEGFI and ICI combination therapy will most likely become an important therapeutic strategy for various malignancies. However, this combinatory approach is expected to be accompanied by a substantial increase in cardiovascular risk, as both types of agents could act synergistically to induce cardiovascular sequelae. Therefore, a comprehensive baseline assessment and adequate monitoring by specialised cardio-oncology teams is essential in case these agents are used in combination, particularly in high-risk patients. This review summarises the mechanisms of action and treatment indications for currently registered VEGFIs and ICIs, and discusses their main vascular and cardiac toxicity. Subsequently, we provide the biological rationales for the observed promising synergistic anti-tumour effects of combined VEGFI/ICI administration. Lastly, we speculate on the increased risk for cardiovascular toxicity in case these agents are used in combination and its implications and future directions for the clinical situation.

Recent Advances in Asialoglycoprotein Receptor and Glycyrrhetinic Acid Receptor-Mediated and/or pH-Responsive Hepatocellular Carcinoma- Targeted Drug Delivery

BACKGROUND

Hepatocellular carcinoma (HCC) seriously affects human health, especially, it easily develops multi-drug resistance (MDR) which results in treatment failure. There is an urgent need to develop highly effective and low-toxicity therapeutic agents to treat HCC and to overcome its MDR. Targeted drug delivery systems (DDS) for cancer therapy, including nanoparticles, lipids, micelles and liposomes, have been studied for decades. Recently, more attention has been paid to multifunctional DDS containing various ligands such as polymer moieties, targeting moieties, and acid-labile linkages. The polymer moieties such as poly(ethylene glycol) (PEG), chitosan (CTS), hyaluronic acid, pullulan, poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO) protect DDS from degradation. Asialoglycoprotein receptor (ASGPR) and glycyrrhetinic acid receptor (GAR) are most often used as the targeting moieties, which are overexpressed on hepatocytes. Acid-labile linkage, catering for the pH difference between tumor cells and normal tissue, has been utilized to release drugs at tumor tissue.

OBJECTIVES

This review provides a summary of the recent progress in ASGPR and GAR-mediated and/or pH-responsive HCC-targeted drug delivery.

CONCLUSION

The multifunctional DDS may prolong systemic circulation, continuously release drugs, increase the accumulation of drugs at the targeted site, enhance the anticancer effect, and reduce side effects both in vitro and in vivo. But it is rarely used to investigate MDR of HCC; therefore, it needs to be further studied before going into clinical trials.

Serum hypoxia-inducible factor-2: A candidate prognostic biomarker for laryngeal cancer

OBJECTIVES

To determine the serum hypoxia-inducible factor-1, -2 and -3 (HIF-1, -2 and -3) levels in patients with laryngeal neoplasm, and to investigate their role in differential diagnosis, prediction of tumour characteristic and extension, and prognosis and survival.

STUDY DESIGN

Prospective, cohort study at a tertiary referral centre.

SETTINGS

The study was conducted in a tertiary medical centre.

PARTICIPANTS

Patients with benign, premalignant and malignant laryngeal neoplasms were included. Sixty-four patients with a laryngeal neoplasm were enrolled.

MAIN OUTCOME MEASURES

Serum HIF-1, -2 and -3 levels were measured from blood samples that were drawn before treatment, using ELISA.

RESULTS

A statistically significant difference between benign (HIF-1, -2, -3:4046,1 pg/mL; 2581,5 pg/mL; 1321,0 pg/mL), premalignant (HIF-1, -2, -3:3630,3 pg/mL; 3229,7 pg/mL; 2549,8 pg/mL) and malignant (HIF-1, -2, -3:3576,7 pg/mL; 2595,8 pg/mL; 1106,3 pg/mL) laryngeal neoplasms was not detected when serum HIF-1, -2 and -3 levels were compared. However, high serum HIF-2 level adversely affected survival and locoregional control and had more than 7-fold increase in hazard ratio. Moreover, serum HIF-2 was an independent prognostic factor for 2-year overall, disease-free, distant metastasis-free survival and locoregional control.

