Hsp90 inhibitor gedunin causes apoptosis in A549 lung cancer cells by disrupting Hsp90:Beclin-1:Bcl-2 interaction and downregulating autophagy

Hsp90 inhibitor gedunin causes apoptosis in A549 lung cancer cells by disrupting Hsp90:Beclin-1:Bcl-2 interaction and downregulating autophagy

Hsp90 is regarded as an important therapeutic target in cancer treatment. Client proteins of Hsp90 like Beclin-1, PI3K, and AKT, are associated with tumor development, poor prognosis, and resistance to cancer therapies. This study aims to analyze the role of Gedunin, an Hsp-90 inhibitor, in mediatio...

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Bibliographic Details
Published in:Life sciences (1973) Vol. 256; p. 118000
Main Authors: Hasan, Adria, Haque, Ejazul, Hameed, Rohil, Maier, Paul N., Irfan, Safia, Kamil, Mohd, Nazir, Aamir, Mir, Snober S.
Format: Journal Article
Language:English
Published: New York Elsevier Inc 01-09-2020
Elsevier BV
Subjects:
1-Phosphatidylinositol 3-kinase
AKT protein
Apoptosis
Autophagy
Bcl-2 protein
Biomarkers
Chromatin
Crosstalk
Cytotoxicity
Deoxyribonucleic acid
Disruption
DNA
Epidermal growth factor receptors
ER stress
Gedunin
Gene expression
Hsp70 protein
Hsp90
Hsp90 protein
Immunoblotting
Immunoprecipitation
Inhibitors
Lung cancer
Membrane potential
Membranes
Mitochondria
Phagocytosis
Polymerase chain reaction
Proteins
Reactive oxygen species
Therapeutic targets
Hsp90
ER stress
Autophagy
Gedunin
Apoptosis
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Summary:Hsp90 is regarded as an important therapeutic target in cancer treatment. Client proteins of Hsp90 like Beclin-1, PI3K, and AKT, are associated with tumor development, poor prognosis, and resistance to cancer therapies. This study aims to analyze the role of Gedunin, an Hsp-90 inhibitor, in mediation of crosstalk between apoptosis and autophagy by targeting Beclin-1:Bcl-2 interaction, and ER stress. A549 cells were treated with different concentrations of gedunin, and inhibitory rate was evaluated by MTT assay. Effect of gedunin on generation of reactive oxygen species, mitochondrial membrane potential, and chromatin condensation was studied by staining methods like DCFH-DA, MitoTracker, and DAPI. Expression of EGFR, PIK3CA, AKT, marker genes for apoptosis and autophagy were studied using semi-quantitative RT-PCR. Interaction study of Hsp90:Beclin-1:Bcl-2 was done by immunoprecipitation analysis. Protein expression of autophagy and apoptosis markers along with Grp78, Hsp70, and Hsp90 was analyzed by immunoblotting. Gedunin exerts cytotoxic effects, causes increase in ROS generation, downregulates mitochondrial membrane potential and induces loss in DNA integrity. mRNA expression analysis revealed that gedunin sensitized A549 cells towards apoptosis by downregulating EGFR, PIK3CA, AKT, and autophagy. Gedunin also inhibited interaction between Hsp90:Beclin-1:Bcl-2, leading to downregulation of autophagy (Beclin-1, Atg5-12 complex, and LC3) and antiapoptotic protein Bcl-2, which may result in ER stress-induced apoptosis. Moreover, Hsp90 inhibition by gedunin did not cause upregulation of Hsp70 expression. Gedunin induces apoptosis in lung cancer cells by disrupting Hsp90:Beclin-1:Bcl-2 interaction and autophagy downregulation, thus making gedunin a good drug lead for targeting lung cancer. •Hsp90 is an essential and highly abundant protein overexpressed in lung cancer.•Hsp90 client proteins help in cancer progression.•Hsp90 inhibitors targeting client proteins can help develop anti-cancer therapy.•Hsp90 inhibition caused autophagy inhibition by breaking Hsp90:Beclin-1:Bcl-2.•Lung cancer cells were chemo-sensitized towards ER-mediated apoptosis.
ISSN:0024-3205
1879-0631
DOI:10.1016/j.lfs.2020.118000