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The treatment of chronic myeloid leukemia (CML), a clonal myeloproliferative disorder has improved recently, but most patients have not yet been cured. Some patients develop resistance to the available tyrosine kinase treatments. Persistence of residual quiescent CML stem cells (LSCs) that later resume proliferation is another common cause of recurrence or relapse of CML. Eradication of quiescent LSCs is a promising approach to prevent recurrence of CML. Here we report on new biophysical differences between quiescent and proliferating CD34+ LSCs, and speculate how this information could be of use to eradicate quiescent LSCs. Using AFM measurements on cells collected from four untreated CML patients, substantial differences are observed between quiescent and proliferating cells in the elastic modulus, pericellular brush length and its grafting density at the single cell level. The higher pericellular brush densities of quiescent LSCs are common for all samples. The significance of these observations is discussed.

Biomechanical properties of single cells in vitro or ex vivo and their pericellular interfaces have recently attracted a lot of attention as a potential biophysical (and possibly prognostic) marker of various diseases and cell abnormalities. At the same time, the influence of the cell environment on the biomechanical properties of cells is not well studied. Here we use atomic force microscopy to demonstrate that cell-cell communication can have a profound effect on both cell elasticity and its pericellular coat. A human pre-B p190BCR/ABL acute lymphoblastic leukemia cell line (ALL3) was used in this study. Assuming that cell-cell communication is inversely proportional to the distance between cells, we study ALL3 cells in vitro growing at different cell densities. ALL3 cells demonstrate a clear density dependent behavior. These cells grow very well if started at a relatively high cell density (HD, >2 × 105 cells ml-1) and are poised to grow at low cell density (LD

Tumors contain heterogeneous cell populations and achieve dominance by functioning as collective systems. The mechanisms underlying the aberrant growth and interactions between cells are not very well understood. The pre-B acute lymphoblastic leukemia cells we studied were obtained directly from a patient with Ph+ ALL. A new Ph+ ALL cell line (ALL3) was established from the leukemic cells growing as ascitic cells in his pleural fluid. The patient died of his disease shortly after the cells were obtained. ALL3 cells grow well at high cell densities (HD), but not at low cell densities. ALL3 cells are very sensitive to potent tyrosine kinase inhibitors (TKIs) such as Dasatinib and PD166325, but less sensitive to AMN 107, Imatinib, and BMS 214662 (a farnesyl transferase inhibitor). Here, we show that the growth of the LD ALL3 cells can be stimulated to grow in the presence of diffusible, soluble factors secreted by ALL3 cells themselves growing at high density. We also show that exosomes, part of the secretome components, are also able to stimulate the growth of the non-growing LD ALL3 cells and modulate their proliferative behavior. Characterization of the exosome particles also showed that the HD ALL3 cells are able to secret them in large quantities and that they are capable of inducing the growth of the LD ALL3 cells without which they will not survive. Direct stimulation of non-growing LD ALL3 cells using purified exosomes shows that the ALL3 cells can also communicate with each other by means of exchange of exosomes independently of direct cell-cell contacts or diffusible soluble stimulatory factors secreted by HD ALL3 cells.

Quorum sensing (QS) is a generic term used to describe cell-cell communication and collective decision making by bacterial and social insects to regulate the expression of specific genes in controlling cell density and other properties of the populations in response to nutrient supply or changes in the environment. QS mechanisms also have a role in higher organisms in maintaining homeostasis, regulation of the immune system and collective behavior of cancer cell populations. In the present study, we used a p190(BCR-ABL) driven pre-B acute lymphoblastic leukemia (ALL3) cell line derived from the pleural fluid of a terminally ill patient with ALL to test the QS hypothesis in leukemia. ALL3 cells don't grow at low density (LD) in liquid media but grow progressively faster at increasingly high cell densities (HD) in contrast to other established leukemic cell lines that grow well at very low starting cell densities. The ALL3 cells at LD are poised to grow but shortly die without additional stimulation. Supernates of ALL3 cells (HDSN) and some other primary cells grown at HD stimulate the growth of the LD ALL3 cells without which they won't survive. To get further insight into the activation processes we performed microarray analysis of the LD ALL3 cells after stimulation with ALL3 HDSN at days 1, 3, and 6. This screen identified several candidate genes, and we linked them to signaling networks and their functions. We observed that genes involved in lipid, cholesterol, fatty acid metabolism, and B cell activation are most up- or down-regulated upon stimulation of the LD ALL3 cells using HDSN. We also discuss other pathways that are differentially expressed upon stimulation of the LD ALL3 cells. Our findings suggest that the Ph+ ALL population achieves dominance by functioning as a collective aberrant ecosystem subject to defective quorum-sensing regulatory mechanisms.

B‐cell novel protein‐1 (BCNP1) or Family member of 129C (FAM129C) was identified as a B‐cell‐specific plasma‐membrane protein. Bioinformatics analysis predicted that BCNP1 might be heavily phosphorylated. The BCNP1 protein contains a pleckstrin homology (PH) domain, two proline‐rich (PR) regions and a Leucine Zipper (LZ) domain suggesting that it may be involved in protein‐protein interactions. Using The Cancer Genome Atlas (TCGA) data sets, we investigated the correlation of alteration of the BCNP1 copy‐number changes and mutations in several cancer types. We also investigated the function of BCNP1 in cellular signalling pathways. We found that BCNP1 is highly altered in some types of cancers and that BCNP1 copy‐number changes and mutations co‐occur with other molecular alteration events for TP53 (tumour protein P53), PIK3CA (Phosphatidylinositol‐4,5‐Bisphosphate 3‐Kinase, Catalytic Subunit Alpha), MAPK1 (mitogen‐activated protein kinase‐1; ERK: extracellular signal regulated kinase), KRAS (Kirsten rat sarcoma viral oncogene homolog) and AKT2 (V‐Akt Murine Thymoma Viral Oncogene Homolog 2). We also found that PI3K (Phoshoinositide 3‐kinase) inhibition and p38 MAPK (p38 mitogen‐activated protein kinase) activation leads to reduction in phosphorylation of BCNP1 at serine residues, suggesting that BCNP1 phosphorylation is PI3K and p38MAPK dependent and that it might be involved in cancer. Its degradation depends on a proteasome‐mediated pathway.

See related article by Sandberg et al., [Cancer Res 1961;21:678–89][1] . Visit the Cancer Research 75th Anniversary [timeline][2]. German pathologists in the late nineteenth century appear to have been the first to publish observations of mitotic abnormalities in many types of human cancers and

Purpose: Although tyrosine kinase inhibitors have improved survival in advanced gastrointestinal stromal tumor (GIST), complete response is rare and most patients eventually fail the first-line treatment with imatinib. Sunitinib malate is the only approved second-line therapy for patients with imatinib-resistant or imatinib-intolerant GIST. The clinical benefit of sunitinib is genotype-dependent in regards to both primary and secondary mutations, with GIST patients harboring the KITAY502-3ins exon 9 mutation being the most sensitive. Experimental Design: As sunitinib resistance is now emerging, our goal was to investigate mechanisms of progression and to test the efficacy of novel tyrosine kinase inhibitor on these resistant mutants in vitro. N-ethyl-N-nitrosourea mutagenesis of Ba/F3 cells expressing the KITAY502-3ins mutant was used to investigate novel patterns of resistant mutations evolving in the presence of sunitinib. Results: Tumors from patients who developed sunitinib resistance after at least 1 year of radiographic response were analyzed, showing similar findings of a primary KITAY502-3ins mutation and a secondary mutation in the KIT activation loop. Ba/F3 cells expressing these sunitinib-resistant double mutants showed sensitivity to both dasatinib and nilotinib. Conclusions: Sunitinib resistance in GIST shares similar pathogenetic mechanisms identified in imatinib failure, with acquisition of secondary mutations in the activation domain after an extended initial response to the drug. Moreover, in vitro mutagenesis with or without N-ethyl-N-nitrosourea of Ba/F3 cells expressing KITAY502-3ins showed acquisition of secondary mutations restricted to the second kinase domain of KIT. In contrast, in vitro resistance to imatinib produces a broader spectrum of secondary mutations including mutations in both KIT kinase domains. (Clin Cancer Res 2009;15(22):686270)

