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Abel EL, Bubel JD, Simper MS, Powell L, McClellan SA, Andreeff M, MacLeod MC, DiGiovanni J. Protection against 2-chloroethyl ethyl sulfide (CEES) — induced cytotoxicity in human keratinocytes by an inducer of the glutathione detoxification pathway. Toxicol Appl Pharmacol 2011; 255:176-83. [DOI: 10.1016/j.taap.2011.06.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 06/06/2011] [Accepted: 06/15/2011] [Indexed: 12/29/2022]
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Benito J, Shi Y, Szymanska B, Carol H, Boehm I, Lu H, Konoplev S, Fang W, Zweidler-McKay PA, Campana D, Borthakur G, Bueso-Ramos C, Shpall E, Thomas DA, Jordan CT, Kantarjian H, Wilson WR, Lock R, Andreeff M, Konopleva M. Pronounced hypoxia in models of murine and human leukemia: high efficacy of hypoxia-activated prodrug PR-104. PLoS One 2011; 6:e23108. [PMID: 21853076 PMCID: PMC3154919 DOI: 10.1371/journal.pone.0023108] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 07/12/2011] [Indexed: 01/10/2023] Open
Abstract
Recent studies indicate that interactions between leukemia cells and the bone marrow (BM) microenvironment promote leukemia cell survival and confer resistance to anti-leukemic drugs. There is evidence that BM microenvironment contains hypoxic areas that confer survival advantage to hematopoietic cells. In the present study we investigated whether hypoxia in leukemic BM contributes to the protective role of the BM microenvironment. We observed a marked expansion of hypoxic BM areas in immunodeficient mice engrafted with acute lymphoblastic leukemia (ALL) cells. Consistent with this finding, we found that hypoxia promotes chemoresistance in various ALL derived cell lines. These findings suggest to employ hypoxia-activated prodrugs to eliminate leukemia cells within hypoxic niches. Using several xenograft models, we demonstrated that administration of the hypoxia-activated dinitrobenzamide mustard, PR-104 prolonged survival and decreased leukemia burden of immune-deficient mice injected with primary acute lymphoblastic leukemia cells. Together, these findings strongly suggest that targeting hypoxia in leukemic BM is feasible and may significantly improve leukemia therapy.
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Sharma M, Ravandi F, Bayraktar UD, Chiattone A, Bashir Q, Giralt S, Chen J, Qazilbash M, Kebriaei P, Konopleva M, Andreeff M, Cortes J, McCue D, Kantarjian H, Champlin RE, de Lima M. Treatment of FLT3-ITD-positive acute myeloid leukemia relapsing after allogeneic stem cell transplantation with sorafenib. Biol Blood Marrow Transplant 2011; 17:1874-7. [PMID: 21767516 DOI: 10.1016/j.bbmt.2011.07.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Accepted: 07/10/2011] [Indexed: 10/17/2022]
Abstract
Patients with acute myeloid leukemia (AML) and internal tandem duplication of FMS-like tyrosine kinase receptor-3 gene (FLT3-ITD) mutation have poor prognoses and are often treated with allogeneic hematopoietic stem cell transplantation (HSCT). Sorafenib, an inhibitor of multiple kinases including FLT3, has shown promising activity in FLT3-ITD-positive AML. We treated 16 patients with FLT3-ITD-positive AML who relapsed after HSCT with sorafenib alone (n = 8) or in combination with cytotoxic chemotherapy (n = 8). The number of circulating blasts decreased in 80% of cases, but none of the patients achieved complete remission (CR); 3 achieved partial remission. Two patients were bridged to a second transplantation but both relapsed within 3 months of the transplantation. Median overall survival (OS) was 83 days, with none surviving more than a year. Sorafenib is not effective in the treatment of FLT3-ITD-positive AML relapsing after HSCT. Preventive strategies after HSCT may be more suitable for these high-risk patients.
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Kojima K, Duvvuri S, Ruvolo V, Samaniego F, Younes A, Andreeff M. Decreased sensitivity of 17p-deleted chronic lymphocytic leukemia cells to a small molecule BCL-2 antagonist ABT-737. Cancer 2011; 118:1023-31. [PMID: 21761401 DOI: 10.1002/cncr.26360] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 05/25/2011] [Accepted: 05/26/2011] [Indexed: 11/11/2022]
Abstract
BACKGROUND Despite the high complete response rates achieved with fludarabine-based regimens, relapse is inevitable in chronic lymphocytic leukemia (CLL). Relapsed patients often acquire deletions of the short arm of chromosome 17 (del[17p]), which are closely associated with tumor protein 53 (TP53) mutations. Wild-type p53 up-regulates and activates B-cell CLL/lymphoma 2 (BCL-2)-associated X protein (BAX), and it down-regulates and inactivates BCL-2. The small-molecule BCL-2 inhibitor ABT-737 induces apoptosis in a BAX-dependent and BCL-2 homologous antagonist-killer (BAK)-dependent manner. The role of p53 in sensitivity of CLL cells to BCL-2 inhibition has not been extensively investigated. METHODS The authors investigated the association of del(17p) with ABT-737 sensitivity in CLL cells from 50 patients. Stable p53 and BAX knockdown cells were used for mechanistic studies. RESULTS CLL cells with del(17p) were less sensitive to ABT-737-induced BAX activation and apoptosis than CLL cells without del(17p) (39% ± 7.3% vs 63.7% ± 2.9% [specific annexin V induction]; P < .01). A positive correlation between the degrees of apoptosis induced by ABT-737 and by the p53-activating binding protein homolog murine double minute (MDM2) antagonist nutlin-3a (correlation coefficient [r] = 0.75; P < .0001) was observed. CLL cells with del(17p) expressed lower levels of BAX than those without del(17p) (0.67 ± 0.12 vs 1.27 ± 0.10 in relative protein expression levels; P < .01). Knockdown of p53 or BAX in leukemia cells resulted in decreased apoptosis induced by ABT-737. CONCLUSIONS The current data indicated that p53 dysfunction may lead to decreased apoptosis induction by ABT-737.
