Time spent in target range assessed by self-monitoring blood glucose associates with glycated hemoglobin in insulin treated patients with diabetes

BACKGROUND AND AIMS

Self-monitoring blood glucose (SMBG) remains a widespread tool to monitor blood glucose. The development of diabetes management systems (DMS) allows SMBG to provide additional information as time spent in target range (TIR). This study evaluates the association between HbA1c and TIR, evaluated through DMS, over 2 months, and 2 weeks.

METHODS AND RESULTS

Type 1 (T1D) and Type 2 (T2D) insulin-treated patients with diabetes were enrolled. We used the term PIR (Points in Range) instead of TIR, since SMBG provides point-in-time glucose values rather than a continuous trend over time. PIR was calculated in 2-month and 2-week time ranges before available HbA1c measurement. One-hundred ninety-seven patients with T1D and 36 with T2D were recruited. HbA1c and PIR were inversely associated (2 months: R -0.72, 2 weeks R -0.70; p < 0.0001) in all subjects. The relationship did not change when T1D and T2D patients were analyzed separately. For every 10% change of PIR, there was a change of HbA1c by 0.4%.

CONCLUSIONS

Our study, for the first time, demonstrates a significant correlation between HbA1c and PIR calculated by DMS. DMS offers additional information useful in disease management of patients with T1D and T2D performing SMBG.

Abstract 4257: Genome-wide CpG island methylation analysis identifies tumor specifically methylated genes in non-small cell lung cancer patients

DNA methylation is part of the epigenetic gene regulation complex and it has been shown that methylation of certain genes occurs frequently in non-small cell lung cancers (NSCLC). We performed a genome-wide search for methylated CpG islands in primary tumors and corresponding non-malignant lung tissue samples of 101 stage I-III NSCLC patients by combining methylated DNA immunoprecipitation and microarray analysis using NimbleGen's 385K Human CpG Island plus Promoter arrays (MeDIP-chip). To test for differences in methylation between tumors and corresponding non-malignant lung tissues, we calculated paired t-statistics with permutation adjusted p-values for step down multiple testing. Overall, we identified 2.414 genomic positions differentially methylated between tumor and corresponding non-malignant lung tissue samples by MeDIP-chip analyses. Ninety-seven % of them were found to be tumor-specifically methylated. Annotation of these genomic positions resulted in the identification of 477 tumor-specifically methylated genes. These genes were classified according to Gene Ontology (GO) categories and over-representation of certain GO terms was calculated. Interestingly, we found that a large number of tumor-specifically methylated genes act as regulators of gene expression or mediate homophilic cell adhesion. Tumor-specific methylation of selected genes was confirmed by methylation-sensitive high-resolution melting analysis and ROC curve analyses revealed that primary tumors may be distinguished from non-malignant lung tissue samples by methylation of certain genes. In addition, in the majority of tumors methylation of certain genes was associated with loss of their protein expression determined by immunohistochemistry. Moreover, treatment of NSCLC cells with epigenetically active drugs resulted in upregulated expression of many tumor-specifically methylated genes analysed by gene expression microarrays. In conclusion, we identified a large number of tumor-specifically methylated genes in NSCLC patients. Expression of many of them is regulated by methylation. Overall, our findings emphasize the impact of methylation on the pathogenesis of NSCLCs.

Citation Format: Gerwin Heller, Valerie Babinsky, Barbara Ziegler, Marlene Weinzierl, Christian Noll, Corinna Altenberger, Leonhard Muellauer, Gerhard Dekan, Yuliya Grin, Gyoergy Lang, Adelheid End-Pfützenreuter, Irene Steiner, Sonja Zehetmayer, Balazs Doeme, Madeleine Arns, Kwun M. Fong, Casey M. Wright, Ian A. Yang, Walter Klepetko, Martin Posch, Christoph C. Zielinski, Sabine Zoechbauer-Mueller. Genome-wide CpG island methylation analysis identifies tumor specifically methylated genes in non-small cell lung cancer patients. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4257. doi:10.1158/1538-7445.AM2013-4257

Genome-wide miRNA expression profiling identifies miR-9-3 and miR-193a as targets for DNA methylation in non-small cell lung cancers

PURPOSE

The major aim of this study was to investigate the role of DNA methylation (referred to as methylation) on miRNA silencing in non-small cell lung cancers (NSCLC).

