Constipation and diarrhea: the neglected symptoms

OBJECTIVE

To review the symptom experience of constipation and diarrhea related to cancer and its treatment.

DATA SOURCES

Published articles and book chapters relating to constipation and diarrhea in patients with cancer.

CONCLUSIONS

Constipation and diarrhea often represent a major concern and source of discomfort for the cancer patients. Research is needed to establish prevention and treatment protocols for patients at risk for constipation or diarrhea.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses are in an excellent position to recognize individuals who are at high risk for constipation and diarrhea. Preventive strategies and treatment protocols are of utmost importance.

Laevofolinic acid, 5-fluorouracil, cyclophosphamide and escalating doses of epirubicin with granulocyte colony-stimulating factor support in locally advanced and/or metastatic breast carcinoma: a phase I-II study of the Southern Italy Oncology Group (GOIM)

Sixty-four consecutive patients with locally advanced (n = 7) or metastatic breast cancer (n = 57), were treated with a combination of laevofolinic acid 100 mg m-2 plus 5-fluorouracil 340 mg m-2 i.v. on days 1-3, cyclophosphamide 600 mg m-2 i.v. on day 1 and epirubicin 90 mg m-2 i.v. on day 1. Epirubicin dose was progressively escalated by 10 mg m-2 per cycle up to 120 mg m-2 in the absence of dose-limiting toxicities. Granulocyte colony-stimulating factor (G-CSF) was given subcutaneously in order to prevent neutropenia. Epirubicin dosage could be increased to 100 mg m-2 in 53 patients (87%), to 110 mg m-2 in 31 patients (51%) and to 120 mg m-2 in 18 cases (30%). In most patients the dose-limiting toxicity was represented by myelosuppression. A statistically significant correlation was found between median white blood count (WBC) or absolute neutrophil count (ANC) nadir and epirubicin dose level (P = 0.009; P = 0.008). Moreover, a statistically significant correlation was observed between the number of chemotherapeutic cycles, nadir ANC and WBC and the occurrence of anaemia and thrombocytopenia of increasing severity. These data suggest the occurrence of progressive cumulative bone marrow toxicity. Although patients who reached different epirubicin levels showed differences in mean dose intensity, such differences were not statistically significant. No correlation was found between the increase in dose intensity and type, rate or duration of objective responses. In patients with metastatic breast cancer the overall response rate was 72% (95% CL 66-78%) with a 25% complete response rate. Median duration of response was 10 and 13 months respectively for complete and partial responses. All patients with locally advanced breast cancer had an objective response and underwent radical mastectomy. Projected median survival of the whole series of patients with metastatic breast cancer was 20 + months. These data demonstrate that the combination of 5-fluorouracil with laevofolinic acid, cyclophosphamide and epirubicin is very active against metastatic breast cancer. Use of G-CSF allows epirubicin dosage to be increased up to 120 mg m-2 cycle-1, but its use may be linked to the occurrence of sometimes severe cumulative haematological toxicity.

Effects of bryostatin-5 and hematopoietic growth factors on acute myeloid leukemia cell differentiation, proliferation, and primary plating efficiency

We examined the effect of bryostatin-5 (bryo-5) with and without a combination of myeloid growth promoting factors on human acute myeloid leukemia (AML) cell growth, maturation, and primary plating efficiency. In vitro treatment of AML samples with bryo-5 induced a macrophage-like cell differentiation as evidenced by morphological changes, esterase staining, and cell surface expression of CD11a and CD18. AML cells exposed to growth factors doubled their cell numbers following culture, this increase being abrogated by co-exposure to bryo-5. An antiproliferative effect, as well as the antagonistic interaction of bryo-5 with growth factors, was confirmed in methylcellulose clonogenic assays. Together, these findings indicate that the compound bryo-5 exerts an anti-proliferative effect on AML cells and counteracts growth factor induced leukemic proliferation.

A phase I trial of bryostatin 1 in patients with advanced malignancy using a 24 hour intravenous infusion

Bryostatin 1 is a macrocyclic lactone derived from the marine invertebrate Bugula neritina. In vitro, bryostatin 1 activates protein kinase C (PKC), induces the differentiation of a number of cancer cell lineages, exhibits anti-tumour activity and augments the response of haemopoietic cells to certain growth factors. In vivo, bryostatin 1 is also immunomodulatory, but the range of tumours which respond to bryostatin 1 in xenograft tumour models is mostly the same as the in vitro tumour types, suggesting a direct mode of action. Nineteen patients with advanced malignancy were entered into a phase I study in which bryostatin 1 was given as a 24 h intravenous infusion, weekly, for 8 weeks. Myalgia was the dose-limiting toxicity and the maximum tolerated dose was 25 micrograms m-2 per week. The myalgia was cumulative and dose related, and chiefly affected the thighs, calves and muscles of extraocular movement. The mechanism of the myalgia is unknown. CTC grade 1 phlebitis affected every patient for at least one cycle and was caused by the diluent, PET, which contains polyethylene glycol, ethanol and Tween 80. Most patients experienced a 1 g dl-1 decrease in haemoglobin within 1 h of commencing the infusion which was associated with a decrease in haematocrit. Radiolabelled red cell studies were performed in one patient to investigate the anaemia. The survival of radiolabelled red cells during the week following treatment was the same as that seen in the week before treatment. However, there was a temporary accumulation of radiolabelled red cells in the liver during the first hour of treatment, suggesting that pooling of erythrocytes in the liver might account for the decrease in haematocrit. Total or activated PKC concentrations were measured in the peripheral blood mononuclear cells (PBMCs) of three patients for the first 4 h of treatment and during the last hour of the infusion. This showed that PKC activity was significantly modulated during the infusion. Bryostatin 1 is immunomodulatory in vitro, and we have confirmed this activity in vivo. An investigation of the first three cycles of treatment in seven patients showed an increased IL-2-induced proliferative response in peripheral blood lymphocytes and enhanced lymphokine-activated killer (LAK) activity. A previously reported rise in serum levels of interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF 1) was not confirmed in our study; of nine patients in this study, including patients at all dose levels, none showed an increase in these cytokines.(ABSTRACT TRUNCATED AT 400 WORDS)

Review of survival analyses published in cancer journals

Survival analysis has found widespread applications in medicine in the last 10-15 years. However, there has been no published review of the use and presentation of survival analyses. We have carried out a systematic review of the research papers published between October and December 1991 in five clinical oncology journals. A total of 132 papers were reviewed. We looked at several aspects of study design, data handling, analysis and presentation of the results. We found that almost half of the papers did not give any summary of length of follow-up; that in 62% of papers at least one end point was not clearly defined; and that both logrank and multivariate analyses were frequently reported at most only as P-values [63/84 (75%) and 22/47 (47%) respectively]. Furthermore, although many studies were small, uncertainty of the estimates was rarely indicated [in 13/84 (15%) logrank and 16/47 (34%) multivariate results]. The procedure for categorisation of continuous variables in logrank analyses was explained in only 8/49 (16%) papers. The quality of graphs was felt to be poor in 43/117 (37%) papers which included at least one survival curve. To address some of the presentational inadequacies found in this review we include new suggested guidelines for the presentation of survival analyses in medical journals. These would complement the statistical guidelines recommended by several clinical oncology journals.

