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The novel proteasome inhibitor NPI-0052 has been shown to sensitize tumor cells to apoptosis by various chemotherapeutic drugs and tumor necrosis factor–related apoptosis-inducing ligand (TRAIL), although the mechanisms involved are not clear. We hypothesized that NPI-0052–mediated sensitization may result from NF-κB inhibition and downstream modulation of the metastasis inducer Snail and the metastasis suppressor/immunosurveillance cancer gene product Raf-1 kinase inhibitory protein (RKIP). Human prostate cancer cell lines were used as models, as they express different levels of these proteins. We show that NPI-0052 inhibits both NF-κB and Snail and induces RKIP expression, thus resulting in cell sensitization to CDDP and TRAIL. The direct role of NF-κB inhibition in sensitization was corroborated with the NF-κB inhibitor DHMEQ, which mimicked NPI-0052 in sensitization and inhibition of Snail and induction of RKIP. The direct role of Snail inhibition by NPI-0052 in sensitization was shown with Snail small interfering RNA, which reversed resistance and induced RKIP. Likewise, the direct role of RKIP induction in sensitization was revealed by both overexpression of RKIP (mimicking NPI-0052) and RKIP small interfering RNA that inhibited NPI-0052–mediated sensitization. These findings show that NPI-0052 modifies the NF-κB-Snail-RKIP circuitry in tumor cells and results in downstream inhibition of antiapoptotic gene products and chemoimmunosensitization. The findings also identified Snail and RKIP as targets for reversal of resistance. [Cancer Res 2009;69(21):8376–85]

Supplementary Figure Legend from Pivotal Roles of Snail Inhibition and RKIP Induction by the Proteasome Inhibitor NPI-0052 in Tumor Cell Chemoimmunosensitization

Supplementary Figure 1 from Pivotal Roles of Snail Inhibition and RKIP Induction by the Proteasome Inhibitor NPI-0052 in Tumor Cell Chemoimmunosensitization

Background Multiple myeloma (MM) patients have variable responses to mRNA vaccination to COVID-19. Little is known regarding their vaccine-induced antibody levels over time. Methods We monitored spike IgG antibody levels over 24 weeks among a subset of 18 MM patients who showed a full response after two mRNA vaccinations. MM patients had a more rapid decline in antibody levels as compared to 8 healthy controls, with power law half-lives of 72 days (versus 107 days) and exponential half-lives of 37 days (versus 51 days). Results The patients with longer SARS-CoV-2 antibody half-lives were more likely to have undetectable monoclonal protein than those with shorter half-lives, suggesting better disease control may correlate with longer duration of vaccine-induced antibodies. Regardless, by 16 weeks post-second dose of mRNA vaccination, the majority of patients had antibody levels below 250 binding arbitrary units per milliliter, which would be unlikely to contribute significantly to preventing COVID-19. Conclusions Thus, even MM patients who respond adequately to vaccination are likely to require more frequent booster doses than the general population.

