Dihydrocelastrol induces cell death and suppresses angiogenesis through BCR/AP-1/junb signalling in diffuse large B cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma. Although treatment options have improved, a large proportion of patients show low survival rates, highlighting an urgent need for novel therapeutic strategies. The aim of this study was to investigate the efficacy of the new small-molecule compound dihydrocelastrol (DHCE), acquired through the structural modification of celastrol (CE), in the treatment of DLBCL. DHCE showed potent anti-lymphoma efficacy and synergistic effects with doxorubicin. DHCE triggered DLBCL cell apoptosis and G0/G1-phase blockade, thereby hindering angiogenesis. DHCE inhibited B-cell receptor cascade signalling and Jun B and p65 nuclear translocation, thereby suppressing pro-tumourigenic signalling. Finally, DHCE exerted lower toxicity than CE, which showed severe hepatic, renal, and reproductive toxicity in vivo. Our findings support further investigation of the clinical efficacy of DHCE against DLBCL.

Design and synthesis of cantharidin derivative DCZ5418 as a TRIP13 inhibitor with anti-multiple myeloma activity in vitro and in vivo.

Natural product cantharidin can inhibit multiple myeloma cell growth in vitro, while serious adverse effects limited its clinical application. Therefore, the structural modification of cantharidin is needed. Herein, inspired by the structural similarity of the aliphatic endocyclic moiety in cantharidin and TRIP13 inhibitor DCZ0415, we designed and synthesized DCZ5418 and its nineteen derivatives. The molecular docking study indicated that DCZ5418 had a similar binding mode to TRIP13 protein as DCZ0415 while with a stronger docking score. Moreover, the bioassay studies of the MM-cells viability inhibition, TRIP13 protein binding affinity and enzyme inhibiting activity showed that DCZ5418 had good anti-MM activity in vitro and definite interaction with TRIP13 protein. The acute toxicity test of DCZ5418 showed less toxicity in vivo than cantharidin. Furthermore, DCZ5418 showed good anti-MM effects in vivo with a lower dose administration than DCZ0415 (15 mg/kg vs 25 mg/kg) on the tumor xenograft models. Thus, we obtained a new TRIP13 inhibitor DCZ5418 with improved safety and good activity in vivo, which provides a new example of lead optimization by using the structural fragments of natural products.

A novel pterostilbene compound DCZ0825 induces macrophage M1 differentiation and Th1 polarization to exert anti-myeloma and immunomodulatory.

Multiple myeloma (MM) is an incurable and recurrent malignancy characterized by abnormal plasma cell proliferation. There is an urgent need to develop effective drugs in MM. DCZ0825 is a small molecule compound derived from pterostilbene with direct anti-myeloma activity and indirect immune-killing effects though reversal of the immunosuppression. DCZ0825 inhibits the activity and proliferation of MM cells causing no significant toxicity to normal cells. Using flow cytometry, this study found that DCZ0825 induced caspase-dependent apoptosis in MM cells and arrested the cell cycle in the G2/M phase by down-regulating CyclinB1, CDK1 and CDC25. Moreover, DCZ0825 up-regulated IRF3 and IRF7 to increase IFN-γ, promoting M2 macrophages to transform into M1 macrophages, releasing the immunosuppression of CD4T cells and stimulated M1 macrophages and Th1 cells to secrete more INF-γ to form immune killing effect on MM cells. Treatment with DCZ0825 resulted in an increased proportion of positive regulatory cells such as CD4T, memory T cells, CD8T, and NK cells, with downregulation of the proportion of negative regulatory cells such as Treg cells and MDSCs. In conclusion, DCZ0825 is a novel compound with both antitumor and immunomodulatory activity.

Berberine derivative DCZ0358 induce oxidative damage by ROS-mediated JNK signaling in DLBCL cells.

