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result(s) for
"Carleton, Bruce"
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All-trans retinoic acid (ATRA) regulates key genes in the RARG-TOP2B pathway and reduces anthracycline-induced cardiotoxicity
2022
The effectiveness of anthracycline chemotherapeutics (e.g., doxorubicin) is limited by anthracycline-induced cardiotoxicity (ACT). A nonsynonymous variant (S427L) in the retinoic acid receptor-γ (
RARG
) gene has been associated with ACT. This variant causes reduced RARG activity, which is hypothesized to lead to increased susceptibility to ACT through reduced activation of the retinoic acid pathway. This study explored the effects of activating the retinoic acid pathway using a RAR-agonist, all-trans retinoic acid (ATRA), in human cardiomyocytes and mice treated with doxorubicin. In human cardiomyocytes, ATRA induced the gene expression of
RAR
s (
RARG
,
RARB
) and repressed the expression of topoisomerase II enzyme genes (
TOP2A
,
TOP2B
), which encode for the molecular targets of anthracyclines and repressed downstream ACT response genes. Importantly, ATRA enhanced cell survival of human cardiomyocytes exposed to doxorubicin. The protective effect of ATRA was also observed in a mouse model (B6C3F1/J) of ACT, in which ATRA treatment improved heart function compared to doxorubicin-only treated mice. Histological analyses of the heart also indicated that ATRA treatment reduced the pathology associated with ACT. These findings provide additional evidence for the retinoic acid pathway’s role in ACT and suggest that the RAR activator ATRA can modulate this pathway to reduce ACT.
Journal Article
Pharmacogenetic variants in TPMT alter cellular responses to cisplatin in inner ear cell lines
by
Ross, Colin J. D.
,
Bhavsar, Amit P.
,
Hasbullah, Jafar S.
in
6-Mercaptopurine
,
Adenosylmethionine
,
Adults
2017
Cisplatin is a highly-effective and widely-used chemotherapeutic agent that causes ototoxicity in many patients. Pharmacogenomic studies of key genes controlling drug biotransformation identified variants in thiopurine methyltransferase (TPMT) as predictors of cisplatin-induced ototoxicity, although the mechanistic basis of this interaction has not been reported. Expression constructs of TPMT*3A, *3B and *3C variants were generated and monitored in cultured cells. Cellular TPMT*3A levels were detected at >20-fold lower amounts than the wild type confirming the unstable nature of this variant. The expression of wild type TPMT (TPMT*1) in two murine ear cell lines, HEI-OC1 and UB/OC-1, significantly mitigated their susceptibility to cisplatin toxicity. Cisplatin treatment induced Tlr4 gene expression in HEI-OC1 cells and this response was blunted by the expression of wild type TPMT but not TPMT*3A. In line with the significant mitigation of TPMT*1-expressing cells to cisplatin cytotoxicity, these findings demonstrate a drug-gene interaction between increased TPMT activity and decreased susceptibility to cisplatin-induced toxicity of inner ear cells.
Journal Article
The Role of Pharmacogenomics in Rare Diseases
by
Man, Alice
,
Ross, Colin J. D.
,
Groeneweg, Gabriella S. S.
in
Big Data
,
Chronic illnesses
,
Clinical medicine
2024
Rare diseases have become an increasingly important public health priority due to their collective prevalence and often life-threatening nature. Incentive programs, such as the
Orphan Drug Act
have been introduced to increase the development of rare disease therapeutics. While the approval of these therapeutics requires supportive data from stringent pre-market studies, these data lack the ability to describe the causes of treatment response heterogeneity, leading to medications often being more harmful or less effective than predicted. If a Goal Line were to be used to describe the multifactorial continuum of phenotypic variations occurring in response to a medication, the ‘Goal Posts’, or the two defining points of this continuum, would be (1) Super-Response, or an extraordinary therapeutic effect; and (2) Serious Harm. Investigation of the pharmacogenomics behind these two extreme phenotypes can potentially lead to the development of new therapeutics, help inform rational use criteria in drug policy, and improve the understanding of underlying disease pathophysiology. In the context of rare diseases where cohort sizes are smaller than ideal, ‘small data’ and ‘big data’ approaches to data collection and analysis should be combined to produce the most robust results. This paper presents the importance of studying drug response in parallel to other research initiatives in rare diseases, as well as the need for international collaboration in the area of rare disease pharmacogenomics.
