Aptamer-Based Recognition of Breast Tumor Cells: A New Era for Breast Cancer Diagnosis.

Breast cancer is one of the leading causes of death among women worldwide and can be classified into four major distinct molecular subtypes based on the expression of specific receptors. Despite significant advances, the lack of biomarkers for detailed diagnosis and prognosis remains a major challenge in the field of oncology. This study aimed to identify short single-stranded oligonucleotides known as aptamers to improve breast cancer diagnosis. The Cell-SELEX technique was used to select aptamers specific to the MDA-MB-231 tumor cell line. After selection, five aptamers demonstrated specific recognition for tumor breast cell lines and no binding to non-tumor breast cells. Validation of aptamer specificity revealed recognition of primary and metastatic tumors of all subtypes. In particular, AptaB4 and AptaB5 showed greater recognition of primary tumors and metastatic tissue, respectively. Finally, a computational biology approach was used to identify potential aptamer targets, which indicated that CSKP could interact with AptaB4. These results suggest that aptamers are promising in breast cancer diagnosis and treatment due to their specificity and selectivity.

Phase III, randomized, double-blind, placebo-controlled clinical study: a study on the safety and clinical efficacy of AZVUDINE in moderate COVID-19 patients.

Background: In 2019, a highly pathogenic coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surfaced and resulted in the outbreak of coronavirus disease 2019 (COVID-19). With the aim of finding effective drugs to fight against the disease, several trials have been conducted since COVID-19 can only be considered a treatable disease, from a clinical point of view, after the availability of specific and effective antivirals. AZVUDINE (FNC), initially developed for treating HIV, is a potential treatment for COVID-19 as it has the capability to lower the patient's viral load and promote recovery. Methods: Volunteers infected with SARS-CoV-2 confirmed by reverse transcription polymerase chain reaction (RT-PCR), with good kidney and liver function, who were not using other antivirals or monoclonal antibodies were eligible. Samples from patients were assessed for viral load every 48 h during treatment using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and droplet digital polymerase chain reaction (ddPCR). Results: The study's primary outcome measure was the percentage of participants showing an improvement in clinical scores, while the secondary outcome measure was the percentage of participants with a clinical outcome of cure. These measures were used to assess the safety and efficacy of FNC for treating COVID-19. In the analysis of sociodemographic variables, no significant differences were detected between patients in the FNC and the placebo group for race, age group, or sex. The results showed a potential benefit to participants who received FNC during the study, as observed in the shorter hospital stay, shorter negative conversion time of SARS-CoV-2, and a significant reduction in viral load. Furthermore, the reduction in fever and chills were significant at D1, D2, and D3. In this study, a total of 112 adverse events cases were noted, with 105 cases being categorized as non-serious and only 7 cases as serious adverse events. Conclusion: The pandemic is not being effectively controlled and is causing multiple waves of infection that require extensive medical resources. However, FNC has demonstrated potential to reduce the treatment duration of moderate COVID-19 cases, thereby saving significant medical resources. This makes FNC a promising candidate for COVID-19 treatment.Clinical trial registration: [clinicaltrials.gov], identifier [NCT04668235].

Next Generation of Ovarian Cancer Detection Using Aptamers.

Ovarian cancer is among the seven most common types of cancer in women, being the most fatal gynecological tumor, due to the difficulty of detection in early stages. Aptamers are important tools to improve tumor diagnosis through the recognition of specific molecules produced by tumors. Here, aptamers and their potential targets in ovarian cancer cells were analyzed by in silico approaches. Specific aptamers were selected by the Cell-SELEX method using Caov-3 and OvCar-3 cells. The five most frequent aptamers obtained from the last round of selection were computationally modeled. The potential targets for those aptamers in cells were proposed by analyzing proteomic data available for the Caov-3 and OvCar-3 cell lines. Overexpressed proteins for each cell were characterized as to their three-dimensional model, cell location, and electrostatic potential. As a result, four specific aptamers for ovarian tumors were selected: AptaC2, AptaC4, AptaO1, and AptaO2. Potential targets were identified for each aptamer through Molecular Docking, and the best complexes were AptaC2-FXYD3, AptaC4-ALPP, AptaO1-TSPAN15, and AptaO2-TSPAN15. In addition, AptaC2 and AptaO1 could detect different stages and subtypes of ovarian cancer tissue samples. The application of this technology makes it possible to propose new molecular biomarkers for the differential diagnosis of epithelial ovarian cancer.