CONCLUSION

This is the first clinical study in which the diagnostic, predictive and prognostic roles of hypoxia-related biomolecules were examined in laryngeal neoplasms. Hypoxia-inducible factor-2 is a prognostic factor in larynx cancer irrespective of treatment modality.

Hypoxia increases the expression of stem cell markers in human osteosarcoma cells

Osteosarcoma (OS) is the most common primary malignant tumor of bone. It is a common phenomenon that osteosarcoma cells have a hypoxic microenvironment. Hypoxia can dedifferentiate cells of several malignant tumor types into stem cell-like phenotypes. However, the role of hypoxia in stemness induction and the expression of cancer stem cell (CSC) markers in human osteosarcoma cells has not been reported. The present study examined the effects of hypoxia on stem-like cells in the human osteosarcoma MNNG/HOS cells. Under the incubation with 1% oxygen, the expression of CSCs markers (Oct-4, Nanog and CD133) in MNNG/HOS cells were increased. Moreover, MNNG/HOS cells cultured under hypoxic conditions were more likely to proliferate into spheres and resulted in larger xenograft tumor. Hypoxia also increased the mRNA and protein levels of hypoxia-inducible factor (HIF)-1α. Then rapamycin was used, which has been shown to lower HIF-1α protein level, to inhibit the hypoxic response. Rapamycin suppressed the expression of HIF-1α protein and CSCs markers (Oct4, Nanog and CD133) in MNNG/HOS cells. In addition, pretreatment with rapamycin reduced the efficiency of MNNG/HOS cells in forming spheres and xenograft tumors. The results demonstrated that hypoxia (1% oxygen) can dedifferentiate some of the MNNG/HOS cells into stem cell-like phenotypes, and that the mTOR signaling pathway participates in this process via regulating the expression of HIF-1α protein.

Proteinaceous Hydrogels for Bioengineering Advanced 3D Tumor Models

The establishment of tumor microenvironment using biomimetic in vitro models that recapitulate key tumor hallmarks including the tumor supporting extracellular matrix (ECM) is in high demand for accelerating the discovery and preclinical validation of more effective anticancer therapeutics. To date, ECM-mimetic hydrogels have been widely explored for 3D in vitro disease modeling owing to their bioactive properties that can be further adapted to the biochemical and biophysical properties of native tumors. Gathering on this momentum, herein the current landscape of intrinsically bioactive protein and peptide hydrogels that have been employed for 3D tumor modeling are discussed. Initially, the importance of recreating such microenvironment and the main considerations for generating ECM-mimetic 3D hydrogel in vitro tumor models are showcased. A comprehensive discussion focusing protein, peptide, or hybrid ECM-mimetic platforms employed for modeling cancer cells/stroma cross-talk and for the preclinical evaluation of candidate anticancer therapies is also provided. Further development of tumor-tunable, proteinaceous or peptide 3D microtesting platforms with microenvironment-specific biophysical and biomolecular cues will contribute to better mimic the in vivo scenario, and improve the predictability of preclinical screening of generalized or personalized therapeutics.

Glucose metabolism involved in PD-L1-mediated immune escape in the malignant kidney tumour microenvironment

