mRNA Expression Levels Of Beclin-1 Research Articles

Acetylated Oligopeptide and N-acetyl cysteine Protected Against Oxidative Stress, Inflammation, Testicular-Blood Barrier Damage, and Testicular Cell Death in Iron-Overload Rat Model.

Multiple organs, including the testes, are damaged by iron overload. It has been shown that N-acetyl cysteine (NAC) influences oxidative stress in iron overload. The present study aimed to evaluate the roles of acetylated peptide (AOP) and NAC in the inhibition of iron-overload induced-testicular damage. At the beginning of the experiment, NAC (150 mg /kg) was given for a week to all 40 rats. Then, four groups were formed by dividing the animals (10 rats/group). Group I included healthy control rats. Group II (iron overload) was given intraperitoneal iron dextran (60 mg/kg/day) 5 days a week for 4 weeks. Group III (NAC) was given NAC orally at a dose of 150 mg/kg/day for 4 weeks in addition to iron dextran. Group IV (AOP) was given AOP orally at a dose of 150 mg/kg/day for 4 weeks besides iron dextran. When the experiment time was over, testosterone serum level, testicular B cell lymphoma-2 (BCL-2) and protein kinase B (PKB) protein levels, nuclear factor kappa-B (NF-κB), and Beclin1 mRNA expression levels, and malondialdehyde (MDA), and reduced glutathione (GSH) were determined by ELISA, quantitative reverse transcription-PCR, and chemical methods. Finally, histopathological examinations and immunohistochemical detection of claudin-1 and CD68 were performed. The iron overload group exhibited decreased testosterone, BCL-2, PKB, claudin-1, and GSH and increased MDA, NF-κB, Beclin1, and CD68, while both NAC and AOP treatments protected against the biochemical and histopathological disturbances occurring in the iron overload model. We concluded that NAC and AOP can protect against testes damage by iron overload via their antioxidant, anti-inflammatory, antiapoptotic, and ant-autophagic properties. The NAC and AOP may be used as preventative measures against iron overload-induced testicular damage.

Expression and significance of microtubule associated protein 1 light chain 3B, p62 and Beclin1 in lesion tissues of oral lichen planus patients

Objective: To explore the expression of autophagy related factors microtubule associated protein 1 light chain 3B (LC3B), p62, autophagy key factor Beclin1 in oral lichen planus (OLP) tissues and their relationships with the clinicopathological characteristics of OLP, investigating the function and significance of autophagy in pathogenesis of OLP. Methods: Forty-one lesion tissues (OLP group, twenty-one cases of erosive OLP and twenty cases of non-erosive OLP) were selected from OLP patients visiting the Department of Periodontal and Oral Medicine, School and Hospital of Stomatology, Guizhou Medical University from October 2017 to December 2019. Fifteen cases of normal oral mucosal tissues (control group) were collected from oral and maxillofacial surgery at The Affiliated Stomatology Hospital of Guizhou Medical University during the same period. Protein and mRNA expression levels of LC3B, p62 and Beclin1 were detected by immunohistochemistry (IHC) and real-time quantitative PCR (RT-qPCR) in OLP lesions respectively. The protein expression levels of LC3B, p62, Beclin1 and ratio of LC3B-Ⅱ/LC3B-Ⅰ in sixteen cases (eight cases of erosive OLP and eight cases of non-erosive OLP) from the OLP group were detected by Western blotting (WB). The potential relationship between LC3B, p62, Beclin1, LC3B-Ⅱ/LC3B-Ⅰ ratio and clinical features of OLP were analyzed. Results: IHC results showed that the positive expression rates of LC3B and p62 proteins in OLP lesion tissues [LC3B: 68% (28/41); p62: 59% (24/41)] were higher than those in the control group [LC3B: 5/15; p62: 3/15] (LC3B: χ2=5.55, P=0.019; p62: χ2=5.55, P=0.015). The positive expression rates of LC3B and p62 proteins in the erosive OLP group [LC3B: 86% (18/21); p62: 76% (16/21)] were higher than those in the non-erosive OLP group [LC3B: 50% (10/20); p62: 40% (8/20)] (LC3B: χ2=4.50, P=0.034; p62:χ2=5.53, P=0.019). The positive expression rate of Beclin1 protein in the OLP lesions[20% (8/41)] was lower than that in the control group (7/15) (χ2=4.13, P=0.042), but was not statistically different between the two types of OLP (P>0.05). The RT-qPCR results showed that the mRNA expression levels of LC3B and p62 in OLP lesions [LC3B: 2.78 (1.59, 6.15); p62: 4.30 (2.34, 6.29)] were higher than those in the control group [LC3B: 1.05 (0.88, 1.21); p62: 1.12 (0.89, 1.36)] (LC3B: Z=-4.56, P<0.001; p62: Z=-4.78, P<0.001), and the mRNA expression levels of LC3B and p62 in the erosive OLP group were higher than those in the non-erosive OLP group (LC3B: Z=-2.87, P=0.004; p62: Z=-2.95, P=0.003). The mRNA expression level of Beclin1 in OLP tissues was lower than that in the control group (Z=-2.43, P=0.015), but the difference was not statistically significant between the two types of OLP (P>0.05). WB results showed that the LC3B-Ⅱ/LC3B-Ⅰ ratio was higher in the OLP lesions than that in the control group (t=-2.45, P=0.021), and the LC3B-Ⅱ/LC3B-Ⅰ ratio was higher in the non-erosive OLP group than in the erosive OLP group (t=-2.38, P=0.032). Spearman's correlation analysis showed that the ratio was negatively correlated with the clinical staging and the degree of basal cell liquefaction in OLP (clinical staging: r=-0.57, P=0.021; basal cell liquefaction: r=-0.54, P=0.032), but not with the disease duration and the degree of lymphocytic infiltration (P>0.05). Conclusions: Autophagy related factors LC3B, p62 and Beclin1 may play a role in the formation and progression of OLP lesions. The autophagy level was relatively lack in erosive OLP compared to non-erosive OLP, contributing to the increased local lesion destruction in erosive OLP. Abnormal cellular autophagy may play an important role in the formation of OLP lesions.