Mutation profiling in the PIK3CA, TP53, and CDKN2A genes in circulating free DNA and impalpable breast lesions.

Breast impalpable lesions have become a clinical dilemma because they are small, presenting a heterogeneous cellular phenotype. The aim of this study was to evaluate the mutational profile of the PIK3CA, TP53, and CDKN2A genes, comparing the mammary tissue with the respective circulating free DNA (cfDNA). The PIK3CA, TP53, and CDKN2A genes were sequenced (PCR-Sanger) in 58 women with impalpable lesions (49 malignant and 9 benign) with the respective cfDNA. The chi-square or Fisher's exact test was used to evaluate statistical significance between the clinical variables and mutational profile. A total of 51 out of 58 samples generated successful mutation profiles in both breast lesion and cfDNA. Of the 37 mutations detected, 10 (27%) and 16 (43%) mutations were detected in benign and malignant breast lesions, respectively, while 2 (5%) and 9 (24%) were found in cfDNA of women with benign and malignant lesions, respectively. The lymph node involvement with mutations in the PIK3CA in malignant lesions (P = 0.001), and the relationship between mutations in PIK3CA, comparing ductal tumors with benign lesions (P = 0.05), were statistically significant. This study detected different mutations in PIK3CA, TP53, and CDKN2A genes, which represent, in part, the heterogeneity of impalpable lesions. The results confirm that more studies should be conducted on the functional role of cfDNA in the impalpable lesions.

TGF-ß Polymorphisms Are a Risk Factor for Chagas Disease.

Transforming growth factor ß1 (TGF-ß1) is an important mediator in Chagas disease. Furthermore, patients with higher TGF-ß1 serum levels show a worse clinical outcome. Gene polymorphism may account for differences in cytokine production during infectious diseases. We tested whether TGFB1 polymorphisms could be associated with Chagas disease susceptibility and severity in a Brazilian population. We investigated five single-nucleotide polymorphisms (-800 G>A, -509 C>T, +10 T>C, +25 G>C, and +263 C>T). 152 patients with Chagas disease (53 with the indeterminate form and 99 with the cardiac form) and 48 noninfected subjects were included. Genotypes CT and TT at position -509 of the TGFB1 gene were more frequent in Chagas disease patients than in noninfected subjects. Genotypes TC and CC at codon +10 of the TGFB1 gene were also more frequent in Chagas disease patients than in noninfected subjects. We found no significant differences in the distribution of the studied TGFB1 polymorphisms between patients with the indeterminate or cardiac form of Chagas disease. Therefore, -509 C>T and +10 T>C TGFB1 polymorphisms are associated with Chagas disease susceptibility in a Brazilian population.

Effect of selection for eventing on the MSTN gene in Brazilian sport horses.

Polymorphisms in MSTN have previously been associated with equine performance. Therefore, the aim of this study was to identify variants in MSTN intron 1 in 16 Brazilian Sport Horses selected for competition in eventing and their possible effects of selection on performance. Among the nine variants identified, eight had already been reported in previous studies or genomic databases, although they showed differences in frequencies when compared with other horse breeds. Moreover, a new mutation was identified in two horses, both in heterozygous form. Considering the absence of molecular studies in this valuable Brazilian breed, these findings represent an important contribution to the characterization of its genetic profile and may possibly aid in further genotype-phenotype association studies.

Screening of mutations in the additional sex combs like 1, transcriptional regulator, tumor protein p53, and KRAS proto-oncogene, GTPase/NRAS proto-oncogene, GTPase genes of patients with myelodysplastic syndrome.

Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal bone marrow disorders characterized by ineffective hematopoiesis, different degrees of cellular dysplasia, and increased risk of progression to acute myeloid leukemia. International Prognostic Scoring System is the gold standard for MDS classification; however, patients exhibiting different clinical behaviors often coexist in the same group, indicating that the currently available scoring systems are insufficient. The genes that have recently been identified as mutated in MDS, including additional sex combs like 1, transcriptional regulator (ASXL1), tumor protein p53 (TP53), and KRAS proto-oncogene and GTPase (KRAS)/NRAS proto-oncogene, GTPase (NRAS), may contribute to a more comprehensive classification, as well as to the prognosis and progression of the disease. In the present study, the mutations in the ASXL1, TP53 and NRAS/KRAS genes in 50 patients were evaluated by sequencing genomic bone marrow DNA. Nine patients (18%) presented with at least one type of mutation. Mutations in TP53 were the most frequent in six patients (12%), followed by ASXL1 in two patients (4%) and NRAS in one patient (2%). The nine mutations were detected in patients with low- and high-risk MDS. The screening of mutations in MDS cases contributes to the application of personalized medicine.

Health survey and assessment of the polymorphisms BRCA1/P871L, BRCA1/Q356R, and BRCA2/N372H in female gas station workers in Rio de Janeiro.

Gas station workers are exposed to chemicals known to be carcinogenic, especially benzene. The objective was to analyze the health problems of female gas station workers by means of sociodemographic and clinical questionnaires, and laboratorial exams. We performed the genotyping of the polymorphisms BRCA1/P871L and BRCA1/Q356R by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism, and of variant allele BRCA2/N372H through direct sequencing. The female workers showed a higher concentration of monocytes (P = 0.039); a greater number of spontaneous abortions (P = 0.025, OR = 4.977, 95% CI = 1.135-30.669); higher tobacco consumption (P = 0.013); and higher alcohol consumption (P = 0.05). The statistical analysis of the polymorphisms associated with the variables monocyte concentration and miscarriage number did not reveal a significant relationship, and smoking and spontaneous abortion were not statistically associated either. Environ. Mol. Mutagen. 58:730-734, 2017. © 2017 Wiley Periodicals, Inc.

Impact of reduced levels of APE1 transcripts on the survival of patients with urothelial carcinoma of the bladder.

Molecular evidence indicates that alterations in genes involved in the maintenance of genome stability may be related to susceptibility to bladder carcinoma. Our goal was to evaluate the prognostic role of base excision repair (BER) genes in a cohort of patients diagnosed with primary urothelial carcinoma of the bladder (UCB). The levels of all APE1, XRCC1 and POLB transcripts were detected by quantitative real-time PCR (qPCR) technique in tumor samples from 52 patients undergoing transurethral resection (TUR) for primary UCB at the Department of Urology, Brazilian National Cancer Institute, Rio de Janeiro. Increased levels of APE1, XRCC1 and POLB transcripts were significantly associated with high-grade tumors when compared to these levels in low-grade tumors (p<0.01) and could be attributed to different mechanisms of transcriptional regulation as a response to tumorigenesis and oxidative stress. By analyzing the collected data in the present study, regardless of pathological grade or stage, univariate analysis revealed that the reduced levels of APE1 transcripts were significantly associated with cancer-specific mortality (p=0.032). Furthermore, the variant genotype (TG/GG) of the APE1 T1349G polymorphism was observed in 75% of a subset of patients who concomitantly experienced reduced levels of the APE1 transcript and death and/or recurrence events. Taken together, our data reinforce the idea that human DNA repair mechanisms must be finely regulated in order to avoid instability leading to tumorigenesis and poor clinical outcomes in UCB patients.

CDKN2A (p14(ARF)/p16(INK4a)) and ATM promoter methylation in patients with impalpable breast lesions.

Early detection of breast cancer increases the chances of cure, but the reliable identification of impalpable lesions is still a challenge. In spite of the advances in breast cancer detection, the molecular basis of impalpable lesions and the corresponding circulating biomarkers are not well understood. Impalpable lesions, classified by radiologists according to the Breast Imaging Reporting and Data System in the categories 3 and 4, can be either benign or malignant (slow growing or aggressive). In this article, we report the DNA methylation pattern in CDKN2A (p14(ARF)/p16(INK4a)) and in ATM gene promoters from 62 impalpable lesions, 39 peripheral blood samples, and 39 saliva samples, assessed by methylation-specific polymerase chain reaction method. ATM showed the greatest percentage of methylation in DNA from lesions (benign and malignant), blood (even with p16(INK4a)), and saliva, followed by p16(INK4a) and p14(ARF). Among the malignant cases, ATM promoter was the most hypermethylated in lesion DNA and in blood and saliva DNAs, and p14(ARF), the least. The highest percentage of p16(INK4a) methylation was found in the blood. Finally, our data are relevant because they were obtained using impalpable breast lesions from patients who were carefully recruited in 2 public hospitals of Rio de Janeiro.

