Pim Kinases Mediate Viability Signals Downstream of the Tyrosine Kinase Oncogenes BCR-ABL and FLT3-ITD.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 557-557
Author(s):  
Martin Sattler ◽  
Emily Babendreier ◽  
Stephanie C. Chu ◽  
Jessica L. Gramlich ◽  
Klaus Podar ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cell Growth ◽  
Cell Lines ◽  
Tyrosine Kinases ◽  
Molecular Mechanisms ◽  
Biological Effects ◽  
Hematopoietic Cells ◽  
Target Cells ◽  
Therapeutic Effects ◽  
Pim Kinases

Abstract Pim1 and Pim2 belong to a family of serine/threonine kinases that are overexpressed in many leukemias. Pim1 has previously been shown to cooperate with the v-myc oncogene to transform hematopoietic cells with murine transforming viruses and overexpression of Pim2 has been shown to induce growth factor independence in a factor dependent murine BaF3 cell line. Protein expression of both Pim1 and Pim2 is low or absent in non-transformed hematopoietic cells but was found to be rapidly increased upon transformation by BCR-ABL or FLT3 with an internal tandem duplication (ITD). The exact contribution of the Pim kinases to transformation in these cells is unknown. BaF3 cell lines were created that stably expressed either BCR-ABL or FLT3-ITD tyrosine kinases, and in which either Pim1 or Pim2 could be induced with doxycycline. Treatment of BCR-ABL or FLT3-ITD expressing cells with small molecule kinase inhibitors specific for either ABL or FLT3 led to inhibition of cell growth, increased apoptosis, and downregulation of Pim expression as expected. However, if Pim2, and to a lesser extent, Pim1 expression was maintained by doxycycline, there was a substantial increase in both viability and cell growth. The molecular mechanisms by which Pim proteins exhibit their effects on target cells are not known. Using parental growth factor dependent BaF3 cell lines with doxycycline inducible Pim1 and Pim2, we show that expression of either of the Pim proteins is sufficient, by itself, to reduce apoptosis and induce modest cell growth. The effects of Pim overexpression on several pathways known to be associated with viability were studied. We found that while Pim over-expression does not activate Akt, it does result in the phosphorylation of a known Akt target, GSK-3β, a regulator of cell cycle progression by targeting the stability of cyclin D proteins. This suggests that Pim proteins may mediate their biological effects through regulation of components in the phosphatidylinositol-3′ kinase signaling cascade, independent of Akt activation. These results further suggest that upregulation of Pim kinases significantly contributes to transformation. Inhibition of Pim kinases could have beneficial therapeutic effects in leukemias.

scholarly journals Structural basis for activation of trimeric Gi proteins by multiple growth factor receptors via GIV/Girdin

2014 ◽  
Vol 25 (22) ◽  
pp. 3654-3671 ◽  
Author(s):  
Changsheng Lin ◽  
Jason Ear ◽  
Krishna Midde ◽  
Inmaculada Lopez-Sanchez ◽  
Nicolas Aznar ◽  
...  
Keyword(s):  
Growth Factor ◽  
G Proteins ◽  
Protein Interaction ◽  
Cross Talk ◽  
Tyrosine Kinases ◽  
Molecular Mechanisms ◽  
Growth Factor Receptors ◽  
Structural Basis ◽  
Nucleotide Exchange ◽  
Protein Protein Interaction

