Green tea polyphenols block the anticancer effects of bortezomib and other boronic acid–based proteasome inhibitors

Blood ◽  
2009 ◽  
Vol 113 (23) ◽  
pp. 5927-5937 ◽  
Author(s):  
Encouse B. Golden ◽  
Philip Y. Lam ◽  
Adel Kardosh ◽  
Kevin J. Gaffney ◽  
Enrique Cadenas ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Tumor Cell ◽  
Green Tea ◽  
Boronic Acid ◽  
Proteasome Inhibitors ◽  
Green Tea Polyphenols ◽  
Tumor Cell Death

Abstract The anticancer potency of green tea and its individual components is being intensely investigated, and some cancer patients already self-medicate with this “miracle herb” in hopes of augmenting the anticancer outcome of their chemotherapy. Bortezomib (BZM) is a proteasome inhibitor in clinical use for multiple myeloma. Here, we investigated whether the combination of these compounds would yield increased antitumor efficacy in multiple myeloma and glioblastoma cell lines in vitro and in vivo. Unexpectedly, we discovered that various green tea constituents, in particular (-)-epigallocatechin gallate (EGCG) and other polyphenols with 1,2-benzenediol moieties, effectively prevented tumor cell death induced by BZM in vitro and in vivo. This pronounced antagonistic function of EGCG was evident only with boronic acid–based proteasome inhibitors (BZM, MG-262, PS-IX), but not with several non–boronic acid proteasome inhibitors (MG-132, PS-I, nelfinavir). EGCG directly reacted with BZM and blocked its proteasome inhibitory function; as a consequence, BZM could not trigger endoplasmic reticulum stress or caspase-7 activation, and did not induce tumor cell death. Taken together, our results indicate that green tea polyphenols may have the potential to negate the therapeutic efficacy of BZM and suggest that consumption of green tea products may be contraindicated during cancer therapy with BZM.

scholarly journals Dominant-negative ATF5 rapidly depletes survivin in tumor cells

2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Xiaotian Sun ◽  
James M. Angelastro ◽  
David Merino ◽  
Qing Zhou ◽  
Markus D. Siegelin ◽  
...  
Keyword(s):  
Cell Death ◽  
Tumor Cell ◽  
Cancer Cells ◽  
Dominant Negative ◽  
Tumor Cell Death ◽  
Cell Penetrating ◽  
Selective Death ◽  
Tumor Types

Abstract Survivin (BIRC5, product of the BIRC5 gene) is highly expressed in many tumor types and has been widely identified as a potential target for cancer therapy. However, effective anti-survivin drugs remain to be developed. Here we report that both vector-delivered and cell-penetrating dominant-negative (dn) forms of the transcription factor ATF5 that promote selective death of cancer cells in vitro and in vivo cause survivin depletion in tumor cell lines of varying origins. dn-ATF5 decreases levels of both survivin mRNA and protein. The depletion of survivin protein appears to be driven at least in part by enhanced proteasomal turnover and depletion of the deubiquitinase USP9X. Survivin loss is rapid and precedes the onset of cell death triggered by dn-ATF5. Although survivin downregulation is sufficient to drive tumor cell death, survivin over-expression does not rescue cancer cells from dn-ATF5-promoted apoptosis. This indicates that dn-ATF5 kills malignant cells by multiple mechanisms that include, but are not limited to, survivin depletion. Cell-penetrating forms of dn-ATF5 are currently being developed for potential therapeutic use and the present findings suggest that they may pose an advantage over treatments that target only survivin.

scholarly journals IFN-γ down-regulates Hsp27 and enhances hyperthermia-induced tumor cell death in vitro and tumor suppression in vivo

2008 ◽  
Author(s):  
Mariko Oba ◽  
Shuichiro Yano ◽  
Tsuyoshi Shuto ◽  
Mary Suico ◽  
Ayaka Eguma ◽  
...  
Keyword(s):  
Cell Death ◽  
Tumor Cell ◽  
Tumor Suppression ◽  
Tumor Cell Death ◽  
Ifn Γ

scholarly journals 18F-C2Am: a targeted imaging agent for detecting tumor cell death in vivo using positron emission tomography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Flaviu Bulat ◽  
Friederike Hesse ◽  
De-En Hu ◽  
Susana Ros ◽  
Connor Willminton-Holmes ◽  
...  
Keyword(s):  
Cell Death ◽  
Tumor Cell ◽  
Treatment Response ◽  
Human Tumor ◽  
Cysteine Residue ◽  
Tumor Cell Death ◽  
One Pot ◽  
Synthesis Time

