RESUMO

Gastric cancer (GC) is the fourth leading cause of cancer death in the world, and there is a demand for new therapeutic agents to treat GC. Metformin has been demonstrated to be an antineoplastic agent in some types of cancer; however, it has not been sufficiently valued in treating GC because the effect of metformin in combination with chemotherapy regimens has not yet been evaluated. The present study aimed to evaluate the mechanisms underlying cell death induced by metformin alone or when combined with chemotherapy. The cytogenetic characteristics of the NCI-N87 cell line were determined by fluorescence in situ hybridization (FISH). To determine viability, the cells were treated with metformin, epirubicin, cisplatin, docetaxel and 5-fluorouracil (individually and at different concentrations). Subsequently, the cells were treated with metformin alone, and in combination with the chemotherapeutic drugs and the epirubicin + cisplatin + 5-fluorouracil, docetaxel + cisplatin + 5-fluorouracil, and cisplatin + 5-fluorouracil regimens. Cell viability, proliferation and mitochondrial membrane potential (ΔΨm) were analyzed by spectrophotometry. Apoptosis, caspase activity and cell cycle progression were assessed by flow cytometry. Finally, light microscopy was used to evaluate senescence and clonogenicity. The results revealed that metformin, alone and when combined with chemotherapy, increased the proportion of apoptotic cells, promoted the loss of ΔΨm, and induced apoptosis through caspase activity in GC cells. Moreover, metformin decreased cell proliferation. In addition, metformin alone did not induce senescence and it counteracted the effects of chemotherapy-induced senescence in GC cells. Additionally, metformin, alone and when combined with chemotherapy, decreased the clonogenic capacity of NCI-N87 GC cells. In conclusion, metformin may increase the effects of chemotherapy on NCI-N87 cell death and could represent an option to improve the treatment of GC.

RESUMO

INTRODUCTION: In Mexico, familial hypercholesterolemia (FH) is underdiagnosed, but population screening in small communities where at least one homozygous patient has already been detected results in a useful and inexpensive approach to reduce this problem. Considering that we previously reported nine homozygous cases from the state of Oaxaca, we decided to perform a population screening to identify patients with FH and to describe both their biochemical and genetic characteristics. METHODS: LDL cholesterol (LDLc) was quantified in 2,093 individuals from 11 communities in Oaxaca; either adults with LDLc levels ≥170 mg/dL or children with LDLc ≥130 mg/dL were classified as suggestive of FH and therefore included in the genetic study. LDLR and APOB (547bp fragment of exon 26) genes were screened by sequencing and MLPA analysis. RESULTS: Two hundred and five individuals had suggestive FH, with a mean LDLc of 223 ± 54 mg/dL (range: 131-383 mg/dL). Two pathogenic variants in the LDLR gene were detected in 149 individuals: c.-139_-130del (n = 1) and c.2271del (n = 148). All patients had a heterozygous genotype. With the cascade screening of their relatives (n = 177), 15 heterozygous individuals for the c.2271del variant were identified, presenting a mean LDLc of 133 ± 35 mg/dL (range: 60-168 mg/dL). CONCLUSIONS: The FH frequency in this study was 7.8% (164/2093), the highest reported worldwide. A founder effect combined with inbreeding could be responsible for the high percentage of patients with the LDLR c.2271del variant (99.4%), which allowed us to detect both significant biochemical heterogeneity and incomplete penetrance; hence, we assumed the presence of phenotype-modifying variants.

Assuntos

RESUMO

BACKGROUND: High expression of the Cytokine Receptor-Like Factor 2 (CRLF2) gene has been observed in patients with acute lymphoblastic leukemia BCR-ABL1-like subtype. Currently, there is no commercial system available for the direct detection of the IGH::CRLF2 fusion by fluorescent in situ hybridization (FISH), as there are for many other leukemia-related gene fusions. In an effort to verify the IGH::CRLF2 fusion, some researchers prepare home-grown FISH probes from bacterial artificial chromosome clones flanking the IGH and CRLF2 genes, which is the best alternative to confirm the fusion, however difficult to reproduce in most cytogenetic laboratories. RESULTS: For the direct observation of the IGH::CRLF2 gene fusion we designed a methodological approach requiring the two commercially available IGH and CRLF2 break-apart probes. CONCLUSIONS: Our methodological approach allows direct visualization of the IGH::CRLF2 gene fusion and has the potential to be used for identification of other gene fusions.

