Molecular cloning of Porimin, a novel cell surface receptor mediating oncotic cell death

Unravelling oncosis: morphological and molecular insights into a unique cell death pathway

Programmed cell death (PCD) is a fundamental biological process for maintaining cellular equilibrium and regulating development, health, and disease across all living organisms. Among the various types of PCD, apoptosis plays a pivotal role in numerous diseases, notably cancer. Cancer cells frequently develop mechanisms to evade apoptosis, increasing resistance to standard chemotherapy treatments. This resistance has prompted extensive research into alternative mechanisms of programmed cell death. One such pathway is oncosis, characterized by significant energy consumption, cell swelling, dilation of the endoplasmic reticulum, mitochondrial swelling, and nuclear chromatin aggregation. Recent research suggests that oncosis can impact conditions such as chemotherapeutic cardiotoxicity, myocardial ischemic injury, stroke, and cancer, mediated by specific oncosis-related proteins. In this review, we provide a detailed examination of the morphological and molecular features of oncosis and discuss various natural or small molecule compounds that can induce this type of cell death. Additionally, we summarize the current understanding of the molecular mechanisms underlying oncosis and its role in both normal physiology and pathological conditions. These insights aim to illuminate future research directions and propose innovative strategies for leveraging oncosis as a therapeutic tool against human diseases and cancer resistance.

A Cyclometalated Ruthenium(II) Complex Induces Oncosis for Synergistic Activation of Innate and Adaptive Immunity

An optimal cancer chemotherapy regimen should effectively address the drug resistance of tumors while eliciting antitumor-immune responses. Research has shown that non-apoptotic cell death, such as pyroptosis and ferroptosis, can enhance the immune response. Despite this, there has been limited investigation and reporting on the mechanisms of oncosis and its correlation with immune response. Herein, we designed and synthesized a Ru(II) complex that targeted the nucleus and mitochondria to induce cell oncosis. Briefly, the Ru(II) complex disrupts the nucleus and mitochondria DNA, which active polyADP-ribose polymerase 1, accompanied by ATP consumption and porimin activation. Concurrently, mitochondrial damage and endoplasmic reticulum stress result in the release of Ca2+ ions and increased expression of Calpain 1. Subsequently, specific pore proteins porimin and Calpain 1 promote cristae destruction or vacuolation, ultimately leading to cell membrane rupture. The analysis of RNA sequencing demonstrates that the Ru(II) complex can initiate the oncosis-associated pathway and activate both innate and adaptive immunity. In vivo experiments have confirmed that oncosis promotes dendritic cell maturation and awakens adaptive cytotoxic T lymphocytes but also activates the innate immune by inducing the polarization of macrophages towards an M1 phenotype.

Arnicolide D induces endoplasmic reticulum stress-mediated oncosis via ATF4 and CHOP in hepatocellular carcinoma cells

Endoplasmic reticulum (ER) stress can trigger various cell death mechanisms beyond apoptosis, providing promise in cancer treatment. Oncosis, characterized by cellular swelling and increased membrane permeability, represents a non-apoptotic form of cell death. In our study, we discovered that Arnicolide D (AD), a natural sesquiterpene lactone compound, induces ER stress-mediated oncosis in hepatocellular carcinoma (HCC) cells, and this process is reactive oxygen species (ROS)-dependent. Furthermore, we identified the activation of the PERK-eIF2α-ATF4-CHOP pathway during ER stress as a pivotal factor in AD-induced oncosis. Notably, the protein synthesis inhibitor cycloheximide (CHX) was found to effectively reverse AD-induced oncosis, suggesting ATF4 and CHOP may hold crucial roles in the induction of oncosis by AD. These proteins play a vital part in promoting protein synthesis during ER stress, ultimately leading to cell death. Subsequent studies, in where we individually or simultaneously knocked down ATF4 and CHOP in HCC cells, provided further confirmation of their indispensable roles in AD-induced oncosis. Moreover, additional animal experiments not only substantiated AD's ability to inhibit HCC tumor growth but also solidified the essential role of ER stress-mediated and ROS-dependent oncosis in AD's therapeutic potential. In summary, our research findings strongly indicate that AD holds promise as a therapeutic agent for HCC by its ability to induce oncosis.

Lysosome-targeted ruthenium(II) complex encapsulated with pluronic® F-127 induces oncosis in A549 cells

Transition metal complexes with characteristics of unique packaging in nanoparticles and remarkable cancer cell cytotoxicity have emerged as potential alternatives to platinum-based antitumor drugs. Here we report the synthesis, characterization, and antitumor activities of three new Ruthenium complexes that introduce 5-fluorouracil-derived ligands. Notably, encapsulation of one such metal complex, Ru3, within pluronic® F-127 micelles (Ru3-M) significantly enhanced Ru3 cytotoxicity toward A549 cells by a factor of four. To determine the mechanisms underlying Ru3-M cytotoxicity, additional in vitro experiments were conducted that revealed A549 cell treatment with lysosome-targeting Ru3-M triggered oxidative stress, induced mitochondrial membrane potential depolarization, and drastically reduced intracellular ATP levels. Taken together, these results demonstrated that Ru3-M killed cells mainly via a non-apoptotic pathway known as oncosis, as evidenced by observed Ru3-M-induced cellular morphological changes including cytosolic flushing, cell swelling, and cytoplasmic vacuolation. In turn, these changes together caused cytoskeletal collapse and activation of porimin and calpain1 proteins with known oncotic functions that distinguished this oncotic process from other cell death processes. In summary, Ru3-M is a potential anticancer agent that kills A549 cells via a novel mechanism involving Ru(II) complex triggering of cell death via oncosis.

Dihydrotanshinone Triggers Porimin-Dependent Oncosis by ROS-Mediated Mitochondrial Dysfunction in Non-Small-Cell Lung Cancer

Lung cancer is one of the leading causes of cancer death. Non-small-cell lung cancer (NSCLC) accounts for the majority of lung cancer diagnoses. Dihydrotanshinone (DHT) is a compound extract from Salvia miltiorrhiza, which has favorable anti-inflammatory and anti-cancer activities. However, the role of DHT in NSCLC has not been fully studied. The anti-cancer drugs used for treating lung cancer often lead to apoptosis; however, the drug resistance of apoptosis restricts the effect of these drugs. Oncosis is a passive form of cell death that is different from apoptosis. It is characterized by cell swelling, and Porimin is a specific marker for oncosis. In this study, the role of DHT in mediating oncosis in A549 cells was investigated. In vitro, the MTS assay was used to detect cell activity after DHT treatment. Microscopy and electron microscopy were used to observe cell morphology changes. Western blotting was used to detect protein expression. Flow cytometry was used to detect intracellular reactive oxygen species (ROS) level, calcium ion (Ca2+) level, and cell mortality. The intracellular Lactic dehydrogenase (LDH) level was detected by an LDH detection kit after DHT treatment. The ATP level was detected using an ATP detection kit. In vivo, Lewis lung cancer (LLC) xenograft mice were used to evaluate the anti-tumor effect of DHT. Hematoxylin and eosin (HE) staining was used to detect the pathology of lung cancer tumors. The detection of Porimin in the tumor tissues of the mice after DHT administration was assessed by immunohistochemistry (IHC). The results of this study showed that DHT treatment changed the cell morphology; destroyed the mitochondrial structure; increased the expression of Porimin; increased the levels of LDH, ROS, and Ca2+; decreased the mitochondrial membrane potential and ATP level; and played an anti-tumor role in vitro by mediating oncosis in A549 cells. The in vivo studies showed that DHT could effectively inhibit tumor growth. The results of protein detection and IHC detection in the tumor tissues showed that the expression of Porimin was increased and that oncosis occurred in the tumor tissues of mice. DHT triggered Porimin-dependent oncosis by ROS-mediated mitochondrial dysfunction in NSCLC. The in vivo studies showed that DHT could inhibit tumor growth in LLC xenograft mice by triggering oncosis. This study indicates the potential for DHT to treat NSCLC.

