Pharmacogenetics of toxicity of 5-fluorouracil, doxorubicin and cyclophosphamide chemotherapy in breast cancer patients

CPMKG: a condition-based knowledge graph for precision medicine

Personalized medicine tailors treatments and dosages based on a patient's unique characteristics, particularly its genetic profile. Over the decades, stratified research and clinical trials have uncovered crucial drug-related information-such as dosage, effectiveness, and side effects-affecting specific individuals with particular genetic backgrounds. This genetic-specific knowledge, characterized by complex multirelationships and conditions, cannot be adequately represented or stored in conventional knowledge systems. To address these challenges, we developed CPMKG, a condition-based platform that enables comprehensive knowledge representation. Through information extraction and meticulous curation, we compiled 307 614 knowledge entries, encompassing thousands of drugs, diseases, phenotypes (complications/side effects), genes, and genomic variations across four key categories: drug side effects, drug sensitivity, drug mechanisms, and drug indications. CPMKG facilitates drug-centric exploration and enables condition-based multiknowledge inference, accelerating knowledge discovery through three pivotal applications. To enhance user experience, we seamlessly integrated a sophisticated large language model that provides textual interpretations for each subgraph, bridging the gap between structured graphs and language expressions. With its comprehensive knowledge graph and user-centric applications, CPMKG serves as a valuable resource for clinical research, offering drug information tailored to personalized genetic profiles, syndromes, and phenotypes. Database URL: https://www.biosino.org/cpmkg/.

Cyclophosphamide Pharmacogenomic Variation in Cancer Treatment and Its Effect on Bioactivation and Pharmacokinetics

Cyclophosphamide (Cy) is a prodrug that is mainly bioactivated by cytochrome P450 (CYP) 2B6 enzyme. Several other enzymes are also involved in its bioactivation and affect its kinetics. Previous studies have shown the effect of the enzymes' genetic polymorphisms on Cy kinetics and its clinical outcome. These results were controversial primarily because of the involvement of several interacting enzymes in the Cy metabolic pathway, which can also be affected by several clinical factors as well as other drug interactions. In this review article, we present the effect of CYP2B6 polymorphisms on Cy kinetics since it is the main bioactivating enzyme, as well as discussing all previously reported enzymes and clinical factors that can alter Cy efficacy. Additionally, we present explanations for key Cy side effects related to the nature and site of its bioactivation. Finally, we discuss the role of busulphan in conditioning regimens in the Cy metabolic pathway as a clinical example of drug-drug interactions involving several enzymes. By the end of this article, our aim is to have provided a comprehensive summary of Cy pharmacogenomics and the effect on its kinetics. The utility of these findings in the development of new strategies for Cy personalized patient dose adjustment will aid in the future optimization of patient specific Cy dosages and ultimately in improving clinical outcomes. In conclusion, CYP2B6 and several other enzyme polymorphisms can alter Cy kinetics and consequently the clinical outcomes. However, the precise quantification of Cy kinetics in any individual patient is complex as it is clearly under multifactorial genetic control. Additionally, other clinical factors such as the patient's age, diagnosis, concomitant medications, and clinical status should also be considered.

Effects of pharmacogenetics on pharmacokinetics and toxicity of doxorubicin in Egyptian breast cancer patients

This study investigates the impact of single nucleotide polymorphisms in genes (SLC22A16 and CBR1) involved in the pharmacokinetics and toxicity of doxorubicin (DOX) in Egyptian female patients with breast cancer.Patients administered DOX (60 mg/m2) for 4 cycles every 3 weeks. The peak DOX plasma concentration was measured using a validated chromatographic method. The genotyping for the selected SNPs, SLC22A16 T > C (rs714368), and CBR1 C > T (rs20572), was performed by RT-PCR. Patients were monitored for hematological and cardiac toxicities.The variant carriers of CBR1 C > T (rs20572) exhibited significantly higher DOX concentration, but no significant association to DOX-induced hematological toxicity. On the other hand, SLC22A16 T > C (rs714368) had no significant influence on DOX plasma concentration, but was significantly correlated with lower risk of neutropenia (OR 0.31, 95% CI 0.12-0.75, p = 0.01) and leukopoenia (OR 0.18, 95% CI 0.07-0.5, p = 0.001). DOX-related cardiotoxicity was correlated with the cumulative dose of DOX (R = 0.238, p = 0.017), but not with any of the two examined SNPs.Genetic polymorphisms in SLC22A16 and CBR1 may explain the inter-individual variations in DOX pharmacokinetics and toxicity. Using pharmacogenetic testing is important to customise drug therapy for cancer patients treated with anthracyclines.

Pharmacogenomic-guided dosing of fluoropyrimidines beyond DPYD: time for a polygenic algorithm?

Fluoropyrimidines are chemotherapeutic agents widely used for the treatment of various solid tumors. Commonly prescribed FPs include 5-fluorouracil (5-FU) and its oral prodrugs capecitabine (CAP) and tegafur. Bioconversion of 5-FU prodrugs to 5-FU and subsequent metabolic activation of 5-FU are required for the formation of fluorodeoxyuridine triphosphate (FdUTP) and fluorouridine triphosphate, the active nucleotides through which 5-FU exerts its antimetabolite actions. A significant proportion of FP-treated patients develop severe or life-threatening, even fatal, toxicity. It is well known that FP-induced toxicity is governed by genetic factors, with dihydropyrimidine dehydrogenase (DPYD), the rate limiting enzyme in 5-FU catabolism, being currently the cornerstone of FP pharmacogenomics. DPYD-based dosing guidelines exist to guide FP chemotherapy suggesting significant dose reductions in DPYD defective patients. Accumulated evidence shows that additional variations in other genes implicated in FP pharmacokinetics and pharmacodynamics increase risk for FP toxicity, therefore taking into account more gene variations in FP dosing guidelines holds promise to improve FP pharmacotherapy. In this review we describe the current knowledge on pharmacogenomics of FP-related genes, beyond DPYD, focusing on FP toxicity risk and genetic effects on FP dose reductions. We propose that in the future, FP dosing guidelines may be expanded to include a broader ethnicity-based genetic panel as well as gene*gene and gender*gene interactions towards safer FP prescription.

GPR19 Coordinates Multiple Molecular Aspects of Stress Responses Associated with the Aging Process

G protein-coupled receptors (GPCRs) play a significant role in controlling biological paradigms such as aging and aging-related disease. We have previously identified receptor signaling systems that are specifically associated with controlling molecular pathologies associated with the aging process. Here, we have identified a pseudo-orphan GPCR, G protein-coupled receptor 19 (GPR19), that is sensitive to many molecular aspects of the aging process. Through an in-depth molecular investigation process that involved proteomic, molecular biological, and advanced informatic experimentation, this study found that the functionality of GPR19 is specifically linked to sensory, protective, and remedial signaling systems associated with aging-related pathology. This study suggests that the activity of this receptor may play a role in mitigating the effects of aging-related pathology by promoting protective and remedial signaling systems. GPR19 expression variation demonstrates variability in the molecular activity in this larger process. At low expression levels in HEK293 cells, GPR19 expression regulates signaling paradigms linked with stress responses and metabolic responses to these. At higher expression levels, GPR19 expression co-regulates systems involved in sensing and repairing DNA damage, while at the highest levels of GPR19 expression, a functional link to processes of cellular senescence is seen. In this manner, GPR19 may function as a coordinator of aging-associated metabolic dysfunction, stress response, DNA integrity management, and eventual senescence.

