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Biomedical subjects

D W Kufe

Publications and source records attributed to D W Kufe.

At least 163 records · Page 9Linked to original sources
PubMed1986

Inhibitory effects of theophylline and dibutyryl cAMP on murine erythroleukemia cell differentiation.

Murine erythroleukemia cells can be induced to differentiate by a variety of compounds. We have previously shown that 5'-methylthioadenosine, an inhibitor of cAMP phosphodiesterase, blocks induction of these cells. The present study demonstrates that theophylline, another cAMP phosphodiesterase inhibitor, also blocks murine erythroleukemia cell differentiation in a concentration-dependent manner. Northern blot analysis indicates that this agent inhibits accumulation of alpha- and beta-globin transcripts. These findings are extended by demonstrating that dibutyryl cAMP exerts similar effects. Furthermore, theophylline and dibutyryl cAMP are synergistic in inhibiting appearance of the mature erythroid phenotype. The results thus suggest that cAMP regulates induction of murine erythroleukemia cell differentiation.

Animals↗
PubMed1986

Low dose ara-C administered by continuous subcutaneous infusion: a pharmacologic evaluation.

Low dose ara-C has been widely used in the treatment of preleukemia and leukemia. These studies have generally utilized either a twice daily, subcutaneous bolus schedule or a continuous intravenous infusion schedule. In order to surmount the logistical problems of long term intravenous infusion while providing prolonged ara-C exposure, we have studied the pharmacology of administering ara-C (20 mg/M2/d) by continuous subcutaneous infusion. The results obtained in eight patients demonstrate that steady state plasma ara-C levels achieved during continuous subcutaneous infusion (24.6-65.6 nM) are not significantly different than those obtained during intravenous infusions (26.2-61.5 nM). Subcutaneous infusions result in prolonged myelosuppression similar to that seen with continuous intravenous infusions. The continuous infusion of low dose ara-C by the subcutaneous route provides a treatment option for some outpatients and offers advantages over intravenous infusions which often require placement of venous catheters or hospitalization.

Adult↗
PubMed1986

Comparison of circulating CA15-3 and carcinoembryonic antigen levels in patients with breast cancer.

An immunoradiometric assay (IRMA) has been used to determine circulating levels of the breast cancer-associated antigen, CA15-3. Of 1,050 normal control subjects, serum from 99 (9.4%) had CA15-3 antigen levels greater than 22 U/mL, while that from 58 (5.5%) and 14 (1.3%) had levels greater than 25 U/mL and 30 U/mL, respectively. In contrast, 115 of 158 patients (73%) with metastatic breast cancer had CA15-3 levels greater than 22 U/mL. Thirteen of 26 patients (50%) with only local metastases, 27 of 34 (79%) of those with only bone metastases, and 20 of 24 (83%) with hepatic metastases had CA15-3 levels greater than 22 U/mL. Furthermore, nine of 31 patients (29%) with primary breast cancer had CA15-3 levels greater than 22 U/mL. CA15-3 and carcinoembryonic antigen (CEA) levels were compared for the same patient population. Significantly more patients with metastatic breast cancer had elevated CA15-3 levels than had elevated CEA levels (P less than .001). Furthermore, the CA15-3 IRMA was more sensitive than the CEA assay in patients with only bone metastases, as well as those with only local metastases. Significantly more patients with primary carcinoma of the breast also had elevated CA15-3 than had elevated CEA levels (P less than .02). CA15-3 levels were greater than 22 U/mL in patients with nonmalignant conditions, including five of 25 patients (20%) with benign breast diseases, and 23 of 52 patients (44%) with benign liver diseases. Furthermore, CA15-3 levels were also greater than 22 U/mL in 24 of 54 patients (44%) with gastrointestinal (GI) malignancies, 12 of 17 patients (71%) with bronchogenic carcinoma, and 29 of 44 patients (66%) with epithelial ovarian carcinoma. Serial CA15-3 levels correlated with clinical disease course. Nineteen of 21 patients (91%) with tumor progression had at least a 25% increase in CA15-3 levels. Conversely, seven of nine patients (78%) with tumor regression had at least a 50% decrease in CA15-3 levels. Among 27 patients with stable disease, 16 (59%) had levels that did not vary by more than +/- 25% of the original CA15-3 levels. These results indicate that the CA15-3 antigen is a sensitive marker for the evaluation and monitoring of patients with breast cancer.

Antibodies, Monoclonal↗
PubMed1986

Fludarabine phosphate (NSC 312878) infusions for the treatment of acute leukemia: phase I and neuropathological study.

