Expression of myeloid antigen in neoplastic plasma cells is related to adverse prognosis in patients with multiple myeloma

The relationship between immunohistochemical parameters, bone marrow fibrosis and bone marrow 18F-FDG uptake in multiple myeloma patients undergoing PET/CT examination

PURPOSE

The aim of this study was to determine the power of the SUVmax value obtained from 18F-FDG PET/CT in multiple myeloma (MM) patients to be able to predict immunophenotype characteristics (CD20, CD44, CD56, CD117, CD138 antigen expressions), bone marrow fibrosis, cyclin D1 oncogene, and M-protein subtypes which play a role in diagnosis-treatment and prognosis of the disease.

MATERIAL AND METHOD

The study included 54 patients with multiple myeloma who underwent PET/CT for initial staging and bone marrow biopsy. The relationship was examined in these patients between the SUVmax value measured from the iliac bone region and the immunohistochemical and bone marrow fibrosis data of the biopsy taken from the iliac bone. The Mann Whitney U test was used in the comparisons of dependent paired groups, and the Kruskal Wallis H test in the comparisons of three or more groups.

RESULTS

The median SUVmax value was 4.5 (1.9-15.6) in patients with CD117 antigen positivity, which was statistically significantly higher than the value in the patients with CD117 negativity (p = 0.031). When patient grouping was made according to the reticulin level; we found that the median SUVmax value was 4.9 (3.0-14.8) in the group with increased fibrosis and 3.6 (1.6-15.6) in the group with low fibrosis. The median SUVmax was statistically significantly higher in the group with increased fibrosis compared to the group with low fibrosis (p = 0.004). No statistically significant difference was determined in the comparisons of the SUVmax values when the patients were grouped according to the immunoglobulin heavy chain and light chain, CD20, CD44, CD56, and cyclin D1 characteristics (p > 0.05).

CONCLUSION

In MM patients who underwent PET/CT for initial staging, significant relationships were determined between FDG uptake in the bone marrow (SUVmax) and CD117 antigen and bone marrow fibrosis, which is an important prognostic factor. Higher SUVmax values were determined in the bone marrow of patients with increased fibrosis and CD117 positivity.

Discovery of a Novel Ubenimex Derivative as a First-in-Class Dual CD13/Proteasome Inhibitor for the Treatment of Cancer

The CD13 inhibitor ubenimex is used as an adjuvant drug with chemotherapy for the treatment of cancer due to its function as an immunoenhancer, but it has limitations in its cytotoxic efficacy. The proteasome inhibitor ixazomib is a landmark drug in the treatment of multiple myeloma with a high anti-cancer activity. Herein, we conjugated the pharmacophore of ubenimex and the boric acid of ixazomib to obtain a dual CD13 and proteasome inhibitor 7 (BC-05). BC-05 exhibited potent inhibitory activity on both human CD13 (IC50 = 0.13 μM) and the 20S proteasome (IC50 = 1.39 μM). Although BC-05 displayed lower anti-proliferative activity than that of ixazomib in vitro, an advantage was established in the in vivo anti-cancer efficacy and prolongation of survival time, which may be due to its anti-metastatic and immune-stimulating activity. A pharmacokinetic study revealed that BC-05 is a potentially orally active agent with an F% value of 24.9%. Moreover, BC-05 showed more favorable safety profiles than those of ixazomib in preliminary toxicity studies. Overall, the results indicate that BC-05 is a promising drug candidate for the treatment of multiple myeloma.

The surfaceome of multiple myeloma cells suggests potential immunotherapeutic strategies and protein markers of drug resistance

The myeloma surface proteome (surfaceome) determines tumor interaction with the microenvironment and serves as an emerging arena for therapeutic development. Here, we use glycoprotein capture proteomics to define the myeloma surfaceome at baseline, in drug resistance, and in response to acute drug treatment. We provide a scoring system for surface antigens and identify CCR10 as a promising target in this disease expressed widely on malignant plasma cells. We engineer proof-of-principle chimeric antigen receptor (CAR) T-cells targeting CCR10 using its natural ligand CCL27. In myeloma models we identify proteins that could serve as markers of resistance to bortezomib and lenalidomide, including CD53, CD10, EVI2B, and CD33. We find that acute lenalidomide treatment increases activity of MUC1-targeting CAR-T cells through antigen upregulation. Finally, we develop a miniaturized surface proteomic protocol for profiling primary plasma cell samples with low inputs. These approaches and datasets may contribute to the biological, therapeutic, and diagnostic understanding of myeloma.

