Proteasome Inhibitors Carfilzomib Research Articles

A Novel Patient-Derived Xenograft Model of Secondary CD20- CNS Lymphoma for Mechanistic and Therapeutic Exploration

IntroductionThe majority of secondary central nervous system (CNS) lymphoma cases are derived from histologically high-grade systemic lymphomas such as diffuse-large B cell lymphoma (DLBCL) and Burkitt's lymphoma. These CNS lymphomas are associated with poor prognosis and a low likelihood of long-term survival, especially rituximab-ineffective CD20- lymphoma. To investigate the biological features and potential therapeutic targets of CNS-involved CD20- lymphoma, we established the first known patient-derived xenograft (PDX) model using cerebrospinal fluid (CSF).MethodsSix- to 8-week-old male NSG mice (Jackson Laboratory) were housed and monitored in our animal research facility. All experimental procedures and protocols were approved by the Institutional Animal Care and Use Committee of The University of Texas MD Anderson Cancer Center. A total of 0.08 million cells were isolated from 2 mL of CSF obtained from a CD20- CD79A- DLBCL patient with Bcl-2 and Myc rearrangements (double-hit). The isolated cells were directly injected into a human fetal bone chip implanted into NSG (NSG-hu) mice. After passage, the mice were administered several small molecules, and tumor burden was measured via tumor volume and human β2M levels over the course of treatment. Kaplan-Meier survival analysis was also performed. PDX tissue was collected for histological analysis, immunophenotyping, genotyping, and proteomics analysis.ResultsThe PDX tumors possessed the same histological, genetic and immunophenotypical features as the primary patient tumor cells. The PDXs had Bcl-2 and Myc rearrangements and were positive for CD10, CD19, CD22, and CD45 and were negative for CD5, CD20, and CD79A. After tumor passage, the mice were treated with vehicle, 50 mg/kg ibrutinib (Bruton's tyrosine kinase (BTK) inhibitor) oral gavage daily, 50 mg/kg ABT199 (Bcl-2 inhibitor) oral gavage daily, 1 mg/kg carfilzomib (proteasome inhibitor) i.v. twice per week, or 7.5 mg/kg IACS-010759 (oxidative phosphorylation (OXPHOS) inhibitor) oral gavage daily. As shown in Figure 1, the PDX tumor was resistant to the BTK inhibitor ibrutinib and moderately responsive to the proteasome inhibitor carfilzomib. Although the Bcl-2 gene was rearranged, the PDX model only had a partial response to the Bcl-2 inhibitor ABT-199 (ABT-199 vs control, p = 0.0004). In contrast, inhibition of the OXPHOS pathway with IACS-010759 significantly inhibited 96% tumor growth (IACS-010759 vs control, p < 0.00001) and prolonged mouse survival by approximately 25 days compared with the vehicle control and the other drugs (IACS-010759 vs control, ABT-199, or ibrutinib, p < 0.0001). Moreover, proteomics analysis demonstrated that IACS-010759 not only inhibited OXPHOS but also upregulated the pro-apoptotic protein Bim.ConclusionTo our knowledge, this is the first PDX model generated from the CSF of a CD20- double-hit DLBCL patient. With this PDX model, we determined that the OXPHOS inhibitor IACS-010759 is a promising therapeutic agent for this aggressive cancer. [Display omitted] DisclosuresWang:Acerta Pharma: Honoraria, Research Funding; Kite Pharma: Research Funding; Novartis: Research Funding; Pharmacyclics: Honoraria, Research Funding; Dava Oncology: Honoraria; Juno: Research Funding; MoreHealth: Consultancy; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Carfilzomib-Based Regimens Are Efficacious and Well Tolerated in Heavily Pre-Treated Multiple Myeloma Patients: Real World Data from a Norwegian Cohort

IntroductionMultiple myeloma (MM) is considered an incurable disease. However, during the last years the survival has improved, partly due to the development of new drugs. The second-generation proteasome inhibitor Carfilzomib (Kyprolis®) was first approved for marketing in Norway in January 2016. Carfilzomib in combination with Dexamethasone (Kd) for patients with relapsing and/or refractory multiple myeloma (RRMM) was approved for reimbursement in August 2017, while the combination with Lenalidomide (Revlimid®) and Dexamethasone (KRd) is still not reimbursed in Norway. Both regimens now have mature and beneficial survival data (vs Vd and Rd, respectively). In the period before market approval, Carfilzomib was provided through a named patient program (NPP) for patients who had a critical disease with few treatments options. This abstract presents results from this cohort.AimIn this retrospective study all 33 Norwegian MM patients who received Carfilzomib through a named patient program (NPP) during the period of March 2014 to January 2016, were included. The aim was to describe the patients 'characteristics and their treatment responses, in addition to use the real-life experience to highlight a possible benefit of making new drugs available before marketing approval. During this study period, neither Daratumumab, Ixazomib nor Elotuzumab were available in Norway. The medical records were printed and sent from 10 different hospitals to Oslo Myeloma Center. Baseline values and treatment responses was assessed and entered into our myeloma database. Statistical analysis was done to determine response rates and time to event outcomes.ResultsThe participants had received a median of 6 (1-11) previous lines of therapy, including bortezomib (100%), and thalidomide and/or lenalidomide (97%) before inclusion in this study Among these, 64 % or 66 % respectively was refractory to the indicated treatment. 76 % of the study participants had received at least one ASCT. Median time from diagnosis to initiating carfilzomib treatment was 5 years (0-15) for the 32 patients who received carfilzomib. Patients who received the triplet treatment KRd, had a benefit in terms of response with ORR of 19%, compared to 8 %for patients receiving Kd/K (p=0, 04). CBR for these patients was 22 % and 25 %, respectively (p=0,33). There was no difference between the two groups for PFS or OS, with a median OS of 10 months (0-24) for patients receiving KRd compared to 9 month (2-14) for Kd/K. However, patients receiving KRd showed a trend towards a better PFS compared to Kd with a median PFS of 3,5 months (1,4 - 4,6) compared to 2,5 months (0,2 - 3,8) (p=0,095).Adverse events occurred in 91 % of the patients where 41 %, 31 % and 41 % respectively experienced a Grade 3 or higher for anemia, neutropenia or thrombocytopenia (according to CTCAE vs 4.0). 19 % experienced cardiovascular complications and 3% ended treatment due to them. Of these patients, 50 % had received doxorubicin at a previous treatment line and 17% received doxorubicin in combination with Carfilzomib. Overall, 9% of the patients discontinued the treatment due to adverse events while 6 % died before the end of the treatment. Carfilzomib was not considered a direct cause of death in any of these patients. At the end of the study (January 2018), 76 % of the participants were dead.ConclusionIn this real-life study, RRMM patients who received lenalidomide in addition to carfilzomib and dexametason showed a superior response in comparison with patients who received carfilzomib and dexamethasone with an ORR of 19 % versus 8 %. There was no significant overall survival benefit, but a trend towards a better PFS for KRd compared to Kd/K. As an overall conclusion, this group of highly treated MM patients had a benefit from receiving Carfilzomib in combination with lenalidomide before marketing approval. DisclosuresSchjesvold:Oncopeptides: Consultancy; Novartis: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Adaptive: Consultancy; Bayer: Consultancy; Bristol Myers Squibb: Consultancy; Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Abbvie: Honoraria.