Abstract Introduction Trialing novel cancer therapies in the clinic would benefit from imaging agents that can detect early evidence of treatment response. The timing, extent and distribution of cell death in tumors following treatment can give an indication of outcome. We describe here an 18F-labeled derivative of a phosphatidylserine-binding protein, the C2A domain of Synaptotagmin-I (C2Am), for imaging tumor cell death in vivo using PET. Methods A one-pot, two-step automated synthesis of N-(5-[18F]fluoropentyl)maleimide (60 min synthesis time, > 98% radiochemical purity) has been developed, which was used to label the single cysteine residue in C2Am within 30 min at room temperature. Binding of 18F-C2Am to apoptotic and necrotic tumor cells was assessed in vitro, and also in vivo, by dynamic PET and biodistribution measurements in mice bearing human tumor xenografts treated with a TRAILR2 agonist or with conventional chemotherapy. C2Am detection of tumor cell death was validated by correlation of probe binding with histological markers of cell death in tumor sections obtained immediately after imaging. Results 18F-C2Am showed a favorable biodistribution profile, with predominantly renal clearance and minimal retention in spleen, liver, small intestine, bone and kidney, at 2 h following probe administration. 18F-C2Am generated tumor-to-muscle (T/m) ratios of 6.1 ± 2.1 and 10.7 ± 2.4 within 2 h of probe administration in colorectal and breast tumor models, respectively, following treatment with the TRAILR2 agonist. The levels of cell death (CC3 positivity) following treatment were 12.9–58.8% and 11.3–79.7% in the breast and colorectal xenografts, respectively. Overall, a 20% increase in CC3 positivity generated a one unit increase in the post/pre-treatment tumor contrast. Significant correlations were found between tracer uptake post-treatment, at 2 h post-probe administration, and histological markers of cell death (CC3: Pearson R = 0.733, P = 0.0005; TUNEL: Pearson R = 0.532, P = 0.023). Conclusion The rapid clearance of 18F-C2Am from the blood pool and low kidney retention allowed the spatial distribution of cell death in a tumor to be imaged during the course of therapy, providing a rapid assessment of tumor treatment response. 18F-C2Am has the potential to be used in the clinic to assess early treatment response in tumors.

scholarly journals EXTH-44. INHIBITION OF MerTK ACTIVATES GLIOBLASTOMA-ASSOCIATED MACROPHAGES AND INDUCES TUMOR CELL DEATH IN GLIOMA MICROENVIRONMENT

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi91-vi91
Author(s):  
Yu-Ting Su ◽  
Madison Butler ◽  
Lee Hwang ◽  
Dragan Maric ◽  
Shelton Earp ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Growth ◽  
Tumor Microenvironment ◽  
Tumor Cell ◽  
Colony Formation ◽  
Glioblastoma Cells ◽  
Tumor Cell Death ◽  
Glioma Microenvironment

