Healing Actions of Essential Oils from Citrus aurantium and d-Limonene in the Gastric Mucosa: The Roles of VEGF, PCNA, and COX-2 in Cell Proliferation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inorganic elemental analysis and identification of residual monomers released from different glass ionomer cements in cell culture medium

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sodium intake, brain c-Fos protein and gastric emptying in cell-dehydrated rats treated with methysergide into the lateral parabrachial nucleus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Expression of genes from the lignin synthesis pathway in guineagrass genotypes differing in cell-wall digestibility

Rapid decline in cell-wall digestibility hinders efficient use of warm-season grasses. The objective of this study was to identify genes whose expressions are related to the slope of decline in cell-wall digestibility. Eleven guineagrass genotypes were harvested at three ages and classified according to fibre digestibility. Extreme genotypes were separated into groups with either FAST or SLOW decline in fibre digestibility. Expression of transcripts from six genes from the lignin synthesis pathway was quantified by real-time PCR. Fast decline in fibre digestibility was associated with higher DM yield after 90 d of regrowth. Apart from lower fibre digestibility and higher lignin content for the FAST group, there were no other differences between the two groups for the chemical composition of stems and leaves. Maturity affected differently the expression of two of the six genes, cinnamate 4-hydroxylase and caffeoyl-CoA O-methyltransferase (C4H and CCoAOMT). Genotypes with fast decline in fibre digestibility had greater increase in the expression of C4H and CCoAOMT from 30 to 60 d of regrowth, than genotypes with slower decline. Expression of C4H and CCoAOMT appears to be related to the decline in cell-wall digestibility with advance in maturity of guineagrass.

Quantitative proteomic analysis and functional studies reveal that nucleophosmin is involved in cell death in glioblastoma cell line transfected with siRNA

Previously, we reported that nucleophosmin (NPM) was increased in glioblastoma multiforme (GBM). NPM is a phosphoprotein related to apoptosis, ribosome biogenesis, mitosis, and DNA repair, but details about its function remain unclear. We treated U87MG and A172 cells with small interference RNA (siRNA) and obtained a reduction of 80% in NPM1 expression. Knockdown at the protein level was evident after the 4th day and was maintained until the 7th day of transfection that was investigated by quantitative proteomic analysis using isobaric tags. The comparison of proteomic analysis of NPM1-siRNA against controls allowed the identification of 14 proteins, two proteins showed increase and 12 presented a reduction of expression levels. Gene ontology assigned most of the hypoexpressed proteins to apoptosis regulation, including GRP78. NPM1 silencing did not impair cell proliferation until the 7th day after transfection, but sensitized U87MG cells to temozolomide (TMZ), culminating with an increase in cell death and provoking at a later period a reduction of colony formation. In a large data set of GBM patients, both GRP78 and NPM1 genes were upregulated and presented a tendency to shorter overall survival time. In conclusion, NPM proved to participate in the apoptotic process, sensitizing TMZ-treated U87MG and A172 cells to cell death, and in association with upregulation of GRP78 may be helpful as a predictive factor of poor prognosis in GBM patients.

High-throughput sequencing of small RNA transcriptomes reveals critical biological features targeted by microRNAs in cell models used for squamous cell cancer research

Abstract Background The implication of post-transcriptional regulation by microRNAs in molecular mechanisms underlying cancer disease is well documented. However, their interference at the cellular level is not fully explored. Functional in vitro studies are fundamental for the comprehension of their role; nevertheless results are highly dependable on the adopted cellular model. Next generation small RNA transcriptomic sequencing data of a tumor cell line and keratinocytes derived from primary culture was generated in order to characterize the microRNA content of these systems, thus helping in their understanding. Both constitute cell models for functional studies of microRNAs in head and neck squamous cell carcinoma (HNSCC), a smoking-related cancer. Known microRNAs were quantified and analyzed in the context of gene regulation. New microRNAs were investigated using similarity and structural search, ab initio classification, and prediction of the location of mature microRNAs within would-be precursor sequences. Results were compared with small RNA transcriptomic sequences from HNSCC samples in order to access the applicability of these cell models for cancer phenotype comprehension and for novel molecule discovery. Results Ten miRNAs represented over 70% of the mature molecules present in each of the cell types. The most expressed molecules were miR-21, miR-24 and miR-205, Accordingly; miR-21 and miR-205 have been previously shown to play a role in epithelial cell biology. Although miR-21 has been implicated in cancer development, and evaluated as a biomarker in HNSCC progression, no significant expression differences were seen between cell types. We demonstrate that differentially expressed mature miRNAs target cell differentiation and apoptosis related biological processes, indicating that they might represent, with acceptable accuracy, the genetic context from which they derive. Most miRNAs identified in the cancer cell line and in keratinocytes were present in tumor samples and cancer-free samples, respectively, with miR-21, miR-24 and miR-205 still among the most prevalent molecules at all instances. Thirteen miRNA-like structures, containing reads identified by the deep sequencing, were predicted from putative miRNA precursor sequences. Strong evidences suggest that one of them could be a new miRNA. This molecule was mostly expressed in the tumor cell line and HNSCC samples indicating a possible biological function in cancer. Conclusions Critical biological features of cells must be fully understood before they can be chosen as models for functional studies. Expression levels of miRNAs relate to cell type and tissue context. This study provides insights on miRNA content of two cell models used for cancer research. Pathways commonly deregulated in HNSCC might be targeted by most expressed and also by differentially expressed miRNAs. Results indicate that the use of cell models for cancer research demands careful assessment of underlying molecular characteristics for proper data interpretation. Additionally, one new miRNA-like molecule with a potential role in cancer was identified in the cell lines and clinical samples.

