CD40L induces proliferation, self-renewal, rescue from apoptosis, and production of cytokines by CD40-expressing AML blasts

Inflammatory recruitment of healthy hematopoietic stem and progenitor cells in the acute myeloid leukemia niche

Inflammation in the bone marrow (BM) microenvironment is a constitutive component of leukemogenesis in acute myeloid leukemia (AML). Current evidence suggests that both leukemic blasts and stroma secrete proinflammatory factors that actively suppress the function of healthy hematopoietic stem and progenitor cells (HSPCs). HSPCs are also cellular components of the innate immune system, and we reasoned that they may actively propagate the inflammation in the leukemic niche. In two separate congenic models of AML we confirm by evaluation of the BM plasma secretome and HSPC-selective single-cell RNA sequencing (scRNA-Seq) that multipotent progenitors and long-lived stem cells adopt inflammatory gene expression programs, even at low leukemic infiltration of the BM. In particular, we observe interferon gamma (IFN-γ) pathway activation, along with secretion of its chemokine target, CXCL10. We show that AML-derived nanometer-sized extracellular vesicles (EVAML) are sufficient to trigger this inflammatory HSPC response, both in vitro and in vivo. Altogether, our studies indicate that HSPCs are an unrecognized component of the inflammatory adaptation of the BM by leukemic cells. The pro-inflammatory conversion and long-lived presence of HSPCs in the BM along with their regenerative re-expansion during remission may impact clonal selection and disease evolution.

The role of bone marrow microenvironment (BMM) cells in acute myeloid leukemia (AML) progression: immune checkpoints, metabolic checkpoints, and signaling pathways

Acute myeloid leukemia (AML) comprises a multifarious and heterogeneous array of illnesses characterized by the anomalous proliferation of myeloid cells in the bone marrow microenvironment (BMM). The BMM plays a pivotal role in promoting AML progression, angiogenesis, and metastasis. The immune checkpoints (ICs) and metabolic processes are the key players in this process. In this review, we delineate the metabolic and immune checkpoint characteristics of the AML BMM, with a focus on the roles of BMM cells e.g. tumor-associated macrophages, natural killer cells, dendritic cells, metabolic profiles and related signaling pathways. We also discuss the signaling pathways stimulated in AML cells by BMM factors that lead to AML progression. We then delve into the roles of immune checkpoints in AML angiogenesis, metastasis, and cell proliferation, including co-stimulatory and inhibitory ICs. Lastly, we discuss the potential therapeutic approaches and future directions for AML treatment, emphasizing the potential of targeting metabolic and immune checkpoints in AML BMM as prognostic and therapeutic targets. In conclusion, the modulation of these processes through the use of directed drugs opens up new promising avenues in combating AML. Thereby, a comprehensive elucidation of the significance of these AML BMM cells' metabolic and immune checkpoints and signaling pathways on leukemic cells can be undertaken in the future investigations. Additionally, these checkpoints and cells should be considered plausible multi-targeted therapies for AML in combination with other conventional treatments in AML. Video Abstract.

CAR-T Cell Therapy in Hematological Malignancies: Current Opportunities and Challenges

Chimeric antigen receptor T (CAR-T) cell therapy represents a major breakthrough in cancer treatment, and it has achieved unprecedented success in hematological malignancies, especially in relapsed/refractory (R/R) B cell malignancies. At present, CD19 and BCMA are the most common targets in CAR-T cell therapy, and numerous novel therapeutic targets are being explored. However, the adverse events related to CAR-T cell therapy might be serious or even life-threatening, such as cytokine release syndrome (CRS), CAR-T-cell-related encephalopathy syndrome (CRES), infections, cytopenia, and CRS-related coagulopathy. In addition, due to antigen escape, the limited CAR-T cell persistence, and immunosuppressive tumor microenvironment, a considerable proportion of patients relapse after CAR-T cell therapy. Thus, in this review, we focus on the progress and challenges of CAR-T cell therapy in hematological malignancies, such as attractive therapeutic targets, CAR-T related toxicities, and resistance to CAR-T cell therapy, and provide some practical recommendations.