To assess the usefulness of 4-hydroperoxycyclophosphamide (4-HC) and Etoposide (VP-16) as a purging agent for myeloma cells in bone marrow ex-vivo, myeloma cell lines (SK-RCS-1, RPMI-8226), lymphoma cell line (SK-DHL-2) and normal bone marrow (BM) cells were treated at different concentrations of 4-HC, VP-16. In separate experiments, LAK cells or antibodies were also used to treat the above cell lines. Clonogenic tumor cells from all three cell lines could be reduced by more than 4 logs, when treated alone or as a mixture with irradiated normal bone marrow cells at a 4-HC concentration of 60 mumol/l. Under similar conditions, approximately 1% of normal BM myeloid progenitor granulocyte-macrophage colony forming cells (CFU-GM) survived. The results with LAK cells and antibodies were also encouraging. These observations support the use of various purging methods for myeloma cells for autologous bone marrow transplantation.

Persistently activated or tyrosine-phosphorylated STAT3 (pSTAT3) is found in 50% of lung adenocarcinomas. pSTAT3 is found in primary adenocarcinomas and cell lines harboring somatic-activating mutations in the tyrosine kinase domain of EGFR. Treatment of cell lines with either an EGFR inhibitor or an src kinase inhibitor had no effect on pSTAT3 levels, whereas a pan-JAK inhibitor (P6) blocked activation of STAT3 and inhibited tumorigenesis. Cell lines expressing these persistently activated mutant EGFRs also produced high IL-6 levels, and blockade of the IL-6/gp130/JAK pathway led to a decrease in pSTAT3 levels. In addition, reduction of IL-6 levels by RNA interference led to a decrease in tumorigenesis. Introduction of persistently activated EGFR into immortalized breast epithelial cells led to tumorigenesis, IL-6 expression, and STAT3 activation, all of which could be inhibited with P6 or gp130 blockade. Furthermore, inhibition of EGFR activity in multiple cell lines partially blocked transcription of IL-6 and concurrently decreased production and release of IL-6. Finally, immunohistochemical analysis revealed a positive correlation between pSTAT3 and IL-6 positivity in primary lung adenocarcinomas. Therefore, mutant EGFR could activate the gp130/JAK/STAT3 pathway by means of IL-6 upregulation in primary human lung adenocarcinomas, making this pathway a potential target for cancer treatment.

Author(s): Tefferi, Ayalew; Kantarjian, Hagop; Rajkumar, S Vincent; Baker, Lawrence H; Abkowitz, Jan L; Adamson, John W; Advani, Ranjana Hira; Allison, James; Antman, Karen H; Bast, Robert C; Bennett, John M; Benz, Edward J; Berliner, Nancy; Bertino, Joseph; Bhatia, Ravi; Bhatia, Smita; Bhojwani, Deepa; Blanke, Charles D; Bloomfield, Clara D; Bosserman, Linda; Broxmeyer, Hal E; Byrd, John C; Cabanillas, Fernando; Canellos, George Peter; Chabner, Bruce A; Chanan-Khan, Asher; Cheson, Bruce; Clarkson, Bayard; Cohn, Susan L; Colon-Otero, Gerardo; Cortes, Jorge; Coutre, Steven; Cristofanilli, Massimo; Curran, Walter J; Daley, George Q; DeAngelo, Daniel J; Deeg, H Joachim; Einhorn, Lawrence H; Erba, Harry P; Esteva, Francisco J; Estey, Elihu; Fidler, Isaiah J; Foran, James; Forman, Stephen; Freireich, Emil; Fuchs, Charles; George, James N; Gertz, Morie A; Giralt, Sergio; Golomb, Harvey; Greenberg, Peter; Gutterman, Jordan; Handin, Robert I; Hellman, Samuel; Hoff, Paulo Marcelo; Hoffman, Ronald; Hong, Waun Ki; Horowitz, Mary; Hortobagyi, Gabriel N; Hudis, Clifford; Issa, Jean Pierre; Johnson, Bruce Evan; Kantoff, Philip W; Kaushansky, Kenneth; Khayat, David; Khuri, Fadlo R; Kipps, Thomas J; Kripke, Margaret; Kyle, Robert A; Larson, Richard A; Lawrence, Theodore S; Levine, Ross; Link, Michael P; Lippman, Scott M; Lonial, Sagar; Lyman, Gary H; Markman, Maurie; Mendelsohn, John; Meropol, Neal J; Messinger, Yoav; Mulvey, Therese M; O'Brien, Susan; Perez-Soler, Roman; Pollock, Raphael; Prchal, Josef

Mutation in the ABL kinase domain is the principal mechanism of imatinib resistance in patients with chronic myelogenous leukemia. Many mutations favor active kinase conformations that preclude imatinib binding. Because the active forms of ABL and SRC resemble one another, we tested two dual SRC-ABL kinase inhibitors, AP23464 and PD166326, against 58 imatinib-resistant (IM R ) BCR/ABL kinase variants. Both compounds potently inhibit most IM R variants, and in vitro drug selection demonstrates that active (AP23464) and open (PD166326) conformation-specific compounds are less susceptible to resistance than imatinib. Combinations of inhibitors suppressed essentially all resistance mutations, with the notable exception of T315I. Guided by mutagenesis studies and molecular modeling, we designed a series of AP23464 analogues to target T315I. The analogue AP23846 inhibited both native and T315I variants of BCR/ABL with submicromolar potency but showed nonspecific cellular toxicity. Our data illustrate how conformational dynamics of the ABL kinase accounts for the activity of dual SRC-ABL inhibitors against IM R -mutants and provides a rationale for combining conformation specific inhibitors to suppress resistance.

Imatinib mesylate is highly effective in newly diagnosed chronic myeloid leukemia (CML), but BCR/ABL (breakpoint cluster region/abelson murine leukemia)–positive progenitors persist in most patients with CML treated with imatinib mesylate, indicating the need for novel therapeutic approaches. In this study, we have used the murine CML-like myeloproliferative disorder as a platform to characterize the pharmacokinetic, signal transduction, and antileukemic properties of PD166326, one of the most potent members of the pyridopyrimidine class of protein tyrosine kinase inhibitors. In mice with the CML-like disease, PD166326 rapidly inhibited Bcr/Abl kinase activity after a single oral dose and demonstrated marked antileukemic activity in vivo. Seventy percent of PD166326-treated mice achieved a white blood cell (WBC) count less than 20.0 × 109/L (20 000/μL) at necropsy, compared with only 8% of imatinib mesylate–treated animals. Further, two thirds of PD166326-treated animals had complete resolution of splenomegaly, compared with none of the imatinib mesylate–treated animals. Consistent with its more potent antileukemic effect in vivo, PD166326 was also superior to imatinib mesylate in inhibiting the constitutive tyrosine phosphorylation of numerous leukemia-cell proteins, including the src family member Lyn. PD166326 also prolonged the survival of mice with imatinib mesylate–resistant CML induced by the Bcr/Abl mutants P210/H396P and P210/M351T. Altogether, these findings demonstrate the potential of more potent Bcr/Abl inhibitors to provide more effective antileukemic activity. Clinical development of PD166326 or a related analog may lead to more effective drugs for the treatment of de novo and imatinib mesylate–resistant CML.

