Structure-guided design of C3-branched swainsonine as potent and selective human Golgi α-mannosidase (GMII) inhibitor.

The human Golgi α-mannosidase, hGMII, removes two mannose residues from GlcNAc-Man5GlcNAc2 to produce GlcNAcMan3GlcNAc2, the precursor of all complex N-glycans including tumour-associated ones. The natural product GMII inhibitor, swainsonine, blocks processing of cancer-associated N-glycans, but also inhibits the four other human α-mannosidases, rendering it unsuitable for clinical use. Our previous structure-guided screening of iminosugar pyrrolidine and piperidine fragments identified two micromolar hGMII inhibitors occupying the enzyme active pockets in adjacent, partially overlapping sites. Here we demonstrate that fusing these fragments yields swainsonine-configured indolizidines featuring a C3-substituent that act as selective hGMII inhibitors. Our structure-guided GMII-selective inhibitor design complements a recent combinatorial approach that yielded similarly configured and substituted indolizidine GMII inhibitors, and holds promise for the potential future development of anti-cancer agents targeting Golgi N-glycan processing.

(5S)-5-Benzylswainsonines as potent and selective inhibitors of Golgi α-mannosidase II: synthesis, enzyme evaluation and molecular modelling.

Development of novel anti-cancer therapeutics based on Golgi α-mannosidase II (GMII) inhibition is considerably impeded by an undesired co-inhibition of lysosomal α-mannosidase leading to severe side-effects. In this contribution, we describe a fully stereoselective synthesis of (5S)-5-[4-(halo)benzyl]swainsonines as highly potent and selective inhibitors of GMII. The synthesis starts from a previously reported aldehyde readily available from l-ribose, and the key features include an intramolecular reductive amination with substrate-controlled stereoselectivity and a late-stage derivatisation of the benzyl group via ipso-substitution. These novel swainsonine analogues were found to be nanomolar inhibitors of the Golgi-type α-mannosidase AMAN-2 (Ki = 23-75 nM) with excellent selectivity (selectivity index = 205-870) over the lysosomal-type Jack bean α-mannosidase. Finally, molecular docking and pKa calculations were performed to provide more insight into the structure of the inhibitor:enzyme complexes, and a pair interaction energy analysis (FMO-PIEDA) was carried out to rationalise the observed potency and selectivity of the inhibitors.

Swainsonine promotes apoptosis by impairing lysosomal function and inhibiting autophagic degradation in rat primary renal tubular epithelial cells.

Swainsonine (SW), an indolizidine alkaloid, is the primary toxin in locoweeds that causes toxicity syndrome in livestock. Current research shows that SW can induce both apoptosis and autophagy. However, the relationship between, and regulatory mechanism of, autophagy and apoptosis in SW-mediated cytotoxicity remain unclear. In this study, we investigated the role of autophagy and apoptosis in SW-induced cytotoxicity in rat primary renal tubular epithelial cells (RTECs). We examined the effect of SW on lysosomal function using western blotting, transmission electron microscopy, fluorescent microscopy, and flow cytometry. The results showed that SW induced both autophagy and apoptosis, and autophagy protected RTECs from cellular damage. Activating autophagy using rapamycin (Rapa) inhibited apoptosis, while suppressing autophagy using bafilomycin A1 (Baf A1) greatly enhanced SW-induced apoptosis. SW treatment suppressed the expression of lysosomal-related proteins, and co-incubation with SW and aloxistatin (E64d) further promoted apoptosis and LC3-II accumulation in RTECs. These results suggest that SW causes toxicity by disrupting lysosomal dysfunction, inhibiting autophagic degradation, and promoting apoptosis.

Curcumin Derivative GT863 Inhibits Amyloid-Beta Production via Inhibition of Protein N-Glycosylation.

