Topotecan HCl

Stronger drug activity of Topotecan is observed for DU-145 Luc and MCF-7 Luc cells. ^[1] Topotecan causes cytotoxicity during the course of DNA replication by stabilizing the covalent complex between topoisomerase I and DNA and preventing the religation of enzyme-linked single-strand DNA break. Topotecan stabilizes topoisomerase I/DNA cleavable complexes in radiation-resistant human B-lineage acute lymphoblastic leukemia (ALL) cells, causes rapid apoptotic cell death despite high-level expression of bcl-2 protein, and inhibits ALL cell clonogenic growth in a dose-dependent fashion. ^[2]

Animals inoculate s.c. with DU-145 Luc cells and then treated with Topotecan demonstrates significant tumor growth and regression as measured with calipers and luminescent imaging. The correlation coefficient is 0.75 for the control untreated group and 0.93 for the Topotecan-treated group. Similarly, tumor progression and regression are measurable using luminescent imaging for untreated and Topotecan-treated mice inoculated i.p. with MCF-7 Luc cells. ^[1] Topotecan elicited potent antileukemic activity in severe combined immune-deficiency (SCID) mouse models of human poor prognosis ALL. Topotecan markedly improved event-free survival of SCID mice challenged with otherwise fatal doses of humaln leukemia cells at systemic drug exposure levels. ^[2] Gliomas preferentially express TRAIL R2 and that treatment with Topotecan significantly up-regulates its expression. ^[3]

• Cell lines

  MCF-7 Luc and DU-145 Luc cells

• Concentrations

  0 μg/mL - 0.692 μg/mL

• Incubation Time

  96 hours

• Method

  Topotecan is dissolved in sterile water to a stock concentration of 1 mg/mL, diluted to 6 μg/mL in cultured medium and then serially diluted 1:4 in opaque, white tissue culture-treated microplates to a final volume of 0.1 mL/well. MCF-7 Luc and DU-145 Luc cells are resuspended in 3×10⁴ cells/mL in DMEM with high glucose containing 10% FBS and 0.5 mg/mL Geneticin; 100 μL of cells are added in each well. Plates are incubated for 4 days at 37 °C in 95% humidity/5% CO₂. After incubation, 0.05 mL of 0.1 M HEPES buffer (pH 7.9) containing 50 μg/mL D-luciferin is added to each well. After incubation at room temperature for 10 minutes, the culture microplate is measured in a microplate luminometer and a molecular light imager. Results obtained with the microplate luminometer are calculated using no inhibition control wells without exogenous drug and maximum inhibition control wells containing ATP inhibitor. Results for the molecular light imager are similarly calculated using values obtained with a 5 minutes luminescent imager.

• Animal Models

  Mice with MCF-7 Luc or DU-145 Luc cells

• Dosages

  0.25 mg/mL

• Administration

  Administered via i.p.