Highly Selective Anti-Cancer Activity of Cholesterol-Interacting Agents Methyl-β-Cyclodextrin and Ostreolysin A/Pleurotolysin B Protein Complex on Urothelial Cancer Cells

Acyl-coenzyme A: cholesterol acyltransferase inhibitor avasimibe suppresses tumorigenesis and induces G1-phase cell-cycle arrest by activating PPARγ signaling pathway in bladder cancer

Reprogramming of energy metabolism is one of the most important characteristics of tumors. Bladder cancer (BLCA) cells contain higher levels of cholesterol content compared to normal cells, and acyl-coenzyme A (CoA): cholesterol acyltransferase-1 (ACAT1) plays a crucial role in the esterification of cholesterol. Avasimibe is a drug that has been used in the treatment of atherosclerosis, and it can effectively inhibit ACAT1. We observed that ACAT1 was significantly up-regulated in BLCA and positively correlated with tumor grade. By avasimibe administration, the proliferation and migration ability of BLCA cells were reduced, while the production of ROS was strongly increased, accompanied by the up-regulated expression of ROS metabolism-related proteins SOD2 and catalase. Furthermore, BLCA cell cycle was arrested at the G1 phase, accompanied by the downregulation of cell cycle-related proteins (CCNA1/2, CCND1, CDK2 and CDK4), while the PPARγ was found to be up-regulated at both transcriptional and protein levels after avasimibe treatment. Then we found that the PPARγ antagonist GW9662 could reverse the effect of avasimibe on the cell cycle. Moreover, xenograft and pulmonary metastasis models further demonstrated that avasimibe could inhibit tumor cell growth and metastasis in vivo. Taken together, our results for the first time revealed that avasimibe can inhibit BLCA progression and metastasis, and PPARγ signaling pathway may play a key role in regulation of cell cycle distribution induced by avasimibe.

Targeting cholesterol metabolism in Cancer: From molecular mechanisms to therapeutic implications

Cholesterol is an essential component of cell membranes and helps to maintain their structure and function. Abnormal cholesterol metabolism has been linked to the development and progression of tumors. Changes in cholesterol metabolism triggered by internal or external stimuli can promote tumor growth. During metastasis, tumor cells require large amounts of cholesterol to support their growth and colonization of new organs. Recent research has shown that cholesterol metabolism is reprogrammed during tumor development, and this can also affect the anti-tumor activity of immune cells in the surrounding environment. However, identifying the specific targets in cholesterol metabolism that regulate cancer progression and the tumor microenvironment is still a challenge. Additionally, exploring the potential of combining statin drugs with other therapies for different types of cancer could be a worthwhile avenue for future drug development. In this review, we focus on the molecular mechanisms of cholesterol and its derivatives in cell metabolism and the tumor microenvironment, and discuss specific targets and relevant therapeutic agents that inhibit aspects of cholesterol homeostasis.

A single point mutation expands the applicability of ostreolysin A6 in biomedicine

An aegerolysin protein ostreolysin A6 (OlyA6) binds to cholesterol-complexed sphingomyelin and can be used for specific labelling of lipid rafts. In addition, OlyA6 interacts with even higher affinity with ceramide phosphoethanolamine (CPE), a sphingolipid that dominates in invertebrate cell membranes. In the presence of pleurotolysin B, a protein bearing the membrane-attack complex/perforin domain, OlyA6 forms pores in insect midgut cell membranes and acts as a potent bioinsecticide. It has been shown that a point mutation of glutamate 69 to alanine (E69A) allows OlyA6 to bind to cholesterol-free sphingomyelin. Using artificial lipid membranes and mammalian MDCK cells, we show that this mutation significantly enhances the interaction of OlyA6 with sphingomyelin and CPE, and allows recognition of these sphingolipids even in the absence of cholesterol. Our results suggest that OlyA6 mutant E69A could serve as complementary tool to detect and study cholesterol-associated and free sphingomyelin or CPE in membranes. However, the mutation does not improve the membrane-permeabilizing activity after addition of pleurotolysin B, which was confirmed in toxicity tests on insect and mammalian cell lines, and on Colorado potato beetle larvae.

Molecular, morphological and functional properties of tunnelling nanotubes between normal and cancer urothelial cells: New insights from the in vitro model mimicking the situation after surgical removal of the urothelial tumor

Tunnelling nanotubes (TNTs) are membranous connections that represent a unique type of intercellular communication in different cell types. They are associated with cell physiology and cancer pathology. The possible existence of tunnelling nanotubes communication between urothelial cancer and normal cells has not yet been elucidated. Therefore, we analyzed TNTs formed by T24 cells (human invasive cancer urothelial cells) and normal porcine urothelial (NPU) cells, which serve as surrogate models for healthy human urothelial cells. Monocultures and cocultures of NPU and T24 cells were established and analyzed using live-cell imaging, optical tweezers, fluorescence microscopy, and scanning electron microscopy. TNTs of NPU cells differed significantly from tunnelling nanotubes of T24 cells in number, length, diameter, lipid composition, and elastic properties. Membrane domains enriched in cholesterol/sphingomyelin were present in tunnelling nanotubes of T24 cells but not in NPU cells. The tunnelling nanotubes in T24 cells were also easier to bend than the tunnelling nanotubes in NPU cells. The tunnelling nanotubes of both cell types were predominantly tricytoskeletal, and contained actin filaments, intermediate filaments, and microtubules, as well as the motor proteins myosin Va, dynein, and kinesin 5B. Mitochondria were transported within tunnelling nanotubes in living cells, and were colocalized with microtubules and the microtubule-associated protein dynamin 2. In cocultures, heterocellular tunnelling nanotubes were formed between NPU cells and T24 cells and vice versa. The presence of connexin 43 at the end of urothelial tunnelling nanotubes suggests a junctional connection and the involvement of tunnelling nanotube in signal transduction. In this study, we established a novel urothelial cancer-normal coculture model and showed cells in the minority tend to form tunnelling nanotubes with cells in the majority. The condition with cancer cells in the minority is an attractive model to mimic the situation after surgical resection with remaining cancer cells and may help to understand cancer progression and recurrence. Our results shed light on the biological activity of tunnelling nanotubes and have the potential to advance the search for anticancer drugs that target tunnelling nanotubes.

Towards Understanding the Function of Aegerolysins

Aegerolysins are remarkable proteins. They are distributed over the tree of life, being relatively widespread in bacteria and fungi, but also present in some insects, plants, protozoa, and viruses. Despite their abundance in cells of certain developmental stages and their presence in secretomes, only a few aegerolysins have been studied in detail. Their function, in particular, is intriguing. Here, we summarize previously published findings on the distribution, molecular interactions, and function of these versatile aegerolysins. They have very diverse protein sequences but a common fold. The machine learning approach of the AlphaFold2 algorithm, which incorporates physical and biological knowledge of protein structures and multisequence alignments, provides us new insights into the aegerolysins and their pore-forming partners, complemented by additional genomic support. We hypothesize that aegerolysins are involved in the mechanisms of competitive exclusion in the niche.

Purinergic receptors are a key bottleneck in tumor metabolic reprogramming: The prime suspect in cancer therapeutic resistance

ATP and other nucleoside phosphates have specific receptors named purinergic receptors. Purinergic receptors and ectonucleotidases regulate various signaling pathways that play a role in physiological and pathological processes. Extracellular ATP in the tumor microenvironment (TME) has a higher level than in normal tissues and plays a role in cancer cell growth, survival, angiogenesis, metastasis, and drug resistance. In this review, we investigated the role of purinergic receptors in the development of resistance to therapy through changes in tumor cell metabolism. When a cell transforms to neoplasia, its metabolic processes change. The metabolic reprogramming modified metabolic feature of the TME, that can cause impeding immune surveillance and promote cancer growth. The purinergic receptors contribute to therapy resistance by modifying cancer cells' glucose, lipid, and amino acid metabolism. Limiting the energy supply of cancer cells is one approach to overcoming resistance. Glycolysis inhibitors which reduce intracellular ATP levels may make cancer cells more susceptible to anti-cancer therapies. The loss of the P2X7R through glucose intolerance and decreased fatty acid metabolism reduces therapeutic resistance. Potential metabolic blockers that can be employed in combination with other therapies will aid in the discovery of new anti-cancer immunotherapy to overcome therapy resistance. Therefore, therapeutic interventions that are considered to inhibit cancer cell metabolism and purinergic receptors simultaneously can potentially reduce resistance to treatment.

