RESUMO
Exosomes are nanoscale extracellular vesicles which regulate intercellular communication. They have great potential for application in nanomedicine. However, techniques for their isolation are limited by requirements for advanced instruments and costly reagents. In this study, we developed a lyophilization-based method for isolating exosomes from cultured cells. The isolated exosomes were characterized for protein content using Bradford assay, and for size distribution and shape using scanning electron microscopy (SEM) and nanoparticles tracking analysis (NTA). In addition, CD63, CD9, CD81, HSP70 and TSG101 were evaluated as essential exosomal surface markers using Western blot. Drug loading and release studies were performed to confirm their drug delivery properties using an in vitro model. Exosomes were also loaded with commercial dyes (Cy5, Eosin) for the evaluation of their drug delivery properties. All these characterizations confirmed successful exosome isolation with measurements of less than 150 nm, having a typical shape, and by expressing the known exosome surface protein markers. Finally, tyrosine kinase inhibitors (dasatinib and ponatinib) were loaded on the exosomes to evaluate their anticancer effects on leukemia cells (K562 and engineered Ba/F3-BCR-ABL) using MTT and Annexin-PI assays. The expression of MUC1 protein on the exosomes isolated from MCF-7 cells also indicated that their potential diagnostic properties were intact. In conclusion, we developed a new method for exosome isolation from cultured cells. These exosomes met all the essential requirements in terms of characterization, drug loading and release ability, and inhibition of proliferation and apoptosis induction in Ph+ leukemia cells. Based on these results, we are confident in presenting the lyophilization-based exosome isolation method as an alternative to traditional techniques for exosome isolation from cultured cells.
Assuntos
Exossomos , Vesículas Extracelulares , Leucemia , Humanos , Exossomos/metabolismo , Células Cultivadas , Indicadores e Reagentes , Leucemia/metabolismoRESUMO
Objectives: The present study is a scoping review of the progress of the field of stem cell research (SCR) in Pakistan in the last two decades. METHODS: Data was extracted from electronic search engines, international clinical trial registry platforms, and PubMed and presented in tabular and graphical form. RESULTS: China, India and Iran are investing heavily in SCR. In Pakistan, reasonable growth in terms of the number of publications is observed in this area, however, clinical translation of the field does not demonstrate any considerable progress. The Government of Pakistan has developed the regulatory framework and initiated preliminary policymaking, adopting rules from international regulatory agencies like World Health Organization (WHO) and Federal Drug Authority (FDA), however, further clarity and policymaking are needed to address the growing trend of stem cell tourism in the country. CONCLUSIONS: The field of SCR is still in its infancy in Pakistan, and needs improvement; scientists, academia, policymakers, and funding agencies must come together to foster high-impact stem cell research in the country. This will aid in elevating the economic burden of many incurable diseases in the country. The outcomes of this study will be helpful for policymakers in their decision-making process.
Assuntos
Médicos , Pesquisa com Células-Tronco , Humanos , Paquistão , Governo , TraduçõesRESUMO
BACKGROUND: Acute promyelocytic leukemia (APL) is a subset of acute myeloid leukemia (AML) which is characterized by the fusion of promyelocytic leukemia PML and retinoic acid receptor- alpha (RAR-alpha) genes. All-trans retinoic acid (ATRA) and/or arsenic trioxide (ATO) have resulted in durable cytogenetic and molecular remissions in most APL patients and have altered the natural history of the disease. Most APL patients treated with ATRA and/or ATO are now anticipated to have a nearly normal life expectancy. Unfortunately, relapse and resistance to the current treatment occur in APL patients and the outcome remains dismal in these refractory patients. AXL receptor tyrosine kinase (AXL-RTK) has been shown to increase tumour burden, provide resistance to therapy and is critical to maintain cancer stem cells (CSCs) in chronic myeloid leukemia (CML) by stabilizing ß-catenin in the Wnt/ß-catenin signalling pathway. However, the role of AXL-RTK has not been explored in PML/RARα-positive APL. This study aimed to explore the role of AXL-RTK receptor in PML/RARα-positive APL. METHODS AND RESULTS: By using biochemical and pharmacological approaches, here we report that targeting of AXL-RTK is related to the down-regulation of ß-catenin target genes including c-myc (p < 0.001), AXIN2 (p < 0.001), and HIF1α (p < 0.01) and induction of apoptosis in PML/RARα-positive APL cell line. Resistance to all-trans retinoic acid (ATRA) was also overcomed by targeting AXL-RTK with R428 in APL (p < 0.05). CONCLUSION: Our results provide clear evidence of the involvement of AXL-RTK in leukemogenic potential of PML/RARα-positive APL and suggest targeting of AXL-RTK in the treatment of therapy resistant APL patients.
