Ex Vivo Anti-Tumor Activity of Rosiglitazone on Multiple Myeloma Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5052-5052 ◽  
Author(s):  
Haiwen Huang ◽  
De Pei Wu ◽  
Anskar Y.H. Leung ◽  
Raymond Liang ◽  
Albert K.W. Lie
Keyword(s):  
Cell Proliferation ◽  
Caspase 3 ◽  
Hormone Receptors ◽  
Ex Vivo ◽  
Survivin Expression ◽  
Myeloma Cell ◽  
Dependent Manner ◽  
Novel Therapy ◽  
Apoptosis Protein ◽  
M Phase

Abstract Peroxisome proliferation activated receptor-g (PPAR-g) belongs to the family of nuclear hormone receptors (NHRs), it is normally expressed in adipocytes, adrenal gland, spleen and liver. Recently it was reported that PPAR-g can also be found in tumor tissues. Activation of PPAR-g by its ligands has potential anti-neoplastic effects in a variety of human malignancies, including leukemia through inhibition of cell proliferation, induction of apoptosis and terminal differentiation. The ligands of PPAR-g may represent a promising, novel therapeutic approach for certain human malignancies. The thiazolidinedione (TZD) class drug rosiglitazone (RGZ), one of synthetic ligands of PPAR-g, is currently used for the treatment of type 2 diabetes. In this study, we cultured myeloma cell line U266 with different concentration of rosiglitazone, as well as combined with dexamethasone. Cell proliferation was measured by [3H] thymidine incorporation after 48h incubation. Rosiglitazone was found to generate inhibition of cell proliferation on U266 cells in a dose-dependent manner. Cell cycle analysis by flow cytometry showed that rosiglitazone can arrested U266 cells in G0/G1 phase and the G2/M phase cells were significantly decreased compared to controls. We also studied the effect of rosiglitazone on expression of different anti-apoptosis protein FLIP and survivin by RT-PCR, the result revealed that rosiglitazone can also decrease the FLIP and survivin expression. Furthermore, exposure to rosiglitazone can induce the decreased caspase-3 activity in U266 cells, which was associated with apoptosis induction. When rosiglitazone was combined with dexamethasone, the data demonstrated that cell growth inhibition and apoptosis they exerted was much greater than they were used alone, the decreased expression of FLIP and survivin and decreased caspase-3 activity were also greater than when rosiglitazone was used alone. Based on these findings, we suppose that rosiglitazone alone and in combination with dexamethasone holds promise as novel therapy for myeloma.

Inhibition of Human Plasmacytoma Cell Growth by a Novel JAK Kinase Inhibitor.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 644-644
Author(s):  
Renate Burger ◽  
Steven Legouill ◽  
Yu-Tzu Tai ◽  
Reshma Shringarpure ◽  
Klaus Podar ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Cell Lines ◽  
Hormone Receptors ◽  
Critical Role ◽  
Myeloma Cell ◽  
Thymidine Uptake ◽  
Dependent Manner ◽  
Jak Kinase ◽  
Dose Dependent

