ALBERT

Description: Acute GVHD is a major cause of morbidity and mortality following NST. A high incidence of aGVHD occurs when CSA alone is used as prophylaxis. We investigated the effect of combining either mycophenolate mofetil (MMF) or an abbreviated course of low dose MTX with CSA on the incidence and severity of aGVHD. Between 11/97 and 07/07, 230 consecutive patients (pts) (solid tumors n=127, hematologic malignancies n=57, non-malignant hematologic disorders n=46) underwent conditioning with fludarabine (125mg/m2) and cyclophosphamide (120mg/kg), followed by a G-CSF mobilized PBSC transplant from an HLA identical (n=222: 96%) or 5/6 HLA-matched (n=8: 4%) related donor. Forty-eight pts with a history of heavy RBC transfusions or those receiving a 5/6 HLA-matched transplant had ATG (40mg/kg/d × 4 days) added to their conditioning. The initial cohort of pts (Group 1, n=66), received CSA alone (dose adjusted to maintain therapeutic serum levels) as GVHD prophylaxis. Due to the high incidence of severe aGVHD in this group, subsequent pts received CSA with either MMF (1 gram po bid; Group 2, n=82) or an abbreviated course of mini-dose MTX (5mg/m2 days +1, +3, +6; Group 3, n=82). In all three groups, decisions regarding discontinuation of CSA and MMF were based on donor T cell chimerism, presence of GVHD, and disease status. With a median follow-up of 2963, 2317 and 894 days in the three consecutive cohorts, a comparison was undertaken using competing risk analysis. The incidence of grades II–IV and III–IV GVHD was significantly higher in pts receiving CSA alone or CSA+MMF compared to those receiving CSA+MTX; the cumulative incidence of grades II–IV GVHD in the three groups was 56%, 59%, and 37% (p=0.05) while grades III–IV GVHD occurred in 30%, 34%, and 15% (p=0.019) respectively. The incidence of chronic GVHD (45% vs. 57% vs. 46%, p=0.27) was similar in the three groups. The lower incidence of aGVHD associated with MTX use was accompanied by a significantly improved TRM in group 3 pts; transplant related mortality was 21% in group 1, 21% in group 2 and 5% in group 3 pts (p=0.019). The impact of adding MMF or MTX to CSA on disease-specific outcome in pts with different malignant diseases could not be assessed due to small sample sizes. Conclusion: The addition of an abbreviated course of mini-dose methotrexate to CSA was associated with a significantly lower incidence of grades II–IV and III–IV aGVHD as well as lower TRM compared with CSA used alone or in combination with MMF in pts undergoing NST. To our knowledge this is the first report demonstrating a benefit of adding mini-dose MTX for GVHD prophylaxis in patients undergoing NST. Group 1 (N=66) Group 2 (N=82) Group 3 (N=82) P value Cumulative Incidence of Grade II–IV aGVHD (95% CI) 56% (44%–68%) 59%(48%–70%) 37%(25%–49%) 0.05 Cumulative Incidence of Grade III–IV aGVHD (95% CI) 30%(19%–41%) 34%(22%–46%) 15%(7%–23%) 0.019 Transplant Related Mortality(95% CI) 21%(11%–31%) 21%(12%–30%) 5%(0%–7%) 0.019 Proportion of Evaluable Pts with Chronic GVHD (%) 24/53 (45%) 43/75(57%) 34/74(46%) 0.274

Description: CD26 is a transmembrane glycoprotein with intrinsic dipeptidyl peptidase IV (DPPIV) activity as well as costimulatory activity of mitotic signals triggered by the CD3/TCR complex. Based on the expression level of CD26, CD4+ and CD8+ T cells can be divided into 3 (high/intermediate/low or negative) subsets. The significance of CD26 has been studied mainly on CD4+ T cells, and CD26highCD4+ T cells are considered to represent effector memory T cells of a typical Th1 phenotype producing IL2 and IFNg. Furthermore, we reported a significant decrease of this subset in CML patients under imatinib therapy in comparison to those under IFNa therapy and normal volunteers. In contrast, the role of each subset of CD8+ T cells has not yet been clarified. Multi-parameter flow cytometry analysis was performed to characterize CD8+ T cells differentially expressing CD26 in combination with intracellular detection of effector molecules such as perforin (P) and granzyme B (Gr). The capacity to secrete effector cytokines such as IFNg following short-term stimulation was also assessed. As a result, according to the expression level of CD26, we could clearly categorize CD8+ T cells as follows: CD26highCD8+ T cells are defined as central memory T cells which has a phenotype of CD45RO+CD28+CD27+ IFNg+Gr−P+/−, CD26intCD8+ T cells as naïve T cells of CD45ROCD28+ CD27+ IFNg−Gr−P−, and CD26lowCD8+ T cells as effector memory/effector T cells of CD45RO−/+ CD28−CD27−IFNg++Gr++P++, respectively. We next investigated the effects of imatinib on 3 distinct subsets during CD8+ T cell differentiation program. Peripheral blood mononuclear cells were primed with anti-CD3/CD28 MAb and subjected to the grading doses of imatinib for short term culture, followed by flow cytometory. CFSE labeling was used for monitoring cell proliferation. Intriguingly, we found that imatinib dose-dependently inhibits activation, cytokine production and proliferation of CD26highCD8+ central memory T cell subsets in a differentiation stage-specific manner. Finally, we compared the absolute number of peripheral blood CD26highCD8+ T cell subsets between 20 patients with CML in imatinib-induced CCR and 20 normal volunteers, clearly indicating a significant decrease of this subset in CML patients (22.30/ml vs 45.60/ml, p

