Background: Patients with synchronous metastastic breast cancer and intact primary tumor traditionally undergo systemic treatment. Surgical intervention at the primary site is typically reserved for palliation and often replaceable by radiation. Nevertheless, local surgery in metastatic breast cancer has become an issue of great controversy since retrospective studies published during the recent years suggested a slight benefit from an operative procedure. We evaluated the effect of surgery on long-term survival and progression-free survival in synchronous stage IV breast cancer. Methods: We retrospectively reviewed the records of all breast cancer patients treated at our institution between 1986 and 2007. Information recorded for each patient included age, tumor characteristics, metastasis characteristics, therapy, progression-free survival, and overall survival. Survival data were compared between surgical and nonsurgical patients. Results: 61 patients with synchronous metastastic breast cancer and intact primary tumor were analyzed. 26 patients (43%) received no primary site surgery and 35 (57%) patients had surgery. Overall survival and progression-free survival determined via the Kaplan-Meier method showed no significant difference between the surgery and the non-surgery group. Conclusion: In patients with metastatic breast cancer, the operation of the primary tumor did not influence overall survival or progression-free survival.

Honokiol, an active component isolated and purified from Chinese traditional herb magnolia, was demonstrated to inhibit growth and induce apoptosis of different cancer cell lines such as human leukaemia, colon, and lung cancer cell lines; to attenuate the angiogenic activities of human endothelial cells in vitro; and to efficiently suppress the growth of angiosarcoma in nude mice. In this study, we have demonstrated that treatment of different human breast cancer cell lines with honokiol resulted in a time- and concentration-dependent growth inhibition in both estrogen receptor-positive and -negative breast cancer cell lines, as well as in drug-resistant breast cancer cell lines such as adriamycin-resistant and tamoxifen-resistant cell lines. The inhibition of growth was associated with a G1-phase cell cycle arrest and induction of caspase-dependent apoptosis. The effects of honokiol might be reversely related to the expression level of human epidermal growth receptor 2, (HER-2, also known as erbB2, c-erbB2) since knockdown of her-2 expression by siRNA significantly enhanced the sensitivity of the her-2 over-expressed BT-474 cells to the honokiol-induced apoptosis. Furthermore, inhibition of HER-2 signalling by specific human epidermal growth receptor 1/HER-2 (EGFR/HER-2) kinase inhibitor lapatinib synergistically enhanced the anti-cancer effects of honokiol in her-2 over-expressed breast cancer cells. Finally, we showed that honokiol was able to attenuate the PI3K/Akt/mTOR (Phosphoinositide 3-kinases/Akt/mammalian target of rapamycin) signalling by down-regulation of Akt phosphorylation and upregulation of PTEN (Phosphatase and Tensin homolog deleted on chromosome Ten) expression. Combination of honokiol with the mTOR inhibitor rapamycin presented synergistic effects on induction of apoptosis of breast cancer cells. In conclusion, honokiol, either alone or in combination with other therapeutics, could serve as a new, promising approach for breast cancer treatment.

Objectives: Mantle cell lymphoma (MCL) is an incurable B cell lymphoma, and novel treatment strategies are urgently needed. We evaluated the effects of combined treatment with the proteasome inhibitor bortezomib and the histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA) on MCL. Bortezomib acts by targeting the proteasome, and - among other mechanisms - results in a reduced nuclear factor-kappa B (NF-kappa B) activity. HDACi promote histone acetylation, and also interfere with NF-kappa B signaling. Methods: Human MCL cell lines (JeKo-1, Granta-519 and Hbl-2) were exposed to bortezomib and/or SAHA. Cell viability and apoptosis were quantified by the MTT and annexin-V assay, respectively. Reactive oxygen species (ROS) were analyzed using the fluorophore H(2)DCFDA. In addition, activated caspases, proteasome- and NF-kappa B activity were quantified. Results: Combined incubation with bortezomib and SAHA resulted in synergistic cytotoxic effects, as indicated by combination index values < 1 using the median effect method of Chou and Talalay. The combination of both inhibitors led to a strong increase in apoptosis as compared to single agents and was accompanied by enhanced ROS generation, while each agent alone only modestly induced ROS. The free radical scavenger N-acetyl-1-cysteine blocked the ROS generation and reduced the apoptosis significantly. In addition, coexposure of bortezomib and SAHA led to increased caspase-3, -8 and -9 activity, marked reduction of proteasome activity and decrease of NF-kappa B activity. Conclusions: This is the first report giving evidence that SAHA and bortezomib synergistically induce apoptosis in MCL cells. These data build the framework for clinical trials using combined proteasome and histone deacetylase inhibition in the treatment of MCL.