TMEM123 a key player in immune surveillance of colorectal cancer

Colorectal cancer (CRC) is a leading cause of cancer-associated death. In the tumor site, the interplay between effector immune cells and cancer cells determines the balance between tumor elimination or outgrowth. We discovered that the protein TMEM123 is over-expressed in tumour-infiltrating CD4 and CD8 T lymphocytes and it contributes to their effector phenotype. The presence of infiltrating TMEM123+ CD8+ T cells is associated with better overall and metastasis-free survival. TMEM123 localizes in the protrusions of infiltrating T cells, it contributes to lymphocyte migration and cytoskeleton organization. TMEM123 silencing modulates the underlying signaling pathways dependent on the cytoskeletal regulator WASP and the Arp2/3 actin nucleation complex, which are required for synaptic force exertion. Using tumoroid-lymphocyte co-culture assays, we found that lymphocytes form clusters through TMEM123, anchoring to cancer cells and contributing to their killing. We propose an active role for TMEM123 in the anti-cancer activity of T cells within tumour microenvironment.

Self-Immolative Photosensitizers for Self-Reported Cancer Phototheranostics

Photosensitizers to precise target and change fluorescence upon light illumination could accurately self-report where and when the photosensitizers work, enabling us to visualize the therapeutic process and precisely regulate treatment outcomes, which is the unremitting pursuit of precision and personalized medicine. Here, we report self-immolative photosensitizers by adopting a strategy of light-manipulated oxidative cleavage of C═C bonds that can generate a burst of reactive oxygen species, to cleave to release self-reported red-emitting products and trigger nonapoptotic cell oncosis. Strong electron-withdrawing groups are found to effectively suppress the C═C bond cleavage and phototoxicity via studying the structure-activity relationship, allowing us to elaborate NG1-NG5 that could temporarily inactivate the photosensitizer and quench the fluorescence by different glutathione (GSH)-responsive groups. Thereinto, NG2 with 2-cyano-4-nitrobenzene-1-sulfonyl group displays excellent GSH responsiveness than the other four. Surprisingly, NG2 shows better reactivity with GSH in weakly acidic condition, which inspires the application in weakly acidic tumor microenvironment where GSH elevates. To this end, we further synthesize NG-cRGD by anchoring integrin α_vβ₃ binding cyclic pentapeptide (cRGD) for tumor targeting. In A549 xenografted tumor mice, NG-cRGD successfully deprotects to restore near-infrared fluorescence because of elevated GSH in tumor site, which is subsequently cleaved upon light irradiation releasing red-emitting products to report photosensitizer working, while effectively ablating tumors via triggered oncosis. The advanced self-immolative organic photosensitizer may accelerate the development of self-reported phototheranostics in future precision oncology.

Structural, topological, and functional characterization of transmembrane proteins TMEM213, 207, 116, 72 and 30B provides a potential link to ccRCC etiology

Due to their involvement in the development of various cancers Transmembrane Proteins (TMEMs) are the focus of many recent studies. Previously we reported TMEM de-regulation in clear cell Renal Cell Carcinoma (ccRCC) with TMEM213, 207, 116, 72 and 30B being among the most downregulated on mRNA level. TMEM down-regulation was also more pronounced in advanced ccRCC tumors and was potentially linked to clinical parameters such as: metastasis (TMEM72 and 116), Fuhrman grade (TMEM30B) and overall survival (TMEM30B). To further investigate these findings, first, we set off to prove experimentally that selected TMEMs are indeed membrane-bound as predicted in silico, we verified the presence of signaling peptides on their N-termini, orientation of TMEMs within the membrane and validated their predicted cellular localization. To investigate the potential role of selected TMEMs in cellular processes overexpression studies in HEK293 and HK-2 cell lines were carried out. Additionally, we tested TMEM isoform expression in ccRCC tumors, identified mutations in TMEM genes and examined chromosomal aberrations in their loci. We confirmed the membrane-bound status of all selected TMEMs, assigned TMEM213, and 207 to early endosomes, TMEM72 to early endosomes and plasma membrane, TMEM116 and 30B to the endoplasmic reticulum. The N-terminus of TMEM213 was found to be exposed to the cytoplasm, the C-terminus of TMEM207, 116 and 72 were directed toward the cytoplasm, and both termini of TMEM30B faced the cytoplasm. Interestingly, TMEM mutations and chromosomal aberrations were infrequent in ccRCC tumors, yet we identified potentially damaging mutations in TMEM213 and TMEM30B and found deletions in the TMEM30B locus in nearly 30% of the tumors. Overexpression studies suggested selected TMEMs may take part in carcinogenesis processes such as cell adhesion, regulation of epithelial cell proliferation, and regulation of adaptive immune response, which could indicate a link to the development and progression of ccRCC.

SILAC-based quantitative proteomics and microscopy analysis of cancer cells treated with the N-glycolyl GM3-specific anti-tumor antibody 14F7

Cancer immunotherapy represents a promising approach to specifically target and treat cancer. The most common mechanisms by which monoclonal antibodies kill cells include antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity and apoptosis, but also other mechanisms have been described. 14F7 is an antibody raised against the tumor-associated antigen NeuGc GM3, which was previously reported to kill cancer cells without inducing apoptotic pathways. The antibody was reported to induce giant membrane lesions in tumor cells, with apparent changes in the cytoskeleton. Here, we investigated the effect of humanized 14F7 on HeLa cells using stable isotope labeling with amino acids in cell culture (SILAC) in combination with LC-MS and live cell imaging. 14F7 did not kill the HeLa cells, however, it caused altered protein expression (MS data are available via ProteomeXchange with identifier PXD024320). Several cytoskeletal and nucleic-acid binding proteins were found to be strongly down-regulated in response to antibody treatment, suggesting how 14F7 may induce membrane lesions in cells that contain higher amounts of NeuGc GM3. The altered expression profile identified in this study thus contributes to an improved understanding of the unusual killing mechanism of 14F7.

iPCD: A Comprehensive Data Resource of Regulatory Proteins in Programmed Cell Death

Programmed cell death (PCD) is an essential biological process involved in many human pathologies. According to the continuous discovery of new PCD forms, a large number of proteins have been found to regulate PCD. Notably, post-translational modifications play critical roles in PCD process and the rapid advances in proteomics have facilitated the discovery of new PCD proteins. However, an integrative resource has yet to be established for maintaining these regulatory proteins. Here, we briefly summarize the mainstream PCD forms, as well as the current progress in the development of public databases to collect, curate and annotate PCD proteins. Further, we developed a comprehensive database, with integrated annotations for programmed cell death (iPCD), which contained 1,091,014 regulatory proteins involved in 30 PCD forms across 562 eukaryotic species. From the scientific literature, we manually collected 6493 experimentally identified PCD proteins, and an orthologous search was then conducted to computationally identify more potential PCD proteins. Additionally, we provided an in-depth annotation of PCD proteins in eight model organisms, by integrating the knowledge from 102 additional resources that covered 16 aspects, including post-translational modification, protein expression/proteomics, genetic variation and mutation, functional annotation, structural annotation, physicochemical property, functional domain, disease-associated information, protein–protein interaction, drug–target relation, orthologous information, biological pathway, transcriptional regulator, mRNA expression, subcellular localization and DNA and RNA element. With a data volume of 125 GB, we anticipate that iPCD can serve as a highly useful resource for further analysis of PCD in eukaryotes.

Osmium(VI) nitride triggers mitochondria-induced oncosis and apoptosis

We report a new osmium(VI) nitrido complex bearing a nonplanar tetradentate ligand with potent anticancer activity. This complex causes mitochondrial damage, which induces liver cancer cell death via oncosis and apoptosis. This is the first osmium-based anticancer candidate that induces oncosis.

The concept of intrinsic versus extrinsic apoptosis

Regulated cell death is a vital and dynamic process in multicellular organisms that maintains tissue homeostasis and eliminates potentially dangerous cells. Apoptosis, one of the better-known forms of regulated cell death, is activated when cell-surface death receptors like Fas are engaged by their ligands (the extrinsic pathway) or when BCL-2-family pro-apoptotic proteins cause the permeabilization of the mitochondrial outer membrane (the intrinsic pathway). Both the intrinsic and extrinsic pathways of apoptosis lead to the activation of a family of proteases, the caspases, which are responsible for the final cell demise in the so-called execution phase of apoptosis. In this review, I will first discuss the most common types of regulated cell death on a morphological basis. I will then consider in detail the molecular pathways of intrinsic and extrinsic apoptosis, discussing how they are activated in response to specific stimuli and are sometimes overlapping. In-depth knowledge of the cellular mechanisms of apoptosis is becoming more and more important not only in the field of cellular and molecular biology but also for its translational potential in several pathologies, including neurodegeneration and cancer.