In Philadelphia-positive (Ph(+)) leukemia, point mutations within the Bcr-Abl kinase domain emerged as a major mechanism of resistance to imatinib mesylate. We established a cell-based screening strategy for detection of clinically relevant point mutations using Bcr-Abl-transformed Ba/F3 cells. We identified 32 different single-point mutations within the kinase domain of Bcr-Abl. The pattern and frequency of mutations in this cell culture-based screen resembled the pattern and frequency observed in resistant patients. We then applied this screen to an alternative Abl kinase inhibitor. Using PD166326, the frequency of resistant colonies emerging at 5 to 10 times the median growth inhibition (IC50) of PD166326 was significantly lower than with imatinib. In addition, PD166326 produced a distinct pattern of Bcr-Abl mutations. The majority of mutations that came up with both imatinib and PD166326 could effectively be suppressed by increasing the dose of PD166326 to 50 to 500 nM. In contrast, only a few mutations could be suppressed by increasing the imatinib dose to 5 to 10 microM. However, 3 mutations affecting F317 displayed complete resistance to PD166326, but could be effectively inhibited by standard concentrations of imatinib. Thus, this robust and simple screening system provides a rational basis for combinatorial and sequential treatment strategies in targeted cancer therapy.

c-Abl, a conserved nonreceptor tyrosine kinase, integrates genotoxic stress responses, acting as a transducer of both pro- and antiapoptotic effector pathways. Nuclear c-Abl seems to interact with the p53 homolog p73 to elicit apoptosis. Although several observations suggest that cytoplasmic localization of c-Abl is required for antiapoptotic function, the signals that mediate its antiapoptotic effect are largely unknown. Here we show that worms carrying an abl-1 deletion allele, abl-1(ok171), are specifically hypersensitive to radiation-induced apoptosis in the Caenorhabditis elegans germ line. Our findings delineate an apoptotic pathway antagonized by ABL-1, which requires sequentially the cell cycle checkpoint genes clk-2, hus-1 and mrt-2; the C. elegans p53 homolog, cep-1; and the genes encoding the components of the conserved apoptotic machinery, ced-3, ced-9 and egl-1. ABL-1 does not antagonize germline apoptosis induced by the DNA-alkylating agent ethylnitrosourea. Furthermore, worms treated with the c-Abl inhibitor STI-571 (Gleevec; used in human cancer therapy), two newly synthesized STI-571 variants or PD166326 had a phenotype similar to that generated by abl-1(ok171). These studies indicate that ABL-1 distinguishes proapoptotic signals triggered by two different DNA-damaging agents and suggest that C. elegans might provide tissue models for development of anticancer drugs.

Amyloid-β (Aβ) peptides, consisting mainly of 40 and 42 aa (Aβ40 and Aβ42, respectively), are metabolites of the amyloid precursor protein and are believed to be major pathological determinants of Alzheimer's disease. The proteolytic cleavages that form the Aβ N and C termini are catalyzed by β-secretase and γ-secretase, respectively. Here we demonstrate that γ-secretase generation of Aβ in an N2a cell-free system is ATP dependent. In addition, the Abl kinase inhibitor imatinib mesylate (Gleevec, or STI571), which targets the ATP-binding site of Abl and several other tyrosine kinases, potently reduces Aβ production in the N2a cell-free system and in intact N2a cells. Both STI571 and a related compound, inhibitor 2, also reduce Aβ production in rat primary neuronal cultures and in vivo in guinea pig brain. STI571 does not inhibit the γ-secretase-catalyzed S3 cleavage of Notch-1. Furthermore, production of Aβ and its inhibition by STI571 were demonstrated to occur to similar extents in both Abl -/- and WT mouse fibroblasts, indicating that the effect of STI571 on Aβ production does not involve Abl kinase. The efficacy of STI571 in reducing Aβ without affecting Notch-1 cleavage may prove useful as a basis for developing novel therapies for Alzheimer's disease.

Dok-1 is an adaptor protein that is a substrate for Bcr-Abl and other tyrosine protein kinases. The presence of pleckstrin homology and phosphotyrosine binding domains as well as multiple tyrosine phosphorylation sites suggests that Dok-1 is involved in protein-protein and/or protein-lipid interactions. Here we show that stimulation of Mo7 hematopoietic cells with c-Kit ligand (KL) induces phosphatidylinositol (PI) 3-kinase-dependent tyrosine phosphorylation and membrane recruitment of Dok-1. Addition of the K-Ras membrane-targeting motif to Dok-1 generated a constitutively membrane-bound Dok-1 protein whose tyrosine phosphorylation was independent of PI 3-kinase. Membrane localization of Dok-1 was required for its ability to function as a negative regulator of cell proliferation. Additional experiments revealed that Dok-1 associated with the juxtamembrane region and C-terminal tail of c-Kit. Lyn promoted phosphorylation of c-Kit and association of c-Kit and Dok-1. Both Lyn and Tec were capable of phosphorylating Dok-1. However, the use of primary bone marrow mast cells from normal and Lyn-deficient mice demonstrated that Lyn is required for KL-dependent Dok-1 tyrosine phosphorylation. Taken together, these data indicate that activation of PI 3-kinase by KL promotes binding of the Dok pleckstrin homology domain and Dok-1 recruitment to the plasma membrane where Dok-1 is phosphorylated by Src and/or Tec family kinases.

The secretome includes all macromolecules secreted by cells, in particular conditions at defined times, allowing cell-cell communication. Cancer cell secretomes that are altered compared to normal cells have shown significant potential for elucidating cancer biology. Proteins of secretomes are secreted by various secretory pathways and can be studied using different methods. Cancer secretomes seem to play an important role in known hallmarks of cancers such as excessive proliferation, reduced apoptosis, immune invasion, angioneogenesis, alteration in energy metabolism, and development of resistance against anti-cancer therapy [1, 2]. If a significant role of an altered secretome can be identified in cancer cells, using advanced mass spectrometry-based techniques, this may allow researchers to screen and characterize the secretome proteins involved in cancer progression and open up new opportunities to develop new therapies. We aim to elaborate upon recent advances in cancer cell secretome analysis using different proteomics techniques. In this review, we highlight the role of the altered secretome in contributing to already recognized and emerging hallmarks of cancer and we discuss new challenges in the field of secretome analysis.

The secretome includes all macromolecules secreted by cells, in particular conditions at defined times, allowing cell–cell communication. Cancer cell secretomes that are altered compared to normal cells have shown significant potential for elucidating cancer biology. Proteins of secretomes are secreted by various secretory pathways and can be studied using different methods. Cancer secretomes seem to play an important role in known hallmarks of cancers such as excessive proliferation, reduced apoptosis, immune invasion, angioneogenesis, alteration in energy metabolism, and development of resistance against anti-cancer therapy [1, 2]. If a significant role of an altered secretome can be identified in cancer cells, using advanced mass spectrometry-based techniques, this may allow researchers to screen and characterize the secretome proteins involved in cancer progression and open up new opportunities to develop new therapies. We aim to elaborate upon recent advances in cancer cell secretome analysis using different proteomics techniques. In this review, we highlight the role of the altered secretome in contributing to already recognized and emerging hallmarks of cancer and we discuss new challenges in the field of secretome analysis.

p62(dok) has been identified as a substrate of many oncogenic tyrosine kinases such as the chronic myelogenous leukemia (CML) chimeric p210(bcr-abl) oncoprotein. It is also phosphorylated upon activation of many receptors and cytoplamic tyrosine kinases. However, the biological functions of p62(dok) in normal cell signaling as well as in p210(bcr-abl) leukemogenesis are as yet not fully understood. Here we show, in hemopoietic and nonhemopoietic cells derived from p62(dok)-(/)- mice, that the loss of p62(dok) results in increased cell proliferation upon growth factor treatment. Moreover, Ras and mitogen-activated protein kinase (MAPK) activation is markedly sustained in p62(dok)-(/)- cells after the removal of growth factor. However, p62(dok) inactivation does not affect DNA damage and growth factor deprivation-induced apoptosis. Furthermore, p62(dok) inactivation causes a significant shortening in the latency of the fatal myeloproliferative disease induced by retroviral-mediated transduction of p210(bcr-abl) in bone marrow cells. These data indicate that p62(dok) acts as a negative regulator of growth factor-induced cell proliferation, at least in part through downregulating Ras/MAPK signaling pathway, and that p62(dok) can oppose leukemogenesis by p210(bcr-abl).