Abstract Novel strategies in cancer therapy aim at inhibiting distinct signal transduction pathways that are aberrantly activated in malignant cells. Protein tyrosine kinases of the JAK family are associated with a number of cytokine and cytokine-like hormone receptors and regulate important cellular functions such as proliferation, survival, and differentiation. Constitutive or enhanced JAK activation has been implicated in neoplastic transformation and abnormal cell proliferation in various hematological malignancies. In multiple myeloma (MM), JAK kinases play a critical role because of their association with cytokine receptors of the IL-6/gp130 family. A novel small-molecule inhibitor was developed that shows a 100 to 1,000-fold selectivity for JAK1, JAK2, JAK3, and TYK2 relative to other kinases including Abl, Aurora, c-Raf, FGFR3, GSK3b, IGF-1R, Lck, PDGFRa, PKBb, and Zap-70. Growth of MM cell lines and primary patient cells was inhibited by this compound in a dose-dependent manner. The IL-6 dependent cell line INA-6 and derived sublines were sensitive to the drug, with IC50’s of less than 1 mM, in [3H]-thymidine uptake and a colorimetric, tetrazolium compound (MTS) based assay (CellTiter 96® Aqueous One Solution Cell Proliferation Assay, Promega, Madison, WI). Importantly, INA-6 and patient tumor cell growth was also inhibited in the presence of bone marrow stromal cells, which by themselves remained largely unaffected. Growth suppression of INA-6 correlated with a significant and dose-dependent increase in the percentage of apoptotic cells, as evaluated by Apo2.7 staining after 48 hours of drug treatment. In addition, the compound blocked IL-6 induced phosphorylation of STAT3, a direct downstream target of JAK kinases and important transcription factor triggering anti-apoptotic pathways. In other myeloma cell lines, the drug overcame the protective effect of gp130 cytokines on dexamethasone induced apoptosis. In MM1.S cells, it completely blocked IL-6 induced phosphorylation of SHP-2 and AKT, both known to mediate the protective effects of IL-6. In contrast, AKT phosphorylation induced by IGF-1 remained unchanged, demonstrating selectivity of the compound. These studies show that disruption of JAK kinase activity and downstream signaling pathways inhibits myeloma cell growth and survival as well as circumvents drug resistance, thereby providing the conceptual basis for the use of JAK kinase inhibitors as a novel therapeutic approach in MM.

Survivin Inhibition of p34Cdc2 Via Protection of Wee1 Correlates with Survival.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3352-3352
Author(s):  
Javier Rivera Guzman ◽  
Seiji Fukuda ◽  
Louis Pelus
Keyword(s):  
Cell Cycle ◽  
Caspase 3 ◽  
Survivin Expression ◽  
Dominant Negative ◽  
Dependent Manner ◽  
Hematopoietic Stem ◽  
Protein Levels ◽  
Apoptosis Protein ◽  
Apoptotic Activity ◽  
Active Caspase

Abstract The inhibitor of apoptosis protein Survivin and p34Cdc2 (the cyclin-dependent kinase, Cdk1) are involved in cell cycle progression and apoptosis. Cdc2 and Survivin are tightly regulated in normal cells but deregulated in cancer. We have previously shown that Survivin regulates entry of hematopoietic stem cells into cell cycle. It has been established that Cdc2 phosphorylates Survivin at threonine 34 (T34), which is believed to be a stabilizing event necessary for normal Survivin function and anti-apoptotic activity. Activation of Cdc2 is required for its apoptotic activity and inhibition of the proapoptotic activity of Cdc2 can be achieved by phosphorylation at tyrosine 15 (Tyr15). Stable overexpression of a wild-type (wt) mouse Survivin-IRES-GFP construct in IL-3-dependent mouse BaF3 cells resulted in increased Tyr15 phosphorylation of Cdc2 and enhanced cell proliferation, while cells transduced with a threonine 34 to alanine (T34A) dominant negative (DN) Survivin construct showed reduced Cdc2 Tyr15 phosphorylation and accelerated apoptosis. Furthermore, when apoptosis was induced in stably transduced BaF3 cells by IL-3 withdrawal, Survivin expression and phospho-Tyr15 levels correlated with enhanced survival and decreased survival and low phospho-Tyr15 levels correlated with Survivin disruption by T34A-DN-Survivin. Since Survivin does not contain intrinsic kinase activity we sought to determine what kinase(s) could be involved in stabilization or increase in phosphoTyr-15-Cdc2 by Survivin. Since Survivin inhibits caspase 3 activity and the Cdc2-targeting kinase Wee1 is a degradation target of active caspase 3, we performed immunoblotting assays on Survivin wt and T34A-transduced BaF3 cells and showed that cells over-expressing wt Survivin contain 2-fold higher levels of Wee1 protein as compared to those expressing vector or DN-Survivin. In addition, cells overexpressing wt Survivin contain >2-fold higher intact PARP protein levels which is another target of active caspase 3, as compared to cells transduced with MIEG vector. In order to test whether mimicking wt Survivin inhibition of caspase 3 could lead to increased Cdc2-Tyr15 phosphorylation, we evaluated the specific caspase 3 inhibitor Ac-DEVD-CHO. Inhibition of caspase 3 in BaF3 cells produced an increase in Cdc2Tyr15 phosphorylation in a dose-dependent manner, with 25 mM giving >4-fold higher intact PARP and >6-fold higher phospho-Tyr15 protein levels. Taken together, these results suggest that the antiapoptotic effect of Survivin is mediated through inactivation of Cdc2 by phosphorylation on Tyr-15 as a consequence of protection of the Wee1 kinase from degradation by caspase 3.

