Treatment-free remission following frontline nilotinib in patients with chronic myeloid leukemia in chronic phase: results from the ENESTfreedom study

The single-arm, phase 2 ENESTfreedom trial assessed the potential for treatment-free remission (TFR; i.e., the ability to maintain a molecular response after stopping therapy) following frontline nilotinib treatment. Patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase with MR^4.5 (BCR-ABL1⩽0.0032% on the International Scale (BCR-ABL1^IS)) and ⩾2 years of frontline nilotinib therapy were enrolled. Patients with sustained deep molecular response during the 1-year nilotinib consolidation phase were eligible to stop treatment and enter the TFR phase. Patients with loss of major molecular response (MMR; BCR-ABL1^IS⩽0.1%) during the TFR phase reinitiated nilotinib. In total, 215 patients entered the consolidation phase, of whom 190 entered the TFR phase. The median duration of nilotinib before stopping treatment was 43.5 months. At 48 weeks after stopping nilotinib, 98 patients (51.6% 95% confidence interval, 44.2–58.9%) remained in MMR or better (primary end point). Of the 86 patients who restarted nilotinib in the treatment reinitiation phase after loss of MMR, 98.8% and 88.4%, respectively, regained MMR and MR^4.5 by the data cutoff date. Consistent with prior reports of imatinib-treated patients, musculoskeletal pain-related events were reported in 24.7% of patients in the TFR phase (consolidation phase, 16.3%).

Long-term benefits and risks of frontline nilotinib vs imatinib for chronic myeloid leukemia in chronic phase: 5-year update of the randomized ENESTnd trial

In the phase 3 Evaluating Nilotinib Efficacy and Safety in Clinical Trials–Newly Diagnosed Patients (ENESTnd) study, nilotinib resulted in earlier and higher response rates and a lower risk of progression to accelerated phase/blast crisis (AP/BC) than imatinib in patients with newly diagnosed chronic myeloid leukemia in chronic phase (CML-CP). Here, patients' long-term outcomes in ENESTnd are evaluated after a minimum follow-up of 5 years. By 5 years, more than half of all patients in each nilotinib arm (300 mg twice daily, 54% 400 mg twice daily, 52%) achieved a molecular response 4.5 (MR^4.5; BCR-ABL⩽0.0032% on the International Scale) compared with 31% of patients in the imatinib arm. A benefit of nilotinib was observed across all Sokal risk groups. Overall, safety results remained consistent with those from previous reports. Numerically more cardiovascular events (CVEs) occurred in patients receiving nilotinib vs imatinib, and elevations in blood cholesterol and glucose levels were also more frequent with nilotinib. In contrast to the high mortality rate associated with CML progression, few deaths in any arm were associated with CVEs, infections or pulmonary diseases. These long-term results support the positive benefit-risk profile of frontline nilotinib 300 mg twice daily in patients with CML-CP.

Targeted ED-B fibronectin SPECT in vivo imaging in experimental atherosclerosis

AIM

The extracellular matrix protein ED-B fibronectin (ED-B) is upregulated in inflammatory atherosclerotic lesions. However, functional in vivo imaging of ED-B-containing plaques has not been explored. This study evaluated whether [(99m)Tc]-conjugated AP39 ([(99m)Tc]-AP39), a single-chain antibody specific to ED-B, can be used for in vivo detection of atherosclerotic plaques in Western diet (WD)-fed, apolipoprotein E-deficient (apoE-/-) mice as compared to wildtype (WT) control mice.

METHODS

Using SPECT, 12-month-old WD-fed apoE-/- and WT mice were studied 4 hours after injecting [(99m)Tc]-AP39 (148 MBq). Subsequently, mice were sacrificed, thoracic aortas measured in a g-counter, and plaques analyzed using histology, immuno-histochemistry, autoradiography, and morphometry.

RESULTS

In vivo [(99m)Tc]-AP39-SPECT imaging of apoE-/- mice demonstrated a significant signal activity in the plaque-ridden thoracic aorta (52.236 ± 40.646 cpm/cm³) that co-localized with the aortic arch and the supra-aortic arteries in MRI scans. Low signal activity (9.468 ± 4.976 cpm/cm³) was observed in WT mice. In apoE-/- mice, the strongest signals were detected in the aortic root, aortic arch and along the abdominal aorta. Autoradiography analysis of aortas from apoE-/- mice confirmed the in vivo observation by demonstrating signal localization in atherosclerotic plaques. The size of autoradiography-positive plaque areas correlated significantly with the size of ED-B-positive (r=0.645, P=0.044) or macrophage-infiltrated (r=0.84, P<0.002) plaques. A significant correlation was found between the sizes of ED-B-positive and macrophage-infiltrated plaque areas (r=0.93, P<0.01).

