Vistusertib (dual m-TORC1/2 inhibitor) in combination with paclitaxel in patients with high-grade serous ovarian and squamous non-small-cell lung cancer.

Background: We have previously shown that raised p-S6K levels correlate with resistance to chemotherapy in ovarian cancer. We hypothesised that inhibiting p-S6K signalling with the dual m-TORC1/2 inhibitor in patients receiving weekly paclitaxel could improve outcomes in such patients. Patients and methods: In dose escalation, weekly paclitaxel (80 mg/m2) was given 6/7 weeks in combination with two intermittent schedules of vistusertib (dosing starting on the day of paclitaxel): schedule A, vistusertib dosed bd for 3 consecutive days per week (3/7 days) and schedule B, vistusertib dosed bd for 2 consecutive days per week (2/7 days). After establishing a recommended phase II dose (RP2D), expansion cohorts in high-grade serous ovarian cancer (HGSOC) and squamous non-small-cell lung cancer (sqNSCLC) were explored in 25 and 40 patients, respectively. Results: The dose-escalation arms comprised 22 patients with advanced solid tumours. The dose-limiting toxicities were fatigue and mucositis in schedule A and rash in schedule B. On the basis of toxicity and pharmacokinetic (PK) and pharmacodynamic (PD) evaluations, the RP2D was established as 80 mg/m2 paclitaxel with 50 mg vistusertib bd 3/7 days for 6/7 weeks. In the HGSOC expansion, RECIST and GCIG CA125 response rates were 13/25 (52%) and 16/25 (64%), respectively, with median progression-free survival (mPFS) of 5.8 months (95% CI: 3.28-18.54). The RP2D was not well tolerated in the SqNSCLC expansion, but toxicities were manageable after the daily vistusertib dose was reduced to 25 mg bd for the following 23 patients. The RECIST response rate in this group was 8/23 (35%), and the mPFS was 5.8 months (95% CI: 2.76-21.25). Discussion: In this phase I trial, we report a highly active and well-tolerated combination of vistusertib, administered as an intermittent schedule with weekly paclitaxel, in patients with HGSOC and SqNSCLC. Clinical trial registration: ClinicialTrials.gov identifier: CNCT02193633.

[Strategies to Overcome Acquired Resistance to EGFR-TKI Therapy Based on T790M Specific Substances using Osimertinib as an Example]. / Strategien zur Überwindung der erworbenen EGFR-TKI-Resistenz durch T790M spezifische Substanzen am Beispiel von Osimertinib.

Tyrosine kinase inhibitors (TKIs) of the epidermal growth factor receptor (EGFR) are widely used in non-small cell lung cancer patients harboring activating EGFR mutations. However, resistance mechanisms, particularly the T790 M mutation, hamper longer-term therapeutic success of first and second generation EGFR-TKIs. To address this unmet medical need, EGFR-TKIs of the third generation are under clinical development. Relevant clinical efficacy with mainly mild to moderate class-specific side effects has been shown for third-generation EGFR-TKIs. Molecular testing is of major importance in deciding for treatment with third generation EGFR-TKIs. This article elucidates the developmental state of third generation EGFR-TKIs with its focus on Osimertinib, the first and currently the only compound in this class which is approved in Germany. Additionally, the medical importance of molecular diagnosis using tumor tissue and circulating tumor DNA is discussed.

Preference for subcutaneous or intravenous administration of rituximab among patients with untreated CD20+ diffuse large B-cell lymphoma or follicular lymphoma: results from a prospective, randomized, open-label, crossover study (PrefMab).

