Prostanoid signaling in retinal vascular diseases.

The vasculature of the retina is exposed to systemic and local factors that have the capacity to induce several retinal vascular diseases, each of which may lead to vision loss. Prostaglandin signaling has arisen as a potential therapeutic target for several of these diseases due to the diverse manners in which these lipid mediators may affect retinal blood vessel function. Previous reports and clinical practices have investigated cyclooxygenase (COX) inhibition by nonsteroidal anti-inflammatory drugs (NSAIDs) to address retinal diseases with varying degrees of success; however, targeting individual prostanoids or their distinct receptors affords more signaling specificity and poses strong potential for therapeutic development. This review offers a comprehensive view of prostanoid signaling involved in five key retinal vascular diseases: retinopathy of prematurity, diabetic retinopathy, age-related macular degeneration, retinal occlusive diseases, and uveitis. Mechanistic and clinical studies of these lipid mediators provide an outlook for therapeutic development with the potential to reduce vision loss in each of these conditions.

Psychiatric medication use among pregnant and breastfeeding mothers who used cannabis for mental health concerns: A cross-sectional survey study.

BACKGROUND: Use of cannabis during pregnancy and breastfeeding is increasing. Mental health concerns are reported as common reasons for maternal cannabis use, but little is known about the use of psychiatric medications in this population. OBJECTIVES: This study aimed to describe psychiatric medication use among pregnant and breastfeeding mothers who used cannabis for mental health concerns. DESIGN: Anonymous, online cross-sectional survey. METHODS: Data were collected from May 2018 to August 2019 among pregnant and breastfeeding mothers who used cannabis. This study included mothers who reported cannabis use for mental health concerns (n = 1363). The survey assessed the timing of cannabis use (during pregnancy and/or lactation); use of cannabis to address depression, posttraumatic stress disorder, or anxiety; use of psychiatric medications; psychiatric distress (Patient Health Questionnaire-4); and demographic information. Differences between groups were examined using t-test and chi-square test in SPSS. RESULTS: The mean age was 29.7 years; most were married (62%); 74% were White non-Hispanic, 9% Hispanic, and 17% Black, Indigenous or other People of Color. Mental health symptoms prompting cannabis use included anxiety (96%), depression (75%), and posttraumatic stress disorder (36%). Only 24% of respondents (n = 322) reported concomitant use of psychiatric medications, primarily selective serotonin reuptake inhibitors (72%, n = 232) and benzodiazepines (21%, n = 68). The composite Patient Health Questionnaire-4 showed most respondents had no (61%) or mild (27%) psychological distress; 14% screened positive for depression; and 17% screened positive for anxiety. Respondents who used psychiatric medications more often screened positive mental health concerns. CONCLUSION: Most mothers who used cannabis for mental health concerns were not taking psychiatric medications. This may be due to a mismatch between perceived mental health and screening results, un- or under-treated mental illness, or preference for cannabis over psychiatric medications. Improved management of perinatal mental health and effective patient education about risks of cannabis versus medication use are needed.

Psychiatric Manifestations of Withdrawal Following Domperidone Used as a Galactagogue.

Background: Domperidone is a dopamine-2 antagonist used off-label to increase breast milk production. Dosages commonly promoted for lactation are often far above those of studied on-label indications and might pose additional risks, especially upon discontinuation of the drug. Patients: Three U.S. patients are presented who used domperidone for lactation and experienced varying degrees of psychiatric withdrawal symptoms lasting months during dosage tapering and after cessation. Conclusion: Domperidone as a galactagogue may pose a significant psychiatric risk upon discontinuation. This presentation is commonly confused with, but clinically distinct from, postpartum depression. Lactating mothers who present with psychiatric symptoms should be explicitly probed about domperidone use, even in areas where domperidone is not authorized for use. Maternal hesitancy to disclose domperidone use may lead to suboptimal outcomes for the patient and delay management of withdrawal manifestations. The best course of treatment remains unknown, but a slow hyperbolic taper to gently discontinue domperidone may minimize withdrawal symptoms in these patients. Individuals exploring domperidone use should be informed of potential risks upon withdrawal, including psychiatric manifestations, requisite taper, and potential impacts of using unstudied high doses.