Characterization and cytotoxic activity of ribotoxin-like proteins from the edible mushroom Pleurotus eryngii

Ribotoxin-like proteins (RL-Ps) represent a novel specific ribonuclease family found in edible mushrooms and are able to inhibit protein synthesis. Here, we report the characterization and cytotoxic effects of four novel RL-Ps, named eryngitins, isolated from fruiting bodies of the king oyster mushroom (Pleurotus eryngii). These proteins induced formation of α-fragment from rabbit ribosomes, characteristic of their enzymatic action. The two 15 kDa eryngitins (3 and 4) are considerably more thermostable than the 21 kDa ones (1 and 2), however their overall structural features, as determined by far-UV CD spectrometry, are similar. Complete in vitro digestibility by pepsin-trypsin, and lack of cytotoxicity towards human HUVEC cells suggest low toxicity of eryngitins, if ingested. However, eryngitins exhibit cytotoxic action against insect Sf9 cells, suggesting their possible use in biotechnological applications as bioinsecticides. This cytotoxicity was not enhanced in the presence of cytolytic protein complexes based on aegerolysin proteins from Pleurotus mushrooms.

The Golgi complex: An organelle that determines urothelial cell biology in health and disease

The Golgi complex undergoes considerable structural remodeling during differentiation of urothelial cells in vivo and in vitro. It is known that in a healthy bladder the differentiation from the basal to the superficial cell layer leads to the formation of the tightest barrier in our body, i.e., the blood–urine barrier. In this process, urothelial cells start expressing tight junctional proteins, apical membrane lipids, surface glycans, and integral membrane proteins, the uroplakins (UPs). The latter are the most abundant membrane proteins in the apical plasma membrane of differentiated superficial urothelial cells (UCs) and, in addition to well-developed tight junctions, contribute to the permeability barrier by their structural organization and by hindering endocytosis from the apical plasma membrane. By studying the transport of UPs, we were able to demonstrate their differentiation-dependent effect on the Golgi architecture. Although fragmentation of the Golgi complex is known to be associated with mitosis and apoptosis, we found that the process of Golgi fragmentation is required for delivery of certain specific urothelial differentiation cargoes to the plasma membrane as well as for cell–cell communication. In this review, we will discuss the currently known contribution of the Golgi complex to the formation of the blood–urine barrier in normal UCs and how it may be involved in the loss of the blood–urine barrier in cancer. Some open questions related to the Golgi complex in the urothelium will be highlighted.

Ceramide Aminoethylphosphonate as a New Molecular Target for Pore-Forming Aegerolysin-Based Protein Complexes

Ostreolysin A6 (OlyA6) is a 15 kDa protein produced by the oyster mushroom (Pleurotus ostreatus). It belongs to the aegerolysin family of proteins and binds with high affinity to the insect-specific membrane sphingolipid, ceramide phosphoethanolamine (CPE). In concert with its partnering protein with the membrane-attack-complex/perforin domain, pleurotolysin B (PlyB), OlyA6 can form bicomponent 13-meric transmembrane pores in artificial and biological membranes containing the aegerolysin lipid receptor, CPE. This pore formation is the main underlying molecular mechanism of potent and selective insecticidal activity of OlyA6/PlyB complexes against two economically important coleopteran plant pests: the western corn rootworm and the Colorado potato beetle. In contrast to insects, the main sphingolipid in cell membranes of marine invertebrates (i.e., molluscs and cnidarians) is ceramide aminoethylphosphonate (CAEP), a CPE analogue built on a phosphono rather than the usual phosphate group in its polar head. Our targeted lipidomic analyses of the immune cells (hemocytes) of the marine bivalve, the mussel Mytilus galloprovincialis, confirmed the presence of 29.0 mol% CAEP followed by 36.4 mol% of phosphatidylcholine and 34.6 mol% of phosphatidylethanolamine. Further experiments showed the potent binding of OlyA6 to artificial lipid vesicles supplemented with mussel CAEP, and strong lysis of these vesicles by the OlyA6/PlyB mixture. In Mytilus haemocytes, short term exposure (max. 1 h) to the OlyA6/PlyB mixture induced lysosomal membrane destabilization, decreased phagocytic activity, increased Annexin V binding and oxyradical production, and decreased levels of reduced glutathione, indicating rapid damage of endo-lysosomal and plasma membranes and oxidative stress. Our data suggest CAEP as a novel high-affinity receptor for OlyA6 and a target for cytolytic OlyA6/PlyB complexes.

Methyl-β-cyclodextrin suppresses the monocyte-endothelial adhesion triggered by lipopolysaccharide (LPS) or oxidized low-density lipoprotein (oxLDL)

CONTEXT

Recent studies demonstrated the anti-atherosclerotic efficacy of cyclodextrin. However, it remains unclear whether cyclodextrin exerts the anti-atherosclerotic effect via regulating monocyte-endothelial adhesion.

OBJECTIVE

To answer that question by recruiting methyl-β-cyclodextrin (MβCD) as a cyclodextrin representative.

MATERIALS AND METHODS

Human umbilical vein endothelial cells (HUVECs) were not treated, or treated with 1 µg/mL liposaccharide (LPS) or 50 µg/mL oxidized low-density lipoprotein (oxLDL) for 12 h, 5 mM MβCD for 1 h, and LPS/oxLDL (1 and 50 µg/mL, respectively for 12 h) plus MβCD (5 mM for 1 h), respectively. The effects of MβCD on LPS/oxLDL-triggered monocyte-endothelial adhesion and related molecules in signalling pathways were evaluated via confocal microscopy, flow cytometry, RT-PCR, western blotting, and cell adhesion assay.

RESULTS

MβCD with an IC₅₀ of 27.66 mM (1 h treatment) exerted no significant cytotoxicity at ≤5 mM for ≤2 h. Compared with the control, both LPS and oxLDL induced an ∼2-3-fold increase in adhesion molecule expression (ICAM-1 and VCAM-1 at protein and mRNA levels) and NF-κB phosphorylation (p-NF-κB/pP65), an increase in IκB kinase (IKK), and a decrease in phosphorylated protein kinase B (p-Akt), respectively. Moreover, more monocytes (2-fold higher for LPS and 15% higher for oxLDL) were attached on LPS/oxLDL-stimulated HUVECs. 5 mM MβCD reversed the LPS/oxLDL-induced changes back to the control levels.

CONCLUSIONS

MβCD significantly suppresses the LPS/oxLDL-triggered monocyte-endothelial adhesion by downregulating adhesion molecule expression probably via LPS-IKK-NF-κB or oxLDL-Akt-NF-κB pathway. This study demonstrates a potential mechanism of the anti-atherosclerotic efficacy of cyclodextrin from the angle of monocyte-endothelial adhesion.

Lipid raft-disrupting miltefosine preferentially induces the death of colorectal cancer stem-like cells

BACKGROUND

Lipid rafts (LRs), cholesterol-enriched microdomains on cell membranes, are increasingly viewed as signalling platforms governing critical facets of cancer progression. The phenotype of cancer stem-like cells (CSCs) presents significant hurdles for successful cancer treatment, and the expression of several CSC markers is associated with LR integrity. However, LR implications in CSCs remain unclear.

METHODS

This study evaluated the biological and molecular functions of LRs in colorectal cancer (CRC) by using an LR-disrupting alkylphospholipid (APL) drug, miltefosine. The mechanistic role of miltefosine in CSC inhibition was examined through normal or tumour intestinal mouse organoid, human CRC cell, CRC xenograft and miltefosine treatment gene expression profile analyses.