Toxicity and Impact of Silica Nanoparticles on the Configuration of Gut Microbiota in Immunodeficient Mice

Nanoparticles (NPs), having exceptional physicochemical and electrical characteristics with lower toxicity, have evolved as dynamic drug delivery carriers in living organisms. Potentially, the intragastric gavage of silica nanoparticles (SiNPs) affects gut microbiota profiles in immunodeficient mice. In this study, the impact of SiNPs of variable size and dosage was investigated in cyclophosphamide (Cy)-induced immunodeficient mice, specifically on their immune functions and gut microbiota, through physicochemical and metagenomic analysis. SiNPs of different sizes and doses were gavaged to Cy-induced immunodeficient mice for 12 days at an interval of 24 h to investigate their effects on immunological functions and the gut microbiome of mice. Our results showed that SiNPs had no significant toxicological effects on the cellular and hematological activities of immunodeficient mice. Furthermore, after the administration of different levels of SiNPs, no immune dysfunction was found in the immunosuppressed mice groups. However, gut-microbial studies and comparisons of characteristic bacterial diversity and compositions demonstrated that SiNPs significantly affect the abundance of different bacterial communities. LEfSe analysis revealed that SiNPs significantly increased the abundance of Lactobacillus, Sphingomonas, Sutterella, Akkermansia, and Prevotella, and potentially reduced Ruminococcus and Allobaculum. Thus, SiNPs significantly regulate and modify the configuration of the gut microbiota in immunodeficient mice. These dynamic variations in the intestinal bacterial community, abundance, and diversity provide new insight into the regulation and administration of silica-based NPs. This would be helpful for the further demonstration of the mechanism of action and prediction of the potential effects of SiNPs.

Multi-Drug Resistance against Second-Line Medication and MicroRNA Plasma Level in Metastatic Breast Cancer Patients

Background

Circulating microRNAs (miRNAs) can help to predict the chemotherapy response in breast cancer with promising results. The aim of the present study was to investigate the relationships between the miR-199a, miR-663a, and miR-663b expression and chemotherapy response in metastatic breast cancer patients.

Methods

This study is a case-control study performed at Yasuj University of Medical Sciences (2018-2021). The expression levels of miR-663a, miR-663b, and miR-199a in the serum of 25 patients with metastatic breast cancer versus 15 healthy individuals were determined by the real-time polymerase chain reaction method. The response to treatment was followed up in a 24-month period. All patients were treated with second-line medications. Two or more combinations of these drugs were used: gemcitabine, Navelbine^®, Diphereline^®, Xeloda^®, letrozole, Aromasin^®, and Zolena^®. Statistical analyses were performed in SPSS 21.0 and GraphPad Prism 6 software. The expression levels were presented as mean±SD and analyzed by Student's t test.

Results

The results and clinicopathological features of patients were analyzed by t test. The statistical analysis showed that miR-663a expression was related to human epidermal growth factor receptor 2 (HER2) status and was significantly lower in the HER2⁺ than HER2^- group (P=0.027). Moreover, the expression of miR-199a and miR-663b was significantly correlated with the response to treatment, in which the expression of miR-199a was higher in the poor-response group (P=0.049), while the higher expression of miR-663b was seen in the good-response group (P=0.009).

Conclusion

These findings state that the high plasma level of miR-199a and the low plasma level of miR-663b may be related to chemoresistance in patients with metastatic breast cancer.

Breast cancer pharmacogenetics: a systematic review

Breast cancer was declared the most prevalent type of cancer in 2020. Among other factors, treatment response can be affected by genetic polymorphisms - which is the focus of pharmacogenetics - and ethnicity is also a contributing factor in this context. Relevant genes in disease treatment pathways were selected to evaluate treatment response from the pharmacogenetic perspective; polymorphism frequencies and ethnic and continental representation across the available literature were also assessed through a systematic review. The identified associations and gaps have been described in this study with the purpose that, in the future, treatments can be personalized and thus be more effective, safer, and accessible to all.

Pharmacogenetics of Drug Metabolism: The Role of Gene Polymorphism in the Regulation of Doxorubicin Safety and Efficacy

Simple Summary

The effectiveness and safety of the anti-cancer agent doxorubicin (anthracycline group medicine) depend on the metabolism and retention of the drug in the human organism. Polymorphism of cytochrome p450 (CYP)-encoding genes and detoxifying enzymes such as CYP3A4 and CYP2D6 were found responsible for variations in the doxorubicin metabolism. Transmembrane transporters such as p-glycoproteins were reported to be involved in cancer tissue retention of doxorubicin. ATP-binding cassette (ABC) family members, including ABCB1 transporters (also known as Multi-Drug Resistance 1 (MDR1)) proteins, were determined to pump out doxorubicin from breast cancer cells, therefore reducing the drug effectiveness. This study critically discusses the latest data about the role of CYP3A4, CYP2D6, and ABCB1 gene polymorphism in the regulation of doxorubicin’s effects in breast cancer patients. The assessment of genetic differences in the expression of doxorubicin metabolizing and transporting enzymes should be explored for the development of personalized medical treatment of breast cancer patients.

Abstract

Breast cancer (BC) is the prevailing malignancy and major cause of cancer-related death in females. Doxorubicin is a part of BC neoadjuvant and adjuvant chemotherapy regimens. The administration of anthracycline derivates, such as doxorubicin, may cause several side effects, including hematological disfunction, gastrointestinal toxicity, hepatotoxicity, nephrotoxicity, and cardiotoxicity. Cardiotoxicity is a major adverse reaction to anthracyclines, and it may vary depending on individual differences in doxorubicin pharmacokinetics. Determination of specific polymorphisms of genes that can alter doxorubicin metabolism was shown to reduce the risk of adverse reactions and improve the safety and efficacy of doxorubicin. Genes which encode cytochrome P450 enzymes (CYP3A4 and CYP2D6), p-glycoproteins (ATP-binding cassette (ABC) family members such as Multi-Drug Resistance 1 (MDR1) protein), and other detoxifying enzymes were shown to control the metabolism and pharmacokinetics of doxorubicin. The effectiveness of doxorubicin is defined by the polymorphism of cytochrome p450 and p-glycoprotein-encoding genes. This study critically discusses the latest data about the role of gene polymorphisms in the regulation of doxorubicin’s anti-BC effects. The correlation of genetic differences with the efficacy and safety of doxorubicin may provide insights for the development of personalized medical treatment for BC patients.

