Role of Cytochrome P450 Phenotyping in Cancer Treatment

CYP4F12 is a potential biomarker and inhibits cell migration of head and neck squamous cell carcinoma via EMT pathway

Head and neck squamous cell carcinoma (HNSC) is the most common malignant tumor of head and neck. Due to the insidious nature of HNSC and the lack of effective early diagnostic indicators, the development of novel biomarkers to improve patient prognosis is particularly urgent. In this study, we explored and validated the correlation between cytochrome P450 family 4 subfamily F member 12 (CYP4F12) expression levels and HNSC progression using data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) datasets and collected patient samples. We analyzed the association of CYP4F12 expression with clinicopathological features, immune correlation and prognosis. Finally, we analyzed the correlation between CYP4F12 and pathways, and verified by experiments. The results showed that CYP4F12 was low expressed in tumor tissues, participated in a variety of phenotypic changes of HNSC and affected immune cell infiltration. Pathway analysis indicated that CYP4F12 may play a key role in tumor cell migration and apoptosis. Experimental results showed that over-expression of CYP4F12 inhibited cell migration and enhanced the adhesion between cells and matrix by inhibiting epithelial-mesenchymal transition (EMT) pathway in HNSC cells. In conclusion, our study provided insights into the role of CYP4F12 in HNSC and revealed that CYP4F12 may be a potential therapeutic target for HNSC.

Transcriptional profiling and network pharmacology analysis identify the potential biomarkers from Chinese herbal formula Huosu Yangwei Formula treated gastric cancer in vivo

Huosu Yangwei (HSYW) Formula is a traditioanl Chinese herbal medicine that has been extensively used to treat chronic atrophic gastritis, precancerous lesions of gastric cancer and advanced gastric cancer. However, the effective compounds of HSYW and its related anti-tumor mechanisms are not completely understood. In the current study, 160 ingredients of HSYW were identified and 64 effective compounds were screened by the ADMET evaluation. Furthermore, 64 effective compounds and 2579 potential targets were mapped based on public databases. Animal experiments demonstrated that HSYW significantly inhibited tumor growth in vivo. Transcriptional profiles revealed that 81 mRNAs were differentially expressed in HSYW-treated N87-bearing Balb/c mice. Network pharmacology and PPI network showed that 12 core genes acted as potential markers to evaluate the curative effects of HSYW. Bioinformatics and qRT-PCR results suggested that HSYW might regulate the mRNA expression of DNAJB4, CALD, AKR1C1, CST1, CASP1, PREX1, SOCS3 and PRDM1 against tumor growth in N87-bearing Balb/c mice.

Study Protocol for a Pilot, Open-Label, Prospective, and Observational Study to Evaluate the Pharmacokinetics of Drugs Administered to Patients during Extracorporeal Circulation; Potential of In Vivo Cytochrome P450 Phenotyping to Optimise Pharmacotherapy

Pharmacokinetic alterations of medications administered during surgeries involving cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) have been reported. The impact of CPB on the cytochrome P450 (CYP) enzymes’ activity is the key factor. The metabolic rates of caffeine, dextromethorphan, midazolam, omeprazole, and Losartan to the CYP-specific metabolites are validated measures of in vivo CYP 1A2, 2D6, 3A4, 2C19, and 2C9 activities, respectively. The study aim is to assess the activities of major CYPs in patients on extracorporeal circulation (EC). This is a pilot, prospective, open-label, observational study in patients undergoing surgery using EC and patients undergoing laparoscopic cholecystectomy as a control group. CYP activities will be measured on the day, and 1–2 days pre-surgery/3–4 days post-surgery (cardiac surgery and Laparoscopic cholecystectomy) and 1–2 days after starting ECMO, 1–2 weeks after starting ECMO, and 1–2 days after discontinuation from ECMO. Aforementioned CYP substrates will be administered to the patient and blood samples will be collected at 0, 1, 2, 4, and 6 h post-dose. Major CYP enzymes’ activities will be compared in each participant on the day, and before/after surgery. The CYP activities will be compared in three study groups to investigate the impact of CYPs on EC.

