CD40 induces apoptosis in carcinoma cells through activation of cytotoxic ligands of the tumor necrosis factor superfamily.

CD40, a tumor necrosis factor (TNF) receptor (TNFR) family member, conveys signals regulating diverse cellular responses, ranging from proliferation and differentiation to growth suppression and cell death. The ability of CD40 to mediate apoptosis in carcinoma cells is intriguing given the fact that the CD40 cytoplasmic C terminus lacks a death domain homology with the cytotoxic members of the TNFR superfamily, such as Fas, TNFR1, and TNF-related apoptosis-inducing ligand (TRAIL) receptors. In this study, we have probed the mechanism by which CD40 transduces death signals. Using a trimeric recombinant soluble CD40 ligand to activate CD40, we have found that this phenomenon critically depends on the membrane proximal domain (amino acids 216 to 239) but not the TNFR-associated factor-interacting PXQXT motif in the CD40 cytoplasmic tail. CD40-mediated cytotoxicity is blocked by caspase inhibitors, such as zVAD-fmk and crmA, and involves activation of caspase 8 and caspase 3. Interestingly, CD40 ligation was found to induce functional Fas ligand, TRAIL (Apo-2L) and TNF in apoptosis-susceptible carcinoma cells and to up-regulate expression of Fas. These findings identify a novel proapoptotic mechanism which is induced by CD40 in carcinoma cells and depends on the endogenous production of cytotoxic cytokines and autocrine or paracrine induction of cell death.

Nilotinib in patients with Ph+ chronic myeloid leukemia in accelerated phase following imatinib resistance or intolerance: 24-month follow-up results.

Nilotinib (Tasigna) is a potent and selective BCR-ABL inhibitor approved for use in patients with newly diagnosed chronic myeloid leukemia (CML) in chronic phase (CML-CP) and in patients with CML-CP and accelerated phase (CML-AP) who are resistant to or intolerant of imatinib. Patients with CML-AP (N = 137) with at least 24 months of follow-up or who discontinued early were evaluated to determine the efficacy and tolerability of nilotinib. The majority (55%) of patients achieved a confirmed hematologic response, and 31% attained a confirmed complete hematologic response on nilotinib treatment. Overall, 32% of patients achieved major cytogenetic responses (MCyR), with most being complete cytogenetic responses. Responses were durable, with 66% of patients maintaining MCyR at 24 months. The estimated overall and progression-free survival rates at 24 months were 70% and 33%, respectively. Grade 3/4 neutropenia and thrombocytopenia were each observed in 42% of patients. Non-hematologic adverse events were mostly mild to moderate; the safety profile of nilotinib has not changed with longer follow-up. In all, 20 (15%) patients remained on study at data cutoff. In summary, nilotinib has a manageable safety profile, and can provide favorable long-term outcomes in the pretreated CML-AP patient population for whom treatment options are limited.

Nilotinib vs imatinib in patients with newly diagnosed Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase: ENESTnd 3-year follow-up.

Evaluating Nilotinib Efficacy and Safety in Clinical Trials Newly Diagnosed Patients compares nilotinib and imatinib in patients with newly diagnosed chronic myeloid leukemia in chronic phase (CML-CP). With a minimum follow-up of 3 years, major molecular response, molecular response of BCR-ABL≤ 0.01% expressed on the international scale (BCR-ABL(IS); MR(4)) and BCR-ABL(IS)≤ 0.0032% (MR(4.5)) rates were significantly higher with nilotinib compared with imatinib, and differences in the depth of molecular response between nilotinib and imatinib have increased over time. No new progressions occurred on treatment since the 2-year analysis. Nilotinib was associated with a significantly lower probability of progression to accelerated phase/blast crisis vs imatinib (two (0.7%) progressions on nilotinib 300 mg twice daily, three (1.1%) on nilotinib 400 mg twice daily and 12 (4.2%) on imatinib). When considering progressions occurring after study treatment discontinuation, the advantage of nilotinib over imatinib in preventing progression remained significant (nine (3.2%) progressions on nilotinib 300 mg twice daily, six (2.1%) on nilotinib 400 mg twice daily and 19 (6.7%) on imatinib). Both nilotinib and imatinib were well tolerated, with minimal changes in safety over time. Nilotinib continues to demonstrate superior efficacy in all key response and outcome parameters compared with imatinib for the treatment of patients with newly diagnosed CML-CP.