Background: The aim of this study was to evaluate patient preference and satisfaction for the subcutaneous (s.c.) versus intravenous (i.v.) formulation of rituximab given with chemotherapy in previously untreated patients with CD20+ diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma (FL). Patients and methods: Patients received eight cycles of rituximab according to 2 schedules: Arm A received 1 cycle rituximab i.v. (375 mg/m2) and 3 cycles rituximab s.c. (1400 mg) then 4 cycles rituximab i.v.; Arm B received 4 cycles rituximab i.v. (375 mg/m2) then 4 cycles rituximab s.c. (1400 mg). Alongside rituximab, both arms received 6-8 cycles of chemotherapy (cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP), cyclophosphamide, vincristine, prednisone (CVP), or bendamustine as per standard local practice). Preference for s.c. or i.v. administration was evaluated using the Patient Preference Questionnaire (PPQ) at cycles 6 and 8. Patient satisfaction and convenience were assessed using the Cancer Therapy Satisfaction Questionnaire (CTSQ), and Rituximab Administration Satisfaction Questionnaire (RASQ) at cycles 4 and 8. Results: At the primary data cut-off (19 January 2015), the intent-to-treat population comprised 743 patients. The majority had DLBCL (63%) and baseline characteristics were balanced between arms. At cycle 8, 81% of patients completing the PPQ preferred rituximab s.c. Preference was not impacted by treatment sequence or disease type. Patient satisfaction as measured by RASQ was higher for s.c. versus i.v. CTSQ scores were similar between arms. Adverse events were generally balanced between administration routes and no new safety signals were detected. Conclusion: Most previously untreated patients with CD20+ DLBCL or FL preferred s.c. to i.v. rituximab administration. Patient satisfaction with rituximab treatment was generally greater with s.c. administration. Registered clinical trial number: NCT01724021 (ClinicalTrials.gov).

Survival benefit with erlotinib maintenance therapy in patients with advanced non-small-cell lung cancer (NSCLC) according to response to first-line chemotherapy.

BACKGROUND: In the placebo-controlled phase III SATURN study, maintenance erlotinib after first-line chemotherapy demonstrated significantly prolonged progression-free survival (PFS) and overall survival (OS) in the overall study population of patients with advanced non-small-cell lung cancer (NSCLC). METHODS: After four cycles of platinum-based doublet chemotherapy, patients without progressive disease (PD) were randomised to erlotinib (150 mg/day) or placebo until PD or unacceptable toxicity. In this pre-planned analysis, data are assessed according to response to first-line chemotherapy (complete/partial response [CR/PR] or stable disease [SD]). RESULTS: Following first-line chemotherapy, 889 non-PD patients were included in the intention-to-treat population (55% SD; 44% CR/PR; <1% unknown response). Erlotinib maintenance therapy significantly prolonged PFS in both the SD (hazard ratio [HR] = 0.68; P < 0.0001) and CR/PR (HR = 0.74; P = 0.0059) groups, while OS was significantly prolonged in the SD group only (HR = 0.72; P = 0.0019). The erlotinib-related OS benefit in the SD group remained significant across subgroups, irrespective of tumour histology and/or EGFR mutation status. The incidence of adverse events was similar in the SD group and the overall population, and erlotinib treatment did not negatively impact quality of life. CONCLUSIONS: Patients with advanced NSCLC and SD following first-line platinum-based doublet chemotherapy derive a significant OS benefit from maintenance erlotinib therapy.

Randomised phase II trial of gemcitabine plus vinorelbine vs gemcitabine plus cisplatin vs gemcitabine plus capecitabine in patients with pretreated metastatic breast cancer.

BACKGROUND: An increasing proportion of patients are exposed to anthracyclines and/or taxanes in the adjuvant or neoadjuvant setting. Re-exposure in the metastatic stage is limited by drug resistance, thus evaluation of non-cross-resistant regimens is mandatory. METHODS: Anthracycline-pretreated patients were randomly assigned to three gemcitabine-based regimens. Chemotherapy consisted of gemcitabine 1.000 mg m(-2) plus vinorelbin 25 mg m(-2) on days 1+8 (GemVin), or plus cisplatin 30 mg m(-2) on days 1+8 (GemCis), or plus capecitabine 650 mg m(-2) b.i.d. orally days 1-14 (GemCap), q3w. The primary end point was response rate. RESULTS: A total of 141 patients were recruited on the trial. The overall response rates were 39.0% (GemVin), 47.7% (GemCis) and 34.7% (GemCap). Median progression-free survival was estimated with 5.7, 6.9 and 8.3 months, respectively. Corresponding median survival times were 17.5 (GemVin), 13.0 (GemCis) and 19.4 months (GemCap). Neutropenia ≥grade 3 occurred in 16.7% (Gem/Vin), 4.4% (GemCis) and 0% (Gem/Cap), whereas non-haematological toxicities were rarely severe except grade 3 hand-foot syndrome in 2.0% of the GemCap patients (per patient analysis). CONCLUSIONS: This randomised phase II trial has revealed comparable results for three gemcitabine-based regimens regarding treatment efficacy and toxicity. Gemcitabine-based chemotherapy appears to be a worthwhile treatment option for pretreated patients with metastatic breast cancer.