Amyloid-ß (Aß) peptides play a crucial role in the pathogenesis of Alzheimer's disease (AD). Aß production, aggregation, and clearance are thought to be important therapeutic targets for AD. Curcumin has been known to have an anti-amyloidogenic effect on AD. In the present study, we performed screening analysis using a curcumin derivative library with the aim of finding derivatives effective in suppressing Aß production with improved bioavailability of curcumin using CHO cells that stably express human amyloid-ß precursor protein and using human neuroblastoma SH-SY5Y cells. We found that the curcumin derivative GT863/PE859, which has been shown to have an inhibitory effect on Aß and tau aggregation in vivo, was more effective than curcumin itself in reducing Aß secretion. We further found that GT863 inhibited neither ß- nor γ-secretase activity, but did suppress γ-secretase-mediated cleavage in a substrate-dependent manner. We further found that GT863 suppressed N-linked glycosylation, including that of the γ-secretase subunit nicastrin. We also found that mannosidase inhibitors that block the mannose trimming step of N-glycosylation suppressed Aß production in a similar fashion, as was observed as a result of treatment with GT863. Collectively, these results suggest that GT863 downregulates N-glycosylation, resulting in suppression of Aß production without affecting secretase activity.

Swainsonine protects H9c2 cells against lipopolysaccharide-induced apoptosis and inflammatory injury via down-regulating miR-429.

Pediatric myocarditis (PM) is usually related to myocardial dysfunction. Generally, 30% of PM patients will die or undergo heart transplantation. Swainsonine (SW) is a natural alkaloid and an anti-cancer substance. Our goal was to determine the roles of SW in PM in current study. H9c2 cells were pre-treated by lipopolysaccharide (LPS). Viability and apoptosis were evaluated utilizing CCK-8 assay and flow cytometry. Inflammatory cytokines' mRNA expression and production were assessed by western blot and ELISA. Western blot was utilized to distinguish apoptosis and immune-related factors expression. Sequentially, the abovementioned parameters were reassessed when miR-429 was overexpressed. LPS declined viability as well as raised apoptosis and inflammatory injury in H9c2 cells. SW alleviated apoptosis and inflammatory injury induced by LPS. MiR-429 expression was elevated by LPS and suppressed by SW. SW-induced the increasing of viability and the reduction of inflammatory injury were reversed by overexpression of miR-429. Eventually, SW inhibited p38MAPK/NF-κB pathway which activated by LPS via overexpressing miR-429. SW exerted its anti-apoptosis and anti-inflammatory function in LPS-treated H9c2 cells through p38MAPK/NF-κB pathway and down-regulation of miR-429.

Sesquiterpenoids and mycotoxin swainsonine from the locoweed endophytic fungus Alternaria oxytropis.

Oxytropiols A-J, ten undescribed guaiane-type sesquiterpenoids, and the mycotoxin swainsonine (SW) were isolated from the locoweed endophytic fungus Alternaria oxytropis. The chemical structures of these sesquiterpenoids were elucidated on the basis of HR-ESI-MS and NMR data including 1H, 13C, HSQC, 1H-1H COSY, HMBC, and NOESY spectra, and the absolute configurations of these compounds were determined using a modified Mosher's method and X-ray diffraction spectroscopy. A possible biosynthetic pathway of these guaiane-type sesquiterpenoids is discussed, and proposed that post-modification oxidative enzymes might form these highly polyhydroxylated structures. Compound 1 displayed biological effects on the root growth of Arabidopsis thaliana, and SW displayed cytotoxicity against A549 and HeLa cancer cell lines.

Swainsonine inhibits proliferation and collagen synthesis of NIH-3T3 cells by declining miR-21.

Swainsonine (SW) is an indolizidine alkaloid first discovered in Swainsona canescens. This study explored the effects of SW on mouse embryo fibroblast NIH-3T3 cell proliferation and collagen synthesis, as well as potential molecule mechanisms. We discovered that SW exposure lowered the viability and proliferation of NIH-3T3 cells. The collagen synthesis was reduced after SW exposure, as evidenced by declines of the mRNA and protein levels of collagen I (CoI I), collagen III (CoI III) and α-smooth muscle actin (α-SMA) in NIH-3T3 cells, as well as reduction of collagen concentration in the culture supernatant of NIH-3T3 cells. Mechanically, transforming growth factor ß1 (TGF-ß1) stimulation elevated the microRNA-21 (miR-21) expression in NIH-3T3 cells. SW reversed the TGF-ß1-caused elevation of miR-21. Up-regulation of miR-21 attenuated the inhibitory influences of SW on NIH-3T3 cell viability, proliferation and collagen synthesis. Silence of miR-21 had converse influence. Besides, SW inactivated PI3K/AKT and NF-κB pathways via declining miR-21. Altogether, SW inhibited the proliferation and collagen synthesis of fibroblast NIH-3T3 might be through declining miR-21 and then suppressing PI3K/AKT and NF-κB pathways. SW may be an effective therapeutic medicine for scar hyperplasia.

