Sex and Gender Differences in Anticancer Treatment Toxicity: A Call for Revisiting Drug Dosing in Oncology

Population Pharmacokinetics of Trametinib and Impact of Nonadherence on Drug Exposure in Oncology Patients as Part of the Optimizing Oral Targeted Anticancer Therapies Study

Trametinib is a targeted therapy used for the treatment of solid tumours, with significant variability reported in real-life studies. This variability increases the risk of suboptimal exposure, which can lead to treatment failure or increased toxicity. Using model-based simulation, this study aims to characterize and investigate the pharmacokinetics and the adequacy of the currently recommended doses of trametinib. Additionally, the simulation of various suboptimal adherence scenarios allowed for an assessment of the impact of patients' drug adherence on the treatment outcome. The population data collected in 33 adult patients, providing 113 plasmatic trametinib concentrations, were best described by a two-compartment model with linear absorption and elimination. The study also identified a significant positive effect of fat-free mass and a negative effect of age on clearance, explaining 66% and 21% of the initial associated variability, respectively. Simulations showed that a maximum dose of 2 mg daily achieved the therapeutic target in 36% of male patients compared to 72% of female patients. A dose of 1.5 mg per day in patients over 65 years of age achieved similar rates, with 44% and 79% for male and female patients, respectively, reaching the therapeutic target. Poor adherence leads to a significant drop in concentrations and a high risk of subtherapeutic drug levels. These results underline the importance of interprofessional collaboration and patient partnership along the patient's journey to address patients' needs regarding trametinib and support medication adherence.

Maximum tolerated dose and toxicity evaluation of orally administered docetaxel granule in mice

Oral delivery of chemotherapy drugs is the most favorable and preferred route of drug administration. However, because of poor solubility and/or permeability, most chemotherapy drugs are given by intravenous administration. Docetaxel (DTX) is a potent chemotherapy drug that inhibits microtubular depolymerization and is widely used to treat numerous cancers. DTX is highly lipophilic and insoluble in water; thus, 50% polysorbate 80, which may cause hypersensitivity reactions and reduce drug uptake by tumor tissue, is used in the commercial DTX injection to dissolve DTX. Maximum tolerated dose (MTD) and toxicity are important to determine parameters in preclinical studies and to predict human dose in clinical trials. However, MTD and toxicity of oral DTX formulations have not been studied although various oral DTX formulations have been reported. We have previously developed oral DTX granule and demonstrated its ability to inhibit tumor growth. In this study, we aimed to systemically measure MTD and tissue distribution and evaluate the toxicity of oral DTX granule in mice. Oral DTX granule showed sex differences in toxicity and absorption. The MTD of DTX granule was determined at 50 mg/kg for female mice and 25 mg/kg for male mice. However, female mice had higher tissue absorption than male mice. At a very high dose (400 mg/kg), oral DTX granule induced kidney damage but did not influence the liver and the lungs. The study provides the fundamental data for future preclinical studies and clinical application of oral DTX formulations for cancers.

Gender differences in adverse events related to Osimertinib: a real-world pharmacovigilance analysis of FDA adverse event reporting system

OBJECTIVE

We analyze and identify the signals of gender differences in adverse events (ADEs) related to Osimertinib and provide reference for clinical implementation of individualized drug use.

METHODS

ADE reports of Osimertinib received from FAERS database from the first quarter of 2016 to the fourth quarter of 2022 were extracted. Reporting odds ratio (ROR) data analysis strategy was used for mining of signal strength that represents gender differences in ADEs related to Osimertinib.

RESULTS

The number of Osimertinib ADE reports included in the analysis was 7968 in females and 7570 in males, respectively. According to ROR, men were more likely to develop pneumonia aspiration, lung infection, interstitial lung disease, pulmonary toxicity, dyspnea, ventricular extrasystoles, and pulmonary thrombosis, while women were more likely to develop cardiac failure congestive, stomatitis, diarrhea, muscle spasms, nail disorder, onycholysis, skin disorder, dry skin, and rash.

