The role of cholesterol on triterpenoid saponin-induced endolysosomal escape of a saporin-based immunotoxin
The role of cholesterol on triterpenoid saponin-induced endolysosomal escape of a saporin-based immunotoxin
Cholesterol seems to play a central role in the augmentation of saporin-based immunotoxin (IT) cytotoxicity by triterpenoid saponins. Endolysosomal escape has been proposed as one mechanism for the saponin-mediated enhancement of targeted toxins. We investigated the effects of lipid depletion followed by repletion on Saponinum album (SA)-induced endolysosomal escape of Alexa Fluor labelled saporin and the saporin-based immunotoxin OKT10-SAP, directed against CD38, in Daudi lymphoma cells. Lipid deprived cells showed reduced SA-induced endolysosomal escape at two concentrations of SA, as determined by a flow cytometric method. The repletion of membrane cholesterol by low density lipoprotein (LDL) restored SA-induced endolysosomal escape at a concentration of 5 µg/mL SA but not at 1 µg/mL SA. When LDL was used to restore the cholesterol levels in lipid deprived cells, the SA augmentation of OKT10-SAP cytotoxicity was partially restored at 1 µg/mL SA and fully restored at 5 µg/mL SA. These results suggest that different mechanisms of action might be involved for the two different concentrations of SA and that endosomal escape may not be the main mechanism for the augmentation of saporin IT cytotoxicity by SA at the sub-lytic concentration of 1 µg/mL SA.
ADP-ribosyl Cyclase 1/metabolism, Cell Line, Tumor, Cell Membrane/chemistry, Cell Membrane Permeability/drug effects, Cholesterol/chemistry, Cholesterol, LDL/pharmacology, Dose-Response Relationship, Drug, Endosomes/chemistry, Fluoresceins/chemistry, Fluorescent Dyes/chemistry, Humans, Immunotoxins/chemistry, Lymphocytes/chemistry, Lysosomes/chemistry, Membrane Glycoproteins/metabolism, Saponins/pharmacology, Saporins/chemistry, Sulfonic Acids/chemistry, Triterpenes/pharmacology
Smith, Wendy S
83c13f47-f5f9-47dc-9dc8-ee4e486030da
Johnston, David A
b41163c9-b9d2-425c-af99-2a357204014e
Wensley, Harrison J
0a8a2519-6821-491c-9fd6-6f2155212a34
Holmes, Suzanne E
df2f1eed-45a4-4caf-ac64-542d91558bd1
Flavell, Sopsamorn U
fa2b4670-1836-42e2-b68a-5d646899d711
Flavell, David J
3a0f7124-7d44-42bc-b6f6-6fb12552fbd6
19 November 2020
Smith, Wendy S
83c13f47-f5f9-47dc-9dc8-ee4e486030da
Johnston, David A
b41163c9-b9d2-425c-af99-2a357204014e
Wensley, Harrison J
0a8a2519-6821-491c-9fd6-6f2155212a34
Holmes, Suzanne E
df2f1eed-45a4-4caf-ac64-542d91558bd1
Flavell, Sopsamorn U
fa2b4670-1836-42e2-b68a-5d646899d711
Flavell, David J
3a0f7124-7d44-42bc-b6f6-6fb12552fbd6
Smith, Wendy S, Johnston, David A, Wensley, Harrison J, Holmes, Suzanne E, Flavell, Sopsamorn U and Flavell, David J
(2020)
The role of cholesterol on triterpenoid saponin-induced endolysosomal escape of a saporin-based immunotoxin.
International Journal of Molecular Sciences, 21 (22), [22].
(doi:10.3390/ijms21228734).
Abstract
Cholesterol seems to play a central role in the augmentation of saporin-based immunotoxin (IT) cytotoxicity by triterpenoid saponins. Endolysosomal escape has been proposed as one mechanism for the saponin-mediated enhancement of targeted toxins. We investigated the effects of lipid depletion followed by repletion on Saponinum album (SA)-induced endolysosomal escape of Alexa Fluor labelled saporin and the saporin-based immunotoxin OKT10-SAP, directed against CD38, in Daudi lymphoma cells. Lipid deprived cells showed reduced SA-induced endolysosomal escape at two concentrations of SA, as determined by a flow cytometric method. The repletion of membrane cholesterol by low density lipoprotein (LDL) restored SA-induced endolysosomal escape at a concentration of 5 µg/mL SA but not at 1 µg/mL SA. When LDL was used to restore the cholesterol levels in lipid deprived cells, the SA augmentation of OKT10-SAP cytotoxicity was partially restored at 1 µg/mL SA and fully restored at 5 µg/mL SA. These results suggest that different mechanisms of action might be involved for the two different concentrations of SA and that endosomal escape may not be the main mechanism for the augmentation of saporin IT cytotoxicity by SA at the sub-lytic concentration of 1 µg/mL SA.
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Accepted/In Press date: 16 November 2020
Published date: 19 November 2020
Keywords:
ADP-ribosyl Cyclase 1/metabolism, Cell Line, Tumor, Cell Membrane/chemistry, Cell Membrane Permeability/drug effects, Cholesterol/chemistry, Cholesterol, LDL/pharmacology, Dose-Response Relationship, Drug, Endosomes/chemistry, Fluoresceins/chemistry, Fluorescent Dyes/chemistry, Humans, Immunotoxins/chemistry, Lymphocytes/chemistry, Lysosomes/chemistry, Membrane Glycoproteins/metabolism, Saponins/pharmacology, Saporins/chemistry, Sulfonic Acids/chemistry, Triterpenes/pharmacology
Identifiers
Local EPrints ID: 468871
URI: http://eprints.soton.ac.uk/id/eprint/468871
ISSN: 1422-0067
PURE UUID: 72ef2dee-6265-4385-8010-3152ad48e5eb
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Date deposited: 30 Aug 2022 16:59
Last modified: 17 Mar 2024 03:11
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Author:
Wendy S Smith
Author:
David A Johnston
Author:
Harrison J Wensley
Author:
Suzanne E Holmes
Author:
Sopsamorn U Flavell
Author:
David J Flavell
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