Combination Therapy and Dual-Target Inhibitors Based on LSD1: New Emerging Tools in Cancer Therapy.

Lysine specific demethylase 1 (LSD1), a transcriptional modulator that represses or activates target gene expression, is overexpressed in many cancer and causes imbalance in the expression of normal gene networks. Over two decades, numerous LSD1 inhibitors have been reported, especially some of which have entered clinical trials, including eight irreversible inhibitors (TCP, ORY-1001, GSK-2879552, INCB059872, IMG-7289, ORY-2001, TAK-418, and LH-1802) and two reversible inhibitors (CC-90011 and SP-2577). Most clinical LSD1 inhibitors demonstrated enhanced efficacy in combination with other agents. LSD1 multitarget inhibitors have also been reported, exampled by clinical dual LSD1/histone deacetylases (HDACs) inhibitors 4SC-202 and JBI-802. Herein, we present a comprehensive overview of the combination of LSD1 inhibitors with various antitumor agents, as well as LSD1 multitarget inhibitors. Additionally, the challenges and future research directionsare also discussed, and we hope this review will provide new insight into the development of LSD1-targeted anticancer agents.

Single-Molecule Monitoring of Membrane Association of the Necroptosis Executioner MLKL with Discernible Anchoring and Insertion Dynamics.

The dynamics of membrane proteins that are well-folded in water and become functional after self-insertion into cell membranes is not well understood. Herein we report on single-molecule monitoring of membrane association dynamics of the necroptosis executioner MLKL. We observed that, upon landing, the N-terminal region (NTR) of MLKL anchors onto the surface with an oblique angle and then is immersed in the membrane. The anchoring end does not insert into the membrane, but the opposite end does. The protein is not static, switching slowly between water-exposed and membrane-embedded conformations. The results suggest a mechanism for the activation and function of MLKL in which exposure of H4 is critical for MLKL to adsorb on the membrane, and the brace helix H6 regulates MLKL rather than inhibits it. Our findings provide deeper insights into membrane association and function regulation of MLKL and would have impacts on biotechnological applications.

Engineering a HER2-CAR-NK Cell Secreting Soluble Programmed Cell Death Protein with Superior Antitumor Efficacy.

A new therapy strategy for relapsing patients who have received trastuzumab treatment urgently needs to be explored. HER2-specific chimeric antigen receptor (CAR)-expressing NK cells are being rapidly developed for solid tumor therapy, as they have many advantages over HER2-CAR-T cells. Endogenous soluble PD-1 (sPD-1) from the PD-1 extracellular domain blocks PD-1/PD-L1 interaction to promote cancer immunology. Herein, we engineered a new HER2-CAR-NK cell that co-expresses sPD-1 (designed as sPD-1-CAR-NK cells) and assessed its cytotoxic activities toward various cancer cells, activation of immunity and sPD-1 release in vitro and in mouse models bearing breast cancer cells with high HER2 expression, with or without trastuzumab resistance. We demonstrated that sPD-1-CAR-NK cells were able to release bioactive sPD-1, thereby enhancing the cytolytic activities of HER2-CAR-NK cells against HER2 and PD-L1 highly expressing target cells accompanied by increases in the secretion of perforin, granzyme B and IFN-γ. In vivo, sPD-1-CAR-NK cells had superior immunological anticancer efficacy compared to HER2-CAR-NK cells, and they had advantages over HER2-CAR-NK cells in the intraperitoneal injection of sPD-1. Moreover, the infiltration and activation of NK and T cells into tumor tissue were increased in mice with sPD-1-CAR-NK cells. There was no significant change in the body temperature, organ tissue and body weight in all groups except for the group with the PD-1 injection. Together, these data indicate that HER2-specific sPD-1-CAR-NK cells can transport sPD-1 into cancer tissues with high HER2 expression, further improving the efficacy of HER-CAR-NK cells without obvious side effects. sPD-1-CAR-NK is a promising cytotherapeutic agent for patients bearing HER2-positive breast cancer, including those with trastuzumab resistance.

Detailed curriculum vitae of HER2-targeted therapy.

With the booming development of precision medicine, molecular targeted therapy has been widely used in clinical oncology treatment due to a smaller number of side effects and its superior accuracy compared to that of traditional strategies. Among them, human epidermal growth factor receptor 2 (HER2)-targeted therapy has attracted considerable attention and has been used in the clinical treatment of breast and gastric cancer. Despite excellent clinical effects, HER2-targeted therapy remains in its infancy due to its resulting inherent and acquired resistance. Here, a comprehensive overview of HER2 in numerous cancers is presented, including its biological role, involved signaling pathways, and the status of HER2-targeted therapy.

Substituted Ti(IV) in Ce-UiO-66-NH2 Metal-Organic Frameworks Increases H2 and O2 Evolution under Visible Light.