Erlotinib in routine clinical practice for first-line maintenance therapy in patients with advanced non-small cell lung cancer (NSCLC).

PURPOSE: The controlled phase III trial SATURN demonstrated that maintenance therapy with erlotinib after the first-line platinum-based chemotherapy prolonged progression-free survival (PFS) and overall survival (OS) of non-small cell lung cancer (NSCLC) patients with advanced, non-progressive disease. We conducted the non-interventional study SATURN NIS to investigate the effectiveness and tolerability of erlotinib maintenance in daily clinical practice. METHODS: This single-arm NIS screened 290 patients with locally advanced or metastatic NSCLC (stage IIIB or IV) and stable disease after standard platinum-based first-line chemotherapy in 95 institutions across Germany. Erlotinib was dosed and administered corresponding to the terms of the marketing authorization at the time of recruitment. The main effectiveness endpoint was subjects' OS at 1 year. Subgroup analyses of survival estimates of OS and PFS were performed. RESULTS: 272 patients were eligible for analysis (median age 66 years, 37.1% females, 99.6% Caucasian, median ECOG performance status 1, 61.8% adenocarcinoma, 96.3% of patients with stable disease). Maintenance therapy with erlotinib resulted in median OS comparable to that of the SATURN phase III trial 10.4 months [95% CI: (8.8; 12.5) vs. 11.9 months]. The 1-year survival rate was 45.6% [95% CI: (37.5%; 53.6%)]. No new safety signals were observed. As expected, patients with epidermal growth factor receptor (EGFR) mutations derived a greater benefit concerning OS and PFS than EGFR-wild-type patients. Moreover, a significant association of OS and PFS and the smoking status was observed. CONCLUSIONS: The results of this non-interventional study support the current clinical practice of erlotinib switch maintenance in EGFR-mutation-positive patients.

Pegfilgrastim supports delivery of FEC-100 chemotherapy in elderly patients with high risk breast cancer: a randomized phase 2 trial.

This randomized phase 2 study explored the feasibility of delivering four to six cycles of the dose-intensified regimen FEC-100 (5-fluorouracil, epirubicin, and cyclophosphamide) to elderly patients with stage II-III breast cancer, using pegfilgrastim for neutrophil support. Sixty patients aged 65-77 years received single 6mg doses of pegfilgrastim on day 2 of FEC-100, either as primary prophylaxis (all cycles: PP), or as secondary prophylaxis (all cycles following a neutropenic event: SP). Neutropenic events (a composite endpoint that included grade 3 neutropenia+fever, grade 4 neutropenia, infectious complication requiring systemic anti-infectives and chemotherapy dose delay/reduction) occurred in 24/30 (80%) of the PP and 21/29 (72%) of the SP group in the first cycle. Most patients received all chemotherapy cycles at full dose on schedule (26/30 [87%] PP; 20/29 [69%] SP). These data indicate that delivery of FEC-100 is feasible with pegfilgrastim support in elderly breast cancer patients.

Tumor necrosis factor alpha and CD40 ligand antagonize the inhibitory effects of interleukin 10 on T-cell stimulatory capacity of dendritic cells.