scholarly journals Integrated analysis of potential pathways by which aloe-emodin induces the apoptosis of colon cancer cells

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dongxiao Jiang ◽  
Shufei Ding ◽  
Zhujun Mao ◽  
Liyan You ◽  
Yeping Ruan
Keyword(s):  
Colon Cancer ◽  
Cell Proliferation ◽  
Cancer Cells ◽  
Caspase 3 ◽  
Time Dependent ◽  
Integrated Analysis ◽  
Dependent Manner ◽  
Colon Cancer Cells ◽  
Dapi Staining ◽  
Aloe Emodin

Abstract Background Colon cancer is a malignant gastrointestinal tumour with high incidence, mortality and metastasis rates worldwide. Aloe-emodin is a monomer compound derived from hydroxyanthraquinone. Aloe-emodin produces a wide range of antitumour effects and is produced by rhubarb, aloe and other herbs. However, the mechanism by which aloe-emodin influences colon cancer is still unclear. We hope these findings will lead to the development of a new therapeutic strategy for the treatment of colon cancer in the clinic. Methods We identified the overlapping targets of aloe-emodin and colon cancer and performed protein–protein interaction (PPI), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. In addition, we selected apoptosis pathways for experimental verification with cell viability, cell proliferation, caspase-3 activity, DAPI staining, cell cycle and western blotting analyses to evaluate the apoptotic effect of aloe-emodin on colon cancer cells. Results The MTT assay and cell colony formation assay showed that aloe-emodin inhibited cell proliferation. DAPI staining confirmed that aloe-emodin induced apoptosis. Aloe-emodin upregulated the protein level of Bax and decreased the expression of Bcl-2, which activates caspase-3 and caspase-9. Furthermore, the protein expression level of cytochrome C increased in a time-dependent manner in the cytoplasm but decreased in a time-dependent manner in the mitochondria. Conclusion These results indicate that aloe-emodin may induce the apoptosis of human colon cancer cells through mitochondria-related pathways.

Effect of Metformin Intervention on Pancreatic β-Cell Apoptosis

2022 ◽  
Vol 12 (4) ◽  
pp. 873-877
Author(s):  
Dongqian Xie ◽  
Zhicheng Gao ◽  
Mei Liu ◽  
Defeng Wang
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Cell Apoptosis ◽  
Dependent Manner ◽  
Cycle Arrest ◽  
High Glucose Condition ◽  
M Phase ◽  
Signaling Activation

Metformin is shown to have hypoglycemic effects. However, the relationship between metformin’s intervention in FFA-induced endoplasmic reticulum stress-mediated insulin resistance (IR) and insulin β-cell apoptosis under high-glucose condition remains unclear. Our study intends to assess their relationship. Human pancreatic β-cells were treated with metformin and cell proliferation and IR were detected by MTT assay along with detection of Wnt/β-catenin signaling by RT-PCR, cell cycle and apoptosis by flow cytometry. Metformin inhibited β cell proliferation which was mediated by FFA-induced endoplasmic reticulum stress in a time-dependent and dose-dependent manner as well as induced cell cycle arrest at G2/M phase. In addition, metformin inhibited β-catenin signaling activation and decreased the expression of c-myc, Dvl-2, survivin, Dvl-3, GSK-3β (p-ser9) and promoted GSK-3 (p-tyr216) and Axin-2 expression. In conclusion, metformin inhibits Wnt/β-catenin signaling and promotes FFA to induce endoplasmic reticulum stress, thereby mediating pancreatic β-cells behaviors.