Assuntos
Leucemia Promielocítica Aguda/terapia , Proteínas Proto-Oncogênicas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Apoptose , Linhagem Celular Tumoral , Humanos , Receptor Tirosina Quinase AxlRESUMO
Resistance remains the major clinical challenge for the therapy of Philadelphia chromosome-positive (Ph+) leukemia. With the exception of ponatinib, all approved tyrosine kinase inhibitors (TKIs) are unable to inhibit the common "gatekeeper" mutation T315I. Here we investigated the therapeutic potential of crizotinib, a TKI approved for targeting ALK and ROS1 in non-small cell lung cancer patients, which inhibited also the ABL1 kinase in cell-free systems, for the treatment of advanced and therapy-resistant Ph+ leukemia. By inhibiting the BCR-ABL1 kinase, crizotinib efficiently suppressed growth of Ph+ cells without affecting growth of Ph- cells. It was also active in Ph+ patient-derived long-term cultures (PD-LTCs) independently of the responsiveness/resistance to other TKIs. The efficacy of crizotinib was confirmed in vivo in syngeneic mouse models of BCR-ABL1- or BCR-ABL1T315I-driven chronic myeloid leukemia-like disease and in BCR-ABL1-driven acute lymphoblastic leukemia (ALL). Although crizotinib binds to the ATP-binding site, it also allosterically affected the myristol binding pocket, the binding site of GNF2 and asciminib (former ABL001). Therefore, crizotinib has a seemingly unique double mechanism of action, on the ATP-binding site and on the myristoylation binding pocket. These findings strongly suggest the clinical evaluation of crizotinib for the treatment of advanced and therapy-resistant Ph+ leukemia.
Assuntos
Antineoplásicos/farmacologia , Crizotinibe/farmacologia , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Trifosfato de Adenosina/metabolismo , Regulação Alostérica/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos , Proteínas de Fusão bcr-abl/genética , Proteínas de Fusão bcr-abl/metabolismo , Humanos , Células Jurkat , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Camundongos , Mutação/efeitos dos fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-abl/metabolismoRESUMO
Adoptive transfer of T cells genetically modified to express a cancer-specific T-cell receptor (TCR) has shown significant therapeutic potential for both hematological and solid tumors. However, a major issue of transducing T cells with a transgenic TCR is the preexisting expression of TCRs in the recipient cells. These endogenous TCRs compete with the transgenic TCR for surface expression and allow mixed dimer formation. Mixed dimers, formed by mispairing between the endogenous and transgenic TCRs, may harbor autoreactive specificities. To circumvent these problems, we designed a system where the endogenous TCR-ß is knocked out from the recipient cells using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 (Cas9) technology, simultaneously with transduction with a cancer-reactive receptor of choice. This TCR replacement strategy resulted in markedly increased surface expression of transgenic αß and γδ TCRs, which in turn translated to a stronger, and more polyfunctional, response of engineered T cells to their target cancer cell lines. Additionally, the TCR-plus-CRISPR-modified T cells were up to a thousandfold more sensitive to antigen than standard TCR-transduced T cells or conventional model proxy systems used for studying TCR activity. Finally, transduction with a pan-cancer-reactive γδ TCR used in conjunction with CRISPR/Cas9 knockout of the endogenous αß TCR resulted in more efficient redirection of CD4+ and CD8+ T cells against a panel of established blood cancers and primary, patient-derived B-cell acute lymphoblastic leukemia blasts compared with standard TCR transfer. Our results suggest that TCR transfer combined with genome editing could lead to new, improved generations of cancer immunotherapies.
