Second-generation Proteasome Inhibitor Research Articles

Effect and mechanism of protease inhibitor oprozomib on doxorubicin sensitivity of hepatocellular carcinoma cells

This study was to examine the impact of Oprozomib (OPZ), an oral second-generation proteasome inhibitor, on the sensitivity of hepatocellular carcinoma (HCC) cells to doxorubicin (DOX), a commonly used chemotherapy drug for the treatment of HCC. HCC cells were incubated with OPZ or DOX. Cell proliferation was assessed using MTT and colony formation assay, while cell migration and invasion were evaluated using scratch assay and Transwell assay. Cell apoptosis was measured using flow cytometry, and apoptosis-related molecules were determined through Western blot analysis. The proliferation, migration, and invasion of HCC cells were effectively suppressed by OPZ in a dose-dependent manner. This inhibition was achieved through the upregulation of pro-apoptotic genes, resulting in the promotion of apoptosis. Furthermore, OPZ significantly augmented the cytotoxicity and apoptosis induced by DOX. OPZ alone can effectively inhibit cell proliferation and induce apoptosis. OPZ can enhance DOX sensitivity and cellular apoptosis.

Functional Investigation of IGF1R Mutations in Multiple Myeloma.

High expression of the receptor tyrosine kinase (RTK) insulin-like growth factor-1 receptor (IGF1R) and RTK mutations are associated with high-risk/worse prognosis in multiple myeloma (MM). Combining the pIGF1R/pINSR inhibitor linsitinib with the proteasome inhibitor (PI) bortezomib seemed promising in a clinical trial, but IGF1R expression was not associated with therapy response. Because the oncogenic impact of IGF1R mutations is so far unknown, we investigated the functional impact of IGF1R mutations on survival signaling, viability/proliferation and survival response to therapy. We transfected four human myeloma cell lines (HMCLs) with IGF1RWT, IGF1RD1146N and IGF1RN1129S (Sleeping Beauty), generated CRISPR-Cas9 IGF1R knockouts in the HMCLs U-266 (IGF1RWT) and L-363 (IGF1RD1146N) and tested the anti-MM activity of linsitinib alone and in combination with the second-generation PI carfilzomib in seven HMCLs. IGF1R knockout entailed reduced proliferation. Upon IGF1R overexpression, survival signaling was moderately increased in all HCMLs and slightly affected by IGF1RN1129S in one HMCL, whereby the viability remained unaffected. Expression of IGF1RD1146N reduced pIGF1R-Y1135, especially under serum reduction, but did not impact downstream signaling. Linsitinib and carfilzomib showed enhanced anti-myeloma activity in six out of seven HMCL irrespective of the IGF1R mutation status. In conclusion, IGF1R mutations can impact IGF1R activation and/or downstream signaling, and a combination of linsitinib with carfilzomib might be a suitable therapeutic approach for MM patients potentially responsive to IGF1R blockade.

Using protein turnover assay to explore the drug mechanism of Carfilzomib.

Carfilzomib (CFZ) is the second-generation proteasome inhibitor that is approved by Food and Drug Administration (FDA) of USA for the treatment of relapsed and refractory multiple myeloma. Although the preclinical and clinical efficacy of CFZ is obvious, the mechanism by which CFZ leads to cell death has not been fully elucidated. Since CFZ primarily functions as a proteasome inhibitor, profiling CFZ-induced changes in protein turnover at the systematic level is sufficient and necessary. In this study, we characterize the effects of CFZ on the stability of 15,000 human proteins using Protein Turnover Assay (ProTA). CFZ affects fundamental cellular glycolysis, nitric oxide production and proteasome subunit homeostasis in multiple myeloma cells. In addition, LY294002 or KU-0063794 has synergistic effects with CFZ in multiple myeloma treatment. A profound understanding of how cells respond to chemotherapeutic agents provides insights into the basic mechanism of drug function and the rationale for CFZ combination therapy.

The proteasome inhibitor carfilzomib exerts anti-inflammatory and antithrombotic effects on the endothelium

