Neoadjuvant chemotherapy combined with regional hyperthermia (RHT) for locally advanced primary or recurrent high-risk adult soft-tissue sarcomas (STS) of adults: long-term results of a phase II study.

In this phase II study, activity and safety of neoadjuvant regional hyperthermia (RHT) combined with chemotherapy was investigated in 59 patients with primary advanced or recurrent high-risk soft-tissue sarcoma (STS). Patients received four EIA cycles consisting of etoposide, ifosfamide and doxorubicin combined with RHT followed by surgical resection and adjuvant treatment. The overall objective response (OR) rate was 17%, with one complete (2%) and eight partial (15%) responses. In addition, 13 minor responses (25%) were seen. At time of surgery, complete necrosis (pCR) occurred in 6 patients and >75% necrosis (favourable histological response (FHR)) in 12 patients. At the completion of protocol treatment, 36 patients were rendered disease-free which was significantly associated with the initial radiographic and/or pathological tumour response (P=0.004). Treatment-related toxicity was acceptable overall. At a medium follow-up of 82 months, local treatment failure occurred in 33 patients, median overall survival (OS) was 52 months, and the 5-year survival rate was 49% (95% confidence interval (CI): 36-61%). OS which did not differ for extremity versus non-extremity STS (P=0.21) was better for patients responding to EIA combined with RHT (P<0.01).

Treatment of primary, recurrent or inadequately resected high-risk soft-tissue sarcomas (STS) of adults: results of a phase II pilot study (RHT-95) of neoadjuvant chemotherapy combined with regional hyperthermia.

The efficacy of thermochemotherapy in adult patients with primary, recurrent or inadequately resected non-metastatic high-risk soft-tissue sarcomas (STS) was assessed. 54 patients were prospectively treated with four cycles of etoposide, ifosfamide and doxorubicin (EIA) combined with regional hyperthermia (RHT) followed by surgery, another four cycles of EIA without RHT and external beam radiation. The objective response rate was 16% and at a median follow-up time of 57 months, the 4-year estimated rates of local failure-free survival (LFFS), distant metastasis-free survival (DMFS), event-free survival (EFS) and overall survival (OS) were 59% (95% confidence interval (CI) 45-73%), 59% (95% CI 44-73%), 26% (95% CI 14-38%) and 40% (95% CI 27-53%), respectively. OS was in favour of patients responding to neoadjuvant treatment (P=0.073). In comparison to a preceding phase II study including pre- and postsurgical thermochemotherapy (RHT-91), at a 4-year follow-up the RHT-95 study cohort showed an inferior LFFS rate (P=0.027), but this did not affect DMFS (P=0.558) or OS (P=0.126). Hence, postsurgical thermochemotherapy seems critical for local tumour control without affecting survival.

Hyperthermia in oncology.

The purpose of this article is to provide an overview on the current clinical application of hyperthermia combined with conventional treatment modalities (e.g. ionizing radiation, chemotherapy) in the treatment of malignant disease. The clinical application of hyperthermia with increase of tissue temperatures (range 40-44 degrees C) has been integrated in multimodal anti-cancer strategies. This review describes selected phase I or II (n = 17) and phase III trials (n = 16) investigating the effect of hyperthermia combined with radiotherapy (n = 10 trials), chemotherapy (n = 15 trials), or both (n = 8 trials) in a total of more than 2200 patients. The trials were performed in a variety of solid tumours (e.g. melanoma, head and neck cancer, breast cancer, cancer of the gastrointestinal or urogenital tract, glioblastoma, sarcoma) in paediatric or adult patients. Profound research has produced a scientific basis for the simultaneous application of hyperthermia in combination with ionizing radiation and/or systemic chemotherapy. Hyperthermia is becoming more accepted clinically, due to the substantial technical improvements made in achieving selected increase of temperatures in superficial and deep-seated tumours. At present, the combination of hyperthermia and chemotherapy or radiochemotherapy is further tested within clinical protocols (phase II/III) in order to improve local tumour control and relapse-free survival in patients with high-risk or advanced tumours of different entities.

Improving stable transfection efficiency: antioxidants dramatically improve the outgrowth of clones under dominant marker selection.

