A Platinum-Aluminum Bimetallic Salen Complex for Pro-senescence Cancer Therapy.

Cell senescence is defined as irreversible cell cycle arrest, which can be triggered by telomere shortening or by various types of genotoxic stress. Induction of senescence is emerging as a new strategy for the treatment of cancer, especially when sequentially combined with a second senolytic drug capable of killing the resulting senescent cells, however severely suffering from the undesired off-target side effects from the senolytic drugs. Here, we prepare a bimetalic platinum-aluminum salen complex (Alumiplatin) for cancer therapy-a combination of pro-senesence chemotherapy with in situ senotherapy to avoid the side effects. The aluminum salen moiety, as a G-quadruplex stabilizer, enhances the salen's ability to induce cancer cell senescence and this phenotype is in turn sensitive to the cytotoxic activity of the monofunctional platinum moiety. It exhibits an excellent capability for inducing senescence, a potent cytotoxic activity against cancer cells both in vitro and in vivo, and an improved safety profile compared to cisplatin. Therefore, Alumiplatin may be a good candidate to be further developed into safe and effective anticancer agents. This novel combination of cell senescence inducers with genotoxic drugs revolutionizes the therapy options of designing multi-targeting anticancer agents to improve the efficacy of anticancer therapies.

Blood-Brain Barrier-Penetrating and Lesion-Targeting Nanoplatforms Inspired by the Pathophysiological Features for Synergistic Ischemic Stroke Therapy.

Ischemic stroke is a dreadful vascular disorder that poses enormous threats to the public health. Due to its complicated pathophysiological features, current treatment options after ischemic stroke attack remains unsatisfactory. Insufficient drug delivery to ischemic lesions impeded by the blood-brain barrier (BBB) largely limits the therapeutic efficacy of most anti-stroke agents. Herein, inspired by the rapid BBB penetrability of 4T1 tumor cells upon their brain metastasis and natural roles of platelet in targeting injured vasculatures, a bio-derived nanojacket is developed by fusing 4T1 tumor cell membrane with platelet membrane, which further clothes on the surface of paeonol and polymetformin-loaded liposome to obtain biomimetic nanoplatforms (PP@PCL) for ischemic stroke treatment. The designed PP@PCL could remarkably alleviate ischemia-reperfusion injury by efficiently targeting ischemic lesion, preventing neuroinflammation, scavenging excess reactive oxygen species (ROS), reprogramming microglia phenotypes, and promoting angiogenesis due to the synergistic therapeutic mechanisms that anchor the pathophysiological characteristics of ischemic stroke. As a result, PP@PCL exerts desirable therapeutic efficacy in injured PC12 neuronal cells and rat model of ischemic stroke, which significantly attenuates neuronal apoptosis, reduces infarct volume, and recovers neurological functions, bringing new insights into exploiting promising treatment strategies for cerebral ischemic stroke management.

Identification of cucumber S-adenosylmethionine decarboxylase genes and functional analysis of CsSAMDC3 in salt tolerance.

As one of the key enzymes in the biosynthesis of polyamines, S-adenosylmethionine decarboxylase (SAMDC) plays an important role in plant stress resistance. In this study, four SAMDC genes (CsSAMDC1-4) were identified in cucumber (Cucumis sativus L.) and divided into three groups (I, II, and III) by phylogenetic analysis. Motif analysis suggested the existence of many conserved motifs, which is compatible with SAMDC protein classification. Gene structure analysis revealed that CsSAMDC2 and CsSAMDC3 in group I have no intron, which showed a similar response to salt stress by gene expression analysis. CsSAMDC3 responded differently to hormone and stress treatments, and was more susceptible to salt stress. Compared with wild-type (WT) tobacco, the activities of superoxide dismutase, peroxidase, and catalase were increased in CsSAMDC3-overexpressing tobacco under salt stress, but the content of electrolyte leakage, malondialdehyde, and hydrogen peroxide were decreased, which alleviated the inhibition of growth induced by salt stress. Under salt stress, overexpression of CsSAMDC3 in transgenic tobacco plants exhibited salt tolerance, mainly in the form of a significant increase in dry and fresh weight, the maximal quantum yield of PSII photochemistry, the net photosynthetic rate and the content of spermidine and spermine, while the content of putrescine was reduced. In addition, the expression levels of antioxidase-related coding genes (NtSOD, NtPOD, NtCAT) and PAs metabolism-related coding genes (NtSAMS, NtSPDS, NtSPMS, NtPAO) in transgentic plants was lower than WT under salt stress, which suggested that overexpression of CsSAMDC3 affected the expression of these genes. In summary, our results showed that CsSAMDC3 could be used as a potential candidate gene to improve salt tolerance of cucumber by regulating polyamine and antioxidant metabolism.