Complex N-glycan promotes CD133 mono-ubiquitination and secretion.

CD133 is a widely used cell surface marker of cancer stem cells that plays an important role in tumor initiation and metastasis. Increasing evidence shows that CD133 is secreted to the extracellular space. However, the underlying mechanisms of CD133 secretion remain largely unknown. In this study, we report that secreted CD133 has a complex-type N-glycosylation and is modified by beta1,6GlcNAc N-glycan. We found that inhibition of CD133 complex-type N-glycosylation by swainsonine does not affect the membrane localization of CD133, but significantly reduces CD133 secretion and promotes its accumulation in early endosomes. Moreover, swainsonine reduces CD133 secretion by reducing its mono-ubiquitination and inhibiting the interaction between CD133 and Tsg101. These findings reveal a new mechanism of glycosylation-dependent secretion of CD133.

Swainsonine represses glioma cell proliferation, migration and invasion by reduction of miR-92a expression.

BACKGROUND: Swainsonine is a natural indolizidine alkaloid, its anti-tumor activity has been widely reported in varied cancers. This study aimed to investigate whether Swainsonine exerted anti-tumor impact on glioma cells, likewise uncovered the relative molecular mechanisms. METHODS: After administration with diverse concentrations of Swainsonine, cell growth, migration and invasion in U251 and LN444 cells were appraised by the common-used CCK-8, BrdU, flow cytometry and Transwell assays. MiR-92a mimic, inhibitor and the correlative NC were transfected into U251 and LN444 cells, and assessment of miR-92a expression was by utilizing qRT-PCR. Functions of miR-92a in above-mentioned cell biological processes were analyzed again in Swainsonine-treated cells. The momentous proteins of cell cycle, apoptosis and PI3K/AKT/mTOR pathway were ultimately examined by western blot. RESULTS: Swainsonine significantly hindered cell proliferation through decreasing cell viability, declining the percentage of BrdU cells, down-regulating CyclinD1 and up-regulating p16 expression. Enhancement of percentage of apoptotic cells was presented in Swainsonine-treated cells via activating cleaved-Caspase-3 and cleaved-Caspase-9. Additionally, Swainsonine impeded the abilities of migration and invasion by decreasing MMP-2, MMP-9, Vimentin and E-cadherin. Repression of miR-92a was observed in Swainsonine-treated cells, and miR-92a overexpression overturned the anti-tumor activity of Swainsonine in glioma cells. Finally, western blot assay displayed that Swainsonine hindered PI3K/AKT/mTOR pathway via regulating miR-92a. CONCLUSIONS: These discoveries corroborated that Swainsonine exerted anti-tumor impacts on glioma cells via repression of miR-92a, and inactivation of PI3K/AKT/mTOR signaling pathway.

Swainsonine, an alpha-mannosidase inhibitor, may worsen cervical cancer progression through the increase in myeloid derived suppressor cells population.