Effect of cisplatin in advanced colorectal cancer resistant to 5-fluorouracil plus (S)-leucovorin

Modulation of 5-fluorouracil (5-FU) is currently being investigated in advanced colorectal cancer. In an attempt to improve the results obtainable for the association of 5-FU and leucovorin, we decided to add cisplatin to 5-FU and (6S)-leucovorin (S-LV) after disease progression. The hypothesis was that a pharmacological enhancement of the efficacy of 5-FU would result in responses in 5-FU-unresponsive patients or in a second response in previously responding patients. A group of 28 5-FU+S-LV-pretreated patients, with advanced measurable colorectal cancer, were treated with 80 mg/m2 cisplatin on day 1, 80 mg/m2 S-LV and 370 mg/m2 5-FU as an i. v. bolus for 5 consecutive days every 4 weeks. We obtained 3 partial responses (response rate: 11 +/- 11%), while 11 patients had stable disease (39 +/- 18%). Among the 3 responders, 1 patient had earlier achieved a partial response, a second stable disease and 1 had disease progression after the previous 5-FU+S-LV treatment. The median survival time for all 28 patients was 11 months. Toxicity was minimal and consisted of mild and reversible gastrointestinal symptoms and myelosuppression. We believe that further studies must be carried out to establish the real impact of the synergism between cisplatin, 5-FU and S-LV in untreated patients.

Consensus statement: octreotide dose titration in secretory diarrhea. Diarrhea Management Consensus Development Panel

Octreotide is an effective therapeutic option in controlling secretory diarrhea of varied etiology. However, marked patient-to-patient differences in the antidiarrheal effects necessitate titration of octreotide dose in individual patients to achieve optimal symptom control. A consensus development panel established guidelines for octreotide dose titration in patients with secretory diarrhea. Overall, the panel recommended an aggressive approach in selecting the initial octreotide dose and in making subsequent dose escalations in patients with secretory diarrhea due to gastrointestinal tumors (eg, carcinoids, VIPomas), AIDS, dumping syndrome, short bowel syndrome, radiotherapy, or chemotherapy. To avoid hypoglycemia in patients with diabetes mellitus-associated secretory diarrhea, the panel recommended a low initial octreotide dose and a conservative titration regimen with close monitoring a blood glucose levels. The end point of therapy should focus on a reduction in diarrhea (frequency of bowel movements or stool volume) rather than normalization of hormonal profile. Overall, octreotide is well tolerated; principal side effects are transient injection site pain and gastrointestinal discomfort. For many patients with secretory diarrhea, octreotide therapy is expected to improve the overall health and quality of life and in the long run will lessen health care costs.

Undifferentiated nasopharyngeal cancer (UCNT): current diagnostic and therapeutic aspects

Undifferentiated carcinoma of the nasopharynx (UCNT) is a particular head and neck epidermoid lineage tumor related to the Epstein Barr Virus (EBV). It has geographically selective endemic epidemiologic features, without relation to external carcinogens. Its systemic agressiveness is the source of most disease-related demises, because radiotherapy achieves excellent local control and a significant percentage of cure in patients with exclusive locoregional disease. Difference in the staying systems currently in use, the recent changes in imaging and radiotherapy technology, and the lack of distinction between UCNT and squamous cell carcinoma (SCC) of the nasopharynx in Western literature reports make for some difficulty in therapeutic results evaluation when analyzing available literature. Its chemosensitivity is a relatively recent acknowledged fact, and its use in metastatic patients results in a high percentage of objective responses, many of long duration. Neoadjuvant cisplatin-based chemotherapy seems to be of benefit, but outstanding controversies in this regard will be soon answered through ongoing phase III trials. After a review of the current literature of all the above-mentioned aspects of this fascinating nosologic entity, our own experience, both in metastatic and locoregional disease patients is analyzed.

Effect of cisplatin administration on the proliferation and differentiation of bone marrow cells of tumour-bearing mice

In the present study the effect of tumour growth with respect to two tumour systems (Dalton's lymphoma [DL] and P815) on the in vitro, colony-forming ability (CFA) and proliferation of the bone marrow cells (BMC) of C3H/He mice was investigated. The P815-bearing mice showed an enhanced bone marrow colony forming ability in vitro, in response to L929 conditioned medium (L929 CM) used as a source of CSF. On the other hand, DL-bearing mice did not have any significant alteration in this process compared to normal mice. In vivo, administration of cisplatin resulted in a significant rise in the CFA of normal as well as DL- or P815-bearing mice. The tumour-conditioned medium (TCM) and ascitic fluid (AF) of P815 but not of DL, was found to support the in vitro colony formation of BMC obtained from cisplatin-treated or untreated mice. The number of CFU-granulocyte-macrophage was predominantly high in the cultures of BMC incubated with TCM or AF of P815. The TCM and AF of P815 also enhanced the in vitro proliferation of BMC obtained from cisplatin-treated or untreated mice. In vivo, administration of cisplatin in normal mice resulted in enhanced numbers of peritoneal exudate macrophages (PEM) and PBL. Similarly, the number of PEM and PBL was augmented in both the P815- and DL-bearing mice. However, cisplatin administration in the tumour-bearing mice decreased the count of PEM, while the number of leucocytes remain unaffected. This study indicates that the cancer chemotherapeutic drug cisplatin can influence the differentiation of the bone marrow progenitor cells in response to tumour growth in situ.

A phase II trial of mitoxantrone plus cyclophosphamide and 5-fluorouracil in modulation with levo-folinate for advanced breast cancer patients

Advanced breast cancer remains a major clinical problem. Current chemotherapy regimens are able to induce a clinical response in many patients but do not appear to influence significantly patients' survival. The use of new drugs such as mitoxantrone with a predicted lower toxicity and biochemical modulation of 5-fluorouracil with levo-folinate are extensively studied research areas that could combine good therapeutic efficacy with the maintenance of an acceptable quality of life. 34 patients with advanced breast carcinoma were included in the study. Only 4 women had received prior chemotherapy for advanced disease. Treatment plan was: 5-fluorouracil 400 mg/m2 + l-leucovorin 100 mg/m2 days 1-3, cyclophosphamide 600 mg/m2 and mitoxantrone 12-14 mg/m2 on day 3, q28. G-CSF (5 micrograms/kg/d days 7-14) was routinely delivered to the patients with the aim of maintaining dose intensity. 15 patients obtained a response for an overall response rate of 44%. Mean duration was 10.2+ and 11+ months for complete and partial responses respectively. Mean overall survival was 14.4+ months. A high complete response rate was seen in liver metastasis (44%), while lung lesions had a lower probability of response (25%). Toxicity was globally mild with 23% of grade 3 vomiting and 15% of grade 3-4 leukopenia. Two cases of cardiotoxicity were reported. No difference in response rate or toxicity was identified between patients receiving two different mitoxantrone doses (12 or 14 mg/m2). The schedule employed appears to be well tolerated and active in the treatment of advanced breast cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

A fixed-ratio combination of uracil and Ftorafur (UFT) with low dose leucovorin. An active oral regimen for advanced colorectal cancer

BACKGROUND

UFT is a fixed-ratio combination of uracil and Ftorafur, a prodrug that is absorbed orally and metabolized in vivo to 5-fluorouracil (5-FU). Uracil potentiates 5-FU through interference with its catabolism. The combination of UFT and leucovorin in patients with advanced incurable colorectal cancer, to evaluate preliminary activity and toxicity in this patient population.

