Unveiling Discrepant and Rare Dihydropyrimidine Dehydrogenase (DPYD) Results Using an In-House Genotyping Test: A Case Series

Fluoropyrimidine chemotherapy is a primary component of many solid tumor treatment regimens, particularly those for gastrointestinal malignancies. Approximately one-third of patients receiving fluoropyrimidine-based chemotherapies experience serious adverse effects. This risk is substantially higher in patients carrying DPYD genetic variants, which cause reduced fluoropyrimidine metabolism and inactivation (ie, dihydropyridine dehydrogenase [DPD] deficiency). Despite the known relationship between DPD deficiency and severe toxicity risk, including drug-related fatalities, pretreatment DPYD testing is not standard of care in the United States. We developed an in-house DPYD genotyping test that detects 5 clinically actionable variants associated with DPD deficiency, and genotyped 827 patients receiving fluoropyrimidines, of which 49 (6%) were identified as heterozygous carriers. We highlight 3 unique cases: (1) a patient with a false-negative result from a commercial laboratory that only tested for the c.1905 + 1G>A (*2A) variant, (2) a White patient in whom the c.557A>G variant (typically observed in people of African ancestry) was detected, and (3) a patient with the rare c.1679T>G (*13) variant. Lastly, we evaluated which DPYD variants are detected by commercial laboratories offering DPYD genotyping in the United States and found 6 of 13 (46%) did not test for all 5 variants included on our panel. We estimated that 20.4% to 81.6% of DPYD heterozygous carriers identified on our panel would have had a false-negative result if tested by 1 of these 6 laboratories. The sensitivity and negative predictive value of the diagnostic tests from these laboratories ranged from 18.4% to 79.6% and 95.1% to 98.7%, respectively. These cases underscore the importance of comprehensive DPYD genotyping to accurately identify patients with DPD deficiency who may require lower fluoropyrimidine doses to mitigate severe toxicities and hospitalizations. Clinicians should be aware of test limitations and variability in variant detection by commercial laboratories, and seek assistance by pharmacogenetic experts or available resources for test selection and result interpretation.

Thrombosis Rates and Genetic Thrombophilia Risk Among Patients With Advanced Germ Cell Tumors Treated With Chemotherapy

INTRODUCTION

Men with advanced germ cell tumors (GCT) treated with chemotherapy are at high risk of venous thromboembolism (VTE). Predictors of VTE may identify patients who would benefit from prophylactic anticoagulation.

PATIENTS AND METHODS

Men with advanced GCT (Stage IS, II, III) treated with chemotherapy were identified at 2 centers. High genomic risk was defined from a 5 single nucleotide polymorphism (SNP) germline panel. Logistic regression was used to evaluate the impact of genomic risk on VTE within 6 months of chemotherapy initiation. Orthogonal Projection to Latent Structures Discriminant Analysis (OPLS-DA) was used to build models to predict VTE based on clinical variables and an 86 SNP panel.

RESULTS

This 123-patient cohort experienced a VTE rate of 26% with an incidence of high genomic risk of 21%. Men with high genomic risk did not have a significantly higher VTE rate (31%, 8/26) than men with low genomic risk (25%, 24/97), unadjusted OR 1.4 (95% CI 0.5-3.5, P = .54). Incorporation of clinical variables (Khorana score, N3 status and elevated LDH) resulted in adjusted OR 2.1 (95% CI 0.7-6.5, P = .18). A combined model using clinical variables and 86 SNPs performed similarly (AUC 0.77) compared to clinical variables alone (AUC 0.72).

CONCLUSIONS

A previously established 5-SNP panel was not associated with VTE among patients with GCT receiving chemotherapy. However, multivariable models based on clinical variables alone warrant further validation to inform prophylactic anticoagulation strategies.

Genetic Predictors of Ibrutinib-related Cardiovascular Side Effects in Patients with Chronic Lymphocytic Leukemia

PURPOSE

Patients with chronic lymphocytic leukemia (CLL) treated with ibrutinib are at risk of developing cardiovascular side effects (CVSE). The molecular determinants of CVSEs have not been fully elucidated. We interrogated genetic polymorphisms in the Bruton tyrosine kinase (BTK) signaling pathway for their association with ibrutinib-related CVSEs.

EXPERIMENTAL DESIGN

We conducted a retrospective/prospective observational pharmacogenetic study of 50 patients with newly diagnosed or relapsed CLL who received ibrutinib at a starting daily dose of 420 mg for at least 6 months. CVSEs, primarily atrial fibrillation and hypertension, occurred in 10 patients (20%), of whom 4 discontinued therapy. DNA was isolated from buccal swabs of all 50 patients and genotyped for 40 SNPs in GATA4, SGK1, KCNQ1, KCNA4, NPPA, and SCN5A using a customized next-generation sequencing panel. Univariate and multivariate logistic regression analysis were performed to determine genetic and clinical factors associated with the incidence of ibrutinib-related CVSEs.

RESULTS

GATA4 rs804280 AA (P = 0.043), KCNQ1 rs163182 GG (P = 0.036), and KCNQ1 rs2237895 AA (P = 0.023) genotypes were univariately associated with ibrutinib-related CVSEs. On the basis of multivariate analysis, a high genetic risk score, defined as the presence of at least two of these genotypes, was associated with 11.5-fold increased odds of CVSEs (P = 0.019; 95% confidence interval, 1.79-119.73).

CONCLUSIONS

Our findings suggest possible genetic determinants of ibrutinib-related CVSEs in CLL. If replicated in a larger study, pretreatment pharmacogenetic testing for GATA4 and KCNQ1 polymorphisms may be a useful clinical tool for personalizing treatment selection for CLL and/or instituting early risk mitigation strategies.

Pharmacogenetic and clinical predictors of voriconazole concentration in hematopoietic stem cell transplant recipients receiving CYP2C19-guided dosing

CYP2C19-guided voriconazole dosing reduces pharmacokinetic variability, but many patients remain subtherapeutic. The aim of this study was to evaluate the effect of candidate genes and a novel CYP2C haplotype on voriconazole trough concentrations in patients receiving CYP2C19-guided dosing. This is a retrospective candidate gene study in allogeneic hematopoietic cell transplant (HCT) patients receiving CYP2C19-guided voriconazole dosing. Patients were genotyped for ABCB1, ABCG2, CYP2C9, CYP3A4, CYP3A5, and the CYP2C haplotype. Of 185 patients, 36% were subtherapeutic (of which 79% were normal or intermediate metabolizers). In all patients, CYP2C19 (p < 0.001), age (p = 0.018), and letermovir use (p = 0.001) were associated with voriconazole concentrations. In the subset receiving 200 mg daily (non-RM/UMs), CYP2C19 (p = 0.004) and ABCG2 (p = 0.015) were associated with voriconazole concentrations; CYP2C19 (p = 0.028) and letermovir use (p = 0.001) were associated with subtherapeutic status. CYP2C19 phenotype and letermovir use were significantly associated with subtherapeutic voriconazole concentrations and may be used to improve voriconazole precision dosing, while further research is needed to clarify the role of ABCG2 in voriconazole dosing.

Evaluation of pentamidine tolerability and efficacy between CYP2C19 phenotypes

Intravenous pentamidine is used for prophylaxis against Pneumocystis jirovecii pneumonia, an infection seen in hematopoietic stem cell transplant recipients. Pentamidine is partially metabolized by CYP2C19, which is vulnerable to pharmacogenetic variation. This retrospective study evaluated allogeneic hematopoietic stem cell transplant patients who received intravenous pentamidine as P. jirovecii pneumonia prophylaxis. The primary objective was the association between CYP2C19 phenotype and discontinuation of pentamidine due to drug-related side effects based on univariate logistic regression (N = 81). Ten patients (12.3%) discontinued pentamidine because of side effects. There was no difference in discontinuation between phenotype groups (p = 0.18) or discontinuation due to side effects (p = 0.76). Overall, no association was seen between phenotypes and pentamidine-related side effects (p = 0.475). Drug discontinuation rates and P. jirovecii pneumonia infection rates were low.