Programmed death receptor-ligand 1 (PD-L1) plays a crucial role in immune evasion by tumour cells. Most tumour cells exhibit energy dependency and acquire energy from glycolysis. However, the relationship between glucose metabolism and PD-L1 expression remains unclear. In this study, changes in PD-L1 expression in renal carcinoma cells were evaluated during glucose deficiency and recovery, and PD-L1 could inversely regulate glycolysis. In addition, the possible signalling pathways activated by a low level of glucose to regulate PD-L1 were tested experimentally. The results showed that glucose deficiency could upregulate PD-L1 expression in two renal cancer cell lines, 786-O and OS-RC-2. Although the native levels of PD-L1 differed in the two cell lines, the upregulated PD-L1 expression was repristinated after glucose recovery. Moreover, epidermal growth factor receptor (EGFR) expression was upregulated in both cell lines with glucose deficiency. The use of an EGFR inhibitor reversed the upregulation of PD-L1 expression induced by glucose deficiency and inhibited the phosphorylation of extracellular regulated protein kinases 1 and 2 (ERK1/2). EGFR activated by epidermal growth factor (EGF) induced PD-L1 expression and ERK1/2 phosphorylation. Furthermore, an ERK1/2 inhibitor inhibited the phosphorylation of c-Jun and decreased the elevated PD-L1 expression induced by glucose deficiency. In addition, this study also showed that 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFK-2/FBPase 3 or PFKFB3) mediated upregulation of the level of glycolysis to improve the adverse environment through PD-L1 induction. Therefore, glucose metabolism can regulate the expression of PD-L1 through the EGFR/ERK/c-Jun pathway in renal cancer, and elevated PD-L1 can also regulate glycolysis by improving the expression of PFKFB3. The findings of this study could provide a new multiple target treatment for renal cell carcinoma (RCC) therapy.

Effects of Hypoxia and Radiation-Induced Exosomes on Migration of Lung Cancer Cells and Angiogenesis of Umbilical Vein Endothelial Cells

Numerous studies have shown that exosomes play important roles in tumor biology development. However, the function of exosomal protein in cancer progression under different oxygen condition after irradiation is poorly understood. In this study, non-small cell lung cancer (NSCLC) A549 cells were γ-ray irradiated under normoxic or hypoxic conditions, then the exosomes released from the irradiated cells were collected and co-cultured with nonirradiated A549 cells or human umbilical vein endothelial cells (HUVECs). It was found that the exosomes significantly promoted the proliferation, migration and invasion of A549 cells as well as the proliferation and angiogenesis of HUVECs. Moreover, the exosomes released from hypoxic cells and/or irradiated cells had more powerful driving force in tumor progression compared to that generated from normoxia cells. Meanwhile, the proteins contained in the exosomes derived from A549 cells under different conditions were detected using tandem mass tag (TMT), and their expression profiles were analyzed. It was found that the exosome-derived protein of angiopoietin-like 4 (ANGPTL4) contributed to the migration of A549 cells as well as the angiogenesis of HUVECs, suggesting its potential as an effective diagnostic biomarker of metastasis and even a therapeutic target of lung cancer.

Advance in metabolism and target therapy in breast cancer stem cells

Breast cancer, like many other cancers, is believed to be driven by a population of cells that display stem cell properties. Recent studies suggest that cancer stem cells (CSCs) are essential for tumor progression, and tumor relapse is thought to be caused by the presence of these cells. CSC-targeted therapies have also been proposed to overcome therapeutic resistance in breast cancer after the traditional therapies. Additionally, the metabolic properties of cancer cells differ markedly from those of normal cells. The efficacy of metabolic targeted therapy has been shown to enhance anti-cancer treatment or overcome therapeutic resistance of breast cancer cells. Metabolic targeting of breast CSCs (BCSCs) may be a very effective strategy for anti-cancer treatment of breast cancer cells. Thus, in this review, we focus on discussing the studies involving metabolism and targeted therapy in BCSCs.

Therapeutic Strategies Toward Lactate Dehydrogenase Within the Tumor Microenvironment of Pancreatic Cancer

OBJECTIVES

Pancreatic stellate cells (PSCs) play a key metabolic role within the tumor microenvironment (stroma) of pancreatic ductal adenocarcinoma (PDAC), being glycolytic and associated with protumorigenic acidification from excess lactate. This study investigates the clinical significance of glycolytic enzyme lactate dehydrogenase (LDH) and determines efficacy of the novel pan-LDH inhibitor Galloflavin.

METHODS

An in vitro Transwell system was adopted for coculture of PSCs and 3 PDAC cell lines (MIA PaCa-2, PANC-1, and BxPC-3). Cells were treated with Galloflavin, and outcomes were analyzed regarding proliferation, apoptosis, lactate production, and glycolytic enzyme protein expression. Immunohistochemical staining for lactate dehydrogenase B (LDHB) was performed on 59 resected PDAC tumors annotated for clinical outcome.

