The presence of the Rb c-box peptide in the cytoplasm inhibits p210bcr-abl transforming function

In order to test if the carboxyl terminal polypeptide of the Retinoblastoma (Rb) tumor suppressor protein, could be used to suppress the growth factor-independent growth phenotype of p210bcr-abl positive myeloid cells, we introduced a truncated form of the 3' end of the Rb cDNA encoding its last 173 amino acid residues (Rb C-box) which localize into the cytoplasm where the p210bcr-abl transforming protein is found, into myeloid cells (32D) which depends on the p210bcr-abl protein for IL3 growth factor-independent growth (32D-p210). The expression of the plasmid vectors carrying the Rb C-box cDNAs was shown to inhibit the abl tyrosine specific protein kinase activity of the p210(bcr-abl) oncoprotein and to suppress the IL3-independent growth phenotype of the 32D-p210 cells. The Rb C-box polypeptides did not suppress the growth of the untransfected 32D parental cell line in methylcellulose in the presence of IL3-conditioned medium. These results suggest that the cytoplasmic localization of the p210(bcr-abl) allows it to escape the effect of intranuclear proteins such as Rb which negatively regulate the p145(c-abl) kinase.

Peptide containing the BCR oligomerization domain (AA 1-160) reverses the transformed phenotype of p210bcr-abl positive 32D myeloid leukemia cells

We first showed that the introduction of a bcr-abl transcription unit into the 32D murine myeloid cell line (P210bcrabl32D) converts this cell line from an IL3 dependent cell line to an IL3 growth independent cell line. We next cloned a fragment of the bcr-abl cDNA, which codes for the bcr oligomerization domain and neighboring regions. To test for a transformation inhibitory effect of this oligomerization inhibitory peptide transcription unit on the p210bcr-abl mediated IL3 independent growth of the P210bcrabl32D cell line, we transiently co-electroporated into the growth factor dependent 32D cells, mixtures of plasmids which contained varying ratios of the plasmid expression vectors for the bcr oligomerization inhibitory peptide along with a smaller amount of the plasmid expression vector for the full length p210bcr-abl. (The P210bcr-abl protein converts the 32D from a growth factor dependent into a growth factor independent cell line.) We then showed that the oligomerization domain containing fragment from the bcr and bcr-abl proteins, can be used to inhibit the IL3 independent growth of p210bcr-abl positive 32D cells. These studies may be of eventual interest for those investigators whose goal is to design molecular therapeutic approaches to CML based on the use of peptidomimetic chemical functionalities, which mimic the structure and the inhibitory binding properties of the oligomerization domain containing fragment so as to inhibit the transforming function of the P210bcr-abl oncoprotein.

Prevention of late effects of irradiation lung damage by manganese superoxide dismutase gene therapy

Organ and tissue damage caused by ionizing irradiation is directly related to volume irradiated, total dose and dose rate. The acute effects are in part mediated by cellular activation of early response genes, including those for transcriptional activators of genes for humoral cytokines. In the lung, as in other organs, recovery from the acute effects of ionizing irradiation does not always correlate with prevention of the critical late effects, including fibrosis, which contribute to organ failure. An interventional technique by which to protect normal organs from the late effects of irradiation has remained elusive. We now demonstrate that overexpression of a transgene for human manganese superoxide dismutase (MnSOD) delivered by plasmid-liposome, or adenovirus to the lungs of C57BL/6J or Nu/J mice, respectively, before irradiation exposure, decreases the late effects of whole lung irradiation (organizing alveolitis/fibrosis). These data provide a rational basis for the design of gene therapy approaches to organ protection from irradiation damage.

Effect of rhBMP-2 on the osteogenic potential of bone marrow stromal cells from an osteogenesis imperfecta mouse (oim)

