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Biomedical subjects

Juan C Cigudosa

Publications and source records attributed to Juan C Cigudosa.

At least 19 recordsLinked to original sources
PubMed2007

Extreme sensitivity to Yondelis (Trabectedin, ET-743) in low passaged sarcoma cell lines correlates with mutated p53.

Yondelis (Trabectedin, ET-743) is a marine anticancer agent currently in Phase II/III development in patients with advanced pretreated soft tissue sarcoma. In the present study, we generated a panel of low passaged tumor cell lines from samples explanted from chemonaive sarcoma patients with different tumor types. We assessed in vitro sensitivity/resistance to Trabectedin and doxorubicin in a panel of sarcoma cell lines and examined the correlation between molecular alterations in DNA repair genes and sensitivity to Trabectedin. We treated cell lines with Trabectedin and doxorubicin in both 96-h and clonogenic assays. In both assays, well-defined groups of resistant and sensitive cell lines were observed. Resistance to Trabectedin did not correlate with resistance to doxorubicin, indicating that the two drugs may have different mechanisms of resistance. p53 mutations and deletions correlated with extreme sensitivity (IC50 < 1 nM) to Trabectedin (P < 0.01). In a pair of isogenic cell lines differing only in the presence or absence of wild-type p53, the absence of p53 rendered cells threefold more sensitive to Trabectedin.

Cell Proliferation↗
PubMed2006

Release of hypoacetylated and trimethylated histone H4 is an epigenetic marker of early apoptosis.

Nuclear events such as chromatin condensation, DNA cleavage at internucleosomal sites, and histone release from chromatin are recognized as hallmarks of apoptosis. However, there is no complete understanding of the molecular events underlying these changes. It is likely that epigenetic changes such as DNA methylation and histone modifications that are involved in chromatin dynamics and structure are also involved in the nuclear events described. In this report we have shown that apoptosis is associated with global DNA hypomethylation and histone deacetylation events in leukemia cells. Most importantly, we have observed a particular epigenetic signature for early apoptosis defined by a release of hypoacetylated and trimethylated histone H4 and internucleosomal fragmented DNA that is hypermethylated and originates from perinuclear heterochromatin. These findings provide one of the first links between apoptotic nuclear events and epigenetic markers.

Apoptosis↗
PubMed2006

Identification of recurrent chromosomal breakpoints in multiple myeloma with complex karyotypes by combined G-banding, spectral karyotyping, and fluorescence in situ hybridization analyses.

The description of novel chromosomal aberrations in multiple myeloma (MM) remains necessary to fully understand the pathogenesis of this heterogeneous disease. Therefore, we have used spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH) with locus-specific probes to characterize the chromosomal abnormalities in 11 MM cases in which G-banding revealed a complex karyotype. SKY refined G-banding karyotypes in all cases. Recurrent breakpoints involved bands Xp11, 8q24, 11q13, 12q13, 13q21, and 14q32. In addition, combined SKY and FISH analyses permitted us to identify a subset of patients harboring 22q11.2 rearrangements not involving the IGL locus. This finding suggests the presence of other gene(s) in band 22q11 that might be implicated in MM pathogenesis. Moreover, band 1p13 was identified as a novel partner of immunoglobulin (IG) translocations in MM. Finally, using interphase FISH, we have detected interstitial deletions in 13q14 and 17p13, as well as cryptic translocations affecting IGH, which were neither detected by G-banding nor by SKY. The results of the present study suggest the existence of hitherto unknown nonrandom chromosomal changes that may play a role in the pathogenesis of MM. Our findings underline the importance of the combination of banding, SKY, and FISH analyses to increase the accuracy of karyotype interpretation in plasma cell neoplasias.

Chromosome Aberrations↗
PubMed2006

Variability in the expression of polycomb proteins in different normal and tumoral tissues. A pilot study using tissue microarrays.