The initial phase of chronic myelogenous leukemia (CML) is triggered by constitutive protein tyrosine kinase activity of the chimeric kinase p210(bcr-abl) (Bcr-Abl). A major substrate of Bcr-Abl was recently identified as the RasGAP-associated 62 kDa docking protein Dok1. Here, we report complex formation between endogenous Dok1 and the SH2 domain-containing phosphatidylinositol polyphosphate 5-phosphatase SHIP1 in hematopoietic cells expressing Bcr-Abl. Expression of Bcr-Abl induced tyrosine phosphorylation of both Dok1 and SHIP1 and the formation of a Dok1/SHIP1 complex. Tyr(P) SHIP1 was also bound to Shc in Bcr-Abl expressing cells. A small amount of Shc/SHIP1/Dok1 trimolecular complex was detected and this was due to binding of Dok1 to SHIP1 that was bound to Shc. In contrast, association of Dok1 with SHIP1 or RasGAP was mutually exclusive. Both the SH2 domain of SHIP1 and the PTB domain of Dok1 were required for complex formation between the two proteins. Neither the specific activity of SHIP1 as an inositol phosphate 5-phosphatase nor the subcellular localization of SHIP1 appeared to be altered by tyrosine phosphorylation. However, the Dok1/SHIP1 complex was only detected in the cytosolic fraction of Bcr-Abl transformed hematopoietic cells. We propose that interaction between Dok1 and SHIP1 modulates the ability of these two proteins to interact with other cytosolic binding partners.

Because of the probable causal relationship between constitutive p210bcr/abl protein tyrosine kinase activity and manifestations of chronic-phase chronic myelogenous leukemia (CML; myeloid expansion), a key goal is to identify relevant p210 substrates in primary chronic-phase CML hematopoietic progenitor cells. We describe here the purification and mass spectrometric identification of a 155-kD tyrosine phosphorylated protein associated with src homologous and collagen gene (SHC) from p210bcr/abl-expressing hematopoietic cells as SHIP2, a recently reported, unique SH2-domain–containing protein closely related to phosphatidylinositol polyphosphate 5-phosphatase SHIP. In addition to an N-terminal SH2 domain and a central catalytic region, SHIP2 (like SHIP1) possesses both potential PTB(NPXY) and SH3 domain (PXXP) binding motifs. Thus, two unique 5-ptases with striking structural homology are coexpressed in hematopoietic progenitor cells. Stimulation of human hematopoietic growth factor responsive cell lines with stem cell factor (SCF), interleukin-3 (IL-3), and granulocyte-macrophage colony-stimulating factor (GM-CSF) demonstrate the rapid tyrosine phosphorylation of SHIP2 and its resulting association with SHC. This finding suggests that SHIP2, like that reported for SHIP1 previously, is linked to downstream signaling events after activation of hematopoietic growth factor receptors. However, using antibodies specific to these two proteins, we demonstrate that, whereas SHIP1 and SHIP2 selectively hydrolyze PtdIns(3,4,5)P3 in vitro, only SHIP1 hydrolyzes soluble Ins(1,3,4,5)P4. Such an enzymatic difference raises the possibility that SHIP1 and SHIP2 may serve different functions. Preliminary binding studies using lysates from p210bcr/abl-expressing cells indicate that both Ptyr SHIP2 and Ptyr SHIP1 bind to the PTB domain of SHC but not to its SH2 domain. Interestingly, SHIP2 was found to selectively bind to the SH3 domain of ABL, whereas SHIP1 selectively binds to the SH3 domain of Src. Furthermore, in contrast to SHIP1, SHIP2 did not bind to either the N-terminal or C-terminal SH3 domains of GRB2. These observations suggest (1) that SHIP1 and SHIP2 may have a different hierarchy of binding SH3 containing proteins and therefore may modulate different signaling pathways and/or localize to different cellular compartments and (2) that they may be substrates for tyrosine phosphorylation by different tyrosine kinases. Because recent evidence has clearly implicated both PI(3,4,5)P3 and PI(3,4)P2 in growth factor-mediated signaling, our finding that both SHIP1 and SHIP2 are constitutively tyrosine phosphorylated in CML primary hematopoietic progenitor cells may thus have important implications in p210bcr/abl-mediated myeloid expansion.

Chronic myelogenous leukemia (CML) is a disease characterized by the presence of p210bcr-abl, a chimeric protein with tyrosine kinase activity. Substrates for p210bcr-abl are likely to be involved in the pathogenesis of CML. Here we describe the purification, cDNA cloning, and characterization of a 56-kDa tyrosine phosphorylated protein, p56dok-2 (Dok-2), from p210bcr-abl expressing cells. The human dok-2 cDNA encodes a 412-amino acid protein with a predicted N-terminal pleckstrin homology domain as well as several other features of a signaling molecule, including 13 potential tyrosine phosphorylation sites, six PXXP motifs, and the ability to bind to p120RasGAP. Dok-2 was shown to be 35% identical to p62dok-1, a recently identified RasGAP binding protein from CML cells, and analysis of the expressed sequence tag data base revealed the presence of at least four additional proteins containing a Dok homology sequence motif. Dok mRNAs were primarily expressed in tissues of hematopoietic origin. These findings strongly suggest that a family of Dok-related proteins exists that bind to RasGAP and may mediate the effects of p210bcr-abl in CML.

Characteristic of chronic myelogenous leukemia (CML) is the presence of the chimeric p210(bcr-abl) protein possessing elevated protein tyrosine kinase activity relative to normal c-abl tyrosine kinase. Hematopoietic progenitors isolated from CML patients in the chronic phase contain a constitutively tyrosine-phosphorylated protein that migrates at 62 kDa by SDS-PAGE and associates with the p120 ras GTPase-activating protein (GAP). We have purified p62(dok) from a hematopoietic cell line expressing p210(bcr-abl). p62(dok) is a novel protein with features of a signaling molecule. Association of p62(dok) with GAP correlates with its tyrosine phosphorylation. p62(dok) is rapidly tyrosine-phosphorylated upon activation of the c-Kit receptor, implicating it as a component of a signal transduction pathway downstream of receptor tyrosine kinases.

The secretome represents the set of proteins secreted into the extracellular space of cells. These proteins have been shown to play a major role in cell-cell communication. For example, recent observations revealed the presence of diffusible factors with proliferative properties in the secretome of cancer cells. Thus, a qualitative and quantitative analysis of the secretome could lead to the identification of these factors and consequently to the development of new therapeutic strategies. Here, we provide an automated simple and effective strategy to identify novel targets in the secretome of specifically treated cells using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Furthermore, we explore the supportive role of mass spectrometry (MS) in the development of functional assays of identified secreted target molecules. Simplicity is achieved by growing cells in medium free of serum, which eliminates the need to remove the most abundant serum proteins and at the same time reduces disturbing matrix effects. Upon identification of these factors, their validation and characterization will follow. Moreover, this approach can also lead to the identification of proteins abnormally secreted, shed, or oversecreted by cells as response to a stimulus. Furthermore, we also discuss the problems that one may encounter. Finally, we discuss the broad application of automated MS-based proteomics, particularly in cancer research, highlighting new horizons for the use of MS.

