The effect of CYP2D6 *10 polymorphism on adjuvant tamoxifen in Asian breast cancer patients: a meta-analysis

The landscape of very important pharmacogenes variants and potential clinical relevance in the Chinese Jingpo population: a comparative study with worldwide populations

BACKGROUND

Pharmacogenomics is a facet of personalized medicine that explores how genetic variants affect drug metabolism and adverse drug reactions. Therefore, this study aims to detect distinct pharmacogenomic variations among the Jingpo population and explore their clinical correlation with drug metabolism and toxicity.

METHODS

Agena MassARRAY Assay was used to genotype 57 VIP variants in 28 genes from 159 unrelated Jingpo participants. Subsequently, the chi-squared test and Bonferroni's statistical tests were utilized to conduct a comparative analysis of genotypes and allele frequencies between the Jingpo population and the other 26 populations from the 1000 Genome Project.

RESULTS

We discovered that the KHV (Kinh in Ho ChiMinh City, Vietnam), CHS (Southern Han Chi-nese, China) and JPT (Japanese in Tokyo, Japan) exhibited the smallest differences from the Jingpo with only 4 variants, while ESN (Esan in Nigeria) exhibited the largest differences with 30 variants. Besides, a total of six considerably different loci (rs4291 in ACE, rs20417 in PTGS2, rs1801280 and rs1799929 in NAT2, rs2115819 in ALOX5, rs1065852 in CYP2D6, p < 3.37 × 10-5) were identified in this study. According to PharmGKB, rs20417 (PTGS2), rs4291 (ACE), rs2115819 (ALOX5) and rs1065852 (CYP2D6) were found to be associated with the metabolism efficiency of non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, montelukast and tamoxifen, respectively. Meanwhile, rs1801280 and rs1799929 (NAT2) were found to be related to drug poisoning with slow acetylation.

CONCLUSION

Our study unveils distinct pharmacogenomic variants in the Jingpo population and discovers their association with the metabolic efficiency of NSAIDs, montelukast, and tamoxifen.

Genetic Polymorphisms of Cytochromes P450 in Finno-Permic Populations of Russia

Cytochrome P450 is an enzyme involved in the metabolism of phase 1 xenobiotics, toxins, endogenous hormones, and drugs, including those used in COVID-19 treatment. Cytochrome p450 genes are linked to the pathogenesis of some multifactorial traits and diseases, such as cancer, particularly prostate cancer, colorectal cancer, breast cancer, and cervical cancer. Genotyping was performed on 540 supposedly healthy individuals of 5 Finno-Permic populations from the territories of the European part of the Russian Federation. There was a statistically significant difference between Veps and most of the studied populations in the rs4986774 locus of the CYP2D6 gene; data on the rs3892097 locus of the CYP2D6 gene shows that Izhemsky Komis are different from the Mordovian and Udmurt populations.

Marine-Derived Stichloroside C2 Inhibits Epithelial–Mesenchymal Transition and Induces Apoptosis through the Mitogen-Activated Protein Kinase Signalling Pathway in Triple-Negative Breast Cancer Cells

Background

Triterpenoid saponins from sea cucumbers exhibit significant antitumour, antifungal, and antibacterial activities. However, the associated molecular mechanisms have yet to be elucidated. In this study, we screened and explored the antitumour activity and underlying mechanisms of triterpenoid saponins isolated from Thelenota ananas.

Methods

We isolated and purified sea cucumber saponins, determined their chemical structures, and confirmed their function in vitro. We also screened and explored the antitumour activity and underlying mechanisms of triterpenoid saponins isolated from Thelenota ananas.

Results

Four saponins were discovered from sea cucumber Thelenota ananas collected from the South China Sea. We found that stichloroside C2 (STC2) inhibited the proliferation and clonogenesis of the human triple-negative breast cancer (TNBC) cell line MDA-MB-231 and mouse TNBC cell line 4 T1 in a dose-dependent manner and induced apoptosis and cycle arrest in these two TNBC cell lines. STC2 induced DNA damage in two TNBC cell lines and significantly increased the protein expression level of the DNA double-strand break marker γ-H2AX. STC2 downregulated the protein expression levels of phosphorylated cyclin-dependent kinase 1 (CDK1), cyclin B1, CDK2, and cyclin A2 in MDA-MB-231 and 4 T1 cells. STC2 upregulated Bax and cleaved PARP protein expression in two types of breast cancer cells. In addition, STC2 promoted E-cadherin expression; inhibited vimentin expression; upregulated the phosphorylation levels of the mitogen-activated protein kinase (MAPK) signalling pathway-related proteins p38, JNK, and ERK1/2; and downregulated Akt phosphorylation.

