LC-HRMS-based global metabolomics profiling unravels the distinct metabolic signature of lapatinib-resistant and trastuzumab-resistant HER2+breast cancer cells

The effectiveness of lapatinib (LAP) and trastuzumab (TRZ), the first-line therapies for HER2+ breast cancer, has been limited owing to the development of acquired resistance in patients with HER2+. This study aimed to investigate the alterations in metabolic signatures in LAP-resistant HCC1954 and TRZ-resistant HCC1954 and pathways in human HER2+ breast cancer cells using liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and enrichment analysis. The HCC1954 parental cells were sequentially treated 13 rounds with LAP or TRZ to develop resistant cells and then tested for their cytotoxicity using the MTT assay. Metabolites were prepared from HCC1954 parental (MBXWT), HCC1954-LAP (MBXLAP), and HCC1954-TRZ (MBXTRZ) cells prior to LC-HRMS, chemometric, enrichment, and joint pathway analyses. LAP- and TRZ-resistant cells were successfully developed from HCC1954, and 29 and 17 differentially expressed metabolites (DEMs) were identified between MBXWT-MBXLAP and MBXWT-MBXTRZ, respectively. The analysis of DEMs between MBXWT and MBXLAP revealed significant enrichment in D-amino acid metabolism, while MBXWT and MBXTRZ identified valine, leucine, isoleucine biosynthesis, ascorbate, and aldarate metabolism. Joint pathway enrichment analysis of LAP-resistant DEMs and differentially expressed genes (DEGs) showed enrichment in glutathione metabolism, while that of TRZ-resistance and DEGs showed enrichment in carbohydrate metabolism, namely pentose and glucuronate interconversions, starch and sucrose metabolism, and galactose metabolism. The findings from this study indicate considerable metabolic changes in LAP- and TRZ-resistant HCC1954 cells, which are crucial for understanding the resistance mechanisms and developing strategies to overcome these problems.