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Badana AK, Chintala M, Gavara MM, Naik S, Kumari S, Kappala VR, Iska BR, Malla RR. Lipid rafts disruption induces apoptosis by attenuating expression of LRP6 and survivin in triple negative breast cancer. Biomed Pharmacother 2017; 97:359-368. [PMID: 29091885 DOI: 10.1016/j.biopha.2017.10.045] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 10/08/2017] [Accepted: 10/09/2017] [Indexed: 01/18/2023] Open
Abstract
Triple negative breast cancer is a clinically challenging subtype due to lack of biomarker for rational targeted therapy. Lipid rafts are cholesterol enriched rigid platforms, which colocalize signalling molecules of cancer progression. This study explores the effect of lipid rafts disruption by cholesterol depleting agent, MβCD on induction of apoptosis and expression of WNT receptor LRP6, survivin and common apoptotic markers in TNBC cell lines. The in vitro effect of lipid rafts disruption on viability, single cell reproductive ability, proliferation and migration were evaluated by MTT, clonogenic, BrdU incorporation and wound scratch assays, respectively. The morphological changes were assessed by tryphan blue, Wright and Giemsa staining; nuclear changes by Hoechst staining. The induction of apoptosis was evaluated by AO/EtBr staining, DNA damage and DNA fragmentation assays. Expression of Caveolin-1, LRP6, β-Catenin, Survivin, Bcl2, BAX, Caspase-3, Ki67 and c-myc were analyzed by PCR and Western blotting techniques. The lipid raft disruption resulted in reduction of the proliferation of MDA-MB 231 and MDA-MB 468 cells by 56.3 and 42.0%; survival fraction by 54.7 and 59.4%; migration by 44.3 and 48.4%, respectively. It also induced apoptosis by causing cell shrinkage, membrane blebbing, nuclear condensation, chromatin cleavage, oligonucleotide fragmentation with an apoptotic index of 59.1 and 46.6% in MDA-MB 231 and 468 cells, respectively. Further, it downregulated the expression of caveolin-1, LRP6, β-catenin, survivin, Bcl2, ki67, c-myc and upregulated BAX, caspase-3. The cholesterol supplementation enhanced the clonogenic potential and upregulated the expression of caveolin-1 and LRP6. The results underline a potential effect of lipid rafts disruption on induction of apoptosis in TNBC cells.
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Affiliation(s)
- Anil Kumar Badana
- Cancer Biology Research Laboratory, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India
| | - Madhuri Chintala
- Department of Obstetrics & Gynecology, Andhra Medical College, Visakhapatnam, India
| | - Murali Mohan Gavara
- Cancer Biology Research Laboratory, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India
| | - Shailender Naik
- Cancer Biology Research Laboratory, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India
| | - Seema Kumari
- Cancer Biology Research Laboratory, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India
| | | | | | - Rama Rao Malla
- Cancer Biology Research Laboratory, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India; Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India.
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Badana A, Chintala M, Varikuti G, Pudi N, Kumari S, Kappala VR, Malla RR. Lipid Raft Integrity Is Required for Survival of Triple Negative Breast Cancer Cells. J Breast Cancer 2016; 19:372-384. [PMID: 28053625 PMCID: PMC5204043 DOI: 10.4048/jbc.2016.19.4.372] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/28/2016] [Indexed: 11/30/2022] Open
Abstract
Purpose Lipid rafts are cholesterol enriched microdomains that colocalize signaling pathways involved in cell proliferation, metastasis, and angiogenesis. We examined the effect of methyl-β-cyclodextrin (MβCD)-mediated cholesterol extraction on the proliferation, adhesion, invasion, and angiogenesis of triple negative breast cancer (TNBC) cells. Methods We measured cholesterol and estimated cell toxicity. Detergent resistant membrane (DRM) and non-DRM fractions were separated using the OptiPrep gradient method. Cell cycles stages were analyzed by flow cytometry, apoptosis was assessed using the TdT-mediated dUTP nick end-labeling assay, and metastasis was determined using a Matrigel invasion assay. Neo-vessel pattern and levels of angiogenic modulators were determined using an in vitro angiogenesis assay and an angiogenesis array, respectively. Results The present study found that the cholesterol-depleting agent MβCD, efficiently depleted membrane cholesterol and caused concentration dependent (0.1–0.5 mM) cytotoxicity compared to nystatin and filipin III in TNBC cell lines, MDA-MB 231 and MDA-MB 468. A reduced proportion of caveolin-1 found in DRM fractions indicated a cholesterol extraction-induced disruption of lipid raft integrity. MβCD inhibited 52% of MDA-MB 231 cell adhesion on fibronectin and 56% of MDA-MB 468 cell adhesion on vitronectin, while invasiveness of these cells was decreased by 48% and 52% respectively, following MβCD treatment (48 hours). MβCD also caused cell cycle arrest at the G2M phase and apoptosis in MDA-MB 231 cells (25% and 58% cells, respectively) and in MDA-MB 468 cells (30% and 38% cells, respectively). We found that MβCD treated cells caused a 52% and 58% depletion of neovessel formation in both MDA-MB 231 and MDA-MB 468 cell lines, respectively. This study also demonstrated that MβCD treatment caused a respective 2.6- and 2.5-fold depletion of tyrosine protein kinase receptor (TEK) receptor tyrosine kinase levels in both TNBC cell lines. Conclusion MβCD-induced cholesterol removal enhances alterations in lipid raft integrity, which reduces TNBC cell survival.