Selenium ameliorates inflammation by decreasing autophagic flux and mitogen-activated protein kinase signalling on experimentally induced rat periapical lesions.

To reveal the molecular mechanisms that targets mitogen-activated protein kinase (MAPK) signalling and the autophagic flux and to investigate the possible effects of the systemic administration of selenium (Se) on experimentally induced rat periapical lesions. Thirty adult Sprague-Dawley rats were divided equally into negative control, positive control and Se groups. In the positive control and Se groups, the pulp chambers of their mandibular first molars were exposed to the oral environment to induce periapical lesions The Se group received daily intraperitoneal injections of Se at a dose of 0.1mg kg-1 . After 28 days, the amount of bone destruction; severity of inflammation; penetration of microorganisms along the root canal; collagen degradation in periodontal ligament; interleukin (IL)-6, hypoxia-inducible factor-1 (HIF-1), cyclooxygenase-2 (COX-2) and caspase-3 expression; autophagic flux; and p38 MAPK signalling were evaluated using radiographic, histopathological, Gram staining, picrosirius red stain, immunohistochemical, quantitative real-time polymerase chain (qRT-PCR) and Western blot methods, respectively. These data were analysed through the Kruskal-Wallis and Dunnett's tests (p < .05). The area of radiographic periapical bone loss, histopathological scores, the area of periapical bone loss and the scores for the bacteria localisation, the intensity of immunohistochemical staining for IL-6, HIF-1, COX-2 and caspase-3 in the Se group was significantly less than those of the positive control group (p < .01). The mRNA expression levels of Beclin-1, Atg3, Atg5, Atg7 and Atg16L1 were lower in the Se group than in the positive control group (p < .01). The protein expressions of Beclin-1, Atg5 and LC3-II, the phosphorylation ratio of the p38 MAPK and the ratios of LC3II/LC3I were significantly higher (p < .05) in the positive control and Se groups. On the contrary, the expression of the p62/SQSTM1 protein was significantly lower (p < .05) in the positive control and Se groups than in the negative control group. The induction of periapical lesions in rats increased autophagic flux and activated p38 MAPK signal transduction processes. Se suppressed the inflammatory process, reduced bone destruction and both the autophagic flux and p38 MAPK activation.