Addressing barriers to increased adoption of DPYD genotyping at a large multisite cancer center

PURPOSE

To describe the implementation of an in-house genotyping program to detect genetic variants linked to impaired dihydropyrimidine dehydrogenase (DPD) metabolism at a large multisite cancer center, including barriers to implementation and mechanisms to overcome barriers to facilitate test adoption.

SUMMARY

Fluoropyrimidines, including fluorouracil and capecitabine, are commonly used chemotherapy agents in the treatment of solid tumors, such as gastrointestinal cancers. DPD is encoded by the DPYD gene, and individuals classified as DPYD intermediate and poor metabolizers due to certain genetic variations in DPYD can experience reduced fluoropyrimidine clearance and an increased risk of fluoropyrimidine-related adverse events. Although pharmacogenomic guidelines provide evidence-based recommendations for DPYD genotype-guided dosing, testing has not been widely adopted in the United States for numerous reasons, including limited education/awareness of clinical utility, lack of testing recommendations by oncology professional organizations, testing cost, lack of accessibility to a comprehensive in-house test and service, and prolonged test turnaround time. Based on stakeholder feedback regarding barriers to testing, we developed an in-house DPYD test and workflow to facilitate testing in multiple clinic locations at Levine Cancer Institute. Across 2 gastrointestinal oncology clinics from March 2020 through June 2022, 137 patients were genotyped, and 13 (9.5%) of those patients were heterozygous for a variant and identified as DPYD intermediate metabolizers.

CONCLUSION

Implementation of DPYD genotyping at a multisite cancer center was feasible due to operationalization of workflows to overcome traditional barriers to testing and engagement from all stakeholders, including physicians, pharmacists, nurses, and laboratory personnel. Future directions to scale and sustain testing in all patients receiving a fluoropyrimidine across all Levine Cancer Institute locations include electronic medical record integration (eg, interruptive alerts), establishment of a billing infrastructure, and further refinement of workflows to improve the rate of pretreatment testing.

Genetic alterations in tumor tissue and cell-free DNA in patients with papillary thyroid carcinoma at initial surgery

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Background: The value of sequencing cell-free DNA (cfDNA) from patients with papillary carcinoma of the thyroid (PTC) is controversial. Studies utilizing whole-exome sequencing (WES) or single-gene detection methods have reported lower mutational yield in cfDNA in PTC compared with other cancers. Alternatively, mutational analyses of anaplastic thyroid carcinoma (ATC), which is thought to evolve from PTC, demonstrate high levels of mutated cfDNA. We report on mutations in tumor and cfDNA at initial surgery for PTC, correlate with clinicopathologic status and further characterize the mutational landscape of these tumors in tissue and blood utilizing deep-sequencing panel testing. Methods: 50 patients were enrolled 2017-2020. Tempus xT (648 genes) and xF (105 genes) panels were used to prepare next generation sequencing libraries from tissue and blood samples, respectively. Cell-free DNA (cfDNA) sequencing depth average is 20,000x (raw reads)/5,000x (unique reads). Results: More than half of the patients had pT3-T4 tumors and/or local metastases and one had distant metastasis. 47/47 (100%) of processable tissue samples and 40/49 (81.6%) of blood samples yielded at least one relevant mutation. BRAF V600E was found in 77% of tissue and 8% of cfDNA, while mutated TERT was detected in 17% of tissue and none of the blood samples. The most frequently mutated genes in cfDNA were KMT2A (18% of blood samples, 6 % tissue), ATM (12% blood, 6% tissue), and TP53 (12% blood, 2 % tissue). There was marked mutational heterogeneity among samples, and a range of alterations representing multiple oncogenic pathways. Conclusions: Patients at initial surgery demonstrated highly mutated tissue DNA, including BRAF, TERT and other mutations known to be found in PTC. The most frequent tissue mutations were found at higher rates than previously reported by WES, which may reflect the sensitivity of targeted deep sequencing versus WES, and possibly a selection bias of more advanced PTC. A high percentage of cfDNA samples yielded mutations relevant to thyroid cancer, and the absence of TERT is consistent with prior studies. Mutations and co-mutations associated with de-differentiation and worse outcomes were demonstrated in both tissue and cfDNA. Interestingly, mutations more common in ATC than PTC, such as TP53, were detected in cfDNA, often without primary tumor correlate. Since mutations associated with aggressive behavior may be found in metastatic foci while not detected in the primary tumor, we conclude that cfDNA may reveal prognostic information important for the development of surveillance strategies in selected patients with residual PTC after surgery who may be at risk for poor outcomes.

Identification of genetic markers associated with ibrutinib-related cardiovascular toxicity

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Background: Cardiovascular side effects (CVSEs: atrial fibrillation, hypertension, etc.) are common in patients with chronic lymphocytic leukemia (CLL) treated with ibrutinib and often lead to dose reductions or discontinuation. However, the etiology of ibrutinib related CVSEs has not been elucidated. This study sought to interrogate the association between ibrutinib related CVSEs and polymorphisms in genes of the Bruton Tyrosine Kinase (BTK) signaling pathway (identified through Ingenuity Pathway Analysis) Methods: Newly diagnosed and relapsed patients with CLL who underwent treatment with ibrutinib between December 2019 and November 2020 at Levine Cancer Institute were identified. Buccal swabs were collected through an IRB approved specimen collection protocol. Data extraction included: demographics, CLL stage, cytogenetics, previous treatments, ibrutinib start dates and dose, drug related SEs, and other medications. DNA isolated from buccal swabs was genotyped for 40 single nucleotide polymorphisms (SNPs) in GATA4, SGK1, KCNQ1, KCNA4, NPPA and SCN5A genes using a custom NGS panel. Logistic regression analysis evaluated the association between SNPs and CVSEs. Results: In 50 evaluable patients, the median age was 71 years (range:48-90) and 50% received frontline ibrutinib monotherapy. CVSEs occurred in 20% of patients (n=10). In univariate analysis, 4 SNPs in 3 genes were significantly associated with CVSEs (Table). Because the genes were in the same pathway, a genetic risk score was developed which indicated that patients with at least 2 SNPs had a 12-fold increase in risk of CVSEs (Table). Conclusions: Our findings provide insights into the genetic determinants of ibrutinib related CVSEs. If replicated in a larger study, this will facilitate utility of pharmacogenetic testing (for GATA4, KCNQ1 and KCNA5 polymorphisms ) as a clinical tool to individualize ibrutinib treatment.[Table: see text]

North Carolina's multi-institutional pharmacogenomics efforts with the North Carolina Precision Health Collaborative

The North Carolina Precision Health Collaborative is an interdisciplinary, public-private consortium of precision health experts who strategically align statewide resources and strengths to elevate precision health in the state and beyond. Pharmacogenomics (PGx) is a key area of focus for the North Carolina Precision Health Collaborative. Experts from Atrium Health's Levine Cancer Institute, Duke University/Duke Health System, Mission Health and the University of North Carolina (UNC) at Chapel Hill/UNC Health System have collaborated since 2017 to implement strategic PGx initiatives, including basic sciences research, translational research and clinical implementation of germline testing into practice and policy. This institutional profile highlights major PGx programs and initiatives across these organizations and how the collaborative is working together to advance PGx science and implementation.