Assuntos
Antineoplásicos/metabolismo , Sistemas CRISPR-Cas/genética , Genes Codificadores dos Receptores de Linfócitos T/genética , Linfócitos T/metabolismo , Transgenes , Proteína 9 Associada à CRISPR/metabolismo , Linhagem Celular Tumoral , Técnicas de Inativação de Genes , Células HEK293 , Neoplasias Hematológicas/imunologia , Neoplasias Hematológicas/patologia , Humanos , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Reprodutibilidade dos TestesRESUMO
The hallmark of Philadelphia chromosome positive (Ph(+)) leukemia is the BCR/ABL kinase, which is successfully targeted by selective ATP competitors. However, inhibition of BCR/ABL alone is unable to eradicate Ph(+) leukemia. The t(9;22) is a reciprocal translocation which encodes not only for the der22 (Philadelphia chromosome) related BCR/ABL, but also for der9 related ABL/BCR fusion proteins, which can be detected in 65% of patients with chronic myeloid leukemia (CML) and 100% of patients with Ph+ acute lymphatic leukemia (ALL). ABL/BCRs are oncogenes able to influence the lineage commitment of hematopoietic progenitors. Aim of this study was to further disclose the role of p96(ABL/BCR) for the pathogenesis of Ph(+) ALL. The co-expression of p96(ABL/BCR) enhanced the kinase activity and as a consequence, the transformation potential of p185(BCR/ABL). Targeting p96(ABL/BCR) by RNAi inhibited growth of Ph(+) ALL cell lines and Ph(+) ALL patient-derived long-term cultures (PD-LTCs). Our in vitro and in vivo stem cell studies further revealed a functional hierarchy of p96(ABL/BCR) and p185(BCR/AB)L in hematopoietic stem cells. Co-expression of p96(ABL/BCR) abolished the capacity of p185(BCR/ABL) to induce a CML-like disease and led to the induction of ALL. Taken together our here presented data reveal an important role of p96(ABL/BCR) for the pathogenesis of Ph(+) ALL.
Assuntos
Proteínas de Fusão bcr-abl/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Translocação Genética/genética , Linhagem Celular Tumoral , Cromossomos Humanos Par 22/genética , Cromossomos Humanos Par 9/genética , Proteínas de Fusão bcr-abl/biossíntese , Regulação Leucêmica da Expressão Gênica , Células-Tronco Hematopoéticas/patologia , Humanos , Cromossomo Filadélfia , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologiaRESUMO
Philadelphia-positive (Ph+) leukemia is a type of blood cancer also known as acute lymphoblastic leukemia (ALL), affecting 20-30% of adults diagnosed worldwide and having an engraved prognosis as compared to other types of leukemia. The current treatment regimens mainly rely on tyrosine kinase inhibitors (TKIs) and bone marrow transplants. To date, several generations of TKIs have been developed due to associated resistance and frequent relapse, with cardiovascular system anomalies being the most devastating complication. Nanotechnology has the potential to address these limitations by the targeted drug delivery and controlled release of TKIs. This study focused on the titanium dioxide (TiO2) and graphene oxide (GO) nanocomposite employment to load nilotinib and ponatinib TKIs for therapy of Ph+ leukemia cell line (K562) and Ba/F3 cells engineered to express BCR-ABL oncogene. Meanwhile, after treatment, the oncogene expressing fibroblast cells (Rat-1 P185) were evaluated for their colony formation ability under 3D conditions. To validate the nanocomposite formation, the TiO2-GO nanocomposites were characterized by scanning electron microscope, DLS, XRD, FTIR, zeta potential, EDX, and element mapping. The TKI-loaded TiO2-GO was not inferior to the free drugs after evaluating their effects by a cell viability assay (XTT), apoptosis induction, and colony formation inhibition. The cell signaling pathways of the mammalian target of rapamycin (mTOR), signal transducers and activators of transcription 5 (STAT5), and extracellular signal-regulated kinase (Erk1/2) were also investigated by Western blot. These signaling pathways were significantly downregulated in the TKI-loaded TiO2-GO-treated groups. Based on the findings above, we can conclude that TiO2-GO exhibited excellent drug delivery potential that can be used for Ph+ leukemia therapy in the future, subject to further investigations.
