Targeting Notch1 and proteasome as an effective strategy to suppress T-cell lymphoproliferative neoplasms

Area of Science:

• Oncology
• Molecular Biology
• Cancer Therapeutics

Background:

• T-cell lymphoproliferative neoplasms (T-LPN) are aggressive hematologic malignancies with poor prognoses.
• Current treatments for T-LPN lack specificity and often cause significant side effects.
• NOTCH1 activation mutations are frequently observed in T-LPN, presenting a potential therapeutic target.

Purpose of the Study:

• To investigate the efficacy and safety of combining a γ-secretase inhibitor (GSI) with bortezomib (BTZ) for treating T-LPN.
• To evaluate the synergistic effects of GSI and BTZ on T-LPN cell lines and primary patient cells.
• To explore the impact of combination therapy on key signaling pathways involved in T-LPN survival.

Main Methods:

• In vitro analysis of T-LPN cell lines treated with GSI-I and BTZ, alone and in combination.
• Assessment of cell viability, proliferation, colony formation, and apoptosis.
• In vivo studies using a mouse model of T-LPN to evaluate tumor growth inhibition.
• Analysis of signaling pathway deregulation, including Notch1, AKT, ERK, JNK, p38 MAPK, and NF-κB.

Main Results:

• GSI-I and BTZ demonstrated synergistic effects in decreasing T-LPN cell viability, proliferation, and colony formation.
• Combination treatment induced apoptosis in T-LPN cell lines and reduced viability in primary patient cells.
• Dual inhibition effectively suppressed T-LPN tumor growth in vivo.
• The combination therapy was superior to single-agent treatment at low concentrations.

Conclusions:

• A combination of low-dose GSI-I and BTZ exhibits significant synergistic antitumor activity against T-LPN.
• This dual inhibition strategy effectively targets key survival pathways in T-LPN.
• The findings provide a strong rationale for utilizing combined Notch1 and proteasome inhibition in T-LPN treatment.