Methylprednisolone Inhibits Autophagy of Vascular Endothelial Cells in Rat Femoral Head ViaPI3K/Akt/mTOR Pathway

ObjectiveTo study the relationship between vascular endothelial cells (VEC) and autophagy, and its regulatory mechanism in steroid‐induced avascular necrosis of the femoral head (SANFH).MethodsIn cell experiment, VEC were isolated and cultured from the femoral head of Sprague–Dawley rats and divided into three groups: blank control group (Ctrl), methylprednisolone group (MP), and methylprednisolone+mTOR‐shRNA group (MP + shmTOR). The autophagy formation was observed by transmission electron microscope. The mRNA expression of PI3K, Akt, mTOR, Beclin1 and MAP1LC3 was detected by RT‐PCR and the protein expression was detected by Western blot and immunofluorescence. Expression of the damage marker 6‐keto‐PGF1α was detected by the ELISA method. In vivo experiment, after establishing the model, the grouping method was the same as cell experiment. Autophagosomes were observed by same method, and the expression of related factors was detected by the same method in cell experiment.ResultsIn the cell experiment, autophagosomes in the MP group were significantly lower than in the Ctrl group, and the autophagosomes in the MP + shmTOR group were intermediate between two groups (P < 0.05). The mRNA expression levels of PI3K, Akt and mTOR in the MP group were significantly higher than in the Ctrl group, while the MP+ shmTOR group presented intermediate levels between these groups (average gray value were 3837.90, 2996.30, 3005.60, F = 428.64, P < 0.05). MRNA expression levels of Beclin1 and MAP1LC3 in the MP group were significantly lower than that in Ctrl group (P < 0.05). The content of 6‐keto‐PGF1α in the MP + shmTOR group was higher than in the Ctrl group and lower than in the MP group at the evaluated time intervals (average absorbance value were 104.98, 206.83, 145.91, F = 352.83, P < 0.01). In vivo experiment, the content of 6‐Keto‐PGF1α in the hormone group increased as time went on; the mTOR‐si group was higher than that in control group, but lower than that in the hormone group (P < 0.01). The mRNA expressions of Beclin1 and MAP1LC3 in the control group were higher than those in the hormone group, while the mRNA expressions of PI3K, Akt and mTOR were lower than those in the mTOR‐si group (P < 0.05).ConclusionThe steroid inhibited the physiological protective effect of autophagy on SANFH by increasing the expression of PI3K/Akt/mTOR signaling pathway related factors and decreasing the expression of Beclin1 and MAP1LC3 in the femoral head VEC.

Heat stress in broilers of liver injury effects of heat stress on oxidative stress and autophagy in liver of broilers

This study aimed to investigate the effect of chronic heat stress on oxidative stress in liver of broilers. In our study, chickens were randomly allocated to control 1 group (control 7 d), heat stress 1 group (HS1, 7 d), control 2 group (control 14 d) and heat stress 2 group (HS2, 14 d), with 30 replicates in each group. Broilers in heat stress groups exposed 8 h/day heat stress (35 ± 2°C) for 7 or 14 consecutive days, and the rest of time per day were kept at 23 ± 2℃ the same as control group broilers. Growth performance and the liver tissues were collected for histological observation and detection of organ index and liver redox status. The serum indicators (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) related to liver injury were determined. Moreover, Nrf2-related genes and protein expression levels in liver were measured. The results showed that in heat stress group broilers the body weight gain, feed conversion ratio, liver weight, and liver index were decreased, inflammatory cells infiltration in liver, and serum AST level was enhanced, compared with control group broilers. Moreover, the hepatic malondialdehyde (MDA) and superoxide dismutase (SOD) level were increased after 1 wk of heat stress. Nrf2, Sqstm1/p62, HO-1, and NQO1 mRNA expressions in the liver of broilers were decreased by heat stress. P62 and p-p62 protein expressions were significantly up-regulated, but Nrf2 and keap1 protein level was decreased in heat stress group broilers as compared to control group. The mRNA expression levels of Beclin1, LC3-I, LC3-II were down-regulated significantly with heat stress for 1 wk. The mRNA expression level of mTOR up-regulated after 2 wk of heat stress. In conclusion, heat stress induced liver injury of broilers by down-regulating Nrf2-keap1 signaling pathway and autophagy.