Pharmacogenetic Variation and Its Clinical Relevance in a Latin American Rural Population

Latin-American populations have been largely underrepresented in genomic studies of drug response and disease susceptibility. In this paper, we present a genome-wide Chilean dataset from Talca based on the Illumina Global Screening Array. This let us to compare the frequency of gene variants involved in response to drugs among our population and others, taking data from the 1000 Genomes Project. We found four single-nucleotide polymorphisms with low prevalence in Chileans when compared with African, Amerindian, East and South Asian, and European populations: rs2819742 (RYR2), rs2631367 (SLC22A5), rs1063320 (HLA-G), and rs1042522 (TP53). Moreover, two markers showed significant differences between lower and higher proportion of Mapuche ancestry groups: rs1719247 (located in an intergenic region in chromosome 15; p-value = 6.17 × 10⁻⁵, Bonferroni corrected p-value = 0.02) and rs738409 (A nonsynonymous gene variant in the PNPLA3 gene; p-value = 9.02 × 10⁻⁵, Bonferroni corrected p-value = 0.04). All of these polymorphisms have been shown to be associated with diverse pathologies, such as asthma, cancer, or chronic hepatitis B, or to be involved in a different response to drugs, such as metformin, HMG-CoA reductase inhibitors, or simvastatin. The present work provides a pharmacogenetic landscape of an understudied Latin American rural population and supports the notion that pharmacogenetic studies in admixed populations should consider ancestry for a higher accuracy of the results. Our study stresses the relevance of the pharmacogenomic research to provide guidance for a better choice of the best treatment for each individual in a population with admixed ancestry.

Synergistic effect of antimetabolic and chemotherapy drugs in triple-negative breast cancer

The triple-negative breast cancer (TNBC) subtype comprises approximately 15% of all breast cancers and is associated with poor long-term outcomes. Classical chemotherapy remains the standard of treatment, with toxicity and resistance being major limitations. TNBC is a high metabolic group, and antimetabolic drugs are effective in inhibiting TNBC cell growth. We analyzed the combined effect of chemotherapy and antimetabolic drug combinations in MDA-MB-231, MDA-MB-468 and HCC1143 human TNBC cell lines. Cells were treated with each drug or with drug combinations at a range of concentrations to establish the half-maximal inhibitory concentrations (IC₅₀). The dose-effects of each drug or drug combination were calculated, and the synergistic or antagonistic effects of drug combinations were defined. Chemotherapy and antimetabolic drugs exhibited growth inhibitory effects on TNBC cell lines. Antimetabolic drugs targeting the glycolysis pathway had a synergistic effect with chemotherapy drugs, and antiglycolysis drug combinations also had a synergistic effect. The use of these drug combinations could lead to new therapeutic strategies that reduce chemotherapy drug doses, decreasing their toxic effect, or that maintain the doses but enhance their efficacy by their synergistic effect with other drugs.

Pharmacogenetic Profiling in High-Risk Soft Tissue Sarcomas Treated with Neoadjuvant Chemotherapy

Neoadjuvant chemotherapy based on anthracyclines and ifosfamide for high-risk soft tissue sarcomas (STS) of the extremities and trunk is a controversial treatment option. There are substantial interindividual differences in clinical outcomes in patients treated with neoadjuvant chemotherapy. The aim of this study was to evaluate, as biomarkers, polymorphisms in genes encoding drug-metabolizing enzymes, drug transporters, or drug targets and their association with toxicity and survival in STS patients treated with neoadjuvant chemotherapy. We analysed variants in genes involved in anthracycline metabolism (ABCB1, ABCC2, NQO1, CBR3, and SLC22A16) and in ifosfamide catabolism (ALDH1A1) in 79 treated patients. Two genes showed significant association after adjusted multivariate analysis: ABCC2 and ALDH1A1. In patients treated with anthracyclines, ABCC2 rs3740066 was associated with risk of febrile neutropenia (p = 0.031), and with decreased overall survival (OS) (p = 0.024). ABCC2 rs2273697 was associated with recurrence-free survival (RFS) (p = 0.024). In patients treated with ifosfamide, ALDH1A1 rs3764435 was associated with RFS (p = 0.046). Our pharmacogenetic study shows for the first time that variants in genes regulating the metabolism of neoadjuvant chemotherapy may be helpful to predict toxicity and survival benefit in high-risk STS treated with neoadjuvant chemotherapy. Further validation studies are needed to establish their clinical utility.

Exosomes as Emerging Drug Delivery and Diagnostic Modality for Breast Cancer: Recent Advances in Isolation and Application

Breast cancer (BC) is the most common type of malignancy which covers almost one-fourth of all the cancers diagnosed in women. Conventionally, chemo-, hormonal-, immune-, surgery, and radiotherapy are the clinically available therapies for BC. However, toxicity and other related adverse effects are still the major challenges. A variety of nano platforms have been reported to overcome these limitations, among them, exosomes provide a versatile platform not only for the diagnosis but also as a delivery vehicle for drugs. Exosomes are biological nanovesicles made up of a lipidic bilayer and known for cell-to-cell communication. Exosomes have been reported to be present in almost all bodily fluids, viz., blood, milk, urine, saliva, pancreatic juice, bile, peritoneal, and cerebrospinal fluid. Such characteristics of exosomes have attracted immense interest in cancer diagnosis and therapy. They can deliver bioactive moieties such as protein, lipids, hydrophilic as well as hydrophobic drugs, various RNAs to both distant and nearby recipient cells as well as have specific biological markers. By considering the growing interest of the scientific community in this field, we comprehensively compiled the information about the biogenesis of exosomes, various isolation methods, the drug loading techniques, and their diverse applications in breast cancer diagnosis and therapy along with ongoing clinical trials which will assist future scientific endeavors in a more organized direction.

The correlation between the level of 3-hydroxypropyl mercapturic acid, CYP2B6 polymorphisms, and hematuria occurrences after cyclophosphamide administration and its bioanalytical methods: A systematic review

BACKGROUND

Cyclophosphamide (CPA) is a cytotoxic prodrug that needs to be metabolized by cytochrome P450 enzymes, like CYP2B6. Unfortunately, CYP2B6 is a very polymorphic enzyme and can cause a change in 3-hydroxypropyl mercapturic acid (3-HPMA), the most found CYP metabolite in urine levels. Change in 3-HPMA levels can also indicate the level change in its precursor, acrolein, which is responsible for the hematuria incidence after CPA administration.This review's purpose is to obtain a conclusion about the optimal 3-HPMA analysis method in urine after the administration of cyclophosphamide using liquid chromatography-tandem mass spectrometry (LC-MS/MS) through literature review from previous studies. Also, this review was written to examine the relationship between levels of 3-HPMA in urine, polymorphisms of CYP2B6 enzymes, and the incidence of hematuria after cyclophosphamide administration in cancer patients.

METHODS

Major databases, such as Universitas Indonesia's library database ScienceDirect, PubMed/Medline, Frontiers Media, and Google Scholar database, were used to find both published and unpublished studies without a time limit until 2020. Studies on pharmacokinetics, pharmacodynamics, drug therapy monitoring of cyclophosphamide, bioanalysis, and polymerase chain reaction (PCR) published in Indonesian and English were included. Meanwhile, non-related studies or studies written in other languages besides Indonesian and English were excluded. Two independent reviewers screened the titles, abstracts, and full-text manuscripts. Data obtained from eligible sources were used to answer the purpose of this review in a narrative form.

RESULTS

The authors found 436 related studies from various databases and websites. Then, the authors narrowed it down into 62 pieces of literature by removing the duplicates and reviewing the abstracts and full-text manuscripts. Out of 62 sources, the authors found 30 studies that explained 3-HPMA analysis using LC/MS-MS, CYP2B6 polymorphisms, and hematuria occurrences. The authors used those 30 studies to build a conclusion regarding the purpose of this study. We strengthened the results with some additional information from the other 32 eligible sources.

