Combined Treatment of Uterine Leiomyosarcoma with Gamma Secretase Inhibitor MK-0752 and Chemotherapeutic Agents Decreases Cellular Invasion and Increases Apoptosis

Due to limited effective therapeutics for uterine leiomyosarcoma (uLMS), the impact of the gamma secretase inhibitor (GSI) MK-0752 with common chemotherapeutics was explored in uLMS. MTT assays were performed on two human uLMS cell lines, SK-UT-1B and SK-LMS-1, using MK-0752, docetaxel, doxorubicin, and gemcitabine, individually and in combination, to determine cell viability after treatment. Synergistic combinations were used in transwell invasion assays, cell cycle flow cytometry, proliferation assays, and RNA sequencing. In SK-UT-1B, MK-0752 was synergistic with doxorubicin and gemcitabine plus docetaxel. In SK-LMS-1, MK-0752 was synergistic with all individual agents and with the combination of gemcitabine plus docetaxel. MK-0752, gemcitabine, and docetaxel decreased invasion in SK-UT-1B 2.1-fold* and in SK-LMS-1 1.7-fold*. In SK-LMS-1, invasion decreased 1.2-fold* after treatment with MK-0752 and docetaxel and 2.2-fold* after treatment with MK-0752 and doxorubicin. Cell cycle analysis demonstrated increases in the apoptotic sub-G1 population with MK-0752 alone in SK-UT-1B (1.4-fold*) and SK-LMS-1 (2.7-fold**), along with increases with all combinations in both cell lines. The combination treatments had limited effects on proliferation, while MK-0752 alone decreased proliferation in SK-LMS-1 (0.63-fold**). Both MK-0752 alone and in combination altered gene expression and KEGG pathways. In conclusion, the combinations of MK-0752 with either doxorubicin, docetaxel, or gemcitabine plus docetaxel are potential novel therapeutic approaches for uLMS. (* p < 0.05, ** p < 0.01).

Notch signaling; apoptosis; chemotherapy; gamma secretase inhibitors; invasion; proliferation; synergism; uterine leiomyosarcoma.