To understand whether osteogenesis imperfecta (OI) could result from defective differentiation of osteoprogenitor cells, we investigated the osteogenic potential of bone marrow stromal cells from a mouse model of human OI (oim). Bone marrow was flushed from the femurs and tibias of oim and normal littermates using a syringe with Dulbecco's modified Eagle's medium, and cells were allowed to adhere to flasks. Adherent cells were trypsinized and passaged weekly at a 1:4 split. The established stromal cells were assessed for collagen synthesis, alkaline phosphatase, and osteocalcin production in the presence or absence of rhBMP-2. The stromal cells were also assessed for mineralization by Von-Kossa staining and for exogenous gene transfer using adeno-lacZ and a retroviral vector. The bone marrow stromal cells from oim mice synthesized alpha 1(I) homotrimers as expected, whereas the stromal cells from the normal littermates synthesized alpha 1(I)2 alpha 2(I) heterotrimers. The bone marrow stromal cells exhibited low levels of alkaline phosphatase activity under basal conditions: upon treatment with rhBMP-2, the level of the alkaline phosphatase activity increased approximately 40-fold. Cytochemical staining of the cells confirmed the expression of alkaline phosphatase by the oim stromal cells and its augmentation by rhBMP-2. Osteocalcin production in the stromal cells was also enhanced approximately threefold by rhBMP-2. oim stromal cells grown in the presence of beta-glycerophosphate and ascorbic acid demonstrated Von-Kossa-positive solid deposits after 3 weeks in culture. Ten days after infection with adeno-lacZ, approximately 70% of oim stromal cells expressed the transgene product, and after infection with a retrovirus, approximately 20% of the cells expressed the transgene. These data indicate that bone marrow stromal cells, have osteogenic potential, and also the potential to be transduced with exogenous genes. Under basal conditions, however, the stromal cells from oim mice exhibited significantly lower levels of alkaline phosphatase activity than their normal littermates.

Potential role of bcr-abl in the activation of JAK1 kinase

To study the oncogenic role of the p210(bcr-abl) fusion protein in chronic myelogenous leukemia cells, we generated a mouse cell line that was stably transfected with and overexpressed the human p210(bcr-abl) fusion protein. We then looked for phosphorylation activation of the Janus-activated kinase (JAK) family of tyrosine-specific protein kinases by the p210(bcr-abl) fusion protein. We found that JAK1, which has been shown by others to be associated with the IFN-alpha and -gamma plasma membrane receptors, was phosphorylated to a much greater degree in cells containing the p210(bcr-abl) fusion protein than was the case in the original, untransfected cell line. In contrast, no phosphorylation of the JAK2 kinase, which is associated with the IFN-gamma but not IFN-alpha receptor, was observed either with or without p210(bcr-abl) protein. A substrate of JAK1, STAT1 (signal transducers and activators of transcription 1), was found to be phosphorylated in cells containing overexpressed p210(bcr-abl) fusion protein. These results indicate that the presence of the p210(bcr-abl) protein kinase within a cell is associated with phosphorylation of the JAK1 kinase and its substrate STAT1.

Hematopoietic stem cell compartment: acute and late effects of radiation therapy and chemotherapy

The bone marrow is an important dose-limiting cell renewal tissue for chemotherapy, wide-field irradiation, and autologous bone marrow transplantation. Over the past 5-10 years a great deal has been discovered about the hematopoietic stem cell compartment. Although the toxicity associated with prolonged myelosuppression continues to limit the wider use of chemotherapy and irradiation, ways are being discovered to circumvent this toxicity such as with the increasing use of cytokines. This review describes what is known of how chemotherapy and irradiation damage stem cells and the microenvironment, how cytokines protect hematopoietic cells from radiation damage and speed marrow recovery after chemotherapy or marrow transplantation, and how various types of blood marrow cells contribute to engraftment and long-term hematopoiesis after high doses of cytotoxic agents and/or total body irradiation.

Effects of macrophage colony stimulating factor and granulocyte-macrophage colony stimulating factor on osteoclastic differentiation of hematopoietic progenitor cells

