Targeting of Glucose Transport and the NAD Pathway in Neuroendocrine Tumor (NET) Cells Reveals New Treatment Options

Area of Science:

• Oncology
• Metabolic pathways
• Drug discovery

Background:

• Neuroendocrine tumors (NETs) and small cell lung cancer (SCLC) are aggressive malignancies.
• Glucose metabolism plays a crucial role in tumor cell proliferation and survival.
• Targeting glucose transporters (GLUT) and nicotinamide phosphoribosyltransferase (NAMPT) presents a potential therapeutic strategy.

Purpose of the Study:

• To evaluate the efficacy of GLUT and NAMPT inhibitors in NET and SCLC cell lines.
• To investigate the role of the Preiss-Handler salvage pathway in NAMPT inhibitor resistance.
• To determine the specificity of NAMPT inhibitors in inhibiting glucose uptake in NET cells.

Main Methods:

• Treatment of NET (BON-1, QPG-1) and SCLC (GLC-2, GLC-36) cell lines with GLUT inhibitors (fasentin, WZB1127) and NAMPT inhibitors (GMX1778, STF-31).
• Assessment of tumor cell proliferation and survival rates.
• Nicotinic acid rescue experiments to evaluate the Preiss-Handler salvage pathway.
• Glucose uptake assays to analyze drug specificity.

Main Results:

• GLUT and NAMPT inhibitors significantly affected tumor cell proliferation and survival.
• NET cell lines treated with NAMPT inhibitors could not be rescued by nicotinic acid, despite detectable NAPRT expression.
• GMX1778 and STF-31 specifically inhibited glucose uptake in NET cells at higher concentrations (50 μM), but not lower (5 μM).

Conclusions:

• NAMPT inhibitors, particularly, show promise as a therapeutic strategy for neuroendocrine tumors.
• Understanding drug specificity and potential resistance mechanisms is crucial for optimizing treatment.
• Further research into GLUT and NAMPT inhibitors could lead to novel NET therapies.