Discovery of novel selenium-containing azole derivatives as antifungal agents by exploiting the hydrophobic cleft of CYP51.

Herein, we report the design, synthesis and evaluation of a novel series of diselenide and selenide derivatives as potent antifungal agents by exploiting the hydrophobic cleft of CYP51. Among all synthesized compounds, the most potent compound B01 with low cytotoxic and hemolysis effect exhibited excellent activity against C.alb., C.gla., C.par. and C.kru., as well as selected fluconazole-resistant strains. Moreover, compound B01 could reduce the biofilm formation of the FCZ-resistant C.alb. Subsequently, metabolic stability assays using liver microsomes demonstrated that compound B01 showed good profiles of metabolic stability. With superior pharmacological profile, compound B01 was advanced into in vivo bioactivity evaluation. In a murine model of systemic C.alb. infection, compound B01 significantly reduced fungal load of kidneys. Furthermore, compound B01 revealed relatively low acute toxicity and subacute toxicity in mice. In addition, docking study performed into C.alb. CYP51, showed the binding mode between C.alb. CYP51 and compound B01. Collectively, diselenides compound B01 can be further developed for the potential treatment of invasive fungal infections.

Lead optimization generates selenium-containing miconazole CYP51 inhibitors with improved pharmacological profile for the treatment of fungal infections.

A series of selenium-containing miconazole derivatives were identified as potent antifungal drugs in our previous study. Representative compound A03 (MIC = 0.01 µg/mL against C.alb. 5314) proved efficacious in inhibiting the growth of fungal pathogens. However, further study showed lead compound A03 exhibited potential hemolysis, significant cytotoxic effect and unfavorable metabolic stability and was therefore modified to overcome these drawbacks. In this article, the further optimization of selenium-containing miconazole derivatives resulted in the discovery of similarly potent compound B17 (MIC = 0.02 µg/mL against C.alb. 5314), exhibiting a superior pharmacological profile with decreased rate of metabolism, cytotoxic effect and hemolysis. Furthermore, compound B17 showed fungicidal activity against Candida albicans and significant effects on the treatment of resistant Candida albicans infections. Meanwhile, compound B17 not only could reduce the ergosterol biosynthesis pathway by inhibiting CYP51, but also inhibited biofilm formation. More importantly, compound B17 also shows promising in vivo efficacy after intraperitoneal injection and the PK study of compound B17 was evaluated. In addition, molecular docking studies provide a model for the interaction between the compound B17 and the CYP51 protein. Overall, we believe that these selenium-containing miconazole compounds can be further developed for the potential treatment of fungal infections.

Oligomer procyanidins (F2) isolated from grape seeds inhibits tumor angiogenesis and cell invasion by targeting HIF-1α in vitro.

Overexpression of hypoxia-inducible factor-1 (HIF-1) α, a transcription factor which immortalizes tumors by inducing expression of the genes involved in cell survival, migration and angiogenesis, is closely associated with poor prognosis, increased risk of metastasis and increased mortality. Oligomer procyanidins (F2), a natural fraction from grape seeds, has been demonstrated to have antioxidant and antitumor activities, however the antitumor effect of F2 targeting HIF-1α remains unknown. The present study showed that F2 markedly decreased HIF-1α and the expression of its target genes in cancer cells through inactivating the EGFR-PI3K-AKT-mTOR and MAPK-ERK1/2 pathways. Moreover, F2 suppressed vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 expressions, followed by the inhibition of tumor angiogenesis and cell invasion in a HIF-1α-dependent manner. Collectively, these findings indicate that the antitumor effect of F2 is, at least in part, mediated by suppressing HIF-1α-dependent pathway, and suggest that F2 may be a potentially useful agent for treatment of human cancer.

Anti-tumor activity of three novel derivatives of ginsenoside on colorectal cancer cells.

25-Hydroxyprotopanaxadiol (25-OH-PPD) is a natural compound isolated from Panax ginseng, and its anti-tumor activity has been studied in previous publication. In the current study, we investigated the anti-tumor activity of three novel derivatives synthesized from 25-OH-PPD, namely (20R)-12ß-O-(l-chloracetyl)-dammarane-3ß, 20, 25-triol (xl), (20R)-3ß-O-(l-alanyl)-dammarane-12ß, 20, 25-triol (1c), and (20R)-3ß-O-(Boc-l-arginyl)-dammarane-12ß, 20, 25-triol (8b). All three compounds significantly inhibited the growths of human colorectal cancer cells, while having lesser effect on the growth of normal primary muscle cells and spleno-lymphocytes. Further mechanistic study demonstrated that these compounds could induce apoptosis by activating the components of caspase-signaling pathways in HCT116 cells, but not in spleno-lymphocytes. Taken together, the results suggested that 25-OH-PPD derivatives exerted promising anti-tumor activity that is specific to human colorectal cancer cells, and may therefore represent a potential chemotherapeutic strategy for the treatment of colorectal cancer.

