Myeloma bone disease: pathogenesis and management in the era of new anti-myeloma agents.

INTRODUCTION: Multiple myeloma (MM) is a malignancy of plasma cells with characteristic bone disease. Despite recent great strides achieved in MM treatment owing to the implementation of new anti-MM agents, MM is still incurable and bone destruction remains a serious unmet issue in patients with MM. APPROACH: In this review, we will summarize and discuss the mechanisms of the formation of bone disease in MM and the available preclinical and clinical evidence on the treatment for MM bone disease. CONCLUSIONS: MM cells produce a variety of cytokines to stimulate receptor activator of nuclear factor-κB ligand-mediated osteoclastogenesis and suppress osteoblastic differentiation from bone marrow stromal cells, leading to extensive bone destruction with rapid loss of bone. MM cells alter the microenvironment through bone destruction where they colonize, which in turn favors tumor growth and survival, thereby forming a vicious cycle between tumor progression and bone destruction. Denosumab or zoledronic acid is currently recommended to be administered at the start of treatment in newly diagnosed patients with MM with bone disease. Proteasome inhibitors and the anti-CD38 monoclonal antibody daratumumab have been demonstrated to exert bone-modifying activity in responders. Besides their anti-tumor activity, the effects of new anti-MM agents on bone metabolism should be more precisely analyzed in patients with MM. Because prognosis in patients with MM has been significantly improved owing to the implementation of new agents, the therapeutic impact of bone-modifying agents should be re-estimated in the era of these new agents.

Palmitoylated CKAP4 regulates mitochondrial functions through an interaction with VDAC2 at ER-mitochondria contact sites.

Cytoskeleton-associated protein 4 (CKAP4) is a palmitoylated type II transmembrane protein localized to the endoplasmic reticulum (ER). Here, we found that knockout (KO) of CKAP4 in HeLaS3 cells induces the alteration of mitochondrial structures and increases the number of ER-mitochondria contact sites. To understand the involvement of CKAP4 in mitochondrial functions, the binding proteins of CKAP4 were explored, enabling identification of the mitochondrial porin voltage-dependent anion-selective channel protein 2 (VDAC2), which is localized to the outer mitochondrial membrane. Palmitoylation at Cys100 of CKAP4 was required for the binding between CKAP4 and VDAC2. In CKAP4 KO cells, the binding of inositol trisphosphate receptor (IP3R) and VDAC2 was enhanced, the intramitochondrial Ca2+ concentration increased and the mitochondrial membrane potential decreased. In addition, CKAP4 KO decreased the oxidative consumption rate, in vitro cancer cell proliferation under low-glucose conditions and in vivo xenograft tumor formation. The phenotypes were not rescued by expression of a palmitoylation-deficient CKAP4 mutant. These results suggest that CKAP4 plays a role in maintaining mitochondrial functions through the binding to VDAC2 at ER-mitochondria contact sites and that palmitoylation is required for this novel function of CKAP4.This article has an associated First Person interview with the first author of the paper.

Long-term Morphological Changes of the Velum and the Nasopharynx in Patients With Cleft Palate.

OBJECTIVE: To investigate long-term morphological changes in the soft palate length and nasopharynx in patients with cleft palate. We hypothesized that there would be differences in the morphological development of the soft palate and nasopharynx between patients with and without cleft palate and that these developmental changes would negatively affect the soft palate length to pharyngeal depth ratio involved in velopharyngeal closure for patients with cleft palate. DESIGN: Retrospective, case-control study. SETTING: Institutional practice. PATIENTS: Ninety-two patients (Group F) with unilateral cleft lip, alveolus, and palate and 67 patients (Group CLA) with unilateral cleft lip and alveolus not requiring palatoplasty were included. MAIN OUTCOME MEASURES: The soft palate length, nasopharyngeal size, and soft palate length to pharyngeal depth ratio were measured via lateral cephalograms obtained at three different periods. RESULTS: Group F showed a shorter soft palate length and smaller nasopharyngeal size than Group CLA at all periods. Both these parameters increased with age, but the increase in amount was significantly less in Group F compared with that in Group CLA. The soft palate length to pharyngeal depth ratio in Group F decreased with age. CONCLUSIONS: In patients with cleft palate, the soft palate length to pharyngeal depth ratio, which is involved in velopharyngeal closure, can change with age. Less soft palate length growth and unfavorable relationship between the soft palate and nasopharynx may be masked in early childhood but can manifest later on with age.

[Primary cutaneous anaplastic large cell lymphoma with systemic progression responding to low-dose methotrexate therapy].

