Figure 3. mir-93 promotes tumor growth by increasing CSCs in MCF7 cells.

A. Mir-93 is expressed equally in CD24⁻CD44⁺ and bulk (non-CD24⁻CD44⁺) populations of MCF7 cells. B. 1×10⁶ pTRIPZ-MCF7-mir-93 cells were plated in T75 flasks and, after overnight, the cells were treated with Vehicle control, DOX (1 ug/ml), docetaxel (10 nM) or the combination for 7 days. DOX alone, docetaxel alone or the combination increased the CD24⁻CD44⁺ population in vitro. C. 1000k pTRIPZ-MCF7-mir-93 cells were injected into the 4^th fatpads of NOD/SCID mice. Treatment was initiated as indicated by the red arrow. DOX alone (1 mg/ml in drinking water) promoted MCF7 tumor growth in vivo; docetaxel (10 mg/kg i.p. once weekly) alone or the combination inhibits MCF7 tumor growth in vivo. D. Tumors from each group were collected. Analysis for CD24 and CD44 was performed on dissociated cells. DOX alone, docetaxel alone, or the combination increased the CD24⁻CD44⁺ populations in MCF7. E. Serial dilutions of cells obtained from these xenografts were implanted in the 4^th fatpads of secondary mice, which received no further treatment. Cells from DOX-, docetaxel-, or combination-treated tumors formed secondary tumors at all dilutions (50000, 5000, 500), whereas only higher numbers of cells (50000, 5000) obtained from control xenografts were able to generate tumors. *p<0.05; Error bars represent mean ± STDEV. The colored “*” on the side of the tumor growth curve indicates that tumor growth is significantly different between the control group and the group with the same colored curve.