CONCLUSION

Gender differences existed in ADE signals related to Osimertinib. The higher risk of ADEs in male patients was lung diseases that seem more serious than those nail toxicities or skin problems that occurred in female patients. In order to ensure the safety of medication, we should be alert to the differences between different genders and take corresponding preventive measures to reduce the occurrence of serious ADEs.

Hand-foot syndrome in cancer patients on capecitabine: examining prevalence, impacts, and associated risk factors at a cancer centre in Malaysia

INTRODUCTION

Hand-foot syndrome (HFS) significantly impacts quality of life in cancer patients undergoing capecitabine treatment. This study assessed capecitabine-associated HFS prevalence, its impacts on chemotherapy treatment, and identified risk factors in multiracial Malaysian patients.

METHODS

We included adult cancer patients receiving capecitabine at Sarawak General Hospital for at least two cycles from April 1, 2021 to June 30, 2022. HFS rates, time to HFS, and proportions of HFS-related treatment modifications were determined. Characteristics between patients with and without HFS were compared and multivariable logistic regression was used to identify risk factors for all-grade HFS and grade ≥2.

RESULTS

Among 369 patients, 185 (50.1%) developed HFS, with 14.6% experiencing grade ≥2 and 21.6% (40/185) underwent treatment modifications. Risk factors for all-grade HFS include older age (OR 1.03 95%CI 1.01, 1.06), prior chemotherapy (OR 2.09 95%CI 1.22, 3.58), higher capecitabine dose (OR 2.96 95%CI 1.62, 5.38), prolonged treatment (OR 1.36 95%CI 1.21, 1.51), folic acid intake (OR 3.27 95%CI 1.45, 7.35) and lower neutrophil count (OR 0.77 95%CI 0.66, 0.89). For HFS grade ≥2, older age (OR 1.04 95%CI 1.01, 1.08), female sex (OR 2.10 95%CI 1.05, 4.18), Chinese race (OR 2.10 95%CI 1.06, 4.18), and higher capecitabine dose (OR 2.62 95%CI 1.28, 5.35) are significant risk factors. Use of calcium channel blockers were associated with reduced risks of all-grade HFS (OR 0.27, 95%CI 0.12, 0.60) and grade ≥2 (OR 0.21 95%CI 0.06, 0.78).

CONCLUSION

This study provides real-world data on capecitabine-induced HFS in Malaysian patients and identifies risk factors that may offer insights into its understanding and management.

Hallmarks of sex bias in immuno-oncology: mechanisms and therapeutic implications

Sex differences are present across multiple non-reproductive organ cancers, with male individuals generally experiencing higher incidence of cancer with poorer outcomes. Although some mechanisms underlying these differences are emerging, the immunological basis is not well understood. Observations from clinical trials also suggest a sex bias in conventional immunotherapies with male individuals experiencing a more favourable response and female individuals experiencing more severe adverse events to immune checkpoint blockade. In this Perspective article, we summarize the major biological hallmarks underlying sex bias in immuno-oncology. We focus on signalling from sex hormones and chromosome-encoded gene products, along with sex hormone-independent and chromosome-independent epigenetic mechanisms in tumour and immune cells such as myeloid cells and T cells. Finally, we highlight opportunities for future studies on sex differences that integrate sex hormones and chromosomes and other emerging cancer hallmarks such as ageing and the microbiome to provide a more comprehensive view of how sex differences underlie the response in cancer that can be leveraged for more effective immuno-oncology approaches.

