Gal-3 plays an important pro-inflammatory role in the induction phase of acute colitis by promoting activation of NLRP3 inflammasome and production of IL-β in macrophages

BACKGROUND AND AIMS: Galectin-3 [Gal-3] is an endogenous lectin with a broad spectrum of immunoregulatory effects: it plays an important role in autoimmune/inflammatory and malignant diseases, but the precise role of Gal-3 in pathogenesis of ulcerative colitis is still unknown. METHODS: We used a model of dextran sulphate sodium [DSS]-induced acute colitis. The role of Gal-3 in pathogenesis of this disease was tested by evaluating disease development in Gal-3 deficient mice and administration of Gal-3 inhibitor. Disease was monitored by clinical, histological, histochemical, and immunophenotypic investigations. Adoptive transfer was used to detect cellular events in pathogenesis. RESULTS: Genetic deletion or pharmacological inhibition of Gal-3 significantly attenuate DSS-induced colitis. Gal-3 deletion suppresses production of pro-inflammatory cytokines in colonic macrophages and favours their alternative activation, as well as significantly reducing activation of NOD-like receptor family, pyrin domain containing 3 [NLRP3] inflammasome in macrophages. Peritoneal macrophages isolated from untreated Gal-3(-/-) mice and treated in vitro with bacterial lipopolysaccharide or DSS produce lower amounts of tumour necrosis factor alpha [TNF-α] and interleukin beta [IL-1β] when compared with wild type [WT] cells. Genetic deletion of Gal-3 did not directly affect total neutrophils, inflammatory dendritic cells [DCs] or natural killer [NK] T cells. However, the total number of CD11c+ CD80+ DCs which produce pro-inflammatory cytokines, as well as TNF-α and IL-1β producing CD45+ CD11c- Ly6G+ neutrophils were significantly lower in colons of Gal-3(-/-) DSS-treated mice. Adoptive transfer of WT macrophages significantly enhanced the severity of disease in Gal-3(-/-) mice. CONCLUSIONS: Gal-3 expression promotes acute DSS-induced colitis and plays an important pro-inflammatory role in the induction phase of colitis by promoting the activation of NLRP3 inflammasome and production of IL-1β in macrophages

Marrubium vulgare ethanolic extract induces proliferation block, apoptosis, and cytoprotective autophagy in cancer cells in vitro

Marrubium vulgare is a European medicinal plant with numerous beneficial effects on human health. The aim of the study was to isolate the plant ethanolic extract (MVE) and to investigate its anti-melanoma and anti-glioma effects. MVE was prepared by the modified pharmacopoeial percolation method and characterized by UHPLC-LTQ OrbiTrap MS. MVE dose-dependently reduced viability of melanoma (B16) and glioma (U251) cells, but not peripheral blood mononuclear cells. It arrested cell cycle in S+G2/M phase, which was associated with the activation of MAP kinase p38 and up-regulation of antiproliferative genes p53, p21 and p27. MVE induced oxidative stress, while antioxidants abrogated its antitumor effect. Furthermore, MVE induced mitochondrial depolarization, activation of caspase-9 and -3, Parp cleavage, phosphatidylserine exposure and DNA fragmentation. The mitochondrial apoptotic pathway was associated with the up-regulation of proapoptotic genes Pten, Bak1, Apaf1, and Puma and down-regulation of antiapoptotic genes survivin and Xiap. MVE also stimulated the expression of autophagy-related genes Atg5, Atg7, Atg12, Beclin-1, Gabarab and Sqstm1, as well as LC3-I conversion to the autophagosome associated LC3-II, while autophagy inhibitors exacerbated its cytotoxicity. Finally, the most abundant phenolic components of MVE, ferulic, p-hydroxybenzoic, caffeic and chlorogenic acids, did not exert a profound effect on viability of tumor cells, suggesting that other components individually or in concert are the mediators of the extracts' cytotoxicity. By demonstrating the ability of MVE to inhibit proliferation, induce apoptosis and cytoprotective autophagy, our results suggest that MVE, alone or combined with autophagy inhibitors, could be a good candidate for anti-melanoma and anti-glioma therapy

c-Jun N-terminal kinase-dependent apoptotic photocytotoxicity of solvent exchange-prepared curcumin nanoparticles

Indian spice curcumin is known for its anticancer properties, but the anticancer mechanisms of nanoparticulate curcumin have not been completely elucidated. We here investigated the in vitro anticancer effect of blue light (470 nm, 1 W)-irradiated curcumin nanoparticles prepared by tetrahydrofuran/water solvent exchange, using U251 glioma, B16 melanoma, and H460 lung cancer cells as targets. The size of curcumin nanocrystals was approximately 250 nm, while photoexcitation induced their oxidation and partial agglomeration. Although cell membrane in the absence of light was almost impermeable to curcumin nanoparticles, photoexcitation stimulated their internalization. While irradiation with blue light (1-8 min) or nanocurcumin (1.25-10 mu g/ml) alone was only marginally toxic to tumor cells, photoexcited nanocurcumin displayed a significant cytotoxicity depending both on the irradiation time and nanocurcumin concentration. Photoexcited nanocurcumin induced phosphorylation of cJun N-terminal kinase (JNK), mitochondrial depolarization, caspase-3 activation, and cleavage of poly (ADP-ribose) polymerase, indicating apoptotic cell death. Accordingly, pharmacologial inhibition of JNK and caspase activity rescued cancer cells from photoexcited nanocurcumin. On the other hand, antioxidant treatment did not reduce photocytotoxicity of nanocurcumin, arguing against the involvement of oxidative stress. By demonstrating the ability of photoexcited nanocurcumin to induce oxidative-stress independent, JNK-and caspase-dependent apoptosis, our results support its further investigation in cancer therapy