Metal-organic frameworks (MOFs) as photocatalysts have received increasing attention. In this work, a dual metal-substituted UiO-66-NH2 (Ti/Ce-MOF) containing different Ti/Ce mole ratios (x = 0-2.46) has been prepared via post-synthetic exchange between Ce-UiO-66 and TiCl4, followed by amination. The solid had a high surface area (828-937 m2/g) and a large pore volume (0.451-0.507 m3/g). Under visible light, Ti/Ce-MOF showed x-dependent activity for H2O reduction and oxidation on a film electrode, respectively. However, such a change for H2 evolution in a Na2S/Na2SO3 aqueous solution was observed only after CdS loading. In combination with the photoluminescence and band parameters, we propose that the photoactivity of Ti/Ce-MOF for redox reaction is determined by its ability for electron transfer. Furthermore, there is an interfacial electron transfer from Ti/Ce-MOF to CdS and a hole transfer from CdS to Ti/Ce-MOF, respectively, significantly improving the efficiency of charge separation for redox reactions. This work offers a new insight that Ti substitution benefits the performance of Ce-based MOF.

Micro/nano-topography promotes osteogenic differentiation of bone marrow stem cells by regulating periostin expression.

Micro/nano-topography (MNT) is an important factor affecting cell response. Earlier studies using titania (TiO2) nanotube as a model of MNT found that they mediated the differentiation of BMSCs into osteoblasts, but the mechanisms are not fully understood. Surprisingly, Periostin (Postn), a secreted protein involved in extracellular matrix (ECM) construction and promoting osteogenic differentiation of bone marrow stem cells (BMSCs), was previously observed to significantly up-regulated on TiO2 nanotube. We proposed that Postn may act as a MNT signal transduction role. In this study, we investigated the effect of MNT on Postn, and the influence of Postn on osteogenic differentiation-related genes through focal adhesion and downstream signals. It was found that, titanium (Ti) plates carrying TiO2 nanotubes with diameters of ∼100 nm (TNT-100) significantly up-regulated the expression of Postn compared with flat Ti. Furthermore, Postn activated the downstream focal adhesion kinase (FAK) signal pathway and ß-catenin into the nucleus by interacting with integrin αV. Surprisingly, TNT-100 up-regulated the transcription level of Wnt3a, which was independent of the up-regulation of Postn. This new Postn signaling pathway may provide more insights into the signal transduction mechanism of MNT and development of biomaterials with improved osteogenic properties.

An automated streamlined method for the therapeutic drug monitoring of digoxin based on the online-solid-phase extraction liquid chromatography tandem high-resolution mass spectrometry.

RATIONALE: Digoxin is widely used in the clinical treatment of cardiovascular diseases. However, due to its extremely narrow therapeutic window, therapeutic drug monitoring (TDM) is vitally important. In consideration of the time-consuming and labor-intensive nature of the traditional techniques, an automated and efficient method was required for the clinical individualized TDM of digoxin. METHODS: An online solid-phase extraction liquid chromatography tandem high-resolution mass spectrometry (online-SPE-LC-HRMS) method was developed and applied for the determination of digoxin in plasma. The online SPE-LC steps included pretreatment and separation of plasma samples that were carried out using a Waters Oasis HLB cartridge and XBridge Shield RP18 column, respectively. A high-resolution Q Orbitrap mass spectrometer with targeted-selected ion monitoring in negative scan mode was applied to monitor formate-adduct ions [M + HCOO]- m/z 825.42781 for digoxin. RESULTS: Linearity was shown over the range 0.1-10 ng mL-1 for digoxin with correlation coefficients of R2 > 0.999. The lower limit of quantitation (LLOQ) for digoxin was 0.1 ng mL-1 . Extraction recoveries ranged from 82.61% to 94.28% for digoxin. The intra- and inter-day precision values were < 5.53% with accuracy ranging from 84.97% to 96.75%. The total running time was 10 min for each sample. CONCLUSION: The established method displayed satisfactory recoveries, accuracy, precision, and stability, and successfully applied on the TDM of digoxin. This automated streamlined method provides a powerful tool to guide the individualized administration of digoxin, which is significant for the practice of precision medicine.

Increased production of H2 under visible light by packing CdS in a Ti, Zr-Based metal organic framework.

