Sophflarine A, a novel matrine-derived alkaloid from Sophora flavescens with therapeutic potential for non-small cell lung cancer through ROS-mediated pyroptosis and autophagy.

BACKGROUND: Novel compounds and more efficient treatment options are urgently needed for the treatment of non-small cell lung cancer (NSCLC). The decoction of Sophora flavescens has been used to treat NSCLC in the clinic, and matrine-type alkaloids are generally considered to be the key pharmacodynamic material basis. But the previous study showed that common matrine-type alkaloids exhibit significant cytotoxicity only when at concentrations close to the millimolar (mM) level. The key antitumor alkaloids in S. flavescens seem to have not yet been revealed. PURPOSE: The aim of this study was to screen water-soluble matrine alkaloid with novel skeleton and enhanced activity from S. flavescens, and to reveal the pharmacological mechanism of its therapeutic effect on NSCLC. METHODS: Alkaloid was obtained from S. flavescens by chromatographic separation methods. The structure of alkaloid was determined by spectroscopic methods, and single-crystal X-ray diffraction. The mechanism of anti-NSCLC in vitro with cellular models was evaluated by MTT assay, western blotting, cell migration and invasion assay, plate colony-formation assay, tube formation assay, immunohistochemistry assay, hematoxylin and eosin staining. The antitumor efficacy in vivo was test in NSCLC xenograft models. RESULTS: A novel water-soluble matrine-derived alkaloid incorporating 6/8/6/6 tetracyclic ring system, named sophflarine A (SFA), was isolated from the roots of S. flavescens. SFA had significantly enhanced cytotoxicity compared with the common matrine-type alkaloids, having an IC50 value of 11.3 µM in A549 and 11.5 µM in H820 cells at 48 h. Mechanistically, SFA promoted NSCLC cell death by inducing pyroptosis via activating the NLRP3/caspase-1/GSDMD signaling pathway, and inhibited cancer cell proliferation by increasing the ROS production to activate autophagy via blocking the PI3K/AKT/mTOR signaling pathway. Additionally, SFA also inhibited NSCLC cell migration and invasion by suppressing EMT pathway, and inhibited cancer cell colony formation and human umbilical vein endothelial cell angiogenesis. In concordance with the above results, SFA treatment blocked tumor growth in an A549 cell-bearing orthotopic mouse model. CONCLUSION: This study revealed a potential therapeutic mechanism of a novel matrine-derived alkaloid, which not only described a rational explanation for the clinical utilization of S. flavescens, but also provided a potential candidate compound for NSCLC treatment.

A Self-Reinforcing Nanoplatform for Highly Effective Synergistic Targeted Combinatary Calcium-Overload and Photodynamic Therapy of Cancer.

While calcium-overload-mediated therapy (COMT) is a promising but largely untapped therapeutic strategy, combinatory therapy greatly boosts treatment outcomes with integrated merits of different therapies. Herein, a BPQD@CaO2 -PEG-GPC3Ab nanoplatform is formulated by integrating calcium peroxide (CaO2 ) and black phosphorus quantum dot (BPQD, photosensitizer) with active-targeting glypican-3 antibody (GPC3Ab), for combinatory photodynamic therapy (PDT) and COMT in response to acidic pH and near-infrared (NIR) light, wherein CaO2 serves as the reservoir of calcium ions (Ca2+ ) and hydrogen peroxide (H2 O2 ). Navigated by GPC3Ab to tumor cells at acidic pH, the nanoparticle disassembles to CaO2 and BPQD; CaO2 produces COMT Ca2+ and H2 O2 , while H2 O2 makes oxygen (O2 ) to promote PDT; under NIR irradiation BPQD facilitates not only the conversion of O2 to singlet oxygen (1 O2 ) for PDT, but also moderate hyperthermia to accelerate NP dissociation to CaO2 and BPQD, and conversions of CaO2 to Ca2+ and H2 O2 , and H2 O2 to O2 , to enhance both COMT and PDT. After supplementary ionomycin treatment to induce intracellular Ca2+ bursts, the multimodal therapeutics strikingly induce hepatocellular carcinoma apoptosis, likely through the activation of the calpains and caspases 12, 9, and 3, up-regulation of Bax and down-regulation of Bcl-2 proteins. This nanoplatform enables a mutually-amplifying and self-reinforcing synergistic therapy.

