CD10 is a marker for cycling cells with propensity to apoptosis in childhood ALL

CD10 constitutes a favourable prognostic marker for childhood acute lymphoblastic leukaemia. Since correlations between CD10, cell cycle and apoptotic abilities were demonstrated in various cell types, we investigated whether differences existed in the cycling/apoptotic abilities of CD10-positive and CD10-negative B acute lymphoblastic leukaemia cells. Twenty-eight cases of childhood acute lymphoblastic leukaemia (mean age of 6.8 years) were subdivided into two groups according to high (17 cases, 93.2+/-4.5%, MRFI 211+/-82 CD10-positive cells) or low (11 cases, 11.5+/-6.2%, MRFI 10+/-7 CD10-negative cells) expression of CD10. CD10-positive acute lymphoblastic leukaemia cells were cycling cells with elevated c-myc levels and propensity to apoptosis, whereas CD10-negative acute lymphoblastic leukaemia cells had lower cycling capacities and c-myc levels, and were resistant to apoptosis in vitro. A close correlation between all these properties was demonstrated by the observations that the few CD10-positive cells found in the CD10-negative acute lymphoblastic leukaemia group displayed elevated c-myc and cycling capacities and were apoptosis prone. Moreover, exposure of CD10-positive acute lymphoblastic leukaemia B cells to a peptide nucleic acid anti-gene specific for the second exon of c-myc caused inhibition of c-myc expression and reduced cell cycling and apoptotic abilities as well as decreased CD10 expression.

MAGE, BAGE and GAGE gene expression in human rhabdomyosarcomas

MAGE, BAGE and GAGE genes encode tumor-associated antigens that are presented by HLA class I molecules and recognized by CD8(+) cytolytic T lymphocytes. These antigens are currently regarded as promising targets for active, specific tumor immunotherapy because MAGE, BAGE and GAGE genes are expressed in many human cancers of different histotype and are silent in normal tissues, with the exception of spermatogonia and placental cells. MAGE, BAGE and GAGE gene expression has been extensively studied in different tumors of adults but is largely unknown in many forms of pediatric solid cancer. Using RT-PCR, we analyzed MAGE-1, MAGE-2, MAGE-3, MAGE-4, MAGE-6, BAGE, GAGE-1,-2 or -8 and GAGE-3,-4,-5,-6 or -7b gene expression in 31 samples of pediatric rhabdomyosarcoma, the most frequent form of malignant soft tissue tumor in children. MAGE genes were expressed in a substantial proportion of patients (MAGE-1, 38%; MAGE-2, 51%; MAGE-3, 35%; MAGE-4, 22%; MAGE-6, 35%), while expression of BAGE (6%); GAGE-1, GAGE-2 and GAGE-8 (9%); and GAGE-3, GAGE-4, GAGE-5, GAGE-6 and GAGE-7B (16%) was less frequent. Overall, 58% of tumors expressed at least 1 gene, and 35% expressed 3 or more genes simultaneously. Our data suggest that a subset of rhabdomyosarcoma patients could be eligible for active, specific immunotherapy directed against MAGE, BAGE and GAGE antigens.

All-trans retinoic acid and interferon-alpha in the treatment of a patient with resistant metastatic osteosarcoma

BACKGROUND

A boy age 14 years who was in complete remission from Stage IIB small cell osteosarcoma, which was misdiagnosed as Ewing sarcoma and consequently was treated, developed inoperable lung metastases when he was off therapy. He received second-line treatment for recurrent Ewing sarcoma, including chemotherapy and radiotherapy, and obtained only a temporary response. A compassionate treatment with all-trans retinoic acid (ATRA) and interferon-alpha (IFNalpha) was then undertaken.

METHODS

The patient initially was treated according to the national SE91 protocol for nonmetastatic Ewing sarcoma. After a bilateral pulmonary recurrence, he received second-line chemotherapy and irradiation of the largest metastasis, with a temporary partial response. The patient was then treated with a combination of oral ATRA (90 mg/m(2) for 3 days per week) and subcutaneous IFNalpha (3 x 10(6) U/m(2) 5 days per week) for 4 months. The same therapy also was administered for the control of residual disease after surgery for a total duration of 1 year of ATRA/IFN treatment. During the first 3 weeks of therapy, ATRA pharmacokinetics were studied.