RESUMO

APOB gene polymorphisms are considered risk factors for the development of dyslipidemia, hypertension, and cardiovascular disease (CVD) in several populations. In Mexico, these pathologies are frequent and studies regarding this gene are scarce. The aim of this cross-sectional study was to determined genotype, allele, and haplotype frequencies of APOB polymorphisms and performed analyses of association among the biochemical, hemodynamic, anthropometrical, and genetic variables. Blood samples were taken from 361 subjects from unselected Mexican population for biochemical analysis and for deoxyribonucleic acid extraction; besides blood pressure and body mass index (BMI) were measured. APOB polymorphisms rs934197, rs533617, rs693, and rs1042031 were genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism; whereas, rs17240441 and c.66_67insCTGCTG were genotyped by PCR followed by electrophoresis. Genotype and allele frequencies were obtained by simple counting and deviations from Hardy-Weinberg equilibrium (HWE) were calculated by chi-square test. The effect of the polymorphisms on the quantitative variables was determined using analysis of variance, Student's t test, Pearson's and Spearman's correlations and multiple linear regression models. All the polymorphisms were within HWE. Frequencies of mutated alleles were highly heterogeneous: rs934197-T 33.6%, rs17240441-D 39.3%, c.66_67insCTGCTG-I 3.9%, rs533617-G 0.9%, rs693-T 40.5%, and rs1042031-G 17.3%. Chronic degenerative diseases were frequent in the studied population: overweight-obesity 55.1%, dyslipidemia 45.8%, and hypertension 23.5%. The association analyses showed that despite adjustments for age and sex the mutated alleles rs934197-T, rs1042031G, c.66_67-insCTGCTG-I, and rs533617-G, were related to lower values of BMI, total cholesterol (TC), systolic blood pressure, and diastolic blood pressure, respectively. All polymorphisms analyzed except rs533517 and c.66_67insCTGCTG showed high frequencies of the mutated allele, making them useful for association studies. Our results revealed that, APOB gene polymorphisms could be contributing to the development of several chronic diseases, such as essential hypertension, dyslipidemias, obesity, among others. However, specific studies with each pathology are needed to know the possible implications of the polymorphisms.

Assuntos

RESUMO

Acute promyelocytic leukemia (APL) is characterized by the chromosomal translocation t(15;17)(q24;q21), raising two hybrid genes: PML::RARA and RARA::PML. There is a biased clonal evolution in APL since imbalances affecting the der(15) chromosome (the one that carries the transforming PML::RARA gene) have never been reported; instead, imbalances of the der(17), mainly in form of an ider(17)(q10), have been repeatedly documented. We here present two cases with APL who acquired an ider(17)(q10) as a secondary chromosomal change. The presence of the ider(17)(q10) implies several genomic consequences with potential to fuel tumor progression: (1) a duplication of the hybrid gene RARA::PML; (2) a cumulative haploinsufficiency for tumor suppressor genes located in the 17p arm; and (3) a cumulative triplosensitivity of genes located in 17q10→RARA::PML→15qter. Both our patients were treated following the PETHEMA LPA 2012 protocol with ATRA plus idarubicin and they have had a long event-free survival.