The standard therapies for primary cutaneous anaplastic large cell lymphoma (pcALCL) in an advanced stage remain undefined. A 71-year-old man presented with multiple erythema and nodules. He was diagnosed with lymphomatoid papulosis (LyP) through a skin biopsy from the left postauricular area. All skin lesions achieved complete response by electron beam irradiation. However, nodular lesions appeared in both inner canthi 5 months later. Histopathological evaluation of the lesional biopsy revealed dominant infiltration of CD30-positive large cells. Positron emission tomography/computed tomography revealed fluorodeoxyglucose-positive cervical and inguinal lymph node swelling and right tonsillitis, followed by the diagnosis of pcALCL and TNM classification T3bN3M0. Since the patient had severe chronic obstructive pulmonary disease and recurrent pneumonia, he received low-dose methotrexate (MTX) (15 mg/week) therapy. Low-dose MTX effectively debulked the lymphadenopathies over time without particular adverse effects. Although the standard therapies for pcALCL are not established, low-dose MTX was effective and considered safe for patients with frailty and compromised respiratory function. Further study is warranted on the pathophysiology of pcALCL after the development of LyP and mechanisms of action of low-dose MTX against LyP and pcALCL.

TAK1 is a pivotal therapeutic target for tumor progression and bone destruction 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-ß-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 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 (BMSCs) 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 BMSCs. TAK1 inhibition effectively impaired MM cell adhesion to BMSCs to disrupt the support of MM cell growth and survival by BMSCs. 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.

ARL4C is associated with initiation and progression of lung adenocarcinoma and represents a therapeutic target.

Lung adenocarcinoma is the most common histological type of lung cancer and is classified into adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IA). Atypical adenomatous hyperplasia (AAH) lesions are possible precursors to adenocarcinoma. However, the mechanism underlying the stepwise continuum of lung adenocarcinoma is unclear. In this study, the involvement of ADP-ribosylation factor (ARF)-like (ARL) 4C (ARL4C), a member of the small GTP-binding protein family, in the progression of lung adenocarcinoma and the possibility of ARL4C as a molecular target for lung cancer therapy were explored. ARL4C was frequently expressed in AAH and ARL4C expression in immortalized human small airway epithelial cells promoted cell proliferation and suppressed cell death. In addition, ARL4C was expressed with increased frequency in AIS, MIA and IA in a stage-dependent manner, and the expression was correlated with histologic grade, fluorine-18 fluorodeoxyglucose uptake and poor prognosis. An anti-sense oligonucleotide (ASO) against ARL4C (ARL4C ASO-1316) inhibited RAS-related C3 botulinum toxin substrate activity and nuclear import of Yes-associated protein and transcriptional coactivator with PDZ-binding motif, and suppressed in vitro proliferation and migration of lung cancer cells with KRAS or epidermal growth factor receptor (EGFR) mutations. In addition, transbronchial administration of ARL4C ASO-1316 suppressed orthotopic tumor formation induced by these cancer cells. Thus, ARL4C is involved in the initiation of the premalignant stage and is associated with the stepwise continuum of lung adenocarcinoma. ARL4C ASO-1316 would be useful for lung adenocarcinoma patients expressing ARL4C regardless of the KRAS or EGFR mutation.

Improved Quality of Life for Children With Beckwith-Wiedemann Syndrome Following Tongue Reduction Surgery.

Macroglossia is observed in the majority of patients with Beckwith-Wiedemann syndrome (BWS), a congenital condition with characteristic anomalies. In addition, sleep disordered breathing (SDB) associated with macroglossia has occasionally been noted in BWS patients, for which tongue reduction surgery is generally performed. However, macroglossia is related to various health problems, such as eating and articulation disorders, attention deficit disorder, enuresis, and thorax deformation, as well as aesthetic issues. Therefore, in addition to treating airway obstruction, tongue reduction surgery can also exert favorable effects on the overall quality of life (QOL) of patients. However, surgical indications for tongue reduction have yet to be established and reports on QOL assessments after surgery are rare. The OSA-18 questionnaire is used for screening SDB and is also useful for assessing the effect of tongue reduction surgery on QOL. We report a patient whose QOL was improved by tongue reduction surgery. On the basis of our patient's results, we recommend tongue reduction surgery in early childhood not only to treat SDB but also to improve QOL.

[Role of HDAC isoforms and development of treatment of multiple myeloma using isoform-specific HDAC inhibitors].

