Cytotoxic activity of cyclosporin A and [3-keto-Bmt1]-[Val2]-cyclosporin (SDZ PSC 833) on tumour cells from patients with haematological malignancies

PPP3CB contributes to poor prognosis through activating nuclear factor of activated T-cells signaling in neuroblastoma

We previously identified a gain-of-function mutation in PPP3CB in a neuroblastoma (NB) with MYCN amplification. Here we investigated the functional and clinical role of PPP3CB in NB. High PPP3CB expression was an independent indicator predicting poor prognosis of NB. Overexpression of wildtype or mutated PPP3CB (PPP3CBmut) promoted cell growth, but PPP3CB knockdown decreased cell growth in NB cells. Forced expressions of PPP3CB and PPP3CBmut activated NFAT2 and NFAT4 transcription factors and inhibited GSK3β activity, resulting in the increase in the expressions of c-Myc, MYCN, and β-catenin, which were downregulated in response to PPP3CB knockdown. Treatment with calcineurin inhibitor cyclosporin A (CsA) or FK506 suppressed cell proliferation and induced apoptotic cell death in both MYCN-amplified and MYCN-non-amplified NB cell lines. Expression of PPP3CB protein was decreased in response to two calcineurin inhibitors. c-Myc, MYCN, and β-catenin were downregulated at the mRNA and protein levels in CsA or FK506-treated NB cells. Our data indicate that elevated expression of PPP3CB and the expression of its constitutively active mutant contribute to the aggressive behavior of NB tumors and therefore suggest that inhibition of calcineurin activity might have therapeutic potential for high-risk NB.

Calcineurin inhibitors and rapamycin: cancer protection or promotion?

Since the introduction of cyclosporin A (CsA) in the early 1980s, the use of immunosuppressants has markedly increased. Already established drugs have proved effective in the treatment of a wide range of diseases outside transplantation medicine and new immunosuppressants have been developed for more specific indications such as psoriasis and atopic dermatitis. Patients in transplantation medicine as well as in dermatology have benefited significantly from systemic and topical application of both new and established drugs. But are these drugs without risks? Cancer-protecting effects have been reported for some of the available immunosuppressants. Conversely, other publications and the issue of a black box warning by the US Food and Drug Administration have increased concerns about cancer-promoting effects. Knowledge of the specific effects as well as adverse effects is paramount to ensure an application that is safe and beneficial for the patient. Here we review the mechanisms of action and therapeutic potential, and critically review recent literature with respect to possible carcinogenic side effects of systemic and topical CsA, tacrolimus, pimecrolimus and rapamycin.

Successful treatment of B cell chronic lymphocytic leukemia-associated severe paraneoplastic pemphigus with cyclosporin A

Since the first description of paraneoplastic pemphigus, several cases have been described in the literature. However, curative therapy is usually a challenge to the physicians treating this disease. Several publications are available discussing the efficacy of steroids, cyclophosphamide and cyclosporin A. Recently, a report of the successful use of rituximab was also published. However, the use of cyclosporin A is controversial in the case of B cell malignancies, as there are reports showing the cytotoxic effect of this drug on B cells. However, other authors report no effect, or even unwanted effects resulting in B cell proliferation. We report the case of a 50-year-old Caucasian male. He developed a B cell lymphoma consisting of CD5/CD20-double-positive cells, and 2 months later, it was followed by a very severe paraneoplastic pemphigus affecting the mucosa and the skin. The lymphoma was well managed with CHOP and CVP polychemotherapy, followed by oral chlorambucil; however, the bullous eruptions did not disappear. Oral steroids, cyclophosphamide, plasmapheresis and IVIG therapy were only partially successful, so we decided to use oral cyclosporin A. Starting with 7 mg/kg and maintaining a steady plasma level of no less then 110 ng/l, the bullae completely disappeared within 6 weeks, and the patient has been in remission for 17 months now, taking the oral cyclosporin A continuously. The underlying B cell disorder did not relapse during the therapy.

Overcoming MDR by ultrasound-induced hyperthermia and P-glycoprotein modulation

We assessed the effects of combining ultrasound-induced hyperthermia (USHT) with the P-glycoprotein modulator PSC 833 on cellular retention and cytotoxicity of rhodamine 123 (R123) and doxorubicin in the parent and multidrug resistance (MDR) variants of two human cancer lines. USHT significantly increased cellular uptake of R123 and doxorubicin. Without PSC 833, release of R123 and doxorubicin from both USHT-treated and untreated cells was rapid. As expected, PSC 833 (0.5 microM) only slowed their release into the MDR lines. Interestingly, despite the differences in their starting amounts, PSC 833 was effective in prolonging R123 and doxorubicin release from both USHT-treated and untreated MDR cells. PSC 833 did not augment the cytotoxicity of doxorubicin in parent lines but did cause a significant increase in cytotoxicity of doxorubicin in the MDR lines. However, the combined effect of USHT and PSC 833 on cytotoxicity of doxorubicin far exceeded that produced by USHT or PSC 833 alone.

Cyclosporin A for the treatment of cytopenia associated with chronic lymphocytic leukemia

BACKGROUND

Autoimmune cytopenias are a frequent complication in patients with chronic lymphocytic leukemia (CLL). Anecdotal reports suggest that cyclosporin A (CsA) may be beneficial for patients with CLL-associated pure red cell aplasia. In the current study, the authors investigated the use of CsA in the management of anemia or thrombocytopenia of presumed autoimmune etiology associated with CLL.