In spite of the known function of polycomb group (PcG) genes in stem cell self-renewal, control of cellular proliferation and differentiation, its role in cancer pathogenesis is still poorly understood. We studied the expression by immunohistochemistry of several PcG-maintenance complex proteins (RING1, RNF2, BMI1, MEL18, HPH1 and RYBP) in nontumoral (154 samples) and tumoral (550 samples) human tissues using Tissue Microarrays. For selected genes (BMI1 and RING1) FISH analysis has been also carried out. PcG proteins had a tissue- and cell-type-specific expression pattern. Some of them were highly selectively expressed, such as HPH1, which was detected in germ cells in testis, pituitary and parathyroid glands and Langerhans islets, and RYBP, which was found in placenta, umbilical cord and thyroid gland. By contrast, RING1 was ubiquitously expressed in every normal tissue analyzed. Changes in expression associated with tumoral transformation have been found for BMI1 and RNF2, which exhibited increased expression in a large series of tumors, including gastrointestinal tumors, pituitary and parathyroid adenomas, and lymphomas, compared with their expression in normal-cell counterparts. The high level of expression of BMI1 protein observed in mantle-cell lymphomas and pituitary adenomas is associated in some cases with amplification of BMI1 locus. These findings imply that upregulation of BMI1 may constitute a malignancy marker in different types of cancer, mainly in lymphoid and endocrine tumors. RING1 was lost in a group of renal-cell carcinomas and testicular germ-cell tumors. Lastly, RYBP is anomalously expressed in Hodgkin's lymphomas and oligodendrogliomas, among others tumors. A significant finding of the study is the identification of unique PcG profiles for some tumors, such as testicular germ-cell tumors, which have high levels of HPH1 expression and loss of RING1 and/or BMI1; pituitary adenomas, which expressed every PcG protein analyzed; and clear-cell renal-cell carcinoma, which was the only tumor other than testicular germ-cell tumors that did not express RING1.

Carrier Proteins↗
PubMed2006

Genomic and expression profiling identifies the B-cell associated tyrosine kinase Syk as a possible therapeutic target in mantle cell lymphoma.

Among B-cell lymphomas mantle cell lymphoma (MCL) has the worst prognosis. By using a combination of genomic and expression profiling (Affymetrix GeneChip Mapping 10k Xba131 and U133 set), we analysed 26 MCL samples to identify genes relevant to MCL pathogenesis and that could represent new therapeutic targets. Recurrent genomic deletions and gains were detected. Genes were identified as overexpressed in regions of DNA gain on 3q, 6p, 8q, 9q, 16p and 18q, including the cancer genes BCL2 and MYC. Among the transcripts with high correlation between DNA and RNA, we identified SYK, a tyrosine kinase involved in B-cell receptor signalling. SYK was amplified at DNA level, as validated by fluorescence in situ hybridisation (FISH) analysis, and overexpressed at both RNA and protein levels in the JeKo-1 cell line. Low-level amplification, with protein overexpression of Syk was demonstrated by FISH in a small subset of clinical samples. After treatment with low doses of the Syk inhibitor piceatannol, cell proliferation arrest and apoptosis were induced in the cell line overexpressing Syk, while cells expressing low levels of Syk were much less sensitive. A combination of genomic and expression profiling suggested Syk inhibition as a new therapeutic strategy to be explored in lymphomas.

Apoptosis↗
PubMed2006

Identification of overexpressed genes in frequently gained/amplified chromosome regions in multiple myeloma.

BACKGROUND AND OBJECTIVES: Multiple myeloma (MM) is a malignancy characterized by clonal expansion of plasma cells. In 50% of the cases, the neoplastic transformation begins with a chromosomal translocation that juxtaposes the IGH gene locus to an oncogene. Gene copy number changes are also frequent in MM but less characterized than in other neoplasias. We aimed to characterize genes that are amplified and overexpressed in human myeloma cell lines (HMCL) to provide putative molecular targets for MM therapy. DESIGN AND METHODS: Nine HMCL were characterized by fluorescent in situ hybridization, comparative genomic hybridization (CGH) and cDNA microarrays for gene expression profiling and copy number changes. RESULTS: After defining the IGH-translocations present in the cell lines, we conducted expression-profiling analysis. Supervised analysis identified 166 genes with significantly different expression among the cell lines harboring MMSET/FGFR3 (4p16), MAF (16q) and CCND1 (11q13) rearrangements. Array-CGH was then performed. Five chromosomes recurrently affected by gains/amplifications in primary samples and cell lines were analyzed in detail. Sixty amplified and overexpressed genes were found and 25 (42%) of them were only overexpressed when amplified; moreover, six showed a significant association between overexpression and gain/amplification. We also found co-amplification and overexpression for genes located within the same amplicons, such as MALT1 and BCL2. INTERPRETATION AND CONCLUSIONS: Parallel analysis of gene copy numbers and expression levels by cDNA microarray in MM allowed efficient identification of genes whose expression levels are elevated because of increased copy number. This is the first time that MALT1 and BCL2 have been shown to be overexpressed and amplified in MM.