Ex vivo efficacy of BCMA-bispecific antibody TNB-383B in relapsed/refractory multiple myeloma

TNB-383B is a fully human BCMA-targeting T-cell engaging bispecific monoclonal antibody (T-BsAb). We assessed ex vivo efficacy of this drug to mediate killing of bone marrow mononuclear cells (BMMCs) freshly isolated from 10 patients with relapsed multiple myeloma (MM). BMMC were treated ex vivo with TNB-383B at doses ranging from 0.001-1 μg. Plasma cell (PC) lysis, viability, BCMA expression, CTL distribution, and degranulation were assessed by flow cytometry. Cytokine response to TNB-383B was quantified by multiplex protein assay. Dose-dependent PC lysis was triggered in all cases by TNB-383B at doses as low as 0.001 μg (P = .0102). Primary MM cells varied in BCMA expression. High BCMA+ PC count correlated with increased PC lysis (P = .005) and significant CTL degranulation specific to TNB-383B treatment (P = .0153 at 1 μg). High E:T ratio in bone marrow specimens led to lower viable and higher apoptotic PC compared with low E:T ratio (P < .001). Three cytokines were significantly modulated by TNB-383B: IL-2/TNFα increased by ∼4 ± 3.5-fold average (P < .005 at 1 μg) and IP10 increased by ∼50 ± 15-fold (P < .001 at 1 μg). We conclude that TNB-383B triggers primary PC lysis and CTL degranulation in a dose-dependent fashion ex vivo with no T cell expansion and mild increase of CRS-associated cytokines.

A pilot study evaluating the safety, tolerability, and efficacy of doxorubicin and pembrolizumab in patients with metastatic or unresectable soft tissue sarcoma

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Background: Doxorubicin has been the traditional standard therapy for treatment of advanced soft tissue sarcoma (STS). The addition of cytotoxic agents leads to increased toxicity with minimal improvement in efficacy. Pembrolizumab monotherapy has demonstrated activity and tolerability in previous study of advanced STS. This study combined pembrolizumab with doxorubicin to determine safety and efficacy in the frontline setting. Methods: This single-center, single-arm, phase 2 trial enrolled subjects with unresectable or metastatic STS and no prior anthracycline therapy. Subjects were treated with pembrolizumab 200 mg IV and doxorubicin 60 mg/m2 (75 mg/m2 dose escalation per investigator discretion) IV every 3 weeks. The primary endpoint of safety, based on Bayesian stopping rules, evaluated if the severe or life-threatening treatment emergent adverse event (TEAE) rate exceeded 0.55. Secondary endpoints included overall survival (OS), objective response rate (ORR), and progression free survival (PFS). Efficacy and safety were based on RECIST 1.1 and CTCAE v 4.0, respectively. Kaplan-Meier methods evaluated time to event outcomes. Results: From 4/2017 to 12/2019, 30 subjects (53% female, median age 61.5 years, 10 patients > 70 years (33%)) were enrolled in the study with 6 (20%) patients still on treatment and 27 evaluable for response. The most common histologic subtypes were leiomyosarcoma (33%) and liposarcoma (23%), and a majority of patients demonstrated high grade disease (60%). Current analysis shows a median follow-up of 9.9 months. One subject experienced a stopping rule event (grade 3 autoimmune disorder). ORR was 33% (95% CI 17-54%), with documented disease control in 78% (95% CI 57.7-91.4%) of patients. Eight (30%) patients achieved a partial response, one (4%) patient achieved a complete response and 12 (44%) patients had stable disease. Preliminary results demonstrate median PFS of 6.9 months (PFS-6 mo: 52%) and median OS of 15 months (OS-6 mo: 81%) compared to historical PFS-6mo of 4.6 months and OS of 12.8 months with doxorubicin alone.1 Most common grade 3+ TEAEs included neutropenia (11 [37%]), febrile neutropenia (6 [20%]), anemia (5 [17%]), and nausea (4 [13%]). Molecular and biomarker analysis is currently in progress. Conclusions: The combination of pembrolizumab with doxorubicin has manageable toxicity and preliminary promising activity in the treatment of anthracycline-naive advanced soft tissue sarcomas. Ref: 1. Lancet Oncol. 2014 Apr; 15(4):415-23. Clinical trial information: NCT03056001 .

Genetic polymorphisms associated with clostridium difficile infection in multiple myeloma patients undergoing autologous stem cell transplantation

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Background: CDI is the primary cause of infectious diarrhea in immunocompromised patients including those undergoing autologous stem cell transplant (SCT). Given the key role of gut microbiome and its interaction with host immune system, we investigated whether polymorphisms in innate immunity genes (identified through Ingenuity Pathway Analysis) were associated with CDI. Methods: We queried our database to identify MM patients who underwent an autologous SCT between April 2015-June 2019. Patients who had their buccal swabs collected through an IRB approved specimen collection protocol were included herein. Data were collected on age, conditioning regimen, CDI diagnosis, time from admission until CDI diagnosis, absolute neutrophil count (ANC) at time of CDI diagnosis, and antibiotic prophylaxis. Genomic DNA was extracted from buccal swabs and genotyped for 62 single nucleotide polymorphisms (SNPs) in ASPH , RLBP1L1, ATP7B, IL-8, FAK, TNFRSF14, CTH, TLR and IL-4. Univariate and multivariate logistic regression analyses were performed to assess association between CDI and presence of SNPs in these genes. Results: A total of 83 patients were identified (25 cases and 58 controls). Baseline characteristics were comparable between two groups. Median age was 67 years (range: 50-79). All patients received high dose melphalan as conditioning, and the same antibiotic prophylaxis during peri-transplant period. Median time from hospitalization until CDI diagnosis was 10 days (IQR:9 days), and median ANC was 0.7/mL (IQR:1.6/mL). Two SNPs (rs2227307 T > G in IL-8 and rs2234167 G > A in TNFRSF14) were significantly associated with CDI risk in both univariate and multivariate logistic regression analyses (Table). Conclusions: Our findings suggest that rs227307G (in IL-8) and rs2234167A (in TNFRSF14) alleles are potential risk factors for CDI after autologous SCT. Our findings, if validated in a larger cohort, would support genetic testing as a screening tool to identify patients who might benefit from prophylaxis against CDI. [Table: see text]

Pathogenic variants in PTEN to predict for increased risk of relapse and death in patients with limited stage small cell bladder cancer

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Background: Small cell bladder cancer (SCBC) is a rare histologic subtype with insufficient genomic characterization. Patients with limited stage (LS) SCBC have a poor prognosis, and no biomarker exists to optimize treatment selection. We sought to identify genomic aberrations in patients with LS-SCBC using a comprehensive next generation sequencing (NGS) platform. Mutations in the PTEN/AKT pathway are important in urothelial tumor biology but have an undefined role in SCBC. Methods: 23 LS-SCBC cases were identified. NGS was performed on diagnostic transurethral bladder tumor resection or cystectomy specimens containing SCBC. Detected variants were filtered by in silico algorithms predicting for a deleterious impact on protein function. Variant allele frequencies (VAF) greater than 2% were permitted in this analysis. Variants in the PTEN gene were assessed for association with relapse-free survival (RFS) and overall survival (OS) using Kaplan-Meier techniques and Cox proportional hazards models. Results: Median follow up for the cohort was 4.02 years. 14/23 (60.9%) patients have died. Six unique deleterious PTEN mutations were observed in 9/23 (39.1%) patients. p.W274C was the most common PTEN variant and was detected in 5 (21.7%) patients. Three variants were detected at > 10% VAF. All 9 patients with a deleterious PTEN variant died. The presence of deleterious PTEN variants [HR = 4.68 [(1.54, 14.27), p = 0.003]] predicted for inferior OS. In the 19 patients with known relapse history, 6/7 (85.7%) with and 3/12 (25%) without any deleterious PTEN mutation relapsed. The presence of deleterious PTEN variants [HR = 9.41 [(2.32, 38.23), p < 0.001]] also predicted for inferior RFS. Conclusions: Pathogenic variants in tumor suppressor PTEN were associated with inferior RFS and OS in this pilot cohort of patients with LS-SCBC, suggesting that disruption of PTEN function may be a critical genomic event underlying the progression of small cell bladder cancer. Our findings also support prior reports that pathogenic gene variants detected at low allele frequencies may be clinically important.

