Association between VDR Gene Polymorphisms and Melanoma Susceptibility in a Colombian Population.

BACKGROUND: The vitamin D receptor (VDR) is responsible for mediating the effects of vitamin D through regulation of other gene transcriptions. There are several polymorphisms that alter the gene expression or the function of this protein. We aimed to analyze the association between two SNPs  of VDR gene and melanoma cancer in Colombian patients. METHODS: We included 120 healthy individual as controls and 120 melanoma cancer patients as cases . Patients in both groups were matched in terms of gender and age. The genotyping of rs731236 and rs2228570 polymorphisms was performed using PCR-RFLP. The SNPStats program was used to carry out the statistical analysis through a logistic regression model. RESULTS: Under dominant model, we found that rs2228570 polymorphism was associated with melanoma cancer risk (C/C vs C/T-T/T, OR: 5.10, 95% CI: 2.85-9.14), whereas rs731236 polymorphism was associated with a protective effect against this cancer (T/T vs T/C, OR: 0.27, 95% CI: 0.14-0.53). CONCLUSION: Our results suggested that both polymorphisms were involved in the development of melanoma cancer, increasing or decreasing this risk.

An Overview of C19MC Cluster Subgroup 3 and Cancer.

The primate-specific microRNA gene cluster on chromosome 19 (C19MC) is composed of 56 mature microRNAs (miRNAs), which are divided into three subgroups according to the sequence similarity. This cluster is principally expressed in the placenta but not in other tissues. C19MC is involved in the regulation of proliferation, migration, and invasion of trophoblastic cells, which are important for the development of the placenta. There is a growing number of studies that have found an altered expression of some miRNAs of the C19MC cluster in cancer, suggesting that these could play an important role in the development of this disease. Therefore, in this work, we provided an overview of the C19MC cluster's role in cancer through a systematic review of published articles. In particular, we focused on miRNAs of subgroup 3. These studies suggest that miRNAs such as miR-512-3p, miR-512-5p, miR-516a-5p, miR-516b-5p, and miR-498-5p could play a pivotal role in the development of therapies for cancer. Future studies are necessary to elucidate the molecular processes and pathways regulated by subgroup 3 miRNAs.

AR/ER Ratio Correlates with Expression of Proliferation Markers and with Distinct Subset of Breast Tumors.

The co-expression of androgen (AR) and estrogen (ER) receptors, in terms of higher AR/ER ratio, has been recently associated with poor outcome in ER-positive (ER+) breast cancer (BC) patients. The aim of this study was to analyze if the biological aggressiveness, underlined in ER+ BC tumors with higher AR/ER ratio, could be due to higher expression of genes related to cell proliferation. On a cohort of 47 ER+ BC patients, the AR/ER ratio was assessed by immunohistochemistry and by mRNA analysis. The expression level of five gene proliferation markers was defined through TaqMan®-qPCR assays. Results were validated using 979 BC cases obtained from gene expression public databases. ER+ BC tumors with ratios of AR/ER ≥ 2 have higher expression levels of cellular proliferation genes than tumors with ratios of AR/ER < 2, in both the 47 ER+ BC patients (P < 0.001) and in the validation cohort (P = 0.005). Moreover, BC cases with ratios of AR/ER ≥ 2 of the validation cohort were mainly assigned to luminal B and HER2-enriched molecular subtypes, typically characterized by higher proliferation and poorer prognosis. These data suggest that joint routine evaluation of AR and ER expression may identify a unique subset of tumors, which show higher levels of cellular proliferation and therefore a more aggressive behavior.

Genotoxic evaluation of occupational exposure to antineoplastic drugs.