EXPERIMENTAL DESIGN

We conducted microarray expression analyses of 856 miRNAs in NSCLC A549 cells before and after treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (Aza-dC) and with a combination of Aza-dC and the histone deacetylase inhibitor trichostatin A. miRNA methylation was determined in 11 NSCLC cell lines and in primary tumors and corresponding nonmalignant lung tissue samples of 101 patients with stage I-III NSCLC.

RESULTS

By comparing microarray data of untreated and drug-treated A549 cells, we identified 33 miRNAs whose expression was upregulated after drug treatment and which are associated with a CpG island. Thirty (91%) of these miRNAs were found to be methylated in at least 1 of 11 NSCLC cell lines analyzed. Moreover, miR-9-3 and miR-193a were found to be tumor specifically methylated in patients with NSCLC. We observed a shorter disease-free survival of patients with miR-9-3 methylated lung squamous cell carcinoma (LSCC) than patients with miR-9-3 unmethylated LSCC by multivariate analysis [HR = 3.8; 95% confidence interval (CI), 1.3-11.2, P = 0.017] and a shorter overall survival of patients with miR-9-3 methylated LSCC than patients with miR-9-3 unmethylated LSCC by univariate analysis (P = 0.013).

CONCLUSIONS

Overall, our results suggest that methylation is an important mechanism for inactivation of certain miRNAs in NSCLCs and that miR-9-3 methylation may serve as a prognostic parameter in patients with LSCC.

Abstract 4828: Genome-wide DNA methylation analysis identifies tumor-specifically methylated genes in non-small cell lung cancer patients

Epigenetic changes largely contribute to the regulation of gene expression in cancer cells. DNA methylation is part of this epigenetic gene regulation complex and it has been shown that methylation of certain genes occurs frequently in non-small cell lung cancers (NSCLC). So far, in primary NSCLCs mainly studies investigating methylation of small numbers of genes have been performed. Thus, we performed a genome-wide search for methylated CpG islands in primary tumors and corresponding non-malignant lung tissue samples of 100 stage I-III NSCLC patients by combining methylated DNA immunoprecipitation (MeDIP) and microarray analysis (MeDIP-chip). 385K Human CpG Island plus Promoter arrays from NimbleGen which cover ∼28,000 CpG islands were used. To test for differences in methylation between tumors and corresponding non-malignant lung tissues we calculated paired t-statistics and performed a multiplicity adjusted permutation test. By this approach we identified 303 tumor-specifically methylated genes. These genes include 263 well characterized protein encoding genes and 40 predicted genes. Tumor-specifically methylated genes were classified according to Gene Ontology (GO) categories and over-representation of certain GO terms was calculated. This analysis demonstrated that a large number of tumor-specifically methylated genes act as regulators of gene expression (including members of homeobox, forkhead box and paired box gene clusters) or mediate homophilic cell adhesion (including members of protocadherin alpha and gamma gene clusters). To confirm our results obtained by MeDIP-chip analysis we additionally performed methylation-sensitive high-resolution melting (MS-HRM) analysis of selected genes (e.g. HOXA2, SHOX2 and TAL1). These results corresponded with the results obtained by MeDIP-chip analysis. A comparison of our methylation results obtained by MeDIP-chip analysis and clinico-pathological characteristics of the patients will be performed. In conclusion, using a genome-wide approach we identified a large number of tumor-specifically methylated genes in NSCLC patients. From many of these genes epigenetic regulation was unknown so far. Moreover, our data suggest that transcriptional regulation and cell adhesion are frequently affected by DNA methylation in NSCLC. Overall, our results stress the importance of DNA methylation for the pathogenesis of NSCLC.