A long-standing issue in the field of signal transduction is to understand the cross-talk between receptor tyrosine kinases (RTKs) and heterotrimeric G proteins, two major and distinct signaling hubs that control eukaryotic cell behavior. Although stimulation of many RTKs leads to activation of trimeric G proteins, the molecular mechanisms behind this phenomenon remain elusive. We discovered a unifying mechanism that allows GIV/Girdin, a bona fide metastasis-related protein and a guanine-nucleotide exchange factor (GEF) for Gαi, to serve as a direct platform for multiple RTKs to activate Gαi proteins. Using a combination of homology modeling, protein–protein interaction, and kinase assays, we demonstrate that a stretch of ∼110 amino acids within GIV C-terminus displays structural plasticity that allows folding into a SH2-like domain in the presence of phosphotyrosine ligands. Using protein–protein interaction assays, we demonstrated that both SH2 and GEF domains of GIV are required for the formation of a ligand-activated ternary complex between GIV, Gαi, and growth factor receptors and for activation of Gαi after growth factor stimulation. Expression of a SH2-deficient GIV mutant (Arg 1745→Leu) that cannot bind RTKs impaired all previously demonstrated functions of GIV—Akt enhancement, actin remodeling, and cell migration. The mechanistic and structural insights gained here shed light on the long-standing questions surrounding RTK/G protein cross-talk, set a novel paradigm, and characterize a unique pharmacological target for uncoupling GIV-dependent signaling downstream of multiple oncogenic RTKs.

An epidermal growth factor receptor/ret chimera generates mitogenic and transforming signals: evidence for a ret-specific signaling pathway

1994 ◽  
Vol 14 (1) ◽  
pp. 663-675
Author(s):  
M Santoro ◽  
W T Wong ◽  
P Aroca ◽  
E Santos ◽  
B Matoskova ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinases ◽  
Mammalian Cells ◽  
Egf Receptor ◽  
Biological Effects ◽  
Ectopic Expression ◽  
Growth Factor Receptor ◽  
Dependent Signal ◽  
Epidermal Growth

A chimeric expression vector which encoded for a molecule encompassing the extracellular domain of the epidermal growth factor (EGF) receptor (EGFR) and the intracellular domain of the ret kinase (EGFR/ret chimera) was generated. Upon ectopic expression in mammalian cells, the EGFR/ret chimera was correctly synthesized and transported to the cell surface, where it was shown capable of binding EGF and transducing an EGF-dependent signal intracellularly. Thus, the EGFR/ret chimera allows us to study the biological effects and biochemical activities of the ret kinase under controlled conditions of activation. Comparative analysis of the growth-promoting activity of the EGFR/ret chimera expressed in fibroblastic or hematopoietic cells revealed a biological phenotype clearly distinguishable from that of the EGFR, indicating that the two kinases couple with mitogenic pathways which are different to some extent. Analysis of biochemical pathways implicated in the transduction of mitogenic signals also evidenced significant differences between the ret kinase and other receptor tyrosine kinases. Thus, the sum of our results indicates the existence of a ret-specific pathway of mitogenic signaling.

scholarly journals MicroRNA-138 Inhibits Cell Growth, Invasion, and EMT of Non-Small Cell Lung Cancer via SOX4/p53 Feedback Loop

2018 ◽  
Vol 26 (3) ◽  
pp. 385-400 ◽  
Author(s):  
Dandan Li ◽  
Changjun He ◽  
Junfeng Wang ◽  
Yanbo Wang ◽  
Jianlong Bu ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cell Growth ◽  
Small Cell Lung Cancer ◽  
Cell Lines ◽  
Cell Lung Cancer ◽  
Feedback Loop ◽  
Molecular Mechanisms ◽  
Small Cell ◽  
Luciferase Reporter ◽  
Small Cell Lung

Many studies have shown that downregulation of miR-138 occurs in a variety of cancers including non-small cell lung cancer (NSCLC). However, the precise mechanisms of miR-138 in NSCLC have not been well clarified. In this study, we investigated the biological functions and molecular mechanisms of miR-138 in NSCLC cell lines, discussing whether it could turn out to be a therapeutic biomarker of NSCLC in the future. In our study, we found that miR-138 is downregulated in NSCLC tissues and cell lines. Moreover, the low level of miR-138 was associated with increased expression of SOX4 in NSCLC tissues and cell lines. Upregulation of miR-138 significantly inhibited proliferation of NSCLC cells. In addition, invasion and EMT of NSCLC cells were suppressed by overexpression of miR-138. However, downregulation of miR-138 promoted cell growth and metastasis of NSCLC cells. Bioinformatics analysis predicted that SOX4 was a potential target gene of miR-138. Next, luciferase reporter assay confirmed that miR-138 could directly target SOX4. Consistent with the effect of miR-138, downregulation of SOX4 by siRNA inhibited proliferation, invasion, and EMT of NSCLC cells. Overexpression of SOX4 in NSCLC cells partially reversed the effect of miR-138 mimic. In addition, decreased SOX4 expression could increase the level of miR-138 via upregulation of p53. Introduction of miR-138 dramatically inhibited growth, invasion, and EMT of NSCLC cells through a SOX4/p53 feedback loop.

