Phosphatidylserine is a marker of tumor vasculature and a potential target for cancer imaging and therapy

Exposed Phosphatidylserine as a Biomarker for Clear Identification of Breast Cancer Brain Metastases in Mouse Models

Brain metastasis is the most common intracranial malignancy in adults. The prognosis is extremely poor, partly because most patients have more than one brain lesion, and the currently available therapies are nonspecific or inaccessible to those occult metastases due to an impermeable blood-tumor barrier (BTB). Phosphatidylserine (PS) is externalized on the surface of viable endothelial cells (ECs) in tumor blood vessels. In this study, we have applied a PS-targeting antibody to assess brain metastases in mouse models. Fluorescence microscopic imaging revealed that extensive PS exposure was found exclusively on vascular ECs of brain metastases. The highly sensitive and specific binding of the PS antibody enables individual metastases, even micrometastases containing an intact BTB, to be clearly delineated. Furthermore, the conjugation of the PS antibody with a fluorescence dye, IRDye 800CW, or a radioisotope, 125I, allowed the clear visualization of individual brain metastases by optical imaging and autoradiography, respectively. In conclusion, we demonstrated a novel strategy for targeting brain metastases based on our finding that abundant PS exposure occurs on blood vessels of brain metastases but not on normal brain, which may be useful for the development of imaging and targeted therapeutics for brain metastases.

Lipid metabolism associated crosstalk: the bidirectional interaction between cancer cells and immune/stromal cells within the tumor microenvironment for prognostic insight

Cancer is closely related to lipid metabolism, with the tumor microenvironment (TME) containing numerous lipid metabolic interactions. Cancer cells can bidirectionally interact with immune and stromal cells, the major components of the TME. This interaction is primarily mediated by fatty acids (FAs), cholesterol, and phospholipids. These interactions can lead to various physiological changes, including immune suppression, cancer cell proliferation, dissemination, and anti-apoptotic effects on cancer cells. The physiological modulation resulting from this lipid metabolism-associated crosstalk between cancer cells and immune/stromal cells provides valuable insights into cancer prognosis. A comprehensive literature review was conducted to examine the function of the bidirectional lipid metabolism interactions between cancer cells and immune/stromal cells within the TME, particularly how these interactions influence cancer prognosis. A novel autophagy-extracellular vesicle (EV) pathway has been proposed as a mediator of lipid metabolism interactions between cancer cells and immune cells/stromal cells, impacting cancer prognosis. As a result, different forms of lipid metabolism interactions have been described as being linked to cancer prognosis, including those mediated by the autophagy-EV pathway. In conclusion, understanding the bidirectional lipid metabolism interactions between cancer cells and stromal/immune cells in the TME can help develop more advanced prognostic approaches for cancer patients.

Investigation of miltefosine-model membranes interactions at the molecular level for two different PS levels modeling cancer cells

Miltefosine (MLT) is a broad-spectrum drug included in the alkylphospholipids (APL) used against leishmania and various types of cancer. The most crucial feature of APLs is that they are thought to only kill cancerous cells without harming normal cells. However, the molecular mechanism of action of APLs is not completely understood. The increase in the phosphatidylserine (PS) ratio is a marker showing the stage of cancer and even metastasis. The goal of this research was to investigate the molecular effects of miltefosine at the molecular level in different PS ratios. The effects of MLT on membrane phase transition, membrane orders, and dynamics were studied using DPPC/DPPS (3:1) and DPPC/DPPS (1:1) multilayer (MLV) vesicles mimicking DPPS ratio variation, Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared spectroscopy (FTIR). Our findings indicate that miltefosine is evidence at the molecular level that it is directed towards the tumor cell and that the drug's effect increases with the increase of anionic lipids in the membrane depending on the stage of cancer.

Immunogenic Treatment of Metastatic Breast Cancer Using Targeted Carbon Nanotube Mediated Photothermal Therapy in Combination with Anti-Programmed Cell Death Protein-1

The high prevalence of breast cancer is a global health concern, compounded by the lack of safe or effective treatments for its advanced stages. These facts urge the development of novel treatment strategies. Annexin A5 (ANXA5) is a natural human protein that binds with high specificity to phosphatidylserine, a phospholipid tightly maintained in the inner leaflet of the cell membrane on most healthy cells but externalized in tumor cells and the tumor vasculature. Here, we have developed a targeted photosensitizer for photothermal therapy (PTT) of solid tumors through the functionalization of single-walled carbon nanotubes (SWCNTs) to ANXA5-the SWCNT-ANXA5 conjugate. The ablation of tumors through the SWCNT-ANXA5-mediated PTT synergizes with checkpoint inhibition, creating a systemic anticancer immune response. In vitro ablation of cells incubated with the conjugate promoted cell death in a dose-dependent and targeted manner. This treatment strategy was tested in vivo with the orthotopic EMT6 breast tumor model in female balb/cJ mice. Enhanced therapeutic effects were achieved by using intratumoral injection of the conjugate and treating tumors at a lower PTT temperature (45°C). Intratumoral injection prevented the accumulation of the SWCNTs in major clearance organs. When combined with checkpoint inhibition of anti-programmed cell death protein-1, SWCNT-ANXA5-mediated PTT increased survival and 80% of the mice survived for 100 days. Evidence of immune system activation by flow cytometry of splenic cells strengthens the hypothesis of an abscopal effect as a mechanism of prolonged survival. SIGNIFICANCE STATEMENT: This study demonstrated a relatively high survival rate (80% at 100 days) of mice with aggressive breast cancer when treated with photothermal therapy using the SWCNT-ANXA5 conjugate injected intratumorally and combined with immune stimulation using the anti-programmed cell death protein-1 checkpoint inhibitor. Photothermal therapy was accomplished by maintaining the tumor temperature at a relatively low level of 45°C and avoiding accumulation of the nanotubes in the clearance organs by using intratumoral administration.

Myricanol improves metabolic profiles in dexamethasone induced lipid and protein metabolism disorders in mice

Myricanol (MY) is one of the main active components from bark of Myrica Rubra. It is demonstrated that MY rescues dexamethasone (DEX)-induced muscle dysfunction via activating silent information regulator 1 (SIRT1) and increasing adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation. Since SIRT1 and AMPK are widely involved in the metabolism of nutrients, we speculated that MY may exert beneficial effects on DEX-induced metabolic disorders. This study for the first time applied widely targeted metabolomics to investigate the beneficial effects of MY on glucose, lipids, and protein metabolism in DEX-induced metabolic abnormality in mice. The results showed that MY significantly reversed DEX-induced soleus and gastrocnemius muscle weight loss, muscle fiber damage, and muscle strength loss. MY alleviated DEX-induced metabolic disorders by increasing SIRT1 and glucose transporter type 4 (GLUT4) expressions. Additionally, myricanol prevented muscle cell apoptosis and atrophy by inhibiting caspase 3 cleavages and muscle ring-finger protein-1 (MuRF1) expression. Metabolomics showed that MY treatment reversed the serum content of carnitine ph-C1, palmitoleic acid, PS (16:0_17:0), PC (14:0_20:5), PE (P-18:1_16:1), Cer (t18:2/38:1(2OH)), four amino acids and their metabolites, and 16 glycerolipids in DEX mice. Kyoto encyclopedia of genes and genomes (KEGG) and metabolic set enrichment analysis (MSEA) analysis revealed that MY mainly affected metabolic pathways, glycerolipid metabolism, lipolysis, fat digestion and absorption, lipid and atherosclerosis, and cholesterol metabolism pathways through regulation of metabolites involved in glutathione, butanoate, vitamin B6, glycine, serine and threonine, arachidonic acid, and riboflavin metabolism. Collectively, MY can be used as an attractive therapeutic agent for DEX-induced metabolic abnormalities.

