RSK2 is a new Pim2 target with pro-survival functions in FLT3-ITD-positive acute myeloid leukemia.

Acute myeloid leukemia (AML) with the FLT3 internal tandem duplication (FLT3-ITD AML) accounts for 20-30% of AML cases. This subtype usually responds poorly to conventional therapies, and might become resistant to FLT3 tyrosine kinase inhibitors (TKIs) due to molecular bypass mechanisms. New therapeutic strategies focusing on resistance mechanisms are therefore urgently needed. Pim kinases are FLT3-ITD oncogenic targets that have been implicated in FLT3 TKI resistance. However, their precise biological function downstream of FLT3-ITD requires further investigation. We performed high-throughput transcriptomic and proteomic analyses in Pim2-depleted FLT3-ITD AML cells and found that Pim2 predominantly controlled apoptosis through Bax expression and mitochondria disruption. We identified ribosomal protein S6 kinase A3 (RSK2), a 90 kDa serine/threonine kinase involved in the mitogen-activated protein kinase cascade encoded by the RPS6KA3 gene, as a novel Pim2 target. Ectopic expression of an RPS6KA3 allele rescued the viability of Pim2-depleted cells, supporting the involvement of RSK2 in AML cell survival downstream of Pim2. Finally, we showed that RPS6KA3 knockdown reduced the propagation of human AML cells in vivo in mice. Our results point to RSK2 as a novel Pim2 target with translational therapeutic potential in FLT3-ITD AML.

Drug-induced antibodies during 2-N-methyl-9-hydroxyellipticinium acetate (NSC-264137) treatment: schedule dependency and relationship to hemolysis.

Drug-dependent antibodies were investigated in patients treated with elliptinium acetate, a cytostatic drug with activity in advanced breast cancer. Retrospective analysis of 83 patients, receiving weekly intravenous elliptinium, showed a high incidence of anti-elliptinium antibodies (20%). Hemolysis occurred among antibody-positive patients, apparently related to the antibody titer. The predictability of anti-elliptinium antibodies for hemolysis and the schedule dependency of antibody development was examined prospectively. Among 42 patients treated weekly for at least three courses, 40% developed antibodies. Of 30 patients receiving elliptinium daily for three days every three weeks, none developed either antibodies or hemolysis. Only antibody positive patients, with titers greater than or equal to 32 were at risk for hemolysis. The possible mechanisms are discussed.

Urate oxidase in prevention and treatment of hyperuricemia associated with lymphoid malignancies.

Standard prophylaxis and treatment of malignancy-associated hyperuricemia in the USA has been allopurinol with vigorous hydration, urinary alkalinization and osmotic diuresis. Urate oxidase, the enzyme that converts uric acid to allantoin (a readily excreted metabolite that has 5- to 10-fold higher solubility than uric acid), is an alternative therapy; however, few published findings support this practice. Between February 1994 and December 1996, we administered non-recombinant urate oxidase (Uricozyme) to 126 children with newly diagnosed non-B cell acute lymphoblastic leukemia (ALL) during the first 5 days of chemotherapy with methotrexate, 6-mercaptopurine or both. Their blood levels of uric acid and other indicators of tumor lysis were measured at diagnosis and during treatment and then compared with findings in 129 similarly treated historical controls who had received allopurinol to control hyperuricemia. Clinical responses to urate oxidase were also determined in eight patients with newly diagnosed B cell ALL or advanced-stage non-Hodgkin lymphoma. Patients treated with urate oxidase had rapid and significantly greater decreases in their blood uric acid levels than did the historical controls (median maximal level during treatment, 2.3 vs 3.9 mg/dl, P < 0.001). They also had lower creatinine (0.6 vs 0.7 mg/dl, P = 0.01) and blood urea nitrogen (11 vs 24 mg/dl, P < 0.001) levels. Similar findings were made in the eight cases of B cell ALL or non-Hodgkin lymphoma. None of the patients required dialysis for acute renal failure. Six (4.5%) of the 134 children given urate oxidase had allergic reactions, manifested primarily by urticaria, bronchospasm and hypoxemia. Thus, non-recombinant urate oxidase is a more effective uricolytic agent than allopurinol but is associated with acute hypersensitivity reactions, even in patients without a history of allergy.

Phase II study of elliptinium acetate salvage treatment of advanced breast cancer.