METHODS

Twenty-one patients were treated. Twenty patients were evaluable for toxicity and response. Patients received UFT 350 mg/m2/day divided every 8 hours. Patients took a 5 mg tablet of leucovorin every 8 hours, concurrent with each UFT dose. Treatment was continued for 28 consecutive days, followed by a 7-day rest.

RESULTS

Five major objective responses (one complete and four partial) were observed. Toxicity was mild, with no dose-limiting myelosuppression. Four patients experienced grade 3 diarrhea or higher, and two patients experienced dose-limiting mucositis.

CONCLUSION

UFT and low dose leucovorin is a well tolerated, orally administered regimen with activity in colorectal cancer. A randomized comparison of this regimen with conventional parenteral regimens is warranted.

Phase II trial of an all-oral regimen of tegafur and folinic acid in patients with previously treated metastatic breast cancer

BACKGROUND

Tegafur is an antimetabolite slowly metabolized to 5-fluorouracil in vivo. Protracted administration of oral tegafur is active in metastatic breast cancer, with reported response rates ranging from 29 to 44%. The addition of folinic acid could improve the efficacy of tegafur by means of biochemical modulation.

METHODS

A prospective Phase II trial in patients with pretreated metastatic breast cancer was performed. The regimen consisted of oral tegafur (750 mg/m2/day) and oral folinic acid (45 mg/day) for 21 days, recycling at day 28.

RESULTS

Twenty-five patients were included. Eight partial responses were observed for an objective response rate of 32% (95% confidence intervals for response, 23-41%). The median duration of response was 7 months. According to WHO criteria, 24% of patients experienced grade 3 mucositis and 12% grade 3 diarrhea, but no other significant toxicities were observed. Twenty-eight percent of patients required dose reductions for toxicity.

CONCLUSIONS

A significant response rate with oral tegafur and folinic acid in patients with heavily pretreated breast cancer was found. This all-oral regimen, which could be safely administered on an outpatient basis, deserves further evaluation to define the role of folinic acid on the activity of tegafur in metastatic breast cancer.

Different dose regimens of 5-fluorouracil and interferon-alpha in patients with metastatic colorectal carcinoma

Three different 5-fluorouracil (5-FU)-interferon-alpha-2b (IFN)-containing regimens were designed for treatment of patients with advanced colorectal cancer. 87 patients with a Karnofsky index > or = 70 were included in three sequential non-randomised phase II trials. Regimen A consisted of 5-FU (750 mg/m2/day) given as a continuous infusion on days 1-5 followed by weekly 1-h intravenous infusions until week 8. IFN (5 MU) was given subcutaneously on days 1, 3 and 5 followed by injections (9 MU) every second day until week 8. The cycle was then repeated. Regimen B consisted of 5-FU (750 mg/m2/day) given as a continuous infusion on days 1-5 followed by 5-min intravenous injections on days 12 and 19. IFN (3 MU) was given subcutaneously on days 1-5 followed by injections (5 MU) on days 11-13 and 18-20. The cycle was repeated every fourth week. Regimen C consisted of 5-FU (750 mg/m2/day) given as a continuous infusion on days 1-5. IFN (3 MU) was given subcutaneously on days 1-5. The cycle was repeated every third week. The objective response rates (complete response (CR) and partial response (PR)) after approximately 4 months of therapy or longer were as follows: regimen A (n = 27) 22% (2 CR, 4 PR), regimen B (n = 33) 42% (4 CR, 10 PR) and regimen C (n = 27) 22% (1 CR, 5 PR). The corresponding response figures for previously untreated patients were regimen A 50%, regimen B 64% and regimen C 38%. Response durations varied from a few weeks up to 142 + weeks. Toxicities were generally mild and reversible, and the treatments were convenient for the patients and cost effective since the 5-day infusions could be given by a portable pump without hospitalisation. Our results are in agreement with those of others showing that 5-FU/IFN combinations can be highly effective in advanced colorectal cancer, and that a number of factors such as doses, dose intensities, infusion rates and timing of the two drugs may be crucial for the anti-tumour activity of this drug combination.

The mode of inhibition of human erythrocyte membrane-bound acetylcholinesterase by cisplatin in vitro

The effect of the well known anticancer drug "cisplatin" on the human erythrocyte membrane-bound acetylcholinesterase (AChE) has been investigated. It was found that cisplatin has inhibitory activity against AChE. Cisplatin (0.5-7.0 mM) inhibited AChE activity (27-82%) in a concentration dependent manner. The nature of the inhibition of AChE by cisplatin was complex and involved a partial reversible stage followed by a slow acting irreversible step. The inhibition was independent of a preincubation period up to 90 min while becoming dependent after this period. By diluting the preincubated AChE-cisplatin mixture for different times (0-24 h), the inhibition was partially reversed but again increased progressively with incubation time, ultimately reaching complete inhibition. The effect of increasing substrate concentration had the same behaviour as the dilution effect.

Bryostatin-5 stimulates normal human hematopoiesis and inhibits proliferation of HL60 leukemic cells

In this study we explored the effects of bryostatin-5 on the clonogenic response of normal bone marrow mononuclear (BM) cells and HL60 myeloid leukemia cells. Leukemic HL60 colony formation was strongly inhibited by bryostatin-5 depending on dose and schedule. An inhibitory effect on HL60 colony formation was readily demonstrated after 1 h of exposure, reaching a maximal inhibitory effect at 96 h. Normal BM cells differed in their clonogenic response: short-term exposure to bryostatin-5 resulted in increased clonogenicity while longstanding exposure to bryostatin-5 permitted the survival of a substantial fraction of committed progenitors. This differential modulation of normal and leukemic myeloid clonogenicity by bryostatin-5 suggests a possible role for bryostatin-5 in the treatment of acute myeloid leukemia.