Although the hematopoietic origin of the osteoclast is generally accepted, the precise phenotype of the progenitor and the regulation of its differentiation are unclear. This study compares proliferation and differentiation of progenitors in response to macrophage colony stimulating factor (M-CSF) and granulocyte macrophage colony stimulating factor (GM-CSF). Nonadherent progenitor cells from murine long-term bone marrow cultures (LTBMC) (as a source of osteoclast progenitors) demonstrated a significant proliferative response to M-CSF. In addition, M-CSF increased the number of multinucleated cells, only a small percent of which (14-16%) were tartrate-resistant, acid phosphatase (TRAP)-positive. In contrast, cells cultured with GM-CSF generated more TRAP-positive multinucleated cells even at concentrations less stimulatory of proliferation than M-CSF. The osteoclast phenotype of these multinucleated cells was also assessed by ultrastructural characterization of ruffled borders in association with bone fragments. The bone-active hormone 1,25-dihydroxyvitamin D3 inhibited the proliferation of this subset of progenitor cells in the presence of M-CSF or GM-CSF. All of these results show effects on progenitors in the absence of the stromal cell microenvironment in this system. These results provide evidence for a divergence in the biological responsiveness of osteoclast progenitor cells to M-CSF compared with GM-CSF; they support the notion that M-CSF has a "priming" effect on osteoclast progenitors whose subsequent differentiation to osteoclastic multinucleated cells is promoted by GM-CSF.

Quantitation of murine hematopoietic stem cells in vitro by limiting dilution analysis of cobblestone area formation on a clonal stromal cell line

Murine hematopoietic stem cells with varying proliferative capacity can be assayed by limiting dilution analysis of "cobblestone area" (CA) formation on stromal layers in microlong-term bone marrow cultures. Cobblestone area forming cell (CAFC) frequency determined at early time points (day 7) correlates with mature stem cells measured as day 8 CFU-S, whereas CAFC frequency determined at day 28 correlates more closely with long-term marrow repopulating ability. Here we report a modification of the CAFC assay in which a clonal bone marrow stromal cell line, GB1/6, is substituted for fresh marrow-derived stromal layers. This modification simplifies the initial culture setup, eliminates inhomogeneities in the stromal layer and reduces the need for mice. Normal bone marrow CAFC frequencies were the same for both types of stromal cell underlayer, demonstrating the ability of a clonal cell line to completely replace the heterogeneous microenvironment of fresh stroma for in vitro stem cell support.

Adipogenesis in a myeloid supporting bone marrow stromal cell line

The bone marrow stroma contains pre-adipocyte cells which are part of the hemopoietic microenvironment. Cloned stromal cell lines differ both in their ability to support myeloid and lymphoid development and in their ability to undergo adipocyte differentiation in vitro. These processes have been examined in the +/+2.4 murine stromal cell line and compared to other stromal and pre-adipocyte cell lines. In long-term cultures, the +/+2.4 stromal cells support myeloid cell growth, consistent with their expression of macrophage-colony stimulating factor mRNA. However, despite the presence of mRNA for the lymphoid supportive cytokines interleukins 6 and 7, +/+2.4 cells failed to support stromal cell dependent B lineage lymphoid cells in vitro, suggesting that these stromal cells exhibit only a myelopoietic support function. The +/+2.4 cells differentiate into adipocytes spontaneously when cultured in 10% fetal bovine serum. The process of adipogenesis can be accelerated by a number of agonists based on morphologic and gene marker criteria. Following induction with hydrocortisone, methylisobutylxanthine, indomethacin, and insulin in combination, a time dependent increase in the steady state mRNA and enzyme activity levels of the following adipocyte specific genes was observed: adipocyte P2, adipsin, CAAT/enhancer binding protein, and lipoprotein lipase. In contrast, adipogenesis was accompanied by a slight decrease in the signal intensity of the macrophage-colony stimulating factor mRNA level, similar to that which has been reported in other bone marrow stromal cell lines. These data demonstrate that although the lympho-hematopoietic support function of pre-adipocyte bone marrow stromal cell lines is heterogeneous, they share a common mechanism of adipogenesis.

Humoral and cell surface interactions during gamma-irradiation leukemogenesis in vitro

