Publications by authors named "Leticia B A Rangel"

Ovarian cancer is the second most common malignant neoplasm of gynecological origin and the leading cause of death from cancer in the female reproductive system worldwide. This scenario is largely due to late diagnoses, often in advanced stages, and the development of chemoresistance by cancer cells. These challenges highlight the need for alternative treatments, with immunotherapy being a promising option.

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Background: Breast cancer (BC) is the second most frequent type of cancer in the world and most common among women, configuring a major challenge to global health. BC is a complex and heterogeneous disease that can be subdivided into distinct tumor types based on the expression of molecular markers predicting patient outcomes and response to therapy. A growing number of studies have tried to expand the known markers by investigating the association of altered lipid metabolism with BC immune escape, progression, and metastasis.

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Background: Acquired treatment resistance is a significant problem in breast cancer management, and alterations in lipid metabolism have been proposed to contribute to the development of drug resistance as well as other aspects of tumor progression. The present study aimed to identify the role of cholesterol metabolism in MCF-7 and MDA-MB-231 breast cancer cell response to cisplatin (CDDP) treatment in the acute setting and in a model of CDDP resistance.

Methods: MCF-7 (luminal A), MDA-MB-231 (triple-negative) and CDDP-resistant MDA-MB-231 (MDACR) cell lines were grown in the presence or absence of CDDP in combination with atorvastatin (ATV), lipid depletion or low-density lipoprotein loading and were analyzed by a variety of biochemical and radiometric techniques.

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In this study, eight naphthoquinone derivatives were synthesized in yields ranging from 52 to 96% using easy, fast, and low-cost methodologies. All naphthoquinone derivatives were screened for their in vitro anti-proliferative activities against OVCA A2780 cancer cell lines. Amongst all analysed compounds, derivatives 3-5 presented the most prominent cytotoxic potential.

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cDNA microarray data conducted by our group revealed overexpression of CXCL2 and CXCL8 in ovarian cancer (OC) microenvironment. Herein, we have proven that the chemokine receptor, CXCR2, is a pivotal molecule in re-sensitizing OC to cisplatin, and its inhibition decreases cell proliferation, viability, tumor size in cisplatin-resistant cells, as well as reversed the overexpression of mesenchymal epithelium transition markers. Altogether, our study indicates a central effect of CXCR2 in preventing tumor progression, due to acquisition of cisplatin chemoresistant phenotype by tumor cells, and patients' high lethality rate.

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Osteopontin (OPN) is upregulated in several types of tumor and has been associated with chemoresistance. However, the contribution of OPN splicing isoforms (OPN‑SIs) to chemoresistance requires further investigation. The present study aimed to evaluate the expression patterns of each tested OPN‑SI in cisplatin (CDDP)‑resistant ovarian carcinoma cell lines, focusing on the role of the OPN‑c isoform (OPNc) in drug resistance.

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The growth of the elderly population is a worldwide phenomenon and it is associated with chronic diseases, including dementia. In this scenario, the present study aimed to evaluate a possible association of estrogen receptor α polymorphisms with dementia in a Brazilian cohort. The subject sample was divided into two groups, control ( = 105) and case ( = 73), according to analysis of two predictive dementia tests (MMSE and CDR).

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Purpose: BRCA1 pathogenic variant heterozygotes are at a substantially increased risk for breast and ovarian cancer. The widespread uptake of testing has led to a significant increase in the detection of missense variants in BRCA1, the vast majority of which are variants of uncertain clinical significance (VUS), posing a challenge to genetic counseling. Here, we harness a wealth of functional data for thousands of variants to aid in variant classification.

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Background: Nucleus accumbens-associated protein 1 (NAC1) has multifaceted roles in cancer pathogenesis and progression, including the development of drug resistance, promotion of cytokinesis, and maintenance of "stem cell-like" phenotypes. NAC1 is a transcriptional co-regulator belonging to the bric-a-brac tramtrack broad (BTB) family of proteins, although it lacks the characteristic DNA binding motif of the BTB family. The formation of higher-order transcription complexes likely depends on its interaction with other DNA-binding co-factors.

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Background/aims: Tributyltin (TBT) is an organotin (OTs) and biohazard organometallic pollutant. Recently our group has shown that TBT, even in very low doses, has deleterious effects on several tissues most likely due to its role as an endocrine-disrupting molecule. Other studies have confirmed that OT exposure could be responsible for neural, endocrine, and reproductive dysfunctions via in vitro and in vivo models.

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Background/aims: Osteoporosis is a bone metabolic disease that affects mostly post-menopausal women. There has been shown that vitamin K (VK) supplementation during menopause may decrease bone loss as well as risk of bone breaking. Aiming to clarify the beneficial role of VK in bone metabolism during menopause, we investigated mineral metabolism and bone ultrastructure of ovariectomized (OVX) mice.