Description: Purpose: Although rituximab is commonly used as induction and maintenance therapy for CD20+ malignant lymphoma, some patients become refractory to treatment and the mechanism of resistance is unclear. The aim of this study was to investigate the relationship between CD20 mutations and rituximab resistance. Methods: To investigate whether CD20 mutations affect the response to rituximab, fresh CD19+ lymphoma cells were isolated from the lymph nodes, peripheral blood or bone marrow of 48 patients with NHL using magnetic activated cell sorting (MACS). CD19+/CD20+ cells were subsequently sorted by flow cytometry. RNA was prepared from the isolated cells and RT-PCR was performed. The resulting PCR products were sequenced, subcloned into the mammalian expression vector pTARGET, transfected into K562 cells and CD20 expression was examined by flow cytometry and laser scanning confocal microscopy. Results: In all 48 patients, overall response rate (CR+CRu+PR) to rituximab was 93.8% (45/48), but two cases became PD after PR. DNA sequence analysis revealed that point mutations were mostly observed in two CD20 domains - the third transmembrane domain and the C-terminal cytoplasmic domain. One patient had point mutations in the transmembrane domain, three cases showed point mutations in the C-terminal cytoplasmic domain and six cases had non-specific CD20 mutations, which did not affect CD20 expression. Thirty-eight patients showed no mutations of CD20 gene. CD20 expression was very weak in patients with point mutations in the C-terminal cytoplasmic domain, whereas expression was increased in patients with point mutations in the transmembrane domain. Conclusions: This study suggests that point mutations in CD20 may cause rituximab resistance and identification of CD20 mutations upon diagnosis may help to predict a patient’s response to rituximab.

Description: Natural killer (NK) cell killer immunoglobulin-like receptor (KIR) interactions with self MHC class I molecules can regulate NK cell function; such interactions typically inactivate NK cells potentially providing a dominant mechanism through which malignant cells evade host NK cell-mediated immunity. Recently we found that the proteasome inhibitor bortezomib up-regulated surface expression of tumor necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAIL-R2) on a variety of different human malignant cells rendering them susceptible to NK cell-mediated apoptosis in vitro; this effect appears to override KIR ligand-mediated NK cell inactivation, overcoming tumor resistance to both allogeneic KIR ligand-matched and autologous NK cell cytotoxicity. We also found that murine tumors were sensitized by bortezomib to the cytotoxic effects of syngeneic NK cells; the killing of RENCA and LLC1 tumors in vitro by syngeneic BALB/c and C57BL/6 NK cells respectively was enhanced when tumors were exposed to 10nM of bortezomib for 18h. Here, we show that the combined treatment of bortezomib followed by syngeneic NK cell infusions significantly delays tumor growth in tumor bearing animals. While treatment with bortezomib or interleukin-2 activated syngeneic NK cells alone had little effect on tumor growth, the combined treatment significantly delayed growth of RENCA tumors in BALB/c mice and LLC1 in C57BL/6 mice (p

Description: Ligation of inhibitory receptors renders natural killer (NK) cells inactive against autologous tumors. Recently, the proteasome inhibitor bortezomib was shown to sensitize tumors to autologous NK-cell cytotoxicity in vitro. Here, we show bortezomib augments the antitumor effects of syngeneic NK-cell infusions in tumor-bearing animals; this effect is further enhanced in regulatory T cell (Treg cell)–depleted hosts. In vitro, bortezomib-treated tumors had higher tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) and perforin/granzyme-mediated caspase-8 activity, which enhanced their susceptibility to NK-cell lysis. Bioluminescence imaging of mice with established tumors showed treatment with bortezomib and syngeneic NK cells reduced tumor growth and prolonged survival compared with controls receiving bortezomib or NK cells alone. In contrast, tumor progression was not delayed when animals received bortezomib and perforin-deficient NK cells, showing drug-induced augmentation in NK-cell cytotoxicity was mediated through perforin/granzyme. Furthermore, tumor growth was slower in bortezomib-treated recipients when host Treg cells were eradicated with anti-CD25 antibody before infusing NK cells compared with mice without Treg-cell ablation (tumor doubling time, 16.7 vs 4.9 days, respectively; P = .02). These findings suggest that depletion of Treg cells followed by bortezomib-induced tumor sensitization to autologous NK cells could be used as a novel strategy to treat cancer.

