Carlo M. Croce

Bio: Carlo M. Croce is an academic researcher from Ohio State University. The author has contributed to research in topics: microRNA & Cancer. The author has an hindex of 198, co-authored 1135 publications receiving 189007 citations. Previous affiliations of Carlo M. Croce include University of Nebraska Medical Center & University of California, Los Angeles.

MicroRNA expression profiles for the NCI-60 cancer cell panel

Abstract: Advances in the understanding of cancer cell biology and response to drug treatment have benefited from new molecular technologies and methods for integrating information from multiple sources. The NCI-60, a panel of 60 diverse human cancer cell lines, has been used by the National Cancer Institute to screen >100,000 chemical compounds and natural product extracts for anticancer activity. The NCI-60 has also been profiled for mRNA and protein expression, mutational status, chromosomal aberrations, and DNA copy number, generating an unparalleled public resource for integrated chemogenomic studies. Recently, microRNAs have been shown to target particular sets of mRNAs, thereby preventing translation or accelerating mRNA turnover. To complement the existing NCI-60 data sets, we have measured expression levels of microRNAs in the NCI-60 and incorporated the resulting data into the CellMiner program package for integrative analysis. Cell line groupings based on microRNA expression were generally consistent with tissue type and with cell line clustering based on mRNA expression. However, mRNA expression seemed to be somewhat more informative for discriminating among tissue types than was microRNA expression. In addition, we found that there does not seem to be a significant correlation between microRNA expression patterns and those of known target transcripts. Comparison of microRNA expression patterns and compound potency patterns showed significant correlations, suggesting that microRNAs may play a role in chemoresistance. Combined with gene expression and other biological data using multivariate analysis, microRNA expression profiles may provide a critical link for understanding mechanisms involved in chemosensitivity and chemoresistance.

ATM mutations in B-cell chronic lymphocytic leukemia

Abstract: Mutations in the ATM gene located on the long arm of chromosome 11 at 11q22-23 cause ataxia-telangiectasia, an autosomal recessive disorder that is associated with increased incidence of malignancy and, particularly, lymphoid tumors. A role for ATM in the development of sporadic T-cell chronic leukemias is supported by the finding of loss of heterozygosity at 11q22-23 and ATM mutations in leukemias carrying TCL-1 rearrangements. Approximately 14% of B-cell chronic lymphocytic leukemia (B-CLL), the most common adult leukemia, carry deletions of the long arm of chromosome 11 at 11q22-23. Loss of heterozygosity at 11q22-23 and, more recently, absence of ATM protein, have been associated with poor prognosis in B-CLL. To determine whether the ATM gene is altered in B-CLL, we have sequenced individual ATM exons in six B-CLL cases. We show that the ATM gene is mutated in a fraction of B-CLLs and that mutations can be present in the germ line of patients, suggesting that ATM heterozygotes may be predisposed to B-CLL.

MicroRNAs in normal and malignant hematopoiesis.

Abstract: Purpose of reviewThe discovery of a novel class of gene regulators, named microRNAs, has changed the landscape of human genetics. In hematopoiesis, recent work has improved our understanding of the role of microRNAs in hematopoietic differentiation and leukemogenesis.Recent findingsUsing animal mode

MiR-145 participates with TP53 in a death-promoting regulatory loop and targets estrogen receptor-α in human breast cancer cells

Abstract: Understanding the consequences of miR-145 reintroduction in human breast cancer (BC) could reveal its tumor-suppressive functions and may disclose new aspects of BC biology. Therefore, we characterized the effects of miR-145 re-expression in BC cell lines by using proliferation and apoptosis assays. As a result, we found that miR-145 exhibited a pro-apoptotic effect, which is dependent on TP53 activation, and that TP53 activation can, in turn, stimulate miR-145 expression, thus establishing a death-promoting loop between miR-145 and TP53. We also found that miR-145 can downregulate estrogen receptor-α (ER-α) protein expression through direct interaction with two complementary sites within its coding sequence. In conclusion, we described a tumor suppression function of miR-145 in BC cell lines, and we linked miR-145 to TP53 and ER-α. Moreover, our findings support a view that miR-145 re-expression therapy could be mainly envisioned in the specific group of patients with ER-α-positive and/or TP53 wild-type tumors.

miR-181b negatively regulates activation-induced cytidine deaminase in B cells

Abstract: Activated B cells reshape their primary antibody repertoire after antigen encounter by two molecular mechanisms: somatic hypermutation (SHM) and class switch recombination (CSR). SHM and CSR are initiated by activation-induced cytidine deaminase (AID) through the deamination of cytosine residues on the immunoglobulin loci, which leads to the generation of DNA mutations or double-strand break intermediates. As a bystander effect, endogenous AID levels can also promote the generation of chromosome translocations, suggesting that the fine tuning of AID expression may be critical to restrict B cell lymphomagenesis. To determine whether microRNAs (miRNAs) play a role in the regulation of AID expression, we performed a functional screening of an miRNA library and identified miRNAs that regulate CSR. One such miRNA, miR-181b, impairs CSR when expressed in activated B cells, and results in the down-regulation of AID mRNA and protein levels. We found that the AID 3′ untranslated region contains multiple putative binding sequences for miR-181b and that these sequences can be directly targeted by miR-181b. Overall, our results provide evidence for a new regulatory mechanism that restricts AID activity and can therefore be relevant to prevent B cell malignant transformation.

Gapped BLAST and PSI-BLAST: a new generation of protein database search programs.

Abstract: The BLAST programs are widely used tools for searching protein and DNA databases for sequence similarities. For protein comparisons, a variety of definitional, algorithmic and statistical refinements described here permits the execution time of the BLAST programs to be decreased substantially while enhancing their sensitivity to weak similarities. A new criterion for triggering the extension of word hits, combined with a new heuristic for generating gapped alignments, yields a gapped BLAST program that runs at approximately three times the speed of the original. In addition, a method is introduced for automatically combining statistically significant alignments produced by BLAST into a position-specific score matrix, and searching the database using this matrix. The resulting Position-Specific Iterated BLAST (PSIBLAST) program runs at approximately the same speed per iteration as gapped BLAST, but in many cases is much more sensitive to weak but biologically relevant sequence similarities. PSI-BLAST is used to uncover several new and interesting members of the BRCT superfamily.

Analyzing real-time PCR data by the comparative C(T) method.

Abstract: Two different methods of presenting quantitative gene expression exist: absolute and relative quantification. Absolute quantification calculates the copy number of the gene usually by relating the PCR signal to a standard curve. Relative gene expression presents the data of the gene of interest relative to some calibrator or internal control gene. A widely used method to present relative gene expression is the comparative C(T) method also referred to as the 2 (-DeltaDeltaC(T)) method. This protocol provides an overview of the comparative C(T) method for quantitative gene expression studies. Also presented here are various examples to present quantitative gene expression data using this method.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。