The influence of single-nucleotide polymorphisms on overall survival and toxicity in cabazitaxel-treated patients with metastatic castration-resistant prostate cancer

SLCO1B1 Polymorphisms are Associated with the Susceptibility to Pulmonary Tuberculosis in Chinese Females

This study aimed to evaluate the role of SLCO1B1 polymorphisms in pulmonary tuberculosis (PTB) risk among Chinese patients. This study comprised 600 PTB patients (mean age: 37.43 ± 12.73 years) and 600 healthy controls (mean age: 37.39 ± 12.57 years) from a Chinese population. The SLCO1B1 rs2306283 and rs4149056 polymorphisms were detected using TaqMan genotyping assay. Chi-square (χ2) test was applied to calculate the Hardy-Weinberg Equilibrium (HWE) among controls. Logistic regression analysis was used to examine the odds ratio (OR) and 95% confidence interval (CI). After adjustment for age and gender, the frequency of rs4149056-C was significantly higher in PTB group (P = 0.017, OR = 1.375, 95% CI 1.058-1.786); meanwhile, rs4149056 was associated with increased PTB risk in dominant model (P = 0.015, OR = 1.424, 95% CI 1.072-1.892). The frequency and genotype of rs2306283 showed no significant difference between the two groups. In stratified analysis, rs2306283-GG showed notable susceptibility to PTB (P = 0.027, OR = 1.563, 95% CI 1.051-2.323 in recessive model) in females; rs4149056-C was also significantly higher in female PTB group (P = 0.039, OR = 1.741, 95% CI 1.028-2.948). Neither of rs2306283 and rs4149056 polymorphisms was associated with PTB risk in males. A haplotype analysis showed that patients carrying at least one SLCO1B1*15 haplotype had higher PTB risk (P = 0.004, OR = 1.527, 95% CI 1.145-2.034). SLCO1B1 polymorphisms are associated with the susceptibility to pulmonary tuberculosis in Chinese females.

A Metabolomics Approach for Predicting OATP1B-Type Transporter-Mediated Drug–Drug Interaction Liabilities

In recent years, various endogenous compounds have been proposed as putative biomarkers for the hepatic uptake transporters OATP1B1 and OATP1B3 that have the potential to predict transporter-mediated drug–drug interactions (DDIs). However, these compounds have often been identified from top–down strategies and have not been fully utilized as a substitute for traditional DDI studies. In an attempt to eliminate observer bias in biomarker selection, we applied a bottom–up, untargeted metabolomics screening approach in mice and found that plasma levels of the conjugated bile acid chenodeoxycholate-24-glucuronide (CDCA-24G) are particularly sensitive to deletion of the orthologous murine transporter Oatp1b2 (31-fold increase vs. wild type) or the entire Oatp1a/1b(−/−)cluster (83-fold increased), whereas the humanized transgenic overexpression of hepatic OATP1B1 or OATP1B3 resulted in the partial restoration of transport function. Validation studies with the OATP1B1/OATP1B3 inhibitors rifampin and paclitaxel in vitro as well as in mice and human subjects confirmed that CDCA-24G is a sensitive and rapid response biomarker to dose-dependent transporter inhibition. Collectively, our study confirmed the ability of CDCA-24G to serve as a sensitive and selective endogenous biomarker of OATP1B-type transport function and suggests a template for the future development of biomarkers for other clinically important xenobiotic transporters.

The role of OATP1B1 and OATP1B3 transporter polymorphisms in drug disposition and response to anticancer drugs: a review of the recent literature

INTRODUCTION

Members of the solute carrier family of organic anion transporting polypeptides are responsible for the cellular uptake of a broad range of endogenous compounds and xenobiotics in multiple tissues. In particular, the polymorphic transporters OATP1B1 and OATP1B3 are highly expressed in the liver and have been identified as critical regulators of hepatic eliminaton. As these transporters are also expressed in cancer cells, the function alteration of these proteins have important consequences for an individual's susceptibility to certain drug-induced side effects, drug-drug interactions, and treatment efficacy.

AREAS COVERED

In this mini-review, we provide an update of this rapidly emerging field, with specific emphasis on the direct contribution of genetic variants in OATP1B1 and OATP1B3 to the transport of anticancer drugs, the role of these carriers in regulation of their disposition and toxicity profiles, and recent advances in attempts to integrate information on transport function in patients to derive individualized treatment strategies.