Nilotinib is effective in imatinib-resistant or -intolerant patients with chronic myeloid leukemia in blastic phase.

Nilotinib is a selective inhibitor of BCR-ABL approved for use in newly diagnosed and imatinib-resistant or -intolerant patients with chronic myeloid leukemia (CML) in chronic phase. In this study, 400 mg of nilotinib was administered twice daily to the patients with myeloid (MBP, n=105) or lymphoid blastic phase (LBP, n=31) CML. After a minimum follow-up of 24 months, major hematologic responses were observed in 60% (MBP) and 59% (LBP) of patients. Major cytogenetic responses (MCyR) were attained in 38% (MBP) and 52% (LBP) of patients; and complete cytogenetic responses in 30% and 32%, respectively. Median duration of MCyR was 10.8 (MBP) and 3.2 months (LBP). Median overall survival was 10.1 (MBP) and 7.9 (LBP) months with 12- and 24-month survival of 42% (MBP 44%, LBP 35%) and 27% (MBP 32%, LBP 10%), respectively. Twelve MBP patients and two LBP patients received subsequent stem cell transplantation. Myelosuppression was frequent, with grade 3/4 neutropenia, thrombocytopenia, and anemia in 68%, 63% and 47% of patients, respectively. Grade 3/4 hypophosphatemia, hyperbilirubinemia and lipase elevation were observed in 15%, 11% and 11% of patients, respectively. Nilotinib has significant efficacy in patients with BP CML, but given the limited long-term survival of these patients, novel agents are needed.

Nilotinib is active in chronic and accelerated phase chronic myeloid leukemia following failure of imatinib and dasatinib therapy.

Nilotinib is a highly selective Bcr-Abl inhibitor approved for imatinib-resistant chronic myeloid leukemia (CML). Nilotinib and dasatinib, a multi-targeted kinase inhibitor also approved for second-line therapy in CML, have different patterns of kinase selectivity, pharmacokinetics, and cell uptake and efflux properties, and thus patients may respond to one following failure of the other. An international phase II study of nilotinib was conducted in CML patients (39 chronic phase (CP), 21 accelerated phase (AP)) after failure of both imatinib and dasatinib. Median times from diagnosis of CP or AP to nilotinib therapy were 89 and 83 months, respectively. Complete hematological response and major cytogenetic response (MCyR) rates in CP were 79% and 43%, respectively. Of 17 evaluable patients with CML-AP, 5 (29%) had a confirmed hematological response and 2 (12%) a MCyR. The median time to progression has not yet been reached in CP patients. At 18 months 59% of patients were progression-free. Median overall survival for both populations has not been reached, and the estimated 18-month survival rate in CML-CP was 86% and that at 12 months for CML-AP was 80%. Nilotinib is an effective therapy in CML-CP and -AP following failure of both imatinib and dasatinib therapy.

CD40 and epithelial cells: across the great divide.

The widespread expression of CD40 in normal epithelial cells and carcinoma cells suggests that this receptor has important, additional influences beyond that of regulating immune responses. Here, Lawrence Young and colleagues discuss the effect of CD40 ligation on epithelial cells and consider the role of this pathway in the pathogenesis and treatment of carcinomas.

Activation of the p38 mitogen-activated protein kinase pathway by Epstein-Barr virus-encoded latent membrane protein 1 coregulates interleukin-6 and interleukin-8 production.

