Lateral diffusion in nuclear membranes.

Chemical modification of rat liver nuclei with citraconic anhydride selectively removed outer nuclear membrane. This conclusion was based on (a) transmission electron microscopy, (b) lipid analysis, (c) lamin B as an inner membrane-associated marker, and (d) the demonstration of phospholipid lateral mobility on outer membrane-depleted nuclei as a criteria for inner membrane integrity. Addition of urea or N-ethylmaleimide resulted in the additional disruption of inner membrane. Fluorescence photobleaching was used to determine the long range (greater than 4 microns) lateral transport of lectin receptors and a phospholipid analog in both membranes. The diffusion coefficient for wheat germ agglutinin on whole nuclei was 3.9 X 10(-10) cm2/s whereas the diffusion coefficient for wheat germ agglutinin in outer membrane-depleted nuclei was less than or equal to 10(-12) cm2/s. Phospholipid mobilities were the same in whole and outer membrane-depleted nuclei (3.8 X 10(-9) cm2/s). The protein diffusion differences observed between whole and outer membrane-depleted nuclei may be interpreted in the context of two functionally different membrane systems that compose the double bilayer of the nucleus.

Lipids trigger changes in the elasticity of the cytoskeleton in plant cells: a cell optical displacement assay for live cell measurements.

An assay has been developed to quantitatively measure the tension and elasticity of the cytoskeleton in living plant cells. The cell optical displacement assay (CODA) uses a focused laser beam to optically trap and displace transvacuolar and cortical strands through a defined distance within the cell. Results from these experiments provide evidence for the classification of at least two rheologically distinct cytoskeletal assemblies, cortical and transvacuolar, that differ in their tension and response to both signaling molecules and reagents that perturb the cytoskeleton. It is further demonstrated that the tension of the transvacuolar strands can be significantly decreased by the addition of either linoleic acid, 1,2 dioctanoyl-sn-glycerol, or 1,3 dioctanoylglycerol. These decreases in tension could also be induced by lowering the cytoplasmic pH. In contrast, addition of Ca2+, Mg2+, or the ionophore A23187 to the cells caused a considerable increase in the tension of the transvacuolar strands. The data provides evidence that: (a) linoleic acid may be a signaling molecule in plant cells; (b) diacylglycerol functions as a signaling molecule through a protein kinase C-independent pathway mediated by PLA2; and (c) Ca2+ and pH have regulatory roles for controlling cytoskeleton tension and organization.

Lymphocyte function of Michigan dairy farmers exposed to polybrominated biphenyls.

Michigan dairy farm residents ate farm products containing polybrominated biphenyls (PBB's) after the accidential contamination of animal feed with the chemical in that state in 1973. The circulating blood lymphocytes of these residents show significant changes. Abnormalities include decreases in the numbers and percentages of peripheral blood lymphocytes that form rosettes with either sheep erythrocytes alone or with sheep erythrocytes sensitized with antibody and complement, increases in lymphocytes with no detectable surface markers ("null" cells), and altered responses to tests designed to evaluate functional integrity of the cells. There appears to be no consistent correlation between the concentration of PBB's in the plasma and the altered lymphocytes. Studies showed that in Wisconsin dairy farm residents and healthy individuals in the New York area who were not exposed to PBB's there were no such abnormalities.

L-asparagine requirements of human T-lymphocytes and B-lymphocytes in culture.

The characterization of two human T-lymphocyte lines revealed that they required exogenous L-asparagine for cell growth, whereas all four B-cell lines studied were L-asparagine independent. T-cells were 800-2,000 times more sensitive to Escherichia coli L-asparaginase than were B-cells. The cytotoxic effects of a high concentration of L-asparaginase on B-cells were not related to the hydrolysis of L-asparagine but were due to heat-labile and heat-resistant substances in the enzyme. The findings were consistent with reports that L-asparaginase is effective in suppressing cellular immunity and inducing remission in patients with acute lymphocytic leukemia, mainly a non-B-cell disease. Thus these cell lines provide in vitro models for the study of a nutritional approach to chemotherapy or immunotherapy.