Interim Results of the Observational Study Caro: Twice Weekly Carfilzomib Is a Convenient Treatment Option for Patients with Multiple Myeloma Who Have Received at Least One Prior Therapy

Introduction:Poor adherence and persistence to anticancer treatment are serious issues in the management of cancer patients since nonadherence has been shown to lead to higher treatment failure rates, worse outcome and higher total costs of care. The combination of the proteasome inhibitor carfilzomib (Kyprolis®) with lenalidomide (Revlimid®) and dexamethasone (CAR/LEN/DEX) or with dexamethasone alone (CAR/DEX) is approved for the treatment of patients with multiple myeloma who have received at least one prior therapy. According to the current approved schedule, carfilzomib has to be given twice weekly in both regimens. Real-world data on the implementation of this treatment recommendation are still limited.Methods:The prospective, multicenter, non-interventional, observational CARO study was designed to collect data on 300 patients with multiple myeloma (CAR/LEN/DEX: 200, CAR/DEX: 100) from 90 sites across Germany. Primary objective is patients' adherence and persistence to carfilzomib therapy as prescribed by the treating physician according to current Summary of Product Characteristics (SmPC). Secondary objectives are patients' adherence and persistence to lenalidomide and dexamethasone as well as the real-world implementation of the recommended CAR/LEN/DEX or CAR/DEX dosing regimen in clinical routine (i.e., the comparison of actually administered medication versus recommended medication according to current SmPC). Exploratory objectives are effectiveness, safety and health-related quality of life. The first interim analysis of the CARO study was scheduled to assess the primary and secondary endpoints 12 months after the recruitment of the first patient.Results:Between October 2016 and October 2017, 102 patients had been enrolled, thereof 68 patients into the CAR/LEN/DEX cohort and 32 patients into the CAR/DEX cohort at the time of the pre-specified interim analysis (database cut: 25 October 2017).Here, the focus is on the adherence of the twice weekly carfilzomib schedule in evaluable patients who received CAR/LEN/DEX (N=64) and on the implementation of the SmPC in terms of timing, dosing and frequency. Median age of patients was 72.3 years (range 43.4-84.3), 45.3% were female and 70.3% of the patients had a good performance status (PS) with a Karnofsky PS score of 80 to 100. The relative mean dose intensity of carfilzomib was 88.1%. 1368 of the scheduled 1591 carfilzomib administrations (86.0%) were given in time. 7.9% (n=125) of administrations were omitted, 5.0% (n=80) of administrations were delayed and 1.1% (n=18) of doses were administered earlier. Carfilzomib was omitted at least once in 43.8% of patients (n=28). 62.5% (n=40) and 18.8% (n=12) of patients, respectively, had a delayed or earlier carfilzomib administration documented at least once during their course of treatment. Reasons for deviations from the recommended carfilzomib dosing schedule concerning timing are depicted in Table 1. 1328 of 1466 carfilzomib administrations (90.6%) were given at the recommended dose. 6.2% (n=91) of doses were reduced. The main reason for dose reduction was the occurrence of adverse events (4.0%, n=58). Other reasons were: nonadherence (1.2%, n=18), organizational reasons (0.1%, n=2) and others (0.9%, n=13). 23.4% (n=15) of patients received at least one reduced carfilzomib dose during their course of treatment.The mean adherence to the carfilzomib dosing regimen (i.e., the percentage of doses administered as scheduled by the treating physician and not modified for adherence reasons) was 94.8%.Conclusion:According to our interim results, 86% of carfilzomib administrations were given in time and more than 90% of administrations were given at the recommended dose. Deviations from the recommended carfilzomib regimen were mainly due to safety issues or organizational reasons, but not due to nonadherence. Carfilzomib treatment adherence was almost 95%. Though, despite the required twice weekly dosing schedule, the carfilzomib regimen seems to be a convenient treatment option for multiple myeloma patients. Results have to be confirmed at final analysis. DisclosuresKnauf:Celgene: Consultancy, Honoraria; Roche: Consultancy; Amgen: Consultancy, Honoraria; Mundipharma: Consultancy; Gilead Sciences: Consultancy; AbbVie: Consultancy; Janssen: Consultancy. Marschner:Amgen: Consultancy, Honoraria; IOMEDICO: Employment, Equity Ownership; Sandoz: Honoraria.

Predicting Carfilzomib Resistance Mechanisms and Therapeutics Using Computational Modelling of Genomics and Proteomics

