Crizotinib in Combination with Everolimus Synergistically Inhibits Proliferation of Anaplastic Lymphoma Kinase‒Positive Anaplastic Large Cell Lymphoma.

PURPOSE: Anaplastic large cell lymphoma (ALCL) is a rare aggresive non-Hodgkin lymphoma, of which over 50% of cases have an aberrant nucleophosmin (NPM)‒anaplastic lymphoma kinase (ALK) fusion protein. Both mechanistic target of rapamycin (mTOR) inhibitor everolimus and ALK inhibitor crizotinib have shown promising antitumor activity in ALK-positive cancer cell lines. However, their combined effect has not yet been investigated. MATERIALS AND METHODS: We evaluated the anti-proliferative effects of everolimus and/or crizotinib in ALK-positive ALCL cell lines, Karpas 299 and SU-DHL-1, and lung adenocarcinoma cell line, NCI-H2228. RESULTS: We found that individually, both everolimus and crizotinib potently inhibited cell growth in a dose-dependent manner in both Karpas 299 and SU-DHL-1 cells. A combination of these agents synergistically inhibited proliferation in the two cell lines. Crizotinib down-regulated aberrant AKT and ERK phosphorylation induced by everolimus. Combination treatment also significantly increased G0/G1 cell-cycle arrest, DNA damage, and apoptosis compared with everolimus or crizotinib alone in ALK-positive ALCL cells. In the Karpas 299 xenograft model, the combination treatment exerted a stronger antitumor effect than monotherapies, without significant change in body weight. The synergistic effect of everolimus and crizotinib was also reproduced in the ALK-positive lung adenocarcinoma cell line NCI-H2228. The combination treatment abrogated phosphoinositide 3-kinase/AKT and mTOR signaling pathways with little effect on the Ras/ERK pathway in NCI-H2228 cells. CONCLUSION: Crizotinib combinedwith everolimus synergistically inhibits proliferation of ALK-positive ALCL cells. Our results suggest that this novel combination is worthy of further clinical development in patients with ALK-positive ALCL.

A scientific treatment approach for acute mast cell leukemia: using a strategy based on next-generation sequencing data.

BACKGROUND: Mast cell leukemia (MCL) is the most aggressive form of systemic mastocytosis disorders. Owing to its rarity, neither pathogenesis nor standard treatment is established for this orphan disease. Hence, we tried to treat a patient with MCL based on the exome and transcriptome sequencing results of the patient's own DNA and RNA. METHODS: First, tumor DNA and RNA were extracted from bone marrow at the time of diagnosis. Germline DNA was extracted from the patient's saliva 45 days after induction chemotherapy and used as a control. Then, we performed whole-exome sequencing (WES) using the DNA and whole transcriptome sequencing (WTS) using the RNA. Single nucleotide variants (SNVs) were called using MuTect and GATK. Samtools, FusionMap, and Gene Set Enrichment Analysis were utilized to analyze WTS results. RESULTS: WES and WTS results revealed mutation in KIT S476I. Fusion analysis was performed using WTS data, which suggested a possible RARα-B2M fusion. When RNA expression analysis was performed using WTS data, upregulation of PIK3/AKT pathway, downstream of KIT and mTOR, was observed. Based on our WES and WTS results, we first administered all-trans retinoic acid, then dasatinib, and finally, an mTOR inhibitor. CONCLUSION: We present a case of orphan disease where we used a targeted approach using WES and WTS data of the patient. Even though our treatment was not successful, use of our approach warrants further validation.

Revealing Genomic Profile That Underlies Tropism of Myeloma Cells Using Whole Exome Sequencing.

Background. Previously we established two cell lines (SNU_MM1393_BM and SNU_MM1393_SC) from different tissues (bone marrow and subcutis) of mice which were injected with single patient's myeloma sample. We tried to define genetic changes specific for each cell line using whole exome sequencing (WES). Materials and Methods. We extracted DNA from SNU_MM1393_BM and SNU_MM1393_SC and performed WES. For single nucleotide variants (SNV) calling, we used Varscan2. Annotation of mutation was performed using ANNOVAR. Results. When calling of somatic mutations was performed, 68 genes were nonsynonymously mutated only in SNU_MM1393_SC, while 136 genes were nonsynonymously mutated only in SNU_MM1393_BM. KIAA1199, FRY, AP3B2, and OPTC were representative genes specifically mutated in SNU_MM1393_SC. When comparison analysis was performed using TCGA data, mutational pattern of SNU_MM1393_SC resembled that of melanoma mostly. Pathway analysis using KEGG database showed that mutated genes specific of SNU_MM1393_BM were related to differentiation, while those of SNU_MM1393_SC were related to tumorigenesis. Conclusion. We found out genetic changes that underlie tropism of myeloma cells using WES. Genetic signature of cutaneous plasmacytoma shares that of melanoma implying common mechanism for skin tropism. KIAA1199, FRY, AP3B2, and OPTC are candidate genes for skin tropism of cancers.

