Selective Inhibitor Of Nuclear Export Research Articles

Combining Selinexor with R-CHOP in the Treatment of Newly Diagnosed High-Risk (IPI 3-5) GCB Subtype DLBCL Patients: A Multicenter, Open Label Phase 2 Study

Background Diffuse large B-cell lymphoma (DLBCL) is an aggressive and highly heterogeneous lymphoma, and for high-risk group who has an International Prognostic Index (IPI) score of 3-5 it is more difficult to treat (Teras LR,2016; Ziepert M,2010). Under the standard R-CHOP-like immunochemotherapy, the 3-year overall survival (OS) rate of patients with IPI score of 0-1, 2, 3, 4-5 were 91%, 81%, 65% and 59%, respectively (Ziepert M,2010). The efficacy for high-risk population (IPI 3-5) was limited even after intensive chemotherapy, with an ORR of 74.5% and CR of 47.3% under R-CODOX-M/R-IVAC (McMillan AK,2020). Nonetheless, adding new agents to R-CHOP shows better efficacy in patients with IPI 3-5(Tilly H,2022; Nowakowski GS,2021). GCB subtype has better prognosis, but 20% of patients still relapsed after R-CHOP therapy (Nowakowski GS,2015), and no more benefit was achieved by modifying regimen with new agents like polatuzumab-R-CHP (Tilly H,2022), adding on lenalidomide (Nowakowski GS,2015) or ibrutinib (Wilson WH,2021). Selinexor is the only approved oral selective nuclear export inhibitor which demonstrated a 34% ORR in GCB subgroup as a monotherapy in relapsed/refractory DLBCL (Kalakonda N,2020). Selinexor combined with R-CHOP showed a CR rate of 58.8% and ORR of 94.1% in 17 high risk GCB DLBCL patients in a real-world setting (Zhiming Li,2023). This phase 2 study (NCT05422066) further explored the benefit and safety of Selinexor plus R-CHOP in the treatment of newly diagnosed (ND) GCB DLBCL patients with IPI 3-5. Methods This is a multicenter, open label, single arm phase 2 study enrolled 18~75 years old ND GCB DLBCL patients with IPI 3-5. Patients were administered selinexor 60mg QW in combination with standard R-CHOP therapy for 6 cycles (Rituximab 375 mg/m 2, cyclophosphamide 750 mg/m 2, doxorubicin 50 mg/m 2 IV, vincristine 0.5 mg/kg on day 1, prednisone 100 mg PO on days 1-5 in a 21-day cycle). The primary endpoint is complete remission (CR) rate. Secondary endpoints include objective response Rate (ORR), progression free survival (PFS), disease free survival (DFS), overall survival (OS), safety and tolerability. Results The median age of 15 patients was 59 years (range 25-71), with 10 males (66.7%). All patients were in advanced stage according to Ann Arbor staging system, with 13 patients in stage IV, and 2 in stage III. 11(73.3%) patients had ≥2 extranodal lesions and 9 (60%) patients had higher LDH level at baseline. 1 patient had TP53 mutation, and 6 patients (40%) had double expressor lymphoma (DEL) (Table 1). The overall best ORR and CR were 100% and 60%, respectively. The CR rate in 6 DEL patients were 50%; Patients with ≥2 extranodal lesions reached a CR of 54.5% (n=11), while 3 out of 4 patients with≤1 extranodal lesions completely responded. The CR rates of patients with Ki-67≥80% vs＜80% were 50% vs 62.5%, respectively. Median PFS and OS were not reached yet with a median follow-up of 8 months (range 2-11 months). 2 patients had progressive disease with 1 progressed after C4 and the other 1 after C6. 4 patients with viral hepatitis (3 HBV, 1 HCV) were administered both anti-tumor and antiviral therapy, and their HBV-DNA and HCV-RNA levels continuously declined (till undetectable) along with their tumor load (3 CR ,1 PR). Common treatment-relate adverse events (grade 3/4, all grades) included: leukopenia (80%, 93%), neutropenia (73%, 87%), anemia (27%, 93%), thrombocytopenia (27%, 67%), lymphopenia (20%, 27%), anorexia (13%, 40%), pneumonia (13%,40%), hypertriglyceridemia (7%, 40%), diarrhea (7%, 20%). All AEs were managed with appropriate supportive care and dose adjustments. 8 out of 15 patients had a dose reduction of selinexor to 40mg (initial dose 60mg QW) due to AE, 3 in C2 and the other 5 in C4-C5. All patients were continuously treated after dose reduction, and no treatment-related deaths occurred. Overall, 6 patients completed 6 cycles of selinexor+R-CHOP treatment with sustained remission, and 6 patients were still receiving therapy at time of writing this abstract (4 in C6, 2 in C3). 3 patients ended study, 2 PD and 1 withdrew informed consent after PR at the end of C4 (Figure 1). Conclusion Once weekly 60mg selinexor can be safely combined with R-CHOP in ND high risk (IPI 3-5) GCB subtype DLBCL patients with ORR of 100% and CR of 60%. No viral reactivation was observed in patients with viral hepatitis with simultaneous antiviral therapy.