Immunomodulation in patients receiving intravenous Bryostatin 1 in a phase I clinical study: comparison with effects of Bryostatin 1 on lymphocyte function in vitro

Bryostatin 1 is a protein kinase C activator that inhibits growth of tumour cells and activates lymphocytes in vitro, properties that have encouraged its use in phase 1 clinical studies as an anticancer agent. We investigated interleukin-2(IL-2)-induced proliferation and lymphokine-activated killer (LAK) cell activity in peripheral blood mononuclear cells (PBMC) from cancer patients receiving Bryostatin intravenously. After Bryostatin administration both LAK generation and proliferation were enhanced when patients' PBMC were stimulated with IL-2 in vitro. However, when normal donors' PBMC were cultured in vitro in the presence Bryostatin and IL-2, LAK induction was inhibited while IL-2-driven proliferation was increased. These effects were also seen following only 2 h exposure to Bryostatin and could be elicited by conditioned medium from Bryostatin-pretreated cells. Neither IL-4 nor interferon gamma was detected in the conditioned medium. Bryostatin in vitro was found to increase expression of IL-2 receptors on CD4+, CD8+ and CD56+ cells and augment the proportion of CD8+ cells in conjunction with IL-2. We conclude that Bryostatin in combination with IL-2 in vitro enhances proliferation and IL-2 receptor expression on lymphocytes, favouring CD8+ cells while suppressing the generation of LAK activity. Intravenous administration of Bryostatin increases the potential of IL-2 to induce proliferation and LAK activity in lymphocytes which, taken together with its putative direct antitumour effect, makes Bryostatin an interesting candidate for clinical trials in combination with IL-2.

Cytotoxic effect of butein on human colon adenocarcinoma cell proliferation

Several classes of plant polyphenols namely, flavonoids, chalcones and coumarins exhibited varying degrees of inhibition on the cell proliferation of human colon adenocarcinoma cell line 220.1. At the highest concentration tested (100 microM), many of the chalcones showed > 100% growth inhibition and their order of potency was butein > 2'-hydroxychalcone > 2-hydroxychalcone > 2',6'-dihydroxy-4'-methoxychalcone > 2',4-dihydroxychalcone with IC50 values of 1.75, 6.2, 7.5, 17, 23 microM, respectively. Butein (the most potent chalcone) at 2 microM concentration inhibited the incorporation of 14C-labelled thymidine, uridine and leucine into the colon cancer cells whilst 5-fluorouracil (5-FU, a chemotherapeutic drug) at 50 microM concentration could significantly inhibit only the uridine incorporation. The mode of cytotoxic action of butein was different from 5-FU but may be similar to colchicine, a known HeLa cell inhibitor.

Neo-adjuvant chemotherapy +/- immunotherapy with s.c. IL 2 in advanced squamous cell carcinoma of the head and neck: a pilot study

We carried out a pilot nonrandomized phase II study to compare the neo-adjuvant chemotherapic regimen with cisplatin, 5-FU and vinorelbine with the same combination plus s.c. IL 2 in advanced head and neck squamous cell carcinoma (HNSCC). The primary goals of the trial were to evaluate the feasibility and response rates of the two regimens. The study design consisted of a patient's assignment to either of the two following arms: Arm A: Cisplatin 80 mg/m2 i.v. on day 1; 5-FU 600 mg/m2 i.v. on days 2-5; and vinorelbine 20 mg/m2 i.v. on days 2 and 8, Arm B: the same chemotherapic regimen plus recombinant IL 2 (Proleukin, Eurocetus) 9 MIU s.c. daily from day 9 to 13 and from day 16 to 20 for every cycle. From March 1993 to November 1993 twenty three patients with Stage III-IV HNSCC were enrolled in the study. Patients could be evaluated for response to treatment if they had received at least 2 complete cycles of therapy. The overall response rate (ORR) was 63% in Arm A and 100% in Arm B. The differences for ORR and CR rates were statistically significant in favor of Arm B. The analysis for each of the three drugs included in the chemotherapy schedule shows that both the actually received average dose-intensity and the actually delivered average cumulative doses/patient were higher for Arm B (chemo-plus IL 2 therapy) (approximately 80% of programmed dose-intensity) than for Arm A (approximately 70% of programmed dose-intensity). Both the actually received average dose-intensity and the actually delivered average cumulative doses/patient for IL 2 were more than 80%. In both arms the most frequent side effects were myelosuppression, phlebitis and electrolyte disturbances. There were 2 toxic deaths, 1 in Arm A and 1 in Arm B, both for hematologic toxicity. Our "pilot" study suggests that the combination of cisplatin, 5-FU, vinorelbine plus IL 2 is a highly active, but rather toxic, neo-adjuvant treatment in advanced HNSCC with very high ORR and CR rates.

Role of protein phosphorylation in EPO-mediated early signal transduction: analysis in the EPO-reactive cell line ELM-I-1 transfected with a c-fos-enhancer/promoter-luciferase reporter gene

To investigate the role of protein phosphorylation in the early phase of EPO-mediated signal transduction, we EPO-stimulated a murine erythroid cell line ELM-I-1 transformed by plasmids comprised of the c-fos enhancer/promoter linked to the luciferase gene. Using this reporter gene system, we previously showed that EPO-induced activation of the c-fos promoter can be detected rapidly and sensitively as an elevation of cellular luciferase activity. In this study, we first examined the role of protein tyrosine phosphorylation. The tyrosine phosphatase inhibitor orthovanadate not only induced luciferase activity by itself but enhanced the action of EPO. On the other hand, the tyrosine kinase inhibitors erbstatin and herbimycin suppressed the effect of EPO. Next, the role of protein kinase C (PKC) in the EPO response was assessed. The PKC activator phorbol myristate acetate (PMA) not only induced luciferase activity by itself but enhanced the action of Epo. On the other hand, the PKC inhibitor 1-(5-isoquinolynyl-sulfonyl)-2-methylpiperazine (H7) suppressed the effect of Epo and PMA, whereas a nonspecific protein kinase inhibitor, N-(2-Guanidinoethyl)-5-Isoquinolinesulfornamine (HA1004) inhibited the action of neither Epo nor PMA. Another known PKC inhibitor staurosporine (STSP) did not inhibit but rather enhanced the effect of Epo. This action of STSP was blocked by H7 but not by HA1004. These results suggest that the EPO-mediated early signal transduction pathway leading to c-fos expression involves protein-tyrosine phosphorylation, is modulated by tyrosine phosphatase activity and is positively regulated by PKC.

A case of allergic liver injury induced by tegafur

A 51-year-old woman constitutionally susceptible to allergy presented with acute allergic liver injury. She was taking tegafur for treatment of carcinoma of the uterus. The acute liver injury appeared 3 weeks after the first drug administration. She had marked elevation of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT), moderate jaundice, and eosinophilia. The virus markers revealed hepatitis B surface antigen (HBsAg) (-) antibody to hepatitis B surface antigen (HBsAb) (+), and immunoglobulin M HA antibody (IgM HA Ab) (-). The laparoscopic and histologic findings were compatible with drug-induced liver injury. Further, the results of the lymphocyte stimulation test (LST) and challenge test by tegafur were positive. From the above findings, the liver injury was diagnosed to be an allergic reaction induced by tegafur. The hepatic function returned to normal about 20 days after tegafur administration was suspended. Allergic liver injury induced by tegafur is very rare. We report the case with a short review of the literature.