SUMMARY. The purposes of the present work were to identify the initial characteristics associated with long-term survival in chronic granulocytic leukaemia (CGL) and to analyse the accuracy of prognostic models in identifying long-term survivors. 813 Philadelphia (Ph) chromosome-positive, nonblastic CGL patients from six American and European institutions, the majority treated conventionally, with a minimum follow-up < 10 years, were studied. Stepwise logistic regression was performed to ascertain the association between the initial clinicohaematological variables and survival ≤8 years, and a prognostic index was derived. The usefulness of both Sokal's and the new prognostic index to identify long-term survivors was assessed by calculating their positive and negative predictive accuracies, sensitivity and specificity. Median survival of the series was 45 months (range 1-255), with 784 patients (96.4%) having died and 109 (13.4%) surviving 8 years or longer. Younger age, smaller spleen, platelets ≤600 × 109/I, and lower blood blast percentage were associated with survival ≤8 years; platelets ≤ 600 × 109/I and lower blood blast percentage were the predictive factors in patients 50 years old or younger. Two-thirds of long survivors belonged to Sokal's low-risk group, but the positive predictive accuracy and specificity for prolonged survival of Sokal's index were very low. This was also the case for the new predictive index. In 366 patients with information on the presence or not of additional karyotypic abnormalities at diagnosis, younger age, platelets ≤ 600 × 109/I, lower blood blast percentage, and absence of additional cytogenetic abnormalities were associated with survival ≤8 years. The addition of the cytogenetic data improved the positive predictive accuracy and specificity of the model, albeit modestly. We conclude that, although most CGL long survivors show favourable prognostic features at presentation, clinicohaematological data do not allow a precise definition of such a subpopulation.

The most primitive hematopoietic stem cell (HSC)/progenitor cell (PC) population reported to date is characterized as being Lin−CD34+CD38−CD90+CD45R. We have a long-standing interest in comparing the characteristics of hematopoietic progenitor cell populations enriched from normal subjects and patients with chronic myelogenous leukemia (CML). In order to investigate further purification of HSCs and for potential targetable differences between the very primitive normal and CML stem/PCs, we have phenotypically compared the normal and CML Lin−CD34+CD38−CD90+CD45RA− HSC/PC populations. The additional antigens analyzed were HLA-DR, the receptor tyrosine kinases c-kit and Tie2, the interleukin-3 cytokine receptor, CD33 and the activation antigen CD69, the latter of which was recently reported to be selectively elevated in cell lines expressing the Bcr-Abl tyrosine kinase. Notably, we found a strikingly low percentage of cells from the HSC/PC sub-population isolated from CML patients that were found to express the c-kit receptor (

In comparing gene expression of normal and CML CD34+ quiescent (G0) cell, 292 genes were downregulated and 192 genes upregulated in the CML/G0 Cells. The differentially expressed genes were grouped according to their reported functions, and correlations were sought with biological differences previously observed between the same groups. The most relevant findings include the following. (i) CML G0 cells are in a more advanced stage of development and more poised to proliferate than normal G0 cells. (ii) When CML G0 cells are stimulated to proliferate, they differentiate and mature more rapidly than normal counterpart. (iii) Whereas normal G0 cells form only granulocyte/monocyte colonies when stimulated by cytokines, CML G0 cells form a combination of the above and erythroid clusters and colonies. (iv) Prominin-1 is the gene most downregulated in CML G0 cells, and this appears to be associated with the spontaneous formation of erythroid colonies by CML progenitors without EPO.

Nonparametric maximum likelihood estimation of the probability of failing from a particular cause by time t in the presence of other acting causes (i.e., the cause-specific failure probability) is discussed. A commonly used incorrect approach is to take 1 minus the Kaplan-Meier (KM) estimator (1 – KM), whereby patients who fail of extraneous causes are treated as censored observations. Examples showing the extent of bias in using the 1-KM approach are presented using clinical oncology data. This bias can be quite large if the data are uncensored or if a large percentage of patients fail from extraneous causes prior to the occurrence of failures from the cause of interest. Each cause-specific failure probability is mathematically defined as a function of all of the cause-specific hazards. Therefore, nonparametric estimates of the cause-specific failure probabilities may not be able to identify categorized covariate effects on the cause-specific hazards. These effects would be correctly identified ...

BACKGROUND In a prospective randomized manner, this study evaluated the effect of adjuvant chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone; CHOP) in patients with Stage I non-Hodgkin lymphoma (NHL) who have achieved a complete response (CR) after radiation therapy (RT). METHODS Forty-four patients with clinical or pathologic Stage I intermediate-grade or low-grade NHL were randomized to receive regional RT alone (median dose, 40 Gy) or regional RT followed by six cycles of CHOP chemotherapy. There were no differences in clinical and pathologic characteristics between the two treatment groups. RESULTS The median follow-up was 7 years (range, 2-10 years). The actuarial relapse-free survival (RFS) rate for the RT plus CHOP group at 7 years was 83% compared with 47% (P < 0.03) for the RT-alone group. The overall survival (OS) for the two groups was 88% and 66%, respectively (P = 0.2). In patients with intermediate-grade NHL, the 7-year actuarial RFS for RT and CHOP was 86% compared with 20% for RT alone (P = 0.004). The corresponding actuarial survival rates were 92% and 47%, respectively (P = 0.08). In patients with low-grade histologic findings, the addition of adjuvant CHOP did not improve RFS (P = 0.6) or OS. All relapses in this study were at sites remote from the initially involved areas, and in 5 of 11 patients (45%), there were recurrences 5 years or longer after initial treatment. CONCLUSIONS This study showed that adjuvant CHOP chemotherapy significantly improves RFS in patients with Stage I intermediate-grade NHL who achieve a CR after regional-field RT. The chemotherapeutic regimen favorably affected their probability of survival.

Despite recent important advances in our understanding of the molecular and biological abnormalities in chronic myelogenous leukemia (CML) this new knowledge has not yet led to significant improvements in treatment. We have reviewed what is known and still unknown about some of the important properties of normal and leukemic stem cells and later progenitor cells that may be relevant to developing improved treatment strategies in the future. Clinical observations and experimental evidence strongly suggest that the major expansion of the CML population takes place in the intermediate and later maturation compartments rather than in the stem cell or early progenitor cell compartments. The expansion occurs slowly, probably taking several years to reach a trillion or more cells, at which time clinical symptoms begin to develop. The maturing leukemic progenitors do not have an increased proliferative rate, but they undergo one or more additional divisions and also live longer than comparable normal progenitors. Although no quantitative assay system is available to study the ultimate proliferative potential of human stem cells, indirect evidence suggests that the behavior of leukemic stem cells is not greatly different from that of normal stem cells. One important difference is that the leukemic stem cells (or early progenitor cells) do not curtail cell production until marrow cell densities are reached that are substantially higher than those at which normal stem cells cease production. Based on these and other considerations a possible future therapeutic strategy is suggested. Any successful treatment program for CML will probably depend on the inclusion of some type of specific drug(s) that will selectively affect leukemic progenitors.(ABSTRACT TRUNCATED AT 250 WORDS)

Activating mutations in the Kit receptor tyrosine kinase are associated with gastrointestinal stromal tumor (GIST). Imatinib inhibits Kit and is front-line therapy for GIST. However, imatinib most often elicits a partial response or stable disease, and most GIST patients who initially respond to imatinib eventually acquire resistance. Thus, improved treatment strategies for GIST are needed. We investigated the role of Src family kinases (SFK) in tumorigenesis in a mouse model of human GIST. The SFKs Src and Lyn were active in GIST, and surprisingly, imatinib treatment stimulated their phosphorylation/activation. We show that integrin signaling activates focal adhesion kinase and, consequently, SFKs in GIST and that imatinib enhances integrin signaling, implying a role for the extracellular matrix and integrin signaling in tumor maintenance and imatinib resistance. Dasatinib, an inhibitor of SFKs and Kit, inhibited SFK and focal adhesion kinase activation in GIST but also inhibited Kit and Kit-dependent downstream signaling pathways including phosphoinositide 3-kinase and mitogen-activated protein kinase, but not signal transducer and activator of transcription (STAT) signaling. Whereas dasatinib and imatinib alone both produced a minimal histopathologic response, combination therapy improved their efficacy, leading to increased necrosis in GIST. These results highlight the importance of SFK and STAT signaling in GIST and suggest that the clinical efficacy of imatinib may be limited by the stimulation of integrin signaling. Mol Cancer Res; 8(9); 1271–83. ©2010 AACR.