BackgroundCarfilzomib (CFZ) is a second-generation proteasome inhibitor used to treat multiple myeloma. Potent inhibition of the proteasome results in chronic proteotoxic endoplasmic reticulum (ER) stress, leading to apoptosis. While CFZ has improved survival rates in multiple myeloma, it is associated with an increased risk of cardiovascular adverse effects. While this has been putatively linked to cardiotoxicity, CFZ could potentially also exhibit adverse effects on the endothelium. ObjectivesTo investigate the effects of CFZ on the endothelium. MethodsHuman umbilical vein endothelial cells (HUVECs) were treated with CFZ, and expression of relevant markers of ER stress, inflammation, and thrombosis was measured and functionally assessed. ResultsCFZ failed to induce ER stress in HUVECs but induced the expression of Kruppel-like factor 4, endothelial nitric oxide synthase, tissue plasminogen activator, and thrombomodulin and reduced tumor necrosis factor alpha (TNFα)-mediated intercellular adhesion molecule 1 and tissue factor expression, suggesting a potential protective effect on the endothelium. Consistent with these observations, CFZ reduced leukocyte adhesion under shear stress and reduced factor Xa generation and fibrin clot formation on the endothelium following TNFα treatment and inhibited von Willebrand factor (VWF) and angiopoietin-2 exocytosis from Weibel–Palade bodies. Subsequently, CFZ inhibited the formation of VWF-platelet strings, and moreover, media derived from myeloma cell lines induced VWF release, a process also inhibited by CFZ. ConclusionThese data demonstrate that CFZ is unable to induce ER stress in confluent resting endothelial cells and can conversely attenuate the prothrombotic effects of TNFα on the endothelium. This study suggests that CFZ does not negatively alter HUVECs, and proteasome inhibition of the endothelium may offer a potential way to prevent thrombosis.

The Efficacy of Carfilzomib Treatment in Bortezomib-Refractory Patients-Real Life Experience in a Tertiary Romanian Hospital.

Background: Proteasome inhibitors (PIs) represent one of the most effective classes of therapy for patients with multiple myeloma (MM) and are incorporated in many of the current treatment regimens. The first-generation PI, bortezomib, has shown impressive results in patients with either newly diagnosed or relapsed/refractory MM, but once patients become resistant, treatment is increasingly challenging. Although the existing data show that the second-generation PI, carfilzomib, is highly efficient, there is still limited knowledge regarding the response to carfilzomib-based therapy in bortezomib-resistant patients. The aim of this study was to evaluate carfilzomib treatment performance in bortezomib-sensitive versus -refractory patients, in a real-life eastern European country setting. Methods: We retrospectively evaluated 127 adult patients exposed to bortezomib with relapsed or refractory MM, that subsequently received a carfilzomib-based therapy. We investigated the differences in the overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) after carfilzomib-based therapy between the two patient groups. Results: The ORR in the bortezomib-sensitive group was significantly higher than that in the refractory group, leading to a superior PFS in this category of patients. For patients presenting with a high cytogenetic risk, we observed a significant difference in PFS between the bortezomib-sensitive and -refractory group, while standard cytogenetic risk patients presented a similar PFS regardless of the bortezomib sensitivity status. In addition, in patients with ISS (International Staging System) stage I or II, the previous sensitivity to bortezomib correlated with an improved PFS, while for patients with ISS stage III, both groups had a comparable PFS. No significant differences in OS were observed between the two groups. Conclusions: In countries where novel or experimental therapies are not readily available, carfilzomib-based therapy can still be a viable therapy option for patients presenting with bortezomib-refractory status, an ISS stage III, and standard cytogenetic risk.

Carfilzomib activates ER stress and JNK/p38 MAPK signaling to promote apoptosis in hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is one of the most prevalent and deadly cancers in the world, which is frequently diagnosed at a late stage. HCC patients have a poor prognosis due to the lack of an efficacious therapeutic strategy. Approved drug repurposing is a way for accelerating drug discovery and can significantly reduce the cost of drug development. Carfilzomib (CFZ) is a second-generation proteasome inhibitor, which is highly efficacious against multiple myeloma and has been reported to possess potential antitumor activities against multiple cancers. However, the underlying mechanism of CFZ on HCC is still unclear. Here, we show that CFZ inhibits the proliferation of HCC cells through cell cycle arrest at the G2/M phase and suppresses the migration and invasion of HCC cells by inhibiting epithelial-mesenchymal transition. We also find that CFZ promotes reactive oxygen species production to induce endoplasmic reticulum (ER) stress and activate JNK/p38 MAPK signaling in HCC cells, thus inducing cell death in HCC cells. Moreover, CFZ significantly inhibits HCC cell growth in a xenograft mouse model. Collectively, our study elucidates that CFZ impairs mitochondrial function and activates ER stress and JNK/p38 MAPK signaling, thus inhibiting HCC cell and tumor growth. This indicates that CFZ has the potential as a therapeutic drug for HCC.