RNA-binding protein hnRNPU regulates multiple myeloma resistance to selinexor

Multiple myeloma (MM) is an incurable haematological cancer. Selinexor is the first-in-class selective inhibitor of nuclear export (SINE) and was newly approved for the treatment of MM. Until now, very few studies have investigated selinexor resistance in MM. Heterogeneous nuclear ribonucleoprotein U (hnRNPU) is an RNA-binding protein and a component of hnRNP complexes. Here we found that hnRNPU regulates MM sensitivity to selinexor. Cell apoptosis assays were performed to compare selinexor-induced cell death in control knockdown (CTR-KD) and hnRNPU knockdown (hnR-KD) MM cells. HnRNPU knockdown-induced nuclear protein retention was examined by proteomics array. HnRNPU-conferred mRNA translation regulation was evaluated by sucrose gradient assay, RNA electrophoresis mobility shift assay, and RNA pull-down assay. We found that hnR-KD MM cells were more sensitive to selinexor-induced cell death in vitro and in mouse model. MM patients who responded to selinexor had relatively low hnRNPU expression. In brief, hnRNPU comprehensively regulated MM sensitivity to selinexor by affecting the localization of LTV1 and NMD3, and mRNA translation of MDM2 and RAN, which were involved in XPO1-mediated nuclear export of ribosome subunits and tumor suppressors. Our discoveries indicate that hnRNPU might be a possible marker to categorize MM patients for the use of Selinexor.

Sequential Administration of Selinexor and CAR-T Therapy in Relapsed/ Refractory Multiple Myeloma

Introduction: Selinexor is a novel, oral selective inhibitor of nuclear export (SINE) that binds to exportin 1 and exhibits anti-tumor activity by impairing nuclear export of proteins including oncogenes and tumor suppressor proteins and is approved for use in patients with relapsed refractory multiple myeloma(RRMM). Anti-BCMA directed CAR-T therapy for patients with relapsed/refractory multiple myeloma (RRMM) is a promising new class of therapy, which has shown a high level of efficacy. Sequential administration of selinexor followed by CD19 CAR-T has shown enhanced efficacy in human phase II trials and animal models of human non-hodgkin lymphoma(Stadel et al., 2022). In this retrospective single institutional study, we report outcomes of patients with RRMM who were treated with Selinexor based regimen prior to apheresis for CAR-T therapy. Methods: We conducted a retrospective study on an IRB-approved protocol for all patients who were treated with Selinexor based regimen immediately prior to apheresis as a prior line of therapy at Hackensack University Medical Center between June 2015 and July 2022. Demographic characteristics, molecular studies, treatment and response information were recorded and included in the study. Response to CAR-T was assessed by the treating physician per International Myeloma Working Group (IMWG) criteria. Survival analysis was performed using the Kaplan-Meier method including PFS and Overall survival (OS). Results: Between September 9, 2021, and April 3, 2023, 7 patients received CAR-T who were treated with Selinexor immediately prior to apheresis. The median age was 65.7 years (range: 55.1-77.1 years). Patients had a median of 6 (range: 4-10) lines of therapy (LOT) prior to CAR-T. 5 out of the 7 patients had double hit myeloma (all 5 with 17p and one other high risk). Four patients were treated with selinexor, carfilzomib and dexamethasone; two patients were treated with selinexor, daratumumab and dexamethasone and one patient was treated with selinexor, pomalidomide and dexamethasone. Four patients received Idecabtagene vicleucel (ide-cel) and three patients received ciltacabtagene autoleucel (cilta-cel). ORR was 100% with all 7 pts achieving very good partial response or better (>=VGPR). 2 patients had bone marrow biopsies that confirmed MRD -ve sCR in both patients. None of the patients have progressed so far, although median follow-up is short at 5.6 months. All patients had hematologic toxicities, 4/7 with grade III anemia (57.1%), 3/7 (42.8%) with grade or higher thrombocytopenia and 4/7 (57.1%) had grade 3 neutropenia. 2 of 7 patients had prolonged cytopenia for >6 months because of pre-existing underlying diagnoses of CCUS and MDS. 5 out of 7 patients had grade 1 Cytokine release syndrome (CRS). The other two patients did not experience CRS. Time of CRS onset was variable 2-10 days. No ICANS or infectious complications were observed. Conclusions: These results suggest that sequential use of Selinexor and CART in high risk RRMM may be an effective treatment strategy to provide deep and durable responses. The findings of our study are promising although it is limited by a small sample size and short follow-up. Further investigation in a larger study and longer follow up would be important to confirm our findings.

Impacting T-cell fitness in multiple myeloma: potential roles for selinexor and XPO1 inhibitors.

