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Bortezomib (bort) is an effective therapeutic agent for multiple myeloma (MM) patients, however, the majority of patients develop drug resistance. Autophagy, a highly conserved process that recycles cytosol or entire organelles via lysosomal activity, is essential for the survival, homeostasis and drug resistance in MM. Growing evidence has highlighted the E3 ligase tripartite motif-containing protein 21 (TRIM21) not only interacts with multiple autophagy regulators but also participates in drug resistance in various cancers. However, to date, the direct substrates and additional roles of TRIM21 in MM remain unknown. In this study, we demonstrated that low TRIM21 expression was a factor for relapse in MM. TRIM21 knockdown (KD) made MM cells more resistant to bort, while TRIM21 overexpression (OE) resulted in increased MM sensitivity to bort. Proteomic and phospho-proteomic studies of TRIM21 KD MM cells showed bort resistance was associated with increased oxidative stress and elevated pro-survival autophagy. Our results provided that TRIM21 KD MM cell lines induced pro-survival autophagy after bort treatment, and suppressing autophagy by 3-methyladenine treatment or by the short hairpin RNA of ATG5 restored bort sensitivity. Indeed, autophagy-related gene 5 (ATG5) expression was increased and decreased by TRIM21 KD and OE, respectively. TRIM21 affected autophagy by ubiquitinating ATG5 through K48 for proteasomal degradation. Importantly, we confirmed that TRIM21 could potentiate the anti-myeloma effect of bort through in vitro and in vivo experiments. Overall, our findings define the key role for TRIM21 in MM bort resistance and provide the basis for a novel targeted therapeutic approach.

Extramedullary relapse of multiple myeloma (MM) is often resistant to existing treatments, and has an extremely poor prognosis, but our understanding of extramedullary relapse is still limited. The incidence, clinical characteristics, impact on the prognosis of extramedullary relapse, and the risk factors for extramedullary relapse in NDMM patients were analyzed. Among the 471 NDMM patients, a total of 267 patients had disease relapse during follow-up, including 64 (24.0%) patients with extramedullary relapse. Extramedullary relapse was more common in patients with younger age, IgD subtype, elevated LDH, extensive osteolytic lesions, extramedullary involvement, and spleen enlargement at the time of MM diagnosis. Survival analysis showed that extramedullary relapse patients had significantly worse median OS than patients with relapse but without extramedullary involvement (30.8 months vs. 53.6 months, p = 0.012). Multivariate analysis confirmed that elevated LDH (OR = 2.09, p = 0.023), >2 osteolytic lesions (OR = 3.70, p < 0.001), extramedullary involvement (OR = 3.48, p < 0.001) and spleen enlargement (OR = 2.27, p = 0.011) at the time of MM diagnosis were independent risk factors for extramedullary relapse in NDMM patients. Each of the above four factors was assigned a value of 1 to form the extramedullary relapse prediction score, and the 3-year extramedullary relapse rates of patients in the 0–2 and 3–4 score groups were 9.0 % and 76.7 %, respectively. This study suggested that extramedullary relapse was associated with poor clinical characteristics and poor prognosis in NDMM patients. The extramedullary relapse prediction score model composed of LDH, osteolytic lesions, extramedullary involvement and spleen enlargement has a better ability to predict extramedullary relapse than the existing ISS and R-ISS stages.

Background Multiple myeloma (MM) is the second most common hematologic malignancy with almost all patients eventually having relapse or refractory MM (RRMM), thus novel drugs or combination therapies are needed for improved prognosis. Chidamide and venetoclax, which target histone deacetylase and BCL2, respectively, are two promising agents for the treatment of RRMM. Results Herein, we found that chidamide and venetoclax synergistically exert an anti-myeloma effect in vitro in human myeloma cell lines (HMCLs) with a combination index (CI) L downregulation and BIM upregulation, and the latter protein was proved to play a critical role in sensitizing HMCLs to co-treatment. Conclusion In conclusion, these results proved the high therapeutic potential of venetoclax and chidamide combination in curing MM, representing a potent and alternative salvage therapy for the treatment of RRMM.

Background Multiple myeloma (MM) is the second most common hematologic malignancy with almost all patients eventually having relapse or refractory MM (RRMM), thus novel drugs or combination therapies are needed for improved prognosis. Chidamide and venetoclax, which target histone deacetylase and BCL2, respectively, are two promising agents for the treatment of RRMM. Results Herein, we found that chidamide and venetoclax synergistically exert an anti-myeloma effect in vitro in human myeloma cell lines (HMCLs) with a combination index (CI) L downregulation and BIM upregulation, and the latter protein was proved to play a critical role in sensitizing HMCLs to co-treatment. Conclusion In conclusion, these results proved the high therapeutic potential of venetoclax and chidamide combination in curing MM, representing a potent and alternative salvage therapy for the treatment of RRMM.

N6-methyladenosine (m6A), an internal modification in mRNA, plays a critical role in regulating gene expression. Dysregulation of m6A modifiers promotes oncogenesis through enzymatic functions that disrupt the balance between the deposition and removal of m6A modification on critical transcripts. However, the roles of mRNA m6A in multiple myeloma (MM) are poorly understood. The present study showed that RNA demethylase ALKBH5 was overexpressed in MM and associated with a poor prognosis in MM patients. Knocking down ALKBH5 induced apoptosis and inhibited the growth of MM cells in vitro. Xenograft models and gene set enrichment analysis with patient transcriptome datasets also supported the oncogenic role of ALKBH5 in MM. Mechanistic studies showed that ALKBH5 exerted tumorigenic effects in myeloma in an m6A-dependent manner, and TNF receptor-associated factor 1 (TRAF1) was a critical target of ALKBH5. Specifically, ALKBH5 regulated TRAF1 expression via decreasing m6A abundance in the 3'-untranslated region (3'-UTR) of TRAF1 transcripts and enhancing TRAF1 mRNA stability. As a result, ALKBH5 promoted MM cell growth and survival through TRAF1-mediated activation of NF-κB and MAPK signaling pathways. Collectively, our data demonstrated that ALKBH5 played a critical role in MM tumorigenesis and suggested that ALKBH5 could be a novel therapeutic target in MM.