Fludarabine phosphate (NSC 312878), an adenosine deaminase resistant analogue of 9-beta-D-arabinofuranosyladenine, has entered clinical trials. Eleven patients with acute leukemia in relapse received 14 courses of fludarabine phosphate as a 5-day continuous infusion administered at doses of 40 to 100 mg/m2/day. Toxicity was characterized by uniform myelosuppression, as well as occasional nausea, vomiting, and hepatotoxicity. Three episodes of metabolic acidosis and lactic acidemia were noted. In addition, three patients suffered neurotoxicity. Two of these three patients had a severe neurotoxicity syndrome characterized by blindness, encephalopathy, and coma. Neither patient recovered neurological function. Neuropathological findings at autopsy were characterized by a diffuse, necrotizing leukoencephalopathy which was most severe in the occipital lobes. The medullary pyramids and posterior columns were also severely affected. This sporadic fatal neurotoxicity was observed only at doses greater than 40 mg/m2/day. The maximum tolerated dose for a 5-day infusion of fludarabine phosphate is thus 40 mg/m2/day.

Acidosis↗
PubMed1986

Reactivity of monoclonal antibody DF3 with a high molecular weight antigen expressed in human ovarian carcinomas.

We have previously described the monoclonal antibody (MAb) DF3, prepared against a human breast carcinoma. MAb DF3 reacts with a high molecular weight glycoprotein detectable in human breast carcinomas and in human milk. Previous studies have demonstrated that DF3 antigen levels are elevated in the plasma of patients with breast and ovarian cancer. The present study has further examined the reactivity of MAb DF3 with human ovarian carcinomas. Immunoperoxidase staining demonstrated reactivity of MAb DF3 with 95% of benign, borderline, and malignant tumors (serous, mucinous, and endometrioid) of the ovary. Furthermore, malignant tumors contained cytoplasmic DF3 antigen while benign tumors expressed the antigen only on apical surfaces. Western blot analyses demonstrated that the MAb DF3 reactive ovarian antigen (DF3-O) was a glycoprotein with a heterogenous molecular weight ranging between 300,000 and 450,000. This antigen was detectable by immunofluorescence on the cell surface of five of six cultured human ovarian carcinoma cell lines. The extent of cell surface reactivity with MAb DF3 was equivalent to or greater than that obtained with MAb OC125, an antibody generated against coelomic epithelium and developmental amnion. Furthermore, uptake of 125I-labeled MAb DF3 by human ovarian carcinoma xenografts in athymic mice was 5.4- and 6.2-fold higher than the respective uptake noted in liver and control tumor (P = 0.031). These findings suggest that DF3-O antigen is similar if not identical to the antigen detected in human breast carcinomas by MAb DF3. Thus, MAb DF3 may be a useful reagent in immunodiagnostic evaluation of patients with ovarian cancer.

Adenocarcinoma↗
PubMed1986

The treatment of myelodysplastic syndromes.

The available data fail to support a standard therapy for MDS. Any therapy should therefore, include participation in a well designed clinical trial. The MDS include patients with a variety of prognoses. Since most studies show that death from infection and bleeding are more likely than progression to frank leukaemia, attention to supportive care is crucial for all patients with MDS. Some patients with MDS may be successfully supported with transfusions and observation for prolonged periods. Patients with significant comorbid disease or patients without increased marrow myeloblasts are good candidates for this conservative approach. Conversely, young patients have a better likelihood of benefit from aggressive therapy, and intensive chemotherapy or allogenic bone marrow transplantation should be considered. Patients with preleukaemia related to prior cytotoxic therapy are another poor prognosis group for whom aggressive therapy may be the best alternative. Therapy with low-dose ara-C or other differentiating agents should be considered investigational and unproven until comparative trials can demonstrate a definitive survival advantage. In addition to comparative trials, innovative clinical studies are needed to address differentiation as an in vivo mechanism of action and its importance in MDS therapy.

Adult↗
PubMed1986

Pharmacokinetics of radiolabeled monoclonal antibody B6.2 in patients with metastatic breast cancer.