Indomethacin enhances anti-tumor efficacy of a MUC1 peptide vaccine against breast cancer in MUC1 transgenic mice

In recent years, vaccines against tumor antigens have shown potential for combating invasive cancers, including primary tumors and metastatic lesions. This is particularly pertinent for breast cancer, which is the second-leading cause of cancer-related death in women. MUC1 is a glycoprotein that is normally expressed on glandular epithelium, but is overexpressed and under-glycosylated in most human cancers, including the majority of breast cancers. This under-glycosylation exposes the MUC1 protein core on the tumor-associated form of the protein. We have previously shown that a vaccine consisting of MUC1 core peptides stimulates a tumor-specific immune response. However, this immune response is dampened by the immunosuppressive microenvironment within breast tumors. Thus, in the present study, we investigated the effectiveness of MUC1 vaccination in combination with four different drugs that inhibit different components of the COX pathway: indomethacin (COX-1 and COX-2 inhibitor), celecoxib (COX-2 inhibitor), 1-methyl tryptophan (indoleamine 2,3 dioxygenase inhibitor), and AH6809 (prostaglandin E₂ receptor antagonist). These treatment regimens were explored for the treatment of orthotopic MUC1-expressing breast tumors in mice transgenic for human MUC1. We found that the combination of vaccine and indomethacin resulted in a significant reduction in tumor burden. Indomethacin did not increase tumor-specific immune responses over vaccine alone, but rather appeared to reduce the proliferation and increase apoptosis of tumor cells, thus rendering them susceptible to immune cell killing.

Evaluation of CYP2C19 Genotype-Guided Voriconazole Prophylaxis After Allogeneic Hematopoietic Cell Transplant

There is a high risk of voriconazole failure in those with subtherapeutic drug concentrations, which is more common in CYP2C19 (cytochrome P450 2C19) rapid/ultrarapid metabolizers (RMs/UMs). We evaluated CYP2C19 genotype-guided voriconazole dosing on drug concentrations and clinical outcomes in adult allogeneic hematopoietic cell transplant recipients. Poor (PMs), intermediate (IMs), and normal metabolizers (NMs) received voriconazole 200 mg twice daily; RMs/UMs received 300 mg twice daily. Steady-state trough concentrations were obtained after 5 days, targeting 1.0-5.5 mg/L. Of 89 evaluable patients, 29% had subtherapeutic concentrations compared with 50% in historical controls (P < 0.001). Zero, 26%, 50%, and 16% of PMs, IMs, NMs, and RMs/UMs were subtherapeutic. Voriconazole success rate was 78% compared with 54% in historical controls (P < 0.001). No patients experienced an invasive fungal infection (IFI). Genotype-guided dosing resulted in $4,700 estimated per patient savings as compared with simulated controls. CYP2C19 genotype-guided voriconazole dosing reduced subtherapeutic drug concentrations and effectively prevented IFIs.

Baseline Hepatic Levels of miR-29b and Claudin are Respectively Associated with the Stage of Fibrosis and HCV RNA in Hepatitis C

We sought to determine if the baseline hepatic levels of miR-122, miR-29b, Claudin, Occludin, Protein Kinase R (PKR) or PKR activator (PRKRA) were correlated with HCV RNA or stage of fibrosis in patients with chronic hepatitis C (CHC). A total of 25 CHC patients (genotype 1) who were treatment naive at the time of sample collection enrolled in this study. By multivariate analysis, CLDN RNA was found as the single independent factor positively correlated with HCV RNA levels (p=0.003), while hepatic miR-29b levels was found as the single independent factor for predicting advanced stage of fibrosis (p=0.028). Conclusion: Our results highlight miR-29b and CLDN as novel predictors of advanced stage of liver fibrosis and baseline HCV RNA in CHC.

Effect of CYP3A4, CYP3A5, and ABCB1 Polymorphisms on Intravenous Tacrolimus Exposure and Adverse Events in Adult Allogeneic Stem Cell Transplant Patients

Pharmacogenetics influences oral tacrolimus exposure; however, little data exist regarding i.v. tacrolimus. We investigated the impact of genetic polymorphisms in CYP3A4, CYP3A5, and ABCB1 on i.v. tacrolimus exposure and toxicity in adult patients receiving an allogeneic hematopoietic stem cell transplant for hematologic malignancies. Germline DNA was extracted from buccal swabs and genotyped for CYP3A4, CYP3A5, and ABCB1 polymorphisms. Continuous i.v. infusion of tacrolimus .03 mg/kg/day was initiated on day +5 post-transplant, and steady-state blood concentrations were measured 4days later. We evaluated the association between phenotypes and prevalence of nontherapeutic target concentrations (below or above 5 to 15 ng/mL) as well as tacrolimus-related toxicities. Of 63 patients, 28.6% achieved the target concentration; 71.4% were >15ng/mL, which was more common in CYP3A4 intermediate/normal metabolizers (compared with rapid) and those with at least 1 ABCB1 C2677T loss-of-function allele (P < .05). ABCB1 C2677T was significantly associated with concentrations >15ng/mL (odds ratio, 6.2; 95% confidence interval, 1.8 to 23.6; P = .004) and tacrolimus-related toxicities (odds ratio, 7.5; 95% confidence interval, 1.6 to 55.2; P = .02). ABCB1 C2677T and CYP3A4 are important determinants of i.v. tacrolimus exposure, whereas ABCB1 C2677T also impacts tacrolimus-related toxicities in stem cell transplants.

Cytokine profiles in acute liver injury-Results from the US Drug-Induced Liver Injury Network (DILIN) and the Acute Liver Failure Study Group

Changes in levels of cytokines and chemokines have been proposed as possible biomarkers of tissue injury, including liver injury due to drugs. Recently, in acute drug-induced liver injury (DILI), we showed that 19 of 27 immune analytes were differentially expressed and that disparate patterns of immune responses were evident. Lower values of serum albumin (< 2.8 g/dL) and lower levels of only four analytes, namely, IL-9, IL-17, PDGF-bb, and RANTES, were highly predictive of early death [accuracy = 96%]. The goals of this study were to assess levels of the same 27 immune analytes in larger numbers of subjects to learn whether the earlier findings would be confirmed in new and larger cohorts of subjects, compared with a new cohort of healthy controls. We studied 127 subjects with acute DILI enrolled into the US DILIN. We also studied 118 subjects with severe acute liver injury of diverse etiologies, enrolled into the ALF SG registry of subjects. Controls comprised 63 de-identified subjects with no history of liver disease and normal liver tests. Analytes associated with poor outcomes [death before 6 months, n = 32 of the total of 232 non-acetaminophen (Apap) subjects], were lower serum albumin [2.6 vs 3.0 g/dL] and RANTES [6,458 vs 8,999 pg/mL] but higher levels of IL-6 [41 vs 18], IL-8 [78 vs 48], and MELD scores [30 vs 24]. Similar patterns were observed for outcome of death/liver transplant within 6 months. A model that included only serum albumin < 2.8 g/dL and RANTES below its median value of 11,349 had 83% (or 81%) accuracy for predicting early death (or early death/liver transplant) in 127 subjects from DILIN. No patterns of serum immune analytes were reflective of the etiologies of acute liver failure, but there were cytokine patterns that predicted prognosis in both acute DILI and ALF.

Profiles of miRNAs in serum in severe acute drug induced liver injury and their prognostic significance

BACKGROUND & AIMS

Drug induced liver injury (DILI) is challenging because of the lack of biomarkers to predict mortality. Our aim was to describe miRNA changes in sera of subjects with acute idiosyncratic DILI and determine if levels of miRNAs were associated with 6 month mortality.