The Epstein-Barr virus-encoded latent membrane protein 1 (LMP1) is a pleiotropic protein the activities of which include effects on gene expression and cell transformation, growth, and death. LMP1 has been shown to induce nuclear factor (NF)-kappaB and c-Jun NH2-terminal kinase/AP-1 activities in target cells, and in this study we demonstrate that LMP1 also engages the p38 mitogen-activated protein kinase cascade, leading to activation of the transcription factor ATF2. Mutational analysis of the LMP1 cytoplasmic COOH terminus revealed that p38 activation occurs from both the tumor necrosis factor receptor-associated factor (TRAF)-interacting, membrane-proximal COOH-terminal activating region (CTAR)1 domain (amino acids 186-231) and the extreme tumor necrosis factor receptor-associated death domain (TRADD) binding CTAR2 region (amino acids 351-386). Because LMP1 also engages signaling on the NF-kappaB axis through CTAR1 and CTAR2, we have examined whether these two pathways are overlapping or independent. We have found that inhibition of p38 by the highly specific inhibitor SB203580 did not affect NF-kappaB binding activity. Conversely, although the metabolic inhibitor D609 blocked NF-kappaB activation, it did not impair the ability of LMP1 to signal on the p38 axis, suggesting that these two LMP1-mediated pathways are primarily independent. Divergence of signals must, however, occur downstream of TRAF2 as a dominant negative TRAF2 mutant that blocks LMP1-induced NF-kappaB activation also inhibited p38 signaling. In addition, we have found that p38 inhibition significantly impaired LMP1-mediated interleukin-6 and -8 expression. Thus, p38 may play a significant cooperative role in regulating at least some of the pleiotropic activities of LMP1.

CD40 activation in epithelial ovarian carcinoma cells modulates growth, apoptosis, and cytokine secretion.

BACKGROUND/AIMS: CD40, a member of the tumour necrosis factor (TNF) receptor family, is expressed on a variety of haematopoietic cells and is crucial in orchestrating both humoral and cellular immune responses. CD40 is also expressed on some carcinoma cells, where its function remains largely unknown. This study investigated the effects of CD40 ligation on ovarian carcinoma cell growth and apoptosis and on cytokine production, in addition to the role of the NF-kappa B and JNK signalling pathways. METHODS: CD40 expression was measured in epithelial ovarian carcinoma (EOC) biopsies by immunohistochemistry and in EOC cell lines by flow cytometry. To examine the effects of CD40 ligation on cell growth recombinant soluble CD40 ligand was used to stimulate EOC cell lines and growth was measured by MMT assays. Cytokine production was measured by enzyme linked immunosorbent assays interleukin 8 (IL-8) gene transcription was estimated by means of reverse transcription polymerase chain reaction. The integrity of the CD40 signalling pathway in those cell lines that did not produce cytokines in response to CD40 ligation was assessed by the detection of the transcription factor NF-kappa B by an electrophoretic mobility shift assay. To investigate the defect in the NF-kappa B pathway the phosphorylation status of I kappa B alpha was determined by an antibody specific to phosphorylated I kappa B alpha and dissociation of the I kappa B alpha-p65 complex was assessed by co-immunoprecipitation. RESULTS: CD40 is expressed in primary ovarian carcinoma biopsies and EOC cell lines. CD40 ligation resulted in growth inhibition in most of these carcinoma cell lines and was also found to promote apoptosis, with this last effect only being evident in early passage EOC cells. CD40 ligation also induced significant IL-6 and IL-8 production in most of the EOC cell lines examined and it was confirmed for IL-8 that this effect was regulated at the transcriptional level. NF-kappa B activation in response to CD40 ligation was found in three of the EOC cell lines and specific defects in the CD40 induced NF-kappa B pathway were identified in two cell lines. However, CD40 engagement induced JNK activation in all the EOC cell lines. CONCLUSIONS: These data suggest that the CD40 pathway is functional in ovarian carcinoma cells and highlight the need for further studies to provide insight into the role of CD40 in the carcinogenic process and the possible exploitation of this pathway for novel therapeutic approaches.