Introduction: Adjuvant Gemcitabine have recently been shown to improve progression free survival in some types of leiomyosarcoma. Adequate cellular uptake of the drug remains a challenge. We aimed to evaluate the role of nucleoside transporter activator (I3C) in increasing the in vitro efficacy of gemcitabine in the treatment of leimyosarcoma.

Methods: Leiomyosarcoma cells (SKLMS) were incubated with DMEM+10% FBS + 1% Antibiotics. Dose response curves were generated for gemcitabine and I3C to identify the IC-50 values. Triplicates of cells were then plated in 96 well plates (3000 cells/well) and allowed to adhere. The adherent cells were further treated with gemcitabine in the presence or absence of I3C and compared with controls (DMSO treatment). MTS cell viability assays were done and absorbance was monitored in a micro-plate reader. Flow cytometry was performed with Propidium Iodide (PI) staining. Scratch assays were done to assess cell migration.

Results: Viability assay showed significant increase in the cytotoxicity of gemcitabine in presence of I3C compared to controls. Flow cytometry data showed gemcitabine alone treatment has arrested the cell cycle at G0/G1 phase without increase of cell death. On the contrary, use of gemcitabine in combination with I3C increased the cell death by at least three folds compared to control as well as gemcitabine alone treated cell population. Scratch assay over a 16 hour period showed that the rate of cellular migration significantly dropped by 1.5 folds upon treatment with gemcitabine combined with I3C compared to gemcitabine alone. Western blots showed increased expression of membrane transporter hENT-1 with I3C treatment.

Conclusion: The use of I3C enhanced cellular uptake, transport and cytotoxicity of gemcitabine in SKLMS cells. Further studies are warranted and underway to elaborate on intracellular mechanisms of action to optimize the use of I3C as a potential adjunct in preclinical and clinical leiomyosarcoma treatment.

Note: This abstract was not presented at the meeting.

Citation Format: Sujit Suwal, Alexandra Moran, Ana Paz-Mejia, Lorena Flor, Omar Picado, Basem Azab, Jonathan Trent, Fiorella Pendola, Alan S. Livingstone, Danny Yakoub. Indole-3-carbinol (I3C) enhances efficacy of Gemcitabine in leiomyosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4292. doi:10.1158/1538-7445.AM2017-4292