Hsp90 inhibitors repress KS tumor growth.

<p>(A) Colony formation assay of L1T2 cells after drug treatment. 400 L1T2 cells were seeded in 10 cm dishes, followed by addition of two-fold serially-diluted Hsp90 inhibitors; 17-DMAG, PU-H71, AUY922, BIIB021, and NVP-BEP800, respectively for two weeks. Colonies were counted after incubation with Magic Blue Staining, each experiment was repeated three times. (B) Hsp90 inhibitors induce G0/G1 arrest of L1T2 cells. L1T2 cells were treated with 0.5 µM of 17-DMAG, PU-H71, NVP-BEP800, BIB021, or 0.05 µM AUY922 for 24 hours, DMSO treatment was used as control. After cells were fixed and stained with propidium iodide, cell-cycle analysis was performed using flow cytometry. The percentages of cells at different stages in the cell cycle (G0/G1, S, G2/M) are shown. (C) Growth curves of tumor volume. 10⁵ L1T2 cells were injected sub-cutaneously into C.B.-17 SCID mice with mixed Matrigel (1∶1) for three days, followed by AUY922 intra-peritoneal injection at doses of 50 mg/kg NVP-AUY922 for total three weeks (three times per week), tumor volumes of SCID mice were measured and analyzed. Two groups were analyzed and each group had six mice, mock-treated mice were used as control.