Differential chemotherapeutic susceptibility of human T-lymphocytes and B-lymphocytes in culture.

After previous work from this laboratory revealed that asparaginase was 800-2,000 times more inhibitory against human T-lymphocytes in culture than against B-lymphocytes, a similar further study of 13 chemotherapeutic and immunosuppressive agents was done. Cytosine arabinoside and 5-fluorouracil also had differential inhibitory activities on human T- and B-cells in culture. On the basis of the dose producing 50% inhibition of viable cell growth on day 5, cytosine arabinoside had 45-80 times more inhibitory activity against T-cells than against B-cells. In contrast to asparaginase and cytosine arabinoside, 5-fluorouracil had 10-20 times more inhibitory activity against B-cells. The rest of the chemotherapeutic and immunosupressive agents tested had minor or no differential activity. These findings indicated that T-cell response to asparaginase and cytosine arabinoside and B-cell response to 5-fluorouracil may be exploitable for the differential immunosuppressive effects presumed to be active in vivo. In addition, such differential responses may predict differential tumor cell behavior against these chemotherapeutic agents by T- and B-cell neoplasms in vivo.

Early diagnosis and monitoring of transplanted human malignant mesothelioma by serum hyaluronic acid.

Serum concentrations of unhydrolyzed hyaluronic acid (HA) in nude mice bearing human malignant mesothelioma xenografts were determined by size-exclusion chromatography. HA rose to 8-16 micrograms/mL (controls: less than 1 micrograms/mL) by the fourth to fifth day after tumor (epithelial) transplantation, 3 to 5 days before palpability. Decreases in HA during late tumor growth are probably attributed to tumor necrosis, based on the observation that HA was 2.5 times less in necrotic than in viable tumor tissues. This serum biomarker, recognizable before physical detectability of xenografted tumors, should have applicability to monitoring experimental chemotherapy in mice and to early diagnosis and monitoring of human malignant mesothelioma.

Combined cytotoxicity effect of hyperthermia and anthracycline antibiotics on human tumor cells.

The effects of temperature on the anthracycline antibiotics-induced cell kill of DND-1A human malignant melanoma (MM) and DND-39A Burkitt's lymphoma (BL) cell lines were studied by means of a clonogenic assay. The two cell lines differed in sensitivity when exposed to heat: The MM cells were unaffected by hyperthermia (42 degrees C), whereas BL cells were sensitive to this temperature. With the MM cells, hyperthermia potentiated the cytotoxic effects of doxorubicin (ADM), daunorubicin, mitoxantrone (DHAD), and quelamycin but did not enhance that of aclacinomycin (ACM). Conversely, the exposure of cells to the anthracycline compounds at 0 degree C resulted in almost complete disappearance of cell kill effects except with ACM; ACM retained substantial cell kill effects even at the given low temperature. For BL cells, ADM- or DHAD-induced cell lethality was also potentiated by hyperthermia; ACM produced only additive cell kill. At 0 degree C, ACM's effects virtually disappeared. These data indicate that human tumor cell lines have a substantial variety in heat sensitivity and that not every anthracycline antitumor agent is potentiated by temperature. ACM's thermoresponse is unique among anthracycline antibiotics studied. Additionally, it was shown that normothermic cell kill by ADM was not affected by hyperthermic preheating; however, preheating of appropriate duration produced important influence on subsequent hyperthermic ADM-induced cell kill.

Interference of mouse mammary tumor virus replication by PTT.119 [p-fluoro-L-phe-m-bis-(2-chloroethyl)amino-L-phe-met ethoxy HCl]--an antitumor agent.