Description: The activation of NK cell inhibitory receptors may limit the antitumor efficacy of adoptive autologous and allogeneic NK cell infusions. Recently, we found that exposing malignant cells to the proteosome inhibitor bortezomib upregulated surface expression of death receptors for TRAIL, resulting in significant enhancement of autologous NK cell tumor cytotoxicity in vitro and in vivo. Here we show that NK cells expanded in vitro in the presence of IL-2 and EBV-LCL feeder cells upregulate surface expression of TRAIL which significantly augments bortezomib-induced tumor sensitization to NK cell killing. CD56+/CD3– NK cells were isolated from normal donors by immuno-magnetic bead selection and were co-cultured with irradiated EBV-LCL feeder cells in X-VIVO 20, 10% human AB serum, and 500 IU/ml hrIL-2 for up to 21 days. Depending on culture conditions, a 300 to 10,000 fold increase in NK cell numbers was achieved. Non-expanded and expanded NK cells were analyzed by flow cytometry for the expression of CD56, CD16, TRAIL, FasL, NKG2D, LFA-1, perforin, and granzymes A and B at baseline and ≥ 10 days following in vitro expansion. Chromium release assays were performed to assess fresh vs. expanded NK cell cytotoxicity of renal cell carcinoma (RCC) tumor targets treated with 10 nM bortezomib for 18 hr vs. untreated RCC controls. Freshly-isolated NK cells did not express TRAIL or FasL; in contrast NKG2D, LFA-1, perforin and granzymes A and B were constitutively expressed in fresh NK cells. After expansion, there was a dramatic increase in surface expression of TRAIL and NKG2D; on fresh vs. expanded NK cells from 3 different donors, TRAIL expression increased from 0% to 80.8±15.4% (mean fluorescence intensity [MFI] of TRAIL increased from 6.0±5.1 to 37.9±3.2). The MFI of NKG2D surface expression also increased following NK cell expansion (432.0±70.9 from 48.3±16.3). Expression of LFA-1 and perforin did not change, although there was a small increase in surface and intracellular expression of FasL and granzymes A and B respectively. At a 1:1 effector to target ratio, fresh NK cells lysed 3.4± 2.1% and 5.0± 2.7% of untreated and bortezomib-treated RCC tumor cells respectively. In contrast, there was a dramatic increase in bortezomib-treated tumor susceptibility to killing by expanded NK cells; NK cells expanded for 12-18 days killed 27.6± 9.3% and 55.8± 8.3% of untreated vs. bortezomib-treated RCC tumor cells respectively. Conclusion: In vitro-expanded NK cells are phenotypically and functionally different from non-expanded NK cells. Expanded cells have increased NKG2D and TRAIL expression and greatly enhanced TRAIL-mediated tumor cytotoxicity compared to non-expanded NK cells. Based on these findings, a phase I trial investigating the safety and anti-tumor effects of escalating doses of adoptively-infused ex vivo-expanded autologous NK cells following bortezomib treatment in patients with advanced metastatic tumors and hematological malignancies has recently been initiated. Figure: Freshly isolated and expanded Nk cell lysis of renal cell carcinoma cell line with and without treatment of tumor cells with bortezomib Figure:. Freshly isolated and expanded Nk cell lysis of renal cell carcinoma cell line with and without treatment of tumor cells with bortezomib

Description: The proteasome inhibitor bortezomib was recently found to render tumor cells susceptible to natural killer (NK) cell-mediated apoptosis in vitro and in vivo. This sensitization appears to occur as a consequence of this agent up-regulating surface expression of tumor necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAIL-R2) on human malignant cells rendering them susceptible to TRAIL-mediated NK cell cytotoxicity. We hypothesized that bortezomib would likewise sensitize tumors to the cytotoxic effects of antigen specific T-cells through similar apoptotic pathways, thereby providing an incentive to use bortezomib as a universal immune-sensitizing agent. The HLA-A2+, gp100+, MART-1+ melanoma cell lines 526 and 624 were treated with 10nM bortezomib for 18 hrs then were analyzed by FACS for expression the cell surface markers (HLA-ABC, MIC-A/B, TRAIL-R1/2 and Fas) and Cr51 cytotoxicity assay for susceptibility to CD8+/HLA-A2+ restricted gp100 and MART-1 specific CTL-mediated lysis. As observed previously, NK cell-mediated apoptosis was significantly higher in tumor cells treated with bortezomib compared to untreated tumor cells. In contrast, an unanticipated and significant reduction in CTL-mediated cytotoxicity was observed in tumors treated with bortezomib compared to untreated tumors; at an effector:target ratio of 3:1, NK cell cytotoxicity increased from 43±2% to 70±2% (p

