Natural compounds in the regulation of proteostatic pathways: An invincible artillery against stress, ageing, and diseases

Cells have different sets of molecules for performing an array of physiological functions. Nucleic acids have stored and carried the information throughout evolution, whereas proteins have been attributed to performing most of the cellular functions. To perform these functions, proteins need to have a unique conformation and a definite lifespan. These attributes are achieved by a highly coordinated protein quality control (PQC) system comprising chaperones to fold the proteins in a proper three-dimensional structure, ubiquitin-proteasome system for selective degradation of proteins, and autophagy for bulk clearance of cell debris. Many kinds of stresses and perturbations may lead to the weakening of these protective cellular machinery, leading to the unfolding and aggregation of cellular proteins and the occurrence of numerous pathological conditions. However, modulating the expression and functional efficiency of molecular chaperones, E3 ubiquitin ligases, and autophagic proteins may diminish cellular proteotoxic load and mitigate various pathological effects. Natural medicine and small molecule-based therapies have been well-documented for their effectiveness in modulating these pathways and reestablishing the lost proteostasis inside the cells to combat disease conditions. The present article summarizes various similar reports and highlights the importance of the molecules obtained from natural sources in disease therapeutics.

Screening of differentially expressed miRNAs in A549 cells induced by 17-AAG-M and its effect on radio-sensitivity / 中华放射肿瘤学杂志

Objective:To screen 17-AAG-M-induced differentially expressed miRNAs in human non-small cell lung cancer (NSCLC) A549 cells under X-ray and evaluate its effect on radio-sensitivity.Methods:A549 cells were treated with 17-AAG-M and 4 Gy. Total RNA was extracted for microarray screening. The expression of the miRNAs of interest in the tumor was observed by public database. The target miRNAs were analyzed by using GO and KEGG pathways, and verified by qPCR. The effect of target miRNAs on the survival rate and proliferation of A549 cells under X-ray was evaluated by MTT and clone formation assays. The radio-sensitivity of the target miRNAs was analyzed by the single-hit multi-target model formula.Results:20 differentially expressed miRNAs were screened. The down-regulated hsa-miR-30a-3p showed a close correlation with lung cancer in the database. It was involved with 50 biological processes including cell proliferation and affected the MAPK signaling pathway, cancer-related pathways and cell cycle, etc. Compared with the 17-AAG-M group, the relative expression level of hsa-miR-30a-3p under the action of 17-AAG-M and X-ray was down-regulated from 2.42 to 0.16. hsa-miR-30a-3p inhibited the survival rate of A549 cells (survival rate: 78.52%) and further decreased to 69.00% under X-ray. Up-regulation of hsa-miR-30a-3p expression inhibited the proliferation of tumor cells and increased the radio-sensitivity of A549 cells. The radio-sensitization ratio was 1.18. The above performance became more obvious under the action of 17-AAG-M.Conclusions:In A549 cells, hsa-miR-30a-3p is differentially expressed under the action of 17-AAG-M and X-ray. Moreover, up-regulation of the expression level of hsa-miR-30a-3p in A549 cells can reduce the viability and proliferation of tumor cells, and increase the radio-sensitivity of tumor cells. The inhibition effect of X-ray combined with 17-AAG-M upon tumors can be strengthened.

Inhibitory effect of 17AAG-cypate polymer micelles on A549 cell xenografts in nude mice in vivo / 中华放射肿瘤学杂志

Objective@#To investigate the inhibitory effect of 17AAG-Cypate micelles on the non-small cell lung cancer A549 cells in nude mice and to explore its possible mechanism.@*Methods@#A549 lung adenocarcinoma tumor-bearing nude mice were established. The nude mice were treated with saline ( saline group), X-ray (X-ray group), 17AAG micelles+ X-ray (17AAG-M/X group) and 17AAG-Cypate micelles+ laser/X-ray (17AAG-Cypate-M/L+ X group), respectively. The growth of xenograft tumors in different groups was measured on a regular basis to delineate the growth curve. The expression of proliferating cell nuclear antigen (PCNA) was measured by immunohistochemistry. The microvascular density was detected. The apoptosis of xenograft tissues was observed by TUNEL staining. The expression levels of p-ERK1/2 and p-AKT were quantitatively measured by Western blot.@*Results@#Compared with the saline group, varying degrees of inhibition of tumor growth were observed in the X-ray, 17AAG-M/X-ray and 17AAG-Cypate-M/L+ X groups, particularly in the 17AAG-Cypate-M/L+ X group (all P<0.05). In all groups, the expression levels of PCNA were significantly down-regulated (all P<0.05), the microvascular density was remarkably reduced (all P<0.05) and the expression levels of p-ERK1/2 and p-AKT were considerably down-regulated (all P<0.05).@*Conclusions@#17AAG-Cypate micelles can inhibit the growth of human non-small cell lung cancer in nude mice, probably by reducing the activity of p-ERK1/2 and p-AKT, thereby weakening the activation of the MAPK-ERK and PI3K-AKT signaling pathways.