PTT.119 [p-fluoro-L-Phe-m-bis-(2-chloroethyl)-amino-L-Phe-Met ethoxy HCl] is a new bifunctional alkylating compound that possesses both cytolytic and antiviral activities. Continuous treatment of mouse mammary tumor cells with 15 microM PTT.119 reduced production of the B-type retrovirus murine mammary tumor virus (MuMTV). MuMTV levels in PTT.119-treated cultures were reduced by 31% in the first 24 hours; an additional 24 hours of treatment resulted in a further reduction of 70%. These reductions were significantly greater than could be accounted for by the effects of PTT.119 tumor cell metabolism and viability. Under identical treatment conditions, equimolar concentrations of L-phenylalanine mustard reduced MuMTV production by only 3%. PTT.119 inhibition of MuMTV replication was also apparent when mammary tumor cells were exposed for periods as short as 0.5-4 hours; persistent decreases in virus production were detected even 7 days following tripeptide treatment. Analyses of the polypeptide composition of MuMTV by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that virions from these PTT.119-treated mammary tumor cultures contained significant reductions in the relative level of the nonglycosylated 24,000-dalton (p24) viral polypeptide associated with the nucleoprotein core. Decreases in p24 were observed in MuMTV produced in the presence of the tripeptide and 1-7 days after removal of PTT.119. Examination of the steady-state levels and rates of intracellular MuMTV protein synthesis suggested that PTT.119 interferes with late steps in MuMTV processing and maturation.

Inhibition of invasion of invasive human bladder carcinoma cells by protein kinase C inhibitor staurosporine.

To study the effect of the protein kinase C (PKC) inhibitor staurosporine on invasion, we selected the invasive human bladder carcinoma cell line EJ. Total PKC activity was more than twofold higher in the EJ cells than in RT4 cells (superficial human bladder carcinoma cells), which do not pass through an artificial basement membrane. There was more PKC activity in the cytosol than in the membrane of EJ cells. Staurosporine, at nontoxic concentrations, inhibited the invasion of EJ cells through an artificial basement membrane in a dose-dependent manner. Staurosporine caused a dose-dependent inhibition of cell motility but did not inhibit cell attachment. Staurosporine represents a new agent for the inhibition of tumor cell invasion and may prove useful in studying the mechanisms responsible for this phenomenon.

Intensive single-agent mitoxantrone for metastatic breast cancer.

Twenty-seven women with metastatic breast cancer were treated with mitoxantrone as a single agent, with the use of an intensive dose-escalating schedule. Doses were given at 0.5 mg/m2/day as an iv injection for 3 consecutive days and then were escalated each month by 2.5 mg/m2/day until maximal tolerance was reached on the basis of hematologic or cardiac toxicity. No complete responses were demonstrated. Six patients (22%) had partial responses of 5.5 months' median duration. Four of 12 patients who had not received prior doxorubicin responded (33%), whereas two of 15 patients with previous doxorubicin exposure responded (13%). Cardiotoxicity, determined by serial radionuclide ventriculography, occurred in 10 patients (37%) at a mean total mitoxantrone dose of 83.0 mg/m2. Three of these 10 patients had no predisposing risk factors, four had received thoracic radiotherapy that might have involved the heart, and three had received prior doxorubicin without clinical toxicity. The failure of dose intensification to augment the response rate when compared to the response rates reported for less myelotoxic doses of the drug, in addition to the extent of cardiotoxicity noted, calls into question the value of dose intensification of mitoxantrone in the treatment of metastatic breast cancer.

Psychological symptoms and disease-free and overall survival in women with stage II breast cancer. Cancer and Leukemia Group B.