Interleukin (IL)-10 secretion by tumor cells was demonstrated to be one of the mechanisms by which tumor cells can escape immunological recognition and destruction. In dendritic cells (DCs), which are currently used for vaccination therapies for malignant diseases, IL-10 inhibits IL-12 production and induces a state of antigen-specific anergy in CD4- and CD8-positive T cells. We therefore analyzed the effects of different activation stimuli including lipopolysaccharide (LPS), tumor necrosis factor (TNF)-alpha, and CD40 ligation on IL-10 mediated inhibition of DC development and stimulatory capacity. In our study, the addition of IL-10 to the cultures containing granulocyte/macrophage-colony stimulating factor and IL-4 with or without LPS completely inhibited the generation of DCs from peripheral blood monocytes. These cells remained CD14 positive and expressed high levels of IL-10 receptor (IL-10R), suggesting that IL-10 mediates its effects by up-regulating the IL-10R. In contrast, the simultaneous incubation of monocytes with IL-10 and TNF-alpha or soluble CD40 ligand (sCD40L) resulted in the generation of CD83-positive DCs, induction of nuclear localized RelB, and inhibition of IL-10R up-regulation. DCs grown in the presence of IL-10 and TNF-alpha or sCD40L elicited efficient CTL responses against viral and tumor-associated peptide antigens, which, however, were reduced as compared with DC cultures generated without IL-10. IL-10 decreased the production of IL-6 and the expression of IL-12 in the presence of TNF-alpha or sCD40L, but it had no effect on IL-15, IL-18, and TNF-alpha secretion. Our results show that TNF-alpha or CD40 ligation can antagonize the IL-10-mediated inhibition on DC function, suggesting that depending on activation stimuli, the presence of IL-10 does not necessarily result in T-cell anergy.

Her-2/neu-derived peptides are tumor-associated antigens expressed by human renal cell and colon carcinoma lines and are recognized by in vitro induced specific cytotoxic T lymphocytes.

The Her-2/neu oncogene encodes a Mr 185,000 transmembrane protein with homology to the epidermal growth factor receptor. It is overexpressed in 30-40% of breast and ovarian cancers, and this overexpression was shown to correlate with aggressiveness of malignancy and poor prognosis. Using tumor-associated lymphocytes isolated from patients with ovarian or breast cancer, several HLA-A2-restricted, Her-2/neu-derived peptides were identified. Further studies revealed that these tumor-associated CTLs can also lyse other tumors, including non-small cell lung and pancreatic cancer cells, suggesting that Her-2/neu epitopes are shared between several distinct types of epithelial tumors. To analyze whether Her-2/neu epitopes are tumor-associated antigens for renal cell carcinoma (RCC) and colon carcinoma, we induced Her-2/neu peptide-specific CTL responses by primary in vitro immunization and used these CTLs to determine the presentation of Her-2/neu epitopes on human tumor lines. Autologous dendritic cells (DCs) generated from peripheral blood monocytes were pulsed with Her-2/neu-derived peptides E75 and GP2 and used as antigen-presenting cells for CTL priming. High CTL activity toward peptide-pulsed targets was obtained after two weekly restimulations. CTLs induced with DCs generated in the presence of TNF-alpha elicited a higher cytotoxic activity when they were stimulated with the cognate peptide than did CTLs induced with DCs grown in granulocyte macrophage colony-stimulating factor and interleukin 4 alone. The cytotoxicity of induced CTLs was antigen specific and HLA-A2 restricted. Furthermore, these CTLs lysed, in a MHC- and antigen-restricted fashion, not only breast cancer cells but also colon carcinoma and RCC cell lines expressing Her-2/neu. The cytotoxic activity against tumor cells was blocked by cold HLA-A2-positive targets pulsed with the cognate peptide in cold target inhibition assay and by anti-HLA-A2 monoclonal Ab. These results suggest that epitopes derived from Her-2/neu protein might be attractive candidates for broadly applicable vaccines and may prove useful for adoptive immunotherapies designed for colon carcinoma or RCC.

The epithelial tumor antigen MUC1 is expressed in hematological malignancies and is recognized by MUC1-specific cytotoxic T-lymphocytes.

The epithelial mucin MUC1 is overexpressed on the cell surface of many epithelial malignancies as well as on some B-cell lymphomas and multiple myelomas. Recently, we identified two HLA-A2-restricted T-cell epitopes derived from the MUC1 protein. To further extend the potential application of these peptides, we analyzed the expression of MUC1 on blast cells from patients with acute myelogenous leukemia (AML; n = 43) and several other hematological malignancies including acute lymphoblastic leukemia (n = 24), chronic lymphocytic leukemia (n = 36), hairy cell leukemia (n = 9), follicular lymphoma (n = 7), and multiple myeloma (n = 12). Using reverse transcription-PCR and MUC1-specific monoclonal antibodies, MUC1 expression was found in 67% of AML samples and 92% of myeloma samples. To analyze the presentation of MUC1 peptides by primary AML blasts, we induced MUC1-specific CTLs in vitro using peptide-pulsed dendritic cells from HLA-A2+ healthy donors as antigen-presenting cells. These CTLs efficiently lysed in an antigen-specific and HLA-A2-restricted manner not only target cells pulsed with the antigenic peptide but also tumor cell lines including multiple myeloma cells and primary AML blasts that constitutively expressed both MUC1 and HLA-A2. The specificity of the CTLs was confirmed in a cold target inhibition assay. Our data demonstrate that MUC1-derived peptides are tumor antigens in AML and several other hematological malignancies that could potentially be used for immunotherapeutic approaches.