Competent T-cells with sufficient levels of fitness combat cancer formation and progression. In multiple myeloma (MM), T-cell exhaustion is caused by several factors including tumor burden, constant immune activation due to chronic disease, age, nutritional status, and certain MM treatments such as alkylating agents and proteasome inhibitors. Many currently used therapies, including bispecific T-cell engagers, anti-CD38 antibodies, proteasome inhibitors, and CART-cells, directly or indirectly depend on the anti-cancer activity of T-cells. Reduced T-cell fitness not only diminishes immune defenses, increasing patient susceptibility to opportunistic infections, but can impact effectiveness MM therapy effectiveness, bringing into focus sequencing strategies that could modulate T-cell fitness and potentially optimize overall benefit and clinical outcomes. Certain targeted agents used to treat MM, such as selective inhibitors of nuclear export (SINE) compounds, have the potential to mitigate T-cell exhaustion. Herein referred to as XPO1 inhibitors, SINE compounds inhibit the nuclear export protein exportin 1 (XPO1), which leads to nuclear retention and activation of tumor suppressor proteins and downregulation of oncoprotein expression. The XPO1 inhibitors selinexor and eltanexor reduced T-cell exhaustion in cell lines and animal models, suggesting their potential role in revitalizating these key effector cells. Additional clinical studies are needed to understand how T-cell fitness is impacted by diseases and therapeutic factors in MM, to potentially facilitate the optimal use of available treatments that depend on, and impact, T-cell function. This review summarizes the importance of T-cell fitness and the potential to optimize treatment using T-cell engaging therapies with a focus on XPO1 inhibitors.

4-Octyl itaconate reduces influenza A replication by targeting the nuclear export protein CRM1.

Itaconate derivates, as well as the naturally produced metabolite, have been proposed as antivirals against influenza virus. Here, the mechanism behind the antiviral effects of exogenous 4-octyl itaconate (4-OI), a derivative of itaconate, against the influenza A virus replication is demonstrated. The data indicate that 4-OI targets the cysteine at position 528 of the CRM1 protein, resulting in inhibition of the nuclear export of viral ribonucleoprotein complexes in a similar manner as previously described for other selective inhibitors of nuclear export. These results postulate a mechanism not observed before for this immuno-metabolite derivative. This knowledge is helpful for the development of derivatives of 4-OI as potential antiviral and anti-inflammatory therapeutics.

Selinexor for the treatment of recurrent or metastatic salivary gland tumors: Results from the GEMS-001 clinical trial.

We aimed to evaluate the activity of selinexor, an oral selective inhibitor of nuclear export, in patients with recurrent or metastatic salivary gland tumors (SGT). GEMS-001 is an open-label Phase 2 study for patients with recurrent or metastatic SGT with two parts. In Part 1 of the protocol, patients had tumor samples profiled with targeted next generation sequencing as well as immunohistochemistry for androgen receptor, HER-2 and ALK. For Part 2, patients with no targeted therapies available were eligible to receive selinexor 60 mg given twice weekly every 28 days. The primary endpoint was objective response rate. Secondary endpoints included progression-free survival (PFS) and prevalence of druggable alterations across SGT. One hundred patients were enrolled in GEMS-001 and underwent genomic and immunohistochemistry profiling. A total of 21 patients who lacked available matched therapies were treated with selinexor. SGT subtypes (WHO classification) included adenoid cystic carcinoma (n = 10), salivary duct carcinoma (n = 3), acinic cell carcinoma (n = 2), myoepithelial carcinoma (n = 2), carcinoma ex pleomorphic adenoma (n = 2) and other (n = 2). Of 18 evaluable patients, stable disease (SD) was observed in 17 patients (94%) (SD ≥6 months in 7 patients (39%)). However, no objective responses were observed. The median PFS was 4.9 months (95% confidence interval, 3.4-10). The most common treatment-related Grade 1-2 adverse events were nausea [17 patients (81%)], fatigue [16 patients (76%)], and dysgeusia [12 patients (57%)]. Most common treatment-related Grade 3-4 adverse events were hyponatremia [3 patients (14%)], neutrophil count decrease [3 patients (14%)] and cataracts [2 patients (10%)]. No treatment-related deaths were observed. Although tumor reduction was observed across participants, single agent selinexor anti-tumor activity was limited.

Discovery of Eriodictyol as Putative Exportin-1 Inhibitor for Non-small Cell Lung Cancer Therapy

Exportin-1, the ubiquitous nuclear protein transporter, is widely confirmed as an active chemotherapeutic target in non-small cell lung cancer conditions, while Juglans mandshurica is a well-studied anticancer plant in some lung cancer cell lines. We intend to find a novel exportin-1 inhibitor from Juglans mandshurica with better potential, tolerability and pharmaco-dynamo-kinetic properties than the current selective inhibitors of nuclear export in non-small cell lung cancer treatment. OSIRIS DataWarrior, along with Glide standard precision docking, and other Glide modules were employed for compound properties exploration, docking simulations, free energy calculations against exportin-1; density functional theory analysis of the compounds were carried out to estimate their electronic stability, while web-based SWISSADME was employed for ADMET and synthetic accessibility evaluations. This study reveals eriodictyol as having higher binding free energy (-40 kcal/mol) than that of standard (-39.56 kcal/mol) in exportin-1 active site, better synthetic accessibility score (3.15 versus 3.29), high GI absorption, non-blood brain barrier permeant, lacks Brenk and PAINS alert, obeying Lipinski’s, Ghose’s, Veber’s, Egan’s, and Muegge’s rule of drug-likeness and lead-likeness as well as non-cytotoxic to HepG2 cells. We therefore found eriodictyol as a lead-like, non-toxic exportin-1 inhibitor with good predictive stability and pharmacokinetic potential and thus provided data for further validation of eriodictyol as a candidate exportin-1 inhibitor in both preclinical and clinical studies involving lung cancer therapy.