Nanomedicine for T-Cell Mediated Immunotherapy.

T-cell immunotherapy offers outstanding advantages in the treatment of various diseases, and with the selection of appropriate targets, efficient disease treatment can be achieved. T-cell immunotherapy has made great progress, but clinical results show that only a small proportion of patients can benefit from T-cell immunotherapy. The extensive mechanistic work outlines a blueprint for using T cells as a new option for immunotherapy, but also presents new challenges, including the balance between different fractions of T cells, the inherent T-cell suppression patterns in the disease microenvironment, the acquired loss of targets, and the decline of T-cell viability. The diversity, flexibility, and intelligence of nanomedicines give them great potential for enhancing T-cell immunotherapy. Here, how T-cell immunotherapy strategies can be adapted with different nanomaterials to enhance therapeutic efficacy is discussed. For two different pathological states, immunosuppression and immune activation, recent advances in nanomedicines for T-cell immunotherapy in diseases such as cancers, rheumatoid arthritis, systemic lupus erythematosus, ulcerative colitis, and diabetes are summarized. With a focus on T-cell immunotherapy, this review highlights the outstanding advantages of nanomedicines in disease treatment, and helps advance one's understanding of the use of nanotechnology to enhance T-cell immunotherapy.

CsPAO2 Improves Salt Tolerance of Cucumber through the Interaction with CsPSA3 by Affecting Photosynthesis and Polyamine Conversion.

Polyamine oxidases (PAOs) are key enzymes in polyamine metabolism and are related to the tolerance of plants to abiotic stresses. In this study, overexpression of cucumber (Cucumis sativus L.) PAO2 (CsPAO2) in Arabidopsis resulted in increased activity of the antioxidant enzyme and accelerated conversion from Put to Spd and Spm, while malondialdehyde content (MDA) and electrolyte leakage (EL) was decreased when compared with wild type, leading to enhanced plant growth under salt stress. Photosystem Ⅰ assembly 3 in cucumber (CsPSA3) was revealed as an interacting protein of CsPAO2 by screening yeast two-hybrid library combined with in vitro and in vivo methods. Then, CsPAO2 and CsPSA3 were silenced in cucumber via virus-mediated gene silencing (VIGS) with pV190 as the empty vector. Under salt stress, net photosynthetic rate (Pn) and transpiration rate (Tr) of CsPAO2-silencing plants were lower than pV190-silencing plants, and EL in root was higher than pV190-silencing plants, indicating that CsPAO2-silencing plants suffered more serious salt stress damage. However, photosynthetic parameters of CsPSA3-silencing plants were all higher than those of CsPAO2 and pV190-silencing plants, thereby enhancing the photosynthesis process. Moreover, CsPSA3 silencing reduced the EL in both leaves and roots when compared with CsPAO2-silencing plants, but the EL only in leaves was significantly lower than the other two gene-silencing plants, and conversion from Put to Spd and Spm in leaf was also promoted, suggesting that CsPSA3 interacts with CsPAO2 in leaves to participate in the regulation of salt tolerance through photosynthesis and polyamine conversion.

Bioinspired Design of seco-Chlorin Photosensitizers to Overcome Phototoxic Effects in Photodynamic Therapy.

