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Combined phosphoproteomics and bioinformatics strategy in deciphering drug resistant related pathways in triple
Xinyu Deng1, Morris Kohanfars1, Huan Ming Hsu1
1Gonda/UCLA Breast Cancer Research Laboratory and the Revlon/UCLA Breast Center, Department of Surgery, David Geffen School of Medicine, University of California at Los Angeles, 200 Med Plaza, Ste B265-1, Los Angeles, CA 90095-7028, USA.
Abstract:
Because of the absence of a clear therapeutic target for triple negative breast cancer (TNBC), conventional chemotherapy is the only available systemic treatment option for these patients. Despite chemotherapy treatment, TNBC patients still have worse prognosis when compared with other breast cancer patients. The study is to investigate unique phosphorylated proteins expressed in chemoresistant TNBC cell lines. In the current study, twelve TNBC cell lines were subjected to drug sensitivity assays against chemotherapy drugs docetaxel, doxorubicin, gemcitabine, and cisplatin. Based on their half maximal inhibitory concentrations, four resistant and two sensitive cell lines were selected for further analysis. The phosphopeptides from these cells were enriched with TiO2 beads and fractionated using strong cation exchange. 1,645 phosphoprotein groups and 9,585 unique phosphopeptides were identified by a high throughput LC-MS/MS system LTQ-Orbitrap. The phosphopeptides were further filtered with Ascore system and 1,340 phosphoprotein groups, 2,760 unique phosphopeptides, and 4,549 unique phosphosites were identified. Our study suggested that differentially phosphorylated Cdk5, PML, AP-1, and HSF-1 might work together to promote vimentin induced epithelial to mesenchymal transition (EMT) in the drug resistant cells. EGFR and HGF were also shown to be involved in this process.
Insights
Researchers identified unique phosphorylated proteins in chemotherapy-resistant triple-negative breast cancer (TNBC) cells. These proteins, including Cdk5 and PML, may drive drug resistance by promoting epithelial to mesenchymal transition (EMT).
Area of Science:
- Oncology
- Biochemistry
- Molecular Biology
Background:
- Triple-negative breast cancer (TNBC) lacks targeted therapies, making chemotherapy the primary treatment.
- TNBC patients exhibit poorer prognoses compared to other breast cancer subtypes.
- Chemoresistance remains a significant challenge in TNBC treatment.
Purpose of the Study:
- To identify unique phosphorylated proteins in chemoresistant TNBC cell lines.
- To understand the molecular mechanisms underlying chemotherapy resistance in TNBC.
Main Methods:
- Drug sensitivity assays were performed on twelve TNBC cell lines using docetaxel, doxorubicin, gemcitabine, and cisplatin.
- Phosphopeptides were enriched, fractionated, and analyzed using high-throughput LC-MS/MS (LTQ-Orbitrap).
- Data was filtered using the Ascore system to identify phosphoprotein groups, unique phosphopeptides, and unique phosphosites.
Main Results:
- Over 1,340 phosphoprotein groups and 2,760 unique phosphopeptides were identified.
- Differentially phosphorylated proteins Cdk5, PML, AP-1, and HSF-1 were implicated.
- These proteins may collectively promote vimentin-induced epithelial to mesenchymal transition (EMT) in resistant cells.
- EGFR and HGF were also found to be involved in the chemoresistance process.
Conclusions:
- Specific protein phosphorylation patterns are associated with chemoresistance in TNBC.
- The identified proteins (Cdk5, PML, AP-1, HSF-1) may represent novel therapeutic targets.
- Understanding these pathways could lead to improved treatment strategies for TNBC patients.
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