Graph-Based Analyses of Dynamic Water-Mediated Hydrogen-Bond Networks in Phosphatidylserine: Cholesterol Membranes

Phosphatidylserine lipids are anionic molecules present in eukaryotic plasma membranes, where they have essential physiological roles. The altered distribution of phosphatidylserine in cells such as apoptotic cancer cells, which, unlike healthy cells, expose phosphatidylserine, is of direct interest for the development of biomarkers. We present here applications of a recently implemented Depth-First-Search graph algorithm to dissect the dynamics of transient water-mediated lipid clusters at the interface of a model bilayer composed of 1-palmytoyl-2-oleoyl-sn-glycero-2-phosphatidylserine (POPS) and cholesterol. Relative to a reference POPS bilayer without cholesterol, in the POPS:cholesterol bilayer there is a somewhat less frequent sampling of relatively complex and extended water-mediated hydrogen-bond networks of POPS headgroups. The analysis protocol used here is more generally applicable to other lipid:cholesterol bilayers.

Chimeric TIM-4 receptor-modified T cells targeting phosphatidylserine mediates both cytotoxic anti-tumor responses and phagocytic uptake of tumor-associated antigen for T cell cross-presentation

To leverage complementary mechanisms for cancer cell removal, we developed a novel cell engineering and therapeutic strategy co-opting phagocytic clearance and antigen presentation activity into T cells. We engineered a chimeric engulfment receptor (CER)-1236, which combines the extracellular domain of TIM-4, a phagocytic receptor recognizing the "eat me" signal phosphatidylserine, with intracellular signaling domains (TLR2/TIR, CD28, and CD3ζ) to enhance both TIM-4-mediated phagocytosis and T cell cytotoxic function. CER-1236 T cells demonstrate target-dependent phagocytic function and induce transcriptional signatures of key regulators responsible for phagocytic recognition and uptake, along with cytotoxic mediators. Pre-clinical models of mantle cell lymphoma (MCL) and EGFR mutation-positive non-small cell lung cancer (NSCLC) demonstrate collaborative innate-adaptive anti-tumor immune responses both in vitro and in vivo. Treatment with BTK (MCL) and EGFR (NSCLC) inhibitors increased target ligand, conditionally driving CER-1236 function to augment anti-tumor responses. We also show that activated CER-1236 T cells exhibit superior cross-presentation ability compared with conventional T cells, triggering E7-specific TCR T responses in an HLA class I- and TLR-2-dependent manner, thereby overcoming the limited antigen presentation capacity of conventional T cells. Therefore, CER-1236 T cells have the potential to achieve tumor control by eliciting both direct cytotoxic effects and indirect-mediated cross-priming.

Native Planar Asymmetric Suspended Membrane for Single-Molecule Investigations: Plasma Membrane on a Chip

Cellular plasma membranes, in their role as gatekeepers to the external environment, host numerous protein assemblies and lipid domains that manage the movement of molecules into and out of cells, regulate electric potential, and direct cell signaling. The ability to investigate these roles on the bilayer at a single-molecule level in a controlled, in vitro environment while preserving lipid and protein architectures will provide deeper insights into how the plasma membrane works. A tunable silicon microarray platform that supports stable, planar, and asymmetric suspended lipid membranes (SLIM) using synthetic and native plasma membrane vesicles for single-molecule fluorescence investigations is developed. Essentially, a "plasma membrane-on-a-chip" system that preserves lipid asymmetry and protein orientation is created. By harnessing the combined potential of this platform with total internal reflection fluorescence (TIRF) microscopy, the authors are able to visualize protein complexes with single-molecule precision. This technology has widespread applications in biological processes that happen at the cellular membranes and will further the knowledge of lipid and protein assemblies.

Pathobiological functions and clinical implications of annexin dysregulation in human cancers

Annexins are an extensive superfamily of structurally related calcium- and phospholipid-binding proteins, largely conserved and widely distributed among species. Twelve human annexins have been identified, referred to as Annexin A1-13 (A12 remains as of yet unassigned), whose genes are spread throughout the genome on eight different chromosomes. According to their distinct tissue distribution and subcellular localization, annexins have been functionally implicated in a variety of biological processes relevant to both physiological and pathological conditions. Dysregulation of annexin expression patterns and functions has been revealed as a common feature in multiple cancers, thereby emerging as potential biomarkers and molecular targets for clinical application. Nevertheless, translation of this knowledge to the clinic requires in-depth functional and mechanistic characterization of dysregulated annexins for each individual cancer type, since each protein exhibits varying expression levels and phenotypic specificity depending on the tumor types. This review specifically and thoroughly examines the current knowledge on annexin dysfunctions in carcinogenesis. Hence, available data on expression levels, mechanism of action and pathophysiological effects of Annexin A1-13 among different cancers will be dissected, also further discussing future perspectives for potential applications as biomarkers for early diagnosis, prognosis and molecular-targeted therapies. Special attention is devoted to head and neck cancers (HNC), a complex and heterogeneous group of aggressive malignancies, often lately diagnosed, with high mortality, and scarce therapeutic options.

Externalization of Mitochondrial PDCE2 on Irradiated Endothelium as a Target for Radiation-Guided Drug Delivery and Precision Thrombosis of Pathological Vasculature

Endothelial cells are highly sensitive to ionizing radiation, and exposure leads to multiple adaptive changes. Remarkably, part of this response is the translocation of normally intracellular proteins to the cell surface. It is unclear whether this ectopic expression has a protective or deleterious function, but, regardless, these surface-exposed proteins may provide unique discriminatory targets for radiation-guided drug delivery to vascular malformations or tumor vasculature. We investigated the ability of an antibody–thrombin conjugate targeting mitochondrial PDCE2 (E2 subunit of pyruvate dehydrogenase) to induce precision thrombosis on irradiated endothelial cells in a parallel-plate flow system. Click-chemistry was used to create antibody–thrombin conjugates targeting PDCE2 as the vascular targeting agent (VTA). VTAs were injected into the parallel-plate flow system with whole human blood circulating over irradiated cells. The efficacy and specificity of fibrin-thrombus formation was assessed relative to non-irradiated controls. The PDCE2-targeting VTA dose-dependently increased thrombus formation: minimal thrombosis was induced in response to 5 Gy radiation; doses of 15 and 25 Gy induced significant thrombosis with equivalent efficacy. Negligible VTA binding or thrombosis was demonstrated in the absence of radiation or with non-targeted thrombin. PDCE2 represents a unique discriminatory target for radiation-guided drug delivery and precision thrombosis in pathological vasculature.

Mesenchymal Stem Cell-Derived Antimicrobial Peptides as Potential Anti-Neoplastic Agents: New Insight into Anticancer Mechanisms of Stem Cells and Exosomes

Mesenchymal stem cells (MSCs), as adult multipotent cells, possess considerable regenerative and anti-neoplastic effects, from inducing apoptosis in the cancer cells to reducing multidrug resistance that bring them up as an appropriate alternative for cancer treatment. These cells can alter the behavior of cancer cells, the condition of the tumor microenvironment, and the activity of immune cells that result in tumor regression. It has been observed that during inflammatory conditions, a well-known feature of the tumor microenvironment, the MSCs produce and release some molecules called “antimicrobial peptides (AMPs)” with demonstrated anti-neoplastic effects. These peptides have remarkable targeted anticancer effects by attaching to the negatively charged membrane of neoplastic cells, disrupting the membrane, and interfering with intracellular pathways. Therefore, AMPs could be considered as a part of the wide-ranging anti-neoplastic effects of MSCs. This review focuses on the possible anti-neoplastic effects of MSCs-derived AMPs and their mechanisms. It also discusses preconditioning approaches and using exosomes to enhance AMP production and delivery from MSCs to cancer cells. Besides, the clinical administration of MSCs-derived AMPs, along with their challenges in clinical practice, were debated.