METHODS

Clinical data and sera were collected from subjects enrolled in the Drug Induced Liver Injury Network prospective study. miRNAs were isolated from serum obtained from 78 subjects within 2 weeks of acute DILI and followed up for 6 months or longer. miRNAs were compared to 40 normal controls and 6 month survivors vs non-survivors.

RESULTS

The mean age of the DILI cohort was 48 years, and 55% were female. Eleven (14.1%) subjects died, 10 within 6 months of DILI onset, 5 (45%) liver related. Lower levels of miRNAs-122, -4463 and -4270 were associated with death within 6 months (P<.05). None of the subjects with miRNA-122 greater than the median value died within 6 months for a sensitivity of 100% and specificity of 57%. In subjects with a serum albumin <2.8 g/dL and miR-122<7.89 RFU the sensitivity, specificity, positive and negative predictive values for death within 6 months were 100%, 57%, 38% and 100% respectively.

CONCLUSIONS

Serum miRNA-122 combined with albumin accurately identified subjects who died within 6 months of drug induced liver injury. If confirmed prospectively, miRNA-122 and albumin may be useful in identifying patients at high risk for mortality or liver transplantation.

Novel biomarkers of resistance of pancreatic cancer cells to oncolytic vesicular stomatitis virus

Vesicular stomatitis virus (VSV) based recombinant viruses (such as VSV-ΔM51) are effective oncolytic viruses (OVs) against a majority of pancreatic ductal adenocarcinoma (PDAC) cell lines. However, some PDAC cell lines are highly resistant to VSV-ΔM51. We recently showed that treatment of VSV-resistant PDAC cells with ruxolitinib (JAK1/2 inhibitor) or TPCA-1 (IKK-β inhibitor) breaks their resistance to VSV-ΔM51. Here we compared the global effect of ruxolitinib or TPCA-1 treatment on cellular gene expression in PDAC cell lines highly resistant to VSV-ΔM51. Our study identified a distinct subset of 22 interferon-stimulated genes (ISGs) downregulated by both ruxolitinib and TPCA-1. Further RNA and protein analyses demonstrated that 4 of these genes (MX1, EPSTI1, XAF1, and GBP1) are constitutively co-expressed in VSV-resistant, but not in VSV-permissive PDACs, thus serving as potential biomarkers to predict OV therapy success. Moreover, shRNA-mediated knockdown of one of such ISG, MX1, showed a positive effect on VSV-ΔM51 replication in resistant PDAC cells, suggesting that at least some of the identified ISGs contribute to resistance of PDACs to VSV-ΔM51. As certain oncogene and tumor suppressor gene variants are often associated with increased tropism of OVs to cancer cells, we also analyzed genomic DNA in a set of PDAC cell lines for frequently occurring cancer associated mutations. While no clear correlation was found between such mutations and resistance of PDACs to VSV-ΔM51, the analysis generated valuable genotypic data for future studies.

Liquid jet delivery method featuring S100A1 gene therapy in the rodent model following acute myocardial infarction

The S100A1 gene is a promising target enhancing contractility and survival post myocardial infarction (MI). Achieving sufficient gene delivery within safety limits is a major translational problem. This proof of concept study evaluates viral-mediated S100A1 overexpression featuring a novel liquid jet delivery (LJ) method. 24 rats after successful MI were divided into 3 groups (n=8 ea.): saline control (SA), ssAAV9.S100A1 (SS) delivery, and scAAV9.S100A1 (SC) delivery (both 1.2×10¹¹ viral particles). For each post MI rat, the LJ device fired three separate 100 μL injections into the myocardium. Following 10 weeks, all rats were evaluated with echocardiography, quantitative polymerase chain reaction (qPCR), and overall S100A1 and CD38 immune protein. At 10 weeks all groups demonstrated a functional decline from baseline, but the S100A1 therapy groups displayed preserved LV function with significantly higher ejection fraction %; SS group [60±3] and SC group [57±4] versus saline [46±3], p<0.05. Heart qPCR testing showed robust S100A1 in the SS [10,147±3993] and SC [35,155±5808] copies per 100 ng DNA, while off target liver detection was lower in both SS [40±40], SC [34,841±3164] respectively. Cardiac S100A1 protein expression was [4.3±0.2] and [6.1±0.3] fold higher than controls in the SS and SC groups respectively, p<0.05.

An unexpected inhibition of antiviral signaling by virus-encoded tumor suppressor p53 in pancreatic cancer cells

Virus-encoded tumor suppressor p53 transgene expression has been successfully used in vesicular stomatitis virus (VSV) and other oncolytic viruses (OVs) to enhance their anticancer activities. However, p53 is also known to inhibit virus replication via enhanced type I interferon (IFN) antiviral responses. To examine whether p53 transgenes enhance antiviral signaling in human pancreatic ductal adenocarcinoma (PDAC) cells, we engineered novel VSV recombinants encoding human p53 or the previously described chimeric p53-CC, which contains the coiled-coil (CC) domain from breakpoint cluster region (BCR) protein and evades the dominant-negative activities of endogenously expressed mutant p53. Contrary to an expected enhancement of antiviral signaling by p53, our global analysis of gene expression in PDAC cells showed that both p53 and p53-CC dramatically inhibited type I IFN responses. Our data suggest that this occurs through p53-mediated inhibition of the NF-κB pathway. Importantly, VSV-encoded p53 or p53-CC did not inhibit antiviral signaling in non-malignant human pancreatic ductal cells, which retained their resistance to all tested VSV recombinants. To the best of our knowledge, this is the first report of p53-mediated inhibition of antiviral signaling, and it suggests that OV-encoded p53 can simultaneously produce anticancer activities while assisting, rather than inhibiting, virus replication in cancer cells.

MiR-122 decreases HCV entry into hepatocytes through binding to the 3' UTR of OCLN mRNA

BACKGROUND & AIMS

Analysis in silico suggests that occludin (OCLN), a key receptor for HCV, is a candidate target of miR-122; the most abundant hepatic micro RNA. We aimed to determine if miR-122 can decrease HCV entry through binding to the 3' UTR of OCLN mRNA.

DESIGN

Huh7.5 cells were cotransfected with luciferase construct containing 3' UTR of OCLN (pLuc-OCLN) and with selected miRNAs (0-50 nM) and luciferase activity was measured. Huh7.5 cells were also infected by viral particles containing lenti-miR122 genome or control virus. After 48 h, the cells were infected with HCV pseudo-particles (HCVpp) and VSV pseudo-particles (VSVpp). After 72 h of infection, luciferase activity was measured and HCVpp activity was normalized to VSVpp activity.

RESULTS

miR-122 binds to the 3'-UTR of OCLN and down-regulates its expression; cotransfection of miR-122 mimic with pLuc-OCLN resulted in a significant decrease in luciferase activity [by 55% (P < 0.01)], while a non-specific miRNA and a mutant miR-122 did not have any effect. miR-122 mimic significantly down-regulated [by 80% (P < 0.01)] OCLN protein in Huh7.5 cells. Accordingly, patients with chronic hepatitis C and higher levels of hepatic miR-122 have lower hepatic expression of OCLN. Immuno-fluorescence imaging showed a decrease in colocalization of OCLN and CLDN following miR-122 over-expression in HCV infected cells. Huh7.5 cells transiently expressing Lenti-miR122 system showed 42% (P < 0.01) decrease in HCV entry.

CONCLUSION

This study uncovers a novel antiviral effect of miR-122 on human liver cells and shows that over-expression of miR-122 can decrease HCV entry into hepatocytes through down-regulation of OCLN.

