Exercise-Induced Reduction of IGF1R Sumoylation Attenuates Neuroinflammation in APP/PS1 Transgenic Mice

INTRODUCTION

Alzheimer's Disease (AD), a progressive neurodegenerative disorder, is marked by cognitive deterioration and heightened neuroinflammation. The influence of Insulin-like Growth Factor 1 Receptor (IGF1R) and its post-translational modifications, especially sumoylation, is crucial in understanding the progression of AD and exploring novel therapeutic avenues.

OBJECTIVES

This study investigates the impact of exercise on the sumoylation of IGF1R and its role in ameliorating AD symptoms in APP/PS1 mice, with a specific focus on neuroinflammation and innovative therapeutic strategies.

METHODS

APP/PS1 mice were subjected to a regimen of moderate-intensity exercise. The investigation encompassed assessments of cognitive functions, alterations in hippocampal protein expressions, neuroinflammatory markers, and the effects of exercise on IGF1R and SUMO1 nuclear translocation. Additionally, the study evaluated the efficacy of KPT-330, a nuclear export inhibitor, as an alternative to exercise.

RESULTS

Exercise notably enhanced cognitive functions in AD mice, possibly through modulations in hippocampal proteins, including Bcl-2 and BACE1. A decrease in neuroinflammatory markers such as IL-1β, IL-6, and TNF-α was observed, indicative of reduced neuroinflammation. Exercise modulated the nuclear translocation of SUMO1 and IGF1R in the hippocampus, thereby facilitating neuronal regeneration. Mutant IGF1R (MT IGF1R), lacking SUMO1 modification sites, showed reduced SUMOylation, leading to diminished expression of pro-inflammatory cytokines and apoptosis. KPT-330 impeded the formation of the IGF1R/RanBP2/SUMO1 complex, thereby limiting IGF1R nuclear translocation, inflammation, and neuronal apoptosis, while enhancing cognitive functions and neuron proliferation.

CONCLUSION

Moderate-intensity exercise effectively mitigates AD symptoms in mice, primarily by diminishing neuroinflammation, through the reduction of IGF1R Sumoylation. KPT-330, as a potential alternative to physical exercise, enhances the neuroprotective role of IGF1R by inhibiting SUMOylation through targeting XPO1, presenting a promising therapeutic strategy for AD.

Selective nuclear export inhibitor KPT‑330 enhances the radiosensitivity of esophageal carcinoma cells

Although the concurrent application of definitive chemoradiation has improved the prognosis of patients with esophageal cancer, resistance to therapy poses a major threat to treatment. The present study aimed to investigate whether the use of KPT-330, a selective inhibitor of nuclear export (SINE), enhances the radiosensitivity of esophageal cancer cells. Immunohistochemical staining assays were employed to evaluate the expression and prognostic significance of chromosome maintenance protein-1 (CRM1) in 111 esophageal carcinoma (ESCA) tissues collected from patients with esophageal squamous cell carcinoma. The data showed that the expression of CRM1 in the ESCA tissues was significantly upregulated compared with that in the normal adjacent tissues. Furthermore, patients with higher CRM1 expression had significantly decreased overall survival compared with those with lower CRM1 expression. The effects of KPT-330 and/or radiation on ECA109 human ESCA cells were also evaluated. KPT-330 suppressed the viability of the ECA109 cells. A colony formation assay demonstrated that a combination of KPT-330 and radiation significantly decreased ECA109 cell proliferation. Flow cytometric analysis showed that KPT-330 increased the arrest of the ECA109 cells at the G₂/M phase and induced apoptosis. In addition, western blotting revealed that the inhibitory effect of KPT-330 on cell viability was associated with the increased expression of p53 and promotion of the nuclear accumulation of the p53 protein. In conclusion, the present study demonstrated that CRM1 expression is associated with the prognosis of patients with ESCA following radiotherapy. The inhibition of CRM1 expression by the SINE inhibitor KPT-330 increases radiosensitivity and is potentially useful in a combination treatment strategy for esophageal cancers.