scholarly journals An inhibitor of the EGF receptor family blocks myeloma cell growth factor activity of HB-EGF and potentiates dexamethasone or anti–IL-6 antibody-induced apoptosis

Blood ◽  
2004 ◽  
Vol 103 (5) ◽  
pp. 1829-1837 ◽  
Author(s):  
Karène Mahtouk ◽  
Michel Jourdan ◽  
John De Vos ◽  
Catherine Hertogh ◽  
Geneviève Fiol ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Growth Factor ◽  
Cell Growth ◽  
Cell Lines ◽  
Stromal Cells ◽  
Egf Receptor ◽  
Myeloma Cell ◽  
Factor Activity ◽  
Myeloma Cells ◽  
Induced Apoptosis

Abstract We previously found that some myeloma cell lines express the heparin-binding epidermal growth factor–like growth factor (HB-EGF) gene. As the proteoglycan syndecan-1 is an HB-EGF coreceptor as well as a hallmark of plasma cell differentiation and a marker of myeloma cells, we studied the role of HB-EGF on myeloma cell growth. The HB-EGF gene was expressed by bone marrow mononuclear cells in 8 of 8 patients with myeloma, particularly by monocytes and stromal cells, but not by purified primary myeloma cells. Six of 9 myeloma cell lines and 9 of 9 purified primary myeloma cells expressed ErbB1 or ErbB4 genes coding for HB-EGF receptor. In the presence of a low interleukin-6 (IL-6) concentration, HB-EGF stimulated the proliferation of the 6 ErbB1+ or ErbB4+ cell lines, through the phosphatidylinositol 3-kinase/AKT (PI-3K/AKT) pathway. A pan-ErbB inhibitor blocked the myeloma cell growth factor activity and the signaling induced by HB-EGF. This inhibitor induced apoptosis of patients'myeloma cells cultured with their tumor environment. It also increased patients' myeloma cell apoptosis induced by an anti–IL-6 antibody or dexamethasone. The ErbB inhibitor had no effect on the interaction between multiple myeloma cells and stromal cells. It was not toxic for nonmyeloma cells present in patients' bone marrow cultures or for the growth of hematopoietic progenitors. Altogether, these data identify ErbB receptors as putative therapeutic targets in multiple myeloma.

Anandamide, a Natural Ligand for the Peripheral Cannabinoid Receptor Is a Novel Synergistic Growth Factor for Hematopoietic Cells

Blood ◽  
1997 ◽  
Vol 90 (4) ◽  
pp. 1448-1457 ◽  
Author(s):  
Peter Valk ◽  
Sandra Verbakel ◽  
Yolanda Vankan ◽  
Samantha Hol ◽  
Shanta Mancham ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cell Lines ◽  
Cannabinoid Receptor ◽  
Calf Serum ◽  
Hematopoietic Cells ◽  
Mouse Bone Marrow ◽  
Colony Stimulating Factor ◽  
Rnase Protection ◽  
Stimulating Factor ◽  
Marrow Cells

