Dextran-Cholesterol Carrier Encapsulated Efficient Photosensitizer for the Photodynamic Killing of Cancer Cells.

Selective photodynamic therapy (PDT) for cancer cells is more efficient and much safer. Most selective PDTs are realized by antigene-biomarker or peptide-biomarker interactions. Here, we modified dextran with hydrophobic cholesterol as a photosensitizer carrier to selectively target cancer cells, including colon cancer cells, and fulfilled selective PDT. The photosensitizer was designed with regular Aggregation-Induced Emission (AIE) units, including triphenylamine and 2-(3-cyano-4,5,5-trimethylfuran-2-ylidene)propanedinitrile. The AIE units can help to decrease the quenching effect in the aggregate state. The efficiency of the photosensitizer is further improved via the heavy atom effect after bromination modification. We found that the obtained photosensitizer nanoparticles could selectively target and ablate cancer cells after encapsulation into the dextran-cholesterol carrier. This study indicates that the polysaccharide-based carrier may have potential for cancer-targeting therapy beyond expectations.

Taxonomic and functional diversity of Dendrobium officinale microbiome in Danxia habitat.

AIMS: Microbial communities that inhabit plants are crucial for plant survival and well-being including growth in stressful environments. The medicinal plant, Dendrobium officinale grows in the barren soils of the Danxia Habitat. However, the microbiome composition and functional potential for growth of this plant in this environment are still unexplored. METHODS AND RESULTS: In this study, we analysed the taxonomic and functional diversity of the D. officinale Microbiome by metagenomic sequencing of both rhizosphere and endosphere samples. A total of 155 phyla, 122 classes, 271 orders, 620 families and 2194 genera were identified from all samples. The rhizospheric microbes (DXRh) were mainly composed of Proteobacteria and Acidobacteria, while Basidiomycota and Ascomycota were the most dominant phyla in root endosphere (DXRo) and stem endosphere (DXS), respectively. Most of the dominant microbial communities had been reported to have diverse functional potentials that can help plant growth and development in stressful and nutrient-deprived ecological environmental. These include plant growth promoting rhizobacteria (PGPR) such as Massilia, Pseudomonas, Bradyrhizobium, Klebsiella, Streptomyces, Leclercia, Paenibacillus, Frankia and Enterobacter in the DXRh, Tulasnella and Serendipita in the DXRo, Colletotrichum and Burkholderia in the DXS and Paraburkholderia, Rhizophagus and Acetobacter in endosphere. Analysis using the KEGG, eggNOG and CAZy databases showed that metabolic pathways such as carbohydrate metabolism, amino acid metabolism, energy metabolism, genetic information processing and environmental information processing are significantly abundant, which may be related to the survival, growth and development of D. officinale in a stressful environment. CONCLUSIONS: We speculated that the microbial community with diverse taxonomic structures and metabolic functions inhabiting in different niches of plants supports the survival and growth of D. officinale in the stressful environment of Danxia Habitat. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided an important data resource for microbes associated with D. officinale and theoretical foundation for further studies.

Structural Characterization of Polysaccharides from Dendrobium officinale and Their Effects on Apoptosis of HeLa Cell Line.

Dendrobium officinale is a widely used medicinal plant in China with numerous bio-activities. However, the main structure and anti-tumor activity of the polysaccharides from this plant have not been investigated. In this study, we elucidated the main structure of polysaccharides purified with DEAE and Sephadex G-25 from Dendrobium officinale grown under different planting conditions. In addition, the anti-tumor activity was tested via MTT assays. The results showed that the polysaccharides of Dendrobium officinale grown under different conditions were almost the same, with slight differences in the branched chain; both polysaccharide fractions consisted of (1→4)-linked mannose and (1→4)-linked glucose, with an O-acetyl group in the mannose. After degradation, the polysaccharide fractions from wild plants showed significant anti-proliferation activity in HeLa cells. The fractions F1 and F3 induced apoptosis by up-regulating the expression of ERK, JNK, and p38. We concluded that polysaccharides from Dendrobium officinale planted in the wild exhibit significant anti-tumor effects only after being degraded to smaller molecular weight species. The planting mode is a significant factor in the pharmacological activity of Dendrobium officinale. We advise that the planting conditions for Dendrobium officinale should be changed.

Purification, Characterization and Biological Activity of Polysaccharides from Dendrobium officinale.

Polysaccharide (DOPA) from the stem of D. officinale, as well as two fractions (DOPA-1 and DOPA-2) of it, were isolated and purified by DEAE cellulose-52 and Sephacryl S-300 chromatography, and their structural characteristics and bioactivities were investigated. The average molecular weights of DOPA-1 and DOPA-2 were 394 kDa and 362 kDa, respectively. They were mainly composed of d-mannose, d-glucose, and had a backbone consisting of 1,4-linked ß-d-Manp and 1,4-linked ß-d-Glcp with O-acetyl groups. Bioactivity studies indicated that both DOPA and its purified fractions (DOPA-1 and DOPA-2) could activate splenocytes and macrophages. The D. officinale polysaccharides had stimulatory effects on splenocytes, T-lymphocytes and B-lymphocytes, promoting the cell viability and NO production of RAW 264.7 macrophages. Furthermore, DOPA, DOPA-1 and DOPA-2 were found to protect RAW 264.7 macrophages against hydrogen peroxide (H2O2)-induced oxidative injury by promoting cell viability, suppressing apoptosis and ameliorating oxidative lesions. These results suggested that D. officinale polysaccharides possessed antioxidant activity and mild immunostimulatory activity.

