Philadelphia chromosome-positive leukemia stem cells in acute lymphoblastic leukemia and tyrosine kinase inhibitor therapy

Leukemia stem cells(LSCs),which constitute a minority of the tumor bulk,are functionally defined on the basis of their ability to transfer leukemia into an immunodeficient recipient animal.The presence of LSCs has been demonstrated in acute lymphoblastic leukemia(ALL),of which ALL with Philadelphia chromosome-positive(Ph+).The use of imatinib,a tyrosine kinase inhibitor(TKI),as part of front-line treatment and in combination with cytotoxic agents,has greatly improved the proportions of complete response and molecular remission and the overall outcome in adults with newly diagnosed Ph+ ALL.New challenges have emerged with respect to induction of resistance to imatinib via Abelson tyrosine kinase mutations.An important recent addition to the arsenal against Ph+ leukemias in general was the development of novel TKIs,such as nilotinib and dasatinib.However,in vitro experiments have suggested that TKIs have an antiproliferative but not an antiapoptotic or cytotoxic effect on the most primitive ALL stem cells.None of the TKIs in clinical use target the LSC.Second generation TKI dasatinib has been shown to have a more profound effect on the stem cell compartment but the drug was still unable to kill the most primitive LSCs.Allogeneic stem cell transplantation(SCT) remains the only curative treatment available for these patients.Several mechanisms were proposed to explain the resistance of LSCs to TKIs in addition to mutations.Hence,TKIs may be used as a bridge to SCT rather than monotherapy or combination with standard chemotherapy.Better understanding the biology of Ph+ ALL will open new avenues for effective management.In this review,we highlight recent findings relating to the question of LSCs in Ph+ ALL.     

Requirement for NK cells in CD40 ligand-mediated rejection of Philadelphia chromosome-positive acute lymphoblastic leukemia cells.

We have previously developed a murine model of Philadelphia chromosome-positive acute lymphoblastic leukemia by i.v. injection of a pre-B ALL cell line (BM185) derived from Bcr-Abl-transformed BALB/c bone marrow. We are studying the potential to elicit autologous antileukemic immune responses by introducing genes encoding immunomodulators (CD40 ligand (CD40L), CD80, and GM-CSF) into leukemia cells. BM185 cells expressing CD40L or CD80 alone, when injected into BALB/c mice, were rejected in approximately 25% of mice, whereas cohorts receiving BM185 cells expressing two or more immunomodulator genes rejected challenge 50-76% of the time. The greatest protection was conferred in mice receiving BM185 cells expressing all three immunomodulators. Addition of murine rIL-12 treatments in conjunction with BM185/CD80/CD40L/GM-CSF vaccination allowed rejection of preestablished leukemia. BM185 cell lines expressing CD40L were rejected in BALB/c nu/nu (nude) mice, in contrast to cell lines expressing CD80 and/or GM-CSF. Nude mice depleted of NK cells were no longer protected when challenged with BM185/CD40L, demonstrating a requirement for NK cells. Similarly, NK cell depletion in immunocompetent BALB/c mice resulted in a loss of protection when challenged with BM185/CD40L, confirming the data seen in nude mice. The ability of CD40L to act in a T cell-independent manner may be important for clinical applications in patients with depressed cellular immunity following chemotherapy.     

Oncoproteomics: current trends and future perspectives

Oncoproteomics is the application of proteomics technologies in oncology. Functional proteomics is a promising technique for the rational identification of biomarkers and novel therapeutic targets for cancers. Recent progress in proteomics has opened new avenues for tumor-associated biomarker discovery. With the advent of new and improved proteomics technologies, such as the development of quantitative proteomic methods, high-resolution, -speed and -sensitivity mass spectrometry and protein arrays, as well as advanced bioinformatics for data handling and interpretation, it is now possible to discover biomarkers that can reliably and accurately predict outcomes during cancer management and treatment. However, there are several difficulties in the study of proteins/peptides that are not inherent in the study of nucleic acids. New challenges arise in large-scale proteomic profiling when dealing with complex biological mixtures. Nevertheless, oncoproteomics offers great promise for unveiling the complex molecular events of tumorigenesis, as well as those that control clinically important tumor behaviors, such as metastasis, invasion and resistance to therapy. In this review, the development and advancement of oncoproteomics technologies for cancer research in recent years are expounded.     