Concordance for Gender Dysphoria in Genetic Female Monozygotic (Identical) Triplets.

The biopsychosocial etiology of gender dysphoria is poorly understood, but current thought suggests a complex interaction of genetic, hormonal, environmental, and differences in brain development and physiology. Twin studies have implicated a genetic role in the formation of gender identity. Congruence for gender dysphoria is more common among monozygotic twins compared to dizygotic twins. We present a case of monozygotic (identical) triplets who have each transitioned from female to male under the care of a university transgender health service. Each triplet experienced gender dysphoria from childhood and has undergone transitional endocrine care and various aspects of gender-affirming surgery. Although a pure genetic or biological component cannot be attributed as a cause of their gender dysphoria with absolute certainty since the triplets were raised together, this unusual case of gender dysphoria among a set of monozygotic triplets adds support for a heritable role in gender identity formation.

Evaluation of cell-free DNA as a diagnostic marker in cerebrospinal fluid of dogs.

OBJECTIVE: To determine whether cell-free DNA (cfDNA) was detectable in CSF samples from dogs, whether CSF sample volume impacted CSF cfDNA concentration measurement, and whether CSF cfDNA concentration was associated with CNS disease category or CSF RBC count (RBCC), nucleated cell count (NCC), or protein concentration, which could aid in the diagnosis of neurologic diseases in dogs. SAMPLE: 80 CSF samples collected from dogs with (n = 60) and without (20) clinical neurologic disease between February 2017 and May 2018. PROCEDURES: Results for CSF RBCC, NCC, protein concentration, and cfDNA concentration were compared across CSF groups established on the basis of whether they were obtained from dogs with (case groups) or without (control group) clinical signs of neurologic disease In addition, 5 paired CSF samples representing large (3.0-mL) and small (0.5-mL) volumes, were used to evaluate whether sample volume impacted measurement of CSF cfDNA concentration. RESULTS: cfDNA was detected in 76 of the 80 (95%) CSF samples used to evaluate parameters across disease categories and in all 5 of the paired samples used to evaluate whether sample volume impacted cfDNA quantification. There were no substantial differences in cfDNA concentrations identified between groups (on the basis of disease category or sample volume), and the CSF cfDNA concentration did not meaningfully correlate with CSF RBCC, NCC, or protein concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Although results indicated that the CSF cfDNA concentration could not be used to differentiate between categories of neurologic disease in dogs of the the present study, further investigation is warranted regarding the use of CSF analysis, including sequencing specific cfDNA mutations, for diagnosing and monitoring neurologic disease in dogs.

Cannabis abuse and dependence in kidney transplant candidates.

OBJECTIVE: Cannabis is the most commonly used non-alcohol intoxicant in the general population. There are no consistent guidelines on the implications of cannabis abuse and dependence (CAD) in kidney transplant candidates. The aims of this study were to characterize kidney transplant candidates with comorbid CAD and examine the implications of CAD on transplant candidacy. METHOD: This was a retrospective cohort study of kidney transplant candidates meeting diagnostic criteria for CAD at a tertiary center from 2012 to 2016. Candidates were reviewed for psychiatric and substance use disorders (SUDs), family history, and medical variables. The cohort was divided by severity of CAD and transplant listing status for comparisons. Statistical analysis included Kruskal-Wallis tests for continuous variables and Fisher's Exact Test for categorical variables. RESULTS: Sixty-one of 2067 (3%) kidney transplant candidates met criteria for CAD, and 13/61 (21%) underwent transplantation. Of 61, 58% smoked cannabis daily, 47% had alcohol dependence history, 31% had other illicit drug dependencies, 38% were smokers, 60% had a SUD family history, and 42% and 27% had depressive and anxiety disorders, respectively. Severity of CAD was inversely associated with transplant listing; those with cannabis abuse were more often listed than those with dependence (67% vs 33%, p = .02) by study end. Three case presentations illustrate cannabis-related issues. CONCLUSION: In this cohort, kidney transplant candidates with comorbid CAD have high prevalence of other substance use disorders, psychiatric comorbidities, and strong family histories of addictions that resemble other SUD populations. These findings have implications for pre-transplant screening and treatment and post-transplant monitoring.