A phase I-II study of cyclophosphamide, epidoxorubicin, levofolinic acid/5-fluorouracil and recombinant human granulocyte colony stimulating factor in metastatic breast carcinoma

Thirty patients with measurable metastatic breast carcinoma were treated with a combination of cyclophosphamide 600 mg/m2 on day 1, levofolinic acid 100 mg/m2 plus 5-fluorouracil 375 mg/m2 on days 1-3, and epidoxorubicin (EDXR) in three refracted doses on days 1-3 with G-CSF rescue for 10 days. In the phase I part of the study, groups of 3 patients received EDXR 20, 25, 30, 35, and 40 mg/m2/day until the dose limiting toxicity (DLT) was reached. At the dose of 40 mg/m2/day prolonged grade 4 leukopenia, severe proctitis, and grade 3 diarrhea represented the DLT. All subsequent patients were treated at the maximal tolerated dose of EDXR (35 mg/m2/day). In the group of 18 patients treated at 35 mg/m2/day the overall response rate was 78%, with 22% CR and 56% PR. Four patients did not respond. Objective responses were seen at all tumor sites including bone and viscera, which usually are rather chemotherapy insensitive. Toxicity was generally acceptable. Although the response rate was quite high, the duration of objective tumor regression and patients' survival were not impressive. In conclusion, we do not recommend routine use of such an aggressive regimen for palliation of advanced breast cancer. Results of the present and similar studies may, however, be useful for planning of neoadjuvant or adjuvant trials with curative intent.

Preclinical and clinical aspects of biomodulation of 5-fluorouracil

Although single agent 5-FU has for many years been the standard therapy for advanced colorectal malignancies, a number of recent clinical trials show higher response rates with biomodulation of 5-FU by several different agents. In general, trials of leucovorin, methotrexate, interferon, and PALA given in biomodulatory doses and sequences with 5-FU have demonstrated comparable response rates over a broad range. However, in the absence of controlled direct comparative phase III trials, final judgement on clinical superiority of a particular regimen must be reserved. Nevertheless, on the basis of current data, certain approaches appear promising and warrant further investigation. Compared to single agent 5-FU, survival benefit has been demonstrated with both low and high dose leucovorin/5-FU regimens and response rates in the 20-50% range appear reproducibly higher than those of 5-FU alone. Low dose and either continuous infusion or repetitive dosing of leucovorin, as well as the effect of treatment sequence and intervals between drugs, require additional investigation. When given 20-24 h before 5-FU, methotrexate achieves response rates similar to leucovorin modulated 5-FU, but the potential role of rescue leucovorin used in many of the trials makes definitive interpretation difficult. Interferon/5-FU regimens attaining response rates of 30-40% are promising but need to be carefully and rationally designed. Low dose PALA with effective doses of 5-FU achieving responses in 35-45% of patients represent a marked improvement in earlier trials of high dose PALA, but additional studies with higher doses not compromising 5-FU dose intensity should be considered. Certainly, the concomitant use of multiple modulating agents also needs further investigation. While many such trials already performed attained results no better than single agent biomodulation, the preliminary results obtained by Grem and colleagues with IFN/LV/5-FU in untreated patients, and by Conti et al. using TMTX/LV/5-FU in previously treated patients are encouraging. Further understanding of the mechanisms of action and interaction of modulating agents should allow additional rational combinations to be explored clinically. Cisplatin biomodulation of 5-FU has been studied in gastrointestinal and head and neck malignancies achieving excellent results in the latter group. Preclinical evidence exists which suggests, however, that 5-FU modulation of cisplatin may be more effective, especially when 5-FU is administered 24 h or more before cisplatin. Clinical investigation of this sequence is currently lacking. Data to support the clinical promise of AZT, IdUrd, uridine, and the benzylacyclouridines are not yet available, although preclinical and preliminary clinical studies are promising.

The Discovery of Marine Natural Products with Therapeutic Potential

This chapter highlights the discovery of marine natural products with therapeutic potential. Deep water collections have been made by dredging and trawling. These are both cost-effective collection methods if the substratum does not cause damage to or snag the gear. There are several disadvantages to these approaches. It is difficult to photograph the organisms in their habitat, and encrusting organisms or organisms that grow in crevices, under ledges, or on steep rock faces cannot be easily collected unless the hard substrate that supports the organism is collected as well; dredging and trawling put all collected samples in close contact with each other and therefore, some organisms may chemically contaminate others because of exudations or secretions of various compounds and the environmental impact of dredging or trawling can be detrimental because the sampling is nonselective and habitats can be damaged or destroyed. A controversial facet of marine-derived microorganisms is their putative role with respect to the origin of bioactive natural products from marine macroorganism–microorganisms associations. Symbiotic microorganisms have been repeatedly suggested as being the direct or indirect sources of bioactive metabolites in marine sponges and other invertebrates, tunicates, and bryozoans.

Different biological effects of the two protein kinase C activators bryostatin-1 and TPA on human carcinoma cell lines

Bryostatin 1 (Bryo) is a naturally occurring macrocyclic lactone with antineoplastic activity. Like the phorbol ester 12-O-tetradecanoyl-phorbol 13-acetate (TPA) it directly activates the calcium- and phospholipid-dependent protein kinase C (PKC), thus generating a number of different cellular responses. We investigated the effects of Bryo and TPA on DNA synthesis, proliferation, viability and c-myc protooncogene expression of the human carcinoma cell lines COLO-320, MEL-HO, and KB-3-1. TPA inhibited [3H]-thymidine incorporation in all three cell lines in a dose-dependent manner, whereas Bryo only inhibited the DNA synthesis in MEL-HO, but not in KB-3-1 and COLO-320 cells. Within the concentration ranges used, TPA and Bryo were found to have a low toxicity. Counting of the cells confirmed the observed inhibition of cell proliferation. However, the enzymatic conversion of MTT, applied as a colorimetric proliferation assay, was not significantly affected by both biomodulators. Time-course experiments revealed a rapid onset of the inhibitory effect on DNA synthesis. Bryo was further able to antagonize the TPA-mediated effects on proliferation suggesting an (at least partially) different mode of action of these PKC activators. Incubation of MEL-HO and COLO-320 cells with either of the two biomodulators resulted in a rapid and strong increase of c-myc mRNA. The present study emphasizes Bryo as an interesting, natural substance for the study of PKC-mediated biological effects.

Vinorelbine in pre-treated advanced head & neck squamous cell carcinoma. A phase II study

BACKGROUND

There are few moderately active single-agents for the treatment of recurrent or metastatic head & neck cancer. Thus, the identification of novel active agents is warranted. We performed the present phase II trial to evaluate activity and toxicity of vinorelbine (VNB) in previously treated patients with advanced head & neck cancer.