In vivo activity of the second-generation proteasome inhibitor ixazomib against pediatric T-cell acute lymphoblastic leukemia xenografts

The overall survival rate of patients with T-cell acute lymphoblastic leukemia (T-ALL) is now 90%, although patients with relapsed T-ALL face poor prognosis. The ubiquitin-proteasome system maintains normal protein homeostasis, and aberrations in this pathway are associated with T-ALL. Here we demonstrate the in vitro and in vivo activity of ixazomib, a second-generation orally available, reversible, and selective proteasome inhibitor against pediatric T-ALL cell lines and patient-derived xenografts (PDXs) grown orthotopically in immunodeficient NOD.Cg-PrkdcscidIL2rgtm1Wjl/SzJAusb (NSG) mice. Ixazomib was highly potent in vitro, with half-maximal inhibitory concentration (IC50) values in the low nanomolar range. As a monotherapy, ixazomib significantly extended mouse event-free survival of five out of eight T-ALL PDXs in vivo.

The Relative Efficacy of Available Proteasome Inhibitors in Preventing Muscle Contractures Following Neonatal Brachial Plexus Injury.

Contractures following neonatal brachial plexus injury (NBPI) are associated with growth deficits in denervated muscles. This impairment is mediated by an increase in muscle protein degradation, as contractures can be prevented in an NBPI mouse model with bortezomib (BTZ), a proteasome inhibitor (PI). However, BTZ treatment causes substantial toxicity (0% to 80% mortality). The current study tested the hypothesis that newer-generation PIs can prevent contractures with less severe toxicity than BTZ. Unilateral brachial plexus injuries were surgically created in postnatal (5-day-old) mice. Following NBPI, mice were treated with either saline solution or various doses of 1 of 3 different PIs: ixazomib (IXZ), carfilzomib (CFZ), or marizomib (MRZ). Four weeks post-NBPI, mice were assessed for bilateral passive range of motion at the shoulder and elbow joints, with blinding to the treatment group, through an established digital photography technique to determine contracture severity. Drug toxicity was assessed with survival curves. All PIs prevented contractures at both the elbow and shoulder (p < 0.05 versus saline solution controls), with the exception of IXZ, which did not prevent shoulder contractures. However, their efficacies and toxicity profiles differed. At lower doses, CFZ was limited by toxicity (30% to 40% mortality), whereas MRZ was limited by efficacy. At higher doses, CFZ was limited by loss of efficacy, MRZ was limited by toxicity (50% to 60% mortality), and IXZ was limited by toxicity (80% to 100% mortality) and loss of efficacy. Comparisons of the data on these drugs as well as data on BTZ generated in prior studies revealed BTZ to be optimal for preventing contractures, although it, too, was limited by toxicity. All of the tested second-generation PIs were able to reduce NBPI-induced contractures, offering further proof of concept for a regulatory role of the proteasome in contracture formation. However, the narrow dose ranges of efficacy for all PIs highlight the necessity of precise proteasome regulation for preventing contractures. Finally, the substantial toxicity stemming from proteasome inhibition underscores the importance of identifying muscle-targeted strategies to suppress protein degradation and prevent contractures safely. Although PIs offer unique opportunities to establish critical mechanistic insights into contracture pathophysiology, their clinical use is contraindicated in patients with NPBI at this time.

Single-Center Experience of Carfilzomib-Based Combinations for Patients with Lymphoplasmacytic Lymphoma

Single-Center Experience of Carfilzomib-based Combinations for patients with Lymphoplasmacytic Lymphomas Background Use of bortezomib in Waldenstrom macroglobulinemia (WM) produces a response rate of 60-70% in treatment naïve or relapsed WM(Dimopoulos et al., 2005)(Chen et al., 2006). However, it is associated with an increased risk of peripheral neuropathy (PN). This is important considering that WM can be associated frequently with PN. Carfilzomib(K) is a second-generation proteasome inhibitor that is associated with a lower PN risk and offers a PN-sparing approach for treatment for patients(pts) with WM. In the CARD trial, K-based combinations produced a high ORR with a tolerable safety profile(Treon et al., 2014). We report our single-center experience with the use of K-based combinations in pts with treatment naïve or relapsed lymphoplasmacytic lymphoma (LPL). Patients and Methods We conducted a single-center retrospective study on an IRB-approved protocol for all pts who were treated with K-based combinations 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. Efficacy outcomes included overall response rates (ORR), progression free survival (PFS), overall survival (OS). Survival analysis was performed using the Kaplan-Meier method including PFS and Overall survival (OS). PFS was defined as time from initiation of treatment to progression of disease or death whichever occurred first. OS was defined as time from initiation of treatment to death. The consensus criteria from the 6 th International Workshop on WM were utilized for response assessment. Results We identified 36 patients with a diagnosis of WM and 1 patient with IgA-kappa LPL who were treated with K-based combinations between June 2015 and July 2022. 4 patients (10.8%) had a concomitant diagnosis of systemic light chain amyloidosis (AL). 67.6% pts were male, the median age at treatment initiation was 67.5 yrs. Majority of the pts were treatment naïve (86.4%, N=32). Data for MYD88 mutation was available in 30 pts, 93.3% (n=28) were found to have MYD88 mutation on next generation sequencing (NGS) performed on bone marrow aspirate samples. As per the RPISSWM risk stratification, 30% (9) pts were found to have poor risk, 33.3% (10) had intermediate risk and 36.7% (11) had good risk. Median bone marrow involvement by WM was 30%. The majority of the pts (91.9%, n=34) received KCD-R (Carfilzomib, cyclophosphamide, dexamethasone and rituximab) as their treatment regimen, while the remaining patients received KD-R(carfilzomib, dexamethasone and rituximab). Pts received a median of 6 cycles of treatment. ORR was found to be 97.3% (n=36) with 48.6%(n=18) pts achieving a very good partial response or better (&amp;gt;=VGPR). Median PFS was found to be 51.08 months and median OS was not reached (NR). Two patients needed treatment discontinuation following 1 cycle or less, due to toxicity (dyspnea, one of which was non-cardiogenic) associated with carfilzomib and were changed to an alternative regimen (Bortezomib, cyclophosphamide, dexamethasone and rituximab). Further data for toxicities are being gathered and will be presented at the meeting. Baseline characteristics and outcomes data are summarized in Table 1. Conclusions K-based combinations produce a high ORR with durable responses in patients with symptomatic LPL. Treatment discontinuation rate due to toxicity was low with only two patients needing change of therapy in our cohort. Our data supports the use of K-based combinations in pts with treatment naïve or relapsed LPL.

