Cytochrome P450-Mediated Biotransformation of Sorafenib and Its N-Oxide Metabolite: Implications for Cell Viability and Human Toxicity

Synthesis of Sorafenib-Ruthenium Complexes, Investigation of Biological Activities and Applications in Drug Delivery Systems as an Anticancer Agent

Sorafenib, a multiple kinase inhibitor, is widely used as a first-line treatment for hepatocellular carcinoma. However, there is a need for more effective alternatives when sorafenib proves insufficient. In this study, we aimed to design a structure that surpasses sorafenib's efficacy, leading us to synthesize sorafenib-ruthenium complexes for the first time and investigate their properties. Our results indicate that the sorafenib-ruthenium complexes exhibit superior epidermal growth factor receptor (EGFR) inhibition compared to sorafenib alone. Interestingly, among these complexes, Ru3S demonstrated high activity against various cancer cell lines including sorafenib-resistant HepG2 cells while exhibiting significantly lower cytotoxicity than sorafenib in healthy cell lines. Further evaluation of cell cycle, cell apoptosis, and antiangiogenic effects, molecular docking, and molecular dynamics studies revealed that Ru3S holds great potential as a drug candidate. Additionally, when free Ru3S was encapsulated into polymeric micelles M1, enhanced cytotoxicity on HepG2 cells was observed. Collectively, these findings position Ru3S as a promising candidate for EGFR inhibition and warrant further exploration for drug development purposes.

Detoxification of fluoroglucocorticoid by Acinetobacter pittii C3 via a novel defluorination pathway with hydrolysis, oxidation and reduction: Performance, genomic characteristics, and mechanism

Biological dehalogenation degradation was an important detoxification method for the ecotoxicity and teratogenic toxicity of fluorocorticosteroids (FGCs). The functional strain Acinetobacter pittii C3 can effectively biodegrade and defluorinate to 1 mg/L Triamcinolone acetonide (TA), a representative FGCs, with 86 % and 79 % removal proportion in 168 h with the biodegradation and detoxification kinetic constant of 0.031/h and 0.016/h. The dehalogenation and degradation ability of strain C3 was related to its dehalogenation genomic characteristics, which manifested in the functional gene expression of dehalogenation, degradation, and toxicity tolerance. Three detoxification mechanisms were positively correlated with defluorination pathways through hydrolysis, oxidation, and reduction, which were regulated by the expression of the haloacid dehalogenase (HAD) gene (mupP, yrfG, and gph), oxygenase gene (dmpA and catA), and reductase gene (nrdAB and TgnAB). Hydrolysis defluorination was the most critical way for TA detoxification metabolism, which could rapidly generate low-toxicity metabolites and reduce toxic bioaccumulation due to hydrolytic dehalogenase-induced defluorination. The mechanism of hydrolytic defluorination was that the active pocket of hydrolytic dehalogenase was matched well with the spatial structure of TA under the adjustment of the hydrogen bond, and thus induced molecular recognition to promote the catalytic hydrolytic degradation of various amino acid residues. This work provided an effective bioremediation method and mechanism for improving defluorination and detoxification performance.

The role of cytochrome P450 3A4-mediated metabolism in sorafenib and lapatinib hepatotoxicity

Tyrosine kinase inhibitors (TKIs) are increasingly popular drugs used to treat more than a dozen different diseases, including some forms of cancer. Despite having fewer adverse effects than traditional chemotherapies, they are not without risks. Liver injury is a particular concern. Of the FDA-approved TKIs, approximately 40% cause hepatotoxicity. However, little is known about the underlying pathophysiology. The leading hypothesis is that TKIs are converted by cytochrome P450 3A4 (CYP3A4) to reactive metabolites that damage proteins. Indeed, there is strong evidence for this bioactivation of TKIs in in vitro reactions. However, the actual toxic effects are underexplored. Here, we measured the cytotoxicity of several TKIs in primary mouse hepatocytes, HepaRG cells, and HepG2 cells with and without CYP3A4 modulation. To our surprise, the data indicate that CYP3A4 increases resistance to sorafenib and lapatinib hepatotoxicity. The results have implications for the mechanism of toxicity of these drugs in patients and underline the importance of selecting an appropriate experimental model.