Abstract BACKGROUND Glioblastoma-associated macrophages and microglia (GAMs) are the predominant immune cells in the tumor microenvironment. Activation of MerTK, a receptor tyrosine kinase, triggers efferocytosis and polarizes GAMs to an immunosuppressive phenotype, promoting glioma growth. Our previous findings showed that UNC2371, a small-molecule inhibitor of MerTK, induced a less immunosuppressive phenotype of GAMs. Here, we investigate the role of MerTK inhibition on glioblastoma cells in the tumor microenvironment in vitro and in vivo. METHODS Cytotoxicity of UNC2371 in glioblastoma cells was determined by cell viability and colony formation assays. The protein expression of MerTK, AKT, and Erk were quantified by Western blotting in UNC2371-treated glioblastoma cells. A syngeneic GL261 mouse orthotopic glioblastoma model was used to evaluate the survival benefit of UNC2371 treatment. Fluorescent multiplex immunohistochemistry (IHC) was used to evaluate the expression of CD206, an anti-inflammatory marker on GAMs in murine brain tumor tissues. RESULTS UNC2371 inhibited GBM cell growth with an EC50 < 100 nM in both human U251 and mouse GL261 glioma cells, but not in GAMs. UNC2371-induced cell death and decreased cell proliferation were demonstrated by colony formation assays. UNC2371 decreased protein expression of phosphorylated MerTK, AKT, and Erk, which are essential for cell survival signaling, in U251 and GL261 cells. Furthermore, UNC2371 treatment prolonged survival in the mouse orthotopic GL261 glioblastoma model, suggesting that UNC2371 induces glioma cell death. A decreased of CD206+ GAMs was found in mice glioma tissues by fluorescent multiplex IHC, consistent with our previous findings in the in vitro cell-based assays. These data suggest that in addition to alleviate immunosuppression in the glioma microenvironment, UNC2371 directly inhibits GBM cell growth in vitro and in vivo. CONCLUSION Our findings suggest that UNC2371 has a therapeutic benefit via promoting GAM polarization towards proinflammatory status in the glioblastoma microenvironment and unexpectedly, inducing tumor cell death.

In Vitro and In Vivo Efficacy of a Novel Orally Bioavailable Beta-Catenin Inhibitor-BC2059- As Monotherapy or in Combination with Proteasome Inhibitors in Multiple Myeloma

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1816-1816
Author(s):  
Ioanna Savvidou ◽  
Tiffany T. Khong ◽  
Stephen K. Horrigan ◽  
Andrew Spencer
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Single Agent ◽  
Proteasome Inhibitors ◽  
Canonical Pathway ◽  
Beta Catenin ◽  
Dependent Manner ◽  
Canonical Wnt

Abstract Background: The currently available treatment options are unlikely to be curative for the majority of Multiple Myeloma (MM) patients, emphasizing a continuing role for the introduction of investigational agents that overcome drug resistance. The canonical Wnt/β-catenin signalling pathway has been found to be dysregulated in MM, and its activation is associated with advanced stage MM, providing a rationale to evaluate the novel β-catenin inhibitor BC2059 in mono- and combination therapy with proteasome inhibitors in vitro and in vivo. Methods and Results: We evaluated the activation status of the canonical Wnt pathway in 12 genetically heterogeneous Human Myeloma Cell Lines (HMCL) by assessing the expression of β-catenin protein in the nuclear compartment (active form). This showed that nuclear β-catenin was present in all HMCL tested and absent in plasma cells derived from a healthy donor. Moreover, additional stimulation of the canonical pathway with rhWnt3a was shown to be pro-proliferative, in contrast, no proliferation was seen with activation of the non canonical pathway following treatment with rhWnt5a. BC2059 (50nM to 500nM) induced apoptosis of all 12 HMCL and was able to inhibit the proliferation of all HMCL tested in a dose and time dependent manner assessed by MTS assay and viable enumeration with trypan blue (IC50: 53nM to 247nM). Mimicking the bone marrow (BM) microenvironment by co-culturing HMCL with the immortalised human stromal cell line HS-5, BC2059 was able to overcome the protective effect of HS-5 (for example KMS18 at IC90=220nM had no stromal pro-survival effect). Similarly, BC2059 was able to abolish the pro-proliferative effect of rh-Wnt3a or conditioned media derived from MM patients' BM when used at doses >100nM or 50nM, respectively. BC2059 facilitated the degradation of β-catenin protein in the nuclear cellular compartment ( >50% decrease of nuclear β-catenin in KMS18 treated with 1.5xIC50 when compared with untreated cells), furthermore, using a reporter assay we showed that BC2059 inhibited TCF/LEF transcriptional activity in a dose-dependent manner and decreased the transcription of axin2, a down-stream target gene of β-catenin - 78% reduction in KMS18 cells treated with 1.5x IC50 when compared to untreated controls. BC2059-induced HMCL cell death was associated with activation of both the intrinsic and extrinsic caspase-dependent apoptotic pathways, as shown by the accumulation of the activated forms of caspases 8, 9 and 3 following BC2059 treatment. However, inhibition of the caspase-pathway by the addition of caspase inhibitors (pan-caspase inhibitor Z-VAD, and caspase-3 inhibitor Z-DEVD) could not abolish the pro-necrotic effect of BC2059 or BC2059 plus bortezomib, suggesting a possible role for autophagy-induced cell death. As β-catenin undergoes proteasome-mediated destruction and has been found to increase following bortezomib treatment, we evaluated the effect of combining BC2059 with Bortezomib. The combination was synergistic for 6/8 HMCL tested (e.g. for LP1 CI:0.64-0.55, where CI<1.1=synergism). We also evaluated the effect of the combination of BC2059 with next generation proteasome inhibitors (carfilzomib and marizomib) where it was shown to have synergistic and/or additive effects (e.g. for carfilzomib LP1 CI:0.33-0.99). Single agent BC2059 effectively killed primary MM tumour cells from relapsed/refractory MM patients (n=13) and the combination with bortezomib was synergistic (n=2) with no effect on healthy peripheral blood mononuclear cells (n=4). Finally, BC2059 (10mg/kg) prolonged survival of xenografted NSG mice compared to untreated controls with no major side effects in Wnt/β-catenin dependent tissues (GI track and haematopoiesis). Conclusion: We have demonstrated that BC2059 at nano-molar concentrations has a strong anti-MM effect both in vitro and in vivo and synergises with proteasome inhibitors. These data strongly support the clinical evaluation of BC2059 for the treatment of MM. Disclosures Horrigan: BetaCat Pharmaceuticals: Employment.