EXPERT OPINION

Based on currently available data, it appears imperative that different aspects of disease, physiology, and drugs of relevance should be evaluated along with an individual's genetic signature, and that tools such as biomarker levels can be implemented to achieve the most reliable prediction of clinically relevant pharmacodynamic endpoints.

Single-nucleotide polymorphism associations with efficacy and toxicity in metastatic castration-resistant prostate cancer treated with cabazitaxel

Background: The aim of this study was to evaluate the impact of certain single-nucleotide polymorphisms (SNPs) in cabazitaxel activity and toxicity in patients with metastatic castration-resistant prostate cancer (mCRPC). Patients & methods: 56 SNPs in five genes (CYP3A4, CYP3A5, ABCB1, TUBB1 and CYP2C8) were genotyped in 67 mCRPC patients and their correlation with outcomes analyzed. Results: TUBB1-rs151352 (hazard ratio: 0.52) and CYP2C8-rs1341164 (hazard ratio: 0.53) were associated with better overall survival, and CYP2C8-rs1058932 with biochemical progression (odds ratio: 6.60) in multivariate analysis. ABCB1-rs17327624 correlated with severe toxicity ≥ grade 3 (odds ratio: 8.56) and CYP2C8-rs11572093 with asthenia (odds ratio: 8.12). Conclusion: Genetic variants in mCRPC patients could explain different outcomes with cabazitaxel. Nonetheless, the small sample size and the high number of SNPs analyzed mean that the results are only hypothesis-generating and require further validation.

APOE gene ɛ4 allele (388C-526C) effects on serum lipids and risk of coronary artery disease in southern Chinese Hakka population

OBJECTIVE

To analyze the relationship of Apolipoprotein E (APOE) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) gene polymorphisms with coronary artery disease (CAD).

METHODS

1,129 CAD patients and 1,014 non-CAD controls were included in the study, and relevant information and medical records were collected. The single-nucleotide polymorphisms (SNPs) were analyzed, including rs429358, rs7412 in APOE gene and rs2306283, rs4149056 in SLCO1B1 gene.

RESULTS

The CAD patients' average age was 66.3 ± 10.7 years, while 65.5 ± 12.0 years in controls. The frequencies of APOE allele ɛ3, ɛ4, and ɛ2 were 83.01%, 10.08%, and 6.91% respectively. There were statistically significant differences in genotype ɛ3/ɛ4 (χ²  = 8.077, p = 0.005) in CAD patients compared with the controls. The SLCO1B1 genotype *1b/*1b and haplotype *1b showed the highest frequency in the study sample. Moreover, ε4 carriers had significantly lower HDL-C, Apo-A1 levels than ε3 carriers among CAD patients, while ε2 carriers showed lower LDL-C, Apo-B level, and higher Apo-A1/Apo-B level than ε3 and ε4 carriers. In controls, ε2 carriers showed lower LDL-C and Apo-B level, higher Apo-A1, and Apo-A1/Apo-B level than ε4 carriers. Logistic regression analysis showed that high LDL-C and Apo-B level, low HDL-C level, smoking, and the ε4 allele were risks for the presence of CAD.

CONCLUSIONS

APOE ε4 allele may be associated with susceptibility to CAD in southern Chinese Hakka population. It indicated that the APOE SNPs rs429358 and rs7412 are associated with CAD, but not SNPs rs2306283 and rs4149056 of SLCO1B1 gene.

Long-Term Prostate-Specific Antigen Response on a Low-Dose Cabazitaxel Regimen for Metastatic Castration-Resistant Prostate Cancer: A Case Report