Inflammatory response mediates cross-talk with immune function and reveals clinical features in acute myeloid leukemia

Accumulated genetic mutations are an important cause for the development of acute myeloid leukemia (AML), but abnormal changes in the inflammatory microenvironment also have regulatory effects on AML. Exploring the relationship between inflammatory response and pathological features of AML has implications for clinical diagnosis, treatment and prognosis evaluation. We analyzed the expression variation landscape of inflammatory response-related genes (IRRGs) and calculated an inflammatory response score for each sample using the gene set variation analysis (GSVA) algorithm. The differences in clinical- and immune-related characteristics between high- and low-inflammatory response groups were further analyzed. We found that most IRRGs were highly expressed in AML samples, and patients with high inflammatory response had poor prognosis and were accompanied with highly activated chemokine-, cytokine- and adhesion molecule-related signaling pathways, higher infiltration ratios of monocytes, neutrophils and M2 macrophages, high activity of type I/II interferon (IFN) response, and higher expression of immune checkpoints. We also used the Genomics of Drug Sensitivity in Cancer (GDSC) database to predict the sensitivity of AML samples with different inflammatory responses to common drugs, and found that AML samples with low inflammatory response were more sensitive to cytarabine, doxorubicin and midostaurin. SubMap algorithm also demonstrated that high-inflammatory response patients are more suitable for anti-PD-1 immunotherapy. Finally, we constructed a prognostic risk score model to predict the overall survival (OS) of AML patients. Patients with higher risk score had significantly shorter OS, which was confirmed in two validation cohorts. The analysis of inflammatory response patterns can help us better understand the differences in tumor microenvironment (TME) of AML patients, and guide clinical medication and prognosis prediction.

Raised CD40L expression attenuates drug resistance in Adriamycin-resistant THP-1 cells

Acute myeloid leukemia is a common hematological malignancy that often exhibits strong drug resistance when treated using conventional chemotherapy. Although numerous studies have been carried out to develop methods of overcoming drug resistance, the results have generally been unsatisfactory. CD40 ligand (CD40L) has been shown to improve the sensitivity of cancer cells to drug treatment. In the present study, Adriamycin (ADM)-resistant human monocytic THP-1 cells (THP-1/A cells) were developed by incubating THP-1 cells with increasing concentrations of ADM. Cells were transfected with CD40L vectors to explore the potential involvement of CD40L in regulating multidrug resistance (MDR) in cancer. Cell proliferation and viability were measured using the Cell Counting Kit-8 assay; cell apoptosis was evaluated by flow cytometry, trypan blue staining and caspase-3 activity; and the expression of MDR-associated protein 1 (MRP1) and permeability glycoprotein (P-gp) was analyzed using western blotting. The results revealed that the protein expression levels of MRP1 and P-gp were downregulated by raised CD40L expression and that the combination of raised CD40L expression with daunorubicin (DNR), a drug from which ADM is derived, significantly increased the extent of cell apoptosis, indicating that drug resistance was effectively attenuated by CD40L. Collectively, these results suggested that CD40L may contribute towards reducing DNR resistance in THP-1/A cells.

Co-stimulatory and co-inhibitory pathways in cancer immunotherapy

Cancer remains the leading cause of death worldwide. Traditional treatments such as surgery, radiation, and chemotherapy have had limited efficacy, especially with late stage cancers. Cancer immunotherapy and targeted therapy have revolutionized how cancer is treated, especially in patients with late stage disease. In 2013 cancer immunotherapy was named the breakthrough of the year, partially due to the established efficacy of blockade of CTLA-4 and PD-1, both T cell co-inhibitory molecules involved in tumor-induced immunosuppression. Though early trials promised success, toxicity and tolerance to immunotherapy have hindered long-term successes. Optimizing the use of co-stimulatory and co-inhibitory pathways has the potential to increase the effectiveness of T cell-mediated antitumor immune response, leading to increased efficacy of cancer immunotherapy. This review will address major T cell co-stimulatory and co-inhibitory pathways and the role they play in regulating immune responses during cancer development and treatment.

