Molecule

Description

Thymoma,Mesothelioma, Acute myeloid leukaemia

Description

Belinostat (PXD101) is a novel HDAC inhibitor with IC50 of 27 nM in HeLa cell extracts.

Targets

IC₅₀

In Vitro

Belinostat inhibits the growth of tumor cells (A2780, HCT116, HT29, WIL, CALU-3, MCF7, PC3 and HS852) with IC50 from 0.2-0.66 μM. PD101 shows low activity in A2780/cp70 and 2780AD cells, which are cisplatin and doxorubicin-resistant derivatives of A2780 cells. Belinostat could induce apoptosis through PARP cleavage and acetylation of histones H3/H4. ^[1] Belinostat inhibits bladder cancer cell growth, especially in 5637 cells, which shows accumulation of G0-G1 phase, decrease in S phase and increase in G2-M phase. ^[2] The growth inhibitory activity of belinostat on cell lines is not strongly influenced by the multidrug-resistant phenotype, whereas the activity of docetaxel is clearly affected. Belinostat could enhance the growth inhibitory activity of docetaxel or carboplatin in OVCAR-3 and A2780 cells. Belinostat also shows enhanced tubulin acetylation in ovarian cancer cell lines. ^[3] A recent study shows that Belinostat activates protein kinase A in a TGF-β signaling-dependent mechanism and decreases survivin mRNA. ^[4]

In Vivo

Belinostat indicates significant tumor growth delay in A2780 and A2780/cp70 xenograft at a dose of 10mg/kg with no effects on the body weight. ^[1] Belinostat also induces p21WAF1, HDAC core and cell communication genes in mouse bladder tumors. ^[2] Belinostat monotherapy induces dose-proportional antitumor effects with TGI of 47% at a dose of 100mg/kg in A2780 xenograft. The combination of Belinostat (100 mg/kg) with carboplatin (40 mg/kg) could delay tumor growth from 18.6 days to 22.5 days. ^[3] Combining with bortezomib, Belinostat results in great tumor inhibition and gastrointestinal toxicity in mice with bortezomib-resistant UMSCC-11A xenograft. ^[5]

Clinical Trials

Belinostat is currently in Phase II clinical trial in patients with relapsed or refractory peripheral T-cell lymphoma.

Features

Lead compound of Topotarget

Histone Deacetylase Activity

Subconfluent cultures are harvested and washed twice in ice cold PBS and pelleted by centrifugation at 200 × g for 5 min. The cell pellet is resuspended in two volumes of lysis buffer [60 mM Tris buffer (pH 7.4) containing 30% glycerol and 450 mM NaCl] and lysed by three freeze (dry ice) thaw (30 °C water bath) cycles. Cell debris is removed by centrifugation at 1.2 × 10⁴ g for 5 min, and the supernatant is stored at ?80 °C. Histone H4 peptide (sequence SGRGKGGKGLGKGGAKRHRK corresponding to the 20 NH2-terminal residues) is acetylated by a recombinant protein containing the hypoxanthine-aminopterin-thymidine domain of p300, using [³H]acetyl CoA as a source of acetate. H4 peptide (100 μg) is mixed with hypoxanthine-aminopterin-thymidine buffer (50 mM Tris HCl pH 8.0, 5% glycerol, 50 mM KCl, and 0.1 mM EDTA), 1 mM DTT, 1 mM 4-(2-aminoethyl) benzenesulfonylfluoride, 1 × complete protease inhibitors, 50 μL of purified p300, and 1.85 m [³H]acetyl CoA (4.50Ci/mmol) in a final volume of 300 μL and incubated at 30 °C for 45 min. The p300 protein is removed by incubation with 20 μL of 50% Ni-agaroase beads for 1 hour at 4 °C and cent

Cell lines

A2780, A2780/cp70, 2780AD, HCT116, HT29, WIL, CALU-3, MCF7, PC3 and HS852

Concentrations

0.016 - 10 μM

Incubation Time

24 hours

Method

Tumor cell lines are seeded in 5 mL of medium at a density of 8 × 104 cells/25 cm2 flask and incubated for 48 hours. Cells are exposed to Belinostat (0.016 to 10 μM) for 24 hours. The medium is removed, and 1 mL of trypsin/EDTA is added to each flask. Once the cells have detached, 1 mL of medium is added, the cells are resuspended, and those from the control untreated flask are counted. Cells are diluted and plated into 6-cm Petri dishes (three per flask) at a density of 0.5-2× 103 cells/dish depending on the cell line. Cells from the drug-treated flasks are diluted and plated as for the control flasks. Dishes are incubated for 10–15 days at 37 °C. Cells are washed with PBS, fixed in methanol, and stained with crystal violet, and colonies that contained ≥50 cells counted. Sensitivity is expressed as the IC50 defined as the concentration of belinostat required to reduce the number of colonies to 50% of that of the control untreated cells.

Animal Models

A2780, A2780/cp70 and HCT116 cells are injected s.c. into the right flank of CD1 nu/nu mice.

Formulation

Dissolved in DMSO and then diluted in water to give a final concentration of DMSO of 10%

Doses

≤40 mg/kg

Administration

Administered via i.p.