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Badgwell DB, Lu Z, Le K, Gao F, Yang M, Suh GK, Bao JJ, Das P, Andreeff M, Chen W, Yu Y, Ahmed AA, S-L Liao W, Bast RC. The tumor-suppressor gene ARHI (DIRAS3) suppresses ovarian cancer cell migration through inhibition of the Stat3 and FAK/Rho signaling pathways. Oncogene 2011; 31:68-79. [PMID: 21643014 DOI: 10.1038/onc.2011.213] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ovarian cancers migrate and metastasize over the surface of the peritoneal cavity. Consequently, dysregulation of mechanisms that limit cell migration may be particularly important in the pathogenesis of the disease. ARHI is an imprinted tumor-suppressor gene that is downregulated in >60% of ovarian cancers, and its loss is associated with decreased progression-free survival. ARHI encodes a 26-kDa GTPase with homology to Ras. In contrast to Ras, ARHI inhibits cell growth, but whether it also regulates cell motility has not been studied previously. Here we report that re-expression of ARHI decreases the motility of IL-6- and epidermal growth factor (EGF)-stimulated SKOv3 and Hey ovarian cancer cells, inhibiting both chemotaxis and haptotaxis. ARHI binds to and sequesters Stat3 in the cytoplasm, preventing its translocation to the nucleus and localization in focal adhesion complexes. Stat3 siRNA or the JAK2 inhibitor AG490 produced similar inhibition of motility. However, the combination of ARHI expression with Stat3 knockdown or inhibition produced greatest inhibition in ovarian cancer cell migration, consistent with Stat3-dependent and Stat3-independent mechanisms. Consistent with two distinct signaling pathways, knockdown of Stat3 selectively inhibited IL-6-stimulated migration, whereas knockdown of focal adhesion kinase (FAK) preferentially inhibited EGF-stimulated migration. In EGF-stimulated ovarian cancer cells, re-expression of ARHI inhibited FAK(Y397) and Src(Y416) phosphorylation, disrupted focal adhesions, and blocked FAK-mediated RhoA signaling, resulting in decreased levels of GTP-RhoA. Re-expression of ARHI also disrupted the formation of actin stress fibers in a FAK- and RhoA-dependent manner. Thus, ARHI has a critical and previously uncharacterized role in the regulation of ovarian cancer cell migration, exerting inhibitory effects on two distinct signaling pathways.
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Ruvolo PP, Zhou L, Watt JC, Ruvolo VR, Burks JK, Jiffar T, Kornblau S, Konopleva M, Andreeff M. Targeting PKC-mediated signal transduction pathways using enzastaurin to promote apoptosis in acute myeloid leukemia-derived cell lines and blast cells. J Cell Biochem 2011; 112:1696-707. [PMID: 21360576 PMCID: PMC3394435 DOI: 10.1002/jcb.23090] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Recent studies in acute myeloid leukemia (AML) suggest activation of pro-proliferative signaling cascades including those mediated by protein kinase C (PKC) represent a poor prognostic factor for patients. The classical PKC isoforms α and β generally support survival signaling and have emerged as important targets for anti-cancer therapy. Enzastaurin is a PKC β inhibitor and is in clinical trials for lymphomas, gliomas, and lung cancer. Presently, it is not known if enzastaurin could be effective against AML. In the current study, we found that high dose enzastaurin was found to promote apoptosis in the AML-derived cell lines and in blast cells from AML patients. The mechanism of cell death, however, likely does not involve PKC β as another PKC β inhibitor was not toxic to AML cell lines and did not promote enzastaurin-induced cell killing. While enzastaurin is fairly specific for PKC β, the agent can inhibit other PKC isoforms at higher concentrations. Enzastaurin was effective at inhibiting PKC α phosphorylation and membrane localization in the AML cell lines and suppressed phosphorylation of BCL2. Furthermore, enzastaurin suppressed activation of ERK (which can be activated by PKC α). Analysis of the serine/threonine phosphorylation profile in HL60 cells after enzastaurin treatment revealed that the drug inhibits the phosphorylation of a distinct set of proteins while promoting phosphorylation of another set of proteins. This suggests the drug may regulate multiple signaling pathways. Taken together, these findings suggest that enzastaurin could be effective in the therapy of AML.