E3 ubiquitin ligases primarily determine the substrate specificity of the ubiquitin‐proteasome system and play an essential role in the resistance to bortezomib in multiple myeloma (MM). Neural precursor cell‐expressed developmentally downregulated gene 4‐1 (NEDD4‐1, also known as NEDD4) is a founding member of the NEDD4 family of E3 ligases and is involved in the proliferation, migration, invasion and drug sensitivity of cancer cells. In the present study, we investigated the role of NEDD4‐1 in MM cells and explored its underlying mechanism. Clinically, low NEDD4‐1 expression has been linked to poor prognosis in patients with MM. Functionally, NEDD4‐1 knockdown (KD) resulted in bortezomib resistance in MM cells in vitro and in vivo. The overexpression (OE) of NEDD4‐1, but not an enzyme‐dead NEDD4‐1‐C867S mutant, had the opposite effect. Furthermore, the overexpression of NEDD4‐1 in NEDD4‐1 KD cells resensitized the cells to bortezomib in an add‐back rescue experiment. Mechanistically, pAkt‐Ser473 levels and Akt signaling were elevated and decreased by NEDD4‐1 KD and OE, respectively. NEDD4‐1 ubiquitinated Akt and targeted pAkt‐Ser473 for proteasomal degradation. More importantly, the NEDD4‐1 KD‐induced upregulation of Akt expression sensitized MM cells to growth inhibition after treatment with an Akt inhibitor. Collectively, our results suggest that high NEDD4‐1 levels may be a potential new therapeutic target in MM., What's new? While multiple myeloma (MM) remains an incurable disease, therapeutic advances have greatly improved its clinical management. Among the agents most effective against MM is the proteasome inhibitor bortezomib, though many patients eventually develop drug resistance. Here, decreased expression of the tumor suppressor NEDD4‐1 was found to serve a key role in modulating MM sensitivity to bortezomib. Reduced NEDD4‐1 expression was associated with increased PTEN/PI3K/Akt signaling and tumor growth. Experiments showed that NEDD4‐1 normally binds directly to Akt, enhancing its ubiquitination and thereby exerting anti‐MM effects. The data warrant further investigation of NEDD4‐1 reactivation as a novel therapeutic strategy for MM.

The interaction of multiple myeloma (MM) cells with macrophages (MΦs) contributes to the pathophysiology of MM. We previously showed that IL-32 is overexpressed in MM patients. The present study was designed to explore the clinical significance of IL-32 in MM and to further elucidate the mechanisms underlying the IL-32-mediated immune function of MΦs. Our results showed that high IL-32 expression in MM patients was associated with more advanced clinical stage. RNA-sequencing revealed that IL-32γ significantly induced the production of the immunosuppressive molecule indoleamine 2,3-dioxygenase (IDO) in MΦs, and this effect was verified by qRT-PCR, western blotting, and immunofluorescence. Furthermore, MM cells with IL-32-knockdown showed a reduced ability to promote IDO expression. As a binding protein for IL-32, proteinase 3 (PR3) was universally expressed on the surfaces of MΦs, and knockdown of PR3 or inhibition of the STAT3 and NF-κB pathways hindered the IL-32γ-mediated stimulation of IDO expression. Finally, IDO-positive IL-32γ-educated MΦs inhibited CD4+ T cell proliferation and IL-2, IFN-γ, and TNF-α production. Taken together, our results indicate that IL-32γ derived from MM cells promotes the immunosuppressive function of MΦs and is a potential target for MM treatment.

Extracting information from unstructured clinical text is a fundamental and challenging task in medical informatics. Our study aims to construct a natural language processing (NLP) workflow to extract information from Chinese electronic dental records (EDRs) for clinical decision support systems (CDSSs). We extracted attributes, attribute values, and tooth positions based on an existing ontology from EDRs. A workflow integrating deep learning with keywords was constructed, in which vectors representing texts were unsupervised learned. Specifically, we implemented Sentence2vec to learn sentence vectors and Word2vec to learn word vectors. For attribute recognition, we calculated similarity values among sentence vectors and extracted attributes based on our selection strategy. For attribute value recognition, we expanded the keyword database by calculating similarity values among word vectors to select keywords. Performance of our workflow with the hybrid method was evaluated and compared with keyword-based method and deep learning method. In both attribute and value recognition, the hybrid method outperforms the other two methods in achieving high precision (0.94, 0.94), recall (0.74, 0.82), and F score (0.83, 0.88). Our NLP workflow can efficiently structure narrative text from EDRs, providing accurate input information and a solid foundation for further data-based CDSSs.

Venetoclax has been approved by the United States Food and Drug Administration since 2016 as a monotherapy for treating patients with relapsed/refractory chronic lymphocytic leukemia having 17p deletion. It has led to a breakthrough in the treatment of hematologic malignancies in recent years. However, unfortunately, resistance to venetoclax is inevitable. Multiple studies confirmed that the upregulation of the anti-apoptotic proteins of the B-cell lymphoma 2 (BCL2) family mediated by various mechanisms, such as tumor microenvironment, and the activation of intracellular signaling pathways were the major factors leading to resistance to venetoclax. Therefore, only targeting BCL2 often fails to achieve the expected therapeutic effect. Based on the mechanism of resistance in specific hematologic malignancies, the combination of specific drugs with venetoclax was a clinically optional treatment strategy for overcoming resistance to venetoclax. This study aimed to summarize the possible resistance mechanisms of various hematologic tumors to venetoclax and the corresponding clinical strategies to overcome resistance to venetoclax in hematologic malignancies.

Qualified diagrams of removable partial denture (RPD) designs created by dentists provide technicians with clear and dynamic information. Generating RPD design in the clinical decision support system (CDSS) can be achieved by producing the RPD design in a textual format and then transferring the design onto diagrams. The drawing of RPD diagrams automatically and efficiently for the given textual designs is still under investigation. A new workflow consisting of three major steps is developed to produce and visualize two-dimensional RPD design diagrams. Annotations and orientations of teeth are established from the base maps in the first step, and built-in rules are then incorporated to describe the variations caused by the interactions of the RPD components. Finally, the software draws each component using a series of curve functions. To validate the performance of the software, 112 RPD clinical design plans are randomly selected as inputs for the software, and the outputs are independently verified by experienced clinicians. The proposed methods are proven to be efficient and accurate and thus can be used to improve clinical quality.

Tumorigenesis, tumor growth, and prognosis are highly related to gene alterations and post-translational modifications (PTMs). Ubiquitination is a critical PTM that governs practically all aspects of cellular function. An increasing number of studies show that E3 ubiquitin ligases (E3s) are important enzymes in the process of ubiquitination that primarily determine substrate specificity and thus need to be tightly controlled. Among E3s, neural precursor cell expressed developmentally downregulated 4-1 (NEDD4-1) has been shown to play a critical role in modulating the proliferation, migration, and invasion of cancer cells and the sensitivity of cancer cells to anticancer therapies via regulating multiple substrates. This review discusses some significant discoveries on NEDD4-1 substrates and the signaling pathways in which NEDD4-1 participates. In addition, we introduce the latest potential therapeutic strategies that inhibit or activate NEDD4-1 activity using small molecules. NEDD4-1 likely acts as a novel drug target or diagnostic marker in the battle against cancer.