Caspases↗
PubMed2005

Chromosomal instability and phenotypic plasticity during the squamous-spindle carcinoma transition: association of a specific T(14;15) with malignant progression.

In mouse epidermal carcinogenesis, the latest stage of malignant progression involves the transition from squamous cell carcinoma to a highly aggressive type of tumor with spindle morphology. In this work, we have isolated a minor epithelial cell subpopulation (CarC-R) contained in the highly malignant spindle carcinoma cell line CarC. CarC-R exhibited a drastic reduction in tumorigenicity when compared with CarC, but CarC-R-induced tumors were mainly sarcomatoid, although they subsequently reverted to the epithelial phenotype when tumor explants were recultured in vitro. Several single-cell clones with either stable epithelial or fibroblastic phenotypes were isolated from an explanted CarC-R tumor (CarC-RT). All these cell lines contained the same specific point mutation in H-Ras codon 61, but while CarC spindle cells had lost the normal H-Ras allele, it was retained in CarC-R- and CarC-RT-derived cell lines. Furthermore, CarC cells have inactivated p16INK4a and p19INK4a/ARF transcription, while CarC-R and CarC-RT clones expressed p19 mRNA and protein but not p16. Altogether, these results suggest that CarC-R represents a precursor stage to CarC in malignant progression. Spectral karyotyping analysis revealed that CarC-R was highly aneuploid and contained many chromosomal abnormalities. In contrast, CarC had a diploid or tetraploid modal chromosome number and contained a specific T(14;15) translocation in all of the analysed metaphases. The T(14;15) translocation was present in only a minority (1.9%) of CarC-R cells, but it was widely spread in CarC-RT and its derived cell clones, regardless of their epithelial or fibroblastic phenotype, indicating that T(14;15) segregates with malignancy.

Animals↗
PubMed2005

Epithelioid sarcoma with SYT-SSX1 fusion gene expression: molecular and cytogenetic analysis.

Epithelioid sarcoma is a rare malignant soft tissue tumor of unknown histogenesis, characterized by the epithelioid morphology of tumor cells and co-expression of epithelial and mesenchymal lineage proteins. A common epithelial and mesenchymal immunophenotype is also found in another soft tissue tumor, the biphasic subtype of synovial sarcoma. Furthermore, the presence of a breakpoint at 18q11 in epithelioid sarcoma, similar to that found in synovial sarcoma, has been reported. These facts would support the hypothesis that both tumors may share a common histogenetic background. However, expression of the SYT-SSX fusion genes has been investigated in epithelioid sarcoma with negative results. We report, to our knowledge, the first epithelioid sarcoma in which the presence of SYT-SSX1 fusion gene has been detected by means of conventional RT-PCR analysis and sequencing, real-time RT-PCR and FISH. The SYT-SSX1 gene fusion was identified in a small proportion of tumoral cells. This finding supports a likely common histogenetic background for both epithelioid sarcoma and synovial sarcoma.

Adolescent↗
PubMed2005

Epigenetic differences arise during the lifetime of monozygotic twins.

Monozygous twins share a common genotype. However, most monozygotic twin pairs are not identical; several types of phenotypic discordance may be observed, such as differences in susceptibilities to disease and a wide range of anthropomorphic features. There are several possible explanations for these observations, but one is the existence of epigenetic differences. To address this issue, we examined the global and locus-specific differences in DNA methylation and histone acetylation of a large cohort of monozygotic twins. We found that, although twins are epigenetically indistinguishable during the early years of life, older monozygous twins exhibited remarkable differences in their overall content and genomic distribution of 5-methylcytosine DNA and histone acetylation, affecting their gene-expression portrait. These findings indicate how an appreciation of epigenetics is missing from our understanding of how different phenotypes can be originated from the same genotype.