Assuntos

RESUMO

Primary hypertriglyceridemia (PHTG) is characterized by a high concentration of triglycerides (TG); it is divided between familial hyperchylomicronemia syndrome and multifactorial chylomicronemia syndrome. In Mexico, hypertriglyceridemia constitutes a health problem in which the genetic bases have been scarcely explored; therefore, our objective was to describe biochemical-clinical characteristics and variants in the APOA5, GPIHBP1, LMF1, and LPL genes in patients with primary hypertriglyceridemia. Thirty DNA fragments were analyzed using PCR and Sanger sequencing in 58 unrelated patients. The patients' main clinical-biochemical features were hypoalphalipoproteinemia (77.6%), pancreatitis (18.1%), and a TG median value of 773.9 mg/dL. A total of 74 variants were found (10 in APOA5, 16 in GPIHBP1, 34 in LMF1, and 14 in LPL), of which 15 could be involved in the development of PHTG: 3 common variants with significative odds and 12 heterozygous rare pathogenic variants distributed in 12 patients. We report on the first Mexican patient with hyperchylomicronemia syndrome due to GPIHBP1 deficiency caused by three variants: p.R145*, p.A154_G155insK, and p.A154Rfs*152. Moreover, eleven patients were heterozygous for the rare variants described as causing PHTG and also presented common variants of risk, which could partially explain their phenotype. In terms of findings, two novel genetic variants, c.-40_-22del LMF1 and p.G242Dfs*10 LPL, were identified.

Assuntos

RESUMO

BACKGROUND: 4q deletion syndrome is a rare chromosomal disorder that mostly arises de novo. The syndrome is characterized by craniofacial dysmorphism, digital abnormalities, skeletal alterations, heart malformations, developmental delay, growth retardation, Pierre Robin sequence, autistic spectrum and attention deficit-hyperactivity disorder, although not every patient shows the same features. Array comparative genomic hybridization (aCGH) use improves the detection of tiny chromosomal deletions and allows for a better understanding of genotype-phenotype correlations in affected patients. We report the case of a 6-year-old female patient showing mild dysmorphic features, mild mental disabilities and a coagulation disorder as a consequence of a de novo del(4)(q34.1) characterized by aCGH. CASE PRESENTATION: A 6-year-old female patient exhibited special craniofacial features, such as backward-rotated ears, upslanted palpebral fissures, broad nasal bridges, anteverted nares, broad nasal alae, smooth philtrums, smooth nasolabial folds, thin lips, horizontal labial commissures, and retrognathia. In the oral cavity, maxillary deformation, a high arched palate, agenesis of both mandibular canines and fusion of two mandibular incisors were observed. She also displayed bilateral implantation of the proximal thumbs, widely spaced nipples, dorsal kyphosis, hyperlordosis, and clitoral hypertrophy. In addition, the patient presented with coagulopathy, psychomotor delay, attention deficit-hyperactivity disorder, and mild mental disability. A chromosomal study showed the karyotype 46,XX,del(4)(q34.1), while an aCGH analysis revealed an 18.9 Mb deletion of a chromosome 4q subtelomeric region spanning 93 known genes. CONCLUSION: The clinical manifestations of this patient were similar to those reported in other individuals with 4q deletion syndrome. Although most of the patients with a 4q34 terminal deletion share similarities, variations in phenotype are also common. In general, clinical effects of chromosomal deletion syndromes depend on the length of the deleted chromosomal segment and, consequently, on the number of lost genes; however, in all of these syndromes, there is no simple correlation between the phenotype and the chromosomal region involved, particularly in cases of 4q deletion.