Clinical success of the proteasome inhibitor established bortezomib as one of the most effective drugs in treatment of multiple myeloma (MM). While survival benefit of bortezomib generated new treatment strategies, the primary and secondary resistance of MM cells to bortezomib remains a clinical concern. This study aimed to highlight the role of p53-induced RING-H2 (Pirh2) in the acquisition of bortezomib resistance in MM and to clarify the function and mechanism of action of Pirh2 in MM cell growth and resistance, thereby providing the basis for new therapeutic targets for MM. The proteasome inhibitor bortezomib has been established as one of the most effective drugs for treating MM. We demonstrated that bortezomib resistance in MM cells resulted from a reduction in Pirh2 protein levels. Pirh2 overexpression overcame bortezomib resistance and restored the sensitivity of myeloma cells to bortezomib, while a reduction in Pirh2 levels was correlated with bortezomib resistance. The levels of nuclear factor-kappaB (NF-κB) p65, pp65, pIKBa, and IKKa were higher in bortezomib-resistant cells than those in parental cells. Pirh2 overexpression reduced the levels of pIKBa and IKKa, while the knockdown of Pirh2 via short hairpin RNAs increased the expression of NF-κB p65, pIKBa, and IKKa. Therefore, Pirh2 suppressed the canonical NF-κB signaling pathway by inhibiting the phosphorylation and subsequent degradation of IKBa to overcome acquired bortezomib resistance in MM cells.

Background: RNA N 6-methyladenosine (m 6A) plays a critical role in regulating gene expression and determining cell fate. The dysregulation of m 6A modulators, including α-ketoglutarate-dependent dioxygenase AlkB homolog 5 (ALKBH5), has been reported to promote tumor development through their enzymatic function. However, the functions of mRNA m 6A and its modulators in multiple myeloma (MM) are largely unknown. Methods: We queried publicly available MM datasets to study the expression profile of m 6A modulators (METTL3, METTL14, WTAP, FTO, and ALKBH5) in MM and their relationships with clinical outcomes in patients with MM. Both gain- and loss-of-function studies were performed to investigate the role of ALKBH5 in MM. The cell proliferation assay, colony formation assay, Annexin V apoptosis analysis, and 5-ethynyl-2′-deoxyuridine (EdU) assay were performed to evaluate the functions of ALKBH5 in MM in vitro. Human MM cell line xenograft models were constructed to examine the effects of ALKBH5 knockdown or overexpression on MM growth in vivo. The rescue assay using catalytically inactive mutant ALKBH5-H204A was conducted to determine whether demethylation activity was required for the function of ALKBH5 in MM. Then, we performed RNA sequencing and m 6A sequencing to explore the key targets that mediated ALKBH5 function in MM. We investigated the gene regulatory mechanism of ALKBH5 in MM by m 6A immunoprecipitation assay, RNA immunoprecipitation assay, RNA decay assay, dual-luciferase reporter assay, and so forth. Gene set enrichment analysis and Western blotting were employed to determine the downstream signaling pathways regulated by ALKBH5 and the recognized target. Results: ALKBH5 was overexpressed in MM and associated with a poor prognosis in patients with MM. The increased ALKBH5 expression was required for the survival and growth of MM cells in vitro and in vivo. Mechanistically, m 6A demethylation activity was required for ALKBH5 to exert tumorigenic effects in MM. Tumor necrosis factor (TNF) receptor-associated factor 1 (TRAF1) was identified as a functionally important target of ALKBH5. ALKBH5 regulated TRAF1 expression via affecting mRNA stability of TRAF1 in an m 6A- and YTHDF2-dependent manner. ALKBH5 promoted MM cell growth and survival partly through TRAF1-mediated activation of NF-κB and MAPK signaling pathways. Conclusion: Our findings showed that ALKBH5 played an oncogenic role in MM and highlighted that ALKBH5 could potentially be a novel therapeutic target in MM. Disclosures No relevant conflicts of interest to declare.

Background Research has demonstrated that histone deacetylase (HDAC) is overexpressed in plasma cells. Panobinostat was the first HDAC inhibitor (HDACi) approved by FDA for the treatment of patients with relapse and refractory multiple myeloma (RRMM) in 2015. Chidamide is an oral subtype-selective HDACi, which was independently developed in China and approved as peripheral T-cell lymphoma. Preclinical findings have demonstrated the anti-myeloma activities of chidamide in vitro and in vivo. Currently, patients are recommended to take bortezomib and/or lenalidomide in first line treatment and might become less sensitive or resistant when disease progressed. Choices are limited for these patients as not all the new agents (i.e., second generation of PIs/ IMiDs, monoclonal antibody, et al.) were covered by insurance in China, which calls for more efficient and economical options. Here we report the initial efficacy and safety of this prospective, phase IIa, multicenter clinical trial with the chidamide based oral quadruplet regimen in patients with RRMM (ChiCTR2000035100). Methods The TC2D regimen (thalidomide 100mg on days 1-28, chidamide 5mg on days 1-24, cyclophosphamide 50mg on days 1-24 and dexamethasone 20mg on days 1,8,15 and 22) was administered to patients with RRMM of a 28-day cycle. In this trial, evaluation of overall response rate (ORR) was based on patients whose response ≥MR and clinical beneficial rate (CBR) was calculated in patients completed at least 3 cycles of TC2D regimen and reached ≥SD in this trial. Results A total of 32 patients were enrolled as of June 30, 2021, with a median age of 63.5 years (range 49-74). iFISH detected high-risk cytogenetics (defined by the presence of del (17p) or p53 mutation, t (4:14), t (14:16), t (14:20), amp (1q)) in 23 patients, and 82% (19/23) of which had unfavorable cytogenetics. All patients were exposed to at least one kind of PIs and/or IMiDs and 75% were double refractory to bortezomib and lenalidomide. 18 patients received 1-3 prior lines and 43% (14/32) were heavily pre-treated (>3 lines). The median number of cycles completed was 3 (range 1-15) and 59% (19/32) patients completed ≥ 3cycles at the cut-off date (Table 1). With the median follow-up of 6 months (range 0.7-19.5), the median progression free survival (PFS) was 3.3 months and the 6-mon PFS rate was 27.5% (Fig1a). Median overall survival (OS) has not reached yet, 6-mon survival rate was 82%, and the estimated 12-month survival rate was 65% (Fig 1b). Study end points were death (8 cases, 25%) and disease progression (24 cases, 75%). Patients who received ≥3 cycles of treatment had a superior median PFS (3.8 vs 1.4 months, P=0.01) than < 3 cycles. Of the 28 patients whose follow-up time more than 3 months, ORR was 25% and CBR was 46.4%, respectively. Better CBR (56.3% vs. 33.3%) and ORR (31.3% vs. 16.7%) were observed in patients who received less than 3 prior lines of therapy, although with no significant statistical difference. Stratified analysis of PFS showed no significant differences in sex, age, clinical classification, cytogenetic risk, prognosis score (DS and ISS staging system), and the status of ASCT. Stratified analysis of OS showed similar results to those associated with PFS. Grade 3/4 adverse events were mainly hematological toxicity (neutropenia 28%, anemia 34%, thrombocytopenia 15.6%), which could be tolerated. Fatigue was reported in 68.8% (22/32) of the patients. The incidence of all-cause infection was 37.5% (12/32). There were no treatment related deaths observed. Conclusions To our knowledge, this is the first report of chidamide-based oral quadruplet regimen for patients with RRMM. The preliminary results suggested excellent efficacy and relatively high safety, and different groups of patients could benefit from treatment with this regimen. A longer treatment period may strengthen this effect. The most common adverse events were hematological toxicity which could be controlled. As we known, choices of treatment are also influenced by physical and emotional impact of hospitalization or frequent hospital visits, which reflects the patient's ability to continue their treatment and quality of life. Hospitalization and intravenous fluids are not involved in this oral quadruplet treatment, which bring far more convenience and could be a cost-effective alternative for patients with RRMM. Updated results will be presented at the following trial. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Multiple myeloma (MM) is a malignant plasma disease closely associated with inflammation. In MM bone marrow microenvironment, bone marrow stromal cells (BMSCs) are the primary source of interleukin-6 (IL-6) secretion, which promotes the proliferation and progression of MM cells. However, it is still unknown how the microenvironment stimulates BMSCs to secrete IL-6. Interleukin-32 (IL-32) is a newly identified pro-inflammatory factor. It was reported that in solid tumors, IL-32 induces changes in other inflammatory factors including IL-6, IL-10, and TNF-α. The aim of this study was to investigate the expression of IL-32 and the role of IL-32 in the MM bone marrow microenvironment. Our data illustrate that MM patients have higher expression of IL-32 than healthy individuals in both bone marrow and peripheral blood. We used ELISA and qRT-PCR to find that malignant plasma cells are the primary source of IL-32 production in MM bone marrow. ELISA and Western blot analysis revealed that recombinant IL-32α induces production of IL-6 in BMSCs by activating NF-κB and STAT3 signaling pathways, konckdown of IL-32 receptor PR3 inhibit this process. Knockdown of IL-32 by shRNA decreased the proliferation in MM cells that induced by BMSCs. In conclusion, IL-32 secreted from MM cells has paracrine effect to induce production of IL-6 in BMSCs, thus feedback to promote MM cells growth.