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Beryozkina A, Nichols GL, Reckner M, Vassilev LT, Rueger R, Jukofsky L, Middleton S, Andreeff M, Padmanabhan S, Strair R, Delioukina ML, Maslak PG, Hillmen P, Kurzrock R, Gore L, Patnaik A, Maki RG, Schwartz GK, Wagner AJ, Zhi J. Pharmacokinetics (PK) and pharmacodynamics (PD) of RG7112, an oral murine double minute 2 (MDM2) antagonist, in patients with leukemias and solid tumors. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.3039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Kang SG, Shinojima N, Hossain A, Gumin J, Yong RL, Colman H, Marini F, Andreeff M, Lang FF. Isolation and perivascular localization of mesenchymal stem cells from mouse brain. Neurosurgery 2011; 67:711-20. [PMID: 20651630 DOI: 10.1227/01.neu.0000377859.06219.78] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Although originally isolated from the bone marrow, mesenchymal stem cells (MSCs) have recently been detected in other tissues. However, little is known about MSCs in the brain. OBJECTIVE To determine the extent to which cells with the features of MSCs exist in normal brain tissue and to determine the location of these cells in the brain. METHODS Single-cell suspensions from mouse brains were cultured according to the same methods used for culturing bone marrow-derived MSCs (BM-MSCs). These brain-derived cells were analyzed by fluorescence-activated cell sorting for surface markers associated with BM-MSCs (stem cell antigen 1 [Sca-1+], CD9+, CD45-, CD11b-, and CD31-). Brain-derived cells were exposed to mesenchymal differentiation conditions. To determine the locations of these cells within the brain, sections of normal brains were analyzed by immunostaining for Sca-1, CD31, and nerve/glial antigen 2. RESULTS Cells morphologically similar to mouse BM-MSCs were identified and called brain-derived MSCs (Br-MSCs). Fluorescence-activated cell sorting indicated that the isolated cells had a surface marker profile similar to BM-MSCs, ie, Sca-1V+, CD9+, CD45-, and CD11b-. Like BM-MSCs, Br-MSCs were capable of differentiation into adipocytes, osteocytes, and chondrocytes. Immunostaining indicated that Sca-1+ Br-MSCs are located around blood vessels and may represent progenitor cells that serve as a source of mesenchymal elements (eg, pericytes) within the brain. CONCLUSION Our results indicate that cells similar to BM-MSCs exist in the brain. These Br-MSCs appear to be located within the vascular niche and may provide the mesenchymal elements of this niche. Because MSCs may be part of the cellular response to tissue injury, Br-MSCs may represent targets in the therapy of pathological processes such as stroke, trauma, and tumorigenesis.
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Abel EL, McIvor E, Bubel JD, Simper MS, Powell L, Fields TY, Andreeff M, MacLeod MC, DiGiovanni J. Abstract 1339: Upregulation of the glutathione detoxification pathway protects against cytotoxicity induced by the alkylating agent, 2-chloroethyl ethyl sulfide (CEES). Cancer Res 2011. [DOI: 10.1158/1538-7445.am2011-1339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Sulfur mustard (SM) is a vesicating agent that was first used in chemical warfare over 100 years ago. SM alkylates DNA and is mutagenic in various model systems. Epidemiological studies indicate that chronic exposure increases the risk of cancer in exposed tissues. Due to its incapacitating effects, and the relative ease with which it may be synthesized, mustard gas remains a potential chemical threat to the present day. Currently, there are no antidotes for SM-induced toxicity; therefore, chemopreventive and therapeutic measures are needed. Glutathione (GSH) exerts a protective effect against SM toxicity, and detoxification of SM is believed to occur, in part, via GSH conjugation. The rate-limiting step in GSH synthesis is catalyzed by the glutamate cysteine ligase (GCL) holoenzyme, which is composed of a catalytic and a regulatory subunit (GCLC and GCLM, respectively). Cancer chemopreventive agents are known to modulate expression of GCL and GSH S-transferases (GSTs) via activation of the transcription factor, Nrf2, and may, therefore, have utility in inhibiting SM-induced damage in the skin. We have screened 6 chemopreventive agents for ability to induce GSH synthesis and protect cultured NCTC2544 human keratinocytes against the SM analogue, 2-chloroethyl ethyl sulfide (CEES). We found that sulforaphane and methyl-2-cyano-3,12-dioxooleana-1,9-dien-28-oate (CDDO-Me) stimulated nuclear localization of Nrf2 and induced expression of GCLM. Additionally, we found that treatment with CDDO-Me elevated reduced GSH content of NCTC2544 cells (118.0±11.6 nmol/mg protein versus 66.5±7.9 nmol/mg protein) and preserved their viability by ∼3-fold following exposure to CEES. CDDO-Me acted additively with 2,6-dithiopurine (DTP), a nucleophilic scavenging agent, to increase the viability of keratinocytes exposed to CEES by 6-fold (60% in cells treated with a combination of CDDO-Me and DTP vs 10% in cells treated with vehicle only). In vivo, topical application of either sulforaphane or CDDO-Me elevated epidermal GSH and GST levels in the skin of C57BL/6 mice. These results suggest that CDDO-Me and sulforaphane are promising chemopreventive agents for SM toxicity in the skin.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1339. doi:10.1158/1538-7445.AM2011-1339
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Haase R, Hietschold V, Andreeff M, Böhme HJ, Abolmaali N. Virtuelle Ameisen zur Segmentierung von Positronen-Emissions-Tomographie Daten: Auswirkungen auf die Receiver Operating Characteristic. ROFO-FORTSCHR RONTG 2011. [DOI: 10.1055/s-0031-1279554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Havelange V, Stauffer N, Heaphy CCE, Volinia S, Andreeff M, Marcucci G, Croce CM, Garzon R. Functional implications of microRNAs in acute myeloid leukemia by integrating microRNA and messenger RNA expression profiling. Cancer 2011; 117:4696-706. [PMID: 21455993 DOI: 10.1002/cncr.26096] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 01/11/2011] [Accepted: 02/09/2011] [Indexed: 01/11/2023]
Abstract
BACKGROUND The expression of microRNAs (miRNAs) is deregulated in acute myeloid leukemia (AML), but the corresponding functional miRNA-controlled pathways are poorly understood. Integration of messenger RNA (mRNA) and miRNA expression profiling may allow the identification of functional links between the whole transcriptome and microRNome that are involved in myeloid leukemogenesis. METHODS We integrated miRNA and mRNA expression profiles obtained from 48 newly diagnosed AML patients by using 2 different microarray platforms and performed correlation, gene ontology, and network analysis. Experimental validation was also performed in AML cell lines using miRNA oligonucleotide mimics and functional assays. RESULTS Our analysis identified a strong positive correlation between HOX-related genes and miR-10 and miR-20a. Furthermore, we observed a negative correlation between miR-181a and miR-181b, miR-155, and miR-146 expression with that of genes involved in immunity and inflammation (eg, IRF7 and TLR4) and a positive correlation between miR-23a, miR-26a, miR-128a, and miR-145 expression with that of proapoptotic genes (eg, BIM and PTEN). These correlations were confirmed by gene ontology analyses, which revealed the enrichment of members of the homeobox, immunity and inflammation, and apoptosis biological processes. Furthermore, we validated experimentally the association of miR-145, miR-26a, and miR-128a with apoptosis in AML. CONCLUSION Our results indicate that by integrating the transcriptome and microRNome in AML cells, it is possible to identify previously unidentified putative functional miRNA-mRNA interactions in AML.