CONCLUSION

[(99m)Tc]-AP39-SPECT in vivo imaging detects inflammatory plaque lesions in WD-fed apoE-/- mice.

Phase I/II study of the tumor-targeting human L19-IL2 monoclonal antibody-cytokine fusion protein in combination with DTIC in metastatic melanoma patients

9064

Background:L19-IL2 is a tumor targeted immunocytokine constituted by a single chain Fragment variable (scFv) format directed against the ED-B domain of fibronectin and the human cytokine interleukin-2 (IL2). The recommended dose (RD) for monotherapy of advanced solid cancer patients was established to be 22.5 Mio IU IL2 equivalent on day 1, 3, and 5 of a 21-day cycle. Here we report clinical results of the dose escalation part of a phase I/II study assessing L19-IL2 in combination with DTIC chemotherapy in metastatic melanoma patients. Methods: L19-IL2 was administered as an i.v. infusion at doses of 10 (n=3), 15 (n=3) and 22.5 MioIU IL2 equivalent dose (n=4) on days 1, 3 and 5 every 21 days in combination with DTIC 1000 mg/m2 on Day 1 for up to 6 treatment cycles. Serum samples for PK evaluation and induction of human antifusion antibodies to L19 (HAFA) were collected. Flow cytometry (T and NK/B cell panels) was performed. Data on safety and activity were evaluated using CTC v3.0 and RECIST criteria, respectively. Results: All 10 patients had progressive metastatic melanoma and the majority had already received prior systemic therapy. Median age at start of treatment was 62 years (52–74). There were no treatment related deaths and the treatment was well tolerated, details of CTC evaluation will be presented. The dose of 22.5 Mio IU day 1, 3, and 5 in combination with 1000 mg DTIC/m2 on day 1, repeated on day 22 was defined as the RD for up to 6 treatment cycles. 10 patients were evaluable for response. We observed 1 partial remission at the 15 Mio IL2 dose level after 4 treatment cycles. Immunophenotyping analysis showed transient stimulation of NK cells, T4 cells, and CTLs. Pharmacokinetic data will be presented. Conclusions: L19-IL2 at a dose of 22.5 Mio IU IL2 equivalent on days 1, 3, and 5 of a 3-weekly schedule can be safely combined with standard DTIC in metastatic melanoma patients. Toxicity was manageable and reversible. Preliminary evaluation suggests clinical activity of the L19IL2/DTIC regimen in metastatic melanoma patients.

[Table: see text]

Wilms' tumour gene 1 (WT1) in human neoplasia

The transcription factor Wilms' tumour gene 1 (WT1) is important as a prognostic marker as well as in the detection and monitoring of minimal residual disease in leukaemia and myelodysplastic syndromes. Evidence has accumulated over the past decade to show that WT1 is a key molecule for tumour proliferation in a large number of human neoplasms most prominent in acute leukaemias, making it a suitable target for therapeutic strategies. Based on animal results, showing safety and efficacy of immunization with WT1 peptides and protein, early clinical trials in leukaemia have recently been initiated. The First International Conference on WT1 in Human Neoplasia was held in Berlin, March 11--12, 2004. This report reviews the current knowledge on the role of WT1 in tumour promotion and as a diagnostic and therapeutic target, and summarizes the data presented and discussed in this meeting.

Quantitative real-time RT-PCR detects elevated Wilms tumor gene (WT1) expression in autologous blood stem cell preparations (PBSCs) from acute myeloid leukemia (AML) patients indicating contamination with leukemic blasts