CONCLUSIONS

The authors conclude that according to literature searches from previous studies, the optimal 3-HPMA analysis method in urine after cyclophosphamide administration using LC-MS/MS is using triple quadrupole LC-MS/MS; source of positive ion electrospray ionization (ESI); mobile phase combination of 0.1% formic acid in water (A) - 0.1% formic acid in acetonitrile (90:10 v/v) (B); the Acquity® BEH C18 column (2.1 × 100 mm; 1.7 μm); injection volume of 10 μl; flow rate of 0.2 ml/minute; gradient elution method. Detection was carried out using mass spectrometry with m/z ratio of 222.10 > 90 for 3-HPMA and m/z 164.10 > 122 for n-acetylcysteine (NAC). The optimum sample preparation method is acidification and dilution ratio of 1:5 v/v. Also, there is a relationship between 3-HPMA levels, CYP2B6 polymorphisms, and the occurrences of hematuria after the administration of cyclophosphamide, which is a type of CYP2B6 polymorph, namely CYP2B6∗6, can increase cyclophosphamide hydroxylation so that it can increase the levels of acrolein and 3-HPMA, as its metabolites, and risk of hematuria.

ETHICS AND DISSEMINATION

This research does not use human participants, human data, or human tissue for being directly studied for the review. Therefore, ethics approval and consent to participate are not applicable.

REGISTRATION

This research has not been registered yet.

Effect of Genetic Variation in CYP450 on Gonadal Impairment in a European Cohort of Female Childhood Cancer Survivors, Based on a Candidate Gene Approach: Results from the PanCareLIFE Study

BACKGROUND

Female childhood cancer survivors (CCSs) carry a risk of therapy-related gonadal dysfunction. Alkylating agents (AA) are well-established risk factors, yet inter-individual variability in ovarian function is observed. Polymorphisms in CYP450 enzymes may explain this variability in AA-induced ovarian damage. We aimed to evaluate associations between previously identified genetic polymorphisms in CYP450 enzymes and AA-related ovarian function among adult CCSs.

METHODS

Anti-Müllerian hormone (AMH) levels served as a proxy for ovarian function in a discovery cohort of adult female CCSs, from the pan-European PanCareLIFE cohort (n = 743; age (years): median 25.8, interquartile range (IQR) 22.1-30.6). Using two additive genetic models in linear and logistic regression, nine genetic variants in three CYP450 enzymes were analyzed in relation to cyclophosphamide equivalent dose (CED) score and their impact on AMH levels. The main model evaluated the effect of the variant on AMH and the interaction model evaluated the modifying effect of the variant on the impact of CED score on log-transformed AMH levels. Results were validated, and meta-analysis performed, using the USA-based St. Jude Lifetime Cohort (n = 391; age (years): median 31.3, IQR 26.6-37.4).

RESULTS

CYP3A4*3 was significantly associated with AMH levels in the discovery and replication cohort. Meta-analysis revealed a significant main deleterious effect (Beta (95% CI): -0.706 (-1.11--0.298), p-value = 7 × 10-4) of CYP3A4*3 (rs4986910) on log-transformed AMH levels. CYP2B6*2 (rs8192709) showed a significant protective interaction effect (Beta (95% CI): 0.527 (0.126-0.928), p-value = 0.01) on log-transformed AMH levels in CCSs receiving more than 8000 mg/m2 CED.

CONCLUSIONS

Female CCSs CYP3A4*3 carriers had significantly lower AMH levels, and CYP2B6*2 may have a protective effect on AMH levels. Identification of risk-contributing variants may improve individualized counselling regarding the treatment-related risk of infertility and fertility preservation options.

Effects of Low-Intensity Pulsed Ultrasound on Myelosuppression of Rats Induced by Chemotherapy Drugs With Cell Cycle Specificity

OBJECTIVES

To explore the ameliorating effects of low-intensity pulsed ultrasound (LIPUS) on Sprague Dawley rat myelosuppression induced by cell cycle specificity drugs (docetaxel, mitotic phase sensitive; and etoposide, gap 2 phase sensitive).

METHODS

Rats were respectively administered docetaxel (100 mg/kg) or etoposide (110 mg/kg) by intraperitoneal injection for 4 consecutive days. Then the rats were divided randomly into a LIPUS group and a non-LIPUS group. In the LIPUS group, the right femoral metaphysis of rats was treated by LIPUS (acoustic intensity, 200 mW/cm² ; frequency, 0.3 MHz; and duty cycle, 20%) for 20 minutes on 7 consecutive days from day 5. The rats of the non-LIPUS group were treated without ultrasound output. A blood cell count, an enzyme-linked immunosorbent assay, a real-time quantitative polymerase chain reaction, and hematoxylin-eosin staining were applied to detect the results.

RESULTS

Low-intensity pulsed ultrasound significantly promoted the counts of bone marrow nucleated cells, white blood cells, immunoglobulin A (IgA), IgG, granulocyte colony-stimulating factor, stem cell factor, and intercellular cell adhesion molecule 1 and reduced the counts of vascular cell adhesion molecule 1 whether in the docetaxel or etoposide group (P < .05). Low-intensity pulsed ultrasound only increased the expression level of IgM in the docetaxel group but decreased the level of interleukin 6 in the etoposide group (P < .05).

CONCLUSIONS

Low-intensity pulsed ultrasound has potential to be a noninvasive treatment for myelosuppression caused by different cell cycle-sensitive chemotherapy drugs.

Calotropis gigantea stem bark extract induced apoptosis related to ROS and ATP production in colon cancer cells

Conventional chemotherapeutic agents for colorectal cancer (CRC) cause systemic side effects and eventually become less efficacious owing to the development of drug resistance in cancer cells. Therefore, new therapeutic regimens have focused on the use of natural products. The anticancer activity of several parts of Calotropis gigantea has been reported; however, the effects of its stem bark extract on inhibition of cancer cell proliferation have not yet been examined. In this study, the anticancer activity of C. gigantea stem bark extract, both alone and in combination with 5-fluorouracil (5-FU), was evaluated. A crude ethanolic extract was prepared from dry, powdered C. gigantea barks using 95% ethanol. This was then partitioned to obtain dichloromethane (CGDCM), ethyl acetate, and water fractions. Quantitative analysis of the constituent secondary metabolites and calotropin was performed. These fractions exhibited cytotoxicity in HCT116 and HT-29 cells, with CGDCM showing the highest potency in both the cell lines. A combination of CGDCM and 5-FU significantly enhanced the cytotoxic effect. Moreover, the resistance of normal fibroblast, HFF-1, cells to this combination demonstrated its safety in normal cells. The combination significantly enhanced apoptosis through the mitochondria-dependent pathway. Additionally, the combination reduced adenosine triphosphate production and increased the production of reactive oxygen species, demonstrating the mechanisms involved in the induction of apoptosis. Our results suggest that CGDCM is a promising anti-cancer agent and may enhance apoptosis induction by 5-FU in the treatment of CRC, while minimizing toxicity toward healthy cells.