Metal organic frameworks (MOFs) are crystalline porous materials, and some of them have been used as photocatalysts for H2 production in the presence of Pt and sacrificial reagents. Herein we report a significantly enhanced production of H2 on mixed CdS and MOF, measured under a 420 nm LED lamp in a N2-saturated aqueous solution containing Na2S and Na2SO3. MIL-125-NH2, UiO-66-NH2, and PCN-415-NH2, which are Ti-, Zr-, and Ti, Zr-based MOFs, respectively, were prepared, followed by a two-step precipitation of CdS. All MOFs were nearly not active, but CdS-loaded MOFs were not only active, but also more active than either CdS or Pt/CdS. Moreover, at 40% CdS loading, the MOF activity was PCN-415-NH2 > MIL-125-NH2 > UiO-66-NH2. N2 adsorption showed that CdS nanoparticles were present in the micropores of MOFs. Then the solid photoluminescence, band parameters, and (photo)electrochemical reactions were measured. Accordingly, a possible mechanism is proposed, involving the electron transfer from CdS to PCN-415-NH2, and the hole transfer from PCN-415-NH2 to CdS. In the reaction process, both CdS and MOF act as photocatalysts, other than co-catalysts. This work shows a simply strategy for enhancing H2 production under visible light.

Real-time imaging of structure and dynamics of transmembrane biomolecules by FRET-induced single-molecule fluorescence attenuation.

Tracking the transmembrane topology and conformational dynamics of membrane proteins is key to understand their functions. It is however challenging to monitor position changes of individual proteins in cell membranes with high sensitivity and high resolution. We review on three single-molecule fluorescence imaging methods - SIFA, LipoFRET and QueenFRET - recently developed in our lab for studying the dynamics of membrane proteins. They can be applied, progressively, to investigate membrane proteins in solid-supported lipid bilayers, artificial liposome membranes and live-cell plasma membranes. The techniques take advantage of the energy transfer from a fluorophore to a cloud of quenchers and are able to extract in real time positions and position changes of a single fluorophore-labeled protein in the direction normal to the membrane surface. The methods have sub-nanometer precision and have proved powerful to investigate biomolecules interacting with bio-membranes.

Subnanometer-Precision Measurements of Transmembrane Motions of Biomolecules in Plasma Membranes Using Quenchers in Extracellular Environment.

Characterization of biomolecular dynamics at cellular membranes lags far behind that in solutions because of challenges to measure transmembrane trafficking with subnanometer precision. Herein, by introducing nonfluorescent quenchers into extracellular environment of live cells, we adopted Förster resonance energy transfer from one donor to multiple quenchers to measure positional changes of biomolecules in plasma membranes. We demonstrated the method by monitoring flip-flops of individual lipids and by capturing transient states of the host defense peptide LL-37 in plasma membranes. The method was also applied to investigate the interaction of the necroptosis-associated protein MLKL with plasma membranes, showing a few distinct depths of MLKL insertion. Our method is especially powerful to quantitate the dynamics of proteins at the cytosolic leaflets of plasma membranes which are usually not accessible by conventional techniques. The method will find wide applications in the systematic analysis of fundamental cellular processes at plasma membranes.

The response of host blood vessels to graded distribution of macro-pores size in the process of ectopic osteogenesis.

Angiogenesis is of great importance to bone regeneration, but it remains a significant challenge to induce sufficient angiogenesis and osteogenesis within bone grafts for large bone defect healing. The aim of this study is to investigate the effects of hydroxyapatite (HA) scaffold via a novel graded pore distribution approach on vascularization and osteoinduction. Two types of graded porous scaffolds were fabricated by sugar templates-leaching techniques: (1) one with large pores of 1100-1250 µm in the center and small pores of 500-650 µm at the periphery (HALS); (2) the other with small pores of 500-650 µm in the center and large pores of 1100-1250 µm at the periphery (HASL). In vivo data showed different pore size distribution had a remarkable impact on blood vessel formation during bone formation, which led to distinct localization of new bone within the defects. After one month of implantation, the diameters of the blood vessels infiltrated on the periphery of HASL were substantially larger than those in the center though the host blood vessels were successful in infiltrating throughout the whole scaffold. In contrast, vascularization within HALS appeared to be poor with very few blood vessels formed in the center, indicating heterogeneous vascularization in the scaffolds. After 3 months of implantation, we found that HASL induced more homogeneous bone formation in the whole bone graft but new bone was only found at the periphery of HALS. This study suggests that the pores size distribution in graded scaffolds cannot only affected early stage vascularization, but also influence late stage bone formation and remodeling. The architecture of larger pores at the periphery of graded scaffold may be capable of enhancing angiogenesis and osteogenesis during large size bone defect healing.

Selective nucleation of ice crystals depending on the inclination angle of nanostructures.

