Objective To investigate the effects and mechanism of 3-methyladenine （3-MA， an autophagy inhib-itor） on the apoptosis of hepatocellular carcinoma cell line SMMC7721 induced by 5-fluorouracil （5-FU）. Methods The autophagy was observed using fluorescent microscope by monodansyicadaverin （MDC） staining. The viability of SMMC-7721 cell induced by 5-FU was measured using CCK8 assay before and after autophagy inhibited by 3-MA， meanwhile the apoptosis of SMMC7721 cell was determined via AnnexinⅤ/PI assay. The light chain 3 protein （LC3， the autophagy specific protein） and caspase-3， PARP protein were detected by Western blot. Results The autophagy of SMMC7721 cell could be induced by 5-FU after treatment for 48 h， the cell survival rate was （60.73±2.65）%， and the apoptosis rate was （40.42±2.34）%. Compared with the group of 5-FU treatment， the survival rate of SMMC7721 cell in the combination of 5-FU and 3-MA after treatment for 48 h decreased to （42.31±1.32）% （P＜0.01）， and the apoptosis rate increased to （60.92±2.99）% （P＜0.01）， meanwhile the expressions of LC3-Ⅱ， activation fragment of caspase-3， and cleavage frag-ment of PARP significantly increased （P＜0.01）. Conclusions Autophagy is a protective phenomenon during the SMMC7721 cell line apoptosis induced by 5-FU， and autophagy inhibition may enhance the sensitivity of SMMC7721 cell line to 5-FU treatment， which is probably associated with the activation of caspase-3 and cleavage of PARP. Therefore， autophagy inhibition could be a promising strategy for adjuvant chemotherapy in hepatocellular carcinoma.
Objective To realize the research progress of regulating the endoplasmic reticulum stress response to inhibit autophagy in tumor cells. Method The literatures about regulating the endoplasmic reticulum stress response to inhibit autophagy in tumor cells were reviewed. Result In the endoplasmic reticulum stress response induced by the release of calcium and accumulation of unfolded proteins, autophagy can be activated by several pathways, and to regulate physiological and pathological processes. Conclusion Further research about the endoplasmic reticulum stress response in tumor cells need to be done to regulate the response factors to inhibit autophagy.
ObjectiveTo investigate the role of autophagy-lysosomal system in skeletal muscle atrophy in rats with chronic obstructive pulmonary disease (COPD). MethodsPassive cigarette smoking was used to establish COPD model. The mRNA and protein expression of FOXO transcription factor and autophagy-related genes Bnip3, Beclin1, p62, MAP-LC3Ⅱ/Ⅰ, Atg5 in extensor digitorum longus of rats were measured by real time PCR and Western blot. The changes of extensor digitorum longus tissue sections and lung tissue sections in the experimental group rats were observed under transmission electron microscopy. ResultsCompared with the control group, the mRNA expression of FOXO transcription factor and autophagy-related genes Bnip3, Beclin1, p62, Atg5 in extensor digitorum longus of the experimental group group rats was significantly increased (all P<0.05, as for Bnip3, the P value between two groups <0.01); The mRNA expression of MAP-LC3Ⅱ/Ⅰwas not significantly different between two groups (P>0.05). The protein expression of FOXO, Bnip3, Beclin1, p62, MAP-LC3Ⅱ/Ⅰ, Atg5 significantly increased in the COPD group (all P<0.05, as for Bnip3, MAP-LC3Ⅱ/Ⅰ, Beclin1, the P values between two groups <0.01). Compared with the control group, autolysosome in extensor digitorum longus tissue sections of the experimental group rats increased and lung tissue fibrosis and more inflammatory cells were observed in lung tissue sections of the experimental group rats under transmission electron microscopy. ConclusionThe mRNA and protein expressions of FOXO transcription factor and autophagy-related genes in extensor digitorum longus increase significantly in the experimental group rats, suggesting that the activity of autophagy-lysosomal system, which may be one mechanism of skeletal muscle atrophy in COPD.
