CCR5 and CXCL12 allelic variants: Possible association with childhood neuroblastoma susceptibility?

Neuroblastoma (NB) is a heterogeneous and particularly malignant childhood neoplasm in its higher stages, prone to form metastasis in selected organs and for which there is still no efficient treatment available beyond surgery. Evidence indicates that chemokines and their receptors present involvement as mediators of neuroinflammation and have a neurophysiological role. In the present study, we aimed to verify if CCR5 (rs333) and CXCL12 (rs1801157) allelic variants were associated with NB. For CCR5 (rs333) D32 carriers (OR: 5.96, IC: 2.21-16.06) and for CXCL12 genotype 3'A/3'A (OR:26.18, IC:6.15-111.4) there were statistically significant differences as well to allelic frequency (OR:4.20, IC: 2.19-8.03). Although no correlation was verified regarding prognostic parameters for both CCR5 and CXCL12 polymorphic variants, these polymorphisms may be associated with NB susceptibility which deserve attention for future investigations.

Mutation in NADPH oxidase 3 (NOX3) impairs SHH signaling and increases cerebellar neural stem/progenitor cell proliferation

Abnormalities in cerebellar structure and function may cause ataxia, a neurological dysfunction of motor coordination. In the course of the present study, we characterized a mutant mouse lineage with an ataxia-like phenotype. We localized the mutation on chromosome 17 and mapped it to position 1534 of the Nox3 gene, resulting in p.Asn64Tyr change. The primary defect observed in Nox3^eqlb mice was increased proliferation of cerebellar granule cell precursors (GCPs). cDNA microarray comparing Nox3^eqlb and BALB/c neonatal cerebellum revealed changes in the expression of genes involved in the control of cell proliferation. Nox3^eqlb GCPs and NSC produce higher amounts of reactive oxygen species (ROS) and upregulate the expression of SHH target genes, such as Gli1-3 and Ccnd1 (CyclinD1). We hypothesize that this new mutation is responsible for an increase in proliferation via stimulation of the SHH pathway. We suggest this mutant mouse lineage as a new model to investigate the role of ROS in neuronal precursor cell proliferation.

HER2 Ile655Val polymorphism is negatively associated with breast cancer susceptibility

BACKGROUND

The HER2 (human epidermal growth factor receptor-2) Ile655Val (rs1136201) genetic polymorphism can alter the receptor structure and its auto-activation, which can modify the signal transduction and, consequently, the cell cycle regulation. For this reason, this polymorphism has been extensively investigated as a candidate marker for breast cancer (BC). In this context, the aim of this study was to evaluate the possible influence of HER2 Ile655Val in BC susceptibility and prognostic factors in a Brazilian population.

METHODS

Polymorphism genotype was assessed through RFLP-PCR in 107 BC patients with clinicopathological data available and in 150 women with no evidence of neoplasia and with no familial history of BC as control group. Association between this polymorphism and BC susceptibility and clinical parameters was evaluated through odds ratio (OR) and chi-squared or Fisher's exact test, respectively.

RESULTS

A significant negative association between valine allele and BC susceptibility in dominant model was found (OR 0.5; 95% CI 0.27-0.93, P = .036). No significant association was found in relation to BC clinicopathological features (tumor size, lymph nodes commitment, histological grade, HER2 overexpression, hormonal receptors, p53, and Ki-67).

CONCLUSION

Although this polymorphism did not demonstrate potential as a prognostic marker, it may be a suitable susceptibility marker for BC.

The predictive value of transforming growth factor-β in Wilms tumor immunopathogenesis

Wilms tumor is the most common kidney malignancy in children, especially in children aged less than 6 years. Although therapeutic approach has reached successful rates, there is still room for improvement. Considering the tumor microenvironment, cytokines represent important elements of interaction and communication between tumor cells, stroma, and immune cells. In this regard, the transforming growth factor beta (TGF-β) family members play significant functions in physiological and pathological conditions, particularly in cancer. By regulating cell growth, death, and immortalization, TGF-β signaling pathways exert tumor suppressor effects in normal and early tumor cells. Thus, it is not surprising that a high number of human tumors arise due to alterations in genes coding for various TGF-β signaling components. Understanding the ambiguous role of TGF-β in human cancer is of paramount importance for the development of new therapeutic strategies to specifically block the metastatic signaling pathway of TGF-β without affecting its tumor suppressive effect. In this context, this review attempt to summarize the involvement of TGF-β in Wilms tumor.

Wilms' tumor susceptibility: possible involvement of FOXP3 and CXCL12 genes

Background

Wilms’ tumor is an embryonal neoplasm of the kidney that accounts for approximately 6 % of all childhood tumors. The chemokine CXCL12 (C-X-C chemokine ligand 12) and its ligand CXCR4 (C-X-C chemokine receptor type 4) are involved in the development of several organs, including the kidney, and are also associated with tumor growth and metastasis. FOXP3 (forkhead transcription factor 3) was initially described as a marker for regulatory T cells; however, its expression in several types of tumor cells has already been described and may have prognostic significance. The aim of the present study was to analyze rs3761548 and rs2232365 FOXP3 polymorphisms, as well as evaluate rs1801157 CXCL12 polymorphism in Wilms’ tumor samples.