Hourglass, a compass navigating global and regional heterogeneity of pancreatic cancer†

Advances in the digital pathology field have facilitated the characterization of histology samples for both clinical and preclinical research. However, uncovering subtle correlations between bioimaging, clinical and molecular parameters requires extensive statistical analysis. As a user-friendly software, Hourglass, simplifies multiparametric dataset analysis through intuitive data visualization and statistical tools. Systemic analysis of interleukin-6 (IL-6)/pStat3 signaling pathway through Hourglass revealed differences in regional immune cell composition within tumors. Moreover, these regional disparities were partially mediated by sex. Overall, Hourglass simplifies information extraction from complex datasets, resolving overlooked regional and global spatial tumor differences. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

DFMO inhibition of neuroblastoma tumorigenesis

BACKGROUND

Most high-risk neuroblastoma patients who relapse succumb to disease despite the existing therapy. We recently reported increased event-free and overall survival in neuroblastoma patients receiving difluoromethylornithine (DFMO) during maintenance therapy. The effect of DFMO on cellular processes associated with neuroblastoma tumorigenesis needs further elucidation. Previous studies have shown cytotoxicity with IC50 values >5-15 mM, these doses are physiologically unattainable in patients, prompting further mechanistic studies at therapeutic doses.

METHODS

We characterized the effect of DFMO on cell viability, cell cycle, apoptosis, neurosphere formation, and protein expression in vitro using five established neuroblastoma cell lines (BE2C, CHLA-90, SHSY5Y, SMS-KCNR, and NGP) at clinically relevant doses of 0, 50, 100, 500, 1000, and 2500 μM. Limiting Dilution studies of tumor formation in murine models were performed. Statistical analysis was done using GraphPad and the level of significance set at p = 0.05.

RESULTS

There was not a significant loss of cell viability or gain of apoptotic activity in the in vitro assays (p > 0.05). DFMO treatment initiated G1 to S phase cell cycle arrest. There was a dose-dependent decrease in frequency and size of neurospheres and a dose-dependent increase in beta-galactosidase activity in all cell lines. Tumor formation was decreased in xenografts both with DFMO-pretreated cells and in mice treated with DFMO.

CONCLUSION

DFMO treatment is cytostatic at physiologically relevant doses and inhibits tumor initiation and progression in mice. This study suggests that DFMO, inhibits neuroblastoma by targeting cellular processes integral to neuroblastoma tumorigenesis at clinically relevant doses.

A case for seeking sex-specific treatments in Alzheimer's disease

There is no satisfactory explanation for the sex-related differences in the incidence of many diseases and this is also true of Alzheimer's disease (AD), where females have a higher lifetime risk of developing the disease and make up about two thirds of the AD patient population. The importance of understanding the cause(s) that account for this disproportionate distribution cannot be overestimated, and is likely to be a significant factor in the search for therapeutic strategies that will combat the disease and, furthermore, potentially point to a sex-targeted approach to treatment. This review considers the literature in the context of what is known about the impact of sex on processes targeted by drugs that are in clinical trial for AD, and existing knowledge on differing responses of males and females to these drugs. Current knowledge strongly supports the view that trials should make assessing sex-related difference in responses a priority with a focus on exploring the sex-stratified treatments.

Awareness of the impact of sex and gender in the disease risk and outcomes in hematology and medical oncology-a survey of Swiss clinicians

BACKGROUND

Although male and female cancer patients are distinct in many ways, there is a limited understanding in the differences between male and female biology and differing pharmacokinetic responses to cancer drugs. In fact, sex and gender are currently not considered in most treatment decisions in the fields of oncology and hematology. The lack of knowledge about potential sex differences in both disciplines may lead to differences in treatment efficacy, toxicity, and the overall survival (OS) of patients.

AIM

To evaluate their awareness about sex and gender in clinical practice we surveyed Swiss hematologists and oncologists from September to November 2022.

METHODS

We collected data about the clinical knowledge, experimental research, palliative care, quality of life, as well as the participant perception of the importance of sex and gender. We identified 767 eligible clinicians, of whom 150 completed the survey (20% response rate).

RESULTS

While most participants agreed that sex and gender were relevant when treating patients, it became clear that fewer participants knew about sex and gender differences in treatment toxicity and survival, which in turn would affect the treatment of their patients. Most participants agreed that this topic should be integrated into continuing education and research.

CONCLUSION

Our findings indicate the need for more awareness and training on sex and gender in cancer research and clinical care among oncologists and hematologists. Ideally, by better educating medical students and health professionals, a demand is created for improving research policies, publications and therefore patient care.