A high throughput method for Monitoring of Sorafenib, regorafenib, cabozantinib and their metabolites with UPLC-MS/MS in rat plasma

As multi-targeted tyrosine kinase inhibitors, sorafenib, regorafenib and cabozantinib are widely used in hepatocellular carcinoma (HCC) for systemic therapies with anti-proliferative and anti-angiogenic effects. Nevertheless, adverse effects or insufficient efficacy appear frequently due to the plasma concentration with individual variability of these drugs. To ensure the curative effect and safety by therapeutic drug monitoring (TDM), this study developed a high throughput method to quantify sorafenib, regorafenib, cabozantinib and their active metabolites in plasma simultaneously. The chromatographic separation analysis achievement was performed on a Waters-ACQUITY UPLC BEH C18 column by UPLC-MS/MS system using a gradient elution of solvent A (acetonitrile) and solvent B (water with 0.1% formic acid) in 3.0 min. This method presented satisfactory results of specificity, precision (the intra-day coefficient of variation was between 2.5% and 6.6%, and the inter-day coefficient of variation was between 4.0% and 11.1%) and accuracy (within ±15% for intra-day and inter-day), as well as the stability under certain conditions, the matrix effect in plasma, and extraction recovery (75.6%–94.4%). The linearity of each analyte in the proper concentration scope indicated excellent. This study strictly complied with the performance rules of assay validation in biological medium proposed by FDA and was successfully applied to the pharmacokinetic study in rats. Thus, it would be an advantageous option to research the relationship between concentration-efficacy and concentration-toxic in HCC patients who were supposed to take these medications.

Herbacetin Broadly Blocks the Activities of CYP450s by Different Inhibitory Mechanisms

Herbacetin is a bioactive flavanol compound that has various pharmacological effects. However, the pharmacokinetic characteristics have not been thoroughly investigated. Previously, we screened a natural compound library and identified herbacetin as a potent CYP blocker. Herein, we aimed to mechanistically determine the inhibitory effects of herbacetin on CYP450 and its potential application. A human liver microsome incubation system was developed based on a UPLC-MS/MS method. Moreover, an in silico docking assay and a human CYP recombinase reaction system were developed and used to investigate binding affinity and inhibitory efficacy. Subsequently, the effects of the combination of herbacetin and sorafenib on HepG2 cells were assessed by MTT and immunoblotting assays. The concentration of sorafenib and its main metabolite were measured by UPLC-MS/MS after incubation with or without herbacetin. As a result, we found herbacetin almost completely inhibited the functions of major CYPs at 100 µM. Moreover, through analysis of the structure-activity relationship, we found 4-, 6-, and 8-hydroxyl were essential groups for the inhibitory effects. Herbacetin inhibited CYP3A4, CYP2B6, CYP2C9, and CYP2E1 in a mixed manner, but non-competitively blocked CYP2D6. These results are in good agreement with the recombinase reaction in vitro results, with an IC₅₀ < 10 µM for each tested isoenzyme. Interestingly, the stimulatory effects of sorafenib on HepG2 cell apoptosis were significantly enhanced by combining with herbacetin, which was associated with increased sorafenib exposure. In summary, herbacetin is a potent inhibitor of a wide spectrum of CYP450s, which may enhance the exposure of drugs in vivo.

Cytochrome P450 3A5 polymorphism affects the metabolism of sorafenib and its toxicity for hepatocellular carcinoma cells in vitro

OBJECTIVE

Cytochrome P450 3A5 (CYP3A5) is a highly polymorphic gene and the encoded protein variants differ in catalytic activity, leading to inter-individual variation in metabolic ability. The aim of the current study was to investigate the effects of seven allelic variants on the ability of CYP3A5 to metabolize sorafenib in vitro and further explore the impacts of CYP3A5 polymorphism on the proliferation and apoptosis of hepatocellular carcinoma cell line (HepG2) induced by sorafenib.

METHODS

Wild-type and variant CYP3A5 enzymes were expressed in Spodoptera frugiperda insect cells using a baculovirus dual-expression system, and protein expression was checked by western blot. The enzymes were incubated with sorafenib at 37°C for 30 min, and formation of the major metabolite sorafenib N-oxide was assayed using ultra-performance liquid chromatography and tandem mass spectrometry. Intrinsic clearance values (V_max/K_m) were calculated for each enzyme. Additionally, recombinant HepG2 cells transfecting with CYP3A5 variants were used to investigate the effects of sorafenib on the proliferation of HepG2 cells.