Adoptive transfer of tumor cytotoxic macrophages generated in vitro from circulating blood monocytes: a new approach to cancer immunotherapy.

Cells of the macrophage lineage are considered to be of special importance in the defense of the host against tumor development and spread. Immunotherapeutic strategies to stimulate macrophage (MAC) tumor cytotoxicity make use of activating compounds such as gamma-interferon which are given systemically. However, there are several lines of evidence that in malignant disease the generation of cytotoxic effector MACs is impaired. Both defective cell maturation and loss of responsiveness to activation are described. Here, a first clinical phase I trial of adoptive immunotherapy in cancer patients using autologous MACs generated in vitro from blood monocytes (MOs) is reported. Mononuclear cells were isolated by cytapheresis and density centrifugation and cultured in hydrophobic Teflon bags for 7 days with 2% autologous serum and recombinant human gamma-interferon being present for the last 18 h. Cytotoxic MO-derived MACs were then purified by countercurrent elutriation and reinfused into the patient. A total of 72 therapies have been performed with patients being treated i.v. (n = 8) and i.p. (n = 7). In vitro generated MACs proved to be mature as judged by the expression of maturation-associated surface molecules (MAX antigens, CD16, CD51, CD71), were cytotoxic to U937 tumor cells, and were efficient secretory cells. Cell dose escalation was performed in the first patients beginning with 10(8) MACs to finally infuse the total number of cells recovered from one single cycle of isolation and culture. MAC yield varied from 1 to 17 x 10(8) representing 13-79% of MOs initially seeded. Adoptive MAc transfer was well tolerated. Side effects observed were low-grade fever (less than 38.5 degrees C), induction of the coagulation cascade, and abdominal discomfort after i.p. application. The procoagulant activity of MAC autografts was cell dose dependent and demonstrated by detection of circulating fibrin monomers and thrombin-antithrombin complexes. Biological responses observed included elevated serum neopterin levels and the appearance of interleukin-6 in sera and ascitic fluids. Indication of a possible therapeutic effect was only observed in i.p.-treated patients and consisted of disappearance of malignant ascites in 2 of 7 patients.

Sequential administration of interleukin-3 and granulocyte-macrophage colony-stimulating factor following standard-dose combination chemotherapy with etoposide, ifosfamide, and cisplatin.

PURPOSE: To combine the benefits of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on neutrophil recovery and recombinant human interleukin-3 (rhIL-3) on platelet recovery, we applied standard-dose chemotherapy with the combined administration of IL-3 and GM-CSF to investigate their efficacy and toxicity. PATIENTS AND METHODS: Thirty-six patients with advanced malignancies were treated with etoposide (VP16) 500 mg/m2, ifosfamide 4 g/m2, and cisplatin 50 mg/m2 (VIP), followed by the sequential administration of IL-3 (days 1 to 5 subcutaneously [SC]) and GM-CSF (day 6 to 15 SC). Control patients received GM-CSF alone or were treated without hematopoietic growth factors. RESULTS: Subcutaneous IL-3 and GM-CSF treatment was well tolerated; low-grade fever (World Health Organization grade 1 to 2) was the only consistent clinical symptom. Neutrophil recovery documented that the duration of neutropenia less than 0.1 x 10(9)/L or less than 0.5 x 10(9)/L was identical in GM-CSF as well as IL-3 and GM-CSF-treated patients, but was shortened significantly when compared with patients who were treated without cytokines. Overall platelet recovery was not different significantly in the three treatment groups. The biologic activity of IL-3 in this cytokine combination was reflected in a variety of effects, which included an increase in basophil and eosinophil counts and the induction of circulating hematopoietic progenitor cells. CONCLUSION: We conclude that after conventional-dose VIP chemotherapy, a shortened treatment course of IL-3 (5 days) sequentially followed by GM-CSF (10 days) combines the benefits of prolonged single GM-CSF treatment on WBC count recovery in all patients and an accelerated platelet recovery only in some intensively pretreated patients.