Black Phosphorus Quantum Dots Cause Nephrotoxicity in Organoids, Mice, and Human Cells.

Quantum dots (QDs) have numerous potential applications in lighting, engineering, and biomedicine. QDs are mainly excreted through the kidney due to their ultrasmall sizes; thus, the kidneys are target organs of QD toxicity. Here, an organoid screening platform is established and used to study the nephrotoxicity of QDs. Organoids are templated from monodisperse microfluidic Matrigel droplets and found to be homogeneous in both tissue structure and functional recapitulation within a population and suitable for the quantitative screening of toxic doses. Kidney organoids are proved displaying higher sensitivity than 2D-cultured cell lines. Similar to metal-containing QDs, black phosphorus (BP)-QDs are found to have moderate toxicity in the kidney organoids. The nephrotoxicity of BP-QDs are validated in both mice and human renal tubular epithelial cells. BP-QDs are also found to cause insulin insensitivity and endoplasmic reticulum (ER) stress in the kidney. Furthermore, ER stress-related IRE1α signaling is shown to mediate renal toxicity and insulin insensitivity caused by BP-QDs. In summary, this work demonstrates the use of constructed kidney organoids as 3D high-throughput screening tools to assess nanosafety and further illuminates the effects and molecular mechanisms of BP-QD nephrotoxicity. The findings will hopefully enable improvement of the safety of BP-QD applications.

Systematic investigation of intracellular trafficking behavior of one-dimensional alumina nanotubes.

Nanotube materials exhibit high drug loading capacity and controlled drug release properties, providing new opportunities for drug delivery. However, the intracellular trafficking paths of 1-dimensional (1D) nanostructured materials are poorly understood compared to their spherical counterparts, impeding the broad application of 1D materials as drug carriers. Here, we report the intracellular trafficking mechanism of nontoxic and biocompatible nanomaterials called anodic alumina nanotubes (AANTs), a model for 1D materials with a geometry that can be precisely engineered. The results indicated that AANTs enter the cells mainly by caveolin endocytosis and micropinocytosis and that cells use a novel macropinocytosis-late endosomes (LEs)-lysosomes route to transport AANTs. Moreover, liposomes (marked by DsRed-Rab18) are fully involved in the classical pathway of early endosomes (EEs)/LEs developing into lysosomes. The AANTs were delivered to the cells via two pathways: slow endocytosis recycling and GLUT4 exocytosis vesicles. The AANTs also induced intracellular autophagy and then degraded via the endolysosomal pathway. Blocking endolysosomal pathways using autophagy inhibitors prevented the degradation of AANTs through lysosomes. Our results add new insights into the pathways and mechanisms of intracellular trafficking of AANTs, and suggest that intracellular trafficking and lysosomal degradation are highly interdependent and important for efficient drug delivery, and should be evaluated together for drug carrier development.

A multifunctional nanoplatform for cancer chemo-photothermal synergistic therapy and overcoming multidrug resistance.

The integration of various therapy strategies into a single nanoplatform for synergistic cancer treatment has presented a great prospect. Herein, docetaxel (DTX)-loaded poly lactic-co-glycolic acid (PLGA)-coated polydopamine modified with d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) was synthesized for chemo-photothermal synergistic therapy against cancer. Firstly, the DTX-loaded PLGA NPs were prepared by a facile and robust nanoprecipitation method. Then, they were coated with dopamine to achieve the photothermal effects and to be further modified with TPGS, which can inhibit the P-glycoprotein-mediated multidrug resistance (MDR). The near-infrared (NIR) laser irradiation triggered DTX release from DTX-loaded PLGA NPs@PDA-TPGS, and then the chemo-photothermal therapy effect could be enhanced. The in vitro experimental results illustrated that DTX-loaded PLGA NPs@PDA-TPGS exhibits excellent photothermal conservation properties and remarkable cell-killing efficiency. In vivo antitumor studies further confirmed that DTX-loaded PLGA NPs@PDA-TPGS could present an outstanding synergistic antitumor efficacy compared with any monotherapy. This work exhibits a novel nanoplatform, which could not only load chemotherapy drugs efficiently, but could also improve the therapeutic effect of chemotherapy drugs by overcoming MDR and light-mediated photothermal cancer therapy.