Elliptinium acetate (Celiptium) is an intercalating agent belonging to the ellipticine family. This agent has demonstrated clinical activity as salvage treatment in breast cancer using a weekly regimen. However, its clinical use was hampered by important toxicities such as xerostomia and immune-mediated haemolytic reactions due to development of anti-elliptinium IgM antibodies. We have studied 83 patients previously treated for metastatic breast cancer using elliptinium acetate with a different schedule: 80 mg/m2 daily for 3 consecutive days every 21 days. In 80 evaluable patients, an objective response (complete + partial response) was obtained in 5 of 30 patients with visceral metastases (13%), in 6 of 21 patients with soft tissue metastases (29%), and in 3 of 20 patients with mixed metastases (15%). The overall objective response rate was 14/80 (18%, 95% confidence interval = 10-26%). Moderate to severe xerostomia occurred in 10% of patients, while no anti-elliptinium antibodies or haemolytic reactions were detected using this schedule. No significant haematological toxicity, as usually reported with this drug, was observed. Elliptinium acetate has modest but definite activity as salvage treatment of breast cancer. The 3-week schedule seems as active as and less toxic than the weekly schedule.

Ellipticine derivatives interact with muscarinic receptors.

Ellipticine derivatives or analogues, tetracyclic alkaloids used in human cancer treatment, have been evaluated with regard to their interaction with several neurotransmitter receptors, in order to explain or to predict the side effects which occur in man. These drugs were recently found to be reversible non-competitive inhibitors of cholinesterases. In this study, we have shown that ellipticines are also potent muscarinic antagonists, only 100-fold less active than atropine in inhibiting 50% of the specific binding of (3H) quinuclidinyl benzilate on rat brain preparation of muscarinic receptors. That the interaction with muscarinic receptors is quite unique has been demonstrated by the lack of interaction with three other neurotransmitter receptors. Tertiary amines show relatively less blockade of muscarinic receptors, while substituted ammonium ions are better inhibitors of the QNB binding. The possible mechanisms of in vivo action of these alkaloids is discussed.

[Manifestations of cerebral metastases: diagnostic and therapeutic importance of research on their primary sites in 120 cases]. / Les métastases cérébrales révélatrices: intérêt diagnostique et thérapeutique de la recherche de leur point de départ à propos de 120 observations.

Among 120 cases of cerebral metastases, 62 primary sites were found. The diagnosis of the primary site was confirmed: --after the first investigations in 48 cases (in 90% of cases by anamnestic inquiry, clinical examination or chest X ray); --by the evolution of the disease in 5 cases; --by autopsy in 9 cases. The most frequent primary sites were lung (45%), digestive tract (17.7%), melanoma (8%) and ovary (6.5%). Among the identified cases, 25 received treatment for their primary cancer, but only 4 had a surgical resection. There was no significant difference in mean survival between the 2 groups (defined as primary site known or unknown); over all mean survival was 8 months. The early discovery of cerebral metastases suggests the advanced state of the disease. Therefore, investigations which cause the patient to suffer do not seem justified merely for research purposes.

[Mesenchymal breast sarcomas. Apropos of 25 cases]. / Les sarcomes mammaires mésenchymateux. A propos de 25 cas.

Breast sarcoma are rare, representing 1% of all malignant breast tumours. This is a retrospective study of 25 patients with a breast sarcoma, treated at Institut Gustave Roussy from 1954 to 1981. Thirty six per cent of these arose in a cystosarcoma phyllodes. A variety of histologies were found, the main one being malignant fibrohistiocytoma (44%). Nodal involvement was rare (4%) and, as in other sarcoma, hematogenous spread of metastases was more usual. Local recurrence occurred in 44% of cases and distant metastases (usually pulmonary) in 24%. The 3 year disease-free survival was 60% and the major prognostic factor was the mitotic index. Surgery is the treatment of choice of these tumours, supplemented by local irradiation in those cases where only a tumorectomy has been performed. The role of adjuvant chemotherapy remains undefined.

[2 N methyl 9 hydroxy-ellipticine in treatment of metastatic breast cancers (author's transl)]. / Intérêt de la 2 N-methy-9-hydroxy-ellipticine (NSC 264-137) dans le traitement des cancers du sein métastasés.