Introduction: Selinexor (Karyopharm Therapeutics) is an FDA-approved oral selective inhibitor of nuclear export (SINE) compound. It specifically blocks XPO1 enforcing the nuclear retention of tumor suppressor proteins restoring their anti-cancer functions. It also attenuates the phosphoinositide-3 kinase (PI3K)-AKT pathway by activating PTEN. Although activation of PI3K signaling is often detected in hematological malignancies, there are no data regarding the combination of selinexor with the PI3K inhibitor duvelisib for MM treatment. Thus, we evaluated the anti-myeloma effects of selinexor in combination with duvelisib in vitro and also studied alternative schedules of selinexor with dexamethasone in vivo using our MM xenograft models LAGκ-2. Methods: The human MM cell line U266 was obtained from ATCC. Primary MM tumor cells were isolated from MM patients’ bone marrow (BM) aspirates. Cell viability was quantified using the MTS cell proliferation assay. For the in vivo studies, the human myeloma xenograft LAGκ-2 was surgically implanted into SCID mice. Selinexor was administered via oral gavage at 2.5 mg/kg 5x per week, 5 mg/kg 4x per week on consecutive days, or 10 mg/kg 2x per week with one day between treatments. Dexamethasone was administered via intraperitoneal injection at 4 mg/kg 2x per week except the vehicle control. Results and Discussion: MTS assays showed selinexor induced concentration dependent inhibition of cell viability/proliferation in the MM cell line MM1s at 0.1, 0.4 and 1.6 μM. Selinexor alone at 0.2 μM reduced cell proliferation of primary MM tumor cells obtained from BM mononuclear cells (MCs) from a patient with progressive disease. We next examined cell viability in the presence of selinexor and duvelisib. MM1s or fresh BM mononuclear cells were incubated with a fixed concentration of selinexor (0.1μM) with increasing concentrations of duvelisib (1.5 μM -25 μM) for 48 h. The results showed that duvelisib enhanced the cytotoxic effects of selinexor in a concentration dependent manner. We also evaluated dosing and scheduling of selinexor and dexamethasone in vivo using SCID mice bearing LAGκ-2 MM xenografts. When selinexor was combined with dexamethasone, lower more frequent dosing showed greater inhibition of tumor growth than mid-range and higher less frequent dosing of this SINE. This study illustrates that the combination of selinexor and duvelisib showed enhanced cytotoxic effects in vitro compared with single agent treatment, and we will further evaluate the anti-MM effects of selinexor in combination with duvelisib in vivo using our human MM xenograft models. These studies suggest that the combination of a SINE and PI3K inhibitor may be effective for MM treatment. Citation Format: Haiming Chen, Stacy Behare, Mingjie Li, Marissa Goldwater, Ava Hekmati, Jasmin Cao, Rocky Levin, Ning Xu, James Berenson. Evaluation of the anti-myeloma effects of high and metronomic selinexor alone and in combination with duvelisib in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4195.

Blocking inhibitory immune receptors has shown limited clinical benefit in patients with multiple myeloma (MM), warranting the discovery of alternative immune inhibitory pathways. Blockade of the immune checkpoint TIGIT was shown to enhance anti-tumor immunity in MM pre-clinical models. In addition to TIGIT, the DNAM1 axis includes the novel inhibitory receptor PVRIG. Both TIGIT and PVRIG deliver inhibitory signals to T and NK cells and compete with the co-activating receptor DNAM1 for binding to PVR and PVRL2, respectively. Accordingly, TIGIT and PVRIG co-blockade was shown to synergize in enhancing anti-tumor immunity in preclinical models. PVRL2 and PVR were shown to be expressed on MM plasma cells in the bone marrow (BM). In this study, we evaluated DNAM1 axis receptor expression in the BM of patients with MM. BM mononuclear cells derived from 21 patients with MM were analyzed for the expression of PD1 and DNAM1 axis molecules by flow cytometry. Patients classified with progressed disease (PD), or complete response (CR) were treated with multiple lines of therapies including targeted therapies, chemotherapies, proteasome inhibitors. PVRIG demonstrated the highest expression among all evaluated receptors on NK (88%), NKT (81%) and CD8+ T cells (79%), significantly higher than PD1 (p50%). Additionally, the expression of PVRIG ligand, PVRL2, on BM plasma cells from 6 patients with MM was demonstrated by immuno-histochemistry and flow cytometry. A fraction of CD8+ T cells were DNAM1- and positive for PVRIG/TIGIT/PD1 (22%), suggesting the accumulation of an exhausted CD8+ T cell population in the MM tumor microenvironment. PVRIG showed significantly higher (p Citation Format: Masha Frenkel, Zoya Alteber, Ning Xu, Mingjie Li, Haiming Chen, Gady Cojocaru, James Berenson, Eran Ophir. The expression of the PVRIG/TIGIT pathway is dominant in the bone marrow of patients with multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 610.

