Abstract P2-06-06: ALU and LINE-1 hypomethylation is associated with HER2+/ER- subtype of breast cancer

The changes in DNA methylation status in cancer cells are characterized by hypermethylation of promoter CpG islands and diffuse hypomethylation of non-coding genomic regions. ALU and long interspersed nucleotide element-1 (LINE-1) are non-coding genomic repetitive sequences and methylation of these elements can be used as a surrogate marker for genomewide methylation status. This study was designed to evaluate the changes of ALU and LINE-1 hypomethylation during breast cancer progression from normal to pre-invasive lesions and invasive breast cancer (IBC), and their relations with characteristics of IBC. We analyzed the methylation status of ALU and LINE-1 in 145 cases of breast samples including normal breast tissue (n = 30), atypical ductal hyperplasia/ flat epithelial atypia (ADH/FEA, n = 30), ductal carcinoma in situ (DCIS, n = 35) and IBC (n = 50), and another set of 129 cases of IBC by pyrosequencing. LINE-1 methylation was significantly decreased from normal to ADH/FEA, while ADH/FEA, DCIS and IBC were not different each other. There was no difference in ALU methylation levels during progression of breast cancer. In IBC, ALU hypomethylation was correlated with negative estrogen receptor (ER) status (p = 0.007) and LINE-1 hypomethylation was associated with negative ER status (p<0.001), positive HER2 status (p = 0.005) and p53 overexpression (p = 0.024). ALU-1 and LINE-1 methylation status was significantly different between breast cancer subtype and the HER2+/ER- subtype had significantly lower methylation levels and frequencies than the other subtypes. Our findings suggest that LINE-1 hypomethylation is an early event during breast cancer progression and prominent hypomethylation of ALU and LINE-1 in HER2+/ER- subtype may be related to chromosomal instability of this specific subtype.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-06-06.

Causes of death in HIV-infected patients from the Cologne-Bonn cohort

PURPOSE

Causes of death in human immunodeficiency virus (HIV)-infected subjects have changed in countries with high resources over the last several years. Acquired immunodeficiency syndrome (AIDS)-related diseases have become less prevalent, whereas deaths due to non-AIDS causes are increasing. The aim of the present study was to analyse causes of death in the Cologne-Bonn cohort.

METHODS

Causes of death from the Cologne-Bonn cohort between 2004 and 2010 were systematically recorded using the CoDe algorithm (The Coding Causes of Death in HIV Project).

RESULTS

In 3,165 patients followed from 2004 to 2010, 182 deaths occurred (5.7 %, 153 males, 29 females). The median age at the time of death was 47 years (range 24-85 years). The most frequent causes of death were AIDS-defining events (n = 60, 33 %), with non-Hodgkin lymphoma (NHL) (n = 29, 16 %) and infections (n = 20, 11 %) being the leading entities in this category. Non-AIDS malignancies accounted for 16 % (n = 29), non-HIV-related infections for 10 % (n = 18), cardiovascular diseases for 7 % (n = 14), suicide or accident for 4 % (n = 7) and liver diseases for 3 % (n = 5) of deaths (unknown n = 47, 26 %). Although the majority of patients (92.5 %) was on antiretroviral therapy (ART), only 50 % were virologically suppressed (HIV-RNA <50 copies/mL) and 44 % had a decreased CD4+ count (<200/μL) at their last visit before death.

CONCLUSION

One-third of the causes of death in our cohort between 2004 and 2010 was AIDS-related. Since most of these deaths occur with severe immune suppression, they can possibly be prevented by the early diagnosis and treatment of HIV infection. Care providers must be aware of an increased risk for a broad range of diseases in HIV-infected patients and should apply appropriate preventive measures.

Evaluation of an infectious disease consultation programme in a German tertiary care hospital

PURPOSE

To evaluate a newly implemented infectious disease (ID) consultation service in terms of patient care, outcome and antibiotic prescription and to describe factors influencing adherence to recommendations.

METHODS

Data from consultations during the first 6 months of the ID consultation program were collected and evaluated. Consultation requests, diagnostic results, treatment outcomes and antibiotic recommendations were categorised. Diagnostic and therapeutic recommendations were assessed and rated for adherence and outcome. Statistical analysis was performed to identify factors influencing adherence and treatment outcome.