Background: Multiple myeloma (MM) is a malignancy of plasma cells accounting for around 10% of all hematologic cancers. MM is an incurable heterogeneous malignancy which impacts the response rate due to complex nature of the disease. Although with standard of care treatment, including proteasome inhibitors (PI), a significant response and remission is achieved, the majority of patients still develops resistance. There is no precise method for determining the pathways which govern the acquired resistance to PI. Computational biology modelling (CBM), which uses genomics for creating the MM specific disease characteristics, can be used for deciphering the dominance of signaling changes in acquired resistance and accordingly select right treatment combination. Predicting a priori treatment response based on disease characteristics would enable optimal treatment selection and potentially reduce the trial and error approach that impacts outcome and health care costs.Aim: The objective of the study was to predict response to proteasome inhibitor Carfilzomib (CFZ) in AMO1 MM disease model and its resistant counterparts using CBM, to determine mechanism of resistance to CFZ and identify customized therapy options for CFZ resistant AMO1 (AMO-CFZ) cells.Methods: AMO-CFZ resistant cells were derived by long-term exposure of the cells to increasing doses of CFZ. AMO1 PI-sensitive and AMO-CFZ were analyzed using cytogenetics and mutations (profiled by next-generation sequencing; NGS). At the same time quantitative proteomic analysis was done to find proteins which were upregulated as well as downregulated in the resistant cells. Genomic and proteomic data was input to generate disease-specific protein network maps, biomarkers and pathway characteristics unique to AMO1 and AMO-CFZ cells respectively. Digital drug models of CFZ and other targeted-FDA approved drugs are simulated on the disease models individually and in combination at varying doses. Drug impact was assessed by quantitatively measuring the effect on a cell growth score, which is a composite of cell proliferation, viability and apoptosis. Unique therapy combinations identified in AMO-CFZ cells will be prospectively experimentally validated; at the same time key signaling changes were deciphered in AMO-CFZ resistance with respect to AMO1 PI-sensitive MM model.Results: Genomic analysis using CBM showed that AMO1 MM model harbored amplification of MYC, POU2AF1, POU2F1, TXNIP and knock down (KD) of proteasome subunit PSMA6 which lead to Carfilzomib sensitivity. The predictions in AMO-CFZ identified loss of PSMA6 and upregulation of proteasomal subunits PSMB5/7/2/1 which reduced ER stress and ATF4. Predictions in AMO-CFZ cells identified higher glycolysis and pentose phosphate pathway resulting in higher glutathione levels compared to AMO1 PI-sensitive cells. The anti-oxidant proteins NQO1, TXN, PRDX1/4/5 were higher in AMO-CFZ-resistant cells, in addition to PRDX6 overexpression (OE), which was common with PI-sensitive cells that reduced oxidative stress. Carfilzomib drug exporter ABCB1 was overexpressed in CFZ-resistant cells and Nelfinavir increased sensitivity of the cells towards Carfilzomib. CBM identified novel therapeutic targets CDK5 and NFE2L2 that can be used to overcome CFZ-resistance. Moreover, Venetoclax was more cytotoxic in AMO-CFZ cells than in AMO-1 PI-sensitive, because BCL2 was higher in CFZ-resistant version than the sensitive one due to its overexpression and TP53 knockdown.CBM predicted novel therapeutics for investigation which include: GEMCITABINE plus MELPHALAN; GEMCITABINE plus OLAPARIB; MELPHALAN plus OLAPARIB. DNA damage is high in AMO-CFZ due to knockdown of CHEK1, ERCC3, FANCB/G, LIG4, XRCC6 and loss of function of FANCD2, ATM.Conclusions: Using genomics and proteomics, CBM identified the resistance mechanisms of AMO-CFZ and new treatment strategies. These were validated showcasing a methodology for a clinically relevant workflow using NGS information. DisclosuresCogle:Celgene: Other: Steering Committee Member of Connect MDS/AML Registry. Vali:Cell Works Group Inc.: Employment. Abbasi:Cell Works Group Inc.: Employment. Singh:Cellworks Research India Private Limited: Employment. Gupta:Cellworks Research India Private Limited: Employment. Kushwaha:Cellworks Research India Private Limited: Employment. Kumari:Cellworks Research India Private Limited: Employment. Raju:Cellworks Research India Private Limited: Employment. Naga:Cellworks Research India Private Limited: Employment. Basu:Cellworks Research India Private Limited: Employment.

Proteasome Inhibition By Carfilzomib Impairs Terminal Erythroid Maturation and Causes Reticulocytosis in Patients with Multiple Myeloma

IntroductionThe ubiquitin-proteasome system (UPS) is crucial for cellular protein homeostasis by ensuring the degradation of redundant or misfolded proteins. As a result, the UPS plays a key role in the regulation of multiple cellular processes, including erythropoiesis, where the proteasome is essential for erythroid expansion and differentiation. The UPS is also of major importance in terminal maturation to erythrocytes, by regulating the degradation of ribosomal proteins (Nguyen et al, Science 2017). Proteasome inhibition is a cornerstone of multiple myeloma (MM) treatment. At present, the reversible proteasome inhibitors (PI) bortezomib, ixazomib and irreversible PI carfilzomib have been approved for clinical use in MM. Based on an internal clinical observation of increased reticulocyte counts in patients with MM under treatment with carfilzomib, we hypothesized that PI can affect erythroid maturation. For this purpose, we measured reticulocyte counts in patients treated with different PI and performed in vitro erythroid differentiation and maturation studies in the presence of PI.Materials and methodsWe first retrospectively assessed the effect of carfilzomib treatment on the red cell parameters in 40 patients treated with a carfilzomib-based regimen (carfilzomib-dexamethasone (Kd) or carfilzomib-lenalidomide-dexamethasone (KRd)). Data were compared to matched cohorts of patients treated with bortezomib and the immunomodulatory drug (IMiD) lenalidomide. To assess the effect of PI on erythroid differentiation in vitro, we differentiated CD34+ hematopoietic progenitor cells (HPC) from healthy individuals into erythroid cells using an adaptation of the protocol described by the Douay group (Nature Biotechnology, 2002). To evaluate the effect of PI on terminal erythroid maturation, reticulocytes, isolated from the peripheral blood of healthy volunteers, were differentiated to mature erythrocytes in vitro. For this purpose, we established an optimized reticulocyte purification protocol by combining Percoll gradient centrifugation and magnetic-activated cell sorting (MACS), yielding a reticulocyte population with > 90% purity, as assessed by brilliant Cresyl blue and thiazole orange staining. During in vitro maturation, reticulocytes were exposed to different proteasome inhibitors, including carfilzomib, bortezomib, ixazomib and MG-132 at increasing concentrations and during different time intervals.ResultsWe found that treatment with carfilzomib resulted in a marked elevation of reticulocyte counts from the second treatment cycle onwards. This effect was highly significant (p<0.001), both compared to baseline levels and to reticulocyte counts during treatment with bortezomib or lenalidomide. However, hemoglobin levels remained unaffected over the course of treatment (p = 0.32), and signs of hemolysis were absent (Fig. 1.a,b). Subsequent in vitro experiments demonstrated that both long-term (continuous) and short-term (1 hour) exposure to carfilzomib significantly impairs the terminal maturation of purified reticulocytes toward mature erythrocytes (p<0.01). This same effect could only be observed with reversible PI during continuous, but not during short-term exposure (Fig. 1.c). Finally, carfilzomib did not alter the proportion of mature erythroid cells that were produced in vitro during differentiation experiments starting from CD34+ HPCs. These results support our initial hypothesis of impaired terminal erythroid maturation during treatment with carfilzomib. To further unravel the mechanisms how carfilzomib affects terminal erythroid maturation, quantitative proteomics analysis using liquid chromatography-mass spectrometry (LC-MS/MS) analysis is ongoing.ConclusionOur results indicate that proteasome inhibition with carfilzomib causes a delay of terminal erythroid maturation, which is independent of erythroid commitment, expansion and differentiation. In combination with the clinical findings, our results provide a novel explanation for reticulocytosis during treatment with carfilzomib. Moreover, we believe our optimized purification protocol has the potential to facilitate future research on reticulocytes. [Display omitted] DisclosuresDelforge:Celgene and Janssen: Research Funding; Amgen, Celgene, Janssen and Takeda: Consultancy.

