Tyrosinase is a multifunctional, glycosylated, and copper-containing oxidase, which catalyzes the first two steps in mammalian melanogenesis and is responsible for enzymatic browning reactions in ...damaged fruits during post-harvest handling and processing. Neither hyperpigmentation in human skin nor enzymatic browning in fruits are desirable. These phenomena have encouraged researchers to seek new potent tyrosinase inhibitors for use in foods and cosmetics. This article surveys tyrosinase inhibitors newly discovered from natural and synthetic sources. The inhibitory strength is compared with that of a standard inhibitor, kojic acid, and their inhibitory mechanisms are discussed.
Melanogenesis is a biosynthetic pathway for the formation of the pigment melanin in human skin. A key enzyme, tyrosinase, catalyzes the first and only rate-limiting steps in melanogenesis, and the ...down-regulation of enzyme activity is the most reported method for the inhibition of melanogenesis. Because of the cosmetically important issue of hyperpigmentation, there is a big demand for melanogenesis inhibitors. This encourages researchers to seek potent melanogenesis inhibitors for cosmetic uses. This article reviews melanogenesis inhibitors that have been recently discovered from natural sources. The reaction mechanisms of the inhibitors on tyrosinase activity are also discussed.
In 2008, sorafenib became the first approved systemic therapeutic agent for advanced HCC. Although its pharmacological efficacy has been established, reimbursement for such a new, high‐cost drug, as ...well as physicians' awareness and prescription practice, likewise contribute to its clinical effectiveness. We therefore conducted a retrospective study using 38 sorafenib‐eligible, advanced HCC patients when sorafenib was approved but not yet reimbursed as a control and 216 patients during the reimbursed era. Study group showed longer survival at 8.2 months versus the control's 4.9 months (p = 0.0063 hazard ratio: 0.612 0.431 ~ 0.868, p = 0.0059). Among the 42 (19.4%) patients who survived more than 2 years, 50% had tumor rupture, and all 32 patients with portal vein tumor thrombus and/or extrahepatic metastasis received sorafenib (p = 0.003). Furthermore, during their first 2 years of HCC management, sorafenib had been given in 29.1% of the treatment courses among survivors between 2 and 5 years while it was prescribed in 55.8% among the more than 5 years survivor group (p < 0.001). In conclusion, survival of sorafenib‐eligible HCC patients significantly improved after reimbursement. Patients who underwent longer sorafenib treatment had a survival advantage, except for those with tumor rupture. Reimbursement and awareness of prescriptions for a newly introduced medication therefore improve clinical effectiveness.
The inflammatory cytokine interleukin-6 (IL-6) is critical for the expression of octamer-binding transcription factor 4 (OCT4), which is highly associated with early tumor recurrence and poor ...prognosis of hepatocellular carcinomas (HCC). DNA methyltransferase (DNMT) family is closely linked with OCT4 expression and drug resistance. However, the underlying mechanism regarding the interplay between DNMTs and IL-6-induced OCT4 expression and the sorafenib resistance of HCC remains largely unclear.
HCC tissue samples were used to examine the association between DNMTs/OCT4 expression levels and clinical prognosis. Serum levels of IL-6 were detected using ELISA assays (n = 144). Gain- and loss-of-function experiments were performed in cell lines and mouse xenograft models to determine the underlying mechanism in vitro and in vivo.
We demonstrate that levels of DNA methyltransferase 3 beta (DNMT3b) are significantly correlated with the OCT4 levels in HCC tissues (n = 144), and the OCT4 expression levels are positively associated with the serum IL-6 levels. Higher levels of IL-6, DNMT3b, or OCT4 predicted early HCC recurrence and poor prognosis. We show that IL-6/STAT3 activation increases DNMT3b/1 and OCT4 in HCC. Activated phospho-STAT3 (STAT-Y640F) significantly increased DNMT3b/OCT4, while dominant negative phospho-STAT3 (STAT-Y705F) was suppressive. Inhibiting DNMT3b with RNA interference or nanaomycin A (a selective DNMT3b inhibitor) effectively suppressed the IL-6 or STAT-Y640F-induced increase of DNMT3b-OCT4 and ALDH activity in vitro and in vivo. The fact that OCT4 regulates the DNMT1 expressions were further demonstrated either by OCT4 forced expression or DNMT1 silence. Additionally, the DNMT3b silencing reduced the OCT4 expression in sorafenib-resistant Hep3B cells with or without IL-6 treatment. Notably, targeting DNMT3b with nanaomycin A significantly increased the cell sensitivity to sorafenib, with a synergistic combination index (CI) in sorafenib-resistant Hep3B cells.