High-dose chemotherapy with subsequent autologous stem cell transplantation is believed to be of therapeutic benefit in patients with acute myeloid leukemia (AML), especially when no allogeneic bone marrow donor is available. One of the main risks is contamination of the stem cell preparations with leukemic blasts, which may account for a higher relapse rate compared to allogeneic bone marrow transplantation. Since overexpression of WT1 is common in leukemic blasts, we investigated, whether PBSCs from AML patients express WT1 at a higher level as compared to patients with solid cancers. PBSCs of seven patients with AML and of five patients with solid cancers were investigated for WT1 expression. Total WT1 copy count was determined in a standardized quantitative real time RT-PCR. WT1 expression was found in all AML PBSCs with an average copy number of 49.99 +/- 61.09. In solid cancers WT1 expression was statistically significantly lower with a copy number of 3.51 +/- 1.92. In AML patients with sustained complete remission we found a nearly significantly lower WT1 expression than in patients who relapsed within the first year after stem cell transplantation. Our data show a higher WT1 expression in PBSCs of AML patients compared to patients with solid cancers. This finding might indicate a contamination with leukemic blasts. Quantification of WT1 in PBSCs might therefore be useful to estimate the risk of relapse after autologous stem cell transplantation in AML patients.

The use of hirudin as universal anticoagulant in haematology, clinical chemistry and blood grouping

Undesirable interactions between anticoagulants and diagnostic test kit procedures so far have prevented the development of a single uniform blood sampling tube. Contrary to K2-EDTA, heparin and other anticoagulants, hirudin only minimally alters blood cells and dissolved blood constituents, thus qualifying as a universal anticoagulant for diagnostic purposes. Automated complete blood counts, automated analyses of clinical chemistry analytes and immunohaematology were performed from hirudinised and routinely processed blood obtained from healthy volunteers (n=35) and hospitalised patients (n=45). Hirudin (400 ATU/ml blood) sufficiently anticoagulated blood for diagnostic purposes. The measurements of automated complete blood counts obtained from K2-EDTA-anticoagulated and hirudinised blood correlated significantly as did the measurements of 24 clinical chemistry analytes from hirudinised plasma and serum. Regression analysis revealed that the results of complete blood counts and clinical chemistry tests were predictable from the respective measurements from hirudinised blood (p=0.001). Immunohaematological tests and cross-matching from hirudinised and native blood of the same donors gave identical results. Single clotting factors, but not global coagulation analytes, could be measured from hirudinised blood. Therefore, a universal hirudin-containing blood sampling tube could be designed for automated analysis of haematological, serological and clinical chemistry analytes.

Measurement of hematological, clinical chemistry, and infection parameters from hirudinized blood collected in universal blood sampling tubes

Hirudin, the anticoagulatory polypeptide of the leech Hirudo medicinalis, strongly inhibits thrombus formation by specifically interacting with thrombin. For diagnostic purposes, hirudin should be superior to other anticlotting compounds because it only minimally alters the mineral, protein, and cellular blood constituents. To test this hypothesis, hirudinized and routinely processed venous blood from 80 healthy volunteers and patients was subjected to a variety of automated blood tests. A strong correlation was found between the results of automated complete blood counts obtained from K(2)-ethylenediaminetetraacetic acid (EDTA) anticoagulated and hirudinized blood (1000 antithrombin units [ATU] hirudin/ml). In addition, clinical chemistry and serological infection parameters (asparlat amintransferase [ASAT], lactate dehydrogenase [LDH], sodium, and so on, and antibodies against hepatitis B and C and human immunodeficiency virus [HIV]1/2, respectively) correlated well when measured in serum as compared with hirudinized plasma. Contrary to single clotting factors, global coagulation parameters (activated partial thromboplastin time [aPTT], prothrombin time [PT]) could not be measured in hirudinized blood. Recombinant hirudin neither interfered with immunophenotyping of mononuclear cells using FACScan analysis, nor did it alter the detection of Wilms' tumor gene expression by RT-PCR technology even at high doses (5000 ATU hirudin). Thus, a hirudin-containing blood sampling tube can be designed as a universal blood sampling tube (UBT) for testing the majority of diagnostic blood parameters.

Zoledronic acid is superior to pamidronate in the treatment of hypercalcemia of malignancy: a pooled analysis of two randomized, controlled clinical trials

PURPOSE

Two identical, concurrent, parallel, multicenter, randomized, double-blind, double-dummy trials were conducted to compare the efficacy and safety of zoledronic acid and pamidronate for treating hypercalcemia of malignancy (HCM).