Previous studies by others using metabolic labeling, cell lysis, and immunoprecipitation have reported elevated levels of p53 protein in blast cells derived from patients with acute lymphoblastic leukemia (ALL) and acute myeloblastic leukemia (AML), whereas p53 protein was not detected in normal light-density bone marrow cells. In this report, using the same detection methods, we confirm the negligible expression of p53 protein in normal light density marrow cells. However, we find clearly significant levels of p53 protein expression in enriched normal human marrow blast populations. Furthermore, using a panel of p53 specific monoclonal antibodies, we find the p53 protein constitutively synthesized by normal marrow blasts has the immunologic phenotype identified by PAb240 that reportedly recognizes a common conformational- dependent epitope on mutant p53. We have also found that the p53 immunologic subclass identified by PAb240 exists in normal human circulating lymphocytes either resting, serum starved, or PHA activated. In summary, it is clear that (1) normal marrow blast populations provide the appropriate control for assessing the levels of p53 protein expression in leukemic blast cells; and (2) PAb240 cannot be used to distinguish p53 mutated at the DNA level from normal p53 in fresh human hematopoietic cells.

To achieve a high percentage of durable complete remissions (CR) and prolonged survivals and reduce toxicity in patients with early-stage and intermediate-stage Hodgkin's disease, a randomized trial of four cycles of mech-Iorethamine, vincristine, procarbazine, and prednisone (MOPP) versus four cycles of thiotepa, bleomycin, and vinblastine (TBV) combined with regional radiation therapy (RT) was conducted. For MOPP and RT, the CR percentage was 98% (60 of 61), and at 5 years, the percentage of patients in CR was 90%, with freedom from progression of 89% and overall survival of 91%. For TBV and RT, the CR percentage was 93% (55 of 59), with a 5-year duration of CR of 83%, freedom from progression of 81%, and overall survival of 91% (P > 0.15). The median follow-up was 65 months (range, 7 to 96 months). For 27 patients with clinical Stage IIIA, the CR percentage for MOPP and RT was 75% (12 of 16), with 1 relapse and 4 deaths. For TBV and RT, the CR percentage for clinical Stage IIIA was 73% (8 of 11) with 2 relapses and 2 deaths. Short-term toxicity except for transient leukopenia was less for TBV and RT than for MOPP and RT. Good results are achievable with combined treatment without excessive toxicity. Cancer 1992; 69:1052–1060.

Numerous reports suggest that allogeneic bone marrow transplantation prolongs the survival of adult patients with acute myelogenous leukemia (AML) in first remission. However, it is unclear how many such patients actually undergo this procedure.We reviewed the case records of 350 consecutive adult patients with AML treated with chemotherapy at a single institution from 1979 (when the policy of offering allogeneic transplantation to all such patients in first remission was introduced) through 1990. The criteria for exclusion before transplantation included age greater than 40 and, beginning in 1984, a diagnosis of acute promyelocytic leukemia.One hundred forty-two patients (41 percent of the study population) were 40 years of age or under. HLA testing was performed for 120 of these patients (85 percent). Sixty-seven patients (47 percent) had an HLA-identical sibling as a potential donor. One hundred three patients (73 percent) entered remission during treatment according to one of five chemotherapy protocols. Of the 52 patients who both entered remission and had an HLA match, 30 underwent transplantation while they were in first remission. These 30 patients constituted 21 percent of all study patients 40 years old or under, 29 percent of all patients 40 or under who entered remission, 45 percent of all patients with an HLA match, 58 percent of all patients who had both a remission and a match, and 9 percent of all patients treated according to a protocol. Among patients with a match who did not undergo transplantation, those with primary refractory disease were the largest subgroup.These findings suggest that allogeneic bone marrow transplantation is performed in less than 60 percent of adult patients with AML who are potentially eligible for the procedure.

We report the design, synthesis, and structure-activity relationship (SAR) of a series of novel pyrido[2,3-d]pyrimidin-7-one compounds as potent Abl kinase inhibitors. We evaluate their specificity profile against a panel of human recombinant kinases, as well as their biological profile toward a panel of well-characterized cancer cell lines. Our study reveals that substitutions in the 3- and 4-positions of the phenylamino moiety lead to improved potency and improved selectivity both in target-based and cell-based assays. Altogether, our results provide an insight into the SAR of pyrido[2,3-d]pyrimidin-7-ones for the development of drug candidates with improved potency and selectivity for the targeted treatment of CML.

Imatinib mesylate induces complete cytogenetic responses in patients with chronic myeloid leukemia (CML), yet many patients have detectable BCR-ABL transcripts in peripheral blood even after prolonged therapy. Bone marrow studies have shown that this residual disease resides within the stem cell compartment. Quiescence of leukemic stem cells has been suggested as a mechanism conferring insensitivity to imatinib, and exposure to the Granulocyte-Colony Stimulating Factor (G-CSF), together with imatinib, has led to a significant reduction in leukemic stem cells in vitro. In this paper, we design a novel mathematical model of stem cell quiescence to investigate the treatment response to imatinib and G-CSF. We find that the addition of G-CSF to an imatinib treatment protocol leads to observable effects only if the majority of leukemic stem cells are quiescent; otherwise it does not modulate the leukemic cell burden. The latter scenario is in agreement with clinical findings in a pilot study administering imatinib continuously or intermittently, with or without G-CSF (GIMI trial). Furthermore, our model predicts that the addition of G-CSF leads to a higher risk of resistance since it increases the production of cycling leukemic stem cells. Although the pilot study did not include enough patients to draw any conclusion with statistical significance, there were more cases of progression in the experimental arms as compared to continuous imatinib. Our results suggest that the additional use of G-CSF may be detrimental to patients in the clinic., Author Summary Imatinib mesylate (Gleevec) is currently the standard treatment for chronic myeloid leukemia (CML) and elicits a large reduction in leukemic cell burden in most patients. However, strong evidence suggests that imatinib does not cure the disease; approximately 20% of patients relapse within three years, and discontinuation of imatinib therapy often leads to a rebound of the leukemic cell burden. Laboratory studies have suggested that there exists a subpopulation of “quiescent” leukemia cells (i.e., cells that do not divide) that may be insensitive to imatinib treatment. It has been postulated that the disease outcome may be improved by administering imatinib in conjunction with the Granulocyte-Colony Stimulating Factor (G-CSF), a growth factor which “wakes up” the quiescent stem cells and sensitizes them to imatinib. In this study, we design a novel mathematical model of stem cell quiescence to investigate the treatment response to imatinib and G-CSF. We find that adding G-CSF to an imatinib treatment protocol leads to observable effects only if the majority of leukemic stem cells are quiescent. Our model also predicts that adding G-CSF leads to a higher risk of resistance, since it increases the number of leukemic stem cell divisions and thus the probability of acquiring a resistance mutation.

The role of adjuvant radiation therapy (RT) in the management of advanced-stage Hodgkin's disease (HD) was analyzed in 222 patients who attained a complete remission (CR) with alternating chemotherapy combinations. Mechlorethamine, vincristine, procarbazine, and prednisone/doxorubicin, bleomycin, vinblastine, and dacarbazine (MOPP/ABVD) or MOPP/ABV alternating with the lomustine, melphalan, and vindesine combination (MOPP/ABV/CAD) were similarly effective in inducing a CR in 222 of 270 (83%) patients. These patients were scheduled to receive consolidative RT to bulky disease or other critical sites of initial nodal involvement to a total dose of 2,000 cGy, with an optional additional boost of 1,000 cGy. However, only 125 (56%) patients received radiation to all initial nodal sites of disease. In 69 (31%) patients, only selected nodal sites were included in the radiation fields, and 28 (13%) did not receive any RT. Of the 222 CR patients, 42 (19%) relapsed during a median follow-up period of 6.5 years (range, 2 to 15 years). Of these, 26 (62%) patients relapsed exclusively in unirradiated nodal sites, six (14%) within irradiated sites, and 10 (24%) both within and outside irradiated fields. The actuarial 10-year relapse-free survival (RFS) and overall survival (OS) for patients receiving radiation to all initially involved nodal sites were 89% and 94%, respectively, compared with 68% and 71% (P less than .0001) for patients who had only partial or no RT. Cox proportional hazards regression analysis showed that RT to all sites of initial disease was the most significant independent covariate (P less than .005) affecting RFS and OS. These data demonstrate that residual microscopic disease is relatively frequent in patients with apparent CR after alternating combination chemotherapy, and that irradiation of all sites of initial nodal involvement decreases relapse and improves survival in advanced-stage HD.