RESULTS

Galloflavin reduced PDAC proliferation in monoculture (P < 0.01); however, in co-culture with PSCs, an antiproliferative effect was only evident in PANC-1 (P = 0.001). An apoptotic effect was observed in MIA PaCa-2 and BxPC-3 in coculture (P < 0.05). A reduction in media lactate was observed in coculture (P < 0.01) with PSCs. Immunohistochemistry revealed stromal and tumoral LDHB expression had no impact on survival.

CONCLUSIONS

Galloflavin has the potential to neutralize the acidic PDAC microenvironment and thereby reduce tumor invasiveness and metastasis. Patients with lower LDHB expression are more likely to be beneficial responders.

In Vivo-assembled phthalocyanine/albumin supramolecular complexes combined with a hypoxia-activated prodrug for enhanced photodynamic immunotherapy of cancer

Immunogenic photodynamic therapy (PDT) has the potential to moderate the shortfalls of cancer immunotherapy. However, its efficacy is severely limited particularly because of the lack of optimal photosensitizers and smart delivery processes and the inherent shortcomings of PDT (e.g., hypoxia resistance). Here, we demonstrate a clinically promising approach that utilizes a water-soluble phthalocyanine derivative (PcN4) concomitantly delivered with a hypoxia-activated prodrug (AQ4N) to amplify the effect of PDT and enhance cancer immunotherapy. After intravenous injection, PcN4 selectively interacted with endogenous albumin dimers and formed supramolecular complexes, providing a facile and green approach for tumor-targeted PDT. The concomitant delivery of AQ4N overcame the limitations of hypoxia in PDT and improved the antitumor activity of PDT. Treatment with PcN4-mediated and AQ4N-amplified PDT almost completely eradicated sizable primary tumors in a triple-negative breast cancer model and significantly activated CD8⁺ T cells. As the majority of tumor infiltrating CD8⁺ T cells were both PD-1- and TIM3-positive, additional combination therapy using PD-L1/PD-1 pathway blockade was warranted. After combination with immune checkpoint blockade treatment, an enhanced abscopal effect was achieved in both distant and metastatic tumors.

Role of exosomes in malignant glioma: microRNAs and proteins in pathogenesis and diagnosis

Malignant gliomas are the most common and deadly type of central nervous system tumors. Despite some advances in treatment, the mean survival time remains only about 1.25 years. Even after surgery, radiotherapy and chemotherapy, gliomas still have a poor prognosis. Exosomes are the most common type of extracellular vesicles with a size range of 30 to 100 nm, and can act as carriers of proteins, RNAs, and other bioactive molecules. Exosomes play a key role in tumorigenesis and resistance to chemotherapy or radiation. Recent evidence has shown that exosomal microRNAs (miRNAs) can be detected in the extracellular microenvironment, and can also be transferred from cell to cell via exosome secretion and uptake. Therefore, many recent studies have focused on exosomal miRNAs as important cellular regulators in various physiological and pathological conditions. A variety of exosomal miRNAs have been implicated in the initiation and progression of gliomas, by activating and/or inhibiting different signaling pathways. Exosomal miRNAs could be used as therapeutic agents to modulate different biological processes in gliomas. Exosomal miRNAs derived from mesenchymal stem cells could also be used for glioma treatment. The present review summarizes the exosomal miRNAs that have been implicated in the pathogenesis, diagnosis and treatment of gliomas. Moreover, exosomal proteins could also be involved in glioma pathogenesis. Exosomal miRNAs and proteins could also serve as non-invasive biomarkers for prognosis and disease monitoring. Video Abstract.

