KPT-330

KPT-330, analog of KPT-185, is a selective inhibitor of CRM1 [1].

Chromosomemaintenance protein 1 (CRM1) is a nuclear export receptor involved in the active transport of transcription factors, cell-cycle regulators, tumor suppressors and RNA molecules. In cancer, CRM1 is overexpression and overactive transport [1].

KPT-330 is an orally bioavailable and selective CRM1 inhibitor. In kidney cancer (RCC) cells, KPT-330 inhibited CRM1 and increased nuclear localization of p21. Then, KPT-330 induced apoptosis and inhibited cells growth [2]. In human non-small cell lung cancer (NSCLC) cells, KPT-330 inhibited cell proliferation and induced the expression of apoptosis-related proteins and cell cycle arrest [3].

In mice bearing MiaPaCa-2 xenograft model, KPT-330 (20 mg/kg) significantly inhibited tumor growth without significant toxicity or body weight loss. Also, KPT-330 increased PAR-4, pro-apoptotic Bax, cleaved PARP and caspase-3. These results suggested that KPT-330 induced apoptosis by the activation of PAR-4 signaling [1]. In mice bearing human NSCLC xenografts, KPT-330 significantly inhibited tumor growth [3].

References:
[1].  Azmi AS, Aboukameel A, Bao B, et al. Selective inhibitors of nuclear export block pancreatic cancer cell proliferation and reduce tumor growth in mice. Gastroenterology, 2013, 144(2): 447-456.
[2].  Wettersten HI, Landesman Y, Friedlander S, et al. Specific inhibition of the nuclear exporter exportin-1 attenuates kidney cancer growth. PLoS One, 2014, 9(12): e113867.
[3].  Sun H, Hattori N, Chien W, et al. KPT-330 has antitumour activity against non-small cell lung cancer. Br J Cancer, 2014, 111(2): 281-291.

Selinexor (KPT-330) Induces Tumor Suppression through Nuclear Sequestration of IkappaB and Downregulation of Survivin.[Pubmed:28314790]

Clin Cancer Res. 2017 Aug 1;23(15):4301-4311.

Purpose: Selinexor, a small molecule that inhibits nuclear export protein XPO1, has demonstrated efficacy in solid tumors and hematologic malignancies with the evidence of clinical activity in sarcoma as a single agent. Treatment options available are very few, and hence the need to identify novel targets and strategic therapies is of utmost importance.Experimental Design: The mechanistic effects of selinexor in sarcomas as a monotherapy and in combination with proteasome inhibitor, carfilzomib, across a panel of cell lines in vitro and few in xenograft mouse models were investigated.Results: Selinexor induced IkappaB nuclear localization as a single agent, and the effect was enhanced by stabilization of IkappaB when pretreated with the proteasome inhibitor carfilzomib. This stabilization and retention of IkappaB in the nucleus resulted in inhibition of NFkappaB and transcriptional suppression of the critical antiapoptotic protein, survivin. Treatment of carfilzomib followed by selinexor caused selinexor-sensitive and selinexor-resistant cell lines to be more sensitive to selinexor as determined by an increase in apoptosis. This was successfully demonstrated in the MPNST xenograft model with enhanced tumor suppression.Conclusions: The subcellular distributions of IkappaB and NFkappaB are indicative of carcinogenesis. Inhibition of XPO1 results in intranuclear retention of IkappaB, which inhibits NFkappaB and thereby provides a novel mechanism for drug therapy in sarcoma. This effect can be further enhanced in relatively selinexor-resistant sarcoma cell lines by pretreatment with the proteasome inhibitor carfilzomib. Because of these results, a human clinical trial with selinexor in combination with a proteasome inhibitor is planned for the treatment of sarcoma. Clin Cancer Res; 23(15); 4301-11. (c)2017 AACR.

KPT-330, a potent and selective exportin-1 (XPO-1) inhibitor, shows antitumor effects modulating the expression of cyclin D1 and survivin [corrected] in prostate cancer models.[Pubmed:26620414]

BMC Cancer. 2015 Dec 1;15:941.

BACKGROUND AND AIMS: Increased expression of Chromosome Region Maintenance (CRM-1)/exportin-1 (XPO-1) has been correlated with poor prognosis in several aggressive tumors, making it an interesting therapeutic target. Selective Inhibitor of Nuclear Export (SINE) compounds bind to XPO-1 and block its ability to export cargo proteins. Here, we investigated the effects of a new class of SINE compounds in models of prostate cancer. MATERIAL AND METHODS: We evaluated the expression of XPO-1 in human prostate cancer tissues and cell lines. Next, six SINE (KPT-127, KPT-185, KPT-205, KPT-225, KPT-251 and KPT-330) compounds having different potency with broad-spectrum, tumor-selective cytotoxicity, tolerability and pharmacokinetic profiles were tested in a panel of prostate cancer cells representing distinct differentiation/progression states of disease and genotypes. Two SINE candidates for clinical trials (KPT-251 and KPT-330) were also tested in vivo in three cell models of aggressive prostate cancer engrafted in male nude mice. RESULTS AND CONCLUSIONS: XPO-1 is overexpressed in prostate cancer compared to normal or hyperplastic tissues. Increased XPO-1 expression, mainly in the nuclear compartment, was associated with increased Gleason score and bone metastatic potential supporting the use of SINEs in advanced prostate cancer. SINE compounds inhibited proliferation and promoted apoptosis of tumor cells, but did not affect immortalized non-transformed prostate epithelial cells. Nuclei from SINE treated cells showed increased protein localization of XPO-1, survivin and cyclin D1 followed by degradation of these proteins leading to cell cycle arrest and apoptosis. Oral administration of KPT-251 and KPT-330 in PC3, DU145 and 22rv1 tumor-bearing nude mice reduced tumor cell proliferation, angiogenesis and induced apoptosis. Our results provide supportive evidence for the therapeutic use of SINE compounds in advanced/castration resistant prostate cancers and warrants further clinical investigation.

Molecular mechanism and therapeutic implications of selinexor (KPT-330) in liposarcoma.[Pubmed:27893412]

Oncotarget. 2017 Jan 31;8(5):7521-7532.

Exportin-1 mediates nuclear export of multiple tumor suppressor and growth regulatory proteins. Aberrant expression of exportin-1 is noted in human malignancies, resulting in cytoplasmic mislocalization of its target proteins. We investigated the efficacy of selinexor against liposarcoma cells both in vitro and in vivo. Exportin-1 was highly expressed in liposarcoma samples and cell lines as determined by immunohistochemistry, western blot, and immunofluorescence assay. Knockdown of endogenous exportin-1 inhibited proliferation of liposarcoma cells. Selinexor also significantly decreased cell proliferation as well as induced cell cycle arrest and apoptosis of liposarcoma cells. The drug also significantly decreased tumor volumes and weights of liposarcoma xenografts. Importantly, selinexor inhibited insulin-like growth factor 1 (IGF1) activation of IGF-1R/AKT pathway through upregulation of insulin-like growth factor binding protein 5 (IGFBP5). Further, overexpression and knockdown experiments showed that IGFBP5 acts as a tumor suppressor and its expression was restored upon selinexor treatment of liposarcoma cells. Selinexor decreased aurora kinase A and B levels in these cells and inhibitors of these kinases suppressed the growth of the liposarcoma cells. Overall, our study showed that selinexor treatment restored tumor suppressive function of IGFBP5 and inhibited aurora kinase A and B in liposarcoma cells supporting the usefulness of selinexor as a potential therapeutic strategy for the treatment of this cancer.