Assuntos
Antineoplásicos , Sobrevivência Celular , Grafite , Nanocompostos , Titânio , Grafite/química , Grafite/farmacologia , Titânio/química , Titânio/farmacologia , Nanocompostos/química , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/química , Sobrevivência Celular/efeitos dos fármacos , Teste de Materiais , Tamanho da Partícula , Ensaios de Seleção de Medicamentos Antitumorais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Proliferação de Células/efeitos dos fármacos , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , AnimaisRESUMO
BACKGROUND: The t(9;22) translocation leads to the formation of the chimeric breakpoint cluster region/c-abl oncogene 1 (BCR/ABL) fusion gene on der22, the Philadelphia chromosome. The p185(BCR/ABL) or the p210(BCR/ABL) fusion proteins are encoded as a result of the translocation, depending on whether a "minor" or "major" breakpoint occurs, respectively. Both p185(BCR/ABL) and p210(BCR/ABL) exhibit constitutively activated ABL kinase activity. Through fusion to BCR the ABL kinase in p185(BCR/ABL) and p210(BCR/ABL) "escapes" the auto-inhibition mechanisms of c-ABL, such as allosteric inhibition. A novel class of compounds including GNF-2 restores allosteric inhibition of the kinase activity and the transformation potential of BCR/ABL. Here we investigated whether there are differences between p185(BCR/ABL) and p210(BCR/ABL) regarding their sensitivity towards allosteric inhibition by GNF-2 in models of Philadelphia chromosome-positive acute lymphatic leukemia. DESIGN AND METHODS: We investigated the anti-proliferative activity of GNF-2 in different Philadelphia chromosome-positive acute lymphatic leukemia models, such as cell lines, patient-derived long-term cultures and factor-dependent lymphatic Ba/F3 cells expressing either p185(BCR/ABL) or p210(BCR/ABL) and their resistance mutants. RESULTS: The inhibitory effects of GNF-2 differed constantly between p185(BCR/ABL) and p210(BCR/ABL) expressing cells. In all three Philadelphia chromosome-positive acute lymphatic leukemia models, p210(BCR/ABL)-transformed cells were more sensitive to GNF-2 than were p185BCR/ABL-positive cells. Similar results were obtained for p185(BCR/ABL) and the p210(BCR/ABL) harboring resistance mutations. CONCLUSIONS: Our data provide the first evidence of a differential response of p185(BCR/ABL)- and p210(BCR/ABL)- transformed cells to allosteric inhibition by GNF-2, which is of importance for the treatment of patients with Philadelphia chromosome-positive acute lymphatic leukemia.