BACKGROUND: The possible link between psychological factors and length of cancer survival has generated a literature of contradictory findings. Associations usually have not been found when general psychological symptoms are assessed. Associations usually have been found for predictors related to expressive versus repressive emotional coping (e.g., depression, "fighting spirit," hostility, and type C personality); however, even these associations have been relatively small, when compared with those for medical factors. Yet few studies have adequately controlled for medical and treatment-related factors. PURPOSE: Within a Cancer and Leukemia Group B (CALGB) national clinical trial of four adjuvant therapy regimens for stage II breast cancer (CALGB 8082), this study prospectively examined the contribution of potential psychological predictors to length of disease-free and overall survival over a 15-year period. METHODS: Subjects were 280 women with stage II breast cancer, out of a total of 899, who were randomly assigned to receive CMFVP (cyclophosphamide-methotrexate-fluorouracil-vincristine-prednisone) for two 6-week cycles or six 4-week cycles, then subsequently randomly assigned to receive or not to receive VATH (vinblastine-doxorubicin-thiotepa-fluoxymesterone). Subjects were recruited during the period between October 1980 and August 1984, inclusive, and followed until January 1996. Prior to chemotherapy, psychological symptoms were assessed using the Symptom Check List-90-Revised (SCL-90-R). SCL-90-R scores were trichotomized into categories representing high, medium, and low distress. Basic base-line sociodemographic data (including age, ethnicity, education, and marital status) and medical data (including lymph node status, estrogen receptor status, menopausal status, and performance status) were collected. Subjects with psychosocial data differed from those without psychosocial data solely in their higher percentage of classification in the mild limitation category of the Zubrod (Eastern Cooperative Oncology Group) performance status rating (subjects with psychosocial data: 14%; subjects without psychosocial data: 8%). RESULTS: In stepwise Cox regression analyses that controlled for sociodemographic and medical variables, there was no significant predictive effect of the level of distress (as measured by the SCL-90-R trichotomized scores) on length of disease-free and overall survival of the study subjects. Risk ratios for low versus high distress were 1.01 (95% confidence interval [CI] = 0.62-1.66) for disease-free survival and 1.03 (95% CI = 0.58-1.82) for overall survival. CONCLUSIONS: This study failed to provide evidence that psychological factors contributed to length of disease-free or overall survival of women who received adjuvant chemotherapy (either CMFVP alone or CMFVP followed by VATH) for treatment of stage II breast cancer. IMPLICATIONS: In the context of far more potent medical factors, the contribution of psychological factors to disease-free and overall survival is likely to be relatively small. Future research should focus on specific theory-driven predictors rather than on general psychological symptoms. Moreover, it should be based on clinical studies using a controlled, prospective design, in which the effects of medical factors may be distinguished and psychological predictors are clear antecedents of survival outcomes.

Reversal of drug sensitivity in multidrug-resistant tumor cells by an MDR1 (PGY1) ribozyme.

In order to reverse P-glycoprotein-mediated drug resistance in a specific manner, we designed two hammerhead ribozymes which can cleave the GUC sequence in codon 179 and 196 of MDR1 (PGY1) mRNA. The ribozymes were directly synthesized using a set of primers, one containing a bacteriophage T7 RNA polymerase promoter. A target MDR1 RNA was created by a reverse transcription polymerase chain reaction using a MOLT-3 human acute leukemia cell line resistant to trimetrexate (TMQ) (MOLT-3/TMQ800), which displayed MDR1 overexpression. In a cell-free system, both ribozymes cleaved a target piece of MDR1 RNA into 2 fragments at the specific sites at a physiological pH and temperature. The cleavage reaction was dependent on time, ribozyme:substrate ratio, and magnesium concentration. The 196 MDR1 ribozyme was more active than the 179 MDR1 ribozyme. The 196 MDR1 ribozyme was then cloned into a human expression vector, and MOLT-3/TMQ800 cells were transfected. The original MOLT-3/TMQ800 cells were nearly 700-fold resistant to vincristine, whereas the transfectant cells selected in G418 became only 20- to 30-fold resistant. The level of resistance and the amount of MDR1 RNA expressed appeared to correlate inversely with the amount of ribozyme expression. A disabled 196 MDR1 ribozyme was capable of neither specific cleavage in vitro nor decreasing MDR1 expression in transfectant cells. These results indicate that it was the ribozyme activity and not antisense activity which was responsible for decreased MDR1 RNA. This approach may be applicable to cancer patients as a specific means to reverse tumors with P-glycoprotein-mediated MDR phenotype back to a drug-sensitive one.

Effects of vincristine in combination with methotrexate and other antitumor agents in human acute lymphoblastic leukemia cells in culture.