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Background: Epithelial ovarian cancer (EOC) remains the most lethal gynecologic malignancy. Primary cytoreductive surgery with adjuvant taxane-platinum chemotherapy is the standard treatment to fight ovarian cancer, however, their side effects are severe, and chemoresistance emerges at high rates. Therefore, EOC clinic urges for novel treatment strategies to reverse chemoresistance and to improve the survival rates.

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Osteoporosis is one of the major diseases that affects mostly postmenopausal women. Despite being a multifactorial disease, some genes have been shown to play an important role in osteoporosis. Bone mineral density (BMD) is still largely used to diagnose it, although many other biomarkers are used to better follow the disease onset.

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Article Synopsis
  • Estrogen plays a crucial role in regulating various functions in the female body, particularly in lipid metabolism and breast cancer.
  • The study investigated two specific SNPs in the ESR1 gene and their effects on lipid levels and breast cancer incidence in post-menopausal Brazilian women over five years.
  • Findings indicated that while one SNP (PvuII) was linked to lower body fat and lower breast cancer rates, the other (XbaI) was associated with higher triglyceride levels and a greater incidence of breast cancer in homozygous patients.
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Ethnic differences in patient genetics and breast cancer (BC) biology contribute to ethnic disparities in cancer presentation and patient outcome. We prospectively evaluated SNPs within phase I and phase II tamoxifen (TAM) metabolizing enzymes, and the estrogen receptor gene (ESR1), aiming to identify potential pharmacogenomic ethnicity patterns in an ER-positive BC cohort constituted of Hispanic and Non-Hispanic White (NHW) women in South Texas. Plasma concentrations of TAM/metabolites were measured using HPLC.

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There are several risk factors related to Breast Cancer (BC) risks and response to chemotherapy with SERMs. Recently some single nucleotide polymorphisms (SNPs) on ESR1 gene have been associated to this disease. However, data are still inconclusive.

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Objective: To test the effectiveness of combining conventional antineoplastic drugs (cisplatin and etoposide) with metformin in the treatment of non-small cell lung cancer in the NCI-H460 cell line, in order to develop new therapeutic options with high efficacy and low toxicity.

Methods: We used the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and calculated the combination index for the drugs studied.

Results: We found that the use of metformin as monotherapy reduced the metabolic viability of the cell line studied.

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Breast cancer (BC) hormonal receptors status is assessed by immunohistochemistry (IHC), a specific, sensitive, and accessible method that guide breast cancer treatment. In this study, we evaluated progesterone receptor (PR) expression in 53 BC cases using 3 anti-PgR antibodies (AB): monoclonal (SP42 and PgR636) and polyclonal ab62621. Primary BC cases (with signed informed consent) were used to generate tissue microarray platforms, where PR expression was accessed by IHC and evaluated by the Allred score.

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In the present study, we aimed to evaluate estrogen receptor ER-alpha status in 61 breast cancer cases using Sp1 and 1D5 monoclonal antibodies. Tissue array platforms were generated containing samples of breast cancer and positive controls that were assayed by immunohistochemistry applying monoclonal primary antibodies anti-ER alpha, SP1 and 1D5. We noted a high concordance rate (96.

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Objective: To evaluate the association of -397T>C and -351A>G single nucleotide polymorphisms (SNPs) - also called PvuII and XbaI, respectively - located on estrogen receptor alpha (ERS1) gene with age at menarche, menopause onset, fertility and miscarriage in a population of post-menopausal women.

Study Design: Cross-sectional study with 273 healthy, high miscegenated, post-menopausal women (mean age of 63.1±9.

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Advances in our understanding of CD4(+)CD25(+)Foxp3(+) regulatory T cells (T(Regs)) enabled the characterization of their activities in maintaining peripheral tolerance, preventing autoimmune diseases, and limiting chronic inflammatory diseases. Ironically, an effective action of these cells during tumor development can limit beneficial responses by suppressing immunity and limiting antitumor resistance, whereas one of the main functions of the immune system is to eliminate malignant cells. During the last years, the immunological role, mechanism of action, and clinical importance of these cells were profoundly characterized and the relationship between this subset of lymphocytes and cancerous cells arises as a key factor that influences tumor development.

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Introduction: The aim was to evaluate the ability of egg yolk antibody (IgY) in blocking Staphylococcus aureus growth in vitro.

Materials And Methods: Specific IgY was produced by immunizing hens with formalin-killed S. aureus (ATCC 33593).

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Tumor formation in immunocompetent hosts is believed to be dependent on the ability of tumor cells to evade the immune system, as suggested by the alterations of expression of the major histocompatibility complex (MHC) and related molecules in a number of cancers. Our previous serial analysis of gene expression (SAGE) study revealed that HLA-DRA (encoding the alpha chain of HLA-DR) is one of the most highly overexpressed genes in ovarian cancer. This finding was unanticipated, as overexpression of MHC molecules would be expected to increase tumor immunogenicity, therefore compromising tumor growth.

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