Assuntos
Proteínas de Fusão bcr-abl/antagonistas & inibidores , Leucemia Mielogênica Crônica BCR-ABL Positiva , Pirimidinas/farmacologia , Regulação Alostérica/efeitos dos fármacos , Regulação Alostérica/fisiologia , Linhagem Celular Tumoral , Proteínas de Fusão bcr-abl/genética , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Pirimidinas/uso terapêuticoRESUMO
BACKGROUND: Philadelphia positive leukemias are characterized by the presence of Bcr-Abl fusion protein which exhibits an abnormal kinase activity. Selective Abl kinase inhibitors have been successfully established for the treatment of Ph (+) leukemias. Despite high rates of clinical response, Ph (+) patients can develop resistance against these kinase inhibitors mainly due to point mutations within the Abl protein. Of special interest is the 'gatekeeper' T315I mutation, which confers complete resistance to Abl kinase inhibitors. Recently, GNF-2, Abl allosteric kinase inhibitor, was demonstrated to possess cellular activity against Bcr-Abl transformed cells. Similarly to Abl kinase inhibitors (AKIs), GNF-2 failed to inhibit activity of mutated Bcr-Abl carrying the T315I mutation. METHODS: Ba/F3 cells harboring native or T315I mutated Bcr-Abl constructs were treated with GNF-2 and AKIs. We monitored the effect of GNF-2 with AKIs on the proliferation and clonigenicity of the different Ba/F3 cells. In addition, we monitored the auto-phosphorylation activity of Bcr-Abl and JAK2 in cells treated with GNF-2 and AKIs. RESULTS: In this study, we report a cooperation between AKIs and GNF-2 in inhibiting proliferation and clonigenicity of Ba/F3 cells carrying T315I mutated Bcr-Abl. Interestingly, cooperation was most evident between Dasatinib and GNF-2. Furthermore, we showed that GNF-2 was moderately active in inhibiting the activity of JAK2 kinase, and presence of AKIs augmented GNF-2 activity. CONCLUSIONS: Our data illustrated the ability of allosteric inhibitors such as GNF-2 to cooperate with AKIs to overcome T315I mutation by Bcr-Abl-independent mechanisms, providing a possibility of enhancing AKIs efficacy and overcoming resistance in Ph+ leukemia cells.
Assuntos
Antineoplásicos/farmacologia , Proteínas de Fusão bcr-abl/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Quimioterapia Combinada/métodos , Genes abl , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Mutação/efeitos dos fármacos , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/uso terapêuticoRESUMO
BACKGROUND: Chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphatic leukemia (Ph + ALL) are caused by the t(9;22), which fuses BCR to ABL resulting in deregulated ABL-tyrosine kinase activity. The constitutively activated BCR/ABL-kinase "escapes" the auto-inhibition mechanisms of c-ABL, such as allosteric inhibition. The ABL-kinase inhibitors (AKIs) Imatinib, Nilotinib or Dasatinib, which target the ATP-binding site, are effective in Ph + leukemia. Another molecular therapy approach targeting BCR/ABL restores allosteric inhibition. Given the fact that all AKIs fail to inhibit BCR/ABL harboring the 'gatekeeper' mutation T315I, we investigated the effects of AKIs in combination with the allosteric inhibitor GNF2 in Ph + leukemia. METHODS: The efficacy of this approach on the leukemogenic potential of BCR/ABL was studied in Ba/F3 cells, primary murine bone marrow cells, and untransformed Rat-1 fibroblasts expressing BCR/ABL or BCR/ABL-T315I as well as in patient-derived long-term cultures (PDLTC) from Ph + ALL-patients. RESULTS: Here, we show that GNF-2 increased the effects of AKIs on unmutated BCR/ABL. Interestingly, the combination of Dasatinib and GNF-2 overcame resistance of BCR/ABL-T315I in all models used in a synergistic manner. CONCLUSIONS: Our observations establish a new approach for the molecular targeting of BCR/ABL and its resistant mutants using a combination of AKIs and allosteric inhibitors.
