OTS964

OTS964{(R)-9-(4-(1-(dimethylamino)propan-2-yl)phenyl)-8-hydroxy-6-methylthieno[2,3-c] quinolin-4(5H)-one} is a potent TOPK inhibitor with an IC50 value of 28 nM. It is a dimethylated derivative of OTS514. OTS964 can inhibit TOPK kinase activity with high affinity and selectivity. TOPK (T-lymphokine-activated killer cell-originated protein kinase) is a protein that is found in a wide range of human cancers and is believed to work as an oncogene, promoting tumor growth.

It has been reported that OTS964 inhibited the growth of TOPK-positive cells with low IC50 values [A549 (31 nM), LU-99 (7.6 nM), DU4475 (53 nM), MDA-MB-231 (73 nM), T47D (72 nM), Daudi (25 nM), UM-UC-3 (32 nM), HCT-116(33nM), MKN1(38nM), MKN45(39nM), HepG2(19nM), MIAPaca-2 (30 nM), and 22Rv1 (50 nM)]. However, its growth inhibitory effect against TOPK-negative HT29 cancer cells was significantly weaker, with IC50 value of 290 nM. Intravenous administration of OTS964 at 40 mg/kg on days 1, 4, 8, 11, 15, and 18 to mice bearing LU-99 lung cancer cells, a TGI of 44% was observed on day 22 without any body weight loss. The differentiation of HSCs to amega-karyocyte population was also enhanced by OTS964 treatment ¹.

References:
1. Matsuo Y, Park JH2, Miyamoto T, et al. TOPK inhibitor induces complete tumor regression in xenograft models of human cancer through inhibition of cytokinesis. ci Transl Med. 2014 Oct 22;6(259):259ra145.

TOPK inhibitor induces complete tumor regression in xenograft models of human cancer through inhibition of cytokinesis.[Pubmed:25338756]

Sci Transl Med. 2014 Oct 22;6(259):259ra145.

TOPK (T-lymphokine-activated killer cell-originated protein kinase) is highly and frequently transactivated in various cancer tissues, including lung and triple-negative breast cancers, and plays an indispensable role in the mitosis of cancer cells. We report the development of a potent TOPK inhibitor, OTS964 {(R)-9-(4-(1-(dimethylamino)propan-2-yl)phenyl)-8-hydroxy-6-methylthieno[2,3-c]qu inolin-4(5H)-one}, which inhibits TOPK kinase activity with high affinity and selectivity. Similar to the knockdown effect of TOPK small interfering RNAs (siRNAs), this inhibitor causes a cytokinesis defect and the subsequent apoptosis of cancer cells in vitro as well as in xenograft models of human lung cancer. Although administration of the free compound induced hematopoietic adverse reactions (leukocytopenia associated with thrombocytosis), the drug delivered in a liposomal formulation effectively caused complete regression of transplanted tumors without showing any adverse reactions in mice. Our results suggest that the inhibition of TOPK activity may be a viable therapeutic option for the treatment of various human cancers.

T-LAK Cell-Originated Protein Kinase (TOPK) as a Prognostic Factor and a Potential Therapeutic Target in Ovarian Cancer.[Pubmed:27334838]

Clin Cancer Res. 2016 Dec 15;22(24):6110-6117.

BACKGROUND: We aimed to clarify the clinical significance of TOPK (T-lymphokine-activated killer cell-originated protein kinase) expression in ovarian cancer and evaluate the possible effect of TOPK inhibitors, OTS514 and OTS964, on ovarian cancer cells. METHODS: TOPK expression was examined by immunohistochemistry using 163 samples with epithelial ovarian cancer (EOC). TOPK protein level and FOXM1 transcriptional level in ovarian cancer cell lines were examined by Western blot and RT-PCR, respectively. Half-maximum inhibitory concentration (IC50) values against TOPK inhibitors were examined by the MTT assay. Using the peritoneal dissemination model of ES-2 ovarian cancer cells, we examined the in vivo efficacy of OTS514. In addition, the cytotoxic effect of OTS514 and OTS964 on 31 patient-derived primary ovarian cancer cells was examined. RESULTS: TOPK was expressed very highly in 84 (52%) of 163 EOC tissues, and high TOPK expression was significantly associated with poor progression-free survival and overall survival in early-stage cases of EOC (P = 0.008 and 0.006, respectively). Both OTS514 and OTS964 showed significant growth-inhibitory effect on ovarian cancer cell lines with IC50 values of 3.0 to 46 nmol/L and 14 to 110 nmol/L, respectively. TOPK protein and transcriptional levels of FOXM1 were reduced by TOPK inhibitor treatment. Oral administration of OTS514 significantly elongated overall survival in the ES-2 abdominal dissemination xenograft model, compared with vehicle control (P < 0.001). Two drugs showed strong growth-inhibitory effect on primary ovarian cancer cells regardless of tumor sites or histological subtypes. CONCLUSIONS: Our results demonstrated the clinical significance of high TOPK expression and potential of TOPK inhibitors to treat ovarian cancer. Clin Cancer Res; 22(24); 6110-7. (c)2016 AACR.

Novel molecule targets cytokinesis.[Pubmed:25583820]

Cancer Discov. 2015 Jan;5(1):OF8.

Researchers have identified a new compound, OTS964, that blocks cytokinesis. Injections of the compound eliminated human lung tumors that had been transplanted into mice. Clinical trials of OTS964 may start next year.

TOPK modulates tumour-specific radiosensitivity and correlates with recurrence after prostate radiotherapy.[Pubmed:28677687]

Br J Cancer. 2017 Aug 8;117(4):503-512.

BACKGROUND: Tumour-specific radiosensitising treatments may enhance the efficacy of radiotherapy without exacerbating side effects. In this study we determined the radiation response following depletion or inhibition of TOPK, a mitogen-activated protein kinase kinase family Ser/Thr protein kinase that is upregulated in many cancers. METHODS: Radiation response was studied in a wide range of cancer cell lines and normal cells using colony formation assays. The effect on cell cycle progression was assessed and the relationship between TOPK expression and therapeutic efficacy was studied in a cohort of 128 prostate cancer patients treated with radical radiotherapy. RESULTS: TOPK knockdown did not alter radiation response in normal tissues, but significantly enhanced radiosensitivity in cancer cells. This result was recapitulated in TOPK knockout cells and with the TOPK inhibitor, OTS964. TOPK depletion altered the G1/S transition and G2/M arrest in response to radiation. Furthermore, TOPK depletion increased chromosomal aberrations, multinucleation and apoptotic cell death after irradiation. These results suggest a possible role for TOPK in the radiation-induced DNA damage checkpoints. These findings have clinical relevance, as elevated TOPK protein expression was associated with poorer clinical outcomes in prostate cancer patients treated with radical radiotherapy. CONCLUSIONS: This study demonstrates that TOPK disruption may cause tumour-specific radiosensitisation in multiple different tumour types.

OTS964 hydrochloride is an orally active, high affinity and selective TOPK (T-lymphokine-activated killer cell-originated protein kinase) inhibitor with an IC50 of 28 nM. OTS964 hydrochloride is also a potent inhibitor of the cyclin-dependent kinase CDK11, which binds to CDK11B with a Kd of 40 nM.

OTS964,1338545-07-5,Natural Products,Other, buy OTS964 , OTS964 supplier , purchase OTS964 , OTS964 cost , OTS964 manufacturer , order OTS964 , high purity OTS964