Search results for "boronic acid"

Hsp72 controls bortezomib-induced HepG2 cell death via interaction with pro-apoptotic factors.

2007

The proteasome inhibitor bortezomib is an efficacious inducer of apoptosis in the hepatoma HepG2 cell line. This study shows that bortezomib increased in these cells the level of the survival factor Hsp72 in a time- and dose-dependent manner. In a first phase of treatment, Hsp72 rapidly increased so that at 24 h of incubation with 50 nM bortezomib its level was approximately five-fold higher than the control. In this phase Hsp72 seemed to play a role in preventing HepG2 cell death, since it interacted with and sequestered the pro-apoptotic factors p53, AIF, Bax and Apaf-1. During a second day of treatment, although the nuclear levels of Hsp72, p53 and AIF increased, the interaction of Hsp72…

JNK and AP-1 mediate apoptosis induced by bortezomib in HepG2 cells via FasL/caspase-8 and mitochondria-dependent pathways

2006

The proteasome inhibitor bortezomib is an efficacious apoptotic agent in many tumor cells. This paper shows that bortezomib induced apoptosis in human hepatoma HepG2 cells associated with many modifications in the expression of survival or death factors. Although bortezomib increased the level of the protective factors HSP70 and HSP27, the effects of the drug that favour cell death were predominant. These events include accumulation of c-Jun, phospho-c-Jun and p53; increase in FasL level with activation of caspase-8; changes related to members of Bcl-2 family with increase in the level of pro-apoptotic members and decrease in that of anti-apoptotic ones; dissipation of mitochondrial potenti…

A Colorimetric Probe for the Selective Detection of Norepinephrine Based on a Double Molecular Recognition with Functionalized Gold Nanoparticles

2019

[EN] A simple colorimetric probe for the selective and sensitive detection of neurotransmitter norepinephrine (NE), an important biomarker in the detection of tumors such as pheochromocytoma and paraganglioma, is described. The sensing strategy is based on the use of spherical gold nanoparticles functionalized with benzaldehyde and boronic acid-terminated moieties. A double molecular recognition involving on one hand the aromatic aldehyde and the aminoalcohol group of NE, and on the other hand the boronic acid and the catechol moiety of the neurotransmitter, results in analyte triggered aggregation of the gold nanoparticles, leading to a bathochromic shift of the SPR band in the UV-vis spec…

Boronic Acids of Pharmaceutical Importance Affect the Growth and Photosynthetic Apparatus of Cyanobacteria in a Dose-Dependent Manner

2020

The dynamic increase in the commercial application of antimicrobial derivatives of boronic acids, and potential impact of their presence in aquatic systems, supports the necessity to study the toxicity of these substances towards microorganisms of crucial meaning in the environment. One example of the mentioned derivatives is tavaborole (5-fluoro-substituted benzoxaborole), a pharmaceutical agent with antifungal activity. Cyanobacteria were used as model organisms, which are photoautotrophic prokaryotes, as representative aquatic bacteria and photoautotrophs associated with the plant kingdom. To the best of our knowledge, we investigated this issue for the first time. In order to recognize …

Bortezomib induces in HepG2 cells IkappaBalpha degradation mediated by caspase-8.

2006

The present paper demonstrates that the proteasome inhibitor bortezomib, which behaves as an apoptotic agent in hepatoma HepG2 cells, caused in these cells a decrease in IkappaBalpha level and a consequent increase in NF- kappaB activity. The effect already appeared at 4 h of treatment and preceded the onset of apoptosis which was observed at 24 h. Our results demonstrate that bortezomib-induced IkappaBalpha degradation occurred in conjunction with the activation of caspase-8; moreover, the decrease in IkappaBalpha level was prevented in a dose-dependent manner by the addition of z-IETD, a specific inhibitor of caspase-8. Bortezomib caused the same effects in non-tumor Chang liver cells, wh…

Targeting apoptosis in solid tumors: the role of bortezomib from preclinical to clinical evidence.

2007

The ubiquitin-proteasome pathway is the main proteolytic system present in the nucleus and cytoplasm of all eukaryotic cells. Apoptosis activation induced by ubiquitin-proteasome pathway inhibition makes the proteasome a new target of anticancer therapy. Bortezomib is the first proteasome inhibitor to be approved by the US FDA; in 2003 as a third line and in 2005 as a second line therapy for the treatment of multiple myeloma only. This review focuses on the use of bortezomib, not only in its therapeutic role but also, more specifically, in its biologic role and discusses the most recent applications of the drug in solid tumors, both at a preclinical and clinical level.

RETRACTED: trans-Tetrakis(pyridine)dichloroiron(II) as catalyst for Suzuki cross-coupling in ethanol and water

2008

Aryl bromides can be coupled with phenylboronic acid in moderate to excellent yields using a transtetrakis(pyridine)dichloroiron(II) catalyst. The Suzuki–Miyaura reaction can be carried out under air in ethanol and aqueous ethanol with low catalyst loading. Addition of TBAB dramatically increases the yields in aqueous ethanol or in water. trans-Tetrakis(pyridine)dichloroiron(II) offers an environmental and less expensive method for the synthesis of biaryl compounds. This is the first example of an iron– pyridine catalyst for Suzuki cross-coupling.

A Three-Component Palladium-Catalyzed Oxidative CC Coupling Reaction: A Domino Process in Two Dimensions

2013

Highly Loaded Multi-Walled Carbon Nanotubes Non-Covalently Modified with a Bis-Imidazolium Salt and their Use as Catalyst Supports

2016

The surfaces of multi-walled carbon nanotubes (MWCNTs) were non-covalently modified using two bis-imidazolium dibromide derivatives having phenyl or pyrene groups. Due to the presence of the two pyrene groups the bis(pyren-1-ylmethylimidazolium) dibromide derivative was immobilised at a loading of about 15-16 wt %, whereas only <3 wt % of the phenyl derivative was immobilised. The presence of the two imidazolium cations helped the immobilisation of tetrachloropalladate ions after exchange with bromide ions. Tetrachloropalladate was used as pre-catalyst in several Suzuki-Miyaura carbon-carbon cross-coupling reactions in water or water/ethanol at 50 °C in only 0.1 mol % and compared with the …

Multiple Myeloma Treatment in Real-world Clinical Practice: Results of a Prospective, Multinational, Noninterventional Study.

2018

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