Friday, March 30

microRNA in Cancer

8:00-8:10 Chairperson’s Opening Remarks 

8:30-9:00 Quantitative Measurement of mRNA Targets Following Ectopic Expression of has-miR200c
Graham J. Brock, Ph.D., Staff Scientist & Director of Target and Drug Discovery Facility, Ordway Research Institute
An examination of cell lines using a quantitative RT-PCR based approach revealed variable expression of several microRNAs. Specifically, miR-200c was undetectable in A549 (a lung cancer line) but highly expressed in NHBE (normal human bronchial epithelium). We used a retroviral system to ectopically express miR-200c in A549 cells. Quantitative measurement found a reduction in the levels of several computationally predicted mRNA targets, including the transcriptional repressor TCF8. Significantly, the loss of TCF8 resulted in upregulation of E-cadherin. As downregulation of E-cadherin is reported to be a crucial event in epithelial to mesenchymal transition (EMT) lack of expression of miR-200c (as in A549 cells) could play a significant role in cancer progression. 

9:00-9:30 microRNA Involvement in Cancer Initiation and Progression 
George Calin, M.D., Ph.D., Assistant Professor, Molecular Virology, Immunology and Molecular Genetics, Comprehensive Cancer Center, Ohio State University 
MicroRNA alterations are involved in the initiation and progression of human cancer. The causes of the widespread differential expression of miRNA genes in malignant compared with normal cells can be explained by the location of these genes in cancer-associated genomic regions, by epigenetic mechanisms and by alterations in the microRNA processing machinery. MicroRNA expression profiling of human tumors has identified signatures associated with diagnosis, staging, progression, prognosis and response to treatment. In addition, profiling has been exploited to identify microRNAs genes that may represent downstream targets of activated oncogenic pathways or that are targeting protein coding genes involved in cancer. 

9:30-10:00 Perturbation of microRNA Expression in Cancer 
Jun Lu, Ph.D., Postdoctoral Associate, Cancer Program, Todd Golub Lab, Broad Institute of MIT and Harvard 
MicroRNAs are a class of small RNAs that regulate diverse biological processes. Studies of microRNA expression in human cancers reveal an extensive level of deregulation. However, the functional consequence and the mechanism of such deregulation are not fully clear. Here we present studies that perturb microRNA expression through the knockdown of microRNA processing machinery and by a collection of small molecules. 

10:00-10:45 Coffee Break with Exhibit and Poster Viewing 

10:45-11:15 miRNA Genomic Alterations in Human Epithelial Cancers 
Lin Zhang, M.D., Research Assistant Professor, Center for Research on Reproduction and Women’s Health, Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine 
Cancer is a disease involving multi-step dynamic changes in the genome. However, studies on cancer genome so far have focused most heavily on protein-coding genes, and our knowledge on alterations of the functional non-coding sequences in cancer is largely absent. MicroRNAs (miRNA) are ~22 nt non-coding RNAs, which regulate gene expression in a sequence-specific manner via translational inhibition or mRNA degradation. Mounting evidence is showing that miRNAs may play important roles in tumor development, and a better understanding of their alteration in cancer genome and oncogenic property should contribute to the diagnosis and treatment of cancer. 

11:15-11:45 Roles of microRNAs and Their Targets in Cancer and Development 
Giovanni Stefani, M.D., Ph.D., Frank Slack Lab, Department of Molecular, Cellular and Developmental Biology, Yale University 
microRNAs play important roles in animal development, cell differentiation and metabolism, and have been implicated in human cancer. The let-7 microRNA controls timing of cell cycle exit and terminal differentiation in C. elegans. and is poorly expressed or deleted in human lung cancers. Here we investigated the effects of altered levels of let-7 in cancer cells. We show that inhibiting let-7 function leads to increased cell division in A549 lung cancer cells, in agreement with the proposed role of let-7 as tumor suppressor. Conversely, over-expression of let-7 in cancer cell lines alters cell cycle progression and reduces cell division. An expression profile analysis of cells over-expressing let-7 reveals that multiple genes involved in cell cycle and cell division functions are directly or indirectly repressed by let-7. This work suggests that the let-7 miRNA plays an important role in the regulation of cell proliferation. 

