Monitoring of changes in lipid profiles during PLK1 knockdown in cancer cells using DESI MS
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Updated: Mar 19, 2026
Lipid Droplet Isolation for Quantitative Mass Spectrometry Analysis
Published on: April 17, 2017
Balasubramanyam Jayashree1,2, Amitava Srimany3, Srinidhi Jayaraman1
1Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, 600006, India.
Abstract:
The importance of the polo-like kinase 1 (PLK1) gene is increasing substantially both as a biomarker and as a target for highly specific cancer therapy. This is due to its involvement in multiple points of cell progression and carcinogenesis. PLK1 inhibitors' efficacy in treating human cancers has been limited due to the lack of a specific targeting strategy. Here, we describe a method of targeted downregulation of PLK1 in cancer cells and the concomitant rapid detection of surface lipidomic perturbations using desorption electrospray ionization mass spectrometry (DESI MS). The efficient delivery of siRNA targeting PLK1 gene selectively to the cancer cells is achieved by targeting overexpressed cell surface epithelial cell adhesion molecule (EpCAM) by the EpDT3 aptamer. The chimeric aptamer (EpDT3-siPLK1) showed the knockdown of PLK1 gene expression and PLK1 protein levels by quantitative PCR and western blotting, respectively. The abundant surface lipids, phosphatidylcholines (PCs), such as PC(32:1) (m/z 754.6), PC(34:1) (m/z 782.6), and PC(36:2) (m/z 808.6), were highly expressed in MCF-7 and WERI-RB1 cancer cells compared to normal MIO-M1 cells and they were observed using DESI MS. These overexpressed cell surface lipids in the cancer cells were downregulated upon the treatment of EpDT3-siPLK1 chimera indicating a novel role of PLK1 to regulate surface lipid expression in addition to the efficient selective cancer targeting ability. Our results indicate that DESI MS has a potential ability to rapidly monitor aptamer-mediated cancer therapy and accelerate the drug discovery process. Graphical abstract Binding of aptamer chimera to the cells and changes in lipid profile.
Insights
This study introduces a novel aptamer chimera for targeted cancer therapy by downregulating polo-like kinase 1 (PLK1). Desorption electrospray ionization mass spectrometry (DESI MS) rapidly detects changes in cancer cell surface lipids, aiding therapy monitoring.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- Polo-like kinase 1 (PLK1) is crucial in cell progression and carcinogenesis, making it a significant biomarker and therapeutic target.
- Current PLK1 inhibitors face limitations in efficacy due to a lack of specific targeting strategies in cancer therapy.
Purpose of the Study:
- To develop a method for targeted downregulation of PLK1 in cancer cells using an aptamer-siRNA chimera.
- To utilize desorption electrospray ionization mass spectrometry (DESI MS) for rapid detection of surface lipidomic changes during therapy.
Main Methods:
- An EpDT3 aptamer targeting EpCAM was conjugated with siRNA against PLK1 (EpDT3-siPLK1) for selective delivery to cancer cells.
- Quantitative PCR and western blotting were used to confirm PLK1 gene and protein knockdown.
- DESI MS was employed to analyze surface lipid profiles of cancer cells before and after treatment.
Main Results:
- The EpDT3-siPLK1 chimera successfully downregulated PLK1 expression in cancer cells.
- Specific phosphatidylcholines (PCs) were found to be highly expressed on cancer cell surfaces and downregulated post-treatment.
- DESI MS demonstrated the ability to rapidly monitor these lipidomic changes.
Conclusions:
- PLK1 plays a role in regulating cancer cell surface lipid expression.
- The EpDT3-siPLK1 chimera offers an effective strategy for selective cancer targeting and therapy.
- DESI MS is a valuable tool for monitoring aptamer-mediated cancer therapy and accelerating drug discovery.