PATIENTS AND METHODS

Patients with moderate to severe HCM (corrected serum calcium [CSC] > or = 3.00 mmol/L [12.0 mg/dL]) were treated with a single dose of zoledronic acid (4 or 8 mg) via 5-minute infusion or pamidronate (90 mg) via 2-hour infusion. A protocol-specified pooled analysis of the two parallel trials was performed. Clinical end points included rate of complete response by day 10, response duration, and time to relapse.

RESULTS

Two hundred eighty-seven patients were randomized and evaluated for safety; 275 were evaluated for efficacy. Both doses of zoledronic acid were superior to pamidronate in the treatment of HCM. The complete response rates by day 10 were 88.4% (P = .002), 86.7% (P = .015), and 69.7% for zoledronic acid 4 mg and 8 mg and pamidronate 90 mg, respectively. Normalization of CSC occurred by day 4 in approximately 50% of patients treated with zoledronic acid and in only 33.3% of the pamidronate-treated patients. The median duration of complete response favored zoledronic acid 4 and 8 mg over pamidronate 90 mg with response durations of 32, 43, and 18 days, respectively.

CONCLUSION

Zoledronic acid is superior to pamidronate; 4 mg is the dose recommended for initial treatment of HCM and 8 mg for relapsed or refractory hypercalcemia.

Cyclophosphamide, adriamycin and dexamethasone (CAD) is a highly effective therapy for patients with advanced multiple myeloma

BACKGROUND

Patients with advanced multiple myeloma (stage III or progressive myeloma) received the CAD protocol every three weeks: cyclophosphamide 200 mg/m2 i.v./orally days 1-4, adriamycin 30 mg/m2 i.v. on day 1 and dexamethasone 40 mg p.o. days 1-4.

PATIENTS AND METHODS

Forty-six patients with a median age of sixty years (range 34-84 years) were enrolled. According to Durie-Salmon 44 patients were in stage III, 2 in stage II; 6 patients had renal insufficiency (stage B). Twenty-three patients were pre-treated at least with melphalane/prednisone.

RESULTS

Remission rates were as follows: complete remission 4%, partial remission 70%, minimal change 11%, no change 11%, progressive disease 4%. After an observation time of 14 months the median progression free interval for 33 patients not treated with subsequent high-dose chemotherapy with stem-cell support was more than 14 months. Overall, treatment was well tolerated. After 209 cycles given febrile neutropenia occurred in 11% of cycles including one fatal outcome. Neutropenia or thrombocytopenia grade 3-4 WHO was recorded in 18% and 6% of the cycles, respectively.

CONCLUSIONS

This study shows that CAD is an effective regimen with an overall remission rate of 74%. The CAD protocol should be further evaluated in prospective trials.

Wilms' tumor gene (WT1) expression in lung cancer, colon cancer and glioblastoma cell lines compared to freshly isolated tumor specimens

The Wilms' tumor gene (WT1) encodes a transcriptional regulator involved in growth and differentiation of various tissue types. A continuous over-expression of WT1 was found in leukemic blasts, thus suggesting an oncogenic function. Solid cancer entities have also been described as expressing WT1. We systematically analyzed WT1 expression in small-cell and non-small-cell lung cancer, colon cancer and glioblastoma patients and in the respective tumor cell lines. Using reverse transcription/polymerase chain reaction, we found WT1 expression in glioblastoma (5 of 8), lung (5 of 11), and colon cancer (5 of 15) cell lines. While WT1 was expressed in only 1 of 12 lung cancer and 1 of 5 glioblastoma specimens, it was not detected in colon cancer or macroscopically tumor-free colon and lung tissue. In addition, HT29 colon cancer cells showed a loss of WT1 expression when grown to confluence or induced to differentiate by sodium butyrate. From this evidence, testing for WT1 expression is not clinically relevant for colon cancer, lung cancer, or glioblastoma patients. WT1 expression in cancer cell lines can probably be attributed to optimized in vitro growth conditions.

Analysis of Wilms tumor gene (WT1) expression in acute leukemia patients with special reference to the differential diagnosis between eosinophilic leukemia and idiopathic hypereosinophilic syndromes

Continuous Wilms' tumor gene (WT1) expression is a typical feature of leukemic blasts in AML, ALL, and blast crisis CML patients. It is easily detectable by a variety of RT-PCR protocols, which differ mainly in their sensitivity. The nuclear WT1 protein can be found in blasts of approximately 50-60% of acute leukemia patients at diagnosis. Conversely, WT1 is only transiently expressed in normal hemopoiesis. Early CD34+ hemopoietic progenitors express WT1, whereas no WT1 mRNA transcripts can be found in mature blood cells and differentiation-induced committed CD34- progenitors. As a powerful complementary diagnostic tool, testing for WT1 expression can be helpful to discriminate between eosinophilic leukemia (EoL) patients and patients with idiopathic hypereosinophilic syndromes. Conflicting data about the usefulness of testing for WT1 expression to monitor minimal residual disease (MRD) in treated leukemia patients will be discussed. Finally, research strategies to circumvent shortcomings in detecting leukemia-associated WT1 expression will be outlined.