Influence of SLCO1B1 in gastric cancer patients treated with EOF chemotherapy

Cytochrome-P450 enzymes, ATP-binding cassette transporters, and solute carriers mediate drug metabolism as metabolic enzymes and membrane transporters, respectively. The present study investigated whether single nucleotide polymorphisms (SNPs) in genes encoding these proteins were predictive or prognostic factors in patients with metastatic gastric cancer (MGC) undergoing chemotherapy. A retrospective study of 108 MGC patients who received epirubicin, oxaliplatin, and 5-fluorouracil (EOF) as first-line treatment was performed. A total of 13 SNPs were genotyped, including SLCO1B1 (rs4149056), SLC2A9 (rs16890979, rs6449213, rs734553), ABCG2 (rs2231142), CYP2C9 (rs1057910, rs1799853), CYP2C19 (rs72552267, rs28399504, rs56337013, rs41291556) and CYP1A2 (rs12720461, rs56107638). The associations between these genotypes and disease-control rate (DCR), progression-free survival (PFS) and overall survival (OS) were analyzed. Patients with SLCO1B1 rs4149056 TT genotype had a significantly shorter OS compared with those with a C allele (CC + CT; 312 vs. 565 days, P=0.039). Multivariate analysis revealed that the rs4149056 TT homozygous genotype was an independent prognostic factor for shorter OS (hazard ratio: 2.565, 95% confidence interval: 1.215–5.415, P=0.014). However, no significant associations between SLCO1B1 rs4149056 and PFS were observed, between the other 12 SNPs and PFS or OS, or between any of the 13 SNPs and DCR. In conclusion, SLCO1B1 rs4149056 TT may be an independent predictor of survival in patients with MCG treated with EOF chemotherapy.

Role of xenobiotic metabolism enzyme gene polymorphism in the formation of chemotherapy resistance in patients with chronic lymphoproliferative diseases

Enzymes of the cytochrome P450 and GSTP1 families play a pivotal role in the metabolism of a wide variety of antitumor drugs and polymorphisms of genes encoding for metabolizing enzymes can affect drug efficacy and toxicity. We studied the associations between functionally significant gene polymorphisms CYP2C8, CYP2C9, CYP2C19, CYP3A5, and GSTP1 and clinical response to chemotherapy in patients with chronic lymphoproliferative diseases. Significant correlations with chemotherapy resistance were observed for CYP2C8 3 (OR=7.05; CI 95%=1.76-29.55) and CYP2C9 2 polymorphisms (OR=4.1; CI 95%=1.03-16.81). No significant association between chemotherapy resistance and other examined polymorphisms were found.

Association of cytochrome P450 genetic polymorphisms with neoadjuvant chemotherapy efficacy in breast cancer patients

Background

The enzymes of the cytochrome P450 family (CYPs) play an important role in the metabolism of a great variety of anticancer agents; therefore, polymorphisms in genes encoding for metabolizing enzymes and drugs transporters can affect drug efficacy and toxicity.

Methods

The genetic polymorphisms of cytochrome P450 were studied in 395 patients with breast cancer by RLFP analysis.

Results

Here, we studied the association of functionally significant variant alleles of CYP3A4, CYP3A5, CYP2B6, CYP2C8, CYP2C9 and CYP2C19 with the clinical response to neoadjuvant chemotherapy in breast cancer patients. A significant correlation was observed between the CYP2C9*2 polymorphism and chemotherapy resistance (OR = 4.64; CI 95% = 1.01 – 20.91), as well as between CYP2C9*2 heterozygotes and chemotherapy resistance in women with nodal forms of breast cancer and a cancer hereditary load (OR = 15.50; CI 95% = 1.08 – 826.12) when the potential combined effects were examined. No significant association between chemotherapy resistance and the other examined genotypes and the potential combined clinical and tumour-related parameters were discovered.

Conclusion

In conclusion, CYP2C9*2 was associated with neoadjuvant chemotherapy resistance (OR = 4.64; CI 95% = 1.01 – 20.91) in the population of interest.

Phase I Trial with BMS-275183, a Novel Oral Taxane with Promising Antitumor Activity

PURPOSE

BMS-275183 is an orally administered C-4 methyl carbonate analogue of paclitaxel. We did a dose-escalating phase I study to investigate its safety, tolerability, pharmacokinetics, and possible antitumor activity.

EXPERIMENTAL DESIGN

A cycle consisted of four weekly doses of BMS-275183. The starting dose was 5 mg, which was increased by 100% increments (i.e., 5, 10, 20 mg/m2, etc.) in each new cohort consisting of one patient. Cohorts were expanded when toxicity was encountered, and 20 patients were treated at the maximum tolerated dose (MTD). Plasma pharmacokinetics were done on days 1 and 15.