The most common neoplasm among adult lymphomas is diffuse large B-cell lymphoma (DLBCL), typically characterized by pain-free and progressive lymph node enlargement. Due to high heterogeneity of DLBCL, 30-40 % of patients are resistant to R-CHOP standard chemoimmunotherapy. DCZ0358 is a new compound designed and synthesized from berberine by our group and the molecular mechanism by which it inhibited DLBCL growth has attracted our widespread attention. In this study, we employed the CCK8 assay to reveal that DCZ0358 inhibited proliferation in a dependent manner of time and dosage of DLBCL cells. Moreover, flowcytometry and western blot results showed that DCZ0358 downregulated the expression of CDK4, CDK6 and CyclinD1 to block cell cycle progression in G0/G1 phase. Furthermore, DCZ0358 enhanced mitochondrial membrane potential depolarization, promoted mitochondrial permeability transport pore openness, increased cytoplastic Ca2+ levels and decreased intracellular adenosine triphosphate production, which led to mitochondrial dysfunction. In particular, DCZ0358 treatment triggered cell apoptosis and elevated intracellular reactive oxygen species (ROS) levels, which subsequently mediated JNK pathway activation. Further research indicated the pre-treatment with ROS scavenger N-acetylcysteine (NAC) and JNK inhibitor SP600125 could partially attenuate apoptosis and DNA damage triggered by DCZ0358. Most importantly, DCZ0358 exhibited synergistic anti-tumor effects when combined with etoposide, a common clinical anti-DLBCL drug, both in vitro and certainly in vivo. Above results demonstrated anti-tumor molecular mechanism of DCZ0358 in DLBCL cells and highlighted the ROS/JNK/DNA damage pathway as a potential target in therapies, which have implications for the development of more effective clinical treatments for DLBCL.

TI17, a novel compound, exerts anti-MM activity by impairing Trip13 function of DSBs repair and enhancing DNA damage.

BACKGROUND: Thyroid hormone receptor interacting protein 13 (Trip13) is an AAA-ATPase that regulates the assembly or disassembly protein complexes and mediates Double-strand breaks (DSBs) repair. Overexpression of Trip13 has been detected in many cancers and is associated with myeloma progression, disease relapse and poor prognosis inmultiple myeloma (MM). METHODS: We have identified a small molecular, TI17, through a parallel compound-centric approach, which specifically targets Trip13. To identify whether TI17 targeted Trip13, pull-down and nuclear magnetic resonance spectroscopy (NMR) assays were performed. Cell counting kit-8, clone formation, apoptosis and cell cycle assays were applied to investigate the effects of TI17. We also utilized a mouse model to investigate the effects of TI17 in vivo. RESULTS: TI17 effectively inhibited the proliferation of MM cells, and induced the cycle arrest and apoptosis of MM cells. Furthermore, treatment with TI17 abrogates tumor growth and has no apparent side effects in mouse xenograft models. TI17 specifically impaired Trip13 function of DSBs repair and enhanced DNA damage responses in MM. Combining with melphalan or HDAC inhibitor panobinostat triggers synergistic anti-MM effect. CONCLUSIONS: Our study suggests that TI17 could be acted as a specific inhibitor of Trip13 and supports a preclinical proof of concept for therapeutic targeting of Trip13 in MM.

Dihydrocelastrol induces antitumor activity and enhances the sensitivity of bortezomib in resistant multiple myeloma by inhibiting STAT3-dependent PSMB5 regulation.