Assuntos
Proteínas de Fusão bcr-abl/antagonistas & inibidores , Proteínas de Fusão bcr-abl/genética , Mutação , Inibidores de Proteínas Quinases/farmacologia , Regulação Alostérica/efeitos dos fármacos , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Células Cultivadas , Ensaio de Unidades Formadoras de Colônias , Dasatinibe , Feminino , Expressão Gênica , Células-Tronco Hematopoéticas/metabolismo , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Camundongos , Pirimidinas/farmacologia , Tiazóis/farmacologiaRESUMO
Tyrosine kinase inhibitors (TKIs) such as imatinib, nilotinib, dasatinib, and ponatinib have significantly improved the life expectancy of Philadelphia chromosome-positive (Ph+) acute lymphocytic leukemia (ALL) patients; however, resistance to TKIs remains a major clinical challenge. Point mutations in the tyrosine kinase domain (TKD) of BCR-ABL1 have emerged as the predominant cause of acquired resistance. In approximately 30% of patients, the mechanism of resistance to TKIs remains elusive. This study aimed to investigate mechanisms of nonmutational resistance in Ph+ ALL. Here we report the development of a nonmutational resistance cell line SupB15-RT; conferring resistance to approved ABL kinase inhibitors (AKIs) and allosteric inhibitors GNF-2, ABL001, and crizotinib, except for dasatinib (IC90 50nM), a multitarget kinase inhibitor. We found that the AKT/mTOR pathway is activated in these cells and their proliferation inhibited by Torin-1 with an IC50 of 24.7 nM. These observations were confirmed using 3 different ALL patient-derived long term cultures (PDLTCs): (1) HP (BCR-ABL1 negative), (2) PH (BCR-ABL1 positive and responsive to TKIs) and (3) BV (BCR-ABL1 positive and nonmutational resistant to TKIs). Furthermore, Torin-1 and NVP-BEZ235 induced apoptosis in PH and BV cells but not in HP cells. Our experiments provide evidence of the involvement of AKT/mTOR pathway in the evolution of nonmutational resistance in Ph+ ALL which will assist in developing novel targeted therapy for Ph+ ALL patients with BCR-ABL1 independent nonmutational resistance.
Assuntos
Resistencia a Medicamentos Antineoplásicos/fisiologia , Oncogenes/fisiologia , Cromossomo Filadélfia , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Relação Dose-Resposta a Droga , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Humanos , Células Jurkat , Inibidores de MTOR/farmacologia , Inibidores de MTOR/uso terapêutico , Oncogenes/efeitos dos fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogênicas c-akt/genética , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/genética , Células Tumorais CultivadasRESUMO
The BCR/ABL oncogene is responsible for the phenotype of Philadelphia chromosome-positive (Ph+) leukemia. BCR/ABL exhibits an aberrant ABL-tyrosine kinase activity. The treatment of advanced Ph+ leukemia with selective ABL-kinase inhibitors such as Imatinib, Nilotinib and Dasatinib is initially effective but rapidly followed by resistance mainly because of specific mutations in BCR/ABL. Tetramerization of ABL through the N-terminal coiled-coil region (CC) of BCR is essential for the ABL-kinase activation. Targeting the CC-domain forces BCR/ABL into a monomeric conformation reduces its kinase activity and increases the sensitivity for Imatinib. We show that (i) targeting the tetramerization by a peptide representing the Helix-2 of the CC efficiently reduced the autophosphorylation of both unmutated and mutated BCR/ABL; (ii) Helix-2 inhibited the transformation potential of BCR/ABL independently of the presence of mutations; and (iii) Helix-2 efficiently cooperated with Imatinib as revealed by their effects on the transformation potential and the factor-independence related to BCR/ABL with the exception of mutant T315I. These findings support earlier observations that BCR/ABL harboring the T315I mutation have a transformation potential that is at least partially independent of its kinase activity. These data provide evidence that the inhibition of tetramerization inhibits BCR/ABL-mediated transformation and can contribute to overcome Imatinib-resistance.