A Phase 2 Study of Carfilzomib Plus Elotuzumab Plus Dexamethasone for Myeloma Patients Relapsed after 1-3 Prior Treatment Lines

Introduction: The median progression free survival (PFS) and overall survival (OS) of multiple myeloma (MM) patients have been prolonged due to novel agents combined with ASCT but the median OS in MM is still 7-8 years. Thus, the feasibility of new combinations and dosing of available agents must be investigated. The first proteasome inhibitor (PI), bortezomib (B), combined with elotuzumab and dexamethasone (d) showed superiority to Bd with PFS of 9.7 vs. 6.9 months, respectively, without excessive toxicity (Jakubowiak et al. Blood 2016;127:2833-40).In our study we investigate the safety, feasibility and initial efficacy of a second generation PI carfilzomib (K), SLAMF7 antibody elotuzumab (E) and dexamethasone (D) combination (KED) in relapsed or refractory MM (RRMM) patients.Patients and methods: Forty RRMM patients after 1-3 prior lines will be included in this phase 2 study after written informed consent. The primary endpoint is overall response rate (ORR). In patients achieving at least very good partial remission (VGPR) the quality of response will be assessed with high-sensitivity multicolour flow cytometry (MFC) according to the 8-colour EuroFlow protocol. Carfilzomib is given once weekly 20 mg/m2 on D1C1 and thereafter 70 mg/m2 in 28 day cycles on days 1, 8 and 15 in cycles 1-8 and on days 1 and 15 thereafter combined with weekly elotuzumab 10 mg/kg on days 1, 8 and 15 in cycles 1-2, thereafter on days 1 and 15; dexamethasone 40 mg on days 1, 8, 15 and 22 on cycles 1-8, thereafter on days 1 and 15. Treatment will continue until progression or excessive toxicity. Carfilzomib dose was 20/56 mg/m2 for the first two cycles for the first five patients to evaluate the safety. Additionally, patient samples collected prior to treatment will be comprehensively profiled by whole exome and RNA sequencing and evaluated for ex vivo response to the agents. Together, the study addresses clinical response, ex vivo-in vivo translation, identifies molecular biomarkers for the KED combination and facilitates precision guided clinical trials for RRMM.Results: By the end of July 2018, 11 patients have been enrolled. Median number of prior lines was 2 (1-3). Seven IgG-κ, two IgA-κ and one kappa and lambda light-chain patient are included. After a median of 6 (2-12) cycles ORR is 91% with 3 patients in VGPR (median MFC-MRD of 0,002%), 7 patients in PR, one in MR. Initial molecular characterization highlighted diverse subclonal backgrounds among the treated patients (Figure 1), but interestingly, the best responding VGPR patients displayed mutations to RAS genes in the dominant clones (NRAS 828, 2662; KRAS 733). At least PR was achieved after a median of 1 (1-4) cycle. Three patients have progressed and one patient withdrawn due to suspected thrombotic microangiopathy with manifestation of convulsions and pulmonary embolism. We noticed only one grade 2 infusion reaction after premedication. One patient developed autoimmune hemolytic anemia (AIHA), without red cell antibodies, suspected to be related to elotuzumab. She recovered with steroids and elotuzumab discontinuation and continued Kd without reappearance of AIHA. Another patient had grade 3 liver transaminase elevation but was able to continue treatment with dose reduction of carfilzomib and dexamethasone.Conclusion: To the best of our knowledge this is the first study evaluating the carfilzomib, elotuzumab and dexamethasone combination in RRMM with comprehensive molecular annotations. Among this small group of patients we noticed two unexpected severe adverse events; atypical AIHA and suspected thrombotic microangiopathy. AIHA should be excluded if unexpected anemia will appear during elotuzumab treatment. Preliminary results of this KED combination showed efficacy in patients with clonal RAS mutations and ORR of 91% after the median of two prior treatment lines using weekly carfilzomib dose of 70 mg/m2.Figure 1: Subclonal diversity in patient derived plasma cells. Clonal and subclonal fractions were evaluated by assessing peaks of variant allele frequencies of somatic mutations present in the myeloma plasma cells using kernel density estimation. For each plot, the fraction of cells carrying the mutation is represented on the x axis (1 = 100% of cells), and the probability density on the y axis. The mutated cell fraction (x axis) was calculated by adjusting mutant allele burden by copy number of the mutated loci. [Display omitted] DisclosuresSilvennoinen:Takeda: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Tsallos:Novartis: Research Funding. Anttila:Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees. Räsänen:Amgen: Honoraria. Luoma:Amgen: Honoraria. Jantunen:Amgen: Honoraria; Genzyme/Sanofi: Honoraria; Takeda: Honoraria. Heckman:Celgene: Research Funding; Orion Pharma: Research Funding; Novartis: Research Funding.

Carfilzomib-Lenalidomide-Dexamethasone (KRd) Induction-Autologous Transplant (ASCT)-Krd Consolidation Vs KRd 12 Cycles Vs Carfilzomib-Cyclophosphamide-Dexamethasone (KCd) Induction-ASCT-KCd Consolidation: Analysis of the Randomized Forte Trial in Newly Diagnosed Multiple Myeloma (NDMM)