During the last years, several reports have provided evidence about adverse health effects on personal involved in Antineoplastic Drugs (ANPD) handling. ANPD has the ability to bind DNA, thus produce genotoxic damage. In this way, XRCC1 and XRCC3 proteins are necessary for efficient DNA repair and polymorphisms in this genes can be associated with an individual response to ANPD exposure. Therefore, the aim of this study was to evaluate genetic damage of occupational exposure to antineoplastic drugs and the possible effect of XRCC1 and XRCC3 polymorphisms in oncology employees from Bogotá, Colombia. Peripheral blood samples were obtained from 80 individuals, among exposed workers and healthy controls. The comet assay and Cytokinesis-block micronucleus cytome assay was performed to determinate genetic damage. From every sample DNA was isolated and genotyping for XRCC1 (Arg194Trp, Arg280His and Arg399Gln) and XRCC3 (Thr241Met) SNPs by PCR-RFLP. The exposed group showed a significant increase of comet assay results and micronucleus frequency, compared with unexposed group. It was observed a gender, exposure time and workplace effect on comet assay results. Our results showed no significant associations of comet assay results and micronucleus frequency with either genotype, allele, nor haplotype of XRCC1 and XRCC3 SNPs. The results suggest that occupational exposure to ANPD may lead to genotoxic damage and even be a risk to human health. To our knowledge, this is the first study to assess the genotoxic damage of occupational exposure to APND in South America.

Glyphosate-based herbicides at low doses affect canonical pathways in estrogen positive and negative breast cancer cell lines.

Glyphosate is a broad-spectrum herbicide that is used worldwide. It represents a potential harm to surface water, and when commercially mixed with surfactants, its uptake is greatly magnified. The most well-known glyphosate-based product is Roundup. This herbicide is potentially an endocrine disruptor and many studies have shown the cytotoxicity potential of glyphosate-based herbicides. In breast cancer (BC) cell lines it has been demonstrated that glyphosate can induce cellular proliferation via estrogen receptors. Therefore, we aimed to identify gene expression changes in ER+ and ER- BC cell lines treated with Roundup and AMPA, to address changes in canonical pathways that would be related or not with the ER pathway, which we believe could interfere with cell proliferation. Using the Human Transcriptome Arrays 2.0, we identified gene expression changes in MCF-7 and MDA-MB-468 exposed to low concentrations and short exposure time to Roundup Original and AMPA. The results showed that at low concentration (0.05% Roundup) and short exposure (48h), both cell lines suffered deregulation of 11 canonical pathways, the most important being cell cycle and DNA damage repair pathways. Enrichment analysis showed similar results, except that MDA-MB-468 altered mainly metabolic processes. In contrast, 48h 10mM AMPA showed fewer differentially expressed genes, but also mainly related with metabolic processes. Our findings suggest that Roundup affects survival due to cell cycle deregulation and metabolism changes that may alter mitochondrial oxygen consumption, increase ROS levels, induce hypoxia, damage DNA repair, cause mutation accumulation and ultimately cell death. To our knowledge, this is the first study to analyze the effects of Roundup and AMPA on gene expression in triple negative BC cells. Therefore, we conclude that both compounds can cause cellular damage at low doses in a relatively short period of time in these two models, mainly affecting cell cycle and DNA repair.

Therapeutic Potential of Melatonin in the Regulation of MiR-148a-3p and Angiogenic Factors in Breast Cancer.