ALS-associated genes display CNS expression in the developing zebrafish.

Amyotrophic lateral sclerosis (ALS) is characterized by progressive muscle atrophy resulting from the deterioration of motor neurons in the central nervous system (CNS). Recent genome-wide association studies have revealed several genes linked to ALS, further demonstrating the complexity of the disease. The zebrafish (Danio rerio) is an attractive model organism to study the function of the rapidly expanding number of ALS-associated genes, in part, due to the development of genome editing techniques that have facilitated specific gene targeting. Before investing in the manipulation and phenotypic examination of these genes, however, it is important to ascertain the localization of expression in this organism. We performed an expression analysis of 29 total ALS-linked genes in the developing zebrafish, specifically focusing on those genes that displayed robust and reproducible expression at multiple different timepoints. First, we classified a subset of the most robustly expressed genes into three distinct groups: head-only expression, head and weak trunk expression, and head and robust trunk expression. Then, we defined the characteristic pattern of each gene at 2, 3, and 4 days post fertilization. This analysis will facilitate improved mutant phenotype assessment in zebrafish by focusing researchers on the areas of expression.

Use of a Gabapentin Protocol for the Management of Alcohol Withdrawal: A Preliminary Experience Expanding From the Consultation-Liaison Psychiatry Service.

BACKGROUND: Benzodiazepines are the conventional mainstay to manage alcohol withdrawal; however, patients are subsequently at increased risk for poor sleep, cravings, and return to drinking. Research on alternative pharmacologic agents to facilitate safe alcohol withdrawal is scant. Gabapentin is one medication shown in small studies to reduce the need for benzodiazepines in the setting of alcohol withdrawal. The continuation of gabapentin after alcohol withdrawal appears to be safe during early sobriety and may aid in reducing alcohol-related cravings or returning to alcohol consumption. Use of a gabapentin-based, benzodiazepine-sparing protool began in early 2015 by the Mayo Clinic, Rochester, Consultation-Liaison Psychiatry Service. OBJECTIVE: A retrospective chart review was conducted to detect any safety concerns with use of a gabapentin protocol for alcohol withdrawal syndrome. METHODS: Secondary outcomes were derived by comparing a matched cohort of patients who received benzodiazepines for alcohol withdrawal syndrome. RESULTS: Seventy-seven patients had their alcohol withdrawal managed via a gabapentin protocol during the study period. No patients required transfer to a higher level of care or had a documented withdrawal seizure. Length of stay between the gabapentin protocol group and benzodiazepine group were similar. CONCLUSION: This preliminary data has supported the frequent use of this protocol in the general internal medicine practice and formalization of an institutional order set of this protocol for mild to moderate alcohol withdrawal syndrome. Prospective studies are required to validate findings.

Identification of Novel Protein Expression Changes Following Cisplatin Treatment and Application to Combination Therapy.

Determining the effect of chemotherapeutic treatment on changes in protein expression can provide important targets for overcoming resistance. Due to challenges in simultaneously measuring large numbers of proteins, a paucity of data exists on global changes. To overcome these challenges, we utilized microwestern arrays that allowed us to measure the abundance and modification state of hundreds of cell signaling and transcription factor proteins in cells following drug exposure. HapMap lymphoblastoid cell lines (LCLs) were exposed to cisplatin, a chemotherapeutic agent commonly used to treat testicular, head and neck, non-small cell lung, and gynecological cancers. We evaluated the expression of 259 proteins following 2, 6, and 12 h of cisplatin treatment in two LCLs with discordant sensitivity to cisplatin. Of these 259 proteins, 66 displayed significantly different protein expression changes (p < 0.05). Fifteen of these proteins were evaluated in a second pair of LCLs with discordant sensitivities to cisplatin; six demonstrated significant differences in expression. We then evaluated a subset of 63 proteins in a second set of LCLs with discordant sensitivity, and 40% of those that were significant in the first pair were also significant in the second part with concordant directionality (p < 0.05). We functionally validated one of the top proteins identified, PDK1, and demonstrated a synergistic relationship between cisplatin and a PDK1 inhibitor in multiple lung cancer lines. This study highlights the potential for identifying novel targets through an understanding of cellular changes in protein expression and modification following drug treatments.