Background: Proteasome inhibitor (PI)-based induction and consolidation proved to be effective in newly diagnosed multiple myeloma (NDMM) patients (pts) eligible for melphalan 200 mg/m2-autologous stem cell transplant (MEL200-ASCT). High response rates have been reported with the second-generation PI Carfilzomib in combination with Lenalidomide-dexamethasone (KRd) or Cyclophosphamide-dexamethasone (KCd). Aims: The primary aim was to evaluate the efficacy and safety of KRd induction-ASCT-KRd consolidation (KRd-ASCT-KRd) vs 12 cycles of KRd (KRd12) vs KCd induction-ASCT-KCd consolidation (KCd-ASCT-KCd). Methods: NDMM pts ≤65 years were randomized (1:1:1; stratification ISS and age) to: KRd-ASCT-KRd: 4 28-day cycles with KRd induction (Carfilzomib 20/36 mg/m2 IV days 1,2,8,9,15,16; Lenalidomide 25 mg days 1-21; dexamethasone 20 mg days 1,2,8,9,15,16) followed by MEL200-ASCT and 4 KRd consolidation cycles; KRd12: 12 KRd cycles; KCd-ASCT-KCd: 4 28-day induction cycles with KCd (Carfilzomib 20/36 mg/m2 IV days 1,2,8,9,15,16; Cyclophosphamide 300 mg/m2 days 1,8,15; dexamethasone 20 mg days 1,2,8,9,15,16) followed by MEL200-ASCT and 4 KCd consolidation cycles. Thereafter, pts were randomized to maintenance with Lenalidomide alone or plus Carfilzomib. Centralized minimal residual disease (MRD) evaluation - 8-color second generation flow cytometry, sensitivity 10-5 - was performed in pts achieving ≥very good partial response (VGPR). Endpoints were pre-maintenance stringent complete response (sCR) and MRD negativity in intention-to-treat (ITT) analysis. Data cut-off was May 30, 2018. Results: 474 NDMM pts were randomized (KRd-ASCT-KRd, n=158; KRd12, n=157; KCd-ASCT-KCd, n=159) and analyzed. Pts characteristics were well balanced. Median follow-up was 20 months. Depth of response improved during treatment (Figure). By ITT analysis, rates of pre-maintenance sCR was similar between KRd-ASCT-KRd (41%) and KRd12 (42%), and significantly higher than with KCd-ASCT-KCd (30%; P value KRd-ASCT-KRd vs KCd-ASCT-KCd=0.047; P value KRd12 vs KCd-ASCT-KCd=0.028). Similarly, rate of ≥CR was 49% with KRd-ASCT-KRd, 52% with KRd12 and 38% with KCd-ASCT-KCd (P value KRd-ASCT-KRd vs KCd-ASCT-KCd=0.041; P value KRd12 vs KCd-ASCT-KCd=0.014) and rate of ≥CR+unconfirmed CR (missing immunofixation confirmation) raised to 60% vs 63% vs 46% in the 3 groups, respectively; rate of ≥VGPR was 88% with KRd-ASCT-KRd, 86% with KRd12 and 74% with KCd-ASCT-KCd (P value KRd-ASCT-KRd vs KCd-ASCT-KCd=0.002; P value KRd12 vs KCd-ASCT-KCd=0.008). In multivariate analysis, the main factor affecting probability of achieving ≥VGPR, ≥CR or sCR was treatment with KRd-ASCT-KRd or KRd12 vs KCd, with no significant impact of ISS Stage or FISH abnormalities. In ITT analysis (MRD missing [31/395 VGPR pts, 8%] and Conclusions: Rates of MRD negativity, sCR, ≥CR, ≥VGPR were significantly higher with KRd-ASCT-KRd and KRd12 vs KCd. At present, no differences in MRD and overall best response (sCR, ≥CR, ≥VGPR) were noticed between KRd-ASCT-KRd and KRd12; longer follow-up is needed to evaluate survival. Treatment was well tolerated. Updated data will be presented at the meeting. Disclosures Gay:Roche: Other: Advisory Board; Seattle Genetics: Other: Advisory Board; Bristol-Myers Squibb: Honoraria; Janssen: Honoraria; Celgene: Honoraria, Other: Advisory Board; Amgen: Honoraria; Takeda: Honoraria, Other: Advisory Board. Galli:Sigma-Tau: Honoraria; Janssen: Honoraria; Celgene: Honoraria; Bristol-Myers Squibb: Honoraria. Belotti:Celgene: Other: Advisory Board; Amgen: Other: Advisory Board. Zamagni:BMS: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity9s Board of Directors or advisory committees. Angelucci:Novartis: Honoraria, Other: Chair Steering Committee TELESTO protocol in MDS; Celgene: Honoraria, Other: Chair DMC proptocol BELIEVE 1 and BELIVE 2 in Thalassemia; Vertex Pharmaceuticals Incorporated (MA) and CRISPR Therapeutics AG (CH): Other: Chair DMC CRISPR CAS9 in Hemoglobinopathies; Jazz Pharmaceuticals Italy: Other: Local (national) advisory board on AML; Roche Italia: Other: Local (national) advisory board on biosimilars. Annibali:Celgene; Takeda; Amgen, Janssen Cilag: Honoraria. Offidani:Amgen: Honoraria, Other: Advisory Board; Takeda: Honoraria, Other: Advisory Board; Janssen: Honoraria, Other: Advisory Board; Celgene: Honoraria, Other: Advisory Board; Bristol-Myers Squibb: Honoraria, Other: Advisory Board. Palumbo:Takeda: Employment. Musto:Amgen: Honoraria; BMS: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Celgene: Honoraria. Cavo:GlaxoSmithKline: Honoraria, Membership on an entity9s Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Honoraria, Membership on an entity9s Board of Directors or advisory committees. Boccadoro:Bristol-Myers Squibb: Honoraria, Research Funding; Mundipharma: Research Funding; Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; AbbVie: Honoraria.

Role of Osteocytes in Myeloma Bone Disease: Anti-sclerostin Antibody as New Therapeutic Strategy.

Osteocytes are terminally differentiated cells of the osteoblast lineage. They are involved in the regulation of bone remodeling by increasing osteoclast formation or decreasing bone formation by the secretion of the osteoblast inhibitor sclerostin. Monoclonal antibody anti-sclerostin, Romosozumab, has been developed and tested in clinical trials in patients with osteoporosis. In the last years, the role of osteocytes in the development of osteolytic bone lesions that occurs in multiple myeloma, have been underlined. Myeloma cells increase osteocyte death through the up-regulation of both apoptosis and autophagy that, in turn, triggers osteoclast formation, and activity. When compared to healthy controls, myeloma patients with bone disease have higher osteocyte cell death, but the treatment with proteasome inhibitor bortezomib has been shown to maintain osteocyte viability. In preclinical mouse models of multiple myeloma, treatment with blocking anti-sclerostin antibody increased osteoblast numbers and bone formation rate reducing osteolytic bone lesions. Moreover, the combination of anti-sclerostin antibody and the osteoclast inhibitor zoledronic acid increased bone mass and fracture resistance synergistically. However, anti-sclerostin antibody did not affect tumor burden in vivo or the efficacy of anti-myeloma drugs in vitro. Nevertheless, the combination therapy of anti-sclerostin antibody and the proteasome inhibitor carfilzomib, displayed potent anti-myeloma activity as well as positive effects on bone disease in vivo. In conclusion, all these data suggest that osteocytes are involved in myeloma bone disease and may be considered a novel target for the use of antibody-mediated anti-sclerostin therapy also in multiple myeloma patients.