11:45-12:15 microRNA in Brain and Brain Tumors 
Anna M. Krichevsky, Ph.D., Assistant Professor of Neurology/Neuroscience, Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School 
MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate protein expression by targeting the mRNA of protein-coding genes for either cleavage or repression of translation. Some of these molecules regulate important cancer-related genes, both tumor suppressors and oncogenes, and therefore contribute to carcinogenesis. I will discuss our work-in-progress on one of the first discovered onco-miRNAs, miR-21, in human gliomas. Our data suggest that aberrantly expressed miR-21 contributes to the malignant phenotype by blocking expression of critical apoptosis-related genes. 

12:15-1:45 Lunch (on your own)

microRNA as Diagnostic Biomarkers and Targets 
for Therapeutic Development

1:45-2:15 miRNAs: Cancer Biomarkers and Functional Regulators of Cancer Development 
Aimee Jackson, Ph.D., Research Fellow, Biology, Rosetta Inpharmatics, a wholly-owned subsidiary of Merck & Co. Inc. 
microRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by interfering with protein translation or triggering cleavage of the target mRNAs. Recent studies indicate that miRNAs are mechanistically involved in tissue specification, cellular differentiation, and the development of various human cancers. Clarifying the role of miRNAs in tumor development will require a better understanding of target regulation by miRNAs. Each miRNA may regulate hundreds of mRNA targets, but the identities of these targets and the processes they regulate are poorly understood. Here we have explored the use of microarray profiling and functional screening to identify targets and biological processes triggered by transfection of miRNAs into human cells. We characterize a miRNA that coordinately regulates targets that act in concert to control cell cycle progression. 

2:15-2:45 miRNAs as Biomarkers in Blood and Other Biofluids 
Tim Davison, Ph.D., Senior Scientist, Services Division, Asuragen Inc. 
The expression of specific miRNAs can be used to classify cancer patients based upon prognosis, cancer type, and genetic abnormality. The diagnostic potential of miRNAs will ultimately depend upon their characteristics in readily available biofluids like serum and plasma and the analytical sensitivity, specificity, and accuracy of detection methods that can be used in diagnostic laboratories. We have developed a highly sensitive and quantitative method for miRNA expression analysis and used it to evaluate miRNAs in a variety of biofluids. Interestingly, miRNAs are abundant in serum, plasma, saliva, and urine and exhibit surprising stability and donor-to-donor consistency. These data as well as studies showing potential diagnostic applications for miRNAs in leukemia and pancreatic cancer patients will be presented. 

2:45-3:30 Refreshment Break with Exhibit and Poster Viewing 

3:30-4:00 microRNAs in Human Cancers 
Ayelet Chayut, Ph.D., Vice President, Discovery; and Dalia Cohen, Ph.D., Executive Vice President, Head, Research & Development, Rosetta Genomics Ltd. 
microRNAs are short non-coding RNAs that regulate gene expression through post-transcriptional suppression of mRNA. Rosetta Genomics integrative bioinformatics/ biological approach has led to the discovery and validation of several hundreds human microRNAs, and was followed by the development of robust and sensitive methods for extraction and profiling of microRNAs. This extensive platform is applied to study microRNAs expression and signatures in human cancers for the development of novel diagnostic and therapeutic approaches. 

4:00-4:30 Antagomirs as Potential Therapeutic Agents 
Muthiah Manoharan, Ph.D., Vice President, Drug Discovery, Alnylam Pharmaceuticals, Inc. 
The first in vivo demonstration of turning-off microRNAs was achieved by a cholesterol conjugated analogs of anti-miRNA RNAs. This class of chemically engineered oligonucleotides, termed antagomirs, based on their precise antagonist function of miRNAs, has been used for efficient and specific silencing of endogenous miRNAs in mice. The silencing of endogenous miRNAs using this strategy is specific, efficient, observed within 24 hrs after administration and long lasting for more than 3 weeks. Progress in this area to identify potential therapeutic agents will be presented. 

4:30-5:00 microRNAs as Targets for Antisense-Based Therapeutics 
Sakari Kauppinen, Ph.D., microRNA Research Unit, Department of Medical Biochemistry and Genetics, University of Copenhagen; and Santaris Pharma 
Silencing of disease-associated microRNAs using antisense targeting may yield patient benefits unobtainable by other therapeutic approaches. LNA is the first true conformational analogue of RNA, in which the furanose ring in the sugar-phosphate backbone is locked in an RNA-like, C3’-endo conformation. This conformational restriction results in unprecedented binding affinity between single-stranded LNA oligonucleotides and their complementary RNA targets. We report here that using rational design, LNA-antimiR oligonucleotides can be used as effective therapeutic molecules for sequence-specific inhibition of disease related miRNAs in vitro and in vivo. 

5:00 Close of Conference