PATIENTS AND METHODS

16 patients entered the study, 15 of whom were evaluable. The main characteristics were: M/F = 14/1; median age of 58 yrs (18-67); median PS (Karnofsky score) of 70 (60-100); primitive tumor sites were: oropharynx in 5; larynx in 4, hypopharynx in 3, rhynopharynx in 2, and oral cavity in 1 patient; initial clinical stage was IV in 9, III in 4 and II in 2 patients. Previous treatments were: cisplatinum with concurrent radiotherapy in 6 and cisplatinum + fluorouracil (for at least 2 cycles) in 9 patients. VNB was given at the dose of 20 mg/m2 i.v. infusion for 1 hr, weekly, for a minimum of 8 doses. Response and toxicity were evaluated after at least 8 doses of VNB.

RESULTS

Overall, 139 courses of VNB were given (median 9, range 8-19). Objective responses were: partial response in 1 patient (6%); stable disease, lasting at least 2 months, in 4 patients (27%) and progression in the other 10 patients (67%). Three patients had a one week delay in subsequent courses due to severe hematological toxicity. Toxicities observed were: leucopenia of grade IV (W.H.O.) in 2 patients and of grade I-II in 12 patients; granulocytopenia of grade III in 1 patient and of grade IV in 2 patients; grade I-II anemia in 4 patients; grade II phlebitis in 3 patients; grade II constipation in 2 patients, grade I-II peripheral neuropathy in 3 patients, grade I-II nausea and vomiting in 4 patients, and grade II stomatitis in 2 patients.

CONCLUSIONS

VNB, in this series of heavily pre-treated patients with head & neck cancer, did not reveal an antitumor activity of interest.

Nasopharyngeal carcinoma with brain metastasis: a case report

We report a case of nasopharyngeal carcinoma with brain metastasis of a 69-year-old man. The patient presented with blindness and a huge mass over right upper neck. The magnetic resonance imaging (MRI) showed right nasopharyngeal tumor and metastatic lesion in bilateral occipital regions. The bony x-ray showed diffuse osteoblastic metastases. The brain lesion was pathology-proven through the computed-tomographic guidance stereotactic biopsy.

Effects of diflubenzuron and clanfenur on mouse bone marrow cells

Diflubenzuron (DFB) and Clanfenur (CFN) belong to a group of compounds called Benzoylphenyl Ureas (BPUs). Several BPUs regulate cell growth in insects and/or inhibit growth of B-16 murine melanomas. In view of potential clinical use for these compounds, DFB and CFN were selected as examples of BPUs and tested for effects on hematopoiesis in C57Bl/6 mice housed in a conventional environment. DFB and CFN exhibit anti-tumor activity in mice, cause little or no morbidity and mortality and rather than causing bone marrow suppression, which is usual for anti-cancer drugs, these agents stimulate hematopoiesis in vivo and in vitro. Stimulation in vivo was evidenced by increased (up to 112%) peripheral blood granulocytes 6 days after a single injection and enhanced granulopoiesis (approximately 25%) in bone marrow up to 18 days after treatment. That effects of DFB and CFN were on hematopoietic stem cells were indicated by 47% and 48%, respectively, increases in numbers of CFUs and 97% and 95%, respectively, increases in CFUgm. Further, bone marrow cells treated in vitro contained about twice the number of CFUs and CFUgm as control bone marrow cells. Almost all of the increase in number of spleen colonies, whether derived from donors treated in vivo or bone marrow cells treated in vitro, was accounted for by a corresponding increase in number of undifferentiated colonies. These data indicate that DFB and CFN treatment enhance numbers of pluripotential stem cells both in vivo and in vitro. The mechanism of enhancement, direct or indirect, remains to be determined.

A phase I study of intravenous bryostatin 1 in patients with advanced cancer

Bryostatin 1 is a novel antitumour agent derived from Bugula neritina of the marine phylum Ectoprocta. Nineteen patients with advanced solid tumours were entered into a phase I study to evaluate the toxicity and biological effects of bryostatin 1. Bryostatin 1 was given as a one hour intravenous infusion at the beginning of each 2 week treatment cycle. A maximum of three treatment cycles were given. Doses were escalated in steps from 5 to 65 micrograms m-2 in successive patient groups. The maximum tolerated dose was 50 micrograms m-2. Myalgia was the dose limiting toxicity and was of WHO grade 3 in all three patients treated at 65 micrograms m-2. Flu-like symptoms were common but were of maximum WHO grade 2. Hypotension, of maximum WHO grade 1, occurred in six patients treated at doses up to and including 20 micrograms m-2 and may not have been attributable to treatment with bryostatin 1. Cellulitis and thrombophlebitis occurred at the bryostatin 1 infusion site of patients treated at all dose levels up to 50 micrograms m-2, attributable to the 60% ethanol diluent in the bryostatin 1 infusion. Subsequent patients treated at 50 and 65 micrograms m-2 received treatment with an intravenous normal saline flush and they did not develop these complications. Significant decreases of the platelet count and total leucocyte, neutrophil and lymphocyte counts were seen in the first 24 h after treatment at the dose of 65 micrograms m-2. Immediate decreases in haemoglobin of up to 1.9g dl-1 were also noted in patients treated with 65 micrograms m-2, in the absence of clinical evidence of bleeding or haemodynamic compromise. No effect was observed on the incidence of haemopoietic progenitor cells in the marrow. Some patients' neutrophils demonstrated enhanced superoxide radical formation in response to in vitro stimulation with opsonised zymosan (a bacterial polysaccharide) but in the absence of this additional stimulus, no bryostatin 1 effect was observed. Lymphocyte natural killing activity was decreased 2 h after treatment with bryostatin 1, but the effect was not consistently seen 24 h or 7 days later. With the dose schedule examined no antitumour effects were observed. We recommend that bryostatin 1 is used at a dose of 35 to 50 micrograms m-2 two weekly in phase II studies in patients with malignancies including lymphoma, leukaemia, melanoma or hypernephroma, for which pre-clinical investigations suggest antitumour activity.

Chemotherapeutic treatment of recurrent and/or metastatic nasopharyngeal carcinoma: a retrospective analysis of 40 cases

Authors carried out a review of 40 cases of recurrent and/or metastatic nasopharyngeal carcinoma (NPC) treated with cisplatin-based chemotherapy at the Division of Othorhinolaryngology and the Service of Chemotherapy of the University of Palermo between July 1984 and July 1992. All patients were treated with regimens comprising high dose cisplatin (80-100 mg m-2). Histologically there were 29 squamous cell and 11 undifferentiated NPC. Thirty-nine patients were evaluable for response and toxicity. The overall response rate was 64%, with a 20.5% complete response rate and a 43.5% partial response rate. The mean duration of complete responses was 10.2+months, while that of partial responses was 8.6+months. The mean survival of the whole group was 11.4+months, with four patients alive after 2 years of follow-up. No statistically significant difference in response rate and survival was found between patients with metastatic disease and those with locoregional recurrency, and between patients with squamous cell NPC and those with undifferentiated histology. The employed regimens have been generally well tolerated. These data confirm that NPC is a neoplasm highly responsive to chemotherapy. However, duration of objective response and survival are still largely unsatisfactory.