Oncoproteomics: current trends and future perspectives

Oncoproteomics is the application of proteomics technologies in oncology. Functional proteomics is a promising technique for the rational identification of biomarkers and novel therapeutic targets for cancers. Recent progress in proteomics has opened new avenues for tumor-associated biomarker discovery. With the advent of new and improved proteomics technologies, such as the development of quantitative proteomic methods, high-resolution, -speed and -sensitivity mass spectrometry and protein arrays, as well as advanced bioinformatics for data handling and interpretation, it is now possible to discover biomarkers that can reliably and accurately predict outcomes during cancer management and treatment. However, there are several difficulties in the study of proteins/peptides that are not inherent in the study of nucleic acids. New challenges arise in large-scale proteomic profiling when dealing with complex biological mixtures. Nevertheless, oncoproteomics offers great promise for unveiling the complex molecular events of tumorigenesis, as well as those that control clinically important tumor behaviors, such as metastasis, invasion and resistance to therapy. In this review, the development and advancement of oncoproteomics technologies for cancer research in recent years are expounded.     

Super-SILAC: current trends and future perspectives

Stable isotope labeling with amino acids in cell culture (SILAC) has risen as a powerful quantification technique in mass spectrometry (MS)–based proteomics in classical and modified forms. Previously, SILAC was limited to cultured cells because of the requirement of active protein synthesis; however, in recent years, it was expanded to model organisms and tissue samples. Specifically, the super-SILAC technique uses a mixture of SILAC-labeled cells as a spike-in standard for accurate quantification of unlabeled samples, thereby enabling quantification of human tissue samples. Here, we highlight the recent developments in super-SILAC and its application to the study of clinical samples, secretomes, post-translational modifications and organelle proteomes. Finally, we propose super-SILAC as a robust and accurate method that can be commercialized and applied to basic and clinical research.     

Space biotechnology: current and future perspectives

The potential for obtaining enhanced purities and for achieving greater homogeneity of materials in microgravity first attracted biotechnologists to space bioprocessing. This is but one of the benefits of microgravity. This review discusses the unique opportunities of space biotechnology and the diverse means to achieve microgravity conditions.     

Cancer metabolism: current perspectives and future directions

Cellular metabolism influences life and death decisions. An emerging theme in cancer biology is that metabolic regulation is intricately linked to cancer progression. In part, this is due to the fact that proliferation is tightly regulated by availability of nutrients. Mitogenic signals promote nutrient uptake and synthesis of DNA, RNA, proteins and lipids. Therefore, it seems straight-forward that oncogenes, that often promote proliferation, also promote metabolic changes. In this review we summarize our current understanding of how ‘metabolic transformation'' is linked to oncogenic transformation, and why inhibition of metabolism may prove a cancer′s ‘Achilles'' heel''. On one hand, mutation of metabolic enzymes and metabolic stress sensors confers synthetic lethality with inhibitors of metabolism. On the other hand, hyperactivation of oncogenic pathways makes tumors more susceptible to metabolic inhibition. Conversely, an adequate nutrient supply and active metabolism regulates Bcl-2 family proteins and inhibits susceptibility to apoptosis. Here, we provide an overview of the metabolic pathways that represent anti-cancer targets and the cell death pathways engaged by metabolic inhibitors. Additionally, we will detail the similarities between metabolism of cancer cells and metabolism of proliferating cells.     

Wound degradomics - current status and future perspectives

Proteases are pivotal modulators of extracellular matrix components and bioactive proteins at all phases of cutaneous wound healing and thereby essentially contribute to the successful reestablishment of skin integrity upon injury. As a consequence, disturbance of proteolytic activity at the wound site is a major factor in the pathology of chronic wounds. A large body of data acquired in many years of research provide a good understanding of how individual proteases may influence the repair process. The next challenge will be to integrate these findings and to elucidate the complex interactions of proteolytic enzymes, their inhibitors and substrates on a system-wide level. Here, we present novel approaches that might help to achieve this ambitious goal in cutaneous wound healing research.     