Potent antitumor activity of a glutamyltransferase-derived peptide via an activation of oncosis pathway

Hepatocellular carcinoma (HCC) still presents poor prognosis with high mortality rate, despite of the improvement in the management. The challenge for precision treatment was due to the fact that little targeted therapeutics are available for HCC. Recent studies show that metabolic and circulating peptides serve as endogenous switches for correcting aberrant cellular plasticity. Here we explored the antitumor activity of low molecular components in human umbilical serum and identified a high abundance peptide VI-13 by peptidome analysis, which was recognized as the part of glutamyltransferase signal peptide. We modified VI-13 by inserting four arginines and obtained an analog peptide VI-17 to improve its solubility. Our analyses showed that the peptide VI-17 induced rapid context-dependent cell death, and exhibited a higher sensitivity on hepatoma cells, which is attenuated by polyethylene glycol but not necrotic inhibitors such as z-VAD-fmk or necrostatin-1. Morphologically, VI-17 induced cell swelling, blebbing and membrane rupture with release of cellular ATP and LDH into extracellular media, which is hallmark of oncotic process. Mechanistically, VI-17 induced cell membrane pore formation, degradation of α-tubulin via influx of calcium ion. These results indicated that the novel peptide VI-17 induced oncosis in HCC cells, which could serve as a promising lead for development of therapeutic intervention of HCC.

Identification of the SHREK Family of Proteins as Broad-Spectrum Host Antiviral Factors

Mucins and mucin-like molecules are highly glycosylated, high-molecular-weight cell surface proteins that possess a semi-rigid and highly extended extracellular domain. P-selectin glycoprotein ligand-1 (PSGL-1), a mucin-like glycoprotein, has recently been found to restrict HIV-1 infectivity through virion incorporation that sterically hinders virus particle attachment to target cells. Here, we report the identification of a family of antiviral cellular proteins, named the Surface-Hinged, Rigidly-Extended Killer (SHREK) family of virion inactivators (PSGL-1, CD43, TIM-1, CD34, PODXL1, PODXL2, CD164, MUC1, MUC4, and TMEM123) that share similar structural characteristics with PSGL-1. We demonstrate that SHREK proteins block HIV-1 infectivity by inhibiting virus particle attachment to target cells. In addition, we demonstrate that SHREK proteins are broad-spectrum host antiviral factors that block the infection of diverse viruses such as influenza A. Furthermore, we demonstrate that a subset of SHREKs also blocks the infectivity of a hybrid alphavirus-SARS-CoV-2 (Ha-CoV-2) pseudovirus. These results suggest that SHREK proteins may be a part of host innate immunity against enveloped viruses.

PORIMIN: The key to (+)-Usnic acid-induced liver toxicity and oncotic cell death in normal human L02 liver cells

ETHNOPHARMACOLOGICAL RELEVANCE

Usnic acid (UA) is one of the well-known lichen metabolites that induces liver injury. It is mainly extracted from Usnea longissima and U. diffracta in China or from other lichens in other countries. U. longissima has been used as traditional Chinese medicine for treatment of cough, pain, indigestion, wound healing and infection. More than 20 incidences with hepatitis and liver failure have been reported by the US Food and Drug Administration since 2000. UA is an uncoupler of oxidative phosphorylation causing glutathione and ATP depletion. Previous histological studies observed extensive cell and organelle swellings accompanied with hydrotropic vacuolization of hepatocytes.

AIM OF THE STUDY

This study was to investigate the mechanism of UA-induced liver toxicity in normal human L02 liver cells and ICR mice using various techniques, such as immunoblotting and siRNA transfection.

MATERIALS AND METHODS

Assays were performed to evaluate the oxidative stress and levels of GSH, MDA and SOD. Double flouresencence staining was used for the detection of apoptotic cell death. The protein expressions, such as glutathione S transferase, glutathione reductase, glutathione peroxidase 4, catalase, c-Jun N-terminal protein kinase, caspases, gastamin-D and porimin were detected by Western blotting. Comparisons between transfected and non-transfected cells were applied for the elucidation of the role of porimin in UA-induced hepatotoxicity. Histopathological examination of mice liver tissue, serum total bilirubin and hepatic enzymes of alanine aminotransferase and aspatate aminotransferase were also studied.

RESULTS

The protein expressions of glutathione reductase, glutathione S transferase and glutathione peroxidase-4 were increased significantly in normal human L02 liver cells. Catalase expression was diminished in dose-dependent manner. Moreover, (+)-UA did not induce the activation of caspase-3, caspase-1 or gasdermin-D. No evidence showed the occurrence of pyroptosis. However, the porimin expressions were increased significantly. In addition, (+)-UA caused no cytotoxicity in the porimin silencing L02 cells.

CONCLUSIONS

In conclusion, (+)-UA induces oncotic L02 cell death via increasing protein porimin and the formation of irreversible membrane pores. This may be the potential research area for future investigation in different aspects especially bioactivity and toxicology.

Comparative Cell Surface Proteomic Analysis of the Primary Human T Cell and Monocyte Responses to Type I Interferon

The cellular response to interferon (IFN) is essential for antiviral immunity, IFN-based therapy and IFN-related disease. The plasma membrane (PM) provides a critical interface between the cell and its environment, and is the initial portal of entry for viruses. Nonetheless, the effect of IFN on PM proteins is surprisingly poorly understood, and has not been systematically investigated in primary immune cells. Here, we use multiplexed proteomics to quantify IFNα2a-stimulated PM protein changes in primary human CD14+ monocytes and CD4+ T cells from five donors, quantifying 606 and 482 PM proteins respectively. Comparison of cell surface proteomes revealed a remarkable invariance between donors in the overall composition of the cell surface from each cell type, but a marked donor-to-donor variability in the effects of IFNα2a. Furthermore, whereas only 2.7% of quantified proteins were consistently upregulated by IFNα2a at the surface of CD4+ T cells, 6.8% of proteins were consistently upregulated in primary monocytes, suggesting that the magnitude of the IFNα2a response varies according to cell type. Among these differentially regulated proteins, we found the viral target Endothelin-converting enzyme 1 (ECE1) to be an IFNα2a-stimulated protein exclusively upregulated at the surface of CD4+ T cells. We therefore provide a comprehensive map of the cell surface of IFNα2a-stimulated primary human immune cells, including previously uncharacterized interferon stimulated genes (ISGs) and candidate antiviral factors.

Identification of the SHREK family of proteins as broad-spectrum host antiviral factors

Mucins and mucin-like molecules are highly glycosylated, high-molecular-weight cell surface proteins that possess a semi-rigid and highly extended extracellular domain. P-selectin glycoprotein ligand-1 (PSGL-1), a mucin-like glycoprotein, has recently been found to restrict HIV-1 infectivity through virion incorporation that sterically hinders virus particle attachment to target cells. Here, we report the identification of a family of antiviral cellular proteins, named the Surface-Hinged, Rigidly-Extended Killer (SHREK) family of virion inactivators (PSGL-1, CD43, TIM-1, CD34, PODXL1, PODXL2, CD164, MUC1, MUC4, and TMEM123), that share similar structural characteristics with PSGL-1. We demonstrate that SHREK proteins block HIV-1 infectivity by inhibiting virus particle attachment to target cells. In addition, we demonstrate that SHREK proteins are broad-spectrum host antiviral factors that block the infection of diverse viruses such as influenza A. Furthermore, we demonstrate that a subset of SHREKs also blocks the infectivity of a hybrid alphavirus-SARS-CoV-2 virus-like particle. These results suggest that SHREK proteins may be a part of host innate immunity against enveloped viruses.

