LysoTracker and MitoTracker Red are transport substrates of P-glycoprotein: implications for anticancer drug design evading multidrug resistance

Preparation, characterization and antioxidant and anticancerous potential of Quercetin loaded β-glucan particles derived from mushroom and yeast

β-glucans are polysaccharides found in the cell walls of various fungi, bacteria and cereals. β-glucan have been found to show various kinds of anti-inflammatory, antimicrobial, antidiabetic antioxidant and anticancerous activities. In the present study, we have isolated β-glucan from the baker's yeast Saccharomyces cerevisiae and white button mushroom Agaricus bisporus and tested their antioxidant potential and anticancerous activity against prostate cancer cell line PC3. Particles were characterized with zeta sizer and further with FTIR that confirmed that the isolated particles are β-glucan and alginate sealing made slow and sustained release of the Quercetin from the β-glucan particles. Morphological analysis of the hollow and Quercetin loaded β-glucan was performed with the SEM analysis and stability was analyzed with TGA and DSC analysis that showed the higher stability of the alginate sealed particles. Assessments of the antioxidant potential showed that Quercetin loaded particles were having higher antioxidant activity than hollow β-glucan particles. Cell viability of the PC3 cells was examined with MTT assay and it was found that Quercetin loaded alginate sealed Agaricus bisporus derived β-glucan particles were having lowest IC50. Further ROS generation was found to increase in a dose dependent manner. Apoptosis detection was carried out with Propidium iodide and AO/EtBr staining dye which showed significant death in the cells treated with higher concentration of the particles. Study showed that particles derived from both of the sources were having efficient anticancer activity and showing a dose dependent increase in cell death in PC3 cells upon treatment.

Carrier-free chemo-phototherapeutic nanomedicines with endo/lysosomal escape function enhance the therapeutic effect of drug molecules in tumors

Carrier-free nanomedicines offer advantages of extremely high drug loading capacity (>80%), minimal non-drug constituent burden, and facile preparation processes. Numerous studies have proved that multimodal cancer therapy can enhance chemotherapy efficiency and mitigate multi-drug resistance (MDR) through synergistic therapeutic effects. Upon penetration into the tumor matrix, nanoparticles (NPs) are anticipated to be uptaken by cancer cells, primarily through clathrin-meditated endocytosis pathways, leading to their accumulation in endosomes/lysosomes within cells. However, endo/lysosomes exhibit a highly degradative environment for organic NPs and drug molecules, often resulting in treatment failure. Hence, this study designed a lysosomal escape mechanism with carrier-free nanomedicine, combining the chemotherapeutic drug, curcumin (Cur), and the photothermal/photodynamic therapeutic drug, indocyanine green (ICG), for synergistic cancer treatment (ICG-Cur NPs) via a facile preparation process. To facilitate endo/lysosomal escape, ICG-Cur NPs were modified with metal-phenolic networks (MPNs) of different thickness. The results indicate that a thick MPN coating promotes rapid endo/lysosomal escape of ICG-Cur NPs within 4 h and enhances the photothermal conversion efficiency of ICG-Cur NPs by 55.8%, significantly improving anticancer efficacy in both chemo- and photo-therapies within 3D solid tumor models. This finding underscores the critical role of endo/lysosomal escape capacity in carrier-free drug NPs for therapeutic outcomes and offers a facile solution to achieve it.

Genetically Encoded and Modular SubCellular Organelle Probes (GEM-SCOPe) reveal lysosomal and mitochondrial dysfunction driven by PRKN knockout

Cellular processes including lysosomal and mitochondrial dysfunction are implicated in the development of many diseases. Quantitative visualization of mitochondria and lysosoesl is crucial to understand how these organelles are dysregulated during disease. To address a gap in live-imaging tools, we developed GEM-SCOPe (Genetically Encoded and Modular SubCellular Organelle Probes), a modular toolbox of fluorescent markers designed to inform on localization, distribution, turnover, and oxidative stress of specific organelles. We expressed GEM-SCOPe in differentiated astrocytes and neurons from a human pluripotent stem cell PRKN-knockout model of Parkinson's disease and identified disease-associated changes in proliferation, lysosomal distribution, mitochondrial transport and turnover, and reactive oxygen species. We demonstrate GEM-SCOPe is a powerful panel that provide critical insight into the subcellular mechanisms underlying Parkinson's disease in human cells. GEM-SCOPe can be expanded upon and applied to a diversity of cellular models to glean an understanding of the mechanisms that promote disease onset and progression.

Lighting Up Nucleolus To Report Mitochondria Damage Using a Mitochondria-to-Nucleolus Migration Probe

Visualization of the mitochondrial state is crucial for tracking cell life processes and diagnosing disease, while fluorescent probes that can accurately assess mitochondrial status are currently scarce. Herein, a fluorescent probe named "SYN" was designed and prepared, which can target mitochondria via the mitochondrial membrane potential. Upon pathology or external stimulation, SYN can be released from the mitochondria and accumulate in the nucleolus to monitor the status of mitochondria. During this process, the brightness of the nucleolus can then serve as an indicator of mitochondrial damage. SYN has demonstrated excellent photostability in live cells as well as an extremely inert fluorescence response to bioactive molecules and the physiological pH environment of live cells. Spectroscopic titration and molecular docking studies have revealed that SYN can be lit up in nucleoli due to the high viscosity of the nucleus and the strong electrostatic interaction with the phosphate backbone of RNA. This probe is expected to be an exceptional tool based on its excellent imaging properties for tracking mitochondrial state in live cells.

A high-throughput lysosome trafficking assay guides ligand selection and elucidates differences in CD22-targeted nanodelivery

Targeted nanoparticles offer potential to selectively deliver therapeutics to cells; however, their subcellular fate following endocytosis must be understood to properly design mechanisms of drug release. Here we describe a nanoparticle platform and associated cell-based assay to observe lysosome trafficking of targeted nanoparticles in live cells. The nanoparticle platform utilizes two fluorescent dyes loaded onto PEG-poly(glutamic acid) and PEG-poly(Lysine) block co-polymers that also comprise azide reactive handles on PEG termini to attach antibody-based targeting ligands. Fluorophores were selected to be pH-sensitive (pHrodo Red) or pH-insensitive (Alexafluor 488) to report when nanoparticles enter low pH lysosomes. Dye-labelled block co-polymers were further assembled into polyion complex micelle nanoparticles and crosslinked through amide bond formation to form stable nano-scaffolds for ligand attachment. Cell binding and lysosome trafficking was determined in live cells by fluorescence imaging in 96-well plates and quantification of red- and green-fluorescence signals over time. The platform and assay was validated for selection of optimal antibody-derived targeting ligands directed towards CD22 for nanoparticle delivery. Kinetic analysis of uptake and lysosome trafficking indicated differences between ligand types and the ligand with the highest lysosome trafficking efficiency translated into effective DNA delivery with nanoparticles bearing the optimal ligand.

