Multiple myeloma with high adenosine deaminase expression

A 50-year-old man with immunoglobulin A type multiple myeloma (MM) was referred to our hospital after bortezomib therapy. He had high alkaline phosphatase and lactate dehydrogenase levels. Computed tomography showed osteolytic and osteoblastic bone lesions. Response to salvage chemotherapy was temporary, and he developed a right pleural effusion with high adenosine deaminase (ADA) levels. He died from bleeding associated with a pelvic bone fracture 9 months later. ADA mRNA expression and ADA secretion of the MM cells from the patient were higher than those from myeloma cell lines tested. Clinical relevance of high ADA expression in MM cells is warranted

TAK1 inhibition in myeloma

Along with the tumor progression, the bone marrow microenvironment is skewed in multiple myeloma (MM), which underlies the unique pathophysiology of MM and confers aggressiveness and drug resistance in MM cells. TGF-β-activated kinase-1 (TAK1) mediates a wide range of intracellular signaling pathways. We demonstrate here that TAK1 is constitutively overexpressed and phosphorylated in MM cells, and that TAK1 inhibition suppresses the activation of NF-κB, p38MAPK, ERK and STAT3 in order to decrease the expression of critical mediators for MM growth and survival, including PIM2, MYC, Mcl-1, IRF4, and Sp1, along with a substantial reduction in the angiogenic factor VEGF in MM cells. Intriguingly, TAK1 phosphorylation was also induced along with upregulation of vascular cell adhesion molecule-1 (VCAM-1) in bone marrow stromal cells (BMSC) in cocultures with MM cells, which facilitated MM cell-BMSC adhesion while inducing IL-6 production and receptor activator of nuclear factor κ-Β ligand (RANKL) expression by BMSC. TAK1 inhibition effectively impaired MM cell adhesion to BMSC to disrupt the support of MM cell growth and survival by BMSC. Furthermore, TAK1 inhibition suppressed osteoclastogenesis enhanced by RANKL in cocultures of bone marrow cells with MM cells, and restored osteoblastic differentiation suppressed by MM cells or inhibitory factors for osteoblastogenesis overproduced in MM. Finally, treatment with the TAK1 inhibitor LLZ1640-2 markedly suppressed MM tumor growth and prevented bone destruction and loss in mouse MM models. Therefore, TAK1 inhibition may be a promising therapeutic option targeting not only MM cells but also the skewed bone marrow microenvironment in MM

Sphingosine 1-Phosphate (S1P) in the Peritoneal Fluid Skews M2 Macrophage and Contributes to the Development of Endometriosis

Sphingosine 1-phosphate (S1P), an inflammatory mediator, is abundantly contained in red blood cells and platelets. We hypothesized that the S1P concentration in the peritoneal cavity would increase especially during the menstrual phase due to the reflux of menstrual blood, and investigated the S1P concentration in the human peritoneal fluid (PF) from 14 non-endometriosis and 19 endometriosis patients. Although the relatively small number of samples requires caution in interpreting the results, S1P concentration in the PF during the menstrual phase was predominantly increased compared to the non-menstrual phase, regardless of the presence or absence of endometriosis. During the non-menstrual phase, patients with endometriosis showed a significant increase in S1P concentration compared to controls. In vitro experiments using human intra-peritoneal macrophages (MΦ) showed that S1P stimulation biased them toward an M2MΦ-dominant condition and increased the expression of IL-6 and COX-2. An in vivo study showed that administration of S1P increased the size of the endometriotic-like lesion in a mouse model of endometriosis

CD20陰性DLBCL

A ６８-year-old woman presented with sustained fever for more than １ month and admitted due to hematemesis and systemic edema. Computed tomography scan revealed swelling of the cervical, paraaortic lymph nodes. Blood test results showed severe anemia, elevation of white blood cell count, elevation of liver enzyme and coagulopathy with high C-reactive protein. Biopsy of the right cervical lymph node showed proliferation of abnormal lymphoid cells with necrosis and hemorrhage, which are positive for CD７９α, CD３０, MUM‐１, and bcl‐６ and negative for CD２０, CD５, CD１０, ALK, CD３８, CD１３８, and EBER. Gene rearrangement of immunoglobulin heavy chain was detected in tumor cells. Bone marrow aspiration showed tumor involvement. The patient was diagnosed with de novo CD２０‐negative diffuse large B-cell lymphoma（DLBCL）stage IV B. Reduced CHOP therapy was performed under artificial respiration due to pulmonary edema and takotsubo cardiomyopathy. Although her general condition and high CRP levels temporarily improved, she died ４７ days after admission due to rapid relapse. De novo CD２０‐negative DLBCL was rare and presented with high CRP levels and rapid progression, and was thought to be clinically different from the existing DLBCL. It is imperative to elucidate molecular pathophysiology and establish new treatment strategy for de novo CD２０‐negative DLBCL