Journal Article
Implementation of pharmacogenetic testing in oncology: DPYD-guided dosing to prevent fluoropyrimidine toxicity in British Columbia
by
Wu, Angela
,
Hughesman, Curtis
,
Lohrisch, Caroline
in
adverse drug reactions
,
clinical implementation
,
DPYD
2023
Background:
Fluoropyrimidine toxicity is often due to variations in the gene (
DPYD
) encoding dihydropyrimidine dehydrogenase (DPD).
DPYD
genotyping can be used to adjust doses to reduce the likelihood of fluoropyrimidine toxicity while maintaining therapeutically effective drug levels.
Methods:
A multiplex QPCR assay was locally developed to allow genotyping for six
DPYD
variants. The test was offered prospectively for all patients starting on fluoropyrimidines at the BC Cancer Centre in Vancouver and then across B.C., Canada as well as retrospectively for patients suspected to have had an adverse reaction to therapy. Dose adjustments were made for variant carriers. The incidence of toxicity in the first three cycles was compared between
DPYD
variant allele carriers and non-variant carriers. Subsequent to an initial implementation phase, this test was made available province-wide.
Results:
In 9 months, 186 patients were tested and 14 were found to be heterozygous variant carriers. Fluoropyrimidine-related toxicity was higher in
DPYD
variant carriers. Of 127 non-variant carriers who have completed chemotherapy, 18 (14%) experienced severe (grade ≥3, Common Terminology Criteria for Adverse Events version 5.0). Of note, 22% (3 patients) of the variant carriers experienced severe toxicity even after
DPYD
-guided dose reductions. For one of these carriers who experienced severe thrombocytopenia within the first week,
DPYD
testing likely prevented lethal toxicity. In
DPYD
variant carriers who tolerate reduced doses, a later 25% increase led to chemotherapy discontinuation. As a result, a recommendation was made to clinicians based on available literature and expert opinion specifying that variant carriers who tolerated two cycles without toxicity can have a dose escalation of only 10%.
Conclusion:
DPYD
-guided dose reductions were a feasible and acceptable method of preventing severe toxicity in
DPYD
variant carriers. Even with dose reductions, there were variant carriers who still experienced severe fluoropyrimidine toxicity, highlighting the importance of adhering to guideline-recommended dose reductions. Following the completion of the pilot phase of this study,
DPYD
genotyping was made available province-wide in British Columbia.
Journal Article
Fluoroquinolone Use and Risk of Carpal Tunnel Syndrome: A Pharmacoepidemiologic Study
2017
Fluoroquinolone-induced peripheral neuropathies and tendinopathies are well documented, but there are no epidemiologic studies on the risk of carpal tunnel syndrome (CTS). We conducted a case-control study of >6 million patients. Fluoroquinolone use is associated with increased risk of CTS (rate ratio, 1.34 [95% confidence interval, 1.31–1.37]).
Journal Article
Vaccinomics: A scoping review
by
Holroyd, Taylor A.
,
Dudley, Matthew Z.
,
Budigan Ni, Haley
in
Adverse events
,
Allergy and Immunology
,
Antibodies, Viral
2023
•Many genetic associations with vaccine immunogenicity have been identified.•Most genetic associations identified with Hepatitis B, MMR, and influenza vaccines.•Genetic associations were identified with 6 adverse events following immunization.•Vaccinomics is a growing field with great potential but need for investment.•Progress in vaccinomics could improve vaccine safety and effectiveness.