Dendrobium officinale polysaccharide-based carrier to enhance photodynamic immunotherapy.

Photodynamic therapy (PDT) eradicates tumors via the generation of toxic reactive oxygen species (ROS) by activation of a photosensitizer (PS) with appropriate light. Local PDT toward tumors can trigger the immune response to inhibit distant tumors, but the immune response is usually insufficient. Herein, we used a biocompatible herb polysaccharide with immunomodulatory activity as the carrier of PS to enhance the immune inhibition of tumors after PDT. The Dendrobium officinale polysaccharide (DOP) is modified with hydrophobic cholesterol to serve as an amphiphilic carrier. The DOP itself can promote dendritic cell (DC) maturation. Meanwhile, TPA-3BCP are designed to be cationic aggregation-induced emission PS. The structure of one electron-donor linking to three electron-acceptors endows TPA-3BCP with high efficiency to produce ROS upon light irradiation. And the nanoparticles are designed with positively charged surfaces to capture antigens released after PDT, which can protect the antigens from degradation and improve the antigen-uptake efficiency by DCs. The combination of DOP-induced DC maturation and antigen capture-increased antigen-uptake efficiency by DCs significantly improves the immune response after DOP-based carrier-mediated PDT. Since DOP is extracted from the medicinal and edible Dendrobium officinale, the DOP-based carrier we designed is promising to be developed for enhanced photodynamic immunotherapy in clinic.

Anti-colon Cancer Effects of Dendrobium officinale Kimura & Migo Revealed by Network Pharmacology Integrated With Molecular Docking and Metabolomics Studies.

Objective: The present study aimed to investigate the potential mechanism of Dendrobium officinale (D. officinale) on colorectal cancer and the relevant targets in the pathway using a network pharmacological approach. Methods: (1) We identified the major bioactive components of D. officinale by UPLC-ESI-MS/MS and established the in-house library by using the literature mining method. (2) Target prediction was performed by SwissADME and SwissTargetPrediction. (3) A protein-protein interaction (PPI) network and component-target-pathway network (C-T-P network) were constructed. (4) The GO pathways and the KEGG pathway enrichment analysis were carried out by the Metascape database. (5) Molecular docking was performed by AutoDock software. (6) A series of experimental assays including cell proliferation, cell invasion and migration, and TUNEL staining in CRC were performed in CRC cell lines (HT-29, Lovo, SW-620, and HCT-116) to confirm the inhibitory effects of D. officinale. Results: (1) In total, 396 candidate active components of D. officinale were identified by UPLC-ESI-MS/MS and selected from the database. (2) From OMIM, GeneCards, DrugBank, and TTD databases, 1,666 gene symbols related to CRC were gathered, and (3) 34 overlapping gene symbols related to CRC and drugs were obtained. (4) These results suggested that the anti-CRC components of D. officinale were mainly apigenin, naringenin, caffeic acid, γ-linolenic acid, α-linolenic acid, cis-10-heptadecenoic acid, etc., and the core targets of action were mainly ESR1, EGFR, PTGS2, MMP9, MMP2, PPARG, etc. (5) The proliferation of muscle cells, the regulation of inflammatory response, the response of cells to organic cyclic compounds, and the apoptotic signaling pathway might serve as principal pathways for CRC treatment. (6) The reliability of some important active components and targets was further validated by molecular docking. The molecular docking analysis suggested an important role of apigenin, naringenin, PTGS2, and MMP9 in delivering the pharmacological activity of D. officinale against CRC. (7) These results of the evaluation experiment in vitro suggested that D. officinale had a strong inhibitory effect on CRC cell lines, and it exerted anti-CRC activity by activating CRC cell apoptosis and inhibiting CRC cell migration and invasion. Conclusion: This study may provide valuable insights into exploring the mechanism of action of D. officinale against CRC.

Effects of Different Molecular Weight Polysaccharides From Dendrobium officinale Kimura & Migo on Human Colorectal Cancer and Transcriptome Analysis of Differentially Expressed Genes.