GSK3β inhibition and LEF1 upregulation in skeletal muscle following a bout of downhill running

Canonical Wnt signaling is important in skeletal muscle repair but has not been well characterized in response to physiological stimuli. The objective of this study was to assess the effect of downhill running (DHR) on components of Wnt signaling. Young, male C57BL/J6 mice were exposed to DHR. Muscle injury and repair (MCadherin) were measured in soleus. Gene and protein expression of Wnt3a, active β-catenin, GSK3β, and LEF1 were measured in gastrocnemius. Muscle injury increased 6 days post-DHR and MCadherin protein increased 5 days post-DHR. Total and active GSK3β protein decreased 3 days (9-fold and 3.6-fold, respectively) post-DHR. LEF1 protein increased 6 days (5-fold) post-DHR. DHR decreased GSK3β and increased LEF1 protein expression, but did not affect other components of Wnt signaling. Due to their applicability, using models of physiological stimuli such as DHR will provide significant insight into cellular mechanisms within muscle.

A novel catechol-O-methyltransferase variant associated with human disc degeneration

BACKGROUND

Disc degeneration and its associated low back pain are a major health care concern causing disability with a prominent role in this country's medical, social and economic structure. Low back pain is devastating and influences the quality of life for millions. Low back pain lifetime prevalence approximates 80% with an estimated direct cost burden of $86 billion per year. Back pain patients incur higher costs, greater health care utilization, and greater work loss than patients without back pain.

METHODS

Research was performed following approval of our Institutional Review Board. DNA was isolated, processed and amplified using routine techniques. Amplified DNA was hybridized to Affymetrix Genome-Wide Human SNP Arrays. Quality control and genotyping analysis were performed using Affymetrix Genotyping Console. The Birdseed v2 algorithm was used for genotyping analysis. 2589 SNPs were selected a priori to enter statistical analysis using lotistic regression in SAS.

RESULTS

Our objective was to search for novel single nucleotide polymorphisms (SNPs) associated with disc degeneration. Four SNPs were found to have a significant relationship to disc degeneration; three are novel. Rs165656, a new SNP found to be associated with disc degeneration, was in catechol-O-methyltransferase (COMT), a gene with well-recognized pain involvement, especially in female subjects (p=0.01). Analysis confirmed the previously association between COMT SNP rs4633 and disc degeneration. We also report two novel disc degeneration-related SNPs (rs2095019 and rs470859) located in intergenic regions upstream to thrombospondin 2.

CONCLUSIONS

Findings contribute to the challenging field of disc degeneration and pain, and are important in light of the high clinical relevance of low back pain and the need for improved understanding of its fundamental basis.

Circadian rhythms in acute intermittent porphyria--a pilot study

BACKGROUND

Acute intermittent porphyria (AIP) is an inherited disorder of haem synthesis wherein a partial deficiency of porphobilinogen (PBG) deaminase (PBGD) with other factors may give rise to biochemical and clinical manifestations of disease. The biochemical hallmarks of active AIP are relative hepatic haem deficiency and uncontrolled up-regulation of hepatic 5-aminolevulinic acid (ALA) synthase-1 (ALAS1) with over-production of ALA and PBG. The treatment of choice is intravenous haem, which restores the deficient regulatory haem pool of the liver and represses ALAS1. Recently, haem has been shown to influence circadian rhythms by controlling their negative feedback loops. We evaluated whether subjects with AIP exhibited an altered circadian profile.

MATERIALS AND METHODS

Over a 21-h period, we measured levels of serum cortisol, melatonin, ALA, PBG and mRNA levels (in peripheral blood mononuclear cells) of selected clock-controlled genes and genes involved in haem synthesis in 10 Caucasian (European-American) women who were either postmenopausal or had been receiving female hormone therapy, six of whom have AIP and four do not and are considered controls.

RESULTS

Four AIP subjects with biochemical activity exhibited higher levels of PBG and lower levels and dampened oscillation of serum cortisol, and a trend for lower levels of serum melatonin, than controls or AIP subjects without biochemical activity. Levels of clock-controlled gene mRNAs showed significant increases over baseline in all subjects at 5 a.m. and 11 p.m., whereas mRNA levels of ALAS1, ALAS2 and PBGD were increased only at 11 p.m. in subjects with active AIP.

CONCLUSIONS

This pilot study provides evidence for disturbances of circadian markers in women with active AIP that may trigger or sustain some common clinical features of AIP.

Cardiac surgical delivery of the sarcoplasmic reticulum calcium ATPase rescues myocytes in ischemic heart failure

BACKGROUND

The sarcoplasmic reticulum calcium ATPase (SERCA2a) is an important molecular regulator of contractile dysfunction in heart failure. Gene transfer of SERCA2a mediated by molecular cardiac surgery with recirculating delivery (MCARD) is a novel and clinically translatable strategy.

METHODS

Ischemic heart failure was induced by ligation of OM1 and OM2 in 14 sheep. Seven sheep underwent MCARD-mediated AAV1-SERCA2a delivery 4 weeks after myocardial infarction, and seven sheep served as untreated controls. Magnetic resonance imaging-based mechanoenergetic studies were performed at baseline, 3 weeks, and 12 weeks after infarction. Myocyte apoptosis was quantified by Tdt-mediated nick-end labeling assay. Myocyte cross-sectional area and caspase-8 and caspase-9 activity was measured with imaging software, specific fluorogenic peptides, and immunohistochemistry.

RESULTS

MCARD-mediated AAV1-SERCA2a gene delivery resulted in robust cardiac-specific SERCA2a expression and stable improvements in global and regional contractility. There were significantly higher stroke volume index, left ventricular fractional thickening, and ejection fraction at 12 weeks in the MCARD group than in the control group (30 ± 3 vs 21 ± 2 mL/m(2); 12% ± 5% vs 3% ± 3%; and 43 ± 4 vs 32 ± 4, respectively, all p < 0.05). Apoptotic myocytes were observed more frequently in the control group than in the MCARD-SERCA2a group (0.57.2 ± 0.16 AU vs 0.32.4 ± 0.08 AU, p < 0.05). MCARD-SERCA2a also resulted in decreased caspase-8 and caspase-9 expression and decreased myocyte area in the border zone of transgenic sheep compared with control sheep (14.6% ± 1.2% vs 2.9% ± 0.7%; 18.2% ± 1.9% vs 8.6% ± 1.4%; and 102.1 ± 3.8 μm(2) vs 88.1 ± 3.6 μm(2), all p < 0.05).

CONCLUSIONS

MCARD-mediated SERCA2a delivery results in robust cardiac specific gene expression, improved contractility, and a decrease in both myocyte apoptosis and myocyte hypertrophy.

Heme status affects human hepatic messenger RNA and microRNA expression

AIM: To assess effects of heme on messenger RNA (mRNA) and microRNA (miRNA) profiles of liver cells derived from humans.

METHODS: We exposed human hepatoma cell line Huh-7 cells to excess iron protoporphyrin (heme) (10 μmol/L) or induced heme deficiency by addition of 4, 6-dioxoheptanoic acid (500 μmol/L), a potent inhibitor of aminolevulinic acid dehydratase, for 6 h or 24 h. We harvested total RNA from the cells and performed both mRNA and miRNA array analyses, with use of Affymetrix chips, reagents, and instruments (human genome U133 plus 2.0 and miRNA 2.0 arrays). We assessed changes and their significance and interrelationships with Target Scan, Pathway Studios, and Ingenuity software.

RESULTS: Changes in mRNA levels were most numerous and striking at 6 h after heme treatment but were similar and still numerous at 24 h. After 6 h of heme exposure, the increase in heme oxygenase 1 gene expression was 60-fold by mRNA and 88-fold by quantitative reverse transcription-polymerase chain reaction. We found striking changes, especially up-regulation by heme of nuclear erythroid-2 related factor-mediated oxidative stress responses, protein ubiquitination, glucocorticoid signaling, P53 signaling, and changes in RNAs that regulate intermediary metabolism. Fewer mRNAs were down-regulated by heme, and the fold decreases were less exuberant than were the increases. Notable decreases after 24 h of heme exposure were patatin-like phospholipase domain-containing protein 3 (-6.5-fold), neuronal PAS domain protein 2 (-1.93-fold), and protoporphyrinogen oxidase (-1.7-fold).

