The novel NF-κB inhibitor IMD-0354 induces apoptosis in chronic lymphocytic leukemia

Nuclear factor-κB (NF-κB) is an important regulator of cell survival and has been shown to be constitutively active in chronic lymphocytic leukemia (CLL) cells. Recently, a novel NF-κB inhibitor, IMD-0354 (N-(3, 5-bis-trifluoromethyl-phenyl)-5-chloro-2-hydroxy-benzamide), was shown to specifically inhibit the phosphorylation of IκBα by IkB kinases, thus preventing NF-κB release. In this study, we investigated if IMD-0354 can inhibit NF-κB activation and induce apoptosis in CLL cells in vitro. The rate of increase in apoptosis, drug sensitivity and DNA-binding activity of NF-κB were studied using Annexin V stainings, the fluorometric microculture cytotoxicity assay and electrophoretic mobility shift assay, respectively. Finally, the impact of IMD-0354 treatment on the expression of a set of apoptosis-related genes was investigated. The results clearly show that IMD-0354 induced apoptosis (mean 26%, range 8–48%) in CLL cells, independent of immunoglobulin heavy variable (IGHV) gene mutational status, and showed a dose-dependent cytotoxic effect. IMD-0354 treatment also significantly lowered the DNA-binding activity of NF-κB in CLL cells. In addition, we identified differences in expression levels of pro- and antiapoptotic genes following IMD-0354 treatment. In summary, our novel findings show that IMD-0354 can induce apoptosis in CLL cells, and thus merits further investigation as an anticancer agent in vivo

MicroRNA Expression Profiling Identifies Activated B Cell Status in Chronic Lymphocytic Leukemia Cells

Chronic lymphocytic leukemia (CLL) is thought to be a disease of resting lymphocytes. However, recent data suggest that CLL cells may more closely resemble activated B cells. Using microRNA (miRNA) expression profiling of highly-enriched CLL cells from 38 patients and 9 untransformed B cells from normal donors before acute CpG activation and 5 matched B cells after acute CpG activation, we demonstrate an activated B cell status for CLL. Gene set enrichment analysis (GSEA) identified statistically-significant similarities in miRNA expression between activated B cells and CLL cells including upregulation of miR-34a, miR-155, and miR-342-3p and downregulation of miR-103, miR-181a and miR-181b. Additionally, decreased levels of two CLL signature miRNAs miR-29c and miR-223 are associated with ZAP70+ and IgVH unmutated status and with shorter time to first therapy. These data indicate an activated B cell status for CLL cells and suggest that the direction of change of individual miRNAs may predict clinical course in CLL

Stat3 Activates the Receptor Tyrosine Kinase Like Orphan Receptor-1 Gene in Chronic Lymphocytic Leukemia Cells

BACKGROUND: The receptor tyrosine kinase like orphan receptor (ROR)-1 gene is overexpressed in chronic lymphocytic leukemia (CLL). Because Stat3 is constitutively activated in CLL and sequence analysis revealed that the ROR1 promoter harbors gamma-interferon activation sequence-like elements typically activated by Stat3, we hypothesized that Stat3 activates ROR1. METHODOLOGY/PRINCIPAL FINDINGS: Because IL-6 induced Stat3 phosphorylation and upregulated Ror1 protein levels in MM1 cells, we used these cells as a model. We transfected MM1 cells with truncated ROR1 promoter luciferase reporter constructs and found that IL-6 induced luciferase activity of ROR1-195 and upstream constructs. Co-transfection with Stat3 siRNA reduced the IL-6-induced luciferase activity, suggesting that IL-6 induced luciferase activity by activating Stat3. EMSA and the ChIP assay confirmed that Stat3 binds ROR1, and EMSA studies identified two Stat3 binding sites. In CLL cells, EMSA and ChIP studies determined that phosphorylated Stat3 bound to the ROR1 promoter at those two ROR1 promoter sites, and ChIP analysis showed that Stat3 co-immunoprecipitated DNA of STAT3, ROR1, and several Stat3-regulated genes. Finally, like STAT3-siRNA in MM1 cells, STAT3-shRNA downregulated STAT3, ROR1, and STAT3-regulated genes and Stat3 and Ror1 protein levels in CLL cells. CONCLUSION/SIGNIFICANCE: Our data suggest that constitutively activated Stat3 binds to the ROR1 promoter and activates ROR1 in CLL cells

Rel A Is an Independent Biomarker of Clinical Outcome in Chronic Lymphocytic Leukemia

Purpose: We recently demonstrated the biologic importance of the nuclear factor kappa B (NF-κB) subunit Rel A in chronic lymphocytic leukemia (CLL) and hypothesized that Rel A DNA binding would have prognostic significance in this disease. Patients and Methods: Rel A DNA binding was quantified in nuclear extracts derived from 131 unselected CLL patient samples using a quantitative DNA-binding enzyme-linked immunosorbent assay–based method. We then investigated the ability of Rel A to predict for the requirement for treatment and survival and compared our findings with other established prognostic markers. Results: Rel A DNA binding was strongly associated with advanced Binet stage (P < .0001) but did not correlate with immunoglobulin VH (IgVH) mutation status (P = .25), CD38 expression (P = .87), or zeta-chain–associated protein kinase 70 (ZAP-70) expression (P = .55). It was predictive of time to first treatment (P = .02) and time to subsequent treatment (P = .0001). In addition, Rel A was the most predictive marker of survival both from date of diagnosis (hazard ratio [HR], 9.1; P = .01) and date of entry into the study (HR, 3.9; P = .05) and retained prognostic significance in multivariate analysis for both time to first treatment and overall survival in the presence of Binet stage, IgVH mutation status, CD38, and ZAP-70. Conclusion: Rel A is an independent prognostic marker of survival in CLL and seems to have the unique capacity to predict the duration of response to therapy. Prospective assessment of Rel A as a marker of clinical outcome and as a therapeutic target are now warranted