RESULTS

After progression of the patient's disease, despite the administration of first-line and second-line chemotherapy, combined treatment with ATRA/IFNalpha yielded a partial remission, which allowed surgical resection of the largest metastasis. The same therapy was effective in preventing tumor recurrence after incomplete removal of the remaining metastases. Treatment was well tolerated, and the patient is in stable complete remission 14 months after the end of therapy. The pharmacokinetics results confirmed the indication of an intermittent schedule for oral ATRA therapy.

CONCLUSIONS

ATRA/IFNalpha treatment may be considered as an alternative approach in the treatment of patients with metastatic osteosarcoma who have disease that is resistant to conventional chemotherapy and in the treatment of patients with minimal tumor residue.

Concomitant amplification and expression of PAX7-FKHR and MYCN in a human rhabdomyosarcoma cell line carrying a cryptic t(1;13)(p36;q14)

Alveolar rhabdomyosarcoma (ARMS) is associated with the specific chromosomal translocation (2;13)(q35;q14) or its rarer variant t(1;13)(p36;q14), which produces the fusion gene PAX7-FKHR. Here we describe the human cell line RC2, derived from an ARMS, which harbors a cryptic t(1;13)(p36;q14) and concomitantly shows amplification of the PAX7-FKHR fusion gene and of the MYCN oncogene. The t(1;13) and MYCN oncogene were studied by standard cytogenetic analysis and molecular techniques. The reverse transcriptase polymerase chain reaction demonstrated the expression of PAX7-FKHR mRNA in RC2 cells, although karyotype analysis failed to demonstrate a t(1;13)(p36;q14) chromosomal translocation or a derivative 13 chromosome. Double minute chromosomes were detected in all the metaphases studied. Fluorescence in situ hybridization analysis revealed multiple copies of the PAX7-FKHR fusion gene localized exclusively on a subset of double minutes, whereas multiple copies of MYCN were identified on other double minute chromosomes. Southern-blot analysis demonstrated that RC2 cells contain approximately 20 copies of the MYCN oncogene. So far no continuous RMS cell line carrying the t(1;13)(p36;q14) has been described, and PAX7-FKHR and MYCN amplifications have always been reported to occur separately in rhabdomyosarcoma (RMS). The availability of an ARMS cell line that harbors the t(1;13)(p36;q14) constitutes a useful tool for further understanding the role of the PAX7-FKHR fusion gene in RMS oncogenesis and may improve knowledge of the possible relation between PAX7-FKHR and MYCN amplification.

Improved long-distance polymerase chain reaction for the detection of t(8;14)(q24;q32) in Burkitt's lymphomas

The t(8;14)(q24;q32), involving MYC gene (8q24) and the immunoglobulin heavy chain (IgH) locus (14q32), represents about 75% of all translocations in Burkitt's lymphoma (BL). Due to the great variability of the breakpoint region, a standard polymerase chain reaction assay is not sufficient for the detection of this chromosomal translocation. The availability of new and more efficient DNA polymerases that allow the amplification of genomic fragments many kilobase-pairs long, makes it possible to identify the t(8;14) in BL cells by long-distance polymerase chain reaction (LD-PCR). We have established a simplified and efficient LD-PCR for the detection of t(8;14)(q24;q32) that relies on the use of one primer specific for MYC exon II combined, in different reactions, with four primers for the IgH locus: three for the constant regions Cmu, Cgamma, and Calpha, and one for the joining region (JH). We first studied seven BL cell lines and optimized LD-PCR reaction for analysis of tumor specimens. Five of seven cell lines were positive for the t(8;14), whereas two lines derived from endemic BL were negative, as expected. Of 15 biopsies obtained from pediatric BL and subsequently analyzed, 13 (87%) were positive for the translocation detected by LD-PCR and showed a product ranging in size from 2.0 to 9.5 kb. Cmu region was involved in 6 cases, Cgamma and Calpha in 2 cases each, and JH in 3 cases. Interestingly, 2 of the tumors positive for JH showed a second, larger PCR product with the Calpha- and Cgamma-specific primer, respectively. We established that our LD-PCR method could detect 10(-3) BL cells within a population of hematopoietic cells lacking the translocation. In conclusion, our LD-PCR method represents a fast, highly sensitive, and specific tool to study sporadic BL and to detect minimal disease and residual disease in patients affected by t(8;14)-positive lymphomas.