5-Methylcytosine↗
PubMed2005

Spontaneous human adult stem cell transformation.

Human adult stem cells are being evaluated widely for various therapeutic approaches. Several recent clinical trials have reported their safety, showing them to be highly resistant to transformation. The clear similarities between stem cell and cancer stem cell genetic programs are nonetheless the basis of a recent proposal that some cancer stem cells could derive from human adult stem cells. Here we show that although they can be managed safely during the standard ex vivo expansion period (6-8 weeks), human mesenchymal stem cells can undergo spontaneous transformation following long-term in vitro culture (4-5 months). This is the first report of spontaneous transformation of human adult stem cells, supporting the hypothesis of cancer stem cell origin. Our findings indicate the importance of biosafety studies of mesenchymal stem cell biology to efficiently exploit their full clinical therapeutic potential.

Adipose Tissue↗
PubMed2005

HCAD, closing the gap between breakpoints and genes.

Recurrent chromosome aberrations are an important resource when associating human pathologies to specific genes. However, for technical reasons a large number of chromosome breakpoints are defined only at the level of cytobands and many of the genes involved remain unidentified. We developed a web-based information system that mines the scientific literature and generates textual and comprehensive information on all human breakpoints. We show that the statistical analysis of this textual information and its combination with genomic data can identify genes directly involved in DNA rearrangements. The Human Chromosome Aberration Database (HCAD) is publicly accessible at http://www.pdg.cnb.uam.es/UniPub/HCAD/.

Chromosome Breakage↗
PubMed2005

A novel candidate region linked to development of both pheochromocytoma and head/neck paraganglioma.

Although the histologic distinction between pheochromocytomas and head and neck paragangliomas is clear, little is known about the genetic differences between them. To date, various sets of genes have been found to be involved in inherited susceptibility to developing both tumor types, but the genes involved in sporadic pathogenesis are still unknown. To define new candidate regions, we performed CGH analysis on 29 pheochromocytomas and on 24 paragangliomas mainly of head and neck origin (20 of 24), which allowed us to differentiate between the two tumor types. Loss of 3q was significantly more frequent in pheochromocytomas, and loss of 1q appeared only in paragangliomas. We also found gain of 11q13 to be a significantly frequent alteration in malignant cases of both types. In addition, recurrent loss of 8p22-23 was found in 62% of pheochromocytomas (including all malignant cases) versus in 33% of paragangliomas, suggesting that this region contains candidate genes involved in the pathogenesis of this abnormality. Using FISH analysis on tissue microarrays, we confirmed genomic deletion of this region in 55% of pheochromocytomas compared to 12% of paragangliomas. Loss of 8p22-23 appears to be an important event in the sporadic development of these tumors, and additional molecular studies are necessary to identify candidate genes in this chromosomal region.

Adolescent↗
PubMed2005

Gains, losses and complex karyotypes in myeloid disorders: a light at the end of the tunnel.

Complex karyotypes are seen in approximately 15% of de novo MDS/AML and in up to 50% of therapy-related MDS/AML. These patients represent a therapeutic challenge for which no current treatment approach is satisfactory. Therefore, a large number of genetic studies using cytogenetic molecular techniques have been performed to better define the chromosomal abnormalities in this poor-prognosis group. On the basis of the available data from several studies of AML with complex karyotypes, similar findings on recurrent breakpoints and frequently lost and gained chromosomal regions have been observed. The most frequent rearrangements, in all the published series, were unbalanced translocations leading to loss of chromosomal material. Overall, loss of 5q and/or 7q chromosomal material seemed the more common event, and losses of 5q, 7q, and 17p in combination were observed in many cases. Overrepresented chromosomal material from 8q, 11q23, 21q and 22q was found recurrently and in several cases this was due to the amplification of the MLL (located at 11q23) and AML1/RUNX1 (located at 22q22) genes. As a result of these findings, the presence of MLL copy gain/amplifications or losses of the short arm of chromosome 17, in association with 5/5q, have been found to be indicators of an extremely poor prognosis. Interestingly, this non-random pattern of DNA gains and losses, that characterizes AML cases with complex karyotypes, affects the gene expression pattern, and a specific expression profile, characterized by the upregulation of genes involved in the DNA repair and chromosome segregation pathways, has been recently reported. Therefore, a comprehensive genome-wide analysis of patients with AML or MDS with complex karyotypes has led to a better characterization of chromosomal aberrations. These specific alterations could be used in the near future as therapeutic targets or markers for the risk stratification of patients, detection of minimal residual disease and the development of new therapeutic interventions.