Algorithm to catalogue topologies of dynamic lipid hydrogen-bond networks

Lipid membrane interfaces host reactions essential for the functioning of cells. The hydrogen-bonding environment at the membrane interface is particularly important for binding of proteins, drug molecules, and ions. We present here the implementation and applications of a depth-first search algorithm that analyzes dynamic lipid interaction networks. Lipid hydrogen-bond networks sampled transiently during simulations of lipid bilayers are clustered according to main types of topologies that characterize three-dimensional arrangements of lipids connected to each other via short water bridges. We characterize the dynamics of hydrogen-bonded lipid clusters in simulations of model POPE and POPE:POPG membranes that are often used for bacterial membrane proteins, in a model of the Escherichia coli membrane with six different lipid types, and in POPS membranes. We find that all lipids sample dynamic hydrogen-bonded networks with linear, star, or circular arrangements of the lipid headgroups, and larger networks with combinations of these three types of topologies. Overall, linear lipid-water bridges tend to be short. Water-mediated lipid clusters in all membranes with PE lipids tend to be somewhat small, with about four lipids in all membranes studied here. POPS membranes allow circular arrangements of three POPS lipids to be sampled frequently, and complex arrangements of linear, star, and circular paths may also be sampled. These findings suggest a molecular picture of the membrane interface whereby lipid molecules transiently connect in clusters with somewhat small spatial extension.

The role of microvesicles as biomarkers in the screening of colorectal neoplasm

Background

Colorectal cancer (CRC) is the second cause of cancer death worldwide. The role of circulating microvesicles as a screening tool is a novel, yet effective approach that warrants prioritised research.

Methods

In a two‐gate diagnostic accuracy study, 35 patients with benign colorectal polyps (BCRP) (n = 16) and colorectal cancer (CRC) (n = 19) were compared to 17 age‐matched healthy controls. Total annexin‐V positive microvesicles and sub‐populations positive for selected biomarkers relevant to bowel neoplasm were evaluated in patients' plasma using flow cytometry. Statistical methods including factor analysis utilising two component factors were performed to obtain optimal diagnostic accuracy of microvesicles in identifying patients with colorectal neoplasms.

Results

Total plasma microvesicles, and sub‐populations positive for CD31, CD42a, CD31+/CD42a‐, EPHB2, ICAM and LGR5 (component factor‐1) were able to identify patients with BCRP and CRC with a receiver operator curve (AUC) accuracy of a 100% (95% CI: 100%–100%) and 95% (95% CI: 88%–100%), respectively. To identify patients with BCRP, a cut‐off point value of component factor‐1761 microvesicles/μl demonstrated a 100% sensitivity, specificity and negative predictive value (NPV) and a 93% positive predictive value (PPV). To identify patients with CRC, a cut‐off value of component factor‐1 ³439 microvesicles/μl demonstrated a 100% sensitivity, specificity and NPV and a 65% PPV. CEA+ microvesicles sub‐population were significantly (p < 0.02) higher in CRC in comparison to BCRP.

Conclusions

Microvesicles as biomarkers for the early and accurate detection of CRC is a simple and effective tool that yields a potential breakthrough in clinical management.

Clinical Applications and Anticancer Effects of Antimicrobial Peptides: From Bench to Bedside

Cancer is a multifaceted global health issue and one of the leading causes of death worldwide. In recent years, medical science has achieved great advances in the diagnosis and treatment of cancer. Despite the numerous advantages of conventional cancer therapies, there are major drawbacks including severe side effects, toxicities, and drug resistance. Therefore, the urgency of developing new drugs with low cytotoxicity and treatment resistance is increasing. Antimicrobial peptides (AMPs) have attracted attention as a novel therapeutic strategy for the treatment of various cancers, targeting tumor cells with less toxicity to normal tissues. In this review, we present the structure, biological function, and underlying mechanisms of AMPs. The recent experimental studies and clinical trials on anticancer peptides in different cancer types as well as the challenges of their clinical application have also been discussed.

Future Prospects of Immunotherapy in Non-Small-Cell Lung Cancer Patients: Is There Hope in Other Immune Checkpoints Targeting Molecules?

Currently, one of the leading treatments for non-small-cell lung cancer is immunotherapy involving immune checkpoint inhibitors. These monoclonal antibodies restore the anti-tumour immune response altered by negative immune checkpoint interactions. The most commonly used immunotherapeutics in monotherapy are anti-PD-1 and anti-PD-L1 antibodies. The effectiveness of both groups of antibodies has been proven in many clinical trials, which have translated into positive immunotherapeutic registrations for cancer patients worldwide. These antibodies are generally well tolerated, and certain patients achieve durable responses. However, given the resistance of some patients to this form of therapy, along with its other drawbacks, such as adverse events, alternatives are constantly being sought. Specifically, new drugs targeting already known molecules are being tested, and new potential targets are being explored. The aim of this paper is to provide an overview of the latest developments in this area.

Multi-Omics Prognostic Signatures Based on Lipid Metabolism for Colorectal Cancer

Background: The potential biological processes and laws of the biological components in malignant tumors can be understood more systematically and comprehensively through multi-omics analysis. This study elaborately explored the role of lipid metabolism in the prognosis of colorectal cancer (CRC) from the metabonomics and transcriptomics.

Methods: We performed K-means unsupervised clustering algorithm and t test to identify the differential lipid metabolites determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) in the serum of 236 CRC patients of the First Hospital of Jilin University (JLUFH). Cox regression analysis was used to identify prognosis-associated lipid metabolites and to construct multi-lipid-metabolite prognostic signature. The composite nomogram composed of independent prognostic factors was utilized to individually predict the outcome of CRC patients. Glycerophospholipid metabolism was the most significant enrichment pathway for lipid metabolites in CRC, whose related hub genes (GMRHGs) were distinguished by gene set variation analysis (GSVA) and weighted gene co-expression network analysis (WGCNA). Cox regression and least absolute shrinkage and selection operator (LASSO) regression analysis were utilized to develop the prognostic signature.

Results: Six-lipid-metabolite and five-GMRHG prognostic signatures were developed, indicating favorable survival stratification effects on CRC patients. Using the independent prognostic factors as variables, we established a composite nomogram to individually evaluate the prognosis of CRC patients. The AUCs of one-, three-, and five-year ROC curves were 0.815, 0.815, and 0.805, respectively, showing auspicious prognostic accuracy. Furthermore, we explored the potential relationship between tumor microenvironment (TME) and immune infiltration. Moreover, the mutational frequency of TP53 in the high-risk group was significantly higher than that in the low-risk group (p < 0.001), while in the coordinate mutational status of TP53, the overall survival of CRC patients in the high-risk group was significantly lower than that in low-risk group with statistical differences.

Conclusion: We identified the significance of lipid metabolism for the prognosis of CRC from the aspects of metabonomics and transcriptomics, which can provide a novel perspective for promoting individualized treatment and revealing the potential molecular biological characteristics of CRC. The composite nomogram including a six-lipid-metabolite prognostic signature is a promising predictor of the prognosis of CRC patients.

LvHemB1, a novel cationic antimicrobial peptide derived from the hemocyanin of Litopenaeus vannamei, induces cancer cell death by targeting mitochondrial voltage-dependent anion channel 1

Current cancer treatment regimens such as chemotherapy and traditional chemical drugs have adverse side effects including the appearance of drug-resistant tumor cells. For these reasons, it is imperative to find novel therapeutic agents that overcome these factors. To this end, we explored a cationic antimicrobial peptide derived from Litopenaeus vannamei hemocyanin (designated LvHemB1) that induces cancer cell death, but sparing normal cells. LvHemB1 inhibits the proliferation of human cervical (HeLa), esophageal (EC109), hepatocellular (HepG2), and bladder (EJ) cancer cell lines, but had no significant effect on normal liver cell lines (T-antigen-immortalized human liver epithelial (THLE-3) cells). In addition to its antiproliferative effects, LvHemB1 induced apoptosis, by permeating cells and targeting mitochondrial voltage-dependent anion channel 1 (VDAC1). Colocalization studies revealed the localization of LvHemB1 in mitochondria, while molecular docking and pull-down analyses confirmed LvHemB1-VDAC1 interaction. Moreover, LvHemB1 causes loss in mitochondrial membrane potential and increases levels of reactive oxygen species (ROS) and apoptotic proteins (caspase-9, caspase-3, and Bax (Bcl-2-associated X)), which results in mitochondrial-mediated apoptosis. Thus, peptide LvHemB1 has the potential of being used as an anticancer agent due to its antiproliferation effect and targeting to VDAC1 to cause mitochondrial dysfunction in cancer cells, as well as its ability to induce apoptosis by increasing ROS levels, and the expression of proapoptotic proteins.

