Lycorine targets multiple myeloma stem cell-like cells by inhibition of Wnt/β-catenin pathway

Targeting cancer stem cells in multiple myeloma

Multiple myeloma (MM) is a hematological malignancy of bone marrow (BM) plasma cells with excessive clonal expansion and is associated with the overproduction of light-chain or monoclonal immunoglobulins (Igs). MM remains incurable, with high rates of relapses and refractory disease after first-line treatment. Cancer stem cells (CSCs) have been implicated in drug resistance in MM; however, the evidence for CSCs in MM is not adequate, partly due to a lack of uniformity in the definitions of multiple myeloma stem cells (MMSCs). We review advances in understanding MMSCs and their role in drug resistance to MM therapies. We also discuss novel therapeutic strategies to overcome MMSC-mediated relapses and drug resistance.

Interleukin-33 increases the sensitivity of multiple myeloma cells to the proteasome inhibitor bortezomib through reactive oxygen species-mediated inhibition of nuclear factor kappa-B signal and stemness properties

The proteasome inhibitor bortezomib (BTZ) is the first-line therapy for multiple myeloma (MM). BTZ resistance largely limits its clinical application in MM. Interleukin-33 (IL-33) exerts antitumor effects through various mechanisms, including enhancing antitumor immunity and promoting the apoptosis of cancer cells. Here, the synergistic anti-MM effect of IL-33 and BTZ was verified, and the underlying mechanisms were elucidated. Bioinformatic analysis indicated that IL-33 expression levels were downregulated in MM, and that BTZ-treated MM patients with high IL-33 levels had better prognosis than those with low IL-33 levels. Moreover, the patients with high IL-33 levels had a better treatment response to BTZ. Further immune analysis suggested that IL-33 can enhance the anti-MM immunity. IL-33 and BTZ synergistically inhibited proliferation and induced apoptosis of MM cells, which was mediated by the excessive accumulation of cellular reactive oxygen species (ROS). Furthermore, increased ROS hindered the nuclear translocation of NF-κB-p65, thereby decreasing the transcription of target stemness-related genes (SOX2, MYC, and OCT3/4). These effects induced by the combination therapy could be reversed by eliminating ROS by N-acetylcysteine. In conclusion, our results indicated that IL-33 enhanced the sensitivity of MM to BTZ through ROS-mediated inhibition of nuclear factor kappa-B (NF-κB) signal and stemness properties.

Lycorine eliminates B-cell acute lymphoblastic leukemia cells by targeting PSAT1 through the serine/glycine metabolic pathway

B-cell acute lymphoblastic leukemia (B-ALL) has been confirmed as the most common malignant hematologic neoplasm among children. A novel antitumor mechanism of lycorine was elucidated in this study. As revealed by the result of this study, lycorine significantly inhibited the growth and proliferation of REH and NALM-6 and induced their apoptosis. The result of the RNA-seq analysis suggested that lycorine targeted PSAT1 of serine/glycine metabolism in B-ALL cells. As indicated by the result of the GSEA analysis, the genes enriched in the amino acid metabolic pathways were down-regulated by lycorine. As revealed by the results of ectopic expression, shRNA knockdown assays, and further liquid-phase tandem mass spectrometry (LC-MS) analysis, lycorine reduced serine/glycine metabolites by down-regulating PSAT1, further disrupting carbon metabolism and eliminating B-ALL cells. Furthermore, lycorine showed a synergistic effect with cytarabine in ALL treatments. Lastly, lycorine significantly down-regulated leukemia progression in the cell line-derived xenograft (CDX) model. In brief, this study has suggested for the first time that lycorine is a promising anti-ALL drug, and a novel amino acid metabolism-associated property of lycorine was identified.

METTL3 facilitates multiple myeloma tumorigenesis by enhancing YY1 stability and pri-microRNA-27 maturation in m6A-dependent manner

Multiple myeloma (MM) is a pernicious plasma cell disorder and has a poor prognosis. N6-methyladenosine (m6A) is an abundant epigenetic RNA modification and is important in cancer progression. Nevertheless, the function of m6A and its regulator METTL3 in MM are rarely reported. Here, we identified the m6A "writers", METTL3, was enhanced in MM and found that Yin Yang 1 (YY1) and primary-miR-27a-3p were the potential target for METTL3. METTL3 promoted primary-miR-27a-3p maturation and YY1 mRNA stability in an m6A manner. YY1 also was found to facilitate miR-27a-3p transcription. METTL3 affected the growth, apoptosis, and stemness of MM cells through accelerating the stability of YY1 mRNA and the maturation of primary-miR-27a-3p in vitro and in vivo. Our results reveal the key function of the METTL3/YY1/miR-27a-3p axis in MM and may provide fresh insights into MM therapy.