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Carter BZ, Mak DH, Cortes J, Andreeff M. The elusive chronic myeloid leukemia stem cell: does it matter and how do we eliminate it? Semin Hematol 2011; 47:362-70. [PMID: 20875553 DOI: 10.1053/j.seminhematol.2010.06.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Chronic myeloid leukemia (CML) is a clonal multistep myeloproliferative disease originating from and ultimately sustained by a rare population of BCR-ABL(+) cells with multilineage stem cell properties. Imatinib, the most successful of molecular targeted therapies, has revolutionized treatment of patients with CML. Despite this achievement, CML is often not curable, largely due to the innate insensitivity of CML stem cells, particularly when in a quiescent state. This failure of not only imatinib but also the second-generation tyrosine kinase inhibitors (TKIs) frequently leads to relapse upon drug discontinuation. Thus, any curative therapy must eliminate CML stem cells. A comprehensive understanding of the biological properties of CML stem cells and an elucidation of the molecular mechanisms and signaling pathways enabling these CML stem cells to self-renew, combined with insight into the regulation of apoptosis signaling and the mechanisms governing the interaction of CML stem cells with their bone marrow microenvironment, will facilitate the development of therapies for targeting these cells. Here, we discuss the biological properties of CML stem cells and potential strategies to eliminate them.
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Battula VL, Evans KW, Hollier BG, Shi Y, Marini FC, Ayyanan A, Wang RY, Brisken C, Guerra R, Andreeff M, Mani SA. Epithelial-mesenchymal transition-derived cells exhibit multilineage differentiation potential similar to mesenchymal stem cells. Stem Cells 2011; 28:1435-45. [PMID: 20572012 DOI: 10.1002/stem.467] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The epithelial-to-mesenchymal transition (EMT) is an embryonic process that becomes latent in most normal adult tissues. Recently, we have shown that induction of EMT endows breast epithelial cells with stem cell traits. In this report, we have further characterized the EMT-derived cells and shown that these cells are similar to mesenchymal stem cells (MSCs) with the capacity to differentiate into multiple tissue lineages. For this purpose, we induced EMT by ectopic expression of Twist, Snail, or transforming growth factor-beta in immortalized human mammary epithelial cells. We found that the EMT-derived cells and MSCs share many properties including the antigenic profile typical of MSCs, that is, CD44(+), CD24(-), and CD45(-). Conversely, MSCs express EMT-associated genes, such as Twist, Snail, and mesenchyme forkhead 1 (FOXC2). Interestingly, CD140b (platelet-derived growth factor receptor-beta), a marker for naive MSCs, is exclusively expressed in EMT-derived cells and not in their epithelial counterparts. Moreover, functional analyses revealed that EMT-derived cells but not the control cells can differentiate into alizarin red S-positive mature osteoblasts, oil red O-positive adipocytes and alcian blue-positive chondrocytes similar to MSCs. We also observed that EMT-derived cells but not the control cells invade and migrate towards MDA-MB-231 breast cancer cells similar to MSCs. In vivo wound homing assays in nude mice revealed that the EMT-derived cells home to wound sites similar to MSCs. In conclusion, we have demonstrated that the EMT-derived cells are similar to MSCs in gene expression, multilineage differentiation, and ability to migrate towards tumor cells and wound sites.
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Klopp AH, Gupta A, Spaeth E, Andreeff M, Marini F. Concise review: Dissecting a discrepancy in the literature: do mesenchymal stem cells support or suppress tumor growth? Stem Cells 2011; 29:11-9. [PMID: 21280155 PMCID: PMC3059412 DOI: 10.1002/stem.559] [Citation(s) in RCA: 408] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 10/20/2010] [Indexed: 12/14/2022]
Abstract
The discovery that mesenchymal stem cells (MSCs) are recruited into tumors has led to a great deal of interest over the past decade in the function of MSCs in tumors. To address this, investigators have used a variety of tumor models in which MSCs are added exogenously to determine their impact on tumor development. Interestingly, many studies have reported contradicting results, with some investigators finding that MSCs promote tumor growth and others reporting that MSCs inhibit tumor growth. Many mechanisms have been reported to account for these observations, such as chemokine signaling, modulation of apoptosis, vascular support, and immune modulation. In this review, we analyzed the differences in the methodology of the studies reported and found that the timing of MSC introduction into tumors may be a critical element. Understanding the conditions in which MSCs enhance tumor growth and metastasis is crucial, both to safely develop MSCs as a therapeutic tool and to advance our understanding of the role of tumor stroma in carcinogenesis.
