scholarly journals Plasmodium circumsporozoite protein enhances the efficacy of gefitinib in lung adenocarcinoma cells by inhibiting autophagy via proteasomal degradation of LC3B

2021 ◽  
Author(s):  
Xiao Lu ◽  
Jiao Zhang ◽  
Quanxing Liu ◽  
Dong Zhou ◽  
Xufeng Deng ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Cell Viability ◽  
Nude Mice ◽  
Specific Inhibitor ◽  
Proteasomal Degradation ◽  
Circumsporozoite Protein ◽  
Control Group ◽  
Egfr Tkis

Abstract Background: Almost all patients with lung adenocarcinoma (LUAD) develop resistance to EGFR-TKIs, which limit the long-term clinical application of these agents. Accumulating evidence shows one of the main reasons for resistance to EGFR-TKIs is induction of autophagy in tumor cells. Our previous study found that circumsporozoite protein (CSP) in Plasmodium can suppress autophagy in host hepatocytes. However, it is unknown whether CSP-mediated inhibition of autophagy could improve the anti-tumor effect of EGFR-TKIs. Methods: We constructed A549 and H1975 cell lines with stable overexpression of CSP (OE-CSP cells). CCK-8, LDH, flow cytometry, and colony analysis were performed to observe the effect of CSP overexpression on cell viability, the apoptosis rate, and stemness. The sensitizing effect of CSP on gefitinib was evaluated in vivo using a subcutaneous tumor model in nude mice and immunohistochemical assay. The role of CSP in regulation of autophagy was investigated by laser confocal microscopy assay and Western blotting. A transcriptome sequencing assay and real-time polymerase chain reaction were used to determine the levels of mRNA for autophagy-related proteins. Cyclohexane, MG132, TAK-243, and immunoprecipitation assays were used to detect and confirm proteasomal degradation of LC3B. Results: OE-CSP A549 and H1975 cells were more sensitive to gefitinib, demonstrating significant amounts of apoptosis and decreased viability. In the OE-CSP group, autophagy was significantly inhibited, and there was a decrease in LC3B protein after exposure to gefitinib. Cell viability and stemness were recovered when OE-CSP cells were exposed to rapamycin. In nude mice with xenografts of LUAD cells, inhibition of autophagy by CSP resulted in suppression of cell growth and more marked apoptosis during exposure to gefitinib. CSP promoted ubiquitin-proteasome degradation of LC3B, leading to inhibition of autophagy in LUAD cells after treatment with gefitinib . When LUAD cells were treated with the ubiquitin-specific inhibitor TAK-243, cell viability, apoptosis, and growth were comparable between the OE-CSP group and a control group both in vivo and in vitro . Conclusions: CSP can inhibit gefitinib-induced autophagy via proteasomal degradation of LC3B, which suggests that CSP could be used as an autophagy inhibitor to sensitize EGFR-TKIs.

scholarly journals Ezh2 Inhibitors Reverse Resistance to Gefitinib in Primary Egfr Wild-type Lung Cancer Cells

2020 ◽  
Author(s):  
Hao Gong ◽  
Yongwen Li ◽  
Yin Yuan ◽  
Weiting Li ◽  
Hongbing Zhang ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Lung Adenocarcinoma ◽  
Cell Viability ◽  
Lung Squamous Cell Carcinoma ◽  
The Cancer Genome Atlas ◽  
Egfr Mutations ◽  
Wild Type ◽  
Egfr Tkis