Multiple myeloma (MM) is characterized by excessive aggregation of B-cell-derived malignant plasma cells in the hematopoietic system of bone marrow. Previously, we synthesized an innovative molecule named dihydrocelastrol (DHCE) from celastrol, a triterpene purified from medicinal plant Tripterygium wilfordii. Herein, we explore the therapeutic properties and latent signal transduction mechanism of DHCE action in bortezomib (BTZ)-resistant (BTZ-R) MM cells. In this study, we first report that DHCE shows antitumor activities in vitro and in vivo and exerts stronger inhibitory effects than celastrol on BTZ-R cells. We find that DHCE inhibits BTZ-R cell viability by promoting apoptosis via extrinsic and intrinsic pathways and suppresses BTZ-R MM cell proliferation by inducing G0/G1 phase cell cycle arrest. In addition, inactivation of JAK2/STAT3 and PI3K/Akt pathways are involved in the DHCE-mediated antitumor effect. Simultaneously, DHCE acts synergistically with BTZ on BTZ-R cells. PSMB5, a molecular target of BTZ, is overexpressed in BTZ-R MM cells compared with BTZ-S MM cells and is demonstrated to be a target of STAT3. Moreover, DHCE downregulates PSMB5 overexpression in BTZ-R MM cells, which illustrates that DHCE overcomes BTZ resistance through increasing the sensitivity of BTZ in resistant MM via inhibiting STAT3-dependent PSMB5 regulation. Overall, our findings imply that DHCE may become a potential therapeutic option that warrants clinical evaluation for BTZ-R MM.

The novel norcantharidin derivative DCZ5417 suppresses multiple myeloma progression by targeting the TRIP13-MAPK-YWHAE signaling pathway.

BACKGROUND: Multiple myeloma (MM), an incurable disease owing to drug resistance, requires safe and effective therapies. Norcantharidin (NCTD), an active ingredient in traditional Chinese medicines, possesses activity against different cancers. However, its toxicity and narrow treatment window limit its clinical application. In this study, we synthesized a series of derivatives of NCTD to address this. Among these compounds, DCZ5417 demonstrated the greatest anti-MM effect and fewest side effects. Its anti-myeloma effects and  the mechanism were further tested. METHODS: Molecular docking, pull-down, surface plasmon resonance-binding, cellular thermal shift, and ATPase assays were used to study the targets of DCZ5417. Bioinformatic, genetic, and pharmacological approaches were used to elucidate the mechanisms associated with DCZ5417 activity. RESULTS: We confirmed a highly potent interaction between DCZ5417 and TRIP13. DCZ5417 inhibited the ATPase activity of TRIP13, and its anti-MM activity was found to depend on TRIP13. A mechanistic study verified that DCZ5417 suppressed cell proliferation by targeting TRIP13, disturbing the TRIP13/YWHAE complex and inhibiting the ERK/MAPK signaling axis. DCZ5417 also showed a combined lethal effect with traditional anti-MM drugs. Furthermore, the tumor growth-inhibitory effect of DCZ5417 was demonstrated using in vivo tumor xenograft models. CONCLUSIONS: DCZ5417 suppresses MM progression in vitro, in vivo, and in primary cells from drug-resistant patients, affecting cell proliferation by targeting TRIP13, destroying the TRIP13/YWHAE complex, and inhibiting ERK/MAPK signaling. These results imply a new and effective therapeutic strategy for MM treatment.

Ribosomal protein S3 mediates drug resistance of proteasome inhibitor: potential therapeutic application in multiple myeloma.

Multiple myeloma (MM) remains incurable due to drug resistance. Ribosomal protein S3 (RPS3) has been identified as a non-Rel subunit of NF-κB. However, the detailed biological roles of RPS3 remain unclear. Here, we report for the first time that RPS3 is necessary for MM survival and drug resistance. RPS3 was highly expressed in MM, and knockout of RPS3 in MM inhibited cell growth and induced cell apoptosis both in vitro and in vivo. Overexpression of RPS3 mediated the proteasome inhibitor resistance of MM and delayed the survival of MM tumour-bearing animals. Moreover, our present study found an interaction between RPS3 and the thyroid hormone receptor interactor 13 (TRIP13), an oncogene related to MM tumorigenesis and drug resistance. We demonstrated that the phosphorylation of RPS3 was mediated by TRIP13 via PKCδ, which played an important role in activating the canonical NF-κB signalling and inducing cell survival and drug resistance in MM. Notably, the inhibition of NF-κB signalling by the small-molecule inhibitor targeting TRIP13, DCZ0415, was capable of triggering synergistic cytotoxicity when combined with bortezomib in drug-resistant MM. This study identifies RPS3 as a novel biomarker and therapeutic target in MM.