RESULTS

Miltefosine suppresses CSC populations and their self-renewal activities in CRC cells, a CSC-targeting effect leading to irreversible disruption of tumour-initiating potential in vivo. Mechanistically, miltefosine reduced the expression of a set of genes, leading to stem cell death. Among them, miltefosine transcriptionally inhibited checkpoint kinase 1 (CHEK1), indicating that LR integrity is essential for CHEK1 expression regulation. In isolated CD44high CSCs, we found that CSCs exhibited stronger therapy resistance than non-CSC counterparts by preventing cell death through CHEK1-mediated cell cycle checkpoints. However, inhibition of the LR/CHEK1 axis by miltefosine released cell cycle checkpoints, forcing CSCs to enter inappropriate mitosis with accumulated DNA damage and resulting in catastrophic cell death.

CONCLUSION

Our findings underscore the therapeutic potential of LR-targeting APLs for CRC treatment that overcomes the therapy-resistant phenotype of CSCs, highlighting the importance of the LR/CHEK1 axis as a novel mechanism of APLs.

The Association of Controlling Nutritional Status (CONUT) Score with Survival in Patients with Surgically Treated Renal Cell Carcinoma and Upper Tract Urothelial Carcinoma: A Systematic Review and Meta-Analysis

In recent years, Controlling Nutritional Status (CONUT) Score has become widely recognized as a novel index to evaluate the survival in urological neoplasms patients, especially with renal cell carcinoma (RCC) and upper tract urothelial carcinoma (UTUC). The aim of this meta-analysis is to evaluate the prognostic value of CONUT score in patients with RCC and UTUC. PubMed, Web of Science and Embase were searched for data on the association between CONUT score and RCC/UTUC prognosis up to July 29, 2021. Duplicates were excluded, and inclusion/exclusion criteria were applied to all abstracts. We sorted out relevant studies and extracted the risk ratios (RRs) and its 95% confidence interval (CI) for recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). The relationship between gender and survival outcomes was analyzed using univariate cox regression. We analyzed seven studies including 5410 patients in the meta-analysis. A high CONUT score was associated with poor 5-year RFS (RR = 1.27, 95% CI = 1.13-1.43, P = 0.0001), CSS (RR = 1.22, 95% CI = 1.07-1.39, P = 0.003) and OS (RR = 1.24, 95% CI = 1.10-1.41, P = 0.0005). As a result, the association between CONUT score and survival was statistically significant. In addition, gender was not related to survival outcomes. Our results show that the CONUT score is associated with RCC and UTUC outcomes and can serve as a readily available biomarker for managing this disease.

Iron loading induces cholesterol synthesis and sensitizes endothelial cells to TNFα-mediated apoptosis

In plasma, iron is normally bound to transferrin, the principal protein in blood responsible for binding and transporting iron throughout the body. However, in conditions of iron overload when the iron-binding capacity of transferrin is exceeded, non-transferrin-bound iron (NTBI) appears in plasma. NTBI is taken up by hepatocytes and other parenchymal cells via NTBI transporters and can cause cellular damage by promoting the generation of reactive oxygen species. However, how NTBI affects endothelial cells, the most proximal cell type exposed to circulating NTBI, has not been explored. We modeled in vitro the effects of systemic iron overload on endothelial cells by treating primary human umbilical vein endothelial cells (HUVECs) with NTBI (ferric ammonium citrate [FAC]). We showed by RNA-Seq that iron loading alters lipid homeostasis in HUVECs by inducing sterol regulatory element-binding protein 2-mediated cholesterol biosynthesis. We also determined that FAC increased the susceptibility of HUVECs to apoptosis induced by tumor necrosis factor-α (TNFα). Moreover, we showed that cholesterol biosynthesis contributes to iron-potentiated apoptosis. Treating HUVECs with a cholesterol chelator hydroxypropyl-β-cyclodextrin demonstrated that depletion of cholesterol was sufficient to rescue HUVECs from TNFα-induced apoptosis, even in the presence of FAC. Finally, we showed that FAC or cholesterol treatment modulated the TNFα pathway by inducing novel proteolytic processing of TNFR1 to a short isoform that localizes to lipid rafts. Our study raises the possibility that iron-mediated toxicity in human iron overload disorders is at least in part dependent on alterations in cholesterol metabolism in endothelial cells, increasing their susceptibility to apoptosis.

Cancer Cell Preferential Penetration and pH-Responsive Drug Delivery of Oligorutin

We report herein a novel delivery system, derived from the facile enzymatic synthesis of oligorutin (OR), for cancer cell targeting and pH-responsive drug delivery. In this study, we demonstrate that OR could preferentially penetrate cancer cells via the lipid raft-mediated endocytosis pathway, and cell membrane cholesterol was critical to the internalization of OR. The accumulation of OR in the tumor region was further confirmed by an in vivo biodistribution study. Considering the tumor-targeting property of OR, a pH-responsive drug delivery system (OR-BTZ) was developed by covalent conjugation of the catechol groups on OR with antitumor drug bortezomib (BTZ) through a pH-sensitive borate ester bond. OR-BTZ exerted cytotoxicity as well as inhibition of the migration and invasion to hepatoma carcinoma cells and showed no apparent cytotoxicity with liver normal cells. The OR-BTZs also presented significant therapeutic efficacy and low systematic toxicity in the murine hepatocellular carcinoma model. To our knowledge, this study presents the first attempt to exploit the potential of oligoflavonoids for cancer cell-targeted drug delivery and will motivate the development of flavonoids and their derivatives as a new type of biomaterials for tumor-targeted therapy.

Detrimental Effect of Various Preparations of the Human Amniotic Membrane Homogenate on the 2D and 3D Bladder Cancer In vitro Models

Despite being among the ten most common cancers with high recurrence rates worldwide, there have been no major breakthroughs in the standard treatment options for bladder cancer in recent years. The use of a human amniotic membrane (hAM) to treat cancer is one of the promising ideas that have emerged in recent years. This study aimed to investigate the anticancer activity of hAM homogenate on 2D and 3D cancer models. We evaluated the effects of hAM homogenates on the human muscle invasive bladder cancer urothelial (T24) cells, papillary cancer urothelial (RT4) cells and normal porcine urothelial (NPU) cells as well as on human mammary gland non-tumorigenic (MCF10a) cells and low-metastatic breast cancer (MCF7) cells. After 24 h, we observed a gradual detachment of cancerous cells from the culture surface, while the hAM homogenate did not affect the normal cells. The most pronounced effect hAM homogenate had on bladder cancer cells; however, the potency of their detachment was dependent on the treatment protocol and the preparation of hAM homogenate. We demonstrated that hAM homogenate significantly decreased the adhesion, growth, and proliferation of human bladder invasive and papillary cancer urothelial cells and did not affect normal urothelial cells even in 7-day treatment. By using light and electron microscopy we showed that hAM homogenate disrupted the architecture of 2D and 3D bladder cancer models. The information provided by our study highlights the detrimental effect of hAM homogenate on bladder cancer cells and strengthens the idea of the potential clinical application of hAM for bladder cancer treatment.

The P2X7 Receptor in the Maintenance of Cancer Stem Cells, Chemoresistance and Metastasis

Metastasis is the worst prognosis predictor in the clinical course of cancer development. Features of metastatic cancer cells include migratory ability, low degree of differentiation, self-renewal and proliferation potentials, as well as resistance to therapies. Metastatic cells do not present all of the necessary characteristics at once. Indeed, they have a unique phenotypic plasticity, allowing the acquisition of features that make them successful in all steps of metastasis. Cancer stem cells (CSC), the most undifferentiated cells in the tumor mass, display highest metastatic potential and resistance to radio- and chemotherapy. Growing tumors exhibit marked upregulation of P2X7 receptor expression and secrete ATP. Since the P2X7 receptor plays an important role in the maintenance of undifferentiated state of pluripotent cells, its importance on cell fate regulation in the tumor mass is suggested. Considering the extensive crosstalk between CSCs, epithelial-mesenchymal transition, drug resistance and metastasis, current knowledge implicating P2X7 receptor function in these phenomena and new avenues for therapeutic strategies to control metastasis are reviewed.

