Karyopherin beta 1 (Kpnb1) is a nuclear transport receptor that imports cargoes into the nucleus. Recently, elevated Kpnb1 expression was found in certain cancers and Kpnb1 silencing with siRNA was shown to induce cancer cell death. This study aimed to identify novel small molecule inhibitors of Kpnb1, and determine their anticancer activity. An in silico screen identified molecules that potentially bind Kpnb1 and Inhibitor of Nuclear Import-43, INI-43

The Karyopherin superfamily is a major class of soluble transport receptors consisting of both import and export proteins. The trafficking of proteins involved in transcription, cell signalling and cell cycle regulation among other functions across the nuclear membrane is essential for normal cellular functioning. However, in cancer cells, the altered expression or localization of nuclear transporters as well as the disruption of endogenous nuclear transport inhibitors are some ways in which the Karyopherin proteins are dysregulated. The value of nuclear transporters in the diagnosis, prognosis and treatment of cancer is currently being elucidated with recent studies highlighting their potential as biomarkers and therapeutic targets. V C 2016 IUBMB Life, 68(4): [268][269][270][271][272][273][274][275][276][277][278][279][280] 2016

Context Poor uterine receptivity is one major factor leading to pregnancy loss and infertility. Understanding the molecular events governing successful implantation is hence critical in combating infertility. Objective To define Progesterone Receptor (PGR)-regulated molecular mechanisms and epithelial roles in receptivity. Design RNA-sequencing and PGR-ChIP-seq were conducted in parallel to identify PGR-regulated pathways during the Window of implantation (WOI) in endometrium of fertile women. Setting Endometrial biopsies from the proliferative and mid-secretory phases were analyzed. Patients or Other Participants Participants were fertile, reproductive aged (18–37 years) women with normal cycle length, and without any history of dysmenorrhea, infertility, or irregular cycles. In total, 42 endometrial biopsies obtained from 42 women were analyzed in this study. Interventions There were no interventions during this study. Main Outcome Measures Here we measured the alterations in gene expression and PGR occupancy in the genome during the WOI, based on the hypothesis that PGR binds uterine chromatin cycle dependently to regulate genes involved in uterine cell differentiation and function. Results 653 genes were identified with regulated PGR binding and differential expression during the WOI. These were involved in regulating inflammatory response, xenobiotic metabolism, epithelial mesenchymal transition, cell death, interleukin/Signal Transducer And Activator Of Transcription (STAT) signaling, estrogen response, and Mammalian target of rapamycin complex 1 (MTORC1) response. Transcriptome of the epithelium identified 3052 differentially expressed genes, of which 658 were uniquely regulated. Transcription factors Interferon Regulatory Factor 8 (IRF8) and Myocyte Enhancer Factor 2C (MEF2C) were found to be regulated in the epithelium during the WOI at the protein level, suggesting potentially important functions that are previously unrecognized. Conclusion PGR binds the genomic regions of genes regulating critical processes in uterine receptivity and function.

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Background Inhibition of nuclear import via Karyopherin beta 1 (Kpnβ1) shows potential as an anti-cancer approach. This study investigated the use of nuclear import inhibitor, INI-43, in combination with cisplatin. Methods Cervical cancer cells were pre-treated with INI-43 before treatment with cisplatin, and MTT cell viability and apoptosis assays performed. Activity and localisation of p53 and NFκB was determined after co-treatment of cells. Results Pre-treatment of cervical cancer cells with INI-43 at sublethal concentrations enhanced cisplatin sensitivity, evident through decreased cell viability and enhanced apoptosis. Kpnβ1 knock-down cells similarly displayed increased sensitivity to cisplatin. Combination index determination using the Chou-Talalay method revealed that INI-43 and cisplatin engaged in synergistic interactions. p53 was found to be involved in the cell death response to combination treatment as its inhibition abolished the enhanced cell death observed. INI-43 pre-treatment resulted in moderately stabilized p53 and induced p53 reporter activity, which translated to increased p21 and decreased Mcl-1 upon cisplatin combination treatment. Furthermore, cisplatin treatment led to nuclear import of NFκB, which was diminished upon pre-treatment with INI-43. NFκB reporter activity and expression of NFκB transcriptional targets, cyclin D1, c-Myc and XIAP, showed decreased levels after combination treatment compared to single cisplatin treatment and this associated with enhanced DNA damage. Conclusions Taken together, this study shows that INI-43 pre-treatment significantly enhances cisplatin sensitivity in cervical cancer cells, mediated through stabilization of p53 and decreased nuclear import of NFκB. Hence this study suggests the possible synergistic use of nuclear import inhibition and cisplatin to treat cervical cancer.