Molecular mechanism by which RRM2-inhibitor (cholagogue osalmid) plus bafilomycin A1 cause autophagic cell death in multiple myeloma.

Despite significant improvement in the prognosis of multiple myeloma (MM), the disease remains incurable; thus, more effective therapies are required. Ribonucleoside-diphosphate reductase subunit M2 (RRM2) is significantly associated with drug resistance, rapid relapse, and poor prognosis. Previously, we found that 4-hydroxysalicylanilide (osalmid), a specific inhibitor of RRM2, exhibits anti-MM activity in vitro, in vivo, and in human patients; however, the mechanism remains unclear. Osalmid inhibits the translocation of RRM2 to the nucleus and stimulates autophagosome synthesis but inhibits subsequent autophagosome-lysosome fusion. We confirm that RRM2 binds to receptor-interacting protein kinase 3 (RIPK3) and reduces RIPK3, inhibiting autophagosome-lysosome fusion. Interestingly, the combination of osalmid and bafilomycin A1 (an autophagy inhibitor) depletes RIPK3 and aggravates p62 and autophagosome accumulation, leading to autophagic cell death. Combination therapy demonstrates synergistic cytotoxicity both in vitro and in vivo. Therefore, we propose that combining osalmid and bafilomycin A1(BafA1) may have clinical benefits against MM.

A novel alkaloid compound, DCZ0358, exerts significant antitumor activity in bortezomib-resistant multiple myeloma cells through inhibition of JAK2/STAT3 pathway.

Multiple myeloma (MM), the second most common haematological malignancy, is currently incurable because patients often develop multiple drug resistance and experience subsequent relapse of the disease. This study aims to identify a potential therapeutic agent that can counter bortezomib (BTZ) resistance in MM. DCZ0358, a novel alkaloid compound, is found to exert potent cytotoxic effects against BTZ-resistant MM cells in vivo and in vitro. The anti-myeloma activity of DCZ0358 is associated with inhibition of cell proliferation, promotion of cell apoptosis via caspase-mediated apoptotic pathways, and induction of G0/G1 phase arrest via downregulation of cyclin D1, CDK4, and CDK6. Further investigation of the molecular mechanism shows that DCZ0358 suppresses the JAK2/STAT3 signaling pathway. In conclusion, DCZ0358 can successfully counter BTZ resistance in MM cells. This study provides evidence that warrants future preclinical assessments of DCZ0358 as a therapeutic agent against BTZ resistance in MM.

Preclinical validation and phase I trial of 4-hydroxysalicylanilide, targeting ribonucleotide reductase mediated dNTP synthesis in multiple myeloma.

BACKGROUND: Aberrant DNA repair pathways contribute to malignant transformation or disease progression and the acquisition of drug resistance in multiple myeloma (MM); therefore, these pathways could be therapeutically exploited. Ribonucleotide reductase (RNR) is the rate-limiting enzyme for the biosynthesis of deoxyribonucleotides (dNTPs), which are essential for DNA replication and DNA damage repair. In this study, we explored the efficacy of the novel RNR inhibitor, 4-hydroxysalicylanilide (HDS), in myeloma cells and xenograft model. In addition, we assessed the clinical activity and safety of HDS in patients with MM. METHODS: We applied bioinformatic, genetic, and pharmacological approaches to demonstrate that HDS was an RNR inhibitor that directly bound to RNR subunit M2 (RRM2). The activity of HDS alone or in synergy with standard treatments was evaluated in vitro and in vivo. We also initiated a phase I clinical trial of single-agent HDS in MM patients (ClinicalTrials.gov: NCT03670173) to assess safety and efficacy. RESULTS: HDS inhibited the activity of RNR by directly targeting RRM2. HDS decreased the RNR-mediated dNTP synthesis and concomitantly inhibited DNA damage repair, resulting in the accumulation of endogenous unrepaired DNA double-strand breaks (DSBs), thus inhibiting MM cell proliferation and inducing apoptosis. Moreover, HDS overcame the protective effects of IL-6, IGF-1 and bone marrow stromal cells (BMSCs) on MM cells. HDS prolonged survival in a MM xenograft model and induced synergistic anti-myeloma activity in combination with melphalan and bortezomib. HDS also showed a favorable safety profile and demonstrated clinical activity against MM. CONCLUSIONS: Our study provides a rationale for the clinical evaluation of HDS as an anti-myeloma agent, either alone or in combination with standard treatments for MM. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03670173, Registered 12 September 2018.