High-dose melphalan with autologous stem-cell rescue in metastatic rhabdomyosarcoma

PURPOSE

The European Collaborative MMT4-91 trial was conducted as a prospective nonrandomized study to evaluate the potential benefit of high-dose melphalan as consolidation of first complete remission in children with stage IV rhabdomyosarcoma.

PATIENTS AND METHODS

Fifty-two patients in complete remission after six courses of chemotherapy received "megatherapy": 42 received melphalan alone, whereas 10 received melphalan in combination with etoposide, carboplatin/etoposide, or thiotepa/busulfan and etoposide. The outcome of this group of patients was compared with that observed in 44 patients who were also in complete remission after six courses of identical chemotherapy (plus surgery or radiotherapy) but went on to receive a total of up to 12 courses of conventional chemotherapy (four cycles). No differences were found between the two groups regarding clinical characteristics, chemotherapy received before complete remission, or response to chemotherapy. In particular, there was no significant difference between the groups for site of primary tumor, histologic subtype, age at presentation, presence of bone or bone marrow metastases, or number of metastases.

RESULTS

The 3-year event-free survival (EFS) and overall survival (OS) rates were 29.7% and 40%, respectively, for those receiving high-dose melphalan or other multiagent high-dose regimens and 19.2% and 27.7%, respectively, for those receiving standard chemotherapy. The difference was not statistically significant (P =.3 and P =.2 for EFS and OS, respectively). There was a significant prolongation in the time from the last day of high-dose chemotherapy or the end of chemotherapy cycle 4 to the time of relapse in those receiving megatherapy (168 days for patients receiving megatherapy v 104 days for those receiving standard therapy; P =.05).

CONCLUSION

The addition of a high-dose alkylating agent to consolidation therapy may have prolonged progression-free survival in this poor-risk patient group, but it did not significantly improve the ultimate outcome.

Effects of all-trans retinoic acid and interferon alpha in peripheral neuroectodermal tumor cell cultures and xenografts

Peripheral neuroectodermal tumors (PNET) have an unsatisfactory outcome when treated with standard approaches. Among novel treatments, the use of biological response modifiers has rarely been reported in this group of malignancies. We have previously demonstrated that both all-trans retinoic acid (ATRA) and interferon á (IFNá) can inhibit proliferation of human PNET cells and that ATRA can up-regulate IFNá receptor expression in vitro. In this study we evaluated the anti-tumor effects of ATRA and IFNá in PNET cells in vitro and in a human PNET xenograft model, using CHP100 cells. A synergistic inhibitory effect of ATRA and IFNá was observed on CHP100 cells in vitro. On the contrary, a significant inhibition of tumor growth was observed in mice treated with ATRA alone, whereas neither IFNá nor the combination of ATRA and IFNá, reached a statistically significant anti-tumor effect. Histologic examination of tumors revealed the presence of necrosis upon treatment with IFNá, whereas almost no necrosis, but a more differentiated morphology, confirmed by electron microscopy analysis, was associated with the ATRA containing treatments. Taken together these data show an in vitro and in vivo anti-tumor activity of ATRA in human PNET cells, although no synergism of ATRA and IFNá was observed in our xenograft model.