Cervical cancer, caused by high oncogenic risk Human Papillomavirus (HPV) infection, continues to be a public health problem, mainly in developing countries. Using peptide phage display as a tool to identify potential molecular targets in HPV associated tumors, we identified α-mannosidase, among other enriched sequences. This enzyme is expressed in both tumor and inflammatory compartment of the tumor microenvironment. Several studies in experimental models have shown that its inhibition by swainsonine (SW) led to inhibition of tumor growth and metastasis directly and indirectly, through activation of macrophages and NK cells, promoting anti-tumor activity. Therefore, the aim of this work was to test if swainsonine treatment could modulate anti-tumor immune responses and therefore interfere in HPV associated tumor growth. Validation of our biopanning results showed that cervical tumors, both tumor cells and leukocytes, expressed α-mannosidase. Ex vivo experiments with tumor associated macrophages showed that SW could partially modulate macrophage phenotype, decreasing CCL2 secretion and impairing IL-10 and IL-6 upregulation, which prompted us to proceed to in vivo tests. However, in vivo, SW treatment increased tumor growth. Investigation of the mechanisms leading to this result showed that SW treatment significantly induced the accumulation of myeloid derived suppressor cells in the spleen of tumor bearing mice, which inhibited T cell activation. Our results suggested that SW contributes to cervical cancer progression by favoring proliferation and accumulation of myeloid cells in the spleen, thus exacerbating these tumors systemic effects on the immune system, therefore facilitating tumor growth.

Swainsonine induces apoptosis of rat cardiomyocytes via mitochondria­mediated pathway.

Swainsonine is an Astragalus membranaceus extract. It is indole, alkaloid, and soluble in water. Its effect on rat cardiomyocytes apoptosis, and the mechanisms underlying that effect, were investigated by inducing apoptosis in H9c2 cells. This was detected by MTT assay, Annexin V-FITC/propidium iodide double staining and western blotting. Flow cytometry and fluorescence microscopy were used to confirm swainsonine's effect on mitochondrial membrane potential and levels of reactive oxygen species, while an ATP-dependent bioluminescence assay kit served to find the ATP contents. Assessment was also carried out for peroxisome proliferator activated receptor γ co-activator 1α (PGC-1α) expression levels as well as those of such apoptosis-associated proteins as Cytochrome c, Caspase-3, B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax). Overall, indications were that swainsonine may have the potential to inhibit viability of cells, decrease expression of PGC-1α, induce mitochondrial dysfunction, upregulate Cytochrome c, Bax and Caspase-3, and downregulate Bcl-2. The suggestion would be that apoptosis may be induced through signalling pathways in H9c2 cells mediated by mitochondria.

Integrin expression and glycosylation patterns regulate cell-matrix adhesion and alter with breast cancer progression.

Integrins are the major cell adhesion glycoproteins involved in cell-extracellular matrix (ECM) interaction and metastasis. Further, glycosylation on integrin is necessary for its proper folding and functionality. Herein, differential expression of integrins viz., αvß3 and αvß6 was examined in MDA-MB-231, MDA-MB-468 and MCF-10A cells, which signify three different stages of breast cancer development from highly metastatic to non-tumorigenic stage. The expression of αvß3 and αvß6 integrins at mRNA and protein levels was observed in all three cell lines and the results displayed a distinct pattern of expression. Highly metastatic cells showed enhanced expression of αvß3 than moderate metastatic and non-tumorigenic cells. The scenario was reversed in case of αvß6 integrin, which was strongly expressed in moderate metastatic and non-tumorigenic cells. N-glycosylation of αvß3 and αvß6 integrins is required for the attachment of cells to ECM proteins like fibronectin. The cell adhesion properties were found to be different in these cancer cells with respect to the type of integrins expressed. The results testify that αvß3 integrin in highly metastatic cells, αvß6 integrin in both moderate metastatic and non-tumorigenic cells play an important role in cell adhesion. The investigation typify that N-glycosylation on integrins is also necessary for cell-ECM interaction. Further, glycosylation inhibition by Swainsonine is found to be more detrimental to invasive property of moderate metastatic cells. Conclusively, types of integrins expressed as well as their N-glycosylation pattern alter during the course of breast cancer progression.

Swainsonine Inhibits Invasion and the EMT Process in Esophageal Carcinoma Cells by Targeting Twist1.

