Biomedical subjects

Carlo M Croce

Publications and source records attributed to Carlo M Croce.

At least 19 recordsLinked to original sources

PubMed2026

A tumor suppressor role of the miR-15b/16-2 cluster in T-cell acute lymphoblastic leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy arising from the neoplastic transformation of immature T cells during their development in the thymus. Deciphering the developmental programs whose dysregulation drives T-ALL pathogenesis is critical for the development of novel targeted therapies, which remain an urgent unmet need for the treatment of this disease. MicroRNAs (miRNAs) have emerged as key posttranscriptional regulators of numerous physiological processes, including cancer. However, the specific role of miRNAs in human T-cell development and T-ALL pathogenesis remains largely unexplored. In this study, we comprehensively evaluated miRNA expression profiles across human T-cell development using microarray analysis and identified a dynamic expression pattern of miR-16-2, which is upregulated during early pre-T-cell proliferative stages up to the resting stage of immature thymocytes immediately preceding T-cell receptor αβ expression and is subsequently downregulated. We also confirmed the coordinated regulation of miR-15b expression, consistent with the reported clustered genomic location of both miRNAs. Notably, functional studies identified the miR-15b/16-2 cluster as a negative regulator of early thymocyte proliferation and demonstrated that overexpression of miR-15b/16-2 in T-ALL cells impaired leukemic growth in vitro and tumor progression in patient-derived xenotransplantation assays. Mechanistically, miR-15b/16-2 represses the expression of the genes encoding BCL-2 and cyclin D3, thereby promoting apoptosis and cell cycle dysregulation in T-ALL cells, characterized by an accumulation of G0-phase cells and a defective transition to the G2/M phase. Overall, these findings support a novel tumor-suppressive function for miR-15b/16-2 in T-ALL and highlight its potential as a promising therapeutic target.

MicroRNAs↗

PubMed2007

Animal models for chronic lymphocytic leukemia.

B-cell chronic lymphocytic leukemia (B-CLL), the most common leukemia in the Western world, results from an expansion of a rare population of CD5+ mature B-lymphocytes. Although clinical features and genomic abnormalities in B-CLL have been studied in considerable detail, the molecular mechanisms underlying disease development has remained unclear until recently. In the last 4 years, several transgenic mouse models for B-CLL were generated. Investigations of these mouse models revealed that deregulation of three pathways, Tcl1-Akt pathway, TNF-NF-kB pathway, and Bcl2-mediated anti-apoptotic pathway, result in the development of B-CLL. While deregulation of TCL1 alone caused a B-CLL phenotype in mice, overexpression of Bcl2 required aberrantly activated TNF-NF-kB pathway signaling to yield the disease phenotype. In this article, we present what has been learned from mice with B-CLL phenotype and how these mouse models of B-CLL were used to test therapeutic treatments for this common leukemia.

Animals↗

PubMed2007

Identification of differentially expressed microRNAs by microarray: a possible role for microRNA genes in pituitary adenomas.

MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression by targeting mRNA. It has been demonstrated that miRNA expression is altered in many human cancers, suggesting that they may play a role in human neoplasia. To determine whether miRNA expression is altered in pituitary adenomas, we analyzed the entire miRNAome in 32 pituitary adenomas and in 6 normal pituitary samples by microarray and by Real-Time PCR. Here, we show that 30 miRNAs are differentially expressed between normal pituitary and pituitary adenomas. Moreover, 24 miRNAs were identified as a predictive signature of pituitary adenoma and 29 miRNAs were able to predict pituitary adenoma histotype. miRNA expression could differentiate micro- from macro-adenomas and treated from non-treated patient samples. Several of the identified miRNAs are involved in cell proliferation and apoptosis, suggesting that their deregulated expression may be involved in pituitary tumorigenesis. Predictive miRNAs could be potentially useful diagnostic markers, improving the classification of pituitary adenomas.

Adenoma↗

PubMed2006

A microRNA signature of hypoxia.