Attachment of Cancer Urothelial Cells to the Bladder Epithelium Occurs on Uroplakin-Negative Cells and Is Mediated by Desmosomal and Not by Classical Cadherins

Urinary bladder cancer is often multifocal; however, the intraluminal dissemination of the urothelial cancer cells is poorly understood. The involvement of N-cadherin in the adhesion of the cancer urothelial cells to the urothelium had not previously been studied. Therefore, we herein explore the possibility of the intraluminal dissemination of the urothelial cancer cells by evaluating the role of classical cadherins in the adhesion of urothelial cancer cells to the urothelium. We used E-cadherin negative T24 cells and established a T24 Ncad^low cell line with an additionally decreased expression of N-cadherin in the plasma membrane and a decreased secretion of proform of metalloproteinase 2. The labelled T24 and T24 Ncad^low cells were seeded onto urothelial in vitro models. After 24 h in co-culture, unattached cancer cells were rinsed and urothelia with attached cancer urothelial cells were processed for fluorescence and electron microscopy. Both the T24 and T24 Ncad^low cells attached to the urothelium, yet only to the uroplakin-negative urothelial cells. The ultrastructural analysis showed that T24 and T24 Ncad^low cells adhere to poorly differentiated urothelial cells by desmosomes. To achieve this, they first disrupt tight junctions of superficial urothelial cells. This study indicates that the lack of E-cadherin expression and decreased expression of N-cadherin in the plasma membrane of T24 cells does not interfere with their adhesion to the urothelium; therefore, our results suggest that intraluminal dissemination of cancer urothelial cells along the urothelium occurs on uroplakin-negative cells and is desmosome-mediated.

What Can Mushroom Proteins Teach Us about Lipid Rafts?

The lipid raft hypothesis emerged as a need to explain the lateral organization and behavior of lipids in the environment of biological membranes. The idea, that lipids segregate in biological membranes to form liquid-disordered and liquid-ordered states, was faced with a challenge: to show that lipid-ordered domains, enriched in sphingomyelin and cholesterol, actually exist in vivo. A great deal of indirect evidence and the use of lipid-binding probes supported this idea, but there was a lack of tools to demonstrate the existence of such domains in living cells. A whole new toolbox had to be invented to biochemically characterize lipid rafts and to define how they are involved in several cellular functions. A potential solution came from basic biochemical experiments in the late 1970s, showing that some mushroom extracts exert hemolytic activities. These activities were later assigned to aegerolysin-based sphingomyelin/cholesterol-specific cytolytic protein complexes. Recently, six sphingomyelin/cholesterol binding proteins from different mushrooms have been identified and have provided some insight into the nature of sphingomyelin/cholesterol-rich domains in living vertebrate cells. In this review, we dissect the accumulated knowledge and introduce the mushroom lipid raft binding proteins as molecules of choice to study the dynamics and origins of these liquid-ordered domains in mammalian cells.

Cytotoxic Activity of LLO Y406A Is Targeted to the Plasma Membrane of Cancer Urothelial Cells

Identification of novel agents for bladder cancer treatment is highly desirable due to the high incidence of tumor recurrence and the risk of progression to muscle-invasive disease. The key feature of the cholesterol-dependent toxin listeriolysin O mutant (LLO Y406A) is its preferential activity at pH 5.7, which could be exploited either directly for selective targeting of cancer cells or the release of accumulated therapeutics from acidic endosomes. Therefore, our goal was to compare the cytotoxic effect of LLO Y406A on cancer cells (RT4) and normal urothelial cells (NPU), and to identify which cell membranes are the primary target of LLO Y406A by viability assays, life-cell imaging, fluorescence, and electron microscopy. LLO Y406A decreased viability, altered cell morphology, provoked membrane blebbing, and induced apoptosis in RT4 cells, while it did not affect NPU cells. LLO Y406A did not cause endosomal escape in RT4 cells, while the plasma membrane of RT4 cells was revealed as the primary target of LLO Y406A. It has been concluded that LLO Y406A has the ability to selectively eliminate cancer urothelial cells through pore-forming activity at the plasma membrane, without cytotoxic effects on normal urothelial cells. This promising selective activity merits further testing as an anti-cancer agent.

Unconventional Secretion of Nigerolysins A from Aspergillus Species

Aegerolysins are small lipid-binding proteins particularly abundant in fungi. Aegerolysins from oyster mushrooms interact with an insect-specific membrane lipid and, together with MACPF proteins produced by the same organism, form pesticidal pore-forming complexes. The specific interaction with the same membrane lipid was recently demonstrated for nigerolysin A2 (NigA2), an aegerolysin from Aspergillus niger. In Aspergillus species, the aegerolysins were frequently found as secreted proteins, indicating their function in fungal defense. Using immunocytochemistry and live-cell imaging we investigated the subcellular localization of the nigerolysins A in A. niger, while their secretion was addressed by secretion prediction and Western blotting. We show that both nigerolysins A are leaderless proteins that reach the cell exterior by an unconventional protein secretion. NigA proteins are evenly distributed in the cytoplasm of fungal hyphae. A detailed bioinformatics analysis of Aspergillus aegerolysins suggests that the same function occurs only in a limited number of aegerolysins. From alignment, analysis of chromosomal loci, orthology, synteny, and phylogeny it follows that the same or a similar function described for pairs of pesticidal proteins of Pleurotus sp. can be expected in species of the subgenus Circumdati, section Nigri, series Nigri, and some other species with adjacent pairs of putative pesticidal proteins.

The Cells and Extracellular Matrix of Human Amniotic Membrane Hinder the Growth and Invasive Potential of Bladder Urothelial Cancer Cells

Bladder cancer is one of the most common cancers among men in industrialized countries and on the global level incidence and mortality rates are increasing. In spite of progress in surgical treatment and chemotherapy, the prognosis remains poor for patients with muscle-invasive bladder cancer. Therefore, there is a great need for the development of novel therapeutic approaches. The human amniotic membrane (hAM) is a multi-layered membrane that comprises the innermost part of the placenta. It has unique properties that make it suitable for clinical use, such as the ability to promote wound healing and decrease scarring, low immunogenicity, and immunomodulatory, antimicrobial and anticancer properties. This study aimed to investigate the effect of (i) hAM-derived cells and (ii) hAM scaffolds on the growth dynamics, proliferation rate, and invasive potential of muscle-invasive bladder cancer T24 cells. Our results show that 24 and 48 h of co-culturing T24 cells with hAM-derived cells (at 1:1 and 1:4 ratios) diminished the proliferation rate of T24 cells. Furthermore, when seeded on hAM scaffolds, namely (1) epithelium of hAM (e-hAM), (2) basal lamina of hAM (denuded; d-hAM), and (3) stroma of hAM (s-hAM), the growth dynamic of T24 cells was altered and proliferation was reduced, even more so by the e-hAM scaffolds. Importantly, despite their muscle-invasive potential, the T24 cells did not disrupt the basal lamina of hAM scaffolds. Furthermore, we observed a decrease in the expression of epithelial-mesenchymal transition (EMT) markers N-cadherin, Snail and Slug in T24 cells grown on hAM scaffolds and individual T24 cells even expressed epithelial markers E-cadherin and occludin. Our study brings new knowledge on basic mechanisms of hAM affecting bladder carcinogenesis and the results serve as a good foundation for further research into the potential of hAM-derived cells and the hAM extracellular matrix to serve as a novel bladder cancer treatment.

Aegerolysins from the fungal genus Pleurotus - Bioinsecticidal proteins with multiple potential applications

The aegerolysin proteins ostreolysin A6, pleurotolysin A2 and erylysin A are produced by mushrooms of the genus Pleurotus. These aegerolysins can interact specifically with sphingolipid-enriched membranes. In particular, they strongly bind insect cells and to artificial lipid membranes that contain physiologically relevant concentrations of the main invertebrate-specific sphingolipid, ceramide phosphoethanolamine. Moreover, the aegerolysins permeabilise these membranes when combined with their protein partner pleurotolysin B, which contains a membrane-attack-complex/perforin domain. These aegerolysin/ pleurotolysin B complexes show strong and selective toxicity towards western corn rootworm larvae and adults and Colorado potato beetle larvae. Their insecticidal activities arise through aegerolysin binding to ceramide phosphoethanolamine in the insect midgut. This mode of membrane binding is different from those described for similar aegerolysin-based complexes of bacterial origin (e.g., Cry34Ab1/Cry35Ab1), or other Bacillus thuringiensis proteinaceous crystal toxins, which associate with protein receptors. The ability of Pleurotus aegerolysins to specifically interact with sphingolipid-enriched domains in mammalian cells can be further exploited to visualize lipid rafts in living cells, and to treat certain types of tumours and metabolic disorders. Finally, these proteins can strongly enhance fruiting initiation of P. ostreatus even when applied externally. In this review, we summarise the current knowledge of the potential biotechnological and biomedical applications of the Pleurotus aegerolysins, either alone or when complexed with pleurotolysin B, with special emphasis on their bioinsecticidal effects.