Transcriptomic but not genomic variability confers phenotype of breast cancer stem cells

Background

Breast cancer stem cells (BCSCs) are considered responsible for cancer relapse and drug resistance. Understanding the identity of BCSCs may open new avenues in breast cancer therapy. Although several discoveries have been made on BCSC characterization, the factors critical to the origination of BCSCs are largely unclear. This study aimed to determine whether genomic mutations contribute to the acquisition of cancer stem-like phenotype and to investigate the genetic and transcriptional features of BCSCs.

Methods

We detected potential BCSC phenotype-associated mutation hotspot regions by using whole-genome sequencing on parental cancer cells and derived serial-generation spheres in increasing order of BCSC frequency, and then performed target deep DNA sequencing at bulk-cell and single-cell levels. To identify the transcriptional program associated with BCSCs, bulk-cell and single-cell RNA sequencing was performed.

Results

By using whole-genome sequencing of bulk cells, potential BCSC phenotype-associated mutation hotspot regions were detected. Validation by target deep DNA sequencing, at both bulk-cell and single-cell levels, revealed no genetic changes specifically associated with BCSC phenotype. Moreover, single-cell RNA sequencing showed profound transcriptomic variability in cancer cells at the single-cell level that predicted BCSC features. Notably, this transcriptomic variability was enriched during the transcription of 74 genes, revealed as BCSC markers. Breast cancer patients with a high risk of relapse exhibited higher expression levels of these BCSC markers than those with a low risk of relapse, thereby highlighting the clinical significance of predicting breast cancer prognosis with these BCSC markers.

Conclusions

Transcriptomic variability, not genetic mutations, distinguishes BCSCs from non-BCSCs. The identified 74 BCSC markers have the potential of becoming novel targets for breast cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s40880-018-0326-8) contains supplementary material, which is available to authorized users.

Tumor cell-associated immune checkpoint molecules - Drivers of malignancy and stemness

Inhibitory or stimulatory immune checkpoint molecules are expressed on a sizeable fraction of tumor cells in different tumor types. It was thought that the main function of tumor cell-associated immune checkpoint molecules would be the modulation (down- or upregulation) of antitumor immune responses. In recent years, however, it has become clear that the expression of immune checkpoint molecules on tumor cells has important consequences on the biology of the tumor cells themselves. In particular, a causal relationship between the expression of these molecules and the acquisition of malignant traits has been demonstrated. Thus, immune checkpoint molecules have been shown to promote the epithelial-mesenchymal transition of tumor cells, the acquisition of tumor-initiating potential and resistance to apoptosis and antitumor drugs, as well as the propensity to disseminate and metastasize. Herein, we review this evidence, with a main focus on PD-L1, the most intensively investigated tumor cell-associated immune checkpoint molecule and for which most information is available. Then, we discuss more concisely other tumor cell-associated immune checkpoint molecules that have also been shown to induce the acquisition of malignant traits, such as PD-1, B7-H3, B7-H4, Tim-3, CD70, CD28, CD137, CD40 and CD47. Open questions in this field as well as some therapeutic approaches that can be derived from this knowledge, are also addressed.

