In primary mammalian cells, oncogenic ras induces premature senescence, depending on an active MEKextracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway. It has been unclear how activation of the mitogenic MEK-ERK pathway by ras can confer growth inhibition. In this study, we have found that the stress-activated MAPK, p38, is also activated during the onset of ras-induced senescence in primary human fibroblasts. Constitutive activation of p38 by active MKK3 or MKK6 induces senescence. Oncogenic ras fails to provoke senescence when p38 activity is inhibited, suggesting that p38 activation is essential for ras-induced senescence. Furthermore, we have demonstrated that p38 activity is stimulated by ras as a result of an activated MEK-ERK pathway. Following activation of MEK and ERK, expression of oncogenic ras leads to the accumulation of active MKK3/6 and p38 activation in a MEK-dependent fashion and subsequently induces senescence. Active MEK1 induces the same set of changes and provokes senescence relying on active p38. Therefore, oncogenic ras provokes premature senescence by sequentially activating the MEK-ERK and MKK3/6-p38 pathways in normal, primary cells. These studies have defined the molecular events within the ras signaling cascade that lead to premature senescence and, thus, have provided new insights into how ras confers oncogenic transformation in primary cells.

Using a large consortium of undergraduate students in an organized program at the University of California, Los Angeles (UCLA), we have undertaken a functional genomic screen in the Drosophila eye. In addition to the educational value of discovery-based learning, this article presents the first comprehensive genomewide analysis of essential genes involved in eye development. The data reveal the surprising result that the X chromosome has almost twice the frequency of essential genes involved in eye development as that found on the autosomes.

Thirst is a motivational state that drives behaviors to obtain water for fluid homeostasis. We identified two types of central brain interneurons that regulate thirsty water seeking in Drosophila, that we term the Janu neurons. Janu-GABA, a local interneuron in the subesophageal zone, is activated by water deprivation and is specific to thirsty seeking. Janu-AstA projects from the subesophageal zone to the superior medial protocerebrum, a higher order processing area. Janu-AstA signals with the neuropeptide Allatostatin A to promote water seeking and to inhibit feeding behavior. NPF (Drosophila NPY) neurons are postsynaptic to Janu-AstA for water seeking and feeding through the AstA-R2 galanin-like receptor. NPF neurons use NPF to regulate thirst and hunger behaviors. Flies choose Janu neuron activation, suggesting that thirsty seeking up a humidity gradient is rewarding. These findings identify novel central brain circuit elements that coordinate internal state drives to selectively control motivated seeking behavior.

Existing therapeutic strategies for breast cancer are limited by tumor recurrence and drug-resistance. Antioxidant plant-derived compounds such as flavonoids reduce adverse outcomes and have been identified as a potential source of antineoplastic agent with less undesirable side effects. Here, we describe the novel regulation of fatty-acid synthase (FASN), the key enzyme in de novo fatty-acid synthesis, whereby Vitis vinifera L. cv Vermentino leaf hydroalcoholic extract lowers its protein stability that is regulated by small ubiquitin-like modifier (SUMO)ylation. The phenolic compounds characterization was performed by liquid chromatography–mass spectrometry (LC–MS), whereas mass spectrometry (LC–MS/MS), Western blotting/co-immunoprecipitation (Co-IP) and RT-PCR, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clonogenicity assays, and FACS analysis were used to measure the expression of targets and tumorigenicity. Vermentino extract exhibits antitumorigenic effects, and we went on to determine that FASN and ubiquitin-conjugating enzyme 9 (UBC9), the sole E2 enzyme required for SUMOylation, were significantly reduced. Moreover, FASN was found SUMOylated in human breast cancer tissues and cell lines, and lack of SUMOylation caused by SUMO2 silencing reduced FASN protein stability. These results suggest that SUMOylation protects FASN against proteasomal degradation and may exert oncogenic activity through alteration of lipid metabolism, whereas Vermentino extract inhibits these effects which supports the additional validation of the therapeutic value of this compound in breast cancer.

Background: Existing therapeutic strategies for breast cancer are limited by tumor recurrence and drug-resistance. Several epidemiological studies indicate that antioxidant plant-derived compounds such as flavonoids reduce adverse outcomes and have been identified as a potential source of antineoplastic agent with less undesirable side effects. Activation of lipid metabolism is an early event in carcinogenesis and a central hallmark in breast cancer. In fact, inhibition of fatty-acid synthesis in breast cancer results in cytotoxicity that triggers apoptosis. Here, we describe the novel regulation of lipid metabolism in breast cancer cells whereby the protein stability and degradation of fatty-acid synthase (FASN), the key enzyme in de novo fatty-acid synthesis, is regulated by SUMOylation. Methods: The phenolic characterization were analyzed by Liquid Chromatography-Mass Spectrometry (LCMS). Profile protein contents was evaluated by Mass Spectrometry (LC-MS/MS). The experiments were performed using MCF7, SKBR-3 human carcinoma cell lines and MCF-12A breast epithelial cell line treated with Vermentino hydroalcoholic extract in dose and time course responses. Protein and mRNA levels were analyzed by western blotting/Co-immunoprecipitation (Co-IP) and RT-PCR, respectively. The number of viable cells and the cell-surviving has been detected by MTT and clonogenicity assays. Apoptotic induction was determined by Flow Cytometric assay using Annexin V-FITC and sorted by A FACSC analysis.Results: We first tested the potential antitumorigenic effects of Vitis vinifera L. cv. Vermentino leaf hydroalcoholic extract in MCF-7 and SKBR-3 breast cancer cell lines and found that this compound demonstrated cytotoxic effects. We went on to determine that FASN and UBC9, the sole E2 enzyme required for SUMOylation, were significantly reduced by treatment with the Vermentino extract.Moreover, we found that FASN was SUMOylated in human breast cancer tissues and cell lines. Finally, lack of SUMOylation caused by SUMO2 silencing reduced FASN protein stability.Conclusion: Altogether, these results suggest that SUMOylation protects FASN against proteasomal degradation and may exert oncogenic activity through alteration of lipid metabolism in breast cancer.Importantly, we found that these effects were significantly inhibited by treatment with Vermentino leaf extract, which supports the additional validation of the therapeutic value of this compound. BackgroundBreast cancer is the most common malignant cancer in females worldwide (1). The existing therapeutic strategies for breast cancer, which include surgery, endocrine therapy, and chemotherapy, are limited by tumor recurrence and drug-resistance (2). Therefore, novel approaches are needed to enhance the efficacy of existing therapeutic agents and to improve current clinical protocols.Adjuvant therapies often attempt to induce cytotoxicity in tumor cells. As tumor cells are known to rely on alternate metabolic processes, such as de novo fatty-acid synthesis, these pathways harbor many pote...