Abstract
The endoplasmic reticulum (ER) is responsible for the synthesis and folding of a large number of proteins, as well as intracellular calcium regulation, lipid synthesis, and lipid transfer to other organelles, and is emerging as a target for cancer therapy. However, strategies for selectively targeting the ER of cancer cells are limited. Here we show that enzymatically generated crescent-shaped supramolecular assemblies of short peptides disrupt cell membranes and target ER for selective cancer cell death. As revealed by sedimentation assay, the assemblies interact with synthetic lipid membranes. Live cell imaging confirms that the assemblies impair membrane integrity, which is further supported by lactate dehydrogenase (LDH) assays. According to transmission electron microscopy (TEM), static light scattering (SLS), and critical micelle concentration (CMC), attaching an l-amino acid at the C-terminal of a d-tripeptide results in the crescent-shaped supramolecular assemblies. Structure-activity relationship suggests that the crescent-shaped morphology is critical for interacting with membranes and for controlling cell fate. Moreover, fluorescent imaging indicates that the assemblies accumulate on the ER. Time-dependent Western blot and ELISA indicate that the accumulation causes ER stress and subsequently activates the caspase signaling cascade for cell death. As an approach for in situ generating membrane binding scaffolds (i.e., the crescent-shaped supramolecular assemblies), this work promises a new way to disrupt the membrane and to target the ER for developing anticancer therapeutics.
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📊 Figures
Figure 1.
(A) HRTEM image of nanostructures formed before and after adding ALP (1 U/mL) to the solution of 1P (0.5 wt%, scale bar = 50 nm). (B) Intensity of static light scattering (SLS) of the solutions of 1P ...
Figure 2.
The IC 50 (24 h) of 1P or 1 against HeLa cells, A2780cis cells, OVSAHO cells, and HS-5 cells.
Figure 3.
(A) The liposome binding capability of 1P (20 u03bcM ) , with or without the treatment of ALP. (B) Time dependent LDH release from the HeLa cells treated with 1P at different concentrations. Data in b...
Figure 4.
Time-lapse microscopy images of live HeLa cells after incubation with 1P (200 u03bcM) for 15 to 30 minutes, showing the dynamic disruption of cell membrane (arrows). Before incubating with 1P , the me...
Figure 5.
Cell viability of (A) HeLa and (B) HS-5 cells treated with 1P , 2P , or 3P for 24 h.
Figure 6.
(A) HRTEM images of the nanostructures formed by adding ALP to the solutions of 2P (left) and 3P (right) (0.5 wt%, scale bar = 50 nm); (B) CMCs for 2P and 3P , without or with the treatment of ALP.
Figure 7.
(A) The liposome binding capability of 1P , 2P or 3P (20 u03bcM) after the treatment of ALP; (B) Time dependent LDH release of HeLa cells after treated with 1P , 2P or 3P at 200 u03bcM. Data in both (...
Figure 8.
Time-lapse microscopy images of live HeLa cells incubating with F1P (200 u03bcM) for 0 to 70 minutes, showing the in-situ generation of assemblies of F1P on cell membrane (pink arrow), membrane disrup...
Figure 9.
Confocal laser scanning microscopy images of HeLa cells treated with F1P (200 u03bcM) for 1 h, and then stained with ER-tracker. Scale bar is 10 u03bcm.
Figure 10.
Western blot analysis of ER-stress marker (Bip, CHOP) after treating HeLa cells with 1P (50 u03bcM) at different time (i.e., 0, 3, 6, 12, 24 or 36 h).
Scheme 1.
Illustration of EISA assemblies to disrupt cell membrane and to target ER and molecular structure of an EISA precursor.
Figure images are served from the NIH/NLM PubMed Central Open Access Subset or Europe PMC; copyright remains with the publishers and authors.
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