DCZ0014, a novel compound in the therapy of diffuse large B-cell lymphoma via the B cell receptor signaling pathway.

Diffuse large B cell lymphoma (DLBCL) is a clinical and genetically heterogeneous lymphoid malignancy. Although R-CHOP (rituximab plus cyclophosphamide, vincristine, doxorubicin, and prednisone) treatment can improve the survival rate of patients with DLBCL, more than 30% of patients exhibit treatment failure, relapse, or refractory disease. Therefore, novel drugs or targeted therapies are needed to improve the survival of patients with DLBCL. The compound DCZ0014 is a novel chemical similar to berberine. In this study, we found that DCZ0014 significantly inhibited the proliferation and activity of DLBCL cells, and induced cell apoptosis. Following treatment with DCZ0014, DLBCL cells accumulated in G0/G1-phase of the cell cycle and showed decreased mitochondrial membrane potential. Additionally, DCZ0014 inhibited DNA synthesis, enhanced DNA damage in DLBCL cells, as well as inhibited Lyn/Syk in B cell receptor signaling pathway. Further experiments demonstrated that DCZ0014 did not significantly affect peripheral blood mononuclear cells. Tumor xenograft model showed that DCZ0014 not only inhibited tumor growth but also extended the survival time of mice. Thus, DCZ0014 showed potential for clinical application in the treatment of patients with DLBCL.

A novel silicone derivative of natural osalmid (DCZ0858) exerts anti-multiple myeloma activity by promoting cell apoptosis and inhibiting cell cycle and mTOR signaling.

Multiple myeloma (MM) is a malignant disease characterized by abnormal proliferation of clonal plasma cells. Based on the organic drug osalmid, the novel small molecule compound DCZ0858 was designed and synthesized for treating MM. DCZ0858 inhibited the proliferation and activity of MM cells and reduced colony formation. It also promoted the apoptosis of primary cells from patients with MM and cultured MM cell lines but had little effect on peripheral blood mononuclear cells in healthy people. Simultaneously, DCZ0858 activated caspase family proteins, blocked MM cells in G0/G1 phase, and reduced the expression of related cyclins CDK4/6 and CyclinD1. Moreover, DCZ0858 overcame the protective effect of the bone marrow microenvironment and effectively inhibited the activity of mTORC1 and mTORC2. Further, xenograft model experiments in mice showed that DCZ0858 significantly inhibited the proliferation and growth of tumors, with low drug toxicity. These results indicate that DCZ0858 has marked anti-MM activity and little effect on normal cells and tissues, making it a new candidate clinical drug for the treatment of MM.

Quercetin inhibits the proliferation of multiple myeloma cells by upregulating PTPRR expression.

Multiple myeloma (MM) is an incurable disease characterized by malignant plasma cell clonal expansion in the bone marrow; therefore, inhibiting the proliferation of plasma cells is an important approach to overcome the progression of MM. Quercetin (Que) is a promising flavonoid with broad-spectrum anti-tumor activity against various cancers, including MM; however, the underlying mechanism is not yet understood. The present study aimed to reveal the gene expression profile of Que-treated MM cells and clarify its potential mechanism. The 30% inhibitory concentration (IC30) of Que against MM cells was calculated, and the proliferation rate was significantly reduced after Que treatment. Next, 495 dysregulated genes were identified via RNA sequencing in Que-treated MM cells. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses indicated that the dysregulated genes were enriched in various apoptosis-related GO terms and amino acid metabolism-related pathways. qPCR validation showed that protein tyrosine phosphatase receptor-type R (PTPRR) had the highest verified log2 FC (abs) among the top 15 dysregulated genes. Overexpression of PTPRR increased the sensitivity of MM cells against Que, significantly inhibiting their proliferation and colony formation ability; silencing of PTPRR showed the opposite results. Furthermore, bioinformatics analyses and PPI network construction of PTPRR indicated that dephosphorylation of ERK might be the potential pathway for the PTPRR-induced inhibition of MM cell proliferation. In summary, our study identified the gene expression profile in Que-treated MM cells and demonstrated that the upregulation of PTPRR was one of the important mechanisms for the Que-induced inhibition of MM cell proliferation.