Shining light on single-strand lesions caused by the chemotherapy drug bleomycin

Quantification of the DNA damage induced by chemotherapy in patient cells may aid in personalization of the dose used. However, assays to evaluate individual patient response to chemotherapy are not available today. Here, we present an assay that quantifies single-stranded lesions caused by the chemotherapeutic drug Bleomycin (BLM) in peripheral blood mononuclear cells (PBMCs) isolated from healthy individuals. We use base excision repair (BER) enzymes to process the DNA damage induced by BLM and then extend the processed sites with fluorescent nucleotides using a DNA polymerase. The fluorescent patches are quantified on single DNA molecules using fluorescence microscopy. Using the assay, we observe a significant variation in the in vitro induced BLM damage and its repair for different individuals. Treatment of the cells with the BER inhibitor CRT0044876 leads to a lower level of repair of BLM-induced damage, indicating the ability of the assay to detect a compromised DNA repair in patients. Overall, the data suggest that our assay could be used to sensitively detect the variation in BLM-induced DNA damage and repair in patients and can potentially be able to aid in personalizing patient doses.

Gender-dependent association of TYMS-TSER polymorphism with 5-fluorouracil or capecitabine-based chemotherapy toxicity

Aim: TYMS gene encodes for TS enzyme involved in 5-fluorouracil (5-FU) and capecitabine (CAP) metabolism. This study assessed the association of TYMS-TSER and 3RG>C polymorphisms with 5-FU/CAP adverse event (AE) incidence. Materials & methods: TYMS-TSER and 3RG>C polymorphisms were analyzed by use of PCR/PCR-RFLP in 313 5-FU/CAP-treated cancer patients. Results: Female TYMS-TSER 2R carriers were at increased risk for 5-FU/CAP AEs (odds ratio: 2.195; p = 0.032). 2R/2R genotype was the only factor that increased risk for delayed drug administration or therapy discontinuation (odds ratio: 5.049; p = 0.016). No other associations were found. Conclusion: TYMS-TSER 3R/2R polymorphism was associated with incidence of AEs in female cancer patients. This gender-driven association potentially implicates the ER that, in female patients, potentially regulates TS expression.

Clinical utility of ABCB1 and ABCG2 genotyping for assessing the clinical and pathological response to FAC therapy in Mexican breast cancer patients

PURPOSE

Resistance to neoadjuvant chemotherapy with 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC) in some patients with locally advanced breast cancer remains one of the main obstacles to first-line treatment. We investigated clinical and pathological responses to FAC neoadjuvant chemotherapy in Mexican women with breast cancer and their possible association with SNPs present in ABC transporters as predictors of chemoresistance.

MATERIALS

A total of 102 patients undergoing FAC neoadjuvant chemotherapy were included in the study. SNP analysis was performed by RT-PCR from genomic DNA. Two SNPs were analyzed: ABCB1 rs1045642 (3435 C > T) and ABCG2 rs2231142 (421 G > T).

RESULTS

In clinical response evaluation, significant associations were found between the ABCB1 C3435T genotype and breast cancer chemoresistant and chemosensitive patients (p < 0.05). In the early clinical response, patients with genotype C/C or C/T were more likely to be chemosensitive to neoadjuvant therapy than patients with genotype T/T (OR = 4.055; p = 0.0064). Association analysis between the ABCB1 gene polymorphism and the pathologic response to FAC chemotherapy showed that the C/C + C/T genotype was a protective factor against chemoresistance (OR = 3.714; p = 0.0104). Polymorphisms in ABCG2 indicated a lack of association with resistance to chemotherapy (p = 0.2586) evaluating the clinical or pathological response rate to FAC neoadjuvant chemotherapy.

CONCLUSION

The early clinical response and its association with SNPs in the ABCB1 transporter are preserved until the pathological response to neoadjuvant chemotherapy; therefore, it could be used as a predictor of chemoresistance in locally advanced breast cancer patients of the Mexican population.

ABC transporter superfamily. An updated overview, relevance in cancer multidrug resistance and perspectives with personalized medicine

The ATP binding-cassette superfamily corresponds the mostly transmembrane transporters family found in humans. These proteins actively transport endogenous and exogenous substrates through biological membranes in body tissues, so they have an important role in the regulation of many physiological functions necessary for human homeostasis, as well as in response regulation to several pharmacological substrates. The development of multidrug resistance has become one of the main troubles in conventional chemotherapy in different illnesses including cancer, being the increased efflux of antineoplastic drugs the main reason for this multidrug resistance, with a key role of the ABC superfamily. Likely, the interindividual variability in the pharmacological response among patients is well known, and may be due to intrinsically factors of the disease, genetic and environmental ones. Thus, the understanding of this variability, especially the genetic variability associated with the efficacy and toxicity of drugs, can provide a safer and more effective pharmacological treatment, so ABC genes are considered as important regulators due to their relationship with the reduction in pharmacological response. In this review, updated information about transporters belonging to this superfamily was collected, the possible role of these transporters in cancer, the role of genetic variability in their genes, as well as some therapeutic tools that have been tried to raise against main transporters associated with chemoresistance in cancer.

Cyclophosphamide exposure assessed with the biomarker phosphoramide mustard-hemoglobin in breast cancer patients: The TailorDose I study

Cyclophosphamide (CPA) dosing by body surface area (BSA, m²) has been questioned as a predictor for individual drug exposure. This study investigated phosphoramide mustard-hemoglobin (PAM-Hb, pmol g^-1 Hb) as a biomarker of CPA exposure in 135 female breast cancer patients receiving CPA during three courses based on BSA: 500 mg/m² (C500 group, n = 67) or 600 mg/m² (C600 group, n = 68). The inter-individual difference was calculated for both groups by dividing the highest through the lowest PAM-Hb value of each course. The inter-occasion difference was calculated in percentage for each individual by dividing their PAM-Hb value through the group mean per course, and subsequently dividing this ratio of the latter through the previous course. A multivariable linear regression (MLR) was performed to identify factors that explained the variation of PAM-Hb. During the three courses, the inter-individual difference changed from 3.5 to 2.1 and the inter-occasion difference ranged between 13.3% and 11.9% in the C500 group. In the C600 group, the inter-individual difference changed from 2.7 to 2.9 and the inter-occasion difference ranged between 14.1% and 11.7%. The MLR including BSA, age, GFR, and albumin explained 17.1% of the variation of PAM-Hb and was significantly better then the model including only BSA. These factors should be considered when calculating the first dose of CPA for breast cancer patients.

5-Fluorouracil (5-FU) resistance and the new strategy to enhance the sensitivity against cancer: Implication of DNA repair inhibition

5-Fluorouracil (5-FU) has been an important anti-cancer drug to date. With an increase in the knowledge of its mechanism of action, various treatment modalities have been developed over the past few decades to increase its anti-cancer activity. But drug resistance has greatly affected the clinical use of 5-FU. Overcoming this chemoresistance is a challenge due to the presence of cancer stem cells like cells, cancer recurrence, metastasis, and angiogenesis. In this review, we have systematically discussed the mechanism of 5-FU resistance and advent strategies to increase the sensitivity of 5-FU therapy including resistance reversal. Special emphasis has been given to the cancer stem cells (CSCs) mediated 5-FU chemoresistance and its reversal process by different approaches including the DNA repair inhibition process.