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Borthakur G, Kantarjian H, Ravandi F, Zhang W, Konopleva M, Wright JJ, Faderl S, Verstovsek S, Mathews S, Andreeff M, Cortes JE. Phase I study of sorafenib in patients with refractory or relapsed acute leukemias. Haematologica 2011; 96:62-8. [PMID: 20952518 PMCID: PMC3012766 DOI: 10.3324/haematol.2010.030452] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
UNLABELLED Background Sorafenib is a multi-kinase inhibitor with activity against fms-like tyrosine kinase 3 with internal tandem duplication mutation and Raf kinase among others. A phase I dose escalation study of sorafenib was conducted in patients with advanced myelodysplastic syndrome and relapsed or refractory acute leukemias. DESIGN AND METHODS Fifty patients received one of two different schedules; Schedule "A": once or twice daily, five days per week, every week for a 21 day cycle, and Schedule "B": once or twice daily, for 14 days every 21 days. Dose limiting toxicities were grade 3/4 hypertension, hyperbilirubinemia, and amylase elevation. The recommended phase II dose in hematologic malignancies is 400 mg twice daily for both schedules. RESULTS Complete remissions or complete remissions with incomplete recovery of platelets were achieved in 5 (10%) patients (all with fms-like tyrosine kinase 3-internal tandem duplication). Significant reduction in bone marrow and/or peripheral blood blasts was seen in an additional 17 (34%) patients (all with fms-like tyrosine kinase 3-internal tandem duplication). Eleven of these responses (including 3 complete remissions/complete remissions with incomplete recovery) lasted for 2 cycles or beyond. In conclusion, sorafenib is active and well tolerated in acute myelogenous leukemia with fms-like tyrosine kinase 3 internal tandem duplication mutation. Conclusions Additional studies of sorafenib in patients with acute myelogenous leukemia, particularly those with fms-like tyrosine kinase 3 internal tandem duplication, are warranted, including sorafenib-based combinations. (ClinicalTrials.gov Identifier: NCT00217646).
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Carter BZ, Mak DH, Morris SJ, Borthakur G, Estey E, Byrd AL, Konopleva M, Kantarjian H, Andreeff M. XIAP antisense oligonucleotide (AEG35156) achieves target knockdown and induces apoptosis preferentially in CD34+38- cells in a phase 1/2 study of patients with relapsed/refractory AML. Apoptosis 2011; 16:67-74. [PMID: 20938744 PMCID: PMC3376026 DOI: 10.1007/s10495-010-0545-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
XIAP, a potent caspase inhibitor, is highly expressed in acute myeloid leukemia (AML) cells and contributes to chemoresistance. A multi-center phase 1/2 trial of XIAP antisense oligonucleotide AEG35156 in combination with idarubicin/cytarabine was conducted in 56 patients with relapsed/refractory AML. Herein we report the pharmacodynamic studies of the patients enrolled at M. D. Anderson Cancer Center. A total of 13 patients were enrolled in our institution: five in phase 1 (12-350 mg/m² AEG35156) and eight in phase 2 (350 mg/m² AEG35156) of the protocol. AEG35156 was administered on 3 consecutive days and then weekly up to a maximum of 35 days. Blood samples were collected from patients on days 1 through 5 and on day 28-35 post-chemotherapy for detection of XIAP levels and apoptosis. AEG35156 treatment led to dose-dependent decreases of XIAP mRNA levels (42-100% reduction in phase 2 patients). XIAP protein levels were reduced in all five samples measured. Apoptosis induction was detected in 1/4 phase 1 and 4/5 phase 2 patients. Importantly, apoptosis was most pronounced in CD34+38- AML stem cells and all phase 2 patients showing apoptosis induction in CD34+38- cells achieved response. We conclude that at 350 mg/m², AEG35156 is effective in knocking down XIAP in circulating blasts accompanied by the preferential induction of apoptosis in CD34+38- AML stem cells.
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Lacerda L, Gupta A, Debeb BG, Xu W, Meyn R, Marini F, Andreeff M, Woodward WA, Klopp AH. Abstract PD02-07: Impact of Mesenchymal Stem Cells on Radiation Therapy Response. Cancer Res 2010. [DOI: 10.1158/0008-5472.sabcs10-pd02-07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Radiation increases engraftment of human bone-marrow derived mesenchymal stem cells (MSC) in tumors and this effect is augmented following repeated doses of radiation. We have recently demonstrated that MSC increase formation of mammospheres, which are enriched with radiation resistant tumor-initiating cells. Thus, we hypothesized that MSC may impact radiation therapy response through enhanced survival of tumor-initiating cells.
Materials & Methods: To evaluate the impact of MSC on radiation response we performed in vitro clonogenic survival assays using 2D and 3D clonogenic assays. Colony (2D) and sphere (3D) formation was quantified following irradiation of different cell lines (breast, lung, head and neck and cervix) at 2, 4 and 6 Gy in the presence of MSC conditioned media. In vivo, MSC were co-injected subcutaneously at increasing percentages with 4T1 murine breast cancer cells in BALB/c mice. The effects of MSC on radiation response were evaluated by examination of tumor size and weight following tumor irradiation at 2 and 5 Gy. Results: In vitro 2D clonogenic cell survival assays demonstrated that MSC conditioned media increased survival of breast (MDA231), lung (H460), head and neck (HN5), and cervical (SiHa) cancer cells following irradiation with 2 and 4 Gy as compared to control fibroblast conditioned media. Moreover, MSC conditioned media increased the number of HMLE (breast normal ephitelial cells) and SUM149 (breast cancer cells) mammospheres formed (55 vs 195and 263 vs 1054, respectively) and increased clonogenic survival of mammospheres after 2, 4 and 6 Gy compared to serum-free media. In vivo, irradiation with 5 Gy reduced murine breast 4T1tumors weight by 75% as compared to control untreated tumors. However, tumors co-injected with MSC did not significantly respond to 5 Gy. Discussion: MSC increase tumor resistance to radiation therapy in vivo and in vitro in 2D and 3D cultures. This effect is mediated at least in part by paracrine factors secreted by MSC. Our results here described suggest that MSC secrete factors which activate survival pathways on cancer cells exposed to sub-lethal radiation doses.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD02-07.