Telomere dysfunction and fusion during the progression of chronic lymphocytic leukemia: evidence for a telomere crisis

We performed single-molecule telomere length and telomere fusion analysis in patients at different stages of chronic lymphocytic leukaemia (CLL). Our work identified the shortest telomeres ever recorded in primary human tissue reinforcing the concept that there is significant cell division in CLL. Furthermore, we provide direct evidence that critical telomere shortening, dysfunction and fusion contribute to disease progression. The frequency of short telomeres and fusion events increased with advanced disease, but importantly these were also found in a subset of early-stage patient samples indicating that these events can precede disease progression. Sequence analysis of fusion events isolated from individuals with the shortest telomeres revealed limited numbers of repeats at the breakpoint, sub-telomeric deletion and microhomology. Array-CGH analysis of individuals displaying evidence of telomere dysfunction revealed large-scale genomic rearrangements that were concentrated in the telomeric regions; this was not observed in samples with longer telomeres. The telomere dynamics observed in CLL B-cells were indistinguishable from that observed in cells undergoing crisis in culture following abrogation of the p53 pathway. Taken together our data support the concept that telomere erosion and subsequent telomere fusion is critical in the progression of CLL, and that this paradigm may extend to other malignancies

Highly purified CD38+sub-populations show no evidence of preferential clonal evolution despite having increased proliferative activity when compared with CD38−sub-populations derived from the same chronic lymphocytic leukaemia patient

In agreement with a recently published manuscript, this present study demonstrated that CD38+ sub-populations had increased proliferative activity as evidenced by higher Ki-67 expression (P < 0.0001). This raised the possibility that the CD38+ fraction is exposed to an increased risk of clonal evolution. However, serial fluorescence in situ hybridisation analysis of highly purified CD38+ and CD38- sub-populations from individual patients revealed no distinct cytogenetic lesions or evidence of preferential clonal evolution in the CD38+ fractions when compared with their CD38- counterparts (P = 0Æ13). Furthermore, telomere length analysis revealed that all of the sub-populations had similarly short telomeres (P = 0.31) and comparably low telomerase (TERT) expression (P = 0.75) and telomerase activity(P = 0.88). Subsequent examination of cell-sorted CD38+ and CD38- subpopulations from paired peripheral blood and bone marrow samples taken on the same day showed no significant difference in CD38, Ki-67, TERT expression or telomere lengths, indicating that these chronic lymphocytic leukaemia cells were derived from a single pool trafficking between these two compartments. Taken together, our data show that chronic lymphocytic leukaemia cells derived from bimodal patients all have extensive proliferative histories and have undergone a similar number of cell divisions that is mirrored by the episodic expression of CD38

Multicentric Castleman disease of hyaline vascular variant presenting with unusual systemic manifestations: a case report

Abstract Background Castleman disease is a rare lymphoproliferative disorder presenting with localized or disseminated lymphadenopathy and systemic manifestations. It can be categorized in numerous ways, such as unicentric versus multicentric, histopathological variants (hyaline-vascular, plasma cell, and mixed), or subtypes based on causative viral infections (human immunodeficiency virus, human herpesvirus-8, or Kaposi sarcoma herpesvirus). Presentation ranges from asymptomatic to symptoms involving multiple organs. Even though the exact mechanism of pathogenesis is unknown, treatment is directed toward possible etiologies such as interleukin-6, cluster of differentiation 20, and viral agents. Case presentation A 36-year-old Sri Lankan woman presented with generalized body swelling and foamy urine of 2 weeks’ duration. Examination revealed pallor; generalized edema; axillary, cervical, and inguinal lymphadenopathy; hypertension; and hepatomegaly. Investigations showed bicytopenia, nephrotic range proteinuria with hypoalbuminemia, hypogammaglobulinemia, and features of hyaline-vascular type Castleman disease in a lymph node biopsy. She was managed with rituximab and had good clinical improvement. Conclusions Castleman disease has a broad spectrum of clinical manifestations, disease pathogeneses, and associations and/or complications. Medical professionals need to be familiar with this spectrum because timely diagnosis and aggressive targeted therapy are the cornerstones of managing these patients

The NF- B subunit Rel A is associated with in vitro survival and clinical disease progression in chronic lymphocytic leukemia and represents a promising therapeutic target

In this study, we characterized nuclear factor κB (NF-κB) subunit DNA binding in chronic lymphocytic leukemia (CLL) samples and demonstrated heterogeneity in basal and inducible NF-κB. However, all cases showed higher basal NF-κB than normal B cells. Subunit analysis revealed DNA binding of p50, Rel A, and c-Rel in primary CLL cells, and Rel A DNA binding was associated with in vitro survival (P = .01) with high white cell count (P = .01) and shorter lymphocyte doubling time (P = .01). NF-κB induction after in vitro stimulation with anti-IgM was associated with increased in vitro survival (P < .001) and expression of the signaling molecule ZAP-70 (P = .003). Prompted by these data, we evaluated the novel parthenolide analog, LC-1, in 54 CLL patient samples. LC-1 induced apoptosis in all the samples tested with a mean LD50 of 2.8 μM after 24 hours; normal B and T cells were significantly more resistant to its apoptotic effects (P < .001). Apoptosis was preceded by a marked loss of NF-κB DNA binding and sensitivity to LC-1 correlated with basal Rel A DNA binding (P = .03, r2 = 0.15). Furthermore, Rel A DNA binding was inversely correlated with sensitivity to fludarabine (P = .001, r2 = 0.3), implicating Rel A in fludarabine resistance. Taken together, these data indicate that Rel A represents an excellent therapeutic target for this incurable disease