Potentiation of apoptosis by histone deacetylase inhibitors and doxorubicin combination: cytoplasmic cathepsin B as a mediator of apoptosis in multiple myeloma

Background:

Although inhibitors of histone deacetylase inhibitors (HDACis) in combination with genotoxins potentiate apoptosis, the role of proteases other than caspases in this process remained elusive. Therefore, we examined the potentiation of apoptosis and related mechanisms of HDACis and doxorubicin combination in a panel of myeloma cell lines and in 25 primary myelomas.

Results:

At IC₅₀ concentrations, sodium butyrate (an HDACi) or doxorubicin alone caused little apoptosis. However, their combination potentiated apoptosis and synergistically reduced the viability of myeloma cells independent of p53 and caspase 3–7 activation. Potentiated apoptosis correlated with nuclear translocation of apoptosis-inducing factor, suggesting the induction of caspase 3- and 7-independent pathways. Consistent with this, butyrate and doxorubicin combination significantly increased the activity of cytoplasmic cathepsin B. Inhibition of cathepsin B either with a small-molecule inhibitor or downregulation with a siRNA reversed butyrate- and doxorubicin-potentiated apoptosis. Finally, ex vivo, clinically relevant concentrations of butyrate or SAHA (suberoylanilide hydroxamic acid, vorinostat, an HDACi in clinical testing) in combination with doxorubicin significantly (P<0.0001) reduced the survival of primary myeloma cells.

Conclusions:

Cathepsin B has a prominent function in mediating apoptosis potentiated by HDACi and doxorubicin combinations in myeloma. Our results support a molecular model of lysosomal–mitochondrial crosstalk in HDACi- and doxorubicin-potentiated apoptosis through the activation of cathepsin B.     

多发性骨髓瘤药物治疗的新进展

多发性骨髓瘤（MM）是常见的血液系统肿瘤，但用传统和大剂量化疗仍不能治愈。近年来研制了许多新药或发现了许多药物的新用途，如沙利度胺（thalidomide）及其衍生物、蛋白酶体抑制剂、砷剂等，与传统的MP、VAD方案相比具有更强的缓解率，给我们的临床工作带来巨大帮助。     

Bortezomib in multiple myeloma: systematic review and clinical considerations

We conducted a systematic review to determine the appropriate use of bortezomib alone or in combination with other agents in patients with multiple myeloma (mm). We searched medline, embase, the Cochrane Library, conference proceedings, and the reference lists of included studies. We analyzed randomized controlled trials and systematic reviews if they involved adult mm patients treated with bortezomib and if they reported on survival, disease control, response, quality of life, or adverse effects.Twenty-six unique studies met the inclusion criteria. For patients with previously untreated mm and for candidates for transplantation, we found a statistically significant benefit in time to progression [hazard ratio (hr): 0.48, p < 0.001; and hr: 0.63, p = 0.006, respectively] and a better response with a bortezomib than with a non-bortezomib regimen (p < 0.001). Progression-free survival was longer with bortezomib and thalidomide than with thalidomide alone (p = 0.01). In non-candidates for transplantation, a significant benefit in overall survival was observed with a bortezomib regimen (hr compared with a non-bortezomib regimen: 0.61; p = 0.008), and in transplantation candidates receiving bortezomib, the response rate was improved after induction (p = 0.004) and after a first transplant (p = 0.016).In relapsed or refractory mm, overall survival (p = 0.03), time to progression (hr: 1.82; p = 0.000004), and progression-free survival (hr: 1.69; p = 0.000026) were significantly improved with bortezomib and pegylated liposomal doxorubicin (compared with bortezomib alone), and bortezomib monotherapy was better than dexamethasone alone (hr: 0.77; p = 0.027). Bortezomib combined with thalidomide and dexamethasone was better than either bortezomib monotherapy or thalidomide with dexamethasone (p < 0.001).In previously untreated or in relapsed or refractory mm patients, bortezomib-based therapy has improved disease control and, in some patients, overall survival.     

Oral ixazomib maintenance therapy in multiple myeloma

Continuous therapy has proven to be an effective therapeutic strategy to improve the outcome of both young and elderly multiple myeloma patients. Remarkably, lenalidomide and bortezomib showed to play a crucial role in this setting due to their safety profile allowing long-term exposure. Ixazomib, the first oral proteasome inhibitor to be evaluated in multiple myeloma, exerts substantial anti-myeloma activity as a single agent and particularly in combination with immunomodulatory drugs and it may be an attractive option for maintenance therapy. Here we address the issue of maintenance therapy as part of a therapeutic approach of multiple myeloma patients focusing on the potential role of ixazomib.     