The Apoptosis Paradox in Cancer

Cancer growth represents a dysregulated imbalance between cell gain and cell loss, where the rate of proliferating mutant tumour cells exceeds the rate of those that die. Apoptosis, the most renowned form of programmed cell death, operates as a key physiological mechanism that limits cell population expansion, either to maintain tissue homeostasis or to remove potentially harmful cells, such as those that have sustained DNA damage. Paradoxically, high-grade cancers are generally associated with high constitutive levels of apoptosis. In cancer, cell-autonomous apoptosis constitutes a common tumour suppressor mechanism, a property which is exploited in cancer therapy. By contrast, limited apoptosis in the tumour-cell population also has the potential to promote cell survival and resistance to therapy by conditioning the tumour microenvironment (TME)-including phagocytes and viable tumour cells-and engendering pro-oncogenic effects. Notably, the constitutive apoptosis-mediated activation of cells of the innate immune system can help orchestrate a pro-oncogenic TME and may also effect evasion of cancer treatment. Here, we present an overview of the implications of cell death programmes in tumour biology, with particular focus on apoptosis as a process with "double-edged" consequences: on the one hand, being tumour suppressive through deletion of malignant or pre-malignant cells, while, on the other, being tumour progressive through stimulation of reparatory and regenerative responses in the TME.

The role of phosphatidylserine on the membrane in immunity and blood coagulation

The negatively charged aminophospholipid, phosphatidylserine (PtdSer), is located in the inner leaflet of the plasma membrane in normal cells, and may be exposed to the outer leaflet under some immune and blood coagulation processes. Meanwhile, Ptdser exposed to apoptotic cells can be recognized and eliminated by various immune cells, whereas on the surface of activated platelets Ptdser interacts with coagulation factors prompting enhanced production of thrombin which significantly facilitates blood coagulation. In the case where PtdSer fails in exposure or mistakenly occurs, there are occurrences of certain immunological and haematological diseases, such as the Scott syndrome and Systemic lupus erythematosus. Besides, viruses (e.g., Human Immunodeficiency Virus (HIV), Ebola virus (EBOV)) can invade host cells through binding the exposed PtdSer. Most recently, the Corona Virus Disease 2019 (COVID-19) has been similarly linked to PtdSer or its receptors. Therefore, it is essential to comprehensively understand PtdSer and its functional characteristics. Therefore, this review summarizes Ptdser, its eversion mechanism; interaction mechanism, particularly with its immune receptors and coagulation factors; recognition sites; and its function in immune and blood processes. This review illustrates the potential aspects for the underlying pathogenic mechanism of PtdSer-related diseases, and the discovery of new therapeutic strategies as well.

Phosphatidylserine Exposed Lipid Bilayer Models for Understanding Cancer Cell Selectivity of Natural Compounds: A Molecular Dynamics Simulation Study

Development of drugs that are selectively toxic to cancer cells and safe to normal cells is crucial in cancer treatment. Evaluation of membrane permeability is a key metric for successful drug development. In this study, we have used in silico molecular models of lipid bilayers to explore the effect of phosphatidylserine (PS) exposure in cancer cells on membrane permeation of natural compounds Withaferin A (Wi-A), Withanone (Wi-N), Caffeic Acid Phenethyl Ester (CAPE) and Artepillin C (ARC). Molecular dynamics simulations were performed to compute permeability coefficients. The results indicated that the exposure of PS in cancer cell membranes facilitated the permeation of Wi-A, Wi-N and CAPE through a cancer cell membrane when compared to a normal cell membrane. In the case of ARC, PS exposure did not have a notable influence on its permeability coefficient. The presented data demonstrated the potential of PS exposure-based models for studying cancer cell selectivity of drugs.

Mertk: An emerging target in cancer biology and immuno-oncology

Mertk, a type I Receptor Tyrosine Kinase (RTK) and member of the TAM (Tyro3, Axl, and Mertk) family of homologous tyrosine kinases, has important roles in signal transduction both homeostatically on normal cells as well as patho-physiologically on both tumor-associated macrophages and malignant cells by its overexpression in a wide array of cancers. The main ligands of Mertk are Vitamin K-modified endogenous proteins Gas6 and Protein S (ProS1), heterobifunctional modular proteins that bind Mertk via two carboxyl-terminal laminin-like globular (LG) domains, and an N-terminal Gla domain that binds anionic phospholipids, whereby externalized phosphatidylserine (PS) on stressed viable and caspase-activated apoptotic cells is most emblematic. Recent studies indicate that Vitamin K-dependent γ-carboxylation on the N-terminal Gla domain of Gas6 and Protein S is necessary for PS binding and Mertk activation, implying that Mertk is preferentially active in tissues where there is high externalized PS, such as the tumor microenvironment (TME) and acute virally infected tissues. Once stimulated, activated Mertk can provide a survival advantage for cancer cells as well as drive compensatory proliferation. On monocytes and tumor-associated macrophages, Mertk promotes efferocytosis and acts as an inhibitory receptor that impairs host anti-tumor immunity, functioning akin to a myeloid checkpoint inhibitor. In recent years, inhibition of Mertk has been implicated in a dual role to enhance the sensitivity of cancer cells to cytotoxic agents along with improving host anti-tumor immunity with anti-PD-1/PD-L1 immunotherapy. Here, we examine the rationale of Mertk-targeted immunotherapies, the current and potential therapeutic strategies, the clinical status of Mertk-specific therapies, and potential challenges and obstacles for Mertk-focused therapies.

Real-time monitoring of active caspase 3 during AFB1 induced apoptosis based on SERS-fluorescent dual mode signals

Aflatoxin B1 (AFB1) is the most toxic mycotoxin. Usually, the toxin activated apoptosis is considered mostly through intrinsic mitochondrial pathway while the caspase family as promoter and executor plays a crucial role. In this paper, a real-time and in situ detection of caspase 3 in living cells based on SERS-fluorescence dual mode nanosensor was studied. Firstly, gold nanotriangles (AuNTs) modified with the caspase 3 specifically recognized polypeptide chain DEVD were synthesized as both SERS enhanced substrate and fluorescent quencher. Rhodamine B (Rb) as both Raman and fluorescent signal molecules was modified on the N end of DEVD chain. After active caspase 3 specifically cut off the recognition site in DEVD, partial peptide chain with Rb fell off from the surface of AuNTs. Thus, the Raman signal of Rb decreased while its fluorescent signal recovered. There was a good linear relationship between caspase 3 and both the SERS and fluorescence signals of Rb. The minimum detection limit was 0.001 nM. After cells were stimulated by AFB1, when Cyt C in the cytoplasm reached a certain level, caspase 3 was activated. This nanosensor was realized in certain living cells (HepG2, HeLa and A549). Based on monitoring the activation of specific apoptotic markers, the conduction of marker signals in real time can provide more detailed information for apoptosis.