Optimized 5-Fluorouridine Prodrug for Co-Loading with Doxorubicin in Clinically Relevant Liposomes

Liposome-based drug delivery systems have allowed for better drug tolerability and longer circulation times but are often optimized for a single agent due to the inherent difficulty of co-encapsulating two drugs with differing chemical profiles. Here, we design and test a prodrug based on a ribosylated nucleoside form of 5-fluorouracil, 5-fluorouridine (5FUR), with the final purpose of co-encapsulation with doxorubicin (DOX) in liposomes. To improve the loading of 5FUR, we developed two 5FUR prodrugs that involved the conjugation of either one or three moieties of tryptophan (W) known respectively as, 5FUR−W and 5FUR−W₃. 5FUR−W demonstrated greater chemical stability than 5FUR−W3 and allowed for improved loading with fewer possible byproducts from tryptophan hydrolysis. Varied drug ratios of 5FUR−W: DOX were encapsulated for in vivo testing in the highly aggressive 4T1 murine breast cancer model. A liposomal molar ratio of 2.5 5FUR−W: DOX achieved a 62.6% reduction in tumor size compared to the untreated control group and a 33% reduction compared to clinical doxorubicin liposomes in a proof-of-concept study to demonstrate the viability of the co-encapsulated liposomes. We believe that the new prodrug 5FUR−W demonstrates a prodrug design with clinical translatability by reducing the number of byproducts produced by the hydrolysis of tryptophan, while also allowing for loading flexibility.

Clinical and genetic risk factors for the prediction of hepatotoxicity induced by a docetaxel, epirubicin and cyclophosphamide regimen in breast cancer patients

Aim: To screen clinical and genetic risk factors and examine their combined effect on docetaxel, epirubicin and cyclophosphamide (TEC) regimen-induced liver injury (TEC-ILI). Patients & methods: We enrolled 396 breast cancer patients, and TEC-ILI-associated factors were screened by logistic regression analyses. Results: SOD2 rs4880 and ABCG2 rs2231142 polymorphisms correlated with an increased risk of TEC-ILI. Multivariate analysis incorporating clinical and genetic factors revealed that ABCC1 rs246221 (CC) and SOD2 rs4880 (AG/GG) increased the risk of TEC-ILI. Patients with at least two risk factors among nonalcoholic fatty liver disease, high low-density lipoproteinemia levels and the rs246221 or rs4880 adverse genotypes exhibited a significantly increased risk of developing TEC-ILI. Conclusion: The combination of clinical and genetic risk factors had higher predictive value for TEC-ILI than the interclinical risk factors alone.

Organic Cation Transporters in Human Physiology, Pharmacology, and Toxicology

Individual cells and epithelia control the chemical exchange with the surrounding environment by the fine-tuned expression, localization, and function of an array of transmembrane proteins that dictate the selective permeability of the lipid bilayer to small molecules, as actual gatekeepers to the interface with the extracellular space. Among the variety of channels, transporters, and pumps that localize to cell membrane, organic cation transporters (OCTs) are considered to be extremely relevant in the transport across the plasma membrane of the majority of the endogenous substances and drugs that are positively charged near or at physiological pH. In humans, the following six organic cation transporters have been characterized in regards to their respective substrates, all belonging to the solute carrier 22 (SLC22) family: the organic cation transporters 1, 2, and 3 (OCT1–3); the organic cation/carnitine transporter novel 1 and 2 (OCTN1 and N2); and the organic cation transporter 6 (OCT6). OCTs are highly expressed on the plasma membrane of polarized epithelia, thus, playing a key role in intestinal absorption and renal reabsorption of nutrients (e.g., choline and carnitine), in the elimination of waste products (e.g., trimethylamine and trimethylamine N-oxide), and in the kinetic profile and therapeutic index of several drugs (e.g., metformin and platinum derivatives). As part of the Special Issue Physiology, Biochemistry, and Pharmacology of Transporters for Organic Cations, this article critically presents the physio-pathological, pharmacological, and toxicological roles of OCTs in the tissues in which they are primarily expressed.

Amelioration of cyclophosphamide-induced myelosuppression during treatment to rats with breast cancer through low-intensity pulsed ultrasound

To investigate the alleviating effects of low-intensity pulsed ultrasound (LIPUS) on myelosuppression of Sprague–Dawley rats with breast cancer induced by cyclophosphamide (CTX). Breast cancer in rats was triggered by intragastric gavage with 7,12-dimethylbenz[a]anthracene (150 mg/kg). Then, the rats with breast cancer were randomly allocated to the LIPUS group (n=50) and the control group (n=50). The LIPUS group was injected intraperitoneally with CTX (50 mg/kg) for 4 consecutive days and underwent LIPUS treatment at femoral metaphysis 20 min per day from the first day of injection for 7 consecutive days. The control group was injected with CTX (50 mg/kg) and treated with LIPUS without energy output. Blood, enzyme-linked immunosorbent assay (ELISA), real-time quantitative polymerase chain reaction, Hematoxylin and Eosin (H&E) staining, and scanning electron microscopy were applied to detect the changes. The results indicated that LIPUS significantly promoted the proliferation of bone marrow nucleated cells, white blood cells (WBCs), IgA, IgG, and IgM in the peripheral blood (P<0.05) without the damage to liver and kidney function simultaneously. The mechanisms may result from the LIPUS alleviation effect on bone marrow hematopoietic function through regulating cytokines such as LIPUS can increase the expression of granulocyte colony-stimulating factor (G-CSF), stem cell factor, transforming growth factor-β, and intercellular cell adhesion molecule-1, meanwhile LIPUS will decrease the expression of interleukin-6, tumor necrosis factor-α, and vascular cell adhesion molecule-1. LIPUS has potential to be a new adjuvant therapy method in clinic for ameliorating chemotherapy-induced myelosuppression.

Dual TTK/CLK2 inhibitor, CC-671, selectively antagonizes ABCG2-mediated multidrug resistance in lung cancer cells

One pivotal factor that leads to multidrug resistance (MDR) is the overexpression of ABCG2. Therefore, tremendous effort has been devoted to the search of effective reversal agents to overcome ABCG2‐mediated MDR. CC‐671 is a potent and selective inhibitor of both TTK (human protein kinase monopolar spindle 1 [hMps1]) and CDC like kinase 2 (CLK2). It represents a new class of cancer therapeutic drugs. In this study, we show that CC‐671 is an effective ABCG2 reversal agent that enhances the efficacy of chemotherapeutic drugs in ABCG2‐overexpressing lung cancer cells. Mechanistic studies show that the reversal effect of CC‐671 is primarily attributed to the inhibition of the drug efflux activity of ABCG2, which leads to an increased intracellular level of chemotherapeutic drugs. In addition, CC‐671 does not alter the protein expression or subcellular localization of ABCG2. The computational molecule docking analysis suggests CC‐671 has high binding affinity to the drug‐binding site of ABCG2. In conclusion, we reveal the interaction between CC‐671 and ABCG2, providing a rationale for the potential combined use of CC‐671 with ABCG2 substrate to overcome MDR.