Genetic Variants Contributing to Colistin Cytotoxicity: Identification of TGIF1 and HOXD10 Using a Population Genomics Approach.

Colistin sulfate (polymixin E) is an antibiotic prescribed with increasing frequency for severe Gram-negative bacterial infections. As nephrotoxicity is a common side effect, the discovery of pharmacogenomic markers associated with toxicity would benefit the utility of this drug. Our objective was to identify genetic markers of colistin cytotoxicity that were also associated with expression of key proteins using an unbiased, whole genome approach and further evaluate the functional significance in renal cell lines. To this end, we employed International HapMap lymphoblastoid cell lines (LCLs) of Yoruban ancestry with known genetic information to perform a genome-wide association study (GWAS) with cellular sensitivity to colistin. Further association studies revealed that single nucleotide polymorphisms (SNPs) associated with gene expression and protein expression were significantly enriched in SNPs associated with cytotoxicity (p ≤ 0.001 for gene and p = 0.015 for protein expression). The most highly associated SNP, chr18:3417240 (p = 6.49 × 10-8), was nominally a cis-expression quantitative trait locus (eQTL) of the gene TGIF1 (transforming growth factor ß (TGFß)-induced factor-1; p = 0.021) and was associated with expression of the protein HOXD10 (homeobox protein D10; p = 7.17 × 10-5). To demonstrate functional relevance in a murine colistin nephrotoxicity model, HOXD10 immunohistochemistry revealed upregulated protein expression independent of mRNA expression in response to colistin administration. Knockdown of TGIF1 resulted in decreased protein expression of HOXD10 and increased resistance to colistin cytotoxicity. Furthermore, knockdown of HOXD10 in renal cells also resulted in increased resistance to colistin cytotoxicity, supporting the physiological relevance of the initial genomic associations.

Milbemycin oxime (Interceptor) treatment of amphipod parasites (Hyperiidae) from several host jellyfish species.

Wild-caught crystal jellyfish (Aequorea victoria) arrived at the John G. Shedd Aquarium infested with hyperiid amphipods (Hyperia medusarum), which were inadvertently introduced into a system containing several jellyfish species. Affected systems were treated with milbemycin oxime (Interceptor tablets for dogs 51-100 lbs, Novartis Animal Health US, Inc., Greensboro, North Carolina 27408, USA), a treatment prescribed for red bug (Tegastes acroporanus) infestation in corals. Two treatments using one 25-mg aliquot of Interceptor per 10 gallons of tank water administered 6-7 days apart were completed. Overall, treatment to eradicate the parasite from the affected systems was successful. Further studies evaluating the tolerance of jellyfish to milbemycin oxime, particularly in small juvenile Eutonina indicans and Aurelia aurita, are warranted. Based on clinical observations, there were more negative effects associated with the treatment in the hydrozoans than in the scyphozoans.

Identification and validation of genetic variants that influence transcription factor and cell signaling protein levels.

Many genetic variants associated with human disease have been found to be associated with alterations in mRNA expression. Although it is commonly assumed that mRNA expression changes will lead to consequent changes in protein levels, methodological challenges have limited our ability to test the degree to which this assumption holds true. Here, we further developed the micro-western array approach and globally examined relationships between human genetic variation and cellular protein levels. We collected more than 250,000 protein level measurements comprising 441 transcription factor and signaling protein isoforms across 68 Yoruba (YRI) HapMap lymphoblastoid cell lines (LCLs) and identified 12 cis and 160 trans protein level QTLs (pQTLs) at a false discovery rate (FDR) of 20%. Whereas up to two thirds of cis mRNA expression QTLs (eQTLs) were also pQTLs, many pQTLs were not associated with mRNA expression. Notably, we replicated and functionally validated a trans pQTL relationship between the KARS lysyl-tRNA synthetase locus and levels of the DIDO1 protein. This study demonstrates proof of concept in applying an antibody-based microarray approach to iteratively measure the levels of human proteins and relate these levels to human genome variation and other genomic data sets. Our results suggest that protein-based mechanisms might functionally buffer genetic alterations that influence mRNA expression levels and that pQTLs might contribute phenotypic diversity to a human population independently of influences on mRNA expression.