Non-randomised trials have reported benefits of kyphoplasty in patients with cancer and vertebral compression fractures (VCFs). We aimed to assess the efficacy and safety of balloon kyphoplasty compared with non-surgical management for patients with cancer who have painful VCFs.The Cancer Patient Fracture Evaluation (CAFE) study was a randomised controlled trial at 22 sites in Europe, the USA, Canada, and Australia. We enrolled patients aged at least 21 years who had cancer and one to three painful VCFs. Patients were randomly assigned by a computer-generated minimisation randomisation algorithm to kyphoplasty or non-surgical management (control group). Investigators and patients were not masked to treatment allocation. The primary endpoint was back-specific functional status measured by the Roland-Morris disability questionnaire (RDQ) score at 1 month. Outcomes at 1 month were analysed by modified intention to treat, including all patients with data available at baseline and at 1 month follow-up. Patients in the control group were allowed to crossover to receive kyphoplasty after 1 month. This study is registered with ClinicalTrials.gov, NCT00211237.Between May 16, 2005, and March 11, 2008, 134 patients were enrolled and randomly assigned to kyphoplasty (n=70) or non-surgical management (n=64). 65 patients in the kyphoplasty group and 52 in the control group had data available at 1 month. The mean RDQ score in the kyphoplasty group changed from 17·6 at baseline to 9·1 at 1 month (mean change -8·3 points, 95% CI -6·4 to -10·2; p0·0001). The mean score in the control group changed from 18·2 to 18·0 (mean change 0·1 points; 95% CI -0·8 to 1·0; p=0·83). At 1 month, the kyphoplasty treatment effect for RDQ was -8·4 points (95% CI -7·6 to -9·2; p0·0001). The most common adverse events within the first month were back pain (four of 70 in the kyphoplasty group and five of 64 in the control group) and symptomatic vertebral fracture (two and three, respectively). One patient in the kyphoplasty group had an intraoperative non-Q-wave myocardial infarction, which resolved and was attributed to anaesthesia. Another patient in this group had a new VCF, which was thought to be device related.For painful VCFs in patients with cancer, kyphoplasty is an effective and safe treatment that rapidly reduces pain and improves function.Medtronic Spine LLC.

BACKGROUND Bortezomib, a first-in-class proteasome inhibitor, has shown clinical activity in relapsed, refractory multiple myeloma in a pivotal Phase II trial, SUMMIT. METHODS Patients received bortezomib 1.3 mg/m2 on Days 1, 4, 8, and 11 followed by a 10-day rest period for up to 8 cycles. Dexamethasone 20 mg on the day of and the day after bortezomib was permitted for suboptimal response. Extended treatment beyond 8 cycles was offered to patients whose physicians felt they would benefit from additional therapy. Follow-up was conducted in all patients for a median of 23 months, an additional 13 months from the original report. RESULTS Of 202 patients enrolled in SUMMIT, 193 were evaluable for response. Seven (4%) patients achieved a complete response, 12 (6%) achieved a nearly complete response, 34 (18%) achieved a partial response, and 14 (7%) had a minimal response while on bortezomib. The updated median duration of response to bortezomib alone was 12.7 months. The median overall time to progression for all SUMMIT patients was 7 months. For responding patients, the median time to progression was 13.9 months, whereas for those with progressive disease (PD) or who were not evaluable, the median time to progression was 1.3 months. The median overall survival (OS) for all SUMMIT patients was 17.0 months. Whereas the median OS for patients with PD or who were not evaluable was 8 months, the median OS for responding patients was not reached at 23 months of follow-up. CONCLUSIONS These data demonstrate that treatment with bortezomib results in meaningful long-term benefit for patients with relapsed and refractory myeloma. Cancer 2006. © 2006 American Cancer Society.

Leukemic B cells in chronic lymphocytic leukemia (B-CLL) typically exhibit low or undetectable surface Ig. Because the B29 (CD79b and Igβ) and mb-1 (CD79a and Igα) gene products are required for surface Ig display in the B-cell receptor complex (BCR), we analyzed the expression of these genes in B-CLL cells. The majority (83%) of the randomly selected B-CLL patient samples analyzed exhibited low or undetectable surface BCR measured by μ heavy chain and B29 expression. Levels of mb-1 mRNA in these B-CLL samples with low surface BCR were similar to those in normal B cells. Among those with decreased surface expression, B29 mRNA was not detected in half of these B-CLL samples. The remaining B-CLL samples with diminished surface BCR contained normal levels of B29 mRNA. Further analysis of cDNA clones from the majority of these latter samples contained point mutations, insertions, or deletions that were largely located in the B29 transmembrane and cytoplasmic domains. These results indicate the occurrence of somatic mutations predicted to affect B29 expression and/or function in the majority of B-CLL and suggest that these aberrations underlie the diminished surface BCR display and loss of BCR signaling characteristic of this leukemia.