Insights into the Biological Evaluation of Pterocarpanquinones and Carbapterocarpans with Anti-tumor Activity against MDR Leukemias

2019 ◽  
Vol 19 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Vivian M. Rumjanek ◽  
Raquel C. Maia ◽  
Eduardo J. Salustiano ◽  
Paulo R.R. Costa
Keyword(s):  
Cell Death ◽  
Tumor Cell ◽  
Cell Lines ◽  
Biological Evaluation ◽  
Ehrlich Carcinoma ◽  
Tumor Cell Lines ◽  
Tumor Cell Death ◽  
Mitochondrial Membrane Depolarization

In an attempt to find anticancer agents that could overcome multidrug resistance (MDR), two new classes of modified isoflavonoids were designed and synthesized, and their effectiveness evaluated against a vast array of tumor cell lines. Pterocarpanquinone (LQB-118) and 11a-aza-5-carbapterocarpan (LQB-223) were the most promising. LQB-118 induced cell death, in vitro, in the &#181;M range, to a number of human cancer cell lines as well as to fresh tumor cells obtained from patients with acute or chronic myeloid leukemia, independent on whether they exhibit the MDR phenotype or not. Furthermore, leukemic cells were more sensitive to LQB- 118 compared to cells from solid tumors. Given to mice, in vivo, LQB-118 affected the growth of melanoma, Ehrlich carcinoma and prostate cancer cells. Conversely, no general toxicity was observed in vivo, by biochemical, hematological, anatomical or histological parameters and toxicity in vitro against normal cells was low. The process involved in tumor cell death seemed to vary according to cell type. Apoptosis was studied by externalization of phosphatidylserine, DNA fragmentation, caspase-3 activation, reduced expression of XIAP and survivin, ER stress, cytosolic calcium increase and mitochondrial membrane depolarization. Autophagy was also evaluated inhibiting caspase-9, with no effect observed in beclin 1, whereas pre-treatment with rapamycin increased cytotoxicity induced by LQB-118. In addition, LQB-118 increased ROS, inhibited NF&#954;B nuclear translocation and secretion of TNF-&#945;, modulated microRNAs miR-9 and miR-21 and modified the cell cycle. Despite being less studied, the cytotoxic effect of the 11a-aza-5-carbapterocarpan LQB-223 was present against several tumor cell lines, including those with the MDR phenotype.

scholarly journals Proteasome Inhibitors Block Myeloma-Induced Osteocyte Death in Vitro and in Vivo in Multiple Myeloma Patients

