Ju- Yoon

Association of interleukin-6 and interleukin-8 with poor prognosis in elderly patients with chronic lymphocytic leukemia.

Abstract In population studies, the relative survival in chronic lymphocytic leukemia (CLL) decreases with age. In this study, we demonstrated in a cohort of 189 patients from a CLL clinic that overall survival was lower in the sub-cohort of patients aged ≥ 70 years, but causes of death were similar for all age groups, being progressive CLL, secondary malignancies and infections. As normal individuals age, the plasma levels of inflammatory cytokines, such as interleukin-6 (IL-6) and IL-8, can increase. In our patients with CLL, IL-6, IL-8 and tumor necrosis factor-α (TNF-α) levels increased with age to a greater degree than in normal individuals, and the levels correlated closely with plasma β2-microglobulin and with one another. In addition, in patients ≥ 70 years, IL-6 was found to be a better prognostic marker than immunoglobulin variable heavy chain gene (IgVH) status. In vitro studies demonstrated that IL-6 and IL-8 could enhance the binding of CLL cells to stromal cells, suggesting that their clinical activity may be mediated through their effects on the microenvironment. Thus, plasma IL-6 is an important prognostic marker for the elderly with CLL, and this study highlights that the utility of prognostic markers may depend on patient age.

Synergistic apoptotic response between valproic acid and fludarabine in chronic lymphocytic leukaemia (CLL) cells involves the lysosomal protease cathepsin B

Fludarabine, a nucleoside analogue, is commonly used in combination with other agents for the treatment of chronic lymphocytic leukaemia (CLL). In previous studies, valproic acid (VPA), an inhibitor of histone deacetylases, combined with fludarabine to synergistically increase apoptotic cell death in CLL cells. In the present study, we found that the combination of fludarabine and VPA decreases the level of the anti-apoptotic proteins Mcl-1 and XIAP in primary CLL cells. Treatment with fludarabine alone, or in combination with VPA, led to the loss of lysosome integrity, and chemical inhibition of the lysosomal protease cathepsin B, using CA074-Me, was sufficient to reduce apoptosis. VPA treatment increased cathepsin B levels and activities in primary CLL cells, thereby priming CLL cells for lysosome-mediated cell death. Six previously treated patients with relapsed CLL were treated with VPA, followed by VPA/fludarabine combination. The combined therapy resulted in reduced lymphocyte count in five out of six and reduced lymph node sizes in four out of six patients. In vivo VPA treatment increased histone-3 acetylation and cathepsin B expression levels. Thus, the synergistic apoptotic response with VPA and fludarabine in CLL is mediated by cathepsin B activation leading to a decrease in the anti-apoptotic proteins.

Abstract 2015: Effect of valproic acid on fludarabine activity in chronic lymphocytic leukemia patients

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Valproic acid (VPA) is a first-generation anti-epileptic drug that has been shown to inhibit proliferation and induce apoptosis in various hematological malignancies, including multiple myeloma and chronic lymphocytic leukemia (CLL). We show here that the mechanism of VPA-induced apoptosis in CLL is associated with activation of the TNF-related apoptosis-inducing ligand (TRAIL) apoptotic pathway in vitro and in vivo. Treatment of leukemic cell lines or primary CLL cells with VPA increased the level of TRAIL receptor 1 (TRAIL-R1), but not TRAIL-R2, and upregulated the TRAIL pathway in vitro, resulting in increased casepase-8 cleavage. Treatment with VPA also induced formation of reactive oxygen species (ROS), and the combined cytotoxicity of VPA and fludarabine was dampened upon co-treatment with a ROS scavenger, N-acetylcysteine. Having shown the effects of VPA in vitro, a phase II clinical trial was initiated at CancerCare Manitoba to determine the activity of VPA in CLL, either when used alone or in combination with fludarabine. Five patients who had received at least one prior therapy with fludarabine have to date been examined. Three out of 5 patients were fludarabine-resistant, as defined as no response to fludarabine or relapse 50% fall in lymphocyte/lymph node size after receiving 5 cycles of the combination. Peripheral blood samples were obtained prior to each treatment cycle, and mononuclear cells were isolated for analysis by immunoblotting and immunocytochemistry. Levels of both histone 3-acetyl and histone 4-acetyl initially increased and then fluctuated during the course of treatment. TRAIL-R1 levels increased during the course of therapy, while no significant changes in TRAIL-R2 levels were observed. Expression of mRNA levels of genes involved in apoptosis was examined in one patient before and 28 days following VPA. There was a global up-regulation of both pro- and anti-apoptotic genes (as categorized by their gene ontology) which likely explains the effect of VPA on fludarabine sensitivity in CLL. In summary, VPA induces hyper-acetylation of histones in CLL and activates the TRAIL apoptotic pathway. While VPA is ineffective as a single agent in CLL, it can sensitize CLL cells to fludarabine and could be used as an adjuvant in fludarabine-based treatment regimens. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2015. doi:10.1158/1538-7445.AM2011-2015

