Metformin is a widely used antidiabetic drug whose anticancer effects, mediated by the activation of AMP-activated protein kinase (AMPK) and reduction of mTOR signaling, have become noteworthy. ...Chemotherapy produces genotoxic stress and induces p53 activity, which can cross-talk with AMPK/mTOR pathway. Herein, we investigate whether the combination of metformin and paclitaxel has an effect in cancer cell lines.
Human tumors were xenografted into severe combined immunodeficient (SCID) mice and the cancer cell lines were treated with only paclitaxel or only metformin, or a combination of both drugs. Western blotting, flow cytometry, and immunohistochemistry were then used to characterize the effects of the different treatments.
The results presented herein show that the addition of metformin to paclitaxel leads to quantitative potentialization of molecular signaling through AMPK and a subsequent potent inhibition of the mTOR signaling pathway. Treatment with metformin and paclitaxel resulted in an increase in the number of cells arrested in the G(2)-M phase of the cell cycle, and decreased the tumor growth and increased apoptosis in tumor-bearing mice, when compared with individual drug treatments.
We have provided evidence for a convergence of metformin and paclitaxel induced signaling at the level of AMPK. This mechanism shows how different drugs may cooperate to augment antigrowth signals, and suggests that target activation of AMPK by metformin may be a compelling ally in cancer treatment.
Overcoming challenges for the unambiguous detection of copy number variations is essential to broaden our understanding of the role of genomic variants in the clinical phenotype. With the improvement ...of software and databases, whole-exome sequencing quickly can become an excellent strategy in the routine diagnosis of patients with a developmental delay and/or multiple congenital malformations. However, even after a detailed analysis of pathogenic single-nucleotide variants and indels in known disease genes, using whole-exome sequencing, some patients with suspected syndromic conditions are left without a conclusive diagnosis. These negative results could be the result of different factors including nongenetic etiologies, lack of knowledge about the genes that cause different disease phenotypes, or, in some cases, a deletion or duplication of genomic information not routinely detectable by whole-exome sequencing variant calling. Although copy number variant detection is possible using whole-exome sequencing data, such analysis presents significant challenges and cannot yet be used to replace chromosomal arrays for identification of deletions or duplications.
Introduction: Cri-du-chat syndrome is generally diagnosed when patients present a high-pitched cry at birth, microcephaly, ocular hypertelorism, and prominent nasal bridge. The karyotype is useful to ...confirm deletions in the short arm of chromosome 5 (5p–) greater than 10 Mb. In cases of smaller deletions, it is necessary to resort to other molecular techniques such as fluorescence in situ hybridization, multiplex ligation-dependent probe amplification (MLPA) or genomic array. Case Presentation: We report a family with an atypical deletion in 5p (mother and 2 children) and variable phenotypes compared with the literature. We applied a P064 MLPA kit to evaluate 5p– in the mother and the 2 children, and we used the Infinium CytoSNP-850K BeadChip genomic array to evaluate the siblings, an 11-year-old boy and a 13-year-old girl, to better define the 5p breakpoints. Both children presented a high-pitched cry at birth, but they did not present any of the typical physical features of 5p– syndrome. The MLPA technique with 5 probes for the 5p region revealed that the patients and their mother presented an atypical deletion with only 4 probes deleted (TERT_ex2, TERT_ex13, CLPTM1L, and IRX4). The genomic array performed in the siblings’ samples revealed a 6.2-Mb terminal deletion in 5p15.33p15.32, which was likely inherited from their mother, who presented similar molecular features, seen in MLPA. Discussion: The sparing of the CTNND2 gene, which is associated with cerebral development, in both siblings may explain why these 2 patients had features such as better communication skills which most patients with larger 5p deletions usually do not present. In addition, both patients had smaller deletions than those found in patients with a typical 5p– phenotype. This report demonstrates the utility of genomic arrays as a diagnostic tool to better characterize atypical deletions in known syndromes such as 5p– syndrome, which will allow a better understanding of the genotype-phenotype correlations.
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).
This article has been retracted at the request of the ...Editor-in-Chief and Deputy Editor-in-Chief following an investigation into the data that were presented in several figures within the article.
A number of images used in this article are believed to be duplicated images. The authors stated that they inadvertently inserted images of the wrong blots in several of the figures, resulting in the duplications; however, they did not address all of the concerns raised. Because the editors were no longer confident in the conclusions of the article based on these incorrect data, a decision was made to retract the paper.
All authors have been notified of this decision. The University of Campinas (UNICAMP) in São Paulo, Brazil was contacted regarding these concerns, but to date the journal has received no response.
Consuming a low-iodine diet (LID) is a widely accepted practice before administering radioiodine (131I) to evaluate and to treat thyroid disease. Although this procedure is well established for the ...management of patients with differentiated thyroid cancer, its use in patients with benign disease is unclear. So, we aimed to evaluate the influence of a LID on the outcome in patients with Graves' disease (GD) treated with 131I.
We evaluated 67 patients with GD who were divided into 2 groups: one group (n = 31) consumed a LID for 1-2 weeks, and the second group (n = 36) was instructed to maintain a regular diet (RD).