Many cell lines are sensitive to growth at low cell density and undergo apoptosis induced by oxidative stress if the cell density is decreased below a critical threshold. In stable transfection experiments this cell density-dependent growth may be the limiting factor, since during drug selection the cell density falls below the critical threshold, precluding outgrowth of transfected clones. We describe here a simple protocol for the establishment of stably transfected human B cell lines making use of the protective action of antioxidants. The protocol includes: (i) seeding the cells in medium supplemented with sodium pyruvate, alpha-thioglycerol and bathocuproine disulfonate; (ii) delaying the onset of dominant marker selection to improve recovery of the cells after electroporation. Stably transfected clones have thus been obtained from Burkitt's lymphoma lines, which have been regarded as untransfectable. Using this protocol the stable transfection efficiency with episomal plasmids approaches the transient transfection efficiency, indicating that virtually every transfected cell can be established as a stably transfected clone. This protocol should also prove useful for other cell lines, e.g. neuronal cells, having similar sensitivities to oxidative stress.

Apoptosis in Burkitt lymphoma cells is prevented by promotion of cysteine uptake.

Burkitt lymphoma (BL) cells are highly sensitive to suboptimal growth conditions and undergo apoptosis when seeded at reduced serum concentration or low cell density. Irradiated fibroblasts can protect BL cells from apoptosis induced by lowering the serum concentration or cell density through secretion of a survival- and proliferation-promoting activity which is soluble and labile. Murine B cells have a restricted uptake capacity for cystine and require cysteine for proliferation, which can be supplied efficiently by feeder cells. Therefore, we have studied the role of cysteine and other compounds with free thiol groups for survival and proliferation of BL cells. Cysteine, when added alone, exerted strong toxicity on BL cells. This toxicity could be counteracted by the addition of catalase, pyruvate or bathocuproine disulfonate (BCS), all of which interfere with the production of hydrogen peroxide. Inhibition of the toxicity of cysteine was necessary to unravel the survival- and growth-promoting activity of cysteine at low cell density. Alpha-thioglycerol, beta-mercaptoethanol and dithiothreitol had similar toxic activity in the absence of catalase, pyruvate and BCS and, through stimulation of cysteine uptake and glutathione synthesis, displayed a similar survival- and growth-promoting activity in the presence of the protective agents. The survival- and proliferation-inducing activity of thiol compounds in the presence of catalase, pyruvate and BCS was not associated with induction of BCL-2 or BAX. Cysteine/cystine uptake and the intra/cellular glutathione level are thus important parameters, determining the susceptibility vs. resistance of BL cells to apoptosis.

Absence of c-kit receptor and absent proliferative response to stem cell factor in childhood Burkitt's lymphoma cells.

The cytokine stem cell factor (SCF) synergizes with interleukin-7 (IL-7) to enhance the proliferation of pre-B cells. To examine the role of SCF and its receptor, c-kit, in the pathogenesis of pediatric Burkitt's lymphomas (BL), we investigated the expression of SCF and c-kit in BL cells and the mitogenic activity of SCF on BL cells. A panel of 13 BL cell lines and 7 fresh biopsy tumors was investigated. BL cells were stimulated either by Epstein-Barr virus (EBV) infection or by different reagents and cytokines, and expression of SCF and c-kit was studied on the mRNA level by Northern blot analysis and reverse-transcriptase polymerase chain reaction (RT-PCR), followed by Southern blotting. c-kit expression was also studied by fluorescence-activated cell sorting and by crosslinking of digoxigenin-labeled recombinant human SCF to the cell surface. Proliferation of BL cell lines was measured by 3H-thymidine incorporation. Low-level expression of c-kit mRNA was detected in 2 of 13 unstimulated BL cell lines and in 1 fresh BL tumor. One cell line showed upregulation of c-kit mRNA with A23187 and downregulation with phorbol myristate acetate. Neither c-kit nor SCF could be detected in any other cell line under any condition of stimulation as analyzed by Northern blot analysis, RT-PCR followed by Southern blot analysis, crosslinking, and immunofluorescence. No response to SCF was seen in 3H-thymidine incorporation assays. We conclude that most BL cells express neither SCF nor c-kit and that the low-level expression of c-kit in some BL cells most likely has no biologic significance.