A novel phosphoramide compound, DCZ0805, shows potent anti-myeloma activity via the NF-κB pathway.

BACKGROUND: Multiple myeloma (MM) is a highly aggressive and incurable clonal plasma cell disease with a high rate of recurrence. Thus, the development of new therapies is urgently needed. DCZ0805, a novel compound synthesized from osalmide and pterostilbene, has few observed side effects. In the current study, we intend to investigate the therapeutic effects of DCZ0805 in MM cells and elucidate the molecular mechanism underlying its anti-myeloma activity. METHODS: We used the Cell Counting Kit-8 assay, immunofluorescence staining, cell cycle assessment, apoptosis assay, western blot analysis, dual-luciferase reporter assay and a tumor xenograft mouse model to investigate the effect of DCZ0805 treatment both in vivo and in vitro. RESULTS: The results showed that DCZ0805 treatment arrested the cell at the G0/G1 phase and suppressed MM cells survival by inducing apoptosis via extrinsic and intrinsic pathways. DCZ0805 suppressed the NF-κB signaling pathway activation, which may have contributed to the inhibition of cell proliferation. DCZ0805 treatment remarkably reduced the tumor burden in the immunocompromised xenograft mouse model, with no obvious toxicity observed. CONCLUSION: The findings of this study indicate that DCZ0805 can serve as a novel therapeutic agent for the treatment of MM.

Resveratrol induces AMPK and mTOR signaling inhibition-mediated autophagy and apoptosis in multiple myeloma cells.

Resveratrol, a natural compound extracted from the skins of grapes, berries, or other fruits, has been shown to have anti-tumor effects against multiple myeloma (MM) via promoting apoptosis and inhibiting cell viability. In addition to apoptosis, autophagy also plays a significant role in anti-tumor effects. However, whether autophagy is involved in anti-MM activity of resveratrol remains unclear. In this study, human MM cell lines U266, RPMI-8226, and NCI-H929 were treated with resveratrol. Cell Counting Kit-8 assay and colony formation assay were used to measure cell viability. Western blot analysis was used to detect apoptosis- and autophagy-associated proteins. 3-Methyladenine (3-MA) was applied to inhibit autophagy. Results showed that resveratrol inhibited cell viability and colony formation via promoting apoptosis and autophagy in MM cell lines U266, RPMI-8226, and NCI-H929. Resveratrol promoted apoptosis-related proteins, Caspase-3 activating poly-ADP-ribose polymerase and Caspase-3 cleavage, and decreased the protein level of Survivin in a dose-dependent manner. Additionally, resveratrol upregulated the levels of LC3 and Beclin1 in a dose-dependent way, indicating that autophagy might be implicated in anti-MM effect of resveratrol. Furthermore, 3-MA relieved the cytotoxicity of resveratrol by blocking the autophagic flux. Resveratrol increased the phosphorylation of adenosine monophosphate (AMP)-activated protein kinase and decreased the phosphorylation of mammalian target of rapamycin (mTOR) and its downstream substrates p70S6K and 4EBP1 in a dose-dependent manner, leading to autophagy. Therefore, our results suggest that resveratrol exerts anti-MM effects through apoptosis and autophagy, which can be used as a new therapeutic strategy for MM in clinic.