RESULTS

A total of 251 consultations were assessed. In most cases, ID specialists were asked for further advice regarding a previously initiated anti-infective treatment (N = 131, 52 %). In 54 of 195 (28 %) first consultations, the ID specialist proposed a differential diagnosis that differed from that of the working diagnoses submitted with the consultation request, and which was subsequently confirmed in 80 % of these cases. Diagnostic and therapeutic recommendations were made in 190 (76 %) and 240 (96 %) of the consultations, respectively. A change in the current treatment was recommended in 66 % of consultations; 37 % of recommendations were cost-saving and 26 % were cost-neutral. Compliance with diagnostic and therapeutic recommendations was rated as good by pre-specified criteria in 65 and 86 % of consultations, respectively. Treatment outcome was correlated with adherence to diagnostic recommendations (P = 0.012). Twenty-nine patients (16 %) died during the same hospital stay.

CONCLUSION

Infectious disease consultations may help to establish the correct diagnosis, resulting in the appropriate treatment being provided to a severely sick patient population. Treatment outcome was improved in cases of good diagnostic adherence to the recommendations of the ID specialist.

Organic cation transporters OCT1 and OCT2 determine the accumulation of lamivudine in CD4 cells of HIV-infected patients

PURPOSE

Identifying factors that determine concentrations of antiretroviral drugs in CD4 cells are important for improving therapeutic efficacy. Experimental models indicate that the nucleoside reverse transcriptase inhibitor lamivudine is transported by the organic cation transporters 1 and 2 (OCT1 and OCT2, respectively). Here, we tested whether OCT1 and OCT2 contribute to the uptake of lamivudine into native CD4 cells of human immunodeficiency virus (HIV)-infected individuals.

METHODS

CD4 cells obtained by non-activated cell sorting from 35 individuals with HIV-1 infection were incubated with lamivudine (10 μM, 30 min), and intracellular concentrations of lamivudine and its active metabolite lamivudine triphosphate were determined by liquid chromatography tandem mass spectrometry. The expression of OCT1 and OCT2 mRNA was measured by quantitative real-time polymerase chain reaction (PCR). A model of OCT2-transfected CD4 cells was established for mechanistic investigations.

RESULTS

Intracellular concentrations of lamivudine and its active metabolite lamivudine triphosphate showed strong linear correlations with each other and with the CD4 mRNA expression of OCT1 and OCT2 (r > 0.80). Coincubation with protease inhibitors (ritonavir, nelfinavir) that inhibit OCT1 and OCT2 yielded decreased intracellular concentrations of lamivudine and lamivudine triphosphate. Incubation of CD4 cells from healthy donors transfected with an OCT2 expression vector yielded increased concentrations of lamivudine and lamivudine triphosphate.

CONCLUSION

Our studies indicate a role of OCT1 and OCT2 for the cellular accumulation of lamivudine in HIV-infected individuals.

Liver involvement in HIV-infected patients diagnosed with syphilis

PURPOSE

Liver involvement in syphilis has been studied in cohorts of human immunodeficiency virus (HIV)-negative individuals despite the scarcity of data on such HIV-infected patients. Th aim of this study was to assess hepatic involvement of HIV-infected patients diagnosed with syphilis.

METHODS

Patients with syphilis and liver involvement, including all stages of syphilis, were systematically identified in our HIV cohort between 2004 and 2008.

RESULTS

Of the 1,599 HIV-infected patients identified during the study period, 100 were diagnosed with acute syphilis, all of whom were male. Of these 100 patients, 84% were men who have sex with men. Laboratory parameters of liver involvement were present in 19 of the 100 HIV-infected patients with syphilis; these resolved after successful antibiotic treatment. Among these 19 patients, six were diagnosed to be in the latent stage, with elevated liver enzymes and parameters of inflammation representing the only distinctive feature.

CONCLUSIONS

Based on our results, syphilis should be included in the differential diagnosis of increased liver enzymes in HIV-infected patients.

