Related Experiment Video
Updated: Jun 24, 2026
From a 2DE-Gel Spot to Protein Function: Lesson Learned From HS1 in Chronic Lymphocytic Leukemia
Published on: October 19, 2014
Protein profiling of plasma membranes defines aberrant signaling pathways in mantle cell lymphoma
Robert S Boyd1, Rebekah Jukes-Jones, Renata Walewska
1Medical Research Council, University of Leicester, Leicester, United Kingdom.
Insights
This study identified aberrant plasma membrane and lipid raft proteins in mantle cell lymphoma (MCL) B cells. Upregulated CD70/CD27 signaling and 5-lipoxygenase (5-LO) suggest new therapeutic targets for MCL.
Area of Science:
- Oncology
- Proteomics
- Cell Biology
Background:
- Mantle cell lymphoma (MCL) is a B cell malignancy with poorly understood molecular underpinnings.
- Plasma membrane and lipid raft proteins play crucial roles in cell signaling and function.
- Identifying aberrant proteins in MCL could reveal novel therapeutic targets.
Purpose of the Study:
- To identify and characterize plasma membrane and lipid raft proteins in MCL B cells.
- To investigate the expression of specific transmembrane proteins and their role in MCL pathogenesis.
- To explore the potential of targeting identified pathways, such as leukotriene biosynthesis, for MCL treatment.
Main Methods:
- Shotgun proteomics was employed to profile plasma membrane and lipid raft proteins from MCL patient B cells.
- Bioinformatics analysis identified transmembrane proteins, followed by RT-PCR and Western blotting for validation.
- Functional studies involved assessing the impact of enzyme inhibitors (5-LO and FLAP) on MCL cell lines and primary cells.
Main Results:
- Overexpression of transmembrane proteins CD27 and CD70 was observed in MCL B cells, suggesting autocrine signaling.
- Downregulation of lipid raft proteins raftlin and Cbp/PAG was noted, while 5-lipoxygenase (5-LO) was upregulated.
- Inhibitors of 5-LO and FLAP induced apoptosis in MCL cell lines and chronic lymphocytic leukemia cells.
Conclusions:
- Aberrantly expressed plasma membrane and lipid raft proteins, including CD27, CD70, and 5-LO, are implicated in MCL pathology.
- The leukotriene biosynthetic pathway represents a potential therapeutic target for MCL and other B cell malignancies.
- Identified proteins offer promising avenues for developing novel diagnostic and therapeutic strategies for MCL.
Abstract:
We used shotgun proteomics to identify plasma membrane and lipid raft proteins purified from B cells obtained from mantle cell lymphoma (MCL) patients in leukemic phase. Bioinformatics identified 111 transmembrane proteins, some of which were profiled in primary MCL cases, MCL-derived cell lines, and normal B cells using RT-PCR and Western blotting. Several transmembrane proteins, including CD27, CD70, and CD31 (PECAM-1), were overexpressed when compared with normal B cells. CD70 was up-regulated (>10-fold) in three of five MCL patients along with its cognate receptor CD27, which was up-regulated (4-9-fold) in five of five patients, suggesting that MCL cells may undergo autocrine stimulation via this signaling pathway. Activated calpain I and protein kinase C betaII were also detected in the plasma membranes, suggesting that these proteins are constitutively active in MCL. Protein kinase C betaII has been associated with lipid rafts, and shotgun proteomics/protein profiling revealed that key lipid raft proteins, raftlin (four of five patients) and CSK (C-terminal Src kinase)-binding protein (Cbp)/phosphoprotein associated with glycosphingolipid-enriched microdomains (PAG) (four of four patients) were down-regulated in MCL. Levels of other known lipid raft proteins, such as Lyn kinase and flotillin 1, were similar to normal B cells. However, 5-lipoxygenase (5-LO), a key enzyme in leukotriene biosynthesis, was associated with lipid rafts and was up-regulated approximately 7-fold in MCL compared with normal B cells. Significantly inhibitors of 5-LO activity (AA861) and 5-LO-activating protein (FLAP) (MK886, its activating enzyme) induced apoptosis in MCL cell lines and primary chronic lymphocytic leukemia cells, indicating an important role for the leukotriene biosynthetic pathway in MCL and other B cell malignancies. Thus, using shotgun proteomics and mRNA and protein expression profiling we identified a subset of known and unknown transmembrane proteins with aberrant expression in MCL plasma membranes. These proteins may play a role in the pathology of the disease and are potential therapeutic targets in MCL.