Inhibition of clathrin-mediated endocytosis by knockdown of AP-2 leads to alterations in the plasma membrane proteome

In eukaryotic cells, clathrin-mediated endocytosis (CME) is a central pathway for the internalization of proteins from the cell surface, thereby contributing to the maintenance of the plasma membrane protein composition. A key component for the formation of endocytic clathrin-coated vesicles (CCVs) is AP-2, as it sequesters cargo membrane proteins, recruits a multitude of other endocytic factors and initiates clathrin polymerization. Here, we inhibited CME by depletion of AP-2 and explored the consequences for the plasma membrane proteome. Quantitative analysis revealed accumulation of major constituents of the endosomal-lysosomal system reflecting a block in retrieval by compensatory CME. The noticeable enrichment of integrins and blockage of their turnover resulted in severely impaired cell migration. Rare proteins such as the anti-cancer drug target CA9 and tumor markers (CD73, CD164, CD302) were significantly enriched. The AP-2 knockdown attenuated the global endocytic capacity, but clathrin-independent entry pathways were still operating, as indicated by persistent internalization of specific membrane-spanning and GPI-anchored receptors (PVR, IGF1R, CD55, TNAP). We hypothesize that blocking AP-2 function and thus inhibiting CME may be a novel approach to identify new druggable targets, or to increase their residence time at the plasma membrane, thereby increasing the probability for efficient therapeutic intervention.

Review: Usnic acid-induced hepatotoxicity and cell death

Increasing prevalence of herbal and dietary supplement-induced hepatotoxicity has been reported worldwide. Usnic acid (UA) is a well-known hepatotoxin derived from lichens. Since 2000, more than 20 incident reports have been received by the US Food and Drug Administration after intake of UA containing dietary supplement resulting in severe complications. Scientists and clinicians have been studying the cause, prevention and treatment of UA-induced hepatotoxicity. It is now known that UA decouples oxidative phosphorylation, induces adenosine triphosphate (ATP) depletion, decreases glutathione (GSH), and induces oxidative stress markedly leading to lipid peroxidation and organelle stress. In addition, experimental rat liver tissues have shown massive vacuolization associated with cellular swellings. Additionally, various signaling pathways, such as c-JNK N-terminal kinase (JNK), store-operated calcium entry, nuclear erythroid 2-related factor 2 (Nrf2), and protein kinase B/mammalian target of rapamycin (Akt/mTOR) pathways are stimulated by UA causing beneficial or harmful effects. Nevertheless, there are controversial issues, such as UA-induced inflammatory or anti-inflammatory responses, cytochrome P450 detoxifying UA into non-toxic or transforming UA into reactive metabolites, and unknown mechanism of the formation of vacuolization and membrane pore. This article focused on the previous and latest comprehensive putative mechanistic findings of UA-induced hepatotoxicity and cell death. New insights on controversial issues and future perspectives are also discussed and summarized.

Impact of Local Alloimmunity and Recipient Cells in Transplant Arteriosclerosis

RATIONALE

Transplant arteriosclerosis is the major limitation to long-term survival of solid organ transplantation. Although both immune and nonimmune cells have been suggested to contribute to this process, the complex cellular heterogeneity within the grafts, and the underlying mechanisms regulating the disease progression remain largely uncharacterized.

OBJECTIVE

We aimed to delineate the cellular heterogeneity within the allografts, and to explore possible mechanisms underlying this process.

METHODS AND RESULTS

Here, we reported the transcriptional profiling of 11 868 cells in a mouse model of transplant arteriosclerosis by single-cell RNA sequencing. Unbiased clustering analyses identified 21 cell clusters at different stages of diseases, and focused analysis revealed several previously unknown subpopulations enriched in the allografts. Interestingly, we found evidence of the local formation of tertiary lymphoid tissues and suggested a possible local modulation of alloimmune responses within the grafts. Intercellular communication analyses uncovered a potential role of several ligands and receptors, including Ccl21a and Cxcr3, in regulating lymphatic endothelial cell-induced early chemotaxis and infiltration of immune cells. In vivo mouse experiments confirmed the therapeutic potential of CCL21 and CXCR3 neutralizing antibodies in transplant arteriosclerosis. Combinational use of genetic lineage tracing and single-cell techniques further indicate the infiltration of host-derived c-Kit⁺ stem cells as heterogeneous populations in the allografts. Finally, we compared the immune response between mouse allograft and atherosclerosis models in single-cell RNA-seq analysis. By analyzing susceptibility genes of disease traits, we also identified several cell clusters expressing genes associated with disease risk.

CONCLUSIONS

Our study provides a transcriptional and cellular landscape of transplant arteriosclerosis, which could be fundamental to understanding the initiation and progression of this disease. CCL21/CXCR3 was also identified as important regulators of immune response and may serve as potential therapeutic targets in disease treatment.

Induction of programmed necrosis: A novel anti-cancer strategy for natural compounds

Cell death plays a critical role in organism development and the pathogenesis of diseases. Necrosis is considered a non-programmed cell death in an extreme environment. Recent advances have provided solid evidence that necrosis could be programmed and quite a few types of programmed necrosis, such as necroptosis, ferroptosis, pyroptosis, paraptosis, mitochondrial permeability transition-driven necrosis, and oncosis, have been identified. The specific biomarkers, detailed signaling, and precise pathophysiological importance of programmed necrosis are yet to be clarified, but these forms of necrosis provide novel strategies for the treatment of various diseases, including cancer. Natural compounds are a unique source of lead compounds for the discovery of anti-cancer drugs. Natural compounds can induce both apoptosis and programmed necrosis. In this review, we summarized the recent progress of programmed necrosis and introduced their natural inducers. Noptosis, which is a novel type of programmed necrosis that is strictly dependent on NAD(P)H: quinone oxidoreductase 1-derived oxidative stress was proposed. Furthermore, the anti-cancer strategies that take advantage of programmed necrosis and the main concerns from the scientific community in this regard were discussed.

An anticancer Os(II) bathophenanthroline complex as a human breast cancer stem cell-selective, mammosphere potent agent that kills cells by necroptosis

Conventional chemotherapy is mostly effective in the treatment of rapidly-dividing differentiated tumor cells but has limited application toward eliminating cancer stem cell (CSC) population. The presence of a very small number of CSCs may contribute to the development of therapeutic resistance, metastases, and relapse. Thus, treatment failure by developing novel anticancer drugs capable of effective targeting of CSCs is at present a major challenge for research focused on chemotherapy of cancer. Here, we show that Os(II) complex 2 [Os(η⁶-pcym)(bphen)(dca)]PF₆ (pcym = p-cymene, bphen = bathophenanthroline, and dca = dichloroacetate), is capable of efficient and selective killing CSCs in heterogeneous populations of human breast cancer cells MCF-7 and SKBR-3. Notably, its remarkable submicromolar potency to kill CSCs is considerably higher than that of its Ru analog, [Ru(η⁶-pcym)(bphen)(dca)]PF₆ (complex 1) and salinomycin, one of the most selective CSC-targeting compounds hitherto identified. Furthermore, Os(II) complex 2 reduces the formation, size, and viability of three-dimensional mammospheres which more closely reflect the tumor microenvironment than cells in traditional two-dimensional cultures. The antiproliferation studies and propidium iodide staining using flow cytometry suggest that Os(II) complex 2 induces human breast cancer stem cell death predominantly by necroptosis, a programmed form of necrosis. The results of this study demonstrate the promise of Os(II) complex 2 in treating human breast tumors. They also represent the foundation for further preclinical and clinical studies and applications of Os(II) complex 2 to comply with the emergent need for human breast CSCs-specific chemotherapeutics capable to treat chemotherapy-resistant and relapsed human breast tumors.

Amniotic cells share clusters of differentiation of fibroblasts and keratinocytes, influencing their ability to proliferate and aid in wound healing while impairing their angiogenesis capability

An alternative to cultured skin cell grafts usage in burn treatment is the graft of allogenic stem cells. We verified whether amniotic stem cells are better than the present therapeutic standard: grafts of autologous keratinocytes and fibroblasts along with autologous adipose-derived stem cells, and whether amniotic stem cells can support the growth of autologous keratinocytes and fibroblasts in the culture. The study was performed on the material from 18 amnia. Skin cells were obtained from 3 patients. In order to assess the influence of stem cells on keratinocytes and fibroblasts, the following experiments were performed: impact on viability and cell cycle, wound healing capability, angiogenesis capability, influence on the proliferation speed and capability to differentiate into skin cells. We demonstrated that human amniotic membrane-derived mesenchymal stem cells (hAMMSCs) share amniotic proteins with skin cells. Amniotic stem cells may replace skin fibroblasts in grafts due to the close similarity in their surface antigens, with significantly larger proliferative potential and ability to stimulate wound healing. It was shown that adding amniotic cells to both keratinocytes and fibroblast cultures accelerates directional migration by ≥ 40%. We confirmed in this study the influence of amniotic cells on the proliferation and cell cycle of fibroblasts and keratinocytes. Amniotic stem cells can be successfully used not only as a first choice graft but also to replace 3T3 line cells, supporting the proliferation of the cells during the culturing, as well as a supplementary graft supporting an autologous graft of keratinocytes and fibroblasts.