The Wnt/β-catenin signalling pathway in Haematological Neoplasms

Leukaemia and lymphoma are common malignancies. The Wnt pathway is a complex network of proteins regulating cell proliferation and differentiation, as well as cancer development, and is divided into the Wnt/β-catenin signalling pathway (the canonical Wnt signalling pathway) and the noncanonical Wnt signalling pathway. The Wnt/β-catenin signalling pathway is highly conserved evolutionarily, and activation or inhibition of either of the pathways may lead to cancer development and progression. The aim of this review is to analyse the mechanisms of action of related molecules in the Wnt/β-catenin pathway in haematologic malignancies and their feasibility as therapeutic targets.

Cold Atmospheric Plasma Suppressed MM In Vivo Engraftment by Increasing ROS and Inhibiting the Notch Signaling Pathway

Multiple myeloma (MM) is the second most common hematologic malignancy. MM stem cells (MMSCs) are thought to be the main causes of in vivo engraftment and eventual recurrence. As a notable new technology, cold atmospheric plasmas (CAPs) show a promising anti-tumor effect, due to their production of various ROS. In this study, we found that different types of plasma could inhibit MM’s ability to form cell colonies, suppress MM in vivo engraftment, and extend survival times. We demonstrated that NAC (a ROS scavenger) could block ROS increases and reverse the inhibition of MM’s cell-colony-formation ability, which was induced by the plasma treatment. By using a stem cell signaling array, we found that the Notch pathway was inhibited by the plasma treatment; this was further confirmed by conducting real-time PCRs of three MM cell lines. Together, these results constitute the first report of plasma treatment inhibiting MM in vivo engraftment and prolonging survival time by suppressing the Notch pathway via ROS regulation.

Lycorine ameliorates isoproterenol-induced cardiac dysfunction mainly via inhibiting inflammation, fibrosis, oxidative stress and apoptosis

Alleviating cardiac dysfunction improves the prognosis of heart failure patients. Lycorine is an alkaloid with several beneficial biological properties. Here, we used mice to evaluate the effect of lycorine on cardiac dysfunction elicited by isoproterenol. Mice were divided into four groups: control, lycorine, isoproterenol, and isoproterenol + lycorine. Mice in the combined group were treated daily with 10 mg/kg isoproterenol intraperitoneally for 2 weeks and 5 mg/kg lycorine was given simultaneously intraperitoneally for 4 weeks. Cardiac structure and function were assessed by echocardiography, hematoxylin and eosin staining, and Masson's trichrome staining. Isoproterenol-induced cardiac dysfunction and histopathological injury that was significantly improved by treatment with lycorine. Western blotting and the quantitative real-time polymerase chain reaction were used to explore the molecular mechanisms of these effects. Levels of the inflammatory cytokines, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, were increased by treatment with isoproterenol; these increases were significantly reduced by lycorine, with involvement of the NF-κB signaling pathway. The fibrotic factors, collagen I and collagen III, were increased by isoproterenol and decreased by treatment with lycorine through inhibiting activation of the Smad signaling pathway. In addition, lycorine alleviated oxidative stress as evidenced by a reduction in total reactive oxygen species in the isoproterenol + lycorine group compared to the isoproterenol group. Lycorine exerted an anti-apoptotic effect as evidenced by upregulating Bcl-2 and downregulating Bax. Overall, our findings demonstrate that lycorine protects against cardiac dysfunction induced by isoproterenol by inhibiting inflammation, fibrosis, oxidative stress, and apoptosis.