Human glutathione S-transferase polymorphisms associated with prostate cancer in the Brazilian population.

OBJECTIVE: To evaluate the influence of polymorphisms in GSTA1, GSTM1, GSTT1, and GSTP1 in the risk of developing Prostate Cancer (PCa) in a population of Rio de Janeiro and compare the distribution of allele and genotype frequencies of the polymorphisms analyzed in the present study population with other regions in the country and different ethnic groups. MATERIALS AND METHODS: We analyzed a sample of the Brazilian population, comprising 196 patients with PCa treated by the urology services of the Brazilian National Cancer Institute (INCA) and Mario Kroeff Hospital (HMK), and 208 male blood donors from the Clementino Fraga Filho Hospital, Federal University of Rio de Janeiro (UFRJ). The polymorphisms were determined in DNA, extracted from peripheral blood leucocytes using the Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP). RESULTS: Our results showed that the distribution of polymorphisms can vary significantly according to the Brazilian region and ethnic groups. The distribution of allele and genotype frequencies of the polymorphism GSTA1 was statistically different between cases and controls. Genotypes (A / B + B / B) were associated with protection (OR = 0.61, 95% CI = 0.40-0.92) for PCa in comparison to genotype A / A. CONCLUSION: The distribution of genotype frequencies of the polymorphism GSTA1 was statistically different between the case and control groups (p = 0.023), and the presence of genotypes A / B and B / B suggests a protective role against the risk of PCa compared to genotype A / A. This is the first study that reports the genotypic frequency of this polymorphism and its association with PCa in a Brazilian population sample.

Human glutathione S-transferase polymorphisms associated with prostate cancer in the Brazilian population

Objective To evaluate the influence of polymorphisms in GSTA1, GSTM1, GSTT1, and GSTP1 in the risk of developing Prostate Cancer (PCa) in a population of Rio de Janeiro and compare the distribution of allele and genotype frequencies of the polymorphisms analyzed in the present study population with other regions in the country and different ethnic groups. Materials and Methods We analyzed a sample of the Brazilian population, comprising 196 patients with PCa treated by the urology services of the Brazilian National Cancer Institute (INCA) and Mario Kroeff Hospital (HMK), and 208 male blood donors from the Clementino Fraga Filho Hospital, Federal University of Rio de Janeiro (UFRJ). The polymorphisms were determined in DNA, extracted from peripheral blood leucocytes using the Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP). Results Our results showed that the distribution of polymorphisms can vary significantly according to the Brazilian region and ethnic groups. The distribution of allele and genotype frequencies of the polymorphism GSTA1 was statistically different between cases and controls. Genotypes (A / B + B / B) were associated with protection (OR = 0.61, 95 % CI = 0.40-0.92) for PCa in comparison to genotype A / A. Conclusion The distribution of genotype frequencies of the polymorphism GSTA1 was statistically different between the case and control groups (p = 0.023), and the presence of genotypes A / B and B / B suggests a protective role against the risk of PCa compared to genotype A / A. This is the first study that reports the genotypic frequency of this polymorphism and its association with PCa in a Brazilian population sample. .

Identification of Mycobacterium tuberculosis complex based on amplification and sequencing of the oxyR pseudogene from stored Ziehl-Neelsen-stained sputum smears in Brazil.