Irradiated fibroblasts protect Burkitt lymphoma cells from apoptosis by a mechanism independent of bcl-2.

When cells of fresh Burkitt lymphoma (BL) biopsies are explanted into tissue culture, their survival and growth are greatly dependent on the presence of a feeder layer of irradiated fibroblasts. To investigate the nature of this feeder dependence, we characterized the growth requirements of a panel of Epstein-Barr Virus (EBV)-negative and -positive BL cell lines in both the absence and the presence of feeder cells in vitro. Four EBV-negative BL lines and 4 EBV-positive lines displaying the phenotype of BL cells in vivo required high cell density for proliferation in the absence of feeder cells, but grew out as single-cell clones when seeded on irradiated human fibroblasts. EBV-positive BL cell lines which had acquired an activated phenotype similar to that of lymphoblastoid cell lines required much lower cell densities for autonomous proliferation. The EBV-negative Burkitt lymphoma line BL70 was used as a model to study the feeder-cell dependence in more detail. BL70 cells grew in the absence of feeder cells only at high cell density and at high FCS concentration. In the presence of feeder cells, BL70 cells became clonogenic even at greatly reduced FCS concentration. A decrease in either cell density or FCS concentration induced apoptosis. Supernatants from feeder cells and from BL70 cells growing autonomously at high cell density were unable to substitute for the survival and growth-promoting effect of the feeder cells. Protection of Burkitt lymphoma cells from apoptosis by co-cultivation with irradiated fibroblasts was not mediated by induction of bcl-2.(ABSTRACT TRUNCATED AT 250 WORDS)

Mapping chromosomal breakpoints of Burkitt's t(8;14) translocations far upstream of c-myc.

To analyze the region upstream of c-myc, a number of novel probes were established. These were generated by chromosomal walking starting from the breakpoint of the chromosomal translocation of the B-cell line 380 and by cloning the breakpoint of the translocation of the Burkitt lymphoma cell line IARC/BL72. Using the newly isolated probes a detailed physical map of 500 kilobases of the region upstream of c-myc was established applying pulsed-field gel electrophoresis. The chromosomal breakpoint of IARC/BL72 cells was mapped to a site 55 kilobases 5' of c-myc. A region 20 kilobases in length and containing the breakpoints of 380, EW36, P3HR-1, and Daudi cells was identified 170-190 kilobases upstream of c-myc. In addition the HPV18 integration site in HeLa cells was located between 340 and 500 kilobases 5' of c-myc. The probes were used to define the c-myc amplification units in Colo320-HSR and HL60 cells as well as in four cases of small cell lung cancer. Evidence is provided that the amplicon of HL60 cells is discontinuously organized.

Variable breakpoints in Burkitt lymphoma cells with chromosomal t(8;14) translocation separate c-myc and the IgH locus up to several hundred kb.

In about 80% of Burkitt's lymphoma cases, the tumour cell harbours a reciprocal chromosomal translocation which invariably transposes the coding exons 2 and 3 of c-myc from chromosome 8 to the immunoglobulin heavy chain locus on chromosome 14. Those t(8;14) translocations which disrupt chromosome 8 within or close to the c-myc gene are well documented. In this study we have focussed on t(8;14) translocations with the chromosomal breakpoint far upstream of c-myc. We analyzed the breakpoint position in 44 BL cell lines with t(8;14) translocations of different geographical origin and identified 9 cell lines with the breakpoint more than 14 kb upstream of c-myc. In these cell lines the positions of the translocation junctions on the derivative chromosomes 8q- and 14q+ were mapped by pulsed field gel electrophoresis and multicolour fluorescence in situ hybridization. The breakpoints occur at distances between 55 and more than 340 kb upstream of c-myc with no preferential site on chromosome 8. On chromosome 14, however, the translocation breakpoints are clustered in a narrow region 5' of the intron enhancer of the immunoglobulin heavy chain gene. In 7 of 9 cases, the enhancer is fused to the c-myc bearing sequences of chromosome 8. In two cases, the translocation has occurred in switch mu and downstream of C mu, respectively. The impact of these results with respect to the hypothesis, that cis-regulatory sequences from the immunoglobulin heavy chain locus can deregulate c-myc expression in a manner sufficient for tumour formation, is discussed.