Abstract Background: Lung cancer is the leading cause of cancer-related death worldwide. Non–small-cell lung cancer (NSCLC) is the most common type of lung cancer. Traditional anticancer therapies involving epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (EGFR-TKIs) have been proven beneficial in the treatment of patients with EGFR mutations. However, patients with EGFR wild-type NSCLC usually fail to respond to EGFR-TKIs. Enhancer of zeste homolog 2 (EZH2), a key molecule of the PRC2 complex, plays an important role in epigenetic regulation and is overexpressed in various tumors. EZH2 inhibitors sensitize various types of tumor cells to antitumor drugs. Therefore, this study aimed to investigate whether the EZH2 inhibitors GSK343 and DZNep, whencombined with gefitinib, can reverse EGFR-TKI resistance in EGFR wild-type NSCLC. Methods:EZH2 expression was evaluated using the RNA sequencing dataset of NSCLC patients (502 lung squamous cell carcinoma cases including 49 paracancerous lung tissues and 513 lung adenocarcinoma cases including 59 paracancerous lung tissues) from The Cancer Genome Atlas (TCGA). We simultaneously also verified EZH2 expressionin 40 NSCLC samples and their corresponding paracancerous lung tissues from our institution via quantitative PCR. The lung adenocarcinoma cell lines A549 and H1299 were treated with EZH2-specific small interfering RNA or EZH2 inhibitors and subjected to analyses of cell viability and apoptosis as well as of EGFR pathway protein expressions by western blotting. Results: EZH2 was upregulated in human NSCLC tissues and was correlated with poor prognosis in patients with lung adenocarcinoma based on data from both TCGA and our institution. Both EZH2 inhibitors sensitized A549 and H1299 cells to gefitinib and suppressed cell viability and proliferation in vitroby downregulating the phosphorylation of EGFR and AKT and inducing cell apoptosis. Co-administration of EZH2 inhibitors (GSK343 or DZNep) with gefitinib exerted stronger inhibitory effects on tumor activity, cell proliferation, and cell migration than single drug administration in vitro and in vivo.Conclusion: Co-administration of EZH2 inhibitors with EGFR-TKIs may be feasible for the treatment of EGFR wild-type NSCLC in patients who refuse traditional chemotherapy.

scholarly journals Exploiting GRK2 Inhibition as a Therapeutic Option in Experimental Cancer Treatment: Role of p53-Induced Mitochondrial Apoptosis

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3530
Author(s):  
Jessica Gambardella ◽  
Antonella Fiordelisi ◽  
Gaetano Santulli ◽  
Michele Ciccarelli ◽  
Federica Andrea Cerasuolo ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cancer Cell ◽  
Nude Mice ◽  
Specific Inhibitor ◽  
Cancer Cell Proliferation ◽  
In Vivo Models ◽  
P53 Expression

The involvement of GRK2 in cancer cell proliferation and its counter-regulation of p53 have been suggested in breast cancer even if the underlying mechanism has not yet been elucidated. Furthermore, the possibility to pharmacologically inhibit GRK2 to delay cancer cell proliferation has never been explored. We investigated this possibility by setting up a study that combined in vitro and in vivo models to underpin the crosstalk between GRK2 and p53. To reach this aim, we took advantage of the different expression of p53 in cell lines of thyroid cancer (BHT 101 expressing p53 and FRO cells, which are p53-null) in which we overexpressed or silenced GRK2. The pharmacological inhibition of GRK2 was achieved using the specific inhibitor KRX-C7. The in vivo study was performed in Balb/c nude mice, where we treated BHT-101 or FRO-derived tumors with KRX-C7. In our in vitro model, FRO cells were unaffected by GRK2 expression levels, whereas BHT-101 cells were sensitive, thus suggesting a role for p53. The regulation of p53 by GRK2 is due to phosphorylative events in Thr-55, which induce the degradation of p53. In BHT-101 cells, the pharmacologic inhibition of GRK2 by KRX-C7 increased p53 levels and activated apoptosis through the mitochondrial release of cytochrome c. These KRX-C7-mediated events were also confirmed in cancer allograft models in nude mice. In conclusion, our data showed that GRK2 counter-regulates p53 expression in cancer cells through a kinase-dependent activity. Our results further corroborate the anti-proliferative role of GRK2 inhibitors in p53-sensitive tumors and propose GRK2 as a therapeutic target in selected cancers.

CNS-9, a Novel Specific Inhibitor of ABL Tyrosine Kinase Overcomes Resistance Mechanism of Imatinib.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 761-761 ◽  
Author(s):  
Shinya Kimura ◽  
Hidekazu Segawa ◽  
Junya Kuroda ◽  
Takeshi Yuasa ◽  
Taira Maekawa
Keyword(s):  
Tyrosine Kinase ◽  
Growth Inhibition ◽  
Cell Lines ◽  
Nude Mice ◽  
Philadelphia Chromosome ◽  
Specific Inhibitor ◽  
Vitro Assay ◽  
Abl Tyrosine Kinase