A cross-sectional analysis of stored Ziehl-Neelsen (ZN)-stained sputum smear slides (SSS) obtained from two public tuberculosis referral laboratories located in Juiz de Fora, Minas Gerais, was carried out to distinguish Mycobacterium bovis from other members of the Mycobacterium tuberculosis complex (MTC). A two-step approach was used to distinguish M. bovis from other members of MTC: (i) oxyR pseudogene amplification to detect MTC and, subsequently, (ii) allele-specific sequencing based on the polymorphism at position 285 of this gene. The oxyR pseudogene was successfully amplified in 100 of 177 (56.5%) SSS available from 99 individuals. No molecular profile of M. bovis was found. Multivariate analysis indicated that acid-fast bacilli (AFB) results and the source laboratory were associated (p < 0.05) with oxyR pseudogene amplification. SSS that were AFB++ SSS showed more oxyR pseudogene amplification than those with AFB0, possibly due to the amount of DNA. One of the two source laboratories presented a greater chance of oxyR pseudogene amplification, suggesting that differences in sputum conservation between laboratories could have influenced the preservation of DNA. This study provides evidence that stored ZN-SSS can be used for the molecular detection of MTC.

Identification of Mycobacterium tuberculosis complex based on amplification and sequencing of the oxyR pseudogene from stored Ziehl-Neelsen-stained sputum smears in Brazil

A cross-sectional analysis of stored Ziehl-Neelsen (ZN)-stained sputum smear slides (SSS) obtained from two public tuberculosis referral laboratories located in Juiz de Fora, Minas Gerais, was carried out to distinguish Mycobacterium bovis from other members of the Mycobacterium tuberculosis complex (MTC). A two-step approach was used to distinguish M. bovis from other members of MTC: (i) oxyR pseudogene amplification to detect MTC and, subsequently, (ii) allele-specific sequencing based on the polymorphism at position 285 of this gene. The oxyR pseudogene was successfully amplified in 100 of 177 (56.5 percent) SSS available from 99 individuals. No molecular profile of M. bovis was found. Multivariate analysis indicated that acid-fast bacilli (AFB) results and the source laboratory were associated (p < 0.05) with oxyR pseudogene amplification. SSS that were AFB++ SSS showed more oxyR pseudogene amplification than those with AFB0, possibly due to the amount of DNA. One of the two source laboratories presented a greater chance of oxyR pseudogene amplification, suggesting that differences in sputum conservation between laboratories could have influenced the preservation of DNA. This study provides evidence that stored ZN-SSS can be used for the molecular detection of MTC.

Prognostic relevance of KIT and PDGFRA mutations in gastrointestinal stromal tumors.

BACKGROUND: Prediction of biological behavior is crucial for selection of new therapeutic modalities in GIST. Here, we aimed to assess whether KIT and PDGFRA mutations have survival impact in gastrointestinal stromal tumors (GIST). PATIENTS AND METHODS: Fifty-five Brazilian patients with completely resected GIST were examined for KIT and PDGFRA mutations. The 5-year disease-free survival (DFS) was analyzed. RESULTS: KIT and PDGFRA mutations were identified in 74.5% and 7.3% of patients, respectively. The 5-year DFS rate for all patients was 52.8%. The 5-year DFS rate was lower in patients with tumors having in-frame deletions or concomitant in-frame deletions and insertions affecting codons 557-558 than in patients with tumors having other exon 11 KIT mutations (p=0.023). Conversely, when the patients with concomitant deletion-insertion mutations affecting codons 557-558 were excluded from the analysis, deletions involving codons 557-558 had no influence on 5-year DFS rates. CONCLUSION: Our findings indicate that a specific KIT mutation may be associated with unfavorable behavior in GIST. This finding may have implications on selecting patients for adjuvant therapy.

Identification and characterization of novel sequence variations in MECP2 gene in Rett syndrome patients.

Rett syndrome (RS) is a neurodevelopmental disorder caused by mutations in MECP2 gene. Exons 2, 3, and 4, in addition to intronic and 3'UTR adjacent regions, were sequenced in 80 patients with RS. Twenty-nine sequence variations were detected in 49 patients, 34 (69.4%) patients with the classic form of RS, and 15 (30.6%) patients with atypical forms of RS. Thirteen of the 29 detected mutations represent novel sequence variations. Missense mutation T158M was the most commonly observed mutation, detected in nine patients (11.2%). Six hotspot pathogenic mutations (R133C, T158M, R168X, R255X, R270X, and R294X) were responsible for the phenotype in 26/80 patients (32.5%).