BackgroundKaryopherin β1 (Kpnβ1) is the main nuclear import protein involved in the transport of cargoes from the cytoplasm into the cell nucleus. Previous research has found Kpnβ1 to be significantly overexpressed in cervical cancer and other cancer tissues, and further studies showed that inhibition of Kpnβ1 expression by siRNA resulted in cancer cell death, while non-cancer cells were minimally affected. These results suggest that Kpnβ1 has potential as an anticancer therapeutic target, thus warranting further research into the association between Kpnβ1 expression and cancer progression. Here, the biological effects associated with Kpnβ1 overexpression were investigated in order to further elucidate the relationship between Kpnβ1 and the cancer phenotype.MethodsTo evaluate the effect of Kpnβ1 overexpression on cell biology, cell proliferation, cell cycle, cell morphology and cell adhesion assays were performed. To determine whether Kpnβ1 overexpression influences cell sensitivity to chemotherapeutic agents like Cisplatin, cell viability assays were performed. Expression levels of key proteins were analysed by Western blot analysis.ResultsOur data revealed that Kpnβ1 overexpression, above that which was already detected in cancer cells, resulted in reduced proliferation of cervical cancer cells. Likewise, normal epithelial cells showed reduced proliferation after Kpnβ1 overxpression. Reduced cancer cell proliferation was associated with a delay in cell cycle progression, as well as changes in the morphology and adhesion properties of cells. Additionally, Kpnβ1 overexpressing HeLa cells exhibited increased sensitivity to cisplatin, as shown by decreased cell viability and increased apoptosis, where p53 and p21 inhibition reduced and enhanced cell sensitivity to Cisplatin, respectively.ConclusionsOverall, our results suggest that a tight balance of Kpnβ1 expression is required for cellular function, and that perturbation of this balance results in negative effects associated with a variety of biological processes.Electronic supplementary materialThe online version of this article (10.1186/s12885-018-5044-8) contains supplementary material, which is available to authorized users.

21WNK1 is critical for uterine function as a mediator of stromal cell decidualization in vitro. 22 Here, we employed a mouse model with conditional WNK1 ablation from the female 23 reproductive tract to define its in vivo role in uterine biology. Loss of WNK1 altered uterine 24 morphology, causing endometrial epithelial hyperplasia, adenomyosis and a delay in 25 embryo implantation, ultimately resulting in compromised fertility. Mechanistic 26 investigations through transcriptomic and proteomic approaches uncovered the 27 regulatory role of WNK1 in controlling the PP2A-AKT-FOXO1 signaling axis. We show 28 that WNK1 interacts directly with PPP2R1A, which is crucial for PP2A phosphatase 29 activity. PP2A phosphatase in turn dephosphorylates AKT, thereby reducing its inhibitory 30 effect on FOXO1. This permits the nuclear entry of FOXO1 to transcriptionally regulate 31 implantation-associated genes. Our findings revealed a novel function of WNK1 in 32 regulating AKT-FOXO1 post-translational modification, and demonstrated that this 33 signaling pathway is critical in normal uterine physiology and pregnancy. 34 35 36 37 38 physiological functions, the underlying cellular components regulated by WNK1 may share 62 similarity between the different tissues. 63 64Despite its ubiquitous expression pattern, WNK1's role in organs other than those described 65 above remain unexplored. Given the role of WNK1 in regulating uterine stromal cell biology in 66 vitro, we hypothesized that WNK1 is essential in regulating uterine functions. To test this idea, we 67 established a conditional uterine WNK1 ablated mouse model, which resulted in severely 68 compromised fertility. We demonstrated that WNK1 is critical in maintaining uterine morphology, 69regulating epithelial proliferation and permitting appropriate embryo implantation. Additionally, we 70 defined the molecular mechanism through both transcriptomic and proteomic approaches to show 71 that the WNK1 signaling cascade begins by its direct interaction with the scaffold subunit of the 72 phosphatase complex PP2A, PPP2R1A. This interaction stabilized PP2A which prevented 73 unregulated AKT phosphorylation, ultimately alleviating AKT's inhibitory effect on FOXO1 nuclear 74 localization, an indispensable mediator of implantation 16 . 75 76 5 RESULTS 77 78 WNK1 is expressed in the uterus during early pregnancy in both humans and mice 79WNK1 expression was examined by immunohistochemistry in human endometrium during the 80 proliferative and mid-secretory phases as well as in the peri-implantation uterus of mice. In 81 humans, WNK1 is expressed in both the epithelial and stromal cells during the proliferative and 82 mid-secretory phases (Fig. 1.A). Similarly in mice, WNK1 is expressed during and after 83 implantation on gestation days (GDs) 4.5 and 5.5 (Fig. 1.B). These findings support the in vivo 84 involvement of WNK1 in regulating functions of the female reproductive tract. 85 86 WNK1 ablation altered uterine morphology and microenvironment 87To examine WNK1's function in the ...

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