Protein quantitative trait loci identify novel candidates modulating cellular response to chemotherapy.

Annotating and interpreting the results of genome-wide association studies (GWAS) remains challenging. Assigning function to genetic variants as expression quantitative trait loci is an expanding and useful approach, but focuses exclusively on mRNA rather than protein levels. Many variants remain without annotation. To address this problem, we measured the steady state abundance of 441 human signaling and transcription factor proteins from 68 Yoruba HapMap lymphoblastoid cell lines to identify novel relationships between inter-individual protein levels, genetic variants, and sensitivity to chemotherapeutic agents. Proteins were measured using micro-western and reverse phase protein arrays from three independent cell line thaws to permit mixed effect modeling of protein biological replicates. We observed enrichment of protein quantitative trait loci (pQTLs) for cellular sensitivity to two commonly used chemotherapeutics: cisplatin and paclitaxel. We functionally validated the target protein of a genome-wide significant trans-pQTL for its relevance in paclitaxel-induced apoptosis. GWAS overlap results of drug-induced apoptosis and cytotoxicity for paclitaxel and cisplatin revealed unique SNPs associated with the pharmacologic traits (at p<0.001). Interestingly, GWAS SNPs from various regions of the genome implicated the same target protein (p<0.0001) that correlated with drug induced cytotoxicity or apoptosis (p ≤ 0.05). Two genes were functionally validated for association with drug response using siRNA: SMC1A with cisplatin response and ZNF569 with paclitaxel response. This work allows pharmacogenomic discovery to progress from the transcriptome to the proteome and offers potential for identification of new therapeutic targets. This approach, linking targeted proteomic data to variation in pharmacologic response, can be generalized to other studies evaluating genotype-phenotype relationships and provide insight into chemotherapeutic mechanisms.

The role of gene body cytosine modifications in MGMT expression and sensitivity to temozolomide.

The DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) is known to play a role in sensitivity to temozolomide. Promoter hypermethylation of MGMT is commonly used to predict low expression levels of MGMT in gliomas, despite observed discordance between promoter methylation and protein levels. Here, we investigated the functional role of gene body cytosine modification in regulating levels of MGMT gene expression and sensitivity to temozolomide. In 91 human glioblastoma samples, we observed significant variation in MGMT expression levels in patients with an unmethylated promoter, with higher levels of gene body cytosine modification correlating with higher gene expression levels. Furthermore, inducing hypomethylation across the MGMT gene body with decitabine corresponded with decreased levels of MGMT gene expression in lymphoblastoid and glioblastoma cell lines, indicating an important functional role for gene body cytosine modifications in maintaining gene expression. We reasoned that the decrease in MGMT expression induced by decitabine may render resistant glioblastoma cell lines more sensitive to temozolomide. Consistent with this reasoning, we found that the MGMT-expressing glioblastoma cell lines exhibiting an unmethylated MGMT promoter that were pretreated with decitabine became significantly more sensitive to temozolomide. Overall, our results suggest a functional role for gene body cytosine modification in regulating gene expression of MGMT and indicate that pretreating patients whose tumors have an unmethylated MGMT promoter with decitabine before temozolomide treatment may increase their response to therapy.

EPS8 inhibition increases cisplatin sensitivity in lung cancer cells.