LGG-16. NOVEL COMBINATION THERAPIES FOR PEDIATRIC LOW-GRADE GLIOMA AND CHARACTERIZATION OF THE UNDERLYING CELL DEATH MECHANISMS

Abstract BACKGROUND The majority of pediatric low-grade gliomas (pLGGs) harbor a MAPK/ERK pathway overactivating alteration, making them suitable for MAPK-targeted therapies such as MEK inhibition. However, MEK inhibitor treatment alone is in most cases not sufficient to induce complete response, and a rapid rebound of the tumor is the consequence after withdrawal of the therapy. METHODS To identify novel cytotoxic drug combinations, we screened 89 clinically relevant drugs in combination with the MEK inhibitors trametinib and binimetinib. We assessed the regression of cultured 3D microtumors of patient-derived BT40 and BT314 cells, both harboring a BRAFV600E mutation. Depending on the inducible expression of SV40 large T antigen, the BT314 model can reflect two states, proliferation and oncogene-induced senescence. The area of spheroids was measured both in brightfield and with the fluorescent dye TMRE (mitochondrial polarization) at the start and the end of the treatment (6 days). Moreover, metabolic activity was determined through bulk ATP measurement. Drug hit combinations were further analyzed for the successful induction of cell death using high-content microscopy (HCM) imaging and enzymatic caspase activity assays. The microscopic readouts included Hoechst 33342 for the detection of nuclear morphology, BODIPY for sensitizing lipid peroxidation and CM-H2DCFDA as a general oxidative stress indicator. The images were analyzed with the automated image analysis program CellProfiler and the machine learning application CellProfiler Analyst. RESULTS The screening identified the following drug hits: navitoclax (BCL-2 family inhibitor), BRAF inhibitor dabrafenib, mTOR inhibitor everolimus and selinexor, a selective inhibitor of nuclear export. All drugs increased apoptotic cell death and ROS levels at clinically achievable drug concentrations, except the mTOR inhibitors. These results are currently validated in vivo with BT40 zebrafish embryo xenograft models. CONCLUSION Combinations of MEK inhibitors with navitoclax, dabrafenib or selinexor resulted in sufficient apoptosis to induce regression of pLGG microtumors in vitro.

Metronomic dosing of selinexor in select soft tissue sarcomas (STS).

11557 Background: Selinexor (S) is a first-in-class, oral, selective inhibitor of nuclear export (SINE). S has a demonstrated anti-tumor activity in STS. However, the use of S can be associated with toxicities, such as nausea, anorexia and fatigue. A modified dosing schedule may improve the tolerability of S without compromising its efficacy. Methods: We evaluated S when given metronomically in patients (pts) with advanced metastatic leiomyosarcoma, endometrial stromal sarcoma, and malignant peripheral nerve sheath tumors. S was administered daily for 4-days in a row followed by 3-days break, repeated weekly in a 28-days cycle. Dose levels (DL) were escalated using a 3+3 design to determine maximum tolerated dose. DL included 2.5mg (DL1), 5mg (DL2), 7.5mg (DL3), 10 mg (DL4), 12.5 mg (DL5), 15 mg (DL6) and 17.5 mg (DL7). S was administered until unacceptable toxicities or disease progression. Imaging was performed every 8 weeks. Primary objectives were safety and tolerability as well as the determination of the recommended phase II dose. Secondary objectives were anti-tumor activity, toxicity profile, and pharmacokinetics (PK) profile. Results: Twenty-five pts (22 females/3 males, median age 59 years [range 35-84]) were enrolled at different DL (3, 3, 4, 6, 6, 3 pts at DL1 to DL6 respectively). The most common adverse events (AE) of any grade were constipation (n = 11, 50%), nausea (n = 11, 50%), and dysgeusia (n = 10, 45%). Eight (36%) pts experienced G3/4 AE while on trial; most were hematological toxicities seen in 3 (14%) pts (anemia, neutropenia, and leukopenia, n = 1 each). Non-hematological G3/4 AE were seen in 5 (23%) pts (Including: colonic obstruction, atrial fibrillation, and spinal cord compression, n = 1 each). Two Dose limiting toxicities were experienced, at DL4 (thrombocytopenia) and DL5 (transaminitis). Twenty-two pts were evaluable for response; 10 (45%) pts had stable disease (SD) as best response. Eight pts with SD had disease stability of > 4 months. Twelve pts (55%) had progressive disease. Median progression-free survival was 2.4 months (95% CI 1.7-5.3 months). PK data is awaiting final analysis. Conclusions: Metronomic S demonstrated tolerability in selected sarcoma pts. Signs of potential clinical benefit was seen in the form of SD. Further data comparison with historical controls and PK analysis are needed to put this finding into perspective. Clinical trial information: NCT04811196 .