Recent research has identified critical roles for microRNAs in a large number of cellular processes, including tumorigenic transformation. While significant progress has been made towards understanding the mechanisms of gene regulation by microRNAs, much less is known about factors affecting the expression of these noncoding transcripts. Here, we demonstrate for the first time a functional link between hypoxia, a well-documented tumor microenvironment factor, and microRNA expression. Microarray-based expression profiles revealed that a specific spectrum of microRNAs (including miR-23, -24, -26, -27, -103, -107, -181, -210, and -213) is induced in response to low oxygen, at least some via a hypoxia-inducible-factor-dependent mechanism. Select members of this group (miR-26, -107, and -210) decrease proapoptotic signaling in a hypoxic environment, suggesting an impact of these transcripts on tumor formation. Interestingly, the vast majority of hypoxia-induced microRNAs are also overexpressed in a variety of human tumors.

Apoptosis↗

PubMed2006

Knockdown of ALR (MLL2) reveals ALR target genes and leads to alterations in cell adhesion and growth.

ALR (MLL2) is a member of the human MLL family, which belongs to a larger SET1 family of histone methyltransferases. We found that ALR is present within a stable multiprotein complex containing a cohort of proteins shared with other SET1 family complexes and several unique components, such as PTIP and the jumonji family member UTX. Like other complexes formed by SET1 family members, the ALR complex exhibited strong H3K4 methyltransferase activity, conferred by the ALR SET domain. By generating ALR knockdown cell lines and comparing their expression profiles to that of control cells, we identified a set of genes whose expression is activated by ALR. Some of these genes were identified by chromatin immunoprecipitation as direct ALR targets. The ALR complex was found to associate in an ALR-dependent fashion with promoters and transcription initiation sites of target genes and to induce H3K4 trimethylation. The most characteristic features of the ALR knockdown cells were changes in the dynamics and mode of cell spreading/polarization, reduced migration capacity, impaired anchorage-dependent and -independent growth, and decreased tumorigenicity in mice. Taken together, our results suggest that ALR is a transcriptional activator that induces the transcription of target genes by covalent histone modification. ALR appears to be involved in the regulation of adhesion-related cytoskeletal events, which might affect cell growth and survival.

Animals↗

PubMed2006

Physical association with WWOX suppresses c-Jun transcriptional activity.

WWOX is a tumor suppressor that functions as a modular protein partner of transcription factors. WWOX contains two WW domains that mediate protein-protein interactions. In this report, we show that WWOX, via its first WW domain, specifically associates with the proline-rich motif of c-Jun proto-oncogene. Our data show that phosphorylation of c-Jun caused by overexpression of mitogen-activated protein kinase kinase kinase 1 (Mekk1), an upstream activator of c-Jun, enhances the interaction of c-Jun with WWOX. Furthermore, exposure of HaCaT keratinocytes to UVC radiation resulted in the association of endogenous WWOX and c-Jun. The WWOX-c-Jun complexes mainly occur in the cytoplasm. Expression of WWOX attenuates the ability of MEKK1 to increase the activity of a c-Jun-driven activating protein-1 (AP-1)-luciferase reporter plasmid. In contrast, a point mutation in the first WW domain of WWOX has no effect on transactivation of AP-1 when coexpressed with c-Jun protein. Our findings reveal a novel functional cross-talk between c-Jun transcription factor and WWOX tumor suppressor protein.

Cell Line↗

PubMed2006

Tcl1 expression in chronic lymphocytic leukemia is regulated by miR-29 and miR-181.

B-cell chronic lymphocytic leukemia (B-CLL) is the most common human leukemia in the world. Deregulation of the TCL1 oncogene is a causal event in the pathogenesis of the aggressive form of this disease as was verified by using animal models. To study the mechanism of Tcl1 regulation in CLL, we carried out microRNA expression profiling of three types of CLL: indolent CLL, aggressive CLL, and aggressive CLL showing 11q deletion. We identified distinct microRNA signatures corresponding to each group of CLL. We further determined that Tcl1 expression is regulated by miR-29 and miR-181, two microRNAs differentially expressed in CLL. Expression levels of miR-29 and miR-181 generally inversely correlated with Tcl1 expression in the CLL samples we examined. Our results suggest that Tcl1 expression in CLL is, at least in part, regulated by miR-29 and miR-181 and that these microRNAs may be candidates for therapeutic agents in CLLs overexpressing Tcl1.

