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Fabio Salamanca

Publications and source records attributed to Fabio Salamanca.

11 recordsLinked to original sources
PubMed2007

Expression and function of utrophin associated protein complex in stretched endothelial cells: dissociation and activation of eNOS.

Several studies have emphasized the relevance of dystrophin-associated protein complex (DAPC) to maintain the vascular function. Previously we postulated the presence of an utrophin associated protein complex (UAPC) in endothelium from umbilical cord vessels. In the present work, we demonstrate that utrophin (UTR) indeed forms a complex, with beta-dystroglycan (DG), epsilon-sarcoglycan (SG), caveolin-1 (cav-1), and endothelial nitric oxide synthase (eNOS) in human umbilical vein endothelial cells (HUVEC) by co-immunoprecipitation analysis. Additionally, we observed an increment in the protein levels of epsilon-SG, beta-DG, UTR and cav-1 after mechanical stretching. Interestingly, this stimulus also induced eNOS up-regulation, activation and release from the UAPC, and led to a significant increase in nitric oxide (NO) production. Finally, we propose that UAPC in HUVECs may play an important role in the regulation of vascular tone.

Caveolin 1↗
PubMed2006

Partial characterization of the mouse alpha-sarcoglycan promoter and its responsiveness to MyoD.

The mouse alpha-sarcoglycan gene is expressed in muscle cells during differentiation, but its transcriptional regulation is not understood. We have characterized the promoter region of the mouse alpha-sarcoglycan gene. This region is composed of positive and negative regulatory elements that respond to the myogenic differentiation environment. Accordingly, MyoD transactivates the alpha-sarcoglycan full-length and the proximal promoter. Chromatin immunoprecipitation assays revealed that MyoD, TFIID, and TFIIB interact with the distal promoter in C2C12 myoblasts, a stage at which the alpha-SG promoter appears to drive basal activity. In myotubes, such factors are located concomitantly at the distal promoter and at a DNA region around the proximal promoter. In agreement with these results, TFIID and TFIIB co-immunoprecipitate with MyoD. We conclude that the alpha-SG promoter is activated by MyoD, which interacts with TFIID and TFIIB in a protein complex differentially located at the distal promoter and around the proximal promoter during myogenic cell differentiation.

Animals↗
PubMed2005

A molecular analysis by gene expression profiling reveals Bik/NBK overexpression in sporadic breast tumor samples of Mexican females.

BACKGROUND: Breast cancer is one of the most frequent causes of death in Mexican women over 35 years of age. At molecular level, changes in many genetic networks have been reported as associated with this neoplasia. To analyze these changes, we determined gene expression profiles of tumors from Mexican women with breast cancer at different stages and compared these with those of normal breast tissue samples. METHODS: 32P-radiolabeled cDNA was synthesized by reverse transcription of mRNA from fresh sporadic breast tumor biopsies, as well as normal breast tissue. cDNA probes were hybridized to microarrays and expression levels registered using a phosphorimager. Expression levels of some genes were validated by real time RT-PCR and immunohistochemical assays. RESULTS: We identified two subgroups of tumors according to their expression profiles, probably related with cancer progression. Ten genes, unexpressed in normal tissue, were turned on in some tumors. We found consistent high expression of Bik gene in 14/15 tumors with predominant cytoplasmic distribution. CONCLUSION: Recently, the product of the Bik gene has been associated with tumoral reversion in different neoplasic cell lines, and was proposed as therapy to induce apoptosis in cancers, including breast tumors. Even though a relationship among genes, for example those from a particular pathway, can be observed through microarrays, this relationship might not be sufficient to assign a definitive role to Bik in development and progression of the neoplasia. The findings herein reported deserve further investigation.

Adult↗
PubMed2004

Identification of chromosomal changes with comparative genomic hybridization in sporadic breast cancer in Mexican women.