Irreversible proteasome inhibition with carfilzomib as first line therapy in patients with newly diagnosed multiple myeloma: Early in vivo cardiovascular effects

Patients who experienced cardiovascular side effects during cancer therapy with carfilzomib for multiple myeloma had relapsed multiple myeloma, so have be previously treated with other cancer therapies. The present is a single center cohort study to evaluate early cardiovascular effects of administration of irreversible proteasome inhibitor carfilzomib in naïve patients. We included 24 patients and collected cardiovascular side effects, echocardiographic parameters and endothelial function at baseline and after 4 cycles. At early follow up we observed increase in blood arterial pressure values (mean change in systolic pressure of 10 mmHg (P-value < 0.01; diastolic arterial pressure and mean arterial pressure of 3.3 mmHg and 5.4 mmHg, both P-value < 0.01). Reactive hyperemia PAT index was reduced in the whole cohort by a mean of 0.46 points (P-value < 0.01); diastolic function was changed: E-wave-deceleration-time (EDT) was reduced by 49,96 ± 31 ms, P-value < 0.05 and early diastolic tissue Doppler velocity (e′) by a mean value of 1.46 cm/s, P - value 0.04.At early follow up we did not observe events of grade 3 or 4. We observe correlation between events and endothelial dysfunction at baseline and age (OR 1.9, CI 95% 0.05–5.804, P- value: 0.038 for RHI<1.67; OR 1,4, CI 95%0.99–2.56, P- value: 0.04 for age). Our results suggest that therapy with carfilzomib when used as first line therapy is responsible for increase in systemic blood pressure, alteration of endothelium-mediated vascular dilatation and early myocardial diastolic dysfunction.

Spectrum and functional validation of PSMB5 mutations in multiple myeloma.

Despite an increasing number of approved therapies, multiple myeloma (MM) remains an incurable disease and only a small number of patients achieve prolonged disease control. Some genes have been linked with response to commonly used anti-MM compounds, including immunomodulators (IMiDs) and proteasome inhibitors (PIs). In this manuscript, we demonstrate an increased incidence of acquired proteasomal subunit mutations in relapsed MM compared to newly diagnosed disease, underpinning a potential role of point mutations in the clonal evolution of MM. Furthermore, we are first to present and functionally characterize four somatic PSMB5 mutations from primary MM cells identified in a patient under prolonged proteasome inhibition, with three of them affecting the PI-binding pocket S1. We confirm resistance induction through missense mutations not only to Bortezomib, but also, in variable extent, to the next-generation PIs Carfilzomib and Ixazomib. In addition, a negative impact on the proteasome activity is assessed, providing a potential explanation for later therapy-induced eradication of the affected tumor subclones in this patient.

Pre-clinical evaluation of proteasome inhibitors for canine and human osteosarcoma.

Osteosarcoma, a common malignancy in large dog breeds, typically metastasises from long bones to lungs and is usually fatal within 1 to 2 years of diagnosis. Better therapies are needed for canine patients and their human counterparts, a third of whom die within 5 years of diagnosis. We compared the in vitro sensitivity of canine osteosarcoma cells derived from 4 tumours to the currently used chemotherapy drugs doxorubicin and carboplatin, and 4 new anti-cancer drugs. Agents targeting histone deacetylases or PARP were ineffective. Two of the 4 cell lines were somewhat sensitive to the BH3-mimetic navitoclax. The proteasome inhibitor bortezomib potently induced caspase-dependent apoptosis, at concentrations substantially lower than levels detected in the bones and lungs of treated rodents. Co-treatment with bortezomib and either doxorubicin or carboplatin was more toxic to canine osteosarcoma cells than each agent alone. Newer proteasome inhibitors carfilzomib, ixazomib, oprozomib and delanzomib manifested similar activities to bortezomib. Human osteosarcoma cells were as sensitive to bortezomib as the canine cells, but slightly less sensitive to the newer drugs. Human osteoblasts were less sensitive to proteasome inhibition than osteosarcoma cells, but physiologically relevant concentrations were toxic. Such toxicity, if replicated in vivo, may impair bone growth and strength in adolescent human osteosarcoma patients, but may be tolerated by canine patients, which are usually diagnosed later in life. Proteasome inhibitors such as bortezomib may be useful for treating canine osteosarcoma, and ultimately may improve outcomes for human patients if their osteoblasts survive exposure in vivo, or if osteoblast toxicity can be managed.

Ancient drug curcumin impedes 26S proteasome activity by direct inhibition of dual-specificity tyrosine-regulated kinase 2

Curcumin, the active ingredient in Curcuma longa, has been in medicinal use since ancient times. However, the therapeutic targets and signaling cascades modulated by curcumin have been enigmatic despite extensive research. Here we identify dual-specificity tyrosine-regulated kinase 2 (DYRK2), a positive regulator of the 26S proteasome, as a direct target of curcumin. Curcumin occupies the ATP-binding pocket of DYRK2 in the cocrystal structure, and it potently and specifically inhibits DYRK2 over 139 other kinases tested in vitro. As a result, curcumin diminishes DYRK2-mediated 26S proteasome phosphorylation in cells, leading to reduced proteasome activity and impaired cell proliferation. Interestingly, curcumin synergizes with the therapeutic proteasome inhibitor carfilzomib to induce apoptosis in a variety of proteasome-addicted cancer cells, while this drug combination exhibits modest to no cytotoxicity to noncancerous cells. In a breast cancer xenograft model, curcumin treatment significantly reduces tumor burden in immunocompromised mice, showing a similar antitumor effect as CRISPR/Cas9-mediated DYRK2 depletion. These results reveal an unexpected role of curcumin in DYRK2-proteasome inhibition and provide a proof-of-concept that pharmacological manipulation of proteasome regulators may offer new opportunities for anticancer treatment.

Abstract LB-269: IDH2 inhibition enhances proteasome inhibitor responsiveness in hematological malignancies