Gamma-irradiation of plateau phase cultures of the clonal murine bone marrow stromal cell line D2XRII followed by cocultivation of a clonal interleukin 3 (IL-3) (granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent hematopoietic progenitor cell line FDC-P1JL26 results in a significant increase in "cobblestone islands" of attachment and emergence of subclonal factor-independent malignant sublines. Biochemical purification of conditioned medium from irradiated D2XRII cells yielded a 75,000-dalton glycoprotein termed leukemogenic stromal factor (LSF) that was neutralized by a polyclonal antiserum to murine macrophage colony-stimulating factor (M-CSF). A monoclonal antibody to the murine M-CSF receptor (c-fms) neutralized the biological activity of this molecule in a manner comparable to its effect on recombinant human or murine M-CSF. FDC-P1JL26 parent cells were positive for Ly5, MEL-14, mGR, VLA-4, PGP-1 (CD44), and Thy1.2. After culture in LSF, Thy1.2, MEL-14, and mGR became undetectable; however, significant cell surface MAC-1 antigen and c-fms (M-CSF receptor) were expressed. Neither line was positive for Ly6, Ly22, I-CAM-1, or B220 antigen. LSF-precultured FDC-P1JL26 cells transferred as single cells to microwell culture with 5000-cGy-irradiated D2XRII cells revealed a 60-fold increase in frequency of cobblestone island formation and evolution of factor-independent subclones compared to the parent line. Both parent and LSF-precultured cells became factor independent at a 100-fold lower frequency if kept in suspension in LSF in the absence of stromal cells. Antiserum to M-CSF or monoclonal antibody to the murine M-CSF receptor (c-fms) did not inhibit or displace cobblestone island formation by either clone of FDC-P1 on irradiated stromal cells indicating a mechanism of binding not involving the M-CSF receptor. However, anti-serum to the M-CSF receptor inhibited growth of one factor-independent subclone. In separate studies, a subclone of IL-3-dependent 32Dc13 cells, expressing the transfected murine c-fms protooncogene but not the parent 32Dc13 cell line or another subclone expressing the transfected gene for the human M-CSF receptor, showed adherence and became factor independent when cocultivated with irradiated D2XRII stromal cells. Thus, irradiated stromal cells bind M-CSF receptor-positive hematopoietic progenitor cells and induce c-fms-dependent factor-independent tumorigenic subclones. The cellular interactions in this model may be relevant to gamma-irradiation leukemogenesis in vivo.

Preirradiation chemotherapy of supratentorial malignant primary brain tumors with intracarotid cis-platinum (CDDP) and i.v. BCNU. A phase II trial

Thirty patients with histologically verified malignant supratentorial gliomas were treated with a preirradiation chemotherapy protocol consisting of two courses of intracarotid (i.c.) CDDP, 90 mg/m2, followed by i.v. BCNU, 200 mg/m2. Side effects from therapy were mild and self-limiting; no irreversible retinal or neurologic toxicity could be attributed to i.c. chemotherapy. Of the 27 patients who completed the chemotherapy portion of the protocol, tumor size on postchemotherapy computed tomography (CT) was decreased by greater than 50% in 13% as compared to the postoperative CT scan; in only 4% was the CT scan unequivocally increased in size. Twenty-five (83%) patients completed the entire protocol. Median time to tumor progression and survival in patients who completed the protocol was 53 (range of 13-130+) and 61 (range of 29-130+) weeks, respectively. Twenty-four percent of patients still have not demonstrated tumor progression at intervals greater than 1 year after diagnosis as judged by clinical and radiographic criteria. Tumor recurrences were always contiguous to the original tumor bed. We conclude that preirradiation chemotherapy may be administered safely and with low morbidity. Further study to determine an optimal timing between chemotherapy and radiation therapy is warranted.

Erythropoietin changes the globin program of an interleukin 3-dependent multipotential cell line

B6SUtA is a factor-dependent murine cell line of adult origin displaying the functional properties of a multipotent hematopoietic stem cell. We analyzed the globin programs of B6SUtA cells undergoing erythroid differentiation in both suspension and clonal cultures. In the absence of added erythropoietin, a small number of hemoglobinized cells were present, and these expressed predominantly embryonic globin. Addition of erythropoietin increased the number and maturation of hemoglobinized cells and led to a preferential augmentation of adult globin. Analysis of individual B6SUtA erythroid bursts showed that embryonic and adult globin can be expressed in cells derived from a single progenitor. Furthermore, by studying globin expression in cultured cells from mouse embryos, we found that the globin programs of B6SUtA cells are similar to those of erythroid progenitors at the period of transition from yolk sac to fetal liver erythropoiesis. Since B6SUtA cells are derived from adult bone marrow and they have the capacity to express embryonic globin, we speculate that the globin locus is not irreversibly modified during development and that adult cells at early stages of erythroid differentiation can transiently express ontogenetically primitive globin programs.

