Homologous to lymphotoxins, shows inducible expression, and competes with herpes simplex virus (HSV) glycoprotein D (gD) for herpes virus entry mediator (HVEM; TR2) (LIGHT), a ligand of herpes virus ...entry mediator (HVEM), increased reactive oxygen species (ROS) and enhanced the destruction of bacteria in human monocytes. In this study, rhLIGHT was found to increase the expression of the chemokine receptors, chemokine receptor 1 (CCR1) and CCR2, as well as to accelerate the migration activity of human monocytes. Additionally, rhLIGHT was found to increase ROS via NADPH oxidase p47
phox
phosphorylation, which was found to be required for LIGHT-induced NF-κB activation, CCR1 and CCR2 expression, migration and IL-8 and TNF-α production. Taken together, these results indicate that NADPH oxidase activation is required for rhLIGHT-induced migration in human monocytes.
Herpes virus entry mediator (HVEM) is a member of the TNF receptor (TNFR) superfamily and is expressed on many immune cells, including T and B cells, NK cells, monocytes, and neutrophils. Interaction ...of HVEM with its ligand, LIGHT, costimulates T cells and increases the bactericidal activity of monocytes and neutrophils. The interaction recruits cytoplasmic TNFR-associated factor adaptor proteins to the intracellular domain of HVEM. This leads to NFkappaB activation as a result of IkappaBalpha degradation and/or JNK/AP-1 activation, and ultimately results in the expression of genes required for cell survival, cytokine production, or cell proliferation. In this study, we show that treatment of human monocytes with recombinant human LIGHT (rhLIGHT) induces rapid elevation of intracellular calcium concentration (Ca(2+)(i)) in a HVEM-specific manner in parallel with TNF-alpha production, and enhances the bactericidal activities of monocytes. Immunoprecipitation and Western blotting analyses revealed phosphorylation of phospholipase Cgamma1 (PLCgamma1) but not PLCgamma2. rhLIGHT-induced Ca(2+)response was completely abolished by silencing PLCgamma1, or preincubating monocytes with PLC inhibitors, antagonists of the inositol-1,4,5-triphosphate receptor, or Ca(2+)(i) chelators. Furthermore, these PLC/Ca(2+) inhibitors also blocked rhLIGHT-mediated IkappaBalpha degradation, generation of reactive oxygen species, TNF-alpha production and the bactericidal activities of monocytes. Our results indicate that Ca(2+)is a downstream mediator of the LIGHT/HVEM interaction in monocytes.
Abstract
Background: Radotinib is a medicine for the treatment of some types of cancer. It is approved in South Korea for use as a second-line treatment of chronic myeloid leukemia (CML). Its ...mechanism of action involves inhibition of the tyrosine kinase Bcr-Abl and of platelet-derived growth factor receptor (PDGFR). It has been little known the effects of radotinib on multiple myeloma (MM) cells.
Methods: First, we examined cytotoxicity of radotinib on MM cell lines, RPMI-8226 and MM.1S. Annexin V positive cell, caspas-3 and -9 activities, cell cycle distribution and mitochondrial membrane potential (MMP, ΔΨm) were observed by analyzed with flow cytometric analysis. And diverse signaling pathways were investigated by Western blotting in MM cells.
Results: Interestingly, radotinib caused cell death of MM cells. Radotinib induced Annexin V positive cells, and caspase pathway activation including caspase-3, -7 and -9. And its treatment remarkably decreased MMP in MM cells. As well as we observed that cytochrome c accumulated dose dependently in the cytosol of radotinib-treated RPMI-8226 and MM.1S cells. Moreover, radotinib decreased the expression of Bcl-xL and Bcl-2, and increased the expression of Bax and Bak in MM cells. Moreover, radotinib significantly suppressed MM cell growth in a xenograft animal model using RPMI-8226 cells.
Conclusion: Radotinib may play an important role as a candidate or chemosensitizer for treatment agent in MM. These data indicate that radotinib has a potential for anti-cancer therapy in MM.
Figure 1. Radotinib significantly suppressed MM cell growth in a xenograft animal model using RPMI-8226 cells.
Citation Format: Jae-Cheol Jo, Sook-Kyoung Heo, Eui-Kyu Noh, Jeong Yi Kim, Jun Young Sung, Ho-Min Yu, Yoo Kyung Jeong, Lan Jeong Ju, Yunsuk Choi. Radotinib induces cell death of multiple myeloma cells abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1250.
Abstract
Background: Radotinib is a medicine for the treatment of some types of cancer. It is approved in South Korea for use as a second-line treatment of chronic myeloid leukemia (CML). Its ...mechanism of action involves inhibition of the tyrosine kinase Bcr-Abl and of platelet-derived growth factor receptor (PDGFR). It has been little known the effects of radotinib on mantle cell lymphoma cells (MCL). Methods: First, we examined cytotoxicity of radotinib on MCL cell line, MAVER-1 and REC-1. Also, cytotoxicity of radotinib on both cell lines which have a different genetic back ground. Annexin V positive cell, caspas-3 and -9 activities, cell cycle distribution and mitochondrial membrane potential (MMP) were observed by analyzed with flow cytometric analysis. And diverse signaling pathways were investigated by Western blotting in MCL cells.