MK886 Induced Apoptosis in HL-60 Cells Via Inhibition mPGES-1 Expression and Down-Regulation Prostaglandin E2 Synthesize.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4824-4824
Author(s):  
Yiqing Li ◽  
Songmei Yin ◽  
Shuangfeng Xie ◽  
Danian Nie ◽  
Liping Ma ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Expression ◽  
Prostaglandin E2 ◽  
Cell Line ◽  
Caspase 3 ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Dependent Manner ◽  
Pge2 Synthesis ◽  
Dose Dependent

Abstract Abstract 4824 Recent studies have shown that prostaglandin E2 (PGE2) may play a key role in the tumorigenesis and tumor development. Membrane-bound prostaglandin E2 synthase-1 (mPGES-1), an inducible enzyme that acts downstream of cyclooxygenase (COX) and specifically catalyzes the conversion of prostaglandin H2 (PGH2) to PGE2, was over-expression in a variety of solid tumor cells and tissues such as nonsmall-cell lung cancer, colon carcinoma, gastric carcinoma and breast cancer. MK886, a small molecular inhibitor, is a reasonable potency as an inhibitor of mPGES-1 in vitro experiment. In this study, we examined effects of MK886 on expression of mPGES-1 and PGE2 synthesis in human acute myeloid leukemia cell line (HL-60), observed cell proliferation and apoptosis after 24-h treatment with MK886, and tried to explore the possible mechanisms by checking some protein belong AKT cell singling pathway such as P-AKT, Bax and Bcl-2. We found that the expression levels of mPGES-1 mRNA and protein were higher in HL-60 cells than in normal mononuclearcells (MNC). MK886 inhibited mPGES-1 mRNA and protein expression and reduced PGE2 secretion in HL-60 cells in a dose-dependent manner. The cell proliferation was inhibited and the IC50 was 132.16μmol/L. With the increase of MK886 concentration, the cell apoptosis rate assayed by flow cytometry increased and the apparent apoptotic bodies increased when staining by Hoechst 33258. After treated with MK886 for 24h, protein was extracted and assayed by western blot. The results showed that the expression levels of P-AKT, Bcl-2 and c-myc decreased while the Bax protein expression increased in a dose-dependent manner. The caspase-3 activity, determined by colorimetric detection, also increased dose-dependently. These results indicated that mPGES-1 over-expressed in leukemia cell line HL-60, MK886 could induce apoptosis in HL-60 cells via reducing mPGES-1 expression and PGE2 synthesis dose-dependently, thereby regulate the AKT pathway including Bcl-2 family and the activity of caspase-3. It suggested that mPGES-1 inhibitor might emerge as an important therapeutic tool for leukemia treatment. Disclosures: No relevant conflicts of interest to declare.

MAGE-C1/CT7 Inhibition Increases Myeloma Cell Line Sensitivity to Bortezomib-Induced Apoptosis: New Target for Myeloma Therapy?

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1908-1908
Author(s):  
Fabricio de Carvalho ◽  
Erico T. Costa ◽  
Anamaria A. Camargo ◽  
Juliana C. Gregorio ◽  
Cibele Masotti ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Line ◽  
Cell Cycle Regulation ◽  
Myeloma Cell ◽  
Myeloma Cell Line ◽  
Empty Vector ◽  
M Phase ◽  
Induced Apoptosis ◽  
Cycle Regulation