RESULTS

A total of 48 patients were enrolled in this trial. Dose-limiting toxicities consisted of neuropathy, fatigue, diarrhea, and neutropenia. First cycle severe neuropathy was reported in four patients treated at 320 (n = 1), 240 (n = 2), and 160 mg/m2 (n = 1), whereas eight patients treated at dose levels ranging from 160 to 320 mg/m2 experienced grade 2 neuropathy in cycle one. The MTD was 200 mg/m2, as 3 of 20 patients experienced grade 3 or 4 toxicity in cycle one [fatigue (n = 2), and neutropenia/diarrhea (n = 1)]. BMS-275183 was rapidly absorbed with a mean plasma half-life of 22 hours. We observed a significant correlation between drug-exposure and toxicity. Tumor responses were observed in 9 of 38 evaluable patients with non-small cell lung cancer, prostate carcinoma, and other tumor types.

CONCLUSIONS

BMS-275183 is generally well tolerated on a weekly schedule. The main toxicity is peripheral neuropathy, and the MTD is 200 mg/m2. Promising activity was observed in several tumor types, and a phase II trial in non-small cell lung cancer has been initiated.

Role of pharmacogenetics in irinotecan therapy

In the treatment of advanced colorectal cancer, irinotecan has become one of the most important drugs, despite its sometimes unpredictable adverse effects. To understand why some patients experience severe adverse effects (diarrhea and neutropenia), while others do not, the metabolic pathways of this drug have to be unraveled in detail. Individual variation in expression of several phase I and phase II metabolizing enzymes and ABC-transporters involved in irinotecan metabolism and excretion, at least partly explains the observed pharmacokinetic interpatient variability. Although the difference in expression-level of these proteins to a certain amount is explained by physiologic and environmental factors, the presence of specific genetic determinants also does influence their expression and function. In this review, the role of genetic polymorphisms in the main enzyme-systems (carboxylesterase, cytochrome P450 3A, and uridine diphosphate-glucuronosyltransferase) and ABC-transporters (ABCB1, ABCC2, and ABCG2) involved in irinotecan metabolism, are discussed. Since at this moment the field of pharmacogenetics and pharmacogenomics is rapidly expanding and simultaneously more rapid and cost-effective screening methods are emerging, a wealth of future data is expected to enrich our knowledge of the genetic basis of irinotecan metabolism. Eventually, this may help to truly individualize the dosing of this (and other) anti-cancer agent(s), using a personal genetic profile of the most relevant enzymes for every patient.

Genotyping and phenotyping cytochrome P450: Perspectives for cancer treatment

As most anticancer agents display a narrow therapeutic window, patients may be susceptible to (extreme) toxicities or a lowered therapeutic outcome if not dosed adequately. Therefore, it is important to study factors which affect the pharmacokinetics and pharmacodynamics of these drugs. Among these, the contribution of genetic variation in drug metabolizing enzymes on the metabolism of anticancer agents has gathered interest, as it may potentially explain a substantial amount of interpatient variability in pharmacokinetics and drug response. Cytochrome P450, an oxidative enzyme-system involved in the breakdown of many drugs, is currently studied for correlations between genetic polymorphisms and anticancer drug metabolism. Also, alternative ways to predict the expression of cytochrome P450 have been developed (phenotyping measures) which may have additional value in creating a lowered interpatient variability, to minimize side-effects and maximize therapeutic efficacy.

Use of directed evolution of mammalian cytochromes P450 for investigating the molecular basis of enzyme function and generating novel biocatalysts

Directed evolution has been successfully applied to the design of industrial biocatalysts for enhanced catalytic efficiency and stability, and for examining the molecular basis of enzyme function. Xenobiotic-metabolizing mammalian cytochromes P450 with their catalytic versatility and broad substrate specificity offer the possibility of widespread applications in industrial synthesis, medicine, and bioremediation. However, the requirement for NADPH-cytochrome P450 reductase, often cytochrome b5, and an expensive cofactor, NADPH, complicates the design of mammalian P450 enzymes as biocatalysts. Recently, Guengerich and colleagues have successfully performed directed evolution of P450s 1A2 and 2A6 initially by using colony-based colorimetric and genotoxicity screening assays, respectively, followed by in vitro fluorescence-based activity screening assays. More recently, our laboratory has developed a fluorescence-based in vitro activity screening assay system for enhanced catalytic activity of P450s 2B1 and 3A4. The studies indicate an important role of amino acid residues outside of the active site, which would be difficult to target by other methods. The approach can now be expanded to design these as well as new P450s using more targeted substrates of environmental, industrial, and medical importance.