Long-term beneficial effect of protease inhibitors on the intrinsic apoptosis of peripheral blood mononuclear cells in HIV-infected patients

BACKGROUND

Viral suppression by antiretroviral therapy (ART) inhibits HIV-induced apoptosis and CD4 T-cell loss. It has been suggested that protease inhibitors (PIs) have nonviral antiapoptotic effects by maintaining mitochondrial integrity. Long-term clinical effects of PI-based ART on mitochondrial toxicity and lymphocyte apoptosis beyond viral suppression have not been exploited to date.

METHODS

We conducted a 7-year study on HIV-1-infected patients from the Cologne HIV cohort with sufficient viral suppression under either a PI-based or nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen. Eight patients on PI and eight on NNRTI were eligible for inclusion in the analysis. The primary outcome measure was defined as a change in the mitochondrial-to-nuclear DNA ratio in PBMCs. Further key molecules involved in extrinsic [tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), Fas ligand (FasL) and caspase 8], intrinsic [B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), caspase 9 and lactate-to-pyruvate ratio] and overall apoptosis [Annexin+/7-aminoactinomycin D (7-AAD)- and caspase 3/7] and viral activity [negative regulatory factor (Nef), interferon-α (IFN-α) and myxovirus resistance protein A (MxA)] were measured.

RESULTS

Demographic and baseline clinical parameters were similar in the two groups, except that patients in the PI group had a higher mean age. After 7 years of treatment, CD4 T-cell count increased and the expression of genes encoding the proapoptotic viral protein Nef and HIV-induced cytokine IFN-α and its downstream effector MxA decreased in both groups. Focusing on the different pathways of apoptosis, only in the PI group intrinsic apoptosis decreased significant and in the inter-group comparison the decrease was significantly higher than in the NNRTI group.

CONCLUSIONS

Our study provides evidence that long-term therapy with a PI-based regimen may be superior to that with a NNRTI-based regimen with regard to its intrinsic antiapoptotic effect.

P1-05-04: Distinct Patterns of Promoter CpG Island Methylation of Breast Cancer Subtype Are Associated with Different Stem Cell Phenotype

Background: Although DNA methylation profiles in breast cancer have been connected to breast cancer molecular subtype, there have been no studies of the association of DNA methylation with stem cell phenotype. This study was designed to evaluate promoter CpG islands methylation of 15 genes with regard to breast cancer subtype and to investigate whether the patterns of CpG island methylation in each subtype are associated with cancer stem cell phenotype represented by CD44+/CD24- or ALDH1 expression.

Methods: We performed MethyLight analysis for the methylation status of 15 promoter CpG island loci involved in breast cancer progression (APC, DLEC1, GRIN2B, GSTP1, HOXA1, HOXA10, IGF2, MT1G, RARB, RASSF1A, RUNX3, SCGB3A1, SFRP1, SFRP4, and TMEFF2) and determined cancer stem cell phenotype by CD44/CD24 and ALDH1 immunohistochmeistry in 36 luminal A, 33 luminal B, 30 luminal-HER2, 40 HER2 enriched, and 40 basal-like subtypes of breast cancer.

Results: The number of CpG island loci methylated was significantly different among subtypes and it was highest in luminal-HER2 subtype and lowest in basal-like subtype. Methylation frequencies and levels in 12 out of the 15 genes were significantly different among all subtypes and basal-like subtype showed significantly lower methylation frequencies and levels in nine genes, compared to luminal A, luminal B, HER2 enriched, and luminal-HER2 subtypes. CD44+/CD24- or ALDH1+ putative stem cell populations were most enriched in basal-like subtype. The methylation of promoter CpG islands was significantly lower in CD44+/CD24-cell (+) tumors, compared to CD44+/CD24-cell (−) tumors, even within the basal-like subtype. ALDH1 (+) tumors also had significantly lower methylation, compared to ALDH1 (−) tumors.

Conclusions: Our findings showed that promoter CpG island methylation was significantly different according to breast cancer subtype and stem cell phenotype of tumor, suggesting that breast cancers have different methylation patterns according to molecular subtypes and it is associated with stem cell phenotypes of the tumor.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-05-04.

[HIV infection: a chronic disease with new challenges]

The treatment of cardiovascular, metabolic and malignant diseases is playing an increasing role in HIV-infected patients. Intensified cancer screening is recommended, but data demonstrating a reduction of tumour incidence or tumour-associated mortality are rare. Controversy exists about the best time point of initiation of antiretroviral therapy. Recently, data indicate that an earlier start could reduce HIV transmission.