Abstract Imatinib mesylate (also known as STI-571 and Gleevec) has drastically changed the treatment of Philadelphia chromosome positive (Ph+) leukemias. However, the resistance to imatinib has frequently been reported, particularly in patients with advanced-stage disease. A novel orally bioavailable inhibitor of the ABL tyrosine kinase (TK) named CNS-9 was developed from the 2-(phenylamino)pyrimidine class to overcome resistance mechanisms of imatinib. Inhibition of TK phosphorylation (IC50) on wild type (wt) BCR/ABL in 293T cell line by CNS-9 was 22nM, which was 2-log more potent than imatinib. Importantly, CNS-9 inhibited TK phosphorylation of E255K mutant BCR/ABL with IC50 of 98nM, while imatinib could not inhibit it with clinically relevant concentration. The T315I mutant BCR/ABL protein was resistant to CNS-9 and imatinib. CNS-9 also inhibited TK phosphorylation of platelet-derived growth factor receptor (PDGFR) or c-Kit pathways at the very similar observed IC50s when compared with imatinib, in spite of significant higher potency against ABL. The ability of CNS-9 in vitro to inhibit 101 TK molecules was assayed by KinaseProfilerTM (Upstate), showing also more specific inhibitory activity against ABL than imatinib. The growth of BCR/ABL-positive cell lines K562, KU812, BaF3 harboring wt BCR/ABL (BaF3/wt) and E255K (BaF3/E255K) was inhibited by CNS-9 with IC50 of 5, 3, 17, and 110nM, respectively (Table 1). Generally, CNS-9 was 20 to 30-fold more potent on the growth inhibition than imatinib in these same cell lines. We next investigated the in vivo effect on the leukemic growth inhibition of CNS-9. Nude mice were injected subcutaneously with 3x107 KU812 (wt BCR/ABL) on Day 0. CNS-9 or imatinib were orally administrated twice a day from Day 7 to Day 18. The dosages of CNS-9 and imatinib, which inhibited completely tumor growth were 20mg/kg/day and 200mg/kg/day, respectively, indicating that CNS-9 is 10-fold potent than imatinib in vivo. To examine the in vivo effect of CNS-9 against mutant BCR/ABL, BaF3/wt, BaF3/E255K or BaF3/T315I were engrafted to nude mice and treated with CNS-9 or imatinib. CNS-9 was also 10-fold potent than imatinib against BaF3/wt. Intriguingly, mice harboring BaF3/wt or BaF3/E255K showed significantly prolonged survival when treated with CNS-9. Consistent with in vitro assay, CNS-9 had no effect on T315I, and imatinib was not effective against both E255K and T315I. In conclusion, CNS-9 is substantially more inhibitory and more specifically than imatinib toward BCR/ABL-dependent cell growth both in vitro and in vivo Moreover, CNS-9 may be effective for leukemia patients whose leukemic cells harbor E255K mutant. The efficacy and safety of CNS-9 for Ph+ leukemias should be verified in early phase clinical trials. The IC50s values of leukemic cell lines for CNS-9 and imatinib CNS-9 (nM) imatinib (nM) K562 p210 wt BCR/ABL 5 130 KU812 p210 wt BCR/ABL 3 67 U937 BCR/ABL (−) >1000 >1000 BaF3 p190 wt BCR/ABL 17 360 BaF3 p190 E255K BCR/ABL 110 >1000 BaF3 p190 T315I BCR/ABL >1000 >1000

Evaluation of Anti-Tumor Potential of Lactobacillus acidophilus ATCC4356 Culture Supernatants in MCF-7 Breast Cancer

2020 ◽  
Vol 21 ◽  
Author(s):  
Ramazan Behzadi ◽  
Ahmad Hormati ◽  
Karim Eivaziatashbeik ◽  
Sajjad Ahmadpour ◽  
Fatemeh Khodadust ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Nude Mice ◽  
Control Group ◽  
Bacterial Strains ◽  
Anti Cancer ◽  
99Mtc Mibi ◽  
Culture Supernatants ◽  
Mcf 7

Background: Anti-cancer activity of some lactic acid bacterial strains is well documented in several literatures. Lactobacillus strains have received considerable attention as a beneficial microbiota. The aim of this study is to evaluate the effects of anti-tumor activities of L. acidophilus ATCC4356 culture supernatants on the MCF-7 human breast cancer cells. Materials and methods: Anti-cancer effect of 24h and 48h culture supernatants at various concentrations (1.25, 2.5, 5, 10 and 20 µg/ml) were determined by various in vitro and in vivo assays including MTT, tumor volume measurement as well as 99mTc-MIBI biodistribution in MCF-7 tumor bearing nude mice and histopathology test. For evaluation of the related mechanism of action, quantitative PCR was conducted. Results: The 48h culture supernatants at 10 and 20 µg/ml exhibited significant in vitro inhibition of MCF-7 cell proliferation. However, this inhibition was not observed for HUVEC human endothelial normal cells. Q-PCR indicated that treatment by the supernatant led to a significant downregulation of VEGFR ( ̴ 0.009 fold) and Bcl-2 ( ̴ 0.5 fold) and upregulation of p53 ( ̴ 1.3 fold). In vivo study using MCF-7 xenograft mouse models demonstrated reduction in tumor weight and volume by both 24h and 48h supernatants (10 µg/ml and 20 µg/ml) after 15 days. According to the 99mTc-MIBI biodistribution result, treatment of MCF-7 bearing nude mice with both 24h and 48h supernatant (20 µg/ml) led to significant decrease in tumor uptake compared with the control group. Conclusion: These results suggest that the culture supernatants of L. acidophilus ATCC4356 at suitable concentrations can be considered as a good alternative nutraceutical with promising therapeutic indexes for breast cancer.