Conclusions

STC2 exerts anti-TNBC activity, inhibits epithelial–mesenchymal transition (EMT), and induces apoptosis by regulating the cell cycle, EMT-related proteins, and MAPK signalling pathway.

Improving the transparency of meta-analyses with interactive web applications

Increased transparency in study design and analysis is one proposed solution to the perceived reproducibility crisis facing science. Systematic review and meta-analysis-through which individual studies on a specific association are ascertained, assessed for quality and quantitatively combined-is a critical process for building consensus in medical research. However, the conventional publication model creates static evidence summaries that force the quality assessment criteria and analytical choices of a small number of authors onto all stakeholders, some of whom will have different views on the quality assessment and key features of the analysis. This leads to discordant inferences from meta-analysis results and delayed arrival at consensus. We propose a shift to interactive meta-analysis, through which stakeholders can take control of the evidence synthesis using their own quality criteria and preferred analytic approach-including the option to incorporate prior information on the association in question-to reveal how their summary estimate differs from that reported by the original analysts. We demonstrate this concept using a web-based meta-analysis of the association between genetic variation in a key tamoxifen-metabolising enzyme and breast cancer recurrence in tamoxifen-treated women. We argue that interactive meta-analyses would speed consensus-building to the degree that they reveal invariance of inferences to different study selection and analysis criteria. On the other hand, when inferences are found to differ substantially as a function of these choices, the disparities highlight where future research resources should be invested to resolve lingering sources of disagreement.

An Overview of the Treatment Efficacy and Side Effect Profile of Pharmacological Therapies in Asian Patients with Breast Cancer

Breast cancer (BC) among Asians accounts for ~ 40% of the global BC burden. Differences in BC risk, presentation, tumor biology, and response to treatment exist between Asian and non-Asian patients; however, Asian patients are often under-represented in clinical trials. This narrative review summarizes the efficacy and safety of pharmacological therapies for BC in Asian populations, with a focus on outcomes in Asian versus non-Asian patients treated with chemotherapy, hormone therapy, anti-human epidermal growth factor receptor-2 targeted therapies, cyclin-dependent kinase 4/6 (CDK4/6) inhibitors, mammalian target of rapamycin inhibitors, bone-targeted therapies, poly-ADP ribose polymerase, phosphoinositide 3-kinase, and checkpoint inhibitors. While most therapies have demonstrated comparable efficacy and safety in Asian and non-Asian patients with BC, differences that are largely attributed to pharmacogenetic variations between populations exist. Pharmacogenetic differences may contribute to a reduced clinical benefit of tamoxifen, whereas improved clinical outcomes have been reported with tyrosine kinase inhibitors and CDK4/6 inhibitors in Asian versus non-Asian patients with BC. In particular, Asian patients have an increased incidence of hematological toxicities, including neutropenia, although adverse events can be effectively managed using dose adjustments. Recent trials with CDK4/6 inhibitors have increased efforts to include Asians within study subsets. Future clinical trials enrolling higher numbers of Asian patients, and an increased understanding of differences in patient and tumor genetics between Asians and non-Asians, have the potential to incrementally improve the management of BC in Asian patients.

Computational Treatment Simulations to Assess the Need for Personalized Tamoxifen Dosing in Breast Cancer Patients of Different Biogeographical Groups

Simple Summary

Tamoxifen is a drug often used to treat the most common type of breast cancer. Its metabolite endoxifen is formed by the liver enzyme CYP2D6, whose activity is variable and depends on a patient’s genetic profile. The frequency of CYP2D6 variants with different functional enzymatic activity varies largely between populations. To ensure sufficient efficacy of tamoxifen, a certain target concentration of endoxifen is needed, and 20% of White breast cancer patients have been shown not to reach this target concentration. However, little is known about the risk of not attaining the endoxifen target amongst other ethnic populations. This study investigated the risk for suboptimal endoxifen concentration in nine different biogeographical populations based on their distinct CYP2D6 genetic profile. The variability between the populations was high (up to three-fold), and East Asian breast cancer patients were identified as the population with the highest need for personalized tamoxifen dosing.