BACKGROUND: The high mortality rate of breast cancer is related to the occurrence of metastasis, a process that is promoted by tumor angiogenesis. MicroRNAs are small molecules of noncoding mRNA that play a key role in gene regulation and are directly involved in the progression and angiogenesis of various tumor types, including breast cancer. Several miRNAs have been described as promoters or suppressors angiogenesis and may be associated with tumor growth and metastasis. Melatonin is an oncostatic agent with a capacity of modifying the expression of innumerable genes and miRNAs related to cancer. OBJECTIVE: The aim of this study was to evaluate the role of melatonin and the tumor suppressor miR- 148a-3p on angiogenesis of breast cancer. METHOD: MDA-MB-231 cells were treated with melatonin and modified with the overexpression of miR-148a-3p. The relative quantification in real-time of miR-148a-3p, IGF-IR and VEGF was performed by real-time PCR. The protein expression of these targets was performed by immunocytochemistry and immunohistochemistry. Survival, migration and invasion rates of tumor cells were evaluated. Finally, the xenograft model of breast cancer was performed to confirm the role of melatonin in the tumor. RESULTS: The melatonin was able to increase the gene level of miR-148a-3p and decreased the gene and protein expression of IGF-1R and VEGF, both in vitro and in vivo. In addition, it also had an inhibitory effect on the survival, migration and invasion of breast tumor cells. CONCLUSION: Our results confirm the role of melatonin in the regulation of miR-148a-3p and decrease of angiogenic factors.

Caliphruria subedentata (Amaryllidaceae) decreases genotoxicity and cell death induced by ß-amyloid peptide in SH-SY5Y cell line.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by neuritic plaques (NPs), and neurofibrillary tangles (NFTs). ß-Amyloid peptide 1-4 2 (Aß(1-42)) is the principal component of NPs and is associated with oxidative stress, as well as dysfunction of cholinergic neurotransmission system and cell death. Nevertheless, one of the most promising therapeutic approaches for patients with AD is based on the pharmacological intervention to increases acetylcholine levels and reduces oxidative stress in AD brain. Previous studies have indicated that alkaloids from Amaryllidaceae family exhibit a wide range of biological activities. The purpose of this study was to investigate whether C. subedentata extract may modulate Aß(1-42)- induced genotoxicity in SH-SY5Y cell line. Here, we conducted a set of bioassays to measure: viability, clonogenic survival, cell death, chromosome damage and DNA strand breaks. The results showed that Aß(1-42) significantly inhibited cell viability through necrosis rather than apoptosis, increased the percentage of DNA damage and caused mitochondrial morphological alterations. Treatment with the C. subedentata extract led to a significant recovery of cell survival, decreased necrotic cell death and exerted an induction of antigenotoxic effects; additionally, the extract caigused inhibition of acetylcholinesterase (AChE). The present study confirms neuroprotective activities of C. subedentata belonging Amaryllidaceae family and provide a novel information to clarify the mechanisms by which the extracts decrease DNA damage levels induced by Aß(1-42).

Role of GSK3ß in breast cancer susceptibility.

BACKGROUND: Breast cancer is one of the principal causes of death among Brazilian women, so it is a challenge to find new and specific early diagnostic markers, using simple and fast procedures. GSK3ß gene is an important Wnt signaling regulator involved in ß-Catenin degradation. Wnt signaling is associated with initiation and progression process in many tumor types, and alterations in ß-Catenin explain only a small proportion of aberrant signaling found in breast cancer, indicating that other Wnt signaling components and/or regulators as GSK3ß may be involved. OBJECTIVE: The aim of this study was to evaluate the genetic, epigenetic and transcriptional alterations of GSK3ß in breast cancer. METHODS: Peripheral blood samples from 204 breast cancer and healthy women were collected. Assessment of rs334558 polymorphism was performed by PCR-RFLP, promoter methylation profiles analysis by MS-PCR and qPCR was used to determine GSK3ß expression levels. RESULTS: The rs334558 polymorphism showed a strong association with aggressive cancer. A significant increase was observed in GSK3ß expression level respect to hormone receptors status and tumor size. CONCLUSION: The results indicated an inverse relationship between GSK3ß performance and tumor progression. This is the first study to relate GSK3ß gene with breast cancer in Brazilian population.

[Effect of genetics, epigenetics and variations in the transcriptional expression of cadherin-E in breast cancer susceptibility].