Primary tracheal leiomyosarcoma

We present the clinical course of a 56-year-old female patient with a primary tracheal leiomyosarcoma. The diagnostic approach and pathological classification of this seldom described tumour remains extremely difficult. We discuss the symptoms as well as the diagnostic and therapeutic procedures, including multimodal chemotherapy with organ-preserving surgery leading to complete remission.

Cryptococcosis in Hodgkin's disease: description of two cases and review of the literature

Systemic mycosis caused by Cryptococcus neoformans frequently becomes life threatening in patients with cellular immunodeficiencies. In contrast to AIDS patients, there are only a few reports of concurrent systemic cryptococcosis in patients with Hodgkin's disease (HD). Only two of 75 (2.7%) patients with HD who were consecutively admitted to our hospital in the past decade developed Cryptococcus neoformans infection. Both had stage IVB (Ann Arbor) HD with bone marrow involvement and absolute lymphopenia (< 1/nl). We have reviewed the literature and analyzed the data of 54 cases with concurrent cryptococcosis and HD. Presence of HD for > or = 12 months, stage IV disease, absolute lymphopenia (< 1/nl), and extensive pretreatment were the most common features among these patients and must be regarded as predisposing for acquiring a cryptococcal infection. In our patients antimycotic therapy was successful using liposomal amphotericin B (lipAmB) simultaneously with cytotoxic therapy for HD. Drug level measurements performed in one patient revealed a higher level of amphotericin B in CSF when the liposomal formulation was administered as compared with the level in CSF after administration of conventional amphotericin B. To our knowledge, this is the first report on antimycotic treatment of cryptococcosis with lipAmB in patients with HD. Regarding the favorable therapeutic index of lipAmB as compared with conventional amphotericin B, the drug should be considered as a less toxic and perhaps more effective alternative in the therapy of acute cryptococcosis, especially when cytotoxic treatment is administered simultaneously.

Distinction of eosinophilic leukaemia from idiopathic hypereosinophilic syndrome by analysis of Wilms' tumour gene expression

In patients presenting with immature eosinophilic precursors it is notoriously difficult to distinguish acute eosinophilic leukaemia (EoL) from the benign idiopathic hypereosinophilic syndrome (HES), based on morphological, cytochemical and immunophenotyping criteria, alone. Cytogenetic analysis or fluorescence in situ hybridization (FISH) can help in discriminating between these rare haematological disorders, but often treatment decisions cannot wait for the results of these time-consuming techniques. Recently, we and others found Wilms' tumour (WT1) gene expression to be increased in virtually all patients with acute leukaemias, whereas normal haemopoietic progenitors express the WT1 gene at much lower levels or not at all. To determine whether detection of WT1 gene expression is useful to distinguish EoL from HES patients, we analysed, by RT-PCR, bone marrow or blood mononuclear cells from EoL (n=3), HES (n=3) and reactive eosinophilia patients (n = 4) for WT1 gene expression. Using our WT1-RT-PCR protocol, we found WT1 gene expression to be restricted to EoL patients. By detecting WT1 mRNA transcripts in the cerebrospinal fluid using RT-PCR, we were also able to diagnose isolated CNS-relapsed leukaemia, initially confused with bacterial meningitis, in an EoL patient. In conclusion, we show that WT1-RT-PCR is a powerful complementary diagnostic tool to distinguish acute eosinophilic leukaemia from the hypereosinophilic syndromes. This observation needs confirmation in a larger series of EoL and HES patients.