Abstract We recently demonstrated that the gene encoding the peripheral cannabinoid receptor (Cb2) may be a proto-oncogene involved in murine myeloid leukemias. We show here that Cb2 may have a role in hematopoietic development. RNAse protection analysis showed that Cb2 is normally expressed in spleen and thymus. Cb2 mRNA is also expressed in 45 of 51 cell lines of distinct hematopoietic lineages, ie, myeloid, macrophage, mast, B-lymphoid, T-lymphoid, and erythroid cells. The effect of the fatty acid anandamide, an endogenous ligand for cannabinoid receptors, on primary murine marrow cells and hematopoietic growth factor (HGF )-dependent cell lines was then investigated. In vitro colony cultures of normal mouse bone marrow cells showed anandamide to potentiate interleukin-3 (IL-3)–induced colony growth markedly. Whereas HGFs alone stimulate proliferation of the various cell lines in serum-free culture only weakly, anandamide enhances the proliferative response of the cell lines to HGFs profoundly. This was apparent for responses induced by IL-3, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, and erythropoietin. Anandamide was already effective at concentrations as low as 0.1 to 0.3 μmol/L and plateau effects were reached at 0.3 to 3 μmol/L. The addition of anandamide as single growth factor had no effect. The costimulatory effect of anandamide was not evident when cells were cultured with fetal calf serum (FCS), suggesting that FCS contains anandamide or another ligand capable of activating the peripheral cannabinoid receptor. Other cannabinoid ligands did not enhance the proliferative responsiveness of hematopoietic cells to HGFs. Transfection experiments of Cb2 in myeloid 32D cells showed that anandamide specifically activates proliferation through activation of the peripheral cannabinoid receptor. Anandamide appears to be a novel and synergistic growth stimulator for hematopoietic cells.

scholarly journals Regulation of Cell Growth

1987 ◽  
Vol 80 (9) ◽  
pp. 591-593
Author(s):  
A J Barrett
Keyword(s):  
Stem Cells ◽  
Growth Factors ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Cell Growth ◽  
Cell Lines ◽  
Growth Regulation ◽  
Platelet Derived Growth Factor ◽  
Haemopoietic Stem Cells

At this meeting of the RSM's Section of Pathology, the regulation of haemopoietic stem cells and growth factors regulating various cell lines were described, and the role of oncogenes, platelet-derived growth factor and nerve growth factor in growth regulation was discussed.

scholarly journals Transcriptome of Two Canine Prostate Cancer Cells Treated With Toceranib Phosphate Reveals Distinct Antitumor Profiles Associated With the PDGFR Pathway

2020 ◽  
Vol 7 ◽  
Author(s):  
Priscila E. Kobayashi ◽  
Patrícia F. Lainetti ◽  
Antonio F. Leis-Filho ◽  
Flávia K. Delella ◽  
Marcio Carvalho ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Growth Factor ◽  
Protein Expression ◽  
Cell Line ◽  
Cell Lines ◽  
Protein Interactions ◽  
Tyrosine Kinases ◽  
Growth Factor Receptor ◽  
Dependent Manner ◽  
Upregulated Genes

Canine prostate cancer (PC) presents a poor antitumor response, usually late diagnosis and prognosis. Toceranib phosphate (TP) is a nonspecific inhibitor of receptor tyrosine kinases (RTKs), including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and c-KIT. This study aimed to evaluate VEGFR2, PDGFR-β, and c-KIT protein expression in two established canine PC cell lines (PC1 and PC2) and the transcriptome profile of the cells after treatment with TP. Immunofluorescence (IF) analysis revealed VEGFR2 and PDGFR-β protein expression and the absence of c-KIT protein expression in both cell lines. After TP treatment, only the viability of PC1 cells decreased in a dose-dependent manner. Transcriptome and enrichment analyses of treated PC1 cells revealed 181 upregulated genes, which were related to decreased angiogenesis and cell proliferation. In addition, we found upregulated PDGFR-A, PDGFR-β, and PDGF-D expression in PC1 cells, and the upregulation of PDGFR-β was also observed in treated PC1 cells by qPCR. PC2 cells had fewer protein-protein interactions (PPIs), with 18 upregulated and 22 downregulated genes; the upregulated genes were involved in the regulation of parallel pathways and mechanisms related to proliferation, which could be associated with the resistance observed after treatment. The canine PC1 cell line but not the PC2 cell line showed decreased viability after treatment with TP, although both cell lines expressed PDGFR and VEGFR receptors. Further studies could explain the mechanism of resistance in PC2 cells and provide a basis for personalized treatment for dogs with PC.

