Abstract 615: The effect of novel natural compounds on papillary thyroid cancer cell viability

Abstract Thyroid cancer (TC) is the most common endocrine malignancy and has been increasing in incidence in the United States over the last few decades. Incidence and mortality rates are largely owed to papillary TC (PTC), as they constitute approximately 80% of TC cases. PTC is usually contained within the thyroid gland and has an excellent prognosis, with a 5-year survival rate of more than 90% following surgery. Many survivors still need ongoing surveillance, continued treatment, and lifelong thyroid hormone supplementation, while also undergoing the consequences of current therapeutics including hormone fluctuations, surgical complications, and radioactive iodine side effects. Therefore, novel treatments, including herbal medicine, have been suggested. General Nutraceutical Technology, LLC. has a library of over 300 compounds and we screened twenty from different herbs including Glycyrrhiza glabra and Phellodendri chinensis, to name a few. Literature has supported their immunomodulatory effects and therefore we determined their dose-dependent effects at 40 ug/mL, 20ug/mL, 10ug/mL, 5ug/mL, and 2.5ug/mL on PTC cells, K1 and TPC1. Cell viability was assessed with an XTT assay over three days. Those with the lowest IC50 were further screened for synergy through the calculation of an interaction index. Initial screening demonstrated dose-dependent reductions in cell viability over three days in several of the single-blind coded compounds, plateauing at 48 hours. Compounds C35L, C7Q, and C3I were among the lowest IC50 for K1 cells at 4.4ug/mL, 9.5ug/mL, and 23 ug/mL respectively. These compounds also had the most pronounced effects on TPC1 cells with determined IC50 of 8ug/mL, 9.8ug/mL, and 23 ug/mL, respectively. Synergistic interactions were evaluated and concluded that in K1 a combination of all three compounds reduced the IC50 to 4.565ug/mL after 72 hours of treatment (II=0.57). This data warrants further investigation, including the mechanism of cell viability reduction upon treatment using Trypan Blue Exclusion, Western Blot and Flow Cytometry. Apoptosis can be assessed through the protein expression of apoptosis markers by Western Blot and Annexin V/Propidium Iodide staining by Flow Cytometry. Flow Cytometry can also determine effects on the cell cycle. Natural compounds have demonstrated long-lasting effectiveness that is safe and able to regulate multiple targets at once with advantages to Western medicine being more readily available, more convenient, and affordable. Therefore, these novel natural compounds, especially in combination, may provide safe and inexpensive relief to PTC survivors. Citation Format: Michelle Carnazza, Nan Yang, Robert Werner, Raj K. Tiwari, Jan Geliebter, Xiu-Min Li. The effect of novel natural compounds on papillary thyroid cancer cell viability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 615.