Detection by monoclonal antibodies of the Wilms' tumor (WT1) nuclear protein in patients with acute leukemia

The WT1 gene encodes a transcriptional regulator which during embryogenesis is involved in growth control and differentiation of diverse tissues. It is also expressed in few human malignancies, including acute leukemia. We tested 3 different monoclonal antibodies (MAbs H2, H7, HCl7) and the polyvalent serum WTC-19 for WT1 protein detection in mononuclear cell (MNC) preparations of 104 newly diagnosed acute leukemia patients. Using RT-PCR, these MNC preparations were also analyzed for WT1 gene expression. MAbs H2, H7 and HCl7 and the polyclonal WTC-19 exhibited nuclear immunoreactivity in 63 of 99, 28 of 56, 38 of 60 and 22 of 43 WT1 gene-expressing leukemia samples, respectively. With these antibodies, no WT1 immunoreactivity was found in MNCs from blood of healthy volunteers, from CD34+ progenitor cell-enriched leukapheresis products of patients conditioned for peripheral stem cell harvest or from reactive bone marrow. Contrary to WTC-19, all MAbs reacted highly specifically with the WT1 protein (0.71 vs. 1.0). The WT1 protein was heterogeneously detected in leukemia blast preparations by all antibodies, irrespective of cell morphology. Very few HL60 cells and blasts from newly diagnosed leukemia patients interspersed among normal blood MNCs (50 blasts among 5 x 10(5) MNCs) were easy to identify by indirect immunofluorescence using MAbs H2 and HCl7. Taken together, MAbs H2 and HCl7 were superior to MAb H7 and the polyvalent WTC-19 in detecting the WT1 nuclear protein.

Presence of Wilms' tumor gene (wt1) transcripts and the WT1 nuclear protein in the majority of human acute leukemias

The wt1 gene is located on chromosome 11p13 and encodes a zinc finger motif-containing transcription factor involved in regulation of growth and differentiation. Its expression was shown during embryonic development in various tissues as well as in a few human malignancies including acute leukemias. Using RT-PCR, we found wt1 gene expression in blast cells of the majority of 150 acute leukemia patients. Particularly, the wt1 transcript was detected in 12 of 14 (86%) pre-pre-B-ALL patients, in 33 of 41 (80%) cALL patients, in 23 of 31 (74%) T-ALL patients, and in 53 of 57 (93%) AML patients. Additionally, mononuclear cells from CML patients expressed the wt1 gene only when diagnosed with blast crisis. In contrast to acute human leukemias, mononuclear cells from reactive bone marrow (n = 4), and peripheral blood of healthy volunteers (n = 20), as well as normal peripheral CD34+ hematopoietic progenitors (n = 6) did not express the wt1 gene at detectable levels. Using the anti-WT1 MoAb 6F-H2 in an immunofluorescence assay on single cell level, we found the translated WT1 protein only in nuclei of leukemia blast cells but not in nuclei of normal CD34+ hematopoietic progenitor cells. Blast cells of 12 of 20 leukemia patients (60%) all tested positive for the wt1 gene expression by RT-PCR displayed a strong nuclear immunofluorescence. Its expression in the majority of human acute leukemias but not in normal mononuclear blood cells and normal CD34+ hematopoietic progenitors qualifies the wt1 gene transcript as a 'pan-acute leukemic' marker probably useful in monitoring minimal residual disease after chemotherapy and in detecting leukemic blast cells in purged or unpurged hematopoietic stem cell preparations intended to be used for autologous bone marrow transplantation.

Expression of the wt1 Wilms' tumor gene by normal and malignant human melanocytes

We report expression of the wt1 (Wilms' tumor) gene by cultured human melanoma cells. Using RNA polymerase chain reaction analysis, wt1 transcripts were detected in 7 of 9 melanoma cell lines but not in 5 normal melanocyte strains. In Northern blot analysis, steady-state wt1 mRNA levels were found in 2 of 4 melanoma lines but not in normal melanocytes. Sequence analysis of the wt1 cDNA expressed by melanoma cell line WM 902-B revealed the presence of 4 previously published splice variants but no evidence for mutations in the coding region. Previous work has shown that WT1 modulates transcription after binding to the early growth response (EGR)-1 sites present in the platelet-derived growth factor (PDGF)-A chain promoter; the PDGF-A chain gene is known to be expressed by various melanoma cell lines. Based on these findings, we studied the relationship of wt1 and PDGF-A chain gene expression in melanoma cell lines. Co-expression of the wt1 and the PDGF-A chain genes was observed in 2 melanoma cell lines with mutated p53 but not in 2 melanoma cell lines with wild-type p53; this result is consistent with a previous report showing that, in the context of absent or mutated p53, WT1 acts as a transcriptional activator, whereas in the presence of wild-type p53 it acts as a repressor.