ObjectiveTo summarize the autophagy and its research progress in gastric cancer. MethodsIn combination with available literatures published in recent years involving the relationship between autophagy and gastric cancer, the characteristics of autophagy, molecular marker, control factors, and the significance and role in gastric cancer were reviewed. ResultsAutophagy not only promotes cell death, but also can prolong the survival of cancer cells during the tumor formation. Reagents (including traditional Chinese medicine) regulating autophagy have broad prospect of application in cancer therapy, but anti-tumor therapeutic effect based on the regulation of autophagy depends on the actual level of intracellular autophagy. ConclusionThe autophagy in the gastric cancer is still poorly understood, and to clarify the molecular mechanism of autophagy and kill cancer cells by reasonable regulation of autophagy still needs more further in-depth studies.
ObjectiveTo summarize the latest research progress of autophagy on regulation of tumor energy metabolism. MethodThe latest research progresses of the regulation mechanism of autophagy on the energy metabolism of tumor cells and the influence on the biologic behavior of tumor in recent years were reviewed. ResultThe autophagy could affect the biological behavior of the tumor by influence of the tumor cell glucose uptake, glycolysis, oxidative phosphorylation, lipid metabolism, and amino acid metabolism. ConclusionsThe regulation of autophagy on tumor energy metabolism provides a theoretical basis for the survival mechanism of tumor under the stress condition. What's more, to research the mechanism of autophagy on regulation of energy metabolism and the effect on tumor biologic behavior will contribute to the development of new and more effective personalized anticancer therapy. As far as the research progress about tumor cells energy metabolism regulated by autophagy, what we must be revealed is whether other factors including oncogene, anti-oncogene, and signaling pathways take part in this regulation and what influence would be on the biological behavior of different tumors.
ObjectiveTo investigate the changes of autophage-related protein in lung tissues of rats with chronic obstructive pulmonary disease (COPD). MethodsPassive cigarette smoking was used to establish COPD model in rats. The mRNA and protein expressions of PI3K, total AKT, phosphorylated-AKT, total mTOR, phosphorylated-mTOR, and autophagy-related genes including LC3Ⅱ/Ⅰ, Beclin1, Atg5, Atg7, Atg12, P62 in lung tissues were measured by real-time PCR and Western blot. The autophagy level was compared between the COPD rats and the normal rats by LC3B immunohistochemistry. ResultsReal-time PCR analysis showed that the mRNA expressions of Beclin1, Atg5 and Atg12 significantly increased in lung tissues of the COPD rats compared with the normal rats (all P < 05). There was no significant difference between the COPD rats and the normal rats as for Atg7 mRNA expression (P > 0.05). Western blot analysis showed that the protein expressions of PI3K, p-AKT/AKT and p-mTOR/mTOR significantly decreased, the protein expressions of LC3 Ⅱ/Ⅰ, Atg5, and Beclin1 increased, and protein expression of P62 significantly decreased in lung tissues of the COPD rats compared with the normal rats (all P < 05). LC3B immunohistochemistry showed that the LC3B expression was higher in the COPD rats than that in the normal rats. ConclusionThe level of autophagy significantly increases in COPD rats with decreased expression of upstream proteins in autophagy signal pathway and increased expression of autophage proteins.
The neuroretinal injuries of diabetic retinopathy (DR) include retinal neuronal damage and reactive gliosis, both of which are induced by hyperglycemia and presented as early features of DR. They promote to develop mutually and accelerate the progression of DR. The molecular mechanisms study of neuronal damage mainly focuses on the alterations of extracellular environment and related signaling pathways, include inflammation, oxidative stress, endoplasmic reticulum stress, the formation of advanced glycation end products, glutamate toxicity and so on. These alterations mainly result in neuronal apoptosis and autophagy. The damaged neurons activate the glial cells with apparent changes in morphology, cell counts and the level of intracellular protein expression. In non-proliferative DR, glial cells are moderately hypertrophic and slightly increased in numbers. In proliferative DR, there is a significant rise in glial cell number with enhanced level of inflammatory factors and vascular active substances which lead a further neuronal damage. Signaling pathways of extracellular signal-regulated kinase 1/2, c-Fos and p38 mitogen-activated protein kinase are associated with their activation. Researches on the molecular mechanisms and signaling pathways of the DR will promote controlling the DR progression at the cellular level.