Membrane model as key tool in the study of glutathione-s-transferase mediated anticancer drug resistance

Glutathione-s-transferase is believed to be involved in the resistance to chemotherapeutic drugs, which depends on the interaction with the cell membranes. In this study, we employed Langmuir monolayers of a mixture of phospholipids and cholesterol (MIX) as models for tumor cell membranes and investigated their interaction with the anticancer drugs cisplatin (CDDP) and doxorubicin (DOX). We found that both DOX and CDDP expand and affect the elasticity of MIX monolayers, but these effects are hindered when glutathione-s-transferase (GST) and its cofactor glutathione (GSH) are incorporated. Changes are induced by DOX or CDDP on the polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) data for MIX/GST/GSH monolayers, thus denoting some degree of interaction that is not sufficient to alter the monolayer mechanical properties. Overall, the results presented here give support to the hypothesis of the inactivation of DOX and CDDP by GST and point to possible directions to detect and fight drug resistance.

Delivery of IL-2 to the T Cell Surface Through Phosphatidylserine Permits Robust Expansion of CD8 T Cells

The phospholipid phosphatidylserine (PS) is naturally maintained on the cytoplasmic side of the plasma membrane. Independent of apoptosis, PS is redistributed to the surface of CD8 T cells in response to TCR-mediated activation. Annexin V (AnnV) is a protein known to bind PS with high affinity and has been effectively utilized to anchor antigen to the surface of CD8 T cells. To expand these studies, we aimed to exploit TCR activation driven PS exposure as a target to deliver cytokine, namely interleukin-2 (IL-2), to the surface of CD8 T cells. This was accomplished using a novel chimeric fusion protein of annexin V and interleukin 2 (AnnV-IL2). In vitro analysis revealed that AnnV-IL2 is able to specifically bind PS on the T cell surface following TCR stimulation. Consequently, AnnV-IL2 proved to be significantly more effective at enhancing T cell activation compared to recombinant IL-2. In vivo, AnnV-IL2 promotes robust expansion of antigen-specific cells capable of interferon gamma (IFNγ) production when administered following peptide vaccination. Importantly, upon antigen rechallenge, AnnV-IL2 treatment mice demonstrated a stronger secondary expansion, indicating durability of AnnV-IL2 mediated responses. Our data supports the use of AnnV-IL2 to modulate antigen-specific T cell immunity and demonstrates that the PS-AnnV axis is a feasible mechanism to target diverse cargo to CD8 T cells.

Virus-Inspired Gold Nanorod-Mesoporous Silica Core-Shell Nanoparticles Integrated with tTF-EG3287 for Synergetic Tumor Photothermal Therapy and Selective Therapy for Vascular Thrombosis

Synergetic therapy includes the combination of two or more conventional therapeutic approaches and can be used for tumor treatment by combining the advantages and avoiding the drawbacks of each type of treatment. In the present study, truncated tissue factor (tTF)-EG3287 fusion protein-encapsulated gold nanorod (GNR)-virus-inspired mesoporous silica core-shell nanoparticles (vinyl hybrid silica nanoparticles; VSNP) (GNR@VSNP-tTF-EG3287) were synthesized to achieve synergetic therapy by utilizing selective vascular thrombosis therapy (SVTT) and photothermal therapy (PTT). By integrating the targeted coagulation activity of tTF-EG3287 and the high tumor ablation effect of GNR@VSNP, local hyperthermia could induce a high percentage of apoptosis of vascular endothelial cells by using near-infrared light. This provided additional phospholipid sites for tTF-EG3287 and enhanced its procoagulant activity in vitro. In addition, the nanoparticles, which had unique topological viral structures, exhibited superior cellular uptake properties leading to significant antitumor efficacy. The in vivo antitumor results further demonstrated an interaction between SVTT and PTT, whereas the synergetic therapy (SVTT and PTT) achieved an enhanced effect, which was superior to the respective treatment efficacy of each modality or the additive effect of their individual efficacies. In summary, the synthesized GNR@VSNP-tTF-EG3287 exerted synergetic effects and enhanced the antitumor efficiency by avoiding multiple injections and suboptimal administration. These effects simultaneously affected both tumor blood supply and cancer cell proliferation. The data suggested that the integration of SVTT induced by tTF-EG3287 and PTT could provide potential strategies for synergetic tumor therapy.

Biomimetic artificial cells to model the effect of membrane asymmetry on chemoresistance

We present a microfluidic platform that enables the formation of bespoke asymmetric droplet interface bilayers (DIBs) as artificial cell models from naturally-derived lipids. We use them to perform pharmacokinetic assays to quantify how lipid asymmetry affects the permeability of the chemotherapy drug doxorubicin. Previous attempts to model bilayer asymmetry with DIBs have relied on the use of synthetic lipids to achieve asymmetry. Use of natural lipids serves to increase the biomimetic nature of these artificial cells, showcasing the next step towards forming a true artificial cell membrane in vitro. Here we use our microfluidic platform to form biomimetic, asymmetric and symmetric DIBs, with their asymmetry quantified through their life-mimicking degree of curvature. We subsequently examine permeability of these membranes to doxorubicin, and reveal measurable differences in its pharmacokinetics induced by membrane asymmetry, highlighting another factor that potentially contributes to chemoresistance in some forms of cancer.

Selective Antifungal Activity and Fungal Biofilm Inhibition of Tryptophan Center Symmetrical Short Peptide

Candida albicans, an opportunistic fungus, causes dental caries and contributes to mucosal bacterial dysbiosis leading to a second infection. Furthermore, C.albicans forms biofilms that are resistant to medicinal treatment. To make matters worse, antifungal resistance has spread (albeit slowly) in this species. Thus, it has been imperative to develop novel, antifungal drug compounds. Herein, a peptide was engineered with the sequence of RRFSFWFSFRR-NH2; this was named P19. This novel peptide has been observed to exert disruptive effects on fungal cell membrane physiology. Our results showed that P19 displayed high binding affinity to lipopolysaccharides (LPS), lipoteichoic acids (LTA) and the plasma membrane phosphatidylinositol (PI), phosphatidylserine (PS), cardiolipin, and phosphatidylglycerol (PG), further indicating that the molecular mechanism of P19 was not associated with the receptor recognition, but rather related to competitive interaction with the plasma membrane. In addition, compared with fluconazole and amphotericin B, P19 has been shown to have a lower potential for resistance selection than established antifungal agents.

Novel Approaches of Dysregulating Lysosome Functions in Cancer Cells by Specific Drugs and Its Nanoformulations: A Smart Approach of Modern Therapeutics

The smart strategy of cancer cells to bypass the caspase-dependent apoptotic pathway has led to the discovery of novel anti-cancer approaches including the targeting of lysosomes. Recent discoveries observed that lysosomes perform far beyond just recycling of cellular waste, as these organelles are metabolically very active and mediate several signalling pathways to sense the cellular metabolic status. These organelles also play a significant role in mediating the immune system functions. Thus, direct or indirect lysosome-targeting with different drugs can be considered a novel therapeutic approach in different disease including cancer. Recently, some anticancer lysosomotropic drugs (eg, nortriptyline, siramesine, desipramine) and their nanoformulations have been engineered to specifically accumulate within these organelles. These drugs can enhance lysosome membrane permeabilization (LMP) or disrupt the activity of resident enzymes and protein complexes, like v-ATPase and mTORC1. Other anticancer drugs like doxorubicin, quinacrine, chloroquine and DQ661 have also been used which act through multi-target points. In addition, autophagy inhibitors, ferroptosis inducers and fluorescent probes have also been used as novel theranostic agents. Several lysosome-specific drug nanoformulations like mixed charge and peptide conjugated gold nanoparticles (AuNPs), Au-ZnO hybrid NPs, TPP-PEG-biotin NPs, octadecyl-rhodamine-B and cationic liposomes, etc. have been synthesized by diverse methods. These nanoformulations can target cathepsins, glucose-regulated protein 78, or other lysosome specific proteins in different cancers. The specific targeting of cancer cell lysosomes with drug nanoformulations is quite recent and faces tremendous challenges like toxicity concerns to normal tissues, which may be resolved in future research. The anticancer applications of these nanoformulations have led them up to various stages of clinical trials. Here in this review article, we present the recent updates about the lysosome ultrastructure, its cross-talk with other organelles, and the novel strategies of targeting this organelle in tumor cells as a recent innovative approach of cancer management.