Racial differences in outcomes of patients with relapsed/refractory multiple myeloma treated with selinexor.

e20016 Background: Multiple Myeloma (MM) is the 2nd most common hematologic malignancy in the US, though survival in patients with MM has improved over the past decade. Survival improvements in African Americans (AAs) have been smaller, which may be due to disparity in access to therapies. There are also key differences in MM biology between races, including higher rates of IgA disease and genetics. Given underrepresentation of minorities in clinical trials, we analyzed whether outcomes were similar between AAs and other races in the phase 2 STORM trial (NCT02336815) of selinexor. Selinexor, an oral, first-in-class selective inhibitor of nuclear export via exportin 1, has proven efficacy for refractory MM. To our knowledge, this is the first race subgroup analysis of selinexor in any clinical trial. Methods: Pts from STORM who received study drug (N = 202) were included. Pts with heavily pretreated MM, including triple-class and penta- refractory MM refractory to the last line of therapy were given selinexor (80mg) + dexamethasone (20mg) twice weekly. We conducted a retrospective racial subgroup analysis. Cox proportional modeling was used to determine the hazard ratio (HR) for MM relapse between races controlling for covariates. Results: AAs represented 17% of pts (35 AAs, 148 White, 2 Asian, 11 other and 6 missing). AAs were younger compared to other races (median age 60.7 vs 65.3) with more females (74.3% vs 40.7%). Cytogenetic abnormalities and R-ISS staging were similar between races. AAs had a median progression free survival (PFS) of 6.5 mos (95% CI 4.7, NR) compared with 3.7 mos (95% CI 2.8, 4.6; p = 0.035) for other races. Overall response rate (ORR) was 25.7% (95% CI 12.5, 43.3) in AA pts vs 23.4% [17.2, 30.5] in other races), clinical benefit rate (37.1% [21.5, 55.1] vs 35.9% [28.7, 43.7]), median duration of response (5.6 mos [2.1, NR] vs 5.3 [3.6, NR]), median duration of treatment (9 wks [IQR 3-22 wks] vs 8 wks [4-16 wks]), and mean dose intensity (117.9 mg/wks [STD 35.1] vs 117.1 [34.7]) were similar between grps. Rates of Adverse Events (AEs) ≥ grade 3 (94.3% vs 95.8%), and AE-related dose reductions (45.7% vs 54.5%), discontinuations (22.9% vs 30.5%), and deaths (5.7% vs 10.8%) were also similar. The adjusted HR for MM relapse in AAs was 0.45 (95% CI 0.22, 0.92; p = 0.028) after controlling for gender, age and prior therapy. Conclusions: This subgroup analysis showed that compared with other races, AAs pts were younger and included a greater percentage of women. Although ORRs were similar, AAs had a longer PFS compared with other races after adjusting for covariates. Despite small sample size, the differences were statistically significant. It is unclear if the better PFS reflects a different biology, pharmacology of selinexor or both. Dose adjustments and tolerability were relatively comparable. These results could assist in the placement of selinexor in the treatment sequence of relapsed refractory MM for AAs.

Selinexor and Other Selective Inhibitors of Nuclear Export (SINEs)—A Novel Approach to Target Hematologic Malignancies and Solid Tumors

Exportin 1 (XPO1) is a crucial molecule of nucleocytoplasmic transport. Among others, it exports molecules important for oncogenesis from the nucleus to the cytoplasm. The expression of XPO1 is increased in numerous malignancies, which contributes to the abnormal localization of tumor suppressor proteins in the cytoplasm and subsequent cell cycle dysregulation. Selective inhibitors of nuclear export (SINEs) are novel anticancer agents that target XPO1, arrest tumor suppressor proteins in the nucleus, and induce apoptosis in cancer cells. Selinexor, a first-in-class SINE, has already been approved for the treatment of relapsed/refractory multiple myeloma and relapsed/refractory diffuse large B cell lymphoma not otherwise specified. It has also been proven effective in relapsed/refractory and previously untreated acute myeloid leukemia patients. In addition, numerous studies have yielded promising results in other malignancies of the hematopoietic system and solid tumors. However, future clinical use of selinexor and other SINEs may be hampered by their significant toxicity.

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.

Safety, tolerability, and clinical activity of selinexor in combination with pembrolizumab in treatment of metastatic non-small cell lung cancer.