Cyclin-dependent kinase 1 as a potential target for lycorine against hepatocellular carcinoma

The pathological changes and possible underlying molecular mechanisms of hepatocellular carcinoma (HCC) are currently unclear. Effective treatment of this pathological state remains a challenge. The purpose of this study is to obtain some key genes with diagnostic and prognostic meaning and to identify potential therapeutic agents for HCC treatment. Here, CDK1, CCNB1 and CCNB2 were found to be highly expressed in HCC patients and accompanied by poor prognosis, and knockdown of them by siRNA drastically induced autophagy and senescence in hepatoma cells. Simultaneously, the anti-HCC effect of lycorine was comparable to that of interfering with these three genes, and lycorine significantly promoted the decrease both in protein and mRNA expression of CDK1. Molecular validation mechanistically demonstrated that lycorine might attenuate the degradation rate of CDK1 via interaction with it, which had been confirmed by cellular thermal shift assay and drug affinity responsive targets stability assay. Taken together, these findings suggested that CDK1, CCNB1 and CCNB2 could be regarded as potential diagnostic and prognostic biomarkers for HCC, and CDK1 might serve as a promising therapeutic target for lycorine against HCC.

Ferroptosis is involved in the anti-tumor effect of lycorine in renal cell carcinoma cells

Renal cell carcinoma (RCC) is a most common malignant tumor in the genitourinary system. Studies have shown that Lycorine has promising anticancer activities with minor side effects. However, the effect of lycorine on the proliferation of RCC cells and its underlying anti-tumor mechanism have not yet been fully elucidated. The human renal cancer cell lines 786-O, A498 and Caki-1 were cultured and treated with different concentrations of lycorine or ferrostatin-1, a ferroptosis inhibitor. Cell viability and colony formation assays were used to measure cell proliferation. The 5-, 12- and 15-HETE hydroxyeicosatetraenoic acid (HETE) and MDA levels, as well as the reduced to oxidized glutathione (GHS/GSSG) ratio, were analyzed. Western blot analysis was used to detect the expression of glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase long chain family member 4 (ACSL4), which are key markers of ferroptosis. Transmission electron microscopy was used to observe the morphological features associated with ferroptosis. Lycorine was found to inhibit the proliferation of RCC cells. After lycorine treatment, the expression levels of GPX4 in RCC cells decreased, whereas those of ACSL4 increased. Lycorine induced the expression of 5-HETE, 12-HETE, 15-HETE and MDA in RCC cells, and reduced the GSH/GSSG ratio. In addition, ferrostatin-1 could prevent lycorine-induced ferroptosis in RCC cells.

Albendazole inhibits NF-κB signaling pathway to overcome tumor stemness and bortezomib resistance in multiple myeloma

Multiple myeloma (MM) is incurable and the second most common hematologic malignancy in plasma cells. Multiple myeloma stem cell-like cells (MMSCs), a rare population of MM cells, are believed to be the major cause of drug resistance and high recurrence rates in patients with MM. Therefore, developing novel strategies to eradicate MMSCs may favor myeloma treatment. In this study, based on the drug repositioning strategy, we found that albendazole (ABZ), a broad-spectrum antiparasitic drug, selectively suppresses the proliferation of multiple myeloma cells in vitro and in vivo and decreases number of aldehyde dehydrogenase (ALDH)-positive MMSCs in MM. Furthermore, RNA-seq of MM cells after ABZ treatment revealed that inhibition of the nuclear factor kappa-B (NF-κB) pathway is a key mediator of ABZ against MM. Moreover, we demonstrated that ABZ can resensitize cells resistant to bortezomib and overcome MMSCs-induced bortezomib resistance by decreasing ALDH1⁺ MMSCs numbers. Our findings provide preclinical evidence for utilizing the previously known pharmacologically active drug albendazole for the treatment of multiple myeloma.

Identification and Characterization of Multiple Myeloma Stem Cell-Like Cells

Multiple myeloma (MM) is a B-cell tumor of the blood system with high incidence and poor prognosis. With a further understanding of the pathogenesis of MM and the bone marrow microenvironment, a variety of adjuvant cell therapies and new drugs have been developed. However, the drug resistance and high relapse rate of MM have not been fundamentally resolved. Studies have shown that, in patients with MM, there is a type of poorly differentiated progenitor cell (MM stem cell-like cells, MMSCs). Although there is no recognized standard for identification and classification, it is confirmed that they are closely related to the drug resistance and relapse of MM. This article therefore systematically summarizes the latest developments in MMSCs with possible markers of MMSCs, introduces the mechanism of how MMSCs work in MM resistance and recurrence, and discusses the active pathways that related to stemness of MM.