Genetic 3'UTR variations and clinical factors significantly contribute to survival prediction and clinical response in breast cancer patients

The study describes a relationship between the 3′UTR variants, clinicopathological parameters and response to chemotherapy. We analyzed 33 germline polymorphisms in 3′UTRs of ADME genes in 305 breast cancer women treated with FAC regime. Clinical endpoints of this study were: overall survival (OS), progression-free survival (PFS), recurrence-free survival (RFS) and overall response defined as treatment failure-free survival (TFFS). The shortened OS was connected with the presence of NR1/2 rs3732359 AA, SLC22A16 rs7756222 CC, as well as SLC22A16 rs9487402 allele G and clinical factors belonging to TNM classification: tumor size >1 cm, nodal involvement and presence of metastases. PFS was related to two polymorphisms PGR rs1824125 GG, PGR rs12224560 CC and SLC22A16 rs7756222 CC as well as preexisting metastases. The RFS was shortened due to the DPYD rs291593 CC, AKR1C3 rs3209896 AG and negative expression of PGR. The presence of ALDH5A1 rs1054899 allele A, lack of pre-chemotherapy surgery and negative status of PGR correlated with worse treatment response. The germline variants commonly present in the population are important factors determining the response to treatment. We observed the effect of the accumulation of genetic and clinical factors on poor survival prognosis and overall treatment response.

IMMUNEPOTENT CRP plus doxorubicin/cyclophosphamide chemotherapy remodel the tumor microenvironment in an air pouch triple-negative breast cancer murine model

In 1889, Steven Paget postulated the theory that cancer cells require a permissive environment to grow. This permissive environment is known as the tumor microenvironment (TME) and nowadays it is evident that the TME is involved in the progression and response to therapy of solid cancer tumors. Triple-negative breast cancer is one of the most lethal types of cancer for women worldwide and chemotherapy remains the standard treatment for these patients. IMMUNEPOTENT CRP is a bovine dialyzable leukocyte extract with immunomodulatory and antitumor properties. The combination of chemotherapy and IMMUNEPOTENT CRP improves clinical parameters of breast cancer patients. In the current study, we aimed to evaluate the antitumor effect of doxorubicin/cyclophosphamide chemotherapy plus IMMUNEPOTENT CRP and its impact over the tumor microenvironment in a triple-negative breast cancer murine model. We evaluated CD8⁺, CD4⁺, T regulatory cells, memory T cells, myeloid-derived suppressor cells, CD71⁺, innate effector cells and molecules such as α-SMA, VEGF, CTLA-4, PD-L1, Gal-3, IDO, IL-2, IFN-γ, IL-12, IL-6, MCP-1, and IL-10 as part of the components of the TME. Doxorubicin/cyclophosphamide + IMMUNEPOTENT CRP decreased tumor volume, prolonged survival, increased infiltrating and systemic CD8⁺ T cells and decreased tumor suppressor molecules (such as PD-L1, Gal-3, and IL-10 among others). In conclusion, we suggest that IMMUNEPOTENT CRP act as a modifier of the TME and the immune response, potentiating or prolonging anti-tumor effects of doxorubicin/cyclophosphamide in a triple-negative breast cancer murine model.

Sterically Stabilised Polymeric Mesoporous Silica Nanoparticles Improve Doxorubicin Efficiency: Tailored Cancer Therapy

The fruition, commercialisation and clinical application combining nano-engineering, nanomedicine and material science for utilisation in drug delivery is becoming a reality. The successful integration of nanomaterial in nanotherapeutics requires their critical development to ensure physiological and biological compatibility. Mesoporous silica nanoparticles (MSNs) are attractive nanocarriers due to their biodegradable, biocompatible, and relative malleable porous frameworks that can be functionalized for enhanced targeting and delivery in a variety of disease models. The optimal formulation of an MSN with polyethylene glycol (2% and 5%) and chitosan was undertaken, to produce sterically stabilized, hydrophilic MSNs, capable of efficient loading and delivery of the hydrophobic anti-neoplastic drug, doxorubicin (DOX). The pH-sensitive release kinetics of DOX, together with the anticancer, apoptosis and cell-cycle activities of DOX-loaded MSNs in selected cancer cell lines were evaluated. MSNs of 36-60 nm in size, with a pore diameter of 9.8 nm, and a cumulative surface area of 710.36 m²/g were produced. The 2% pegylated MSN formulation (PCMSN) had the highest DOX loading capacity (0.98 mgdox/mgmsn), and a sustained release profile over 72 h. Pegylated-drug nanoconjugates were effective at a concentration range between 20-50 μg/mL, inducing apoptosis in cancer cells, and affirming their potential as effective drug delivery vehicles.

Mitigating Effect of 1-Palmitoyl-2-Linoleoyl-3-Acetyl-Rac-Glycerol (PLAG) on a Murine Model of 5-Fluorouracil-Induced Hematological Toxicity

5-Fluorouracil (5-FU) is an antimetabolite chemotherapy widely used for the treatment of various cancers. However, many cancer patients experience hematological side effects following 5-FU treatment. Here, we investigated the protective effects of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) as a mitigator against 5-FU-induced hematologic toxicity, including neutropenia, monocytopenia, thrombocytopenia, and thrombocytosis, in Balb/c mice injected with 5-FU (100 mg/kg, i.p.). Administration of PLAG significantly and dose-dependently reduced the duration of neutropenia and improved the nadirs of absolute neutrophil counts (ANCs). Moreover, while the ANCs of all mice in the control fell to the severely neutropenic range, none of the mice in the PLAG 200 and 400 mg/kg-treated groups experienced severe neutropenia. Administration of PLAG significantly delayed the mean first day of monocytopenia and reduced the duration of monocytopenia. PLAG also effectively reduced extreme changes in platelet counts induced by 5-FU treatment, thus preventing 5-FU-induced thrombocytopenia and thrombocytosis. PLAG significantly decreased plasma levels of the chemokine (C–X–C motif) ligand 1 (CXCL1), CXCL2, interleukin (IL)-6, and C-reactive protein (CRP), which were elevated consistently with the occurrence time of neutropenia, monocytopenia, and thrombocytopenia. When compared with olive oil and palmitic linoleic hydroxyl glycerol (PLH), only PLAG effectively mitigated 5-FU-induced hematological toxicity, indicating that it has a distinctive mechanism of action. In conclusion, PLAG may have therapeutic potential as a mitigator for 5-FU-induced neutropenia and other hematological disorders.

The genetic landscape of the human solute carrier (SLC) transporter superfamily

The human solute carrier (SLC) superfamily of transporters is comprised of over 400 membrane-bound proteins, and plays essential roles in a multitude of physiological and pharmacological processes. In addition, perturbation of SLC transporter function underlies numerous human diseases, which renders SLC transporters attractive drug targets. Common genetic polymorphisms in SLC genes have been associated with inter-individual differences in drug efficacy and toxicity. However, despite their tremendous clinical relevance, epidemiological data of these variants are mostly derived from heterogeneous cohorts of small sample size and the genetic SLC landscape beyond these common variants has not been comprehensively assessed. In this study, we analyzed Next-Generation Sequencing data from 141,456 individuals from seven major human populations to evaluate genetic variability, its functional consequences, and ethnogeographic patterns across the entire SLC superfamily of transporters. Importantly, of the 204,287 exonic single-nucleotide variants (SNVs) which we identified, 99.8% were present in less than 1% of analyzed alleles. Comprehensive computational analyses using 13 partially orthogonal algorithms that predict the functional impact of genetic variations based on sequence information, evolutionary conservation, structural considerations, and functional genomics data revealed that each individual genome harbors 29.7 variants with putative functional effects, of which rare variants account for 18%. Inter-ethnic variability was found to be extensive, and 83% of deleterious SLC variants were only identified in a single population. Interestingly, population-specific carrier frequencies of loss-of-function variants in SLC genes associated with recessive Mendelian disease recapitulated the ethnogeographic variation of the corresponding disorders, including cystinuria in Jewish individuals, type II citrullinemia in East Asians, and lysinuric protein intolerance in Finns, thus providing a powerful resource for clinical geneticists to inform about population-specific prevalence and allelic composition of Mendelian SLC diseases. In summary, we present the most comprehensive data set of SLC variability published to date, which can provide insights into inter-individual differences in SLC transporter function and guide the optimization of population-specific genotyping strategies in the bourgeoning fields of personalized medicine and precision public health.