A Single Center Real-World Data Comparing Salvage Autologous Hematopoietic Stem-Cell Transplantation, Selinexor Combo and Elranatamab Alone Among Triple Class Refractory Myeloma Patients: Better Efficacy with Elranatamab

Introduction: A vast majority of multiple myeloma (MM) patients may experience relapse and require multiple lines of therapy. The choice of the next treatment depends on multiple factors including the response, tolerance to prior therapies, as well as access to novel treatments. Among triple-class refractory patients, in real-world settings where CAR-T therapies are not available, options are limited. Here we report a single-center experience comparing salvage autologous hematopoietic stem-cell transplantation (sAHCT), selinexor combinations, and elranatamab in this highly unmet needed group. Patients &amp; Methods: Between January 2015 and June 2023, 50 patients at our center underwent sAHCT for treatment of refractoriness to all available drugs. Salvage AHCT is defined as being transplanted for treatment of MM after evidence of disease progression not responding to second-generation proteasome inhibitors (PI), immunomodulating agents (IMID), or antiCD38 monoclonal antibody. We compared the outcomes of these patients with RRMM patients who had exhausted their treatment options and were progressing on their last line of therapy to receive single agent Elranatamab at a step-up dosing starting with escalating to 72 mg once a week for six months and on alternate weeks thereafter. Selinexor was administered with either Bortezomib(n:8) or Pomalidomide(n:9) at a dose of 60-100 mg/week every 5-6 weeks. Response and disease progression were assessed according to the IMWG criteria. Results: Patients' characteristics and the outcomes are shown in Table. The median age of patients was similar in both groups. Patients were heavily treated with a median of 4 prior lines of therapy (1-17) and 7 out of 13 carried high-risk cytogenetics in elranatamab group. All patients were triple-class refractory. Five patients responded to DCEP bridging therapy prior to sAHCT. Selinexor (n: 11, 64.7%) and elranatamab (n:5 patients,38.5%) were administered after sAHCT. One patient underwent sAHCT due to progression under Selinexor treatment. In the sAHCT group, 68% of patients relapsed within a median of 7.4 months. Median DFS was significantly prolonged with single agent elranatamab (NR) compared to sAHCT (7.3 mos) and Selinexor-combos (7.3 mos) (p=0.4) (Figure). Adverse events on selinexor regimens included fatigue, nausea, and thrombocytopenia which were managed with Selinexor dose adjustment and supportive care. All patients received the recommended step-up priming dose elranatamab regimen, 69.2% of our patients experienced a Grade 1 cytokine release syndrome (CRS) during the first cycle. None of these patients had to stop treatment due to toxicity. Early sAHSCT mortality was not observed either. At the time of the analysis, all patients on Selinexor have progressed after a median follow-up of 14.7 months. Elranatamab patients are currently at 5 months follow-up and 7/ 13 are still on treatment. Conclusion: Upfront AHCT is a cost-effective treatment option with a decreasing efficacy in late relapses. In this RWE study, we have been able to confirm the inferiority of AHCT at late stages. As seen in our series cytogenetic profile worsens with an increase in the prior number of lines of treatment which are both highest among patients who have received elranatamab. Despite these unfavorable features, single-agent elranatamab has been able to attain the highest overall response rates, unfortunately not reflecting on PFS yet, due to short follow-up. Furthermore, two of these had progressed while on a BCMA immunotoxin Rx and have responded to elranatamab. In conclusion, even with short follow-up single-agent elranatamab is a tolerable and highly effective regimen