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 4828. doi:10.1158/1538-7445.AM2011-4828

Abstract 177: MicroRNA expression profiling in non-small cell lung cancer cells treated with 5-aza-2′-deoxycytidine and trichostatin A

DNA methylation is, besides other mechanisms like histone modifications, part of the epigenetic gene silencing machinery which leads to inactivation of certain tumor suppressor genes (TSG) in cancer. Numerous TSGs have already been identified which are frequently methylated in lung cancer and transcriptionally silenced. While DNA methylation is reversible by DNA methyltransferase inhibitors like 5-aza-2′-deoxycytidine (Aza-dC), histone deacetylation can be inhibited by histone deacetylase inhibitors like trichostatin A (TSA). Overall, there is a synergistic effect in gene re-expression using both drugs. Recently, it has been observed that also microRNA (miRNA) encoding genes may be targets for methylation in cancer. miRNAs are short, noncoding RNAs which act as post-transcriptional regulators of gene expression and therefore are involved in regulation of various biological processes. So far, about 900 human miRNAs have been identified and it has been suggested that altered expression of certain miRNAs is involved in tumorigenesis. However, information about regulation of expression of miRNA encoding genes is limited so far. To investigate the role of epigenetic miRNA gene silencing in lung cancer, we performed a genome-wide microarray based screen for differentially expressed miRNAs in non-small cell lung cancer A549 cells before and after treatment with Aza-dC or a combination of Aza-dC and TSA. Total RNA from untreated and drug treated cells was size fractionated, Cy3/Cy5 labeled and hybridized to dual-channel microarrays (designed by LC Sciences according to miRBase 12.0 covering 853 miRNAs). Microarray data were normalized and t-statistics were performed to identify miRNAs differentially expressed before and after drug treatment. 28 miRNAs were identified whose expression was up-regulated in Aza-dC treated A549 cells and 32 miRNAs whose expression was up-regulated in Aza-dC/TSA treated cells. Overall, expression of 41 miRNAs was up-regulated after Aza-dC or Aza-dC/TSA treatment of A549 cells. 21 out of these 41 (52%) miRNA genes are associated with a CpG island. Some of these 21 miRNAs (e.g. hsa-let-7a, hsa-miR-27b) were already found to be down-regulated in lung cancer tissue, however, the mechanism of silencing was unknown. The genes encoding for these miRNAs will be further analysed for methylation in additional lung cancer cell lines and in primary lung cancer samples. In conclusion, we identified several miRNA encoding genes whose expression seems to be regulated by epigenetic mechanisms in lung cancer. Overall, our results suggest that epigenetic silencing might be an important mechanism for inactivation of certain miRNA encoding genes in lung cancer.

This work was supported by the Vienna Science and Technology Fund (WWTF, project number LS07-019).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 177.

Genetic structure of autochthonous populations of Meso-America: Mexico

We analyze the possible effect of gene flow on the genetic structure of present-day Mexicans. For this purpose we reviewed previous admixture estimates for various Indian and Mestizo groups. Several facts seem clear: (1) There are no pure Indian groups in Mexico, because all Indian groups show variable degrees of admixture, mostly with whites (range, 0.088 in the Huichol to 0.373 in the Huasteco); (2) the main ancestral contribution to the noncoastal lower middle class Mestizo populations is Indian (above 50%) so that from a genetic standpoint Indians and lower middle class Mestizos are not much different; and (3) black ancestry is quite high on the coasts, ranging from 0.127 to 0.405 on the east coast, and is present in other Mestizos, ranging in large urban centers from 0.027 in Oaxaca to 0.107 in Puebla and in smaller cities from 0.08 in Tlaxcala to 0.181 in Cuanalán.

[Risk for Down syndrome based on maternal ages grouped in intervals of 2 and 5 years in the Mexican population]

Based on the analysis of 515 patients with Down's syndrome, identified in the Mexican program of Registry and Epidemiological Surveillance of External Congenital Malformations, we obtained the risk at birth for this disease, according to the mother's age, grouped in two and five years intervals. The results confirms other studies suggesting that the risk increases after age 30 and particularly 35. For example the incidence in women 21-22 years old is 0.62 per 1000 births and 40.7 in mothers ages 43-44. The data presented can be utilized for genetic counselling in Mexico and we recommend the use of the biannual figures because they are more precise than the usually employed five years intervals results.