Leukemia Cells and the Cytokine Network: Therapeutic Prospects

The network and balance of cytokines is of major importance in maintaining proper homeostasis of hematopoiesis. Abnormalities in this network may result in a variety of blood disorders; however, the role of this network is not clear in leukemia. The use of antineoplastic agents has improved the survival rate of some types of leukemia, and adjunctive therapy with cytokines may be helpful. Chemotherapeutic approaches are no longer the best choice because cytotoxicity may affect normal and leukemic cells, and leukemic cells may develop resistance to the chemotherapeutic agent. Induction of differentiation to a mature phenotype and the control of apoptotic-gene expression have provided other possible alternative therapies. Combined effects of cytokines and vitamin derivatives such as retinoic acid (RA) and 1, 25 dihydroxyvitamin D3 (VD3) were found more beneficial than any of these agents individually. These agents exhibit cooperative effects, potentiate each other's effects, or both. Therefore, understanding the hematopoietic actions of these agents, their interactions with their receptors, and their differentiation signaling pathways may result In the design of new therapies. However, the role of cytokines in apoptosis is controversial because in some cases they were found to increase tumor cell resistance to apoptosis-inducing agents. Recent studies in the molecular biology of gene regulation, transcription factors, and repressors have led to new possible approaches such as differentiation therapy for the treatment of leukemia. In addition, the development of drugs that act on the molecular level such as imatinib is just the beginning of a new era in molecular targeted therapy in which the drug acts specifically on the leukemic cell. There are many possible combinations of cytokines, retinoids, and VD3, and perhaps the best therapeutic combination is yet to be described. This minireview is an update on the role of cytokines and the therapeutic potential of combinations with agents such as RA, VD3, and other chemotherapeutic agents.

Protein biomarkers of ovarian cancer: the forest and the trees

The goal of effective population-based screening for ovarian cancer remains elusive despite intense efforts aimed at improving upon biomarker and imaging modalities. While dozens of potential serum biomarkers for ovarian cancer have been identified in recent years, none have yet overcome the limitations that have hindered the clinical use of CA-125. Avenues of opportunity in biomarker development are emerging as investigators are beginning to appreciate the significance of remote, as well as local or regional, sources of biomarkers in the construction of diagnostic panels, as well as the importance of evaluating biomarkers in prediagnostic settings. As the list of candidate biomarkers of ovarian cancer continues to grow, refinements in the methods through which specific proteins are selected for further development as components of diagnostic panels are desperately sought. Such refinements must take into account both the bioinformatic and biological significance of each candidate. Approaches incorporating these considerations may potentially overcome the challenges to early detection posed by the histological heterogeneity of ovarian cancer. Here, we review the recent progress achieved in efforts to develop diagnostic biomarker panels for ovarian cancer and discuss the challenges that remain.

Effective and specific inhibition of the CD40-CD154 costimulatory interaction by a naphthalenesulphonic acid derivative

Costimulatory interactions are important regulators of T-cell activation and, hence, promising therapeutic targets in autoimmune diseases as well as in transplant recipients. Following our recent identification of the first small-molecule inhibitors of the CD40-CD154 costimulatory protein-protein interaction (J Mol Med 87, 2009, 1133), we continued our search within the chemical space of organic dyes, and we now report the identification of the naphthalenesulphonic acid derivative mordant brown 1 as a more active, more effective, and more specific inhibitor. Flow cytometry experiments confirmed its ability to concentration-dependently inhibit the CD154(CD40L)-induced cellular responses in human THP-1 cells at concentrations well below cytotoxic levels. Binding experiments showed that it not only inhibits the CD40-CD154 interaction with sub-micromolar activity, but it also has considerably more than 100-fold selectivity toward this interaction even when compared to other members of the tumor necrosis factor superfamily pairs such as TNF-R1-TNF-α, BAFF-R(CD268)-BAFF(CD257/BLys), OX40(CD134)-OX40L(CD252), RANK(CD265)-RANKL(CD254/TRANCE), or 4-1BB(CD137)-4-1BBL. There is now sufficient structure-activity relationship information to serve as the basis of a drug discovery initiative targeting this important costimulatory interaction.

Innate immune signaling in the myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are heterogeneous clonal hematologic malignancies characterized by cytopenias caused by ineffective hematopoiesis and propensity to progress to acute myeloid leukemia. Innate immunity provides immediate protection against pathogens by coordinating activation of signaling pathways in immune cells. Given the prominent role of the innate immune pathway in regulating hematopoiesis, it is not surprising that aberrant signaling of this pathway is associated with hematologic malignancies. Increased activation of the innate immune pathway may contribute to dysregulated hematopoiesis, dysplasia, and clonal expansion in myelodysplastic syndromes.