The antioxidant vitamin E as a membrane raft modulator: Tocopherols do not abolish lipid domains

The antioxidant vitamin E is a commonly used vitamin supplement. Although the multi-billion dollar vitamin and nutritional supplement industry encourages the use of vitamin E, there is very little evidence supporting its actual health benefits. Moreover, vitamin E is now marketed as a lipid raft destabilizing anti-cancer agent, in addition to its antioxidant behaviour. Here, we studied the influence of vitamin E and some of its vitamers on membrane raft stability using phase separating unilamellar lipid vesicles in conjunction with small-angle scattering techniques and fluorescence microscopy. We find that lipid phase behaviour remains unperturbed well beyond physiological concentrations of vitamin E (up to a mole fraction of 0.10). Our results are consistent with a proposed line active role of vitamin E at the domain boundary. We discuss the implications of these findings as they pertain to lipid raft modification in native membranes, and propose a new hypothesis for the antioxidant mechanism of vitamin E.

Complexation with β-cyclodextrin enhances apoptosis-mediated cytotoxic effect of harman in chemoresistant BRAF-mutated melanoma cells

Harman, a natural β-carboline alkaloid, has recently gained considerable interest due to its anticancer properties. However, its physicochemical characteristics and poor oral bioavailability have been limiting factors for its pharmaceutical development. In this paper, we described the complexation of harman (HAR) with β-cyclodextrin (βCD) as a promising alternative to improve its solubility and consequently its cytotoxic effect in chemoresistant melanoma cells (A2058 cell line). Inclusion complexes (βCD-HAR) were prepared using a simple method and then characterized by FTIR, NMR and SEM techniques. Through in silico studies, the mechanism of complexation of HAR with βCD was elucidated in detail. Both HAR and βCD-HAR promoted cytotoxicity, apoptosis, cell cycle arrest and inhibition of cell migration in melanoma cells. Interestingly, complexation of HAR with βCD enhanced its pro-apoptotic effect by increasing of caspase-3 activity (p < 0.05), probably due to an improvement in HAR solubility. In addition, HAR and βCD-HAR sensitized A2058 cells to vemurafenib, dacarbazine and 5FU treatments, potentializing their cytotoxic activity. These findings suggest that complexation of HAR with natural polymers such as βCD can be useful to improve its bioavailability and antimelanoma activity.

The role of lipid species in membranes and cancer-related changes

Several studies have demonstrated interactions between the two leaflets in membrane bilayers and the importance of specific lipid species for such interaction and membrane function. We here discuss these investigations with a focus on the sphingolipid and cholesterol-rich lipid membrane domains called lipid rafts, including the small flask-shaped invaginations called caveolae, and the importance of such membrane structures in cell biology and cancer. We discuss the possible interactions between the very long-chain sphingolipids in the outer leaflet of the plasma membrane and the phosphatidylserine species PS 18:0/18:1 in the inner leaflet and the importance of cholesterol for such interactions. We challenge the view that lipid rafts contain a large fraction of lipids with two saturated fatty acyl groups and argue that it is important in future studies of membrane models to use asymmetric membrane bilayers with lipid species commonly found in cellular membranes. We also discuss the need for more quantitative lipidomic studies in order to understand membrane function and structure in general, and the importance of lipid rafts in biological systems. Finally, we discuss cancer-related changes in lipid rafts and lipid composition, with a special focus on changes in glycosphingolipids and the possibility of using lipid therapy for cancer treatment.

Magneto-Liposomes as MRI Contrast Agents: A Systematic Study of Different Liposomal Formulations

The majority of the clinically approved iron oxide nanoparticles (IO NPs) used as contrast agents for magnetic resonance imaging (MRI) have been withdrawn from the market either due to safety concerns or lack of profits. To address this challenge, liposomes have been used to prepare IO-based T2 contrast agents. We studied the influence of different phospholipids on the relaxivity (r2) values of magneto-liposomes (MLs) containing magnetic NPs in the bilayer, where a strong correlation between the bilayer fluidity and r2 is clearly shown. Embedding 5-nm IO NPs in the lipid bilayer leads to a significant improvement in their relaxivity, where r2 values range from 153 ± 5 s-1 mM-1 for DPPC/cholesterol/DSPE-PEG (96/50/4) up to 673 ± 12 s-1 mM-1 for DOPC/DSPE-PEG (96/4), compared to "free" IO NPs with an r2 value of 16 s-1 mM-1, measured at 9.4 T MRI scanner. In vitro MRI measurements, together with the ICP-MS analysis, revealed MLs as highly selective contrast agents that were preferentially taken up by cancerous T24 cells, which led to an improvement in the contrast and an easier distinction between the healthy and the cancerous cells. A careful selection of the lipid bilayer to prepare MLs could offer efficient MRI contrast agents, even at very low IO NP concentrations.

IL-33 Is Essential for Adjuvant Effect of Hydroxypropyl-β-Cyclodexrin on the Protective Intranasal Influenza Vaccination

Vaccine adjuvants are traditionally used to augment and modulate the immunogenicity of vaccines, although in many cases it is unclear which specific molecules contribute to their stimulatory activity. We previously reported that both subcutaneous and intranasal administration of hydroxypropyl-β-cyclodextrin (HP-β-CD), a pharmaceutical excipient widely used to improve solubility, can act as an effective adjuvant for an influenza vaccine. However, the mechanisms by which mucosal immune pathway is critical for the intranasal adjuvant activity of HP-β-CD have not been fully delineated. Here, we show that intranasally administered HP-β-CD elicits a temporary release of IL-33 from alveolar epithelial type 2 cells in the lung; notably, IL-33 expression in these cells is not stimulated following the use of other vaccine adjuvants. The experiments using gene deficient mice suggested that IL-33/ST2 signaling is solely responsible for the adjuvant effect of HP-β-CD when it is administered intranasally. In contrast, the subcutaneous injection of HP-β-CD and the intranasal administration of alum, as a damage-associated molecular patterns (DAMPs)-inducing adjuvant, or cholera toxin, as a mucosal adjuvant, enhanced humoral immunity in an IL-33-independent manner, suggesting that the IL-33/ST2 pathway is unique to the adjuvanticity of intranasally administered HP-β-CD. Furthermore, the release of IL-33 was involved in the protective immunity against influenza virus infection which is induced by the intranasal administration of HP-β-CD-adjuvanted influenza split vaccine. In conclusion, our results suggest that an understanding of administration route- and tissue-specific immune responses is crucial for the design of unique vaccine adjuvants.

Cholesterol restricts lymphotoxin β receptor-triggered NF-κB signaling

BACKGROUND

Lymphotoxin β receptor (LTβR) plays important roles in the development of the immune system and immune response. At the cellular level, ligand-bound LTβR activates the pro-inflammatory NF-κB pathway but the detailed mechanisms regulating its signaling remain unknown. Understanding them is of high importance since LTβR and its ligands are promising therapeutic targets. Here, we studied the consequences of perturbed cellular cholesterol content on LTβR-induced NF-κB signaling.