Sex-specific molecular differences in glioblastoma: assessing the clinical significance of genetic variants

Introduction

Glioblastoma multiforme (GBM) is one of the most aggressive types of brain cancer, and despite rigorous research, patient prognosis remains poor. The characterization of sex-specific differences in incidence and overall survival (OS) of these patients has led to an investigation of the molecular mechanisms that may underlie this dimorphism.

Methods

We reviewed the published literature describing the gender specific differences in GBM Biology reported in the last ten years and summarized the available information that may point towards a patient-tailored GBM therapy.

Results

Radiomics analyses have revealed that imaging parameters predict OS and treatment response of GBM patients in a sex-specific manner. Moreover, gender-based analysis of the transcriptome GBM tumors has found differential expression of various genes, potentially impacting the OS survival of patients in a sex-dependent manner. In addition to gene expression differences, the timing (subclonal or clonal) of the acquisition of common GBM-driver mutations, metabolism requirements, and immune landscape of these tumors has also been shown to be sex-specific, leading to a differential therapeutic response by sex. In male patients, transformed astrocytes are more sensitive to glutaminase 1 (GLS1) inhibition due to increased requirements for glutamine uptake. In female patients, GBM is more sensitive to anti-IL1β due to an increased population of circulating granulocytic myeloid-derived suppressor cells (gMDSC).

Conclusion

Moving forward, continued elucidation of GBM sexual dimorphism will be critical in improving the OS of GBM patients by ensuring that treatment plans are structured to exploit these sex-specific, molecular vulnerabilities in GBM tumors.

Why and How to Account for Sex and Gender in Brain and Behavioral Research

Long overlooked in neuroscience research, sex and gender are increasingly included as key variables potentially impacting all levels of neurobehavioral analysis. Still, many neuroscientists do not understand the difference between the terms "sex" and "gender," the complexity and nuance of each, or how to best include them as variables in research designs. This TechSights article outlines rationales for considering the influence of sex and gender across taxa, and provides technical guidance for strengthening the rigor and reproducibility of such analyses. This guidance includes the use of appropriate statistical methods for comparing groups as well as controls for key covariates of sex (e.g., total intracranial volume) and gender (e.g., income, caregiver stress, bias). We also recommend approaches for interpreting and communicating sex- and gender-related findings about the brain, which have often been misconstrued by neuroscientists and the lay public alike.

Foot health and quality of life in women with breast cancer undergoing chemotherapy: a cross-sectional study

BACKGROUND

Chemotherapy is one of the most widely used therapies for breast cancer, triggering important repercussions on people's quality of life. However, little research has been undertaken about podiatric adverse effects. This study aimed was to determine the prevalence of podiatric pathology developed in people with breast cancer who receive chemotherapy.

METHODS

Observational, descriptive, and cross-sectional study was conducted in the Oncology service of the A Coruña University Hospital (northwest Spain). People with breast cancer and undergoing chemotherapy treatment of legal age (≥ 18), who signed the informed consent (n = 117) were included. Sociodemographic, comorbidity, disease and foot health variables, as well as two self-administered questionnaires (Foot Health Status Questionnaire and Foot Function Index) were studied. The current ethical-legal aspects were followed.

RESULTS

Foot health problems were highly prevalent, highlighting nail color changes (59.8%), onychocryptosis (39.7%), xerosis (62.4%), plantar fasciitis (12.8%), and neuropathic symptoms (75.2%). Some foot pain was presented in 77.8% of the sample, predominantly at nail level (15.4%) or sole of the foot and nail (14.5%). Most participants described their foot health as fair or poor (56.4%) and felt limited in walking (65.8%). The lowest score for the Foot Health Status Questionnaire was footwear (30.6(33.5)).

CONCLUSIONS

Foot health adverse effects represent worrisome problems in women with breast cancer undergoing chemotherapy, due to their high prevalence and negative implications on quality of life. These problems are critical as they may have implications for stopping or reducing chemotherapy. All these results call for the development of more research to contribute to the care and wellbeing of people with cancer who receive treatments such as chemotherapy. Thus, this line of research is a new path to be developed by the podiatry community.