Expression of the APO-1 antigen in Burkitt lymphoma cell lines correlates with a shift towards a lymphoblastoid phenotype.

APO-1 is a cell surface molecule that induces apoptosis when ligated with the monoclonal antibody anti-APO-1. Expression of APO-1 and response to anti-APO-1 was investigated in a number of Epstein-Barr virus (EBV)-positive and -negative Burkitt lymphoma (BL) cell lines, in EBV-immortalized lymphoblastoid cell lines, and in cells from fresh BL biopsies. APO-1 was not expressed in EBV-negative cell lines and in EBV-positive BL cell lines with a phenotype corresponding to BL tumor biopsy cells (CD10+, CD21-, CD23-, CD30-, CD39-, CDw70-, CD77+). Accordingly, fresh BL cells obtained from three BL biopsies were APO-1 negative. EBV-positive BL cell lines that had acquired a lymphoblastoid phenotype (CD10-, CD21+, CD23+, CD30+, CD39+, CDw70+, CD77-) upon prolonged in vitro cultivation, as well as normal B-lymphoblastoid cell lines, expressed a high density of APO-1. APO-1 may, therefore, be regarded as a B-cell activation marker. APO-1 expression is not the only prerequisite for anti-APO-1-induced apoptosis because 6 of 7 APO-1-expressing EBV-positive BL cell lines were not sensitive to anti-APO-1, whereas all lymphoblastoid cell lines were killed by anti-APO-1. The sensitivity of lymphoblastoid cell lines to anti-APO-1-mediated apoptosis may open a new therapeutic approach for the treatment of EBV-induced lymphoproliferative lesions in immunocompromised individuals, because these are composed of cells with a lymphoblastoid phenotype.

Molecular analysis of Hodgkin's disease-derived cell lines.

Three Hodgkin's disease-derived cell lines were analysed for the organization of immunoglobulin and T cell receptor genes, for the expression of the interleukin 2 (IL-2) receptor gene, and for the cellular oncogene c-myc. All three cell lines have characteristic genotypic markers of lymphoid cells and can be classified as immature lymphoid cells with respect to the incomplete expression of their antigen receptor genes. This immature genotype is in contrast to the expression of activation antigens Ki-1 (CD 30), IL-2 receptor (CD 25), and HLA-DR. The results obtained are in agreement with studies obtained from primary Hodgkin's lymphomas, which are activated by as yet unknown mechanisms.

Phenotype versus immunoglobulin and T-cell receptor genotype of Hodgkin-derived cell lines: activation of immature lymphoid cells in Hodgkin's disease.

Three Hodgkin-derived cell lines (L428, L540, and CO) were studied for rearrangements and expression of immunoglobulin and T-cell receptor genes, and their genotype was compared to the phenotype. As far as the genotype is concerned, all 3 cell lines have characteristics of lymphoid cells; L428 of B, and L540 and CO of T-cell origin. L428 cells have one Ig heavy chain allele rearranged to C gamma and transcribed into RNA, while the second is deleted. Furthermore, L428 cells show an unusual immunoglobulin kappa light chain gene rearrangement involving deletion of the kappa constant gene in one allele, while the remaining kappa and lambda loci are in germline configuration. L540 and CO have, in contrast to L428 cells, the immunoglobulin genes in germline and T-cell receptor genes rearranged. The T-cell receptor beta and gamma genes are rearranged in both L540 and CO, whereas a rearrangement in the alpha locus was detected in L540 cells only. RNA of the size of functional beta chain transcripts was found in CO cells and of the size of functional alpha chain transcripts in L540 cells. All 3 cell lines are classified as immature lymphoid cells with respect to the limited expression of B- and T-cell antigens, respectively, and to the incomplete expression of their antigen receptor. The immaturity of lymphoid differentiation contrasts with the expression of activation antigens, i.e. Ki-1, Ki-24, HLA-DR, and IL-2 receptor. The immaturity of the cells excludes the possibility that the cells were activated along the physiological pathway, i.e. by interaction of the cell with antigen. The results obtained on the cell lines are in accordance with in vivo studies and suggest that Hodgkin and Sternberg-Reed cells are immature lymphoid cells which are activated by a still unknown mechanism.