In lung cancer, overexpression of nuclear export proteins can result in inactivation of critical tumor suppressor proteins and cell-cycle regulators. Selective suppression of nuclear export proteins has immunomodulatory activities. Here, clinical safety and early efficacy data are presented on the combination of pembrolizumab and an oral selective nuclear export inhibitor, selinexor, for the treatment of metastatic non-small cell lung cancer (mNSCLC). The primary objective of this prospective investigator-initiated study was to determine the safety and tolerability of selinexor in combination with pembrolizumab in patients with mNSCLC. Secondary objectives included determination of objective tumor response rate, disease control rate, and progression-free survival duration. A total of 17 patients were included in the final analysis. Fifteen (88%) received more than two lines of prior systemic therapy and 10 (59%) had prior exposure to anti-PD-1/programmed death-ligand 1 (PD-L1) therapy. The median age was 67.5years. Ten patients had grade ≥3 adverse events related to selinexor treatment. Responses to treatment occurred in patients who did and did not undergo previous anti-PD-1/PD-L1 therapy and in patients with activating driver mutations. The median overall survival and progression-free survival were 11.4months (95% CI, 3.4-19.8months) and 3.0months (95% CI, 1.7-5.7months), respectively. The overall response rate was 18% and the 6-month disease control rate was 24%. Selinexor in combination with pembrolizumab demonstrated promising antitumor activity in patients with mNSCLC, including those who had previously received anti-PD-1/PD-L1 therapy. The therapy-related toxic effects were consistent with the prior safety data for both drugs, and no overlapping toxic effects were observed. ClinicalTrials.gov identifier: NCT02419495. New strategies to prevent or reverse resistance to immune checkpoint inhibitors are under investigation. Selective inhibitors of nuclear export proteins, such as selinexor, can induce restoration of tumor-suppressing pathways and induce potent immunomodulatory activities. This article contains the clinical safety and early efficacy data on the combination of pembrolizumab and selinexor in treatment of metastatic non-small cell lung cancer.

Abstract LB299: Identification of key regulators for nuclear protein export inhibitor and chemotherapy combination in pancreatic cancer using spatial genomics approach

Abstract Background: All patients with pancreatic ductal adenocarcinoma (PDAC) experience disease progression after gemcitabine-nab-paclitaxel (GemPac) treatment with a median time to progression of just under 6 months. There is an urgent need for more effective combination therapies for this highly recalcitrant disease. Previously we showed that the selective inhibitor of nuclear export (SINE) selinexor (Sel) against XPO1 in combination with GemPac enhanced the survival of LSL-Kras G12D/+; Trp53 fl/+; Pdx1-Cre (KPC) mice. The Sel-GemPac combination also showed evaluable response in PDAC patients in a Phase I study. Here we identified key regulatory molecules involved in the synergy of the Sel-GemPac combination, utilizing KPC mouse tumors and patient biopsy samples. We also evaluated the efficacy of this combination in a Phase II study. Methods: The activity of Sel-GemPac was evaluated in KPC mouse derived 2D cell line and 3D spheroid models. RNA-seq was performed to evaluate transcriptional differences associated with synergy. The identified differentially expressed genes (DEG) were validated in vitro through siRNA mediated silencing, qPCR, cytotoxicity, and related assays. The molecular mechanism of synergy was also evaluated in KPC mice tumors and in biopsies from patients enrolled in the Phase I portion of the trial using spatial transcriptomic and proteomic analysis. The efficacy of Sel-Gem was evaluated in a Phase II study in patients with metastatic PDAC (NCT02178436). Results: In a KPC tumor derived cell line, Sel inhibited cell growth and suppressed spheroid formation. Sel synergized with GemPac (CI<1) leading to superior inhibition of cell proliferation and suppressed long term growth (colonies). GSEA of RNA-seq showed inhibition of protein transport mechanism after treatment. In spatial transcriptomic analysis, marked suppression of stroma supporting markers were observed in tumor and stromal compartments of KPC tumors. In the treated cancer and stromal cells, 197 and 42 genes were differentially expressed respectively out of a total 11,650 genes, affecting 16 pathways. The top upregulated genes included Mt2, Nrn1, Gpihbp1 and Pals2 and the top downregulated genes include Chil3, Pglyrp1, Ear10 and Prap1. In the Phase II portion of the trial, 4 patients were given Sel (60 mg oral) with Gem (1000 mg/m2 i.v.) on days 1, 8, and 15 of the 28-day cycle. One patient from Phase II showed stable reduction of tumor lesion from 38.3 × 33.2 cm (before) to 33.2 × 26.9 cm (after). The best response based on RECIST 1.1 was minus 25%. This patient had an overall survival of 16 months. In patient biopsies, spatial transcriptomic analysis of malignant ductal tissues, detected 346 and 487 DEG between a responder and a non-responder at baseline, affecting more than 29 pathways. Most important the top DEG included S100P, B2M, CXCL5 and HP. Conclusions: Collectively, our studies show that XPO1 may be a valid therapeutic target in PDAC and Sel-GemPac is a combination warranting further investigation. Citation Format: Md. Hafiz Uddin, Sahar F. Bannoura, Husain Y. Khan, Amro Aboukameel, Yiwei Li, Ibrahim Azar, Eliza W. Bael, Miguel Tobon, Donald Weaver, Steve Kim, Tanya Odisho, Amr Mohammed, Gregory Dyson, Rafic Beydoun, Ramzi M. Mohammad, Herbert Chen, Bassel El-Rayes, Philip A. Philip, Mohammad N. Al-Hallak, Asfar S. Azmi. Identification of key regulators for nuclear protein export inhibitor and chemotherapy combination in pancreatic cancer using spatial genomics approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB299.