The SMAC mimetic GDC-0152 is a direct ABCB1-ATPase activity modulator and BIRC5 expression suppressor in cancer cells

Upregulation of the multidrug efflux pump ABCB1/MDR1 (P-gp) and the anti-apoptotic protein BIRC5/Survivin promotes multidrug resistance in various human cancers. GDC-0152 is a DIABLO/SMAC mimetic currently being tested in patients with solid tumors. However, it is still unclear whether GDC-0152 is therapeutically applicable for patients with ABCB1-overexpressing multidrug-resistant tumors, and the molecular mechanism of action of GDC-0152 in cancer cells is still incompletely understood. In this study, we found that the potency of GDC-0152 is unaffected by the expression of ABCB1 in cancer cells. Interestingly, through in silico and in vitro analysis, we discovered that GDC-0152 directly modulates the ABCB1-ATPase activity and inhibits ABCB1 multidrug efflux activity at sub-cytotoxic concentrations (i.e., 0.25×IC50 or less). Further investigation revealed that GDC-0152 also decreases BIRC5 expression, induces mitophagy, and lowers intracellular ATP levels in cancer cells at low cytotoxic concentrations (i.e., 0.5×IC50). Co-treatment with GDC-0152 restored the sensitivity to the known ABCB1 substrates, including paclitaxel, vincristine, and YM155 in ABCB1-expressing multidrug-resistant cancer cells, and it also restored the sensitivity to tamoxifen in BIRC5-overexpressing tamoxifen-resistant breast cancer cells in vitro. Moreover, co-treatment with GDC-0152 restored and potentiated the anticancer effects of paclitaxel in ABCB1 and BIRC5 co-expressing xenograft tumors in vivo. In conclusion, GDC-0152 has the potential for use in the management of cancer patients with ABCB1 and BIRC5-related drug resistance. The findings of our study provide essential information to physicians for designing a more patient-specific GDC-0152 clinical trial program in the future.

The Influence of Lysosomal Stress on Dental Pulp Stem Cell-Derived Schwann Cells

BACKGROUND

Dysregulation of the endo-lysosomal-autophagy pathway has been identified as a critical factor in the pathology of various demyelinating neurodegenerative diseases, including peripheral neuropathies. This pathway plays a crucial role in transporting newly synthesized myelin proteins to the plasma membrane in myelinating Schwann cells, making these cells susceptible to lysosome-related dysfunctions. Nevertheless, the specific impact of lysosomal dysfunction in Schwann cells and its contribution to neurodegeneration remain poorly understood.

METHODS

We aim to mimic lysosomal dysfunction in Schwann cells using chloroquine, a lysosomal dysfunction inducer, and to monitor lysosomal leakiness, Schwann cell viability, and apoptosis over time. Additionally, due to the ethical and experimental issues associated with cell isolation and the culturing of human Schwann cells, we use human dental pulp stem cell-derived Schwann cells (DPSC-SCs) as a model in our study.

RESULTS

Chloroquine incubation boosts lysosomal presence as demonstrated by an increased Lysotracker signal. Further in-depth lysosomal analysis demonstrated an increased lysosomal size and permeability as illustrated by a TEM analysis and GAL3-LAMP1 staining. Moreover, an Alamar blue assay and Caspase-3 staining demonstrates a reduced viability and increased apoptosis, respectively.

CONCLUSIONS

Our data indicate that prolonged lysosomal dysfunction leads to lysosomal permeability, reduced viability, and eventually apoptosis in human DPSC-SCs.

HMGB1 promotes mitochondrial transfer between hepatocellular carcinoma cells through RHOT1 and RAC1 under hypoxia

Mitochondrial transfer plays an important role in various diseases, and many mitochondrial biological functions can be regulated by HMGB1. To explore the role of mitochondrial transfer in hepatocellular carcinoma (HCC) and its relationship with HMGB1, field emission scanning electron microscopy, immunofluorescence, and flow cytometry were used to detect the mitochondrial transfer between HCC cells. We found that mitochondrial transfer between HCC cells was confirmed using tunnel nanotubes (TNTs). The transfer of mitochondria from the highly invasive HCC cells to the less invasive HCC cells could enhance the migration and invasion ability of the latter. The hypoxic conditions increased the mitochondrial transfer between HCC cells. Then the mechanism was identified using co-immunoprecipitation, luciferase reporter assay, and chromatin immunoprecipitation. We found that RHOT1, a mitochondrial transport protein, promoted mitochondrial transfer and the migration and metastasis of HCC cells during this process. Under hypoxia, HMGB1 further regulated RHOT1 expression by increasing the expression of NFYA and NFYC subunits of the NF-Y complex. RAC1, a protein associated with TNTs formation, promoted mitochondrial transfer and HCC development. Besides, HMGB1 regulated RAC1 aggregation to the cell membrane under hypoxia. Finally, the changes and significance of related molecules in clinical samples of HCC were analyzed using bioinformatics and tissue microarray analyses. We found that HCC patients with high HMGB1, RHOT1, or RAC1 expression exhibited a relatively shorter overall survival period. In conclusion, under hypoxic conditions, HMGB1 promoted mitochondrial transfer and migration and invasion of HCC cells by increasing the expression of mitochondrial transport protein RHOT1 and TNTs formation-related protein RAC1.

Palladium (II) compounds containing oximes as promising antitumor agents for the treatment of osteosarcoma: An in vitro and in vivo comparative study with cisplatin

Drug resistance, evasion of cell death and metastasis are factors that contribute to the low cure rate and disease-free survival in osteosarcomas (OS). In this study, we demonstrated that a new class of oxime-containing organometallic complexes called Pd-BPO (O3) and Pd-BMO (O4) are more cytotoxic than cisplatin (CDDP) for SaOS-2 and U2OS cells using the MTT assay. Annexin-FITC/7-AAD staining demonstrated a greater potential for palladium-oxime complexes to induce death in SaOS-2 cells than CDDP, an event confirmed using the pan-caspase inhibitor Z-VAD-FMK. Compared to CDDP, only palladium-oxime complexes eradicated the clonogenicity of SaOS-2 cells after 7 days of treatment. The involvement of the lysosome-mitochondria axis in the cell death-inducing properties of the complexes was also evaluated. Using LysoTracker Red to label the acidic organelles of SaOS-2 cells treated with the O3 and O4 complexes, a decrease in the fluorescence intensity of this probe was observed in relation to CDDP and the control. Lysosomal membrane permeabilization (LMP) was also induced by the O3 and O4 complexes in an assay using acridine orange (A/O). The greater efficiency of the complexes in depolarizing the mitochondrial membrane compared to SaOS-2 cells treated with CDDP was also observed using TMRE (tetramethyl rhodamine, ethyl ester). For in vivo studies, C. elegans was used and demonstrated that both complexes reduce body bends and pharyngeal pumping after 24 h of treatment to the same extent as CDDP. We conclude that both palladium-oxime complexes are more effective than CDDP in inducing tumor cell death. The toxicity of these complexes to C. elegans was like that induced by CDDP. These results encourage preclinical studies aimed at developing more effective drugs for the treatment of osteosarcoma (OS). Furthermore, we propose palladium-oxime complexes as a new class of antineoplastic agents.

MitoTracker: A useful tool in need of better alternatives

The fluorescence viewing of mitochondria is commonly performed by MitoTracker, a lipophilic cationic dye that is taken up by the mitochondria. In this forum, we highlight several issues that may occur with MitoTracker, including staining of other organelles. Our aim is to offer alternative dyes and discuss their advantages and disadvantages. We also offer options for software with alternatives to MitoTracker to expedite future experimental design.