CONCLUSION: Heme excess exhibits several toxic effects on liver and kidney, which deserve study in humans and in animal models of the human porphyrias or other disorders.

Abstract 1573: Early angiogenic switch-associated markers in pancreatic cancer development and progression

Background: There are no warning signs or accurate, noninvasive ways to detect pancreatic cancer (Pc) at early stages. The survival rate at 5 year for patients with Pc is less than 5 percent, and complete remission is rare. Current therapies are inadequate, necessitates development of better diagnostic markers and therapies. Angiogenesis is the process by which tumor cells develop blood supply necessary for their growth and development. Studies have reported an angiogenic switch (AS), a shift of balance occurs between pro-angiogenic and angiogenic state, and is considered a hallmark of cancer progression. Vascular endothelial growth factor (VEGF), the most potent endothelial cell mitogen, is the target for numerous biologic therapies in Pc and other malignancies. We analyzed the expression and sub-cellular localization of VEGF and its receptors1&2, neuropilin (NP-1), matrix mettaloproteinases (MMP) 2 & 9 and epidermal growth factor receptor (EGFR) in pancreatic tumor tissues and serum from 1) a transgenic mouse model of pancreatic ductal adenocarcinoma (PDA) and 2) from a cohort of 80 human Pc patients at various stages of Pc along suitably matched control. Methods: Immunohistochemistry and immunofluorescence staining and quantification of sub-cellular protein expression using ImageJ were performed in tissue samples from PDA mouse and human. Tumor area was distinguished from stroma by tumor “mask,” and sub-cellular locales using DAPI and cytokeratin stains. Scores for the target (i.e. VEGF) were then generated that corresponded to average signal intensity divided by locale area. ELISA and bio-plex cytokine arrays were performed to analyze the serum samples. Statistical analyses were performed using SAS version 9.2. Results: VEGF and other proteins were stained predominantly in the membrane / cytoplasm compartment of malignant epithelium and were over expressed in tumors versus adjacent stroma. Normal epithelium showed lower expression. MMPs specifically MMP-9 showed higher expression at earlier stages of Pc development whereas others showed consistent positive correlation with progression of disease. Using total expression within the tumor, high expressers consistently correlated with worse outcomes and decreased overall survival. These data have been confirmed by serum analyses. Conclusions: VEGF, NP-1, MMP 2 & 9, and EGFR were expressed at varying degrees in Pc and were higher in tumors versus stroma. Higher expression of MMP 2 & 9 showed correlation with earlier stage of Pc development. Further studies of the functional significance of these findings are warranted. The prognostic value of these candidate biomarkers within the tumor microenvironment may facilitate the development of a much needed early stage biomarker and a potential therapeutic target for Pc.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1573. doi:10.1158/1538-7445.AM2011-1573

Legalon-SIL downregulates HCV core and NS5A in human hepatocytes expressing full-length HCV

AIM: To determine the effect of Legalon-SIL (LS) on hepatitis C virus (HCV) core and NS5A expression and on heme oxygenase-1 (HMOX-1) and its transcriptional regulators in human hepatoma cells expressing full length HCV genotype 1b.

METHODS: CON1 cells were treated with 50 μmol/L or 200 μmol/L LS. Cells were harvested after 2, 6 and 24 h. HCV RNA and protein levels were determined by quantitative real-time polymerase chain reaction and Western blotting, respectively.

RESULTS: HCV RNA (core and NS5A regions) was decreased after 6 h with LS 200 μmol/L (P < 0.05). Both 50 and 200 μmol/L LS decreased HCV RNA levels [core region (by 55% and 88%, respectively) and NS5A region (by 62% and 87%, respectively) after 24 h compared with vehicle (dimethyl sulphoxide) control (P < 0.01). Similarly HCV core and NS5A protein were decreased (by 85%, P < 0.01 and by 65%, P < 0.05, respectively) by LS 200 μmol/L. Bach1 and HMOX-1 RNA were also downregulated by LS treatment (P < 0.01), while Nrf2 protein was increased (P < 0.05).

CONCLUSION: Our results demonstrate that treatment with LS downregulates HCV core and NS5A expression in CON1 cells which express full length HCV genotype 1b, and suggests that LS may prove to be a valuable alternative or adjunctive therapy for the treatment of HCV infection.

Meiotic spindle checkpoints for assessment of aneuploid oocytes

The spindle assembly checkpoint suspends cell cycle progression if improperly aligned chromosomes are detected at metaphase. Evolutionarily conserved kinetochore-associated proteins are believed to be key elements of this regulatory pathway. A breakdown in checkpoint function could bring about genomic instability, which may be responsible for the prevalence of aneuploidy in oocytes of older women. Maternal aging remains the overwhelming factor in the etiology of human aneuploidy in assisted reproduction. Defects in cell cycle checkpoint genes may play a role in its development. The existence of such monitoring mechanisms in oocytes has long been controversial. Studies providing evidence in support of and against their existence are reviewed.

Self-correction of chromosomally abnormal embryos in culture and implications for stem cell production

OBJECTIVE

To ascertain whether embryos classified by preimplantation genetic diagnosis (PGD) for infertility as abnormal and then plated to obtain stem cells would self-correct partially or totally in culture, producing disomic stem cells.

DESIGN

Prospective study to determine the chromosome status of embryos on day 3 and 6, as well as cultured cells derived from inner cell masses from the same embryos when cultured up to day 12.

SETTING

Research laboratory.

PATIENT(S)

Patients undergoing PGD of aneuploidy.

INTERVENTION(S)

Of 142 embryos classified by PGD for aneuploidy as abnormal, 50 were cultured to the blastocyst stage. At that stage a fraction of the embryos underwent trophectoderm biopsy to reconfirm the PGD diagnosis. After further co-culture with feeders up to day 12, 34 embryos attached to the feeder cells. Of those, 24 were analyzed by fluorescence in situ hybridization (FISH) and the rest for the expression of Oct-4, SSEA-3, SSEA-4, TRA1-60, and TRA1-80.

MAIN OUTCOME MEASURE(S)

Disomic cells obtained from trisomic embryos.

RESULT(S)

Analysis by FISH of day-12 cultures showed that 7 were totally normal, 6 were mostly abnormal, and 11 had experienced some chromosome normalization, having between 21% and 88% normal cells. Day-12 culture was positive for Oct-4 expression by reverse transcriptase polymerase chain reaction analysis and for SSEA-3, SSEA-4, TRA1-60, and TRA1-80 by immunocytochemistry.

CONCLUSION(S)

Chromosome self-normalization occurs in a significant proportion of chromosomally abnormal embryos, possibly because of the loss of a chromosome in trisomic cells after blastocyst stage. Thus chromosomally abnormal embryos are a potential source of disomic stem cells. Not all chromosomally abnormal embryos self-corrected. Abnormal stem cells that might be derived could be used as models to study the effect of chromosomal abnormalities on human development.

Association of abnormal morphology and altered gene expression in human preimplantation embryos

OBJECTIVE

We set out to characterize the expression of nine genes in human preimplantation embryos and determine whether abnormal morphology is associated with altered gene activity.

DESIGN

Reverse transcription and real-time polymerase chain reaction were used to quantify the expression of multiple genes in each embryo. The genes studied have various important cellular roles (e.g., cell cycle regulation, DNA repair, and apoptosis).

SETTING

Research laboratory working closely with a clinical IVF practice.

PATIENT(S)

Over 50 embryos were donated by infertile patients (various etiologies). Among these, all major stages of preimplantation development and a variety of common morphologic abnormalities were represented.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Quantification of mRNA transcripts.

RESULT(S)

We detected an association between certain forms of abnormal morphology and disturbances of gene activity. Cellular fragmentation was associated with altered expression of several genes, including TP53, suggesting that fragmenting blastomeres are suffering stress of a type monitored by p53, possibly as a consequence of suboptimal culture conditions.