This scoping review summarizes a key aspect of vaccinomics by collating known associations between heterogeneity in human genetics and vaccine immunogenicity and safety.
We searched PubMed for articles in English using terms covering vaccines routinely recommended to the general US population, their effects, and genetics/genomics. Included studies were controlled and demonstrated statistically significant associations with vaccine immunogenicity or safety. Studies of Pandemrix®, an influenza vaccine previously used in Europe, were also included, due to its widely publicized genetically mediated association with narcolepsy.
Of the 2,300 articles manually screened, 214 were included for data extraction. Six included articles examined genetic influences on vaccine safety; the rest examined vaccine immunogenicity. Hepatitis B vaccine immunogenicity was reported in 92 articles and associated with 277 genetic determinants across 117 genes. Thirty-three articles identified 291 genetic determinants across 118 genes associated with measles vaccine immunogenicity, 22 articles identified 311 genetic determinants across 110 genes associated with rubella vaccine immunogenicity, and 25 articles identified 48 genetic determinants across 34 genes associated with influenza vaccine immunogenicity. Other vaccines had fewer than 10 studies each identifying genetic determinants of their immunogenicity. Genetic associations were reported with 4 adverse events following influenza vaccination (narcolepsy, GBS, GCA/PMR, high temperature) and 2 adverse events following measles vaccination (fever, febrile seizure).
This scoping review identified numerous genetic associations with vaccine immunogenicity and several genetic associations with vaccine safety. Most associations were only reported in one study. This illustrates both the potential of and need for investment in vaccinomics. Current research in this field is focused on systems and genetic-based studies designed to identify risk signatures for serious vaccine reactions or diminished vaccine immunogenicity. Such research could bolster our ability to develop safer and more effective vaccines.
Journal Article
Beta-blocker use and COPD mortality: a systematic review and meta-analysis
by
Etminan, Mahyar
,
Carleton, Bruce
,
Jafari, Siavash
in
Adrenergic beta blockers
,
Adrenergic beta-Antagonists - therapeutic use
,
Analysis
2012
Background
Despite the benefits of beta-blockers in patients with established or sub-clinical coronary artery disease, their use in patients with chronic obstructive pulmonary disease (COPD) has been controversial. Currently, no systematic review has examined the impact of beta-blockers on mortality in COPD.
Methods
We systematically searched electronic bibliographic databases including MEDLINE, EMBASE and Cochrane Library for clinical studies that examine the association between beta-blocker use and all cause mortality in patients with COPD. Risk ratios across studies were pooled using random effects models to estimate a pooled relative risk across studies. Publication bias was assessed using a funnel plot.
Results
Our search identified nine retrospective cohort studies that met the study inclusion criteria. The pooled relative risk of COPD related mortality secondary to beta-blocker use was 0.69 (95% CI: 0.62-0.78; I
2
=82%).
Conclusion
The results of this review are consistent with a protective effect of beta-blockers with respect to all cause mortality. Due to the observational nature of the included studies, the possibility of confounding that may have affected these results cannot be excluded. The hypothesis that beta blocker therapy might be of benefit in COPD needs to be evaluated in randomised controlled trials.
Journal Article
Genetic Variants in SLC22A17 and SLC22A7 are Associated With Anthracycline-Induced Cardiotoxicity in Children
by
Caron, Huib N
,
Kremer, Leontien C
,
Sandor, George S
in
Analysis
,
Anthracyclines
,
Anthracyclines - adverse effects
2015
To identify novel variants associated with anthracycline-induced cardiotoxicity and to assess these in a genotype-guided risk prediction model.
Two cohorts treated for childhood cancer (n = 344 and 218, respectively) were genotyped for 4578 SNPs in drug ADME and toxicity genes.
Significant associations were identified in SLC22A17 (rs4982753; p = 0.0078) and SLC22A7 (rs4149178; p = 0.0034), with replication in the second cohort (p = 0.0071 and 0.047, respectively). Additional evidence was found for SULT2B1 and several genes related to oxidative stress. Adding the SLC22 variants to the prediction model improved its discriminative ability (AUC 0.78 vs 0.75 [p = 0.029]).