We previously showed that the chemokine CCL2 can recruit macrophages (Mφs) to the bone marrow (BM) in multiple myeloma (MM) and that myeloma-associated Mφs are important in drug resistance. Here, we explore the role of increased CCL2 expression in the BM microenvironment of MM and elucidate the underlying mechanism. Our results show that CCL2 expression is associated with the treatment status of MM patients. Mφs interact with MM cells and further upregulate their expression of CCL2. These increased level of CCL2 polarizes Mφs toward the M2-like phenotype and promotes Mφs to protect MM cells from drug-induced apoptosis. Mechanistically, CCL2 upregulated the expression of the immunosuppressive molecular MCP-1-induced protein (MCPIP1) in Mφs. MCPIP1 mediates Mφs’ polarization and protection via dual catalytic activities. Additionally, we found that CCL2 induces MCPIP1 expression via the JAK2-STAT3 signaling pathway. Taken together, our results indicate that increased CCL2 expression in MM patients’ BM polarizes Mφs toward the M2-like phenotype and promotes the protective effect of Mφs through MCPIP1, providing novel insight into the mechanism of Mφs-mediated drug resistance in MM.

// Donghua He 1, * , Xing Guo 1, * , Enfan Zhang 1 , Fuming Zi 2 , Jing Chen 1 , Qingxiao Chen 1 , Xuanru Lin 1 , Li Yang 1 , Yi Li 1 , Wenjun Wu 1 , Yang Yang 1 , Jingsong He 1 , Zhen Cai 1 1 Bone Marrow Transplantation Center, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China 2 Department of Hematology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China * These authors contributed equally to this work Correspondence to: Zhen Cai, email: caiz@zju.edu.cn Keywords: apoptosis, dexamethasone, multiple myeloma, quercetin Received: February 23, 2016 Accepted: May 28, 2016 Published: June 14, 2016 ABSTRACT Quercetin, a kind of dietary flavonoid, has shown its anticancer activity in many kinds of cancers including hematological malignancies (acute myelogenous leukemia, chronic myelogenous leukemia, chronic lymphocytic leukemia, and MM) in vitro and in vivo . However, its effects on MM need further investigation. In this study, MM cell lines were treated with quercetin alone or in combination with dexamethasone. In order to observe the effects in vivo , a xenograft model of human myeloma was established. Quercetin inhibited proliferation of MM cells (RPMI8226, ARP-1, and MM.1R) by inducing cell cycle arrest in the G2/M phase and apoptosis. Western blot showed that quercetin downregulated c-myc expression and upregulated p21 expression. Quercetin also activated caspase-3, caspase-9, and poly(ADP-ribose)polymerase 1. Caspase inhibitors partially blocked apoptosis induced by quercetin. Furthermore, quercetin combined with dexamethasone significantly increased MM cell apoptosis. In vivo xenograft models, quercetin obviously inhibited tumor growth. Caspase-3 was activated to a greater extent when quercetin was combined with dexamethasone. In conclusion, quercetin alone or in combination with dexamethasone may be an effective therapy for MM.

Interleukin-32 (IL-32), a novel proinflammatory cytokine, is highly expressed in various cancer tissues and in established cancer cell lines. IL-32 has been revealed to serve a crucial role in human cancer development, including tumour initiation, proliferation and maintenance. The expression of IL-32 is regulated by numerous factors, including genetic variations, hypoxia and acidosis in the tumour microenvironment. Understanding the underlying mechanisms of IL-32 expression and its function are critical for the discovery of novel therapeutic strategies that target IL-32. This is a review of the current literature on the regulation and function of IL-32 in cancer progression, focusing on the molecular pathways linking IL-32 and tumour development.

