sirolimus and Lymphoma--Large-Cell--Anaplastic

The prognosis of relapsed or refractory aggressive lymphoma is poor. The huge variety of currently evolving targeted treatment approaches would benefit from tools for early prediction of response or resistance. We used various ALK-positive anaplastic large cell lymphoma (ALCL) cell lines to evaluate two inhibitors, the HSP90 inhibitor NVP-AUY922, and the mTOR inhibitor everolimus, both of which have shown to interfere with ALK-dependent oncogenic signal transduction. Their therapeutic effect was determined in vitro by MTT assay, [(18)F]fluorodeoxyglucose (FDG)- and [(18)F]fluorothymidine (FLT)-uptake, and by biochemical analysis of ALK-induced signaling. Micro-FDG- and FLT-positron emission tomography (PET) imaging studies in immunodeficient mice bearing ALCL xenotransplants were carried out with the cell lines SUDHL-1 and Karpas299 to assess early treatment response to NVP-AUY922 or everolimus in vivo. SUDHL-1 cells showed sensitivity to both inhibitors in vitro. Importantly, we detected a significant reduction of FLT-uptake in SUDHL-1 bearing animals using both inhibitors compared with baseline as early as 5 days after initiation of targeted therapy. Immunostaining showed a decrease in Ki-67 and an increase in cleaved caspase-3 staining. In contrast, FDG-uptake did not significantly decrease at early time points. Karpas299 xenotransplants, which are resistant to NVP-AUY922 and sensitive to everolimus treatment, showed an increase of mean FLT-uptake on day 2 after administration of NVP-AUY299, but a significant reduction in FLT-uptake upon everolimus treatment. In conclusion, we show that FLT-PET but not FDG-PET is able to predict response to treatment with specific inhibitors very early in the course of treatment and thus enables early prediction of treatment efficacy.

Topics: Animals; Blotting, Western; Cell Line; Cell Line, Tumor; Cell Survival; Dideoxynucleosides; Enzyme Inhibitors; Everolimus; Female; Flow Cytometry; Fluorine Radioisotopes; Fluorodeoxyglucose F18; HSP90 Heat-Shock Proteins; Humans; Isoxazoles; Lymphoma, Large-Cell, Anaplastic; Mice; Mice, SCID; Positron-Emission Tomography; Protein-Tyrosine Kinases; Resorcinols; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Tumor Burden; Xenograft Model Antitumor Assays

Aberrant anaplastic lymphoma kinase (ALK) expression is a defining feature of many human cancers and was identified first in anaplastic large-cell lymphoma (ALCL), an aggressive non-Hodgkin T-cell lymphoma. Since that time, many studies have set out to identify the mechanisms used by aberrant ALK toward tumorigenesis. We have identified a distinct profile of micro-RNAs (miRNAs) that characterize ALCL; furthermore, this profile distinguishes ALK(+) from ALK(-) subtypes, and thus points toward potential mechanisms of tumorigenesis induced by aberrant ALK. Using a nucleophosmin-ALK transgenic mouse model as well as human primary ALCL tumor tissues and human ALCL-derived cell lines, we reveal a set of overlapping deregulated miRNAs that might be implicated in the development and progression of ALCL. Importantly, ALK(+) and ALK(-) ALCL could be distinguished by a distinct profile of "oncomirs": Five members of the miR-17-92 cluster were expressed more highly in ALK(+) ALCL, whereas miR-155 was expressed more than 10-fold higher in ALK(-) ALCL. Moreover, miR-101 was down-regulated in all ALCL model systems, but its forced expression attenuated cell proliferation only in ALK(+) and not in ALK(-) cell lines, perhaps suggesting different modes of ALK-dependent regulation of its target proteins. Furthermore, inhibition of mTOR, which is targeted by miR-101, led to reduced tumor growth in engrafted ALCL mouse models. In addition to future therapeutical and diagnostic applications, it will be of interest to study the physiological implications and prognostic value of the identified miRNA profiles.

Topics: Anaplastic Lymphoma Kinase; Animals; Antineoplastic Agents; Base Sequence; Cell Line, Tumor; Cell Proliferation; Gene Expression Profiling; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Lymphoma, Large-Cell, Anaplastic; Mice; Mice, Transgenic; MicroRNAs; Multigene Family; Protein-Tyrosine Kinases; Receptor Protein-Tyrosine Kinases; Sirolimus; Xenograft Model Antitumor Assays

Topics: Adult; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Kidney Function Tests; Lymphoma, Large-Cell, Anaplastic; Male; Proteinuria; Sirolimus; Transplantation, Homologous

Recurrent chromosomal aberrations in hematopoietic tumors target genes involved in pathogenesis. Their identification and functional characterization are therefore important for the establishment of rational therapies. Here, we investigated genomic amplification at 7q22 in the T-cell lymphoma cell line SU-DHL-1 belonging to the subtype of anaplastic large-cell lymphoma (ALCL). Cytogenetic analysis mapped this amplicon to 86-95 Mb. Copy-number determination quantified the amplification level at 5- to 6-fold. Expression analysis of genes located within this region identified cyclin-dependent kinase 6 (CDK6) as a potential amplification target. In comparison with control cell lines, SU-DHL-1 expressed considerably higher levels of CDK6. Functionally, SU-DHL-1 cells exhibited reduced sensitivity to rapamycin treatment, as indicated by cell growth and cell cycle analysis. Rapamycin reportedly inhibits degradation of the CDK inhibitor p27 with concomitant downregulation of cyclin D3, implying a proliferative advantage for CDK6 overexpression. Amplification of the CDK6 locus was analyzed in primary T-cell lymphoma samples and, while detected infrequently in those classified as ALCL (1%), was detected in 23% of peripheral T-cell lymphomas not otherwise specified. Taken together, analysis of the 7q22 amplicon identified CDK6 as an important cell cycle regulator in T-cell lymphomas, representing a novel potential target for rational therapy.

Topics: Cell Line, Tumor; Chromosome Aberrations; Chromosomes, Human, Pair 7; Cyclin-Dependent Kinase 6; Cytogenetic Analysis; Drug Resistance; Gene Dosage; Gene Expression Regulation, Neoplastic; Humans; Lymphoma, Large-Cell, Anaplastic; Lymphoma, T-Cell; Lymphoma, T-Cell, Peripheral; Sirolimus; Tumor Cells, Cultured

Topics: Aged; Female; Humans; Lymphoma, Large-Cell, Anaplastic; Protein Kinase Inhibitors; Protein Kinases; Salvage Therapy; Sirolimus; Skin Neoplasms; TOR Serine-Threonine Kinases; Treatment Outcome