Epirubicin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in cancer chemotherapy

Epirubicin is the 4' epimer of the anthracycline antibiotic doxorubicin, and has been used alone or in combination with other cytotoxic agents in the treatment of a variety of malignancies. Comparative and noncomparative clinical trials have demonstrated that regimens containing conventional doses of epirubicin achieved equivalent objective response rates and overall median survival as similar doxorubicin-containing regimens in the treatment of advanced and early breast cancer, non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), non-Hodgkin's lymphoma, ovarian cancer, gastric cancer and nonresectable primary hepatocellular carcinoma. Recently, dose-intensive regimens of epirubicin have achieved high response rates in a number of malignancies including early and advanced breast cancer and lung cancer. The major acute dose-limiting toxicity of anthracyclines is myelosuppression. In vitro and clinical studies have shown that, at equimolar doses, epirubicin is less myelotoxic than doxorubicin. The lower haematological toxicity of epirubicin, as well as the recent introduction of supportive measures such as colony-stimulating factors, has allowed dose-intensification of epirubicin-containing regimens, which is particularly significant because of the definite dose-response relationship of anthracyclines. Cardiotoxicity, which is manifested clinically as irreversible congestive heart failure and/or cardiomyopathy, is the most important chronic cumulative dose-limiting toxicity of anthracyclines. Epirubicin has a lower propensity to produce cardiotoxic effects than doxorubicin, and its recommended maximum cumulative dose is almost double that of doxorubicin, thus allowing for more treatment cycles and/or higher doses of epirubicin. In summary, dose-intensive epirubicin-containing regimens, which are feasible due to its lower myelosuppression and cardiotoxicity, have produced high response rates in early breast cancer, a potentially curable malignancy, as well as advanced breast, and lung cancers. Furthermore, there is evidence to suggest that improved response rates can improve quality of life in some clinical settings, but whether this leads to prolonged survival has not yet been determined. Recently implemented supportive measures such as colony-stimulating factors, prophylactic antimicrobials and peripheral blood stem cell support may help achieve other potential advantages of dose-intensive epirubicin-containing regimens such as reductions in morbidity and length of hospital admissions.

Differentiation and growth modulation of myeloid leukemia cells by the protein kinase C activating agent bryostatin-1

Bryostatin-1 (Bryo), a macrocyclic lactone of the sea water bryozoan Bugula neritina, is a potent activator of protein kinase C and was found to exhibit antineoplastic activity in several systems. We studied the effect of Bryo on differentiation and growth modulation of human myeloid leukemia cell lines and freshly explanted blood cells from patients with myeloid leukemia. Alterations at the molecular level and phenotypic changes triggered by Bryo were similar, but not identical, to those induced by phorbol esters. Bryo was able to inhibit cellular proliferation as evidenced by [3H]-thymidine uptake and induced morphological changes associated with monocytic differentiation. In studies using continuous cell lines, the glucocorticoid dexamethasone was unable to prevent the Bryo-induced growth inhibition or the induced phenotypic changes. However, in fresh myeloid blood cells dexamethasone attenuated these Bryo-triggered effects. Our own data taken together with reports from the literature reviewed here suggest the following conclusions: (i) Bryo, while lacking tumor promoting activity, is able to induce differentiation in maturation arrested leukemia cells; (ii) it exhibits selective antiproliferative properties in normal or malignant hematopoietic cells and supports growth of multipotent stem cells. These features might qualify Bryostatin-1 as a potential candidate for promising research and possibly for future clinical applications.

Myelodysplastic syndromes: immunohistochemical and morphometric evaluation of proliferative activity in erythropoiesis and endoreduplicative capacity of megakaryocytes

An immunohistochemical and morphometric analysis was performed on bone marrow trephine biopsies in 40 patients with primary myelodysplastic syndromes (MDS) to evaluate the proliferative activity in erythropoiesis and the endoreduplicative capacity of megakaryocytes. Control groups included normal bone marrow and marrow from cases presenting with pernicious anaemia. Double-immunostaining was applied with a monoclonal antibody (PC10) directed against proliferating cell nuclear antigen (PCNA), followed by antibodies against glycophorin C (Ret40f) or platelet glycoprotein IIIa (Y2/51-CD61) for the identification of the erythroid and megakaryocytic cell lineage. Comparison with normal bone marrow showed a reduction of erythropoiesis accompanied by an increase in atypical (micro-) megakaryocytes. Erythroid precursors displayed significant enhancement of PCNA-immunostaining. Megakaryocytes showed no increase in the relative frequency of PC10-positive cells (PCNA-labelling index). In pernicious anaemia, predominance of macrocytic-megaloblastoid erythropoiesis was associated with a striking increase in PCNA-labelling. Cell kinetic studies in this disorder revealed an abnormal arrest, particularly in S-phase which generates an over-expression of PCNA. Similar conditions were believed to be present in MDS with secondary folate deficiency. This mechanism explains the relatively high rate of positively-reacting pro- and erythroblasts which is not invariably accompanied by an increase in cell proliferation. Determination of megakaryocyte size and PCNA-staining capacity resulted in a significant increase in PC10-positive cells among micromegakaryocytes. Our findings on this cell lineage are in keeping with the assumption of a block in endoreduplicative activity at higher ploidy levels, associated with an apparently not-deregulated endomitosis in small-sized megakaryocytes of lower ploidy stages.

Oral tegafur in the treatment of metastatic breast cancer: a phase II study

Between February 1985 and October 1989, 26 patients previously treated for metastatic breast cancer received oral tegafur, at a median daily dose of 1200 mg. Of these, 21 were evaluable for response. The overall response rate was 29%; six (two in lungs, two in skin and two in lymph nodes) of 44 evaluable lesions (14%) responded to therapy. Haematological toxicity was mild, and no other dose-limiting toxicity was seen. The data indicate some activity in heavily pretreated metastatic breast cancer even after previous 5-FU therapy.

Weekly 5-fluorouracil and folinic acid plus escalating doses of cisplatin with glutathione protection in patients with advanced head and neck cancer

Twenty-two patients with advanced head and neck carcinoma were treated with 5FU 400 mg-2 m-1 week and folinic acid 500 mg m-2 week-1 plus CDDP in escalating doses from 20 to 40 mg m-2 week-1 without forced diuresis. Reduced glutathione at the dose of 1.5 g m-2 was employed to protect patients from CDDP-related nephrotoxicity. The aims of the study were: a) to evaluate the therapeutic efficacy of this schedule, and b) to evaluate reduced glutathione as uroprotector. Out of 20 evaluable patients 14 (70%) had a major objective response. A CR with a mean duration of 9.0+ months was achieved in 15% of the patients, a PR of 5.8+ months in 55% of the patients, while 3 patients had stable disease and 4 progressed. It was possible to escalate CDDP up to 35 mg m-2 week-1, but at the dose of CDDP 40 mg m-2 week-1 the occurrence of grade 2 renal toxicity provoked a severe reduction of dose-intensity. Overall, this treatment has been very well tolerated by most patients with few cases of grade 3 gastrointestinal or hematological toxicity. In conclusion, the schedule seems effective and may be safely given to patients with advanced head and neck cancer on outpatient basis. Reduced glutathione seems to be able to reduce, at least partially, CDDP-related nephrotoxicity permitting the delivery of higher CDDP doses.