Breast cancer is the second leading cause of death in women older than 35 years in Mexico. In this study, we used comparative genomic hybridization (CGH) to analyze sporadic breast cancers at stages II and III from untreated patients. We obtained 4.1 chromosomal alterations per sample, less than in previous reports. We identified a small region in Xq27 with high-level amplification in 3 of 16 samples. This amplification has been reported only in pancreatic and gastric cancer cell lines and in testis tumors; in addition, this amplification had been reported in one primary breast cancer, but in a more extended region that we identified. We also identified a loss in 2p13, not previously reported in this neoplasia. The most frequent alterations were amplifications in 4q, 5q, 8q, 12p, and 13q and losses in 1p, 8p, 16p, 19q, and Xp. CGH provides data for better understanding of molecular events in this neoplasia.

Adult↗
PubMed2004

NFI-C2 negatively regulates alpha-sarcoglycan promoter activity in C2C12 myoblasts.

alpha-Sarcoglycan striated muscle-specific protein is a member of the sarcoglycan-sarcospan complex. Positive and negative transcriptional regulation of sarcoglycan genes are important in sarcoglycan's intracellular localization and sarcolemmal stability. In the present work we assessed the function of NFI transcription factors in the regulation of alpha-sarcoglycan promoter through the C2C12 cell line differentiation. NFI factors act alternatively as activators and negative modulators of alpha-sarcoglycan promoter activity. In myoblasts NFI-A1.1 and NFI-B2 are activators, whereas NFI-C2 and NFI-X2 are negative regulators. In myotubes, all NFI members are activators, being NFI-C2 the less potent. We identified the alpha-sarcoglycan promoter NFI-C2 response element by testing progressive deletion constructs and point mutations in C2C12 cells over-expressing NFI-C2. Gel-shift and chromatin immunoprecipitation experiments demonstrated that NFI factors are indeed interacting in vitro and in vivo with the binding sequence. These results suggest a NFI role in C2C12 cell differentiation.

Animals↗
PubMed2003

Severe congenital muscular dystrophy in a Mexican family with a new nonsense mutation (R2578X) in the laminin alpha-2 gene.

The congenital muscular dystrophies (CMDs) are a heterogeneous group of autosomal recessive disorders. Approximately one half of cases diagnosed with classic CMD show primary deficiency of the laminin alpha2 chain of merosin. Complete absence of this protein is usually associated with a severe phenotype characterized by drastic muscle weakness and characteristic changes in white matter in cerebral magnetic resonance imaging (MRI). Here we report an 8-month-old Mexican female infant, from a consanguineous family, with classical CMD. Serum creatine kinase was elevated, muscle biopsy showed dystrophic changes, and there were abnormalities in brain MRI. Immunofluorescence analysis demonstrated the complete absence of laminin alpha2. In contrast, expression of alpha-, beta-, gamma-, and delta-sarcoglycans and dystrophin, all components of the dystrophin-glycoprotein complex, appeared normal. A homozygous C long right arrow T substitution at position 7781 that generated a stop codon in the G domain of the protein was identified by mutation analysis of the laminin alpha2 gene ( LAMA2). Sequence analysis on available DNA samples of the family showed that parents and other relatives were carriers of the mutation.

Brain↗
PubMed2003

Endothelial nitric oxide synthase gene polymorphism in the Indian and Mestizo populations of Mexico.

Endothelium-derived nitric oxide (NO) is an important factor in vasodilation synthesized by endothelial nitric oxide synthase (eNOS). A polymorphism (894 G to T) in exon 7 of the eNOS gene causes the conversion of Glu to Asp in position 298. The Glu298Asp polymorphism has been extensively associated with cardiovascular disease. We determined the Glu298Asp polymorphism frequency in healthy Mexican Mestizo, Huastec, Mayo, and Mayan populations by the endonuclease restriction method. The four populations analyzed were in Hardy-Weinberg equilibrium. Allele frequencies were similar among Mexican populations but different when compared with Caucasians. However, when compared with allele frequencies in Asian populations, Mestizo and Huastec allele frequencies were significantly different. Genotypically, only the Mestizos presented Asp298 homozygosity. The absence of double mutants in Indian populations resembles that in Asians. With these data, we conclude that the low frequency of the eNOS Glu298Asp polymorphism in Indian and Mestizo populations of Mexico is related to the Asian origin of Amerindian groups.

Alleles↗
PubMed2002

Identification of novel mutations in the RB1 gene in Mexican patients with retinoblastoma.