Enhanced expression of the antiapoptotic gene BCL-2 may participate in chemoresistance. To ascertain if multiple myeloma cells surviving exposure to chemotherapy alter their BCL-2 expression, we treated the myeloma cell lines 8226, IM-9, and U266 as well as a primary myeloma cell culture with various injurious agents. Doxorubicin, etoposide, and hydrogen peroxide consistently induced a concentration- and time- dependent upregulation of BCL-2 expression in all myeloma target cell types assayed by flow cytometry and Western blot analysis. In contrast, serum starvation, dexamethasone, and anti-fas antibodies had no effect on expression. Enhanced expression of BCL-2 was relatively selective as treatments had no effect on expression of Ig light chains, BCL-X, or actin. An reverse transcriptase-polymerase chain reaction assay showed increased levels of BCL-2 RNA in 8226 cells as early as 4 hours after treatment with doxorubicin at a time when cell recoveries were not decreased. Thus, doxorubicin stimulates BCL-2 expression in individual 8226 cells rather than simply allowing a selected survival of high BCL- 2-expressing cells in culture. Doxorubicin-treated 8226 cells with upregulated BCL-2 expression were relatively resistant to a second exposure of doxorubicin. In addition, BCL-2-transfected IM-9 cells, with enhanced expression of BCL-2 which was comparable to that achieved by initial exposure to doxorubicin, were resistant to doxorubicin and etoposide cytotoxicity. These data suggest that exposure to chemotherapeutic agents may enhance BCL-2 expression in surviving myeloma cells and contribute to acquired chemoresistance.

Background Immunomodulatory drugs (IMiD), such as thalidomide and lenalidomide (LEN) and its newest derivative pomalidomide (POM), have shown great promise for the treatment of multiple myeloma (MM) patients (pts). POM has in vitro anti-MM potency and has shown efficacy for the treatment of relapsed/refractory (RR) MM pts. POM with dexamethasone (DEX) induces responses even for MM pts who are refractory to bortezomib (BORT) and LEN (Richardson et al, 2012). Pegylated liposomal doxorubicin (PLD) with BORT is FDA-approved for the treatment of MM pts who have received one prior therapy not containing BORT. The combination of PLD and LEN or thalidomide has shown efficacy for both RR and frontline MM pts (Offidani et al, 2006; 2007). We have also demonstrated that both the efficacy and tolerability of LEN in combination with DEX, PLD and BORT (DVD-R) may be improved by changing the doses and schedules of these drugs (Berenson et al, 2012). Based on these results, we hypothesized that the combination of POM, DEX and PLD would be effective for the treatment of RRMM pts. Thus, we conducted the first study investigating the safety and efficacy of POM in combination with intravenous (IV) DEX and PLD as a phase 1/2 trial using a modified dose, schedule and longer 28-day cycles for pts with RRMM. Methods The phase 1 portion enrolled MM pts w/progressive disease whereas those enrolled in phase 2 also had to be refractory to LEN (single-agent or in combination), as demonstrated by progressive disease while receiving their last LEN-containing regimen or relapsed within 8 weeks of their last dose of this IMiD. Pts who previously received POM treatment were ineligible. POM was administered orally on days 1-21 of a 28-day cycle, while DEX (40 mg) and PLD (5mg/m2) were both infused on days 1, 4, 8, and 11. During phase 1 enrollment, three cohorts were enrolled at 2, 3 and 4 mg doses of POM, and DEX and PLD were both administered at fixed doses. Phase 2 enrollment commenced once the MTD was established from the phase 1 portion of the study. Results As of August 1, 2015, 70 pts were screened, 68 were enrolled in the trial (with the pre-planned enrollment goal reached) and had received study drug, and a total of 50 pts were evaluable for safety and efficacy. Among all enrolled pts, 60pts discontinued treatment and 8 remain active. Pts had received a median of 4 prior treatments (range 1-18). Median number of cycles for all pts was 4 (range 1-8), with a median follow-up time of 5.5 months (range 0-22). During the phase 1 portion of the trial, the maximum tolerated dose (MTD) of POM was established at 4 mg. Enrollment of pts into the phase 2 portion of the trial began at the MTD. However, neutropenia ≥ grade 3 was observed at this dose in 10/17 (58.8%) phase 2 pts; and, as a result, the protocol was amended so that the MTD was lowered to 3 mg for all pts subsequently enrolled. Among the 57 pts enrolled in phase 2, 53% percent were refractory to LEN and steroids with or without other agents and 31% had previously received PLD. A median of 4 cycles (range, 1 to 8) were administered among the pts enrolled in phase 2. Fifty-five pts were evaluable for response as 2 pts are active but have not yet had any post-baseline disease assessment. Among all evaluable pts (n=55) enrolled in phase 2, the overall response rate (ORR) was 33% (CR= 5%, VGPR= 5% and PR=23%) and clinical benefit rate (CBR) was 47% with 11 pts (26%) showing stable disease and 5 pts (12%) demonstrating progressive disease. For all evaluable pts enrolled in phase 2, the median follow-up time was 3.6 months (range 0-12 months) and the median PFS was 4.2 months (range 0.3- 29.0+). ORR and CBR for pts in the phase 2 were higher among pts receiving POM at 3 mg (36% and 51%, respectively) than among pts receiving POM at 4 mg (25% and 37%, respectively). Pts receiving the 4 mg dose of POM experienced more toxicities resulting in discontinuations, which likely explains the lower ORR and CBR observed among pts receiving this POM dose. Common ≥ grade 3 adverse events observed throughout the trial were neutropenia (49 pts; 72.0%), lymphopenia (36 pts; 52.9%), leukopenia (33 pts; 48.5%), hyponatremia (27 pts; 39.7%), and hypokalemia (26pts; 38.2%). One pt died of grade 5 sepsis. Conclusions This phase 1/2 trial is the first evaluating POM with PLD and DEX and demonstrates that the combination of POM at 3 mg, PLD and DEX using a modified 28-day cycle schedule is safe and effective for the treatment of MM pts refractory to LEN. Disclosures No relevant conflicts of interest to declare.