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3978-3978
Author(s):  
Denise Toscani ◽  
Benedetta Dalla Palma ◽  
Carla Palumbo ◽  
Marzia Ferretti ◽  
Marina Bolzoni ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Positive Impact ◽  
Proteasome Inhibitors ◽  
Percent Change ◽  
Significant Difference ◽  
Bone Biopsies ◽  
Osteocyte Death

Abstract Abstract 3978 Multiple myeloma (MM) is characterized by a severe unbalanced and uncoupling bone remodeling leading to osteolysis. We have recently shown that osteocytes are involved in MM-induced osteolysis through an increased cell death. Accordingly MM patients are characterized by a reduced number of viable osteocytes related to the presence of bone lesions. Proteasome inhibitors currently used in the treatment of MM are able to stimulate osteoblast formation but their potential effects on osteocyte death are not known and have been investigated in this study both in vitro and in vivo. Osteocytic MLO-Y4 cells or human pre-osteocytic HOB-01 cells were co-cultured for 48 hours in the presence or absence of the human myeloma cell lines (HMCLs) JJN3 or RPMI-8226 placed in a transwell insert. A significantly reduction of ostecyte viability was observed (median percent reduction of MLO-Y4 viability: -16% and -30%, respectively). The treatment for 12–24 hours with Bortezomib (BOR) (2nM) or other proteasome inhibitors such as MG262 (10nM) or MG132 (100nM) significantly blunted MLO-Y4 and HOB-01 cell death. Similarly, Dexamethasone (DEX)-induced MLO-Y4 apoptosis, obtained at pharmacological doses (10−4−10−5 M), was significantly reduced by the treatment with proteasome inhibitors. To translate our in vitro data into a clinical perspective we performed a retrospective histological evaluation on bone biopsies of a cohort of 40 newly diagnosis MM patients (24 male and 16 female, median age: 68 years) 34 of them with symptomatic MM and 6 with smoldering MM (SMM). The 58% of patients with symptomatic MM have evidence of osteolytic lesions at the X-rays survey. Bone biopsies were obtained in both symptomatic MM and SMM at diagnosis and after an average time of 12 months of treatment or observation, respectively. The 68% of patients with symptomatic MM were treated with a BOR-based regimen while 42% do not. Moreover the 58% of MM patients received DEX and the 59% Thalidomide (TAL). Zoledronic acid (ZOL) was infused monthly in the 60% of MM patients. Osteocyte viability was evaluated in a total of 500 lacunae per histological sections, corresponds to the total number of osteocyte lacunae in the bone biopsies. The number of viable osteocytes and the number of degenerated or apoptotic osteocytes and empty lacunae have been evaluated. In patients with SMM no significant change was observed in the number of viable osteocytes in the two histological evaluations carried out (median percent change: +1.2, p=0.68, NS). In symptomatic MM patients the mean percent change of the osteocyte viability was not correlated with the response rate to treatment (R2 0.01, p=NS). A significant increase of the number of viable osteocytes was demonstrated in MM patients treated with BOR-based regimen as compared to those treated without BOR (% median increase of osteocyte viability: +6% vs. +1.30%, Mann-Whitney test: p=0.017). Patients treated with BOR alone showed the highest increase of osteocyte viability that was statistical significant in comparison with that observed either in patients treated without BOR (+11.6% vs. +1.3%, p=0.0019) or in those treated with BOR plus DEX (+11.6% vs. +4.4%, p=0.01). On the contrary, no significant difference was observed in patients treated with TAL than in those treated without TAL (p= 0.7, NS) as well as patients treated with ZOL compared to those untreated showed no significant difference in the number of viable osteocytes (p=0.18, NS). To confirm the role of the different drug treatment on the osteocyte viability we perform a multiple regression non-parametric analysis showing that BOR had a significant positive impact on osteocyte viability (p=0.042) whereas ZOL and TAL have not (p>0.2,NS) and it counterbalanced the negative effect of DEX treatment (p=0.035). In conclusion our in vitro and in vivo data suggest the proteasome inhibitors block osteocyte death induced by MM cells could have a positive impact on bone integrity in MM patients. Disclosures: No relevant conflicts of interest to declare.

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