We investigated the antitumor effects of four fractions of Dendrobium officinale Kimura & Migo (D. officinale) polysaccharides with different molecular weights (Mw), Astragalus membranaceus polysaccharides (APS) and Lentinus edodes polysaccharides (LNT) on colorectal cancer (CRC) using a zebrafish xenograft model. Transcriptome sequencing was performed to further explore the possible antitumor mechanisms of D. officinale polysaccharides. Fractions of D. officinale polysaccharides, LNT, and APS could significantly inhibit the growth of HT-29 cells in a zebrafish xenograft model. One fraction of D. officinale polysaccharides called DOPW-1 (Mw of 389.98 kDa) exhibited the strongest tumor inhibition. Compared with the control group, RNA-seq revealed that the DOPW-1-treated experimental group had 119 differentially expressed genes (DEGs), of which 45 had upregulated expression and 74 had downregulated expression. Analyses using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes suggested that the pathway "apoptosis-multiple species" was the most significantly enriched. Our data indicated that 1) fractions of D. officinale polysaccharides of Mw 389.98 kDa were most suitable against CRC; 2) DOPW-1 could be developed into a clinical agent against CRC; and 3) an apoptosis pathway is important for DOPW-1 to inhibit the proliferation of HT-29 cells.

Gigantol inhibits proliferation and enhances DDP-induced apoptosis in breast-cancer cells by downregulating the PI3K/Akt/mTOR signaling pathway.

AIMS: Gigantol is a bibenzyl compound isolated from orchids of the genus Dendrobium. Gigantol has been demonstrated to possess various pharmacologic (including anticancer) effects. Cisplatin (DDP) has been used and studied as the first-line agent for breast cancer (BC) treatment. Often, its efficacy is jeopardized due to intolerance and organ toxicity. We investigated if gigantol could enhance the anticancer effects of DDP in BC cells and its underlying mechanism of action. MAIN METHODS: The potential pathway of gigantol in BC cells was detected by network-pharmacology and molecular-docking studies. The proliferation and apoptosis of BC cell lines were measured by the MTT assay, colony formation, Hoechst-33342 staining, and flow cytometry. Protein expression was measured by western blotting. KEY FINDINGS: Gigantol could inhibit proliferation of BC cells and enhance DDP-induced apoptosis. According to the results of western blotting, gigantol reinforced DDP-induced anticancer effects through downregulation of the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway in BC cells. The effects were consistent with those of the pathway inhibitor LY294002. SIGNIFICANCE: Our data might provide new insights into the underlying antitumor effect of gigantol in BC cells. This enhancement effect in the combination of gigantol and DDP may provide many therapeutic benefits in clinical treatment regimens against BC.

Functional analysis of a novel C-glycosyltransferase in the orchid Dendrobium catenatum.

Flavonoids, which are a diverse class of phytonutrients, are used by organisms to respond to nearly all abiotic stresses and are beneficial for human health. Glycosyltransferase, used during the last step of flavonoid biosynthesis, is important in flavonoid enrichment. However, little is known about glycosyltransferase in the orchid Dendrobium catenatum (D. officinale). In this study, we isolated a novel C-glycosyltransferase (designated DcaCGT) from the orchid D. catenatum by identifying and analyzing 82 putative genes in the GT1 family. DcaCGT could specifically catalyze not only di-C-glycosylation but also O-glycosylation. Apart from the normal function of catalyzing 2-hydroxynaringenin and phloretin to the respective di-C-glycosides, DcaCGT also catalyzes apigenin to cosmosiin. Targeted metabolic profiling of the substrates (2-hydroxynaringenin, phloretin, and apigenin) and products (vitexin, isovitexin, vicenin-2, nothofagin, 3',5'-di-C-glucosylphloretin, and cosmosiin) in different tissues showed that vicenin-2 was the most abundant product of this novel enzyme. Cosmosiin was detected in flowers and flower buds. We also established that DcaCGT functions expanded throughout the evolution of D. catenatum. Residual OGT activity may help D. catenatum resist drought stress. Our study illustrates the function, origin, and differentiation of DcaCGT and provides insights into glycosylation and molecular propagation processes, which can be used to improve the production of flavonoids by the cultivated medicinal plant D. catenatum.

Network Analysis of Transcriptome and LC-MS Reveals a Possible Biosynthesis Pathway of Anthocyanins in Dendrobium officinale.

Anthocyanins, a group of flavonoids, are widely present in plants and determine the colors of the peels of stems, fruits, and flowers. In this study, we used UHPLC-ESI-MS to identify anthocyanins in the herbal plant Dendrobium officinale, which has been used for centuries in China. The results indicated that the total anthocyanin content in samples from Guangxi was the highest. Seven anthocyanins were identified, and the fragmentation pathways were proposed from D. officinale. Most of the identified anthocyanins were composed of cyanidin and sinapoyl groups. We also carried out that the sinapoyl group had active sites on breast cancer receptors by using Schrödinger. The relative levels of the 7 anthocyanins in the samples from the three locations were determined. Transcriptomic analysis was used to analyze the sinapoyl anthocyanin synthesis-related genes in plants, such as genes encoding UGTs and serine carboxypeptidase. We speculated that sinapoyl anthocyanin biosynthesis was associated with the activities of certain enzymes, including chalcone flavonone isomerase-like, hydroxycinnamoyltransferase 1, UGT-83A1, UGT-88B1 isoform X1, serine carboxypeptidase-like 18 isoform X3, and serine carboxypeptidase-like 18.