Photodynamic therapy (PDT) is a non-invasive treatment modality against a range of cancers and nonmalignant diseases, however one must be aware of the risk of causing phototoxic reactions after treatment. We herein report a bioinspired design of next-generation photosensitizers (PSs) that not only effectively produce ROS but undergo fast metabolism after treatment to overcome undesirable side effects. We constructed a series of ß-pyrrolic ring-opening seco-chlorins, termed beidaphyrin (BP), beidapholactone (BPL), and their zinc(II) derivatives (ZnBP and ZnBPL), featuring intense near-infrared absorption and effective O2 photosensitization. Irradiation of ZnBPL led to a non-cytotoxic, metabolizable beidaphodiacetamide (ZnBPD) via in situ generated O2.- but not 1 O2 , as revealed by mechanistic studies including time-resolved absorption, kinetics, and isotope labeling. Furthermore, water-soluble ZnBPL showed an effective therapeutic outcome, fast metabolism, and negligible phototoxic reactions.

Nonaromatic Organonickel(II) Phototheranostics.

Earth-abundant metal-based theranostics, agents that integrate diagnostic and therapeutic functions within the same molecule, may hold the key to the development of low-cost personalized medicines. Here, we report a set of O-linked nonaromatic benzitripyrrin (C^N^N^N) macrocyclic organonickel(II) complexes, Ni-1-4, containing strong σ-donating M-C bonds. Complexes Ni-1-4 are characterized by a square-planar coordination geometry as inferred from the structural studies of Ni-1. They integrate photothermal therapy, photothermal imaging, and photoacoustic imaging (PAI) within one system. This makes them attractive as potential phototheranostics. Relative to traditional Ni(II) porphyrins, such as F20TPP (tetrapentafluorophenylporphyrin), the lowest energy absorption of Ni-1 is shifted into the near infrared region, presumably as a consequence of Ni-C bonding. Ultrafast transient absorption spectroscopy combined with theoretical calculations revealed that, upon photoexcitation, a higher population of ligand-centered and 3MLCT states is seen in Ni-1 relative to NiTPBP (TPBP = 6,11,16,21-tetraphenylbenziporphyrin). Encapsulating Ni-1 in 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG2000) afforded nanoparticles, Ni-1@DSPE, displaying red-shifted absorption features, as well as good photothermal conversion efficiency (∼45%) in aqueous media. Proof-of-principle experiments involving thrombus treatment were carried out both in vitro and in vivo. It was found that Ni-1@DSPE in combination with 785 nm photo-irradiation for 3 min (0.3 W/cm2) proved successful in removing blood clots from a mouse thrombus model as monitored by photoacoustic imaging (PAI). The present work highlights the promise of organonickel(II) complexes as potential theranostics and the benefits that can accrue from manipulating the excited-state features of early transition-metal complexes via, for example, interrupting π-conjugation pathways.

Metal Modulation: An Easy-to-Implement Tactic for Tuning Lanthanide Phototheranostics.

Phototheranostics constitute an emerging cancer treatment wherein the core diagnostic and therapeutic functions are integrated into a single photosensitizer (PS). Achieving the full potential of this modality requires being able to tune the photosensitizing properties of the PS in question. Structural modification of the organic framework represents a time-honored strategy for tuning the photophysical features of a given PS system. Here we report an easy-to-implement metal selection approach that allows for fine-tuning of excited-state energy dissipation and phototheranostics functions as exemplified by a set of lanthanide (Ln = Gd, Yb, Er) carbazole-containing porphyrinoid complexes. Femto- and nanosecond time-resolved spectroscopic studies, in conjunction with density functional theory calculations, revealed that the energy dissipation pathways for this set of PSs are highly dependent on the energy gap between the lowest triplet excited state of the ligand and the excited states of the coordinated Ln ions. The Yb complex displayed a balance of deactivation mechanisms that made it attractive as a potential combined photoacoustic imaging and photothermal/photodynamic therapy agent. It was encapsulated into mesoporous silica nanoparticles (MSN) to provide a biocompatible construct, YbL@MSN, which displays a high photothermal conversion efficiency (η = 45%) and a decent singlet oxygen quantum yield (ΦΔ = 31%). Mouse model studies revealed that YbL@MSN allows for both photoacoustic imaging and synergistic photothermal- and photodynamic-therapy-based tumor reduction in vivo. Our results lead us to suggest that metal selection represents a promising approach to fine-tuning the excited state properties and functional features of phototheranostics.