Phytocompound identification of aqueous Zingiber officinale rhizome (ZOME) extract reveals antiproliferative and reactive oxygen species mediated apoptotic induction within cervical cancer cells: an in vitro and in silico approach

The prevalence of cervical cancer in women is in the fourth position among various other types of cancer globally. Many established therapies, including surgery, chemotherapy, and immunomodulation, are present, but high levels of side effects cause mortality and morbidity among the patients. Zingiber officinale rhizome (ZOME) has been potentially used to cure a variety of ailments and diseases. The aqueous ZOME extract also contains ample phytochemical constituents having anticancer effects on different cancers. The cell viability of HeLa cells was evaluated using MTT assay with IC50 at 97 µg/mL. Furthermore, a significant level of ROS generation causes the apoptosis of the cells. Nuclear staining dye DAPI and Hoechst 33342 showed DNA's fragmented and condensed form. Propidium Iodide staining showed necrotic or late-apoptotic cells. While acidic organelle dye LysoTracker and MitoTracker dye along with dual staining showed significant results. In silico studies were carried out using identified phytochemicals from GC-MS analysis with pharmacokinetics properties (ADMET), and targeted toward receptor proteins for molecular docking. Ligands with high docked scores were subjected to molecular dynamics simulations at 310 K for 100 ns. In vitro and in silico investigations in our studies showed that aqueous ZOME extract can be used as an efficient therapy against cervical cancer treatment as it showed significant cytotoxic and antiproliferative effects toward the HeLa cell line.Communicated by Ramaswamy H. Sarma.

pH-Responsive Drug Delivery Nanoplatforms as Smart Carriers of Unsymmetrical Bisacridines for Targeted Cancer Therapy

Selective therapy and controlled drug release at an intracellular level remain key challenges for effective cancer treatment. Here, we employed folic acid (FA) as a self-navigating molecule in nanoconjugates containing quantum dots (QDs) and β-cyclodextrin (β-CD) for the delivery of antitumor unsymmetrical bisacridine compound (C-2028) to lung and prostate cancers as well as normal cells. The bisacridine derivative can form the inclusion complex with β-cyclodextrin molecule, due to the presence of a planar fragment in its structure. The stability of such a complex is pH-dependent. The drug release profile at different pH values and the mechanism of C-2028 release from QDs-β-CD-FA nanoconjugates were investigated. Next, the intracellular fate of compounds and their influence on lysosomal content in the cells were also studied. Confocal Laser Scanning Microscopy studies proved that all investigated compounds were delivered to acidic organelles, the pH of which promoted an increased release of C-2028 from its nanoconjugates. Since the pH in normal cells is higher than in cancer cells, the release of C-2028 from its nanoconjugates is decreased in these cells. Additionally, we obtained the concentration profiles of C-2028 in the selected cells treated with unbound C-2028 or nanoconjugate by the HPLC analysis.

Prophylaxis of posterior capsule opacification through autophagy activation with indomethacin-eluting intraocular lens

Posterior capsule opacification (PCO) is the most common long-term postoperative complication of cataract surgery, leading to secondary vision loss. Optimized intraocular lens (IOL) structure and appropriate pharmacological intervention, which provides physical barriers and biological inhibition, respectively, can block the migration, proliferation, and epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) for PCO prophylaxis. Herein, a novel indomethacin-eluting IOL (INDOM-IOL) with an optimized sharper edge and a sustained drug release behavior was developed for PCO prevention. Indomethacin (INDOM), an ophthalmic non-steroidal anti-inflammatory drug (NSAID) used for postoperative ocular inflammation, was demonstrated to not only be able to suppress cell migration and down-regulate the expression of cyclooxygenase-2 (COX-2) and EMT markers, including alpha-smooth muscle actin (α-SMA) and cyclin D1, but also promote the autophagy activation in LECs. Additionally, autophagy was also verified to be a potential therapeutic target for the down-regulation of EMT in LECs. The novel IOL, serving as a drug delivery platform, could carry an adjustable dose of hydrophobic indomethacin with sustained drug release ability for more than 28 days. In the rabbit PCO model, the indomethacin-eluting IOL showed excellent anti-inflammatory and anti-PCO effects. In summary, indomethacin is an effective pharmacological intervention in PCO prophylaxis, and the novel IOL we developed prevented PCO in vivo under its sustained indomethacin release property, which provided a promising approach for PCO prophylaxis in clinical application.

Delay of EGF-Stimulated EGFR Degradation in Myotonic Dystrophy Type 1 (DM1)

Myotonic dystrophy type 1 (DM1) is an autosomal dominant disease caused by a CTG repeat expansion in the 3′ untranslated region of the dystrophia myotonica protein kinase gene. AKT dephosphorylation and autophagy are associated with DM1. Autophagy has been widely studied in DM1, although the endocytic pathway has not. AKT has a critical role in endocytosis, and its phosphorylation is mediated by the activation of tyrosine kinase receptors, such as epidermal growth factor receptor (EGFR). EGF-activated EGFR triggers the internalization and degradation of ligand–receptor complexes that serve as a PI3K/AKT signaling platform. Here, we used primary fibroblasts from healthy subjects and DM1 patients. DM1-derived fibroblasts showed increased autophagy flux, with enlarged endosomes and lysosomes. Thereafter, cells were stimulated with a high concentration of EGF to promote EGFR internalization and degradation. Interestingly, EGF binding to EGFR was reduced in DM1 cells and EGFR internalization was also slowed during the early steps of endocytosis. However, EGF-activated EGFR enhanced AKT and ERK1/2 phosphorylation levels in the DM1-derived fibroblasts. Therefore, there was a delay in EGF-stimulated EGFR endocytosis in DM1 cells; this alteration might be due to the decrease in the binding of EGF to EGFR, and not to a decrease in AKT phosphorylation.

Pyrimethamine induces phototoxicity in human keratinocytes via lysosomal and mitochondrial dependent signaling pathways under environmental UVA and UVB exposure

Pyrimethamine (PYR) is used to treat parasitic infections including toxoplasmosis, pneumonia and cystoisosporiasis in HIV patients. Various oral medicines have shown phototoxicity therefore, we aimed to study the phototoxicity of PYR and its molecular mechanism involving stress responsive lysosomal protein Lamp2 and mitochondrial mediated signaling pathway under normal UVA/B exposure. We found that photodegradation and subsequent photoproduct formation was evident through LCMS/MS analysis. Photosensitized PYR produces ROS that cause damage to DNA, cell membrane and membrane bound organelles in human keratinocytes. PYR triggered cytotoxicity and phototoxicity that was evident through MTT and NRU assay respectively. Intracellular ROS generation caused phosphatidyl serine (PS) translocation in cell membrane, lysosome membrane permeabilization (LMP) and mitochondrial membrane potential (MMP) collapse that was further validated through caspase3 activation. DNA damage was measured as tail DNA formation and cell cycle arrest in G1 phase. Photosensitized PYR induces oxidative stress in the form of overexpression of Lamp2 that ultimately led to cellular apoptosis. Moreover, the effects of UVB were higher than UVA, probably due to its direct interaction with various macromolecules. We propose that photoexcited PYR may be harmful to human health even at normal sunlight exposure. Therefore, protective procedures should be practiced during PYR medication.

In vitro elucidation of antioxidant, antiproliferative, and apoptotic potential of yeast-derived β-1,3-glucan particles against cervical cancer cells

Cancer is the leading cause of mortality worldwide and in particular is the fourth most common cause of mortality in women every year. Conventional treatments for cancer are chemotherapy and radiation therapy, which have various kinds of side effects. Hence, there is a high need to develop alternative, efficient, and safer therapies for cancer treatment. β-Glucan, a novel polysaccharide isolated from baker’s yeast Saccharomyces cerevisiae, shows noteworthy cytotoxicity toward a variety of cancer cell lines in vitro. In this research, we characterized the β-glucan with high-performance thin-layer chromatography (HPTLC) analysis and found that d-glucose units with β-1,3 links are the major component of the extracted β-glucan particles. Fourier transform IR (FTIR) analysis confirmed a β-(1→3)-linked glucan structure. In vitro cell cytotoxicity was evaluated by MTT with IC₅₀ 136 μg/ml, and therapeutic potential was assessed by various assays using values below and above the IC₅₀. A significant reactive oxygen species (ROS) generation at 50–150 μg/ml of concentrations indicated the apoptosis of cervical cancer cells. Along with ROS generation, these concentrations were also found to induce morphological changes such as fragmentation in DNA upon staining HeLa cells with DAPI. Mitochondrial membrane potential was significantly reduced after increasing the dose of treatment, assessed with the help of MitoTracker dye. Hence, by all these experimental supports, we observed that β-glucan has the potential to slow down the growth of cervical cancer cells, and it can be further investigated for unfolding its complete anticancer potential.

