Biomedical subjects

Alexei Vassilev

Publications and source records attributed to Alexei Vassilev.

5 recordsLinked to original sources

PubMed2006

Anti-breast cancer activity of LFM-A13, a potent inhibitor of Polo-like kinase (PLK).

Molecular modeling studies led to the identification of LFM-A13 (alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl)propenamide) as a potent inhibitor of Polo-like kinase (Plk). LFM-A13 inhibited recombinant purified Plx1, the Xenopus homolog of Plk, in a concentration-dependent fashion, as measured by autophosphorylation and phosphorylation of a substrate Cdc25 peptide. LFM-A13 was a selective Plk inhibitor. While the human PLK3 kinase was also inhibited by LFM-A13 with an IC(50) value of 61 microM, none of the 7 other serine/threonine kinases, including CDK1, CDK2, CDK3, CHK1, IKK, MAPK1 or SAPK2a, none of the 10 tyrosine kinases, including ABL, BRK, BMX, c-KIT, FYN, IGF1R, PDGFR, JAK2, MET, or YES, or the lipid kinase PI3Kgamma were inhibited (IC(50) values >200-500 microM). The mode of Plk3 inhibition by LFM-A13 was competitive with respect to ATP with a K(i) value of 7.2 microM from Dixon plots. LFM-A13 blocked the cell division in a zebrafish (ZF) embryo model at the 16-cell stage of the embryonic development followed by total cell fusion and lysis. LFM-A13 prevented bipolar mitotic spindle assembly in human breast cancer cells and glioblastoma cells and when microinjected into living epithelial cells at the prometaphase stage of cell division, it caused a total mitotic arrest. Notably, LFM-A13-delayed tumor progression in the MMTV/neu transgenic mouse model of HER2 positive breast cancer at least as effectively as paclitaxel and gemcitabine. LFM-A13 showed a favorable toxicity profile in mice and rats. In particular there was no evidence of hematologic toxicity as documented by peripheral blood counts and bone marrow examinations. These results establish LFM-A13 as a small molecule inhibitor of Plk with in vitro and in vivo anti-proliferative activity against human breast cancer.

Amides↗

PubMed2003

Targeting JAK3 with JANEX-1 for prevention of autoimmune type 1 diabetes in NOD mice.

Here we show that Janus kinase (JAK) 3 is an important molecular target for treatment of autoimmune insulin-dependent (type 1) diabetes mellitus. The rationally designed JAK3 inhibitor JANEX-1 exhibited potent immunomodulatory activity and delayed the onset of diabetes in the NOD mouse model of autoimmune type 1 diabetes. Whereas 60% of vehicle-treated control NOD mice became diabetic by 25 weeks, the incidence of diabetes at 25 weeks was only 9% for NOD females treated with daily injections of JANEX-1 (100 mg/kg/day) from Week 10 through Week 25 (P = 0.007). Furthermore, JANEX-1 prevented the development of insulitis and diabetes in NOD-scid/scid females after adoptive transfer of splenocytes from diabetic NOD females. Chemical inhibitors such as JANEX-1 may provide the basis for effective treatment modalities against human type 1 diabetes. To our knowledge, this is the first report of the immunosuppressive activity of a JAK3 inhibitor in the context of an autoimmune disease.

Adoptive Transfer↗

PubMed2003

The anti-leukemic Bruton's tyrosine kinase inhibitor alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl) propenamide (LFM-A13) prevents fatal thromboembolism.

The leflunomide metabolite analog alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl)-propenamide (LFM-A13) is a rationally-designed specific inhibitor of the TEC family protein tyrosine kinase, Bruton's tyrosine kinase (BTK) which plays an important role in platelet physiology by regulating the glycoprotein GPVI-FcRgamma-coupled collagen receptor signaling pathway. At low micromolar concentrations, LFM-A13 inhibited collagen-induced ultrastructural changes indicative of activation. LFM-A13 inhibited collagen (but not thrombin, TRAP-6, or ADP)-induced platelet aggregation in a concentration-dependent fashion with an IC50 value of 2.8 microM. LFM-A13 was not toxic to mice when administered systemically at dose levels ranging from 1 to 100 mg/kg. At nontoxic dose levels, LFM-A13 prolonged the tail bleeding times of mice and improved event-free survival in two mouse models of agonist-induced invariably fatal pulmonary thromboembolism. To our knowledge, LFM-A13 is the first anti-thrombotic agent which prevents platelet aggregation by inhibiting BTK.

Adenosine Diphosphate↗

PubMed2002

A dual function anti-leukemic agent with anti-thrombotic activity.

Here we report that treatment with the anti-leukemic compound, LFM-A13 resulted in SYK kinase activation and caused distinct shape changes in platelets. Also provided is electron microscopic evidence that similar shape changes are observed in platelets from XID mice. We propose that LFM-A13 induces a conformational change in the PH domain of BTK and causes BTK to associate with PIP2 which effects actin bundling and shape change.

Agammaglobulinaemia Tyrosine Kinase↗

PubMed2002

In vivo pharmacokinetic features, toxicity profile, and chemosensitizing activity of alpha-cyano-beta-hydroxy-beta- methyl-N-(2,5-dibromophenyl)propenamide (LFM-A13), a novel antileukemic agent targeting Bruton's tyrosine kinase.

The purpose of the present study was to examine the in vivo pharmacokinetics and activity of alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl)propenamide (LFM-A13), a novel antileukemic agent targeting Bruton's tyrosine kinase (BTK). We have applied an analytical high-performance liquid chromatography method for the quantitative detection of LFM-A13 in plasma samples. Our findings indicate that LFM-A13 is quickly absorbed, with the time required to reach the maximum plasma drug concentration (t(max)) being 10-18 min after i.p. administration with nearly complete bioavailability. LFM-A13 had an elimination half-life of 17-32 min after i.p. administration at dose levels of 10-50 mg/kg. LFM-A13 exhibited a dose-dependent and significant increase in the values of normalized area under the curve and maximum concentration (C(max)) as well as a dose-dependent and significant decrease in clearance values, suggesting a saturable clearance mechanism. LFM-A13 was not toxic to mice when administered systemically at dose levels ranging from 10 to 80 mg/kg. Highly effective BTK-inhibitory and apoptosis-promoting plasma concentrations of LFM-A13 could be achieved in mice without toxicity. LFM-A13 exhibited a favorable pharmacokinetic behavior that was not adversely affected by the standard chemotherapy drugs vincristine, methylprednisolone, or L-asparaginase (when used as combination treatment, VPL) and significantly improved the chemotherapy response and survival outcome of mice challenged with BCL-1 leukemia cells. Whereas only 14% of mice treated with the standard triple-drug combination VPL became long-term survivors, 41% of mice treated with this combination plus LFM-A13 survived long-term. LFM-A13 prolonged the median survival time of VPL-treated mice from 37 to 58 days. Our results confirm and extend previous studies regarding the role of BTK chemotherapy resistance of B-lineage leukemic cells (S. Mahajan et al., J. Biol. Chem., 274: 9587-9599, 1999). BTK inhibitors such as LFM-A13 may be useful as a new class of chemosensitizing and apoptosis-promoting antileukemic agents for treatment of patients with chemotherapy-resistant B-lineage leukemias or lymphomas.

Agammaglobulinaemia Tyrosine Kinase↗