The Evolution of Safe and Effective Coaguligands for Vascular Targeting and Precision Thrombosis of Solid Tumors and Vascular Malformations

In cardiovascular and cerebrovascular biology, control of thrombosis and the coagulation cascade in ischemic stroke, myocardial infarction, and other coagulopathies is the focus of significant research around the world. Ischemic stroke remains one of the largest causes of death and disability in developed countries. Preventing thrombosis and protecting vessel patency is the primary goal. However, utilization of the body’s natural coagulation cascades as an approach for targeted destruction of abnormal, disease-associated vessels and tissues has been increasing over the last 30 years. This vascular targeting approach, often termed “vascular infarction”, describes the deliberate, targeted delivery of a thrombogenic effector to diseased blood vessels with the aim to induce localized activation of the coagulation cascade and stable thrombus formation, leading to vessel occlusion and ablation. As systemic delivery of pro-thrombotic agents may cause consternation amongst traditional stroke researchers, proponents of the approach must suitably establish both efficacy and safety to take this field forward. In this review, we describe the evolution of this field and, with a focus on thrombogenic effectors, summarize the current literature with respect to emerging trends in “coaguligand” development, in targeted tumor vessel destruction, and in expansion of the approach to the treatment of brain vascular malformations.

Phosphatidylserine externalized on the colonic capillaries as a novel pharmacological target for IBD therapy

Inflammatory bowel disease (IBD) is a chronic and relapsing disorder for many people associated with poor health. Although there are some clinical drugs for IBD treatment, the development of effective therapeutics on IBD patients has always been necessary. Here, we show that externalized phosphatidylserine (PS) is observed on the surface of colonic capillaries. Annexin A5 (ANXA5) with high affinity for PS has a good targeting to the colon and effectively alleviates experimental colitis. In contrast, ANXA5 mutant (A5m) lacking the PS-binding ability, has no accumulation in the colon and no therapeutic effects on colitis. Mechanistic investigations indicate that ANXA5 reduces the inflammatory cell infiltration by inhibiting endothelial cell activation dependent on PS-binding ability. With the increasing of PS exposure on activated HUVECs (human umbilical vein endothelial cells), ANXA5 binding induces the internalization of TLR4 via PS-dependent endocytosis. We provide new insights on the molecular mechanism of ANXA5 for its anti-inflammatory effect. Our data suggest that PS-externalization is a potential target of ANXA5 aiming at targeted drug delivery (TDD) for IBD treatment.

The complex roles of efferocytosis in cancer development, metastasis, and treatment

When tumor cells are killed by targeted therapy, radiotherapy, or chemotherapy, they trigger their primary tumor by releasing pro-inflammatory cytokines. Microenvironmental interactions can also promote tumor heterogeneity and development. In this line, several immune cells within the tumor microenvironment, including macrophages, dendritic cells, regulatory T-cells, and CD8⁺ and CD4⁺ T cells, are involved in the clearance of apoptotic tumor cells through a process called efferocytosis. Although the efficiency of apoptotic tumor cell efferocytosis is positive under physiological conditions, there are controversies regarding its usefulness in treatment-induced apoptotic tumor cells (ATCs). Efferocytosis can show the limitation of cytotoxic treatments, such as chemotherapy and radiotherapy. Since cytotoxic treatments lead to extensive cell mortality, efferocytosis, and macrophage polarization toward an M2 phenotype, the immune response may get involved in tumor recurrence and metastasis. Tumor cells can use the anti-inflammatory effect of apoptotic tumor cell efferocytosis to induce an immunosuppressive condition that is tumor-tolerant. Since M2 polarization and efferocytosis are tumor-promoting processes, the receptors on macrophages act as potential targets for cancer therapy. Moreover, researchers have shown that efferocytosis-related molecules/pathways are potential targets for cancer therapy. These include phosphatidylserine and calreticulin, Tyro3, Axl, and Mer tyrosine kinase (MerTK), receptors of tyrosine kinase, indoleamine-2,3-dioxygenase 1, annexin V, CD47, TGF-β, IL-10, and macrophage phenotype switch are combined with conventional therapy, which can be more effective in cancer treatment. Thus, we set out to investigate the advantages and disadvantages of efferocytosis in treatment-induced apoptotic tumor cells.

Chemokines act as phosphatidylserine-bound "find-me" signals in apoptotic cell clearance

Removal of apoptotic cells is essential for maintenance of tissue homeostasis. Chemotactic cues termed "find-me" signals attract phagocytes toward apoptotic cells, which selectively expose the anionic phospholipid phosphatidylserine (PS) and other "eat-me" signals to distinguish healthy from apoptotic cells for phagocytosis. Blebs released by apoptotic cells can deliver find-me signals; however, the mechanism is poorly understood. Here, we demonstrate that apoptotic blebs generated in vivo from mouse thymus attract phagocytes using endogenous chemokines bound to the bleb surface. We show that chemokine binding to apoptotic cells is mediated by PS and that high affinity binding of PS and other anionic phospholipids is a general property of many but not all chemokines. Chemokines are positively charged proteins that also bind to anionic glycosaminoglycans (GAGs) on cell surfaces for presentation to leukocyte G protein-coupled receptors (GPCRs). We found that apoptotic cells down-regulate GAGs as they up-regulate PS on the cell surface and that PS-bound chemokines, unlike GAG-bound chemokines, are able to directly activate chemokine receptors. Thus, we conclude that PS-bound chemokines may serve as find-me signals on apoptotic vesicles acting at cognate chemokine receptors on leukocytes.

Exploiting Phagocytic Checkpoints in Nanomedicine: Applications in Imaging and Combination Therapies

Recent interest in cancer immunotherapy has largely been focused on the adaptive immune system, particularly adoptive T-cell therapy and immune checkpoint blockade (ICB). Despite improvements in overall survival and progression-free survival across multiple cancer types, neither cell-based therapies nor ICB results in durable disease control in the majority of patients. A critical component of antitumor immunity is the mononuclear phagocyte system and its role in both innate and adaptive immunity. The phagocytic functions of these cells have been shown to be modulated through multiple pathways, including the CD47-SIRPα axis, which is manipulated by cancer cells for immune evasion. In addition to CD47, tumors express a variety of other “don’t eat me” signals, including beta-2-microglobulin and CD24, and “eat me” signals, including calreticulin and phosphatidylserine. Therapies targeting these signals can lead to increased phagocytosis of cancer cells; however, because “don’t eat me” signals are markers of “self” on normal cells, treatment can result in negative off-target effects, such as anemia and B-cell depletion. Recent preclinical research has demonstrated the potential of nanocarriers to synergize with prophagocytic therapies, address the off-target effects, improve pharmacokinetics, and codeliver chemotherapeutics. The high surface area-to-volume ratio of nanoparticles paired with preferential size for passive targeting allows for greater accumulation of therapeutic cargo. In addition, nanomaterials hold promise as molecular imaging agents for the detection of phagocytic markers. This mini review highlights the unique capabilities of nanotechnology to expand the application and efficacy of immunotherapy through recently discovered phagocytotic checkpoint therapies.