Cellular fatty acid-binding proteins: current concepts and future directions

Summary At least three different proteins are implicated in the cellular transport of fatty acid moieties: a plasmalemmal membrane and a cytoplasmic fatty acid-binding protein (FABP_PM and FABP_C, respectively) and cytoplasmic acyl-CoA binding protein (ACBP). Their putative main physiological significance is the assurance that long-chain fatty acids and derivatives, either in transit through membranes or present in intracellular compartments, are largely complexed to proteins. FABP_C distinguishes from the other proteins in that distinct types of FABP_C are found in remarkable abundance in the cytoplasmic compartment of a variety of tissues. Although their mechanism of action is not yet fully elucidated, current knowledge suggests that the function of this set of proteins reaches beyond simply aiding cytoplasmic solubilization of hydrophobic ligands, but that they can be assigned several regulatory roles in cellular lipid homeostasis.     

Enatiomerically pure hydroxycarboxylic acids: current approaches and future perspectives

The growing awareness of the importance of chirality in conjunction with biological activity has led to an increasing demand for efficient methods for the industrial synthesis of enantiomerically pure compounds. Polyhydroxyalkanotes (PHAs) are a family of polyesters consisting of over 140 chiral R-hydroxycarboxylic acids (R-HAs), representing a promising source for obtaining chiral chemicals from renewable carbon sources. Although some R-HAs have been produced for some time and certain knowledge of the production processes has been gained, large-scale production has not yet been possible. In this article, through analysis of the current advances in production of these acids, we present guidelines for future developments in biotechnological processes for R-HA production.     

工业生物发酵过程模拟：进展与发展趋势

工业生物发酵是工业生物技术规模化生产必需的基本操作单元。对微生物细胞及其反应器进行数学模拟将有助于加深对发酵过程的理解,也将为新的合成生物构建提供解决策略。文中对工业发酵系统的特点、数学模拟的发展历史、数学模型的分类和特点、用途等作了深入阐述,并展望了全发酵系统模拟的发展趋势。     

Feruloyl Esterases as Biotechnological Tools： Current and Future Perspectives

Feruloyl esterases represent a diverse group of hydrolases catalyzing the cleavage and formation of ester bonds between plant cell wall polysaccharide and phenolic acid. They are widely distributed in plants and microorganisms. Besides lipases, a considerable number of microbial feruloyl esterases have also been discovered and overexpressed. This review summarizes the latest research on their classification, production, and biophysicochemical properties. Special emphasis is given to the importance of that type of enzyme and their related phenolic ferulic acid compound in biotechnological processes, and industrial and medicinal applications.     

Microbial lipolytic fusion enzymes: current state and future perspectives

Genetic fusion of coding ORFs or connection of proteins in a post translational process are rather novel techniques to build products called fusion proteins that possess combined characteristics of their parental biomolecules. This attractive strategy used to create new enzymes not only diversifies their functionality by improving thermostability, thermo- and catalytic activity, substrate specificity, regio- or enantio-selectivity but also facilitates their purification and increases their yield. Many examples of microbial synthetic fusion biocatalysts are associated with fused enzymes that are involved in biomass degradation. However, one of the leading production segments is occupied by microbial lipolytic enzymes (lipases and esterases). As powerful biocatalysts these enzymes found their application in detergent, food, oil and fat, pulp and paper, leather, textile, cosmetics, biodiesel production industries. Moreover, lipolytic enzymes market is predicted to maintain leadership up to the year of 2024 and exceed millions of dollars. Recently, creation of lipolytic fusion biocatalysts for industrial applications gained more attention since it is not only a way of achievement of enzymes with improved properties but also a way to reduce industrial energy costs and ensure other economic benefits. This paper provides a comprehensive review on current state of microbial lipolytic fusion enzymes and their future potential.     