The LID group experienced a 23% decrease in urinary iodine after 1 week on the diet and a significant 42% decrease after 2 weeks on the diet. The majority (53%) of the patients in the LID group had urinary iodine levels that were consistent with deficient iodine intake. However, there was no difference in the rate of hyperthyroidism's cure between the LID and the RD groups 6 months after 131I therapy. Furthermore, the therapeutic efficacy did not differ in patients with varying degrees of sufficient iodine intake (corresponding urinary iodine levels: < 10 μg/dL is deficient; 10-29.9 μg/dL is sufficient; and > 30 μg/dL is excessive).
In the present study, we demonstrated that although a LID decreased urinary iodine levels, those levels corresponding with sufficient or a mild excess in iodine intake did not compromise the therapeutic efficacy of 131I for the treatment of GD.
Background
Cri du chat syndrome (CdCS) is a rare syndrome caused by a partial or complete deletion of the short arm of chromosome 5 (5p‐). The main clinical features include a high‐pitched cry, ...facial asymmetry, microcephaly, round face at birth, epicanthal folds, hypotonia, delayed growth and development.
Methods
We studied 14 Brazilian patients with CdCS using genomic array in order to better define the 5p breakpoints and recognize copy number variations (CNVs) that contribute to clinical manifestations associated with the syndrome.
Results
Array confirmed terminal deletions in 13 patients and an interstitial deletion in one patient. It was also possible to map the breakpoints and associate a genomic region of 4.7 Mb to the development of head circumference and cat‐like cry. We also found other CNVs concomitant to the 5p deletion including a 9p duplication, a 17q deletion, and a 22q deletion in three different patients.
Conclusion
With advancements of molecular cytogenomic methods in the last two decades, it was possible to evidence cryptic alterations and improve the genotype–phenotype correlation. In this work, we describe a new genomic region associated with microcephaly and cat‐like cry and highlight the importance of precise delineation of 5p deletion breakpoints and detection of other CNVs in CdCS patients to improve genotype–phenotype correlation to perform a complete clinical and molecular diagnosis.
We studied 14 Brazilian patients with Cri du chat syndrome using arrays and suggest a new genomic region associated with microcephaly and cat‐like cry. Also we highlight the importance of precise delineation of 5p deletion breakpoints for better genotype–phenotype correlation.
Background & Aims Epidemiology studies have shown that obesity increases risk for colorectal cancer (CRC). We investigated the contribution of obesity-induced increases in levels of tumor necrosis ...factor (TNF)-α and hyperinsulinemia to the development of CRC in mice. Methods Lean and obese mice (C57BL6/J and ob/ob ) were given a combination of azoxymethane and dextran sulfate sodium, which led to the development of CRC; lean and obese severe combined immunodeficient mice were injected with HT-29 cells. We analyzed the roles of TNF-α and insulin in the development of obesity-mediated CRC using immunoblot, immunohistochemical, and apoptosis assays. Results Genetic- and diet-induced obesity increased the incidence and size of tumors that developed after administration of azoxymethane and dextran sulfate sodium, compared with lean mice. HT-29 xenograft tumors grew more rapidly in obese than lean mice. Neutralization of TNF-α reduced activation of c-Jun N-terminal kinase, IκB kinase, and the phosphatidylinositol 3-kinase–Akt–mammalian target of rapamycin signaling pathway; it also reduced the growth and development of tumors in obese mice. Reducing levels of insulin levels had no effect on tumor growth in obese mice. Conclusions TNF-α contributes to colon tumor growth in obese mice. Reagents that inhibit TNF-α might prevent the development or progression of CRC in obese individuals.
A high-protein diet (HPD) is known to promote the reduction of body fat, but the mechanisms underlying this change are unclear. AMP-activated protein kinase (AMPK) and mammalian target of rapamycin ...(mTOR) function as majors regulators of cellular metabolism that respond to changes in energy status, and recent data demonstrated that they also play a critical role in systemic energy balance. Here, we sought to determine whether the response of the AMPK and mTOR pathways could contribute to the molecular effects of an HPD.
Western blotting, confocal microscopy, chromatography, light microscopy, and RT-PCR assays were combined to explore the anorexigenic effects of an HPD.
An HPD reduced food intake and induced weight loss in both normal rats and ob/ob mice. The intracerebroventricular administration of leucine reduced food intake, and the magnitude of weight loss and reduction of food intake in a leucine-supplemented diet are similar to that achieved by HPD in normal rats and in ob/ob mice, suggesting that leucine is a major component of the effects of an HPD. Leucine and HPD decrease AMPK and increase mTOR activity in the hypothalamus, leading to inhibition of neuropeptide Y and stimulation of pro-opiomelanocortin expression. Consistent with a cross-regulation between AMPK and mTOR to control food intake, our data show that the activation of these enzymes occurs in the same specific neuronal subtypes.
These findings provide support for the hypothesis that AMPK and mTOR interact in the hypothalamus to regulate feeding during HPD in a leucine-dependent manner.
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