The effects of vincristine (VCR) in combination with methotrexate (MTX) and other antitumor agents were evaluated by cell growth inhibition assay using a human acute lymphoblastic leukemia cell line (MOLT-3). The data were analyzed with the aid of an isobologram using the concept of an envelope of additivity (G. G. Steel and M. J. Peckman, Int. J. Radiat. Oncol., 5:85-91, 1979). Simultaneous exposure of VCR and MTX produced subadditive or mutually protective interactions. Sequential exposure to VCR first followed immediately by MTX produced similar interactions. When the interval of VCR exposure first and then MTX was increased from 0 to 3, 8, and 24 h, the inhibition of cell growth moved from protection and subadditivity to additivity only. The reversed order of exposure to the 2 drugs produced an entirely different picture. Thus, when the interval of MTX exposure first followed by VCR increased from 0 to 3, 8, and 24 h, the inhibitory effects of the combination changed progressively from the area of subadditivity to the area of supraadditivity. When these data were evaluated using median effect plot analyses (T-C. Chou and P. Talalay. In: New Avenues in Developmental Cancer Chemotherapy, pp. 36-64. Orlando, FL: Academic Press, 1987), strongly synergistic interaction of this sequence at space intervals was confirmed. These data show that the synergistic effects were produced only when MTX was followed 8 or 24 h later by VCR. Other schedules were only additive or even antagonistic. Simultaneous exposure of VCR with daunorubicin, 1-beta-D-arabinofuranosylcytosine, or bleomycin also had subadditive and protective effects. VCR, followed by daunorubicin with the interval of 24 h and vice versa, was again subadditive and protective. VCR, followed by 1-beta-D-arabinofuranosylcytosine with the interval of 24 h and vice versa, was again subadditive or additive only. Simultaneous and continuous exposures of VCR with vinblastine or L-asparaginase were only marginally supraadditive.

Pharmacological and therapeutic efficacy of daunomycin:DNA complex in mice.

The pharmacological and therapeutic effects of the daunomycin (DNM):DNA complex were compared with those of free DNM in mice. A complex formation between dnm and DNA (1:11.7, w/w) resulted in a 79% decrease in DNM complex was dialyzable. The DNM fluorescence was completely recovered from the complex in 0.3 N HCl and 50% ethanol solution, and a short contact with biological tissues studied did not quench DNM fluorescence after extraction. The plasma fluorescence (DNM equivalent) 5 min after the i.v. injection of DNM:DNA complex at a dose of 20 mg/kg was 60-fold higher than that of an equivalent amount of free DNM. The complex was cleared for plasma with an initial half-life of 20 min. In spite of an initally higher blood generally similar except in liver and spleen, where DNM equivalent were significantly higher than those of free DNM. The uptake of DNM:DNA into L1210 cells in vitro was low and, at 1 hr, was about one-twentieth of that from DNM. Treatment of DBA/2 mice bearing i.p. L1210 leukemia transplant (initial cell number, 10-3) with DNM:DNA complex resulted in identical increases in life-span as occurred with free DNM. When routes of cell transplant and treatment were different, no therapeutic advantage of DNM:DNA over DNM was seen.

Benzo(a)pyrene hydroxylase activity in enriched populations of Clara cells and alveolar type II cells from control and beta-naphthoflavone-pretreated rats.

We have developed a method for isolation and purification of specific types of lung cells from rats. Alveolar type II cells were purified from 18% in the initial cell digest to 30% after centrifugal elutriation and finally to over 80% following density gradient centrifugation. Clara cells were enriched from 0.8% in the cell digest to 40 to 60% by use of centrifugal elutriation. In control animals, aryl hydrocarbon hydroxylase activity was found to increase in parallel with Clara cell purity but was almost undetectable in the type II cells. Following pretreatment of rats with beta-naphthoflavone, aryl hydrocarbon hydroxylase activity increased both in Clara cells and particularly, in alveolar type II cells. This methodology provides a means for investigation of the effects of toxic and carcinogenic compounds on different populations of lung cells.

Pharmacokinetics of vindesine given as an intravenous bolus and 24-hour infusion in humans.