Assuntos
Antineoplásicos/farmacologia , Biopolímeros/química , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Mutação , Piperazinas/farmacologia , Pirimidinas/farmacologia , Sequência de Bases , Benzamidas , Linhagem Celular , Primers do DNA , Proteínas de Fusão bcr-abl/genética , Humanos , Mesilato de Imatinib , Mutagênese Sítio-Dirigida , FosforilaçãoRESUMO
Himalayan gray goral is endemic to Himalayas and Hindukush ranges. Analysis of 15 fecal samples and field observations from different areas of Pakistan and Azad Kashmir suggest that goral consumes foliage of a minimum of 28 plant species. Trees, shrubs and grasses appear in the ratio of 1:36:63 and hence the species is a grazer, though may opt for browsing when forced. The species mainly subsists on six species of grasses (Chrysopogon aucheri=17.97%, Themeda anathera=13.03%, Poa pratensis=11.23%, Digitaria decumbens=9.30%, Apluda mutica=7.51%, Aristida cyanatha=3.15%), though leaves of shrubs (Myrsine africana=11.38%, Daphne oleoides=8.87%, Carissa opaca=5.94%, Dodonaea viscose=4.79%, Rubus ellipticus=2.93%, Gymnosporia royleana=1.29%) are also consumed. Food preference indices (consumed/availability) suggest that grasses are highly preferred (16.86 times of availability), followed by shrubs (3.3 times of availability), whereas trees and herbs are not preferred. Food plants contain water (77.9+/-0.56%), ash (8.6+/-0.38%), sugars (6.8+/-0.16%), proteins (5.6%+/-0.28%) and fats (1.3+/-0.08%). Food provides 4,440 kcal of energy and 5.45 L of water/day/adult goral, which is sufficient to meet the requirements of the species. Grasses need to be ensured in the protected area separated for management of goral population. Zoo Biol 27:371-380, 2008. (c) 2008 Wiley-Liss, Inc.
RESUMO
Targeting BCR/ABL with Tyrosine kinase inhibitors (TKIs) is a proven concept for the treatment of Philadelphia chromosome-positive (Ph+) leukemias but the "gatekeeper" mutation T315I confers resistance against all approved TKIs, with the only exception of ponatinib, a multi-targeted kinase inhibitor. Besides resistance to TKIs, T315I also confers additional features to the leukemogenic potential of BCR/ABL, involving endogenous BCR. Therefore we studied the role of BCR on BCR/ABL mutants lacking functional domains indispensable for the oncogenic activity of BCR/ABL. We used the factor independent growth of murine myeloid progenitor 32D cells and the transformation of Rat-1 fibroblasts both mediated by BCR/ABL. Here we report that T315I restores the capacity to mediate factor-independent growth and transformation potential of loss-of-function mutants of BCR/ABL. Targeting endogenous Bcr abrogated the capacity of oligomerization deficient mutant of BCR/ABL-T315I to mediate factor independent growth of 32D cells and strongly reduced their transformation potential in Rat-1 cells, as well as led to the up-regulation of mitogen activated protein kinase (MAPK) pathway. Our data show that the T315I restores the capacity of loss-of-function mutants to transform cells which is dependent on the transphosphorylation of endogenous Bcr, which becomes a putative therapeutic target to overcome resistance by T315I.
RESUMO
Acute myeloid leukemia (AML) is characterized by an aberrant self-renewal of hematopoietic stem cells (HSC) and a block in differentiation. The major therapeutic challenge is the characterization of the leukemic stem cell as a target for the eradication of the disease. Until now the biology of AML-associated fusion proteins (AAFPs), such as the t(15;17)-PML/RARα, t(8;21)-RUNX1/RUNX1T1 and t(6;9)-DEK/NUP214, all able to induce AML in mice, was investigated in different models and genetic backgrounds, not directly comparable to each other. To avoid the bias of different techniques and models we expressed these three AML-inducing oncogenes in an identical genetic background and compared their influence on the HSC compartment in vitro and in vivo. These AAFPs exerted differential effects on HSCs and PML/RARα, similar to DEK/NUP214, induced a leukemic phenotype from a small subpopulation of HSCs with a surface marker pattern of long-term HSC and characterized by activated STAT3 and 5. In contrast the established AML occurred from mature populations in the bone marrow. The activation of STAT5 by PML/RARα and DEK/NUP214 was confirmed in t(15;17)(PML/RARα) and t(6;9)(DEK/NUP214)-positive patients as compared to normal CD34+ cells. The activation of STAT5 was reduced upon the exposure to Arsenic which was accompanied by apoptosis in both PML/RARα- and DEK/NUP214-positive leukemic cells. These findings indicate that in AML the activation of STATs plays a decisive role in the biology of the leukemic stem cell. Furthermore we establish exposure to arsenic as a novel concept for the treatment of this high risk t(6;9)-positive AML.