Biologic Relevance of Elevated Red Cell Adenosine Deaminase Activity in Myelodysplastic Syndromes and Paroxysmal Nocturnal Hemoglobinuria

Red cell adenosine deaminase (ADA-RBC) activity in patients with myelodysplastic syndromes and paroxysmal nocturnal hemoglobinuria is significantly increased compared to that observed in normal controls. ADA-RBC activity is not related to fetal hemoglobin concentration, but it is significantly correlated with hemoglobin concentration at diagnosis and with the degree of morphologic dysplasia in the erythroid lineage. The results of our study suggest that the observed enzymatic abnormality may constitute a non-specific manifestation of the stem cell alteration that determines these disorders.

Macrophages (phagocytic-histiocytic reticular cells) in reactive-inflammatory lesions of the bone marrow and in myelodysplastic syndromes (MDS). An immunohistochemical and morphometric study by use of a new monoclonal antibody (PG-M1)

An immunohistochemical and morphometric study was performed on trephine biopsies of the bone marrow in 52 patients (28 males/24 females; age 68 years) with various subtypes of myelodysplastic syndromes (MDS) to determine the number of macrophages (phagocytic-histiocytic reticular cells). Quantifications included the haemosiderin-storing subpopulation (Prussian-blue reaction) of this lineage as well as the iron-free compartment. The latter was identified by a new monoclonal antibody (PG-M1) which is specifically directed against histiocytic reticular cells. Bone marrow specimens of individuals without haematological disorders and those showing reactive lesions served as controls. In comparison with the normal bone marrow and inflammatory changes (i.e. rheumatoid arthritis) 23 of the 52 patients with MDS revealed a significant increase in macrophages. This increase encompassed not only the iron-laden subpopulation but also the total number of phagocytic reticular cells. Accumulation of macrophages in MDS was speculated to be due to a premature and enforced degradation of dysplastic cell elements leading to phagocytosis of haemosiderin and debris material. Moreover, cells of the monocyte-macrophage system could be involved in the complex pathomechanism of fibrillogenesis, since in a considerable percentage of patients with MDS, an increase in reticulin (argyrophilic) fibres was noticeable. Our finding of an expansion of the macrophage compartment in about half of the patients with MDS is in keeping with results of cell culture studies on colony formation of granulocyte-macrophage precursors (CFU-GM).

Effects of bryostatin 1 and rGM-CSF on the metabolism of 1-beta-D-arabinofuranosylcytosine in human leukaemic myeloblasts

The effects of the protein kinase C activator bryostatin 1, either with or without recombinant granulocyte-macrophage colony stimulating factor (rGM-CSF) were examined with respect to the in vitro metabolism of ara-C in leukaemic myeloblasts obtained from 10 patients with acute myelogenous leukaemia (AML). Coincubation of cells with 12.5 x 10(-9) M bryostatin 1 and 10(-5) M ara-C for 4 h resulted in a significant increase in ara-CTP formation (compared to controls) in 6/10 specimens (mean increase 106%; range 38-255%), and no change in the remainder. In contrast, coincubation of cells with 1.25 ng/ml rGM-CSF resulted in a significant increase in only one specimen, and decreases in two. Bryostatin 1 also significantly increased ara-C DNA incorporation in 6/9 evaluable samples, including two which did not display an increase in ara-CTP formation. Coincubation of cells with both bryostatin 1 and rGM-CSF did not lead to a further increase in ara-CTP formation or ara-C DNA incorporation compared to values obtained with either agent alone. Finally, exposure of blasts to bryostatin 1 for 24 h before ara-C led to an increase in ara-CTP formation in 3/8 additional specimens, and a decrease in one sample displaying evidence of bryostatin 1-induced macrophage differentiation. Incubation of cells with both rGM-CSF and bryostatin 1 for this period resulted in ara-CTP levels equivalent to those obtained with bryostatin 1 alone. These studies indicate that while bryostatin 1 exerts a heterogeneous effect on ara-C metabolism in leukaemic myeloblasts, it is capable of potentiating ara-C phosphorylation in a subset of patient samples, including some that do not exhibit an increase in response to rGM-CSF. They also raise the possibility that bryostatin 1-induced potentiation of ara-C metabolism in some leukaemic cells may contribute, at least in part, to the antileukaemic efficacy of this drug combination.

Activated protein kinase C directly phosphorylates the CD34 antigen in acute lymphoblastic leukemia cells

The precursors of all blood cell lineages are contained within the 1-3% of bone marrow cells which express the CD34 antigen, and this population can reconstitute the hematopoietic system of lethally irradiated animals and humans. A potential regulatory role for the CD34 antigen in progenitor cell function and differentiation was indicated by our recent findings that the CD34 antigen can be phosphorylated in vivo to high stoichiometry in primitive CD34+ cell-lines by activated protein kinase C. To exclude the possibility that these effects were restricted to cell-lines, we have performed similar experiments on fresh cells from a patient with drug-resistant acute lymphoblastic leukemia. Similar to our previous findings, we found the CD34 antigen to be hyperphosphorylated in lymphoblasts labeled in the presence of active phorbols. The same peptides which were hyperphosphorylated in phorbol-stimulated cell-lines were also phosphorylated in phorbol-stimulated lymphoblasts. These data indicate that CD34 is a substrate molecule for PKC in fresh CD34+ lymphoblasts and underline the role of modulators of PKC activity in the biology of primitive leucocytes.

The expression and possible roles of protein kinase C in haematopoietic cells

Protein kinase C (PKC) activation and/or modulation of its isoenzyme expression play key roles in regulating the response of haematopoietic cells to both growth factors and non-physiological inducers of cell growth and differentiation. The level of PKC activities for both cytosol and particulate fractions of ALL and CLL cells are lower than those of AML type. Atypical AML blasts expressing T-cell associated CD2 and CD7 determinants have significantly lower PKC activities compared to typical AML blasts. Analyses of PKC isoforms (-alpha, -beta, and -gamma) show considerable variation with respect to leukaemic cell distributions and subcellular localisations. PKC-alpha and -beta are usually the major species in cytosolic fractions, whereas PKC-gamma is the predominant type in particulate fractions. All lymphoid cells express PKC-gamma in the cytosol, albeit as a minor component, while the occurrence of cytosol PKC-gamma in AML cells appears to be associated in particular with a typical lymphoid antigen expression.