Abstract Abstract 1908 Introduction: MAGE-C1/CT7 encodes for a cancer/testis antigen (CTA) frequently expressed in multiple myeloma (MM) that may be a potential target for immunotherapy in this still incurable disease. The expression of this CTA is restricted to malignant plasma cells and a positive correlation between MAGEC1/CT7 expression and advanced stage has been demonstrated for MM. It has been suggested that MAGE-C1/CT7 might play a pathogenic role in MM; however, the exact function of this protein in the pathophysiology of MM is not yet understood. Objectives: (1) To clarify the role of MAGE-C1/CT7 in the control of cellular proliferation and cell cycle regulation in myeloma cell line SKO-007 and (2) to evaluate the impact of silencing MAGE-C1/CT7 on cells treated with bortezomib. Material and Methods: Short hairpin RNA (shRNA) specific for MAGE-C1/CT7 was inserted in the pRETROSUPER(pRS) retroviral vector. The pRS-shRNA-MAGE-C1/CT7 was co-transfected with pCL-amphotropic packing vector in 293T cells to produce virus particles. Sko-007 myeloma cell line was transduced for stable expression of shRNA-MAGE-C1/CT7. Downregulation of MAGE-C1/CT7 was confirmed by real time PCR (RQ-PCR) and western blot. Functional studies included cell proliferation, cell cycle analysis using propidium iodide, and analysis of apoptosis using annexin V staining. Results: SKO-007 MM cell line was transduced for stable expression of shRNA-MAGE-C1/CT7. SKO-007 cells were divided into three derivatives: empty vector (pRS) and ineffective shRNA (antisense strand deleted – GC bases) [both used as controls for all the experiments] and inhibited (shMAGE-C1/CT7). MAGE-C1/CT7 mRNA expression was ∼5 times lower in inhibited cell line than control cells by RQ-PCR. Western blot showed 70–80% decrease in MAGE-C1/CT7 protein expression in inhibited cells when compared with controls. Functional assays did not indicate a difference in cell proliferation and DNA synthesis when inhibited cells were compared with controls. We used empty vector, ineffective shRNA and inhibited cells to determine whether inhibition of MAGE-C1/CT7 was associated with cell cycle dysregulation. We detected differences between inhibited cells and both controls regarding the proportion of myeloma cells in the G2/M phase (p<0.05). When inhibited cells and controls were treated with 10 nM bortezomib for 48h, inhibited cells showed a 48% reduction of cells in the G2/M phase but control cells have 11% (empty vector) and 10% (ineffective shRNA) of reduction (p<0.05). Inhibited cells treated with 15 nM bortezomib showed an increased percentage of apoptotic cells in comparison with bortezomib treated controls (p<0.01) [Figure]. Conclusions: MAGE-C1/CT7 antigen inhibition did not change cell proliferation and DNA synthesis in SKO-007 cells. However, we found that MAGE-C1/CT7 plays in cell cycle regulation, protecting SKO-007 cells against bortezomib-induced apoptosis. Therefore, MAGE-C1/CT7 silencing by shRNA could be a strategy for future therapies in MM, i.e. in combination with proteasome inhibitors. [Supported by CNPq and LICR] Disclosures: No relevant conflicts of interest to declare.

scholarly journals Bufalin Inhibits HCT116 Colon Cancer Cells and Its Orthotopic Xenograft Tumor in Mice Model through Genes Related to Apoptotic and PTEN/AKT Pathways

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jie Wang ◽  
Chao Chen ◽  
Shiying Wang ◽  
Yong Zhang ◽  
Peihao Yin ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Growth ◽  
Cell Apoptosis ◽  
Caspase 3 ◽  
Cultured Cells ◽  
Xenograft Model ◽  
Dependent Manner ◽  
Apoptotic Pathway ◽  
Orthotopic Tumor ◽  
Orthotopic Xenograft

Aims. To investigate the anticolorectal cancer (CRC) effects of Bufalin, a bioactive polyhydroxysteroid from Venenum Bufonis, using HCT116 human CRC cell and an established orthotopic xenograft model in mice, and to explore the mechanisms of action.Material and Methods. Cultured HCT116 cells or BALB/c mice with orthotopic tumor were treated by Bufalin (positive control: 5-FU). Cell proliferation, apoptosis, and cycling were determined by MTT, Annexin V/PI staining, and flow cytometry, respectively. In mice, tumor inhibition rate and animal survival were calculated. The expressions of PTEN/phosphate-PTEN, AKT/phosphate-AKT, Bad, Bcl-xl, Bax, or Caspase-3 in cells and/or tumors were determined by Western blot or immunohistochemical staining.Results. Bufalin significantly inhibited cell proliferation and induced cell apoptosis and cycle arrest in a dose/time-dependent manner. In the animal model, Bufalin treatment resulted in significant inhibition of tumor growth and prolonged survival. In the Bufalin-treated cultured cells and/or xenograft tumors, the expressions of PTEN, Bad, Bax, and Caspase-3 were significantly increased, while p-AKT and Bcl-xL significantly decreased.Conclusions. Our results indicate that Bufalin inhibit cell proliferation and orthotopic tumor growth by inducing cell apoptosis through the intrinsic apoptotic pathway, which is of pivotal significance in the identification of an anticancer drug that may synergize with Bufalin.