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Kotzerke J, Andreeff M, Wunderlich G, Wiggermann P, Zöphel K. [Ventilation-perfusion-lungscintigraphy using PET and 68Ga-labeled radiopharmaceuticals]. Nuklearmedizin 2010; 49:203-8. [PMID: 21057723 DOI: 10.3413/nukmed-0348-10-09] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2010] [Accepted: 11/05/2010] [Indexed: 11/20/2022]
Abstract
AIM Imaging of lung perfusion with positron emission tomography (PET) is already possible with 68Ga labeled denaturized albumin. The purpose of our study was to produce and test a 68Ga labeled aerosol (Galligas®) for ventilation and 68Ga labeled albumin particles (microspheres) for perfusion imaging with PET. PATIENTS, METHODS Galligas was produced by simmering and burning generator eluted 68Ga solution (100 MBq/0.1 ml) in an ordinary technegas generator. Fifteen patients with suspicion on pulmonary embolism underwent PET/CT (Biograph 16) after inhalation of Galligas and application of 68Ga labeled microspheres. A low dose CT was acquired for attenuation correction (AC). Images were reconstructed with and without AC. The inhaled activity was calculated compared to the activity injected. RESULTS Inhaled radioaerosol Galligas demonstrated typical distribution as known from 99mTc-labeled technegas with homogeneous distribution in lung without hilar deposits. Attenuation corrected images resulted in artefacts in the lung base. Therefore, non-corrected images were used for making the results. Three out of fifteen patients showed a deficient perfusion whereas ventilation was normal corresponding to pulmonary embolism. CONCLUSION Lung scintigraphy with PET is feasible. Galligas is simple to produce (analogously to technegas). 68Ga labeled microspheres are available. The method is applicable to daily routine and rendered clinically relevant informations.
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369
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Saha PK, Reddy VT, Konopleva M, Andreeff M, Chan L. The triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic-acid methyl ester has potent anti-diabetic effects in diet-induced diabetic mice and Lepr(db/db) mice. J Biol Chem 2010; 285:40581-92. [PMID: 20956520 DOI: 10.1074/jbc.m110.176545] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The triterpenoid 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic-acid (CDDO) and its methyl ester (CDDO-Me) are undergoing clinical trials in cancer and leukemia therapy. Here we report that CDDO-Me ameliorates diabetes in high fat diet-fed type 2 diabetic mice and in Lepr(db/db) mice. CDDO-Me reduces proinflammatory cytokine expression in these animals. Oral CDDO-Me administration reduces total body fat, plasma triglyceride, and free fatty acid levels. It also improves glucose tolerance and insulin tolerance tests. Its potent glucose-lowering activity results from enhanced insulin action. Hyperinsulinemic-euglycemic clamp reveals an increased glucose infusion rate required to maintain euglycemia and showed a significant increase in muscle-specific insulin-stimulated glucose uptake (71% soleus, 58% gastrocnemius) and peripheral glucose clearance as documented by a 48% increase in glucose disposal rate. CDDO-Me activates AMP-activated protein kinase (AMPK) and via LKB1 activation in muscle and liver in vivo. Treatment of isolated hepatocytes with CDDO-Me directly stimulates AMPK activity and LKB1 phosphorylation and decreases acetyl-coA carboxylase activity; it also down-regulates lipogenic gene expression, suppresses gluconeogenesis, and increases glucose uptake. Inhibition of AMPK phosphorylation using compound C and lentiviral-mediated knockdown of AMPK completely blocks the CDDO-Me-induced effect on hepatocytes as well as C(2)C(12) cells. We conclude that the triterpenoid CDDO-Me has potent anti-diabetic action in diabetic mouse models that is mediated at least in part through AMPK activation. The in vivo anti-diabetogenic effects occur at a dose substantially lower than that used for anti-leukemia therapy. We suggest that CDDO-Me holds promise as a potential anti-diabetic agent.
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Dasgupta SK, Argaiz ER, Mercado JEC, Maul HOE, Garza J, Enriquez AB, Abdel-Monem H, Prakasam A, Andreeff M, Thiagarajan P. Platelet senescence and phosphatidylserine exposure. Transfusion 2010; 50:2167-75. [PMID: 20456701 PMCID: PMC2921562 DOI: 10.1111/j.1537-2995.2010.02676.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The exposure of phosphatidylserine occurs during platelet (PLT) activation and during in vitro storage. Phosphatidylserine exposure also occurs during apoptosis after the release of mitochondrial cytochrome c. We have examined the role of cytochrome c release, mitochondrial membrane potential (ΔΨm), and cyclophilin D (CypD) in phosphatidylserine exposure due to activation and storage. STUDY DESIGN AND METHODS The exposure of phosphatidylserine and the loss of ΔΨm were determined in a flow cytometer using fluorescein isothiocyanate-lactadherin and JC-1, a lipophilic cationic reporter dye. The role of CypD was determined with cyclosporin A and CypD-deficient murine PLTs. Cytochrome c-induced caspase-3 and Rho-associated kinase I (ROCK1) activation were determined by immunoblotting and using their inhibitors. RESULTS Collagen- and thrombin-induced exposure of phosphatidylserine was accompanied by a decrease in ΔΨm. Cyclosporin A inhibited the phosphatidylserine exposure and the loss of ΔΨm. CypD(-/-) mice had decreased loss of ΔΨm and impaired phosphatidylserine exposure. Collagen and thrombin did not induce the release of cytochrome c nor the activation of caspase-3 and ROCK1. In contrast, in PLTs stored for more than 5 days, the phosphatidylserine exposure was associated with cytochrome c-induced caspase-3 and ROCK1 activation. ABT737, a BH3 mimetic that induces mitochondrial pathway of apoptosis, induced cytochrome c release and activation of caspase-3 and ROCK1 and phosphatidylserine exposure independent of CypD. CONCLUSION These results show that in stored PLTs cytochrome c release and the subsequent activation of caspase-3 and ROCK1 mediate phosphatidylserine exposure and it is distinct from activation-induced phosphatidylserine exposure.