Chromosome Deletion↗

PubMed2006

Fhit modulates the DNA damage checkpoint response.

In preneoplastic lesions, the DNA damage checkpoint is induced and loss of heterozygosity at the FRA3B/FHIT common chromosome fragile region precedes or is coincident with activation of the checkpoint response in these early stages. Introduction of exogenous Fhit into cells in vitro led to modulation of expression of checkpoint proteins Hus1 and Chk1 at mid-S checkpoint, a modulation that led to induction of apoptosis in esophageal cancer cells but not in noncancerous primary cultures. Mutation of the conserved Fhit tyrosine 114 resulted in failure of this function, confirming the importance of this residue. The results suggest that the DNA damage-susceptible FRA3B/FHIT chromosome fragile region, paradoxically, encodes a protein that is necessary for protecting cells from accumulation of DNA damage through its role in modulation of checkpoint proteins, and inactivation of Fhit contributes to accumulation of abnormal checkpoint phenotypes in cancer development.

Acid Anhydride Hydrolases↗

PubMed2006

Alterations of the tumor suppressor gene ARLTS1 in ovarian cancer.

ARLTS1 is a tumor suppressor gene initially described as a low-penetrance cancer gene: a truncated Trp149Stop (MUT) polymorphism is associated with general familial cancer aggregation and, particularly, high-risk familial breast cancer. DNA hypermethylation has been identified as a mechanism of ARLTS1 expression down-regulation in lung carcinomas and B-cell chronic lymphocytic leukemia. We found that, in the majority of ovarian carcinomas (61.5%) and in a significant proportion of ovarian and breast cancer cell lines (45%), ARLTS1 is strongly down-regulated due to DNA methylation in its promoter region. After ARLTS1 restoration by adenoviral transduction, only the negative TOV-112 and the homozygously mutated (MUT) MCF7 cells, but not the OV-90 cells expressing a normal ARLTS1 product, underwent apoptosis and inhibition of cell growth. Furthermore, ARLTS1 reexpression significantly reduced the tumorigenic potential of TOV-112 in nude mice. On the contrary, the ARLTS1-MUT induced significantly lower levels of apoptosis in infected cells and reduced in vivo tumorigenesis only partially, supporting the hypothesis that Trp149Stop polymorphism is retained in the general population and predisposes to cancer because of a reduction, but not full loss, of normal ARLTS1 function.

ADP-Ribosylation Factors↗

PubMed2006

MicroRNA expression and function in cancer.

MicroRNAs are small non-coding RNAs of 19-24 nucleotides in length that downregulate gene expression during various crucial cell processes such as apoptosis, differentiation and development. Recent work supports a role for miRNAs in the initiation and progression of human malignancies. Large high-throughput studies in patients revealed that miRNA profiling have the potential to classify tumors with high accuracy and predict outcome. Functional studies, some of which involve animal models, indicate that miRNAs act as tumor suppressors and oncogenes. Here, we summarize miRNA-profiling studies in human malignancies and examine the role of miRNAs in the pathogenesis of cancer. We also discuss the implications of these findings for the diagnosis and treatment of cancer.

Animals↗

PubMed2006

MicroRNA expression abnormalities in pancreatic endocrine and acinar tumors are associated with distinctive pathologic features and clinical behavior.