Multipolar Porphyrin-Triazatruxene Arrays for Two-Photon Fluorescence Cell Imaging.

Two-photon excited fluorescent (TPEF) materials are highly desirable for bioimaging applications owing to their unique characteristics of deep-tissue penetration and high spatiotemporal resolution. Herein, by connecting one, two, or three electron-deficient zinc porphyrin units to an electron-rich triazatruxene core via ethynyl π-bridges, conjugated multipolar molecules TAT-(ZnP)n (n=1-3) were developed as TPEF materials for cell imaging. The three new dyes present high fluorescence quantum yields (0.40-0.47) and rationally improved two-photon absorption (TPA) properties. In particular, the peak TPA cross section of TAT-ZnP (436 GM) is significantly larger than that of the ZnP reference (59 GM). The δTPA values of TAT-(ZnP)2 and TAT-(ZnP)3 further increase to 1031 and up to 1496 GM, respectively, indicating the effect of incorporated ZnP units on the TPA properties. The substantial improvement of the TPEF properties is attributed to the formation of π-conjugated quadrapole/octupole molecules and the extension of D-π-A-D systems, which has been rationalized by density function theory (DFT) calculations. Moreover, all of the three new dyes display good biocompatibility and preferential targeting ability toward cytomembrane, thus can be superior candidates for TPEF imaging of living cells. Overall, this work demonstrated a promising strategy for the development of porphyrin-based TPEF materials by the construction and extension of D-π-A-D multipolar array.

Two-Photon Excited FRET Dyads for Lysosome-Targeted Imaging and Photodynamic Therapy.

Two-photon excitable fluorescent dyes with integrated functions of targeted imaging and photodynamic therapy (PDT) are highly desired for the development of cancer theranostic agents. Herein, fluorescence resonance energy transfer (FRET) dyads, AceDAN-H2Por-Lyso (1a) and AceDAN-ZnPor-Lyso (1b), were developed for two-photon excited (TPE) lysosome-targeted fluorescence imaging and PDT of cancer cells. Under one-photon or two-photon excitation, the AceDAN donor can effectively transfer the excited state energy to the porphyrin acceptor via high efficient FRET, leading to the generation of deep-red fluorescence and singlet oxygen for cell imaging and PDT, respectively. 1a and 1b exhibit high photocytotoxicity and low dark cytotoxicity, in addition to strong lysosomal targeting capability in living cells. By taking the advantages of the two-photon absorption properties of the AceDAN donor and the properly distributed S1 and T1 states of the porphyrin acceptor, the AceDAN-porphyrin dyads 1a and 1b have been successfully applied to TPE-fluorescence imaging for tracking the significant morphology changes of cancer cells under two-photon laser irradiation.

Lysosome-targeting ratiometric fluorescent pH probes based on long-wavelength BODIPY.

BODIPY-based probes were developed for the ratiometric fluorescence detection of pH values. They showed high sensitivity under acidic conditions via a protonation-modulated ICT mechanism and could selectively stain lysosomes, and thus could be applied for imaging and detecting abnormal pH decreases in live cells.

Ratiometric Fluorescent Detection of Pb2+ by FRET-Based Phthalocyanine-Porphyrin Dyads.

