Molecule

Description

Cancer

Description

Vinflunine is a new vinca alkaloid uniquely fluorinated with the properties of mitotic-arresting and tubulin-interacting activity.

Targets

IC₅₀

In Vitro

The major effects of Vinflunine on dynamic instability are a slowing of the microtubule growth rate, an increase in growth duration, and a reduction in shortening duration. The effects of Vinflunine on the readmilling rate is examined by following [³H]GTP incorporation into MAP-rich microtubules, and the IC50 is 0.42 μM. ^[1] Vinflunine induced mitotic accumulation with IC50 with 18.8 nM, which decreases the centromere dynamicity by 44% and increases the time centromeres spent ina paused state by 63%. ^[2] Vinflunine ditartrate exhibits microtubule inhibition (purified tubulin and MTP) and cytotoxicity in L1210 cells with IC50 of (0.49 μM and 3.5 μM) and 97 nM, respectively. ^[3] Vinflunine induces apoptosis in neuroblastoma SK-N-SH cells through a postmitotic G1 arrest and a mitochondrial pathway in a concentration-dependent manner with an IC50 with 50 nM. sup>[4] Treatment of Vinflunine induces a rapid change in endothelial cell shape: cells retracts and assumes a rounded morphology. Mean IC50 values are 9.9 × 10^-5 M × 10^-5 M for fibronectin and 5.0× 10^{-5-5-8-4-7 × 10-7 M. [5]}

In Vivo

Intravenous treatment of mice with Vinflunine, immediately before and 2 day afterMatrigel implantation, results in a dose-dependent inhibition of the bFGF-induced angiogenic response, compared with vehicle-treated animals. Inhibition of haemoglobin content is significant at 1.25, 2.5 and 5 mg/kg, with no effect at 0.63 mg/kg (P > 0.05). An ID50 value (dose which inhibits 50% of bFGF-induced neovascularisation) is calculated as 1 mg/kg. Low doses of Vinflunine reduce the number of experimental liver metastases by human LS174T colon cancer cell. A slight overall decrease in liver metastatic foci is already observed at the very low dose of 0.16 mg/kg Vinflunine, although maximal overall inhibition was reached at the maximal tolerated dose (MTD) of 20 mg/kg. ^[5]

Clinical Trials

Vinflunine is now under the Phase 2 clinical trial to clarify the benefit/risk ration of cytotoxics in CDDP-unfit patients with advanced transitional cell carcinoma.

Features

Description

Vinflunine combined with Pazopanib is under the Phase 2 clinical trail in urothelial cancer of the bladder.

Determination of Microtubule Polymer Mass

Purified tubulin (17 μM) is polymerized into microtubules in the abence or presence of a range of vnflunine concentrations (35 minutes; 37 °C) in 75 mM PIPES, 1.8 mM MgCl₂, 1.0 mM EGTA, and 1.5 mM GTP (pH 6.8) using sea urchin (Strongylocentrotus purpuratus) axonemes as seeds for assembly initiation. After incubation, polymerized microtubules are separated from unpolymerized tubulin by centrifugation (150,000 × g; 1 hour; 35 °C). The supernatant is aspirated, the sedimented microtubules are depolymerized in assembly buffer by incubation on ice (2 hours), and the protein content is determined.

Microtubule Inhibition

PC-tubulin (1.8 mg/mL) is polymerized in 100 mM MES, pH 6.9, 10 mM MgSO₄, 2 mM EGTA, 1 mM GTP, and 2 M glycerol Experiments are carried out in the presence and absence of test compounds over concentration ranges of 0.1 to 1 μM. Microtubule formation is monitored using a Gilford Response II UV-Vis or a Varian Cary 3E scanning spectrophotometer equipped with a cooling Peltier cell holder. Prior to polymerization, samples are degassed on ice for 30 minutes, and baseline data are collected at 4 °C and 350 nm. The temperature was increased to 37 °C, and solutions are monitored at 350 nm for 45 minutes. Solutions are cooled to 0 °C, and a second baseline is recorded. The change in optical density is plotted vs compound concentration after subtracting the second baseline from the plateau optical density at 45 minutes. This ΔOD corresponds tothe temperature-sensitive reversible polymerization and corrects for irreversible aggregation. The percent inhibition is calculated relative to the control sample. The IC50 concentration (drug concentration causing 50% inhibition of microtubule assembly) is determined from the mean of three independent experiments.

Cell Lines

Leukemic L1210 cell

Concentrations

0-1μM

Incubation Time

48 hours

Methods

Effects of Vinflunine on L1210 cell proliferation are determined using a standard growth inhibition assay. Exponentially growing L1210 cells (1.5 × 10⁵ cells/well) in a 24-well plate are exposed to a range of concentrations of test compounds for 48 hours, prior to determining cell numbers using an electronic particle counter based on linear interpolation between data points.

Animal Models

LS174T tumor cells are injected into the spleen of BALB/C nude mice.

Formulation

Vinflunine is solubilized in a saline solution (0.9% NaCl).

Doses

~20 mg/kg

Administration

Administered via i.v. on days 4, 7, 11, 14, 18 and 21 after tumor cell implantation.