Design, synthesis and biological evaluation of hybrid of ubenimex-fluorouracil for hepatocellular carcinoma therapy

In our previous study, we discovered a ubenimex-fluorouracil (5FU) conjugates BC-02, which displays significant in vivo anti-tumor activity, however, the instability of BC-02 in plasma limits its further development as a drug candidate. Herein, we designed and synthesized four novel ubenimex-5FU conjugates by optimizing the linkers between ubenimex and 5FU based on BC-02. Representative compound 20 is more stable than BC-02 in human plasma and displays about 100 times higher CD13 inhibitory activity than the positive control ubenimex. Meanwhile, the antiproliferative activity of 20 was comparable with 5FU in vitro. The preliminary mechanism study indicated that compound 20 exhibited significant anti-invasion and anti-angiogenesis activities in vitro. Furthermore, compound 20 obviously inhibits tumor growth and metastasis in vivo and prolong the survival time of tumor-bearing mice. Our study may have an important implication reference for the design of more druglike mutual prodrug, and compound 20 can be used as a lead compound for further design and development.

Aminopeptidase Expression in Multiple Myeloma Associates with Disease Progression and Sensitivity to Melflufen

Simple Summary

The aims of this study were to investigate aminopeptidase expression in multiple myeloma and to identify the aminopeptidases responsible for the activation of the peptide–drug conjugate melflufen in multiple myeloma. We observed a differential expression of aminopeptidases between relapsed/refractory and newly diagnosed multiple myeloma patients. A higher expression of the aminopeptidase genes XPNPEP1, RNPEP, DPP3, and BLMH in multiple myeloma plasma cells was associated with shorter patient overall survival. The peptide–drug conjugate melflufen was particularly active towards plasma cells from relapsed/refractory multiple myeloma patients. Melflufen could be hydrolyzed to its active form by the aminopeptidases LAP3, LTA4H, RNPEP, and ANPEP, all of which are expressed in multiple myeloma. These results indicate critical roles for aminopeptidases in disease progression and the activity of melflufen in multiple myeloma.

Abstract

Multiple myeloma (MM) is characterized by extensive immunoglobulin production leading to an excessive load on protein homeostasis in tumor cells. Aminopeptidases contribute to proteolysis by catalyzing the hydrolysis of amino acids from proteins or peptides and function downstream of the ubiquitin–proteasome pathway. Notably, aminopeptidases can be utilized in the delivery of antibody and peptide-conjugated drugs, such as melflufen, currently in clinical trials. We analyzed the expression of 39 aminopeptidase genes in MM samples from 122 patients treated at Finnish cancer centers and 892 patients from the CoMMpass database. Based on ranked abundance, LAP3, ERAP2, METAP2, TTP2, and DPP7 were highly expressed in MM. ERAP2, XPNPEP1, DPP3, RNPEP, and CTSV were differentially expressed between relapsed/refractory and newly diagnosed MM samples (p < 0.05). Sensitivity to melflufen was detected ex vivo in 11/15 MM patient samples, and high sensitivity was observed, especially in relapsed/refractory samples. Survival analysis revealed that high expression of XPNPEP1, RNPEP, DPP3, and BLMH (p < 0.05) was associated with shorter overall survival. Hydrolysis analysis demonstrated that melflufen is a substrate for aminopeptidases LAP3, LTA4H, RNPEP, and ANPEP. The sensitivity of MM cell lines to melflufen was reduced by aminopeptidase inhibitors. These results indicate critical roles of aminopeptidases in disease progression and the activity of melflufen in MM.

Targeted Therapy With Immunoconjugates for Multiple Myeloma

The introduction of proteasome inhibitors (PI) and immunomodulatory drugs (IMiD) has markedly increased the survival of multiple myeloma (MM) patients. Also, the unconjugated monoclonal antibodies (mAb) daratumumab (anti-CD38) and elotuzumab (anti-SLAMF7) have revolutionized MM treatment given their clinical efficacy and safety, illustrating the potential of targeted immunotherapy as a powerful treatment strategy for MM. Nonetheless, most patients eventually develop PI-, IMiD-, and mAb-refractory disease because of the selection of resistant MM clones, which associates with a poor prognosis. Accordingly, these patients remain in urgent need of new therapies with novel mechanisms of action. In this respect, mAbs or mAb fragments can also be utilized as carriers of potent effector moieties to specifically target surface antigens on cells of interest. Such immunoconjugates have the potential to exert anti-MM activity in heavily pretreated patients due to their distinct and pleiotropic mechanisms of action. In addition, the fusion of highly cytotoxic compounds to mAbs decreases the off-target toxicity, thereby improving the therapeutic window. According to the effector moiety, immunoconjugates are classified into antibody-drug conjugates, immunotoxins, immunocytokines, or radioimmunoconjugates. This review will focus on the mechanisms of action, safety and efficacy of several promising immunoconjugates that are under investigation in preclinical and/or clinical MM studies. We will also include a discussion on combination therapy with immunoconjugates, resistance mechanisms, and future developments.

