Synergistic interactions between resveratrol and doxorubicin inhibit angiogenesis both in vitro and in vivo

Resveratrol is a polyphenolic compound which is found in many nutrients including grapes, peanuts, raspberries, and apples. Anti-proliferative, anti-angiogenic and apoptotic effects of resveratrol have been shown on various cancer cells. Doxorubicin is considered as one of the most effective anticancer agents and reveals its antitumor activity by induction of apoptosis and inhibition of angiogenesis. Our study reports for the first time the potent ability of resveratrol in combination with doxorubicin to inhibit angiogenesis in vitro and in vivo. The cytotoxic effect of resveratrol (1.56-100 μM), doxorubicin (0.01-0.92 µM) and their combination were analyzed in the human umbilical vein endothelial cells (HUVECs) by ATP assay. In vitro angiogenesis was evaluated using tube formation assay in HUVECs. In vivo anti-angiogenic activity was assessed in a chick chorioallantoic membrane (CAM) model using fertilized chicken eggs. All test groups were compared to thalidomide as a positive control, three concentrations of resveratrol (10-5-2.5 µg/pellet) and a 2 µg/pellet concentration of doxorubicin was examined. All data were evaluated statistically. Resveratrol and doxorubicin alone displayed inhibitory effects on angiogenesis and cell viability at higher doses. However, the combination of resveratrol and doxorubicin exhibited a significant dose-dependent inhibition of CAM angiogenesis in vivo as well as proliferation and tube formation in HUVECs compared to the positive control (±)-thalidomide. Our results suggest that resveratrol in combination with doxorubicin is a novel strategy in the prevention and treatment of angiogenesis.

Donkey milk kefir induces apoptosis and suppresses proliferation of Ehrlich ascites carcinoma by decreasing iNOS in mice

Donkey milk and donkey milk kefir exhibit antiproliferative, antimutagenic and antibacterial effects. We investigated the effects of donkey milk and donkey milk kefir on oxidative stress, apoptosis and proliferation in Ehrlich ascites carcinoma (EAC) in mice. Thirty-four adult male Swiss albino mice were divided into four groups as follows: group 1, administered 0.5 ml water; group 2, administered 0.5 ml water + EAC cells; group 3, administered 0.5 ml donkey milk + EAC cells; group 4, administered 0.5 ml donkey milk kefir + EAC cells. We introduced 2.5 x 10⁶ EAC cells into each animal by subcutaneous injection. Tap water, donkey milk and donkey milk kefir were administered by gavage for 10 days. Animals were sacrificed on day 11. After measuring the short and long diameters of the tumors, tissues were processed for histology. To determine oxidative stress, cell death and proliferation iNOS and eNOS, active caspase-3 and proliferating cell nuclear antigen were assessed using immunohistochemistry. A TUNEL assay also was used to detect apoptosis. Tumor volume decreased in the donkey milk kefir group compared to the control and donkey milk groups. Tumor volume increased in the donkey milk group compared to the control group. Proliferating cell nuclear antigen levels were higher in the donkey milk kefir group compared to the control and donkey milk groups. The number of apoptotic cells was less in the donkey milk group, compared to the control, whereas it was highest in the donkey milk kefir group. Donkey milk administration increased eNOS levels and decreased iNOS levels, compared to the control group. In the donkey milk kefir group, iNOS levels were significantly lower than those of the control and donkey milk groups, while eNOS levels were similar to the control group. Donkey milk kefir induced apoptosis, suppressed proliferation and decreased co-expression of iNOS and eNOS. Donkey milk promoted development of the tumors. Therefore, donkey milk kefir appears to be more beneficial for treating breast cancer than donkey milk.