Results: Interestingly, radotinib caused cell death of MCL cells. And radotinib induces G1-phase arrest in MAVER-1 and REC-1 cells. And it also inhibited the expression of CDK2, CDK4, and cyclin D1, D3 and E. Therefore, radotinib induces G1-phase arrest via suppression of CDK2, CDK4, and cyclin D1, D3 and E. Generally, the intrinsic apoptotic pathway involves mitochondrial activation and caspase and phosphatidylserine externalization. Radotinib induced Annexin V positive cells, and caspase pathway activation including caspase-3, -7 and -9. And its treatment remarkably decreased MMP in MCL cells at 72 h. As well as we observed that cytochrome c accumulated dose dependently in the cytosol of radotinib-treated MAVER-1 and REC-1 cells. Moreover, radotinib decreased the expression of Bcl-xL and Bcl-2, and increased the expression of Bax in MCL cells. These results indicate that radotinib induces cell death of MCL cells by induction of G1-phase arrest and mitochondrial-dependent apoptosis. Furthermore, the expression of p-AKT, AKT and ERK was significantly reduced by radotinib in MCL cells. Conclusion: Radotinib may play an important role as a candidate or chemosensitizer for treatment agent in MCL. These data indicate that radotinib has a potential for anti-cancer therapy in MCL.
Citation Format: Sook-Kyoung Heo, Eui-Kyu Noh, Yoo Kyung Jeong, Jeong Yi Kim, Yunsuk Choi, Jaekyung Cheon, SuJin Koh, Jin Ho Baek, Young Joo Min, Jae-Cheol Jo. Radotinib, a medicine for chronic myeloid leukemia, induces cell death of mantle cell lymphoma cells abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1621.
Background: LIGHT (Homologous to lymphotoxins, shows inducible expression, and competes with herpes simplex virus glycoprotein D for herpes virus entry mediator (HVEM)/tumor necrosis factor ...(TNF)-related 2, HVEM-L, TNFSF14, or CD258) is a member of TNF superfamily. It is expressed as a homotrimer on activated T cells and also on immune dendritic cells, and has three receptors such as HVEM, LT-¥â receptor (LT-¥âR) and decoy receptor 3 (DcR3). So far, three receptors with distinct cellular expression patterns are described to interact with LIGHT. Follicular DCs and stromal cells bind LIGHT through LT-¥âR. We monitored the effects of LIGHT on human bone marrow-derived mesenchymal stem cells (BM-MSCs).
Methods: At first, we checked negative and positive differentiation markers of BM-MSCs. After rhLIGHT treatment, we monitored cell count, viability, proliferation, and cell cycle distribution. Also, PDGF and TGF¥â production by rhLIGHT were examined by ELISA, and biological mechanism were checked by immunoblotting through the rhLIGHT treatment.
Results: FACS analysis result showed that LT-¥âR receptor is expressed in human BM-MSCs, but not HVEM indicating that LIGHT binds only LT-¥âR in human BM-MSCs. (Fig. 1A/B). rhLIGHT and LT-¥âR interaction increased cell numbers in BM-MSCs using an inverted microscope for cell number changes. Cell numbers by rhLIGHT enhanced dose-dependently and time-dependently (Fig. 2 A/B). Cell viability and the expression of p-AKT, Bcl-2 and Bcl-xL by rhLIGHT were significantly increased in BM-MSCs and rhLIGHT-induced IkB-¥á degradation activated NF-kB signal (Fig. 3A/B). rhLIGHT increased cell proliferation by increasing S/G2/M phase in BM-MSCs (Fig. 3C and 4D). And cell cycle regulatory proteins were enhanced by rhLIGHT in BM-MSC including cyclin B1, D1, D3, E, and cyclin dependent kinase (CDK) 1 and 2 while CDK inhibitor, p27 was decreased by rhLIGHT treatment (Fig. 3E). Moreover, rhLIGHT-induced PDGF and TGF¥â production by STAT3 and smad3 activation accelerated BM-MSCs proliferation. And we also confirmed differentiation potential of rhLIGHT on BM-MSCs by the staining for adipogenesis (Oil Red O staining), chondrogenesis (Alcian blue staining) and Osteogenesis (Alizarin red Staining).
Conclusion: LIGHT and LT-¥âR interaction increases survival and proliferation of human BM-MSCs by activation of survival proteins, anti-apoptotic proteins, CDKs and cyclins. Moreover, LIGHT-induced STAT-3 and smad-3 activation causes PDGF and TGF-¥â production, and they enhance LIGHT signals in human BM-MSCs. We proposed the pathway of LIGHT and LT-¥âR interaction in human BM-MSCs. Therefore, LIGHT may play an important role for therapy of stem cells, and contribute to modification of MSCs.
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No relevant conflicts of interest to declare.
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