Autophagy and intermittent fasting: the connection for cancer therapy?

Cancer is a leading cause of death worldwide, and its incidence is continually increasing. Although anticancer therapy has improved significantly, it still has limited efficacy for tumor eradication and is highly toxic to healthy cells. Thus, novel therapeutic strategies to improve chemotherapy, radiotherapy and targeted therapy are an important goal in cancer research. Macroautophagy (herein referred to as autophagy) is a conserved lysosomal degradation pathway for the intracellular recycling of macromolecules and clearance of damaged organelles and misfolded proteins to ensure cellular homeostasis. Dysfunctional autophagy contributes to many diseases, including cancer. Autophagy can suppress or promote tumors depending on the developmental stage and tumor type, and modulating autophagy for cancer treatment is an interesting therapeutic approach currently under intense investigation. Nutritional restriction is a promising protocol to modulate autophagy and enhance the efficacy of anticancer therapies while protecting normal cells. Here, the description and role of autophagy in tumorigenesis will be summarized. Moreover, the possibility of using fasting as an adjuvant therapy for cancer treatment, as well as the molecular mechanisms underlying this approach, will be presented

Avaliação da autofagia e apoptose em astrócitos imortalizados que superexpressam a proteína alfa-sinucleína selvagem e suas mutantes a30p e a53t

Dados abertos - Sucupira - Teses e dissertações (2013 a 2016

Desenvolvimento, Caracterização E Estudos Da Autofagia E Apoptose Em Modelo Celular De Doença De Parkinson

Parkinson"S Disease (Pd) Is A Chronic Progressive Disease Characterized By The Death Of Dopaminergic Neurons In The Substantia Nigra Pars Compacta (Snpc) In The Brain Region. The Main Pathological Feature Of Pd Is The Presence Of Cytoplasmic Protein Aggregates Called Lewy Bodies, Whose Main Component Is The Protein "-Synuclein ("-Syn). It Is A Protein With Functions That Remain Poorly Understood, However It Might Act In Exocytosis Of Neurotransmitters Vesicles And In Regulation Of Mitochondrial Physiology And Morphology. This Protein Is Predominantly Found In Wild Type (Wt) Conformation, However Mutations In The Gene That Encodes "-Synuclein (Snca) Have Been Described As Generating Mutant Species, Such As A30p And A53t, Both Of Which Related To Autosomal Dominant Cases Of Pd. The Accumulation And Aggregation Of These Proteins In The Cytoplasm Of Neurons May Cause Mitochondrial Dysfunction, Cells Stress, And Cell Death. Transglutaminase-2 (Tg2) Is An Enzyme That Demonstrates An Important Role In The GenerationA Doença De Parkinson (Dp) É Uma Doença Crônica Progressiva, Caracterizada Pela Morte De Neurônios Dopaminérgicos Da Substantia Nigra Pars Compacta Do Cérebro. A Principal Característica Patológica Da Dp É A Presença De Agregados Proteicos Citoplasmáticos, Chamados Corpos De Lewy, Sendo O Principal Componente A Proteína "-Sinucleína ("-Sin). Sua Função Ainda Pouco Compreendida, Acredita-Se Que Atue Na Exocitose De Vesículas De Neurotransmissores E Na Regulação Da Fisiologia E Morfologia Mitocondrial. A "-Sin É Comumente Encontrada Na Sua Forma Selvagem (Wt), Contudo Mutações No Gene Snca, Leva A Formação De Proteínas Mutantes, Como A A30p E A53t, Ambas Ligadas A Casos Autossômicos Dominantes Da Dp. O Acúmulo E Agregação Destas Proteínas No Citoplasma Dos Neurônios Afetados Podem Promover Estresse Celular, Disfunções Mitocondriais E Morte Neuronal. A Enzima Transglutaminase-2 (Tg2) Demonstra Ter Papel Importante Na Formação De Agregados Proteicos Em Processos Neurodegenerativos, Uma Vez Que Pode Mediar ReaçõesDados abertos - Sucupira - Teses e dissertações (2018

Effects of Aging in the Striatum and Substantia Nigra of a Parkinson's Disease Animal Model