Abstract 1652: A novel reversible inhibitor of XPO1 with potent efficacy in multiple preclinical mouse models

Abstract Exportin 1 (XPO1/CRM1) is a key nuclear transport receptor (karyopherin) responsible for the export of different cargo proteins out of the cell’s nucleus into the cytoplasm. Its correct function is essential for cellular homeostasis, however normal XPO1 function is often disrupted in malignant cells. XPO1 is overexpressed in solid and hematological tumors and higher XPO1 expression is often associated with poorer prognosis. XPO1-regulated cargo proteins include tumor suppressor proteins and cell cycle regulators that can be involved in tumorigenesis. For example, aberrant XPO1 function may lead to cytoplasmic mislocalization of tumor suppressor proteins which results in their functional inactivation and hence may cause tumorigenesis. Inhibition of XPO1 function will restore their proper subcellular localization and function and cause tumor regression. Although XPO1 has a central role in cellular homeostasis, it is a good target for cancer therapy, as illustrated by the clinical success of the selective inhibitor of nuclear export (SINE) selinexor. Selinexor is the first and currently the only XPO1 inhibitor clinically approved. It is applied for the treatment of patients with multiple myeloma after at least one prior treatment, and for the treatment of diffuse large B cell lymphoma. Selinexor covalently binds to XPO1. The second generation SINE eltanexor is also a covalent XPO1 inhibitor but has only minimal brain penetration and consequently lower toxicity in preclinical studies. Here, we describe a novel chemical class of reversible XPO1 inhibitors with high brain penetration but with good tolerability allowing frequent dosing in preclinical models. The lead compound, FR-027, potently inhibits XPO1 function (EC50 69 ± 10 nM) and shows potent cancer cell growth inhibition in vitro of both hematological and solid cancer cell lines (EC50 50-950 nM). FR-027 is a reversible inhibitor of XPO1 and unlike many other XPO1 inhibitors it does not induce XPO1 protein degradation; this may contribute to an increased tolerability. Indeed, while it shows high brain penetration, FR-027 allows frequent dosing in mice with good tolerability (body weight). It is orally bioavailable and demonstrates strong anti-leukemic efficacy in an aggressive MOLT-4 xenograft model. Importantly, it shows potent efficacy in both an orthotopic U87 MG brain tumor xenograft model and a metastatic syngeneic ID8-fLuc ovarian cancer model with significant survival benefit as monotherapy. Altogether, these results demonstrate that FR-027 is a novel, reversible XPO1 inhibitor with important molecular and pharmacological characteristics that warrant further clinical development. Citation Format: Janne Van Hauwenhuyse, Felien Reniers, Leentje Persoons, Sam Noppen, Eline Boel, Els Vanstreels, Ann Vankerckhoven, Bert Kwanten, An Coosemans, Guy Van den Mooter, Wim Dehaen, Dirk Daelemans. A novel reversible inhibitor of XPO1 with potent efficacy in multiple preclinical mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1652.

CAR-T cell therapy in multiple myeloma: Current limitations and potential strategies.

Over the last decade, the survival outcome of patients with multiple myeloma (MM) has been substantially improved with the emergence of novel therapeutic agents, such as proteasome inhibitors, immunomodulatory drugs, anti-CD38 monoclonal antibodies, selective inhibitors of nuclear export (SINEs), and T cell redirecting bispecific antibodies. However, MM remains an incurable neoplastic plasma cell disorder, and almost all MM patients inevitably relapse due to drug resistance. Encouragingly, B cell maturation antigen (BCMA)-targeted chimeric antigen receptor T (CAR-T) cell therapy has achieved impressive success in the treatment of relapsed/refractory (R/R) MM and brought new hopes for R/R MM patients in recent years. Due to antigen escape, the poor persistence of CAR-T cells, and the complicated tumor microenvironment, a significant population of MM patients still experience relapse after anti-BCMA CAR-T cell therapy. Additionally, the high manufacturing costs and time-consuming manufacturing processes caused by the personalized manufacturing procedures also limit the broad clinical application of CAR-T cell therapy. Therefore, in this review, we discuss current limitations of CAR-T cell therapy in MM, such as the resistance to CAR-T cell therapy and the limited accessibility of CAR-T cell therapy, and summarize some optimization strategies to overcome these challenges, including optimizing CAR structure, such as utilizing dual-targeted/multi-targeted CAR-T cells and armored CAR-T cells, optimizing manufacturing processes, combing CAR-T cell therapy with existing or emerging therapeutic approaches, and performing subsequent anti-myeloma therapy after CAR-T cell therapy as salvage therapy or maintenance/consolidation therapy.