Application of meso-CF3-Fluorophore BODIPY with Phenyl and Pyrazolyl Substituents for Lifetime Visualization of Lysosomes

A bright far-red emitting unsymmetrical meso-CF₃-BODIPY fluorescent dye with phenyl and pyrazolyl substituents was synthesized by condensation of trifluoropyrrolylethanol with pyrazolyl-pyrrole, with subsequent oxidation and complexation of the formed dipyrromethane. This BODIPY dye exhibits optical absorption at λ_ab ≈ 610-620 nm and emission at λ_em ≈ 640-650 nm. The BODIPY was studied on Ehrlich carcinoma cells as a lysosome-specific fluorescent dye that allows intravital staining of cell structures with subsequent real-time monitoring of changes occurring in the cells. It was also shown that the rate of uptake by cells, the rate of intracellular transport into lysosomes, and the rate of saturation of cells with the dye depend on its concentration in the culture medium. A concentration of 5 μM was chosen as the most suitable BODIPY concentration for fluorescent staining of living cell lysosomes, while a concentration of 100 μM was found to be toxic to Ehrlich carcinoma cells.

Electronic transitions in noncovalent BODIPY dimers: TD-DFT study

Theoretical computations have been performed on the absorption spectra of (8-R-TMB)₂ dimers with varying character of substituents at the 8 position (meso) at monomers units (R = NH₂, OH, CH₃, H, COH, CF₃, CN). The obtained results (TD-CAM-B3LYP) show that the first four lower transitions of studied dimers (S₀ → S_i, i = 1-4) are intrinsically linked with delocalized HOMO and LUMO orbitals of the two monomers, which constitute a dimer. For all the dimers, S₀ → S₁ and S₀ → S₃ transitions are strongly forbidden, whereas S₀ → S₂ and S₀ → S₄ are allowed. There is a good agreement between the TD-CAM-B3LYP theory and the simple model of exciton coupling for two identical chromophores with the planes of two moieties, which are stacked upon each other. Intensities of the allowed transitions depend strongly on the nature of the substituent at the meso position. For the dimers with monomer units bearing electron-donor groups, S₀ → S₂ transitions are more intense compared with S₀ → S₄ ones. As the donor properties of the meso substituents diminish and electron acceptor properties enlarge, the intensity of these transitions becomes lower, whereas that of S₀ → S₄ transitions becomes higher. For the dimers with NH₂ and CN substituents, the almost inverse ratio of intensities of the transitions discussed is observed (for example, f = 0.80 and 0.06 (in the case of NH₂) and f = 0.09 and 0.72 (CN) for S₀ → S₂ and S₀ → S₄, respectively). Protonation of the tertiary amine function drastically 'switches off' its electron-donating properties. As a result, the red shift of the bands and redistribution of intensities of the allowed S₀ → S₂ and S₀ → S₄ transitions is predicted for protonated forms of the (8-NH₂-TMB)₂ dimer. This peculiarity can be of especial importance for the design of dimers with a sensor function.

Organelle Interaction and Drug Discovery: Towards Correlative Nanoscopy and Molecular Dynamics Simulation

The inter-organelle interactions, including the cytomembrane, endoplasmic reticulum, mitochondrion, lysosome, dictyosome, and nucleus, play the important roles in maintaining the normal function and homeostasis of cells. Organelle dysfunction can lead to a range of diseases (e.g., Alzheimer’s disease (AD), Parkinson’s disease (PD), and cancer), and provide a new perspective for drug discovery. With the development of imaging techniques and functional fluorescent probes, a variety of algorithms and strategies have been developed for the ever-improving estimation of subcellular structures, organelle interaction, and organelle-related drug discovery with accounting for the dynamic structures of organelles, such as the nanoscopy technology and molecular dynamics (MD) simulations. Accordingly, this work summarizes a series of state-of-the-art examples of the recent progress in this rapidly changing field and uncovering the drug screening based on the structures and interactions of organelles. Finally, we propose the future outlook for exciting applications of organelle-related drug discovery, with the cooperation of nanoscopy and MD simulations.

Streptococcus agalactiae-induced autophagy of bovine mammary epithelial cell via PI3K/AKT/mTOR pathway

Streptococcus agalactiae (S. agalactiae) infection is a significant cause of mastitis, resulting in loss of cellular homeostasis and tissue damage. Autophagy plays an essential function in cell survival, defense, and the preservation of cellular homeostasis, and is often part of the response to pathogenic challenge. However, the effect of autophagy induced by S. agalactiae in bovine mammary epithelial cells (bMECs) is mainly unknown. So in this study, an intracellular S. agalactiae infection model was established. Through evaluating the autophagy-related indicators, we observed that after S. agalactiae infection, a significant quantity of LC3-I was converted to LC3-II, p62 was degraded, and levels of Beclin1 and Bcl2 increased significantly in bMECs, indicating that S. agalactiae induced autophagy. The increase in levels of LAMP2 and LysoTracker Deep Red fluorescent spots indicated that lysosomes had participated in the degradation of autophagic contents. After autophagy was activated by rapamycin (Rapa), the amount of p-Akt and p-mTOR decreased significantly, whilst the amount of intracellular S. agalactiae increased significantly. Whereas the autophagy was inhibited by 3-methyladenine (3MA), the number of intracellular pathogens decreased. In conclusion, the results demonstrated that S. agalactiae could induce autophagy through PI3K/Akt/mTOR pathway and utilize autophagy to survive in bMECs.

Broad Ultrastructural and Transcriptomic Changes Underlie the Multinucleated Giant Hemocyte Mediated Innate Immune Response against Parasitoids

Multinucleated giant hemocytes (MGHs) represent a novel type of blood cell in insects that participate in a highly efficient immune response against parasitoid wasps involving isolation and killing of the parasite. Previously, we showed that circulating MGHs have high motility and the interaction with the parasitoid rapidly triggers encapsulation. However, structural and molecular mechanisms behind these processes remained elusive. Here, we used detailed ultrastructural analysis and live cell imaging of MGHs to study encapsulation in Drosophila ananassae after parasitoid wasp infection. We found dynamic structural changes, mainly driven by the formation of diverse vesicular systems and newly developed complex intracytoplasmic membrane structures, and abundant generation of giant cell exosomes in MGHs. In addition, we used RNA sequencing to study the transcriptomic profile of MGHs and activated plasmatocytes 72 h after infection, as well as the uninduced blood cells. This revealed that differentiation of MGHs was accompanied by broad changes in gene expression. Consistent with the observed structural changes, transcripts related to vesicular function, cytoskeletal organization, and adhesion were enriched in MGHs. In addition, several orphan genes encoding for hemolysin-like proteins, pore-forming toxins of prokaryotic origin, were expressed at high level, which may be important for parasitoid elimination. Our results reveal coordinated molecular and structural changes in the course of MGH differentiation and parasitoid encapsulation, providing a mechanistic model for a powerful innate immune response.

Ultrastructural changes associated to the neuroendocrine transdifferentiation of the lung adenocarcinoma cell line A549

The neuroendocrine transdifferentiation has been found in many cancer cell types, such as prostate, lung and gastrointestinal cells and is accompanied by a lower patient life expectancy. The transdifferentiation process has been induced in vitro by the exposure to different stimuli in human lung adenocarcinoma. The aim of this work was to identify the morphological characteristics of the neuroendocrine phenotype in a human lung cancer cell line, induced by two cAMP elevating agents (IBMX and FSK). Our results showed two phenotypes, one produced by IBMX with higher volume, cell size and increased number of secondary projections, and the other produced by FSK with higher area, roughness of the membrane, cell neurite percentage, number of outgrowths per cell and increased number of primary projections. In conclusion, we describe some morphological and ultrastructural characteristics of the neuroendocrine phenotype in A549 human lung cancer cell line promoted by IBMX and FSK to contribute to the understanding of the autocrine or paracrine signaling within the tumor microenvironment.