BRG1, the ATPase subunit of SWI/SNF chromatin remodeling complex, interacts with HDAC2 to modulate telomerase expression in human cancer cells.

Telomerase is often upregulated during initiation and/or progression of human tumors, suggesting that repression of telomerase might inhibit cancer growth or progression. Here, we report that BRG1, the ATPase subunit of the SWI/SNF chromatin remodeling complex, is a general suppressor of hTERT transcription in human cancer cells. While overexpression of BRG1 inhibits hTERT transcription, depletion of BRG1 stimulates transcription of hTERT, leading to higher telomerase activity and longer telomeres. Chromatin-immunoprecipitation assays revealed that BRG1 binds to the transcription start site (TSS) of the hTERT promoter and forms a ternary complex with histone deacetylase 2 (HDAC2). BRG1 remodels chromatin structure to facilitate the action of HDAC2, leading to deacetylation of H3K9ac and H4ac at the TSS and suppression of hTERT transcription. On the other hand, ß-catenin binds to the TSS and stimulates hTERT transcription. Thus, BRG1/HDAC2 and ß-catenin constitute a manipulative apparatus at the TSS to play opposite but complementary roles in regulating hTERT expression. These results uncover a yin-yang mechanism in modulating hTERT transcription and provide explanation for limited transcription of hTERT in human cancer cells. BRG1/HDAC2 may have a potential as an anti-cancer therapeutic and/or for reactivating cellular proliferative capacity in the context of in vitro tissue engineering.

The natural compound magnolol inhibits invasion and exhibits potential in human breast cancer therapy.

Invasion and metastasis are the main causes of treatment failure and death in breast cancer. Thus, novel invasion-based therapies such as those involving natural agents are urgently required. In this study, we examined the effects of magnolol (Mag), a compound extracted from medicinal herbs, on breast cancer cells in vitro and in vivo. Highly invasive cancer cells were found to be highly sensitive to treatment. Mag markedly inhibited the activity of highly invasive MDA-MB-231 cells. Furthermore, Mag significantly downregulated matrix metalloproteinase-9 (MMP-9) expression, an enzyme critical to tumor invasion. Mag also inhibited nuclear factor-κB (NF-κB) transcriptional activity and the DNA binding of NF-κB to MMP-9 promoter. These results indicate that Mag suppresses tumor invasion by inhibiting MMP-9 through the NF-κB pathway. Moreover, Mag overcame the promoting effects of phorbol 12-myristate 13-acetate (PMA) on the invasion of MDA-MB-231 cells. Our findings reveal the therapeutic potential and mechanism of Mag against cancer.

Protective effects of Lactobacillus rhamnosus GG against human rotavirus-induced diarrhoea in a neonatal mouse model.

Group A human rotaviruses (RV) are a leading cause of severe dehydration and gastroenteritis in infants and young children. A large body of evidence suggests that Lactobacillus rhamnosus GG (LGG) has an effect on the incidence and severity of acute RV-induced diarrhoea; however, the timing and dosage of LGG treatment remains controversial. In the present study, a neonatal mouse model with human RV-induced diarrhoea was set up and the pathophysiological characteristics of the animals were examined. Our results indicated that RV-infected mice developed diarrhoea, accompanied by increased secretion of intestinal mucosa sIgA and serum interferon (IFN)-γ, tumour necrosis factor (TNF)-α, as well as decreased serum IgA. In addition, epithelium vacuolation was noticed in the jejunum microvillus of RV-infected mice. After intragastric administration of low (2 × 10(5) CFU), middle (2 × 10(7) CFU) or high (2 × 10(9) CFU) levels of LGG for four consecutive days before or after RV infection respectively, the RV-infected mice showed a shortened duration of diarrhoea and decreased epithelium vacuolation in the jejunum. Administration of a high dose of LGG before the RV infection was found to have better protective effects against RV infection than other regimens. This study demonstrates that the protective effects of LGG against RV-induced diarrhoea are highly correlated with the timing and dosage of LGG administration in neonatal mice.