Aging is a multifactorial process associated with functional deficits, and the brain is more prone to developing chronic degenerative diseases such as Parkinson's disease. Several groups have tried to correlate the age-related ultrastructural alterations to the neurodegeneration process using in vivo pharmacological models, but due to the limitations of the animal models, particularly in aged animals, the results are difficult to interpret. In this work, we investigated neurodegeneration induced by rotenone, as a pharmacological model of Parkinson's disease, in both young and aged Wistar rats. We assessed animal mobility, tyrosine hydroxylase staining in the substantia nigra pars compacta (SNpc), and TdT-mediated dUTP-biotin nick end labeling-positive nuclei and reactive oxygen species production in the striatum. Interestingly, the mobility impairment, dopaminergic neuron loss, and elevated number of apoptotic nuclei in the striatum of aged control rats were similar to young rotenone-treated animals. Moreover, we observed many ultrastructural alterations, such as swollen mitochondria in the striatum, and massive lipofuscin deposits in the SNpc of the aged rotenone-treated animals. We conclude that the rotenone model can be employed to explore age-related alterations in the ontogeny that can increase vulnerability in the striatum and SNpc, which may contribute to Parkinson's disease pathogenesis.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo [FAPESP]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico [CNPq]Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Univ Fed Sao Paulo, Dept Biol Sci, 275 Arthur Ridel St, BR-09972270 Diadema, SP, BrazilUniv Fed Sao Paulo, Dept Pharmacol, Sao Paulo, BrazilUniv Fed Sao Paulo, Ctr Electron Microscopy, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Biol Sci, 275 Arthur Ridel St, BR-09972270 Diadema, SP, BrazilUniv Fed Sao Paulo, Dept Pharmacol, Sao Paulo, BrazilUniv Fed Sao Paulo, Ctr Electron Microscopy, Sao Paulo, BrazilFAPESP: 2012/08273-3FAPESP: 2013/20073-2Web of Scienc

Lack of Autophagy Induction by Lithium Decreases Neuroprotective Effects in the Striatum of Aged Rats

The pharmacological modulation of autophagy is considered a promising neuroprotective strategy. While it has been postulated that lithium regulates this cellular process, the age-related effects have not been fully elucidated. Here, we evaluated lithium-mediated neuroprotective effects in young and aged striatum. After determining the optimal experimental conditions for inducing autophagy in loco with lithium carbonate (Li2CO3), we measured cell viability, reactive oxygen species (ROS) generation and oxygen consumption with rat brain striatal slices from young and aged animals. In the young striatum, Li2CO3 increased tissue viability and decreased ROS generation. These positive effects were accompanied by enhanced levels of LC3-II, LAMP 1, Ambra 1 and Beclin-1 expression. In the aged striatum, Li2CO3 reduced the autophagic flux and increased the basal oxygen consumption rate. Ultrastructural changes in the striatum of aged rats that consumed Li2CO3 for 30 days included electrondense mitochondria with disarranged cristae and reduced normal mitochondria and lysosomes area. Our data show that the striatum from younger animals benefits from lithium-mediated neuroprotection, while the striatum of older rats does not. These findings should be considered when developing neuroprotective strategies involving the induction of autophagy in aging

Reduction in skeletal muscle fibrosis of spontaneously hypertensive rats after laceration by microRNA targeting angiotensin II receptor.