Cancer Stem Cells: Acquisition, Characteristics, Therapeutic Implications, Targeting Strategies and Future Prospects

Since last two decades, the major cancer research has focused on understanding the characteristic properties and mechanism of formation of Cancer stem cells (CSCs), due to their ability to initiate tumor growth, self-renewal property and multi-drug resistance. The discovery of the mechanism of acquisition of stem-like properties by carcinoma cells via epithelial-mesenchymal transition (EMT) has paved a way towards a deeper understanding of CSCs and presented a possible avenue for the development of therapeutic strategies. In spite of years of research, various challenges, such as identification of CSC subpopulation, lack of appropriate experimental models, targeting cancer cells and CSCs specifically without harming normal cells, are being faced while dealing with CSCs. Here, we discuss the biology and characteristics of CSCs, mode of acquisition of stemness (via EMT) and development of multi-drug resistance, the role of tumor niche, the process of dissemination and metastasis, therapeutic implications of CSCs and necessity of targeting them. We emphasise various strategies being developed to specifically target CSCs, including those targeting biomarkers, key pathways and microenvironment. Finally, we focus on the challenges that need to be subdued and propose the aspects that need to be addressed in future studies in order to broaden the understanding of CSCs and develop novel strategies to eradicate them in clinical applications. Graphical Abstract Cancer Stem Cells(CSCs) have gained much attention in the last few decades due to their ability to initiate tumor growth and, self-renewal property and multi-drug resistance. Here, we represent the CSC model of cancer, Characteristics of CSCs, acquisition of stemness and metastatic dissemination of cancer, Therapeutic implications of CSCs and Various strategies being employed to target and eradicate CSCs.

Silver nanoparticles: Synthesis, medical applications and biosafety

Silver nanoparticles (AgNPs) have been one of the most attractive nanomaterials in biomedicine due to their unique physicochemical properties. In this paper, we review the state-of-the-art advances of AgNPs in the synthesis methods, medical applications and biosafety of AgNPs. The synthesis methods of AgNPs include physical, chemical and biological routes. AgNPs are mainly used for antimicrobial and anticancer therapy, and also applied in the promotion of wound repair and bone healing, or as the vaccine adjuvant, anti-diabetic agent and biosensors. This review also summarizes the biological action mechanisms of AgNPs, which mainly involve the release of silver ions (Ag+), generation of reactive oxygen species (ROS), destruction of membrane structure. Despite these therapeutic benefits, their biological safety problems such as potential toxicity on cells, tissue, and organs should be paid enough attention. Besides, we briefly introduce a new type of Ag particles smaller than AgNPs, silver Ångstrom (Å, 1 Å = 0.1 nm) particles (AgÅPs), which exhibit better biological activity and lower toxicity compared with AgNPs. Finally, we conclude the current challenges and point out the future development direction of AgNPs.

Bacterial delivery of the anti-tumor azurin-like protein Laz to glioblastoma cells

Salmonella typhimurium VNP-20009 (VNP) is a non-pathogenic attenuated strain, which, as a facultative anaerobe, preferentially accumulates in hypoxic regions of solid tumors. Here, VNP was utilized as a delivery vehicle of the anti-tumor protein Lipidated azurin, Laz, which is produced by the meningitis-causing bacterium Neisseria meningitides. In brain cancer cells, Laz has been demonstrated to induce apoptosis through an interaction with the tumor suppressor protein p53. In this study, the laz gene, including its signal sequence, was cloned downstream of a hypoxia inducible promoter (HIP-1), before being electroporated into VNP. Successful ectopic expression and export of the Laz protein by VNP under hypoxic conditions were confirmed by Western blot analysis of the cell-free culture medium. Effective expression of Laz by VNP was investigated in two glioblastoma cell lines: LN-229 and U-373, with the latter line carrying a mutated version of p53; as well as in the breast cancer line MCF-7. Cytotoxicity of the VNP-Laz was assessed by determining the fluorescence of the apoptotic marker caspases 3/7. Compared to the purified Laz, VNP-Laz, significantly induced apoptosis in MCF-7, LN-229 and, to a much lower extent in U-373 cells, suggesting a p53-linked mechanism. Our results might represent a new approach of targeted gene delivery and suggest a potential application in brain tumor therapy.