Growth regulation of cultured human nevus cells

Cells isolated from congenital melanocytic nevi and cultured in vitro have growth characteristics that resemble their premalignant stage in situ. A serum-free, chemically defined medium has been developed that allows continuous growth of established nevus cultures for up to several months. Like primary melanoma cells, nevus cells in high-calcium-containing W489 medium require insulin for growth. In contrast to melanoma cells, nevus cells in serum-free medium require the presence of alpha-melanocyte-stimulating hormone, which enhanced intracellular levels of cyclic adenosine monophosphate. In contrast to the requirements of normal human melanocytes from newborn foreskin, congenital nevus cells grow with less dependency on basic fibroblast growth factor (bFGF). Nevus cultures contain bFGF-like activity, and they express bFGF mRNA. Nevic cells of compound nevi also express bFGF mRNA in situ but only in the junctional areas. These results indicate that bFGF plays an important growth regulatory role for nevus cells in vitro and in vivo.

Constitutive expression of multiple growth factor genes by melanoma cells but not normal melanocytes

In a panel of metastatic melanoma cell lines we found steady-state mRNA transcripts for multiple growth factors including basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF)-A, PDGF-B, transforming growth factor (TGF)- beta 1, TGF- alpha, melanoma growth-stimulating activity (MGSA), interleukin (IL)-1 alpha, and IL-1 beta but not insulin-like growth factor (IGF)-1 or IGF-2. Expression of growth factor genes was constitutive because prior to RNA extraction melanoma cells were maintained in a chemically defined culture medium free of exogenous growth factors. Each of four cell lines had an individual pattern of expression of either two, four, five, or seven growth factors; however, all cell lines shared expression of the bFGF gene. Two strains of normal melanocytes expressed TGF- beta 1 but not bFGF, PDGF, TGF- alpha , or MGSA mRNA at detectable levels. We tested growth-modulatory effects of the growth factors most frequently expressed by melanoma cells (bFGF, TGF- alpha, TGF- beta, PDGF). None of these stimulated melanoma cell growth consistently, whereas exogenous, acid-activated TGF- beta inhibited melanoma growth at concentrations greater than 10 ng/ml, suggesting that bioactive TGF- beta may represent a physiologic growth inhibitor. Neither neutralizing antisera to PDGF or TGF- alpha nor a monoclonal antibody to the epidermal growth factor (EGF)-receptor inhibited melanoma cell growth. Our results indicate that multiple growth factors are expressed simultaneously and constitutively by melanoma cells but not normal melanocytes in culture. Expression of bFGF is a common feature underscoring the significance of bFGF as an autocrine factor for melanoma cells as described earlier. Secreted PDGF and TGF- alpha are apparently not involved in or not essential for autocrine growth stimulation of melanoma cells.

Tumor progression in the human melanocytic system

The isolation and routine tissue culture of melanocytic cells from normal skin, precursor nevi, primary and metastatic melanomas has allowed the experimental study of different stages of tumor progression. Characteristic differences between cultured normal melanocytes and highly malignant metastatic melanoma cells were: 1) limited life span for normal melanocytes and non-malignant nevus cells versus infinite growth for malignant melanoma cells; 2) inability to grow anchorage-independently versus high colony forming-efficiency in soft agar; 3) non-tumorigenicity versus tumorigenicity in athymic nude mice; 4) dependence on exogenous growth factors and other mitogens versus autonomous growth in protein-free medium; 5) expression of melanocyte-associated antigens versus expression of melanoma-associated antigens; and 6) diploid karyotype versus non-random chromosomal abnormalities. The only major distinction found between advanced primary and metastatic melanomas was that only metastatic melanoma cells proliferated continuously in the absence of growth factors or other proteins. However, advanced primary melanoma cells could be clearly distinguished from dysplastic nevus cells by their growth behavior and growth factor requirements. Only limited information is available on the biologic, genetic, immunologic and molecular properties of dysplastic nevus cells and early (radial growth phase) primary melanoma cells but these cells appear to differ markedly from advanced primary and metastatic cells. The availability of cells from sequential steps of tumor progression in the human melanocytic system offers a unique experimental model for the study of malignant transformation.