RESUMO

BACKGROUND: Our aims were to describe the first Mexican patient with abetalipoproteinemia and to perform a comparative analysis of biochemical, clinical, and genetic characteristics of 100 cases reported in the literature. METHODS: We performed biochemical and molecular screenings in a Mexican girl with extremely low lipid levels and in her family. Further, we integrated and evaluated the characteristics of the cases with abetalipoproteinemia described in the literature. RESULTS: Our patient is a six-year-old girl who presented vomiting, chronic diarrhea, failure to thrive, malabsorption, acanthocytosis, anemia, transaminases elevation, and extremely low lipid levels. MTTP gene sequencing revealed homozygosity for a novel mutation p.Gly417Valfs*12 (G deletion c.1250). With the analysis of the reported cases, 60 clinical features (14 classical and 46 non-classical) were observed, being the most common acanthocytosis (57.5%), malabsorption (43.7%), and diarrhea (42.5%); 48.8% of the patients presented only classic clinical features, while the remaining 51.2% developed secondary effects due to a fat-soluble vitamin deficiency. An odds ratio analysis disclosed that patients diagnosed after 10 years of age have an increased risk for presenting clinical complications (OR = 18.0; 95% CI 6.0-54.1, p < 0.0001). A great diversity of mutations in MTTP has been observed (n = 76, being the most common p.G865X and p.N139_E140) and some of them with possible residual activity. CONCLUSION: The first Mexican patient with abetalipoproteinemia presents a novel MTTP mutation p.Gly417Valfs*12. Three factors that could modulate the phenotype in abetalipoproteinemia were identified: age at diagnosis, treatment, and the causal mutation.

Assuntos

RESUMO

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disease characterized by an increased LDL-cholesterol (LDLc) serum concentration and premature cardiovascular disease. Screening of small populations where at least one homozygous (HoFH) patient has been identified may be a proper approach for detecting FH patients. Previously, we reported an HoFH patient carrying the mutation p.Asp360His LDLR, who was born in the Mexican community El Triunfo (Quimixtlan, Puebla). AIM OF THE STUDY: To identify patients with familial hypercholesterolemia in the community El Triunfo and to describe their clinical and biochemical characteristics. METHODS: We studied 308 individuals by quantifying lipid levels and by DNA sequencing. RESULTS: Sixteen of 308 individuals presented an LDLc level >170 mg/dL and all of them turned out to be heterozygous for the LDLR p.Asp360His variant. Subsequently, 34 of their first-degree relatives (mainly siblings and parents) were genotyped rendering six additional HeFH patients, which resulted in 22 carriers of the mutated allele. The study of six LDLR polymorphisms in four unrelated individuals from the community (one HoFH and three HeFH) showed the same haplotype combination, suggesting a unique ancestral origin of the mutation. CONCLUSIONS: The community El Triunfo, has the highest worldwide frequency ever reported of HeFH, with 7.14% (22/308, equivalent to 1/14 inhabitants). Since the HeFH patients showed variable biochemical expression, we suggest looking for factors with the potential to modify the phenotype. Finally, we stress the importance of establishing accurate LDLc cut-off points applicable to Mexican population for the diagnosis of FH.

Assuntos

RESUMO

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disorder that causes accumulation of serum low-density lipoprotein cholesterol and premature cardiovascular disease. It is mainly related to mutations in the LDLR gene. Homozygous FH (HoFH) patients have the most severe form of the disease accounting for a worldwide prevalence of 1:1,000,000. In Mexico, at least 5 cases of HoFH have been reported. OBJECTIVE: The aim of this study was to describe the clinical, biochemical, and molecular data observed in patients with HoFH phenotype. METHODS: We included 13 patients, belonging to 11 families, with clinical and biochemical diagnoses suggestive of HoFH. Molecular analyses of the LDLR and APOB genes were performed by means of polymerase chain reaction followed by Sanger sequencing. RESULTS: The causal mutation of HoFH was found in 8 of 11 unrelated patients. Excepting 1, all were true homozygotes. Six different variants in LDLR were identified: c.-139delCTCCCCCTGC, p.Glu140Lys, p.Asp360His, p.Asn405Lys, p.Ala755Glyfs*7, and p.Leu759Serfs*6. Of these, p.Asp360His and p.Asn405Lys were detected for the first time in Mexico; p.Leu759Serfs*6 showed to be the most frequent (43.7% of the alleles 7/16), and c.-139delCTCCCCCTGC is a new variant located in the promoter region. CONCLUSIONS: This work increases knowledge of biochemical and genetic features in Mexican patients with HoFH. A novel mutation in the LDLR gene promoter was detected: c.-139delCTCCCCCTGC, which possibly inhibits its expression.

Assuntos