Half-sandwich Os(ii) and Ru(ii) bathophenanthroline complexes: anticancer drug candidates with unusual potency and a cellular activity profile in highly invasive triple-negative breast cancer cells

There is an urgent need to discover new, selective compounds to add to the limited arsenal of chemotherapeutics displaying selective toxicity for aggressive triple-negative breast cancer (TNBC) cells. The effect of two, recently developed metal-based half-sandwich complexes [Os(η6-pcym)(bphen)(dca)]PF6 (Os-dca) and [Ru(η6-pcym)(bphen)(dca)]PF6 (Ru-dca) [pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene); bphen = 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline); dca = dichloroacetate] on triple-negative breast cancer cells MDA-MB-231 is reported. The complexes display selective toxicity in several tumor cells (at submicromolar concentrations), and a prominent effect is observed against highly progressive triple negative breast cancer MDA-MB-231 cells for Os-dca. The lower potency of Ru-dca in comparison with Os-dca is apparently connected with a relatively quick release of the dca ligand due to the hydrolysis of Ru-dca before this complex enters the cells. Remarkably, both Os-dca and Ru-dca reduce successfully metastasis-related properties of the triple-negative breast cancer cells such as migration, invasion, and re-adhesion. The anti-metastatic effects of Os-dca and Ru-dca are associated with their ability to suppress matrix metalloproteinase activity and/or production and reduce the expression of aquaporins. Further detailed mechanistic studies reveal that Os-dca reverses Warburg's effect and oncosis seems to be a prominent mode of cell death that predominates over apoptosis. As such, Os-dca can efficiently overcome the resistance of cancer cells to clinically-used apoptotic inducers cisplatin and carboplatin. The cytostatic and anti-metastatic properties of Os-dca in MDA-MB-231 provide a strong impetus for the development of new metal-based compounds to target hardly treatable human TNBC cells and displaying different modes of action compared to the antitumor metallodrugs in clinical use.

Sigma Receptors as Endoplasmic Reticulum Stress "Gatekeepers" and their Modulators as Emerging New Weapons in the Fight Against Cancer

Despite the interest aroused by sigma receptors (SRs) in the area of oncology, their role in tumor biology remains enigmatic. The predominant subcellular localization and main site of activity of SRs are the endoplasmic reticulum (ER). Current literature data, including recent findings on the sigma 2 receptor subtype (S2R) identity, suggest that SRs may play a role as ER stress gatekeepers. Although SR endogenous ligands are still unknown, a wide series of structurally unrelated compounds able to bind SRs have been identified. Currently, the identification of novel antiproliferative molecules acting via SR interaction is a challenging task for both academia and industry, as shown by the fact that novel anticancer drugs targeting SRs are in the preclinical-stage pipeline of pharmaceutical companies (i.e., Anavex Corp. and Accuronix). So far, no clinically available anticancer drugs targeting SRs are still available. The present review focuses literature advancements and provides a state-of-the-art overview of SRs, with emphasis on their involvement in cancer biology and on the role of SR modulators as anticancer agents. Findings from preclinical studies on novel anticancer drugs targeting SRs are presented in brief.

Oncosis-inducing cyclometalated iridium(iii) complexes

Oncosis is a non-apoptotic form of programmed cell death (PCD), which differs from apoptosis in both morphological changes and inner pathways, and might hold the key to defeating a major obstacle in cancer therapy - drug-resistance, which is often a result of the intrinsic apoptosis resistance of tumours. However, despite the fact that the term "oncosis" was coined and used much earlier than apoptosis, little effort has been made to discover new drugs which can initiate this form of cell death, in comparison to drugs inducing apoptosis or any other type of PCD. So herein, we present the synthesis of a series of mitochondria-targeting cyclometalated Ir(iii) complexes, which activated the oncosis-specific protein porimin and calpain in cisplatin-resistant cell line A549R, and determined their cytotoxicity against a wide range of drug-resistant cancer types. To the best of our knowledge, these complexes are the very first metallo-components to induce oncosis in drug-resistant cancer cells.

RNA expression profiling in sulfamethoxazole-treated patients with a range of in vitro lymphocyte cytotoxicity phenotypes

The lymphocyte toxicity assay (LTA) is a proposed surrogate marker of sulfonamide antibiotic hypersensitivity. In the LTA, peripheral blood mononuclear cells (PBMCs) undergo apoptosis more readily in hypersensitive versus tolerant patients when exposed to drug-hydroxylamine metabolites in vitro. The purpose of this study was to identify key gene transcripts associated with increased cytotoxicity from sulfamethoxazole-hydroxylamine in human PBMCs in the LTA. The LTA was performed on PBMCs of 10 patients hypersensitive to trimethoprim-sulfamethoxazole (HS) and 10 drug-tolerant controls (TOL), using two cytotoxicity assays: YO-PRO (n = 20) and MTT (n = 12). mRNA expression profiles of PBMCs, enriched for CD8+ T cells, were compared between HS and TOL patients. Transcript expression was interrogated for correlation with % cytotoxicity from YO-PRO and MTT assays. Correlated transcripts of interest were validated by qPCR. LTA results were not significantly different between HS and TOL patients, and no transcripts were found to be differentially expressed between the two groups. 96 transcripts were correlated with cytotoxicity by YO-PRO (r = ±.63-.75, FDR 0.188). Transcripts were selected for validation based on mechanistic plausibility and three were significantly over-expressed by qPCR in high cytotoxicity patients: multi-specific organic anion transporter C (ABCC5), mitoferrin-1 (SLC25A37), and Porimin (TMEM123). These data identify novel transcripts that could contribute to sulfonamide-hydroxylamine induced cytotoxicity. These include SLC25A37, encoding a mitochondrial iron transporter, ABCC5, encoding an arylamine drug transporter, and TMEM123, encoding a transmembrane protein that mediates cell death.

Transcriptional profiling of liver in riboflavin-deficient chicken embryos explains impaired lipid utilization, energy depletion, massive hemorrhaging, and delayed feathering

BACKGROUND

A strain of Leghorn chickens (rd/rd), unable to produce a functional riboflavin-binding protein, lays riboflavin-deficient eggs, in which all embryos suddenly die at mid-incubation (days 13-15). This malady, caused by riboflavin deficiency, leads to excessive lipid accumulation in liver, impaired β-oxidation of lipid, and severe hypoglycemia prior to death. We have used high-density chicken microarrays for time-course transcriptional scans of liver in chicken embryos between days 9-15 during this riboflavin-deficiency-induced metabolic catastrophe. For comparison, half of rd/rd embryos (n = 16) were rescued from this calamity by injection of riboflavin just prior to incubation of fertile eggs from rd/rd hens.

RESULTS

No significant differences were found between hepatic transcriptomes of riboflavin-deficient and riboflavin-rescued embryos at the first two ages (days 9 and 11). Overall, we found a 3.2-fold increase in the number of differentially expressed hepatic genes between day 13 (231 genes) and day 15 (734 genes). Higher expression of genes encoding the chicken flavoproteome was more evident in rescued- (15 genes) than in deficient-embryos (4 genes) at day 15. Diminished activity of flavin-dependent enzymes in riboflavin-deficient embryos blocks catabolism of yolk lipids, which normally serves as the predominant source of energy required for embryonic development.

CONCLUSIONS

Riboflavin deficiency in mid-stage embryos leads to reduced expression of numerous genes controlling critical functions, including β-oxidation of lipids, blood coagulation and feathering. Surprisingly, reduced expression of feather keratin 1 was found in liver of riboflavin-deficient embryos at e15, which could be related to their delayed feathering and sparse clubbed down. A large number of genes are expressed at higher levels in liver of riboflavin-deficient embryos; these up-regulated genes control lipid storage/transport, gluconeogenesis, ketogenesis, protein catabolism/ubiquitination and cell death.