The DNMT3b plays a critical role in the IL-6-mediated OCT4 expression and the drug sensitivity of sorafenib-resistant HCC. The p-STAT3 activation increases the DNMT3b/OCT4 which confers the tumor early recurrence and poor prognosis of HCC patients. Findings from this study highlight the significance of IL-6-DNMT3b-mediated OCT4 expressions in future therapeutic target for patients expressing cancer stemness-related properties or sorafenib resistance in HCC.
Real-world data on the effectiveness of glecaprevir/pibrentasvir (GLE/PIB) for patients with HCV infection and compensated cirrhosis is limited, especially for the 8-week regimen and in an Asian ...population. This retrospective study enrolled 159 consecutive patients with HCV and compensated cirrhosis who were treated with GLE/PIB at a single center in Taiwan. Sustained virological response (SVR) and adverse events (AEs) were evaluated. Among the 159 patients, 91 and 68 were treated with GLE/PIB for 8 and 12 weeks, respectively. In the per protocol analysis, both the 8- and 12-week groups achieved 100% SVR (87/87 vs. 64/64); and in the evaluable population analysis, 95.6% (87/91) of the 8-week group and 94.1% (64/68) of the 12-week group achieved SVR. The most commonly reported AEs, which included pruritus (15.4% vs. 26.5%), abdominal discomfort (9.9% vs. 5.9%), and skin rash (5.5% vs. 5.9%), were mild for the 8- and 12-week groups. Two patients in the 8-week group exhibited total bilirubin elevation over three times the upper normal limit. One of these two patients discontinued GLE/PIB treatment after 2 weeks but still achieved SVR. Both 8- and 12-week GLE/PIB treatments are safe and effective for patients of Taiwanese ethnicity with HCV and compensated cirrhosis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Daidzein and genistein are two major components of soy isoflavones. They exist abundantly in plants and possess multiple bioactivities. In contrast, ortho-hydroxydaidzein (OHD) and ...ortho-hydroxygenistein (OHG), including 6-hydroxydaidzein (6-OHD), 8-hydroxydaidzein (8-OHD), 3'-hydroxydaidzein (3'-OHD), 6-hydroxygenistein (6-OHG), 8-hydroxygenistein (8-OHG), and 3'-hydroxygenistein (3'-OHG), are rarely found in plants. Instead, they are usually isolated from fermented soybean foods or microbial fermentation broth feeding with soybean meal. Accordingly, the bioactivity of OHD and OHG has been investigated less compared to that of soy isoflavones. Recently, OHD and OHG were produced by genetically engineering microorganisms through gene cloning of cytochrome P450 (CYP) enzyme systems. This success opens up bioactivity investigation and industrial applications of OHD and OHG in the future. This article reviews isolation of OHD and OHG from non-synthetic sources and production of the compounds by genetically modified microorganisms. Several bioactivities, such as anticancer and antimelanogenesis-related activities, of OHD and OHG, are also discussed.
Abstract
Clinical trials showed pangenotypic direct-acting antivirals’ (DAAs) excellent efficacy and safety when treating hepatitis C virus (HCV). Two pangenotypic regimens were examined, ...glecaprevir/pibrentasvir (GLE/PIB) and sofosbuvir/velpatasvir (SOF/VEL), in a real-world Taiwanese setting, including all HCV patients treated with GLE/PIB or SOF/VEL from August 2018 to April 2020. The primary endpoint was sustained virologic response 12 weeks after treatment cessation (SVR12), including adverse events (AEs). A total of 1,356 HCV patients received pangenotypic DAA treatment during the study: 742 and 614 received GLE/PIB and SOF/VEL, respectively. The rates of SVR12 for GLE/PIB and SOF/VEL were 710/718 (98.9%) and 581/584 (99.5%), respectively, by per-protocol analysis, and 710/742 (95.7%) and 581/614 (94.6%), respectively, by evaluable population analysis. Eleven (GLE/PIB: 8, SOF/VEL: 3) did not achieve SVR12. The most common AEs for GLE/PIB and SOF/VEL were pruritus (17.4% vs. 2.9%), abdominal discomfort (5.8% vs. 4.4%), dizziness (4.2% vs. 2%), and malaise (3.1% vs. 2.9%). Laboratory abnormalities were uncommon; only < 1% exhibited elevated total bilirubin or aminotransferase levels with both regimens. Five drug discontinuations occurred due to AEs (bilirubin elevation: 3; dermatological issues: 2). Pangenotypic DAAs GLE/PIB and SOF/VEL are effective and well tolerated, achieving high SVR12 rates for patients with all HCV genotypes.