Cisplatin, a commonly used chemotherapeutic, is associated with ototoxicity, renal toxicity and neurotoxicity, thus identifying means to increase the therapeutic index of cisplatin may allow for improved outcomes. A SNP (rs4343077) within EPS8, discovered through a genome wide association study of cisplatin-induced cytotoxicity and apoptosis in lymphoblastoid cell lines (LCLs), provided impetus to further study this gene. The purpose of this work was to evaluate the role of EPS8 in cellular susceptibility to cisplatin in cancerous and non-cancerous cells. We used EPS8 RNA interference to determine the effect of decreased EPS8 expression on LCL and A549 lung cancer cell sensitivity to cisplatin. EPS8 knockdown in LCLs resulted in a 7.9% increase in cisplatin-induced survival (P = 1.98 × 10(-7)) and an 8.7% decrease in apoptosis (P = 0.004) compared to control. In contrast, reduced EPS8 expression in lung cancer cells resulted in a 20.6% decrease in cisplatin-induced survival (P = 5.08 × 10(-5)). We then investigated an EPS8 inhibitor, mithramycin A, as a potential agent to increase the therapeutic index of cisplatin. Mithramycin A decreased EPS8 expression in LCLs resulting in decreased cellular sensitivity to cisplatin as evidenced by lower caspase 3/7 activation following cisplatin treatment (42.7% ± 6.8% relative to control P = 0.0002). In 5 non-small-cell lung carcinoma (NSCLC) cell lines, mithramycin A also resulted in decreased EPS8 expression. Adding mithramycin to 4 NSCLC cell lines and a bladder cancer cell line, resulted in increased sensitivity to cisplatin that was significantly more pronounced in tumor cell lines than in LCL lines (p<0.0001). An EGFR mutant NSCLC cell line (H1975) showed no significant change in sensitivity to cisplatin with the addition of mithramycin treatment. Therefore, an inhibitor of EPS8, such as mithramycin A, could improve cisplatin treatment by increasing sensitivity of tumor relative to normal cells.

Genetic and epigenetic variants contributing to clofarabine cytotoxicity.

2-chloro-2-fluoro-deoxy-9-D-arabinofuranosyladenine (Clofarabine), a purine nucleoside analog, is used in the treatment of hematologic malignancies and as induction therapy for stem cell transplantation. The discovery of pharmacogenomic markers associated with chemotherapeutic efficacy and toxicity would greatly benefit the utility of this drug. Our objective was to identify genetic and epigenetic variants associated with clofarabine toxicity using an unbiased, whole genome approach. To this end, we employed International HapMap lymphoblastoid cell lines (190 LCLs) of European (CEU) or African (YRI) ancestry with known genetic information to evaluate cellular sensitivity to clofarabine. We measured modified cytosine levels to ascertain the contribution of genetic and epigenetic factors influencing clofarabine-mediated cytotoxicity. Association studies revealed 182 single nucleotide polymorphisms (SNPs) and 143 modified cytosines associated with cytotoxicity in both populations at the threshold P ≤ 0.0001. Correlation between cytotoxicity and baseline gene expression revealed 234 genes at P ≤ 3.98 × 10(-6). Six genes were implicated as: (i) their expression was directly correlated to cytotoxicity, (ii) they had a targeting SNP associated with cytotoxicity, and (iii) they had local modified cytosines associated with gene expression and cytotoxicity. We identified a set of three SNPs and three CpG sites targeting these six genes explaining 43.1% of the observed variation in phenotype. siRNA knockdown of the top three genes (SETBP1, BAG3, KLHL6) in LCLs revealed altered susceptibility to clofarabine, confirming relevance. As clofarabine's toxicity profile includes acute kidney injury, we examined the effect of siRNA knockdown in HEK293 cells. siSETBP1 led to a significant change in HEK293 cell susceptibility to clofarabine.

Do male and female cowbirds see their world differently? Implications for sex differences in the sensory system of an avian brood parasite.

BACKGROUND: Male and female avian brood parasites are subject to different selection pressures: males compete for mates but do not provide parental care or territories and only females locate hosts to lay eggs. This sex difference may affect brain architecture in some avian brood parasites, but relatively little is known about their sensory systems and behaviors used to obtain sensory information. Our goal was to study the visual resolution and visual information gathering behavior (i.e., scanning) of brown-headed cowbirds. METHODOLOGY/PRINCIPAL FINDINGS: We measured the density of single cone photoreceptors, associated with chromatic vision, and double cone photoreceptors, associated with motion detection and achromatic vision. We also measured head movement rates, as indicators of visual information gathering behavior, when exposed to an object. We found that females had significantly lower density of single and double cones than males around the fovea and in the periphery of the retina. Additionally, females had significantly higher head-movement rates than males. CONCLUSIONS: Overall, we suggest that female cowbirds have lower chromatic and achromatic visual resolution than males (without sex differences in visual contrast perception). Females might compensate for the lower visual resolution by gazing alternatively with both foveae in quicker succession than males, increasing their head movement rates. However, other physiological factors may have influenced the behavioral differences observed. Our results bring up relevant questions about the sensory basis of sex differences in behavior. One possibility is that female and male cowbirds differentially allocate costly sensory resources, as a recent study found that females actually have greater auditory resolution than males.

