MATERIALS AND METHODS: In the present study, the anticancer effects and the mechanisms of action of 17βH-neriifolin (cardiac glycoside) were evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and a proteomic approach in treated and non-treated SKOV-3 ovarian cancer cells.
RESULTS: 17βH-neriifolin was found to be active with IC50 values of 0.01 ± 0.001 in SKOV-3 ovarian cancer cell line, as evaluated by the sulforhodamine B (SRB) assay. RESULTS from TUNEL assay indicated that 17βH-neriifolin caused apoptosis in SKOV-3 cells in a dose-dependent manner. Based on differential analysis of treated and non-treated SKOV-3 two-dimensional electrophoresis (2-DE) profiles, four proteins, namely vimentin (VIM), pyruvate kinase, muscle (PKM), heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1) and transgelin (TAGLN1) were identified to be involved in apoptosis. Other proteins including piggybac transposable element derived 5 (PGBD5), DENN/MADD domain containing 2D (DENND2D) and formin-like 1(FMNL) have also been identified to be associated in SKOV-3 cell death induced by 17βH-neriifolin.
CONCLUSION: These findings may provide new insights on the potential of 17βH-neriifolin's mechanism of action in killing ovarian cancer cells.
METHODS: Female rats, once rendered hypothyroid via oral administration of methimazole (0.03% in drinking water) for twenty-one days were mated with fertile euthyroid male rats at 1:1 ratio. Pregnancy was confirmed by the presence of vaginal plug and this was designated as day-1. Thyroxine (20, 40 and 80 μg/kg/day) was then subcutaneously administered to pregnant, hypothyroid female rats for three days. A day after last injection (day four pregnancy), female rats were sacrificed and expression of thyroid hormone receptors (TR-α and β), retinoid X receptor (RXR) and extracellular signal-regulated kinase (ERK1/2) in uterus were quantified by Western blotting while their distribution in endometrium was visualized by immunofluorescence.
RESULTS: Expression of TRα-1, TRβ-1 and ERK1/2 proteins in uterus increased with increasing doses of thyroxine however no changes in RXR expression was observed. These proteins were found in the stroma with their distribution levels were relatively higher following thyroxine treatment.
CONCLUSIONS: Increased expression of TRα-1, TRβ-1 and ERK1/2 at day 4 pregnancy in thyroxine-treated hypothyroid pregnant rats indicate the importance of thyroxine in up-regulating expression of these proteins that could help mediate the uterine changes prior to embryo implantation.