Two novel variants in SLC22A17 and SLC22A7 were significantly associated with anthracycline-induced cardiotoxicity and improved a genotype-guided risk prediction model, which could improve patient risk stratification.
Journal Article
Genetic variants in TPMT and COMT are associated with hearing loss in children receiving cisplatin chemotherapy
by
Carleton, Bruce C
,
Rassekh, S Rod
,
Visscher, Henk
in
Agriculture
,
Animal Genetics and Genomics
,
Antineoplastic Agents - adverse effects
2009
Colin Ross and colleagues report the association of variants in
TPMT
and
COMT
to cisplatin-induced hearing loss in children.
Cisplatin is a widely used and effective chemotherapeutic agent, although its use is restricted by the high incidence of irreversible ototoxicity associated with it
1
. In children, cisplatin ototoxicity is a serious and pervasive problem, affecting more than 60% of those receiving cisplatin
2
,
3
,
4
,
5
and compromising language and cognitive development. Candidate gene studies have previously reported associations of cisplatin ototoxicity with genetic variants in the genes encoding glutathione S-transferases and megalin
6
,
7
,
8
. We report association analyses for 220 drug-metabolism genes in genetic susceptibility to cisplatin-induced hearing loss in children. We genotyped 1,949 SNPs in these candidate genes in an initial cohort of 54 children treated in pediatric oncology units, with replication in a second cohort of 112 children recruited through a national surveillance network for adverse drug reactions in Canada. We identified genetic variants in
TPMT
(rs12201199,
P
value = 0.00022, OR = 17.0, 95% CI 2.3–125.9) and
COMT
(rs9332377,
P
value = 0.00018, OR = 5.5, 95% CI 1.9–15.9) associated with cisplatin-induced hearing loss in children.
Journal Article
The Canadian Mother-Child Cohort Active Surveillance Initiative (CAMCCO): Comparisons between Quebec, Manitoba, Saskatchewan, and Alberta
2022
Background Given that pregnant women taking medications are excluded from clinical trials, real-world evidence is essential. We aimed to build a Canadian Mother-Child Cohort Active Surveillance Initiative (CAMCCO) and compare frequency of prematurity, low-birth-weight (LBW), major malformations, multiplicity, and gestational medication use across four provinces. Methods CAMCCO is a collaborative research infrastructure that uses real-world data from large provincial health care databases in Canada; developed with standardized methods to similarly construct population-based pregnancy/child cohorts with longitudinal follow-up by linking administrative/hospital/birth databases. CAMCCO also includes a common repository to i) share algorithms and case definitions based on diagnostic and procedural codes for research/training purpose, and ii) download aggregate data relevant to primary care providers, researchers, and decision makers. For this study, data from Quebec (1998-2015), Manitoba (1995-2019), Saskatchewan (1996-2020), and Alberta (2005-2018) are compared (Chi-square tests, p-values), and trends are calculated using Cochran-Armitage trend tests. Results Almost two-thirds (61%) of women took medications during pregnancy, mostly antibiotics (26%), asthma drugs (8%), and antidepressants (4%). Differences in the prevalence of prematurity (5.9-6.8%), LBW (4.0-5.2%), and multiplicity (1.0-2.5%) were statistically significant between provinces (p<0.001). Frequency of major malformations increased over time in Quebec (7-11%; p<0.001), Saskatchewan (5-11%; p<0.001), and Alberta (from 7-8%; p<0.001), and decreased in Manitoba (5-3%; p<0.001). Cardiovascular and musculoskeletal malformations were the most prevalent. Interpretation Medications are often used among Canadian pregnancies but adverse pregnancy outcomes vary across provinces. Digitized health data may help researchers and care providers understand the risk-benefit ratios related to gestational medication use, as well as province-specific trends.
Journal Article