Molecular mechanism and function of CD40/CD40L engagement in the immune system

SUMMARY

During the generation of a successful adaptive immune response, multiple molecular signals are required. A primary signal is the binding of cognate antigen to an antigen receptor expressed by T and B lymphocytes. Multiple secondary signals involve the engagement of costimulatory molecules expressed by T and B lymphocytes with their respective ligands. Because of its essential role in immunity, one of the best characterized of the costimulatory molecules is the receptor CD40. This receptor, a member of the tumor necrosis factor receptor family, is expressed by B cells, professional antigen-presenting cells, as well as non-immune cells and tumors. CD40 binds its ligand CD40L, which is transiently expressed on T cells and other non-immune cells under inflammatory conditions. A wide spectrum of molecular and cellular processes is regulated by CD40 engagement including the initiation and progression of cellular and humoral adaptive immunity. In this review, we describe the downstream signaling pathways initiated by CD40 and overview how CD40 engagement or antagonism modulates humoral and cellular immunity. Lastly, we discuss the role of CD40 as a target in harnessing anti-tumor immunity. This review underscores the essential role CD40 plays in adaptive immunity.

Co-expression of 9-O-acetylated sialoglycoproteins and their binding proteins on lymphoblasts of childhood acute lymphoblastic leukemia: an anti-apoptotic role

Enhanced levels of 9-O-acetylated sialoglycoproteins (Neu5,9Ac2GPs) as disease-associated molecules was reported to act as signaling molecules for promoting survival of lymphoblasts in childhood acute lymphoblastic leukemia (ALL). Here, we searched for potential physiological ligands for Neu5,9Ac2GPs that could be involved in modulating the survival of lymphoblasts. Accordingly, we examined the presence of binding proteins for Neu5,9Ac2GPs on cell lines and primary cells of patients with B- and T-ALL, at presentation of the disease. Peripheral blood mononuclear cells from normal healthy donors and cells from myeloid leukemia patients were used for comparison. Neu5,9Ac2GPs-binding proteins (BPs) were specifically detected on the surface of both T- and B-ALL-lymphoblasts and ALL-cell lines along with the consistent presence of Neu5,9Ac2GPs. The Neu5,9Ac2GPs and BPs also co-localized on the cell surface and interacted specificallyin vitro. Apoptosis of lymphoblasts, induced by serum starvation, was reversed in the presence of purified Neu5,9Ac2GPs due to possible engagement of BPs, and the anti-apoptotic role of this interaction was established. This is the first report of the presence of potential physiological ligands for disease-associated molecules like Neu5,9Ac2GPs, the interaction of which is able to trigger an anti-apoptotic signal conferring a survival advantage to leukemic cells in childhood ALL.

The platelet as an immune cell-CD40 ligand and transfusion immunomodulation

The discovery that platelets possess cell membrane, cytoplasmic, and secreted forms of the co-stimulatory molecule CD40 ligand (CD40L, also known as CD154) has led to a revolution in the view of this anucleate, differentiated cell fragment, previously thought only to be involved in blood clotting (hemostasis). During the last decade, it has become clear that platelets function in innate and adaptive immunity and possess pro-inflammatory, as well as pro-thrombotic properties. They interact not only with other platelets and endothelial cells, but also with lymphocytes, dendritic cells, and structural cells such as fibroblasts. Soluble forms of CD40L (sCD40L) in the human circulation are almost entirely derived from platelets. Elevated levels of CD40L are associated with clinically important conditions, such as vascular disease, abnormal clotting (thrombosis), lung injury, and autoimmune disease. Each year millions of platelet transfusions are given to patients that contain large amounts of sCD40L. sCD40L in the supernatant of stored platelets can induce cytokines, chemokines, and lipid mediators by activating CD40 bearing cells. Increased levels of sCD40L in transfused blood are associated with transfusion-related acute lung injury, a potentially fatal complication, as well as more common, milder transfusion reactions such as fever and rigors. These effects come under the rubric of transfusion immunomodulation, which postulates that transfusion recipient biology, particularly immune function, is dramatically altered by transfusion of stored allogeneic blood.