Critical Evaluation of Different Lysosomal Labeling Methods Used to Analyze RNA Nanocarrier Trafficking in Cells

The use of nucleic acids to regulate gene expression is a rapidly developing field with immense clinical potential. Nanomaterials are frequently used to deliver nucleic acids into cells as they can overcome the poor cellular uptake and endo/lysosomal degradation of bare nucleic acids. For these nanocarriers to be effective, they must escape endo/lysosomal compartments to deliver their nucleic acid cargo into the cytosol (for ribonucleic acid (RNA)) or nucleus (for deoxyribonucleic acid (DNA)). This process is poorly understood and remains an area of active research toward the goal of developing effective delivery strategies. Fluorescent endo/lysosomal markers are among the most widely employed tools used to evaluate the endosomal escape of nucleic acid nanocarriers. However, the endo/lysosomal labeling method may alter the extent of and route of nanocarrier uptake by cells. The impact of these markers on cellular function and cell-nanocarrier interactions has not been probed in a systematic manner. To investigate this, we compared the effects of several common lysosomal labeling methods, namely, LysoTracker Red (LT Red), transient lysosomal-associated membrane protein 1-mutant green fluorescent protein (LAMP1-mGFP) transfection (Transient GFP), and stable lentiviral LAMP1-mGFP transfection (Stable GFP), on cellular metabolic activity, nanocarrier uptake, nanocarrier/lysosomal label colocalization, and gene silencing potency in U87 glioblastoma and MDA-MB-231 breast cancer cells using polyethyleneimine (PEI)/ribonucleic acid (RNA) polyplexes as a model nanocarrier. In both U87s and MDA-MB-231s, Transient GFP and LT Red labeling reduced metabolic activity relative to untransfected (Parental) cells, while Stable GFP labeling increased metabolic activity. Congruently, flow cytometry indicates Stable GFP cells have greater polyplex uptake than LT Red-labeled cells in both cell lines. Despite these similar trends in uptake, polyplex intracellular trafficking differs in the two cell lines, as confocal imaging revealed greater polyplex/lysosome colocalization in Stable GFP U87 cells than LT Red-labeled U87 cells, while the trend was reversed in MBA-MB-231s. The level of RNA-mediated gene silencing achieved in Parental versus Stable GFP U87 and MDA-MB-231 cells agreed with the observed levels of polyplex/lysosome colocalization, supporting the established concept that endosomal escape is the rate-limiting step for RNA interference. These findings indicate that lysosomal labels can profoundly alter cellular function and cell-nanocarrier interactions, presenting critical new considerations for researchers investigating nanoparticle trafficking.

Oxidative Stress Enhances Autophagy-Mediated Death Of Stem Cells Through Erk1/2 Signaling Pathway - Implications For Neurotransplantations

Stem cell therapies are becoming increasingly popular solutions for neurological disorders. However, there is a lower survival rate of these cells after transplantation. Oxidative stress is linked to brain damage, and it may also impact transplanted stem cells. To better understand how transplanted cells respond to oxidative stress, the current study used H₂O₂. We briefly illustrated that exogenous H₂O₂ treatment exaggerated oxidative stress in the human dental pulp and mesenchymal stem cells. 2',7'-Dichlorofluorescin diacetate (DCFDA), MitoSOX confirms the reactive oxygen species (ROS) involvement, which was remarkably subsided by the ROS inhibitors. The findings showed that H₂O₂ activates autophagy by enhancing pro-autophagic proteins, Beclin1 and Atg7. Increased LC3II/I expression (which co-localized with lysosomal proteins, LAMP1 and Cathepsin B) showed that H₂O₂ treatment promoted autophagolysosome formation. In the results, both Beclin1 and Atg7 were observed co-localized in mitochondria, indicating their involvement in mitophagy. The evaluation of Erk1/2 in the presence and absence of Na-Pyruvate, PEG-Catalase, and PD98059 established ROS-Erk1/2 participation in autophagy regulation. Further, these findings showed a link between apoptosis and autophagy. The results conclude that H₂O₂ acts as a stressor, promoting autophagy and mitophagy in stem cells under oxidative stress. The current study may help understand better cell survival and death approaches for transplanted cells in various neurological diseases. The current study uses human Dental Pulp and Mesenchymal Stem cells to demonstrate the importance of H₂O₂-driven autophagy in deciding the fate of these cells in an oxidative microenvironment. To summarise, we discovered that exogenous H₂O₂ treatment causes oxidative stress. Exogenous H₂O₂  treatment also increased ROS production, especially intracellular H₂O₂. H₂O₂ stimulated the ErK1/2 signaling pathway and autophagy. Erk1/2 was found to cause autophagy. Further, the function of mitophagy appeared to be an important factor in the H₂O₂-induced regulation of these two human stem cell types. In a nutshell, by engaging in autophagy nucleation, maturation, and terminal phase proteins, we elucidated the participation of autophagy in cell dysfunction and death.

Effect and molecular mechanism research of Astragalus membranaceus on inhibiting intestinal absorption of six alkaloids of Aconitum carmichaelii in spleen deficiency rats

Objective

To investigate the effect and the mechanism of Astragalus membranaceus (Huangqi in Chinese, HQ) extract on the intestinal absorption of six alkaloids of Aconitum carmichaelii (Fuzi in Chinese, FZ) in rats with spleen deficiency and provide novel insights into the application of HQ on modulating intestinal barrier.

Methods

Four-week-old male Sprague-Dawley rats were fed with Xiaochengqi Decoction to induce the spleen deficiency model for 40 d. Single-pass intestinal perfusion model were used to study the effects of HQ extract on the absorption of alkaloids. Protein expression and mRNA levels of MRP2 and BCRP and tight junction proteins (TJ, including Claudin-1, Occludin and ZO-1) were measured using Western blot and real-time PCR, respectively. The location and expression of TJ protein was also investigated by the immunofluorescence method.

Results

Compared with the normal group, the protein expression of MRP2, BCRP and TJ proteins in the model group were significantly down-regulated. After oral administration of HQ, the alkaloid absorption in intestinal villi was inhibited, MRP2, BCRP and TJ proteins were up-regulated, the green fluorescence staining of Claudin-1, Occludin, and ZO-1 was enhanced, and a thick layer of mucus was deposited on the surface of the epithelium of the intestinal cavity.

Conclusion

HQ as an intestinal barrier modulator improves the physiological changes of the intestinal environment of spleen deficiency to reduce the absorption of toxic components, leading to a decrease in the absorption of drug-like molecules.

pH-activated, mitochondria-targeted, and redox-responsive delivery of paclitaxel nanomicelles to overcome drug resistance and suppress metastasis in lung cancer

Background

Mitochondria play a role in the occurrence, development, drug resistance, metastasis, and other functions of cancer and thus are a drug target. An acid-activated mitochondria-targeting drug nanocarrier with redox-responsive function was constructed in the present study. However, whether this vector can precisely delivery paclitaxel (PTX) to enhance therapeutic efficacy in drug-resistant lung cancer is unknown.