Impact of sex on the efficacy and safety of panitumumab plus fluorouracil and folinic acid versus fluorouracil and folinic acid alone as maintenance therapy in RAS WT metastatic colorectal cancer (mCRC). Subgroup analysis of the PanaMa-study (AIO-KRK-0212)

BACKGROUND

Clinical trials in metastatic colorectal cancer (mCRC) are usually conducted irrespective of sex. Sex-associated differences relating to safety and efficacy in the treatment of mCRC, however, are gaining interest.

METHODS

PanaMa investigated the efficacy of panitumumab (Pmab) plus fluorouracil and folinic acid (FU/FA) versus FU/FA alone after induction therapy with six cycles of FU/FA and oxaliplatin plus Pmab in patients with RAS wild-type mCRC. In this post hoc analysis, the study population was stratified for sex. Evaluated efficacy endpoints during maintenance treatment were progression-free survival (PFS, primary endpoint of the trial), overall survival (OS) and objective response rate during maintenance therapy. Safety endpoints were rates of any grade and grade 3/4 adverse events during maintenance therapy.

RESULTS

In total, 165 male and 83 female patients were randomized and treated. Male and female patients showed numerically better objective response rates with Pmab, without reaching statistical significance. Male patients derived a significant benefit from the addition of Pmab to maintenance treatment with regard to PFS [hazard ratio (HR) 0.63; 95% confidence interval (CI) 0.45-0.88; P = 0.006] that was not observed in female patients (HR 0.85; 95% CI 0.53-1.35; P = 0.491). The better PFS for male patients treated with Pmab did not translate into improved OS (HR 0.85; 95% CI 0.55-1.30; P = 0.452). Female patients showed numerically improved OS when treated with Pmab. There was no difference in the total of grade ≥3 adverse events during maintenance regarding sex (P = 0.791). Female patients, however, had a higher rate of any grade nausea, diarrhea and stomatitis.

CONCLUSIONS

In the PanaMa trial, the addition of Pmab to maintenance treatment of RAS wild-type mCRC with FU/FA improved the outcome in terms of the primary endpoint (PFS) particularly in male patients. Female patients did not show the same benefit while experiencing higher rates of adverse events. Our results support the development of sex-specific protocols.

Understanding circadian dynamics: current progress and future directions for chronobiology in drug discovery

INTRODUCTION

Most mammalian physiology is orchestrated by the circadian clock, including drug transport and metabolism. As a result, efficacy and toxicity of many drugs are influenced by the timing of their administration, which has led to the establishment of the field of chronopharmacology.

AREAS COVERED

In this review, the authors provide an overview of the current knowledge about the time-of-day dependent aspects of drug metabolism and the importance of chronopharmacological strategies for drug development. They also discuss the factors influencing rhythmic drug pharmacokinetic including sex, metabolic diseases, feeding rhythms, and microbiota, that are often overlooked in the context of chronopharmacology. This article summarizes the involved molecular mechanisms and functions and explains why these parameters should be considered in the process of drug discovery.

EXPERT OPINION

Although chronomodulated treatments have shown promising results, particularly for cancer, the practice is still underdeveloped due to the associated high cost and time investments. However, implementing this strategy at the preclinical stage could offer a new opportunity to translate preclinical discoveries into successful clinical treatments.