The granulocyte macrophage colony stimulating factor (GM-CSF) regulates amyloid beta (Abeta) production

One of the hallmarks of Alzheimer's disease (AD) is the accumulation of amyloid beta (Abeta) plaques in the brain parenchyma. An inflammatory component to AD has been suggested in association with increased cytokine release. We have previously shown that CD40L stimulation of microglia induces increases in pro-inflammatory cytokines such as interleukin-1beta (IL-1beta), IL-6, IL-8 and GM-CSF. We have also shown that CD40L stimulation increases Abeta levels in HEK-293 cells over-expressing both the amyloid precursor protein (APP) and CD40 (HEK/APPsw/CD40). In this study, we show that GM-CSF neutralizing antibodies mitigate the CD40L-induced production of Abeta in HEK/APPsw/CD40 cells. In addition, we demonstrate that treatment of these cells with recombinant GM-CSF significantly increases Abeta levels. Furthermore, we show that shRNA silencing of the GM-CSF receptor gene significantly reduces Abeta levels to below base line in non-stimulated HEK/APPsw/CD40 cells. Analysis of cell surface proteins revealed that silencing of the GM-CSF receptor also decreases APP endocytosis (therefore reducing the availability of APP to be cleaved in the endosomes). Taken together, our results suggest that GM-CSF operates downstream of CD40/CD40L interaction and that GM-CSF modulates Abeta production by influencing APP trafficking. GM-CSF signaling may be a suitable therapeutic target against Abeta production in AD.

Nuclear factor of activated T cells (NFAT) mediates CD154 expression in megakaryocytes

Platelets are an abundant source of CD40 ligand (CD154), an immunomodulatory and proinflammatory molecule implicated in the onset and progression of several inflammatory diseases, including systemic lupus erythematosus (SLE), diabetes, and cardiovascular disease. Heretofore considered largely restricted to activated T cells, we initiated studies to investigate the source and regulation of platelet-associated CD154. We found that CD154 is abundantly expressed in platelet precursor cells, megakaryocytes. We show that CD154 is expressed in primary human CD34+ and murine hematopoietic precursor cells only after cytokine-driven megakaryocyte differentiation. Furthermore, using several established megakaryocyte-like cells lines, we performed promoter analysis of the CD154 gene and found that NFAT, a calcium-dependent transcriptional regulator associated with activated T cells, mediated both differentiation-dependent and inducible megakaryocyte-specific CD154 expression. Overall, these data represent the first investigation of the regulation of a novel source of CD154 and suggests that platelet-associated CD154 can be biochemically modulated.

Antiproliferative and apoptotic effects of two new gold(III) methylsarcosinedithiocarbamate derivatives on human acute myeloid leukemia cells in vitro

[Au(MSDT)Cl2] (dichloro[methyl N-(dithiocarboxy-kS,kS')-N-methylglicinato]gold(III)) and [Au(MSDT)Br2] (dibromo[methyl N-(dithiocarboxy-kS,kS')-N-methylglicinato]gold(III)) gold(III) dithiocarbamate derivatives are two newly synthesized gold(III) derivatives of methylsarcosinedithiocarbamate, containing a sulfur chelating ligand that is able to bind the metal center strongly, so preventing interactions with sulfur-containing enzymes; in fact these reactions are believed to be responsible for the nephrotoxicity induced by the platinum(II)-based drugs. Their activity has been compared with the well-known platinum-based anticancer agent cisplatin on a panel of acute myelogenous leukemia cell lines representing different French-American-British subtypes and in the Philadelphia-positive cell line K562. Both compounds suppressed, in a dose-dependent manner, colony formation in methylcellulose with ID50 values of about 10-fold lower than that of the reference drug. After a short exposure (18 h), our compounds, but not cisplatin, were able to: downregulate the antiapoptotic molecule Bcl-2, upregulate the proapoptotic molecule Bax and induce apoptosis, as determined by a strong induction of APO2.7 and phosphatidylserine exposure. Finally, after a 72-h exposure, both gold(III) dithiocarbamate derivatives determined modest cell cycle modifications, but induced DNA fragmentation in all myeloid cell lines tested. Altogether, our results indicate that these new gold(III) dithiocarbamate derivatives might represent novel potentially active drugs for the management of myeloid leukemia, able to combine cytostatic and apoptotic activity with reduced nephrotoxicity.