Abstract The introduction of proteasome inhibitors (PIs) into the clinic has transformed the treatment of patients affected by multiple myeloma (MM) and mantle-cell lymphoma (MCL) establishing new standards of care. Despite these improvements, patients continuously relapse or are intrinsically resistant to PIs. Here, to identify druggable targets that synergize with PIs, we carried out a functional screening in MM cell lines using a short hairpin RNA library targeting 152 cancer driver genes, highly representative of all signaling pathways. The Isocitrate Dehydrogenase 2 (IDH2) gene was identified as a top candidate, showing a synthetic lethal activity with the PI Carfilzomib (CFZ). IDH2 is a NADP(+) dependent mitochondrial enzyme which catalyzes the oxidative decarboxylation of isocitrate to 2-oxoglutarate in the tricarboxylic acid (TCA) cycle. We demonstrated that combinations of the pharmacological IDH2 inhibitor AGI-6780 with FDA approved PIs significantly increased apoptotic cell death in ten MM cell lines, both sensitive and resistant to PIs. Combined treatments triggered synergistic cytotoxicity also in four MCL and in two Burkitt's lymphoma cell lines. Importantly, CFZ/AGI-6780 treatment increased death of primary CD138-positive cells from nine MM patients and exhibited a favorable cytotoxicity profile towards peripheral blood mononucleated cells and bone marrow-derived stromal cells. Mechanistically, CFZ/AGI-6780 combination significantly decreased TCA cycle activity and ATP levels, as a consequence of enhanced IDH2 enzymatic inhibition. In contrast, only a slight increase of mitochondrial reactive oxygen species (ROS) was observed. CFZ treatment reduced the expression of nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting enzyme required for IDH2 activation through the NAD(+)-dependent deacetylase SIRT3. Consistently, combination of CFZ with either NAMPT (FK866) or SIRT3 (AGK7) inhibitors impaired IDH2 activity and increased MM cell death, thus phenocopying CFZ/AGI-6780 effects and putting the proteasome in a direct link with IDH2 inhibition. Finally, inducible IDH2 knock-down enhanced the therapeutic efficacy of CFZ in a subcutaneous xenograft model of MM, resulting in inhibition of tumor progression and extended survival. In conclusion, our data demonstrate that IDH2 inhibition increases the therapeutic efficacy of PIs, thus providing compelling evidence for treatments with lower and less toxic doses, and broadening the application of PIs to other malignancies. Citation Format: Elisa Bergaggio, Chiara Riganti, Giulia Garaffo, Elisabetta Mereu, Nicoletta Vitale, Cecilia Bandini, Elisa Pellegrino, Paola Omedè, Katia Todoerti, Valentina Audrito, Antonio Rossi, Francesco Bertoni, Silvia Deaglio, Antonino Neri, Antonio Palumbo, Roberto Piva. IDH2 inhibition enhances proteasome inhibitor responsiveness in hematological malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-269.

Abstract 884: Mechanistically-driven investigation of pegcrisantaspase combination therapy against acute myeloid leukemia

Abstract Introduction: Novel, more efficacious, and better tolerated therapy for acute myeloid leukemia (AML) is needed, as current treatment options result in only 35-40% 5 year survival in patients younger than 60 years of age. Targeting cellular metabolism, specifically by disrupting glutamine metabolism, is a promising approach to treat AML since altering metabolism appears to affect AML cell growth more compared to normal cells. L-asparaginases, which are approved for use in acute lymphoblastic leukemia, has been shown to alter glutamine metabolism in AML cells. In a recently published clinical trial, we found that Erwinaze, Erwina chrysanthemi asparaginase, is capable of depletion of plasma glutamine levels and is well tolerated in adult patients with AML with no occurrence of dose-limiting toxicity (DLT). Here, we report the anti-AML activity of pegcrisantaspase, a novel long-acting Erwinia chrysanthemi L-asparaginase, in combination with clinically relevant chemotherapeutic agents in vitro and in vivo. Materials and Methods: In this study we investigated the cytotoxic effect of pegcrisantaspase along with 12 other clinically relevant chemotherapeutic agents. In vitro anti-proliferative activity of each agent was determined in 7 different AML cell lines (MV4-11, MOLM-14, MonoMac-6, U937, THP-1, HL60, K562) using the WST-1 cell proliferation reagent. In combination studies, cell survival was measured by Trypan blue staining. For determination of synergism, results of the WST-1 cell proliferation assay were analyzed by median effect analysis and used to determine a combination index (CI), with synergism defined as CI values &amp;lt;0.9. In vivo anti-AML activity of pegcrisantaspase was determined in NSG mice harboring luciferase, expressing the MV4-11 cell line. Results: Pegcrisantaspase inhibited AML cell growth in six of seven cell lines tested, with IC50s ranging from 0.0001 IU/mL to 0.049 IU/mL. At higher concentrations, pegcrisantaspase was synergistic with the proteasome inhibitors ixazomib and carfilzomib. When pegcrisantaspase was combined with the Bcl-2 inhibitor, venetoclax, pegcrisantaspase potentiated the effect of venetoclax in AML cells by more than 10 fold. Additionally, pegcrisantaspase showed significant anti-AML effects compared to control in our mouse xenograft model. Conclusions and Future Directions: Our data demonstrates the meaningful anti-AML activity of pegcrisantaspase in vitro and in vivo. The results also suggest that combination of pegcrisantaspase with proteasome and Bcl-2 inhibitors is potentially efficacious at treating AML. Mechanistic experiments to examine the phosphorylation state of key downstream targets of mTOR are ongoing. Furthermore, future in vivo studies will involve combining the above chemotherapies with pegcrisantaspase in our mouse xenograft model. Citation Format: Hannah Kaizer, Binny Bhandary, Brandon A. Carter-Cooper, Eun Yong Choi, Bandish Kapadia, Elizabeth T. Chang, Rena G. Lapidus, Ronald B. Gartenhaus, Ashkan Emadi. Mechanistically-driven investigation of pegcrisantaspase combination therapy against acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 884.

Pathophysiology of drug-induce peripheral neuropathy in patients with multiple myeloma.

Multiple myeloma (MM) is a disease of unknown, complex etiology that affects primarily older adults. The course of the disease and the patients' survival time are very heterogeneous, but over the last decade, clear progress in the treatment of this incurable disease has been observed. Therapeutics that have proven to be highly effective include the immunomodulatory drug thalidomide and its newer analogs, lenalidomide and pomalidomide, as well as the proteasome inhibitors bortezomib and carfilzomib. However, the administration of some of the treatments, e.g., thalidomide or bortezomib, has also been associated with the occurrence of a serious and common adverse effect, drug-induced peripheral neuropathy. The mechanism of the development of the peripheral neuropathy is poorly understood. Nevertheless, one of its potential causes could be inadequate concentrations of crucial trophic factors, including neurotrophic and/or angiogenic factors, which are responsible for the proliferation, differentiation, survival and death of neuronal and nonneuronal cells.

Resveratrol Sensitizes Carfilzomib-Induced Apoptosis via Promoting Oxidative Stress in Multiple Myeloma Cells.

The proteasome inhibitor is a target therapy for multiple myeloma (MM) patients, which has increased the overall survival rate of multiple myeloma in clinic. However, relapse and toxicity are major challenges for almost all MM patients. Thus, there is an urgent need for an effective and less toxic combination therapy. Here, we demonstrated that a natural compound, resveratrol (RSV) displayed anti-proliferative activity in a dose- and time-dependent manner in a panel of MM cell lines. More importantly, a low concentration of RSV was synergistic with a low dose of the proteasome inhibitor carfilzomib (CFZ) to induce apoptosis in myeloma cells. Further studies showed that mitochondria was a key regulatory site after RSV/CFZ combination treatment. RSV induced the release of second mitochondria-derived activator of caspase (Smac) in a dose-dependent manner and kept the Smac in a high level after combination with CFZ. Also, RSV was additive with CFZ to increase reactive oxygen species (ROS) production. Moreover, a stress sensor SIRT1, with deacetylase enzyme activity, was remarkably downregulated after RSV/CFZ combination, thereby significantly decreasing its target protein, survivin in MM cells. Simultaneously, autophagy was invoked after RSV/CFZ combination treatment in myeloma cells. Further inhibition of autophagy could increase more ROS production and apoptosis, indicating a close linkage between autophagy and proteasome to modulate the oxidative stress. Together, these findings suggest that induction of multiple stress responses after RSV/CFZ combination is a major mechanism to synergistically inhibit MM cell growth and reduce the toxicity of CFZ in MM cells. This study also provides an important rationale for the clinic to consider an autophagy inhibitor for the combination therapy in MM patients.