RESULTS

Intrinsic clearance of the six variants CYP3A5*2, CYP3A5*3A, CYP3A5*3C, CYP3A5*4, CYP3A5*5, and CYP3A5*7 was 26.41-71.04% of the wild-type (CYP3A5*1) value. In contrast, the clearance value of the variant CYP3A5*6 was significantly higher (174.74%). Additionally, the decreased ATP levels and cell viability and the increased cell apoptosis in HepG2 cells transfected with CYP3A5*2, CYP3A5*3A, CYP3A5*3C, CYP3A5*4, CYP3A5*5, and CYP3A5*7 were observed, whereas, the increased ATP levels and cell viability and the reduced cell apoptosis in HepG2 cells transfected with CYP3A5*6 were also investigated when compared to CYP3A5*1.

CONCLUSION

Our results suggest that CYP3A5 polymorphism influences sorafenib metabolism and pharmacotherapeutic effect in hepatic carcinomas. These data may help explain differential response to drug therapy for hepatocellular carcinoma, and they support the need for individualized treatment.

Cytochrome P450 3A5 polymorphism affects the metabolism of sorafenib and its toxicity for hepatocellular carcinoma cells in vitro

OBJECTIVE

Cytochrome P450 3A5 (CYP3A5) is a highly polymorphic gene and the encoded protein variants differ in catalytic activity, leading to inter-individual variation in metabolic ability. The aim of the current study was to investigate the effects of seven allelic variants on the ability of CYP3A5 to metabolize sorafenib in vitro and further explore the impacts of CYP3A5 polymorphism on the proliferation and apoptosis of hepatocellular carcinoma cell line (HepG2) induced by sorafenib.

METHODS

Wild-type and variant CYP3A5 enzymes were expressed in Spodoptera frugiperda insect cells using a baculovirus dual-expression system, and protein expression was checked by western blot. The enzymes were incubated with sorafenib at 37°C for 30 min, and formation of the major metabolite sorafenib N-oxide was assayed using ultra-performance liquid chromatography and tandem mass spectrometry. Intrinsic clearance values (V_max/K_m) were calculated for each enzyme. Additionally, recombinant HepG2 cells transfecting with CYP3A5 variants were used to investigate the effects of sorafenib on the proliferation of HepG2 cells.

RESULTS

Intrinsic clearance of the six variants CYP3A5*2, CYP3A5*3A, CYP3A5*3C, CYP3A5*4, CYP3A5*5, and CYP3A5*7 was 26.41-71.04% of the wild-type (CYP3A5*1) value. In contrast, the clearance value of the variant CYP3A5*6 was significantly higher (174.74%). Additionally, the decreased ATP levels and cell viability and the increased cell apoptosis in HepG2 cells transfected with CYP3A5*2, CYP3A5*3A, CYP3A5*3C, CYP3A5*4, CYP3A5*5, and CYP3A5*7 were observed, whereas, the increased ATP levels and cell viability and the reduced cell apoptosis in HepG2 cells transfected with CYP3A5*6 were also investigated when compared to CYP3A5*1.

CONCLUSION

Our results suggest that CYP3A5 polymorphism influences sorafenib metabolism and pharmacotherapeutic effect in hepatic carcinomas. These data may help explain differential response to drug therapy for hepatocellular carcinoma, and they support the need for individualized treatment.

Clinical Pharmacokinetics and Pharmacodynamics of Transarterial Chemoembolization and Targeted Therapies in Hepatocellular Carcinoma

The management of hepatocellular carcinoma (HCC) is based on a multidisciplinary decision tree. Treatment includes loco-regional therapy, mainly transarterial chemoembolization, for intermediate-stage HCC and systemic therapy with oral tyrosine kinase inhibitors (TKIs) for advanced HCC. Transarterial chemoembolization involves hepatic intra-arterial infusion with either conventional procedure or drug-eluting-beads. The aim of the loco-regional procedure is to deliver treatment as close as possible to the tumor both to embolize the tumor area and to enhance efficacy and minimize systemic toxicity of the anticancer drug. Pharmacokinetic studies applied to transarterial chemoembolization are rare and pharmacodynamic studies even rarer. However, all available studies lead to the same conclusions: use of the transarterial route lowers systemic exposure to the cytotoxic drug and leads to much higher tumor drug concentrations than does a similar dose via the intravenous route. However, reproducibility of the procedure remains a major problem, and no consensus exists regarding the choice of anticancer drug and its dosage. Systemic therapy with TKIs is based on sorafenib and lenvatinib as first-line treatment and regorafenib and cabozantinib as second-line treatment. Clinical use of TKIs is challenging because of their complex pharmacokinetics, with high liver metabolism yielding both active metabolites and their common toxicities. Changes in liver function over time with the progression of HCC adds further complexity to the use of TKIs. The challenges posed by TKIs and the HCC disease process means monitoring of TKIs is required to improve clinical management. To date, only partial data supporting sorafenib monitoring is available. Results from further pharmacokinetic/pharmacodynamic studies of these four TKIs are eagerly awaited and are expected to permit such monitoring and the development of consensus guidelines.