Increased resistance to proteasome inhibitors in multiple myeloma mediated by cIAP2 - implications for a combinatorial treatment

Despite the introduction of new treatment options for multiple myeloma (MM), a majority of patients relapse due to the development of resistance. Unraveling new mechanisms underlying resistance could lead to identification of possible targets for combinatorial treatment. Using TRAF3 deleted/mutated MM cell lines, we evaluated the role of the cellular inhibitor of apoptosis 2 (cIAP2) in drug resistance and uncovered the plausible mechanisms underlying this resistance and possible strategies to overcome this by combinatorial treatment. In MM, cIAP2 is part of the gene signature of aberrant NF-κB signaling and is heterogeneously expressed amongst MM patients. In cIAP2 overexpressing cells a decreased sensitivity to the proteasome inhibitors bortezomib, MG132 and carfilzomib was observed. Gene expression analysis revealed that 440 genes were differentially expressed due to cIAP2 overexpression. Importantly, the data imply that cIAPs are rational targets for combinatorial treatment in the population of MM with deleted/mutated TRAF3. Indeed, we found that treatment with the IAP inhibitor AT-406 enhanced the anti-MM effect of bortezomib in the investigated cell lines. Taken together, our results show that cIAP2 is an important factor mediating bortezomib resistance in MM cells harboring TRAF3 deletion/mutation and therefore should be considered as a target for combinatorial treatment.     

Choosing treatment options for patients with relapsed/refractory multiple myeloma

Multiple myeloma (MM) is a clonal plasma cell disorder that is still incurable using conventional treatments. Over the last decade, advances in front-line therapy have led to an increase in survival, but there are still some doubts in the case of relapsed/refractory disease. We searched the PubMed database for articles on treatment options for patients with relapsed/refractory MM published between 1996 and 2013. These treatments included hematopoietic cell transplantation (HCT), rechallenges using previous chemotherapy regimens, and trials of new regimens. The introduction of new agents such as the immunomodulatory drugs (IMIDs) thalidomide and lenalidomide, and the first-in-its-class proteasome inhibitor bortezomib, has greatly improved clinical outcomes in patients with relapsed/refractory MM, but not all patients respond and those that do may eventually relapse or become refractory to treatment. The challenge is therefore to select the optimal treatment for each patient by balancing efficacy and toxicity. To do this, it is necessary to consider disease-related factors, such as the quality and duration of responses to previous therapies, and the aggressiveness of the relapse, and patient-related factors such as age, comorbidities, performance status, pre-existing toxicities and cytogenetic patterns. The message from the trials reviewed in this article is that the new agents may be used to re-treat relapsed/refractory disease, and that the sequencing of their administration should be modulated on the basis of the various disease and patient-related factors. Moreover, our understanding of the pharmacology and molecular action of the new drugs will contribute to the possibility of developing tailored treatment.     

Serum exosomal microRNAs as novel biomarkers for multiple myeloma

Accumulating studies have focused on circulating microRNAs, which might be potential biomarkers for different malignancies. The aim of this study was to investigate the potential of serum exosomal microRNAs to be novel serum biomarkers for smouldering myeloma (SMM) or even multiple myeloma (MM). The levels of serum exosomal microRNAs and serum circulating microRNAs were measured in healthy individuals and patients with SMM (n = 20) or MM (n = 20). Serum exosomal microRNAs and serum circulating microRNAs were extracted from serum, and the expression levels of selected microRNAs were quantified by real‐time polymerase chain reaction (PCR). The levels of serum exosome‐derived miR‐20a‐5p, miR‐103a‐3p, and miR‐4505 were significantly different among patients with MM, patients with SMM, and healthy individuals, while there were differences in the levels of let‐7c‐5p, miR‐185‐5p, and miR‐4741 in patients with MM relative to those in SMM patients or healthy controls. Additionally, a significant correlation was rarely found between the levels of serum and exosomal microRNAs. This study shows that serum exosomal microRNAs can be used independently as novel serum biomarkers for MM.     