Regeneration of injured skeletal muscles is affected by fibrosis, which can be improved by the administration of angiotensin II (AngII) receptor (ATR) blockers in normotensive animals. However, the role of ATR in skeletal muscle fibrosis in hypertensive organisms has not been investigated yet. The tibialis anterior (TA) muscle of spontaneously hypertensive (SHR) and Wistar rats (WR) were lacerated and a lentivector encoding a microRNA targeting AngII receptor type 1 (At1) (Lv-mirAT1a) or control (Lv-mirCTL) was injected. The TA muscles were collected after 30 days to evaluate fibrosis by histology and gene expression by real-time quantitative PCR (RT-qPCR) and Western blot. SHR's myoblasts were analyzed by RT-qPCR, 48 h after transduction. In the SHR's TA, AT1 protein expression was 23.5-fold higher than in WR without injury, but no difference was observed in the angiotensin II receptor type 2 (AT2) protein expression. TA laceration followed by suture (LS) produced fibrosis in the SHR (23.3±8.5%) and WR (7.9±1.5%). Lv-mirAT1 treatment decreased At1 gene expression in 50% and reduced fibrosis to 7% 30 days after. RT-qPCR showed that reduction in At1 expression is due to downregulation of the At1a but not of the At1b. RT-qPCR of myoblasts from SHR transduced with Lv-mirAT1a showed downregulation of the Tgf-b1, Tgf-b2, Smad3, Col1a1, and Col3a1 genes by mirAT1a. In vivo and in vitro studies indicate that hypertension overproduces skeletal muscle fibrosis, and AngII-AT1a signaling is the main pathway of fibrosis in SHR. Moreover, muscle fibrosis can be treated specifically by in loco injection of Lv-mirAT1a without affecting other organs

Autophagy and intermittent fasting: the connection for cancer therapy?

Cancer is a leading cause of death worldwide, and its incidence is continually increasing. Although anticancer therapy has improved significantly, it still has limited efficacy for tumor eradication and is highly toxic to healthy cells. Thus, novel therapeutic strategies to improve chemotherapy, radiotherapy and targeted therapy are an important goal in cancer research. Macroautophagy (herein referred to as autophagy) is a conserved lysosomal degradation pathway for the intracellular recycling of macromolecules and clearance of damaged organelles and misfolded proteins to ensure cellular homeostasis. Dysfunctional autophagy contributes to many diseases, including cancer. Autophagy can suppress or promote tumors depending on the developmental stage and tumor type, and modulating autophagy for cancer treatment is an interesting therapeutic approach currently under intense investigation. Nutritional restriction is a promising protocol to modulate autophagy and enhance the efficacy of anticancer therapies while protecting normal cells. Here, the description and role of autophagy in tumorigenesis will be summarized. Moreover, the possibility of using fasting as an adjuvant therapy for cancer treatment, as well as the molecular mechanisms underlying this approach, will be presented

Gene expression analysis of myoblasts from SHR after treatment with Lv-mirAT1a.

<p>(A) Expression of myogenic genes in primary culture of SHR myoblasts from passages 2, 4, and 6. Cell line L6 was used as a control. (B) SHR myoblasts (passage 4) were transduced with the Lv-mirAT1a or Lv-mirCTL lentivectors, and gene expression was analyzed 48 h later by RT-qPCR. n = 3 rats per group. Bars represent mean and standard deviation. * p<0.05.</p

Fibrogenic gene expression profile in SHR and WR myoblasts after treatment with AngII.

<p>Expression of fibrogenic genes in primary culture of SHR (A) or WR (B) myoblasts (passage 4) by RT-qPCR, 24 h after treatment with AngII (100 nM). n = 6 per group. Bars represent mean and standard deviation. * p<0.05, **p<0.01, ***p<0.001, ****p<0.0001.</p

Effect of Lv-mirAT1a on laceration-injured skeletal muscle.

<p>(A) The L6 myogenic cell line was transduced with the Lv-mirAT1a or Lv-mirCTL lentivectors (MOI = 10), and the AT1a gene expression was evaluated 48 h later by RT-qPCR. (B) Lentivectors were injected into the TA muscle from SHR soon after LS lesion. Later (30 days), the animals were euthanized for TA muscle weight quantification, (C) histology (scale bar = 100 μm), (D) determination of the fibrotic area using data from Fig B, (E) expression of the AT1 protein gene by Western blot analysis, and (F) expression of the <i>Agtr1a</i>, (G) <i>Agtr1b</i> and (H) <i>Agtr2</i> genes by RT-qPCR analysis. n = 5 rats per group. Values represent mean and standard deviation. TA: <i>Tibialis anterior</i>; SHR: spontaneously hypertensive rat; CTL: SHR without injury; PR: Picrosirius Red; HE: hematoxylin-eosin stain; * p<0.05.</p