Iguratimod-encapsulating PLGA-NPs induce human multiple myeloma cell death via reactive oxygen species and Caspase-dependent signalling

Human multiple myeloma (MM) is a currently incurable haematopoietic malignancies. Our research investigate the anti-tumour effect of iguratimod (IGU) encapsulated in poly(lactic-co-glycolic acid) PLGA nanoparticles (IGU-PLGA-NPs) on MM cells in vitro and in vivo. A significant inhibitory effect of IGU-PLGA-NPs on MM cancer cells and MM CSCs was demonstrated by the Cell Counting Kit-8 (CCK-8) assay. Treatment with IGU-PLGA-NPs induced significant cell cycle arrest at G1 in MM cells and reduced tumour colony formation in MM CSCs. Mechanistically, IGU-PLGA-NPs increase apoptosis in MM cells by activating Caspase-dependent signalling pathway to increase the levels of bax, cytochrome c (cyt-c), caspase-9 and caspase-3 proteins. Moreover, IGU-PLGA-NPs effectively increase ROS production assayed using a DCFH-DA fluorescent probe in MM cells. The data indicate that IGU-PLGA-NPs induce a significant reduction in the tumour volume and a marked increase in the survival rate in a mouse model of multiple myeloma. Overall, our findings indicate that IGU-PLGA-NPs are a potential therapeutic strategy that may contribute to the therapy of MM and elimination of MM CSCs in future clinical trials.

Multiple Myeloma Inhibitory Activity of Plant Natural Products

A literature search on plant natural products with antimyeloma activity until the end of 2020 resulted in 92 compounds with effects on at least one human myeloma cell line. Compounds were divided in different compound classes and both their structure-activity-relationships as well as eventual correlations with the pathways described for Multiple Myeloma were discussed. Each of the major compound classes in this review (alkaloids, phenolics, terpenes) revealed interesting candidates, such as dioncophyllines, a group of naphtylisoquinoline alkaloids, which showed pronounced and selective induction of apoptosis when substituted in position 7 of the isoquinoline moiety. Interestingly, out of the phenolic compound class, two of the most noteworthy constituents belong to the relatively small subclass of xanthones, rendering this group a good starting point for possible further drug development. The class of terpenoids also provides noteworthy constituents, such as the highly oxygenated diterpenoid oridonin, which exhibited antiproliferative effects equal to those of bortezomib on RPMI8226 cells. Moreover, triterpenoids containing a lactone ring and/or quinone-like substructures, e.g., bruceantin, whitaferin A, withanolide F, celastrol, and pristimerin, displayed remarkable activity, with the latter two compounds acting as inhibitors of both NF-κB and proteasome chymotrypsin-like activity.

JMJD2C triggers the growth of multiple myeloma cells via activation of β‑catenin

Emerging evidence has indicated that histone modification and its related regulators are involved in the progression of multiple myeloma (MM) cells. In the present study, the expression of Jumonji C domain‑containing 2 (JMJD2) was examined in both MM tissues and healthy controls. The roles of JMJD2C in the progression of MM were further investigated. The results revealed that the expression of JMJD2C, but not that of JMJD2A or JMJD2B, was increased in MM tissues compared with the healthy controls. The overexpression of JMJD2C significantly increased the in vitro growth of MM cells. The inhibitor of the β‑catenin signaling pathway significantly attenuated the JMJD2C‑induced growth of MM cells. Mechanistical analyses indicated that JMJD2C increased the transcription of β‑catenin in MM cells, which may be due to the fact that JMJD2C can directly bind with the promoter of β‑catenin. Furthermore, JMJD2C activated β‑catenin in MM cells via a GSK3β‑dependent manner, which was evidenced by the results demonstrating that the overexpression of GSK3β attenuated the JMJD2C‑induced decrease in the phosphorylation of β‑catenin. On the whole, the findings of the present study demonstrated that JMJD2C promotes the malignancy of MM via the activation of the β‑catenin pathway. These results suggested that JMJD2C may be a potential target for MM treatment.