The pharmacokinetics of vindesine was examined after the determination of serum drug levels by radioimmunoassay in patients who received the drug either as an i.v. bolus or a 24-hr infusion. After i.v. bolus, vindesine was eliminated from the serum by triphasic decay. The central compartment was approximately 6 times the serum volume. The peak serum level achieved by i.v. bolus was approximately 16 times that achieved by the 24-hr infusion. The post-24-hr-infusion serum decay followed biphasic decay. Pharmacokinetic modeling, assuming a prolonged infusion period, resulted in a triphasic decay curve, with an extremely short distribution phase which would not be clinically detectable. This was due to the incorporation of the distribution phase into the infusion period. This explains the experimental data of a biphasic decay curve observed after 24-hr infusion. Pharmacokinetic parameters for the two phases observed after 24-hr infusion were similar to values calculated from i.v. bolus data. The c X t for 24-hr infusion was identical to that after i.v. bolus; theoretically, the c X t appears constant regardless of infusion time. It is concluded that the rate of elimination and/or the c X t, rather than the peak serum level, played a role in the degree of hematological toxicity.

Protein kinase C activity and multidrug resistance in MOLT-3 human lymphoblastic leukemia cells resistant to trimetrexate.

It has been suggested that protein kinase C (PKC) plays a role in multidrug resistance (MDR). In this study we assayed PKC activity in MOLT-3 human acute lymphoblastic leukemia cells and found an approximately 50% decrease in activity in MDR sublines made resistant to the lipophilic antifolate trimetrexate, when compared with trimetrexate-sensitive parent cells. The PKC activity of a methotrexate-resistant subline without MDR (MOLT-3/MTX10,000) was identical to that of parent cells. Although a downward trend was noted in PKC activity in the membrane fraction of cells with increasing trimetrexate resistance, there was no absolute correlation between the degree of MDR and the relative decrease in PKC activity. Using the same method, we also confirmed an over 6-fold increase in PKC activity in the MDR human breast cancer subline MCF-7/DOXR when compared with the sensitive parent cell line, MCF-7/WT. Because of this divergent relationship between relative PKC activity and MDR, we tested the effect of PKC inhibition and activation on drug resistance. The PKC inhibitor staurosporine, at both subtoxic and toxic concentrations as well as at concentrations shown to be inhibitory to PKC, failed to increase drug resistance of parent and resistant MOLT-3 cells and decrease drug resistance of MCF-7/WT and MCF-7/DOXR cells. Short-term exposure to 3-phorbol-12-myristate-13-acetate, which activated PKC 7.0-fold and 4.7-fold, respectively, in the membrane of MOLT-3 and resistant cells, resulted in small (1.3- to 1.8-fold), approximately equivalent, increases (rather than decreases) in resistance to doxorubicin, whereas for vincristine no consistent trend was observed. Identical results were also obtained with phorbol-12,13-dibutyrate. These results indicate that PKC activity can be decreased and increased in MDR cells. Both staurosporine inhibition and phorbol ester activation failed to produce changes in drug resistance that would be considered consistent with the resulting degree of PKC activity. Short-term phorbol ester exposure can change the sensitivity of the cells to doxorubicin without changing the relative drug resistance. PKC activity in these cells may then be unrelated to MDR.

Multidrug resistance in a human leukemic cell line selected for resistance to trimetrexate.

Trimetrexate (TMQ) is a lipophilic antifolate shown to have antitumor activity in humans. TMQ-resistant sublines of the MOLT-3 human acute lymphoblastic leukemia cell line were developed and were designated as MOLT-3/TMQ200, MOLT-3/TMQ800, and MOLT-3/TMQ2500 based on degrees of resistance to TMQ. The TMQ resistance was accompanied by 5- to 7-fold increases in dihydrofolate reductase activity and markedly reduced cellular TMQ accumulation. Methotrexate accumulation was not impaired in TMQ-resistant cells. TMQ retention (efflux) was unchanged in these TMQ-resistant cells. Verapamil enhanced the TMQ accumulation in the resistant cells to the level seen in the parent cells but had no effects on the TMQ retention. These sublines were cross-resistant not only to methotrexate but also to vincristine, doxorubicin, daunorubicin, and mitoxantrone. There was no cross-resistance to bleomycin or cisplatin. Resistance to vincristine, doxorubicin, daunorubicin, and mitoxantrone was reversed by verapamil. TMQ resistance was only minimally reversed by verapamil and methotrexate resistance not affected at all. Both cellular accumulation and retention of vincristine and daunorubicin in the TMQ-resistant cells were markedly decreased. Verapamil enhanced both accumulation and retention of the drug. Plasma membrane fractions of the TMQ-resistant cells analyzed by urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by staining with Coomassie Blue revealed the presence of a distinct band with a molecular weight of 170,000. Immunoblot analysis with 125I-labeled monoclonal antibody raised against P-glycoprotein of multidrug-resistant Chinese hamster ovary cells (C219) cross-reacted with the Mr 170,000 protein of the TMQ-resistant cells. These results show that the TMQ-resistant cells displayed not only decreased TMQ uptake and increased dihydrofolate reductase but also characteristics associated with a classical multidrug-resistant phenotype. Multidrug resistance includes lipophilic antifolate.