Carfilzomib suppressed LDHA-mediated metabolic reprogramming by targeting ATF3 in esophageal squamous cell carcinoma

Carfilzomib, a second-generation proteasome inhibitor, has been approved as a treatment for relapsed and/or refractory multiple myeloma. Nevertheless, the molecular mechanism by which Carfilzomib inhibits esophageal squamous cell carcinoma (ESCC) progression largely remains to be determined. In the present study, we found that Carfilzomib demonstrated potent anti-tumor activity against esophageal squamous cell carcinoma both in vitro and in vivo. Mechanistically, carfilzomib triggers mitochondrial apoptosis and reprograms cellular metabolism in ESCC cells. Moreover, it has been identified that activating transcription factor 3 (ATF3) plays a crucial cellular target role in ESCC cells treated with Carfilzomib. Overexpression of ATF3 effectively antagonized the effects of carfilzomib on ESCC cell proliferation, apoptosis, and metabolic reprogramming. Furthermore, the ATF3 protein is specifically bound to lactate dehydrogenase A (LDHA) to effectively suppress LDHA-mediated metabolic reprogramming in response to carfilzomib treatment. Research conducted in xenograft models demonstrates that ATF3 mediates the anti-tumor activity of Carfilzomib. The examination of human esophageal squamous cell carcinoma indicated that ATF3 and LDHA have the potential to function as innovative targets for therapeutic intervention in the treatment of ESCC. Our findings demonstrate the novel function of Carfilzomib in modulating ESCC metabolism and progression, highlighting the potential of Carfilzomib as a promising therapeutic agent for the treatment of ESCC.

Carfilzomib-Loaded Ternary Polypeptide Nanoparticles Stabilized by Polycationic Complexation

Carfilzomib (CFZ) is a second-generation proteasome inhibitor showing great efficacy in multiple myeloma treatment, yet its clinical applications for other diseases such as solid cancers are limited due to low aqueous solubility and poor biostability. Ternary polypeptide nanoparticles (tPNPs) are drug carriers that we previously reported to overcome these pharmaceutical limitations by entrapping CFZ in the core of the nanoparticles and protecting the drugs from degradation in biological media. However, preclinical studies revealed that tPNPs would require further improvement in particle stability to suppress initial burst drug release and thus achieve prolonged inhibition of proteasome activity with CFZ against tumor cells in vivo. In this study, CFZ-loaded tPNPs are stabilized by polycations which have varying pKa values and thus differently modulate nanoparticle stability in response to solution pH. Through polyion complexation, the polycations appeared to stabilize the core of tPNPs entrapping CFZ-cyclodextrin inclusion complexes while allowing for uniform particle size before and after freeze drying. Interestingly, CFZ-loaded tPNPs (CFZ/tPNPs) showed pH-dependent drug release kinetics, which accelerated CFZ release as solution acidity increased (pH < 6) without compromising particle stability at the physiological condition (pH 7.4). In vitro cytotoxicity and proteasome activity assays confirmed that tPNPs stabilized with cationic polymers improved bioactivity of CFZ against CFZ-resistant cancer cells, which would be greatly beneficial in combination with pH-dependent drug release for treatment of solid cancers with drug resistance and tumor microenvironment acidosis by using CFZ and other proteasome inhibitors.

Longitudinal changes in echocardiographic variables and endothelial function to predict cardiovascular toxicities in patients with multiple myeloma receiving carfilzomib.