Upregulation of necroptosis markers RIPK3/MLKL and their crosstalk with autophagy-related protein Beclin-1 in primary immune thrombocytopenia

Necroptosis is a novel form of programmed necrotic cell death involved in various autoimmune diseases. The potential role of necroptosis in primary immune thrombocytopenia (ITP) and the possible interlink with autophagy have not been fully investigated. The gene expression of mixed lineage kinase-like domain (MLKL), receptor-interacting protein kinase 3 (RIPK3) and Beclin-1 were quantified in peripheral blood of 45 ITP patients and 20 healthy controls. Their associations with clinical, laboratory parameters and response to steroid therapy in ITP patients were evaluated. RIPK3, MLKL, and Beclin-1 were significantly upregulated in ITP patients than in healthy controls (P < 0.001). Beclin-1 mRNA levels were positively correlated with both RIPK3 and MLKL mRNA levels in ITP patients (P < 0.0001). In addition, MLKL, RIPK3, and Beclin-1 mRNA levels were inversely correlated with platelet count (r = −0.330, −0.527 and −0.608, respectively). On the hand, positive correlations between MLKL (P = 0.01), RIPK3 (P = 0.005), Beclin-1 (P = 0.002) mRNA levels and severity of bleeding in ITP patients were reported. Steroid responders (n = 18, 40%) had significantly lower MLKL, RIPK3, Beclin-1 mRNA expression levels than their levels in the non-responders (n = 27, 60%). Necroptosis may play a critical role in the pathogenesis of ITP and provide both novel therapeutic targets and promising biomarkers for the prediction of bleeding severity and treatment response in ITP patients. Additionally, this study highlighted the crosstalk between autophagy and necroptosis in ITP patients.Graphical abstract

Effects of electroacupuncture on autophagy factors and liver lipid metabolism in rapidly aging mice

Objective: To study the effects of electroacupuncture on the expressions of autophagy-related factors LC3-Ⅱ, Beclin1, Atg7, and P62 in the liver of rapidly aging (senescence accelerated mouse/prone8,SAMP8) mice, and to explore the mechanisms of electroacupuncture to improve liver lipid metabolism in mice. Methods: Thirty-week-old male SAMP8 mice were randomly divided into model group, drug group, and electroacupuncture group, with 7 mice in each group. Seven anti-rapid aging SAMR1 mice of the same age were used as the control group. The animals in the control group and the model group were bred routinely for 2 weeks without any intervention; the drug group was treated with intraperitoneal injection of rapamycin at the dose of 10 mg·kg-1·d-1, once a day, 6 consecutive days a week; the electroacupuncture group was given "Shenshu" and "Taichong" Electroacupuncture at point(15 minutes a day, 6 consecutive days a week). The serum lipid metabolism and liver lipid deposition of mice were detected, the distribution of liver autophagy body, the protein and mRNA expressions of liver LC3 - Ⅱ, Beclin1, Atg7 and P62 were determined. Results: Compared with the control group, the total cholesterol (TC), triglycerides (TG), and low density lipoprotein (LDL) of the model group were increased significantly(P＜0.01). In the model group, lipid droplet deposition was obvious, autophagosomes were decreased, the protein and mRNA expression levels of autophagy- related factors LC3-Ⅱ, Beclin1 and Atg7 were decreased significantly (P＜0.01), while the protein and mRNA expressions of P62 were increased significantly (P＜0.01). Compared with the model group, the serum contents of TG, TC, and LDL of the mice in the electroacupuncture group and the drug group were decreased significantly (P＜0.01), lipid droplet deposition was reduced, autophagosomes were increased, the protein and mRNA expression levels of LC3 -Ⅱ, Beclin1 and Atg7 were increased significantly(P＜0.01), and the protein and mRNA expression levels of P62 were decreased significantly(P＜0.01). The protein and mRNA expression levels of Beclin1 and Atg7 in the liver of the electroacupuncture group were not significantly different from the drug group (P＞0.05). Conclusion: Electroacupuncture can alleviate liver lipid metabolism disorders, which may be related to the regulation of the expressions of liver autophagy related factors LC3-Ⅱ, Beclin1, Atg7, and P62, thereby promoting liver autophagy in SAMP8 mice.

Abnormal expression of autophagy-related proteins in immune thrombocytopenia.

Autophagy is a highly conserved protein degradation pathway that is essential for affecting some autoimmune diseases. Immune thrombocytopenia (ITP) is a common autoimmune disorder, and the complex dysregulation of cellular immunity has been observed; however, the relationship between autophagy-related proteins and immune responses in ITP remains unclear. Using real-time quantitative polymerase chain reaction (RT-PCR), the mRNA expression levels of Beclin-1, SQSTM1/p62 and LC3 were measured in the peripheral blood mononuclear cells (PBMCs) of 20 newly diagnosed patients with active ITP, 16 ITP patients in remission and 21 healthy volunteers. The stained Beclin-1 and SQSTM1/p62 proteins were also observed in the bone marrow of active ITP patients and normal controls by immunofluorescence. SQSTM1/p62 mRNA expression in PBMCs in newly diagnosed patients was significantly decreased. At the same time, Beclin-1 mRNA was increased significantly. During the remission stages, the levels of these autophagy-related proteins were comparable with those observed in healthy controls. Taken together, these results suggest that the aberrant expression of autophagy-related proteins might be involved in the pathogenesis of ITP. Further study of the autophagy pathway may provide a new strategy and direction for the treatment of ITP.