Description: Background: Within the concept of reduced-intensity stem cell transplantation (RIST), there is a wide range of differences in regimens utilized, in terms of toxicities and antileukemia effects, and only a little information is available on the clinical impact of chimerism status in patients conditioned with a busulfan-containing regimen. To examine this point, we reviewed the pattern of lineage-specific chimerism to correlate with subsequent clinical outcomes. Patients and Methods: We retrospectively reviewed the data of 117 patients (median age, 52 years: range, 29–68) who had various hematological malignancies and underwent busulfan-containing RIST with related blood stem cells (n=81), related marrow (n=4) or unrelated marrow (n=32), between January 2000 and December 2006. The conditioning regimen consisted of busulfan (8 mg/kg) and fludarabine (180 mg/m2, n=64) or cladribine (0.66 mg/kg, n=53), with or without 2–4 Gy TBI (n=26) or anti-thymocyte globulin (5–10 mg/kg: n=31). Prophylaxis for GVHD consisted of cyclosporin or tacrolimus, with or without methotrexate. Chimerism was evaluated with peripheral blood samples taken on days 30, 60 and 90 after transplantation by PCR-based amplification of polymorphic short tandem repeat regions. Results: The median follow-up of surviving patients was 857 days (50–2535). Percent donor-chimerism was significantly higher in granulocytes than T-cell fraction throughout the entire course, and the mean values were, respectively, 96% vs 83%, 98% vs 89% and 98% vs 91% at days 30, 60 and 90 after RIST. At day 30, the numbers of patients with T-cell chimerism 〉90%, 60–90% and

Description: This study found that MS-275, a novel synthetic benzamide histone deacetylase inhibitor (HDACI), blocked Akt/mTOR signaling in acute myelogenous leukemia (AML) HL60 and acute promyelocytic leukemia (APL) NB4 cells, as assessed by decreased levels of the phosphorylated (p)-Akt, p-p70 ribosomal S6 kinase (p70S6K), and p-S6K by Western blot analysis. Interestingly, further inactivation of mTOR by rapamycin analogue RAD001 (everolimus) significantly enhanced MS-275-mediated growth inhibition and apoptosis of these cells in parallel with enhanced upregulation of p27 kip1 and downregulation of c-Myc. In addition, RAD001 potentiated the ability of MS-275 to induce differentiation of HL60 and NB4 cells, as measured by expression of CD11b cell surface antigens, as well as reduction of nitroblue tetrazolium. Importantly, RAD001 potentiated the ability of MS-275 to induce expression of the myeloid differentiation-related transcription factor CCAAT enhancer binding protein e in these cells in association with enhanced acetylation of histone H3 on its promoter. Furthermore, RAD001 (5 mg/kg) significantly enhanced the effects of MS-275 (10 mg/kg) to inhibit proliferation of HL60 tumor xenografts in nude mice without adverse effects. Taken together, concomitant administration of a HDACI and a mTOR inhibitor may be a promising treatment strategy for the individuals with a subset of human leukemia.

Description: Abstract 4763 INTRODUCTION Peripheral blood involvement (leukemic presentation) is considered as a part of bone marrow involvement and detected about 18% of bone marrow (BM) involvement of follicular lymphoma (FL). It is not known whether leukemic presentation is an adverse prognostic factor in rituximab era. METHOD We retrospectively evaluate prognostic value of peripheral blood involvement in patients with follicular lymphoma received rituximab containing regimen as an initial therapy from October 2000 to January 2009. Leukemic presentation was defined by morphologic identification of an abnormal lymphoid population in the peripheral blood. RESULT Total 129 patients were treated with rituximab containing initial therapy. Bone marrow involvement was detected in 39 /108 (36.1%) patients and leukemic presentation was identified in 8 / 39 (20.5%) of patients with BM involvement. Leukemic presentation shows significant poorer progression free survival than BM involvement without peripheral blood involvement. (2yr PFS 23.4% vs 73.3% p=0.015) Multivariate analysis conducted by Cox proportional hazard analysis including five variables of FLIPI revealed Hb