Establishment of cell lines from both myeloma bone marrow and plasmacytoma: SNU_MM1393_BM and SNU_MM1393_SC from a single patient.

PURPOSE: We tried to establish clinically relevant human myeloma cell lines that can contribute to the understanding of multiple myeloma (MM). MATERIALS AND METHODS: Mononuclear cells obtained from MM patient's bone marrow were injected via tail vein in an NRG/SCID mouse. Fourteen weeks after the injection, tumor developed at subcutis of the mouse. The engraftment of MM cells into mouse bone marrow (BM) was also observed. We separated and cultured cells from subcutis and BM. RESULTS: After the separation and culture of cells from subcutis and BM, we established two cell lines originating from a single patient (SNU_MM1393_BM and SNU_MM1393_SC). Karyotype of the two newly established MM cell lines showed tetraploidy which is different from the karyotype of the patient (diploidy) indicating clonal evolution. In contrast to SNU_MM1393_BM, cell proliferation of SNU_MM1393_SC was IL-6 independent. SNU_MM1393_BM and SNU_MM1393_SC showed high degree of resistance against bortezomib compared to U266 cell line. SNU_MM1393_BM had the greater lethality compared to SNU_MM1393_SC. CONCLUSION: Two cell lines harboring different site tropisms established from a single patient showed differences in cytokine response and lethality. Our newly established cell lines could be used as a tool to understand the biology of multiple myeloma.

Establishment and characterization of bortezomib-resistant U266 cell line: constitutive activation of NF-κB-mediated cell signals and/or alterations of ubiquitylation-related genes reduce bortezomib-induced apoptosis.

Bortezomib has been known as the most promising anti-cancer drug for multiple myeloma (MM). However, recent studies reported that not all MM patients respond to bortezomib. To overcome such a stumbling-block, studies are needed to clarify the mechanisms of bortezomib resistance. In this study, we established a bortezomib-resistant cell line (U266/velR), and explored its biological characteristics. The U266/velR showed reduced sensitivity to bortezomib, and also showed crossresistance to the chemically unrelated drug thalidomide. U266/velR cells had a higher proportion of CD138 negative subpopulation, known as stem-like feature, compared to parental U266 cells. U266/velR showed relatively less inhibitory effect of prosurvival NF-κB signaling by bortezomib. Further analysis of RNA microarray identified genes related to ubiquitination that were differentially regulated in U266/velR. Moreover, the expression level of CD52 in U266 cells was associated with bortezomib response. Our findings provide the basis for developing therapeutic strategies in bortezomib-resistant relapsed and refractory MM patients.

TNF α mediated IL-6 secretion is regulated by JAK/STAT pathway but not by MEK phosphorylation and AKT phosphorylation in U266 multiple myeloma cells.

IL-6 and TNF α were significantly increased in the bone marrow aspirate samples of patients with active multiple myeloma (MM) compared to those of normal controls. Furthermore, MM patients with advanced aggressive disease had significantly higher levels of IL-6 and TNF α than those with MM in plateau phase. TNF α increased interleukin-6 (IL-6) production from MM cells. However, the detailed mechanisms involved in signaling pathways by which TNF α promotes IL-6 secretion from MM cells are largely unknown. In our study, we found that TNF α treatments induce MEK and AKT phosphorylation. TNF α -stimulated IL-6 production was abolished by inhibition of JAK2 and IKK ß or by small interfering RNA (siRNA) targeting TNF receptors (TNFR) but not by MEK, p38, and PI3K inhibitors. Also, TNF α increased phosphorylation of STAT3 (ser727) including c-Myc and cyclin D1. Three different types of JAK inhibitors decreased the activation of the previously mentioned pathways. In conclusion, blockage of JAK/STAT-mediated NF- κ B activation was highly effective in controlling the growth of MM cells and, consequently, an inhibitor of TNF α -mediated IL-6 secretion would be a potential new therapeutic agent for patients with multiple myeloma.