Energy Metabolism in Cancer: The Roles of STAT3 and STAT5 in the Regulation of Metabolism-Related Genes

A central characteristic of many types of cancer is altered energy metabolism processes such as enhanced glucose uptake and glycolysis and decreased oxidative metabolism. The regulation of energy metabolism is an elaborate process involving regulatory proteins such as HIF (pro-metastatic protein), which reduces oxidative metabolism, and some other proteins such as tumour suppressors that promote oxidative phosphorylation. In recent years, it has been demonstrated that signal transducer and activator of transcription (STAT) proteins play a pivotal role in metabolism regulation. STAT3 and STAT5 are essential regulators of cytokine- or growth factor-induced cell survival and proliferation, as well as the crosstalk between STAT signalling and oxidative metabolism. Several reports suggest that the constitutive activation of STAT proteins promotes glycolysis through the transcriptional activation of hypoxia-inducible factors and therefore, the alteration of mitochondrial activity. It seems that STAT proteins function as an integrative centre for different growth and survival signals for energy and respiratory metabolism. This review summarises the functions of STAT3 and STAT5 in the regulation of some metabolism-related genes and the importance of oxygen in the tumour microenvironment to regulate cell metabolism, particularly in the metabolic pathways that are involved in energy production in cancer cells.

Recent advances of nanomedicines for liver cancer therapy

This review highlights recent advancements in nanomedicines for liver cancer therapy.

The Roles of CD38 and CD157 in the Solid Tumor Microenvironment and Cancer Immunotherapy

The tumor microenvironment (TME) consists of extracellular matrix proteins, immune cells, vascular cells, lymphatics and fibroblasts. Under normal physiological conditions, tissue homeostasis protects against tumor development. However, under pathological conditions, interplay between the tumor and its microenvironment can promote tumor initiation, growth and metastasis. Immune cells within the TME have an important role in the formation, growth and metastasis of tumors, and in the responsiveness of these tumors to immunotherapy. Recent breakthroughs in the field of cancer immunotherapy have further highlighted the potential of targeting TME elements, including these immune cells, to improve the efficacy of cancer prognostics and immunotherapy. CD38 and CD157 are glycoproteins that contribute to the tumorigenic properties of the TME. For example, in the hypoxic TME, the enzymatic functions of CD38 result in an immunosuppressive environment. This leads to increased immune resistance in tumor cells and allows faster growth and proliferation rates. CD157 may also aid the production of an immunosuppressive TME, and confers increased malignancy to tumor cells through the promotion of tumor invasion and metastasis. An improved understanding of CD38 and CD157 in the TME, and how these glycoproteins affect cancer progression, will be useful to develop both cancer prognosis and treatment methods. This review aims to discuss the roles of CD38 and CD157 in the TME and cancer immunotherapy of a range of solid tumor types.

Memory T cells delay the progression of atherosclerosis via AMPK signaling pathway

Background

Memory T cells play a key role in the development of atherosclerosis (AS). This study aimed to investigate the role of AMPK signaling pathway of spleen memory T cells in the pathogenesis of AS in high-fat diet (HFD) fed mice.

Methods

Mice were divided into 5 groups: normal group, AS group, AS + solvent group, AS + Compound C (AMPK inhibitor) group and AS + A-769662 (AMPK agonist) group. HFD animals were intraperitoneally treated with Compound C at 20 mg/kg thrice weekly or A-769662 at 30 mg/kg once daily for 15 weeks. Then, the degree of AS was assessed, and the proportion of memory T cell was determined by flow cytometry.

Results

AS was evident in the aorta of HFD mice. The areas of plaque formation in both AS + Compound C group and AS + A-769662 group reduced as compared to the AS group and AS + solvent group. After intervention of AMPK activity, the proportion of memory T cells in the spleen reduced as compared to the AS group and AS + solvent group; the pro proportion of memory T cells in HFD groups was markedly higher than in the normal group and this increase was more evident in the AS + Compound C than in the AS + A-769662 group.

Conclusions

The decreased memory T cells can improve AS, which may be related to the AMPK signaling pathway. Thus, AMPK in the memory T cells may serve as a target in the prevention and treatment of AS.