Thirteen patients with metastatic breast carcinoma were given injections of 50-1593 micrograms of 131I-monoclonal antibody (MAb) B6.2 immunoglobulin G and F(ab')2 for pharmacokinetic evaluation and radioimmunoimaging. Blood clearance of the 131I-MAb-B6.2 was biphasic. The mean half-times (t 1/2 alpha, t 1/2 beta) for the immunoglobulin G were 3.5 +/- 1.7 and 20.9 +/- 11.0 h, respectively. The t 1/2 alpha for the F(ab')2 was 1.7 +/- 1.3 h, and the t 1/2 beta was 31.0 +/- 5.7 h. The percentage of protein bound 131I for the immunoglobulin G and for the F(ab')2 at 72 h was 73.7 +/- 11.4% and 58.2 +/- 14.5%, respectively. In vitro reactivity of MAb B6.2 with granulocytes isolated from normal subjects and patients was demonstrated by cytofluorometric and radioimmunoassays. MAb B6.2 was shown to bind with normal cross-reacting antigen, a cell surface antigen known to be expressed on normal human granulocytes. Reactivity with normal cross-reacting antigen on granulocytes is consistent with the skeletal images obtained during immunoscintigraphy of all 13 patients. A specific tumor image was observed in one patient. No toxicity was encountered. In spite of extensive preclinical data suggesting that 131I-MAb B6.2 would be a useful agent for radioimmunoimaging, the clinical utility of this reagent is probably limited because of the reactivity with granulocytes.

Adult↗
PubMed1985

Requirement of spermidine for induction of both heme synthesis and globin transcription in murine erythroleukemia cells.

We have previously demonstrated that spermidine is required for proliferation and differentiation of murine Friend erythroleukemia (MEL) cells. Other studies have indicated that inhibition of MEL differentiation by dexamethasone (DEX) and 12-0-tetradecanoylphorbol-13-acetate (TPA) is reversed by the addition of exogenous polyamines. The present work has thus monitored the requirements of polyamines for induction of MEL hemoglobin synthesis by dimethyl sulfoxide. The results demonstrate that spermidine depletion inhibits induction of both heme synthesis and transcription of alpha- and beta-globin mRNA. In contrast, the results also demonstrate that polyamines are not involved in the inhibition of MEL differentiation by DEX and TPA. Thus, spermidine is required at a transcription level for induction of MEL hemoglobin synthesis, but DEX and TPA act by mechanisms other than polyamine depletion.

Animals↗
PubMed1985

Radioiodinated B6.2 monoclonal antibody: further characterization of a potential radiopharmaceutical for the identification of breast tumors.

A monoclonal antibody (B6.2) directed against human breast carcinomas and its F(ab')2 and Fab' fragments were labeled with 125I using Iodogen. Solid phase radioimmunoassay was used to evaluate the in vitro binding of the labeled antibodies to a human breast tumor metastasis to the liver, the MCF-7 breast tumor cell line and normal liver tissue. Scatchard analysis revealed that 125I-labeled B6.2 IgG and F(ab')2 bound to both breast tumors with affinity constants in the range 1.2-4.4 X 10(9) M-1, while the affinity constant for the binding of the 125I-labeled Fab' fragment to the metastasis and the MCF-7 line was 5.9 and 9.1 X 10(8) M-1, respectively. Serial blood sampling indicated that blood clearance of 125I activity decreased with increasing protein size. A comparison of tumor-to-tissue ratios at two doses of 125I-B6.2 IgG and F(ab')2 suggests that the optimal dose of antibody may depend on the imaging time. A comparison of the blood clearance of 125I activity following injection of 125I-B6.2 and nonspecific 125I-MOPC 21 demonstrated that the specific antibody cleared much more rapidly. When 125I-B6.2 was injected into mice bearing either breast or melanoma tumors, the thyroid uptake of 125I was significantly greater in mice with breast tumors. These results suggest that the catabolism of radiolabel from the specific antibody in the presence of tumor is greater and that this may be an important factor in determining the optimal radiolabel for immunoscintigraphy.

Animals↗
PubMed1985

Use of a murine monoclonal antibody for detection of circulating plasma DF3 antigen levels in breast cancer patients.

The murine monoclonal antibody (MAb), designated DF3, reacts with a 300,000-mol wt mammary epithelial antigen. A sequential double-determinant radioimmunoassay (RIA) has been developed to monitor circulating DF3 antigen. Using this assay, we have demonstrated that 33 of 36 normal women had plasma RIA antigen levels less than 150 U/ml. In contrast, 33 of 43 patients (76%) with metastatic breast cancer had RIA DF3 antigen levels greater than or equal to 150 U/ml. The difference between these two groups was statistically significant (P less than 0.001). Similar results have been obtained with a double-determinant enzyme-linked immunoassay (EIA). Only 6 of 111 age-matched normal subjects had EIA DF3 antigens levels greater than or equal to 30 U/ml, while 42 of 58 patients (72%) with breast cancer had levels equal to or above this value. Thus, similar patterns of specificity are obtained with the EIA or RIA. The elevation of circulating DF3 antigen levels in breast cancer patients has been confirmed by transfer blot assays. MAb DF3 reactivity occurred predominantly with circulating antigens of three different molecular weights ranging from 300,000 to approximately 400,000 mol wt. We also demonstrate that patients with both primary and metastatic breast cancer who were free of detectable disease at the time of sampling have DF3 antigen levels that are similar to those obtained from normal subjects. While patients with hepatoma (27%) and ovarian carcinoma (47%) also had elevated circulating DF3 antigen levels, the results suggest that DF3 antigen levels may be useful in distinguishing breast cancer patients from those with esophageal, gastric, colorectal, pancreatic, and lung carcinomas. Furthermore, the results of the RIA, EIA, and transblot analyses demonstrate that the measurement of circulating DF3 antigen levels provides a new and potentially useful marker to follow the clinical course of patients with metastatic breast cancer.