KPT-330 and Y219 exert a synergistic antitumor effect in triple-negative breast cancer through inhibiting NF-κB signaling

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype, which has poor prognosis due to the lack of effective targeted drugs. KPT-330, an inhibitor of the nuclear export protein CRM-1, has been widely used in clinical medicine. Y219, a novel proteasome inhibitor designed by our group, shows superior efficacy, reduced toxicity, and reduced off-target effects as compared to the proteasome inhibitor bortezomib. In this study, we investigated the synergistic effect of KPT-330 and Y219 against TNBC cells, as well as the underlying mechanisms. We report that combination treatment with KPT-330 and Y219 synergistically inhibited the viability of TNBC cells in vitro and in vivo. Further analysis revealed that the combined use of KPT-330 and Y219 induced G2-M phase arrest and apoptosis in TNBC cells, and attenuated nuclear factor kappa B (NF-κB) signaling by facilitating nuclear localization of IκB-α. Collectively, these results suggest that the combined use of KPT-330 and Y219 may be an effective therapeutic strategy for the treatment of TNBC.

High Throughput Fluorescence-Based In Vitro Experimental Platform for the Identification of Effective Therapies to Overcome Tumour Microenvironment-Mediated Drug Resistance in AML

The interactions between Acute Myeloid Leukaemia (AML) leukemic stem cells and the bone marrow (BM) microenvironment play a critical role during AML progression and resistance to drug treatments. Therefore, the identification of novel therapies requires drug-screening methods using in vitro co-culture models that closely recreate the cytoprotective BM setting. We have developed a new fluorescence-based in vitro co-culture system scalable to high throughput for measuring the concomitant effect of drugs on AML cells and the cytoprotective BM microenvironment. eGFP-expressing AML cells are co-cultured in direct contact with mCherry-expressing BM stromal cells for the accurate assessment of proliferation, viability, and signaling in both cell types. This model identified several efficacious compounds that overcome BM stroma-mediated drug resistance against daunorubicin, including the chromosome region maintenance 1 (CRM1/XPO1) inhibitor KPT-330. In silico analysis of genes co-expressed with CRM1, combined with in vitro experiments using our new methodology, also indicates that the combination of KPT-330 with the AURKA pharmacological inhibitor alisertib circumvents the cytoprotection of AML cells mediated by the BM stroma. This new experimental model and analysis provide a more precise screening method for developing improved therapeutics targeting AML cells within the cytoprotective BM microenvironment.

Inhibition of XPO1 with KPT-330 induces autophagy-dependent apoptosis in gallbladder cancer by activating the p53/mTOR pathway

BACKGROUND

Gallbladder cancer (GBC) is a highly aggressive malignant cancer in the biliary system with poor prognosis. XPO1 (chromosome region maintenance 1 or CRM1) mediates the nuclear export of several proteins, mainly tumor suppressors. Thus, XPO1 functions as a pro-oncogenic factor. KPT-330 (Selinexor) is a United States Food and Drug Administration approved selective inhibitor of XPO1 that demonstrates good therapeutic effects in hematologic cancers. However, the function of XPO1 and the effect of KPT-330 have not been reported in GBC.

METHODS

We analyzed the correlation between XPO1 expression levels by q-PCR and clinical features of GBC patients. Cell proliferation assays were used to analyze the in vitro antitumor effects of XPO1 inhibitor KPT-330. mRNA sequencing was used to explore the underlying mechanisms. Western blot was performed to explore the relationship between apoptosis and autophagy. The in vivo antitumor effect of KPT-330 was investigated in a nude mouse model of gallbladder cancer.