Alpha Lipoic Acid (ALA) Inhibits the Anti-Myeloma Effects of Bortezomib.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3832-3832 ◽  
Author(s):  
Jeffrey A Steinberg ◽  
Jing Shen ◽  
Eric Sanchez ◽  
Haiming Chen ◽  
Zhi-Wei Li ◽  
...  
Keyword(s):  
Cell Viability ◽  
Cell Lines ◽  
Vascular Dysfunction ◽  
Single Agent ◽  
Inhibitory Effect ◽  
Control Group ◽  
Treatment Schedule ◽  
20 Nm

Abstract Abstract 3832 Poster Board III-768 Introduction ALA is an antioxidant often used in the management of peripheral neuropathy (PN) for patients with multiple myeloma (MM). A clinical trial evaluating ALA in diabetic neuropathy showed this drug to be effective for patients with both somatic and autonomic neuropathies. It also normalized the endoneural blood flow, reduced oxidative stress and improved vascular dysfunction. Bortezomib (Velcade®), the first-in-class proteasome inhibitor (PI), which is approved for the treatment of patients with MM, may cause PN. As a result, patients are often treated empirically with ALA. In this study, we investigated whether ALA has any impact on the anti-MM effects of bortezomib. Methods First, cells from the MM cell lines RPMI8226 and MM1S (1×105 cells per 100μl) were treated with ALA alone to determine whether ALA had any effects on their growth as determined with an MTS assay. MM cells were plated in a 96-well plate using serum-free media. The cells were treated with either media alone or ALA at concentrations ranging from 1 to 1000 μM for 48 hours. The acidity of ALA at these doses was determined and if the pH was less than 7, we neutralized it using NaOH. Second, we measured the proliferation of cells exposed to bortezomib alone and combinations of a fixed concentration of bortezomib and escalating concentrations of ALA. Results The exposure of cells to ALA alone had a stimulatory effect on the growth of both MM cell lines in vitro. ALA alone at 1000 μM resulted in an increase in cell viability of MM1S cells by approximately 10% when compared to the control group. ALA alone also stimulated the growth of RPMI8226 cells but at much lower concentrations than observed for MM1S. Compared to untreated cells, there was an increase in cell viability with ALA at concentrations as low as 1 μM and a concentration dependent increase at concentrations of 1, 10, 100, and 1000 μM in RPMI8226 cells. At the highest concentration (1000 μM) of ALA, cell viability increased 150% when compared to RPMI8226 cells incubated with media alone. Next, we evaluated the effect of ALA on bortezomib's anti-MM activity. As a single agent, bortezomib reduced MM1S (20 nM) and RPMI8226 (5 nM) cell viability by 93% and 70% respectively. When ALA was added at a clinically achievable concentration (100 μM) to bortezomib (RPMI8226, 5 nM; MM1S, 20 nM), a reduction in the anti-MM effects of bortezomib on these cell lines was observed when compared to bortezomib treatment alone. Compared to bortezomib alone, the combination of ALA plus bortezomib doubled cell viability (increased RPMI8226 and MM1S cell viability from 32.5% to 65% and 7.5% to 15%, respectively). These negative effects of ALA on bortezomib's anti-MM activity were consistently observed in multiple experiments involving both of these cell lines evaluating concentrations of ALA ranging from 100 to 1000 μM and bortezomib ranging from 5 to 20 nM. Conclusions Our data suggest that ALA has the potential to antagonize the anti-MM effects of bortezomib based on our in vitro results using MM cell lines. Thus, it is possible that ALA could negatively impact the therapeutic benefit of bortezomib for MM patients and this requires further study especially if ALA is accepted as an intervention in bortezomib-related neuropathy. We are currently completing studies evaluating primary MM patients' tumor cells in vitro and our human MM xenograft models in vivo to further validate this impact of ALA on bortezomib's anti-MM activity and whether changes in treatment schedule of these drugs may prevent this inhibitory effect from occurring. In addition, because part of bortezomib's anti-tumor effects are related to reactive oxygen species (ROS) levels, we are evaluating whether the inhibitory effects of ALA on this PI may be overcome by increasing intracellular ROS levels. Disclosures: Hilger: Millennium Pharmaceutcals: Employment. Berenson:Millennium Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding, Speakers Bureau.