Adult↗
PubMed1985

Circulating DF3 and CA125 antigen levels in serum from patients with epithelial ovarian carcinoma.

The murine monoclonal antibody (MAb), designated DF3, reacts with a 300-kilodalton (kd) mammary epithelial antigen. A sequential double-determinant enzyme-linked immunoassay (EIA) has been developed to monitor circulating DF3 antigen. Previous studies have demonstrated that the use of the DF3 EIA provides a new and potentially useful marker to follow the clinical course of patients with metastatic breast cancer. In the present study, we have monitored circulating DF3 antigen in the serum of patients with epithelial ovarian carcinomas and non-ovarian gynecologic malignancies. Twenty-one of 45 patients (47%) with ovarian carcinoma had elevated DF3 antigen levels (greater than or equal to 30 U/mL). In contrast, three of 20 patients (15%) with non-ovarian gynecologic malignancies, and only four of 59 control women (7%) had elevation of circulating DF3 antigen. The difference between DF3 antigen values from patients with ovarian cancer and from controls was significant (P less than .001). The elevation of circulating DF3 antigen in ovarian cancer patients has also been confirmed by transblot assays. MAb DF3 reactivity occurred predominately with circulating antigens of molecular weights (mol wt) ranging from 300 to 450 kd. Furthermore, DF3 antigen levels have been shown to correlate with progression of disease in six patients with ovarian cancer and after resection of disease in two others. The half-life of circulating DF3 antigen was approximately 45 to 60 days. The results also demonstrate that DF3 antigen is distinct from CA125, a glycoprotein associated with coelomic epithelium and developmental amnion. The use of both the DF3 EIA and the immunoradiometric assay previously described to detect circulating CA125 suggests that determining levels of both markers may enhance the sensitivity of monitoring the course of ovarian cancer. Furthermore, the use of both assays may be useful in distinguishing ovarian cancer from other malignancies.

Adult↗
PubMed1985

Treatment of preleukemic syndromes with continuous intravenous infusion of low-dose cytosine arabinoside.

Preleukemic syndromes compose a group of acquired bone marrow disorders characterized by dysplastic maturation of hematopoietic cells and peripheral blood cytopenias. These syndromes have been generally considered untreatable. We administered low doses of cytosine arabinoside by continuous infusion for 14 to 21 days (20 mg/m2/d) to 16 patients with preleukemia in various stages of evolution to acute leukemia. Steady state plasma cytosine arabinoside levels ranged from 41.8 to 64.2 nmol/L. Eleven patients demonstrated marked improvement in hematopoiesis and loss of transfusion requirements for periods ranging from two to 27 + months. All but one responding patient developed recurrent pancytopenia, but additional responses to low-dose cytosine arabinoside were achieved in five of five retreated patients. Median overall survival time is 12 months for the 11 responding cases, and nine months for nonresponders. The major toxicity of low-dose cytosine arabinoside is myelosuppression, and most patients required platelet transfusion support and administration of antibiotics. Chromosome analyses demonstrated evolution to a new clone of hematopoietic cells in three patients, and persistence of the same abnormal clone in another patient. These results suggest that low-dose cytosine arabinoside therapy may result in improved hematopoiesis by promoting maturation or by selecting new stem cell clones. Low-dose cytosine arabinoside therapy thus deserves further evaluation both as a single agent and in combination with other agents in the treatment of myelodysplastic syndromes.

Adult↗
PubMed1985

Inhibition of murine erythroleukemia cell differentiation by 3-deazaadenosine.