Multiple myeloma (MM), which is derived from immunoglobulin-producing plasma cells, is treated using novel agents, such as proteasome inhibitors, immunomodulatory drugs (IMiDs), and anti-MM monoclonal antibodies, which have been developed based on preclinical findings. Although these treatments have improved MM prognosis, it still remains an incurable disease. Therefore, development of novel treatment strategies is warranted. Histone deacetylases (HDACs) are a group of deacetylating enzymes that catalyze the deacetylation of histone and non-histone proteins, leading to changes in gene expression and protein function and stability. Panobinostat, a pan-HDAC inhibitor, is now clinically available in combination with bortezomib and dexamethasone for the treatment of MM. To further improve treatment strategies for MM, HDACs are thought to have potential as next-generation therapeutics because HDAC isoform-selective inhibition, but not broad HDAC inhibition, is effective in MM cells. The roles of each HDAC isoform in MM are not yet precisely defined. To maintain or augment anti-MM effects without severe adverse reactions, preclinical and clinical studies are being undertaken to elucidate the impact of each HDAC isoform on MM and develop class- or isoform-selective HDAC inhibitors in combination with other therapeutics.

Unique anti-myeloma activity by thiazolidine-2,4-dione compounds with Pim inhibiting activity.

Proviral Integrations of Moloney virus 2 (PIM2) is overexpressed in multiple myeloma (MM) cells, and regarded as an important therapeutic target. Here, we aimed to validate the therapeutic efficacy of different types of PIM inhibitors against MM cells for their possible clinical application. Intriguingly, the thiazolidine-2,4-dione-family compounds SMI-16a and SMI-4a reduced PIM2 protein levels and impaired MM cell survival preferentially in acidic conditions, in contrast to other types of PIM inhibitors, including AZD1208, CX-6258 and PIM447. SMI-16a also suppressed the drug efflux function of breast cancer resistance protein, minimized the sizes of side populations and reduced in vitro colony-forming capacity and in vivo tumourigenic activity in MM cells, suggesting impairment of their clonogenic capacity. PIM2 is known to be subject to ubiquitination-independent proteasomal degradation. Consistent with this, the proteasome inhibitors bortezomib and carfilzomib increased PIM2 protein levels in MM cells without affecting its mRNA levels. However, SMI-16a mitigated the PIM2 protein increase and cooperatively enhanced anti-MM effects in combination with carfilzomib. Collectively, the thiazolidine-2,4-dione-family compounds SMI-16a and SMI-4a uniquely reduce PIM2 protein in MM cells, which may contribute to their profound efficacy in addition to their immediate kinase inhibition. Their combination with proteasome inhibitors is envisioned.

Wnt5b-associated exosomes promote cancer cell migration and proliferation.

Wnt5b is a member of the same family of proteins as Wnt5a, the overexpression of which is associated with cancer aggressiveness. Wnt5b is also suggested to be involved in cancer progression, however, details remain unclarified. We analyzed the biochemical properties of purified Wnt5b and the mode of secretion of Wnt5b by cancer cells. Wnt5b was glycosylated at three asparagine residues and lipidated at one serine residue, and these post-translational modifications of Wnt5b were essential for secretion. Purified Wnt5b showed Dvl2 phosphorylation and Rac activation abilities to a similar extent as Wnt5a. In cultured-cell conditioned medium, Wnt5b was detected in supernatant or precipitation fractions that were separated by centrifugation at 100 000 g. In PANC-1 pancreatic cancer cells, 55% of secreted endogenous Wnt5b was associated with exosomes. Exosomes from wild-type PANC-1 cells, but not those from Wnt5b-knockout PANC-1 cells, activated Wnt5b signaling in CHO cells and stimulated migration and proliferation of A549 lung adenocarcinoma cells, suggesting that endogenous, Wnt5b-associated exosomes are active. The exosomes were taken up by CHO cells and immunoelectron microscopy revealed that Wnt5b is indeed associated with exosomes. In Caco-2 colon cancer cells, most Wnt5b was recovered in precipitation fractions when Wnt5b was ectopically expressed (Caco-2/Wnt5b cells). Knockdown of TSG101, an exosome marker, decreased the secretion of Wnt5b-associated exosomes from Caco-2/Wnt5b cells and inhibited Wnt5b-dependent cell proliferation. Exosomes secreted from Caco-2/Wnt5b cells stimulated migration and proliferation of A549 cells. These results suggest that Wnt5b-associated exosomes promote cancer cell migration and proliferation in a paracrine manner.

[Analysis of long-term survivors with cardiac AL amyloidosis].

Cardiac AL amyloidosis (CA) is generally known as a severe disease with very poor prognosis. Here we retrospectively examined seven patients with CA in our cohort who achieved long-term survival. All six patients who underwent high-dose melphalan and autologous stem cell transplantation (ASCT) survived for >3 years, whereas four patients survived for >5 years. Patients who underwent ASCT had prompt hematological responses, and five patients showed organ responses. ASCT helps to achieve a quick and deep hematological response required for long-term survival in patients with CA. New agents have been implemented for the treatment of CA. However, the risks and benefits of each treatment modality should be considered according to patient condition, thus making the best use of ASCT in combination with new agents for the treatment of CA.