A yeast phenomic model for the influence of Warburg metabolism on genetic buffering of doxorubicin

BACKGROUND

The influence of the Warburg phenomenon on chemotherapy response is unknown. Saccharomyces cerevisiae mimics the Warburg effect, repressing respiration in the presence of adequate glucose. Yeast phenomic experiments were conducted to assess potential influences of Warburg metabolism on gene-drug interaction underlying the cellular response to doxorubicin. Homologous genes from yeast phenomic and cancer pharmacogenomics data were analyzed to infer evolutionary conservation of gene-drug interaction and predict therapeutic relevance.

METHODS

Cell proliferation phenotypes (CPPs) of the yeast gene knockout/knockdown library were measured by quantitative high-throughput cell array phenotyping (Q-HTCP), treating with escalating doxorubicin concentrations under conditions of respiratory or glycolytic metabolism. Doxorubicin-gene interaction was quantified by departure of CPPs observed for the doxorubicin-treated mutant strain from that expected based on an interaction model. Recursive expectation-maximization clustering (REMc) and Gene Ontology (GO)-based analyses of interactions identified functional biological modules that differentially buffer or promote doxorubicin cytotoxicity with respect to Warburg metabolism. Yeast phenomic and cancer pharmacogenomics data were integrated to predict differential gene expression causally influencing doxorubicin anti-tumor efficacy.

RESULTS

Yeast compromised for genes functioning in chromatin organization, and several other cellular processes are more resistant to doxorubicin under glycolytic conditions. Thus, the Warburg transition appears to alleviate requirements for cellular functions that buffer doxorubicin cytotoxicity in a respiratory context. We analyzed human homologs of yeast genes exhibiting gene-doxorubicin interaction in cancer pharmacogenomics data to predict causality for differential gene expression associated with doxorubicin cytotoxicity in cancer cells. This analysis suggested conserved cellular responses to doxorubicin due to influences of homologous recombination, sphingolipid homeostasis, telomere tethering at nuclear periphery, actin cortical patch localization, and other gene functions.

CONCLUSIONS

Warburg status alters the genetic network required for yeast to buffer doxorubicin toxicity. Integration of yeast phenomic and cancer pharmacogenomics data suggests evolutionary conservation of gene-drug interaction networks and provides a new experimental approach to model their influence on chemotherapy response. Thus, yeast phenomic models could aid the development of precision oncology algorithms to predict efficacious cytotoxic drugs for cancer, based on genetic and metabolic profiles of individual tumors.

Cost-minimization analysis of GSTP1c.313A>G genotyping for the prevention of cisplatin-induced nausea and vomiting: A Bayesian inference approach

Background

Chemotherapy-induced nausea and vomiting are concerning adverse events resulting from cancer treatment, and current guidelines recommend the use of neurokinin-1-selective antagonists, such as fosaprepitant, in highly emetogenic schemes. However, the implementation of this strategy may be limited by the cost of treatment. GSTP1 c.313A>G genotype was recently described as a predictor of vomiting related to high-dose cisplatin. We hypothesized that the inclusion of routine GSTP1 c.313A>G screening may be promising in financial terms, in contrast to the wide-spread use of fosaprepitant.

Methods

A cost-minimization analysis was planned to compare GSTP1 c.313A>G genotyping versus overall fosaprepitant implementation for patients with head and neck cancer under chemoradiation therapy with high-dose cisplatin. A decision analytic tree was designed, and conditional probabilities were calculated under Markov chain Monte Carlo simulations using the Metropolis-Hastings algorithm. The observed data included patients under treatment without fosaprepitant, while priors were derived from published studies.

Results

To introduce screening with real-time polymerase chain reaction, an initial investment of U$ 39,379.97 would be required, with an amortization cost of U$ 7,272.97 per year. The mean cost of standard therapy with fosaprepitant is U$ 243.24 per patient, and although the initial cost of routine genotyping is higher, there is a tendency of progressive minimization at a threshold of 155 patients (Credible interval–CI: 119 to 216), provided more than one sample is incorporated for simultaneous analysis. A resulting reduction of 35.83% (CI: 30.31 to 41.74%) in fosaprepitant expenditures is then expected with the implementation of GSTP1 c.313A>G genotyping.

Conclusion

GSTP1 c.313A>G genotyping may reduce the use of preventive support for chemotherapy induced nausea and lower the overall cost of treatment. Despite the results of this simulation, randomized, interventional studies are required to control for known and unknown confounders as well as unexpected expenses.

Factors Influencing Quality of Life in Breast Cancer Patients Six Months after the Completion of Chemotherapy

Purpose: To assess breast cancer patients’ quality of life six months after the completion of adjuvant chemotherapy, and to investigate factors affecting this. Methods: The study was conducted in one large hospital located in a major Greek city. A convenience sample of 61 breast cancer outpatients was recruited. A questionnaire, including the SF-36 scale and questions regarding demographic and clinical information, was used to collect data. Results: The mean age of the patients was 51.52 ± 12.10. The effect of age on the physical role was significant (p = 0.003). Τhe effect of menopausal status on physical role was also found to be significant (p = 0.003); this might be explained by age. Regarding the treatment type, patients who received hormone therapy in addition to surgery and chemotherapy reported a significantly higher quality of life in terms of bodily pain (p = 0.04) and vitality (p = 0.04) than patients who underwent only surgery and chemotherapy. Conclusions: Quality of life is affected by factors such as age, menopausal status, and previous therapy. Health care professionals should be more aware of the factors that influence the quality of life domains (physical role, bodily pain, vitality) within this group of cancer patients in order to meet their needs following acute treatment.

OCTN: A Small Transporter Subfamily with Great Relevance to Human Pathophysiology, Drug Discovery, and Diagnostics

OCTN is a small subfamily of membrane transport proteins that belongs to the larger SLC22 family. Two of the three members of the subfamily, namely, OCTN2 and OCTN1, are present in humans. OCTN2 plays a crucial role in the absorption of carnitine from diet and in its distribution to tissues, as demonstrated by the occurrence of severe pathologies caused by malfunctioning or altered expression of this transporter. These findings suggest avoiding a strict vegetarian diet during pregnancy and in childhood. Other roles of OCTN2 are related to the traffic of carnitine derivatives in many tissues. The role of OCTN1 is still unclear, despite the identification of some substrates such as ergothioneine, acetylcholine, and choline. Plausibly, the transporter acts on the control of inflammation and oxidative stress, even though knockout mice do not display phenotypes. A clear role of both transporters has been revealed in drug interaction and delivery. The polyspecificity of the OCTNs is at the base of the interactions with drugs. Interestingly, OCTN2 has been recently exploited in the prodrug approach and in diagnostics. A promising application derives from the localization of OCTN2 in exosomes that represent a noninvasive diagnostic tool.