Normal and rearranged PAX3 expression in human rhabdomyosarcoma

PAX3, a member of the PAX-gene family, encodes a nuclear transcription factor that is transiently expressed in the neural tube and in muscle progenitor cells and regulates embryonal development in the mouse. Together with the FKHR gene it is involved in the t(2;13)(q35;q14), a specific translocation associated with alveolar rhabdomyosarcoma (ARMS). As a consequence of the rearrangement two chimeric transcripts originate: FKHR-PAX3 and PAX3-FKHR. We studied the expression of wild type PAX3 and the chimeric transcripts originating from the t(2;13) in a series of 23 rhabdomyosarcomas (RMS) of childhood, by reverse transcriptase polymerase chain reaction (RT-PCR). Wild type PAX3 was detected in 48% of the RMS, whereas another 39% were positive only after nested PCR. Normal adult-skeletal muscle showed a very weak expression of PAX3, but fetal muscle did not express PAX3. PAX3-FKHR was found in 11 of 15 alveolar RMS, 7 of which were positive also for the reciprocal transcript, whereas no RMS expressed FKHR-PAX3 alone. These results confirm that the PAX3-FKHR transcript is specifically associated with the alveolar RMS and that it is a more sensitive marker of the t(2;13) than the reciprocal product FKHR-PAX3. Furthermore, the finding of PAX3 expression with or without PAX3-FKHR transcript in the great majority of the cases raises the question of whether PAX3 expression could play a role in the pathogenesis of RMS.

Detection of the MyoD1 transcript in rhabdomyosarcoma cell lines and tumor samples by reverse transcription polymerase chain reaction

Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma of childhood. Diagnosis of RMS can be difficult when it appears as a small round-cell tumor without evidence of differentiation. Recently, a set of regulatory proteins expressed during skeletal muscle development has been described. Among them, MyoD1 has been detected by Northern blot and immunohistochemical analyses in normal skeletal muscle and RMS. Given the relevance of this marker in the diagnosis of RMS, we developed an assay to evaluate the expression of MyoD1 mRNA in small tissue specimens by reverse transcription polymerase chain reaction. Specificity and sensitivity of the assay was determined in a series of 25 tumor cell lines and 39 pediatric tumor samples, including 35 RMSs. Subsequently, we studied the expression of MyoD1 in bone marrow and peripheral blood stem cell specimens. We detected the MyoD1 transcript in normal skeletal muscle and in almost all RMSs, whereas no expression was found in non-RMS samples or in normal hematopoietic tissues. This assay showed high sensitivity and specificity, and it could be a useful molecular tool for the diagnosis of RMS within small roundcell tumors of childhood and for the detection of minimal bone marrow and peripheral blood stem cell involvement in children with RMS, regardless of the histological subtype.

In vitro and in vivo antitumor effects of retrovirus-mediated herpes simplex thymidine kinase gene-transfer in human medulloblastoma

Herpes simplex virus thymidine kinase gene (HSVtk) transfer together with treatment with the prodrug ganciclovir (GCV) represents the most commonly used suicide gene approach for the gene therapy of human central nervous system malignancies. Despite encouraging results reported in clinical trials conducted in adults, very little is known about the feasibility of this approach for the treatment of CNS tumors of childhood. We studied the effects of the HSVtk/GCV system on human medulloblastoma cells in vitro and in vivo. The transfer of tk gene to medulloblastoma cells was capable of mediating cell suicide in vitro and in vivo upon treatment with GCV, but the overall effect in vivo appeared to be suboptimal. The relatively low sensitivity of the medulloblastoma cells to viral infection and a limited bystander effect, coupled with a low expression of connexin-43 protein, might partially explain these results. Whether this is a peculiarity of the cell line studied or a general characteristic of medulloblastoma remains to be determined. These findings should be taken into account for the future planning of gene therapy trials for human medulloblastoma.