MicroRNA expression profile in head and neck cancer: HOX-cluster embedded microRNA-196a and microRNA-10b dysregulation implicated in cell proliferation

Abstract Background Current evidence implicates aberrant microRNA expression patterns in human malignancies; measurement of microRNA expression may have diagnostic and prognostic applications. Roles for microRNAs in head and neck squamous cell carcinomas (HNSCC) are largely unknown. HNSCC, a smoking-related cancer, is one of the most common malignancies worldwide but reliable diagnostic and prognostic markers have not been discovered so far. Some studies have evaluated the potential use of microRNA as biomarkers with clinical application in HNSCC. Methods MicroRNA expression profile of oral squamous cell carcinoma samples was determined by means of DNA microarrays. We also performed gain-of-function assays for two differentially expressed microRNA using two squamous cell carcinoma cell lines and normal oral keratinocytes. The effect of the over-expression of these molecules was evaluated by means of global gene expression profiling and cell proliferation assessment. Results Altered microRNA expression was detected for a total of 72 microRNAs. Among these we found well studied molecules, such as the miR-17-92 cluster, comprising potent oncogenic microRNA, and miR-34, recently found to interact with p53. HOX-cluster embedded miR-196a/b and miR-10b were up- and down-regulated, respectively, in tumor samples. Since validated HOX gene targets for these microRNAs are not consistently deregulated in HNSCC, we performed gain-of-function experiments, in an attempt to outline their possible role. Our results suggest that both molecules interfere in cell proliferation through distinct processes, possibly targeting a small set of genes involved in cell cycle progression. Conclusions Functional data on miRNAs in HNSCC is still scarce. Our data corroborate current literature and brings new insights into the role of microRNAs in HNSCC. We also show that miR-196a and miR-10b, not previously associated with HNSCC, may play an oncogenic role in this disease through the deregulation of cell proliferation. The study of microRNA alterations in HNSCC is an essential step to the mechanistic understanding of tumor formation and could lead to the discovery of clinically relevant biomarkers.

Roles of Ecdysone signaling in cell survival and epithelium morphogenesis during Drosophila melanogaster development

In Drosophila the steroid hormone ecdysone regulates a wide range of developmental and physiological responses, including reproduction, embryogenesis, postembryonic development and metamorphosis. Drosophila provides an excellent system to address some fundamental questions linked to hormone actions. In fact, the apparent relative simplicity of its hormone signaling pathways taken together with well-established genetic and genomic tools developed to this purpose, defines this insect as an ideal model system for studying the molecular mechanisms through which steroid hormones act. During my PhD research program I’ve analyzed the role of ecdysone signaling to gain insight into the molecular mechanisms through which the hormone fulfills its pleiotropic functions in two different developmental stages: the oogenesis and the imaginal wing disc morphogenesis. To this purpose, I performed a reverse genetic analysis to silence the function of two different genes involved in ecdysone signaling pathway, EcR and ecd.

Autophagy: in: Cell Death

Autophagy is a conserved proteolytic mechanism that degrades cytoplasmic material including cell organelles. Although the importance of autophagy for cell homeostasis and survival has long been appreciated, our understanding of how autophagy is regulated at a molecular level just recently evolved. The importance of autophagy for the quality control of proteins is underscored by the fact that many neurodegenerative and myodegenerative diseases are characterized by an increased but still insufficient autophagic activity. Similarly, if the cellular stress, leading to deoxyribonucleic acid (DNA) damage, mitochondrial damage and/or damaged proteins, does not result in sufficient autophagic repair mechanisms, cells seem to be prone to transform into tumour cells. Therefore, autophagy has multiple roles to play in the causation and prevention of human diseases.

Changes in cell proliferation, but not in vascularisation are characteristic for human endometrium in different reproductive failures--a pilot study

Reproductive failure, determined as recurrent spontaneous abortions (RSA) or recurrent implantation failure (RIF) in women is not well understood. Several factors, including embryo quality, and cellular and molecular changes in endometrium may contribute to the insufficient feto-maternal interaction resulting in reproductive failure. Prior clinical studies suggest an inadequate endometrial growth and development of the endometrium, leading to a lesser endometrial thickness.