Heterodimeric transforming growth factor beta. Biological properties and interaction with three types of cell surface receptors

Type beta transforming growth factors (TGF) are disulfide-linked homo- and heterodimers of two related polypeptide chains, beta 1 and beta 2. The homodimers TGF-beta 1 and TGF-beta 2 are widely distributed, but the heterodimer TGF-beta 1.2 has been found only in porcine platelets (Cheifetz, S., Weatherbee, J.A., Tsang, M.L.-S., Anderson, J.K., Mole, J.E., Lucas, R., and Massagué, J. (1987) Cell 48, 409-415). Here we characterize the receptor binding and biological properties of TGF-beta 1.2 and compare them with those of TGF-beta 1 and TGF-beta 2. Three types of cell surface receptors previously identified by affinity labeling with 125I-TGF-beta 1 are available for binding to TGF-beta 1.2. These three types of receptors are detected as 65-kDa (type I), 85-95-kDa (type II), and 250-350-kDa (type III) affinity-labeled receptor complexes on electrophoresis gels. They co-exist in many cell types, have high affinity for TGF-beta 1, and varying degrees of affinity for TGF-beta 2. Of the 11 cell lines screened in the present study none showed evidence for additional receptor types that would bind TGF-beta 2 but not TGF-beta 1. In receptor competition studies, TGF-beta 1, TGF-beta 1.2, and TGF-beta 2 competed for binding to type I and type II receptors with a relative order of potencies of 16:5:1 and 12:3:1, respectively, whereas all three forms of TGF-beta were equipotent as ligands for the type III receptors. The three forms of TGF-beta were equally potent at stimulating the biosynthesis of extracellular sulfated proteoglycan in BRL-3A rat liver epithelial cells, a response that presumably involves the type III receptor present in these cells. In contrast, the ability of the three ligands to inhibit the growth of B6SUt-A multipotential hematopoietic progenitor cells which display only type I receptors decreased in the order TGF-beta 1, TGF-beta 1.2, and TGF-beta 2 with a relative potency of 100:30:1. The results indicate that the presence of one beta 1 chain in TGF-beta 1.2 increases (with respect to TGF-beta 2) the biological potency and binding affinity toward receptor types I and II, but the presence of a second beta 1 chain in the dimer is required for full potency.

Blastogenesis of large granular lymphocytes in nonlymphoid organs

High numbers of large granular lymphocytes (LGL) accumulate in the livers and peritoneal cavities of mice during the course of viral infection. Accumulation of natural killer (NK) cells at day 3 postinfection (p.i.) was shown to be radiation-sensitive, implying that proliferation was required for this response. Accumulation occurred in splenectomized mice, indicating that the spleen, known to be an organ for mature NK cell proliferation, was not the major source for liver and peritoneal NK/LGL. Significant percentages (greater than 25%) of the LGL found in the liver and peritoneal cavity following viral infection or interferon induction with poly-inosinic:poly-cytidylic acid were defined morphologically as blasts (large cells with prominent nucleoli and intensely basophilic cytoplasms containing azurophilic granules). Most blast LGL at day 3 p.i. were sensitive to administration of anti-asialo GM1 serum in vivo, were Lyt-2-, and were enriched in populations that lysed NK cell-sensitive targets in vitro, indicating that these were NK/LGL. At day 3 p.i., leukocytes from the liver and peritoneal cavity incorporated 3H-thymidine and bound to and killed NK cell-sensitive targets in single-cell cytotoxicity assays. These data suggest that NK/LGL undergo at least one round of division in the liver and peritoneal cavity during viral infection. In contrast, blast LGL at day 7 p.i. were resistant to in vivo treatments with anti-asialo GM1 serum, were Lyt-2+, and were enriched in populations of cells that killed virus-infected histocompatible targets, indicating that they were cytotoxic T lymphocytes (CTL). These results suggest that both NK/LGL and CTL/LGL are capable of blastogenesis and presumed proliferation at sites of virus infection, providing a means for the in situ augmentation of a host's cell-mediated antiviral defenses.