e20012 Background: Carfilzomib (CFZ) is a second-generation proteasome inhibitor with activity in multiple myeloma (MM) that is associated with cardiotoxicity and dyspnea. The pathophysiology and risk factors for developing these toxicities are not well described. We are conducting a prospective observational study (NCT04827563) of longitudinal changes in cardiovascular and endothelial function among MM patients receiving CFZ. We hypothesize that baseline and longitudinal variations in cardiovascular and endothelial function correlate with development of cardiotoxicity and dyspnea in MM patients receiving CFZ. Methods: Patients with MM receiving first-time CFZ therapy are prospectively enrolled and undergo the following study procedures prior to CFZ initiation and then every 2 weeks for the first 6 weeks of CFZ therapy (C1D1, C1D15, C2D1, C2D15): 24-hour ambulatory blood pressure monitoring, echocardiography, pulse wave velocity, and EndoPAT endothelial function assessment. Patient-reported outcomes are also collected. Cardiovascular adverse events (CVAEs) and dyspnea are assessed at all timepoints, as well as at 3 and 6 months after enrollment, by CTCAE v5.0 and are adjudicated by a cardio-oncologist. Patients with endothelial dysfunction will be defined as reactive hyperemia index (RHI) &lt;1.67 via EndoPAT. Baseline variables were analyzed with unpaired t-tests and longitudinal variables were analyzed by one-way repeated measures ANOVA. Results: Ten patients have completed 6 months of follow-up. Demographic data is summarized in the table. Four patients (40%) developed dyspnea, 2 with grade 1 and 2 with grade 3 at maximum, with most patients developing dyspnea by C1D15. Two patients had ongoing grade 1 dyspnea at follow-up. Four patients (40%) developed grade 3 or higher CVAEs, most of which were grade 3 hypertension and/or grade 3 HFpEF. Baseline left ventricular mass was significantly higher in patients who developed dyspnea compared to those who did not (p=0.040). EndoPAT values were significantly different between C1D1 and C1D15 in those with CVAEs (2.28 vs 1.74, p=0.0223). NTproBNP values were also significantly different between C1D1 and C1D15 in those with dyspnea (74.5 vs 129.3, p=0.006). Conclusions: MM patients that developed dyspnea during treatment with CFZ had a higher baseline LV mass and were more likely to develop increases in NTproBNP despite preserved ejection fraction, consistent with HFpEF. This group also had a greater change in EndoPAT values suggesting that short-term alterations in endothelial function may have a role in the development of dyspnea in those who may have the anatomic substrate for HFpEF. Clinical trial information: NCT04827563 . [Table: see text]

Synergistic Anti-Cancer Effects of Second-Generation Proteasome Inhibitor Carfilzomib with Doxorubicin and Dexamethasone Via p53-Mediated Apoptosis in Pre-B Acute Lymphoblastic Leukemia Cells

Background: The ubiquitin-proteasome system (UPS) plays a crucial role in regulating the levels and functions of a large number of proteins in the cell, which are important for cancer cell growth and survival. The proteasome is highly activated in B-cell precursor acute lymphoblastic leukemia (BCP-ALL), which is the most common malignancy in children. The attempt to inhibit proteasome as a therapeutic strategy has been successful for some malignancies.&#x0D; Materials and Methods: In this experimental study, human BCP-ALL cell lines NALM-6 and SUP-B15 were treated with carfilzomib with and without the chemotherapeutic agents. The XTT assay evaluated the viability of the cells. Cell cycle analysis and apoptosis assay were assessed by flow cytometry. RQ-PCR and western blotting evaluated the expression of pro-/anti-apoptotic signals. A drug combination study for synergistic or additive effects of carfilzomib with doxorubicin or dexamethasone was performed.&#x0D; Results: We observed that carfilzomib alone induced G2/M cell cycle arrest and caspase-dependent apoptosis in the human BCP-ALL cells (NALM-6 and SUP-B15). Gene and protein expression analysis indicated the upregulation of pro-apoptotic as well as downregulation of the cell survival and proliferative signals (P-value&lt;0.05). The synergy of carfilzomib with doxorubicin or dexamethasone was revealed in BCP-ALL cells.&#x0D; Conclusion: Our results indicated that proteasome inhibition induces p53-mediated apoptosis in BCP-ALL cells. Since carfilzomib has a synergistic effect with anti-leukemic agents doxorubicin and dexamethasone in BCP-ALL cells, this combined-modality approach might be befitting for patients who do not respond well to conventional chemotherapy.

The cytotoxic activity of carfilzomib together with nelfinavir is superior to the bortezomib/nelfinavir combination in non-small cell lung carcinoma

Chemotherapy resistance is still a major problem in the treatment of patients with non-small-cell-lung carcinoma (NSCLC), and novel concepts for the induction of cytotoxicity in NSCLC are highly warranted. Proteotoxicity, the induction of cytotoxicity by targeting the ubiquitin proteasome system, represents an appealing innovative strategy. The combination of the proteasome inhibitor bortezomib (BTZ) and the proteotoxic stress-inducing HIV drug nelfinavir (NFV) synergistically induces proteotoxicity and shows encouraging preclinical efficacy in NSCLC. The second-generation proteasome inhibitor carfilzomib (CFZ) is superior to BTZ and overcomes BTZ resistance in multiple myeloma patients. Here, we show that CFZ together with NFV is superior to the BTZ + NFV combination in inducing endoplasmic reticulum stress and proteotoxicity through the accumulation of excess proteasomal substrate protein in NSCLC in vitro and ex vivo. Interestingly, NFV increases the intracellular availability of CFZ through inhibition of CFZ export from NSCLC cells that express multidrug resistance (MDR) protein. Combining CFZ with NFV may therefore represent a future treatment option for NSCLC, which warrants further investigation.