Rapid dissociation of adherent human tumor cells by ultrasound

Cultured human melanoma and gastrointestinal carcinoma cells were detached from substrate and further dissociated by placing the culture vessel into a water-filled ultrasonic cleaner (43 kHz) and sonicating it for 10-50 s. Plating efficiency and long-term growth of three melanoma cell lines were similar after ultrasound or trypsin detachment. Binding of monoclonal antibodies that define normal and tumor-associated antigens on melanoma and colorectal carcinoma cells was not affected by ultrasound in 21 out of 23 cases. The 40 kDa colorectal carcinoma-associated antigen defined by monoclonal antibody CO 17-1A was more highly expressed after ultrasonication than trypsinization. The antigen defined by antibody CO 44.1 on these cells was more sensitive to sonication. This method represents a rapid, effective and gentle alternative to trypsin detachment of cultured cells, especially when repeated cell washing or centrifugation steps are required.

Metastatic but not primary melanoma cell lines grow in vitro independently of exogenous growth factors

Five out of 6 cell lines derived from metastatic melanoma lesions grew in a chemically defined base medium consisting of a mixture of calcium-supplemented MCDB 153 and L 15 media in the absence of any polypeptide growth factors. In contrast, under these conditions no growth was seen in any of 5 primary melanoma cell lines tested, including 2 cell lines from patients whose metastatic cells proliferated well in base medium. Growth stimulation of all 11 melanoma cell lines by epidermal growth factor (EGF), transferrin, insulin, and insulin-like growth factor (IGF)-1 alone and in various combinations was studied. Insulin represented the strongest single growth factor for primary and metastatic melanoma cell lines. The metastatic cell lines remained growth-responsive to EGF, insulin and transferrin and responded more vigorously to these exogenously provided mitogens than the primary cell lines. No synergistic or additive growth effects of insulin, transferrin, or EGF for primary and metastatic cell lines were observed. Cross-linking studies with 125I-IGF-1 demonstrate surface expression of the type-I IGF receptor on melanoma cells. Growth stimulation by insulin and IGF-1 was inhibited by adding to the culture medium a monoclonal antibody to the type-I IGF receptor. Our studies indicate that IGF-1 and insulin are major growth factors for melanoma cells and act via the type-I IGF receptor.

A quantitative electron microscopic study of the effect of glucocorticoids in vivo on the early postnatal differentiation of paraneuronal cells in the carotid body and the adrenal medulla of the rat

The postnatal differentiation of carotid body chief cells and endocrine adrenal medullary cells was comparatively examined during ontogenesis and in rats which were treated with dexamethasone for 7 days after birth. Ultrastructure and innervation of carotid body chief cells are mature in neonates according to the functional requirements of chemoreception. By the end of the first postnatal week, only an increase in number of dense core vesicles can be noticed, the concentration of which then will reach the adult level. Under the effect of dexamethasone most of the heterochromatin is transformed into finely dispersed euchromatin within the nuclei of carotid body chief cells. In the cytoplasm, the Golgi apparatus becomes larger and the granular endoplasmic reticulum hypertrophic. The number of catecholamines storing dense core vesicles increases considerably. The innervation density remains constant. In contrast to the carotid body chief cells, the adrenal medullary cells have not reached their definitive maturity at the time of birth. Besides phenotypes of adrenaline-cells, noradrenaline-cells and small granules containing cells, pheochromoblasts and intermediary cells can be seen as well. Their cytoplasm is sparse, the concentration of dense core vesicles and the innervation density very low. After 8 days of postnatal ontogenesis, pheochromoblasts and intermediary cells are no longer present in the adrenal medulla. In adrenaline-cells and noradrenaline-cells, important processes of growth can be noticed, the cytoplasm has grown in extent, the number of dense core vesicles doubled and the innervation density of single cells triplicated. Only the few small granules containing cells remain small. Under the effect of dexamethasone also in the nuclei of chromaffin cells a transformation of heterochromatin into euchromatin occurs. The increase in number of dense core vesicles is relatively lower than in carotid body chief cells. The significant growth of innervation density during the first postnatal week was inhibited. Our observations suggest that dexamethasone stimulates the synthesis of catecholamines in adrenal medullary cells of newborn rats less pronouncedly than in carotid body chief cells. This could be attributed to the inhibited formation of synapses of growing chromaffin cells and to the in vivo active endocrine counter-regulation.