METHODS

To modulate cholesterol availability and/or level in lung carcinoma A549 and H2228, and endothelial HUVEC cells different treatment regimens with filipin, methyl-β-cyclodextrin and simvastatin were applied. LTβR localization was studied by confocal microscopy. The activity of LTβR-induced NF-κB pathway was assessed by measuring the levels of NF-κB pathway inhibitor IκBα and phosphorylation of RelA transcription factor by Western blotting. The NF-κB transcriptional response, production of chemokines and adhesion molecules were examined by qRT-PCR, ELISA, and Western blotting, respectively. Adherence of different types of primary immune cells to epithelial A549 cells and endothelial HUVECs was measured fluorometrically. Interactions of LTβR with its protein partners were investigated by immunoprecipitation.

RESULTS

We showed that filipin-mediated sequestration of cholesterol or its depletion from the plasma membrane with methyl-β-cyclodextrin impaired LTβR internalization and potentiated LTβR-dependent activation of the canonical branch of the NF-κB pathway. The latter was manifested by enhanced degradation of IκBα inhibitor, elevated RelA phosphorylation, substantial increase in the expression of NF-κB target genes encoding, among others, cytokines and adhesion molecules known to play important roles in immune response. It was followed by robust secretion of CXCL8 and upregulation of ICAM1, that favored the adhesion of immune cells (NK and T cells, neutrophils) to A549 cells and HUVECs. Mechanistically, we showed that cholesterol depletion stabilized interactions of ligand-stimulated LTβR with modified forms of TRAF2 and NEMO proteins.

CONCLUSIONS

Our results showed that the reduction of the plasma membrane content of cholesterol or its sequestration strongly potentiated signaling outcome initiated by LTβR. Thus, drugs modulating cholesterol levels could potentially improve efficacy of LTβR-based therapies. Video abstract.

Pore-forming protein complexes from Pleurotus mushrooms kill western corn rootworm and Colorado potato beetle through targeting membrane ceramide phosphoethanolamine

Aegerolysins ostreolysin A (OlyA) and pleurotolysin A (PlyA), and pleurotolysin B (PlyB) with the membrane-attack-complex/perforin domain are proteins from the mushroom genus Pleurotus. Upon binding to sphingomyelin/cholesterol-enriched membranes, OlyA and PlyA can recruit PlyB to form multimeric bi-component transmembrane pores. Recently, Pleurotus aegerolysins OlyA, PlyA2 and erylysin A (EryA) were demonstrated to preferentially bind to artificial lipid membranes containing 50 mol% ceramide phosphoethanolamine (CPE), the main sphingolipid in invertebrate cell membranes. In this study, we demonstrate that OlyA6, PlyA2 and EryA bind to insect cells and to artificial lipid membranes with physiologically relevant CPE concentrations. Moreover, these aegerolysins permeabilize these membranes when combined with PlyB. These aegerolysin/PlyB complexes show selective toxicity toward western corn rootworm larvae and adults and Colorado potato beetle larvae. These data strongly suggest that these aegerolysin/PlyB complexes recognize CPE as their receptor molecule in the insect midgut. This mode of binding is different from those described for similar aegerolysin-based bacterial complexes, or other Bacillus thuringiensis Cry toxins, which have protein receptors. Targeting of Pleurotus aegerolysins to CPE and formation of transmembrane pores in concert with PlyB suggest the use of aegerolysin/PlyB complexes as novel biopesticides for the control of western corn rootworm and Colorado potato beetle.

HDL in Endocrine Carcinomas: Biomarker, Drug Carrier, and Potential Therapeutic

High-density lipoprotein (HDL) have long been studied for their protective role against cardiovascular diseases, however recently relationship between HDL and cancer came into focus. Several epidemiological studies have shown an inverse correlation between HDL-cholesterol (HDL-C) and cancer risk, and some have even implied that HDL-C can be used as a predictive measure for survival prognosis in for specific sub-population of certain types of cancer. HDL itself is an endogenous nanoparticle capable of removing excess cholesterol from the periphery and returning it to the liver for excretion. One of the main receptors for HDL, scavenger receptor type B-I (SR-BI), is highly upregulated in endocrine cancers, notably due to the high demand for cholesterol by cancer cells. Thus, the potential to exploit administration of cholesterol-free reconstituted or synthetic HDL (sHDL) to deplete cholesterol in endocrine cancer cell and stunt their growth of use chemotherapeutic drug loaded sHDL to target payload delivery to cancer cell has become increasingly attractive. This review focuses on the role of HDL and HDL-C in cancer and application of sHDLs as endocrine cancer therapeutics.

Helical organization of microtubules occurs in a minority of tunneling membrane nanotubes in normal and cancer urothelial cells

Tunneling membrane nanotubes (TnTs) are membrane protrusions connecting nearby or distant cells in vitro and in vivo. Functions of TnTs in cellular processes are various and rely on TnT structure, which also depends on cytoskeletal composition. In the present study, we focused on the organization of microtubules (MTs) and intermediate filaments (IFs) in TnTs of urothelial cells. We analysed TnTs of normal porcine urothelial cells, which morphologically and physiologically closely resemble normal human urothelial cells, and of cancer cells derived from invasive human urothelial neoplasm. Wide-field fluorescence, confocal and super-resolution microscopy techniques, together with image analyses and 3D reconstructions enlightened specific MT-IF organization in TnTs, and for the first time revealed that MTs and IFs co-occur in the majority of normal and cancer urothelial cell TnTs. Our findings show that in the initiation segment of TnTs, MTs are cross-linked with each other into filamentous network, however in the middle and the attaching segment of TnT, MTs can helically enwrap IFs, the phenomenon that has not been shown before within the TnTs. In this study, we assess MT-IF co-occurrence in TnTs and present evidence that such helical organization of MTs enwrapping IFs is only occurring in a minority of the TnTs. We also discuss the possible cell-biological and physiological reasons for helical organization of MTs in TnTs.

Complex polymorphisms in endocytosis genes suggest alpha-cyclodextrin as a treatment for breast cancer

Most breast cancer deaths are caused by metastasis and treatment options beyond radiation and cytotoxic drugs, which have severe side effects, and hormonal treatments, which are or become ineffective for many patients, are urgently needed. This study reanalyzed existing data from three genome-wide association studies (GWAS) using a novel computational biostatistics approach (muGWAS), which had been validated in studies of 600-2000 subjects in epilepsy and autism. MuGWAS jointly analyzes several neighboring single nucleotide polymorphisms while incorporating knowledge about genetics of heritable diseases into the statistical method and about GWAS into the rules for determining adaptive genome-wide significance. Results from three independent GWAS of 1000-2000 subjects each, which were made available under the National Institute of Health's "Up For A Challenge" (U4C) project, not only confirmed cell-cycle control and receptor/AKT signaling, but, for the first time in breast cancer GWAS, also consistently identified many genes involved in endo-/exocytosis (EEC), most of which had already been observed in functional and expression studies of breast cancer. In particular, the findings include genes that translocate (ATP8A1, ATP8B1, ANO4, ABCA1) and metabolize (AGPAT3, AGPAT4, DGKQ, LPPR1) phospholipids entering the phosphatidylinositol cycle, which controls EEC. These novel findings suggest scavenging phospholipids as a novel intervention to control local spread of cancer, packaging of exosomes (which prepare distant microenvironment for organ-specific metastases), and endocytosis of β1 integrins (which are required for spread of metastatic phenotype and mesenchymal migration of tumor cells). Beta-cyclodextrins (βCD) have already been shown to be effective in in vitro and animal studies of breast cancer, but exhibits cholesterol-related ototoxicity. The smaller alpha-cyclodextrins (αCD) also scavenges phospholipids, but cannot fit cholesterol. An in-vitro study presented here confirms hydroxypropyl (HP)-αCD to be twice as effective as HPβCD against migration of human cells of both receptor negative and estrogen-receptor positive breast cancer. If the previous successful animal studies with βCDs are replicated with the safer and more effective αCDs, clinical trials of adjuvant treatment with αCDs are warranted. Ultimately, all breast cancer are expected to benefit from treatment with HPαCD, but women with triple-negative breast cancer (TNBC) will benefit most, because they have fewer treatment options and their cancer advances more aggressively.