RESULTS

We found that high expression of XPO1 was related to poor prognosis of GBC patients. We observed that XPO1 inhibitor KPT-330 inhibited the proliferation of GBC cells in vitro. Furthermore, XPO1 inhibitor KPT-330 induced apoptosis by reducing the mitochondrial membrane potential and triggering autophagy in NOZ and GBC-SD cells. Indeed, XPO1 inhibitor KPT-330 led to nuclear accumulation of p53 and activated the p53/mTOR pathway to regulate autophagy-dependent apoptosis. Importantly, KPT-330 suppressed tumor growth with no obvious toxic effects in vivo.

CONCLUSION

XPO1 may be a promising prognostic indicator for GBC, and KPT-330 appears to be a potential drug for treating GBC effectively and safely.

Single cell analysis of PANoptosome cell death complexes through an expansion microscopy method

In response to infection or sterile insults, inflammatory programmed cell death is an essential component of the innate immune response to remove infected or damaged cells. PANoptosis is a unique innate immune inflammatory cell death pathway regulated by multifaceted macromolecular complexes called PANoptosomes, which integrate components from other cell death pathways. Growing evidence shows that PANoptosis can be triggered in many physiological conditions, including viral and bacterial infections, cytokine storms, and cancers. However, PANoptosomes at the single cell level have not yet been fully characterized. Initial investigations have suggested that key pyroptotic, apoptotic, and necroptotic molecules including the inflammasome adaptor protein ASC, apoptotic caspase-8 (CASP8), and necroptotic RIPK3 are conserved components of PANoptosomes. Here, we optimized an immunofluorescence procedure to probe the highly dynamic multiprotein PANoptosome complexes across various innate immune cell death-inducing conditions. We first identified and validated antibodies to stain endogenous mouse ASC, CASP8, and RIPK3, without residual staining in the respective knockout cells. We then assessed the formation of PANoptosomes across innate immune cell death-inducing conditions by monitoring the colocalization of ASC with CASP8 and/or RIPK3. Finally, we established an expansion microscopy procedure using these validated antibodies to image the organization of ASC, CASP8, and RIPK3 within the PANoptosome. This optimized protocol, which can be easily adapted to study other multiprotein complexes and other cell death triggers, provides confirmation of PANoptosome assembly in individual cells and forms the foundation for a deeper molecular understanding of the PANoptosome complex and PANoptosis to facilitate therapeutic targeting.

The efficacy of selinexor (KPT-330), an XPO1 inhibitor, on non-hematologic cancers: a comprehensive review

PURPOSE

Selinexor is a novel XPO1 inhibitor which inhibits the export of tumor suppressor proteins and oncoprotein mRNAs, leading to cell-cycle arrest and apoptosis in cancer cells. While selinexor is currently FDA approved to treat multiple myeloma, compelling preclinical and early clinical studies reveal selinexor's efficacy in treating hematologic and non-hematologic malignancies, including sarcoma, gastric, bladder, prostate, breast, ovarian, skin, lung, and brain cancers. Current reviews of selinexor primarily highlight its use in hematologic malignancies; however, this review seeks to summarize the recent evidence of selinexor treatment in solid tumors.

METHODS

Pertinent literature searches in PubMed and the Karyopharm Therapeutics website for selinexor and non-hematologic malignancies preclinical and clinical trials.

RESULTS

This review provides evidence that selinexor is a promising agent used alone or in combination with other anticancer medications in non-hematologic malignancies.

CONCLUSION

Further clinical investigation of selinexor treatment for solid malignancies is warranted.

Anti-tumor activity of the pan-RAF inhibitor TAK-580 in combination with KPT-330 (selinexor) in multiple myeloma