The systemic inflammatory response as a source of biomarkers and therapeutic targets in hepatocellular carcinoma

The pathogenesis of hepatocellular carcinoma (HCC) strongly relates to inflammation, with chronic up-regulation of pro-inflammatory mediators standing as a potential unifying mechanism that underscores the origin and progression of HCC independent of aetiology. Activation of the diverse pro-inflammatory mediators either within the tumour or its microenvironment is part of an active cross-talk between the progressive HCC and the host, which is known to influence clinical outcomes including recurrence after radical treatments and long-term survival. A number of clinical biomarkers to measure the severity of cancer-related inflammation are now available, most of which emerge from routine blood parameters including neutrophil, lymphocyte, platelet counts, as well as albuminaemia and C-reactive protein levels. In this review, we summarise the body of evidence supporting the biologic qualification of inflammation-based scores in HCC and review their potential in facilitating the prognostic assessment and treatment allocation in the individual patient. We also discuss the evidence to suggest modulation of tumour-promoting inflammation may act as a source of novel therapeutic strategies in liver cancer.

Inhibition of Hepatic CYP2D6 by the Active N-Oxide Metabolite of Sorafenib

The multikinase inhibitor sorafenib (SOR) is used to treat patients with hepatocellular and renal carcinomas. SOR undergoes CYP-mediated biotransformation to a pharmacologically active N-oxide metabolite (SNO) that has been shown to accumulate to varying extents in individuals. Kinase inhibitors like SOR are frequently coadministered with a range of other drugs to improve the efficacy of anticancer drug therapy and to treat comorbidities. Recent evidence has suggested that SNO is more effective than SOR as an inhibitor of CYP3A4-mediated midazolam 1'-hydroxylation. CYP2D6 is also reportedly inhibited by SOR. The present study assessed the possibility that SNO might contribute to CYP2D6 inhibition. The inhibition kinetics of CYP2D6-mediated dextromethorphan O-demethylation were analyzed in human hepatic microsomes, with SNO found to be ~ 19-fold more active than SOR (K_is 1.8 ± 0.3 μM and 34 ± 11 μM, respectively). Molecular docking studies of SOR and SNO were undertaken using multiple crystal structures of CYP2D6. Both molecules mediated interactions with key amino acid residues in putative substrate recognition sites of CYP2D6. However, a larger number of H-bonding interactions was noted between the N-oxide moiety of SNO and active site residues that account for its greater inhibition potency. These findings suggest that SNO has the potential to contribute to pharmacokinetic interactions involving SOR, perhaps in those individuals in whom SNO accumulates.

The tissue distribution and excretion study of mosapride and its active des-p-fluorobenzyl and 4'-N-oxide metabolites in rats by ultra-high performance liquid chromatography-tandem mass spectrometry method

1. Mosapride is a potent gastroprokinetic agent, and des-p-fluorobenzyl mosapride (M1) and mosapride-N-oxide (M2) are its two major active metabolites.2. The validated ultra-high performance liquid chromatography-tandem mass spectrometry method was successfully applied to the distribution and excretion of mosapride and its two active metabolites.3. Mosapride and its metabolites were distributed widely and rapidly in various tissues. The highest concentration of mosapride and M2 in both male and female rats was found in the duodenum, followed by cecum.4. The excretion study showed that a total of 71.8% (37.6, 22.4 and 11.8% for urine, feces and bile, respectively) and 66.3% (35.7, 22.8 and 7.8% for urine, feces and bile) of administered dose was recovered from male and female excreta. M1 was excreted in the largest dose percentage, followed by mosapride and M2, and the total cumulative excretion amounts were about 36.9, 28.1 and 11.6% in male rat, while 24.3, 25.9 and 16.2% in female rat. The results demonstrated for the first time that M2 is one of the important excretion forms of mosapride, which is much higher than that of mosapride in urine.5. This work could provide valuable information for further pharmacological and clinical studies of mosapride.

