Randomized phase III GnG study on two schedules of gemtuzumab ozogamicin as adjunct to intensive induction therapy and double-blinded intensive post-remission therapy with or without glasdegib in patients with newly diagnosed acute myeloid leukemia

Not available.

Age-Related Gliosis Promotes Central Nervous System Lymphoma through CCL19-Mediated Tumor Cell Retention

How lymphoma cells (LCs) invade the brain during the development of central nervous system lymphoma (CNSL) is unclear. We found that NF-κB-induced gliosis promotes CNSL in immunocompetent mice. Gliosis elevated cell-adhesion molecules, which increased LCs in the brain but was insufficient to induce CNSL. Astrocyte-derived CCL19 was required for gliosis-induced CNSL. Deleting CCL19 in mice or CCR7 from LCs abrogated CNSL development. Two-photon microscopy revealed LCs transiently entering normal brain parenchyma. Astrocytic CCL19 enhanced parenchymal CNS retention of LCs, thereby promoting CNSL formation. Aged, gliotic wild-type mice were more susceptible to forming CNSL than young wild-type mice, and astrocytic CCL19 was observed in both human gliosis and CNSL. Therefore, CCL19-CCR7 interactions may underlie an increased age-related risk for CNSL.

Design, synthesis and biological activity of N4-phenylsubstituted-7H-pyrrolo[2,3-d]pyrimidin-4-amines as dual inhibitors of aurora kinase A and epidermal growth factor receptor kinase

Simultaneous inhibition of multiple kinases has been suggested to provide synergistic effects on inhibition of tumour growth and resistance. This study describes the design, synthesis and evaluation of 18 compounds incorporating a pyrrolo[2,3-d]pyrimidine scaffold for dual inhibition of epidermal growth factor receptor kinase (EGFR) and aurora kinase A (AURKA). Compounds 1-18 of this study demonstrate nanomolar inhibition of EGFR and micromolar inhibition of AURKA. Compounds 1-18 allow for a structure-activity relationships (SAR) analysis of the 4-anilino moiety for dual EGFR and AURKA inhibition. Compound 6, a 4-methoxyphenylpyrrolo[2,3-d]pyrimidin-4-amine, demonstrates single-digit micromolar inhibition of both AURKA and EGFR and provides evidence of a single molecule with dual activity against EGFR and AURKA. Compound 2, the most potent inhibitor of EGFR and AURKA from this series, has been further evaluated in four different squamous cell head and neck cancer cell lines for downstream effects resulting from AURKA and EGFR inhibition.

Cks1 is required for tumor cell proliferation but not sufficient to induce hematopoietic malignancies

The Cks1 component of the SCF(Skp2) complex is necessary for p27(Kip1) ubiquitylation and degradation. Cks1 expression is elevated in various B cell malignancies including Burkitt lymphoma and multiple myeloma. We have previously shown that loss of Cks1 results in elevated p27(Kip1) levels and delayed tumor development in a mouse model of Myc-induced B cell lymphoma. Surprisingly, loss of Skp2 in the same mouse model also resulted in elevated p27(Kip1) levels but exhibited no impact on tumor onset. This raises the possibility that Cks1 could have other oncogenic activities than suppressing p27(Kip1). To challenge this notion we have targeted overexpression of Cks1 to B cells using a conditional retroviral bone marrow transduction-transplantation system. Despite potent ectopic overexpression, Cks1 was unable to promote B cell hyperproliferation or B cell malignancies, indicating that Cks1 is not oncogenic when overexpressed in B cells. Since Skp2 overexpression can drive T-cell tumorigenesis or other cancers we also widened the quest for oncogenic activity of Cks1 by ubiquitously expressing Cks1 in hematopoetic progenitors. At variance with c-Myc overexpression, which caused acute myeloid leukemia, Cks1 overexpression did not induce myeloproliferation or leukemia. Therefore, despite being associated with a poor prognosis in various malignancies, sole Cks1 expression is insufficient to induce lymphoma or a myeloproliferative disease in vivo.

Efficacy of repeat myeloablative chemotherapy with autologous stem-cell support in multiple myeloma

OBJECTIVE

Induction high-dose chemotherapy followed by myeloablative melphalan (HD-Mel) treatment and autologous hematopoietic stem-cell support (autoSCT) is a standard treatment for multiple myeloma (MM) either upfront or in relapse after conventional treatment. We performed a retrospective analysis of consecutive patients undergoing a late repeat HD-Mel/autoSCT treatment for MM.