Inhibition of ß-catenin signaling involved in the biological activities of a lignan E2S isolated from Carya cathayensis fruits.

Carya cathayensis is a fruit-bearing plant that belongs to the Juglandaceae family and is widely distributed throughout the world. It possesses various important biological activities. We have previously isolated an antitumor compound from the shell of C. cathayensis fruits and named it E2S ((E)-3-[(2S,3R)-2,3-dihydro-2-(4'-hydroxy-3'-methoxyphenyl)-3-hydroxymethyl-7-methoxy-1-benzo[b]furan-5-yl]-2-propenal). In this study, we investigated the antitumor activity of E2S against various human colorectal cancer cell lines (HCT116, HT29, SW480, LoVo). The results showed that E2S could significantly inhibit the growth of cancer cells in a dose-dependent manner, as well as disrupt the progression of the cell cycle. Mechanistic study revealed that E2S could decrease the protein levels of ß-catenin and its downstream targets (such as c-myc, a key transcriptional target of ß-catenin) in the cells. In addition, it also significantly suppressed ß-catenin/TCF transcriptional activity. Taken together, the results suggested that E2S might partially exert an antiproliferative effect on human colorectal cancer cells by targeting ß-catenin signaling, a finding that might potentially translate into a chemotherapeutic strategy for the treatment of cancer. It might also have implications for cancer prevention strategies.

Oligomer procyanidins from grape seeds induce a paraptosis-like programmed cell death in human glioblastoma U-87 cells.

CONTEXT: We recently reported that F2, an oligomer procyanidin fraction isolated from grape seeds, triggered an original form of cell death in U-87 human glioblastoma cells with a phenotype resembling morphological characteristics of paraptosis. However, the specific death mode induced by F2 and the mechanism of its action have not been assessed so far. OBJECTIVE: In the present work, we therefore further investigated the death mode of human glioblastoma cells induced by F2 and gained insight into the nature of the signaling pathways activated by F2 in glioblastoma cells. MATERIALS AND METHODS: Cell viability assay using MTT, (AO/EB) double staining, Western blot analysis, and Ca2+ assay using fura-2. RESULTS: Morphology studies revealed extensive cytoplasmic vacuolization in dying cells and no apoptotic body formation, membrane bleb formation, or nuclear fragmentation, though some was accompanied by MAPK activation and new protein synthesis, and was independent of caspase activation. Moreover, we demonstrated the involvement of calcium mobilization in F2-induced U-87 cell signaling. DISCUSSION AND CONCLUSION: Altogether we showed that F2 induced a kind of cell death resembling paraptosis in U-87 cells. The current report complements previous studies on the characterization of F2-induced U-87 cell death, enhances our understanding of the action mechanism of F2 on glioma, and helps in the development of novel antitumor therapeutics.

Inhibition of U-87 human glioblastoma cell proliferation and formyl peptide receptor function by oligomer procyanidins (F2) isolated from grape seeds.

Gliomas are the most common and lethal tumor type in the brain. The present study investigated the effect of oligomer procyanidins (F2) (F2, degree of polymerization 2-15), a natural fraction isolated from grape seeds on the biological behavior of glioblastoma cells. We found that F2 significantly inhibited the glioblastoma growth, with little cytotoxicity on normal cells, induced G2/M arrest and decreased mitochondrial membrane potential in U-87 cells. It also induced a non-apoptotic cell death phenotype resembling paraptosis in U-87 cells. In addition, it was found for the first time that F2 in non-cytotoxic concentrations selectively inhibited U-87 cell chemotaxis mediated by a G-protein coupled receptor formyl peptide receptor FPR, which is implicated in tumor cell invasion and metastasis. Further experiments indicated that F2 inhibited fMLF-induced U-87 cell calcium mobilization and MAP kinases ERK1/2 phosphorylation. Moreover, F2 attenuated the glioblastoma FPR expression, a new molecular target for glioma therapeutics, which has been shown to play important roles in glioma cells chemotaxis, proliferation and angiogenesis in addition to its promotion to tumor progression, but did not affect FPR mRNA expression in U-87 cells. Taken together, our results suggest that F2 may be a promising candidate for the development of novel anti-tumor therapeutics.