METHODS

Thirty-one patients with CLL and anemia or thrombocytopenia of presumed autoimmune etiology were treated with CsA at a dose of 300 mg/day. Sixteen patients (52%) had anemia (hemoglobin <or= 11 g/dL) and 29 patients (94%) had thrombocytopenia (platelet count <or= 100 x 10(9)/L). Seventeen patients (55%) had cytopenia that developed during the course of treatment with fludarabine-based regimens. Nineteen patients (61%) had received prior therapy for this complication using steroids, intravenous immunoglobulin, and/or splenectomy.

RESULTS

Eighteen patients (62%) with thrombocytopenia and 10 patients (63%) with anemia had a major response defined as an increase in the platelet count >or= 50 x 10(9)/L or an increase in hemoglobin >or= 3 g/dL. The median time to initial response was 3 weeks (range, 1-13 weeks) and the median time to best response was 10.5 weeks (range, 1-48 weeks). The median duration of response was 10 months (range, 1+-39+ months). Three patients with fludarabine-associated cytopenias were able to receive further therapy with fludarabine with a lesser decrease in the platelet count. A modest decrease in the tumor burden was observed in six patients. The most common toxicity was <or= Grade 2 (according to the National Cancer Institute's Common Toxicity Criteria) elevation of creatinine, which was observed in 6 patients (19%). Three patients developed opportunistic infections.

CONCLUSIONS

CsA is an effective alternative for the treatment of anemia or thrombocytopenia of suspected autoimmune etiology, including those cases occurring in the course of treatment with fludarabine. A modest antileukemic effect was observed in some patients.

Acute myeloid leukemia in the elderly: results of an individualized approach in two centres

We retrospectively assessed seventy-four consecutive patients with AML over 65 years of age (median 71; range 65-88) treated with an individualized approach in two specialized cancer centers. Patients were managed according to their performance status (PS) and associated diseases in both institutions. The proportion of patients with poor PS (3-4) was higher in center 1 (37%) than in center 2 (10%) and in center 1 palliative treatment was given more frequently (16/32 patients) than in center 2 (7/42 patients). Fifty-one patients received intensive combination chemotherapy including an anthracycline and ara-C or VP16 (2 patients) and 36 patients received a second intensive course as reinduction or as consolidation treatment after complete remission. Patients not eligible for myelosuppressive chemotherapy were treated with palliative measures (23 patients). With intensive chemotherapy, complete remission (CR) was achieved in 29 of 51 patients (57%), after first (20 patients) or second course (9 patients) and the rate of deaths during induction was 14% (7 patients). The CR rate was lower for patients with performance status >or= 2 (48%) as compared to patients with performance status <or= 1 (78%) and for patients with secondary AML (46%) as compared to patients with de novo AML (60%). Median survival was 9.1 months for patients receiving intensive treatment and 1.2 months for patients receiving palliative treatment (P=0.001). In the Cox model for overall survival, treatment with curative intent was associated with longer survival (hazard ratio: 0.33, 95% confidence interval: 0.18-0.58) and poor performance status (PS >or= 2) was associated with reduced survival (hazard ratio: 3.29, 95% confidence interval: 1.75-6.17). Overall 2-years and 5-years survival were 20% and 11% for the patients treated intensively. From this study it appears that an individualized approach of treatment with intensive chemotherapy for selected patients offers a substantial CR rate and an improvement in survival. This analysis also suggests that differences in outcome between single institutions can be explained mainly by referral and selection biases

Relative sensitivity of undifferentiated and cyclic adenosine 3',5'-monophosphate-induced differentiated neuroblastoma cells to cyclosporin A: potential role of beta-amyloid and ubiquitin in neurotoxicity

Cyclosporin A is routinely used in transplant therapy following allogeneic or xenogeneic tissue transplantation to prevent rejection. This immunosuppressive drug is also neurotoxic; however, its mechanisms of action for neurotoxicity are poorly understood. Undifferentiated and cyclic adenosine 3',5'-monophosphate (cAMP)-induced differentiated neuroblastoma (NB) cells were used as an experimental model to study the toxicity of cyclosporin A. Results showed that cyclosporin A promoted the outgrowth of neurites and inhibited the growth of undifferentiated NB cells. When cyclosporin A was added simultaneously with RO20-1724, an inhibitor of cyclic nucleotide phosphodiesterase, or with prostaglandin E1, a stimulator of adenylate cyclase, it markedly enhanced the growth inhibitory and differentiation effects of these cAMP-stimulating agents. In addition, cyclosporin A added to cAMP-induced differentiated NB cells caused dose-dependent degeneration of these cells as evidenced by the vacuolization of cytoplasm and the fragmentation of nuclear and cytoplasmic materials; however, neurites remained intact. Cyclosporin A alone did not alter the intensity of cell immunostaining for ubiquitin or beta-amyloid peptide (amino acids 1-14) (Abeta1-14); however, it enhanced the intensity of staining for both ubiquitin and Abeta in cells that were treated with cAMP-stimulating agents. The intensity of staining of amyloid precursor protein (amino acids 44-63) (APP44-66) did not change in any treated group, suggesting that the increase in Abeta staining is due to increased processing of APP to Abeta. We propose that one of the mechanisms of cyclosporin A-induced neurotoxicity involves increased levels of Abeta and ubiquitin.