Background With the development of novel therapeutic agents, the survival of multiple myeloma (MM) patients has much improved. However, the disease is incurable due to drug resistance. Previous studies have found that high-mobility group box 1 (HMGB1) is involved in inflammation, angiogenesis, DNA damage repair, and cancer invasion, progression, metastasis and drug resistance and that high HMGB1 expression is associated with poor MM prognosis, yet the role and mechanism of HMGB1 in MM remains unclear. Methods Through gene expression and Oncomine database analyses, we found that HMGB1 is associated with a poor prognosis in MM patients. RNA interference together with gene array analysis, cell proliferation and apoptosis assays, autophagy detection assays, western blotting, and in vivo xenograft models were employed to evaluate the effect of HMGB1 and the mechanism involved in MM drug resistance. Results MM cell lines and primary MM samples were found to express high levels of HMGB1, which was negatively associated with the 3-year survival of MM patients. HMGB1 knockdown in MM cells enhanced the inhibitory effect of chemotherapy with dexamethasone (Dex) via apoptosis induction. Furthermore, downregulation of HMGB1 activated the mTOR pathway, inhibited autophagy and increased DNA damage induced by Dex by modulating expression of related genes. In vivo, xenograft models showed that after Dex treatment, the tumor burden of HMGB1-knockdown mice was decreased compared with that of control mice. Conclusions Our research shows that HMGB1 participates in autophagy and DNA damage repair and that downregulation of HMGB1 enhances the sensitivity of MM cells to Dex, suggesting that HMGB1 may serve as a target for MM treatment.

The fine structure of the ommatidia in males of the short-faced scorpionfly Pan- orpodes kuandianensis was investigated using scanning and transmission electron microscopy. The result shows that the compound eyes of male P. kuandianensis are of the apposition type, consisting of over 1700 ommatidia. Each ommatidium is composed of a laminated cornea, a eucone crystalline cone, eight retinula cells, a pair of primary pigment cells, and a group of 16 secondary pigment cells. Along the optical axis of the ommatidium, seven elongated retinula cells contribute their rhabdomeres to a centrally fused rhabdom, which is in tight contact with the proximal end of the crystalline cone, but smaller than the cone end in diameter. The eighth retinula cell is located above the basal lamina and only contributes its rhabdomere to the proxi- mal part of the rhabdom. The microvilli of the rhabdom show an orthogonally-arranged orienta- tion. The ommatidia of Panorpodidae are more similar to those of Panorpidae than Bittacidae in structure, adding weight to the view that the sister group of Panorpodidae is Panorpidae rather than Bittacidae. Microsc. Res. Tech. 76:862-869, 2013. V C 2013 Wiley Periodicals, Inc.

We present the initial work toward developing a clinical decision support model for specific design of removable partial dentures (RPDs) in dentistry. We developed an ontological paradigm to represent knowledge of a patient’s oral conditions and denture component parts. During the case-based reasoning process, a cosine similarity algorithm was applied to calculate similarity values between input patients and standard ontology cases. A group of designs from the most similar cases were output as the final results. To evaluate this model, the output designs of RPDs for 104 randomly selected patients were compared with those selected by professionals. An area under the curve of the receiver operating characteristic (AUC-ROC) was created by plotting true-positive rates against the false-positive rate at various threshold settings. The precision at position 5 of the retrieved cases was 0.67 and at the top of the curve it was 0.96, both of which are very high. The mean average of precision (MAP) was 0.61 and the normalized discounted cumulative gain (NDCG) was 0.74 both of which confirmed the efficient performance of our model. All the metrics demonstrated the efficiency of our model. This methodology merits further research development to match clinical applications for designing RPDs. This paper is organized as follows. After the introduction and description of the basis for the paper, the evaluation and results are presented in Section 2. Section 3 provides a discussion of the methodology and results. Section 4 describes the details of the ontology, similarity algorithm, and application.

The evolutionary origin of holometabolous larvae is a long-standing and controversial issue. The Mecoptera are unique in Holometabola for their larvae possessing a pair of compound eyes instead of stemmata. The ultrastructure of the larval eyes of the scorpionfly Panorpa dubia Chou and Wang, 1981 was investigated using transmission electron microscopy. Each ommati- dium possesses a cornea, a tetrapartite eucone crystalline cone, eight retinula cells, two primary pigment cells, and an undetermined number of secondary pigment cells. The rhabdomeres of the eight retinula cells form a centrally- fused, tiered rhabdom of four distal and four proximal ret- inula cells. The rhabdomeres of the four distal retinula cells extend distally into a funnel shape around the basal surface of the crystalline cone. Based on the similarity of the larval eyes of Panorpidae to the eyes of the hemime- tabolous insects and the difference from the stemmata of the holometabolous larvae, the evolutionary origin of the holometabolous larvae is briefly discussed. J. Morphol.

We aimed to characterize the role of B-cell activating factor (BAFF) in macrophage-mediated resistance of multiple myeloma (MM) cells to bortezomib (bort), and to further understand the molecular mechanisms involved in the process. First, we detected BAFF and its three receptors on myeloma cells and macrophages using the quantitative reverse transcriptase-polymerase chain reaction and flow cytometry. The secretion of BAFF was tested in patients with MM, MM cell lines, and macrophages. The ability of macrophages to protect MM cells from bort-induced apoptosis was significantly attenuated using BAFF-neutralizing antibody in the co-culture system or knocking down the expression of BAFF in macrophages with small interfering RNA. We also showed that the MM–macrophage interaction through BAFF and its receptors was primarily mediated by the activation of Src, Erk1/2, Akt, and nuclear factor kappa B signaling and the suppression of caspase activation induced by bort. Our data demonstrated that BAFF played a functional role in the macrophage-mediated resistance of MM cells to bort, suggesting that targeting BAFF may provide a basis for the molecular- and immune-targeted therapeutic approach.

Background: Multiple myeloma (MM) is among the most common hematologic malignancies. Proteasome inhibitor bortezomib (Bor) is one of the most effective drugs for treatment of MM. However, during long-term Bor treatment, MM cells may eventually develop acquired-resistance to Bor which results in recurrence and a poor prognosis of MM. Several researches show that E3 ubiquitin ligases (E3s) primarily determine the substrate specificity of ubiquitin proteasome system and play an essential role in Bor resistance of MM. NEDD4-1 E3s, a founding member of the Neural precursor cell-Expressed Developmentally Downregulated gene 4 (NEDD4) family, was proved to involve in the proliferation, migration, invasion of cancer cells and the sensitivity of anticancer therapies. Our current study aims to explore the role and underlying mechanism of NEDD4-1 in acquired resistance of Bor in MM. Methods: The mRNA and protein levels of NEDD4-1 and its substrates in MM cell lines (H929, LP-1, RPMI8226, OPM-2 and ARP-1) and MM patients were detected by Quantitative Realtime PCR and Western Blotting. Lentiviral plasmids containing shRNA against NEDD4-1 were transfected into MM cells. Cell viability, proliferation and apoptosis of MM cells were measured by Cell Counting kit8 (CCK8) and flow cytometry. Gene array was used to compare the gene expression profiles of a panel of Bor treated MM cells vs vehicle-treated MM cells. Results: Gene array showed NEDD4-1 was significantly increased in MM cells treated with Bor. MM cells (CD138+ plasma cells of the bone marrow) from refractory/recurrence patients expressed lower NEDD4-1 than primary patient myeloma cells. Also, MM cell lines H929, ARP-1, LP-1 highly expressed NEDD4-1 at mRNA and protein levels. RPMI8226 and OPM-2 were relatively low expressed. Cell growth assay displayed no significant difference in proliferation between the NEDD4-1 knockdown (KD) and the control group (P>0.05). After suppression of NEDD4-1 using shRNAs, the killing effect of Bor in MM was significantly weaker than the control group (P Conclusion: Collectively, our study reveals that inhibition of NEDD4-1 can reduce MM sensitivity to Bor via regulating PTEN, c-Myc and Bcl-2, may be related to JAK/STAT signaling pathway, which suggests that NEDD4-1 probably acts as a novel drug target and therapeutic paradigm in the battle against multiple myeloma. Disclosures No relevant conflicts of interest to declare.