scholarly journals Platelet Factor 4 and Other CXC Chemokines Support the Survival of Normal Hematopoietic Cells and Reduce the Chemosensitivity of Cells to Cytotoxic Agents

Blood ◽  
1997 ◽  
Vol 89 (7) ◽  
pp. 2328-2335 ◽  
Author(s):  
Zhong Chao Han ◽  
Min Lu ◽  
Junmin Li ◽  
Mai Defard ◽  
Bernadette Boval ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Growth Factor ◽  
Cell Lines ◽  
Cancer Cell ◽  
Bone Marrow Cells ◽  
Hematopoietic Cells ◽  
Platelet Factor 4 ◽  
Cytotoxic Agents ◽  
Platelet Factor ◽  
Cd34 Cells

Abstract The effects of platelet factor 4 (PF4) on the viability and chemosensitivity of normal hematopoietic cells and cancer cell lines were studied to determine the mechanisms whereby PF4 functions as either an inhibitor or a protector and to evaluate its clinical significance. Two other chemokines, interleukin-8 (IL-8) and neutrophil-activating peptide-2 (NAP-2), were also studied in comparison to PF4. Using a tetrazolium salt assay for cell viability, we observed that PF4 at 1 to 50 μg/mL supported the viability of normal human bone marrow cells. Approximately 45% of cells cultured for 48 hours survived, whereas 80% or more survived in the presence of PF4 5 μg/mL. PF4 also supported the viability of CD34+ cord blood (CB) cells and protected them from apoptosis induced by transforming growth factor β1 (TGFβ1) and cytotoxic drugs. Pretreatment of CD34+ cells by PF4, but not by TGFβ1, caused an increase in the number of megakaryocyte colonies after these cells were replated in secondary cultures. Flow cytometry analysis showed that when CD34+ cells were preincubated with PF4 or TGFβ1 for 12 days in hematopoietic growth factor–rich medium, an increased number of remaining CD34+ cells was observed only for PF4-treated cells. Furthermore, PF4 significantly reduced the chemosensitivity of bone marrow cells, as shown by its ability to increase the 50% inhibition concentration (IC50) of several cytotoxic agents. Like PF4, IL-8 and NAP-2 at 0.1, 0.6, and 1 μg/mL supported the survival of myeloid progenitors, including colony-forming units granulocyte, erythroblast, monocyte, megakaryocyte (CFU-GEMM), CFU-megakaryocyte (CFU-MK), CFU–granulocyte/macrophage (CFU-GM), and burst-forming units–erythroblast (BFU-E), and reduced their sensitivity to the toxicity of etoposide (ETP). Protamine sulfate at 1 to 100 μg/mL showed no such activity of PF4. Interestingly, the three chemokines failed to affect significantly the viability and chemosensitivity of three leukemic and two other tumor cell lines. Based on these results, we conclude for the first time that PF4 and IL-8 and NAP-2 support the survival of normal hematopoietic precursors and protect them from the toxicity of chemotherapeutic agents. Because such activities are unique to normal hematopoietic cells but not to the cancer cell lines evaluated, a potential clinical application of these molecules in the treatment of cancer is suggested.

Preclinical Efficacy and Biological Effects of Venetoclax and Ixazomib in Combination in Lymphoma Cells

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 37-38
Author(s):  
Maria Cosenza ◽  
Stefano Sacchi ◽  
Samantha Pozzi
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Cell Growth ◽  
Cell Lines ◽  
Stromal Cells ◽  
Biological Effects ◽  
Lymphoma Cell ◽  
Lymphoma Cells ◽  
Induction Of Apoptosis ◽  
Preclinical Efficacy