Proteasome inhibitors represent novel anti-cancer drugs which interact with the proteasome–ubiquitin pathway. The 26S proteasome is a multicatalytic threonine protease with three distinct catalytic activities. It is responsible for intracellular protein turnover in eukaryotic cells, including the processing and degradation of short- and some long-living proteins required for regulation of various cellular functions. Subsequently, the inhibition of the proteasomal function results in stabilization and accumulation of its substrates, which notably include cyclins, cyclin-dependent kinase inhibitors, transcriptional factors, tumor suppressor proteins and proto-oncogenes. This results in confounding signals in the cell inducing cell cycle arrest and activation of apoptotic programs. Acting on transcriptional factor NF-κB, which is upregulated in some tumors undergoing chemotherapy or irradiation and downregulated by proteasome inhibition, a significant chemosensitization and consequently synergistic effects concerning the anti-tumor activity could be achieved. Bortezomib is the first proteasome inhibitor that has entered clinical trials. In multiple myeloma, both the US Food and Drug Administration and European Medicine Evaluation Agency granted approval for the use of bortezomib (Velcade) for the treatment of multiple myeloma patients who have received at least two prior therapies and have demonstrated disease progression on the last therapy. At present, other trials examine the activity in a variety of solid tumors and hematological malignancies. This paper reviews preclinical and clinical results.

Proteasome inhibitor bortezomib interacts with the regulation of protein turnover in eukaryotic cells. The results of proteasomal inhibition consist in cell cycle arrest and induction of apoptosis. Etoposid targets topoisomerase IIα and is included in several protocols for myeloma treatment. In this study, we examined the effects of simultaneous and sequential treatments of bortezomib and the topoisomerase IIα inhibitor etoposide in multiple myeloma cell lines, particularly in terms of potential synergistic effects between both drugs. Using the MTT assay, cytotoxicity levels for dosages ranging from 0.01 nM and 100 nM for bortezomib and 0.001 μM and 100 μM for etoposide in multiple myeloma cell lines OPM-2, NCI-H929 and RPMI-S were determined and IC50 values calculated. In each experiment, cells were treated with each drug individually and with fixed ratios of both drugs simultaneously (co-incubation over 48 h) and sequentially (pre-incubation with etoposide for 24 h and co-incubation with bortezomib for additional 24 h). The data were analyzed using the median effect method of Chou and Talalay, whereas the combination indices (CI) were calculated for each level of cytotoxicity. A CI< 1 indicated synergy, a CI= 1 indicated additivity and a CI> 1 indicated antagonism. In the sequential treatment schedule, we found synergistic effects in all three cell lines, even at low single-agent cytotoxicity levels (fractional inhibition <50%). Synergistic action were found in RPMI-S with a CI-range between 0.08 and 0.9, in OPM-2 between 0.05 and 0.07 and in NCI-H929 between 0.65 and 0.86 in different doses of both drugs. Interestingly, when cells were treated simultaneously with both drugs, no synergistic effects were observed. On cellular level, we found cell cycle arrest in the G2-M phase of the cell cycle, when cells were treated with both drugs sequentially. Furthermore, we noticed a correlation between the etoposide-sensitivity and G2-M/S-fraction of the sample, indicating that prolonged drug action in the G2-M/S-phase might contribute to enhanced growth inhibitory effects. On sub-cellular level, the synergy was accompanied by diminished activation of transcriptional factor NF-κB, whereas bortezomib abrogated the etoposide-induced NF-κB up-regulation. This effect was accompanied by down-regulation of Bcl-2, an anti-apoptotic protein and transcriptional product of NF-κB. Furthermore, when cells were treated simultaneously with both drugs, we noticed a translocation of topoisomerase IIα from nucleus into the cytoplasm, where the enzyme remained inactive. In sequential treatment schedule, no translocation of topoisomerase IIα was observed, indicating that the drug target remained in its functional compartment. In conclusion, our data show strong synergistic effects between bortezomib and etoposide in appropriate treatment schedules at low drug concentrations in vitro, indicating that the drug combination might be useful for clinical trials in multiple myeloma patients.