ObjectiveThe abnormal autophagy fluxis involved in the pathophysiological process of drug-resistance temporal lobe epilepsy (TLE).Hippocampal sclerosis (HS) is the main pathological type of drug-resistance TLE.Different subtypes of HS have various prognosis, etiology and pathophysiology.However, whether theabnormal block ofautophagy flux involved in this process has not been reported.This study proposed a preliminary comparison of autophagy fluxin typical and atypical HS to investigate the potential pathogenesis and drug-resistance mechanism of atypical HS. MethodsSurgical excision of hippocampal and temporal lobe epilepsy foci were performed in 17 patients with drug-resistance TLE.Patients were grouped according to the HS classification issued by International League Against Epilepsy in 2013.The distribution and expression of LC3B, beclin-1 and P62 were detected by immunohistochemistry and Western blot in each group. ResultsLC3B, beclin-1 and P62 are mainly expressed in neuronal cytoplasm, which is consistent with previous reports.Taking β-actin as internal reference, we found that LC3B and Beclin-1, the downstream products of autophagy flux, have increased significantly (P < 0.01) in the atypical HS group compared to typical HS group.However, the autophagy flux substrate P62 has no difference between the groups.This result suggested that compared with the typical HS group, atypical HS group had autophagy substrate accumulation and autophagy flux abnormal block.Besides, we found that glyceraldehycle-3-phosphate dehydrogenase(GAPDH) was significantly different between the two groups (P=0.003). ConclusionThere is abnormal phenomenon of autophagy flux in atypical HS, and GAPDH elevation may be involved in its mechanism, which might provide new targets and ideas for future treatment of atypical HS.
Age-related macular degeneration is one of the major causes of blindness in the elderly. As an important pathway of cell metabolism, autophagy maintains intracellular homeostasis through the degradation and recycle of damaged organelles and macromolecules. Understanding its mechanism may promote discoveries to delay aging process, reduce the incidence of age-related diseases. In mammals, silent information regulator protein 6 (SIRT6) plays its deacetylase and ribonucleotransferase activity in multiple signaling pathways, including inhibition of cellular senescence, tumorigenesis, metabolic diseases, regulating cellular lifespan. It has a significant impact on the structure and function of tissues and organs. SIRT6 regulates intracellular autophagy mainly through the insulin-like growth factor-protein kinase B-mammalian target of rapamycin, reducing the accumulation of toxic metabolites and cellular senescence. The function of SIRT6 in age-related macular degeneration need to be combined with the genetic background, pathogenesis, clinical manifestations and other aspects of the disease, and it is expected to be further studied in subsequent studies.
ObjectiveTo explore the effect of fingolimod (FTY720) on secondary nerve injury after thalamic-ventricle hemorrhage (TH-IVH) in rats.MethodsAdult male Sprague Dawley rats (clean animal) were randomly divided into 3 groups: sham group, TH-IVH group, and intervention group (FTY720 group), with 6 rats in each group. TH-IVH model was established in both TH-IVH group and FTY720 group, but only the rats in FTY720 group were treated with FTY720. The observation was conducted at the 1st, 3rd and 7th day after modeling. The main observation index included scores of neurological function, change of body weight, water content of brain tissue, the activation of inflammatory cells, the degree of neuronal degeneration and apoptosis, and the level of cell autophagy.ResultsAt the 1st, 3rd and 7th day after modeling, the change of body weight, the neurological score, brain edema and microglia activation in TH-IVH group were statistically different from those in sham group and FTY720 group (P<0.05). The number of degenerated neurons and the number of apoptotic cells in TH-IVH group were statistically different from those in sham group and FTY720 group at the 1st and 3rd day after modeling (P<0.05). The differences in the ratio of LC3Ⅱ/LC3Ⅰ protein expression andBcl-2/Bax expression were statistically significant between FTY720 group and TH-IVH group at the 1st and 3rd day after modeling (P<0.05).ConclusionsFTY720 can improve neurological function of the TH-IVH model in the acute phase, and has certain neuroprotective effect. The neuroprotective effect of FTY720 may be associated with neuronal autophagy and apoptosis regulation and immunosuppression.