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

A vicious cycle between acid sensing and survival signaling in myeloma cells : acid-induced epigenetic alteration

Myeloma (MM) cells and osteoclasts are mutually interacted to enhance MM growth while creating acidic bone lesions. Here, we explored acid sensing of MM cells and its role in MM cell response to acidic conditions. Acidic conditions activated the PI3K-Akt signaling in MM cells while upregulating the pH sensor transient receptor potential cation channel subfamily V member 1 (TRPV1) in a manner inhibitable by PI3K inhibition. The acid-activated PI3K-Akt signaling facilitated the nuclear localization of the transcription factor Sp1 to trigger the expression of its target genes, including TRPV1 and HDAC1. Consistently, histone deacetylation was enhanced in MM cells in acidic conditions, while repressing a wide variety of genes, including DR4. Indeed, acidic conditions deacetylated histone H3K9 in a DR4 gene promoter and curtailed DR4 expression in MM cells. However, inhibition of HDAC as well as either Sp1 or PI3K was able to restore DR4 expression in MM cells suppressed in acidic conditions. These results collectively demonstrate that acid activates the TRPV1-PI3K-Akt-Sp1 signaling in MM cells while inducing HDAC-mediated gene repression, and suggest that a positive feedback loop between acid sensing and the PI3K-Akt signaling is formed in MM cells, leading to MM cell response to acidic bone lesions

Anti-myeloma Activity by Thiazolidine-2,4-dione compounds

Proviral Integrations of Moloney virus 2 (PIM2) kinase 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 tumorigenic activity in MM cells, suggesting impairment of their clonogenic capacity. PIM2 is known to be subject to ubiquitination-independent proteasomal degradation. Consistently, 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

Effective impairment of myeloma cells and their progenitors by hyperthermia

Multiple myeloma (MM) remains incurable, and MM-initiating cells or MM progenitors are considered to contribute to disease relapse through their drug-resistant nature. In order to improve the therapeutic efficacy for MM, we recently developed novel superparamagnetic nanoparticles which selectively accumulate in MM tumors and extirpate them by heat generated with magnetic resonance. We here aimed to clarify the therapeutic effects on MM cells and their progenitors by hyperthermia. Heat treatment at 43°C time-dependently induced MM cell death. The treatment upregulated endoplasmic reticulum (ER) stress mediators, ATF4 and CHOP, while reducing the protein levels of Pim-2, IRF4, c-Myc and Mcl-1. Combination with the proteasome inhibitor bortezomib further enhanced ER stress to potentiate MM cell death. The Pim inhibitor SMI-16a also enhanced the reduction of the Pim-2-driven survival factors, IRF4 and c-Myc, in combination with the heat treatment. The heat treatment almost completely eradicated “side population” fractions in RPMI8226 and KMS-11 cells and suppressed their clonogenic capacity as determined by in vitro colony formation and tumorigenic capacity in SCID mice. These results collectively demonstrated that hyperthermia is able to impair clonogenic drug-resistant fractions of MM cells and enhance their susceptibility to chemotherapeutic drugs

ショウガイジ オ モツ ハハオヤ ノ セイシンテキ ケンコウド 1 ニュウヨウジキ ト ガクレイキ ノ ヒカク

本研究の目的は、障害児を持つ母親の精神的健康度の現状を明らかにし、必要な支援内容に関する指針を得ることである。 対象者はE県の通園事業、通園施設を利用する乳幼児の母親247名とE県立養護学校に通学する児童を持つ母親98名である。母親の属性(年齢、就労状況、世帯構造等)と子どもの属性(年齢、性、障害の種類と程度)および「母親の健康関連QOL」、「育児ソーシャルサポート」、母親による「父親の育児サポート認知」、「育児負担感」を調査し分析した。さらに乳幼児と児童の母親の違いについて考察した。 その結果、障害児を持つ母親のQOLを高めるためには、母親の育児負担感を軽減する必要があることが示された。また、児童の母親にとっては父親の育児サポートが育児負担感を軽減することが示唆された。乳幼児の母親のQOLは、育児ソーシャルサポート、父親のサポートによって高められることが示された。The purpose of this study is to examine the level of mental health of mothers with disabled children in order to develop guidelines for the assistance necessary to help them. The subjects were 247 mothers with disabled infants utilizing the institutes of nursery schools for disabled infants in E prefecture and 98 mothers of disabled children attending an E prefectural school for the disabled. This study examined and analyzed the attributes of mothers (age, employment status and household structure), the attributes of children (age, sex, and degree and kind of disability),the quality of life (QOL) of mothers, the social support for raising children, the level of support from fathers, and the parenting stress of mother. This study also examined the difference between mothers of children and those of infants. The results of this study indicate that to increase the QOL of mothers, parenting stress of mother need to be reduced. Moreover, this study suggests that the QOL of mothers be improved by the support of fathers and the social support for raising disabled children

ショウガイジ オ モツ ハハオヤ ノ セイシンテキ ケンコウド 2 ニュウヨウジキ ト ガクレイキ ノ ヒカク

本研究の目的は、障害児を持つ母親の精神的健康度の現状を明らかにし、必要な支援内容に関する指針を得ることである。 対象者はE県の通園事業・通園施設を利用する乳幼児の母親247名とE県立養護学校に通学する児童を持つ母親98名である。母親の属性(年齢、就労状況、世帯構造等)と、「育児ストレス・コーピング」、「育児バーンアウト」、「孤独感」について調査し分析した。さらに、同研究(I)で明らかにした他の指標(「母親の健康関連QOL」「育児ソーシャルサポート」「父親の育児サポート認知」「育児負担感」)との関連性について分析した。また、乳幼児と児童の母親の違いについて分析し、障害児を持つ母親の精神的健康度を高めるための示唆を得た。 障害児を持つ母親の健康関連QOLを高めるためには、乳幼児を持つ母親の場合、育児ソーシャルサポートが逃避的コーピングを回避し、さらに父親の育児サポートが調整的コーピング行動を惹起し、育児負担感や、育児バーンアウト、孤独感を抑制することが示された。一方、児童の母親の場合は健康関連QOLと育児ソーシャルサポートや、父親の育児サポートとは直接的な関連性がないことが明らかになった。しかし、育児負担感や育児バーンアウト、孤独感とは強い相関が認められた。また、育児負担感を軽減し育児バーンアウトを抑制するためには、父親の育児サポートが大きな要因となっていることが明らかになった。また、孤独感は児童の母親の場合は全ての尺度と関連があったが、乳幼児の場合は、父親のサポート認知とは関連が認められないという違いが見られた。The purpose of this study is to investigate condition of mental health on mothers who have disabled preschool/school age children and to provide useful information for developing the assistance guideline for them. 247 mothers who utilize nursery schools for the disabled and 98 mothers who use schools for the disabled attended this study. Questionnaire was consisted of attributes of mothers (age, employment condition, family structure), coping type to parenting stress, parenting burnout, and loneliness. After analyzing these data, following findings were found. For mothers who have preschool disabled children, parenting-related social supports prevented their negative coping (i.e. escape). And parenting support from fathers reduce their parenting stress, parenting burnout and loneliness. For mothers who have school age disabled children, parenting-related social support and parenting support from fathers do not have positive influences on their condition of mental health