Long-term survival after surgical intervention for bone disease in multiple myeloma.

BACKGROUND: We describe the surgical treatment, outcome and long-term survival of patients with multiple myeloma (MM) in response to conventional (CC) or high-dose (HDT) chemotherapy. PATIENTS AND METHODS: Eighty-four patients diagnosed with MM were recruited for the study (51 male, 33 female; median age 62 years) and consecutively surgically treated in a single institution during a 12-year period. The main end point of the study was overall survival after surgery. Cox regression analysis was used to estimate the effect of factors that may predict survival. RESULTS: Spinal surgery was performed in 54 cases, and 30 patients were surgically treated at the extremities. The post-surgical complication rate was low (17%; 14/84 patients). The median overall survival time was 47 months. Patients receiving HDT had a longer 5-year overall survival rate than patients receiving CC (51% versus 33%). Univariate predictors of mortality included age >65 years [risk ratio (RR) 1.62; P=0.023], osteolyses in long weight-bearing bones (RR 2.23; P=0.007) and an elevated C-reactive protein level >5 mg/l (RR 1.82; P=0.016); the latter remained significant as a predictor in multivariate analysis (RR 2.66; P=0.0209). CONCLUSIONS: Given the high number of patients reaching 5-year overall survival and the low post-surgery complication rate, surgery should pursue a long-term stable reconstruction of the affected bone.     

Differential activity of MEK and ERK inhibitors in BRAF inhibitor resistant melanoma

Acquired resistance to BRAF inhibitors often involves MAPK re‐activation, yet the MEK inhibitor trametinib showed minimal clinical activity in melanoma patients that had progressed on BRAF‐inhibitor therapy. Selective ERK inhibitors have been proposed as alternative salvage therapies. We show that ERK inhibition is more potent than MEK inhibition at suppressing MAPK activity and inhibiting the proliferation of multiple BRAF inhibitor resistant melanoma cell models. Nevertheless, melanoma cells often failed to undergo apoptosis in response to ERK inhibition, because the relief of ERK‐dependent negative feedback activated RAS and PI3K signalling. Consequently, the combination of ERK and PI3K/mTOR inhibition was effective at promoting cell death in all resistant melanoma cell models, and was substantially more potent than the MEK/PI3K/mTOR inhibitor combination. Our data indicate that a broader targeting strategy concurrently inhibiting ERK, rather than MEK, and PI3K/mTOR may circumvent BRAF inhibitor resistance, and should be considered during the clinical development of ERK inhibitors.     

多发性骨髓瘤综合治疗现状与进展

多发性骨髓瘤（MM）是浆细胞克隆增生性恶性肿瘤,其治疗效果较差,迄今仍视为不可治愈的疾病。近年来着眼于MM细胞内信号通路、骨髓微环境及二者的相互作用,MM的治疗有了很大进展。该文综述了MM的化学治疗、造血干细胞移植、生物治疗、支持治疗及免疫治疗现状及其进展。     

多发性骨髓瘤患者血浆可溶性Fas水平检测及其临床意义

目的探讨多发性骨髓瘤患者血浆可溶性Fas(sFas)水平变化及其临床意义.方法用酶联免疫吸附试验法(ELISA)检测28例多发性骨髓瘤患者及25例正常对照血浆sFas值,并与多发性骨髓瘤患者骨髓涂片中骨髓瘤细胞数作相关分析.同时测定其中6例多发性骨髓瘤患者化疗前后sFas水平.结果多发性骨髓瘤患者sFas水平显著高于正常对照组[(10.36±6.87)μg/L,vs(5.58±2.78)μg/L,P＜0.01].其中6例多发性骨髓瘤患者化疗前sFas水平显著高于化疗后完全缓解时(P＜0.01).此外,骨髓涂片中骨髓瘤细胞数高者(≥15%)sFas水平显著高于骨髓瘤细胞数低者(＜15%)[(13.86±7.10)μg/L,vs(6.36士3.34)μg/L,P＜0.01].结论提示血浆sFas 水平升高与多发性骨髓瘤的发生发展可能有关.     

