16534 Background: Pegylated filgrastim is a new formulation of a granulocyte colony-stimulating factor that has a long circulating half-life, permitting a single dose of filgrastim per cycle of chemotherapy. Methods: To evaluate whether a single subcutaneous injection of pegfilgrastim (6 mg) is as safe and effective as daily filgrastim (5 mcg/kg/day), 40 consecutive autologous stem cell transplantations performed for breast cancer and lymphomas have been analysed. Median age was 47 yrs (20–61) and 48 yrs (30–63) in pegfilgrastim and filgrastim group, respectively. All patients had normal bone marrow biopsy. The first cohort of patients received 5 mcg/kg/day of filgrastim starting from day 5 post transplantation and the second cohort of patients received a single subcutaneous injection of 6 mg pegfilgrastim on day 5 after transplantation. Results: Median duration of grade 4 neutropenia in the pegfilgrastim and filgrastim groups was 7 (4–9) and 6 (5–9) days, respectively (P 0.29). Neutropenic fever incidence was significantly higher in filgrastim group, 9/20 vs 16/20 (P 0.048), the median duration was not significantly different, 1 (1–6) vs 3 (1–7) days. The grade 3–4 mucositis was higher in filgrastim patient group, 4/20 vs 13/20 in pegfilgrastim and filgrastim, respectively (P 0.009). The adverse events observed during post-transplant aplasia were attributable to complications arising from myelo-suppressive chemotherapy or the primary disease. The only occurring adverse event considered to be cytokine related was mild to moderate bone pain. The overall incidence of bone pain requiring non-narcotic analgesia was not statistically different, 20% (4/20) in pegfilgrastim patients and 40% (8/20) in filgrastim patients. The patients in filgrastim group received a mean of 9.8 daily injections. Conclusions: A single injection of pegfilgrastim administered at day 5 post transplant shows comparable safety and efficacy profiles to daily injections of filgrastim and may be cost-effective. No significant financial relationships to disclose.

PURPOSE:Bcl-2 overexpression is frequently detected in lymphoid malignancies, being associated with poor prognosis and reduced response to therapy. Here, we evaluated whether Bcl-2 overexpression affects the cytotoxic activity of proteasome inhibitors taken alone or in association with conventional anticancer drugs or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). EXPERIMENTAL DESIGN:Jurkat cells engineered to overexpress Bcl-2 were treated with proteasome inhibitors (MG132, epoxomicin, and bortezomib), anticancer drugs (etoposide and doxorubicin), TRAIL, or combinations of these compounds. Cell death and loss of mitochondrial transmembrane potential were detected by flow cytometry. Cytosolic relocalization of cytochrome c and SMAC/Diablo, caspase cleavage, and Bcl-2 and Mcl-1 levels were determined by immunoblotting. Nuclear factor-kappaB inhibition was done by retroviral transduction with a dominant-negative mutant of IkappaBalpha. RESULTS:Bcl-2 overexpression results in significant inhibition of apoptosis in response to proteasome inhibitors, antiblastics, and TRAIL. Addition of TRAIL to proteasome inhibitors results in a synergistic cytotoxic effect in Bcl-2-overexpressing cells, whereas this result is not reproduced by the combination of proteasome inhibitors with antiblastic drugs. Importantly, proteasome inhibitors plus TRAIL induce mitochondrial dysfunction irrespective of up-regulated Bcl-2. Bcl-2 cleavage to a fragment with putative proapoptotic activity and elimination of antiapoptotic Mcl-1 may both play a role in proteasome inhibitors-TRAIL cooperation. Conversely, nuclear factor-kappaB inhibition by proteasome inhibitors is per se insufficient to explain the observed synergy. CONCLUSIONS:Combined proteasome inhibitors and TRAIL overcome the apoptotic threshold raised by Bcl-2 and may prove useful in the treatment of chemoresistant malignancies with up-regulated Bcl-2.

In cancer patients, the ability to detect disseminated tumour cells in peripheral blood or bone marrow could improve prognosis and consent both early detection of metastatic disease and monitoring of the efficacy of systemic therapy. These objectives remain elusive mainly due to the lack of specific genetic markers for solid tumours. The use of surrogate tissue-specific markers can reduce the specificity of the assays and give rise to a clinically unacceptable false-positive rate. Mammaglobin (MAM) and maspin are two putative breast tissue-specific markers frequently used for detection of occult tumour cells in the peripheral blood, bone marrow and lymph nodes of breast cancer patients. In this study, it was evaluated whether MAM and maspin gene expression may be induced in the normal blood and bone marrow cells exposed to a panel of cytokines, including chemotactic factors (C5a, interleukin (IL)-8), LPS, proinflammatory cytokines (TNF- α , IL-1 β ) and growth factors (IL-3, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor). The experimental data show that all cytokines included in the panel, except for IL-8, were able to induce maspin expression; on the contrary, MAM gene was never induced. These results suggest that MAM is more specific than maspin and that the possible interference of cytokines should be taken into account in interpreting molecular assays for detection of isolated tumour cells.

Purpose: Overexpression of antiapoptotic Bcl-2 family members has recently been related to resistance to chemo/radiotherapy in several human malignancies, particularly lymphomas. Hence, innovative approaches bypassing this resistance mechanism are required in the therapeutic approach. This study evaluated whether chemoresistance associated with Bcl-2 and Bcl-xL overexpression would be overcome by activating the death receptor pathway by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in the Jurkat cell model Experimental Design: We made use of genetically modified Jurkat cells to evaluate the effect of Bcl-2 or Bcl-xL overexpression on the cytotoxic effect produced by the anticancer drugs doxorubicin, etoposide, and oxaliplatin and TRAIL. Caspase activation was detected by cleavage of caspase-8 and -3. The mitochondrial transmambrane potential was assessed by staining with DiOC6 and flow cytometry. Caspase activity was blocked by the broad-spectrum caspase inhibitor zVAD-fmk. Results: Bcl-2 and Bcl-xL overexpression but not lack of caspase-8 protects the Jurkat cells from the anticancer drug-induced cytolysis. However, Bcl-2/Bcl-xL Jurkat cells retained some susceptibility to TRAIL-induced cytolysis. A highly synergistic cytotoxic effect of the combination of TRAIL with any of the antiblastic used in this study was detected in the chemoresistant cells. This effect was associated with mitochondrial disassemblage and dependent on caspase activation Conclusions: The combination of TRAIL with conventional anticancer drugs may prove to be useful in the treatment of antiapoptotic Bcl-2 family proteins-expressing malignancies.