Retinoblastoma (RB) is a childhood tumor of the eye with an average incidence of one case in every 15,000-20,000 live births and occurs in sporadic or hereditary form. This cancer results from loss or inactivation of the RB1 gene located at 13q14.1. This gene encodes for a 110 Kd nuclear phosphoprotein (pRB) that plays a major role in cell proliferation control. Different types of mutations in the RB1 gene have been reported, but point mutations are the most common. There are no molecular studies on RB1 gene mutation in Mexican patients. In this study, 19 patients with bilateral or unilateral RB were analyzed. Genetic and cytogenetic studies were carried out. Detection of RB1 gene mutations was done using single-strand conformational polymorphism (SSCP). Five conformational polymorphisms were identified in different exons. In all cases, SSCP sequence showed new non-described mutations that produced a frameshift on the open reading frame. The identification of mutations in the RB1 gene contributes to basic knowledge of this neoplasia and permits the possibility to offer adequate genetic counseling to relatives at risk.

Base Sequence↗
PubMedDate not supplied

Glu298Asp endothelial nitric oxide synthase polymorphism is a risk factor for erectile dysfunction in the Mexican Mestizo population.

Penile erection depends on the balanced action between antagonist vasoactive molecules such as nitric oxide (NO) and angiotensin. Endothelial nitric oxide synthase (eNOS) and angiotensin-converting enzyme (ACE) polymorphisms have been associated with endothelial dysfunction, which is described as a cause of erectile dysfunction (ED). Endothelial NOS and ACE are both regulators of vascular and corporal smooth muscle tone, which are connected by interaction between the NO-cyclic guanosine monophosphate pathway and the renin-angiotensin system. We analyzed the frequencies of 894 G/T (Glu298Asp) eNOS and ACE I/D polymorphisms in Mexican patients with ED (n=53) and in an age-matched control group (n=62). The populations analyzed were in Hardy Weinberg equilibrium. We found significant differences in allelic (chi2=4.42; P=.03) and genotypic frequencies (chi2=3.96; P=.04) between patients and controls for the 894 G/T eNOS polymorphism. Presence of the 894T allele in carriers increased the risk of ED (odds ratio [TT + GT versus GG] = 2.37; 95% confidence interval, 1.08 to 5.21; P=.02). Multiple logistic regression analysis showed that the Glu298Asp polymorphism was an independent factor for ED, as was diabetes mellitus, hypertension, cardiac disease, and cigarette smoking. No association was found between ACE I/D polymorphism and ED in the population studied. Therefore, our results suggest that Glu298Asp eNOS polymorphism plays a role as a genetic susceptibility factor for ED.

Adult↗
PubMedDate not supplied

Gene identification by cDNA arrays in HPV-positive cervical cancer.

BACKGROUND: One of the most frequent malignancies in women worldwide is carcinoma of the uterine cervix. High-risk human papillomavirus (HPV) infection is considered the most important etiological factor of uterine cervical cancer. Our aim was to identify novel cellular genes that could potentially act as predictive molecular markers for human cervical cancer by means of cDNA arrays. METHODS: We used cDNA arrays to examine the expression profiles of six cell lines derived from human cervical cancer, three HPV+ tumor samples and three normal (HPV-) epithelium tissues. Data normalization was performed and the top overexpressed genes were obtained. Hierarchical cluster was performed and, to validate some of the differentially expressed genes between normal and carcinogenic samples, semi-quantitative RT-PCR, in situ hybridization and immunohistochemistry were performed in tissue samples. RESULTS: Four genes were demonstrated to be consistently overexpressed in invasive cervical cancer biopsies; three novel genes not previously related to cervical cancer: MMP10, Lamc2 and Claudin 1. Moreover, overexpression of IL6 and VEGF was corroborated. CONCLUSIONS: The identification of characteristic molecular changes in cervical cells by carcinogenesis and HPV infection can lead to a better understanding of cervical cancer. cDNA arrays are beginning to provide new possible molecular markers for prognosis and diagnosis. This technology could eventually help to elucidate the biological differences of the particular mechanisms associated with each different HPV-type infection and those with a poor prognosis.

Cell Line, Tumor↗