Background:B-cell-activating factor (BAFF) is a member of the TNF family that critical for maintenance of B-cell development and homeostasis. BAFF receptor (BAFF-R), B-cell maturation antigen (BCMA) and transmembrane activator and CAML interactor (TACI) are three BAFF receptors. It has been reported that BAFF is expressed by neutrophils, monocytes, dentritic cells and macrophages and modulates the proliferation, survival and drug resistance of multiple myeloma (MM) cells. Our previous study showed that, macrophages protect MM cells from drug-induced apoptosis by direct interaction with MM cells. We hypothesized that BAFF/BAFF receptors play a role in macrophage-induced bortezomib resistance in myeloma. Methods: First, the expression levels of BAFF and its three receptors in primary MM cells, MM cell lines and peripheral blood monocyte(PBMC)-induced macrophages were detected by semiquantitative real time-polymerase chain reaction (qPCR),Western blot and flow-cytometry. Also the concentration of BAFF in the supernatants of MM patients' bone marrow, MM cell lines and macrophages were determined by ELISA. Second, Primary MM cells and MM cell lines were cocultured with macrophages for the indicated time (usually 4-6h and 24h), for some experiments, we added bortezomib to the coculture system. Cell viability and apoptosis of MM cells were verified by Cell Counting Kit-8(CCK8) after treated with recombinant human (rh) BAFF, BAFF neutralizing antibody and BAFF siRNA. The interactions between BAFF and its receptors are unveiled by flow-cytometry. Then, cell survival signaling activations that may confer MM drug resistance were examined by Western blot. Results: Two receptors of BAFF, TACI and BCMA were highly expressed in various MM cell lines. The expressions of BAFF in PBMC-induced macrophages were heterogeneous. Functional studies showed that rhBAFF promoted RPMI8226 and ARP1 myeloma cells growth (P Conclusions: Our data show that macrophage might induce drug resistance of MM cells by the interaction of BAFF and BAFF receptors, leading to a reduction in caspase proteins and subsequent activation of Src and Erk1/2 kinases and NF-κB2 pathways .These studies reveal a promising unknown role for BAFF/BAFF receptors, suggesting that targeting macrophage-MM interactions may represent a promising therapeutic modality. Disclosures No relevant conflicts of interest to declare.

Background: Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults which is still incurable although novel drugs and new combination of chemotherapies are used . With the development of genetic and molecular biology technologies, more and more genes are found to be related to leukemogenesis and drug resistance of AML. TET2, a member of the ten-eleven-translocation gene family which can modify DNA by catalyzing the conversion of 5-mehtyl-cytosine to 5-hydroxymethyl-cytosine , is often inactivated through mutation or deletion in myeloid malignancies. Recent research reported that TET2 knock-down can promote proliferation of hematopoietic stem cells and leukemic cells. Also, several clinical studies showed that patients with TET2 mutation or low levels of TET2 expression have more aggressive disease courses than those with normal levels of TET2. However, the mechanism of the phenomenon is unknown. Our aim is to uncover how TET2 protein level is negatively correlated with AML cell proliferation and to provide a better view of target therapy in AML. Methods: We determined the expression levels of TET2 and other target genes in acute leukemia cell lines, bone marrow AML specimens, and peripheral blood mononuclear cells from healthy donors by qRT-PCR and Western blot. We also determined the mutation status of TET2 in AML cell lines. CCK8 and flow cytometry were used to determine cell proliferation, cell apoptosis, and cell cycle profile. Methylation-specific PCR were used to examine the methylation status in gene promoter regions. Also, we developed TET2 knock-down lentivirus to transfect AML cell lines to examine the effect of TET2 depletion. Last, RNA-seq was used to compare gene expression level changes between TET2 knock-down cell lines and the control cell lines. Results: AML cells from AML cell lines (KG-1,U937, Kasumi, HL-60, THP-1, and MV4-11) and AML patients' specimens expressed lower levels of TET2 than those of PBMC from the healthy donor (P Conclusion: Our study showed that knocking down TET2 promoted leukemic cell proliferation. This phenomenon may correlate to Pim-1 up-regulation. Our clinical data also showed that the expression of TET2 and Pim-1 have an inverse relationship. The mechanism of TET2 regulating Pim-1 expression may be related to the epigenetic modulation function of TET2. Finally, we found TET2 downregulation could increase leukemia vulnerability to Pim-1 inhibitor and decitbine, and provide a novel view of target therapy in AML. Disclosures No relevant conflicts of interest to declare.

Background: Multiple myeloma (MM) is the second mostly diagnosed disease among hematological malignancies after lymphoma. With the novel agents, the survival of MM patients has been improved significantly but still remains incurable because of drug resistance. Studies have found that high-mobility group box 1 protein (HMGB1) was involved in inflammation, angiogenesis, and cancer invasion progression, metastasis, and drug resistance. Our research was aimed at exploring the role of HMGB1 in MM cell proliferation and drug resistance. Methods: First, semi-quantitative real time-polymerase chain (qRT-PCR) and western blot was used to determine the levels of HMGB1 mRNA and protein expression in MM cell lines (RPMI8226, CAG, and MM.1S) and primary MM samples. Second, MM cells were transfected with HMGB1-knockdown lentivirus and the Cell Counting Kit 8 (CCK8) assay was used to determine the proliferation of MM cells with or without chemotherapeutic drugs dexamethasone (Dex) and doxorubicin (ADM). Then cell apoptosis was detected by flow cytometry. Third, Affymetrix HTA 2.0 Array was used to compare changes in gene expression levels between HMGB1-knockdown cells and the control cells and qRT-PCR was used to verify the array results. Last, Western bolt was performed to analyze changes in signaling pathways after HMGB1 knockdown. Results: MM cell lines and primary MM samples expressed high levels of HMGB1 mRNA and protein. Although there was no difference in MM cell proliferation between HMGB1-knockdown group and the control group (P>0.05), HMGB1-knockdown significantly enhanced inhibitory effect of chemotherapy with Dex and ADM in comparison with the wildtype HMGB1 control (P Conclusions: Our research showed that downregulation of HMGB1 increased sensitivity of MM cells to Dex and ADM through increasing apoptosis and regulating mTOR, NF-κB, PI3K-AKt, and p38-MAPK pathways. Disclosures No relevant conflicts of interest to declare.