PURPOSE: We investigated the global microRNA expression patterns in normal pancreas, pancreatic endocrine tumors and acinar carcinomas to evaluate their involvement in transformation and malignant progression of these tumor types. MicroRNAs are small noncoding RNAs that regulate gene expression by targeting specific mRNAs for degradation or translation inhibition. Recent evidence indicates that microRNAs can contribute to tumor development and progression and may have diagnostic and prognostic value in several human malignancies. MATERIALS AND METHODS: Using a custom microarray, we studied the global microRNA expression in 12 nontumor pancreas and 44 pancreatic primary tumors, including 12 insulinomas, 28 nonfunctioning endocrine tumors, and four acinar carcinomas. RESULTS: Our data showed that a common pattern of microRNA expression distinguishes any tumor type from normal pancreas, suggesting that this set of microRNAs might be involved in pancreatic tumorigenesis; the expression of miR-103 and miR-107, associated with lack of expression of miR-155, discriminates tumors from normal; a set of 10 microRNAs distinguishes endocrine from acinar tumors and is possibly associated with either normal endocrine differentiation or endocrine tumorigenesis; miR-204 is primarily expressed in insulinomas and correlates with immunohistochemical expression of insulin; and the overexpression of miR-21 is strongly associated with both a high Ki67 proliferation index and presence of liver metastasis. CONCLUSION: These results suggest that alteration in microRNA expression is related to endocrine and acinar neoplastic transformation and progression of malignancy, and might prove useful in distinguishing tumors with different clinical behavior.

Carcinoma, Acinar Cell↗

PubMed2006

The E3 ubiquitin ligase Itch controls the protein stability of p63.

p63, a member of the p53 family of transcription factors, plays an important role in epithelial development, regulating both cell cycle and apoptosis. Even though p63 activity is regulated mainly at the posttranslational level, the control of p63 protein stability is far from being fully understood. Here, we show that the Hect (homologous to the E6-associated protein C terminus)-containing Nedd4-like ubiquitin protein ligase Itch binds, ubiquitylates, and promotes the degradation of p63. The physical interaction occurs at the border between the PY and the SAM (sterile alpha motif) domains; a single Y504F mutation significantly affects p63 degradation. Itch and p63 are coexpressed in the epidermis and in primary keratinocytes where Itch controls the p63 protein steady-state level. Accordingly, p63 protein levels are significantly increased in Itch knockout keratinocytes. These data suggest that Itch has a fundamental role in the mechanism that controls endogenous p63 protein levels and therefore contributes to regulation of p63 in physiological conditions.

Animals↗

PubMed2006

B cell receptors in TCL1 transgenic mice resemble those of aggressive, treatment-resistant human chronic lymphocytic leukemia.

B cell chronic lymphocytic leukemia (B-CLL) is a clonal overgrowth of CD5(+) B lymphocytes. In this disease, the B cell antigen receptor (BCR) is intimately linked to disease severity, because patients with BCRs, comprised of unmutated V(H) genes, follow a much more aggressive course. This and related observations suggest that B-CLL derives from a B cell subset comprised of restricted BCR structural diversity and that antigen-selection and drive are major factors promoting the disease. Nevertheless, the initiating event(s) that lead to the development of B-CLL are still unclear, in part because of the lack of an animal model that spontaneously evolves the molecular abnormalities that occur in the human disease. Because overexpression of the TCL1 gene in murine B cells leads to a CD5(+) B cell lymphoproliferative disorder with many of the features of human B-CLL, we studied leukemias emerging in these mice to examine the extent to which their BCRs resemble those in B-CLL. Our data indicate that the immunoglobulin heavy and light chain rearrangements in TCL1 mice display minimal levels of somatic mutations and exhibit several molecular features found in the human disease. Like human B-CLL, TCL1 leukemic rearrangements from different mice can be very similar structurally and closely resemble autoantibodies and antibodies reactive with microbial antigens. Antigen-binding analyses confirm that selected TCL1 clones react with glycerophospholipid, lipoprotein, and polysaccharides that can be autoantigens and be expressed by microbes. This (auto)antigen-driven mouse model reliably captures the BCR characteristics of aggressive, treatment-resistant human B-CLL.

Amino Acid Sequence↗

PubMed2006

Biological functions of mammalian Nit1, the counterpart of the invertebrate NitFhit Rosetta stone protein, a possible tumor suppressor.