Apoptosis Imaging in Oncology by Means of Positron Emission Tomography: A Review

To date, a wide variety of potential PET-apoptosis imaging radiopharmaceuticals targeting apoptosis-induced cell membrane asymmetry and acidification, as well as caspase 3 activation (substrates and inhibitors) have been developed with the purpose of rapidly assessing the response to treatment in cancer patients. Many of these probes were shown to specifically bind to their apoptotic target in vitro and their uptake to be enhanced in the in vivo-xenografted tumours in mice treated by means of chemotherapy, however, to a significantly variable degree. This may, in part, relate to the tumour model used given the fact that different tumour cell lines bear a different sensitivity to a similar chemotherapeutic agent, to differences in the chemotherapeutic concentration and exposure time, as well as to the different timing of imaging performed post-treatment. The best validated cell membrane acidification and caspase 3 targeting radioligands, respectively ¹⁸F-ML-10 from the Aposense family and the radiolabelled caspase 3 substrate ¹⁸F-CP18, have also been injected in healthy individuals and shown to bear favourable dosimetric and safety characteristics. However, in contrast to, for instance, the ^99mTc-HYNIC-Annexin V, neither of both tracers was taken up to a significant degree by the bone marrow in the healthy individuals under study. Removal of white and red blood cells from the bone marrow through apoptosis plays a major role in the maintenance of hematopoietic cell homeostasis. The major apoptotic population in normal bone marrow are immature erythroblasts. While an accurate estimate of the number of immature erythroblasts undergoing apoptosis is not feasible due to their unknown clearance rate, their number is likely substantial given the ineffective quote of the erythropoietic process described in healthy subjects. Thus, the clinical value of both ¹⁸F-ML-10 and ¹⁸F-CP18 for apoptosis imaging in cancer patients, as suggested by a small number of subsequent clinical phase I/II trials in patients suffering from primary or secondary brain malignancies using ¹⁸F-ML-10 and in an ongoing trial in patients suffering from cancer of the ovaries using ¹⁸F-CP18, remains to be proven and warrants further investigation.

Trial Watch: Monoclonal antibodies in cancer therapy

Since the advent of hybridoma technology, dating back to 1975, monoclonal antibodies have become an irreplaceable diagnostic and therapeutic tool for a wide array of human diseases. During the last 15 years, several monoclonal antibodies (mAbs) have been approved by FDA for cancer therapy. These mAbs are designed to (1) activate the immune system against tumor cells, (2) inhibit cancer cell-intrinsic signaling pathways, (3) bring toxins in the close proximity of cancer cells, or (4) interfere with the tumor-stroma interaction. More recently, major efforts have been made for the development of immunostimulatory mAbs that either enhance cancer-directed immune responses or limit tumor- (or therapy-) driven immunosuppression. Some of these antibodies, which are thought to facilitate tumor eradication by initiating or sustaining a tumor-specific immune response, have already entered clinical trials. In this Trial Watch, we will review and discuss the clinical progress of the most important mAbs that are have entered clinical trials after January 2008.

Axl and Mertk Receptors Cooperate to Promote Breast Cancer Progression by Combined Oncogenic Signaling and Evasion of Host Antitumor Immunity

Despite the promising clinical benefit of targeted and immune checkpoint blocking therapeutics, current strategies have limited success in breast cancer, indicating that additional inhibitory pathways are required to complement existing therapeutics. TAM receptors (Tyro-3, Axl, and Mertk) are often correlated with poor prognosis because of their capacities to sustain an immunosuppressive environment. Here, we ablate Axl on tumor cells using CRISPR/Cas9 gene editing, and by targeting Mertk in the tumor microenvironment (TME), we observed distinct functions of TAM as oncogenic kinases, as well as inhibitory immune receptors. Depletion of Axl suppressed cell intrinsic oncogenic properties, decreased tumor growth, reduced the incidence of lung metastasis and increased overall survival of mice when injected into mammary fat pad of syngeneic mice, and demonstrated synergy when combined with anti-PD-1 therapy. Blockade of Mertk function on macrophages decreased efferocytosis, altered the cytokine milieu, and resulted in suppressed macrophage gene expression patterns. Mertk-knockout mice or treatment with anti-Mertk-neutralizing mAb also altered the cellular immune profile, resulting in a more inflamed tumor environment with enhanced T-cell infiltration into tumors and T-cell-mediated cytotoxicity. The antitumor activity from Mertk inhibition was abrogated by depletion of cytotoxic CD8α T cells by using anti-CD8α mAb or by transplantation of tumor cells into B6.CB17-Prkdc SCID mice. Our data indicate that targeting Axl expressed on tumor cells and Mertk in the TME is predicted to have a combinatorial benefit to enhance current immunotherapies and that Axl and Mertk have distinct functional activities that impair host antitumor response. SIGNIFICANCE: This study demonstrates how TAM receptors act both as oncogenic tyrosine kinases and as receptors that mediate immune evasion in cancer progression.

Targeted Single-Walled Carbon Nanotubes for Photothermal Therapy Combined with Immune Checkpoint Inhibition for the Treatment of Metastatic Breast Cancer

The greatest contributors to cancer mortality are metastasis and the consequences of its treatment. Here, we present a novel treatment of metastatic breast cancer that combines photothermal therapy with targeted single-walled carbon nanotubes (SWCNTs) and immunostimulation with a checkpoint inhibitor. We find that the selective near-infrared photothermal ablation of primary orthotopic EMT6 breast tumors in syngeneic BALB/cJ mice using an annexin A5 (ANXA5) functionalized SWCNT bioconjugate synergistically enhances an anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4)-dependent abscopal response, resulting in an increased survival (55%) at 100 days after tumor inoculation. In comparison, there was no survival at 100 days for either photothermal therapy by itself or immunostimulation by itself. Prior to photothermal therapy, the SWCNT-ANXA5 bioconjugate was administered systemically at a relatively low dose of 1.2 mg/kg, where it then accumulated in tumor vasculature via ANXA5-dependent binding. During photothermal therapy, the average maximum temperature in the tumor reached 54 °C (duration 175 s). The mechanism of prolonged survival resulting from combinatorial photothermal ablation and immune stimulation was evaluated by flow cytometric quantification of splenic antitumoral immune effector cells and serum cytokine quantification.

Radioarsenic: A promising theragnostic candidate for nuclear medicine

Molecular imaging is a non-invasive process that enables the visualization, characterization, and quantitation of biological processes at the molecular and cellular level. With the emergence of theragnostic agents to diagnose and treat disease for personalized medicine there is a growing need for matched pairs of isotopes. Matched pairs offer the unique opportunity to obtain patient specific information from SPECT or PET diagnostic studies to quantitate in vivo function or receptor density to inform and tailor therapeutic treatment. There are several isotopes of arsenic that have emissions suitable for either or both diagnostic imaging and radiotherapy. Their half-lives are long enough to pair them with peptides and antibodies which take longer to reach maximum uptake to facilitate improved patient pharmacokinetics and dosimetry then can be obtained with shorter lived radionuclides. Arsenic-72 even offers availability from a generator that can be shipped to remote sites and thus enhances availability. Arsenic has a long history as a diagnostic agent, but until recently has suffered from limited availability, lack of suitable chelators, and concerns about toxicity have inhibited its use in nuclear medicine. However, new production methods and novel chelators are coming online and the use of radioarsenic in the pico and nanomolar scale is well below the limits associated with toxicity. This manuscript will review the production routes, separation chemistry, radiolabeling techniques and in vitro/in vivo studies of three medically relevant isotopes of arsenic (arsenic-74, arsenic-72, and arsenic-77).

Lipidomics investigations into the tissue phospholipidomic landscape of invasive ductal carcinoma of the breast

The need of identifying alternative therapeutic targets for invasive ductal carcinoma (IDC) of the breast with high specificity and sensitivity for effective therapeutic intervention is crucial for lowering the risk of fatality. Lipidomics has emerged as a key area for the discovery of potential candidates owing to its several shared pathways between cancer cell proliferation and survival. In the current study, we performed comparative phospholipidomic analysis of IDC, benign and control tissue samples of the breast to identify the significant lipid alterations associated with malignant transformation. A total of 33 each age-matched tissue samples from malignant, benign and control were analyzed to identify the altered phospholipids by using liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM/MS). A combination of univariate and multivariate statistical approaches was used to select the phospholipid species with the highest contribution in group segregation. Furthermore, these altered phospholipids were structurally confirmed by tandem mass spectrometry. A total of 244 phospholipids were detected consistently at quantifiable levels, out of which 32 were significantly altered in IDC of the breast. Moreover, in pairwise comparison of IDC against benign and control samples, 11 phospholipids were found to be significantly differentially expressed. Particularly, LPI 20:3, PE (22:1/22:2), LPE 20:0 and PC (20:4/22:4) were observed to be most significantly associated with IDC tissue samples. Apart from that, we also identified that long-chain unsaturated fatty acids were enriched in the IDC tissue samples as compared to benign and control samples, indicating its possible association with the invasive phenotype.