Preparation, characterization, and toxicity assessment of carfilzomib-loaded nickel-based metal-organic framework: Evidence from in-vivo and in-vitro experiments

The introduction of innovative medications such as proteasome inhibitors (PIs) has significantly increased the response rate and overall survival of cancer patients. Carfilzomib (CFZ) is a second-generation PI that has shown favorable outcomes in treating relapsed/refractory and newly diagnosed multiple myeloma patients in clinical trials. In the present study, novel nickel-based metal-organic frameworks (Ni-MOFs) were designed, loaded with CFZ, and utilized for the first time as a drug delivery platform for targeted cancer therapy. Ni-MOFs were prepared via a simple bottom-up solvothermal method, and characterized in terms of morphology, size distribution, porosity, and release behavior. They have a mesoporous structure with a mean pore diameter of 16.2 nm. Both unloaded and CFZ-loaded Ni-MOFs exhibit nanocube and nanorod-like morphologies and a size range of 150–500 nm. The in-vitro and in-vivo effects of CFZ-loaded Ni-MOFs were compared with those of standard drugs. A high loading efficiency with a controlled release behavior was observed. MTT results demonstrated that CFZ-loaded Ni-MOFs exert higher cytotoxic effects than free CFZ against cancer cells, this effect being more pronounced in A549 lung cancer cells. Besides, they also lead to a stronger increase of the mRNA levels of TP53 in malignant cells. Rats treated with free and loaded CFZ significantly increased biochemical parameters, namely serum alanine aminotransferase (ALT), serum creatinine, blood urea nitrogen (BUN), aspartate aminotransferase (AST), and liver malondialdehyde (MDA). Moreover, a high dose of CFZ-loaded Ni-MOFs caused severe histopathological alterations. Altogether, our findings provide rational evidence for future studies using Ni-MOFs as promising carriers of PIs such as CFZ, for targeted drug delivery.

Size optimization of carfilzomib nanocrystals for systemic delivery to solid tumors.

Carfilzomib (CFZ) is a second-generation proteasome inhibitor effective in blood cancer therapy. However, CFZ has shown limited efficacy in solid tumor therapy due to the short half-life and poor tumor distribution. Albumin-coated nanocrystal (NC) formulation was shown to improve the circulation stability of CFZ, but its antitumor efficacy remained suboptimal. We hypothesize that NC size reduction is critical to the formulation safety and efficacy as the small size would decrease the distribution in the reticuloendothelial system (RES) and selectively increase the uptake by tumor cells. We controlled the size of CFZ-NCs by varying the production parameters in the crystallization-in-medium method and compared the size-reduced CFZ-NCs (z-average of 168nm, NC168) with a larger counterpart (z-average of 325nm, NC325) as well as the commercial CFZ formulation (CFZ-CD). Both CFZ-NCs showed similar or higher cytotoxicity than CFZ-CD against breast cancer cells. NC168 showed greater uptake by cancer cells, less uptake by macrophages and lower immune cell toxicity than NC325 or CFZ-CD. NC168, but not NC325, showed a similar safety profile to CFZ-CD in vivo. The biodistribution and antitumor efficacy of CFZ-NCs in mice were also size-dependent. NC168 showed greater antitumor efficacy and tumor accumulation but lower RES accumulation than NC325 in 4T1 breast cancer model. These results support that NC formulation with an optimal particle size can improve the therapeutic efficacy of CFZ in solid tumors.

Multicenter Open Label Phase 2 Study of Isatuximab Plus Pomalidomide and Dexamethasone with Carfilzomib in Relapsed or Refractory Multiple Myeloma. Iskpd - IFM2018-03