Microarray analysis of the differential transformation mediated by Kirsten and Harvey Ras oncogenes in a human colorectal adenocarcinoma cell line

Colorectal cancer arises after a series of mutational events in the colon epithelia and is often used as a model of the multistep progression of tumorigenesis. Mutations in Ki-Ras have been detected in some 50% of cases and are thought to occur at an early stage. Almost never do mutations arise in the loci of other Ras isoforms (Ha- and N-), leading to the assumption that Ki-Ras plays a unique role in tumorigenesis. In order to examine the distinctive function that Ki-Ras plays in cancer development in the colon, we introduced constitutively active mutant Ki- and Ha-Ras genes into an intermediate-stage colon adenoma cell line (Caco-2). We found that mutant active Ha-RasV12 was more efficient at transforming these colon epithelial cells as assessed by anchorage-independent growth, tumor formation in SCID mice and the development of mesenchymal morphology compared to transformation by Ki-RasV12. We conducted microarray analysis in an attempt to reveal the genes whose aberrant expression is a direct result of overexpression of either Ki-RasV12 or Ha-RasV12. We used Clontech's Atlas cancer cDNA (588 genes) and RZPD's Onco Set 1 (1,544 genes) arrays. We identified fewer genes that were commonly regulated than were differentially expressed between Ki- and Ha-RasV12 isoforms. Specifically, we found that Ki-RasV12 regulated genes involved in cytokine signaling, cell adhesion and colon development, whereas Ha-RasV12 mainly regulated genes involved in controlling cell morphology, correlating to an epithelial-mesenchymal transition only observed in these cells. Our results demonstrate how 2 Ras isoforms regulate disparate biologic processes, revealing a number of genes whose deregulated expression may influence colon carcinogenesis (supplementary material for this article can be found on the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html).

Localization of candidate stem and progenitor cell markers within the human cornea, limbus, and bulbar conjunctiva in vivo and in cell culture

Corneal diseases are some of the most prevalent causes of blindness worldwide. While the most common treatment for corneal blindness is the transplantation of cadaver corneas, expanded limbal stem cells are finding recent application. Unknown, however, is the identity of the actual repopulating stem cell fraction utilized in both treatments and the critical factors governing successful engraftment and repopulation. In order to localize potential stem cell populations in vivo, we have immunohistochemically mapped a battery of candidate stem and progenitor cell markers including c-Kit and other growth factor receptors, nuclear markers including DeltaNp63, as well as adhesion factors across the cornea and distal sclera. Cell populations that differentially and specifically stained for some of these markers include the basal and superficial limbal/conjunctival epithelium and scattered cells within the substantia propria of the bulbar conjunctiva. We have also determined that the culture of differentiated cornea epithelial cells as dissociated and explant cultures induces the expression of several markers previously characterized as candidate limbal stem cell markers. This study provides a foundation to explore candidate corneal stem cell populations. As well, we show that expression of traditional stem cell markers may not be reliable indicator of stem cell content during limbal stem cell expansion in vitro and could contribute to the variable success rates of corneal stem cell transplantation.