Background: Multiple myeloma (MM) is closely associated with inflammation. Patients with auto-immune disease、history of infection and other inflammatory disease have higher incidence of MM. IL-6 is the most important inflammatory factor in MM which plays a key role in the proliferation and progression. We previously demonstrated that MM cells were modified by bone marrow stromal cells (BMSCs) that formulate a inflammatory microenvironment in bone marrow (BM) and secret IL-6. How the inflammation makes BMSCs secret IL-6, however, remained undocumented. Our subsequent study compared the differential secretion of peripheral blood (PB) between MM patients and normal people by cytokine array, and showed that interleukin 32(IL-32) is highly expressed in MM patients. IL-32, also named natural killer 4(NK-4), is a newly found inflammatory factor. It was reported in solid tumors IL-32 is a pro-inflammatory factor which triggers a massive amplification of inflammatory process resulting in the change of other inflammatory factor including IL-6,IL-10,TNF-α. In this study, we examined BMSCs cytokines in MM BM and found that IL-32 was a functional factor in the process of inflammation in MM BM microenvironment. Results: First, to test our previous study, we detected IL-32 in BM supernatant and PB supernatant in both MM patients (n=45) and healthy controls (n=13) by ELISA. Result showed that in both BM and PB, MM patients have higher expression of IL-32 compared to healthy controls (P Second, we stimulated the MM BMSCs with recombinant IL-32α, and found that the secretion of IL-6,CCL3 (MIP1-α), CCL4(MIP-1β) were significantly increased and CCL-5(RANTES)and IL-10 were decreased (P Finally, our group co-cultured the MM BMSCs with 8226 and OPM-2 cells. The secretion of IL-6 and the phosphorylation of JAK-STAT pathway in BMSCs were also increased. Knockdown of IL-32 in 8226 and OPM-2 cells weakened these changes.MM Cell proliferation and cell cycles after co-culture with MM BMSCs are under investigation. Conclusion: our findings suggest that IL-32 is mainly secreted by MM cells. It may not directly promote the MM cells to grow. However, IL-32 promote the MM BMSCs to secret more cytokines including IL-6,CCL3,CCL4 by activating the JAK-STAT3 pathway, which lead to a amplification of inflammation in BM environment, resulting in the cell proliferation . Disclosures No relevant conflicts of interest to declare.

Dorsal ocelli are important visual organs of insects to perform a variety of behavioral functions. However, the fine structure of ocelli has not been studied in many groups of insects. In this paper the ocellar ultrastructure of the short-faced scorpionfly Panorpodes kuandianensis was investigated using light microscopy and scanning and transmission electron microscopy. The adult of P. kuandianensis possesses one median and two lateral ocelli. Each ocellus comprises a cornea, a layer of corneagenous cells, a clear zone, a retina, and pigment cells. The cornea assumes a domed shape. Under the layer of corneagenous cells is a clear zone, which differs greatly between the median and lateral ocelli, implying they may be divergent in function. The retina comprises elongated retinula cells, which are divided into three regions: a distal rhabdomal region, a middle cytoplasmic region, and a proximal axonal region. In the distal rhabdomal region, most of the rhabdoms are formed by rhabdomeres of two adjacent retinula cells; some are formed by three or four retinula cells. The middle cytoplasmic region comprises the retinula cell segments with nuclei but free of rhabdom. Pigment granules are present among the retinula cells. In the proximal axonal region all retinula cells transform to axons, which synapse with the dendrites of second-order neurons at the base of the ocelli. The relationships among Panorpodidae, Panorpidae and Bittacidae are discussed based on ocellar structure.

The fine structure of the ommatidia in males of the short-faced scorpionfly Panorpodes kuandianensis was investigated using scanning and transmission electron microscopy. The result shows that the compound eyes of male P. kuandianensis are of the apposition type, consisting of over 1700 ommatidia. Each ommatidium is composed of a laminated cornea, a eucone crystalline cone, eight retinula cells, a pair of primary pigment cells, and a group of 16 secondary pigment cells. Along the optical axis of the ommatidium, seven elongated retinula cells contribute their rhabdomeres to a centrally fused rhabdom, which is in tight contact with the proximal end of the crystalline cone, but smaller than the cone end in diameter. The eighth retinula cell is located above the basal lamina and only contributes its rhabdomere to the proximal part of the rhabdom. The microvilli of the rhabdom show an orthogonally-arranged orientation. The ommatidia of Panorpodidae are more similar to those of Panorpidae than Bittacidae in structure, adding weight to the view that the sister group of Panorpodidae is Panorpidae rather than Bittacidae.

Background: Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults and have very lethal rate. Chemotherapy is the main method to treat AML, but the complete remission rate is still not very optimal. With the development of genetic and molecular biology technologies, more and more molecular biomarkers are found, some of them are useful for us to evaluate the prognosis and can help us to tailor the treatment plan for different patients. TET2, a member of the ten-eleven-translocation(TET) family genes which can modify DNA by catalyzing the conversion of 5mehtyl-cytosine(5-mC) to 5-hydroxymethyl-cytosine(5-hmC), is often inactivated through loss-of-function mutation and deletion in myeloid malignancies. Recent clinical research reported that the lower the expression of TET2 in MDS and AML patients, the better the response to decitabine (DAC, a demethylation agent) will be. However, the mechanism of the phenomenon is still unknown. Our investigation is trying to uncover the mechanism how TET2 protein levels are negatively related with AML sensitivity to decitabine. Methods: We detected TET2 mRNA expression level in acute leukemia cell lines, bone marrow AML specimens and peripheral blood mononuclear cells from healthy donors by semiquantitative real time polymerase chain reaction (qRT-PCR). Western blot is also applied to detect TET2 protein expression. In order to access TET2 methylation status, we used the methylation-specific PCR. And we also checked the mutant status of TET2 in U937 and KG-1 cell line. CCK8 and flow cytometry are used to detect cell proliferation rate, cell apoptosis, and cell cycle profile. Also, we developed TET2 knock-down and overexpression lentivirus to transfect AML cell lines to explore the mechanism why TET2 expression level is related to the response of DAC. Last, gene array is used to compare gene expression level changes between TET2 knock-down cell lines (or TET2 overexpression cell lines) and the control cell lines. Results: The AML cell lines (KG-1, U937, Kasumi, HL-60, THP-1) and AML patients specimens express lower TET2 than that of PBMC from the healthy donor (P Conclusion: Our study showed that the sensitivity to decitabine of AML cell lines is related to TET2 expression level, knock-down TET2 in KG-1 can increase its vulnerability to decitbine. And the mechanism may be related to the changing expression levels of the genes which regulating cell cycles and DNA replication. Disclosures No relevant conflicts of interest to declare.