Effects of 17-AAG on neurons apoptosis induced by oxygen-glucose deprivation and recovery / 解放军医学杂志

Objective To explore the role and mechanism of 17-allylamino-17-demethoxygeldanamycin (17-AAG) in neurons apoptosis induced by oxygen-glucose deprivation and recovery (OGD/R).Methods Primary rat neurons were cultivated in vitro,and OGD/R model was reproduced.Neurons were exposed to OGD for 0.5h,1h and 2h,and then reperfusion for 24h,the effect of OGD/R on neurons apoptosis was detected by TUNEL assay.On OGD/R,neurons were treated with different concentrations of 17-AAG (0.5,1.0 and 2.0μmol/L),and the effect of 17-AAG on OGD/R treated neurons apoptosis was detected by TUNEL assay.Western blotting was performed to detect the expression of heat shock protein 70 (HSP70).HSP70 interference lentivirus was then constructed.The effect of HSP70 interference on the neurons apoptosis treated with OGD/R and 17-AAG was detected by TUNEL assay.Results OGD/R significantly induced neurons apoptosis,and the rate of neurons apoptosis increased with the increase of OGD time.17-AAG obviously inhibited the neurons apoptosis induced by OGD/R,and the higher the 17-AAG concentration,the more obvious the inhibition.OGD/R significantly suppressed the expression of HSP70 protein in neurons,and 17-AAG obviously reversed the inhibition of HSP70 protein expression induced by OGD/R.However,HSP70 lentivirus interference markedly reversed the protective effect of 17-AAG on OGD/R treated neurons.Conclusion 17-AAG may inhibit the apoptosis of OGD/R treated neurons by up-regulating HSP70.

Effect of 17AAG-cypate polymer micelle on radio-sensitivityof A549 cells / 中华放射肿瘤学杂志

Objective To investigate the radiosensitizing effect of 17AAG-cypate micelles on human non-small cell lung cancer A549 cells and its possible mechanism.Methods (1) A single-hit multi-target model formula was used to analyze the radiosensitizing effects of 17AAG-M and 17AAG-cypate-M.(2) The effects of 17AAG-cypate-M on the viability of A549 cells under laser and X-ray irradiation were analyzed by MTT assay.(3) The effect of the drugs on the cell senescence was observed by β-galactosidase staining assay.(4) The effects of different treatment conditions on DNA damage repair were analyzed by γ-H2AX immunofluorescence staining assay.(5) The expression of p-Erk1/2 and p-Akt was measured by Western blot.The paired t test was used for analyzing the differences between groups.Results Compared with the X-ray irradiation group,the X-ray+17AAG-cypate-M group had a lower mean lethal dose and a sensitization enhancement ratio greater than 1,indicating that 17AAG-cypate-M had a radiosensitizing effect.Compared with the 17AAG-M group,the 17AAG-cypate-M group showed significantly lower cell viability (P<0.01),a significantly higher percentage of aging cells (P<0.01),and significantly further delayed DNA damage repair (P<0.01).And the 17AAG-cypate-M group had lower expression of p-Erk1/2 and p-Akt than the 17AAG-M group.Conclusions Compared with 17AAG-M,17AAG-cypate-M has a higher radiosensitizing effect on A549 cells.The mechanism might be inducing the cell senescence,delaying DNA damage repair,and inhibiting the expression of p-Erk1/2 and p-Akt.