Background. RRMM (relapsed or refractory multiple myeloma) remains a major change in the Myeloma disease development as it implies a shortening in overall survival with subsequent relapses; and consequently, RRMM is in constant need of novel treatment options to prolong survival. The triplet-based association of antiCD38 immunotherapy (antiCD38 IT) with either second generation of Imids (Pomalidomide) and dexamethasone or second-generation proteasome inhibitors (PI) such as Carfilzomib and dexamethasone has become the new standard of care in early relapse MM. However, quadruplet-based regimens (antiCD38 immunotherapy +Imids +PI +dexamethasone) have transformed the treatment landscape in the upfront setting, improving MRD (minimal residual disease) and survivals. We hypothesized that a quadruplet-based regimens (antiCD38 immunotherapy +Imids +PI +dexamethasone) would further improved MRD and survival in early RRMM. Here, we describe a phase II multicentric, open-label study, of isatuximab (antiCD38 IT), pomalidomide and dexamethasone plus carfilzomib (IsKPd/ IFM2018-03, NCT04287855) for patients with early RRMM. Study design and Methods. Approximately 90 patients will receive the association isatuximab, pomalidomide and dexamethasone with carfilzomib (IsKPd). Eligible patients are adults aged ≥18 years old with RRMM previously treated with 1 or 2 lines of therapy, including lenalidomide, prior to the study entry. Patients were excluded if they were refractory to any anti-CD38 monoclonal antibody or to carfilzomib, or if they were previously exposed to pomalidomide. Isatuximab will be given by IV route at 10 mg/kg on days 1, 8, 15, and 22 of cycle 1, on days 1 and 15 from cycle 2 to 12 and on day 1 only from cycle 13, 28-day cycles. Carfilzomib will be given by IV route at 20/27 mg/m² on days 1-2, 8-9, 15-16 during cycle 1, at 56mg/m² on days 1, 8, 15 from cycle 2 to 13 and at 56mg/m² on days 1 and 15 after cycle 13. Pomalidomide will be administered by oral route at 3 mg daily on days 1 to 21 in cycle 1 and at 4 mg daily from cycle 12. Dexamethasone will be given by oral route at 40/20 mg daily on days 1, 8, 15 and 22. The primary objective is to evaluate the MRD rate at 10-5 in patients with RRMM treated with IsKPd. Patients will pursue Isa-KPd until progression or unacceptable toxicity. Key secondary objectives include the survival analysis (OS, PFS, EFS, TTNT), response rates and duration of response and evaluation of the safety profile. The IFM2018-03 study is currently enrolling patients in several centers in France. The study is expected to complete recruitment in 2022 and read primary end point in 2023. Clinical trial information: NCT04287855.

Combination of Second-Generation Proteasome Inhibitor Carfilzomib with Bortezomib in Four Different Breast Cancer Cell Lines.

Proteasome inhibitors target different pathways in cells and therefore are promising drugs in cancer therapy. The use of these inhibitors is approved mainly in hematological cancers, and recently many clinical trials and preclinical studies have been conducted on efficacy in solid tumors. Carfilzomib is a second-generation inhibitor and was developed to decrease the side effects of bortezomib. Although there are many valid therapies for breast cancer, resistance and recurrence are inevitable in many cases and the proteasomal system plays an important role in related pathways. This study is a preliminary work to evaluate the combined effects of bortezomib and carfilzomib in four different breast cancer cells. MDA-MB-231, MCF-7, UACC-2087, and SKBR-3 cell lines were used. Cell viability was determined using bortezomib and carfilzomib alone and in combination. Combination effect values were determined using the Chou- Talalay method. Apoptosis, proteasome activity, cleaved PARP, and HSP70 expressions were analyzed in the determined doses. The response to the combination of the two inhibitors was different in four cell lines. Apoptosis was significantly higher in combination groups compared to carfilzomib in three cell lines except for SKBR-3, and higher in the combination group compared to bortezomib only in UACC-2087. Combination decreased cleaved PARP levels in MDA-MB-231 and MCF-7 and increased SKBR-3 compared to bortezomib. HSP70 levels decreased in combination with UACC-2087 and SKBR-3 compared to carfilzomib. Taken together, the combination of the two inhibitors was more apoptotic compared to carfilzomib and apoptosis was higher only in UACC-2087 compared to bortezomib. This apoptosis data can not be directly correlated to the degree of proteasome inhibition, PARP cleavage, and HSP70 response.

Proteasome Inhibitors and Their Potential Applicability in Osteosarcoma Treatment.

Simple SummaryBone cancer has seen minimal benefits in therapeutic options in the past 30 years. Proteasome inhibitors present a new avenue of research for the treatment of bone cancer. Proteasome inhibitors impair the function of the proteasome, a structure within the cell that removes unwanted and misfolded proteins. Bone cancer cells heavily rely on the proteasome to properly function and survive. Impairing the proteasome function can have detrimental consequences and lead to cell death. This review provides a thorough summary of the in vitro, in vivo, and clinical research that has explored proteasome inhibitors for the treatment of bone cancer.Osteosarcoma (OS) is the most common type of bone cancer, with ~30% of patients developing secondary/metastatic tumors. The molecular complexity of tumor metastasis and the lack of effective therapies for OS has cultivated interest in exploiting the proteasome as a molecular target for anti-cancer therapy. As our understanding towards the behavior of malignant cells expands, it is evident that cancerous cells display a greater reliance on the proteasome to maintain homeostasis and sustain efficient biological activities. This led to the development and approval of first- and second-generation proteasome inhibitors (PIs), which have improved outcomes for patients with multiple myeloma and mantle cell lymphoma. Researchers have since postulated the therapeutic potential of PIs for the treatment of OS. As such, this review aims to summarize the biological effects and latest findings from clinical trials investigating PI-based treatments for OS. Integrating PIs into current treatment regimens may better outcomes for patients diagnosed with OS.