Anti-DLBCL efficacy of DCZ0825 in vitro and in vivo: involvement of the PI3K‒AKT‒mTOR/JNK pathway.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, characterized by high heterogeneity. The poor outcome of a portion of patients who suffer relapsing or resistant to conventional treatment impels the development of novel agents for DLBCL. DCZ0825 is a novel compound derived from pterostilbene and osalmide, whose antitumor activities have drawn our attention. In this study, we found that DCZ0825 exhibited high cytotoxicity toward DLBCL cell lines in a dose- and time-dependent manner, as revealed by cell counting kit-8 assay. Flow cytometry and western blot analysis results showed that DCZ0825 also promoted cell apoptosis via both extrinsic and intrinsic apoptosis pathways mediated by caspase. In addition, DCZ0825 induced cell cycle arrest in the G2/M phase by downregulating Cdc25C, CDK1, and Cyclin B1, thus interfering with cell proliferation. Further investigation showed the involvement of the phosphatidylinositol 3-kinase (PI3K)‒AKT‒mTOR/JNK pathway in the efficacy of DCZ0825 against DLBCL. Remarkably, DCZ0825 also exerted notable cytotoxic effects in vivo as well, with low toxicity to important internal organs such as the liver and kidney. Our results suggest that DCZ0825 may have the potential to become a novel anti-DLBCL agent or to replenish the conventional therapeutic scheme of DLBCL.

Glycolysis is suppressed by DCZ0801-induced inactivation of the Akt/mTOR pathway in Multiple Myeloma.

Multiple myeloma (MM) is a highly invasive and incurable plasma cell malignant disease with frequent recurrence. DCZ0801 is a natural compound synthesized from osalmide and pterostilbene and has few adverse effects. Here, we aimed to observe the therapeutic effects of DCZ0801 on myeloma cells and clarify the specific molecular mechanism underlying its anti-tumor activity. The Cell Counting Kit-8 assay, apoptosis detection, cell cycle analysis, western blot analysis, and tumor xenograft models were used to determine the effect of DCZ0801 treatment both in vivo and in vitro. We revealed that DCZ0801 treatment suppressed MM cell survival by inducing apoptosis and blocking the cell cycle at S phase. Deranged glycolysis and downregulated Akt/mTOR pathway may also be responsible for cell proliferation inhibition. Moreover, DCZ0801 treatment could remarkably reduce the tumor size in the xenograft mouse model. Therefore these findings indicate that DCZ0801 can be used as a novel therapeutic drug for patients suffering from multiple myeloma.

A novel M phase blocker, DCZ3301 enhances the sensitivity of bortezomib in resistant multiple myeloma through DNA damage and mitotic catastrophe.

BACKGROUND: DCZ3301, a novel aryl-guanidino compound previously reported by our group, exerts cytotoxic effects against multiple myeloma (MM), diffused large B cell lymphoma (DLBCL), and T-cell leukemia/lymphoma. However, the underlying mechanism of its action remains unknown. METHODS: We generated bortezomib (BTZ)-resistant cell lines, treated them with various concentrations of DCZ3301 over varying periods, and studied its effect on colony formation, cell proliferation, apoptosis, cell cycle, DNA synthesis, and DNA damage response. We validated our results using in vitro and in vivo experimental models. RESULTS: DCZ3301 overcame bortezomib (BTZ) resistance through regulation of the G2/M checkpoint in multiple myeloma (MM) in vitro and in vivo. Furthermore, treatment of BTZ-resistant cells with DCZ3301 restored their drug sensitivity. DCZ3301 induced M phase cell cycle arrest in MM mainly via inhibiting DNA repair and enhancing DNA damage. Moreover, DCZ3301 promoted the phosphorylation of ATM, ATR, and their downstream proteins, and these responses were blocked by the ATM specific inhibitor KU55933. CONCLUSIONS: Our study provides a proof-of-concept that warrants the clinical evaluation of DCZ3301 as a novel anti-tumor compound against BTZ resistance in MM.