METHODS

Data from 24 consecutive patients with MM who underwent a myeloablative treatment with HD-Mel late after completion of upfront first high-dose therapy were assessed for toxicity, response, progression-free survival (PFS) and time to next treatment (TTNT). These data were correlated with the results obtained after the initial high dose therapy and autoSCT.

RESULTS

A total of 23 patients were treated with novel drugs (lenalidomide, thalidomide, bortezomib) after relapse to initial autoSCT. The median overall survival (OS) of all patients was 90 months. 19 patients (79%) achieved a very good partial remission (VGPR) or complete remission (CR) after initial autoSCT, compared with 42% after late autoSCT. PFS and TTNT were 19 and 24 months after initial compared with 13 and 21 months after late autoSCT. Univariate analysis identified initial response duration and the achievement of a CR/VGPR after the initial transplantation to be associated with prolonged response after repeat autoSCT.

CONCLUSIONS

Our data indicate that late high-dose treatment followed by autoSCT is safe and effective after upfront intensive treatment, can bridge to allogeneic SCT, and encourage collection of an additional graft.

Aurora kinase inhibition overcomes cetuximab resistance in squamous cell cancer of the head and neck

Squamous cell cancer of the head and neck (SCCHN) is the sixth leading cause for cancer deaths worldwide. Despite extense knowledge of risk factors and pathogenesis about 50 percent of all patients and essentially every patient with metastatic SCCHN eventually die from this disease. We analyzed the clinical data and performed immunohistochemistry for Epidermal growth factor receptor (EGFR) and Aurora kinase A (Aurora-A) expression in 180 SCCHN patients. Patients characterized by elevated EGFR and elevated Aurora-A protein expression in tumor tissue represent a risk group with poor disease-free and overall survival (EGFR(low)Aurora-A(low) versus EGFR(high)Aurora-A(high), p = 0.024). Treating SCCHN cell lines with a pan-Aurora kinase inhibitor resulted in defective cytokinesis, polyploidy and apoptosis, which was effective irrespective of the EGFR status. Combined Aurora kinase and EGFR targeting using a monoclonal anti-EGFR antibody was more effective compared to single EGFR and Aurora kinase inhibition. Comparing pan-Aurora kinase and Aurora-A targeting hints towards a strong and clinically relevant biological effect mediated via Aurora kinase B. Taken together, our findings characterize a new poor risk group in SCCHN patients defined by elevated EGFR and Aurora-A protein expression. Our results demonstrate that combined targeting of EGFR and Aurora kinases represents a therapeutic means to activate cell cycle checkpoints and apoptosis in SCCHN.

Skp2 directs Myc-mediated suppression of p27Kip1 yet has modest effects on Myc-driven lymphomagenesis

The universal cyclin-dependent kinase inhibitor p27(Kip1) functions as a tumor suppressor, and reduced levels of p27(Kip1) connote poor prognosis in several human malignancies. p27(Kip1) levels are predominately regulated by ubiquitin-mediated turnover of the protein, which is marked for destruction by the E3 ubiquitin ligase SCF(Skp2) complex following its phosphorylation by the cyclin E-cyclin-dependent kinase 2 complex. Binding of phospho-p27(Kip1) is directed by the Skp2 F-box protein, and this is greatly augmented by its allosteric regulator Cks1. We have established that programmed expression of c-Myc in the B cells of Emu-Myc transgenic mice triggers p27(Kip1) destruction by inducing Cks1, that this response controls Myc-driven proliferation, and that loss of Cks1 markedly delays Myc-induced lymphomagenesis and cancels the dissemination of these tumors. Here, we report that elevated levels of Skp2 are a characteristic of Emu-Myc lymphomas and of human Burkitt lymphoma that bear MYC/Immunoglobulin chromosomal translocations. As expected, Myc-mediated suppression of p27(Kip1) was abolished in Skp2-null Emu-Myc B cells. However, the effect of Skp2 loss on Myc-driven proliferation and lymphomagenesis was surprisingly modest compared with the effects of Cks1 loss. Collectively, these findings suggest that Cks1 targets, in addition to p27(Kip1), are critical for Myc-driven proliferation and tumorigenesis.