Materials promoting viral gene delivery

Therapeutic viral gene delivery is an emerging technology which aims to correct genetic mutations by introducing new genetic information to cells either to correct a faulty gene or to initiate cell death in oncolytic treatments. In recent years, significant scientific progress has led to several clinical trials resulting in the approval of gene therapies for human treatment. However, successful therapies remain limited due to a number of challenges such as inefficient cell uptake, low transduction efficiency (TE), limited tropism, liver toxicity and immune response. To adress these issues and increase the number of available therapies, additives from a broad range of materials like polymers, peptides, lipids, nanoparticles, and small molecules have been applied so far. The scope of this review is to highlight these selected delivery systems from a materials perspective.

Cell Death in the Tumor Microenvironment: Implications for Cancer Immunotherapy

The physiological fate of cells that die by apoptosis is their prompt and efficient removal by efferocytosis. During these processes, apoptotic cells release intracellular constituents that include purine nucleotides, lysophosphatidylcholine (LPC), and Sphingosine-1-phosphate (S1P) that induce migration and chemo-attraction of phagocytes as well as mitogens and extracellular membrane-bound vesicles that contribute to apoptosis-induced compensatory proliferation and alteration of the extracellular matrix and the vascular network. Additionally, during efferocytosis, phagocytic cells produce a number of anti-inflammatory and resolving factors, and, together with apoptotic cells, efferocytic events have a homeostatic function that regulates tissue repair. These homeostatic functions are dysregulated in cancers, where, aforementioned events, if not properly controlled, can lead to cancer progression and immune escape. Here, we summarize evidence that apoptosis and efferocytosis are exploited in cancer, as well as discuss current translation and clinical efforts to harness signals from dying cells into therapeutic strategies.

Mitochondria membrane transformations in colon and prostate cancer and their biological implications

Mitochondria have emerged as important determinants in cancer progression and malignancy. However, the role of mitochondrial membranes in cancer onset and progression has not been thoroughly investigated. This study compares the structural and functional properties of mitochondrial membranes in prostate and colon cancer cells in comparison to normal mitochondria, and possible therapeutic implications of these membrane changes. Specifically, isolation of cell mitochondria and preparation of inverted sub-mitochondrial particles (SMPs) illuminated significant cancer-induced modulations of membrane lipid compositions, fluidity, and activity of cytochrome c oxidase, one of the key mitochondrial enzymes. The experimental data further show that cancer-associated membrane transformations may account for mitochondria targeting by betulinic acid and resveratrol, known anti-cancer molecules. Overall, this study probes the relationship between cancer and mitochondrial membrane transformations, underlying a potential therapeutic significance for mitochondrial membrane targeting in cancer.

Targeting phosphatidylserine for Cancer therapy: prospects and challenges

Cancer is a leading cause of mortality and morbidity worldwide. Despite major improvements in current therapeutic methods, ideal therapeutic strategies for improved tumor elimination are still lacking. Recently, immunotherapy has attracted much attention, and many immune-active agents have been approved for clinical use alone or in combination with other cancer drugs. However, some patients have a poor response to these agents. New agents and strategies are needed to overcome such deficiencies. Phosphatidylserine (PS) is an essential component of bilayer cell membranes and is normally present in the inner leaflet. In the physiological state, PS exposure on the external leaflet not only acts as an engulfment signal for phagocytosis in apoptotic cells but also participates in blood coagulation, myoblast fusion and immune regulation in nonapoptotic cells. In the tumor microenvironment, PS exposure is significantly increased on the surface of tumor cells or tumor cell-derived microvesicles, which have innate immunosuppressive properties and facilitate tumor growth and metastasis. To date, agents targeting PS have been developed, some of which are under investigation in clinical trials as combination drugs for various cancers. However, controversial results are emerging in laboratory research as well as in clinical trials, and the efficiency of PS-targeting agents remains uncertain. In this review, we summarize recent progress in our understanding of the physiological and pathological roles of PS, with a focus on immune suppressive features. In addition, we discuss current drug developments that are based on PS-targeting strategies in both experimental and clinical studies. We hope to provide a future research direction for the development of new agents for cancer therapy.

The impact of blue light in monolayers representing tumorigenic and nontumorigenic cell membranes containing epigallocatechin-3-gallate

Natural products such as epigallocatechin-3-gallate (EGCG) have been suggested for complementary treatments of cancer, since they lower toxic side effects of anticancer drugs, and possess anti-inflammatory and antioxidant properties that inhibit carcinogenesis. Their effects on cancer cells depend on interactions with the membrane, which is the motivation to investigate Langmuir monolayers as simplified membrane models. In this study, EGCG was incorporated in zwitterionic dipalmitoyl phosphatidyl choline (DPPC) and anionic dipalmitoyl phosphatidyl serine (DPPS) Langmuir monolayers to simulate healthy and cancer cells membranes, respectively. EGCG induces condensation in surface pressure isotherms for both DPPC and DPPS monolayers, interacting mainly via electrostatic forces and hydrogen bonding with the choline and phosphate groups of the phospholipids, according to data from polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). Both monolayers become more compressible upon interaction with EGCG, which may be correlated to the synergy between EGCG and anticancer drugs reported in the literature. The interaction with EGCG is stronger for DPPC, leading to stronger morphological changes in Brewster angle microscopy (BAM) images and higher degree of condensation in the surface pressure isotherms. The changes induced by blue irradiation on DPPC and DPPS monolayers were largely precluded when EGCG was incorporated, thus confirming its antioxidant capacity for both types of membrane.

Discrimination of live and dead cells with two different sets of signals and unique application in vivo imaging

Discriminating living and dead cells is of great significance for the study of apoptosis. In this work, we have developed a unique fluorescent probe (RPIC) for discriminating live and dead cells with duel-channel fluorescence imaging under double excitation and double emission mode. Dead cells treated with RPIC shows weak fluorescence signals in red channel, however, strong fluorescence signals are appeared in red channel in live cells. Weak and strong green fluorescence signals present at live cells and dead cells, respectively. Moreover, RPIC can detect successfully apoptosis of cancer cells. For in-vivo imaging, RPIC can discriminate successfully live and dead zebrafish with the same method. More interestingly, it is found that RPIC possesses the ability of discriminating normal mice and tumor mice.

TIMs, TAMs, and PS- antibody targeting: implications for cancer immunotherapy

Immunotherapy for cancer is making impressive strides at improving survival of a subset of cancer patients. To increase the breadth of patients that benefit from immunotherapy, new strategies that combat the immunosuppressive microenvironment of tumors are needed. Phosphatidylserine (PS) signaling is exploited by tumors to enhance tumor immune evasion and thus strategies to inhibit PS-mediated immune suppression have potential to increase the efficacy of immunotherapy. PS is a membrane lipid that flips to the outer surface of the cell membrane during apoptosis and/or cell stress. Externalized PS can drive efferocytosis or engage PS receptors (PSRs) to promote local immune suppression. In the tumor microenvironment (TME) PS-mediated immune suppression is often termed apoptotic mimicry. Monoclonal antibodies (mAbs) targeting PS or PSRs have been developed and are in preclinical and clinical testing. The TIM (T-cell/transmembrane, immunoglobulin, and mucin) and TAM (Tyro3, AXL, and MerTK) family of receptors are PSRs that have been shown to drive PS-mediated immune suppression in tumors. This review will highlight the development of mAbs targeting PS, TIM-3 and the TAM receptors.