Abstract

Tamoxifen is used worldwide to treat estrogen receptor-positive breast cancer. It is extensively metabolized, and minimum steady-state concentrations of its metabolite endoxifen (C_{SS,min ENDX}) >5.97 ng/mL have been associated with favorable outcome. Endoxifen formation is mediated by the enzyme CYP2D6, and impaired CYP2D6 function has been associated with lower C_SS,min ENDX. In the Women’s Healthy Eating and Living (WHEL) study proposing the target concentration, 20% of patients showed subtarget C_{SS,min ENDX} at tamoxifen standard dosing. CYP2D6 allele frequencies vary largely between populations, and as 87% of the patients in the WHEL study were White, little is known about the risk for subtarget C_{SS,min ENDX} in other populations. Applying pharmacokinetic simulations, this study investigated the risk for subtarget C_{SS,min ENDX} at tamoxifen standard dosing and the need for dose individualization in nine different biogeographical groups with distinct CYP2D6 allele frequencies. The high variability in CYP2D6 allele frequencies amongst the biogeographical groups resulted in an up to three-fold difference in the percentages of patients with subtarget C_{SS,min ENDX}. Based on their CYP2D6 allele frequencies, East Asian breast cancer patients were identified as the population for which personalized, model-informed precision dosing would be most beneficial (28% of patients with subtarget C_{SS,min ENDX}).

Could Cytochrome P450 2D6, 3A4 and 3A5 Polymorphisms Explain the Variability in Clinical Response to Clomiphene Citrate of Anovulatory PCOS Women?

INTRODUCTION

Cytochrome P450 2D6, 3A4 and 3A5 are involved in the metabolism of many drugs. These enzymes have a genetic polymorphism responsible for different metabolic phenotypes. They play a role in the metabolism of clomiphene citrate (CC), which is used to induce ovulation. Response to CC treatment is variable, and no predictive factors have thus far been identified.

OBJECTIVE

To study a possible link between the cytochrome P450 2D6, 3A4 and 3A5 polymorphisms and clinical response to CC.

STUDY DESIGN

Seventy-seven women with anovulatory Polycystic Ovarian Syndrome (PCOS) treated with CC were included which determined their cytochrome P450 2D6, 3A4 and 3A5 genotypes and used the results to predict ovarian response to this drug. Predicted responses based on the cytochrome genotypes were compared with the observed clinical responses using the calculation of a weighted Kappa coefficient.

MAIN OUTCOME MEASURES

Number of dominant follicles assessed by ultrasound at the end of the follicular phase and confirmation of ovulation by blood progesterone assay in the luteal phase.

RESULTS

Concordance between the predicted and observed responses for the combination of the three cytochromes was 36.71%, with a negative Kappa coefficient (K = -0.0240), which corresponds to a major disagreement. Similarly, for predictions based on the cytochrome P450 2D6 genotype alone, only 39.24% of predictions were verified (coefficient K = -0.0609).

CONCLUSION

The genetic polymorphism of cytochromes P450 2D6, 3A4 and 3A5 does not appear to influence clinical response to CC used to induce ovulation in anovulatory PCOS women.

Cost-effectiveness Analysis of CYP2D6*10 Pharmacogenetic Testing to Guide the Adjuvant Endocrine Therapy for Postmenopausal Women with Estrogen Receptor Positive Early Breast Cancer in China

BACKGROUND

A CYP2D6 gene polymorphism is related to the effect of tamoxifen treatment in patient with estrogen-receptor positive (ER) positive breast cancer and CYP2D6*10 T/T can lead to a poor prognosis in Asian patients. Although one-off pharmacogenetic testing may optimize adjuvant endocrine therapy, testing prior to tamoxifen initiation incurs additional costs.

AIM

We conducted a study to assess the cost-effectiveness of CYP2D6*10 pharmacogenetic testing to guide the adjuvant endocrine therapy compared with tamoxifen without CYP2D6*10 testing in China.

METHODS

A semi-Markov model was developed to evaluate costs and health outcomes represented as quality adjusted life year (QALY) gained. Input data were obtained from the public literature. The results were expressed as incremental cost per QALY gained. A one-way deterministic sensitivity analysis explored the impact of uncertainty in the model parameters on results, and probabilistic uncertainty was assessed through a Monte Carlo probabilistic sensitivity analysis.