The "Rosetta Stone" hypothesis proposes that the existence of a fusion protein in some organisms predicts that the separate polypeptides function in the same biochemical pathway in other organisms and may physically interact. In Drosophila melanogaster and Caenorhabditis elegans, NitFhit protein is composed of two domains, a fragile histidine triad homolog and a bacterial and plant nitrilase homolog. We assessed the biological effects of mammalian Nit1 expression in comparison with Fhit and observed that: 1) Nit1 expression was observed in most normal tissues and overlapped partially with Fhit expression; 2) Nit1-deficient mouse kidney cells exhibited accelerated proliferation, resistance to DNA damage stress, and increased cyclin D1 expression; 3) cyclin D1 was up-regulated in Nit1 null mammary gland and skin; 4) Nit1 overexpression induced caspase-dependent apoptosis in vitro; and 5) Nit1 allele deficiency led to increased incidence of N-nitrosomethylbenzylamine-induced murine forestomach tumors. Thus, the biological effects of Nit1 expression are similar to Fhit effects. Adenoviruses carrying recombinant NIT1 and FHIT induced apoptosis in Fhit- and Nit1-deficient cells, respectively, suggesting that Nit1-Fhit interaction is not essential for function of either protein. The results suggest that Nit1 and Fhit share tumor suppressor signaling pathways, while localization of the NIT1 gene at a stable, rather than fragile, chromosome site explains the paucity of gene alterations and in frequent loss of expression of the NIT1 gene in human malignancies.

Acid Anhydride Hydrolases↗

PubMed2006

A role for the WWOX gene in prostate cancer.

Expression of the WWOX gene, encompassing the common chromosome fragile site FRA16D, is altered in a large fraction of cancers of various types, including prostate cancer. We have examined expression and biological functions of WWOX in prostate cancer. WWOX mRNA and protein expression were significantly reduced in prostate cancer-derived cells (LNCaP, DU145, and PC-3) compared with noncancer prostate cells (PWR-1E), and WWOX expression was reduced in 84% of prostate cancers, as assessed by immunohistochemical staining. Down-modulation of WWOX expression in the prostate cancer-derived cells is due to DNA hypermethylation in the WWOX regulatory region. Treatment with 5-aza-2'-deoxycytidine (AZA), a DNA methyltransferase inhibitor, and trichostatin A, a histone deacetylase inhibitor, led to increased WWOX mRNA and protein expression in prostate cancer-derived cells, most strikingly in DU145 cells. Transfection-mediated WWOX overexpression in DU145 cells suppressed colony growth (P = 0.0012), and WWOX overexpression by infection with Ad-WWOX virus induced apoptosis through a caspase-dependent mechanism and suppressed cell growth. Lastly, ectopic expression of WWOX by Ad-WWOX infection suppressed tumorigenicity of xenografts in nude mice, and intratumoral AZA treatment halted tumor growth. The data are consistent with a role for WWOX as a prostate cancer tumor suppressor and suggest that WWOX signal pathways should be further investigated in normal and cancerous prostate cells and tissues.

Adenoviridae↗

PubMed2006

Tal1 transgenic expression reveals absence of B lymphocytes.

TAL1 oncogene encodes a helix-loop-helix transcription factor, Tal1, which is required for blood cell development, and its activation is a frequent event in T-cell acute lymphoblastic leukemia. Tal1 interacts and inhibits other helix-loop-helix factors such as E47 and HEB. To investigate the function of Tal1 in B cells, we generated Emu-TAL1 transgenic mouse line, expressing Tal1 in mouse B-cell lineage. Fluorescence-activated cell sorting (FACS) analysis of lymphocytes isolated from spleens of five out of five founders reveals complete absence of IgM- or CD19-expressing cells. Only 2% to 3% of these cells were B220+ and 100% of B220+ cells were CD43+, indicating that these mice were able to make pro-B cells. Similarly, FACS analysis of bone marrow cells in Emu-TAL1 mice revealed complete absence of B220+IgM+ and B220+CD19+ cells. Analysis of the recombination status of IgH genes revealed the presence of D-J but absence or drastic reduction of V-D-J rearrangements. Our results suggest that Tal1 overexpression in B cells results in a phenotype similar to that of B cells of E47/E2A knockout animals. This represents first in vivo evidence that Tal1 can completely inhibit E47/E2A function.