Mitoxantrone, vincristine, and prednisone in adults with relapsed or primarily refractory acute lymphocytic leukemia and terminal deoxynucleotidyl transferase positive blastic phase chronic myelocytic leukemia.

A combination of mitoxantrone, vincristine, and prednisone was used to treat 19 patients with acute lymphocytic leukemia. Of these, 12 were patients with acute lymphoblastic leukemia (ALL) (9 in first relapse and 5 primarily refractory to standard induction therapy with daunorubicin, vincristine, and prednisone), 2 had a phenotypic ALL relapse after an initial diagnosis of acute myelocytic leukemia and 5 had terminal deoxynucleotidyl transferase positive blastic phase chronic myelogenous leukemia (BCML). Eight patients with ALL (and of these, four with primarily anthracycline resistant disease), and two with BCML achieved complete remission. Five patients died in induction (three ALL from sepsis and two BCML from bleeding), and five had progressive disease. Median duration of response was 5 months, with two primarily refractory ALL patients remaining in continuing complete remission at 28 and 31 months. Treatment was well tolerated, with minimal nausea and vomiting, and oral mucositis. Posttreatment transient hepatic dysfunction was seen in 80% of patients. Mitoxantrone, vincristine, and prednisone are an active combination for the treatment of relapsed or refractory ALL and of terminal deoxynucleotidyl transferase positive BCML. The finding that four of five primarily refractory ALL patients were induced in complete remission supports the contention that mitoxantrone and anthracyclines are not cross-resistant.

Selective tumor apoptosis by MF13, L-prolyl-L-m-[bis(chloroethyl)amino]-phenylalanyl-L-norvaline ethyl ester, a new sarcolysin containing tripeptide.

ID50 and ID90 values for L-prolyl-L-m-[bis(chloroethyl)amino]-phenylalanyl-L-norvaline ethyl ester HCl (MF13), were determined in four murine (leukemia, lymphoma, melanoma, and lung) and eight human cancer cell lines (two leukemia, prostate, kidney, colon, two melanoma, and breast). Cytotoxic activity was 2-5 times higher than that of sarcolysin [(L-3-[bis(2-chloroethyl)amino]-L-phenylalanine] against all leukemias and lymphomas, ID50 0.5-0.9 microM, and against human solid tumors, ID50 0.4-2.1 microM. Sensitivities of L-phenylalanine mustard-resistant and methotrexate-resistant L1210 cells were the same as the naive lines, ID50 0.5 microM. Apoptosis was confirmed by: (a) morphology, revealing chromatin condensation and nuclear fragmentation; (b) flow cytometry, showing changes in cell size and DNA integrity; and (c) DNA electrophoresis, demonstrating multiples of 180-200-bp DNA units. MF13 had no cytotoxicity against human peripheral blood lymphocytes at concentrations lethal to tumor cells (ID50, 13.3 microM without and 11 microM with phytohemagglutinin stimulation) and failed to induce apoptosis. s.c. MF13 treatment of mice with advanced EL4 leukemic ascites yielded extensive apoptosis, with DNA degradation identical to that seen in vitro, and resulted in complete tumor regression in all treated mice. These results suggest MF13 as a potential chemotherapeutic agent.