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Affiliation(s)
- Anil Badana
- Cancer Biology Lab, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India
| | - Madhuri Chintala
- Department of Obstetrics & Gynecology, Andhra Medical College, Visakhapatnam, India
| | - Gayathri Varikuti
- Cancer Biology Lab, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India
| | - Nagaseshu Pudi
- Cancer Biology Lab, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India
| | - Seema Kumari
- Cancer Biology Lab, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India
| | - Vijaya Rachel Kappala
- Department of Biochemistry, GITAM Institute of Science, GITAM University, Visakhapatnam, India
| | - Rama Rao Malla
- Cancer Biology Lab, Department of Biochemistry, GIS, GITAM University, Visakhapatnam, India.; Department of Biochemistry, GITAM Institute of Science, GITAM University, Visakhapatnam, India
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Gandreddi VDS, Kappala VR, Zaveri K, Patnala K. Evaluating the role of a trypsin inhibitor from soap nut (Sapindus trifoliatus L. Var. Emarginatus) seeds against larval gut proteases, its purification and characterization. BMC Biochem 2015; 16:23. [PMID: 26489418 PMCID: PMC4618930 DOI: 10.1186/s12858-015-0052-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 09/30/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND The defensive capacities of plant protease Inhibitors (PI) rely on inhibition of proteases in insect guts or those secreted by microorganisms; and also prevent uncontrolled proteolysis and offer protection against proteolytic enzymes of pathogens. METHODS An array of chromatographic techniques were employed for purification, homogeneity was assessed by electrophoresis. Specificity, Ki value, nature of inhibition, complex formation was carried out by standard protocols. Action of SNTI on insect gut proteases was computationally evaluated by modeling the proteins by threading and docking studies by piper using Schrodinger tools. RESULTS We have isolated and purified Soap Nut Trypsin Inhibitor (SNTI) by acetone fractionation, ammonium sulphate precipitation, ion exchange and gel permeation chromatography. The purified inhibitor was homogeneous by both gel filtration and polyacrylamide gel electrophoresis (PAGE). SNTI exhibited a molecular weight of 29 kDa on SDS-PAGE, gel filtration and was negative to Periodic Acid Schiff's stain. SNTI inhibited trypsin and pronase of serine class. SNTI demonstrated non-competitive inhibition with a Ki value of 0.75 ± 0.05×10-10 M. The monoheaded inhibitor formed a stable complex in 1:1 molar ratio. Action of SNTI was computationally evaluated on larval gut proteases from Helicoverpa armigera and Spodoptera frugiperda. SNTI and larval gut proteases were modeled and docked using Schrodinger software. Docking studies revealed strong hydrogen bond interactions between Lys10 and Pro71, Lys299 and Met80 and Van Der Waals interactions between Leu11 and Cys76amino acid residues of SNTI and protease from H. Armigera. Strong hydrogen bonds were observed between SNTI and protease of S. frugiperda at positions Thr79 and Arg80, Asp90 and Gly73, Asp2 and Gly160 respectively. CONCLUSION We conclude that SNTI potentially inhibits larval gut proteases of insects and the kinetics exhibited by the protease inhibitor further substantiates its efficacy against serine proteases.
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Affiliation(s)
- V D Sirisha Gandreddi
- Assistant professor, Department of Biochemistry/Bioinformatics, Institute of Science, GITAM University, Rushikonda, Visakhapatnam, 530045, Andhra Pradesh, India.
| | - Vijaya Rachel Kappala
- Assistant professor, Department of Biochemistry/Bioinformatics, Institute of Science, GITAM University, Rushikonda, Visakhapatnam, 530045, Andhra Pradesh, India.
| | - Kunal Zaveri
- Assistant professor, Department of Biochemistry/Bioinformatics, Institute of Science, GITAM University, Rushikonda, Visakhapatnam, 530045, Andhra Pradesh, India.
| | - Kiranmayi Patnala
- Department of Biotechnology, Institute of Science, GITAM University, Rushikonda, Visakhapatnam, 530045, Andhra Pradesh, India.
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