Cisplatin Nano-Liposomes Promoting Apoptosis of Retinoblastoma Cells Both In Vivo and In Vitro

2020 ◽  
Vol 12 (4) ◽  
pp. 536-542
Author(s):  
Lijuan Zhao ◽  
Fei Wang ◽  
Wei Fan
Keyword(s):  
Protein Expression ◽  
Nude Mice ◽  
Caspase 3 ◽  
Mrna Level ◽  
Control Group ◽  
Mrna Levels ◽  
Bax Protein ◽  
Experimental Group

This study was established to investigate the effects of cisplatin nano-liposomes on the apoptosis of the human retinoblastoma (RB) cell line Y79 in vitro and in vivo. Y79 cells were cultured and then exposed to Annexin V/PI to test their apoptosis, tested with the Caspase-3 activity detection kit to examine the change in activity of Caspase-3, and subjected to western blotting to test Bcl-2 and Bax protein expression. Y79-cell-transplanted tumor model in nude mice was also established and divided into three groups, with five nude mice in each. Cisplatin nano-liposomes were applied to the experimental group, cisplatin was injected into the control group, while saline was administered to the blank group, after which the nude mice were killed and the tumor was removed. Tumor volumes and weights in the three groups were compared. Nucleic acid extraction from magnetic beads was adopted to extract DNA, RT-PCR was employed to test Bcl-2 and Bax mRNA levels in tumor tissues, and in situ cell death assay kit was applied to test apoptotic cells. In comparison to the cisplatin solution and DMSO groups, the cisplatin liposome group showed higher Y79 apoptotic rate, Caspase-3 activity, and Bax protein expression, and lower Bcl-2 protein expression (all P < 0 05). In comparison with the control and blank groups, the experimental group showed lower tumor volume, weight, and Bcl-2 mRNA level of nude mice. In addition, in comparison with the control group, the experimental group showed higher cellular apoptotic rate and Bax mRNA level. In terms of the clinical effects of cisplatin nano-liposomes on a tumor transplant in nude mice with cervical cancer, they were shown to promote tumor apoptosis.

scholarly journals Klotho Alleviates Lung Injury Caused by Paraquat via Suppressing ROS/P38 MAPK-Regulated Inflammatory Responses and Apoptosis

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhiqiang Zhang ◽  
Qing Nian ◽  
Gang Chen ◽  
Shuqing Cui ◽  
Yuzhen Han ◽  
...  
Keyword(s):  
Lung Injury ◽  
Cell Viability ◽  
P38 Mapk ◽  
Inflammatory Responses ◽  
A549 Cells ◽  
Control Group ◽  
Ros Production ◽  
The Impact

Acute lung injury (ALI) induced by paraquat (PQ) progresses rapidly with high mortality; however, there is no effective treatment, and the specific mechanism is not well understood. The antiaging protein klotho (KL) has multiple functions and exerts significant influences on various pathophysiological processes. This work evaluated the impact of KL on PQ-induced ALI and investigated its underlying mechanisms. As for in vivo research, C57BL/6 mice were treated with PQ (30 mg/kg) intraperitoneal (IP) injection to create a toxicity model of ALI (PQ group). The mice were divided into control group, KL group, PQ group, and PQ+KL group. For in vitro experiment, A549 cells were incubated with or without KL and then treated in the presence or absence of PQ for 24 h. In vivo result indicated that KL reduced the mortality, reduced IL-1β and IL-6 in the bronchoalveolar lavage fluid (BALF), attenuated ALI, and decreased apoptosis in situ. In vitro result revealed that KL significantly improved cell viability, reduced the levels of IL-1β and IL-6 in culture supernatants, suppressed cell apoptosis, inhibited caspase-3 activation, and enhanced mitochondrial membrane potential (ΔΨm) after PQ treatment. Besides, KL effectively abated reactive oxygen species (ROS) production, improved GSH content, and lowered lipid peroxidation in PQ-exposed A549 cells. Further experiments indicated that phosphorylated JNK and P38 MAPK was increased after PQ treatment; however, KL pretreatment could significantly lower the phosphorylation of P38 MAPK. Suppression of P38 MAPK improved cell viability, alleviated inflammatory response, and reduced apoptosis-related signals; however, it had no obvious effect on the production of ROS. Treatment with N-acetylcysteine (NAC), a classic ROS scavenger, could suppress ROS production and P38 MAPK activation. These findings suggested that KL could alleviate PQ-caused ALI via inhibiting ROS/P38 MAPK signaling-regulated inflammatory responses and mitochondria-dependent apoptosis.