Succinate prodrugs as treatment for acute metabolic crisis during fluoroacetate intoxication in the rat

Sodium fluoroacetate (FA) is a metabolic poison that systemically inhibits the tricarboxylic acid (TCA) cycle, causing energy deficiency and ultimately multi-organ failure. It poses a significant threat to society because of its high toxicity, potential use as a chemical weapon and lack of effective antidotal therapy. In this study, we investigated cell-permeable succinate prodrugs as potential treatment for acute FA intoxication. We hypothesized that succinate prodrugs would bypass FA-induced mitochondrial dysfunction, provide metabolic support, and prevent metabolic crisis during acute FA intoxication. To test this hypothesis, rats were exposed to FA (0.75 mg/kg) and treated with the succinate prodrug candidate NV354. Treatment efficacy was evaluated based on cardiac and cerebral mitochondrial respiration, mitochondrial content, metabolic profiles and tissue pathology. In the heart, FA increased concentrations of the TCA metabolite citrate (+ 4.2-fold, p < 0.01) and lowered ATP levels (- 1.9-fold, p < 0.001), confirming the inhibition of the TCA cycle by FA. High-resolution respirometry of cardiac mitochondria further revealed an impairment of mitochondrial complex V (CV)-linked metabolism, as evident by a reduced phosphorylation system control ratio (- 41%, p < 0.05). The inhibition of CV-linked metabolism is a novel mechanism of FA cardiac toxicity, which has implications for drug development and which NV354 was unable to counteract at the given dose. In the brain, FA induced the accumulation of β-hydroxybutyrate (+ 1.4-fold, p < 0.05) and the reduction of mitochondrial complex I (CI)-linked oxidative phosphorylation (OXPHOSCI) (- 20%, p < 0.01), the latter of which was successfully alleviated by NV354. This promising effect of NV354 warrants further investigations to determine its potential neuroprotective effects.

Sex and the basal mRNA synthesis machinery

Evolution and change generated an incredible diversity of organisms on this earth. Yet, some processes are so central to life that change is strongly selected against. Synthesis of the eukaryotic messenger RNA is one example. The assemblies that carry out transcription and processing (capping, polyadenylation, and splicing) are so conserved that most genes have recognizable orthologs in yeast and humans. Naturally, most would conclude transcription and processing are identical in both sexes. However, this is an assumption. Men and women vastly differ in their physiologies. The incidence of pathologies, symptom presentation, disease outcome, and therapeutic response in each sex vary enormously. Despite the harm ignorance causes women, biological research has been historically carried out without regard to sex. The male mouse was the default mammal. A cultured cell's sex was considered irrelevant. Attempts to fill this knowledge gap have revealed molecular dissimilarities. For example, the earliest embryonic male and female transcriptomes differ long before fetal sex hormones appear. We used public data to challenge the assumption of sameness by reviewing reports of sex-biased gene expression and gene targeting. We focused on 120 genes encoding nonregulatory proteins involved in mRNA synthesis. Remarkably, genes with recognizable orthologs in yeast and thus LEAST likely to differ, did differ between the sexes. The rapidly growing public databases can be used to compare the expression of any gene in male and female tissues. Appreciating the principles that drive sex differences will enrich our understanding of RNA biology in all humans-men and women. This article is categorized under: RNA in Disease and Development > RNA in Development RNA Evolution and Genomics > Computational Analyses of RNA.

Predictors of treatment refusal in patients with colorectal cancer: A systematic review

This systematic review was conducted to investigate predictors of treatment refusal in colorectal cancer (CRC) patients. An understanding of these predictors would inform statistical models for the identification of high-risk patients who might benefit from interventions that seek to improve treatment compliance. We performed a search of PubMed and Scopus to identify potentially relevant studies on predictors of treatment refusal in CRC patients that were published between January 1, 2000 and December 31, 2021. We screened manuscripts using predefined eligibility criteria. Information on study design, study location, patient characteristics, treatments, rates and predictors of treatment refusal, and the impact of treatment refusal on mortality or survival were collected from eligible studies. Study quality was assessed using the Newcastle-Ottawa score. The overall findings of the review process were summarized using descriptive statistics and a narrative synthesis. A total of 13 studies were included in this review. Ten studies reported on refusal of CRC surgery, refusal rate: 0.25%-3.26%; three studies reported on chemotherapy refusal (one of which reported on both surgery and chemotherapy refusal), refusal rate: 7.8%-41.5%; and one study reported on refusal of any cancer treatment, refusal rate: 8.7%. The bulk of the published literature confirmed the harmful association between treatment refusal and poor survival outcomes in CRC patients. Frequently cited predictors of treatment refusal included patient demographic characteristics (age, race, gender), clinical characteristics (disease stage, comorbidity), and factors that impact access to cancer care services (healthcare insurance, facility level). Potentially high rates of treatment refusal pose a challenge to CRC control. This review has identified several factors which must be considered when attempting to reduce treatment refusal in CRC patients. Furthermore, these factors should be tested as components of predictive risk models for this important outcome.