Detergent sclerosants at sub-lytic concentrations induce endothelial cell apoptosis through a caspase dependent pathway

To investigate the apoptotic effects of detergent sclerosants sodium tetradecylsulphate (STS) and polidocanol (POL) on endothelial cells at sub-lytic concentrations. Human umbilical vein endothelial cells (HUVECs) were isolated and labelled with antibodies to assess for apoptosis and examined with confocal microscopy and flow cytometry. Isolated HUVECs viability was assessed using propidium iodide staining. Early apoptosis was determined by increased phosphatidylserine exposure by lactadherin binding. Caspase 3, 8, 9 and Bax activation as well as inhibitory assays with Pan Caspase (Z-VAD-FMK) and Bax (BI-6C9) were assessed to identify apoptotic pathways. Porimin activation was used to assess cell membrane permeability. Cell lysis reached almost 100 % with STS at 0.3 % and with POL at 0.6 %. Apoptosis was seen with both STS and POL at concentrations ranging from 0.075 to 0.15 %. PS exposure increased with both STS and POL and exhibited a dose-dependent trend. Active Caspase 3, 8 and 9 but not Bax were increased in HUVECs stimulated with low concentrations of both STS and POL. Inhibitory assays demonstrated Caspase 3, 8, 9 inhibition at low concentrations (0.075 to 0.6 %) with both STS and POL. Both agents increased the activation of porimin at all concentrations. Both sclerosants induced endothelial cell (EC) apoptosis at sub-lytic concentrations through a caspase-dependant pathway. Both agents induced EC oncosis.

Genome-Wide Profiling Reveals That Herbal Medicine Jinfukang-Induced Polyadenylation Alteration Is Involved in Anti-Lung Cancer Activity

Alternative polyadenylation (APA) plays an important role in regulation of genes expression and is involved in many biological processes. As eukaryotic cells receive a variety of external signals, genes produce diverse transcriptional isoforms and exhibit different translation efficiency. The traditional Chinese medicine (TCM) Jinfukang (JFK) has been effectively used for lung cancer treatment. In this study, we investigated whether JFK exerts its antitumor effect by modulating APA patterns in lung cancer cells. We performed a genome-wide APA site profiling analysis in JFK treated lung cancer cells A549 with 3T-seq approach that we reported previously. Comparing with those in untreated A549, in JFK treated A549 we observed APA-mediated 3′ UTRs alterations in 310 genes including 77 genes with shortened 3′ UTRs. In particular, we identified TMEM123, a gene involved in oncotic cell death, which produced transcripts with shortened 3′ UTR and thus was upregulated upon JFK treatment. Taken together, our studies suggest that APA might be one of the antitumor mechanisms of JFK and provide a new insight for the understanding of TCM against cancer.

Anticancer potential of sanguinarine for various human malignancies

Sanguinarine (Sang) - a benzophenanthridine alkaloid extracted from Sanguinaria canadensis - exhibits antioxidant, anti-inflammatory, proapoptotic and growth inhibitory activities on tumor cells of various cancer types as established by in vivo and in vitro studies. Although the underlying mechanism of Sang antitumor activity is yet to be fully elucidated, Sang has displayed multiple biological effects, which remain to suggest its possible use in plant-derived treatments of human malignancies. This review covers the anticancer abilities of Sang including inhibition of aberrantly activated signal transduction pathways, induction of cell death and inhibition of cancer cell proliferation. It also highlights Sang-mediated inhibition of angiogenesis, inducing the expression of tumor suppressors, sensitization of cancer cells to standard chemotherapeutics to enhance their cytotoxic effects, while addressing the present need for further pharmacokinetic-based studies.

Expression of pre-selected TMEMs with predicted ER localization as potential classifiers of ccRCC tumors

Background

VHL inactivation is the most established molecular characteristic of clear cell renal cell carcinoma (ccRCC), with only a few additional genes implicated in development of this kidney tumor. In recently published ccRCC gene expression meta-analysis study we identified a number of deregulated genes with limited information available concerning their biological role, represented by gene transcripts belonging to transmembrane proteins family (TMEMs). TMEMs are predicted to be components of cellular membranes, such as mitochondrial membranes, ER, lysosomes and Golgi apparatus. Interestingly, the function of majority of TMEMs remains unclear. Here, we analyzed expression of ten TMEM genes in the context of ccRCC progression and development, and characterized these proteins bioinformatically.

Methods

The expression of ten TMEMs (RTP3, SLC35G2, TMEM30B, TMEM45A, TMEM45B, TMEM61, TMEM72, TMEM116, TMEM207 and TMEM213) was measured by qPCR. T-test, Pearson correlation, univariate and multivariate logistic and Cox regression were used in statistical analysis. The topology of studied proteins was predicted with Metaserver, together with PSORTII, Pfam and Localizome tools.

Results

We observed significant deregulation of expression of 10 analyzed TMEMs in ccRCC tumors. Cluster analysis of expression data suggested the down-regulation of all tested TMEMs to be a descriptor of the most advanced tumors. Logistic and Cox regression potentially linked TMEM expression to clinical parameters such as: metastasis, Fuhrman grade and overall survival. Topology predictions classified majority of analyzed TMEMs as type 3 and type 1 transmembrane proteins, with predicted localization mainly in ER.

Conclusions

The massive down-regulation of expression of TMEM family members suggests their importance in the pathogenesis of ccRCC and the bioinformatic analysis of TMEM topology implies a significant involvement of ER proteins in ccRCC pathology.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1530-4) contains supplementary material, which is available to authorized users.

Design of magnetic nanoparticles for hepatocellular carcinoma treatment using the control mechanisms of the cell internal nucleus and external membrane

Nanoparticle drugs and relevant treatment technologies have achieved widespread attention in recent years. Hepatocellular carcinoma (HCC) remains a challenging malignancy of worldwide importance since it is one of the worst malignant tumors. In this study, magnetic Fe₃O₄ nanoparticles are prepared via a co-precipitation reaction with self-assembled surface monolayers of oleic acid molecules. For synthesizing the nanoparticle anti-tumor drug used against HCC, the liquid photo-immobilization method is used to bond the photoactive N-isopropylacrylamide derivative (NIPAm-AA) onto the oleic acid monolayer for subsequently embedding doxorubicin, photoactive tumor necrosis factor-α (TNF-α)/interferon-γ (IFN-γ), and folic acid (FOL). We investigate how the nanoparticle drug inhibits the growth of human hepatocellular carcinoma HepG2 cells in vitro and in vivo. Remarkably, our characterizations show that the nanoparticle drug demonstrates much higher anticancer efficacy (94.7%) in vitro than previously reported drugs. It is revealed that the programmed cell death induced by the drug is mainly oncosis, a new programmed cell death pathway, different from earlier proposed mechanisms. This oncosis mechanism is also confirmed in the other two hepatocellular carcinoma cells (BEL-7402 and Huh-7). This study may be helpful for developing a new type of nanoparticle drug capable of assuring molecular control of both the cell inner nucleus and outer membrane as a means to enormously increase the drug efficacy in human hepatocellular carcinoma.

Neuronal cell death: an overview of its different forms in central and peripheral neurons

The discovery of neuronal cell death dates back to the nineteenth century. Nowadays, after a very long period of conceptual difficulties, the notion that cell death is a phenomenon occurring during the entire life course of the nervous system, from neurogenesis to adulthood and senescence, is fully established. The dichotomy between apoptosis, as the prototype of programmed cell death (PCD ), and necrosis, as the prototype of death caused by an external insult, must be carefully reconsidered, as different types of PCD: apoptosis, autophagy, pyroptosis, and oncosis have all been demonstrated in neurons (and glia ). These modes of PCD may be triggered by different stimuli, but share some intracellular pathways such that different types of cell death may affect the same population of neurons according to several intrinsic and extrinsic factors. Therefore, a mixed morphology is often observed also depending on degrees of differentiation, activity, and injury. The main histological and ultrastructural features of the different types of cell death in neurons are described and related to the cellular pathways that are specifically activated in any of these types of PCD.