Adding perches for cross-pollination ensures the reproduction of a self-incompatible orchid.

BACKGROUND: Outcrossing is known to carry genetic advantages in comparison with inbreeding. In many cases, flowering plants develop a self-incompatibility mechanism, along with a floral component adaptation mechanism, to avoid self-pollination and to promote outbreeding. Orchids commonly have a lip in their flower that functions as the a visiting plate for insect pollinators. Aside from the lip, however, many species (including Coelogyne rigida) have sheaths around the axis of inflorescence. The function of these sheaths remains unknown, and has long been a puzzle to researchers. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the function of these sheaths in relation to the lip and the pollinators, as well as their role in the modes of pollination and reproduction of Coelogyne rigida in 30 flowering populations of orchids in the limestone area of Southeast Yunnan, China. We found that self-incompatible C. rigida developed specialized bird perches around the basal axis of inflorescence to attract sunbirds and to complement their behavioral tendency to change foraging locations frequently. This self-incompatibility mechanism operates separately from the floral component adaptation mechanism. This mechanism thus prevents bees from repeatedly visiting the floral lip of the same plant which, in turn, results in autogamy. In this way, instead of preventing autogamy, C. rigida responds to these negative effects through a highly efficient cross-pollination method that successfully transfers pollen to different plants. CONCLUSIONS: The proposed method ensures reproductive success, while offsetting the infertile self-pollination by insects, thereby reducing mating costs and addressing the lack of cross-pollination. The adaptation provides a novel and striking example of structural adaptation that promotes cross-pollination in angiosperms.

Gambogenic acid-induced time- and dose-dependent growth inhibition and apoptosis involving Akt pathway inactivation in U251 glioblastoma cells.

Glioblastoma multiforme is the most common and aggressive type of primary brain tumor. Uncontrolled activation of the PI3K/Akt signaling pathway resulting from genetic alterations in phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and epidermal growth factor receptor (EGFR) correlates with poor prognosis and resistance to chemotherapy and radiotherapy of glioblastomas. In this study, we found that gambogenic acid (GNA), a polyprenylated xanthone isolated from the traditional medicine gamboge, efficiently arrested the cell cycle at the G(0)/G(1) phase by specifically repressing the expression of cyclin D1 and cyclin E, suppressed cell proliferation, colony formation and cell migration, and induced caspase-dependent apoptosis in U251 glioblastoma cells in a time- and dose-dependent manner. The pro-apoptotic effect of GNA on U251 cells was shown to be mediated through inactivation of the Akt pathway, because GNA efficiently suppressed the expression level of EGFR and reduced the phosphorylation of Akt (T308) and GSK3ß (S9). Furthermore, the combined treatment with LY294002, a specific inhibitor of the PI3K/Akt kinase pathway, and GNA showed a synergistic or additive effect on the growth of U251 cells. Our results showed that GNA is a promising therapeutic agent for glioblastomas.

Pollination: self-fertilization strategy in an orchid.

Mating in flowering plants normally relies on animals, wind, gravity or secretion to convey pollen grains from the male (anther) to the female (stigma) organ. Here we describe a new type of self-pollination mechanism in the tree-living orchid Holcoglossum amesianum, in which the bisexual flower turns its anther against gravity through 360 degrees in order to insert pollen into its own stigma cavity - without the aid of any pollinating agent or medium. This mode of self-pollination, which occurs under windless, drought conditions when insects are scarce, adds to the variety of mechanisms that have evolved in angiosperms to ensure their reproductive success.