Doxorubicin chemotherapy in the treatment of soft-tissue sarcoma. Combined results of two randomized trials

In 1978, there were initiated two independent randomized, prospective trials of adjuvant doxorubicin hydrochloride (Adriamycin) following primary therapy for soft-tissue sarcoma. The virtual identity of these two protocols permits their combination for analysis. A total of 75 patients (42 men, 33 women) with soft-tissue sarcoma (stages IIB to IVA) were randomized, after receiving optimal regional therapy, to receive either doxorubicin hydrochloride (450 mg/m2) (37 patients) or observation (38 patients). Follow-up has ranged from 16 to 80 months (median, 49 months). Twenty-five patients (33%) died, and two patients receiving doxorubicin developed cardiotoxicity. No significant differences in local control, metastasis-free survival, disease-free survival, and overall survival were observed for the two treatment arms. Despite temporary prolongation of disease-free survival with doxorubicin in some subgroups, we conclude that there is no advantage to the use of adjuvant doxorubicin in the treatment of soft-tissue sarcoma.

Elimination of clonogenic tumor cells from human bone marrow using a combination of monoclonal antibody:ricin A chain conjugates

Effective autologous bone marrow transplantation for leukemia and lymphoma is likely to depend upon the selective removal in vitro of malignant cells from normal human bone marrow precursors. Highly specific cytotoxic conjugates formed by coupling ricin A chain to monoclonal antibodies might prove useful for the selective elimination of malignant cells. Consequently, ricin A chain conjugates have been prepared with several different murine monoclonal antibodies and tested for their ability to eliminate clonogenic Burkitt's lymphoma cells from an excess of human bone marrow. The most active reagents included an antibody:A chain conjugate which bound to the nonpolymorphic chain of the la molecule and another which reacted with the mu heavy chain of cell surface immunoglobulin. Conjugates formed with anti-common acute lymphoblastic leukemia antigen, anti-Mr 26,000 glycoprotein, and anti-B1 were much less active on these Burkitt's cells, contrasting with results of complement-dependent tumor cell lysis. Tumor cell kill was partially inhibited by the addition of greater than 2 X 10(6) human bone marrow cells/ml but could be potentiated by increasing the concentration of conjugate or by the addition of 10 mM ammonium chloride. In the presence of ammonium chloride, at least 4 logs of clonogenic tumor cells could be eliminated within 24 h from a 20-fold excess of bone marrow using 10(-7) M ricin A chain linked to one or two different antibodies. Similar treatment of normal human bone marrow temporarily inhibited granulocyte-macrophage colony-forming units (cell) formation but did not compromise establishment of continuous bone marrow cultures. The degree of selective elimination of tumor cells with A chain antibody conjugates was comparable to that achieved with 4-hydroperoxycyclophosphamide or with multiple monoclonal antibodies and complement.

Selection bias in clinical trials

Of 90 patients with intermediate or high-grade sarcoma eligible for a randomized trial of adjuvant doxorubicin (Adriamycin, Adria Laboratories, Columbus, Ohio), 48 were not entered: 24 (27%) by physician's choice and 24 refused randomization. Sixty-five percent of lower stage patients were randomized compared with 37% of those with higher stage (P = .02). Patients with extremity lesions were more frequently offered participation in the study (P = .07). Patients with lower stage lesions accepted randomization more readily than those with higher stage lesions (P = .01). As predicted by the higher stage and percentage of central lesions, the disease-free survival of nonrandomized patients was inferior to that of randomized patients (P = .15). Thus, patients at high risk appeared to avoid randomization and adjuvant doxorubicin in this trial, resulting in an inferior disease-free survival for the nonrandomized control group. Important questions generally require randomized trials that reliably determine relative treatment differences. If, however, the patients in a clinical trial are not representative of the entire patient population because of patient and physician selection biases, the generalizability of the results to the entire patient population may be compromised. For example, the prognosis of the general population cannot necessarily be inferred from the selected group in the study. In this study, the randomized and nonrandomized series yielded differing conclusions regarding treatment efficacy, even when an adjustment was made for known prognostic facts.