RAS/RAF/MEK/ERK pathway inhibitors exhibit significant anti-tumor effects against various tumor types, including multiple myeloma (MM), and they are predicted to play a pivotal role in precision medicine. The XPO1 inhibitor KPT-330 has also exhibited promising efficacy in combination with other novel drugs in treating relapsed/refractory MM (RRMM). In this study, we explored the anti-tumor effects of a combination of the pan-RAF inhibitor TAK-580 and KPT-330. Importantly, TAK-580 enhanced KPT-330-induced cytotoxicity and apoptosis in human myeloma cell lines and primary myeloma cells from RRMM patients. Moreover, TAK-580 and KPT-330 synergistically inhibited nuclear phospho-FOXO3a and enhanced cytoplasmic phospho-FOXO3a in MM cells, leading to cytoplasmic enhanced Bim expression and finally apoptosis. This indicates that TAK-580 enhances KPT-330-induced cytotoxicity and apoptosis primarily via the FOXO3a-Bim axis. In addition, TAK-580 enhanced the cytotoxicity of KPT-330 against MM cells even in the presence of IGF-1. Taken together, our results demonstrate that a combination of pan-RAF inhibitor and XPO1 inhibitor is a potential therapeutic option in treating MM.

Identification of nuclear export inhibitor-based combination therapies in preclinical models of triple-negative breast cancer

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High-throughput drug screening reveals promising therapeutic candidates for TNBC.

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KPT-330, an XPO1 inhibitor, and GSK2126458 exhibit synergism in preclinical models of TNBC.

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XPO1 is overexpressed in basal-like breast tumors.

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XPO1 expression is associated with PIK3CA, MTOR, and MKI67 expression at the single-cell level.

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XPO1 overexpression in basal-like patients is associated with greater rates of metastases.

An estimated 284,000 Americans will be diagnosed with breast cancer in 2021. Of these individuals, 15–20% have basal-like triple-negative breast cancer (TNBC), which is known to be highly metastatic. Chemotherapy is standard of care for TNBC patients, but chemoresistance is a common clinical problem. There is currently a lack of alternative, targeted treatment strategies for TNBC; this study sought to identify novel therapeutic combinations to treat basal-like TNBCs. For these studies, four human basal-like TNBC cell lines were utilized to determine the cytotoxicity profile of 1363 clinically-used drugs. Ten promising therapeutic candidates were identified, and synergism studies were performed in vitro. Two drug combinations that included KPT-330, an XPO1 inhibitor, were synergistic in all four cell lines. In vivo testing of four basal-like patient-derived xenografts (PDX) identified one combination, KPT-330 and GSK2126458 (a PI3K/mTOR inhibitor), that decreased tumor burden in mice significantly more than monotherapy with either single agent. Bulk and single-cell RNA-sequencing, immunohistochemistry, and analysis of published genomic datasets found that XPO1 was abundantly expressed in human basal-like TNBC cell lines, PDXs, and patient tumor samples. Within basal-like PDXs, XPO1 overexpression was associated with increased proliferation at the cellular level. Within patient datasets, XPO1 overexpression was correlated with greater rates of metastasis in patients with basal-like tumors. These studies identify a promising potential new combination therapy for patients with basal-like breast cancer.

A phase I trial of selinexor plus FLAG-Ida for the treatment of refractory/relapsed adult acute myeloid leukemia patients

Prognosis for relapsed or refractory (R/R) acute myeloid leukemia (AML) despite salvage therapy is dismal. This phase I dose-escalation trial assessed the safety and preliminary clinical activity of selinexor, an oral exportin-1 (XPO1) inhibitor, in combination with FLAG-Ida in younger R/R AML patients. The aim was to find the recommended phase 2 dose (RP2D) and maximum tolerated dose (MTD). Fourteen patients were included, and selinexor dosage was 60 mg (3 patients), 80 mg (3 patients), and 100 mg (7 patients) weekly. No dose-limiting toxicities were reported. Grade ≥3 non-hematologic adverse events (AEs) occurred in 78.6% of patients. Two patients were non MTD evaluable due to early death, and overall, 3 out of 14 patients (21.4%) had fatal AEs. Five out of 12 (42%) response and MTD evaluable patients achieved a complete remission (CR; n=4) or CR with incomplete hematologic recovery (CRi, n=1), and 4 patients (33%) subsequently underwent allogeneic transplantation. The median overall survival (OS) and event-free survival (EFS) were 6.0 (range 0.9-19.3) and 1.1 months (range 0.7-19.3), respectively. Using selinexor 100 mg/weekly, CR/CRi rate of 66.7%, OS 13.6 months (range, 1.6-19.3), and EFS 10.6 months (range, 0.9-19.3). At last follow-up, 3 patients were alive. Selinexor 100 mg/weekly with FLAG-Ida combination in R/R AML showed acceptable tolerability and efficacy, establishing the RP2D of this regimen in future clinical trials. ClinicalTrials.gov Identifier: NCT03661515.