Expression of HSP90 in cholangiocarcinoma tissues and cells and the effect of 17-AAG on cholangiocarcinoma cell line / 中国现代普通外科进展

Objeetive:To investigate the expression of HSP90 in cholangiocarcinoma tissues and cells,and the effect of 17-AAG on cholangiocarcinoma cell line.Methods:Forty patients with cholangiocarcinoma admitted to our hospital from July 2015 to July 2016 were selected as study subjects.Expression of HSP90 in cholangiocarcinoma tissues,paracancerous tissues and normal tissues was detected respectively.Cholangiocarcinoma cell lines were treated with different concentrations of 17-AAG,and expression of HSP90 and its effect protein HIF-1 α was detected.R esults:The total positive rate in cholangiocarcinoma tissues (82.5％) was higher than paracancerous tissues (35.0％) and normal tissues (20.0％)(all P＜0.05).The strong positive expression rate in cholangiocarcinoma tissues(37.5％) was higher than paracancerous tissues(10.0％) and normal tissues (5.0％)(all P＜0.05).There was no significant correlation between expression of HSP90 in cholangiocarcinoma tissues and invasion depth,lymph node metastasis (P＞0.05),but there was a significant correlation with TNM stage and tumor diameter (P＜0.05).With the increase of treatment concentration of 17-AAG,HSP90 α / β-actin and HIF-1 α / β-actin decreased,and there were significant differences in expression of HSP90α and its effect protein HIF-1 α in cholangiocarcinoma cell lines under different treatment concentrations (P＜0.05).Conclusion:HSP90 is highly expressed in cholangiocarcinoma tissues and cells and its expression is related to clinical stage and tumor diameter.17-AAG can down regulates the expression of HSP90 α and HIF-1 α in TE-1 cells,which plays a certain guiding role in clinical treatment.

Avaliação do 17-AAG como agente leishmanicida e seu mecanismo de ação na indução da morte de parasitos do gênero leishmania spp / 17-AAG assessment as leishmanicidal agent and its mechanism of action for induction of parasites of the Leishmania genus death spp

A leishmaniose é uma doença endêmica no Brasil causada por parasitos protozoários do gênero Leishmania. A quimioterapia continua sendo a forma mais efetiva de tratamento com os antimoniais pentavalentes sendo usados há mais de 70 anos como a primeira linha de tratamento. O uso deste e de outros fármacos apresenta efeitos adversos graves, os esquemas terapêuticos empregados são desconfortáveis, além de relatos do aumento de casos de resistência. A proteína de choque térmico 90 (HSP90) é um membro da família das chaperonas presente em células eucarióticas e bactérias. Essa proteína é fundamental para o dobramento e estabilização de diferentes proteínas, chamadas genericamente de proteínas cliente. Essa chaperona vem sendo considerada um importante alvo molecular para o tratamento de diferentes doenças parasitárias. Nessa tese, o inibidor específico da atividade ATPásica da HSP90, o 17-allilamino-17-demethoxigeldanamicina (17- AAG) foi testado em parasitos do gênero Leishmania. Inicialmente, avaliamos o efeito em cultura axênica e observamos que o 17-AAG causa a morte desses parasitos em concentrações inferiores às necessárias para causar a morte de macrófagos. Observamos também que o tratamento com 17-AAG promove a morte intracelular dos parasitos em concentrações que variam de 25 a 500 nM nos tempos de 24 e 48 h...

Leishmaniases are endemic disease in Brazil caused by protozoan parasites from the genus Leishmania. Chemotherapy remains the most effective way of treatment and pentavalent antimonials, used for more than 70 years, remaining as first choice drugs for leishmaniasis treatment. The use of this and other drugs causes severe side effects, therapeutic regimens employed for leishmaniasis treatment are unpleasant, besides an increase number of resistance cases. The Heat Shock Protein 90 (HSP90) is a member of the chaperone family present in bacteria and eukaryotic cells. This protein is essential for the folding and stabilization of different proteins, known as client proteins. This chaperone has been considered an important molecular target for the treatment of different parasitic diseases. In this thesis, the specific inhibitors of the ATPase activity from the HSP90, 17-allylamino- 17-demethoxygeldanamycin (17-AAG), were tested against parasites from the genus Leishmania. First we evaluated its effect on axenic culture and observed that 17- AAG induces parasite cell death in lowerconcentrations than those needed to induce macrophage cell death. We also observed that 17-AAG intracellular parasite death in concentrations ranging from 25 to 500 nM after 24 or 48 h...

Role of 17-AAG in inducing apoptosis and cell cycle arrest of HCT-15 cells / 中国病理生理杂志