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Kidd S, Caldwell L, Dietrich M, Samudio I, Spaeth EL, Watson K, Shi Y, Abbruzzese J, Konopleva M, Andreeff M, Marini FC. Mesenchymal stromal cells alone or expressing interferon-beta suppress pancreatic tumors in vivo, an effect countered by anti-inflammatory treatment. Cytotherapy 2010; 12:615-25. [PMID: 20230221 DOI: 10.3109/14653241003631815] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AIMS Because of the inflammatory nature and extensive stromal compartment in pancreatic tumors, we investigated the role of mesenchymal stromal cells (MSC) to engraft selectively in pancreatic carcinomas and serve as anti-tumor drug delivery vehicles to control pancreatic cancer progression. METHODS Human pancreatic carcinoma cells, PANC-1, expressing renilla luciferase were orthotopically implanted into SCID mice and allowed to develop for 10 days. Firefly luciferase-transduced MSC or MSC expressing interferon (IFN)-beta were then injected intraperitoneally weekly for 3 weeks. Mice were monitored by bioluminescent imaging for expression of renilla (PANC-1) and firefly (MSC) luciferase. RESULTS MSC selectively homed to sites of primary and metastatic pancreatic tumors and inhibited tumor growth (P=0.032). The production of IFN-beta within the tumor site by MSC-IFN-beta further suppressed tumor growth (P=0.0000083). Prior studies indicated that MSC home to sites of inflammation; therefore, we sought to alter the tumor microenvironment through treatment with a potent anti-inflammatory agent. After treatment, inflammation-associated mediators were effectively down-regulated, including NFkappaB, vascular endothelial growth factor (VEGF) and interleukin (IL)-6 as well as chemokines involved in MSC migration (CCL3 and CCL25). Treatment with the anti-inflammatory agent CDDO-Me before and after MSC-IFN-beta injections resulted in reduction of MSC in the tumors and reversed the positive effect of tumor inhibition by MSC-IFN-beta alone (P=0.041). CONCLUSIONS These results suggest that MSC exhibit innate anti-tumor effects against PANC-1 cells and can serve as delivery vehicles for IFN-beta for the treatment of pancreatic cancer. However, these beneficial effects may be lost in therapies combining MSC with anti-inflammatory agents.
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Kojima K, Burks JK, Arts J, Andreeff M. The novel tryptamine derivative JNJ-26854165 induces wild-type p53- and E2F1-mediated apoptosis in acute myeloid and lymphoid leukemias. Mol Cancer Ther 2010; 9:2545-57. [PMID: 20736344 DOI: 10.1158/1535-7163.mct-10-0337] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The development of small-molecule activators of p53 is currently focused on malignancies containing a wild-type p53 genotype, which is present in most leukemias. JNJ-26854165 is one such p53-activating agent, but its mechanism of action remains to be elucidated. Here, we report the effects of JNJ-26854165 in acute leukemias. JNJ-26854165 treatment induced p53-mediated apoptosis in acute leukemia cells with wild-type p53, in which p53 rapidly drives transcription-independent apoptosis followed by activation of a transcription-dependent pathway. JNJ-26854165 accelerated the proteasome-mediated degradation of p21 and antagonized the transcriptional induction of p21 by p53. Interestingly, JNJ-26854165 induced S-phase delay and upregulated E2F1 expression in p53 mutant cells, resulting in apoptosis preferentially of S-phase cells. E2F1 knockdown blocked apoptosis induced by JNJ-26854165 in p53 mutant cells. Apoptotic activity of JNJ-26854165 against primary acute leukemia cells was maintained in leukemia/stroma cocultures, unlike doxorubicin, which has reduced cytrotoxicity in coculture systems. JNJ-26854165 synergizes with 1-β-arabinofuranosylcytosine or doxorubicin to induce p53-mediated apoptosis. Our data suggest that JNJ-26854165 may provide a novel therapeutic approach for the treatment of acute leukemias. The presence of p53-independent apoptotic activity in addition to p53-mediated apoptosis induction, if operational in vivo, may prevent the selection of p53 mutant subclones during therapy.