Esophageal cancer is a common gastrointestinal cancer, with a very high mortality rate in patients with metastasis. Swainsonine, a cytotoxic fungal alkaloid, has been shown to inhibit cell growth in esophageal cancer. In the present study, we explored the effects of swainsonine on cell invasion and metastasis in esophageal cancer cells. Human esophageal carcinoma cells were treated with different doses of swainsonine, and then cell viability, invasion, and apoptosis were measured. The mRNA and protein expressions of Twist1, apoptosis- and EMT-related factors, and PI3K/AKT pathway factors were detected by qRT-PCR and Western blot. Swainsonine had no effect on esophageal cancer cell viability and apoptosis, but it significantly decreased cell invasion in a dose-dependent manner. Swainsonine increased the expression of E-cadherin but decreased the expression of N-cadherin, vimentin, ZEB1, and snail in a dose-dependent manner, thereby inhibiting EMT. Last, we found that swainsonine inhibits cell invasion and EMT in the esophageal carcinoma cells by downregulation of Twist1 and deactivation of the PI3K/AKT signaling pathway.

Alteration of the PI3K/Akt signaling pathway by swainsonine affects 17ß-Estradiol secretion in ovary cells.

BACKGROUND: The ingestion of locoweed that contains the toxic indolizidine alkaloid swainsonine (SW) disrupts ovarian function, accompanied by delayed estrus, increased estrous cycle length, delayed conception, and abortion. GOALS: The direct effects of SW on ovary cell steroidogenesis remain unclear. MATERIALS AND METHODS: In this study, Chinese hamster ovary (CHO) cells were used to investigate the effects of SW on estradiol (E2) secretion and cell viability and the mechanisms involved in these processes. RESULTS: CHO cells were treated with SW. 17 ß-Estradiol mRNA expression was decreased in the SW group compared to that in the control group. Various concentrations of E2 and SW were added to cultured cells for 12 h and 36 h. Compared to the control group cells, CYP19A1 expression was decreased in the SW and SW + E2 treatment groups at 12 h and 36 h (P < 0.05). This showed that SW mainly inhibits the last step of estrogen synthesis. When CHO cells were treated with SW, the p-Akt protein levels were significantly decreased compared to that in the control group cells at 12 h and 36 h (P < 0.05). However, the p-Akt expression in the SW + E2 group was not significantly different compared to that in the control group cells (P > 0.05). When CHO cells were treated with SW and SW + E2, the PI3K protein levels were significantly down-regulated compared to that in the control group cells at 12 h and 36 h. CONCLUSION: Taken together, these studies demonstrate that SW is an inhibitor of PI3K/Akt signaling pathway. However, SW blocked PI3K activation in estrogen induction without blocking p-Akt activation in CHO cells. Therefore, SW + E2 blocked upstream but did not affect the downstream of the PI3K/Akt signaling pathway.

Sialylated ß1, 6 branched N-glycans modulate the adhesion, invasion and metastasis of hepatocarcinoma cells.

The mouse hepatocarcinoma cell lines Hca-F and Hca-P have been derived from hepatocarcinoma in mice and metastasize only to the lymph node. Hca-F cells displayed greater lymphatic metastasis ability than Hca-P cells. When the two cell lines were compared for cell surface sialylated ß1,6 branched N-glycans by flow cytometry using L-PHA and SNA, Hca-F cells were found to express significantly higher levels. To explore the effect of increased sialylated ß1,6 branched N-glycans on hepatocarcinoma progression, we inhibit their expression in Hca-F cells by using swainsonine treatment and RNA interference. We found that swainsonine treatment or GnT-V-shRNA transfection significantly inhibited the formation of ß1,6 branched N-glycans, and partially inhibited the expression of α2,6 sialic acids. Knockdown of sialylated ß1,6 branched N-glycans significantly attenuated the invasive and metastatic capability both in vitro and in vivo. Blockade of α2,6 sialic acid expression on Hca-F cell surface by the treatment with neuraminidase caused reduction in cellular adherence to lymph node. In addition, knockdown of sialylated ß1,6 branched N-glycans could decrease the expression of Notch1, NICD1, NICD2 and HES1 in Hca-F cells. Collectively, these findings suggest that increased sialylated ß1,6 branched N-glycans may contribute to hepatocarcinoma progression by altering the adhesive, invasive and metastatic ability to lymph node via Notch signaling pathway.

Betulinic acid and oleanolic acid, natural pentacyclic triterpenoids, interfere with N-linked glycan modifications to intercellular adhesion molecule-1, but not its intracellular transport to the cell surface.