Expression of MUC-1 epitopes on normal bone marrow: implications for the detection of micrometastatic tumor cells.

PURPOSE: The expression of the carcinoma-associated mucin MUC-1 is thought to be restricted to epithelial cells and is used for micrometastatic tumor cell detection in patients with solid tumors, including those with breast cancer. Little is known, however, about the expression of MUC-1 epitopes in normal hematopoietic cells. MATERIALS AND METHODS: MUC-1 expression was analyzed by flow cytometry and immunocytology on bone marrow (BM) mononuclear cells and purified CD34+ cells from healthy volunteers, using different anti-MUC-1-specific monoclonal antibodies. In addition, Western blotting of MUC-1 proteins was performed. RESULTS: Surprisingly, 2% to 10% of normal human BM mononuclear cells expressed MUC-1, as defined by the anti-MUC-1 antibodies BM-2 (2E11), BM-7, 12H12, MAM-6, and HMFG-1. In contrast, two antibodies recognizing the BM-8 and the HMFG-2 epitopes of MUC-1 were not detected. MUC-1+ cells from normal BM consisted primarily of erythroblasts and normoblasts. In agreement with this, normal CD34+ cells cultured in vitro to differentiate into the erythroid lineage showed a strong MUC-1 expression on day 7 proerythroblasts. Western blotting of these cells confirmed that the reactive species is the known high molecular weight MUC-1 protein. CONCLUSION: Our data demonstrate that some MUC-1 epitopes are expressed on normal BM cells and particularly on cells of the erythroid lineage. Hence the application of anti-MUC-1 antibodies for disseminated tumor cell detection in BM or peripheral blood progenitor cells may provide false-positive results, and only carefully evaluated anti-MUC-1 antibodies (eg, HMFG-2) might be selected. Furthermore, MUC-1-targeted immunotherapy in cancer patients might be hampered by the suppression of erythropoiesis.

Randomized, controlled, dose-range study of Ro 25-8315 given before and after a high-dose combination chemotherapy regimen in patients with metastatic or recurrent breast cancer patients.

PURPOSE: To evaluate the safety, pharmacokinetics, and efficacy of three different dose levels of pegylated granulocyte colony-stimulating factor (Ro 25-8315) on progenitor cell mobilization and hematologic recovery in cancer patients. PATIENTS AND METHODS: Breast cancer patients (n = 36) were randomly assigned to receive before (part I) and after (part II) chemotherapy either a single-dose injection of Ro 25-8315 (20 microg/kg, n = 9; 60 microg/kg, n = 9; 100 microg/kg, n = 10) or a standard daily dose of filgrastim (part I, 10 microg/kg/d; part II, 5 microg/kg/d) (control group, n = 8). RESULTS: Overall, Ro 25-8315 was well tolerated. In part I, more progenitor cell mobilization was observed with Ro 25-8315 100 microg/kg. The peak of circulating CD34(+) cells was obtained at day +5 in the four groups, and the absolute neutrophil count (ANC) returned to less than 20 x 10(9)/L by day +15. In part II, high levels of circulating CD34(+) cells (> 20 cells/microL) were obtained in all four groups. The chemotherapy-induced neutropenia (< 1 x 10(9)/L) was similar in the four groups. Ro 25-8315 100 microg/kg was more effective than filgrastim in reducing the number of patients with an ANC less than 0.5 x 10(9)/L on day +12 after chemotherapy. CONCLUSION: A single injection of Ro 25-8315 100 microg/kg might be the optimal dose for steady-state peripheral-blood progenitor cell mobilization. A single injection of 20, 60, or 100 microg/kg could be as efficient as daily administration of filgrastim to correct chemotherapy-induced cytopenia. The optimal dose of Ro 25-8315 should be determined according to the planned chemotherapy regimen.

