Background/Objectives: Drug resistance (DR) is a major challenge in cancer therapy, contributing to approximately 90% of cancer-related deaths. While alterations drug metabolism are known be key drivers DR, their role-particularly the early stages acquired chemoresistance-remains understudied. Phase I drug-metabolizing enzymes (DMEs), especially cytochrome P450s (CYPs), significantly influence metabolic fate chemotherapeutic agents, directly affecting response. This study aimed investigate...

Eugenol (1-allyl-3-methoxy-4-hydroxybenzene; CAS No. 97-53-0), a compound extracted from clove oil and marjoram, is widely used as food flavouring substance present in spices such basil, cinnamon nutmeg. It also dentistry an antiseptic analgesic. Structural similarities with the class IIB IARC carcinogen safrole raises questions on its putative carcinogenicity. We evaluated genotoxicity of eugenol V79 cells using chromosomal aberrations (CAs), without rat liver biotransformation (S9)....

Patients with congenital adrenal hyperplasia, exhibiting combined CYP17 and CYP21 deficiency, were shown by Arlt et al. (2004) to harbor a 541T→G mutation in exon 5 of <i>POR</i> (encoding NADPH-cytochrome P450 reductase, CYPOR), which resulted Y181D substitution that obliterated electron transfer capacity. Using bacterial expression models, we examined catalytic physical properties the human CYPOR variant. As purified, lacked flavin mononucleotide (FMN) <i>c</i> reductase (NCR) activity but...

The altered activity of drug metabolism enzymes (DMEs) is a hallmark chemotherapy resistance. Cytochrome P450s (CYPs), mainly CYP3A4, and several oxidoreductases are responsible for Phase I doxorubicin (DOX), an anthracycline widely used in breast cancer (BC) treatment. This study aimed to investigate the role DMEs involved first stages acquisition DOX-resistance BC cells. For this purpose, expression 92 DME genes specific CYP-complex activities were assessed either sensitive (MCF-7 parental...

Considering the increase in production and use of nanomaterials (NM) food/feed food contact materials, novel strategies for efficient sustainable hazard characterization, especially early stages NM development, have been proposed. Some these encompass utilization vitro simulated digestion prior to cytotoxic genotoxic assessment. This entails exposing fluids that replicate three successive phases digestion: oral, gastric, intestinal. Subsequently, resulting products are added models...

Human NADPH-cytochrome P450 oxidoreductase (POR) gene mutations are associated with severe skeletal deformities and disordered steroidogenesis. The human POR mutation A287P presents sexual development malformations. Difficult recombinant expression purification of this mutant suggested that the protein was less stable than WT. activities cytochrome 17A1, 19A1, 21A2, critical in steroidogenesis, were similar using our purified, full-length, unmodified or WT POR, as those several...

NADPH cytochrome P450 oxidoreductase (CPR) is the obligatory electron supplier in sustaining activity of microsomal (CYP). The variant nature isoform specific proximal interface CYPs implies that CPR capable multiple degenerated interactions with for transfer, through different binding mechanisms, which are still not well understood. Recently, we showed dynamics allows formation open conformers can be sampled by its structurally diverse redox partners a CYP-isoform dependent manner. To...

NADPH-cytochrome P450 oxidoreductase (CYPOR) variants have been described in patients with perturbed steroidogenesis and sexual differentiation, related to Antley-Bixler syndrome (ABS). It is important determine the effect of these on CYP3A4, major drug-metabolizing cytochrome (P450) humans. In this study, 12 CYPOR_ABS were separately coexpressed CYP3A4 a robust vitro system evaluate effects activity milieu that recapitulates stoichiometry mammalian systems. Full-length CYPOR resulting...

Adequate alternatives to conventional animal testing are needed study developmental neurotoxicity (DNT). Here, we used kinematic analysis assess DNT of known (toluene (TOL) and chlorpyrifos (CPS)) putative (β-N-methylamino-L-alanine (BMAA)) neurotoxic compounds. Drosophila melanogaster was exposed these compounds during development evaluated for survival adult parameters using the FlyWalker system, a kinematics evaluation method. At concentrations that do not induce general toxicity, solvent...

In this study we describe the development of strain BMX100, a new Escherichia coli K12 tester strain, derived from MX100, which was constructed for detection mutagens and mechanistic studies chemical carcinogens. We demonstrate here that BMX100 can be used stable expression human CYP1A2 or fused to rat liver NADPH cytochrome P450 reductase. Mutagenicity precarcinogens known bioactivated by CYP1A2, namely 2-aminoanthracene (2-AA), aflatoxin Bl (AFB1) 2-amino-3-methylimidazo[4,5-f]quinoline...

NADPH-cytochrome P450 reductase (CPR) is a redox partner of microsomal cytochrome P450s and prototype the diflavin family. CPR contains 3 distinct functional domains: FMN-binding domain (acceptor reduction), linker (hinge), connecting/FAD (NADPH oxidation). It has been demonstrated that mechanism exhibits an important step in which it switches from compact, closed conformation (locked state) to ensemble open conformations (unlocked state), latter enabling electron transfer partners. The...

A unique cytochrome P450 (CYP) oxidoreductase (CPR) sustains activities of human microsomal CYPs. Its function requires toggling between a closed conformation enabling electron transfers from NADPH to FAD and then FMN cofactors open conformations forming complexes transferring electrons We previously demonstrated that distinct features the hinge region linking domain (FD) modulate conformer poses their interactions with Specific FD residues contribute in CYP isoform-dependent manner...

Background Interindividual variability in cytochrome P450 (CYP)-mediated xenobiotic metabolism is extensive. CYP requires two electrons, which can be donated by NADPH oxidoreductase (CYPOR) and/or b5 (b5). Although substantial number of studies have reported on the function and effect CYP-mediated catalysis, its mode action still not fully understood. Objective The aim this work was to examine activities eight natural-occurring variants human CYP1A2, namely, T83M, S212C, S298R, G299S, I314V,...

NADPH-cytochrome P450 reductase (CPR) is the unique redox partner of microsomal cytochrome P450s (CYPs). CPR exists in a conformational equilibrium between open and closed conformations throughout its electron transfer (ET) function. Previously, we have shown that electrostatic flexibility properties hinge segment are critical for ET. Three mutants human were studied (S243P, I245P R246A) combined with representative drug-metabolizing CYPs (isoforms 1A2, 2A6 3A4). To probe effect these...

Cytochrome b5 (b5) is increasingly recognized to be of importance for specific cytochrome P450 (CYP) activities. We developed human b5/CYP-competent mutagenicity tester bacteria study the role in bioactivation activity CYP. These new were derived from previously engineered CYP-competent Escherichia coli K12 strain MTC, containing a bi-plasmid system co-expression CYP form (CYP1A2, 2A6 or 2E1) with b5, and NADPH reductase (RED), resulting BTC-b5-1A2, BTC-b5-2A6 BTC-b5-2E1, respectively. The...

Conjugation of fluorescent dyes to proteins-a prerequisite for the study conformational dynamics by single-molecule (sm) FRET-can lead substantial changes in a dye's photophysical properties, ultimately biasing determination inter-dye distances. In particular, cyanine and their derivatives, most commonly used smFRET experiments, exhibit such behavior. To overcome this, we developed general strategy equip proteins site-specifically with FRET pairs through chemoselective reactions two distinct...