Bortezomib in combination with conventional chemotherapeutic agents for multiple myeloma compared with bortezomib alone

BACKGROUND: Recent studies have demonstrated synergy between bortezomib and a number of conventional cytotoxic agents. This study examined whether or not the speed of the response, progression and safety from a combination treatment of bortezomib with common chemotherapeutic drugs is superior to bortezomib monotherapy. METHODS: Fifty-seven patients with relapsed, refractory multiple myeloma (MM) who had received at least two cycles of treatment including bortezomib were enrolled in this study. The median age was 56 (35-79) years and 49.1% were male. Thirty-two patients were treated with bortezomib alone and 25 were treated with chemotherapeutic agents that were given in combination with bortezomib. The monoclonal immunoglobulin (mIg) or free light chain (FLC) concentrations were determined in the sera before and after two cycles of bortezomib treatment. The adverse events were assessed and graded according to the NCI Common Toxicity Criteria (version 2.0). RESULTS: Thirty-one of the 57 patients (54.4%) attained an early objective response (EOR) after the second bortezomib treatment, defined as a >/=50% decrease in the serum mIg or FLC concentration. Improvements in the response were observed when common chemotherapeutic agents were added to bortezomib monotherapy. In patients who received bortezomib combined with chemotherapeutic agents, 19 out of 25 patients (76%) showed an EOR, whereas 12 out of 32 patients (37.5%) given bortezomib monotherapy achieved an EOR after the second cycle of bortezomib treatment (P = 0.004); the median decrease from the baseline in the paraprotein level was 74.6 +/- 5.9 and 39.7 +/- 4.2%, respectively (P = 0.003). A statistically significant elevation of serum lactic dehydrogenase (P = 0.007) and alkaline phosphatase (P = 0.027) from baseline within two cycles of bortezomib treatment was observed in responding patients. With the combination treatment, peripheral neuropathy of >/=Grade II occurred in 12 out of 25 patients (48%) compared with 12 of 32 (37.5%) in those given bortezomib alone (P = 0.589). The median time to progression of disease was similar in the two groups (359 +/- 43.5 versus 365 +/- 103.5, P = 0.688). The multivariate Cox regression model showed that a high serum albumin and low beta2-microglobulin are favorable factors for the progression-free survival following bortezomib treatment. CONCLUSIONS: Bortezomib in combination with common chemotherapeutic agents is more active in the treatment of relapsed, refractory MM than with bortezomib alone. However, more effective post-bortezomib treatment is needed to reduce the rate of disease progression particularly in patients with high tumor burden.     

Management of adverse events induced by next-generation immunomodulatory drug and proteasome inhibitors in multiple myeloma

Introduction: In the last decade the introduction of novel agents has strongly improved multiple myeloma prognosis by doubling median overall survival. Unfortunately disease relapse is very common and patients may become refractory to previous drugs. Therefore, new therapeutic strategies are urgently needed.

Areas covered: We have reviewed the available data on next generation novel agents, particularly immunomodulatory drug pomalidomide and proteasome inhibitors carfilzomib and ixazomib, the latter being the first-in-class orally available. We focused on adverse events associated with such agents and described how they should be managed. The main grade ≥3 adverse events correlated with these drugs are hematologic, myelosuppression-related and reversible; non-hematologic grade ≥3 toxicities are less frequent, with an incidence of <10%.

Expert commentary: These agents showed to have a good tolerability. The great majority of adverse events are easily manageable with dose-adjustment and appropriate treatment, and drug discontinuation is not frequent. Favorable safety profile and high efficacy, especially in combination, confer to these drugs a central role in development of new lines of therapy against multiple myeloma. Further investigation is certainly needed to determine the best combinations including these agents.     