Methods

Polymorphisms were evaluated in 32 patients and 78 neoplasia-free controls. Genotypes of rs1801157 were determined using PCR-restriction fragment length polymorphism (PCR-RFLP) method, and genotypes of rs2232365 and rs3761548 were determined using allele-specific PCR (AS-PCR).

Results

The case-control study indicated a significant association for allele A carriers of rs1801157 polymorphism in relation to Wilms’ tumor susceptibility (OR = 5.261; 95 % CI 2.156 to 12.84; p = 0.0002). The opposite was observed in male carriers of G allele for rs2232365 polymorphism (OR 0.1164; 95 % CI 0.0227 to 0.5954; p = 0.0091) or when male and female subjects were analyzed (OR = 0.1304; 95 % CI 0.05013 to 0.3394; p < 0.0001).

Conclusions

All in all, these markers may contribute to this neoplasia susceptibility and progression; however, further studies are needed to real clarify their role in Wilms’ tumor pathogenesis.

Genetic Polymorphism in the Promoter Region of Serotonin Transporter: Implications for Ethanol Abuse in Children and Adolescents

OBJECTIVES

To provide a review of published literature regarding genetic polymorphism of serotonin transporter gene, named as 5-HTTLPR, and its potential role as a susceptibility marker for ethanol abuse in childhood and adolescence.

METHODS

A literature review of several databases was conducted with the following keywords: 5-HTTLPR, children or adolescents or teenagers, susceptibility, alcohol or ethanol, abuse or misuse.

RESULTS

Alcohol interacts with serotonergic synaptic transmission in several ways, and the reduced availability of serotonin transporters might foster brain dysfunction, driving to alcohol abuse. The initial use of ethanol in children and adolescents is determined primarily by environmental influences, whereas the establishment of drinking patterns is strongly controlled by genetic factors. Functional polymorphic variants in the promoter region of the 5-HTTLPR gene have age-dependent effects in alcohol abuse. This polymorphism, mapped to the 5' region of the SLC6A4, is a variable number of tandem repeats (VNTR) and involves a direct repeat of 20-23 base pairs GC-rich sequences, comprising a short (S) allele, consisting of 14 repeats, and a long (L) allele, with 16 repeats. Additional variants have been described, although their influences on childhood and adolescence ethanol use are not clear.

CONCLUSION

The influence of the 5-HTTLPR allelic variants in children and adolescent misuse of alcohol might be considered for clinical management, preventing long-term behavior problem. Identifying genetic markers associated to the potential alcohol misuse or abuse could be useful in guiding management and formulating effective coping strategies.

STin2 VNTR polymorphism is associated with comorbid tobacco use and mood disorders

BACKGROUND

There is a significant comorbidity between mood disorders and tobacco use disorder (TUD), which may be related to both genetic and environmental factors. Gene variants of the 5-HT transporter, such as STin2 VNTR (a variable number of tandem repeats in the functional serotonin transporter intron 2) may be associated with mood disorders and TUD.

AIMS

This study aimed to delineate the association between the STin2 genetic polymorphism and comorbid TUD and mood disorders, including depression or bipolar disorder.

METHODS

We examined the STin2 VNTR polymorphism in never-smokers (n=113); patients with mood disorders without TUD (n=62); patients with TUD without mood disorders (n=90); and patients with both disorders (n=95).

RESULTS

We found a significant association between the STin2 genetic polymorphism and the above diagnostic groups whereby the STin2.12 allele shows a positive association with comorbid TUD and mood disorders (Odds ratio=3.07, 95% CI=1.41-6.68), while the STin2.10/10 homozygous genotype shows a negative association (Odds ratio=0.34, 95% CI=0.16-0.74). Adjusting for years of education, age, gender, marital status and ethnicity did not change these results, but showed that TUD was associated with lower education levels and less stable relationships, whereas mood disorders were related to female gender. A family history of TUD was significantly associated with TUD in subjects without mood disorders only.

CONCLUSIONS

The STin2.12 allele is positively and the STin2.10/10 genotype is negatively associated with comorbid TUD and mood disorders, depression or bipolar depression, suggesting that biological endophenotypes, e.g. disorders in serotonin metabolism, may in part underpin this comorbidity.