Chromosome Segregation↗
PubMed2005

Phenotypic characterization of BRCA1 and BRCA2 tumors based in a tissue microarray study with 37 immunohistochemical markers.

Familial breast cancers that are associated with BRCA1 or BRCA2 germline mutations differ in both their morphological and immunohistochemical characteristics. To further characterize the molecular difference between genotypes, the authors evaluated the expression of 37 immunohistochemical markers in a tissue microarray (TMA) containing cores from 20 BRCA1, 14 BRCA2, and 59 sporadic age-matched breast carcinomas. Markers analyzed included, amog others, common markers in breast cancer, such as hormone receptors, p53 and HER2, along with 15 molecules involved in cell cycle regulation, such as cyclins, cyclin dependent kinases (CDK) and CDK inhibitors (CDKI), apoptosis markers, such as BCL2 and active caspase 3, and two basal/myoepithelial markers (CK 5/6 and P-cadherin). In addition, we analyzed the amplification of CCND1, CCNE, HER2 and MYC by FISH. Unsupervised cluster data analysis of both hereditary and sporadic cases using the complete set of immunohistochemical markers demonstrated that most BRCA1-associated carcinomas grouped in a branch of ER-, HER2-negative tumors that expressed basal cell markers and/or p53 and had higher expression of activated caspase 3. The cell cycle proteins associated with these tumors were E2F6, cyclins A, B1 and E, SKP2 and Topo IIalpha. In contrast, most BRCA2-associated carcinomas grouped in a branch composed by ER/PR/BCL2-positive tumors with a higher expression of the cell cycle proteins cyclin D1, cyclin D3, p27, p16, p21, CDK4, CDK2 and CDK1. In conclusion, our study in hereditary breast cancer tumors analyzing 37 immunohistochemical markers, define the molecular differences between BRCA1 and BRCA2 tumors with respect to hormonal receptors, cell cycle, apoptosis and basal cell markers.

Adult↗
PubMed2004

Epigenetic loss of the familial tumor-suppressor gene exostosin-1 (EXT1) disrupts heparan sulfate synthesis in cancer cells.

Germline mutations in the Exostoses-1 gene (EXT1) are found in hereditary multiple exostoses syndrome, which is characterized by the formation of osteochondromas and an increased risk of chondrosarcomas and osteosarcomas. However, despite its putative tumor-suppressor function, little is known of the contribution of EXT1 to human sporadic malignancies. Here, we report that EXT1 function is abrogated in human cancer cells by transcriptional silencing associated with CpG island promoter hypermethylation. We also show that, at the biochemical and cellular levels, the epigenetic inactivation of EXT1, a glycosyltransferase, leads to the loss of heparan sulfate (HS) synthesis. Reduced HS production can be reversed by the use of a DNA demethylating agent. Furthermore, the re-introduction of EXT1 into cancer cell lines displaying methylation-dependent silencing of EXT1 induces tumor-suppressor-like features, e.g. reduced colony formation density and tumor growth in nude mouse xenograft models. Screening a large collection of human cancer cell lines (n=79) and primary tumors (n=454) from different cell types, we found that EXT1 CpG island hypermethylation was common in leukemia, especially acute promyelocytic leukemia and acute lymphoblastic leukemia, and non-melanoma skin cancer. These findings highlight the importance of EXT1 epigenetic inactivation, leading to an abrogation of HS biosynthesis, in the processes of tumor onset and progression.

Animals↗