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Thomas DA, O'Brien S, Faderl S, Garcia-Manero G, Ferrajoli A, Wierda W, Ravandi F, Verstovsek S, Jorgensen JL, Bueso-Ramos C, Andreeff M, Pierce S, Garris R, Keating MJ, Cortes J, Kantarjian HM. Chemoimmunotherapy with a modified hyper-CVAD and rituximab regimen improves outcome in de novo Philadelphia chromosome-negative precursor B-lineage acute lymphoblastic leukemia. J Clin Oncol 2010; 28:3880-9. [PMID: 20660823 PMCID: PMC2940403 DOI: 10.1200/jco.2009.26.9456] [Citation(s) in RCA: 297] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE The adverse prognosis of CD20 expression in adults with de novo precursor B-lineage acute lymphoblastic leukemia (ALL) prompted incorporation of monoclonal antibody therapy with rituximab into the intensive chemotherapy regimen hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone). Other modifications (irrespective of CD20 expression) included early anthracycline intensification, alterations in number of risk-adapted intrathecal chemotherapy treatments for CNS prophylaxis, additional early and late intensifications, and extension of maintenance phase chemotherapy by 6 months. PATIENTS AND METHODS Two hundred eighty-two adolescents and adults with de novo Philadelphia chromosome (Ph)-negative precursor B-lineage ALL were treated with standard or modified hyper-CVAD regimens. The latter incorporated standard-dose rituximab if CD20 expression > or = 20%. RESULTS The complete remission (CR) rate was 95% with 3-year rates of CR duration (CRD) and survival (OS) of 60% and 50%, respectively. In the younger (age < 60 years) CD20-positive subset, rates of CRD and OS were superior with the modified hyper-CVAD and rituximab regimens compared with standard hyper-CVAD (70% v 38%; P < .001% and 75% v 47%, P = .003). In contrast, rates of CRD and OS for CD20-negative counterparts treated with modified versus standard hyper-CVAD regimens were similar (72% v 68%, P = not significant [NS] and 64% v 65%, P = NS, respectively). Older patients with CD20-positive ALL did not benefit from rituximab-based chemoimmunotherapy (rates of CRD 45% v 50%, P = NS and OS 28% v 32%, P = NS, respectively), related in part to deaths in CR. CONCLUSION The incorporation of rituximab into the hyper-CVAD regimen appears to improve outcome for younger patients with CD20-positive Ph-negative precursor B-lineage ALL.
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Klopp AH, Lacerda L, Gupta A, Debeb BG, Solley T, Li L, Spaeth E, Xu W, Zhang X, Lewis MT, Reuben JM, Krishnamurthy S, Ferrari M, Gaspar R, Buchholz TA, Cristofanilli M, Marini F, Andreeff M, Woodward WA. Mesenchymal stem cells promote mammosphere formation and decrease E-cadherin in normal and malignant breast cells. PLoS One 2010; 5:e12180. [PMID: 20808935 PMCID: PMC2922340 DOI: 10.1371/journal.pone.0012180] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 07/26/2010] [Indexed: 02/03/2023] Open
Abstract
INTRODUCTION Normal and malignant breast tissue contains a rare population of multi-potent cells with the capacity to self-renew, referred to as stem cells, or tumor initiating cells (TIC). These cells can be enriched by growth as "mammospheres" in three-dimensional cultures. OBJECTIVE We tested the hypothesis that human bone-marrow derived mesenchymal stem cells (MSC), which are known to support tumor growth and metastasis, increase mammosphere formation. RESULTS We found that MSC increased human mammary epithelial cell (HMEC) mammosphere formation in a dose-dependent manner. A similar increase in sphere formation was seen in human inflammatory (SUM149) and non-inflammatory breast cancer cell lines (MCF-7) but not in primary inflammatory breast cancer cells (MDA-IBC-3). We determined that increased mammosphere formation can be mediated by secreted factors as MSC conditioned media from MSC spheroids significantly increased HMEC, MCF-7 and SUM149 mammosphere formation by 6.4 to 21-fold. Mammospheres grown in MSC conditioned media had lower levels of the cell adhesion protein, E-cadherin, and increased expression of N-cadherin in SUM149 and HMEC cells, characteristic of a pro-invasive mesenchymal phenotype. Co-injection with MSC in vivo resulted in a reduced latency time to develop detectable MCF-7 and MDA-IBC-3 tumors and increased the growth of MDA-IBC-3 tumors. Furthermore, E-cadherin expression was decreased in MDA-IBC-3 xenografts with co-injection of MSC. CONCLUSIONS MSC increase the efficiency of primary mammosphere formation in normal and malignant breast cells and decrease E-cadherin expression, a biologic event associated with breast cancer progression and resistance to therapy.
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Ahmed AA, Lu Z, Jennings NB, Etemadmoghadam D, Capalbo L, Jacamo RO, Barbosa-Morais N, Le XF, Vivas-Mejia P, Lopez-Berestein G, Grandjean G, Bartholomeusz G, Liao W, Andreeff M, Bowtell D, Glover DM, Sood AK, Bast RC. SIK2 is a centrosome kinase required for bipolar mitotic spindle formation that provides a potential target for therapy in ovarian cancer. Cancer Cell 2010; 18:109-21. [PMID: 20708153 PMCID: PMC3954541 DOI: 10.1016/j.ccr.2010.06.018] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 05/02/2010] [Accepted: 07/02/2010] [Indexed: 01/30/2023]
Abstract
Regulators of mitosis have been successfully targeted to enhance response to taxane chemotherapy. Here, we show that the salt inducible kinase 2 (SIK2) localizes at the centrosome, plays a key role in the initiation of mitosis, and regulates the localization of the centrosome linker protein, C-Nap1, through S2392 phosphorylation. Interference with the known SIK2 inhibitor PKA induced SIK2-dependent centrosome splitting in interphase while SIK2 depletion blocked centrosome separation in mitosis, sensitizing ovarian cancers to paclitaxel in culture and in xenografts. Depletion of SIK2 also delayed G1/S transition and reduced AKT phosphorylation. Higher expression of SIK2 significantly correlated with poor survival in patients with high-grade serous ovarian cancers. We believe these data identify SIK2 as a plausible target for therapy in ovarian cancers.
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