One purpose of the study was to explore the PET tracer 11C-L-DOPA for the discrimination between small-cell lung cancer (SCLC) and non small-cell lung cancer (NSCLC). A further aim was to explore the potential antitumoral effects of 6-diazo-5-oxy-L-norleucine (DON) and the use of a PET proliferation marker for the evaluation.
Materials and methods: Four lung cancer and one endocrine tumour cell line (BON) were cultured as monolayer. The uptake of 5-[76Br]-bromo-2-fluoro-deoxyuridine (76Br-BFU), [11C]-L-DOPA (11C-DOPA) and [18F]-fluorodeoxyglucose (18FDG) were evaluated. The effects of specific enzyme inhibitors affecting the DOPA metabolism were explored. The effect of DON on proliferation and uptake of 76Br-BFU were assessed.
Results: All cell types showed a measurable uptake of 11C-DORA, with slightly lower values in lung cancer. There were no clear differences between SCLC and NSCLC. The addition of COMT inhibitor induced a significantly increased uptake of the tracer in BON cells, but not in lung cancer cells. DON significantly reduced the proliferation in all cell lines. The 76Br-BFU uptake was reduced markedly in all cell lines during DOn treatment.
Conclusion: 11C-DOPA failed to distinguish between SCLC and NSCLC. DON showed strong antiproliferative effects which might motivate renewed interest in this drug for clinical cancer treatment. PET with 76Br-BFU might be used for treatment evaluation.