Betulinic acid (3ß-hydroxy-20(29)-lupen-28-oic acid), oleanolic acid (3ß-hydroxy-olean-12-en-28-oic acid), and ursolic acid (3ß-hydroxy-urs-12-en-28-oic acid) are close structural isomers of natural pentacyclic triterpenoid carboxylic acids. We recently identified a unique biological effect of ursolic acid, its inhibition of the intracellular trafficking of glycoproteins. In the present study, we demonstrated that betulinic acid and oleanolic acid did not inhibit the interleukin-1α-induced expression of cell-surface intercellular adhesion molecule-1 (ICAM-1) in human lung carcinoma A549 cells. Nevertheless, betulinic acid and, to a lesser extent, oleanolic acid interfered with N-linked glycan modifications to ICAM-1 in a similar manner to castanospermine (an inhibitor of endoplasmic reticulum α-glucosidases I and II), but not swainsonine (an inhibitor of Golgi α-mannosidase II). Consistent with these results, betulinic acid and oleanolic acid inhibited yeast α-glucosidase activity, but not Jack bean α-mannosidase activity. Thus, to the best of our knowledge, this is the first study to show that betulinic acid and oleanolic acid interfere with N-linked glycan modifications to ICAM-1, but not its intracellular transport to the cell surface.

Alteration of glycan structures by swainsonine affects steroidogenesis in bovine luteal cells.

The indolizidine alkaloid swainsonine (SW), a potent inhibitor of Golgi α-mannosidase II, is considered the primary toxicant in locoweeds causing toxicity syndrome known as locoism in livestock. Locoweed consumption decreases serum progesterone concentration and causes serious disorders in reproductive functions of livestock. However, direct effects of SW on luteal steroidogenic cells (LSCs) remain unclear. In the present study, we investigated the effect of N-glycan processing inhibition by SW on progesterone production and viability in cultured bovine LSCs. Swainsonine (0.1 µg/mL) fully inhibited glycosylation in the LSCs, but it had no effect on viability and progesterone production in the LSCs. Luteinizing hormone is known to promote progesterone production and expressions of steroidogenic acute regulatory protein and scavenger receptor type B class I. Pretreatment of LSCs with SW suppressed each of these effects, possibly by inhibiting LH receptor activity. These results suggest that SW inhibits N-glycan processing, which attenuates LH receptor activity, which, in turn, reduces progesterone production by CL.

The antileukaemic cell cycle regulatory activities of swainsonine purified from Metarhizium anisopliae fermentation broth.

Swainsonine is a Metarhizium secondary metabolite known differentially for its specific mannosidase inhibitory, toxic and therapeutic activities. Here, the standard and purified swainsonine from Metarhizium anisopliae fermentation broth were comparatively evaluated for their in situ antileukaemic activities in human promyelocytic cell line, HL-60. Both the standard (IC50 = 6.96 µM) and purified (IC50 = 9.50 µM) compounds inhibited the leukaemic cell proliferation without inflicting cell membrane disruption at 48 h of post-treatment incubation. The DNA cell cycle analysis showed approximately 48.81% and 60.72% of the treated cells arrested in the synthetic phase (S-phase) at 36 and 48 h, respectively, upon treatment with IC50 concentration of the purified swainsonine. However, only 29.62% of cells were arrested in S-phase with standard swainsonine at 48 h, suggesting the comprehensive action of certain other metabolites sharing the similar paradigm of antiproliferative properties in Metarhizium broth extract.

Galectin-1-mediated cell adhesion, invasion and cell death in human anaplastic large cell lymphoma: regulatory roles of cell surface glycans.