Second malignant neoplasms in patients treated on SIOP Wilms tumour studies and trials 1, 2, 5, and 6

The incidence of second malignant neoplasms (SMNs) was investigated among 1,988 patients with complete data, enrolled in the SIOP Wilms tumor trials and studies 1, 2, 5, and 6, treated between September 1971 and October 1987. By the end of 1992, eight SMNs were documented, whereas only 1.3 were expected (standardized incidence ratio [SIR] = 4.15; 95% CI = 1.79, 8.17). The risk increases in the first 10 years from diagnosis, while no apparent excess of risk is observed in the subsequent periods. This finding however is difficult to interpretdue to the low statistical power. The cumulative incidence of a second cancer observed at 15 years after Wilms tumor diagnosis was 0.65%. Six SMNs were registered in the cohort of patients treated in the SIOP studies 1, 2 and 5 (999 cases) compared to the two cases observed in the SIOP6 cohort (989 cases). If the suggested reduced incidence of second cancers between SIOP1-5 and SIOP6 patient cohorts is confirmed by longer follow-up, it might reflect changes in the treatment protocols.

Expression of type I interferon receptor in solid tumors of childhood

Interferon alpha (IFN alpha) is used as an antineoplastic agent, both in hematopoietic malignancies and in solid tumors, because of its immunomodulatory action and direct antitumor activity. IFN alpha binds to specific cell-surface receptors that mediate its biologic activity. We studied the expression of IFN alpha receptors in pediatric solid tumors by use of the monoclonal antibody IFNaR3, which specifically recognizes the alpha subunit of the IFN Type I receptor. In three cell lines derived from those tumors, we determined the structure of the receptors by affinity cross-linking and immunoprecipitation techniques, and we determined their ability to mediate an antiproliferative effect. All of the tumor specimens studied by immunocytochemical analysis, including neuroblastomas, primitive neuroectodermal tumors, and rhabdomyosarcomas, stained positive for the IFN alpha receptor antibody, although in some cases immunoreactivity was weak. The three cell lines, derived from a neuroblastoma, a primitive neuroectodermal tumor, and a Ewing's sarcoma, respectively, showed the same pattern of IFN alpha receptor expression, both by affinity crosslinking and immunoprecipitation assays. Treatment with IFN alpha of those cell lines induces growth inhibition in vitro. These results suggest that IFN Type I receptor might be expressed in most solid tumors of childhood and that its structure is identical to the receptor expressed by the majority of hematologic malignancies.

Response of previously untreated metastatic rhabdomyosarcoma to combination chemotherapy with carboplatin, epirubicin and vincristine

This study aimed to assess the response to a novel combination chemotherapy containing carboplatin plus epirubicin in previously untreated children with metastatic rhabdomyosarcoma. 81 children (< or = 18 years) were treated between 1989 and 1994 with a combination of carboplatin, epirubicin and vincristine, given as initial therapy as part of a multicentre European trial (SIOP Intergroup Study of Stage IV Malignant Mesenchymal Tumours in Children). The chemotherapy regimen (CEV) was: carboplatin 500 mg/m2 plus epirubicin 150 mg/m2 administered on day 1, and vincristine 1.5 mg/m2 administered on days 1 and 7. Response was evaluated at day 21. 2 patients achieved complete remission and 41 patients partial remission, with an overall response rate of 53% (95% confidence interval 45-76%). Three patients showed progressive disease (4%). Toxicity was mainly haematological, with 52% experiencing grade IV neutropenia and 34% grade IV thrombocytopenia. Mucositis and infections were not severe. There were no toxic deaths. The combination of carboplatin, epirubicin and vincristine is effective and well tolerated in patients with metastatic rhabdomyosarcoma.

Episome generated C-myc antisense RNA inhibits growth and tumorigenicity of a human neuroendocrine tumor-cell line

The neuroepithelioma cell line CHP100 expresses low but detectable amounts of N-myc protein together with large amounts of c-myc protein. We have recently demonstrated that antisense inhibition of N-myc expression in CHP100 cells leads to decreased in vitro growth and alterations in cellular morphology without affecting tumorigenicity in nude mice. In this study we report the construction of an episomally replicating vector designed to generate RNA antisense to part of the human c-myc gene. Such a Vector is able to inhibit c-myc expression in cell lines carrying multiple copies of the gene. Inhibition of c-myc expression leads to a decrease of in vitro growth and cloning efficiency and in vivo tumorigenicity of CHP100 cells. Our findings suggest that N-myc and c-myc subserve different functions in regulating the biology of CHP100 cells.