Results

Acid-cleavable dimethylmaleic anhydride (DA) was used to modify pluronic P85-conjugated mitochondria-targeting triphenylphosphonium (TPP) using disulfide bonds as intermediate linkers (DA-P85-SS-TPP and DA-P-SS-T). The constructed nanocarriers demonstrated enhanced cellular uptake and selective mitochondrial targeting at extracellular pH characteristic for a tumor (6.5) and were characterized by extended circulation in the blood. TPP promoted the targeting of the DA-P-SS-T/PTX nanomicelles to the mitochondrial outer membrane to decrease the membrane potential and ATP level, resulting in inhibition of P-glycoprotein and suppression of drug resistance and cancer metastasis. PTX was also rapidly released in the presence of high glutathione (GSH) levels and directly diffused into the mitochondria, resulting in apoptosis of drug-resistant lung cancer cells.

Conclusions

These promising results indicated that acid-activated mitochondria-targeting and redox-responsive nanomicelles potentially represent a significant advancement in cancer treatment.

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Tuning NO release of organelle-targeted furoxan derivatives and their cytotoxicity against lung cancer cells

We herein report a study on a set of hybrid compounds in which 3-R-substituted furoxan moieties (R = CH₃, CONH₂, CN, SO₂C₆H₅), endowed with varying NO-releasing capacities, are joined to a mitochondrial probe, rhodamine B. Each product has been investigated for its ability to release NO both in physiological solution, in the presence of cysteine, and in A549 lung adenocarcinoma cancer cells. The cytotoxicity of all the products against the aforementioned cancer cells has been assessed, including the structurally related compounds with no mitochondrial targeting, which were taken as a reference. In the case of the models bearing the -CH₃ and -CONH₂ groups at the 3-position on the furoxan, only the targeted models showed a significant cytotoxic activity, and only at the highest concentrations, in accordance with their weak NO-releasing properties. On the contrary, the presence of the strong electron-withdrawing groups, as -CN and -SO₂C₆H₅, at the 3-position gave rise to anticancer agents, likely because of the high NO-releasing and of their capability of inhibiting cellular proteins by covalent binding. In detail, the rhodamine hybrid containing the 3-SO₂C₆H₅ substituted furoxan moiety emerged as the most interesting product as it showed high cytotoxicity over the entire concentration range tested. This substructure was also linked to a phenothiazine scaffold that is able to accumulate in lysosomes. Nevertheless, mitochondrial targeting for these NO-donor furoxan substructures was found to be the most efficient.

Centrosome amplification mediates small extracellular vesicle secretion via lysosome disruption

Bidirectional communication between cells and their surrounding environment is critical in both normal and pathological settings. Extracellular vesicles (EVs), which facilitate the horizontal transfer of molecules between cells, are recognized as an important constituent of cell-cell communication. In cancer, alterations in EV secretion contribute to the growth and metastasis of tumor cells. However, the mechanisms underlying these changes remain largely unknown. Here, we show that centrosome amplification is associated with and sufficient to promote small extracellular vesicle (SEV) secretion in pancreatic cancer cells. This is a direct result of lysosomal dysfunction, caused by increased reactive oxygen species (ROS) downstream of extra centrosomes. We propose that defects in lysosome function could promote multivesicular body fusion with the plasma membrane, thereby enhancing SEV secretion. Furthermore, we find that SEVs secreted in response to amplified centrosomes are functionally distinct and activate pancreatic stellate cells (PSCs). These activated PSCs promote the invasion of pancreatic cancer cells in heterotypic 3D cultures. We propose that SEVs secreted by cancer cells with amplified centrosomes influence the bidirectional communication between the tumor cells and the surrounding stroma to promote malignancy.

Luminescent Behavior of Gels and Sols Comprised of Molecular Gelators

We present a brief review of some important conceptual and practical aspects for the design and properties of molecular luminescent gelators and their gels. Topics considered include structural and dynamic aspects of the gels, including factors important to their ability to emit radiation from electronically excited states.

Drosophila Sex Peptide controls the assembly of lipid microcarriers in seminal fluid

Seminal fluid plays an essential role in promoting male reproductive success and modulating female physiology and behavior. In the fruit fly, Drosophila melanogaster, Sex Peptide (SP) is the best-characterized protein mediator of these effects. It is secreted from the paired male accessory glands (AGs), which, like the mammalian prostate and seminal vesicles, generate most of the seminal fluid contents. After mating, SP binds to spermatozoa and is retained in the female sperm storage organs. It is gradually released by proteolytic cleavage and induces several long-term postmating responses, including increased ovulation, elevated feeding, and reduced receptivity to remating, primarily signaling through the SP receptor (SPR). Here, we demonstrate a previously unsuspected SPR-independent function for SP. We show that, in the AG lumen, SP and secreted proteins with membrane-binding anchors are carried on abundant, large neutral lipid-containing microcarriers, also found in other SP-expressing Drosophila species. These microcarriers are transferred to females during mating where they rapidly disassemble. Remarkably, SP is a key microcarrier assembly and disassembly factor. Its absence leads to major changes in the seminal proteome transferred to females upon mating. Males expressing nonfunctional SP mutant proteins that affect SP's binding to and release from sperm in females also do not produce normal microcarriers, suggesting that this male-specific defect contributes to the resulting widespread abnormalities in ejaculate function. Our data therefore reveal a role for SP in formation of seminal macromolecular assemblies, which may explain the presence of SP in Drosophila species that lack the signaling functions seen in Dmelanogaster.

Physcion-8-O-β-d-glucoside interferes with the nuclear factor-κB pathway and downregulates P-glycoprotein expression to reduce paclitaxel resistance in ovarian cancer cells

OBJECTIVE

This study assessed whether physcion-8-O-beta-D-monoglucoside (PG) sensitises paclitaxel (PTX)-resistant ovarian cancer cells and explored the underlying mechanism.

METHODS

Ovarian cancer SK-OV-3 cells were used to establish PTX-resistant SK-OV-3 (SK-OV-3/PTX) cells. The Cell Counting Kit-8 assay and crystal violet staining were used to determine cell viability. P-glycoprotein (P-gp) and nuclear factor (NF)-κB expression and cell distributions were detected using immunofluorescence. Cell apoptosis and protein expression changes were detected using flow cytometry and western blotting, respectively. Effect of PG in vivo was evaluated using a xenograft tumour model. P-gp expression in tumour tissues was detected using immunohistochemical staining.

KEY FINDINGS

PG (1-10 μm) did not significantly affect SK-OV-3/PTX cell proliferation but significantly downregulated P-gp expression. PG pretreatment (1-10 μm) enhanced PTX cytotoxicity. PG treatment decreased the quantity of phosphorylated-NF-κB p65 in SK-OV-3/PTX cell total proteins and upregulated IKBα expression. Simultaneously, it decreased NF-κB p65 levels in nuclear proteins. PG (1-10 μm) inhibited NF-κB p65 entry into the nucleus. PTX plus PG significantly inhibited SK-OV-3/PTX xenograft tumour growth. PG (1-10 μm) reduced P-gp expression in transplanted tumour tissue.

CONCLUSIONS

PG can enhance the sensitivity of PTX-resistant ovarian cancer cells SK-OV-3/PTX to PTX, and this effect is related to inhibiting NF-κB from entering the nucleus and down-regulating the expression of P-gp protein.

pHLARE: a new biosensor reveals decreased lysosome pH in cancer cells

Many lysosome functions are determined by a lumenal pH of ∼5.0, including the activity of resident acid-activated hydrolases. Lysosome pH (pHlys) is often increased in neurodegenerative disorders and predicted to be decreased in cancers, making it a potential target for therapeutics to limit the progression of these diseases. Accurately measuring pHlys, however, is limited by currently used dyes that accumulate in multiple intracellular compartments and cannot be propagated in clonal cells for longitudinal studies or used for in vivo determinations. To resolve this limitation, we developed a genetically encoded ratiometric pHlys biosensor, pHLARE (pHLysosomal Activity REporter), which localizes predominantly in lysosomes, has a dynamic range of pH 4.0 to 6.5, and can be stably expressed in cells. Using pHLARE we show decreased pHlys with inhibiting activity of the mammalian target of rapamycin complex 1 (mTORC1). Also, cancer cells from different tissue origins have a lower pHlys than untransformed cells, and stably expressing oncogenic RasV12 in untransformed cells is sufficient to decrease pHlys. pHLARE is a new tool to accurately measure pHlys for improved understanding of lysosome dynamics, which is increasingly considered a therapeutic target.