Assuntos
Carcinogênese/genética , Proteínas de Fusão bcr-abl/genética , Monoéster Fosfórico Hidrolases/genética , Proteínas Tirosina Fosfatases/genética , Animais , Linhagem Celular , Células HEK293 , Humanos , Mesilato de Imatinib/farmacologia , Camundongos , Fosforilação/efeitos dos fármacos , Fosforilação/genéticaRESUMO
This research study evaluated the effect of different additives on the bait consumption by Indian crested porcupine, a serious forest and agricultural pest, under field conditions. Different additives (saccharin, common salt, bone meal, fish meal, peanut butter, egg yolk, egg shell powder, yeast powder, mineral oil and coconut oil) at 2 and 5% each were tested for their relative preference, using groundnut-maize (1:1) as basic bait. All the additives were tested under a no-choice test pattern. For control tests, no additive was mixed with the basic bait. Saccharin at 5% concentration significantly enhanced the consumption of bait over the basic bait, while 2% saccharin supplemented bait resulted in a non-significant bait consumption. All other additives did not enhance the consumption of the bait material; rather, these worked as repellents. However, the repellency was lowest with the common salt, followed by egg yolk, egg shell powder, bone meal, peanut butter, mineral oil, fish meal and yeast powder, while coconut remained the most repellent compound. The present study suggested that groundnut-maize (1:1) supplemented with 5% saccharin was the preferred bait combination, and can be used with different rodenticides for the management of Indian crested porcupine.
Assuntos
Preferências Alimentares/fisiologia , Porcos-Espinhos/fisiologia , Controle de Roedores/métodos , Sacarina , Animais , Nozes , Paquistão , Rodenticidas , Zea maysAssuntos
Infecções por Citomegalovirus/epidemiologia , Herpes Simples/epidemiologia , Complicações Infecciosas na Gravidez/epidemiologia , Rubéola (Sarampo Alemão)/epidemiologia , Coinfecção/epidemiologia , Feminino , Humanos , Recém-Nascido , Paquistão/epidemiologia , Projetos Piloto , Gravidez , Gestantes , Estudos SoroepidemiológicosRESUMO
Iron oxide nanoparticles (IONPs) synthesized via thermal decomposition find diverse applications in biomedicine owing to precise control of their physico-chemical properties. However, use in such applications requires phase transfer from organic solvent to water, which remains a bottleneck. Through the thermal decomposition of iron oleate (FeOl), we systematically investigate the impact of synthesis conditions such as oleic acid (OA) amount, temperature increase rate, dwell time, and solvent on the size, magnetic saturation, and crystallinity of IONPs. Solvent choice significantly influences these properties, manipulating which, synthesis of monodisperse IONPs within a tunable size range (10-30 nm) and magnetic properties (75 to 42 Am2Kg-1) is obtained. To enable phase transfer of IONPs, we employ flash nanoprecipitation (FNP) for the first time as a method for scalable and precise size control, demonstrating its potential over conventional methods. Poly(lactic-co-glycolic acid) (PLGA)-coated IONPs with hydrodynamic diameter (Hd) in the range of 250 nm, high colloidal stability and high IONPs loadings up to 43% were obtained, such physicochemical properties being tuned exclusively by the size and hydrophobicity of starting IONPs. They showed no discernible cytotoxicity in human dermal fibroblasts, highlighting the applicability of FNP as a novel method for the functionalization of hydrophobic IONPs for biomedicine.