A new look at the role of p53 in leukemia cell sensitivity to chemotherapy.

A gene encoding the p53 val135 mutant, which assumes mutant conformation at 38.5 degrees C and wild-type conformation at 32.5 degrees C, was introduced into p53-deficient K562 myeloid leukemia cells. Forced expression of wild-type, but not mutant, p53 resulted in growth arrest, accumulation of p21 and Bax proteins, and delayed cell death. Wild-type p53 enhanced the cytotoxic effects of some drugs and attenuated those of others. Compared with wild-type p53, mutant p53 induced much stronger sensitization to drug cytotoxicity. This occurred in the absence of effects on cell cycle progression or activation of several p53 target genes. Although both mutant and wild-type p53 induced changes of immunophenotype, no specific pattern of differentiation was associated with enhanced chemosensitivity. Thus, (1) induction of growth arrest and activation of p53 target genes such as p21 and bax are linked to the wild-type conformation of p53; (2) p53 induces immunophenotypic changes of myeloid leukemia cells suggestive of multidirectional differentiation in a conformation-dependent manner; and (3) (so-called) mutant p53 induces chemosensitization in the absence of effects on cell cycle progression, activation of bax, p21, gadd45 and mdm-2, or a specific pattern of differentiation; and (4) chemosensitization mediated by wild-type p53 may be masked by transcription-dependent induction of growth arrest.

Macrophage colony-stimulating factor is required for human monocyte survival and acts as a cofactor for their terminal differentiation to macrophages in vitro.

Functional competence as well as phenotype heterogeneity of macrophages depend on the completion of their maturation pathway. Differentiation of committed myeloid progenitor cells is induced by colony-stimulating factors (CSF), but no consistent data exist on which factor(s) induce the terminal maturation from the circulating blood monocyte to the mature macrophage. In vitro, monocyte to macrophage transformation occurs in the presence of serum and can be followed by the expression of the maturation-associated antigens gp65-MAX.1, gp68-MAX.3, and CD51. We describe that the differentiation-inducing activity in serum cannot be replaced by any of the known and available purified recombinant cytokines. In the absence of serum monocytes die in suspension cultures while surviving as non-differentiating cells when cultured adherent to plastic. In serum-free suspension cultures survival can be significantly improved by the addition of recombinant human macrophage (rhM)-CSF whereas other cytokines do not. At any stage of serum-free adherent culture, monocyte to macrophage differentiation can be induced rapidly by the addition of serum, whereas cytokines (rhM-CSF, recombinant human granulocyte macrophage [rhGM]-CSF, recombinant human granulocyte [rhG]-CSF, recombinant human interleukin [rhIL]-1, rhIL-3, rhIL-4, rhIL-6, tumor necrosis factor [TNF]-alpha, interferon [IFN]-alpha, IFN-gamma) alone or in combination are not effective. Serum-induced maturation, however, was suppressed in the presence of neutralizing anti-M-CSF antibodies. In addition to phenotype analysis, the secretory repertoire of rhM-CSF cultured monocytes was analyzed in comparison to serum cultured monocytes which further characterized them to be immature cells, i.e., low release of maturation-associated products such as alpha-2-macroglobulin, neopterin, fibronectin, and TNF-alpha, but high IL-6 secretion, an attribute of blood monocytes. We conclude that for monocyte survival in vitro the presence of endogenous M-CSF and possibly other autocrine factors elicited by cell adherence are required for the induction of macrophage maturation; however, yet undefined additional factor(s) are necessary. They are present in serum and may act in conjunction with M-CSF but are distinct from all known cytokines. Our in vitro system may be useful in the screening and discovery of these serum factor(s).

Surface phenotype analysis of human monocyte to macrophage maturation.