Protective Effects of Curcumin Against Paclitaxel-Induced Spinal Cord and Sciatic Nerve Injuries in Rats.

Paclitaxel (PTX) is an antineoplastic agent commonly used in the treatment of solid tumors and is known to cause dose-limiting peripheral neurotoxicity. This study was performed to evaluate the protective effect of curcumin (CUR) against PTX-induced spinal cord and sciatic nerve injuries in rats. The rats were administered PTX (2mg/kg, BW) intraperitoneally for the first 5 consecutive days followed by administration of CUR (100 and 200mg/kg, BW daily in corn oil) orally for 10days. Our results showed that CUR significantly reduced mRNA expression levels of NF-κB, TNF-α, IL-6, iNOS and GFAP whereas caused an increase in levels of Nrf2, HO-1 and NQO1 in the spinal cord and sciatic nerve of PTX-induced rats. In addition, CUR suppressed the activation of apoptotic and autophagic pathways by increasing Bcl-2 and Bcl-xL, and decreasing p53, caspase-3, Apaf-1, LC3A, LC3B and beclin-1 mRNA expression levels. The results showed that CUR also maintained the spinal cord and sciatic nerve histological architecture and integrity by both LFB staining and H&E staining. Immunohistochemical expressions of 8-OHdG, caspase-3 and LC3B in the PTX-induced spinal cord tissue were decreased after administration of CUR. Taken together, our findings demonstrated that CUR has protective effects on PTX-induced spinal cord and sciatic nerve injuries in rats.

Effects of copper on oxidative stress and autophagy in hypothalamus of broilers

The purpose of this research was to discuss the effects of copper (Cu)-induced toxicity on oxidative stress and autophagy in hypothalamus of broilers. In this study, 240 one-day-old broilers were randomly divided into 4 groups and the contents of dietary Cu in 4 groups were 11 mg/kg (control group), 110 mg/kg (group I), 220 mg/kg (group II), and 330 mg/kg (group III). The experiment lasted for 49 days and the hypothalamus tissues were collected for histological observation and detection of Cu content. Additionally, the indicators related to oxidative stress in hypothalamus were determined. Moreover, the mRNA expression levels of autophagy-related genes and the protein expression levels of Beclin1, LC3-II/LC3-I, and p62 in hypothalamus were measured. Results showed that the treated groups were observed vacuolar degeneration in hypothalamus compared to control group, and the Cu content in hypothalamus was increased with the increase of dietary Cu. Furthermore, the activities of SOD, CAT, T-AOC were increased in group I and group II and then decreased in group III, and the content of MDA and the mRNA levels of Nrf2, HO-1, SOD-1, CAT, GCLC, GCLM, and GST in treated groups were elevated compared to control group. Moreover, the mRNA expression levels of Beclin1, Atg5, LC3-I, LC3-II and the protein expression levels of Beclin1 and LC3-II/LC3-I up-regulated significantly with the increasing levels of Cu. However, the mRNA expression levels of p62 and mTOR and the protein expression level of p62 down-regulated remarkably. Taken together, our present study evidenced that excessive intake of Cu could induce oxidative stress and autophagy in hypothalamus of broilers.

Overexpression of let-7a increases neurotoxicity in a PC12 cell model of Alzheimer's disease via regulating autophagy.