Prognostic value and therapeutic targeting of XPO1 in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a subtype of B-cell malignancy with high heterogeneity. XPO1 is highly expressed in many hematological malignancies, which predicts poor prognosis. In the study, we aimed to explore the prognostic role of XPO1 and the therapeutic effect of Selinexor, a selective inhibitor of nuclear export, which targets XPO1. We collected 200 CLL samples in our center to confirm XPO1 mRNA expression and analyzed the correlation between XPO1 expression and prognosis. Then, we decreased XPO1 expression with Selinexor to explore the effect of proliferation inhibition, cell cycle arrest, and apoptosis in CLL cell lines. RNA-Seq was performed to explore potential mechanisms. We analyzed XPO1 expression in a cohort of 150 treatment naive patients and another cohort of 50 relapsed and refractory (R/R) patients and found that XPO1 expression was upregulated in 76% of CLL patients compared with healthy donors. Survival analysis suggested that patients with increased XPO1 expression had inferior treatment-free survival (P = 0.022) and overall survival (P = 0.032). The inhibitor of XPO1, Selinexor, induced apoptosis in primary CLL cells. We showed the effects of Selinexor on proliferation inhibition, cell cycle arrest, and apoptosis in CLL cell lines with JVM3, MEC1, and ibrutinib-resistant (MR) cells via nuclear retention of cargo proteins of IκBα, p65, p50, and FOXO3a. Moreover, downregulation of the NF-κB and FOXO pathways was a common feature of the three CLL cell lines responding to Selinexor, indicating the potential application of XPO1 inhibitor even in the high-risk CLL cells. We identified XPO1 as an unfavorable prognostic factor for CLL patients and provided a rationale for further investigation of the clinically XPO1 targeted therapeutic strategy against CLL.

The Latest Research Progress of Selinexor in the Treatment of Non-Hodgkin Lymphoma --Review

Non-Hodgkin lymphoma (NHL) is a common lymphoid hematological malignancy, the treatment and prognosis of NHL have always been the focus of clinical attention. Chemotherapy is the main first-line treatment, but there is still no effective treatment for patients with poor response to chemotherapy, recurrence or progression within a short period of time after treatment, and new and effective drugs need to be developed clinically. As the only clinically validated oral selective inhibitor of nuclear export (SINE), Selinexor has been approved for the treatment of relapsed/refractory diffuse large B-cell lymphoma and multiple myeloma, clinical attempts are being made to apply it to the treatment of other hematological malignancies.This article reviews the anti-tumor mechanism of Selinexor and the latest research progress in its application in NHL, and provides ideas for a more diverse, standardized and effective applications of Selinexor in NHL.

Nuclear Export in Non-Hodgkin Lymphoma and Implications for Targeted XPO1 Inhibitors.

Exportin-1 (XPO1) is a key player in the nuclear export pathway and is overexpressed in almost all cancers. This is especially relevant for non-Hodgkin lymphoma (NHL), where high XPO1 expression is associated with poor prognosis due to its oncogenic role in exporting proteins and RNA that are involved in cancer progression and treatment resistance. Here, we discuss the proteins and RNA transcripts that have been identified as XPO1 cargo in NHL lymphoma including tumour suppressors, immune modulators, and transcription factors, and their implications for oncogenesis. We then highlight the research to date on XPO1 inhibitors such as selinexor and other selective inhibitors of nuclear export (SINEs), which are used to treat some cases of non-Hodgkin lymphoma. In vitro, in vivo, and clinical studies investigating the anti-cancer effects of SINEs from bench to bedside, both as a single agent and in combination, are also reported. Finally, we discuss the limitations of the current research landscape and future directions to better understand and improve the clinical utility of SINE compounds in NHL.

Major clinical research advances in gynecologic cancer in 2022: highlight on late-line PARP inhibitor withdrawal in ovarian cancer, the impact of ARIEL-4, and SOLO-3.

In the 2022 series, we summarized the major clinical research advances in gynecologic oncology based on communications at the conference of Asian Society of Gynecologic Oncology Review Course. The review consisted of 1) Ovarian cancer: long-term follow-up data, new poly (ADP-ribose) polymerase (PARP) inhibitors, overall survival (OS) issues with PARP inhibitor monotherapy, hyperthermic intraperitoneal chemotherapy, immunotherapy, and antibody-drug conjugate; 2) Cervical cancer: surgery in early stage disease, therapy for locally advanced stage and advanced, metastatic, or recurrent setting; and 3) Corpus cancer: follow-up regimen, immune checkpoint inhibitor, WEE1 inhibitor, selective inhibitor of nuclear export. A special note was made on the withdrawal of PARP inhibitor from the market for heavily pretreated ovarian cancer patients based on the final OS results of ARIEL-4 and SOLO-3 due to concerns of increased risk of death.