Sex-Dependent Differences in Colorectal Cancer: With a Focus on Obesity

Colorectal cancer (CRC) is the third most common cancer and has the second highest cancer-related mortality in the world. The incident rates of CRC vary country-wise; however, population studies and data from different countries show a general increase in the CRC rate in young adults, males, and females ≥65 years. CRC incidence is affected by age, sex, environmental, dietary, hormonal, and lifestyle factors. Obesity is a known disease that is spreading rapidly throughout the world. A large body of literature indicates that, among many conditions, obesity is the increasing cause of CRC. Even though obesity is one of the known factors for CRC development, limited studies are available that explain the mechanistic link between obesity, sex hormones, and CRC development. Thus, this review summarizes the literature and aims to understand sex-dependent differences in CRC, especially in the context of obesity.

Sex-related differences in oxaliplatin-induced changes in the expression of transient receptor potential channels and their contribution to cold hypersensitivity

Transient receptor potential (TRP) channels are involved in the development of oxaliplatin-induced neuropathic pain, a frequent and debilitating side effect of cancer therapy. Here we explored whether oxaliplatin-induced changes in the expression of TRP channels, as well as the development of pain-related behaviours, differed between male and female animals. Adult rats were injected with oxaliplatin or saline and mechanical and cold allodynia were evaluated using Von Frey and Choi Tests. The mRNA levels of TRPV1, TRPM8 and TRPA1 were assessed in lumbar ganglia and spinal cord by using real time RT-PCR. Oxaliplatin administration induced mechanical and cold hypersensitivity and allodynia in both sexes, with more severe responses to cold stimulation detected in females. Oxaliplatin also induced a significant increase in the expression of TRPV1, TRPM8 and TRPA1 in lumbar dorsal root ganglia. Interestingly, while TRPV1 and TRPA1 upregulation showed no sex difference, the increase in TRPM8 mRNA levels was more pronounced in female ganglia, correlating with the increased sensitivity to innocuous cold stimuli observed in females. TRPV1 and TRPM8 were also found to be upregulated in the spinal cord of animals of both sexes. Our results reveal previously undescribed changes in the expression of TRP channels occurring in peripheral ganglia and spinal cord of both male and female oxaliplatin-treated animals, with some of these changes exhibiting sex-related differences that could underlie the development of sex-specific patterns of pain-related behaviours.

Effects of single-nucleotide polymorphism on the pharmacokinetics and pharmacodynamics of metformin

INTRODUCTION

Metformin has been recognized as the first-choice drug for type 2 diabetes mellitus (T2DM). The potency of metformin in the treatment of type 2 diabetes has always been in the spotlight and shown significant individual differences. Based on previous studies, the efficacy of metformin is related to the single-nucleotide polymorphisms of transporter genes carried by patients, amongst which a variety of gene polymorphisms of transporter and target protein genes affect the effectiveness and adverse repercussion of metformin.

AREAS COVERED

Here, we reviewed the current knowledge about gene polymorphisms impacting metformin efficacy based on transporter and drug target proteins.

EXPERT OPINION

The reason for the difference in clinical drug potency of metformin can be attributed to the gene polymorphism of drug transporters and drug target proteins in the human body. Substantial evidence shows that genetic polymorphisms in transporters such as organic cation transporter 1 (OCT1) and organic cation transporter 2 (OCT2) affect the glucose-lowering effectiveness of metformin. However, optimization of individualized dosing regimens of metformin is necessary to clarify the role of several polymorphisms.