Hypoxia induced cancer stem cell enrichment promotes resistance to androgen deprivation therapy in prostate cancer

Androgen deprivation therapy (ADT) is the main treatment to prolong survival in advance stage prostate cancer (PCa) but associated resistance leads to the development of terminal castrate resistant PCa (CRPC). Current research demonstrates that prostate cancer stem cells (PCSC) play a critical role in the development of treatment resistance and subsequent disease progression. Despite uncertainty surrounding the origin of these cells, studies clearly show they are associated with poorer outcomes and that ADT significantly enhances their numbers. Here in we highlight how activation of HIF signalling, in response to hypoxic conditions within the tumour microenvironment, results in the expression of genes associated with stemness and EMT promoting PCSC emergence which ultimately drives tumour relapse to CRPC. Hypoxic conditions are not only enhanced by ADT but the associated decrease in AR activation also promotes PI3K/AKT signalling which actively enhances HIF and its effects on PCSC's. Furthermore, emerging evidence now indicates that HIF-2α, rather than the commonly considered HIF-1α, is the main family member that drives PCSC emergence. Taken together this clearly identifies HIF and associated pathways as key targets for new therapeutic strategies that could potentially prevent or slow PCSC promoted resistance to ADT, thus holding potential to prolong patient survival.

Hypoxia-Activated PEGylated Conditional Aptamer/Antibody for Cancer Imaging with Improved Specificity

Aptamers and antibodies, as molecular recognition probes, play critical roles in cancer diagnosis and therapy. However, their recognition ability is based on target overexpression in disease cells, not target exclusivity, which can cause on-target off-tumor effects. To address the limitation, we herein report a novel strategy to develop a conditional aptamer conjugate which recognizes its cell surface target, but only after selective activation, as determined by characteristics of the disease microenvironment, which, in our model, involve tumor hypoxia. This conditional aptamer is the result of conjugating the aptamer with PEG₅₀₀₀-azobenzene-NHS, which is responsive to hypoxia, here acting as a caging moiety of conditional recognition. More specifically, the caging moiety is unresponsive in the intact conjugate and prevents target recognition. However, in the presence of sodium dithionite or hypoxia (<0.1% O₂) or in the tumor microenvironment, the caging moiety responds by allowing conditional recognition of the cell-surface target, thereby reducing the chance of on-target off-tumor effects. It is also confirmed that the strategy can be used for developing a conditional antibody. Therefore, this study demonstrates an efficient strategy by which to develop aptamer/antibody-based diagnostic probes and therapeutic drugs for cancers with a unique hypoxic microenvironment.

Deregulated lncRNA expression profile in the mouse lung adenocarcinomas with KRAS-G12D mutation and P53 knockout

Recent studies have demonstrated that aberrant long non‐coding RNAs (lncRNAs) expression are suggested to be closely associated with multiple human diseases, lung cancer included. However, the roles of lncRNAs in lung cancer are not well understood. In this study, we used microarrays to investigate the aberrantly expressed lncRNAs in the mouse lung adenocarcinoma with P53 knockout and the Kras^G12D mutation. Results revealed that 6424 lncRNAs were differentially expressed (≥ 2‐fold change, P < .05). Two hundred and ten lncRNAs showed more than 8‐fold change and conserved across human and were further analysed in the primary mouse lung adenocarcinoma KP cells, which were isolated from the p53 knockout and the Kras^G12D mutation mice. Among all the 210 lncRNAs, 11 lncRNAs' expression was regulated by P53, 33 lncRNAs by KRAS and 13 lncRNAs by hypoxia in the primary KP cells, respectively. NONMMUT015812, which was remarkably up‐regulated in the mouse lung adenocarcinoma and negatively regulated by the P53 re‐expression, was detected to analyse its cellular function. Results showed that knockdown of NONMMUT015812 by shRNAs decreased proliferation and migration abilities of KP cells. Among those aberrantly expressed lncRNAs in the mouse lung adenocarcinoma, NONMMUT015812 was a potential oncogene.