BACKGROUND Cabazitaxel is a second-generation taxane approved for patients with metastatic castration-resistant prostate cancer (CRPC). Although cabazitaxel improves overall survival when used following docetaxel chemotherapy, duration of the clinical response is relatively short, and few patients achieve a long-term response. CASE REPORT A 71-year-old man with prostate adenocarcinoma with an initial prostate-specific antigen (PSA) level of 4956 ng/ml, Gleason score 4+5 and cTxN0M1b was referred to our department for treatment. Several therapeutic approaches, including androgen deprivation therapy, with a combination of bicalutamide and a luteinizing hormone-releasing hormone analogue, and 4 sequential hormonal therapies including flutamide, estramustine, enzalutamide, and abiraterone, all failed to prevent disease progression. Subsequently, after 5 cycles of docetaxel chemotherapy were also ineffective, cabazitaxel chemotherapy at a dose of 20 mg/m² together with prednisone and pegfilgrastim was initiated. The patient developed grade 4 thrombocytopenia during the first 4 cycles, and the dosage of cabazitaxel had to be tapered to 12.5 mg/m² by the fifth cycle. In subsequent cycles, the treatment was continued without grade 4 thrombocytopenia or any other toxicities ³grade 3. The patient achieved a long-term clinical response over 4 years and his PSA level continued to decrease, from 29.8 ng/ml at treatment initiation to a nadir of 2.0 ng/ml after the 60th cycle. CONCLUSIONS The present case is a rare example of a sustained response to low-dose cabazitaxel, and suggests its potential as a treatment option for metastatic CRPC patients. In our patient, this approach achieved a good clinical response with manageable toxicity over the long term.

Genetic Polymorphisms and Pharmacotherapy for Prostate Cancer

The therapeutic landscape of pharmacotherapy for prostate cancer has dramatically evolved, and multiple therapeutic options have become available for prostate cancer patients. Therefore, useful biomarkers to identify suitable candidates for treatment are required to maximize the efficacy of pharmacotherapy. Genetic polymorphisms such as single-nucleotide polymorphisms (SNPs) and tandem repeats have been shown to influence the therapeutic effects of pharmacotherapy for prostate cancer patients. For example, genetic polymorphisms in the genes involved in androgen receptor signaling are reported to be associated with the therapeutic outcome of androgen-deprivation therapy as well as androgen receptor-pathway inhibitors. In addition, SNPs in genes involved in drug metabolism and efflux pumps are associated with therapeutic effects of taxane chemotherapy. Thus, genetic polymorphisms such as SNPs are promising biomarkers to realize personalized medicine. Here, we overview the current findings on the influence of genetic polymorphisms on the outcome of pharmacotherapy for prostate cancer and discuss current issues as well as future visions in this field.

The SNPs rs429358 and rs7412 of APOE gene are association with cerebral infarction but not SNPs rs2306283 and rs4149056 of SLCO1B1 gene in southern Chinese Hakka population

Background

Apolipoprotein E (ApoE) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) regulate lipid metabolism. However, the relationship between genetic polymorphisms of APOE and SLCO1B1 and cerebral infarction (CI) remains unclear.

Methods

A total of 938 CI patients and 1028 control participants were included in the study. The rs429358 and rs7412 single nucleotide polymorphisms (SNPs) in the APOE gene and rs2306283 and rs4149056 SNPs in the SLCO1B1 gene were analyzed by fluorescence polymerase chain reaction (PCR).

Results

The genotype ɛ3/ɛ3 was the most common APOE genotype, with ɛ3 being the allele with the highest frequency, followed by ɛ4 and ɛ2. Statistically significant differences of genotype ɛ2/ɛ2 (χ² = 3.866, P = 0.049), ɛ2/ɛ3 (χ² = 20.030, P < 0.001), ɛ3/ɛ4 (χ² = 16.960, P < 0.001), and ɛ4/ɛ4 (χ² = 4.786, P = 0.029) between CI patients and controls were detected. The SLCO1B1 genotype *1b/*1b and haplotype *1b showed the highest frequency in the study sample. There was no statistically significant difference in the frequencies of SLCO1B1 genotypes and haplotypes among CI patients comparing with controls. Moreover, ε4 carriers had significantly higher low-density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (Apo-B) and lower apolipoprotein A1 (Apo-A1)/Apo-B levels than ε2 and ε3 carriers, but ε2 carriers showed lower LDL-C and Apo-B and higher Apo-A1/Apo-B than ε3 and ε4 carriers. Further, logistic regression analysis revealed that high LDL-C, high ApoB, smoking, hypertension and the ε4 allele were risks for the presence of CI.

Conclusions

This study indicated that the APOE SNPs rs429358 and rs7412 may be associated with susceptibility to cerebral infarction in southern Chinese Hakka population.