Selinexor (KPT-330), an Oral Selective Inhibitor of Nuclear Export (SINE) Compound, in Combination with FOLFOX in Patients with Metastatic Colorectal Cancer (mCRC) - Final Results of the Phase I Trial SENTINEL

BACKGROUND

Selinexor is an oral Selective Inhibitor of Nuclear Export compound that specifically blocks Chromosomal Region Maintenance protein 1.

OBJECTIVE

To evaluate the safety and tolerability of escalating doses of selinexor plus 5-fluorouracil, leucovorin and oxaliplatin (mFOLFOX6) in metastatic colorectal cancer (mCRC) patients.

METHODS

In this multicenter phase I trial, mCRC patients, eligible for oxaliplatin-based treatment, were enrolled to receive oral selinexor on days 1, 3, and 8 plus mFOLFOX6 every two weeks. Primary endpoint was the maximum tolerated dose. Secondary endpoints were toxicity, overall response rate, progression free survival, and overall survival.

RESULTS

Overall, 10 patients were enrolled, who had prior treatment with oxaliplatin (6/10), irinotecan (8/10), bevacizumab (6/10) or anti-EGFR therapy (5/10). Four consecutive patients received 40 mg selinexor plus mFOLFOX6. All four experienced dose-limiting toxicities and withdrew from the study after a median of two cycles. Thus, this dose level was regarded as toxic and no further patients were evaluated at this dose. Six patients were enrolled with 20 mg selinexor plus mFOLFOX6. Despite better tolerability, four patients withdrew (patient wish) after the first cycle and only two patients continued until disease progression. Most commonly reported treatment emergent adverse events were nausea (80%), diarrhea (70%), vomiting (60%), fatigue (60%), anorexia (40%), and impaired vision (40%). Due to the short treatment exposure, no relevant clinical activity was observed.

CONCLUSION

In patients with metastatic colorectal cancer, selinexor on this dose schedule plus mFOLFOX6 was not tolerable. Other dosing schedules or combinations may be evaluated. Clinical trial identifier NCT02384850.

Selinexor (KTP-330) - a selective inhibitor of nuclear export (SINE): anti-tumor activity in diffuse large B-cell lymphoma (DLBCL)

Introduction: Selinexor is a first-in-class, oral therapeutic that selectively inhibits nuclear export. It has received fast track designation from the FDA for the treatment of relapsed or refractory diffuse large B-cell lymphoma (DLBCL) recently, and continues to be evaluated as a potential treatment for DLBCL.Area covered: This article reviews the available data from clinical trials regarding the efficacy of selinexor in DLBCL and highlights the key toxicity issues and how they may best be managed. Ongoing and future studies in DLBCL are also discussed.Expert opinion: More translational studies are necessary to leverage the unique mechanism action and rationally inform the use of selinexor in combination strategies. There are several different genetic subtypes of DLBCL, but it is not clear if these classifications will identify patients that may benefit from targeted therapies. The broad potential mechanism of action of selinexor will require careful analysis to inform predictive or prognostic biomarkers. Further evaluation of selinexor in combination with standard lymphoma regimens could identify deliverable promising regimens. Future randomized trials are key for registration and to determine the optimal role for this first-in-class agent.