Abstract 4162: The importance of age-related cytokines in chronic lymphocytic leukemia

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Chronic lymphocytic leukemia (CLL) is a disease of the elderly with the median age at diagnosis being 72 years. Prognosis is highly variable with the relative survival progressively worsening after age 65 years. In this study we have evaluated whether the age-related cytokines, IL-6, IL-8 and TNF-alpha, play a role in the poor survival of elderly patients with CLL. The plasma levels and biological effects of the age-related cytokines, IL-6, IL-8 and TNF-alpha, were evaluated in 193 CLL patients of varying ages. Patients were chosen randomly to reflect the age spectrum and sex distribution of the Manitoban CLL population. As predicted from population studies, the survival of patients progressively worsened with age, with the primary causes of death being CLL or one of its complications (infection or second tumors). Cytokine levels were increased in CLL compared to 37 age- and sex-matched controls. A third of patients aged </=65 years had increased IL-6, compared to 10% in patients < 65. A high correlation was found between the plasma levels of these three cytokines with age and Beta2-microglobulin (a measure of tumor burden). The plasma levels of the cytokines also correlated with each other, suggesting they increased in parallel. In contrast, the standard CLL prognostic markers IgVH mutational status, ZAP-70, CD38 and Rai stage did not correlate with cytokine levels or age. Patients with increased IL-6 or IL-8 had a poorer survival than those with normal levels. For IL-6, this difference was more marked for those </=65 years. Furthermore, focusing on older patients, multivariate analysis with backward selection of variables showed IL-6 and Beta2-microlgobulin to be significant predictors of survival, while the mutational status and Rai stage were not significant. The cause of death was due to CLL-related causes and not to frailty or cardiovascular disease. However, increased cytokine levels correlated with a higher lifetime incidence of cardiovascular disease. Thus, one source of cytokines may be cardiovascular disease, although CLL cells also secreted low amounts of IL-6 and IL-8. The two cytokines, in turn, significantly increased the adhesion of leukemic cells to stromal cells, suggesting that these cytokines may influence the microenvironment, which would contribute to poor survival. In summary, IL-6 and IL-8 are predictors of survival in CLL, where IL-6 is a stronger predictor of survival in older patients than mutational status or Rai stage. Importance of IL-6 and IL-8 may be associated with their role in facilitating the leukemic-stromal cell interaction. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4162. doi:10.1158/1538-7445.AM2011-4162

Abstract 1762: Clinical relevance of plasma IL-6 and IL-6 levels in chronic lymphocytic leukemia (CLL)

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC It has been suggested that cytokines play an important role in the survival and proliferation of chronic lymphocytic leukemia (CLL) cells and these growth factors may be derived from a variety of cell types, including CLL cells. The plasma levels of the inflammatory cytokines, IL-6 and IL-8, vary in CLL and increased levels have been associated with a poor prognosis. This phenomenon has been related to the inhibition of apoptosis of CLL cells by the cytokines. In the present study, plasma IL-6 levels were measured by an ELISA assay in 193 CLL patients (107 males, 86 females; ages, 37-92 yr (median, 67.6 yr)) and the plasma IL-8 levels in 66 patients (31 males, 35 females; ages, 37-92 yr (median, 69 yr)). Samples were obtained from patients followed in the CLL Clinic at CancerCare Manitoba. Among the patients, plasma IL-6 levels ranged from 3 pg/mL, 8% in normals) and 25% had increased IL-8 (>10 pg/mL, 8% in normals). Plasma from CLL patients with high IL-6 levels was able to induce IL-6 expression in CLL cells whereas plasma from CLL patients with low IL-6 levels failed to induce IL-6 expression in CLL cells. This indicates that factor(s) within the microenvironment are contributing to increased IL-6 levels in CLL. We have previously shown that the relative survival decreases in CLL after age 65 yrs. The present study suggests that this may be related to a potentiation in the age-related increase in IL-6/IL-8 that is observed in the normal population. Whether the increase in mortality in elderly CLL patients is related to frailty/cardiovascular disease or to CLL progression is being investigated. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1762.