A possible aid in targeted insertion of large DNA elements by CRISPR/Cas in mouse zygotes.

The CRISPR/Cas system has rapidly emerged recently as a new tool for genome engineering, and is expected to allow for controlled manipulation of specific genomic elements in a variety of species. A number of recent studies have reported the use of CRISPR/Cas for gene disruption (knockout) or targeted insertion of foreign DNA elements (knock-in). Despite the ease of simple gene knockout and small insertions or nucleotide substitutions in mouse zygotes by the CRISPR/Cas system, targeted insertion of large DNA elements remains an apparent challenge. Here the generation of knock-in mice with successful targeted insertion of large donor DNA elements ranged from 3.0 to 7.1 kb at the ROSA26 locus using the CRISPR/Cas system was achieved. Multiple independent knock-in founder mice were obtained by injection of hCas9 mRNA/sgRNA/donor vector mixtures into the cytoplasm of C57BL/6N zygotes when the injected zygotes were treated with an inhibitor of actin polymerization, cytochalasin. Successful germ line transmission of three of these knock-in alleles was also confirmed. The results suggested that treatment of zygotes with actin polymerization inhibitors following microinjection could be a viable method to facilitate targeted insertion of large DNA elements by the CRISPR/Cas system, enabling targeted knock-in readily attainable in zygotes.

Concise review: Defining and targeting myeloma stem cell-like cells.

Multiple myeloma (MM) remains incurable despite recent advances in the treatment of MM. Although the idea of MM cancer stem cells (CSCs) has been proposed for the drug resistance in MM, MM CSCs have not been properly defined yet. Besides clonotypic B cells, phenotypically distinct MM plasma cell fractions have been demonstrated to possess a clonogenic capacity, leading to long-lasting controversies regarding the cells of origin in MM or MM-initiating cells. However, MM CSCs may not be a static population and survive as phenotypically and functionally different cell types via the transition between stem-like and non-stem-like states in local microenvironments, as observed in other types of cancers. Targeting MM CSCs is clinically relevant, and different approaches have been suggested to target molecular, metabolic and epigenetic signatures, and the self-renewal signaling characteristic of MM CSC-like cells.

Survival of multiple myeloma patients aged 65-70 years in the era of novel agents and autologous stem cell transplantation. A multicenter retrospective collaborative study of the Japanese Society of Myeloma and the European Myeloma Network.

Novel agents such as thalidomide, lenalidomide and bortezomib have dramatically changed the treatment paradigm of multiple myeloma (MM). However, it is not clear whether these agents improve the prognosis of elderly patients who have undergone autologous stem cell transplantation (auto-SCT). We retrospectively analyzed the outcome of 318 newly diagnosed patients aged 65­70 years who were treated between January 1, 2004, and December 31, 2009. As initial therapy, 192 patients were treated with conventional chemotherapy,88 with novel agent-containing regimens, 21 with conventional chemotherapy plus auto-SCT and the remaining 17 with novel agents plus auto-SCT. The median progression-free survival was 19.1, 24.5, 26.8 and 35.2 months, respectively, and the 5-year overall survival (OS) was 40, 62, 63 and 87%, respectively. Initial therapy with novel agents (p < 0.001) or auto-SCT (p < 0.02) significantly improved OS compared with the group without these treatment modalities. Salvage therapy with novel agents also significantly improved survival after relapse compared with conventional chemotherapy alone (p < 0.04). In a multivariate analysis, the use of novel agents was an independent prognostic factor significantly associated with extended OS(p < 0.003). These results indicate that novel agents and auto-SCT had a major impact on OS in eligible patients in this subgroup of MM.

[Therapeutic monoclonal antibodies for hematological diseases].

Over the past decade, monoclonal antibodies (mAbs) have been demonstrated to be powerful therapeutic options for hematological diseases. MAbs exert selective therapeutic effects through binding specific molecules, which can minimize the frequency and magnitude of their adverse effects. The major mechanisms of the cytotoxic activity by mAbs against hematological malignancies are complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity (ADCC). To enhance the ADCC activity, the defucosylated version of mAbs have been developed to enhance their binding ability to Fcgamma receptor IIIa. Antibody-drug conjugates and radiolabeled mAbs are also designed to selectively kill tumor cells. Owing to the recent innovation of mAb generation and modification techniques, we can expect more benefical mAbs with diverse functions as important therapeutic strategies.