Design of fluorophore-loaded human serum albumin nanoparticles for specific targeting of NIH:OVCAR3 ovarian cancer cells

Nowadays, extensive research is being carried out to find innovative solutions for the development of stable, reproductible, and highly efficient fluorescent contrast agents with the ability of targeting specific cells, which can be further implemented for fluorescent-guided surgery in a real clinical setting. The present study is focused on the development of fluorescent dye-loaded protein nanoparticles (NPs) to overcome the drawbacks of the standard administration of free organic fluorophores, such as cytotoxicity, aqueousinstability, and rapid photo-degradation. Precisely, human serum albumin (HSA) NPs loaded with two different FDA approved dyes, namely indocyanine green (ICG) and fluorescein isothiocyanate (FITC), with a fluorescence response in the near-infrared and visible spectral domains, respectively, have been successfully designed. Even though the diameter of fluorescent HSA NPs is around 30 nm as proven by dynamic light scattering and transmission electron microscopy investigations, they present good loading efficiencies of almost 50% for ICG, and over 30% for FITC and a high particle yield of over 75%. Molecular docking simulations of ICG and FITC within the structure of HSA confirmed that the dyes were loaded inside the NPs, and docked in Site I (subdomain IIA) of the HSA molecule. After the confirmation of their high fluorescence photostability, the NPs were covalently conjugated with folic acid (HSA-FA NPs) in order to bind specifically to the folate receptor alpha (FRα) protein overexpressed on NIH:OVCAR3 ovarian cancer cells. Finally, fluorescence microscopy imaging investigations validate the improved internalization of folate targeted HSA&FITC NPs compared to cells treated with untargeted ones. Furthermore, TEM examinations of the distribution of HSA NPs into the NIH:OVCAR3 cells revealed anincreased number of NP-containing vesicles for the cells treated with HSA-FA NPs, compared to the cells exposed to untargeted HAS NPs, upholding the enhanced cellular uptake through FRα-mediated potocytosis.

In vitro Biological Tests as the First Tools To Validate Magnetic Nanotheranostics for Colorectal Cancer Models

Colorectal cancer (CRC) remains a leading cause of cancer death. Nanotechnology has focused on reaching more effective treatments. In this concern, magnetic nanoparticles (MNPs) have been studied for a wide range of biomedical applications related to CRC, such as diagnostic imaging, drug delivery and thermal therapy. However, limited research is currently found in the open literature that refers to nanosystems combining all these mentioned areas (theranostics). When developing nanosystems intended as theranostics applied to CRC, possible variations between patients must be considered. Therefore, multiple in vitro assays are required as guidance for future preclinical and clinical trials. The objective of this contribution is to evaluate the available and recent literature regarding the interactions of MNP and CRC models, aiming to critically analyze the information given by the commonly used assays and evaluate the data provided by each one with a view to implementing this novel technology in CRC diagnostics and therapy.

Designer Cathinones N-Ethylhexedrone and Buphedrone Show Different In Vitro Neurotoxicity and Mice Behaviour Impairment

N-Ethylhexedrone (NEH) and buphedrone (Buph) are emerging synthetic cathinones (SC) with limited information about their detrimental effects within central nervous system. Objectives: To distinguish mice behavioural changes by NEH and Buph and validate their differential harmful impact on human neurons and microglia. In vivo safety data showed the typical induced behaviour of excitation and stereotypies with 4-64 mg/kg, described for other SC. Buph additionally produced jumping and aggressiveness signs, while NEH caused retropulsion and circling. Transient reduction in body-weight gain was obtained with NEH at 16 mg/kg and induced anxiolytic-like behaviour mainly with Buph. Both drugs generated place preference shift in mice at 4 and 16 mg/kg, suggestive of abuse potential. In addition, mice withdrawn NEH displayed behaviour suggestive of depression, not seen with Buph. When tested at 50-400 μM in human nerve cell lines, NEH and Buph caused neuronal viability loss at 100 μM, but only NEH produced similar results in microglia, indicating different cell susceptibilities. NEH mainly induced microglial late apoptosis/necrosis, while Buph caused early apoptosis. NEH was unique in triggering microglia shorter/thicker branches indicative of cell activation, and more effective in increasing microglial lysosomal biogenesis (100 μM vs. 400 μM Buph), though both produced the same effect on neurons at 400 μM. These findings indicate that NEH and Buph exert neuro-microglia toxicities by distinct mechanisms and highlight NEH as a specific inducer of microglia activation. Buph and NEH showed in vivo/in vitro neurotoxicities but enhanced specific NEH-induced behavioural and neuro-microglia dysfunctionalities pose safety concerns over that of Buph.

The SMAC mimetic LCL161 is a direct ABCB1/MDR1-ATPase activity modulator and BIRC5/Survivin expression down-regulator in cancer cells

Upregulation of ABCB1/MDR1 (P-gp) and BIRC5/Survivin promotes multidrug resistance in a variety of human cancers. LCL161 is an anti-cancer DIABLO/SMAC mimetic currently being tested in patients with solid tumors, but the molecular mechanism of action of LCL161 in cancer cells is still incompletely understood. It is still unclear whether LCL161 is therapeutically applicable for patients with ABCB1-overexpressing multidrug resistant tumors. In this study, we found that the potency of LCL161 is not affected by the expression of ABCB1 in KB-TAX50, KB-VIN10, and NTU0.017 cancer cells. Besides, LCL161 is equally potent towards the parental MCF7 breast cancer cells and its BIRC5 overexpressing, hormone therapy resistance subline MCF7-TamC3 in vitro. Mechanistically, we found that LCL161 directly modulates the ABCB1-ATPase activity and inhibits ABCB1 multi-drug efflux activity at low cytotoxic concentrations (i.e. 0.5xIC₅₀ or less). Further analysis revealed that LCL161 also decreases intracellular ATP levels in part through BIRC5 downregulation. Therapeutically, co-treatment with LCL161 at low cytotoxic concentrations restored the sensitivity to the known ABCB1 substrate, paclitaxel, in ABCB1-expressing cancer cells and increased the sensitivity to tamoxifen in MCF7-TamC3 cells. In conclusion, LCL161 has the potential for use in the management of cancer patients with ABCB1 and BIRC5-related drug resistance. The findings of our study provide important information to physicians for designing a more "patient-specific" LCL161 clinical trial program in the future.

Cell Death Effects Induced by Sulforaphane and Allyl Isothiocyanate on P-Glycoprotein Positive and Negative Variants in L1210 Cells

Variants of L1210 leukemia cells-namely, parental P-glycoprotein-negative S cells and R and T cells expressing P-glycoprotein, due to selection with vincristine and transfection with the human p-glycoprotein gene, respectively-were used. The responses of these cell variants to two naturally occurring isothiocyanates-sulforaphane (SFN, from cruciferous vegetables) and allyl isothiocyanate (AITC, from mustard, radish, horseradish and wasabi)-were studied. We obtained conflicting results for the cell death effects induced by isothiocyanates, as measured by i. cell counting, which showed inhibited proliferation, and ii. cell metabolic activity via an MTS assay, which showed an increased MTS signal. These results indicated the hyperactivation of cell metabolism induced by treatment with isothiocyanates. In more detailed study, we found that, depending on the cell variants and the isothiocyanate used in treatment, apoptosis and necrosis (detected by annexin-V cells and propidium iodide staining), as well as autophagy (detected with monodansylcadaverine), were involved in cell death. We also determined the cell levels/expression of Bcl-2 and Bax as representative anti- and pro-apoptotic proteins of the Bcl-2 family, the cell levels/expression of members of the canonical and noncanonical NF-κB pathways, and the cell levels of 16 and 18 kDa fragments of LC3B protein as markers of autophagy.