Animals↗

PubMed2006

Preclinical assessment of FHIT gene replacement therapy in human leukemia using a chimeric adenovirus, Ad5/F35.

PURPOSE: Expression of the FHIT protein is lost or reduced in most solid tumors and a significant fraction of hematopoietic malignancies. Adenovirus 5 (Ad5) virus or adeno-associated viral vectors have been used to study the tumor suppressor function of FHIT in solid tumors, but these tools have not been effective in leukemias. We have generated a chimeric FHIT-containing adenovirus composed of Ad5 and the group B adenovirus called F35 with which we have been able to efficiently infect hematopoietic cells. EXPERIMENTAL DESIGN: Infection efficiency of Ad5/F35-FHIT and Ad5/F35-GFP viruses was tested in leukemia cell lines that lacked FHIT expression, and biological effects of successful infection were assessed. An acute myelogenous leukemia, a chronic myelogenous leukemia, and four acute lymphoblastic leukemia human cell lines were examined as well as two EBV-transformed B lymphoblastoid cell lines that expressed endogenous FHIT. RESULTS: Two of four acute lymphoblastic leukemia cell lines, Jurkat and MV4;11, which were efficiently infected with Ad5/F35-FHIT, underwent growth suppression and massive induction of apoptosis without apparent activation of caspase-8 or caspase-2 and late activation of caspase-3. Treatment of infected cells with caspase-9 and caspase-3 inhibitors partially blocked FHIT-induced apoptosis. The two remaining infected acute lymphoblastic leukemia cell lines, Molt-3 and RS4;11, were apparently unaffected. Restoration of FHIT expression in the chronic myelogenous leukemia K562 cell line and the acute myelogenous leukemia KG1a cell line also induced apoptosis but at later time points than seen in the acute lymphoblastic leukemia Jurkat and MV4;11 cell lines. I.v. injection of Ad5/F35-FHIT-infected Jurkat cells resulted in abrogation of tumorigenicity in the NOD/SCID xenogeneic engraftment model. CONCLUSION: FHIT restoration in some FHIT-deficient leukemia cells induces both antiproliferative and proapoptotic effects involving the intrinsic caspase apoptotic pathway.

Acid Anhydride Hydrolases↗

PubMed2006

Influence of FHIT on benzo[a]pyrene-induced tumors and alopecia in mice: chemoprevention by budesonide and N-acetylcysteine.

The FHIT gene has many hallmarks of a tumor-suppressor gene and is involved in a large variety of cancers. We treated A/J mice and (C57BL/6J x 129/SvJ)F1 (B6/129 F1) mice, either wild-type or FHIT+/-, with multiple doses of benzo[a]pyrene (B[a]P) by gavage. B[a]P caused a time-related increase of micronuclei in peripheral blood erythrocytes. Both A/J and B6/129 F1 mice, irrespective of their FHIT status, were sensitive to induction of forestomach tumors, whereas B[a]P induced glandular stomach hyperplasia and a high multiplicity of lung tumors in A/J mice only. Preneoplastic lesions of the uterus were more frequent in FHIT+/- mice. B6/129 F1 mice underwent spontaneous alopecia areata and hair bulb cell apoptosis, which were greatly accelerated either by FHIT heterozygosity or by B[a]P treatment, thus suggesting that FHIT plays a role in the pathogenesis of alopecia areata. The oral administration of either budesonide or N-acetyl-L-cysteine (NAC) inhibited the occurrence of this inflammatory skin disease. In addition, these agents prevented B[a]P-induced glandular stomach hyperplasia and decreased the size of both forestomach tumors and lung tumors in A/J mice. Budesonide also attenuated lung tumor multiplicity. In B6/129 F1 mice, NAC significantly decreased the proliferating cell nuclear antigen in lung tumors. Both budesonide and NAC inhibited B[a]P-induced forestomach tumors and preneoplastic lesions of the respiratory tract in B6/129 F1 mice. In conclusion, heterozygosity for FHIT affects susceptibility of mice to spontaneous alopecia areata and B[a]P-induced preneoplastic lesions of the uterus and does not alter responsiveness to budesonide and NAC.

Acetylcysteine↗