RESULTS

In the base-case analysis, in the CYP2D6*10 testing and alternative adjuvant endocrine therapy group, the incremental total cost was US$17,966.95 and the incremental QALY was 3.582. Thus, the incremental cost-effectiveness ratio was US$5015.693 per QALY gained. Compared with a willingness-to-pay threshold of US$26,508/QALY in China, the CYP2D6*10 testing is the dominant strategy in postmenopausal women with ER-positive breast cancer in China, and the increased cost of genetic testing was completely worthwhile. The sensitivity analyses showed that the model we built was quite stable.

CONCLUSION

From the perspective of the Chinese healthcare system, CYP2D6*10 pharmacogenetic testing was cost effective for postmenopausal women with ER-positive early breast cancer.

Pharmacogenomics of breast cancer: highlighting CYP2D6 and tamoxifen

PURPOSE

To review recent pharmacogenomics studies on breast cancer patients undergoing tamoxifen therapy, highlighting how our knowledge on cytochrome P450 2D6 (CYP2D6) can help to guide the development of adjuvant therapies for these patients.

METHODS

A comprehensive literature search was conducted. Articles reporting findings pertaining to the effect of CYP2D6 on the therapeutic efficacy of tamoxifen, those reporting how targeting CYP2D6 could inform tamoxifen-based therapy development, and those on the tamoxifen effects on cell lines and animal models were included in the review.

RESULTS

With CYP2D6 being the primary enzyme for tamoxifen metabolism, single-nucleotide polymorphisms (SNPs) in this gene were one of the determinants in the rate of tamoxifen metabolism, thereby potentially having an effect on the efficacy of tamoxifen-based therapies. Our review indicates the potential effectiveness of targeting these SNPs, including those for the CYP2D6*10 allele (c. 100C > T), in modifying the level of tamoxifen metabolism. These findings suggest the importance of pharmacogenomics research in our understanding of the efficacy of adjuvant therapies. However, the involvement of multiple enzymes in tamoxifen metabolism, dietary factors, ethnic differences in gene frequencies, and patients' compliance to tamoxifen therapies in studies do present challenges in pharmacogenomics research.

CONCLUSIONS

Pharmacogenomics could play important roles in mediating the advancement of tamoxifen-based adjuvant therapies. Research efforts should be directed towards the exploration of further SNPs of CYP2D6 that affect tamoxifen metabolism, as well as epigenetic changes in CYP2D6, enabling the design of precision medicine and confirming clinical validity in the use of pharmacogenomics for tamoxifen.

CYP2D6*10 pharmacogenetic-guided SERM could be a cost-effective strategy in Chinese patients with hormone receptor-positive breast cancer

Aim: To assess the cost-effectiveness of CYP2D6*10 genetic testing for the management of Chinese women with hormone receptor-positive (HR+) breast cancer treated with selective estrogen receptor modulator. Methods: A Markov model was developed to evaluate a total expected cost and an incremental cost-effectiveness ratio (ICER). Robustness of the model was addressed in one-way analyses and probabilistic sensitivity analysis. Results: The cost of strategies of tamoxifen, toremifene without genotyping and the strategy base on CYP2D6*10 genotype were $63,879.19, $90,156.60 and $95,021.41, and the quality-adjusted life years gained are 8.1588, 12.89687 and 13.85911, respectively. The incremental cost-effectiveness ratio of the CYP2D6*10 testing versus toremifene were 5,055.74221/quality-adjusted life year, respectively. Conclusion: CYP2D6*10 pharmacogenetic-guided selective estrogen receptor modulator can be a cost-effective strategy in the Chinese patients with hormone receptor-positive breast cancer.

Association of CYP2D6*10 (c. 100 C>T) Genotype with Z-END Concentration in Patients with Breast Cancer Receiving Tamoxifen Therapy in Indonesian Population

Background:

Tamoxifen (TAM) is a frequently used hormonal prodrug for patients with breast cancer that needs to be activated by cytochrome P450 2D6 (CYP2D6) into Zusammen-endoxifen (Z-END).

Objective:

The purpose of the study was to determine the association between CYP2D6*10 (c.100C>T) genotype and attainment of the plasma steady-state Z-END minimal threshold concentration (MTC) in Indonesian women with breast cancer.