Sensitive and selective detection of Pb2+ is a very worthwhile endeavor in terms of both human health and environmental protection, as the heavy metal is fairly ubiquitous and highly toxic. In this study, we designed phthalocyanine-porphyrin (Pc-Por) heterodyads, namely, H2Pc-α-ZnPor (1) and H2Pc-ß-ZnPor (2), by connecting a zinc(II) porphyrin moiety to the nonperipheral (α) or peripheral (ß) position of a metal-free phthalocyanine moiety. Upon excitation at the porphyrin Soret region (420 nm), both of the dyads exhibited not only a porphyrin emission (605 nm) but also a phthalocyanine emission (ca. 700 nm), indicating the occurrence of intramolecular fluorescence resonance energy transfer (FRET) processes from the porphyrin donor to the phthalocyanine acceptor. The dyads can selectively bind Pb2+ in the phthalocyanine core leading to a red shift of the phthalocyanine absorption and thus a decrease of spectral overlap between the porphyrin emission and phthalocyanine absorption, which in turn suppresses the intramolecular FRET. In addition, the binding of Pb2+ can highly quench the emission of phthalocyanine by heavy-metal ion effects. The synergistic coupled functions endow the dyads with remarkable ratiometric fluorescent responses at two distinct wavelengths (F605/F703 for 1 and F605/F700 for 2). The emission intensity ratio increased as a linear function to the concentration of Pb2+ in the range of 0-4.0 µM, whereas the detection limits were determined to be 3.4 × 10-9 and 2.2 × 10-8 M for 1 and 2, respectively. Furthermore, by comparative study of 1 and 2, the effects of distance and relative orientation between Pc and ZnPor fluorophores on the FRET efficiency and sensing performance were highlighted, which is helpful for further optimizing such FRET systems.

Screening hybridomas for anabolic androgenic steroids by steroid analog antigen microarray.

BACKGROUND: Currently, dozens of anabolic androgenic steroids (AAS) are forbidden in the World Anti-Doping Agency Prohibited List, however, despite extensive investigation, there are still lots of AAS without corresponding monoclonal antibodies. RESULTS: A steroid analog antigen microarray made up of ten AAS was fabricated to screen the hybridoma and it was found an original unsuccessful clone turned out to be a candidate anti-boldenone antibody, without any cross-reactions with endogenous AAS or 44 different AAS standard reference materials tested. CONCLUSION: Our findings suggested that steroid analog antigen microarray could be a promising tool to screen and characterize new applications of antibodies for structure analogs, and this also exhibits the potential to fast identify effective epitopes of hybridomas in a single assay.

Synergistic coupling of fluorescent "turn-off" with spectral overlap modulated FRET for ratiometric Ag+ sensor.

A useful strategy for ratiometric fluorescent detecting of Ag(+) is demonstrated. Upon selective binding of Ag(+) to a BODIPY-porphyrin dyad (1), the synergistic coupling of two functions, namely the suppressing of FRET from BODIPY donor to porphyrin acceptor and the fluorescence quenching of porphyrin acceptor, leads to exceptionally large changes in the intensity ratio of two distinct emissions (F513/F654) which allow for the ratiometric detecting of Ag(+) with excellent sensitivity in solution and living cells.

[Study on transport mechanism of baicalin in Scutellariae radix extracts and effect of Angelica dahurica extracts on transport of baicalin by Caco-2 cell monolayer model].

OBJECTIVE: To study the transport mechanism of baicalin of Scutellariae Radix extracts and the effect of Angelica dahurica extracts on the intestinal absorption of baicalin by using Caco-2 cell monolayer model, in order to analyze the effect mechanism of Angelica dahurica extracts on the intestinal absorption of baicalin. METHOD: The Caco-2 cell monolayer model was established with human colonic adenocarcinoma cells, and used to study the effect of pH, time, drug concentration and temperature on the transport of baicalin in Scutellariae Radix extracts, the effect of P-gp and MRP protein-dedicated inhibitors on the bidirectional transport of baicalin in Caco-2 cell model, and the effect of angelica root extracts on baicalin absorption and transport. RESULT: Baicalin was absorbed well at 37 degrees C and under pH 7.4 condition and concentration dependent. Its proteins became inactive at 4 degrees C, with a low transport. The bi-drectional transfer PDR was 0. 54. After P-gp inhibitor verapamil and MRP inhibitor probenecid were added, the value of PappBL-AP of baicalin decreased, but without any difference in PDR. The transport of baicalin was improved by 2.34, 3.31 and 3.13 times, after A. dahurica extract coumarin, volatile oil, and mixture of coumarin and volatile oil. CONCLUSION: The transport mechanism of baicalin is mainly passive transfer and supplemented with efflux proteins involved. A. dahurica extracts can enhance the absorption of baicalin, which may be related to the passive transfer merchanism of baicalin. A. dahurica extracts' effect in opening the close junction among cells may be related to its expression or function in inhibiting efflux proteins.

