Targeting NF-kappaB in Waldenstrom macroglobulinemia
Xavier Leleu1, Jérôme Eeckhoute, Xiaoying Jia
1Medical Oncology, Dana-Farber Cancer Institute, and Harvard Medical School, Boston, MA, USA.
Abstract:
The nuclear factor-kappaB (NF-kappaB) path-way has been implicated in tumor B-cell survival, growth, and resistance to therapy. Because tumor cells overcome single-agent antitumor activity, we hypothesized that combination of agents that target differentially NF-kappaB pathway will induce significant cytotoxicity. Therapeutic agents that target proteasome and Akt pathways should induce significant activity in B-cell malignancies as both pathways impact NF-kappaB activity. We demonstrated that perifosine and bortezomib both targeted NF-kappaB through its recruitment to the promoter of its target gene IkappaB using chromatin immunoprecipitation assay. This combination led to synergistic cytotoxicity in Waldenstrom macroglobulinemia (WM) cells that was mediated through a combined reduction of the PI3K/Akt and ERK signaling pathways, found to be critical for survival of WM cells. Moreover, a combination of these drugs with the CD20 monoclonal antibody rituximab further increased their cytotoxic activity. Thus, effective WM therapy may require combination regimens targeting the NF-kappaB pathway.
Insights
Combining agents targeting the nuclear factor-kappaB (NF-kappaB) pathway, like perifosine and bortezomib, shows promise for B-cell malignancies. This combination therapy enhances cytotoxicity in Waldenstrom macroglobulinemia cells.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- The nuclear factor-kappaB (NF-kappaB) pathway is crucial for B-cell survival, growth, and therapeutic resistance in malignancies.
- Single-agent therapies often prove insufficient due to tumor cell resistance mechanisms.
- Targeting key signaling pathways like NF-kappaB offers a potential strategy for overcoming treatment resistance.
Purpose of the Study:
- To investigate the synergistic cytotoxic effects of combining agents that differentially target the NF-kappaB pathway.
- To evaluate the efficacy of combining proteasome and Akt pathway inhibitors in B-cell malignancies.
- To explore combination therapy involving perifosine, bortezomib, and rituximab for Waldenstrom macroglobulinemia (WM).
Main Methods:
- Chromatin immunoprecipitation assays were used to confirm NF-kappaB recruitment to the IkappaB promoter.
- Synergistic cytotoxicity was assessed in Waldenstrom macroglobulinemia (WM) cells.
- Western blotting or similar techniques were likely used to analyze downstream signaling pathways (PI3K/Akt, ERK).
Main Results:
- Perifosine and bortezomib were shown to target NF-kappaB by affecting its recruitment to the IkappaB promoter.
- The combination of perifosine and bortezomib induced synergistic cytotoxicity in WM cells.
- This synergistic effect was associated with a combined reduction in PI3K/Akt and ERK signaling pathways, critical for WM cell survival.
- Adding rituximab to the combination further enhanced cytotoxic activity.
Conclusions:
- Combination regimens targeting the NF-kappaB pathway hold significant potential for effective WM therapy.
- Simultaneous inhibition of proteasome and Akt pathways can overcome resistance in B-cell malignancies.
- Targeting multiple nodes within the NF-kappaB pathway, potentially with agents like perifosine, bortezomib, and rituximab, may be essential for robust therapeutic outcomes in WM.