Sevoflurane post-conditioning protects isolated rat hearts against ischemia-reperfusion injury via activation of the ERK1/2 pathway

AIM

To investigate the role of extracellular signal-regulated kinases (ERKs) in sevoflurane post-conditioning induced cardioprotection in vitro.

METHODS

Isolated rat hearts were subjected to 30 min ischemia followed by 120 min reperfusion (I/R). Sevoflurane post-conditioning was carried out by administration of O2-enriched gas mixture with 3% sevoflurane (SEVO) for 15 min from the onset of reperfusion. Cardiac functions, myocardial infarct size, myocardial ATP and NAD(+) contents, mitochondrial ultrastructure, and anti-apototic and anti-oncosis protein levels were measured.

RESULTS

Sevoflurane post-conditioning significantly improved the heart function, decreased infarct size and mitochondria damage, and increased myocardial ATP and NAD(+) content in the I/R hearts. Furthermore, sevoflurane post-conditioning significantly increased the levels of p-ERK and p-p70S6K, decreased the levels of porimin, caspase-8, cleaved caspase-3, and cytosolic cytochrome c in the I/R hearts. Co-administration of the ERK1/2 inhibitor PD98059 (20 μmol/L) abolished the sevoflurane-induced protective effects against myocardial I/R.

CONCLUSION

Sevoflurane post-conditioning protects isolated rat hearts against myocardial I/R injury and inhibits cell oncosis and apoptosis via activation of the ERK1/2 pathway.

Complex network-driven view of genomic mechanisms underlying Parkinson's disease: analyses in dorsal motor vagal nucleus, locus coeruleus, and substantia nigra

Parkinson's disease (PD)—classically characterized by severe loss of dopaminergic neurons in the substantia nigra pars compacta—has a caudal-rostral progression, beginning in the dorsal motor vagal nucleus and, in a less extent, in the olfactory system, progressing to the midbrain and eventually to the basal forebrain and the neocortex. About 90% of the cases are idiopathic. To study the molecular mechanisms involved in idiopathic PD we conducted a comparative study of transcriptional interaction networks in the dorsal motor vagal nucleus (VA), locus coeruleus (LC), and substantia nigra (SN) of idiopathic PD in Braak stages 4-5 (PD) and disease-free controls (CT) using postmortem samples. Gene coexpression networks (GCNs) for each brain region (patients and controls) were obtained to identify highly connected relevant genes (hubs) and densely interconnected gene sets (modules). GCN analyses showed differences in topology and module composition between CT and PD networks for each anatomic region. In CT networks, VA, LC, and SN hub modules are predominantly associated with neuroprotection and homeostasis in the ageing brain, whereas in the patient's group, for the three brain regions, hub modules are mostly related to stress response and neuron survival/degeneration mechanisms.

Cell death pathways in astrocytes with a modified model of oxygen-glucose deprivation

Traditional oxygen-glucose deprivation (OGD) models do not produce sufficiently stable and continuous deprivation to induce cell death in the ischemic core. Therefore, we modified the OGD model to mimic the observed damage in the ischemic core following stroke and utilized this new model to study cell death pathways in astrocytes. The PO₂ and pH levels in the astrocyte culture medium were compared between a physical OGD group, a chemical OGD group and a mixed OGD group. The mixed OGD group was able to maintain anaerobic conditions in astrocyte culture medium for 6 h, while the physical and the chemical groups failed to maintain such conditions. Astrocyte viability decreased and LDH release into in the medium increased as a function of exposure to OGD. Compared to the control group, the expression of active caspase-3 in the mixed OGD group increased within 2 h after OGD, but decreased after 2 h of OGD. Additionally, porimin mRNA levels did not significantly increase during the first 2 h of OGD, while bcl-2 mRNA levels decreased at 1 h. However, both porimin and bcl-2 mRNA levels increased after 2 h of OGD; interestingly, they both suddenly decreased at 4 h of OGD. Taken together, these results indicate that apoptosis and oncosis are the two cell death pathways responsible for astrocyte death in the ischemic core. However, the main death pathway varies depending on the OGD period.

Oncosis: an important non-apoptotic mode of cell death

It is now increasingly accepted that apoptosis may not be the only form of cell death seen in vitro and in vivo; hence there is a need to study novel forms of cell death. The explosion of cell death research that followed the recognition of apoptosis by Kerr and colleagues in the late 1960s completely obscured the fact that apoptosis is not the only form of cell death. Apoptosis manifests itself by cell shrinkage followed by breakup; another form (oncosis) is almost the opposite: it involves cell swelling and coagulation of the cytoplasm. The name oncosis was chosen over a century ago by von Recklinghausen, a top collaborator of Rudolph Virchow and thereby one of the founders of cellular pathology. Nevertheless, oncosis was forgotten, largely because a satisfactory technique for preparing tissue sections did not exist at the time. Also confusion developed regarding the distinction between oncosis as a mode of cell injury and cell death, and necrosis as a degradation process following cell death. In this review we have described the many characteristics of oncosis from a morphological and biochemical standpoint, and we briefly examine the application of oncosis in disease processes.

A model for cardiomyocyte cell death: insights into mechanisms of oncosis

It is now known that there are at least two basic patterns of cell injury progressing to cell death: cell injury with swelling, known as oncosis, and cell injury with shrinkage, known as apoptosis. Both types of cell death are "programmed" in the sense that the genetic information and many of the enzymes and other factors pre-exist in the cell. Previous investigation has pointed to cardiomyocyte ischemic injury evolving as the oncotic pattern of injury, although apoptosis has also been implicated. This study was designed, using a unique cell model system, to gain insight into the molecular events of anticancer agent-induced cardiomyocyte injury. Cardiomyocytes exposed for 2 h to 1.5 μg/ml sanguinarine consistently displayed the morphology of apoptosis in over 80% of cells, whereas a higher dose of 25 μg/ml at 2 h yielded the pattern of oncosis in over 90% of cells. Microarray analysis revealed altered expression of 2514 probes in sanguinarine-induced oncosis and 1643 probes in apoptosis at a level of significance of p<0.001. Some of the inductions such as perforin were found to be higher than 11-fold in oncosis. When perforin was blocked by perforin-specific siRNA we found a reduction in oncotic cell death. These results strengthen the notion that oncosis is not representative of nonspecific necrosis, but constitutes a genetically controlled form of "programmed cell death"; and also that oncosis might represent a pathogenetic mechanism of cardiomyocyte injury. This is also the first demonstration of the involvement of perforin in cardiomyocyte oncosis.

Lonely killers: effector cell- and complement-independent non-proapoptotic cytotoxic antibodies inducing membrane lesions

The majority of the most effective monoclonal antibodies (mAbs) currently in the clinics bind to cancer or immune cells. Classic mechanisms of cell killing by therapeutic mAbs include antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity and induction of apoptosis by engagement of specific cell ligands. A few reports have described mAbs whose cytotoxic activity is Fc-independent and that do not induce the morphological and biochemical changes associated with the apoptosis-type of cell death. Even fewer works describe mAbs able to directly induce membrane lesions. Here, we discuss the available data on those molecules and their cell killing activity, with particular attention to the case of a mAb specific for the tumor-associated N-glycolyl (Neu5Gc)-GM3 ganglioside (GM3(Neu5Gc)). Some similarities are found in the cell death pathways triggered by these mAbs, but data are not abundant. We conclude that the usefulness of mAbs with a direct cytotoxic activity for immunotherapeutic strategies deserves deeper research.