Bioaugmentation in activated sludge: current features and future perspectives

Bioaugmentation of activated sludge systems with specialised bacterial strains could be a powerful tool to improve several aspects in wastewater treatment processes, such as improved flocculation and degradation of recalcitrant compounds. This review focuses on the addition of strains to activated sludge to enhance the biodegradation of recalcitrant compounds, either through the activity of the inoculated strain or after transfer of degradative plasmids to activated sludge bacteria. Different factors that improve the aggregation of the sludge flocs and their influence on biodegradation are described. This review further deals with the role of bacterial plasmids in natural genetic exchange between inoculated and indigenous sludge bacteria, and in the construction of new genetically modified organisms. The few successful cases of bioaugmentation described in this review, together with future research, must lead to a better understanding of sludge bioaugmentation. Received: 5 January 1998 / Received revision: 20 April 1998 / Accepted: 20 April 1998     

Polymers for gene delivery: current status and future perspectives

Gene therapy is a hope for curing many diseases and pathological conditions which are relatively difficult to treat. However lack of proper gene delivery vehicle is the main limiting step in this direction. Though viral vectors still lead as the major vehicle used in gene therapy clinical trials, their immunogenicity and low capacity restrict their wide use. Hence there is a need for developing non-viral vectors which can really be used for clinical applications. Polymers are a versatile group of molecules which can be modified and designed or engineered according to the end needs of the applications. The objective of this review is to summarize the recent advances in the development of polymeric vectors for gene delivery applications reported in patents and scientific journals.     

Molecular biology of Philadelphia chromosome in chronic granulocytic leukaemia and acute lymphoblastic leukaemia

In classical t(9;22) translocation, as observed in chronic granulocytic leukemia (CGL), a hybrid DNA unit is produced, including a rearranged PHL gene, previously known as bcr (breakpoint cluster region) plus the translocated c-abl gene from chromosome 9: a hybrid bcr-abl protein, p210 is formed, with increased tyrosine kinase activity. Such DNA rearrangement, with a p210 protein synthesis, is also found in cases of Philadelphia-positive acute lymphoblastic leukemia (ALL), but in apparently similar cases the bcr gene is not rearranged, and a novel p190 abl-related protein can be found; c-abl rearrangement has also been observed.It is thus established that correlations between cytogenetic and molecular events can be found in CGL and ALL, as in other haemopoietic malignancies: translocation and possible rearrangement of the c-abl oncogene seem of particular importance in this case.     

Overcoming minimal residual disease using intensified conditioning with medium-dose etoposide,cyclophosphamide and total body irradiation in allogeneic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia in adults

Background aimsAn intensified conditioning regimen incorporating medium-dose etoposide (VP16) is an option for patients with acute lymphoblastic leukemia (ALL). However, the prognostic impacts of the addition of VP16 to cyclophosphamide (CY) and total body irradiation (TBI) in patients with Philadelphia chromosome-positive (Ph+) ALL with regard to minimal residual disease (MRD) status have not been elucidated.MethodsThe authors retrospectively compared the outcomes of patients with Ph+ ALL who underwent allogeneic transplantation following VP16/CY/TBI (n = 101) and CY/TBI (n = 563).ResultsAt 4 years, the VP16/CY/TBI group exhibited significantly better disease-free survival (DFS) (72.6% versus 61.7%, P = 0.027) and relapse rate (11.5% versus 21.1%, P = 0.020) and similar non-relapse mortality (16.0% versus 17.2%, P = 0.70). In subgroup analyses, the beneficial effects of the addition of VP16 on DFS were more evident in patients with positive MRD status (71.2% versus 48.4% at 4 years, P = 0.022) than those with negative MRD status (72.8% versus 66.7% at 4 years, P = 0.24). Although MRD positivity was significantly associated with worse DFS in patients who received CY/TBI (48.4% versus 66.7%, P < 0.001), this was not the case in those who received VP16/CY/TBI (71.2% versus 72.8%, P = 0.86).ConclusionsThis study demonstrated the benefits of the addition of VP16 in Ph+ ALL patients, especially those with positive MRD status. VP16/CY/TBI could be a potential strategy to overcome the survival risk of MRD positivity.