Galectin-1 is known to be one of the extracellular matrix proteins. To elucidate the biological roles of galectin-1 in cell adhesion and invasion of human anaplastic large cell lymphoma, we performed cell adhesion and invasion assays using the anaplastic large cell lymphoma cell line H-ALCL, which was previously established in our laboratory. From the cell surface lectin array, treatment with neuraminidase from Arthrobacter ureafaciens which cleaves all linkage types of cell surface sialic acid enhanced Arachis hypogaea (PNA), Helix pomatia (HPA) and Phaseolus vulgaris-L (L-PHA) lectin binding reactivity to cell surface of lymphoma cells suggesting that neuraminidase removes cell surface sialic acid. In cell adhesion and invasion assays treatment with neuraminidase markedly enhanced cell adhesion to galectin-1 and decreased cell invasive capacity through galectin-1. α2,6-linked sialic acid may be involved in masking the effect of the interaction between galectin-1 and cell surface glycans. H-ALCL cells expressed the ß-galactoside-α2,6-sialyltransferase ST6Gal1. On resialylation assay by recombinant ST6Gal1 with CMP-Neu5Ac, α2,6-resialylation of L-PHA reactive oligosaccharide by ST6Gal1 resulted in inhibition of H-ALCL cell adhesion to galectin-1 compared to the desialylated H-ALCL cells. On knockdown experiments, knockdown of ST6Gal1 dramatically enhanced cell adhesion to galectin-1. N-glycosylation inhibitor swainsonine treatment resulted in enhancement of cell adhesion to galectin-1. In glycomic analysis using the lectin blocking assay treatment with PNA, Artocarpus integrifolia (Jacalin), Glycine max (SBA), Helix pomatia (HPA), Vicia villosa (VVA), Ulex europaeus (UEA-1), Triticum vulgaris (WGA), Canavalia ensiformis (ConA), Phaseolus vulgaris-L (L-PHA), Phaseolus vulgaris-E4 (E-PHA), Datura stramonium (DSA) lectins resulted in modulation of lymphoma cell to galectin-1 suggesting that several types of glycans may regulate cell adhesion to galectin-1 by steric hindrance. The adhesive capacity of H-ALCL cells is regulated by phosphatidylinositol 3 phosphate kinase (PI3K) and actin cytoskeleton, and the invasive capacity of H-ALCL cells is regulated by PI3K, mitogen-activated protein kinase (MAPK), Rho and actin cytoskeleton. Furthermore, galectin-1-induced cell death in H-ALCL cells was accompanied by inhibition of CD45 protein tyrosine phosphatase (PTP) activity. In conclusion, cell adhesion and invasion to galectin-1 appeared to be regulated by cell surface sialylation and N-glycosylation, and galectin-1 regulates cell death through inhibition of CD45 PTP activity of H-ALCL.

The study of the Oxytropis kansuensis-induced apoptotic pathway in the cerebrum of SD rats.

BACKGROUND: Locoweeds cause significant livestock poisoning and economic loss all over the world. Animals can develop locoism, a chronic neurological disease, after grazing on locoweeds. Oxytropis kansuensis is a variety of locoweed that contains swainsonine as its main toxic ingredient. The purpose of this study was to investigate the apoptotic pathway induced in the cerebrum by swainsonine. RESULTS: Twenty-four Sprague-Dawley rats were randomly divided into four groups (experimental groups I, II, III and a control group) and 6 SD rats of each group were feed in 3 cages separately. Rats were penned as groups and fed with feeds containing 15% (SW content 0.03‰), 30% (SW content 0.06‰), or 45% (SW content 0.09‰) O. kansuensis for experimental groups I, II, and III, respectively, or complete feed in the case of the control group. One hundred and nineteen days after poisoning, and all rats showed neurological disorders at different degrees, which were considered to be successful established a chronic poisoning model of O. kansuensis. rats were sacrificed and the expression of Fas, FasL, Bcl-2, Bax as well as cleaved caspase-3, -8 and -9 proteins in brain tissues were detected by Western blot. The results showed that SW treatment up-regulated Fas and Fas ligand (FasL) (P < 0.05), and that there was an increase in Bax and a decrease in Bcl-2 protein (P < 0.01). Moreover, SW treatment significantly increases the activation of caspase-3, 8 and -9, the key effectors in apoptosis pathway (P < 0.01). CONCLUSION: Our data suggest that SW induces apoptosis in cells of the brain through death receptor and mitochondria-mediated, caspase-dependent apoptotic pathways in the brain tissue of SD rats.