Gene frequencies and admixture estimates in four Mexican urban centers

We studied 202 individuals from the city of Leon in Guanajuato state, 228 from Merida, Yucatan, 220 from Oaxaca, Oaxaca, and 257 from Saltillo, Coahuila, to learn the distribution of the ABO, MN, Rh, and Duffy blood groups, serum haptoglobin, albumin, and factor Bf types, and red cell hemoglobin and glucose-6-phosphate dehydrogenase types. With the gene frequencies obtained, we performed admixture measurements with a maximum likelihood method, obtaining a trihybrid model for black, Indian, and white ancestry with the following proportions: 0.084, 0.513, and 0.403 in Leon: 0.059, 0.512, and 0.429 in Merida; 0.018, 0.676, and 0.306 in Oaxaca; and 0.073, 0.547, and 0.380 in Saltillo. The general pattern has high Indian ancestry followed by white and black ancestry. This pattern is congruent with most other studies performed in Mexico, including the east coast, where Indian ancestry predominates despite a clear increase in the black contribution.

[Risk factors associated with neural tube defects: exposure during the first trimester of gestation]

The neural tube defects (NTD) are a group of malformations of multifactorial etiology. Their high incidence in Mexico and the etiologic heterogeneity observed in several studies, prompted the present investigation with the main objective of looking for risk factors associated to NTD. We analyzed maternal exposure during the first trimester of pregnancy to different environmental factors, such as acute or chronic illnesses, immunizations, smoking, alcoholism, maternal or paternal occupation and exposure to chemicals. The sample include 360 patients with anencephaly, 249 with spina bifida and 44 with encephalocele, ascertained from a total of 230 635 live births and 4,020 stillborns, studied in the Mexican program of Registro y Vigilancia Epidemiológica de Malformaciones Congénitas Externa. Of the risk factors considered, significant differences with the control group were found for anencephaly in relation to maternal viral upper respiratory infection, hyperthermia, ingestion of analgesics, antiemetics and paternal occupation. In the case of spina bifida, significant differences were found only for viral upper respiratory infections.

Gene frequencies and admixture estimates in the state of Puebla, Mexico

Three hundred ninety-three individuals from the Universidad Autónoma de Puebla and its University Hospital were studied to determine the distribution of ABO, MN, Rh-Hr, Duffy, and Diego blood groups; red cell hemoglobin and glucose-6-phosphate dehydrogenase variants; and serum haptoglobins, albumins, and factor Bf types. With the results we estimated that the proportions of black, indian, and white genes are 10.7%, 56.3%, and 33.0%, respectively, in a trihybrid model. Reasons are given as to why the black ancestry may be artifically high, and it is pointed out that independent confirmation with other markers is needed before the figure can be accepted as a true value.

Gene frequencies and admixture estimates in a Mexico City population

Five hundred and ten students of the Universidad Nacional Autónoma de México were tested to determine the distribution of ABO, MN, Rr-Hr blood groups, and serum haptoglobin, albumin, and Factor Bf types. Based on the results we found that the proportion of Indian and White genes are of 56.16 and 43.84%, respectively in the dihybrid model and 2.93, 56.22, and 40.85% for Blacks, Indians, and Whites in the trihybrid one. The present study reveals a higher proportion of Indian genes in the Mexico City population than estimated in previous publications. Reasons why the present results apply to a much larger group of Mexico City mestizos than the previous ones are given.

Fetal mortality in sibships with one or more affected members with oral clefts

We investigated the fetal mortality in 903 sibships with at least one member having cleft lip with or without cleft palate [CL(P)] and 213 with at least one individual affected with cleft palate (CP) derived from three different data sources in México. The frequency of fetal wastage (abortion and/or stillbirth) was not increased in sibships where the propositi had cleft lip and palate (CLP) as compared with cleft lip (CL) nor in those where index cases had a bilateral lesion as compared to a unilateral one, nor when the index cases with CL(P) were female rather than males, nor when the index case was a female with bilateral lesion as compared to males with a unilateral one. Similarly fetal mortality was not increased in sibships in which the propositus had CP compared to those in which the index case was a female. These findings are contrary to some reports that claim to support a two-threshold model according to which individuals reaching the first one would be born with an oral cleft, and those reaching the second would be aborted. Our results, together with others, suggest the possibility that liability to oral clefts is independent of liability to fetal wastage.