Heterogeneous nucleation is decided by many factors, and surface morphology is one of the most important elements. This paper reports the selective ice nucleation and growth process on a series of nanorods with different inclinations, which were rarely mentioned in previous research studies. It is found that the nanorods with special inclinations can cause the selective nucleation of ice crystals because of the spatial geometry matching. On this basis, we can regulate the ice crystal types (mainly including cubic ice and hexagonal ice) accordingly and even improve the freezing efficiency via controlling the inclinations of surface nanorods. In particular, cubic ice occupies the dominant role in the ice crystal on the surface of 45°-inclination nanorods, yet 90°-inclination nanorods are more beneficial for the formation of hexagonal ice. The shape of the nanorods not only controls the type of ice crystal, but also changes the freezing efficiency because different ice crystals have an unequal nucleation energy barrier. There are no apparent differences in the freezing efficiency on nanostructures with 45°, 75° and 90° inclination nanorods, and 60°-inclination nanorods are more favorable for ice nucleation. Our studies can promote the understanding on the selective nucleation of ice crystals and provide a theoretical basis for achieving the regulation of freezing efficiency.

AMOT130/YAP pathway in topography-induced BMSC osteoblastic differentiation.

Micro/nano-topography (MNT) is an important variable affecting osseointegration of bone biomaterials, but the underlying mechanisms are not fully understood. We probed the role of a AMOT130/YAP pathway in osteoblastic differentiation of bone marrow mesenchymal stems cultured on titanium (Ti) carrying MNTs. Ti surfaces with two well-defined MNTs (TiO2 nanotubes of different diameters and wall thicknesses) were prepared by anodization. Rat BMSCs were cultured on flat Ti and Ti surfaces carrying MNTs, and cell behaviors (i.e., morphology, F-actin development, osteoblastic differentiation, YAP localization) were studied. Ti surfaces carrying MNTs increased F-actin formation, osteoblastic gene expression, and protein AMOT130 production in BMSCs (all vs. flat Ti), and the surface carrying larger nantubes was more effective, confirming osteoblastic differentiation induced by MNTs. Elevation of the AMOT130 level (by inhibiting its degradation) increased the osteoblastic gene expression, F-actin formation, and nuclear localization of YAP. These show that, AMOT130/YAP is an important pathway mediating the translation of MNT signals to BMSC osteoblastic commitment, likely via the cascade: AMOT130 promotion of F-actin formation, increased YAP nuclear import, and activation of osteoblastic gene expression.

Detecting Single-Molecule Dynamics on Lipid Membranes with Quenchers-in-a-Liposome FRET.

Tracking membrane-interacting molecules and visualizing their conformational dynamics are key to understanding their functions. It is, however, challenging to accurately probe the positions of a molecule relative to a membrane. Herein, a single-molecule method, termed LipoFRET, is reported to assess interplay between molecules and liposomes. It takes advantage of FRET between a single fluorophore attached to a biomolecule and many quenchers in a liposome. This method was used to characterize interactions between α-synuclein (α-syn) and membranes. These results revealed that the N-terminus of α-syn inserts into the membrane and spontaneously transitions between different depths. In contrast, the C-terminal tail of α-syn is regulated by calcium ions and floats in solution in two conformations. LipoFRET is a powerful tool to investigate membrane-interacting biomolecules with sub-nanometer precision at the single-molecule level.

Cation Channel Transient Receptor Potential Vanilloid 4 Mediates Topography-Induced Osteoblastic Differentiation of Bone Marrow Stem Cells.

Micro/nanotopographies (MNTs) have been reported to enhance the osseointegration of biomaterials and modulate cell functions, but the underlying mechanisms are incompletely understood. We hypothesized that transient receptor potential vanilloid 4 (TRPV4) may mediate the topographically induced osteoblastic differentiation of bone marrow stem cells (BMSCs) by regulating the NFATc1 and Wnt/ß-catenin signaling. To test this hypothesis, murine BMSCs were cultured on polished titanium (Ti) discs (PT) and Ti discs carrying titania nanotubes (i.e., MNTs) with diameters of ∼30 and ∼100 nm (termed TNT-30 and TNT-100, respectively). It was found that the MNTs (in particular TNT-100) promoted the expression and activation of TRPV4. Inhibition of TRPV4 in BMSCs cultured on TNT-100 reduced the expression of osteoblastic genes and the gene expression and protein levels of NFATc1 and Wnt3a/ß-catenin and also decreased nuclear translocation of NFATc1 and ß-catenin (all vs uninhibited BMSCs). Conversely, activation of TRPV4 in BMSCs cultured on PT increased the expression of the osteoblastic gene and the gene expression and protein level of NFATc1 and Wnt3a/ß-catenin and also enhanced the nuclear translocation of NFATc1 and ß-catenin (all vs unactivated BMSCs). These differences suggest that the MNTs promoted TRPV4 expression and activation to enhance intracellular Ca2+, which further increased the nuclear translocation of NFATc1 and stimulated the Wnt/ß-catenin signaling, thus leading to upregulated expression of osteoblastic genes. These results indicate TRPV4 to be a mediator in MNT-induced osteoblastic differentiation of BMSCs.