scholarly journals Upregulation of miR-216a-5p by Lentinan Targeted Inhibition of JAK2/STAT3 Signaling Pathway to Reduce Lung Adenocarcinoma Cell Stemness, Promote Apoptosis, and Slow Down the Lung Adenocarcinoma Mechanisms

2021 ◽  
Vol 11 ◽  
Author(s):  
Quan Chen ◽  
Yiming Zheng ◽  
Xia Chen ◽  
Pengfei Ge ◽  
Pengcheng Wang ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Signaling Pathway ◽  
Control Group ◽  
Inhibitory Effects ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway ◽  
Cell Proliferation Activity ◽  
Targeted Inhibition

To investigate the effect of Lentinan (LNT) on lung adenocarcinoma (LUAD) cell stemness and its mechanism. In this study, we founded that LNT significantly reduce the cell proliferation, activity, migration, invasion, and stemness of LUAD cells, and promote their apoptosis compared with the control group in vitro. Moreover, LNT significantly inhibited the volume and weight of tumors of nude mice in vivo. At the same time, LNT can significantly up-regulate miR-216a-5p levels and reduce the protein expression of phospho-JAK2 (Y1007/1008) and phospho-STAT3 (Tyr705), thereby inhibiting the JAK2/STAT3 signaling pathway. Interfering with miR-216a-5p expression and activating the JAK2/STAT3 signaling pathway can significantly reverse LNT inhibitory effects on LUAD. Collectively, LNT can inhibit the JAK2/STAT3 signaling pathway by up-regulating miR-216a-5p, reducing stemness, and promoting LUAD cells apoptosis, then slow down LUAD occurrence and development, providing concepts and experimental foundation treating patients with LUAD.

scholarly journals 2,5-Hexanedione mediates neuronal apoptosis through suppression of NGF via PI3K/Akt signaling in the rat sciatic nerve

2019 ◽  
Vol 39 (2) ◽  
Author(s):  
Enjun Zuo ◽  
Cong Zhang ◽  
Jun Mao ◽  
Chenxue Gao ◽  
Shuhai Hu ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Cytochrome C ◽  
Neuronal Apoptosis ◽  
Caspase 3 ◽  
Specific Inhibitor ◽  
Control Group ◽  
Cytochrome C Release ◽  
Rat Sciatic Nerve

Abstract Because precise mechanism for 2,5-hexanedione (HD)-induced neuronal apoptosis largely remains unknown, we explored the potential mechanisms both in vivo and in vitro. Rats were intraperitoneally exposed to HD at different doses for 5 weeks, following which the expression levels of nerve growth factor (NGF), phosphorylation of Akt and Bad, dimerization of Bad and Bcl-xL, as well as the release of cytochrome c and the caspase-3 activity were measured. Moreover, these variables were also examined in vitro in HD-exposed VSC4.1 cells with or without a PI3K-specific agonist (IGF-1), and in HD-exposed VSC4.1 cells with or without a PI3K-specific inhibitor (LY294002) in the presence or absence of NGF. The data indicate that, as the concentration of HD increased, rats exhibited progressive gait abnormalities, and enhanced neuronal apoptosis in the rat sciatic nerve, compared with the results observed in the control group. Furthermore, HD significantly down-regulated NGF expression in the rat sciatic nerve. Moreover, suppression of NGF expression inhibited the phosphorylation of Akt and Bad. Meanwhile, an increase in the dimerization of Bad and Bcl-xL in mitochondria resulted in cytochrome c release and caspase-3 activation. In contrast, HD-induced apoptosis was eliminated by IGF-1. Additionally, NGF supplementation reversed the decrease in phosphorylation of Akt and Bad, as well as reversing the neuronal apoptosis in HD-exposed VSC4.1 cells. However, LY294002 blocked these effects of NGF. Collectively, our results demonstrate that mitochondrial-dependent apoptosis is induced by HD through NGF suppression via the PI3K/Akt pathway both in vivo and in vitro.

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