核素骨显像在多发性骨髓瘤疗效评价中的应用

Objective:To investigate the value of radionuclide whole-body bone imaging on monitoring chemotherapeutic effects for multiple myeloma(MM).Methods:Sixty patients were included.Twenty nine cases received CTD(thalidomide 100-200 mg/d;cyclophosphamide 200-300 mg/m2/d,1-4 days,every 4 weeks;and dexamethasone 20-40 mg/d,1-4 days,every 4 weeks);Thirty cases received VAD(vincristine 0.4 mg/d,1-4 days,every 4 weeks;adriamycin 10 mg/d,1-4 days,every 4 weeks;dexamethasone 40 mg/d,1-4 days,every 4 weeks).Radionuclide bone imagings were performed in all patients before chemotherapy,six months,twelve months and eighteen months after chemotherapy.The correlation of chemothera-peutic effects between CTD and VAD were analyzed.Results:One hundred and seventy nine bone lesions were visualized by bone scintigraphy before CTD treatment.Eighteen months after CTD chemotherapy,it was observed by bone scintigraphy that 39/179(21.78%) lesions disappeared,112/179(62.57%) improved,and 28/179(15.64%) had no change.One hundred and ninety one bone lesions were showed by bone imaging before VAD treatment,36/191(18.84%) lesions disappeared,eighteen months after chemotherapy,103/191(53.92%) improved,and 52/191(27.22%) had no change.The significant difference was observed in locations of MM induced bone lesions treated with CTD(H = 8.23,P < 0.05) and VAD(H = 11.18,P < 0.05).A significant chemotherapeutic sensitivity in detecting MM induced lesions in ribs was found compared with other bone lesions.The chemotherapeutic effect of CTD was statistically significant than that of VAD(U = 2.17,P < 0.05).Conclusion:Radionuclide whole-body bone imaging has great value in monitoring chemotherapeutic effects for MM.     

亚砷酸对多发性骨髓瘤及p38通路的作用

多发性骨髓瘤（MM）是B细胞分化终末阶段的恶性血液病。尽管新药的研发和应用明显地提高了MM的治疗效果,但是复发、耐药等的频繁发生使得MM仍不可治愈。目前应用亚砷酸治疗MM受到广泛关注。亚砷酸可通过多种分子机制产生抗MM的效应,且其单药及联合方案均得到一定效果。但是,治疗过程中耐药性的产生较大地削减了亚砷酸的治疗效应,而近来研究显示p38通路的活化在亚砷酸引发的骨髓瘤细胞耐药性中发挥至关重要的作用。因此,本文就亚砷酸抗MM机制及p38通路在其中的作用进行综述,以期提高亚砷酸治疗MM的效果,为MM的治疗提供新的思路。     

Novel inhibitors are cytotoxic for myeloma cells with NFkB inducing kinase-dependent activation of NFkB

NFkB activity is critical for survival and proliferation of normal lymphoid cells and many kinds of B-cell tumors, including multiple myeloma (MM). NFkB activating mutations, which are apparent progression events, enable MM tumors to become less dependent on bone marrow signals that activate NFkB. Mutations that activate NFkB-inducing kinase (NIK) protein are the most prevalent among the many kinds of NFkB mutations in MM tumors. NIK is the main activating kinase of the alternative NFkB pathway, although over-expression of NIK also can activate the classical pathway. Two NIK inhibitors and an isomeric control were tested with human myeloma cell lines. These specific NIK inhibitors are selectively cytotoxic for cells with NIK-dependent activation of NFkB. Combination therapy targeting NIK and IKKbeta (as a main kinase of the classical NFkB pathway) represents a promising treatment strategy in MM. NIK inhibitors can also be useful tool for assessing the role of NIK and alternative NFkB pathway in different cells.     

以脑膜肿瘤为表现的多发性骨髓瘤

目的：探讨伴有中枢神经系统（central nervous system,CNS）累及的多发性骨髓瘤（MM）的临床特征、相关高危因素和治疗。方法：报告1例以多发脑膜肿瘤为首发表现的MM并结合文献进行复习。结果：患者为年轻男性,头痛伴全身骨痛,贫血、血小板减少,伴有高钙血症和肾功能异常,头颅MRI示多发脑膜肿瘤,胸部CT示胸膜不规则增厚,骨髓象以原浆细胞为主,脑脊液涂片可见浆细胞,血清IgG水平明显增高,轻链测定κ链明显异常,免疫固定电泳示IgG和κ链条带阳性,染色体检查示复杂核型和数量异常,患者生存期不足1月。结论：MM伴CNS浸润少见,其高危相关因素包括染色体异常、原浆细胞形态和伴有其他髓外病变。有效的治疗方法尚不明确,预后较差。治疗可采取鞘注药物、全身化疗和颅脑放疗以及造血干细胞移植,所有的治疗方案应包括颅脑放疗。     

冒烟型骨髓瘤的研究进展

第21届欧洲血液学会年会在多发性骨髓瘤的基础研究、疾病诊治方面都取得了令人振奋的进展.年会上特别将冒烟型骨髓瘤作为一个专题来讲解,从其定义到进展的高危因素以及当前对冒烟型骨髓瘤理念的转变作了详细的阐述.