Association of XPO1 Overexpression with NF-κB and Ki67 in Colorectal Cancer

OBJECTIVES

Exportin 1(XPO1), a nuclear exporter protein, has been gaining recognition in cancer progression and treatment. This study aimed to evaluate the association between the overexpression of XPO1 with NF-κB, Ki67 and clinicopathological characteristics in colorectal cancer (CRC) tissue samples and to explore the anti-proliferative effect of KPT-330, as XPO1 inhibitor, in colorectal cancer cell line.

METHODS

Forty CRC tissue samples were analyzed by immunostaining for the expressions of XPO1, NF-κB and Ki67 and then the anti-proliferative effect of the KPT-330 was also evaluated in HT29 colorectal cancer cell line.

RESULTS

XPO1 overexpression was observed in 52.5% of CRC and significantly apparent with strong intensity in tumor cells compared to the normal adjacent epithelium (P<0.001). Regarding to the histopathological characteristics, the XPO1 overexpression significantly associated with advanced tumor stages (P=0.049) and has great tendency towards moderate/poorly differentiated tumors. Although the XPO1 overexpression was strongly associated with high Ki67 expression (P=0.001), only Ki67 expression showed significant association with tumor size (P=0.012). No significant association was detected between the XPO1 overexpression and NF-κB, while the NF-κB positive expression was significantly associated with lymph node metastasis and Ki67 expression at P=0.027 and P= 0.007, respectively. The in vitro experiments showed a great impact of KPT-330, as XPO1 inhibitor, to inhibit cancer growth in dose and time dependent manner and significantly diminished the colony formation (P<0.001) of HT29 cells- associated with the expression of Ki67 (P<0.001).

CONCLUSION

XPO1 overexpression and NF-κB expression may serve as potential biomarker associated with CRC pathogenesis and proliferation, while the KPT-330 is effectively inhibited-colon cancer growth in vitro. Further studies considering the prognostication role of XPO1 overexpression in CRC are required.
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Expression, function, and targeting of the nuclear exporter chromosome region maintenance 1 (CRM1) protein

Nucleocytoplasmic trafficking of proteins/RNAs is essential to normal cellular function. Indeed, accumulating evidence suggests that cancer cells escape anti-neoplastic mechanisms and benefit from pro-survival signals via the dysregulation of this system. The nuclear exporter chromosome region maintenance 1 (CRM1) protein is the only protein in the karyopherin-β protein family that contributes to the trafficking of numerous proteins and RNAs from the nucleus. It is considered to be an oncogenic, anti-apoptotic protein in transformed cells, since it reportedly functions as a gatekeeper for cell survival, including affecting p53 function, and ribosomal biogenesis. Furthermore, abnormally high expression of CRM1 is correlated with poor patient prognosis in various malignancies. Therapeutic targeting of CRM1 has emerged as a novel cancer treatment strategy, starting with a clinical trial with leptomycin B, the original specific inhibitor of CRM1, followed by development of several next-generation small molecules. KPT-330, a novel member of the CRM1-selective inhibitors of nuclear export (SINE) class of compounds, is currently undergoing clinical evaluation for the therapy of various malignancies. Results from these trials suggest that SINE compounds may be particularly useful against hematological malignancies, which often become refractory to standard chemotherapeutic agents.

Selective inhibitors of nuclear export (SINE) in hematological malignancies

Regulated nucleo-cytoplasmic transport plays a major role in maintaining cellular homeostasis. CRM1 (chromosome region maintenance 1 or exportin 1 or XPO 1) is responsible for the nucleo-cytoplasmic transport of more than 200 proteins, including most of the tumor suppressor proteins (TSP). CRM1 is overexpressed in pancreatic cancer, osteosarcoma, glioma, cervical and hematological malignancies. This inspired the development of novel agents that selectively inhibit nuclear exportins (SINEs). In this review we focus on the significance of CRM1 in carcinogenesis and review the new development of SINE inhibitiors in hematological malignancies. Selinexor (KPT-330) as the first-in-human SINE agent represents this novel class of anti-cancer agents.