Elimination of clonogenic Burkitt's lymphoma cells from human bone marrow using 4-hydroperoxycyclophosphamide in combination with monoclonal antibodies and complement

One requirement for autologous bone marrow transplantation is the selective removal of malignant cells from normal marrow precursors. Development of a clonogenic assay that detects elimination of up to 5 logs of Burkitt's lymphoma cells in the presence of a 20-fold excess of human bone marrow has permitted the evaluation of two different methods for the selective removal of malignant cells. Treatment with 4-hydroperoxycyclophosphamide (4-HC) (60 to 100 micrograms/mL) eliminated 2.0 to 3.5 logs of clonogenic cells. Antitumor activity depended upon the concentration of 4-HC and the length of incubation, but not upon the concentration of normal bone marrow cells. Comparable removal of clonogenic Burkitt's cells was achieved by treatment with rabbit complement (C') and a combination of J5 anti-common acute lymphoblastic leukemia antigen (J5 anti-CALLA), J2 anti-gp 26, and the B1 anti-B1 murine monoclonal antibodies. A combination of 4-HC and monoclonal antibodies proved slightly but significantly more effective than either single agent in eliminating clonogenic tumor cells. Although treatment with 4-HC markedly reduced granulocyte-macrophage colony-forming units-C (GM-CFU-C) content of human bone marrow, neither treatment with 4-HC nor treatment with monoclonal antibodies and C' eliminated precursor cells that could generate new GM-CFU-C after growth in continuous bone marrow cultures. Our data suggest that treatment with 4-HC in combination with multiple monoclonal antibody reagents could be a safe and effective method of eliminating clonogenic tumor cells from human bone marrow.

Preliminary results of a randomized trial of adjuvant doxorubicin for sarcomas: lack of apparent difference between treatment groups

Forty-two patients with localized intermediate and high-grade sarcoma were randomized after optimal primary treatment to receive five cycles of adjuvant doxorubicin 90 mg/m2 every three weeks (20 patients) or observation (22 patients). Patients were stratified for grade, size, extent of surgical margin, and soft tissue versus other sarcomas. Groups appeared balanced for histology and superficial versus deep lesions. Eight patients (19%) have died. Follow-up times range from two to 69 months (median, 16 months). Two patients receiving doxorubicin (10%) developed cardiotoxicity presenting as pulmonary edema. One patient returned to normal activity on digoxin and diuretics; the other (age, 28 years) died of intractable failure and arrhythmias after four weeks. While a nonsignificant difference in local control, metastasis-free survival, disease-free survival, and survival was observed for extremity lesions, the advantage may be outweighed by the risk of cardiotoxicity. Seventy-six percent of the control patients with extremity lesions remain disease free. Because control patients do well, a very large study is required to define the role of adjuvant doxorubicin.

Malignant mesothelioma following radiation exposure

Mesothelioma developed in proximity to the field of therapeutic radiation administered 10-31 years previously in four patients. In three, mesothelioma arose within the site of prior therapeutic radiation for another cancer. Mesothelioma in the fourth patient developed adjacent to the site of cosmetic radiation to a thyroidectomy scar. None of these four patients recalled an asbestos exposure or had evidence of asbestosis on chest roentgenogram. Lung tissue in one patient was negative for ferruginous bodies, a finding considered to indicate no significant asbestos exposure. Five other patients with radiation-associated mesothelioma have been reported previously, suggesting that radiation is an uncommon cause of human mesothelioma. Problems in the diagnosis of radiation-associated mesotheliomas are considered.

Multimodality therapy in the management of angiosarcoma of the breast

Five patients with angiosarcoma of the breast were treated with surgery, radiotherapy and an adjuvant Adriamycin containing regimen. Two patients remain disease-free at 38+ and 20+ months. The median survival of previously reported cases is 22 months with only five patients disease-free at five years. Possible hormonal influences in the etiologic cause of angiosarcoma of the breast are discussed and the importance of early diagnosis and treatment in these relatively young patients is emphasized.

Twice-a-day fractionation preoperative radiotherapy in patients with carcinoma of the bladder: preliminary report

There were 13 patients with carcinoma of the bladder who received preoperative radiotherapy by a modified regimen before cystectomy. Doses of 135 rad were delivered twice daily for 10 days (2,700 rad) to a 15 times 15 cm. portal and followed by immediate cystectomy. Patient tolerance has been excellent, morbidity has been minimal and no increase in operative time, blood loss of major intraoperative or postoperative complications has ensued. The theoretical and practical advantages of this regimen may outweight either the standard regimen of 4,500 rad with a 4-week hiatus before operation or the high dose, short course regimen of 2,000 rad in 5 days and immediate cystectomy.