Increased deposition of β-amyloid (Aβ) protein is one of the typical characteristics of Alzheimer's disease (AD). Recent evidence has demonstrated that the microRNA let-7 family, which is highly expressed in the central nervous system, participates in the regulation of pathologic processes of AD. In the present study, the effect of let-7a overexpression on Aβ1-40-induced neurotoxicity was evaluated in PC12 and SK-N-SH cells. The results indicated that overexpression of let-7a enhanced the neurotoxicity induced by Aβ1-40 in PC12 and SK-N-SH cells. In addition, the apoptosis induced by Aβ1-40 in PC12 and SK-N-SH cells was increased by let-7a overexpression. Furthermore, Aβ1-40 treatment increased the protein levels of microtubule-associated protein 1A/1B-light chain 3 (LC3) and beclin-1 and increased the LC3 II/I ratio. The mRNA expression levels of beclin-1, autophagy protein 5 (Atg-5) and Atg-7 were also increased by Aβ1-40 treatment in PC12 cells. Let-7a overexpression further upregulated the above autophagy-related markers. Furthermore, the protein level of p62 was increased by Aβ1-40 treatment, and this was further enhanced by let-7a overexpression. Finally, the present results demonstrated that the phosphoinositide-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway was involved in the autophagy regulation by let-7a. In conclusion, the present study demonstrates that the neurotoxicity induced by Aβ1-40 is augmented by let-7a overexpression via regulation of autophagy, and the PI3K/Akt/mTOR signaling pathway also serves a function in this process.

Starvation-induced changes of LC-3 and Beclin-1 expression in annulus fibrosus cells

Objective To investigate the starvation-induced changes of LC-3 and Beclin-1 expression in annulus fibrosus cells. Methods Rat annulus fibrosus cells in the logarithmic growth phase were cultured with amino acid free EBSS (Earle' s balanced salt) medium instead of the DMEM-F12 medium.Cells were collected at 1, 2 and 3 h after EBSS culture. Autopagosomes in annulus fibrosus cells were detected with monodansylcadaverine ( MDC) fluorescent staining method. Reverse transcription-polymerase chain reaction ( RT-PCR) and Western blotting analyses were used to detect the expression of microtubuleassociated protein 1 light chain 3 (LC3 ) and Beclin-1 in annulus fibrosus cells. Results Compared with the control group, MDC positive cells and autopagosomes were increased with the prolongation of starvation.LC3-Ⅱ and Beclin-1 mRNA expression levels in annulus fibrosus cells were increased with the prolongation of starvation (LC3-Ⅱ : 0.21 ±0.02, 0.45 +0. 12, 0.60±0.05, 0. 74 ±0. 03,P＜0. 05; Beclin-1: 0.20 ±0.06, 0. 37 ±0. 11, 0.52 ±0.07, 0. 69 ±0. 07,P＜0. 05). The ratio of LC3-Ⅱ/LC3-Ⅰ and Beclin-1 protein expression was also increased with the prolongation of starvation (LC3-Ⅱ/LC3- Ⅰ : 0. 12 ±0.05,0.32 ±0.09, 0.63 ±0.07, 0. 92 ±0. 04,P＜0.05; Beclin-1: 0.61 ±0. 10, 0. 83 ±0. 11, 1.09 ±0.05,1. 35 ± 0. 10, P ＜ 0. 05 ). Conclusion Autophagy of annulus fibrosus cells can be induced by starvation,which may be related to the procession of intervertebral disc degeneration. Key words: Intervertebral disc degeneration; Annulus fibrosus cell; Autophagy

Autophagy Is Activated by TGF-β and Potentiates TGF-β–Mediated Growth Inhibition in Human Hepatocellular Carcinoma Cells

Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that regulates cell growth, differentiation, and apoptosis of various types of cells. Autophagy is emerging as a critical response of normal and cancer cells to environmental changes, but the relationship between TGF-beta signaling and autophagy has been poorly understood. Here, we showed that TGF-beta activates autophagy in human hepatocellular carcinoma cell lines. TGF-beta induced accumulation of autophagosomes and conversion of microtubule-associated protein 1 light chain 3 and enhanced the degradation rate of long-lived proteins. TGF-beta increased the mRNA expression levels of BECLIN1, ATG5, ATG7, and death-associated protein kinase (DAPK). Knockdown of Smad2/3, Smad4, or DAPK, or inhibition of c-Jun NH(2)-terminal kinase, attenuated TGF-beta-induced autophagy, indicating the involvement of both Smad and non-Smad pathway(s). TGF-beta activated autophagy earlier than execution of apoptosis (6-12 versus 48 h), and reduction of autophagy genes by small interfering RNA attenuated TGF-beta-mediated growth inhibition and induction of proapoptotic genes Bim and Bmf, suggesting the contribution of autophagy pathway to the growth-inhibitory effect of TGF-beta. Additionally, TGF-beta also induced autophagy in some mammary carcinoma cells, including MDA-MB-231 cells. These findings show that TGF-beta signaling pathway activates autophagy in certain human cancer cells and that induction of autophagy is a novel aspect of biological functions of TGF-beta.