Enzyme-Activated Generation of Reactive Oxygen Species from Heterocyclic N-Oxides under Aerobic and Anaerobic Conditions and Its Relevance to Hypoxia-Selective Prodrugs

Enzymatic one-electron reduction of heterocyclic N-oxides can lead to the intracellular generation of reactive oxygen species via several different chemical pathways. These reactions may be relevant to hypoxia-selective anticancer drugs, antimicrobial agents, and unwanted toxicity of heterocylic nitrogen compounds.

The effects of triptolide on the pharmacokinetics of sorafenib in rats and its potential mechanism

CONTEXT

Combining sorafenib with triptolide could inhibit tumour growth with greater efficacy than single-agent treatment. However, their herb-drug interaction remains unknown.

OBJECTIVE

This study investigates the herb-drug interaction between triptolide and sorafenib.

MATERIALS AND METHODS

The effects of triptolide (10 mg/kg) on the pharmacokinetics of different doses of sorafenib (20, 50 and 100 mg/kg) in rats, and blood samples were collected within 48 h and evaluated using LC-MS/MS. The effects of triptolide on the absorption and metabolism of sorafenib were also investigated using Caco-2 cell monolayer model and rat liver microsome incubation systems.

RESULTS

The results showed that the C_max (low dose: 72.38 ± 8.76 versus 49.15 ± 5.46 ng/mL; medium dose: 178.65 ± 21.05 versus 109.31 ± 14.17 ng/mL; high dose: 332.81 ± 29.38 versus 230.86 ± 9.68 ng/mL) of sorafenib at different doses increased significantly with the pretreatment of triptolide, and while the oral clearance rate of sorafenib decreased. The t_1/2 of sorafenib increased significant (p < 0.05) from 9.02 ± 1.16 to 12.17 ± 2.95 h at low dose with the pretreatment of triptolide. Triptolide has little effect on the absorption of sorafenib in Caco-2 cell transwell model. However, triptolide could significantly decrease the intrinsic clearance rate of sorafenib from 51.7 ± 6.37 to 32.4 ± 4.43 μL/min/mg protein in rat liver microsomes.

DISCUSSION AND CONCLUSIONS

These results indicated that triptolide could change the pharmacokinetic profiles of sorafenib in rats; these effects might be exerted via decreasing the intrinsic clearance rate of sorafenib in rat liver.

Herb-Drug Interaction between the Traditional Hepatoprotective Formulation and Sorafenib on Hepatotoxicity, Histopathology and Pharmacokinetics in Rats

Sorafenib has been used as a standard therapy for advanced hepatocellular carcinoma (HCC). In Asia, patients with HCC are potentially treated with the combination of sorafenib and Chinese herbal medicines to improve the efficiency and reduce the side effects of sorafenib. However, limited information about the herb-drug interactions is available. We hypothesize that the Chinese herbal medicine may exert hepatoprotective effects on the sorafenib-treated group. The aim of this study is to investigate the pharmacokinetic mechanism of drug-drug interactions of sorafenib including interacting with hepatoprotective formulation, Long-Dan-Xie-Gan-Tang formulation (LDXGT) and with two cytochrome P450 3A4 (CYP3A4) inhibitors, grapefruit juice and ketoconazole. Liver enzyme levels and histopathology of liver slices were used to evaluate sorafenib-induced hepatotoxicity and the potential hepatoprotective effects of the LDXGT formulation on subjects treated with the combination of sorafenib and the herbal medicine. In this study, a validated HPLC-photodiode array analytical system was developed for the pharmacokinetic study of sorafenib in rats. As the result of the pharmacokinetic data, pretreatment with the LDXGT formulation did not significantly interact with sorafenib compared with sorafenib oral administration alone. Furthermore, grapefruit juice and ketoconazole did not significantly affect sorafenib metabolism. Furthermore, pretreatment with variable, single or repeat doses of the LDXGT formulation did not suppress or exacerbate the sorafenib-induced hepatotoxicity and histopathological alterations. According to these results, the LDXGT formulation is safe, but has no beneficial effects on sorafenib-induced hepatotoxicity. A detailed clinical trial should be performed to further evaluate the efficacy or adverse effects of the LDXGT formulation in combination with sorafenib in humans.