George Calin

Epigenetic inactivation of miR-9 family microRNAs in chronic lymphocytic leukemia - Implications on constitutive activation of NFκB pathway

BackgroundThe miR-9 family microRNAs have been identified as a tumor suppressor miRNA in cancers. We postulated that miR-9-1, miR-9-2 and miR-9-3 might be inactivated by DNA hypermethylation in chronic lymphocytic leukemia (CLL).MethodsMethylation of miR-9-1, miR-9-2 and miR-9-3 was studied in eight normal controls including normal bone marrow, buffy coat, and CD19-sorted peripheral blood B-cells from healthy individuals, seven CLL cell lines, and seventy-eight diagnostic CLL samples by methylation-specific polymerase chain reaction.ResultsThe promoters of miR-9-3 and miR-9-1 were both unmethylated in normal controls, but methylated in five (71.4%) and one of seven CLL cell lines respectively. However, miR-9-2 promoter was methylated in normal controls including CD19u2009+u2009ve B-cells, hence suggestive of a tissue-specific but not tumor-specific methylation, and thus not further studied. Different MSP statuses of miR-9-3, including complete methylation, partial methylation, and complete unmethylation, were verified by quantitative bisulfite methylation analysis. 5-Aza-2′-deoxycytidine treatment resulted in miR-9-3 promoter demethylation and re-expression of pri-miR-9-3 in I83-E95 and WAC3CD5+ cells, which were homozygously methylated for miR-9-3. Moreover, overexpression of miR-9 led to suppressed cell proliferation and enhanced apoptosis together with downregulation of NFκB1 in I83-E95 cells, supporting a tumor suppressor role of miR-9-3 in CLL. In primary CLL samples, miR-9-3 was detected in 17% and miR-9-1 methylation in none of the patients at diagnosis. Moreover, miR-9-3 methylation was associated with advanced Rai stage (≥ stage 2) (Pu2009=u20090.04).ConclusionsOf the miR-9 family, miR-9-3 is a tumor suppressor miRNA relatively frequently methylated, and hence silenced in CLL; whereas miR-9-1 methylation is rare in CLL. The role of miR-9-3 methylation in the constitutive activation of NFκB signaling pathway in CLL warrants further study.

Novel Biomarkers for Acute Myocardial Infarction: Is MicroRNA the New Kid on the Block?

Early detection of acute myocardial infarction (AMI)9 is crucial for deciding the course of treatment to preserve and prevent further damage to the myocardial tissue. Guidelines from the American College of Cardiology give the criteria for AMI as an increase or decrease in troponin with at least one value >99% percentile of a healthy population (with an imprecision of <10%) accompanied by either symptoms of ischemia or evidence of MI based on imaging or electrocardiography modalities. Over the last several years, creatine kinase MB testing has been replaced by newer generations of troponin assays. High-sensitivity assays are now considered the gold-standard marker for myocardial necrosis. Indeed, the improved analytical sensitivity of high-sensitivity troponin assays has lowered the threshold for myocardial injury, making it easier to detect baseline values in the picogram-per-milliliter range and thus expediting early diagnosis. The gains in diagnostic sensitivity have come at the cost of decreases in diagnostic specificity, however. A major challenge is that high-sensitivity assays quantify troponin in a greater proportion of healthy individuals. These assays also detect myocardial cell death associated with other pathophysiological conditions, such as cardiomyopathies, myocarditis, renal failure, congestive heart failure, and pulmonary embolism, and do not distinguish between mechanisms of tissue injury, thus limiting the ability to differentiate on the basis of MI severity [e.g., ST-segment elevation myocardial infarction (STEMI) vs. non-STEMI]. Consequently, the introduction of high-sensitivity troponin assays into clinical practice has caused confusion for physicians treating patients with acute chest pain. Therefore, the ideal biomarker to rule in and rule out AMI rapidly and reliably is still lacking.nnDuring the last several years, there has been a burgeoning interest in circulating microRNAs (miRNAs) as potential novel biomarkers for AMI. miRNA is a type of single-stranded, noncoding small ribonucleic acid (about 22 nucleotides in length) located within introns …

The emerging role of long noncoding RNAs in oral cancer

Although less than 3% of the genome encodes proteins, at least 75% of the genome is transcribed into RNAs with no protein-coding potential (noncoding RNAs [ncRNAs]). On the basis of their size and the arbitrary 200 nucleotides cutoff, ncRNAs are classified into long ncRNAs (lncRNAs) or small ncRNAs (including microRNAs). Over the last few years, the role of microRNAs in oral squamous cells carcinoma (OSCC) has been extensively addressed, but the possible role of lncRNAs in OSCC remains unclear. We aimed to explore and discuss the potential role of lncRNAs in OSCC. The detection of lncRNAs in saliva holds promise not only as a noninvasive diagnostic tool in OSCC but also in the early detection of oral cancer recurrence. lncRNAs are promising future therapeutic targets in the OSCC scenario, and research in this field may expand greatly in the next decade.

Abstract 1179: Global increase in ultraconserved non-coding RNA expression in pancreatic adenocarcinoma

Transcribed ultraconserved regions (T-UCRs) are a class of 482 non-coding RNAs with 100% sequence conservation among human, rat and mouse genomes. T-UCRs are differentially expressed in colorectal cancer, leukemia and neuroblastoma, however their expression in pancreatic adenocarcinoma (PDAC) has not been studied. We used qPCR to profile all 482 T-UCRs in a variety of pancreatic cancer specimens including pancreatic adenocarcinoma, chronic pancreatitis and benign/normal pancreas and in the pancreas of genetically engineered mice (P48+/Cre;LSL-KRAS G12D and PDX-1-Cre;LSL-KRAS G12D ). Of the 257 expressed T-UCRs in the human pancreas tissues, 166 were differentially expressed in the PDAC compared to normal and adjacent benign pancreas (≥ 1.5 fold; p G12D mice (mean age, 231 days) compared to control. In both the patient and mouse data, the vast majority of the differentially expressed T-UCRs increased with disease progression. Interestingly, the expression pattern among groups of two T-UCRs closely correlated with each other. This was to be expected for T-UCRs directly adjacent to one another in the genome, but surprisingly we found strong correlations among T-UCRs that are located on different chromosomes. This suggests that large groups of T-UCRs are co-expressed in PDAC. In vitro models that simulate the desmoplastic reaction have been shown it to alter gene expression in PDAC. In an effort to understand the mechanism responsible for this global increase in expression in PDAC, the T-UCRs were profiled in normal pancreas (HPDE) cells that were cultured on the extracellular matrix deposited by Panc-1 cells. Ninety-one T-UCRs were increased in the HPDE co-cultures (fold-change > 1.5, p 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 1179. doi:10.1158/1538-7445.AM2011-1179