The Effect Of BKM120Combined With Doceraxel And Trastuzumab On Human Breast Cancer Cells And Stem Cells In Vitro And In Vivo

Objective:1. To analyse the antitumor activity ofthepan-class IA PI3K inhibitor NVP-BKM120in breast cancer stem cells and total cells.The effects of BKM120inbreast cancer stem cells in vivo wasassessed2. To evaluate the combining effects of NVP-BKM120and docetaxel in vitro in stem cells of three breast cancer cells3. To test the activity of the combination therapy with docetaxelin vivo.4. To investigatethe combining effects of BKM120and trastuzumab in stem cells of HER-2+breast cancerin vitro.Methods:1. In vitro studies, we isolatedmammospheres cells as stem cells usingserum-free suspension culturefrom MDA-MB-231,MCF-7,and SK-BR-3cell lines. The ratio of cells with a phenotype of ESA+CD44+CD24-/low in mammospheres was ananlysed by flow cytometry.And the inhibitory effect of BKM120and combine with docetaxel/trastuzumabon stem cells and total cells were quantified by MTT assays.The influence of BKM120and combine with docetaxel/trastuzumab on migration and invasion abilities of three breast cancer cellswas detected by scrape migration assay.Treatment with BKM120alone or combine with docetaxel/trastuzumab, the proliferation of breast cacner cells was measured by plate clone formation assay.The mammosphere formationefficiency of three breast cancer cells cultured with BKM120or combinationtherapy was also investigated.The expression of total Akt, p-Akt (Thr308, Ser473),total S6,pS6in cells treatment with BKM120, docetaxel, trastuzumab alone and in combination were detected by Western blot analysis.2. In vivo studies, breast cancer stem cells wereinjected into the fat pads ofBALB/c miceand different treatments were administered.After treatment of xenograft models with agent alone or in conbination, the volumes of the xenograft tumors and the weightof mice were measured every3days.Results:1. BKM120could inhibit the growth of allthree breast cancer stem cellsina dose-dependent manner.More, the drug could also decreased the migration ability, the mammosphere formation efficiency(MFE),clonogenic survival.And compared with control group,the volumes of the xenograft tumors decreased significantly in BKM120alone group, in vivo.2. Theeffects of BKM120combination with docetaxel in breast cancer cells and stem cells:Compared with groups treatment with agent alone,we observed anenhanced growth inhibitory effect of the combination treatment on all three breast cacner cells and stem cells in vitro. More, the migration and invasion abilities, MFE,the clonogenic survivaldecreased more in the combination treatment group when compared with either single-agent group. In vivo,BKM120plus docetaxel therapy show much more effective at reducing tumor volume in mice compared with either single-agent alone.Conclusions:1. BKM120couldeffective inhibitall three breast cancer cells and theisolated stem cells growth in vitro and in vivo.2. BKM120plus docetaxel can inhibit the growth of breast cancer cells and stem cells in vitro and in vivo by inhibiting PI3K/AKT pathway and reducing MFE,migration ability.which is a potential combination treatment that may be promising in human clinical trials.3. BKM120plus trastuzumab shows effective inhibitory effects on HER2+breast cancer stem cells in vitro.