Alteration of the Mitochondrial Effects of Ceria Nanoparticles by Gold: An Approach for the Mitochondrial Modulation of Cells Based on Nanomedicine

Ceria nanoparticles are cell compatible antioxidants whose activity can be enhanced by gold deposition and by surface functionalization with positive triphenylphosphonium units to selectively target the mitochondria. The antioxidant properties of these nanoparticles can serve as the basis of a new strategy for the treatment of several disorders exhibiting oxidative stress, such as cancer, diabetes or Alzheimer’s disease. However, all of these pathologies require a specific antioxidant according with their mechanism to remove oxidant species excess in cells and diminish their effect on mitochondrial function. The mechanism through which ceria nanoparticles neutralize oxidative stress and their effect on mitochondrial function have not been characterized yet. In the present study, the mitochondria antioxidant effect of ceria and ceria-supported gold nanoparticles, with or without triphenylphosphonium functionalization, was assessed in HeLa cells. The effect caused by ceria nanoparticles on mitochondria function in terms of mitochondrial membrane potential (∆Ψm), adenosine triphosphate (ATP) production, nuclear respiratory factor 1 (NRF1) and nuclear factor erythroid–2–like 1 (NFE2L1) was reversed by the presence of gold. Furthermore, this effect was enhanced when nanoparticles were functionalized with triphenylphosphonium. Our study illustrates how the mitochondrial antioxidant effect induced by ceria nanoparticles can be modulated by the presence of gold.

Tumor- and mitochondria-targeted nanoparticles eradicate drug resistant lung cancer through mitochondrial pathway of apoptosis

Chemotherapeutic drugs frequently encounter multidrug resistance. ATP from mitochondria helps overexpression of drug efflux pumps to induce multidrug resistance, so mitochondrial delivery as a means of "repurposing'' chemotherapeutic drugs currently used in the clinic appears to be a worthwhile strategy to pursue for the development of new anti-drug-resistant cancer agents. TPP-Pluronic F127-hyaluronic acid (HA) (TPH), with a mitochondria-targeting triphenylphosphine (TPP) head group, was first synthesized through ester bond formation. Paclitaxel (PTX)-loaded TPH (TPH/PTX) nanomicelles exhibited excellent physical properties and significantly inhibited A549/ADR cells. After TPH/PTX nanomicelles entered acidic lysosomes through macropinocytosis, the positively charged TP/PTX nanomicelles that resulted from degradation of HA by hyaluronidase (HAase) in acidic lysosomes were exposed and completed lysosomal escape at 12 h, finally localizing to mitochondria over a period of 24 h in A549/ADR cells. Subsequently, TPH/PTX caused mitochondrial outer membrane permeabilization (MOMP) by inhibiting antiapoptotic Bcl-2, leading to cytochrome C release and activation of caspase-3 and caspase-9. In an A549/ADR xenograft tumor model and a drug-resistant breast cancer-bearing mouse model with lung metastasis, TPH/PTX nanomicelles exhibited obvious tumor targeting and significant antitumor efficacy. This work presents the potential of a single, nontoxic nanoparticle (NP) platform for mitochondria-targeted delivery of therapeutics for diverse drug-resistant cancers.

Lysosome imaging in cancer cells by pyrene-benzothiazolium dyes: An alternative imaging approach for LAMP-1 expression based visualization methods to avoid background interference

A series of pyrene-benzothiazolium dyes (1a-1d) were experimentally investigated to study their internalization mechanism into cellular lysosomes as well as their potential imaging applications for live cell imaging. The lysosome selectivity of the probes was further compared by using fluorescently tagged lysosome associated membrane protein-1 (LAMP-1) expression-dependent visualization in both normal (COS-7, HEK293) and cancer (A549, Huh 7.5) cell lines. These probes were successfully employed as reliable lysosome markers in tumor cell models, thus providing an attractive alternative to LAMP-1 expression-dependent visualization methods. One advantage of these probes is the elimination of significant background fluorescence arising from fluorescently tagged protein expression on the cell surface when cells were transfected with LAMP-1 expression plasmids. Probes exhibited remarkable ability to stain cellular lysosomes for long-term experiments (up to 24 h) and the highly lipophilic nature of the probe design allowed their accumulation in hydrophobic regions of the cellular lysosomes. Experimental evidences indicated that the probes are likely to be internalized into lysosomes via endocytosis and accumulated in the hydrophobic regions of the lysosomes rather than in the acidic lysosomal lumen. These probes also demonstrated significant stability and lysosome staining for fixed cell imaging applications as well. Lastly, the benzothiazolium moiety of the probes was identified as the key component for lysosome selectivity.

What sustains the multidrug resistance phenotype beyond ABC efflux transporters? Looking beyond the tip of the iceberg

Identification of multidrug (MDR) efflux transporters that belong to the ATP-Binding Cassette (ABC) superfamily, represented an important breakthrough for understanding cancer multidrug resistance (MDR) and its possible overcoming. However, recent data indicate that drug resistant cells have a complex intracellular physiology that involves constant changes in energetic and oxidative-reductive metabolic pathways, as well as in the molecular circuitries connecting mitochondria, endoplasmic reticulum (ER) and lysosomes. The aim of this review is to discuss the key molecular mechanisms of cellular reprogramming that induce and maintain MDR, beyond the presence of MDR efflux transporters. We specifically highlight how cancer cells characterized by high metabolic plasticity - i.e. cells able to shift the energy metabolism between glycolysis and oxidative phosphorylation, to survive both the normoxic and hypoxic conditions, to modify the cytosolic and mitochondrial oxidative-reductive metabolism, are more prone to adapt to exogenous stressors such as anti-cancer drugs and acquire a MDR phenotype. Similarly, we discuss how changes in mitochondria dynamics and mitophagy rates, changes in proteome stability ensuring non-oncogenic proteostatic mechanisms, changes in ubiquitin/proteasome- and autophagy/lysosome-related pathways, promote the cellular survival under stress conditions, along with the acquisition or maintenance of MDR. After dissecting the complex intracellular crosstalk that takes place during the development of MDR, we suggest that mapping the specific adaptation pathways underlying cell survival in response to stress and targeting these pathways with potent pharmacologic agents may be a new approach to enhance therapeutic efficacy against MDR tumors.

A translational approach to assess the metabolomic impact of stabilized gold nanoparticles by NMR spectroscopy

Gold nanoparticles have high potential in the biomedical area, especially in disease diagnosis and treatment. The application of these nanoparticles requires the presence of stabilizers to avoid their agglomeration. Nowadays, there is a lack of reliable methods for characterising the effect of stabilised nanoparticles on biological systems. To this end, in this study, we apply an experimental approach based on nuclear magnetic resonance spectroscopy to study the effect of gold nanoparticles, stabilised with cerium oxide or chitosan, on a human cancer cell model. The results showed that both systems have a significant effect, even at non-toxic levels, on the cellular antioxidant system. However, although particles functionalised with chitosan exerted a strong effect on the aerobic respiration, nanoparticles stabilised with cerium oxide had a higher impact on the mechanisms associated with anaerobic energy production. Therefore, even though both systems contained similar gold nanoparticles, the presence of different stabilizers strongly influenced their mode of action and potential applications in biomedicine.