CONCLUSION(S)

Appropriate gene expression is vital for the regulation of metabolic pathways and key developmental events. Our data indicates a possible causal relationship between changes in gene expression and the formation of clinically relevant abnormal embryo morphologies. We hypothesize that embryos with expression profiles characteristic of good morphology and appropriate for their developmental stage have the greatest potential for implantation. If confirmed, this could lead to a new generation of preimplantation genetic diagnosis (PGD) tests for assessing embryo viability and predicting implantation potential.

Expression of genes regulating chromosome segregation, the cell cycle and apoptosis during human preimplantation development

BACKGROUND

Appropriate gene expression is vital for the regulation of developmental processes. Despite this fact there is a remarkable paucity of information concerning gene activity during preimplantation development.

METHODS

We employed reverse transcription and real-time fluorescent PCR to quantify the expression of nine genes (BRCA1, BRCA2, ATM, TP53, RB1, MAD2, BUB1, APC and beta-actin) in oocytes and embryos. A full characterization of all genes was achieved in 42 embryos and four oocytes. The genes analysed have a variety of important cellular functions.

RESULTS

Oocytes displayed relatively high levels of mRNA transcripts, while 2-3-cell embryos were seen to contain very little mRNA from any of the genes examined. Recovery of expression levels was not seen until the 4-cell stage or later, with the presumptive activation of the embryonic genome. Some genes displayed sharp increases in expression in embryos composed of 4-8 cells, but, for most, maximum expression was not achieved until the blastocyst stage.

CONCLUSIONS

Our data show that it is possible to define characteristic gene expression profiles for each stage of human preimplantation development. The identification of genes active at defined preimplantation phases may provide clues to the cellular pathways utilized at specific stages of development. Expression of genes that function in DNA repair pathways indicate that DNA damage may be common at the cleavage stage. We suggest that specific patterns of gene expression may be indicative of embryo implantation potential.

Nitric oxide synthase production and nitric oxide regulation of preimplantation embryo development

Nitric oxide (NO) production plays an important role in regulating preimplantation embryo development. NO is produced from l-arginine by the enzyme nitric oxide synthase (NOS), which has three isoforms: endothelial (eNOS), neuronal (nNOS), and inducible (iNOS). It has been previously shown that inhibition of NO production by NG-nitro-l-arginine (l-NA) inhibits the development of two-cell embryos to the four-cell stage. However, excess NO also halts embryo development, possibly through the production of free radicals. We hypothesize that multiple NOS isoforms are expressed in order to ensure normal preimplantation embryo development and that, in this process, NO acts through the cGMP pathway. Using reverse transcription-polymerase chain reaction, mRNA for all three NOS isoforms was amplified from two-cell, four-cell, morula, and blastocyst embryos. However, blastocyst-stage embryos isolated midmorning on Day 4 of pregnancy expressed only nNOS and eNOS, whereas those isolated midafternoon again expressed all three NOS isoforms. Culture of one-cell embryos in various concentrations of Whitten (positive control), S-nitroso-N-acetylpenicillamine (SNP, a NO donor), l-NA, and/or 8-Br-cGMP demonstrated that NO is acting, at least in part, through cGMP in preimplantation embryo development. In addition, we determined that a critical concentration of NO and cGMP is required for normal embryo development and deviations from this concentration lead to developmental arrest and/or apoptosis of the embryo. This data provides support for a requirement of NO in preimplantation embryo development and one mechanism through which it regulates mitotic division in these embryos.

Quantification of human ooplasmic mitochondria

It is likely that there is an association between the fitness of mitochondria and their ability to support normal cellular function. Oocytes are greatly enriched in the number of mitochondria as they support essential developmental processes such as oocyte maturation and embryonic development, while their replication is deferred until gastrulation. The mitochondrial DNA (mtDNA) copy number in 87 human oocytes from 29 patients was evaluated after DNA extraction and real-time quantitative polymerase chain reaction (PCR). The average mtDNA copy number was 795,000 (+/- 243,000) in metaphase II oocytes. mtDNA content varied considerably between oocytes, even within the same patient. No relationship was found between mtDNA copy number and maternal age. The findings suggest that mtDNA replication is fully accomplished by the germinal vesicle stage in the fully developed oocyte.

Association between spindle assembly checkpoint expression and maternal age in human oocytes

The spindle assembly checkpoint modulates the timing of anaphase initiation in response to the improper alignment of chromosomes at the metaphase plate. If defects are detected, a signal is transduced to halt further progression of the cell cycle until correct bipolar attachment to the spindle is achieved. The mitotic arrest deficient (MAD2) and budding uninhibited by benomyl (BUB1) genes encode conserved kinetochore-associated proteins believed to be components of the checkpoint regulatory pathway. A failure in this surveillance system could lead to genomic instability that may underlie the increased incidence of aneuploidy in the gametes of older women. To explore this possibility, the concentrations of these transcripts in human oocytes at various stages of maturation were determined by real-time rapid cycle fluorescent reverse transcription-polymerase chain reaction (RT-PCR). The results obtained following quantitative analysis suggest that these messages degrade as oocytes age. Potentially, this may impair checkpoint function in older oocytes and may be a contributing factor in age-related aneuploidy.

Quantification of mtDNA in single oocytes, polar bodies and subcellular components by real-time rapid cycle fluorescence monitored PCR

Oocytes, in general, are greatly enriched in mitochondria to support higher rates of macromolecular synthesis and critical physiological processes characteristic of early development. An inability of these organelles to amplify and/or to accumulate ATP has been linked to developmental abnormality or arrest. The number of mitochondrial genomes present in mature mouse and human metaphase II oocytes was estimated by fluorescent rapid cycle DNA amplification, which is a highly sensitive technique ideally suited to quantitative mitochondrial DNA (mtDNA) analysis in individual cells. A considerable degree of variability was observed between individual samples. An overall average of 1.59 x 10(5) and 3.14 x 10(5) mtDNA molecules were detected per mouse and human oocyte, respectively. Furthermore, the mtDNA copy number was examined in polar bodies and contrasted with the concentration in their corresponding oocytes. In addition, the density of mtDNA in a cytoplasmic sample was estimated in an attempt to determine the approximate number of mitochondria transferred during clinical cytoplasmic donation procedures as well as to develop a clinical tool for the assessment and selection of oocytes during in vitro fertilisation procedures. However, no correlation was identified between the mtDNA concentration in either polar bodies or cytoplasmic samples and their corresponding oocyte.

Quantification of mRNA in single oocytes and embryos by real-time rapid cycle fluorescence monitored RT-PCR

Deciphering the complex series of regulatory events that occur during early development depends partly on the ability to accurately quantify stage-specific mRNA species. However, the paucity of biological material coupled with the lack of sensitivity and/or reproducibility of the currently available quantitative methods had been severe limitations on single cell analysis. Rapid cycle DNA amplification is a highly sensitive technique for amplification of specific DNA sequences. With the addition of fluorescence probes, it is possible to monitor the log-linear phase of amplification during which the most useful quantitative data is obtained. Unknown concentrations are extrapolated from standards co-amplified producing a standard curve. Furthermore, micro volume capabilities allow for the analysis of minute samples. Consequently, this approach is ideally suited to the needs of the clinical IVF laboratory. Rapid fluorescence monitored cycling was used to examine expression levels of the housekeeping genes beta-actin and hypoxanthine guanine phosphorlbosyltransferase in individual murine/human oocytes and/or embryos. Results obtained compared favourably with those attained by others and followed the predicted temporal patterns of expression. Once informative reproductive molecular markers are identified by micro-array analysis, minimally invasive techniques can be developed to biopsy cytoplasm and/or polar bodies for clinical evaluation using rapid fluorescence monitored reverse transcription-polymerase chain reaction methods.