Topotecan hydrochloride hydrate

Topotecan (SKF 104864A; NSC 609669) is a Topoisomerase I inhibitor. The IC50 values of Topotecan at 24 h are 2.73±0.25 μM of U251 cells, 2.95±0.23 μM of U87 cells, 5.46±0.41 μM of GSCs-U251 and 5.95±0.24 μM of GSCs-U87.

Signaling Pathways >> Autophagy >> Autophagy

Research Areas >> Cancer

Topoisomerase I

Topotecan (SKF104864) obviously inhibits proliferation of not only human glioma cells but also glioma stem cells (GSCs) in a dose- and time-dependent manner. According to the IC50 values at 24 h, 3 μM of Topotecan (SKF104864) is selected as the optimal administration concentration. In addition, Topotecan (SKF104864) induces cell cycle arrest in G0/G1 and S phases and promoted apoptosis. Results show that the cell viability is inhibited by Topotecan (SKF104864) in a dose-dependent manner. 2, 20 and 40 μM of Topotecan obviously inhibits the cell viability compared with the control groups. The IC50 values of Topotecan (SKF104864) at 24 h are 2.73±0.25 μM of U251 cells, 2.95±0.23 μM of U87 cells, 5.46±0.41 μM of GSCs-U251 and 5.95±0.24 μM of GSCs-U87. Thus 3 μM of Topotecan is selected as the optimal administration concentration in the subsequent experiments[1].

NUB-7 metastatic model, the animals belonging to all the 4 groups are sacrificed after 14 days treatment. Compared with the control, Low dose metronomic (LDM) Topotecan (TP) and TP+Pazopanib (PZ) liver weights are significantly lower in TP+PZ-treated animals, compared with PZ. Microscopic tumors are visible in the livers of mice belonging to all the groups except TP+PZ confirming the ability of TP+PZ to control liver metastasis. In a previous dose-response study, the daily dose of oral metronomic Topotecan (0.5, 1.0, and 1.5 mg/kg) causes greater reduction in microvascular density compared with weekly maximum-tolerated dose regimen (7.5 and 15 mg/kg) in an ovarian cancer model, but the mice treated with 1.5 mg/kg daily, oral Topotecan show decreased food intake, and a lesser antitumor effect[2].

The U251, U87, GSCs-U251 and GSCs-U87 cells are seeded at a density of 2×104 cells per well in 96-well plates separately, and incubated for 24 h. Cells are administered with Shikonin and Topotecan (0.02, 0.2, 2, 20, 40 μM). After the treatment, 10 μL of cell counting kit-8 (CCK-8) is added into each well for additional 1-hour incubation at 37°C. The optical density (OD) is read with a microplate reader at 450 nm[1].

Mice[2] For subcutaneous xenograft studies, we used SK-N-BE, SH-SY5Y, KHOS, and RH30. 1×106 cells are implanted subcutaneously into the inguinal fat pad of each of nonobese diabetic/severe combined immune deficient (NOD/SCID) mice. When tumors reached 0.5 cm in diameter, the animals are randomized into 4 groups and treated daily by oral gavage. The animals are grouped as: Control group, LDM Topotecan group or LDM TP (1 mg/kg Topotecan), Pazopanib group or PZ (150 mg/kg Pazopanib) and combination group or TP+PZ (1 mg/kg Topotecan+150 mg/kg Pazopanib). To compare pulse Topotecan with LDM TP in KHOS osteosarcoma model, PZ is replaced by weekly oral dose of pulse Topotecan (SKF104864) or Pulse TP (15 mg/kg Topotecan (SKF104864)). The criteria for endpoint are tumor sizes exceeding 2.0 cm in diameter or animals showing signs of morbidity. The tumor sizes are measured on a daily basis until the endpoint or sacrifice. The long (D) and short diameters (d) are measured with calipers. Tumor volume (cm3) is calculated as V=0.5×D×d2. When the endpoint is reached or at the end of the treatment, the animals are sacrificed by cervical dislocation.

[1]. Zhang FL, et al. PLoS One. 2013 Nov 26;8(11):e81815.Topoisomerase I inhibitors, Shikonin and Topotecan, inhibit growth and induce apoptosis of glioma cells andglioma stem cells.

[2]. Kumar S, et al. Metronomic oral topotecan with pazopanib is an active antiangiogenic regimen in mouse models of aggressive pediatric solid tumor. Clin Cancer Res. 2011 Sep 1;17(17):5656-67.

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