Comprehensive genetic analysis of cytarabine sensitivity in a cell-based model identifies polymorphisms associated with outcome in AML patients.

A whole-genome approach was used to investigate the genetic determinants of cytarabine-induced cytotoxicity. We performed a meta-analysis of genome-wide association studies involving 523 lymphoblastoid cell lines (LCLs) from individuals of European, African, Asian, and African American ancestry. Several of the highest-ranked single-nucleotide polymorphisms (SNPs) were within the mutated in colorectal cancers (MCC) gene. MCC expression was induced by cytarabine treatment from 1.7- to 26.6-fold in LCLs. A total of 33 SNPs ranked at the top of the meta-analysis (P < 10(-5)) were successfully tested in a clinical trial of patients randomized to receive low-dose or high-dose cytarabine plus daunorubicin and etoposide; of these, 18 showed association (P < .05) with either cytarabine 50% inhibitory concentration in leukemia cells or clinical response parameters (minimal residual disease, overall survival (OS), and treatment-related mortality). This count (n = 18) was significantly greater than expected by chance (P = .016). For rs1203633, LCLs with AA genotype were more sensitive to cytarabine-induced cytotoxicity (P = 1.31 × 10(-6)) and AA (vs GA or GG) genotype was associated with poorer OS (P = .015), likely as a result of greater treatment-related mortality (P = .0037) in patients with acute myeloid leukemia (AML). This multicenter AML02 study trial was registered at www.clinicaltrials.gov as #NCT00136084.

Identification of novel germline polymorphisms governing capecitabine sensitivity.

BACKGROUND: Capecitabine, an oral 5-fluorouracil (5-FU) prodrug, is widely used in the treatment of breast, colorectal, and gastric cancers. To guide the selection of patients with potentially the greatest benefit of experiencing antitumor efficacy, or, alternatively, of developing toxicities, identifying genomic predictors of capecitabine sensitivity could permit its more informed use. METHODS: The objective of this study was to perform capecitabine sensitivity genome-wide association studies (GWAS) using 503 well genotyped human cell lines from individuals representing multiple different world populations. A meta-analysis that included all ethnic populations then enabled the identification of novel germline determinants (single nucleotide polymorphisms [SNPs]) of capecitabine susceptibility. RESULTS: First, an intrapopulation GWAS of Caucasian individuals identified reference SNP 4702484 (rs4702484) (within adenylate cyclase 2 [ADCY2]) at a level reaching genome-wide significance (P = 5.2 × 10(-8) ). This SNP is located upstream of the 5 methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR) gene, and it is known that the enzyme for MTRR is involved in the methionine-folate biosynthesis and metabolism pathway, which is the primary target of 5-FU-related compounds, although the authors were unable to identify a direct relation between rs4702484 and MTRR expression in a tested subset of cells. In the meta-analysis, 4 SNPs comprised the top hits, which, again, included rs4702484 and 3 additional SNPs (rs8101143, rs576523, and rs361433) that approached genome-wide significance (P values from 1.9 × 10(-7) to 8.8 × 10(-7) ). The meta-analysis also identified 1 missense variant (rs11722476; serine to asparagine) within switch/sucrose nonfermentable-related, matrix-associated, actin-dependent regulator of chromatin (SMARCAD1), a novel gene for association with capecitabine/5-FU susceptibility. CONCLUSIONS: Toward the goal of individualizing cancer chemotherapy, the current study identified novel SNPs and genes associated with capecitabine sensitivity that are potentially informative and testable in any patient regardless of ethnicity.