Intrapericardial procedures for cardiac regeneration by stem cells: need for minimal invasive access (AttachLifter) to the normal pericardial cavity

In view of the only modest functional and anatomical improvements achieved by bone marrow-derived cell transplantation in patients with heart disease, the question was addressed whether the intracoronary, transcoronary-venous, and intramyocardial delivery routes are adequate. It is hypothesized that an intrapericardial delivery of stem cells or activators of resident cardiac stem cells increases therapeutic benefits. From such an intrapericardial depot, cells or modulating factors, such as thymosin β4 or Ac-SDKP, are expected to reach the myocardium with sustained kinetics. Novel tools which provide access to the pericardial space even in the absence of pericardial effusion are, therefore, described. When the pericardium becomes attached to the suction head (monitored by an increase in negative pressure), the pericardium is lifted from the epicardium ("AttachLifter"). The opening of the suction head ("Attacher") is narrowed by flexible clamps which grab the tissue and improve the vacuum seal in the case of uneven tissue. A ridge, i.e.,"needle guidance", on the suction head excludes injury to the epicardium, whereby the pericardium is punctured by a needle which resides outside the suction head. A fiberscope can be used to inspect the pericardium prior to puncture. Based on these procedures, the role of the pericardial space and the presence of pericardial effusion in cardiac regeneration can be assessed.

Epigenetic memory in induced pluripotent stem cells

Somatic cell nuclear transfer and transcription-factor-based reprogramming revert adult cells to an embryonic state, and yield pluripotent stem cells that can generate all tissues. Through different mechanisms and kinetics, these two reprogramming methods reset genomic methylation, an epigenetic modification of DNA that influences gene expression, leading us to hypothesize that the resulting pluripotent stem cells might have different properties. Here we observe that low-passage induced pluripotent stem cells (iPSCs) derived by factor-based reprogramming of adult murine tissues harbour residual DNA methylation signatures characteristic of their somatic tissue of origin, which favours their differentiation along lineages related to the donor cell, while restricting alternative cell fates. Such an 'epigenetic memory' of the donor tissue could be reset by differentiation and serial reprogramming, or by treatment of iPSCs with chromatin-modifying drugs. In contrast, the differentiation and methylation of nuclear-transfer-derived pluripotent stem cells were more similar to classical embryonic stem cells than were iPSCs. Our data indicate that nuclear transfer is more effective at establishing the ground state of pluripotency than factor-based reprogramming, which can leave an epigenetic memory of the tissue of origin that may influence efforts at directed differentiation for applications in disease modelling or treatment.

Preferential upregulation of interferon-alpha subtype 2 expression in HIV-1 patients

Humans tailor virus-specific immune responses through modulated expression of 12 different interferon (IFN)-alpha subtypes. However, exacerbated expression of certain IFN-alpha subtypes causes immunopathology in the context of autoimmune conditions and chronic viral infections. We showed that progression to AIDS is associated with elevated expression of IFN-alpha in unstimulated peripheral blood mononuclear cells. Here, we sought to determine whether distinct IFN-alpha subtypes are involved in this phenomenon. We used quantitative RT-PCR to assess expression levels of 12 IFN-alpha subtypes in peripheral blood mononuclear cells from normal donors and HIV-1 patients at CDC stage A and stage C of the disease. Three patterns of IFN-alpha subtype expression emerged. First, IFN-alpha2 and IFN-alpha6 mRNA levels were elevated in both patient groups. Second, IFN-alpha1/13, IFN-alpha8, IFN-alpha14, IFN-alpha16, IFN-alpha17, and IFN-alpha21 were upregulated in stage C but not stage A patients. Third, expression levels of IFN-alpha4, IFN-alpha5, IFN-alpha7, and IFN-alpha10 did not change among the three groups of volunteers. Among all other subtypes, IFN-alpha2 was preferentially upregulated, showing >60-fold higher levels in stage A and >400-fold in stage C patients compared with controls, which correlated with declining CD4 counts. Our results demonstrate that distinct IFN-alpha subtypes are sequentially activated during HIV-1 infection, which may be predictive of disease progression.