Introduction. Bcl-2 family proteins comprise anti-apoptotic and pro-apoptotic proteins. Interaction between these proteins, as well as severe regulation of their expression, mediates cell survival and can quickly induce cell death. Venetoclax is Bcl-2-targeting that has shown preclinical and clinical activity in hematologic malignancies. Due to the development of resistance and the loss of dependence on the target protein, the monotherapy may be insufficient for maximal effectiveness. To circumvent the resistance mechanisms, many preclinical studies have shown that combination of venetoclax with other agents may represent a more effective therapeutic strategy. Ubiquitin-proteasome signaling pathway is a potential target that plays an important role in the proteolysis of key regulatory proteins. Proteasome inhibitors include ixazomib that inhibits cell growth and induces apoptosis in hematological malignancies cells resistant to conventional therapies and bortezomib. Objective: To analyze the preclinical efficacy and associated biological effects of venetoclax combined with ixazomib in a panel of lymphoma cell lines with diverse expression levels of Bcl-2 and other Bcl-2 family proteins. Methods: 12 lymphoma cell lines including FL (RL, WSU-NHL, Karpas422), MCL (Jeko1, Granta519), DLBCL (OCI-LY3, OCI-LY18), CTCL (Hut-78), ALCL (Karpas299), HL (L1236, L540), CLL (Mec1) and two MCL primary patient samples were exposed to venetoclax (0.01 - 8 µM) and ixazomib (10 - 2000 nM) alone for 24 - 72 hours to calculate IC50. Subsequently, lymphoma cells were exposed to venetoclax (0.015 - 25 nM) in combination with ixazomib (0.015 - 0.5 nM) for 24 hours. Cell viability was determined by MTT. Coefficient of synergy (combination index - CI) was calculated using CalcuSyn. Cell cycle and induction of apoptosis were evaluated by flow cytometry and changes in Bcl-2 family members, caspase activation and AKT phosphorylation were determined by western blotting. Results. In vitro, venetoclax and ixazomib alone induced cell death in a dose- and time-dependent manner against lymphoma cell lines. The IC50 is between 0.5 and 8 µM for venetoclax and between 12 and 1250 nM for ixazomib. The combination of venetoclax (0.03, 0.06, 12.5, 25 nM) with ixazomib (0.03, 0.06, 0.25, 0.5 nM) produced a synergistic effect (CI < 1) after 24 h of treatment in the most lymphoma cells lines leading to inhibition of cell growth and induction of apoptosis between 26 % and 59 % accompanied by increased with cleavage of caspases-3, -9 and PARP. We observed an additive effect (CI = 1) in Jeko1 (MCL) and MEC1 cells (CLL) and antagonist effect (CI > 1) Hut-78 cells (CTCL). Synergistic effect has been seen in two MCL primary patient samples (CI = 0.5 - 0.7). In sensitive lymphoma cells, the combination abrogated colony formation in the methylcellulose medium. When lymphoma cell lines were co-cultured with mesenchymal stromal cells with both drugs we observed a decrease of cell viability and a fraction of apoptotic cells indicating that drug combination may overcome the tumor promoting effects of stromal cells. The apoptosis induced in FL and Granta519 cells (MCL) by drug combination was accompanied by partial downregulation of Bcl-2 and strong upregulation of Bax, Bad, Bim and Noxa proteins. Jeko-1 cells were less sensitive to venetoclax-ixazomib combination-induced apoptosis. Western blot analysis showed a differential expression of Bcl-2, Mcl-1 and Bcl-XL proteins in FL, MCL and HL cell lines. Jeko-1 cells showed a normal expression of Bcl-2 and Mcl-1 proteins and high Bcl-xL protein level. Co-expression of related anti-apoptotic Bcl-2 family proteins could limit activity of treatment. Combined treatment induced G0/G1 cell cycle arrest and increased the sub-G1 population that was linked by the upregulation of p27 and p21. In addition, in RL, WSU-NHL and Granta519, enhanced cell death is associated with AKT inactivation and with a reduction of p-4EBP1, leading to decreased levels of c-MYC. Conclusion. Venetoclax exhibits strong synergistic activity with ixazomib in lymphoma cells. Studies are still ongoing and signaling pathways that promote the combination of venetoclax with ixazomib are to be analyzed. These data offer a rationale to continue exploring venetoclax-ixazomib combination and suggest that suppression of Bcl-2 family protein driven survival signaling may be one important mechanism for combination synergy. Disclosures No relevant conflicts of interest to declare.

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