Recent studies have demonstrated that 5'-methylthioadenosine, an inhibitor of S-adenosylhomocysteine (AdoHcy) hydrolase, blocks induction of murine erythroleukemia cell (MEL) differentiation. The nucleoside analogue 3-deazaadenosine (c3Ado) is both an efficient substrate and a potent inhibitor of AdoHcy hydrolase. The present study was undertaken to determine whether c3Ado would similarly inhibit MEL differentiation. The results demonstrate that c3Ado inhibits induction of MEL differentiation by dimethyl sulfoxide, hexamethylene bisacetamide, butyric acid, and diazapam. c3Ado blocks the appearance of the differentiated MEL phenotype by inhibiting both MEL heme synthesis and transcription of alpha- and beta-globin RNA. The inhibitory effect of c3Ado on MEL differentiation is concentration dependent, reversible, and potentiated by L-homocysteine thiolactone. Furthermore the AdoHcy/AdoMet ratio increases nearly 3.5-fold after 24 h of treatment with 50 microM c3Ado. In contrast, this c3Ado effect is not associated with polyamine depletion or cytostasis. These findings indicate that c3Ado blocks the induction of MEL differentiation at a transcriptional level and that this effect may be related to inhibition of AdoHcy hydrolase.

Adenosine↗
PubMed1985

Cellular and clinical pharmacology of low-dose ara-C.

Although the mechanism of action responsible for the effects of low-dose ara-C remains unclear, certain insights are available concerning the interaction of this agent with DNA. Ara-C incorporates into DNA, and the extent of (ara-C)DNA formation correlates significantly with loss of clonogenic survival. The inhibition of DNA replication by ara-C also results in DNA fragmentation and terminal differentiation of leukemic cells. Other studies have demonstrated that inhibition of DNA replication by ara-C results in an aberrant form of DNA synthesis with certain segments of DNA being replicated more than once within a single cell cycle. The additional copies of certain segments of DNA could lead to the accumulation of DNA fragments and alterations in gene expression. It is of interest that other inhibitors of S-phase DNA replication such as aphidicolin and hydroxyurea can also induce similar phenotypic changes in HL-60 and K562 leukemia cells. Although the in vitro data support the concept that ara-C is capable of inducing leukemic cell differentiation, there is no evidence to suggest that this agent induces differentiation of human leukemic cells in vivo. Drug levels achieved by administration of low-dose ara-C (42-64 nmol/L) result in the incorporation of ara-C into bone marrow mononuclear preparations from patients with preleukemia syndromes. This concentration of ara-C (5 X 10(-8) mol/L) slows DNA replication of human leukemic cells in vitro. Thus, the clinical use of low doses of ara-C that achieve plasma concentrations of 10(-8) to 10(-7) mol/L could theoretically induce maturational effects by partially inhibiting DNA synthesis. At the present time we have no available data to support this contention. On the basis of chromosomal analyses, low-dose ara-C apparently maintains sufficient drug levels to suppress more "malignant" clones, but even "clonal" selection may represent elimination of leukemic cells by either cytotoxicity or induction of terminal differentiation. Further studies will be necessary to define the mechanism of action of low-dose ara-C in preleukemia.

Adult↗
PubMed1985

TPA induces differentiation of purified human myeloblasts in the absence of proliferation.

Normal granulocyte-monocyte progenitor cells have an absolute requirement for colony-stimulating factor (CSF) for proliferation and differentiation in vitro. In contrast, cells derived from acute myeloblastic leukemia patients are often defective in their response to CSF, but can be induced to undergo terminal differentiation by exposure to 12-o-tetradecanoyl phorbol-13-acetate (TPA) by a process that does not require cell proliferation. To investigate the relationship between TPA-induced leukemic cell differentiation and CSF-induced myeloid cell differentiation we investigated the effects of TPA on myeloblasts highly enriched from normal bone marrow and stable-phase chronic myeloid leukemia peripheral blood. TPA (10(-6)-10(-9) M) induced the rapid appearance of macrophage characteristics in the majority of myeloblasts in the absence of proliferation. The mechanisms of TPA- and CSF-induced myeloblast differentiation were compared by examining the requirement for DNA synthesis. Exposure of myeloblasts to CSF induced increased triatiated thymidine (3H-TdR) incorporation within a few hours, while TPA did not induce 3H-TdR incorporation by itself and was inhibitory to CSF-induced 3H-TdR uptake. This requirement for DNA synthesis was further investigated by reversibly inhibiting DNA synthesis by depleting intracellular polyamines with difluoromethylorinithine (DFMO). DFMO inhibited both CSF-induced proliferation and differentiation of myeloblasts, but had no effect on TPA-induced differentiation. These results demonstrate that the process of differentiation of myeloblasts induced by TPA is distinct from CSF-induced differentiation.

Bone Marrow↗