A phase II trial was conducted in 57 patients with advanced metastatic breast cancer given 2-N-methyl 9-hydroxy-ellipticine (NMHE) as 100 mg/m2 weekly. Evaluation of response, after at least 4 injections, was possible in 46 patients. Two complete regressions (of 3 and 12 months) and 7 regressions of over 50 p. cent were observed, a total regression rate of 19 p. cent. Regression was mainly observed in cutaneous or subcutaneous metastases. No objective regression was noted for pulmonary or hepatic metastases. Bone metastases were not taken in account when assessing response to treatment. Absence of haematological changes must be emphasized. The most frequent side effects were anorexia, nausea +/- vomiting and dryness of mouth. Major toxicity was intravascular haemolysis, observed in 6 of 175 patients receiving NMHE in the Institut Gustave-Roussy, always controlled by symptomatic treatment. This product, of acceptable efficacy in breast cancer treatment, will probably occupy an original place in anti-cancer chemotherapy because of its lack of myelotoxicity.

Human antibodies to the antineoplastic drug elliptinium: characterization and structure-activity relationships.

Immune-mediated hemolytic disease is a phenomenon rarely encountered with cancer chemotherapeutic agents. Elliptinium, a tetracyclic ammonium compound used in breast and kidney cancer, can induce antibodies that may result in clinical hemolysis. This study reports the characterization of the elliptinium haptenic determinant by use of two different methodologies: a hemagglutination test and a radioimmunoassay. Binding of 12 analogues or derivatives of elliptinium was also studied. Good correlation between the two methods was obtained, indicating that the determinant is most likely located on the quaternary ammonium-containing ring. Furthermore, the hydrophilicity of the drug appears to be an important factor in the antibody reaction. The mechanism of the binding of elliptinium to its antibodies is discussed.

Conjugates of elliptinium acetate with mouse monoclonal anti-alpha-fetoprotein antibodies or Fab fragments: in vitro cytotoxic effects upon human hepatoma cell lines.

Elliptinium acetate (EA) is a new anti-cancer compound displaying cytostatic activity against various malignancies including hepatoma. Using 3 hepatoma cell lines, we compared the in vitro activity of doxorubicin (reference drug), of EA and of conjugates made up with this latter drug and monoclonal antibodies (MAbs). The linkage was performed by a direct oxidation method. Specific immunoconjugates were prepared with an anti-alphafetoprotein (AFP) MAb (AF01) or its Fab fragment (Fab AF01). Non-specific conjugates were obtained with an anti-thyroglobulin MAb (TG01) or its Fab (Fab TG01). Direct membrane injury (51Cr-release), DNA and protein synthesis as well as AFP release were investigated for all compounds. Free EA displayed only weak activity on DNA and protein synthesis, at 10-fold higher molar concentration than doxorubicin. Conjugation of EA with whole AF01 allowed significant potentiation of protein synthesis inhibition without affecting the 3 other tests. In contrast, Fab AF01 x EA conjugates displayed a marked effect in the 4 tests; in particular, this conjugate was at least 100 times more efficient than any other compound when tested in the 51Cr-release test. Neither Fab AF01 nor free EA alone or in combination exhibited such an effect. Fab TG01 x EA conjugate was not directly cytotoxic but potentiated inhibition of DNA and protein synthesis between 2- and 10-fold. The mechanism of the direct cytotoxic effect of anti-AFP Fab x EA conjugate, which has never been described in any other immunodrug model, was investigated.

Phase II study of elliptinium in advanced breast cancer.

A group of 74 patients with advanced breast cancer received elliptinium as second- or third-line treatment (100 mg/m2/week). The objective response rate was 19% (30% in soft tissue metastases), lasting from 3 to 12 months. This drug appears to have no marrow toxicity. Mild to moderate nausea and mouth dryness were the most frequently encountered side effects. Hemolysis occurred in five patients who had an IgM antibody and represents the dose-limiting toxicity. Cumulative renal toxicity (World Health Organization, grade 2) was observed in one of ten patients who had received greater than 2000 mg of elliptinium.

Phase II trial of elliptinium in advanced renal cell carcinoma.

Forty patients with advanced renal cell carcinoma were treated with elliptinium by a weekly infusion of 100 mg/m2. Of 38 evaluable patients, five had an objective response (13.2%). Average response duration was 8 months (range, 5-11). The major dose-limiting toxic effect was induction of antielliptinium antibodies, with the risk of intravascular hemolysis. Elliptinium has modest activity in advanced renal cell cancer and does not produce myelosuppression.