Cells of the mononuclear phagocyte system arise from circulating blood monocytes. Upon emigration from the vasculature, monocytes differentiate into macrophages, a process that monocytes similarly undergo in vitro. We have established primary cultures from elutriated or adherence-purified blood monocytes and analyzed the antigenic modulation during monocyte to macrophage transformation, which could be followed by the expression of specific antigens and which required as yet unknown inducer signals present in the serum. It is shown that in the absence of serum monocytes only survive in vitro when cultured adherent to plastic but rapidly die in suspension culture. Starting at 0.5%, serum induced maturation dose-dependently, with the optimal concentration being 2 to 5%. Of those antigens not present on monocyte, the low-affinity Fc receptor (CD16), the alpha-chain of the vitronectin receptor (CD51), gp65-MAX.1, and gp68-MAX.3 were expressed only upon serum-induced macrophage differentiation, whereas the transferrin receptor (CD71), MAX.26, and to some degree also gp65-MAX.11 appeared to be independent of maturation and were also found on primary cultures of adherent monocytes under serum-free conditions. In addition, the rapid induction of HLA class II antigens (within 24 hr) was similar with and without serum, as was the continued high-density expression in long-term culture. The monocyte-specific CD14 antigen was down-regulated in the absence of serum but kept its level of expression on differentiated macrophages. In comparison, alveolar and peritoneal macrophages, respectively, differed in their antigenic phenotype: Alveolar macrophages expressed high HLA class II antigens but low CD14, whereas for peritoneal macrophages the opposite was found. Both interferon-gamma and -alpha suppressed macrophage maturation in vitro but had contrary effects on HLA class II and CD16 expression: Interferon-gamma up-regulated the two types of antigens, which, in contrast, were down-regulated by interferon-alpha.

Dendritic cells in cancer vaccines.

Dendritic cells (DC) are recognized as the most potent antigen-presenting cells with the ability to stimulate naive resting T cells and to initiate primary immune responses. Encouraging results in vaccination studies in animal models and the development of protocols to generate sufficient numbers of human DC for clinical application have led to attempts to verify the feasibility and efficacy of this approach in patients in the context of Phase I/II vaccination trials. This review aims to present a concise overview of the current knowledge in DC development and biology and describes the recent data of the first published DC-based vaccination studies. These preliminary trials indicate that immunotherapies utilizing DC-presenting tumor-associated antigens can safely be administered to patients with cancer and induce significant immunologic and clinical responses.

How many myeloid post-progenitor cells have to be transplanted to completely abrogate neutropenia after peripheral blood progenitor cell transplantation? Results of a computer simulation.

Although hematopoietic recovery following high-dose chemotherapy (HD-CT) and peripheral blood progenitor cell (PBPC) transplantation is rapid, there is still a 5- to 7-day period of severe neutropenia which, theoretically, might be abrogated by an additional transplantation of more differentiated myeloid post-progenitor cells (MPPC). However, both the number of MPPC required to abrogate neutropenia as well as the optimum scheduling of MPPC infusions are currently unknown. Therefore, these questions were addressed by applying a computer model of human granulopoiesis. First, model calculations simulating varying levels of chemotherapy dose intensity were performed and compared with typical clinical neutrophil recovery curves. Using this approach, the data for HD-CT without PBPC transplantation could be reproduced by assuming a reduction of stem cells, committed granulopoietic progenitors and proliferating precursors to about 0.001% of normal. PBPC-supported HD-CT was reproduced by increasing the starting values to at least 0.1%, which corresponded to about 1 to 2 x 10(5)/kg transplanted CFU-GM. Interestingly, reproduction of PBPC-supported HD-CT data could be observed for a wide range of starting values (0.1%-10% of normal), thus confirming the clinical observation that hematopoietic recovery after PBPCT cannot be improved by increasing the dose of transplanted cells over a certain threshold. Using the same simulation model, we then studied the effects of an additional MPPC transplantation. The results showed, that at least 5.7 X 10(8) MPPC/kg have to be provided in addition to the normal PBPC graft to avoid neutropenia <100/microL, and that MPPC are best transplanted on days 0 and 6 after HD-CT. Assuming a 100- to 120-fold cellular ex-vivo expansion rate and MPPC representing about 70% of total expanded cells, 5.7 X 10(8) MPPC/kg could be generated starting from 1 to 2 leukapheresis preparations with about 7 to 8 x 10(6) CD34+ PBPC/kg. Considering furthermore, that only a fraction of ex-vivo generated cells will seed and effectively produce neutrophils in-vivo, the required number of MPPC is most likely even higher and, therefore, might be difficult to be achieved clinically. However, the validity of the model results remains to be proven in appropriate clinical studies.