Clinical effects of CD33 and MPC-1 on the prognosis of multiple myeloma treated with bortezomib

In the present study, the effects of immunophenotyping on the prognoses of patients with MM treated with bortezomib as induction therapy were investigated. A total of 118 patients with MM were examined, and the prognostic significance of the immunophenotyping and other factors were investigated. Immature and plasmablastic cell types and high-risk cytogenesis were more frequently observed in patients with CD33+ and MPC-1-. CD33+ and MPC-1- have potential as prognostic factors and correlated with lower progression-free survival and overall survival in a Kaplan-Meier analysis. Moreover, the present results demonstrated that at the relapse of disease, the percentage of CD33 increased (median 48.7%) and MPC-1 decreased (median 14.1%), respectively, therefore, both of these antigens may be associated with the refractory disease status. The present study showed that the expression of CD33 and MPC-1 in neoplastic plasma cells from patients with MM was associated with patient prognosis independent of other prognostic factors.

The Assessment of CD56 and CD117 Expressions at the Time of the Diagnosis in Multiple Myeloma Patients

Objective:

The purpose of this study is to investigate the relationship between the CD56 and CD117 expressions and the clinical and laboratory findings in multiple myeloma (MM) patients.

Materials and Methods:

Analyses of multiparametric flow cytometry data obtained from the diagnostic bone marrow aspirations of a total of 34 newly diagnosed MM patients were assessed retrospectively. CD56 and CD117 expressions of the patients were compared with their stages and clinical parameters. The staging was performed according to the International Staging System (ISS).

Results:

Of the patients, 58.8% had ISS stage 1-2 MM while 41.2% had stage 3 MM. The number of CD56-positive patients was 29, whereas the number of CD117-positive patients was 13. There was no statistical difference between the CD56 and CD117 expressions and extramedullary involvement and lytic bone lesions. The median beta-2 microglobulin level was higher in the CD117-negative group (p=0.047). CD56 and CD117 expression levels were found to be lower in advanced-stage patients than in early-stage ones (p=0.026 and p=0.017). The lactate dehydrogenase (LDH) levels were high in advanced-stage patients, and an inverse relationship was found between LDH level and CD117 expression.

Conclusion:

Our findings that the CD56 and CD117 expression levels are lower in advanced stages than earlier stages and that LDH level and CD117 expression have an inverse relationship in patients with newly diagnosed MM suggest that CD56 and CD117 expressions may be prognostic markers for MM.

Primary malignant myelomatous pleural effusion

Primary malignant myelomatous pleural effusion (PMMPE) occurs in less than 1% of patients with multiple myeloma and is diagnosed either by visualization of plasma cells on cytology or by positive flow cytometry. The presence of immature plasma cells characterized by high nucleus to cytoplasm ratio, visible nucleolus and presence of Mott cells and Russell bodies are independent poor prognostic factors. The clinician should differentiate PMMPE from secondary pleural effusion as it is associated with a significantly worse prognosis and poor overall survival.

Identification of alanyl aminopeptidase (CD13) as a surface marker for isolation of mature gastric zymogenic chief cells

Injury and inflammation in the gastric epithelium can cause disruption of the pathways that guide the differentiation of cell lineages, which in turn can cause persistent alterations in differentiation patterns, known as metaplasia. Metaplasia that occurs in the stomach is associated with increased risk for cancer. Methods for isolating distinct gastric epithelial cell populations would facilitate dissection of the molecular and cellular pathways that guide normal and metaplastic differentiation. Here, we identify alanyl aminopeptidase (CD13) as a specific surface marker of zymogenic chief cells (ZCs) in the gastric epithelium. We show that 1) among gastric epithelial cells alanyl aminopeptidase expression is confined to mature ZCs, and 2) its expression is lost en route to metaplasia in both mouse and human stomachs. With this new marker coupled with new techniques that we introduce for dissociating gastric epithelial cells and overcoming their constitutive autofluorescence, we are able to reliably isolate enriched populations of ZCs for both molecular analysis and for the establishment of ZC-derived ex vivo gastroid cultures.