Hybrid FePt/SiO2/Au nanoparticles as a theranostic tool: in vitro photo-thermal treatment and MRI imaging

We have produced an innovative, theranostic material based on FePt/SiO₂/Au hybrid nanoparticles (NPs) for both, photo-thermal therapy and magnetic resonance imaging (MRI). Furthermore, a new synthesis approach, i.e., Au double seeding, for the preparation of Au nanoshells around the FePt/SiO₂ cores, is proposed. The photo-thermal and the MRI response were first demonstrated on an aqueous suspension of hybrid FePt/SiO₂/Au NPs. The cytotoxicity together with the internalization mechanism and the intracellular fate of the hybrid NPs were evaluated in vitro on a normal (NPU) and a half-differentiated cancerous cell line (RT4). The control samples as well as the normal cell line incubated with the NPs showed no significant temperature increase during the in vitro photo-thermal treatment (ΔT < 0.8 °C) and thus the cell viability remained high (∼90%). In contrast, due to the high NP uptake by the cancerous RT4 cell line, significant heating of the sample was observed (ΔT = 4 °C) and, consequently, after laser irradiation the cell viability dropped significantly to ∼60%. These results further confirm that the hybrid FePt/SiO₂/Au NPs developed in the scope of this work were not only efficient but also highly selective photo-thermal agents. Furthermore, the improvement in the contrast and the easier distinction between the healthy and the cancerous tissues were clearly demonstrated with in vitro MRI experiments, proving that hybrid NPs have an excellent potential to be used as contrast agents.

Detonation nanodiamonds are promising nontoxic delivery system for urothelial cells

Detonation nanodiamonds (DNDs) are carbon-based nanomaterials that are among the most promising nanoparticles available for biomedical applications so far. This is due to their biocompatibility, which could be contributed to their inert core and conformable surface nature. However, DNDs cytotoxicity for urothelial cells and the routes of their internalization remains an open question in the aspect of nanodiamond surface. We therefore analyzed four types of DNDs for cytotoxicity and internalization with normal urothelial cells and two types of cancer urothelial cell lines in vitro. Viability of any of the cell types we used was not compromised with any of four DNDs we evaluated after 24-, 48- and 72-h incubation in three different concentrations of DNDs. Transmission electron microscopy revealed that all four types of DNDs were endocytosed into all three types of urothelial cells tested here. We observed DNDs in endosomes, as well as in multivesicular bodies and multilamellar bodies. These results propose using of DNDs as a delivery system for urological applications in human nanomedicine.

Increased endocytosis of magnetic nanoparticles into cancerous urothelial cells versus normal urothelial cells

The blood-urine barrier is the tightest and most impermeable barrier in the body and as such represents a problem for intravesical drug delivery applications. Differentiation-dependent low endocytotic rate of urothelial cells has already been noted; however, the differences in endocytosis of normal and cancer urothelial cells have not been exploited yet. Here we analysed the endocytosis of rhodamine B isothiocyanate-labelled polyacrylic acid-coated cobalt ferrite nanoparticles (NPs) in biomimetic urothelial in vitro models, i.e., in highly and partially differentiated normal urothelial cells, and in cancer cells of the papillary and invasive urothelial neoplasm. We demonstrated that NPs enter papillary and invasive urothelial neoplasm cells by ruffling of the plasma membrane and engulfment of NP aggregates by macropinocytotic mechanism. Transmission electron microscopy (TEM) and spectrophotometric analyses showed that the efficacy of NPs delivery into normal urothelial cells and intercellular space is largely restricted, while it is significantly higher in cancer urothelial cells. Moreover, we showed that the quantification of fluorescent NP internalization in cells or tissues based on fluorescence detection could be misleading and overestimated without TEM analysis. Our findings contribute to the understanding of endocytosis-mediated cellular uptake of NPs in cancer urothelial cells and reveal a highly selective mechanism to distinguish cancer and normal urothelial cells.

Chitosan hydrochloride has no detrimental effect on bladder urothelial cancer cells

Bladder cancer is among the most common and aggressive human malignant carcinomas, thus targeting and removal of bladder cancer cells is still a challenge. Although it is well known that chitosan hydrochloride (CH-HCl) causes desquamation of normal urothelial cells, its effect on cancer urothelial cells has not been recognized yet. In this in vitro study, we analyzed the cytotoxicity of 0.05% CH-HCl on three urothelial models: two cancer urothelial models, i.e. invasive and papillary urothelial neoplasms, and a normal urothelial model. The cytotoxicity of CH-HCl was evaluated with viability tests, transepithelial resistance (TER) measurements, and electron microscopy. TER measurements showed that 15-minute treatment with CH-HCl caused no reduction in TER of the cancer models, whereas the TER of the normal urothelial model significantly decreased. Furthermore, after CH-HCl treatment, the viability of cancer cells was reduced by only 5%, whereas the viability of normal cells was reduced by 30%. Ultrastructural analysis revealed necrotic cell death in all cases. We have demonstrated that although CH-HCl increases the mortality of cancer urothelial cells, it increases the mortality of normal urothelial cells even more so. However, shorter 2-minute CH-HCl treatment only temporarily increases the permeability of normal urothelial model, i.e. disrupts tight junctions and reduces TER without comprising cell viability, and enables the complete recovery of the permeability barrier after 24h. Overall, our results suggest that CH-HCl cannot be used as a self-sufficient anticancer agent for urothelial bladder cancer treatment; nevertheless a possibility of its use as an enhancer of cytostatic treatment is discussed.

MDR in cancer: Addressing the underlying cellular alterations with the use of nanocarriers

Multidrug resistance (MDR) is associated with a wide range of pathological changes at different cellular and intracellular levels. Nanoparticles (NPs) have been extensively exploited as the carriers of MDR reversing payloads to resistant tumor cells. However, when properly formulated in terms of chemical composition and physicochemical properties, NPs can serve as beyond delivery systems and help overcome MDR even without carrying a load of chemosensitizers or MDR reversing molecular cargos. Whether serving as drug carriers or beyond, a wise design of the nanoparticulate systems to overcome the cellular and intracellular alterations underlying the resistance is imperative. Within the current review, we will initially discuss the cellular changes occurring in resistant cells and how such changes lead to chemotherapy failure and cancer cell survival. We will then focus on different mechanisms through which nanosystems with appropriate chemical composition and physicochemical properties can serve as MDR reversing units at different cellular and intracellular levels according to the changes that underlie the resistance. Finally, we will conclude by discussing logical grounds for a wise and rational design of MDR reversing nanoparticulate systems to improve the cancer therapeutic approaches.

Amphiphilic cyclodextrin nanoparticles

Cyclodextrins are cyclic oligosaccharides obtained by enzymatic digestion of starch. The α-, β- and γ- cyclodextrins contain respectively 6, 7 and 8 glucopyranose units, with primary and secondary hydroxyl groups located on the narrow and wider rims of a truncated cone shape structure. Such structure is that of a hydrophobic inner cavity with a hydrophilic outer surface allowing to interact with a wide range of molecules like ions, protein and oligonucleotides to form inclusion complexes. Many cyclodextrin applications in the pharmaceutical area have been widely described in the literature due to their low toxicity and low immunogenicity. The most important is to increase the solubility of hydrophobic drugs in water. Chemically modified cyclodextrin derivatives have been synthesized to enhance their properties and more specifically their pharmacological activity. Among these, amphiphilic derivatives were designed to build organized molecular structures, through selfassembling systems or by incorporation in lipid membranes, expected to improve the vectorization in the organism of the drug-containing cyclodextrin cavities. These derivatives can form a variety of supramolecular structures such as micelles, vesicles and nanoparticles. The purpose of this review is to summarize applications of amphiphilic cyclodextrins in different areas of drug delivery, particularly in protein and peptide drug delivery and gene delivery. The article highlights important amphiphilic cyclodextrin applications in the design of novel delivery systems like nanoparticles.

Aegerolysins: Lipid-binding proteins with versatile functions

Proteins of the aegerolysin family span many kingdoms of life. They are relatively widely distributed in bacteria and fungi, but also appear in plants, protozoa and insects. Despite being produced in abundance in cells at specific developmental stages and present in secretomes, only a few aegerolysins have been studied in detail. In particular, their organism-specific physiological roles are intriguing. Here, we review published findings to date on the distribution, molecular interactions and biological activities of this family of structurally and functionally versatile proteins, the aegerolysins.