AsqJ, an iron(II)‐ and 2‐oxoglutarate‐dependent enzyme found in viridicatin‐type alkaloid biosynthetic pathways, catalyzes sequential desaturation and epoxidation to produce cyclopenins. Crystal ...structures of AsqJ bound to cyclopeptin and its C3 epimer are reported. Meanwhile, a detailed mechanistic study was carried out to decipher the desaturation mechanism. These findings suggest that a pathway involving hydrogen atom ion at the C10 position of the substrate by a short‐lived FeIV‐oxo species and the subsequent formation of a carbocation or a hydroxylated intermediate is preferred during AsqJ‐catalyzed desaturation.
Make it a double: The mechanism of the desaturation catalyzed by AsqJ, a non‐heme iron enzyme, was elucidated using a complementary approach including probe design, X‐ray crystallography, molecular dynamics simulations, and spectroscopic characterizations. Subsequent to primary C−H bond activation, a carbocation or a hydroxylated intermediate is likely to be involved in the desaturation.
Background
Pangenotypic direct‐acting antiviral agents (DAAs) glecaprevir/pibrentasvir (GLE/PIB) and sofosbuvir/velpatasvir (SOF/VEL) are effective against all hepatitis C virus (HCV) genotype ...infections. However, data on pangenotypic DAA treatment for mixed genotype HCV infection are sparse.
Methods
This is a retrospective, single site cohort study analyzing all patients with mixed HCV genotype infections treated with GLE/PIB or SOF/VEL from August 2018 to August 2020 in Chiayi Chang Gung Memorial Hospital, Taiwan. The primary study endpoint was sustained virologic response (SVR) 12 weeks after treatment cessation. We also reported adverse events (AEs).
Results
A total of 108 patients with mixed infections of any two or three genotypes of 1a, 1b, 2, 3, and 6 received pangenotypic DAAs during the study period. A total of 67 patients received GLE/PIB and 41 received SOF/VEL. The evaluable population analysis revealed SVR rates of 94% (63/67) and 95.1% (39/41) for GLE/PIB and SOF/VEL therapy, respectively, and the per‐protocol analysis revealed an SVR of 100% for both regimens. Four patients in the GLE/PIB group and two patients in the SOF/VEL were lost to follow‐up. The most common AEs for GLE/PIB versus SOF/VEL therapy included pruritus (14.9% vs 2.4%), fatigue (6.0% vs 7.3%), abdominal discomfort (4.5% vs 7.3%), and acid reflux (3.0% vs 4.9%). DAA‐related significant laboratory abnormalities occurred in three patients with > 1.5 × elevated bilirubin level in the GLE/PIB group. None of the above AEs resulted in DAA discontinuation.
Conclusions
Pangenotypic DAAs are well tolerated by and yield high SVR rates in patients with mixed genotype HCV infection.
Most cases of hepatocellular carcinoma (HCC) arise with the fibrotic microenvironment where hepatic stellate cells (HSCs) and carcinoma-associated fibroblasts (CAFs) are critical components in HCC ...progression. Therefore, CAF normalization could be a feasible therapy for HCC. Galectin-1 (Gal-1), a β-galactoside-binding lectin, is critical for HSC activation and liver fibrosis. However, few studies has evaluated the pathological role of Gal-1 in HCC stroma and its role in hepatic CAF is unclear. Here we showed that Gal-1 mainly expressed in HCC stroma, but not cancer cells. High expression of Gal-1 is correlated with CAF markers and poor prognoses of HCC patients. In co-culture systems, targeting Gal-1 in CAFs or HSCs, using small hairpin (sh)RNAs or an therapeutic inhibitor (LLS30), downregulated plasminogen activator inhibitor-2 (PAI-2) production which suppressed cancer stem-like cell properties and invasion ability of HCC in a paracrine manner. The Gal-1-targeting effect was mediated by increased a disintegrin and metalloprotease 17 (ADAM17)-dependent TNF-receptor 1 (TNFR1) shedding/cleavage which inhibited the TNF-α → JNK → c-Jun/ATF2 signaling axis of pro-inflammatory gene transcription. Silencing Gal-1 in CAFs inhibited CAF-augmented HCC progression and reprogrammed the CAF-mediated inflammatory responses in a co-injection xenograft model. Taken together, the findings uncover a crucial role of Gal-1 in CAFs that orchestrates an inflammatory CSC niche supporting HCC progression and demonstrate that targeting Gal-1 could be a potential therapy for fibrosis-related HCC.
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