INTRODUCTION: Cadherin-E (CDH1) is an important regulator of epithelial-mesenchymal transition, invasion and metastasis in many carcinomas. However, germinal epimutations and mutations effect in breast cancer susceptibility is not clear. OBJECTIVE: To evaluate rs334558 polymorphism, promoter methylation status and CDH1 expression profile in breast cancer patients. MATERIALS AND METHODS: We collected peripheral blood samples from 102 breast cancer patients and 102 healthy subjects. The identification of rs334558 polymorphism was performed using PCR-RFLP, while methylation-specific PCR (MSP) and methylation-sensitive high-resolution melting (MS-HRM) were used to explore CDH1 methylation status; finally, CDH1 transcriptional expression profile was evaluated using RT-qPCR. RESULTS: We found no association between rs334558 polymorphism and breast cancer. Aberrant promoter methylation profile was found in breast cancer patients and it was related with early cancer stages. CDH1 down-regulation was significantly associated with metastasis and promoter methylation. CONCLUSION: CDH1 alterations were associated with invasion and metastasis in breast cancer. Our results offer further evidence of CDH1 relevance in breast cancer development and progression.

Detection of human mammaglobin A mRNA in peripheral blood of breast cancer patients before treatment and association with metastasis.

BACKGROUND: Mammaglobin A (MGA), mainly expressed in the breast epithelium, is overexpressed in breast cancer, and has been established as a tumor and promissory marker for the early detection of metastasis. AIM: The main aim of this study was to evaluate the association between the presence of the MGA transcript in the peripheral blood of Brazilian breast cancer patients and healthy women and the development of breast cancer and tumor progression. MATERIAL AND METHODS: The expression of the MGA transcript in peripheral blood of 102 breast cancer patients and 102 healthy women was assessed by RT-PCR. RESULTS: MGA mRNA was expressed in the peripheral blood of 39 breast cancer patients and in none of the women from the control group. The presence of MGA was significantly associated with presence of metastasis and age at onset after 60 years. The presence of MGA mRNA in peripheral blood displayed a sensitivity of 38.2%, specificity of 100.0%, positive predictive value (PPV) of 100.0%, and negative predictive value (NPV) of 61.8% as a breast cancer marker. CONCLUSION: This study provides additional evidence of the presence of MGA in the peripheral blood of breast cancer patients, and its applicability as an efficient biomarker for breast cancer (High specificity and PPV). To our knowledge, this is the first study to assess the expression of MGA mRNA in peripheral blood obtained from the Brazilian population.

AXIN2 Polymorphisms, the ß-Catenin Destruction Complex Expression Profile and Breast Cancer Susceptibility.

BACKGROUND: The Wnt/ß-catenin signaling pathway is an important regulator of cellular functions such as proliferation, survival and cell adhesion. Wnt/ß-catenin signaling is associated with tumor initiation and progression; ß-catenin mutations explain only 30% of aberrant signaling found in breast cancer, indicating that other components and/or regulation of the Wnt/ß-catenin pathway may be involved. OBJECTIVE: We evaluated AXIN2 rs2240308 and rs151279728 polymorphisms, and expression profiles of ß-catenin destruction complex genes in breast cancer patients. MATERIALS AND METHODS: We collected peripheral blood samples from 102 breast cancer and 102 healthy subjects. The identification of the genetic variation was performed using PCR-RFLPs and DNA sequencing. RT-qPCR was used to determine expression profiles. RESULTS: We found significant association of AXIN2 rs151279728 and rs2240308 polymorphisms with breast cancer risk. Significant increase was observed in AXIN2 level expression in breast cancer patients. Further analyses showed APC, ß-catenin, CK1α, GSK3ß and PP2A gene expression to be associated to clinic-pathological characteristics. CONCLUSIONS: The present study demonstrated, for the first time, that AXIN2 genetic defects and disturbance of ß-catenin destruction complex expression may be found in breast cancer patients, providing additional support for roles of Wnt/ß-catenin pathway dysfunction in breast cancer tumorigenesis. However, the functional consequences of the genetic alterations remain to be determined.