AIM:To investigate the effects of 17-AAG on apoptosis and cell cycle of HCT-15 cells and to clar-ify the related mechanisms .METHODS: MTT method was employed to evaluate the inhibitory effects of 17-AAG with Aifferent time and different doses on the proliferation of HCT-15 cells.The cells were stained with Annexin V-FITC/propid-iumiodide and measured by flow cytometry .The expression of STAT3, cyclin D1, Cyt C, caspase 9 and caspase 3 at mR-NA and protein levels was determined by RT-PCR and Western blotting .RESULTS:Treatment with 17-AAG at concentra-tion of 1.25~20 mg/L for 24 h and 48 h significantly inhibited the activity of HCT-15 cells at both time-and concentra-tion-dependent manners .Treatment with 17-AAG at concentrations of 0.425, 0.85 and 1.7 mg/L for 48 h significantly in-duced apoptosis and cell cycle arrest of HCT-15 cells.The exposure of 17-AAG at concentrations of 0.425, 0.85 and 1.7 mg/L for 48 h to the HCT-15 cells significantly down-regulated the expression of STAT 3 and cyclin D1 at mRNA and pro-tein levels, but up-regulated Cyt C, caspase 9 and caspase 3 mRNA and protein in a concentration-dependent manner . CONCLUSION:17-AAG inhibits the cell activity , induces apoptosis and G 1 arrest by down-regulating the expression of cyclin D1, and promoting the mitochondria apoptosis through STAT 3 pathway.

Mechanisms of imatinib resistance on K562 and K562A02 reversing by 17-AAG / 中国药学杂志

OBJECTIVE: To observe the effect of imatinib (IM) combined with 17-allylamino-17-demethoxygeldanamycin (17-AAG) on the growth inhibition and apoptosis of two homologous chronic myeloid leukemic (CML) cell lines K562 and K562A02, and to evaluate their sensitivity or resistance to imatinib.

Avaliação in vitro da expressão das proteínas PTEN, Akt, Mdm2 e p53 em células de carcinoma epidermóide de cabeça e pescoço submetidas a ação de EGF e 17-AAG / In vitro evaluation of the expression of PTEN protein, Akt, Mdm2 and p53 in cells of squamous cell carcinoma of head and neck under the action of EGF and 17-AAG

O carcinoma epidermóide de cabeça e pescoço é responsável por 90% das neoplasias malignas, nesta região. Molecularmente, inúmeras vias de sinalização, ainda não muito bem compreendidas, são responsáveis pelo seu crescimento e invasão para tecidos vizinhos, além de metástases para órgãos distantes. Este trabalho destinou-se a avaliar o crosstalk entre as vias de sinalização do PTEN, Akt, Mdm2 e p53 em quatro linhagens de células de carcinoma epidermóide (HN6, HN19, HN30 e HN31) e queratinócitos imortalizados (HaCat), estimulados com EGF (fator de crescimento epitelial) e 17-AAG. Para observar a localização e os níveis de PTEN, Akt, Mdm2 e p53 nos diferentes compartimentos celulares estas proteínas foram localizadas e quantificadas no interior celular através das técnicas de imunofluorescência e western blot, respectivamente. Os resultados mostraram que a ativação da via do PI3K/Akt, pelo EGF, promoveu a proliferação celular, sendo HN31 a linhagem celular de melhor resposta proliferativa. Quando as células foram tratadas com 17-AAG a linhagem HN31 foi a que melhor traçou um perfil apoptótico com diminuição dos níveis de Akt, ausência de Mdm2 e aumento dos níveis de PTEN e p53. As linhagens celulares HN6 e HN19 continuaram apresentando níveis significativos de Akt e Mdm2, o que sugere um potencialmais agressivo devido a manutenção do comportamento proliferativo e anti-apoptótico destas linhagens.

Head and neck squamous cell carcinoma (HNSCC) represents 90% of all head and neck malignancies. Cancer growth, invasion and metastasis are due to several signaling pathways that, unfortunately, are not completely understood. The aim of this study was the crosstalk evaluation among PTEN, Akt, Mdm2 and p53 signaling pathways in four different HNSCC cell lines (HN6, HN19, HN30 and HN31) and HaCat cell line (immortalized keratinocytes), all of than treated with 10ng/ml EGF (epidermal growth factor) and 2ìM 17-AAG. Western blot and imunofluorescence were performed in order to analyze PI3K/Akt signaling key target proteins: PTEN, Akt, Mdm2 and p53. Treatment of HNSCC cell lines with EGF resulted in activation of the PI3K/Akt pathway and enhanced cell proliferation. The results showed higher proliferative activity in HN31 cell line. The treatment of HNSCC cell lines with 17-AAG inhibited the proliferation in various levels. HN31 cell lines expressed PTEN and p53 in high levels and low expression for Akt and Mdm2 proteins. These findings suggest that 17-AAG can induce p53-dependent apoptosis in HN31 cell lines. On the contrary, HN6 and HN19 cell lines displayed high levels of Akt and Mdm2 proteins, resulting in decreased apoptosis and increased aggressive potential.