Enhanced Glioblastoma Targeting Ability of Carfilzomib Enabled by a DA7R-Modified Lipid Nanodisk.

The robust proliferation of tumors relies on a rich neovasculature for nutrient supplies. Therefore, a basic strategy of tumor targeting therapy should include not only killing regular cancer cells but also blocking tumor neovasculature. D-peptide DA7R, which was previously reported to specifically bind vascular endothelial growth factor receptor 2 (VEGFR2) and neuropilin-1 (NRP-1), could achieve the goal of multitarget recognition. Accordingly, the main purposes of this work were to establish a carfilzomib-loaded lipid nanodisk modified with multifunctional peptide DA7R (DA7R-ND/CFZ) and to evaluate its anti-glioblastoma efficacy in vitro and in vivo. It is testified that the DA7R peptide-conjugated lipid nanodisk can be specifically taken up by U87MG cells and HUVECs. Furthermore, DA7R-ND demonstrated a more enhanced penetration than that of the nonmodified formulation on the tumor spheroid model in vitro and more tumor region accumulation in vivo on the subcutaneous and intracranial tumor-bearing nude mice model. DA7R-ND was shown to co-localize with tumor neovasculature in vivo. When loaded with proteasome inhibitor carfilzomib, the DA7R-decorated nanodisk could remarkably suppress tumor proliferation, extend survival time of nude mice bearing an intracranial tumor, and inhibit neovasculature formation with an efficacy higher than that of the nonmodified nanodisk in vitro and in vivo. The present study verified that the heptapeptide DA7R-conjugated nanodisk is a promising nanocarrier for glioblastoma targeting therapy.

Preclinical comparison of proteasome and ubiquitin E1 enzyme inhibitors in cutaneous squamous cell carcinoma: the identification of mechanisms of differential sensitivity.

Proteasome inhibitors have distinct properties and the biochemical consequences of suppressing ubiquitin E1 enzymes and the proteasome differ. We compared the effects of the proteasome inhibitors bortezomib, ixazomib and carfilzomib and the ubiquitin E1 enzyme inhibitor MLN7243/TAK-243 on cell viability and cell death in normal keratinocytes and cutaneous squamous cell carcinoma (cSCC) cell lines. The effects of both a pulse of treatment and more extended incubation were investigated. This is relevant to directly-delivered therapy (topical treatment/intratumoral injection) where the time of exposure can be controlled and a short exposure may better reflect systemically-delivered inhibitor pharmacokinetics. These agents can selectively kill cSCC cells but there are variations in the pattern of cSCC cell line sensitivity/resistance. Variations in the responses to proteasome inhibitors are associated with differences in the specificity of the inhibitors for the three proteolytic activities of the proteasome. There is greater selectivity for killing cSCC cells compared to normal keratinocytes with a pulse of proteasome inhibitor treatment than with a more extended exposure. We provide evidence that c-MYC-dependent NOXA upregulation confers susceptibility to a short incubation with proteasome inhibitors by priming cSCC cells for rapid BAK-dependent death. We observed that bortezomib-resistant cSCC cells can be sensitive to MLN7243-induced death. Low expression of the ubiquitin E1 UBA1/UBE1 participates in conferring susceptibility to MLN7243 by increasing sensitivity to MLN7243-mediated attenuation of ubiquitination. This study supports further investigation of the potential of proteasome and ubiquitin E1 inhibition for cSCC therapy. Direct delivery of inhibitors could facilitate adequate exposure of skin cancers.

Cardiovascular Complications of Multiple Myeloma Treatment: Evaluation, Management, and Prevention

Multiple myeloma treatment regimens consist of proteasome inhibitors (bortezomib, carfilzomib, and ixazomib), immunomodulatory drugs (thalidomide, lenalidomide, and pomalidomide), and steroids. In this paper, we will review the pathophysiology and associated cardiotoxicities of the different multiple myeloma therapeutic modalities and present methods to mitigate the development of cardiovascular complications. Although proteasome inhibitors and immunomodulatory drugs have led to significant improvements in oncologic outcomes, there is increasing evidence of serious cardiovascular side effects which may be exacerbated in the setting of underlying cardiovascular risk factors or disease. Cardiotoxicities include cardiomyopathy and heart failure, accelerated hypertension, arrhythmias, and both arterial and venous thromboembolism. Given the frequency of cardiovascular risk factors in multiple myeloma patients as well as the cardiotoxicities associated with the different treatment regimens, it is essential to closely monitor these patients. Collaboration between cardiologists and oncologists is necessary to ensure patients receive optimal cancer treatment while minimizing cardiovascular risk.

Proteasome inhibition blocks necroptosis by attenuating death complex aggregation

Proteasome inhibitors have achieved clinical success because they trigger intrinsic and extrinsic cell death to eliminate susceptible human cancers. The ubiquitin-proteasome protein degradation system regulates signaling pathways by controlling levels of components such as cellular inhibitor of apoptosis (cIAP)1 and cIAP2 in TNF-mediated cell death. Here, we sought to evaluate the contribution of necroptosis to the cell death pattern induced by the specific proteasome inhibitor Carfilzomib (Cf). Proteasome inhibitor-sensitive multiple myeloma cell lines die in response to Cf by apoptosis in combination with serine protease-dependent death, without any contribution of RIPK3-dependent necroptosis. Proteasome inhibition leads to the induction of apoptotic markers such as activated caspase-3 rather than necroptotic markers such as phosphorylated-MLKL in all cell lines tested. In HT-29 cells, Cf attenuates the late RIPK1 interaction with TNFR1 during TNF-induced necroptosis without altering the sensitivity of cIAP antagonists. Cf treatment results in decreased translocation of death signaling components RIPK1, FADD, caspase-8, cFLIP, and RIPK3 to detergent insoluble fractions. Our results show that proteasome inhibition with Cf impairs necroptosis and favors apoptosis even in cells with intact necroptotic machinery. Following the induction of TNFR1-mediated necroptosis, proteasome activity stabilizes effective aggregation and activation of ripoptosome/necrosome complexes.