Ny forskningsrapport

I ett samarbetsprojekt med 9 forskare från Israel, Schweiz och Österrike har forskarna utvidgat tidigare studier om peptider som cancerläkemedel. Peptider är molekyler som ingår i en kedja av aminosyror och utgår från kroppens immunförsvar som antikroppar mot ett "främmande ämne". I det här sammanhanget cancerceller. Studier har visat att peptider kan fås att målsöka cancermarkörer i blodkärl. Problemet är att peptider enbart kan injiceras i kroppen då dessa annars bryts ner i mag-tarmkanalen som är full med enzymer med just det syftet. 

I Sverige har vi forskningsbolaget WntResearch som är inriktade på peptidstudier.

Ett gammalt "Löparn"bolag som en del av kanske kommer ihåg. Men tillbaka till aktuell studie.

The Multicellular Effects of VDAC1 N-Terminal-Derived Peptide

Published: 28 September 2022  (Pdf-versionen)

Abstract

The mitochondrial voltage-dependent anion channel-1 (VDAC1) protein functions in a variety of mitochondria-linked physiological and pathological processes, including metabolism and cell signaling, as well as in mitochondria-mediated apoptosis. VDAC1 interacts with about 150 proteins to regulate the integration of mitochondrial functions with other cellular activities. Recently, we developed VDAC1-based peptides that have multiple effects on cancer cells and tumors including apoptosis induction. Here, we designed several cell-penetrating VDAC1 N-terminal-derived peptides with the goal of identifying the shortest peptide with improved cellular stability and activity. We identified the D-Δ(1-18)N-Ter-Antp comprising the VDAC1 N-terminal region (19–26 amino acids) fused to the Antp, a cell-penetrating peptide. We demonstrated that this peptide induced apoptosis, autophagy, senescence, cell volume enlargement, and the refusion of divided daughter cells into a single cell, it was responsible for reorganization of actin and tubulin filaments, and increased cell adhesion. In addition, the peptide induced alterations in the expression of proteins associated with cell metabolism, signaling, and division, such as enhancing the expression of nuclear factor kappa B and decreasing the expression of the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha. These cellular effects may result from the peptide interfering with VDAC1 interaction with its interacting proteins, thereby blocking multiple mitochondrial/VDAC1 pathways associated with cell functions. The results of this study further support the role of VDAC1 as a mitochondrial gatekeeper protein in controlling a variety of cell functions via interaction with associated proteins.

Materials and Methods (urval)

2.6. Visualization of Cell Morphology and Division 

Cells were seeded in a 6-well plates, treated with D-Δ(1-18)N-Ter-Antp peptide for 24 h, and monitored with the Holomonitor live cell imaging system (Holographic Imaging, Lund, Sweden) for 24 h at 37 °C and 5% CO2 or with a microscope (LX2-KSP; Olympus, Shinjuku, Tokyo, Japan), with images captured by a CCD camera.

3.5. D-Δ(1-18)N-Ter-Antp Peptide Alters Cell Division 

To monitor the D-Δ(1-18)N-Ter-Antp peptide-induced cell morphological changes, we used a HoloMonitor real-time microscope for single-cell tracking of morphological cell changes induced by the peptide in Hela and U-87MG cells over 48 h, from the early stages to apoptotic cell death. This long-term time-lapse recording demonstrated a very interesting phenomena of cell division with each daughter cell with a nucleus; however, with time, the daughter cells fused (we termed re-fusion), forming a double nuclei cell (Figures 8 and A1). Monitoring the division–fusion of a single cell showed that the sequence of events started with cell division with nucleated daughter cells, followed by partial nuclei fusion, full nuclei fusion, re-fusion of these cells several hours after cytokinesis, and, finally, membrane blebbing, a hallmark of apoptosis (Figures 8A and A1). Importantly, the cell fusion events occurred almost exclusively between cells sharing the same ancestor (Figures 8A–C and A1) and not between non-related cells. The fused cells increased in size to become giant cells. The percentage of cells with re-fusion of daughter cells was time-, peptide concentration-, and cell type-dependent, with 60–80% of the U-87-MG cells showing this phenomenon following incubation for 24 h with 20 M of the peptide (Figure 8A).

Figure 8. 

D-Δ(1-18)N-Ter-Antp peptide induced apoptosis and altered cell division. (A) HeLa cells were treated with D-Δ1-18N-Ter-Antp (5 μM, 24 h) and monitored using a live-imaging microscope (HoloMonitor). 

The time course of cell division is presented. Division–fusion phase times are represented in relation to D-Δ(1-18)N-Ter-Antp administration time (T = 0). i. The cells are in a predivision stage. ii. The cell divides into two cells. iii. The cell becomes partially fused. iv. The cells become fully fused into one large cell. v. Finally, they become an apoptotic cell. (B,C) HeLa cells incubated with the peptide (10 μM, 24 h) and then stained with anti-tubulin antibodies, followed by secondary anti-mouse-cy3 antibodies (red) followed by actin staining with Phalloidin-488 (green), nuclei stained with DAPI (blue) and visualized by confocal microscopy. Cells with divided nuclei that were connected or in a re-fused state are circled (C). (D) Schematic illustration of cell division phases of control and D-Δ(1-18)N-Ter-Antp peptide-treated cells.

Figure A1. 

D-Δ(1-18)N-Ter-Antp peptide induces apoptosis and alters cell division. U-87MG cells were seeded and treated with D-Δ1-18N-Ter-Antp (5 μM, 24 h) and monitored using a live-imaging microscope (Holomonitor).

Conclusions

This study showed the multiactivity of the VDAC1-N-terminal-derived peptide in inducing cell death, autophagy, and senescence, and in altering the expression of proteins associated with cell metabolism, cell signaling, and cell division. Considering that VDAC1 interacts with over 150 proteins involved in many cell functions [8,9], the peptide’s multiple effects can be explained by interfering with the VDAC1 interaction with some of its partner proteins. These results further support the role of VDAC1 as a mitochondrial gatekeeper protein in controlling a variety of cell functions via interaction with associated proteins. Considering that most anticancer drugs target either metabolism, cell signaling cell cycle arrest, apoptosis, or autophagy [73], our findings that D-Δ(1-18)N-Ter-Antp affects all of these processes point to its potential potency as a cancer treatment.

 

Denna studie grävdes fram av Oscar. Så credden ska gå till O.

Min kommentar

Med risk för att verka tjatig, men cancerforskning och HoloMonitor är nästan synonymt.

Med instrumentet får forskare fram helt nya rön och insikter som har stor chans att leda fram till nya mer verkningsfulla cancerläkemedel. Slutsatsen i denna studie är mycket hoppfull.

                                       Mvh the99

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