Evaluation of the cytotoxicity, cell-cycle arrest, and apoptotic induction by Euphorbia hirta in MCF-7 breast cancer cells

CONTEXT: Euphorbia hirta L. (Euphorbiaceae) has been used as a folk remedy in Southeast Asia for the treatment of various ailments. OBJECTIVE: The current study evaluates the cytotoxicity, cell-cycle arrest, and apoptotic induction by E. hirta in MCF-7 breast cancer cells. MATERIALS AND METHODS: Cytotoxic activity of methanol extract of whole part of E. hirta was determined by the MTT assay at various concentrations ranging from 1.96 to 250.00 µg/mL in MCF-7 cells. Cell morphology was assessed by light and fluorescence microscopy. Apoptosis and cell-cycle distribution were determined by annexin V staining and flow cytometry. DNA fragmentation, caspase activity, and reactive oxygen species (ROS) assays were performed using the commercially available kits. To identify the cytotoxic fraction, E. hirta extract was subjected to bioassay-guided fractionation. RESULTS: Euphorbia hirta exhibited significant inhibition of the survival of MCF-7 cells and the half inhibitory concentration (IC50) values was 25.26 µg/mL at 24 h. Microscopic studies showed that E. hirta-treated cells exhibited marked morphological features characteristic of apoptosis. Euphorbia hirta extract also had an ignorable influence on the LDH leakage and generating intracellular ROS. The flow cytometry study confirmed that E. hirta extract induced apoptosis in MCF-7 cells. Euphorbia hirta also resulted in DNA fragmentation in MCF-7 cells. Moreover, E. hirta treatment resulted in the accumulation of cells at the S and G2/M phases as well as apoptosis. The caspase activity study revealed that E. hirta extract induced apoptosis through the caspase-3-independent pathway by the activation of caspase-2, 6, 8, and 9. Euphorbia hirta hexane fraction, namely HFsub4 fraction, demonstrated highest activity among all the fractions tested with an IC50 value of 10.01 µg/mL at 24 h. DISCUSSION AND CONCLUSION: This study revealed that E. hirta induced apoptotic cell death and suggests that E. hirta could be used as an apoptosis-inducing anticancer agent for breast cancer treatment with further detailed studies.

Targeting HSP90/survivin using a cell permeable structure based peptido-mimetic shepherdin in retinoblastoma

BACKGROUND: Retinoblastoma (RB) is a childhood retinal malignancy. Effective therapeutic strategies are still being investigated in RB disease management. Here, the anti-cancer effect of shepherdin, a peptido-mimetic inhibiting heat shock protein (HSP90)-Survivin interaction has been analyzed. METHODS: We analyzed HSP (HSP70/90) and Survivin protein expressions by immunohistochemistry (29 archival tumors), qRT-PCR, FACS and Western analysis (10 un-fixed RB tumors). We also analyzed cellular cytotoxicity and anti-proliferative effect in peptide treated RB cells (Y79, Weri Rb1) and MIO-M1 cells. RESULTS: Heterogeneous expressions of HSP70/90 and Survivin with a significant association between HSP70 and HSP90 (r(2) = 0.59, p = 0.001) was observed. In RB cells, anti-tumor effects were detected with 0.42 μg/ml of shepherdin at 4 h s of serum starvation. Decreased Survivin, Bcl2, MMP-2 activity with increased Bax, Bim, and Caspase-9 protein expressions were noticed. No significant changes were observed in shepherdin treated non-neoplastic MIO-M1, nor in scramble-peptide treated RB cells. CONCLUSION: The presence of HSPs (HSP70/90) and Survivin reveals multiple cellular mechanisms adopted by RB cells during cancer progression. Serum starvation induced HSP90 whose interactions with Survivin were specifically inhibited by shepherdin. The associated molecular shuffling has been reported. These findings strongly implicate the potential of targeting HSP90-Survivin interaction as an adjuvant therapy in RB management.