The molecular events that allow for clonal expansion of the malignant population in chronic myelogenous leukemia (CML) are poorly understood. Recent experiments in transgenic mice suggest a close temporal relationship between expression of the aberrant protein and manifestation of a hematologic neoplasm that resembles CML; tracing the same phenomenon in humans has not been possible. We studied a patient who underwent autologous bone marrow harvest after completion of chemotherapy and radiation therapy for advanced stage Hodgkin's disease. At the time of harvest his peripheral blood counts and bone marrow were morphologically normal. Sixteen months later he developed the clinical manifestations of CML. Detailed molecular evaluation of the harvested marrow showed that a small number of cells contained the Philadelphia chromosome. The time interval required for expansion of the malignant clone, as suggested by this particular patient, was at least 16 months although it is recognized that this figure may be variable.

Ten patients with myeloid leukemias were treated in a phase I trial with escalating doses of mouse monoclonal antibody (mAb) M195, reactive with CD33, a glycoprotein found on myeloid leukemia blasts and early hematopoietic progenitor cells but not on normal stem cells. M195 was trace-labeled with iodine-131 (131I) to allow detailed pharmacokinetic and dosimetric studies by serial sampling of blood and bone marrow and whole-body gamma-camera imaging. Total doses up to 76 mg were administered safely without immediate adverse effects. Absorption of M195 onto targets in vivo was demonstrated by biopsy, pharmacology, flow cytometry, and imaging; saturation of available sites occurred at doses greater than or equal to 5 mg/m2. The entire bone marrow was specifically and clearly imaged beginning within hours after injection; optimal imaging occurred at the lowest dose. Bone marrow biopsies demonstrated significant dose-related uptake of M195 as early as 1 hour after infusion in all patients, with the majority of the dose found in the marrow. Tumor regressions were not observed. An estimated 0.33 to 1.0 rad/mCi 131I was delivered to the whole body, 1.1 to 6.1 rad/mCi was delivered to the plasma, and up to 34 rad/mCi was delivered to the red marrow compartment. 131I-M195 was rapidly modulated, with a majority of the bound immunoglobulin G (IgG) being internalized into target cells in vivo. These data indicate that whole bone marrow ablative doses of 131I-M195 can be expected. The rapid, specific, and quantitative delivery to the bone marrow and the efficient internalization of M195 into target cells in vivo also suggest that the delivery of other isotopes such as auger or alpha emitters, toxins, or other biologically important molecules into either leukemia cells or normal hematopoietic progenitor cells may be feasible.

PURPOSE: Small non-cleaved-cell lymphoma (SNCL) "Burkitt's type," a rapidly growing lymphoma, has been rare among adults in the United States, but has greatly increased in incidence with the acquired immunodeficiency syndrome epidemic. This report details the results of treatment of adult SNCL with a series of protocols originally designed for the treatment of acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: Between July 1973 and May 1987, 29 adults with newly diagnosed SNCL were treated at Memorial Hospital with intensive chemotherapy originally designed for ALL: the cyclophosphamide L-2, L-10, L-17, and L-20 protocols. Nine patients had positive serologies for human immunodeficiency virus (HIV) infection. One patient with all measurable disease resected was not evaluable for response. RESULTS: Sixteen of 28 evaluable patients (57%) achieved a complete remission with treatment. With follow-up as long as 153 months (median, 47 months), 50% of all patients and 59% of patients with negative or unknown HIV serologies have survived and are probably cured. Patients with an initial serum lactic acid dehydrogenase (LDH) level of greater than 500 U/L had a significantly shortened survival as compared with those with a lower serum LDH. Other pretreatment patient characteristics associated with a shortened survival of borderline statistical significance were high National Cancer Institute stage (C, D) and bone marrow involvement. These results are similar to those for ALL and lymphoblastic lymphoma and are comparable to those for American SNCL in the literature. CONCLUSIONS: Approximately one half of adults with SNCL are curable with intensive chemotherapy. More intensive chemotherapy with hematopoietic growth factor and/or autologous bone marrow or peripheral stem cell support may increase curability.

We examined the effect of tamoxifen (Tmx), verapamil, and daunorubicin (DNR) in two cell lines that displayed the multidrug-resistant (MDR) phenotype and used laser flow cytometry to quantitate intracellular DNR content. In the vinblastine-resistant human lymphoblastic lymphoma cell line CEM-VBL, simultaneous incubation of DNR with Tmx 10 mumol/L or Tmx 50 mumol/L increased intracellular DNR fluorescence in a dose-dependent manner and demonstrated an uptake pattern similar to that seen with DNR and verapamil. Similar results were obtained in the vincristine- resistant human myeloid leukemia cell line HL-60/RV+. Cellular retention of DNR was also measured in both cell lines and results suggested that continuous exposure of the cells to Tmx resulted in higher intracellular DNR content compared with cells resuspended in fresh medium. No effect of Tmx or verapamil was observed in the drug- sensitive parent cell lines CEM or HL-60. Clonogenic experiments were then performed to determine whether Tmx was itself inhibitory to cell growth or whether Tmx potentiated DNR cytotoxicity. Tmx 10 mumol/L did not significantly inhibit either CEM-VBL or HL-60/RV+ cells after a 3- hour exposure followed by culture in methylcellulose. Tmx 50 mumol/L was significantly more inhibitory in both cell lines. However, cells that had been incubated with DNR and Tmx 10 mumol/L demonstrated a marked increment in growth inhibition compared with cells that had been incubated with DNR alone or Tmx 10 mumol/L alone. Based on the data presented here, we suggest that clinical testing of Tmx and DNR be pursued in the setting where MDR may play a role.

Summary Various protocols have been used at Memorial Sloan-Kettering Cancer Center to improve the results of autologous bone marrow transplantation (ABMT) for hematopoietic malignancies. Results suggest that patients who undergo ABMT while in complete remission (after induction or reinduction treatment) do better than those who undergo ABMT in incomplete remission. In patients with relapsed or refractory lymphoma, the addition of etoposide to the total body irradiation/cyclophosphamide conditioning regimen has decreased the relapse rate from 53% to 7%. For patients with refractory or relapsed Hodgkin's disease, the dosages of different drugs can be altered to improve the overall success. Dose escalation of etoposide shows significant promise. Relapse after ABMT and/or toxic complications are the main factors that need to be addressed in the future. Pulmonary toxicity occurs mainly in patients with mediastinal disease. Factors that can decrease relapse rate and toxicity are discussed.

The initial promising results with alternating chemotherapy regimens (mechlorethamine, vincristine, procarbazine, and prednisone/doxorubicin, bleomycin, vinblastine, and dacarbazine [MOPP/ABVD]; lomustine, melphalan, and vindesine [CAD] plus MOPP plus ABV) combined with intermediate-dose radiation therapy (RT) have been sustained with further follow-up; 82.2% of patients (152 of 185) achieved a complete remission (CR), and overall survival is 71.7% +/- 4.4% at 8 years (median follow-up is 55 months among the survivors). No statistically significant differences were found in CR percentage, CR duration, or survival between stages IIB, IIIB, and IV patients. For that reason, stepwise Cox regression analyses to identify the important prognostic factors were performed on overall survival, tumor mortality, freedom from disease progression, and survival following disease progression. Pretreatment characteristics were also tested for association with the probability of achieving CR, CR duration, and death due to other causes. Characteristics that were consistently associated with an independently unfavorable prognosis were low hematocrit, high serum lactic acid dehydrogenase (LDH), age more than 45 years, inguinal node involvement, mediastinal mass greater than .45 of the thoracic diameter, and bone marrow involvement. Patients with two or more unfavorable characteristics were much more likely to fail treatment (median survival, 62.4 months) than those with none or only one unfavorable factor (greater than 95% survival). This striking difference between the low- and high-risk groups remained even if the comparison was restricted to patients less than or equal to 45 years of age. These results provide a basis for selecting the young patients at high risk of failure for more intensive initial treatment with either autologous bone marrow rescue or hematopoietic growth factors.