scholarly journals Knockout of caspase-7 gene improves the expression of recombinant protein in CHO cell line through the cell cycle arrest in G2/M phase

2022 ◽  
Vol 55 (1) ◽  
Author(s):  
Fatemeh Safari ◽  
Bahman Akbari
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Enzymatic Activity ◽  
Cell Cycle Arrest ◽  
Cell Line ◽  
Caspase 3 ◽  
Cho Cell ◽  
Cycle Arrest ◽  
M Phase ◽  
Caspase 7

Abstract Background Chinese hamster ovary cell line has been used routinely as a bioproduction factory of numerous biopharmaceuticals. So far, various engineering strategies have been recruited to improve the production efficiency of this cell line such as apoptosis engineering. Previously, it is reported that the caspase-7 deficiency in CHO cells reduces the cell proliferation rate. But the effect of this reduction on the CHO cell productivity remained unclear. Hence, in the study at hand the effect of caspase-7 deficiency was assessed on the cell growth, viability and protein expression. In addition, the enzymatic activity of caspase-3 was investigated in the absence of caspase-7. Results Findings showed that in the absence of caspase-7, both cell growth and cell viability were decreased. Cell cycle analysis illustrated that the CHO knockout (CHO-KO) cells experienced a cell cycle arrest in G2/M phase. This cell cycle arrest resulted in a 1.7-fold increase in the expression of luciferase in CHO-KO cells compared to parenteral cells. Furthermore, in the apoptotic situation the enzymatic activity of caspase-3 in CHO-KO cells was approximately 3 times more than CHO-K1 cells. Conclusions These findings represented that; however, caspase-7 deficiency reduces the cell proliferation rate but the resulted cell cycle arrest leads to the enhancement of recombinant protein expression. Moreover, increasing in the caspase-3 enzymatic activity compensates the absence of caspase-7 in the caspase cascade of apoptosis.

scholarly journals Inhibition of ATR-Chk1 signaling blocks DNA double-strand-break repair and induces cytoplasmic vacuolization in metastatic osteosarcoma

2020 ◽  
Vol 12 ◽  
pp. 175883592095690 ◽  
Author(s):  
Xiaoyang Li ◽  
Dylan C. Dean ◽  
Gregory M. Cote ◽  
Lee Zou ◽  
Francis J. Hornicek ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Dna Damage ◽  
Therapeutic Target ◽  
Ex Vivo ◽  
Dna Damage Repair ◽  
Parp Cleavage ◽  
Dependent Manner ◽  
Cytoplasmic Vacuolization ◽  
Damage Repair ◽  
Metastatic Osteosarcoma

Background: Ataxia-telangiectasia and Rad3 related protein kinase (ATR) is an essential regulator of the DNA damage response in various cancers; however, its expression and roles in osteosarcoma are unclear. We therefore chose to evaluate the significance and mechanism of ATR in metastatic osteosarcoma, as well as its potential to be a therapeutic target. Methods: The osteosarcoma tissue microarrays constructed from 70 patient specimens underwent immunohistochemistry to quantify ATR and activated phospho-ATR (pATR) expression and their correlation with clinical outcomes. ATR sublocalization within the metastatic osteosarcoma cells was confirmed by immunofluorescence assay. Cell proliferation, apoptosis, and migration were evaluated following treatment with ATR siRNA or the selective inhibitor Berzosertib. Antitumor effects were determined with ex vivo three-dimensional (3D) culture models, and the impacts on the DNA damage repair pathways were measured with Western blotting. Results: Elevated ATR and activated pATR expression correlated with shorter patient survival and less necrosis following neoadjuvant chemotherapy. Intranuclear sublocalization of ATR and pATR suggested a mechanism related to DNA replication. ATR knockdown with siRNA or inhibition with Berzosertib suppressed cell proliferation in a time- and dose-dependent manner and induced apoptosis. In addition, ATR inhibition decreased Chk1 phosphorylation while increasing γH2AX expression and PARP cleavage, consistent with the interference of DNA damage repair. The ATR inhibitor Berzosertib also produced the characteristic cytoplasmic vacuolization preceding cell death, and suppressed ex vivo 3D spheroid formation and cell motility. Conclusion: The faithful dependence of cells on ATR signaling for survival and progression makes it an emerging therapeutic target in metastatic osteosarcoma.