Methods:

A cross-sectional study was performed in 125 ambulatory patients with breast cancer consuming TAM at 20 mg/day for at least 4 months. The frequency distribution of CYP2D6*10 (c.100C>T) genotypes (C/C: wild type; C/T: heterozygous mutant; T/T: homozygous mutant) was detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), the results of which were subsequently confirmed by sequencing. The genotypes were categorized into plasma Z- END concentrations of <5.9 ng/mL and ≥5.9 ng/mL, which were measured using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

Results:

Percentages of C/C, CT, and T/T genotypes were 22.4%, 29.6%, and 48.8%, respectively. Median (25-75%) Z-END concentrations in C/C, C/T, and T/T genotypes were 9.58 (0.7-6.0), 9.86 (0.7-26.6), and 3.76 (0.9-26.6) ng/mL, respectively. Statistical analysis showed a significant difference in median Z-END concentration between patients with T/T genotype and those with C/C or C/T genotypes (p<0.001). There was a significant association between CYP2D6*10 (c.100C>T) genotypes and attainment of plasma steady-state Z-END MTC (p<0.001).

Conclusion:

There was a significant association between CYP2D6*10 (c.100C>T) and attainment of plasma steady-state Z-END MTC in Indonesian breast cancer patients receiving TAM at a dose of 20 mg/day.

Population genetic difference of pharmacogenomic VIP gene variants in the Lisu population from Yunnan Province

Individual differences in drug clinical response are related to pharmacogenomics. The genetic variation of drug-metabolizing enzymes, drug receptors, and their downstream protein genes is the main factor causing individual differences in drug response. The genetic backgrounds among different ethnic groups are quite different. In this study, we aimed to detect the distribution difference of genotype frequency in very important pharmacogenetic (VIP) gene variants in the Lisu.Using the chi-squared test, we compared the genotype frequencies of the VIP variants in 105 Lisu people with those in 26 populations from the 1000 Genome project separately. Bonferroni's multiple adjustment was also conducted (P < .05/(26*49)). Moreover, Arlequin v3.5 and Structure v2.3.4 software were used to analyze the genetic distance and genetic structure.There were 9, 9, 11, 12, 11, 11, 9, 17, 13, 13, 16, 5, 3, 5, 3, 4, 17, 14, 16, 17, 16, 10, 13, 12, 10, and 9 single nucleotide polymorphisms that differed in frequency distribution, when Lisu people compared with the 26 populations separately. Only CYP2E1 rs2070676 was different in the Lisu population compared with the 26 groups from the 1000 Genome project. PTGS2 rs5275 and CYP2D6 rs1065852 were different in the Lisu population compared with most of the populations. Additionally, genetic backgrounds of Lisu and Han Chinese in Beijing were closest according to the lowest F-statistics value and resemblance in genetic structures.Our results complete the information of the Lisu population in pharmacogenomics database.

Effects of CYP2D6*10 polymorphism on tamoxifen pharmacokinetics in patients with breast cancer in Asia: a meta-analysis

PURPOSE

Insufficient serum metabolite concentrations of tamoxifen can compromise treatment efficacy in patients with breast cancer. The purpose of this meta-analysis was to explore correlations between cytochrome P450 (CYP) 2D6*10 gene polymorphisms and serum concentrations of tamoxifen and its active metabolites in patients with breast cancer in Asia.

METHODS

The study included a systematic literature search for cohort studies published before March 2018 in English databases (PubMed, Embase, Cochrane Library, and Web of Science) and Chinese databases (Chinese National Knowledge Infrastructure and Wan Fang database). The meta-analysis was performed using RevMan 5.3 software. Pooled means and standard deviations were calculated with 95% confidence intervals. Publication bias and sensitivity analyses were also performed using STATA 14.0.

RESULTS

In total, 7 studies and 552 patients were included in the meta-analysis. Serum concentrations of endoxifen were significantly different in each CYP2D6*10 genotype group (p < 0.05). The CC genotype was associated with higher concentrations of 4-OH-TAM than the CT/TT genotype (p < 0.05). However, there were no statistically significant between-group differences in serum concentrations of TAM (p > 0.05). Publication bias and sensitivity analyses confirmed that the meta-analysis results were stable and reliable.

CONCLUSIONS

CYP2D6*10 polymorphisms influence the pharmacokinetics of tamoxifen in patients with breast cancer in Asia.