Thirty-five evaluable patients with hairy cell leukemia (HCL) were treated with recombinant interferon alfa-2a (rIFN-alpha 2a), given at a dose of 3 X 10(6) units (U) intramuscularly (IM) daily for 6 months followed by 3 X 10(6) U IM three times a week for an additional 18 months in a single institution study. All treatment was stopped after 24 months. Sixty-nine percent of patients achieved a partial response, 11% a minor response, and 3% (one patient) had stable disease. Six patients (17%) did not respond to rIFN-alpha 2a. Two patients (6%) achieved a response but later progressed on treatment. A total of 23 patients completed 2 years of treatment and are evaluable for long-term follow-up at a median of 20 months postcompletion of therapy (range 9 to 32 months). Eleven patients (48%) have had progression of their disease at a median of 10 months (range .5 to 25 months) after treatment was discontinued. Statistical analysis of pretreatment patient characteristics did not reveal any factor(s) associated with a high probability of responding to rIFN-alpha 2a; however, analysis of post-treatment variables measured after 2 years of treatment suggested that a low platelet count was associated with a high rate of disease progression. These findings are compared with other published trials using rIFN-alpha 2b, a similar but not identical rIFN preparation. We conclude that while rIFN-alpha 2a has a high overall response incidence, the rate of disease progression after therapy is discontinued approaches 50%, and that a subset of patients can be identified who are at high risk for recurrence after completing 2 years of treatment.

Seventy previously untreated patients with stage II, III, and IV intermediate- or high-grade lymphoma were treated with methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B) between September 1985 and November 1987. Forty-nine of these patients had diffuse large-cell lymphoma (DLCL), and eight of these patients were human immunodeficiency virus (HIV)-positive. Complete responses were achieved in 54% of all patients and 52% of those with DLCL. With follow-up extending to 36 months, 45% of all DLCL patients are alive, and 50% are still living, if the HIV-positive patients are excluded from the analysis. Chemotherapy was quite toxic. Seventy-five percent of patients had severe mucositis, 42% had peripheral neuropathy, 50% required hospitalization, and 54% experienced leukopenia with a WBC count below 1,000/microL. Seven percent (five patients) died of toxicity related to the chemotherapy. Our analysis of prognostic parameters indicated that B symptoms, a performance status below 80, and, to a lesser extent, elevation of serum lactic acid dehydrogenase (LDH) (in HIV-negative DLCL patients) were associated with an inferior survival. Advanced age, sex, and bulky disease were not found to have a statistically significant effect on survival. Our preliminary results indicate that MACOP-B chemotherapy is an effective regimen for high- and intermediate-grade lymphomas. However, the survival for patients with DLCL treated with MACOP-B is no different than that achieved with previous regimens at our institution.

The immunological phenotypes of lymphocytes and myeloma cells in 48 patients with multiple myeloma (MM) were analyzed using a panel of monoclonal antibodies (mAbs). Myeloma cells were positive for OKT10, BL3, PCA1 and BA2. In a few cases, they were also positive for the B cell-associated antigens J5, B1 and I2. Eight of 48 cases had more than 15% J5-positive lymphocytes, and some lymphocytes in MM expressed plasma cell-associated antigens (PCA1, BL3, OKT10), suggesting a possible clonal involvement. These observations demonstrate the heterogeneity of surface antigen expression of myeloma cells and suggest that BL3, PCA1, BA2 and J5 may be useful mAbs for purging myeloma cells from bone marrow for autologous transplantation.

Two cases of Fusarium infection in patients with refractory hematologic malignancies are reported. In one patient septicemia progressed to death in septic shock. Miconazole showed some effect in clearing the lesions. There is some evidence that mycotoxins are related with Fusarium infections since severe myositis occurred in our patient. The other patient had a T-cell lymphoma, undergoing allogeneic bone marrow transplantation. The course was also complicated by Fusarium infection of the skin. This patient died of multiorgan failure. Recent literature on Fusarium is reviewed.

Tyrosine kinases often play pivotal roles in the pathogenesis of cancer and are good candidates for therapeutic intervention and targeted molecular imaging. The precursor synthesis, radiosynthesis, and biological characterization of a fluorine-18 analog of dasatinib, a multitargeted kinase inhibitor, are reported. Compound 5 potently inhibits Abl, Src, and Kit kinases and inhibits K562 and M07e/p210bcr-abl human leukemic cell growth. Using positron emission tomography, we visualized K562 tumor xenografts in mice with [18F]-5.

Purpose: Resistance is commonly acquired in patients with metastatic gastrointestinal stromal tumor who are treated with imatinib mesylate, often due to the development of secondary mutations in the KIT kinase domain. We sought to investigate the efficacy of second-line tyrosine kinase inhibitors, such as sorafenib, dasatinib, and nilotinib, against the commonly observed imatinib-resistant KIT mutations (KITV654A, KITT670I, KITD820Y, and KITN822K) expressed in the Ba/F3 cellular system. Experimental Design: In vitro drug screening of stable Ba/F3 KIT mutants recapitulating the genotype of imatinib-resistant patients harboring primary and secondary KIT mutations was investigated. Comparison was made to imatinib-sensitive Ba/F3 KIT mutant cells as well as Ba/F3 cells expressing only secondary KIT mutations. The efficacy of drug treatment was evaluated by proliferation and apoptosis assays, in addition to biochemical inhibition of KIT activation. Results: Sorafenib was potent against all imatinib-resistant Ba/F3 KIT double mutants tested, including the gatekeeper secondary mutation KITWK557-8del/T670I, which was resistant to other kinase inhibitors. Although all three drugs tested decreased cell proliferation and inhibited KIT activation against exon 13 (KITV560del/V654A) and exon 17 (KITV559D/D820Y) double mutants, nilotinib did so at lower concentrations. Conclusions: Our results emphasize the need for tailored salvage therapy in imatinib-refractory gastrointestinal stromal tumors according to individual molecular mechanisms of resistance. The Ba/F3 KITWK557-8del/T670I cells were sensitive only to sorafenib inhibition, whereas nilotinib was more potent on imatinib-resistant KITV560del/V654A and KITV559D/D820Y mutant cells than dasatinib and sorafenib.

Regulated phosphorylation by protein tyrosine kinases (PTKs) such as c-Abl, is critical to cellular homeostasis. In turn, once deregulated as in the Chronic Myeloid Leukemia (CML) fusion protein Bcr-Abl, PTKs can promote cancer onset and progression. The dramatic success of the Bcr-Abl inhibitor imatinib as therapy for CML has inspired interest in other PTKs as targets for cancer drug discovery. Here we report a novel PTK activity and inhibition screening method using hydrogel-immobilized peptide substrates. Using acrylate crosslinkers, we tether peptides via terminal cysteines to thiol-presenting hydrogels in 96-well plates. These surfaces display low background and high reproducibility, allowing semi-quantitative detection of peptide phosphorylation by recombinant c-Abl or by Bcr-Abl activity in cell extracts using traditional anti-phosphotyrosine immunodetection and chemifluorescence. The capabilities of this assay were demonstrated by performing model screens for inhibition with several commercially available PTK inhibitors and a collection of pyridopyrimidine Src/Abl dual inhibitors. This assay provides a practical method to measure the activity of a single kinase present in a whole cell lysate with high sensitivity and specificity as a valuable means for efficient small molecule screening.