Preoperative controlling nutritional status (CONUT) score as a novel predictive biomarker of survival in patients with localized urothelial carcinoma of the upper urinary tract treated with radical nephroureterectomy

OBJECTIVE

The purpose of this study was to investigate the correlation between the controlling nutritional status (CONUT) score and survival of patients with localized urothelial carcinoma of the upper urinary tract treated with radical nephroureterectomy (RNU).

METHODS AND MATERIALS

We retrospectively enrolled 107 patients. CONUT score was calculated based on the serum albumin concentration, lymphocyte count, and total cholesterol concentration. Patients were classified into 2 groups based on CONUT score. Relapse-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) after RNU were compared between the 2 groups, and predictors of survival were analyzed using Cox proportional hazards regression models.

RESULTS

For CONUT score, the area under the curve was 0.588 and the optimal cutoff value was 3. Twenty-four patients (22.4%) had high CONUT scores. The patients with high CONUT scores had significantly shorter 5-year RFS, CSS, and OS than did those with low CONUT scores (RFS: 50.1% vs. 66.0%; CSS: 28.1% vs. 71.7%; OS: 26.4% vs. 66.8%; all P<0.05). Results of the multivariable analysis, after adjustment for factors such as pT stage, pN stage, tumor grade, presence of lymphovascular invasion, and C-reactive protein level, revealed that CONUT score was an independent predictor of CSS (hazard ratio [HR] = 5.44, P = 0.0016) and OS (HR = 2.90, P = 0.0214) and showed marginal significance for predicting RFS (HR = 2.26, P = 0.0581).

CONCLUSIONS

Preoperative CONUT score helps predict survival in patients with localized urothelial carcinoma of the upper urinary tract treated with RNU.

Ostreolysin A/Pleurotolysin B and Equinatoxins: Structure, Function and Pathophysiological Effects of These Pore-Forming Proteins

Acidic ostreolysin A/pleurotolysin B (OlyA/PlyB, formerly known as ostreolysin (Oly), and basic 20 kDa equinatoxins (EqTs) are cytolytic proteins isolated from the edible mushroom Pleurotus ostreatus and the sea anemone Actinia equina, respectively. Both toxins, although from different sources, share many similar biological activities: (i) colloid-osmotic shock by forming pores in cellular and artificial membranes enriched in cholesterol and sphingomyelin; (ii) increased vascular endothelial wall permeability in vivo and perivascular oedema; (iii) dose-dependent contraction of coronary vessels; (iv) haemolysis with pronounced hyperkalaemia in vivo; (v) bradycardia, myocardial ischemia and ventricular extrasystoles accompanied by progressive fall of arterial blood pressure and respiratory arrest in rodents. Both types of toxins are haemolytic within nanomolar range concentrations, and it seems that hyperkalaemia plays an important role in toxin cardiotoxicity. However, it was observed that the haemolytically more active EqT III is less toxic than EqT I, the most toxic and least haemolytic EqT. In mice, EqT II is more than 30 times more toxic than OlyA/PlyB when applied intravenously. These observations imply that haemolysis with hyperkalaemia is not the sole cause of the lethal activity of both toxins. Additional mechanisms responsible for lethal action of the two toxins are direct effects on heart, coronary vasoconstriction and related myocardial hypoxia. In this review, we appraise the pathophysiological mechanisms related to the chemical structure of OlyA/PlyB and EqTs, as well as their toxicity.

Characterisation of plasmalemmal shedding of vesicles induced by the cholesterol/sphingomyelin binding protein, ostreolysin A-mCherry

Ostreolysin A (OlyA) is a 15-kDa protein that binds selectively to cholesterol/sphingomyelin membrane nanodomains. This binding induces the production of extracellular vesicles (EVs) that comprise both microvesicles with diameters between 100nm and 1μm, and larger vesicles of around 10-μm diameter in Madin-Darby canine kidney cells. In this study, we show that vesiculation of these cells by the fluorescent fusion protein OlyA-mCherry is not affected by temperature, is not mediated via intracellular Ca2+ signalling, and does not compromise cell viability and ultrastructure. Seventy-one proteins that are mostly of cytosolic and nuclear origin were detected in these shed EVs using mass spectroscopy. In the cells and EVs, 218 and 84 lipid species were identified, respectively, and the EVs were significantly enriched in lysophosphatidylcholines and cholesterol. Our collected data suggest that OlyA-mCherry binding to cholesterol/sphingomyelin membrane nanodomains induces specific lipid sorting into discrete patches, which promotes plasmalemmal blebbing and EV shedding from the cells. We hypothesize that these effects are accounted for by changes of local membrane curvature upon the OlyA-mCherry-plasmalemma interaction. We suggest that the shed EVs are a potentially interesting model for biophysical and biochemical studies of cell membranes, and larger vesicles could represent tools for non-invasive sampling of cytosolic proteins from cells and thus metabolic fingerprinting.

Defective quorum sensing of acute lymphoblastic leukemic cells: evidence of collective behavior of leukemic populations as semi-autonomous aberrant ecosystems

Quorum sensing (QS) is a generic term used to describe cell-cell communication and collective decision making by bacterial and social insects to regulate the expression of specific genes in controlling cell density and other properties of the populations in response to nutrient supply or changes in the environment. QS mechanisms also have a role in higher organisms in maintaining homeostasis, regulation of the immune system and collective behavior of cancer cell populations. In the present study, we used a p190(BCR-ABL) driven pre-B acute lymphoblastic leukemia (ALL3) cell line derived from the pleural fluid of a terminally ill patient with ALL to test the QS hypothesis in leukemia. ALL3 cells don't grow at low density (LD) in liquid media but grow progressively faster at increasingly high cell densities (HD) in contrast to other established leukemic cell lines that grow well at very low starting cell densities. The ALL3 cells at LD are poised to grow but shortly die without additional stimulation. Supernates of ALL3 cells (HDSN) and some other primary cells grown at HD stimulate the growth of the LD ALL3 cells without which they won't survive. To get further insight into the activation processes we performed microarray analysis of the LD ALL3 cells after stimulation with ALL3 HDSN at days 1, 3, and 6. This screen identified several candidate genes, and we linked them to signaling networks and their functions. We observed that genes involved in lipid, cholesterol, fatty acid metabolism, and B cell activation are most up- or down-regulated upon stimulation of the LD ALL3 cells using HDSN. We also discuss other pathways that are differentially expressed upon stimulation of the LD ALL3 cells. Our findings suggest that the Ph+ ALL population achieves dominance by functioning as a collective aberrant ecosystem subject to defective quorum-sensing regulatory mechanisms.

The barrier function of organotypic non-melanoma skin cancer models

Non-melanoma skin cancer (NMSC) is the most frequent human cancer with continuously rising incidences worldwide. Herein, we investigated the molecular basis for the impaired skin barrier function of organotypic NMSC models. We unraveled disturbed epidermal differentiation by reflectance confocal microscopy and histopathological evaluation. While the presence of claudin-4 and occludin were distinctly reduced, zonula occludens protein-1 was more wide-spread, and claudin-1 was heterogeneously distributed within the NMSC models compared with normal reconstructed human skin. Moreover, the cancer altered stratum corneum lipid packing and profile with decreased cholesterol content, increased phospholipid amount, and altered ceramide subclasses. These alterations contributed to increased surface pH and to 1.5 to 2.6-fold enhanced caffeine permeability of the NMSC models. Three topical applications of ingenol mebutate gel (0.015%) caused abundant epidermal cell necrosis, decreased Ki-67 indices, and increased lactate dehydrogenase activity. Taken together, our study provides new biological insights into the microenvironment of organotypic NMSC models, improves the understanding of the disease model by revealing causes for impaired skin barrier function in NMSC models at the molecular level, and fosters human cell-based approaches in preclinical drug evaluation.

Comparative lipidomic study of urothelial cancer models: association with urothelial cancer cell invasiveness

A joint NMR/LC-MS approach allows to establish significant differences in the lipidoma of invasive urothelial carcinoma cells (T24) with respect to noninvasive urothelial cells (RT4).