Elucidation of the transport mechanism of baicalin and the influence of a Radix Angelicae Dahuricae extract on the absorption of baicalin in a Caco-2 cell monolayer model.

ETHNOPHARMACOLOGICAL RELEVANCE: Angelicae Dahurica (Hoffm.) Benth. & Hook. f. ex Franch. & Sav combined with Radix Scutellariae baicalensis Georgi has been widely used in traditional Chinese medicine (TCM) as an antipyretic analgesic and anti-inflammatory drug. Modern pharmacological studies have demonstrated that the compatible application of these two drugs is an effective treatment for hepatitis. A previous study indicated that a Radix Angelicae Dahuricae extract enhanced the intestinal absorption of the baicalin found in Radix Scutellariae; however, the underlying compatibility mechanism of these two herbs remains unknown. In this study, we further examined the effect of a Radix Angelicae Dahuricae extract on the absorption and transport properties of baicalin in a Caco-2 cell model to determine the compatibility mechanism of these two herbs. AIM OF THE STUDY: The aim of this work was to study the transport properties of baicalin in Radix Scutellariae across cell membranes and the effects of a Radix Angelicae Dahuricae extract on baicalin absorption using the well-characterized, human-based intestinal Caco-2 cell model. MATERIALS AND METHODS: We assessed the absorption, bidirectional transport and toxicity of baicalin using a range of parameters, including drug concentration, pH, a P-glycoprotein (P-gp) inhibitor (Verapamil), an MRP inhibitor (MK-571) and EDTA-Na2 (tight junction modulator). Next, we studied the influence of a Radix Angelicae Dahuricae extract on the transport of baicalin under the same conditions. Drug concentration was measured by HPLC, and the apparent permeability coefficient (Papp) and apparent permeability ratio (PDR) were subsequently calculated. RESULTS: The results showed that baicalin is non-toxic within a concentration range of 800 µg/mL to 4800 µg/mL. The transport of baicalin showed time and concentration dependence. The absorption of baicalin was optimal at pH 7.4 in 37 °C; however, the absorption decreased at 4 °C. The Papp of baicalin transport through the Caco-2 cell monolayer model was altered when specific inhibitors of P-gp or MRP were added to the cells. However, there was no significant difference in the PDR value. The Papp of baicalin improved when it was combined with the Radix Angelicae Dahuricae extract. The influence of EDTA-Na2 on the transport of baicalin showed that the permeability of baicalin significantly increased. The result further indicated that the mechanism of baicalin intestinal absorption in the Caco-2 cell monolayer involves passive transcellular diffusion. CONCLUSIONS: Passive diffusion is the main mode of intestinal absorption of bacalin and it involved in the efflux of proteins. The enhanced intestinal absorption of baicalin by Radix Angelicae Dahuricae can be due to opening of the tight junctions between cells and inhibition of MRP efflux protein expression or function.

Stereochemistry and solid-state structure of an intrinsically chiral meso-patterned porphyrin: case study by NMR and single-crystal X-ray diffraction analysis.

A C1-symmerical meso-substituted ABCD-type porphyrin, [5-phenyl-10-(2-hydroxynaphthyl)-15-(4-hydroxyphenyl)porphyrinato]zinc(II) (1), has been synthesized and characterized. The molecular structure of 1 has been determined by single-crystal X-ray diffraction analysis. The complex 1 crystallizes in a triclinic system with one pair of enantiomeric molecules per unit cell. Resolution of the racemic mixture has been achieved by chiral HPLC techniques. In particular, the absolute configurations of the enantiomers have been assigned from NMR spectroscopic analysis with L-Phe-OMe as the chiral solvating agent (CSA). The assignments have also been unambiguously confirmed by single-crystal X-ray diffraction analysis. The present results suggest that the CSA-NMR anisotropy strategy is applicable for the stereochemistry determination of chiral host-guest complexes with multiple intermolecular interactions. In addition, the multiple intermolecular interactions between the enantiomerically pure porphyrin S-1 and L-Phe-OMe are proved in the solid state by single-crystal X-ray diffraction analysis.