APCK110, a Novel and Potent Inhibitor of c-Kit, Blocks Phosphorylation of AKT and STAT3, Induces Apoptosis, and Inhibits Proliferation of Acute Myeloid Leukemia (AML) Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 153-153 ◽  
Author(s):  
Stefan Faderl ◽  
William Bornmann ◽  
David Maxwell ◽  
Ashutosh Pal ◽  
Zheng-Hong Peng ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Line ◽  
Cell Lines ◽  
Caspase 3 ◽  
Potent Inhibitor ◽  
Antiproliferative Effect ◽  
Parp Cleavage ◽  
Dependent Manner ◽  
Western Immunoblotting ◽  
Inhibition Of Proliferation

Abstract Tight control of protein tyrosine kinase (TK) activity is crucial for the regulation and maintenance of vital cellular functions such as proliferation, differentiation, and apoptosis. c-KIT is a TK and transmembrane receptor for stem cell factor (SCF). Binding of SCF to c-KIT results in activation of marrow precursors and other blood cells. Activating mutations of c-KIT associated with amino acid Asp-816 (D816) have been identified in leukemic cells of patients with AML and are thought to play an important pathophysiologic role in leukemogenesis. Identification of activating c-KIT mutations and development of novel compounds targeting these mutations may therefore be of therapeutic benefit in AML. Based on the 3-dimensional structure of c-KIT we have generated a number of compounds with activity against c-KIT mutated cells. Here we present initial results of the activity and mechanism of action of the novel c-KIT inhibitor APCK110 in AML cell lines and primary samples from patients with AML. Using an MTT assay, we first studied the antiproliferative effect of APCK110 in the AML cell lines OCI/AML3 and the SCF-responsive cell line OCIM2. Cells were incubated for 72 hours without or with APCK110 at concentrations of 50, 100, 250, and 500 nM, then harvested and their metabolic activity and viability determined as optical density. Next we determined expression of phospho-AKT and -STAT3 in the mastocytosis cell line HMC1.1 and phospho-c-KIT in the AML cell line OCI/AML3 by Western Immunoblotting. We further analyzed induction of caspase 3 and PARP cleavage in OCI/AML3 cells at APCK110 concentrations of 50, 100, 250, and 500 nM using Western Immunoblotting. To demonstrate the effect of APCK110 on primary AML cells, we incubated diagnostic marrow cells from 3 patients with AML with increasing concentrations of APCK110 and used the blast colony assay to measure inhibition of proliferation. We then compared the antiproliferative effect of APCK110 with that of dasatinib and imatinib in OCI/AML3 cells. We show that 1) APCK110 strongly inhibits proliferation of AML cells with 80% inhibition at 500 nM; 2) similar to cell lines, APCK110 also inhibits AML colony growth of primary samples in a dose-dependent manner of up to 80% at 500 nM concentration; 3) APCK110 blocks activation of phospho-AKT, phospho-STAT3, and phospho-c-KIT; 4) APCK110 induces apoptosis by cleavage of caspase 3 and PARP; and 5) APCK110 demonstrates more potent inhibition (up to 100% at 500 nM) of AML cell proliferation than dasatinib (60% at 500 nM) and dasatinib (none at 500 nM). In summary, APCK110 is a novel and potent inhibitor of mutated c-KIT that inhibits AML cell proliferation, blocks activation of intracellular signaling molecules, and induces caspase-dependent apoptosis. Further development of APCK110 for clinical trials of patients with AML should be pursued.

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