A randomized trial of washed red blood cell and platelet transfusions in adult acute leukemia [ISRCTN76536440]

BACKGROUND: Platelet transfusion is universally employed in acute leukemia. Platelet concentrate supernatants contain high concentrations of biologic mediators that might impair immunity. We investigated whether washed platelet and red cell transfusions could improve clinical outcomes in adult patients with acute leukemia. METHODS: A pilot randomized trial of washed, leukoreduced ABO identical transfusions versus leukoreduced ABO identical transfusions was conducted in 43 adult patients with acute myeloid or lymphoid leukemia during 1991-94. Primary endpoints to be evaluated were platelet transfusion refractoriness, infectious and bleeding complications and overall survival. RESULTS: There were no significant differences in infectious or major bleeding complications and only one patient required HLA matched platelet transfusions. Minor bleeding was more frequent in the washed, leukoreduced arm of the study. Confirmed transfusion reactions were more frequent in the leukoreduced arm of the study. Overall survival was superior in the washed arm of the study (40% versus 22% at 5 years), but this difference was not statistically significant (p = 0.36). A planned subset analysis of those Collapse

Key Words Collapse

MESH Headings Collapse

Grants Collapse

Affiliation(s)

Neil Blumberg Department of Pathology & Laboratory Medicine (Transfusion Medicine Unit), University of Rochester Medical Center, Box 608, Rochester, NY 14642 USA
Joanna M Heal Department of Medicine (Hematology-Oncology Division), University of Rochester Medical Center, Box 608, Rochester, NY 14642 USA
Jacob M Rowe Department of Medicine (Hematology-Oncology Division), University of Rochester Medical Center, Box 608, Rochester, NY 14642 USA Dept. of Hematology and BMT, Rambam Medical Center, Haifa 31096 Israel

Collapse

CD90/Thy-1 is preferentially expressed on blast cells of high risk acute myeloid leukaemias

Different transformation mechanisms have been proposed for elderly acute myeloid leukaemia (AML) and secondary AML (sAML) when compared with de novo AML or AML of younger patients. However, little is known regarding differences in the immunophenotypic profile of blast cells in these diseases. We systematically analysed, by flow cytometry, 148 patients affected by de novo (100 cases) or sAML (48 cases). By defining a cut-off level of 20% of CD34+ cells co-expressing CD90, the frequency of CD90+ cases was higher in sAML (40%) versus de novo AML (6%, P < 0.001), elderly AML (>60 years) (24%) versus AML of younger patients (10%, P = 0.010) and poor- versus good-risk karyotypes (according to the Medical Research Council classification, P < 0.001). The correlation between CD90 expression, sAML and unfavourable karyotypes was confirmed by analysing the subset of CD34+ AML cases alone (91/148). Consistently, univariate analysis showed that expression of CD90 was statistically relevant in predicting a shorter survival in CD90+ AML patients (P = 0.042). Our results, demonstrating CD90 expression in AML with unfavourable clinical and biological features, suggest an origin of these diseases from a CD90-expressing haemopoietic progenitor and indicate the use of CD90 as an additional marker of prognostic value in AML.

Mycosis fungoides shows concurrent deregulation of multiple genes involved in the TNF signaling pathway: an expression profile study

Mycosis fungoides (MF) is the most frequent type of cutaneous T-cell lymphoma, whose diagnosis and study is hampered by its morphologic similarity to inflammatory dermatoses (ID) and the low proportion of tumoral cells, which often account for only 5% to 10% of the total tissue cells. cDNA microarray studies using the CNIO OncoChip of 29 MF and 11 ID cases revealed a signature of 27 genes implicated in the tumorigenesis of MF, including tumor necrosis factor receptor (TNFR)-dependent apoptosis regulators, STAT4, CD40L, and other oncogenes and apoptosis inhibitors. Subsequently a 6-gene prediction model was constructed that is capable of distinguishing MF and ID cases with unprecedented accuracy. This model correctly predicted the class of 97% of cases in a blind test validation using 24 MF patients with low clinical stages. Unsupervised hierarchic clustering has revealed 2 major subclasses of MF, one of which tends to include more aggressive-type MF cases including tumoral MF forms. Furthermore, signatures associated with abnormal immunophenotype (11 genes) and tumor stage disease (5 genes) were identified.