インターフェロン-γと協調したパノビノスタットによる骨髄腫細胞のPD-L1発現誘導

Immunotherapy is revolutionizing the treatment paradigm for multiple myeloma (MM). Interferon (IFN)-γ is essential for immune responses, whereas immune checkpoint molecules, such as programmed cell death-1 ligand-1 (PD-L1), mitigate the beneficial anti-tumor immune responses. As HDAC inhibitors alter the immunogenicity and anti-tumor immune responses, we here explored the regulation of PD-L1 expression in MM cells by the clinically available HDAC inhibitor panobinostat in the presence of IFN-γ. IFN-γ activated the STAT1-IRF1 pathway to upregulate PD-L1 expression in MM cells, and panobinostat was able to upregulate their PD-L1 expression without activating the STAT1-IRF1 pathway. Of note, panobinostat enhanced IFN-γR1 expression, which substantially increased the total and phosphorylated levels of STAT1 protein but reduced IRF1 protein levels through proteasomal degradation in the presence of IFN-γ. Panobinostat further enhanced the IFN-γ-mediated durable STAT1 activation in MM cells; STAT1 gene silencing abolished the PD-L1 upregulation by panobinostat and IFN-γ in combination, indicating a critical role for STAT1. These results suggest that panobinostat enhances PD-L1 expression by facilitating the IFN-γ-STAT1 pathway in a ligand-dependent manner in MM cells with ambient IFN-γ. PD-L1 upregulation should be taken into account when combining immunotherapies with panobinostat

Combination of Defucosylated AHM plus Lenalidomide

The immunomodulatory drug lenalidomide (Len) has drawn attention to potentiate antibody-dependent cellular cytotoxicity (ADCC)-mediated immunotherapies. We developed the defucosylated version (YB-AHM) of humanized monoclonal antibody against HM1.24 (CD317) overexpressed in multiple myeloma (MM) cells. In this study, we evaluated ADCC by YB-AHM and Len in combination against MM cells and their progenitors. YB-AHM was able to selectively kill via ADCC MM cells in bone marrow samples from patients with MM with low effector/target ratios, which was further enhanced by treatment with Len. Interestingly, Len also up-regulated HM1.24 expression on MM cells in an effector-dependent manner. HM1.24 was found to be highly expressed in a drug-resistant clonogenic ‘‘side population’’ in MM cells; and this combinatory treatment successfully reduced SP fractions in RPMI 8226 and KMS-11 cells in the presence of effector cells, and suppressed a clonogenic potential of MM cells in colony-forming assays. Collectively, the present study suggests that YB-AHM and Len in combination may become an effective therapeutic strategy in MM, warranting further study to target drug-resistant MM clonogenic cells

パノビノスタットとプロテアソーム阻害薬は骨髄腫細胞の増殖と生存に必須の転写因子Sp1を相乗的に標的にする

Panobinostat, a pan-deacetylase inhibitor, synergistically elicits cytotoxic activity against myeloma (MM) cells in combination with the proteasome inhibitor bortezomib. Because precise mechanisms for panobinostat’s anti-MM action still remain elusive, we aimed to clarify the mechanisms of anti-MM effects of panobinostat and its synergism with proteasome inhibitors. Although the transcription factor Sp1 was overexpressed in MM cells, the Sp1 inhibitor terameprocol induced MM cell death in parallel with reduction of IRF4 and cMyc. Panobinostat induced activation of caspase-8, which was inversely correlated with reduction of Sp1 protein levels in MM cells. The panobinostat-mediated effects were further potentiated to effectively induce MM cell death in combination with bortezomib or carfilzomib even at suboptimal concentrations as a single agent. Addition of the caspase-8 inhibitor z-IETD-FMK abolished the Sp1 reduction not only by panobinostat alone but also by its combination with bortezomib, suggesting caspase-8-mediated Sp1 degradation. The synergistic Sp1 reduction markedly suppressed Sp1-driven prosurvival factors, IRF4 and cMyc. Besides, the combinatory treatment reduced HDAC1, another Sp1 target, in MM cells, which may potentiate HDAC inhibition. Collectively, caspase-8-mediated post-translational Sp1 degradation appears to be among major mechanisms for synergistic anti-MM effects of panobinostat and proteasome inhibitors in combination

MODULATION OF TRAIL ACTION BY TAK1 INHIBITION

Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) agonists induce tumor-specific apoptosis indicating that they may be an attractive therapeutic strategy against cancers, including multiple myeloma (MM). Osteoclastogenesis is highly induced in MM, which in turn enhances MM growth, thereby forming a vicious cycle between MM tumor expansion and bone destruction. However, the effects of TRAIL on MM-enhanced osteoclastogenesis remain largely unknown. Here, we show that TRAIL induced apoptosis in MM cells, but not in osteoclasts (OCs), and that it rather facilitated receptor activator of NF-kB ligand–induced osteoclastogenesis along with upregulation of cellular FLICE inhibitory protein (c-FLIP). TRAIL did not induce death-inducing signaling complex formation in OCs, but formed secondary complex (complex II) with the phosphorylation of transforming growth factor b–activated kinase-1 (TAK1), and thus activated NF-kB signaling. c-FLIP knockdown abolished complex II formation, thus permitting TRAIL induction of OC cell death. The TAK1 inhibitor LLZ1640-2 abrogated the TRAIL-induced c-FLIP upregulation and NF-kB activation, and triggered TRAIL-induced caspase-8 activation and cell death in OCs. Interestingly, the TRAIL-induced caspase-8 activation caused enzymatic degradation of the transcription factor Sp1 to noticeably reduce c-FLIP expression, which further sensitized OCs to TRAIL-induced apoptosis. Furthermore, the TAK1 inhibition induced antiosteoclastogenic activity by TRAIL even in cocultures with MM cells while potentiating TRAIL’s anti-MM effects. These results demonstrated that osteoclastic lineage cells use TRAIL for their differentiation and activation through tilting caspase-8–dependent apoptosis toward NF-kB activation, and that TAK1 inhibition subverts TRAIL-mediated NF-kB activation to resume TRAIL-induced apoptosis in OCs while further enhancing MM cell death in combination with TRAIL