The nuclear factor kappa B (NF-kappaB) family of transcription factors plays a major role in inflammation, immune and stress responses, oncogenesis, cell migration, and angiogenesis. Aberrant activation of NF-kappaB has also been shown to contribute to intrinsic and inducible drug resistance in numerous cancers, including multiple myeloma. The expression of NF-kappaB-responsive targets will vary depending on the cellular context and type of inducer. The regulation of NF-kappaB activity occurs at multiple levels involving the IkappaB kinase (IKK) complex, members of the IkappaB family, recruitment of heterologous transcription factors and coactivators by NF-kappaB, and post-translational modifications of p65. This article highlights regulatory mechanisms responsible for constitutive NF-kappaB activation and provides justification for target-based therapy for NF-kappaB in multiple myeloma.

We have assessed the specificity of antibodies from the leukemic B cells of five patients with both chronic lymphocytic leukemia and autoimmune hemolytic anemia (CLL-AHA). Leukemic cells from one patient displayed surface immunoglobulin with heavy and light chain isotypes identical to that of the patient's anti-red blood cell (RBC) antibodies, and the leukemic cells secreted antibodies in vitro with anti-RBC activity. However, in the remaining patients, the leukemic cells displayed surface immunoglobulin with light chain isotypes different from that of the patient's anti-RBC antibodies and secreted antibodies in vitro with no detectable anti-RBC activity. Thus, there are two distinct classes of CLL-AHA patients, differentiated by the presence or absence of an anti-RBC antibody-producing leukemic B cell clone. The apparent heterogeneity in the source of pathogenic anti-RBC antibodies may impact the treatment response of the two classes of CLL-AHA patients.

Previous work with continuously cultured multiple myeloma lines suggested that cytokine production by tumor cells may mediate some of the medical complications of this disease. To further investigate this issue, we assayed freshly obtained bone marrow (BM) cells from myeloma patients for the in vitro production of cytokines and the presence of cytokine RNA. Production of cytokine protein was assessed by bioassays with the aid of specific neutralizing anticytokine antibodies. These assays detected interleukin-1 (IL-1) and tumor necrosis factor (TNF) secretion by myeloma BM cells, which was significantly greater than secretion from similarly processed BM cells of control individuals. In contrast, lymphotoxin and interleukin-2 (IL-2) production could not be detected. The levels of IL-1 and TNF produced in vitro peaked at 24 hours of culture and correlated with stage and the presence (or absence) of extensive osteolytic bone disease. Northern blot analysis demonstrated the presence of IL-1 beta and TNF RNA in uncultured myeloma BM cells but no detectable IL-1 alpha or lymphotoxin RNA. In addition, the amount of cytokine RNA correlated with protein production, being significantly greater in patients' BM cells than in control marrow. These data suggest a role for IL-1 beta and/or TNF in the pathophysiology of multiple myeloma and argue against a role for lymphotoxin or IL-2.