Role of CXCL12 and CXCR4 in normal cerebellar development and medulloblastoma

Chemokines and its receptors have significant impact on physiological and pathological processes and studies concerning their association with tumor biology are subject of great interest in scientific community. CXCL12/CXCR4 axis has been widely studied due to its significant role in tumor microenvironment, but it is also important to development and maintenance of tissues and organs, for example, in the brain and cerebellum. Studies have demonstrated that CXCL12 and CXCR4 are required for normal cerebellar development and that dysfunction in this pathway may be involved with medulloblastoma pathogenesis. In this context, a new molecular subgroup has been suggested based on the importance of the association between CXCR4 overexpression and sonic hedgehog subgroup. Treatment using CXCR4 antagonists showed significant results, evidencing the important role and possible therapeutic capacity of CXCR4 in MB. This review summarizes studies on MB cell biology, focusing on a chemokine-receptor axis, CXCL12/CXCR4, that may have implications for treatment strategies once it can improve life expectancy and reduce neurocognitive sequelae of patients with this neoplasia.

SLC6A4 STin2 VNTR genetic polymorphism is associated with tobacco use disorder, but not with successful smoking cessation or smoking characteristics: a case control study

Background

The aim of this study was to determine if variable number of tandem repeats (VNTR) in the second intron (STin2) of the serotonin transporter (SLC6A4) gene was associated with tobacco use disorder, successful smoking cessation, or smoking characteristics. In this case–control study, patients with current tobacco use disorder, diagnosed according to DSM IV criteria (n = 185), and never-smokers, diagnosed according to CDC criteria (n = 175), were recruited and received 52 weeks of combined pharmacotherapy and cognitive therapy. Successful smoking cessation was defined as exhaled carbon monoxide < 6 ppm. SLC6A4 gene STin2 VNTR polymorphism was assessed using a Multiplex-PCR-based method. At baseline, participants were evaluated using the Fagerström Test for Nicotine Dependence (FTND) and the ASSIST scale.

Results

The STin2.12 allele (OR = 2.45; 95% CI = 1.44-4.15, p < 0.001) was associated with an increased risk for tobacco use disorder, while the STin2.10/10 genotype (OR = 0.42; 95% CI 0.25-0.71, p < 0.001) decreased risk. There were no significant associations between tobacco use disorder and the STin2.10 or STin2.9 alleles or the other genotypes (STin2.12/12, 12/10, 12/9, 10/9 or 9/9). There were no significant associations between the STin2 genotypes and alleles and successful smoking cessation, smoking characteristics and increased alcohol or sedative use risk.

Conclusions

Our results suggest that the STin2.10/10 genotype and STin2.12 allele are associated with tobacco use disorder or nicotine dependence, but not with treatment response or severity of dependence. It is hypothesized that the ST2in.12 allele by modulating the metabolism of serotonin may participate in the pathophysiology of tobacco use disorder or nicotine dependence.

Molecular markers for breast cancer: prediction on tumor behavior

Breast cancer is one of the most common cancers with greater than 1,300,000 cases and 450,000 deaths each year worldwide. The development of breast cancer involves a progression through intermediate stages until the invasive carcinoma and finally into metastatic disease. Given the variability in clinical progression, the identification of markers that could predict the tumor behavior is particularly important in breast cancer. The determination of tumor markers is a useful tool for clinical management in cancer patients, assisting in diagnostic, staging, evaluation of therapeutic response, detection of recurrence and metastasis, and development of new treatment modalities. In this context, this review aims to discuss the main tumor markers in breast carcinogenesis. The most well-established breast molecular markers with prognostic and/or therapeutic value like hormone receptors, HER-2 oncogene, Ki-67, and p53 proteins, and the genes for hereditary breast cancer will be presented. Furthermore, this review shows the new molecular targets in breast cancer: CXCR4, caveolin, miRNA, and FOXP3, as promising candidates for future development of effective and targeted therapies, also with lower toxicity.

Inducing mutations in the mouse genome with the chemical mutagen ethylnitrosourea

When compared to other model organisms whose genome is sequenced, the number of mutations identified in the mouse appears extremely reduced and this situation seriously hampers our understanding of mammalian gene function(s). Another important consequence of this shortage is that a majority of human genetic diseases still await an animal model. To improve the situation, two strategies are currently used: the first makes use of embryonic stem cells, in which one can induce knockout mutations almost at will; the second consists of a genome-wide random chemical mutagenesis, followed by screening for mutant phenotypes and subsequent identification of the genetic alteration(s). Several projects are now in progress making use of one or the other of these strategies. Here, we report an original effort where we mutagenized BALB/c males, with the mutagen ethylnitrosourea. Offspring of these males were screened for dominant mutations and a three-generation breeding protocol was set to recover recessive mutations. Eleven mutations were identified (one dominant and ten recessives). Three of these mutations are new alleles (Otop1mlh, Foxn1sepe and probably rodador) at loci where mutations have already been reported, while 4 are new and original alleles (carc, eqlb, frqz, and Sacc). This result indicates that the mouse genome, as expected, is far from being saturated with mutations. More mutations would certainly be discovered using more sophisticated phenotyping protocols. Seven of the 11 new mutant alleles induced in our experiment have been localized on the genetic map as a first step towards positional cloning.