miR-103/107 prolong Wnt/β-catenin signaling and colorectal cancer stemness by targeting Axin2

Cancer stemness drives tumor initiation, progression, metastasis, recurrence, and therapy resistance. However, mechanisms that potentiate the acquisition and maintenance of stemness fate of cancer cells remain incompletely understood. Here, we show that miR-103/107 stimulate multiple stem-like features in colorectal cancer, including expression of stem-like markers, appearance of side-population cells, and capabilities in self-renewal, tumor initiation, recurrence, and chemoresistance. Mechanistically, these stemness-promoting functions are mediated by miR-103/107-dependent repression of Axin2, a negative feedback regulator of Wnt/β-catenin signaling. Through inhibiting Axin2, miR-103/107 trigger a prolonged duration of Wnt/β-catenin signaling and a sustained induction of Wnt responsive genes. In colorectal cancer patients, miR-103/107 expression correlates inversely with Axin2 expression and a signature of miR-103/107 high and Axin2 low expression profile correlates with poor prognosis. Together, our study identifies a novel function of miR-103/107 in promoting colorectal cancer stemness by targeting Axin2 and elucidates the clinical relevance and prognostic value of this axis in colorectal cancer.

Therapeutic considerations of PARP in stem cell biology: Relevance in cancer and beyond

Cancer stem cells (CSCs) are of fundamental importance in tumor progression because of their tumor-initiating properties, their resistance to radio- and chemotherapy, their invasive properties and their propensity to escape immune responses that together contribute to tumor relapse. These highly aggressive features underscore the importance of constantly identifying new and innovative therapeutic solutions to eradicate these cells. In this narrative review we discuss recent findings on the involvement of PARP family members in cancer stem cell biology and the benefit of their inhibition. Nonetheless, an important limitation in the use of PARP inhibitors is the emergence of a prominent function of PARP1 in non-cancer stem cell biology including stem cell maintenance and differentiation during development, neurogenesis or adipogenesis. Thus, we also summarize the dominant discoveries revealing the importance of PARP1 in normal stem cell biology.

Cancer targeting peptides

Despite continuing advances in the development of biomacromolecules for therapeutic purposes, successful application of these often large and hydrophilic molecules has been hindered by their inability to efficiently traverse the cellular plasma membrane. In recent years, cell-penetrating peptides (CPPs) have received considerable attention as a promising class of delivery vectors due to their ability to mediate the efficient import of a large number of cargoes in vitro and in vivo. However, the lack of target specificity of CPPs remains a major obstacle to their clinical development. To address this issue, researchers have developed strategies in which chemotherapeutic drugs are conjugated to cancer targeting peptides (CTPs) that exploit the unique characteristics of the tumor microenvironment or cancer cells, thereby improving cancer cell specificity. This review highlights several of these strategies that are currently in use, and discusses how multi-component nanoparticles conjugated to CTPs can be designed to provide a more efficient cancer therapeutic delivery strategy.

A Cellular Taxonomy of the Bone Marrow Stroma in Homeostasis and Leukemia

Stroma is a poorly defined non-parenchymal component of virtually every organ with key roles in organ development, homeostasis, and repair. Studies of the bone marrow stroma have defined individual populations in the stem cell niche regulating hematopoietic regeneration and capable of initiating leukemia. Here, we use single-cell RNA sequencing (scRNA-seq) to define a cellular taxonomy of the mouse bone marrow stroma and its perturbation by malignancy. We identified seventeen stromal subsets expressing distinct hematopoietic regulatory genes spanning new fibroblastic and osteoblastic subpopulations including distinct osteoblast differentiation trajectories. Emerging acute myeloid leukemia impaired mesenchymal osteogenic differentiation and reduced regulatory molecules necessary for normal hematopoiesis. These data suggest that tissue stroma responds to malignant cells by disadvantaging normal parenchymal cells. Our taxonomy of the stromal compartment provides a comprehensive bone marrow cell census and experimental support for cancer cell crosstalk with specific stromal elements to impair normal tissue function and thereby enable emergent cancer.