Intraclonal complexity in chronic lymphocytic leukemia: fractions enriched in recently born/divided and older/quiescent cells

The failure of chemotherapeutic regimens to eradicate cancers often results from the outgrowth of minor subclones with more dangerous genomic abnormalities or with self-renewing capacity. To explore such intratumor complexities in B-cell chronic lymphocytic leukemia (CLL), we measured B-cell kinetics in vivo by quantifying deuterium ((2)H)-labeled cells as an indicator of a cell that had divided. Separating CLL clones on the basis of reciprocal densities of chemokine (C-X-C motif) receptor 4 (CXCR4) and cluster designation 5 (CD5) revealed that the CXCR4(dim)CD5(bright) (proliferative) fraction contained more (2)H-labeled DNA and hence divided cells than the CXCR4(bright)CD5(dim) (resting) fraction. This enrichment was confirmed by the relative expression of two cell cycle-associated molecules in the same fractions, Ki-67 and minichromosome maintenance protein 6 (MCM6). Comparisons of global gene expression between the CXCR4(dim)CD5(bright) and CXCR4(bright)CD5(dim) fractions indicated higher levels of pro-proliferation and antiapoptotic genes and genes involved in oxidative injury in the proliferative fraction. An extended immunophenotype was also defined, providing a wider range of surface molecules characteristic of each fraction. These intraclonal analyses suggest a model of CLL cell biology in which the leukemic clone contains a spectrum of cells from the proliferative fraction, enriched in recently divided robust cells that are lymphoid tissue emigrants, to the resting fraction enriched in older, less vital cells that need to immigrate to lymphoid tissue or die. The model also suggests several targets preferentially expressed in the two populations amenable for therapeutic attack. Finally, the study lays the groundwork for future analyses that might provide a more robust understanding of the development and clonal evolution of this currently incurable disease.

Anti-NeuGcGM3 antibodies, actively elicited by idiotypic vaccination in nonsmall cell lung cancer patients, induce tumor cell death by an oncosis-like mechanism

1E10 is a murine anti-idiotypic mAb specific for an idiotypic mAb that reacts with NeuGc-containing gangliosides, sulfatides, and Ags expressed in some human tumors. In melanoma, breast, and lung cancer patients, this anti-idiotypic Ab was able to induce a specific Ab response against N-glycosylated gangliosides, attractive targets for cancer immunotherapy as these glycolipids are not naturally expressed in humans. A clinical study with nonsmall cell lung cancer patients showed encouraging clinical benefits. Immunological studies performed in 20 of these patients suggested a correlation between the induction of Abs against NeuGcGM3 and longer survival times. The induced anti-NeuGcGM3 Abs recognized and directly killed tumor cells expressing the Ag, by a mechanism independent of complement activation. In the present work, we show that this cytotoxicity differs from apoptosis because it is temperature independent, no chromatin condensation or caspase 3 induction are detected, and the DNA fragmentation induced has a different pattern than the one characteristic for apoptosis. It is a very quick process and involves cytosqeleton reorganization. The Abs induce cellular swelling and the formation of big membrane lesions that allow the leakage of cytoplasm and the loss of the cell membrane integrity. All of these characteristics resemble a process of oncotic necrosis. To our knowledge, this is the first report of the active induction in cancer patients of NeuGcGM3-specific Abs able to induce complement independent oncotic necrosis to tumor cells. These results contribute to reinforcing the therapeutic potential of anti-idiotypic vaccines and the importance of NeuGcGM3 ganglioside as antitumor target.

Differential gene expression analysis identifies murine Cacnb3 as strongly upregulated in distinct dendritic cell populations upon stimulation

Langerhans cells (LCs) represent the dendritic cell (DC) population in the epidermis. Among the set of genes induced in primary mouse LCs in response to stimulation, both isoforms of the voltage-dependent Ca²(+) channel (VDCC) regulatory subunit Cacnb3 as well as the DC maturation marker Fscn1 were upregulated most strongly. Comparable results were obtained for a recently described myeloid DC line (SP37A3). Other antigen presenting cell populations, namely, bone marrow-derived DCs, macrophages and primary B cells, showed no stimulation-associated upregulation of Cacnb3 expression. Pharmacological inhibition of Ca²(+) channel activity during the stimulation of SP37A3 cells enhanced their T cell stimulatory capacity, while selective inhibition of L-type VDCC had no effect. Both Cacnb3 isoforms, similar to Fscn1, required JNK and p38 kinase activity for stimulation-associated upregulation, and this process was inhibited by ERK and PI(3)K. The putative promoter region of Cacnb3 isoform 2, which we found to be less ubiquitously expressed than Cacnb3 isoform 1, exerted reporter activity in LC-like cell lines. Our findings suggest that Cacnb3 exerts its function in distinct activated DC populations. Further analysis of the regulatory region(s) facilitating stimulation-induced upregulation of Cacnb3 expression in these DC subsets will help to gain better insight into DC subset specific gene regulation.

Identification of a novel marker for dendritic cell maturation, mouse transmembrane protein 123

Dendritic cells (DCs) are a group of professional antigen-presenting cells, and many genes are known to be associated with their maturation. We compared the transcriptional profiles of immature and mature mouse Langerhans cells using the suppressive, subtractive hybridization method and identified a novel gene of unknown function, termed herein transmembrane protein 123 (Tmem123), of which mRNA expression was enhanced in mature but not in immature Langerhans cells. Its expression was also enhanced in other mature DCs such as bone marrow-derived DCs (BMDCs) and splenic DCs. Interestingly, CD40 expression was up-regulated on mature BMDCs cultured with colchicine concurrently with the enhanced expression of Tmem123 compared with that of fresh BMDCs. Furthermore, the expression of CD40 was enhanced on Tmem123-transfected DC2.4 cells, a mouse BMDC-derived cell line, compared with that on mock-transfected DC2.4 cells. This enhancement of CD40 expression did not occur after deletion of lysosome/endosome targeting YXXϕ motifs (where X is any amino acid and ϕ is a bulky hydrophobic amino acid) in the Tmem123 cytoplasmic tail. By stimulation with anti-CD40 monoclonal antibody, these transfectants secreted an increased amount of IL-12/23 p40 compared with mock-transfected DC2.4 cells. Thus, our study demonstrates that Tmem123 may be used as a new maturation marker in DCs and that this molecule may be closely associated with the cell surface expression of CD40.

Selection against undifferentiated human embryonic stem cells by a cytotoxic antibody recognizing podocalyxin-like protein-1

Future therapeutic applications of differentiated human embryonic stem cells (hESC) carry a risk of teratoma formation by contaminating undifferentiated hESC. We generated 10 monoclonal antibodies (mAbs) against surface antigens of undifferentiated hESC, showing strong reactivity against undifferentiated, but not differentiated hESC. The mAbs did not cross react with mouse fibroblasts and showed weak to no reactivity against human embryonal carcinoma cells. Notably, one antibody (mAb 84) is cytotoxic to undifferentiated hESC and NCCIT cells in a concentration-dependent, complement-independent manner. mAb 84 induced cell death of undifferentiated, but not differentiated hESC within 30 minutes of incubation, and immunoprecipitation of the mAb-antigen complex revealed that the antigen is podocalyxin-like protein-1. Importantly, we observed absence of tumor formation when hESC and NCCIT cells were treated with mAb 84 prior to transplantation into severe combined immunodeficiency mice. Our data indicate that mAb 84 may be useful in eliminating residual hESC from differentiated cells populations for clinical applications. Disclosure of potential conflicts of interest is found at the end of this article.

Molecular mechanisms of primary and secondary mucosal immunity using avian infectious bronchitis virus as a model system

Although mucosal immune responses are critical for protection of hosts from clinical illness and even mortality caused by mucosal pathogens, the molecular mechanism of mucosal immunity, which is independent of systemic immunity, remains elusive. To explore the mechanistic basis of mucosal protective immunity, gene transcriptional profiling in mucosal tissues was evaluated after the primary and secondary immunization of animals with an attenuated avian infectious bronchitis virus (IBV), a prototype of Coronavirus and a well-characterized mucosal pathogen. Results showed that a number of innate immune factors including toll-like receptors (TLRs), retinoic-acid-inducible gene-1 (RIG-1), type I interferons (IFNs), complements, and interleukin-1 beta (IL-1β) were activated locally after the primary immunization. This was accompanied or immediately followed by a potent Th1 adaptive immunity as evidenced by the activation of T-cell signaling molecules, surface markers, and effector molecules. A strong humoral immune response as supported by the significantly up-regulated immunoglobulin (Ig) gamma chain was observed in the absence of innate, Th1 adaptive immunity, or IgA up-regulation after the secondary immunization, indicating that the local memory response is dominated by IgG. Overall, the results provided the first detailed kinetics on the molecular basis underlying the development of primary and secondary mucosal immunity. The key molecular signatures identified may provide new opportunities for improved prophylactic and therapeutic strategies to combat mucosal infections.