Background: Multiple myeloma (MM) is a hematological malignancy with clonal plasma cell hyperplasia, which is still an incrurable disease since chemoresistance remains the major problem in MM management. Quercetin, a kind of dietary flavonoids, has shown its anticancer activity in many kinds of cancer cell lines and we tried to explore the effect of quercetin in MM. Methods: In vitro, we examined the proliferation of MM cell lines(RPMI8226,ARP-1,MM1R) after treatment with quercetin combined with or without dexamethasone by MTT.Flow cytometry was used to detect apoptosis and cell cycle of MM cells induced by quercetin with or without dexamethasone.Then we detected mRNA and protein expression associated with apoptosis and cell cycle arrest by semiquantitative real time-polymerase chain (qRT-PCR)and western blot analysis. In vivo,a xenograft mice model of human myeloma was established and the mice received vehicle or quercetin alone or dexamethasone alone or quercetin combinded with dexamethasone, and the tumorburdern and the tumor tissue samples were analyzed by tumor volume and immunohistochemistry. Results: Quercetin inhibited proliferation of MM cells by inducing apoptosis and cell cycle arrest in the G0/G1 or G2 phase(quercetin group vs control,p Conclusions: Quercetin inhibits proliferation of MM cells by inducing apoptosis and cell cycle arrest in the G0/G1 or G2 phase through downregulating c-myc and cyclinD1 and upregulating p21 .Quercetinalso displays synergistic inhibition effect with dexamethasone.Thus,quercetin combination with dexamethasone therapy may be an effective option for MM patients. Disclosures No relevant conflicts of interest to declare.

The ultrastructure of the compound eyes of scorpionflies Sinopanorpa tincta (Navas, 1931), Panorpa liui Hua, 1997 and Panorpa sexspinosa Cheng, 1949 in Panorpidae were comparatively investigated using transmission electron microscopy. Their compound eyes share the following characters: each ommatidium possesses a corneal lens, a eucone tetrapartite crystalline cone surrounded by a pair of primary pigment cells, and eight retinula cells. Seven retinula cells (R1–R7) are in contact with the crystalline cone and extend to the basal lamina, but the eighth retinula cell (R8) is only restricted to the basal level of the ommatidium. The rhabdomeres of cells R1–R7 form a centrally fused rhabdom that almost spans the full length of the ommatidium, and that of R8 only contributes to the basal part of the rhabdom. The distal part of the rhabdom projects upward into the region between the cone cell tips and force the cone cells to split apart into four thin cone cell roots that run along a narrow intercellular gap between adjacent retinula cells. The number of secondary pigment cells varies from 12 in P. liui to 16 in P. sexspinosa and S. tincta. Based on the dissimilarity of the imaginal and larval ommatidial structure, the imaginal compound eyes are very unlikely to be directly developed from the larval compound eyes in the Panorpidae.

Background Proteasome inhibitor bortezomib is an effective approach to the treatment of multiple myeloma (MM), but drug resistance often emerges and limits its retreatment. However, the action mechanisms are not fully understood. Several lines of evidence link E3 ligase to myeloma and its drug resistance. Pirh2 (p53-induced RING-H2) E3 ubiquitin ligase with intrinsic ubiquitin-protein ligase activity for polyubiquitination and subsequently proteasomal degradation was predisposed for plasma cell hyperplasia and tumorigenesis as reported. In this study, we examined Pirh2 expression in plasma cells of the bone marrow (CD138+ cells) from MM patients and investigate the effect of Pirh2 on the viability, proliferation, survival and drug resistance of MM cells. Methods Bortezomib-sensitive malignant haematopoetic cells can acquire secondary resistance to Bortezomib in vitro. To identify some of the mechanisms involved, we developed myeloma cell lines OPM-2 and RPMI8226 bortezomib resistant (OPM-2-BR, RPMI8226-BR) derivative lines by continuous culture in sub-lethal concentrations of bortezomib. Clones of OPM-2-BR and RPMI8226-BR were obtained after several months, and acquired resistance to bortezomib remained stable over months with extended stimulus duration in the presence of bortezomib. Pirh2 mRNA and protein expressions were detected by real time quantitative PCR(Q-RT PCR) and Western blotting. We also generated stable Pirh2 knock down cell lines and stable Pirh2 overexpression cell lines. Results We found differential expression of Pirh2 in bortezomib-resistant (BR) cells, compared to wild type (WT) controls by Q-RT PCR and Western blotting. We confirmed generally Pirh2 mRNA and protein expressions in MM cell lines. Besides, Pirh2 mRNA expression was also determined from bone marrow samples of MM patients. In summary, we showed that Pirh2 is more highly expressed in MM cell lines and patient MM cells (from newly diagnosed or refractory/recurrence patients with MM) than in normal bone marrow mononuclear cells from normal donors (P Conclusions Collectively, Our findings demonstrate a novel role for Pirh2, which suggests that Pirh2 may act by an unknown mechanism involved in bortezomib resistance of MM. An improved understanding of it can lead to better therapeutics for bortezomib retreatment which will be a rational strategy for clinical translation. Disclosures No relevant conflicts of interest to declare.

Background ：Multiple myeloma (MM) is an malignant disease of clonal plasma cell hyperplasia, which incidence is increasing in recent years. Chemotherapy is the main method to treat MM, but because of drug resistance, MM is still an incrurable disease. High-mobility group box 1 protein (HMGB1) is a chromatin associated nuclear protein, which participated in DNA damage repair , rearrangement, and it also as an extracellular damage associated molecular pattern molecule(DAMP) involved in inflammation, neoplastic progression, angiogenesis, invasion and metastasiss and drug resistance of kinds of tumor cells. There’s no research about the role of HMGB1 in multiple myeloma before. Methods: First, We detected HMGB1 mRNA and protein expression level in MM cell lines and primary MM cells by semiquantitative real time-polymerase chain (qRT-PCR)and western blot respectively. The concentration of HMGB1 in the culture supernatants of MM cell lines and primary MM cells was detected by ELISA. Second, we constructed Lentivirus vector with HMGB1 shRNA, infected the lentivirus to MM cells to knockdown HMGB1 expression. Then Chemo-drugs (ADM, quercetin and bortezomib) were added to MM cells, flow cytometry was used for the detection of cell apoptosis. Results:MM cell line and primary MM cell all express HMGB1 with high level. The concentration of HMGB1 in the MM cell supernatants was significantly elevated after chemotherapy treatment compared with untreated cells(p Conclusions: Our study showed that the concentration of HMGB1 in the MM cell supernatants was significantly elevated after chemotherapy treatment. Further more, knockdown of HMGB1 by shRNA increased the sensitivity of MM cells to chemotherapy. Disclosures No relevant conflicts of interest to declare.