MSACL 2025 Abstract

Rapid Screening and Mass Spectrometry Imaging Reveal Chemotherapy-Induced Phospholipidosis and Lipid Metabolic Reprogramming in Ovarian Cancer

Wangxing Guo (1), Amar Rai (1,2), Klaudia Mitiajew (1), Yuchen Xiang(1), Yu Wang (3), Apostolia Galani (1), Maria Paraskevaidi (1), Robert Murray (3), Maria Kyrgiou (1), Zoltan Takats (1,4) & Stefania Maneta-Stavrakaki (1)
(1) Department of Metabolism Digestion and Reproduction, Imperial College London, London, UK (2) Rosalind and Franklin Institute, Didcot, UK (3) Department of Physics, Imperial College London, London, UK (4) University of Regensburg, Regensburg, Germany

Stefania Maneta-Stavrakaki, BSc, MSc, PhD (Presenter) Imperial College London

Presenter Bio: I obtained a BSc in Chemistry from the University of Athens, followed by an MSc in Analytical Chemistry from King’s College London, mainly focused in Mass Spectrometry. I then worked as an Analytical Scientist at GSK. I completed my PhD degree in March 2022, in analytical chemistry, with specialisation in the real-time analysis of living cells using Laser Desorption Rapid Evaporative Ionisation Mass Spectrometry (LD-REIMS). I am currently funded by the CRUK Rosetta Grand Challenge and the Convergence Science Centre to study colorectal and head and neck cancers using cell lines and patient derived organoids.

Relevant Financial Disclosures (within past 24 months, reported on Apr 23, 2026) No relevant financial relationship(s) to disclose.

INTRODUCTION:
Ovarian cancer is the most lethal gynaecological cancer and is primarily treated with surgery and platinum-based chemotherapy. Most patients initially respond to treatment, but the majority eventually develop chemoresistance, leading to cancer relapse in around 80% of cases and a five-year survival rate of only 45%. Chemoresistant cells are thought to undergo lipidomic reprogramming to adapt to treatment stress and enhance resistance. Therefore, understanding lipidomic changes in chemoresistant cells is crucial for identifying therapeutic targets, which could inform personalised treatment strategies. Here, we use Desorption Electrospray Ionisation-Mass Spectrometry (DESI-MS) for the rapid screening of both sensitive and platinum-resistant ovarian cancer cells, as well as mass spectrometry imaging of ovarian cancer tissue, to investigate their lipidomic reprogramming in response to treatment.

METHODS:
The ovarian cancer cell line A2780 was exposed to increasing concentrations of cisplatin over time to generate chemoresistant clones. Sensitive and resistant cells, treated with different concentrations of cisplatin, were plated on chamber slides, and DESI-MS profiling – using a Waters Xevo G2-XS – was performed directly on the slides where the cells were grown. Minimal sample preparation was required before analysis, consisting of removing the cell culture medium and performing a single wash with ammonium acetate buffer to ensure cell integrity. DESI mass spectrometry imaging was performed in the same instrument using 25x25 µm2 spatial resolution on fresh frozen tissue sections. Data preprocessing and statistical analyses were performed using in-house developed pipelines to identify lipidomic differences and significant features.

RESULTS:
Our study reveals a progressive shift in the lipidomic profile of ovarian cancer cells with increasing cisplatin concentrations and levels of resistance. Optical imaging revealed significant morphological alterations in resistant cells, including changes in the plasma membrane and enhanced cellular adhesion. Notably, the formation of intracellular lamellar/lysosomal bodies was also observed, indicating drug-induced phospholipidosis, an established phenomenon characterised by lysosomal phospholipid accumulation, typically caused by cationic amphiphilic drugs. Although platinum-based chemotherapy agents, including cisplatin, carboplatin, and oxaliplatin, are not associated with phospholipidosis due to their lack of cationic and lipophilic properties – both of which are required to disrupt phospholipid metabolism and accumulate in lysosomes – our DESI-MS screening data revealed a significant increase in lysosomal bis(monoacylglycerol)phosphate (BMP) lipids. Specifically, BMP(40:7), BMP(44:11), and BMP(44:12) were elevated (>2-fold) in resistant clones treated with 5 and 10 µM cisplatin compared to treatment-naïve and sensitive cells. These BMP lipids serve as recognised biomarkers of phospholipidosis, suggesting a previously unreported lipid reprogramming phenomenon in cisplatin resistance. Structural confirmation of BMP lipids and their distinction from isomeric phosphatidylglycerol (PG) lipids was achieved using LC-MS/MS and authentic standards. Preliminary DESI mass spectrometry imaging (DESI-MSI) of high-grade serous ovarian carcinoma tissues from patients post-platinum chemotherapy confirmed the presence of BMP(40:8), BMP(40:7), and BMP(44:12) within the tumour region.

CONCLUSION:
In conclusion, our study utilised ambient ionisation mass spectrometry and mass spectrometry imaging to investigate lipidomic alterations in platinum-resistant ovarian cancer cells and post-chemotherapy ovarian cancer tissues. Our findings highlight severe lipid alterations in cisplatin-resistant ovarian cancer cells, featuring morphological changes and upregulation of lysosomal lipids directly linked to drug-induced phospholipidosis, a phenomenon characterised by the intracellular accumulation of phospholipids contained within lamellar bodies, most likely resulting from impaired lysosomal phospholipid metabolism.

Ongoing work includes the investigation of other chemotherapeutic agents, namely carboplatin and oxaliplatin, to determine whether our findings extend to other platinum-based chemotherapies. We will also use more clinically relevant models, specifically patient-derived organoids and ovarian cancer tissues collected from interval debulking surgery (i.e., surgery between chemotherapy treatment rounds), to validate the findings observed in the ovarian cancer cell lines. Finally, already collected blood plasma samples from ovarian cancer patients, taken before and after treatment, will also be analysed, and the results will be correlated with the in vitro and ex vivo data.

Our findings suggest that alterations in lipid metabolism and phospholipidosis may play a role in platinum resistance, as well as platinum-induced organ toxicity, such as hepatotoxicity, providing new avenues for therapeutic intervention and biomarker discovery in ovarian cancer.