Two death pathways induced by sorafenib in myeloma cells: puma-mediated apoptosis and necroptosis

Purpose. Sorafenib is a multikinase inhibitor that targets the MAPK pathway and is currently used for the treatment of hepatocellular and renal carcinoma. Recently, it has been shown that sorafenib is also cytotoxic to multiple myeloma (MM) cells. Here, we have further analyzed the mechanism of sorafenib-induced death in MM cells. Methods. Cell death induced by sorafenib in MM cell lines and in plasma cells from MM patients was evaluated by analysis of gene expression by RT-MLPA and quantitative PCR, protein levels and functionality by Western blot and flow cytometry and gene silencing with siRNA. Results. Cell death was characterized by phosphatidylserine exposure, ΔΨm loss, cytochrome c release and caspase activation, hallmarks of apoptosis. DL50 at 24 h ranged from 6 to 10 µM. Ex vivo treatment with 20 µM sorafenib induced apoptosis in around 80 % myeloma cells from six multiple myeloma patients. Sorafenib induced caspase-dependent degradation of Bcl-xL and Mcl-1 proteins, destabilizing the mitochondria and speeding up the development of apoptosis. Sorafenib treatment increased levels of Puma at mRNA and protein level and gene silencing with siRNA confirmed a relevant role for Puma in the induction of apoptosis. Co-treatment with the pan-caspase inhibitor Z-VAD-fmk prevented cell death to a variable degree depending on the cell line. In RPMI 8226 cells, Z-VAD-fmk prevented most of sorafenib-induced death. However, death in MM.1S was only prevented by co-incubation with both Z-VAD-fmk and the RIP1K inhibitor necrostatin-1, indicating that under conditions of inefficient caspase activation, sorafenib induces death by necroptosis. Conclusion. Our results demonstrate a key role for Puma in the triggering of sorafenib-induced apoptosis and that this drug can also induce death by necroptosis in multiple myeloma cells (AU)

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Two death pathways induced by sorafenib in myeloma cells: Puma-mediated apoptosis and necroptosis.

PURPOSE: Sorafenib is a multikinase inhibitor that targets the MAPK pathway and is currently used for the treatment of hepatocellular and renal carcinoma. Recently, it has been shown that sorafenib is also cytotoxic to multiple myeloma (MM) cells. Here, we have further analyzed the mechanism of sorafenib-induced death in MM cells. METHODS: Cell death induced by sorafenib in MM cell lines and in plasma cells from MM patients was evaluated by analysis of gene expression by RT-MLPA and quantitative PCR, protein levels and functionality by Western blot and flow cytometry and gene silencing with siRNA. RESULTS: Cell death was characterized by phosphatidylserine exposure, ΔΨm loss, cytochrome c release and caspase activation, hallmarks of apoptosis. DL50 at 24 h ranged from 6 to 10 µM. Ex vivo treatment with 20 µM sorafenib induced apoptosis in around 80 % myeloma cells from six multiple myeloma patients. Sorafenib induced caspase-dependent degradation of Bcl-xL and Mcl-1 proteins, destabilizing the mitochondria and speeding up the development of apoptosis. Sorafenib treatment increased levels of Puma at mRNA and protein level and gene silencing with siRNA confirmed a relevant role for Puma in the induction of apoptosis. Co-treatment with the pan-caspase inhibitor Z-VAD-fmk prevented cell death to a variable degree depending on the cell line. In RPMI 8226 cells, Z-VAD-fmk prevented most of sorafenib-induced death. However, death in MM.1S was only prevented by co-incubation with both Z-VAD-fmk and the RIP1K inhibitor necrostatin-1, indicating that under conditions of inefficient caspase activation, sorafenib induces death by necroptosis. CONCLUSION: Our results demonstrate a key role for Puma in the triggering of sorafenib-induced apoptosis and that this drug can also induce death by necroptosis in multiple myeloma cells.

Farnesyltransferase inhibitor BMS-214662 induces apoptosis in B-cell chronic lymphocytic leukemia cells.

B-cell chronic lymphocytic leukemia (B-CLL) cells develop resistance to nucleoside analogs over time. This chemoresistance may be caused by selection for B-CLL cells with defects in the particular apoptosis pathway triggered by these drugs. Therefore, anticancer agents that induce apoptosis through alternative pathways might be useful in treating chemoresistant B-CLL. Farnesyltransferase inhibitors (FTIs) are a class of synthetic drugs with definite molecular targets, which have demonstrated cytotoxicity against leukemic cell lines. We have studied the ex vivo effect of the FTI BMS-214662 on cells from 18 patients with B-CLL. Low concentrations (<1 microM) of BMS-214662 prevented farnesylation of the chaperone marker HDJ-2 and had no effect on Akt activation. BMS-214662 induced apoptosis in B-CLL cells from all patients studied, including those showing resistance to cladribine and fludarabine ex vivo and in vivo. Treatment with BMS-214662 induced loss of mitochondrial membrane potential (DeltaPsi(m)), phosphatidylserine exposure, proapoptotic conformational changes of Bax and Bak, reduction in Mcl-1 levels and activation of caspases 9 and 3. The general caspase inhibitor Z-VAD-fmk did not prevent BMS-214662-induced cell death. These results indicate that BMS-214662 may be a useful drug for treating B-CLL and, in particular, an alternative for the therapy of purine analog-resistant or relapsed B-CLL.

[Unstable angina in octogenarians: is an invasive approach feasible and effective?]. / Angina inestable en el paciente octogenario: ¿es factible y eficaz el abordaje invasivo?

BACKGROUND AND OBJECTIVE: Octogenarian patients with unstable angina are usually managed more conservatively despite having a worse prognosis. Studies of balloon angioplasty in the elderly have demonstrated a higher incidence of adverse events but the new advances (mainly stenting) have improved the results. We evaluated the efficacy and safety of an invasive approach in octogenarians with unstable angina. PATIENTS AND METHOD: From January 1996 to October 1999, 100 patients at least 80 years old with unstable angina were admitted to our unit and among these, 74 (74%) underwent percutaneous revascularization. We evaluated immediate results, in-hospital events and clinical follow-up. RESULTS: A total of 145 lesions were treated in 74 patients. The stent implantation rate was 79%. The success rate was 92%. Two patients died during hospitalization due to cardiac causes and 1 patient had a non-Q infarction. At follow-up, 24 +/- 12 months (range: 4 -50 months) 14 patients died (19.4%). New revascularization was performed in 10 patients (13.5%), 9 with PTCA and 1 with surgery. The survival rate free of death and infarction in the first year was 89.2%. At the end of follow-up 58 patients were alive (78.4%), 45 asymptomatic and 13 had stable angina, class I or II. CONCLUSIONS: The results of stent implantation in octogenarians were good with a 92% procedural success. Ninety-six percent of patients were free of death and infarction during hospitalization and 78.4% of the patients remained alive, most of them asymptomatic at the end of follow-up.

[Intravascular ultrasonographic evaluation of direct stents, implanted without predilatation. Comparison of results according to lesion types]. / Evaluación con ultrasonografía intravascular de stents implantados sin predilatación (stents directos). Comparación de resultados según el tipo de lesión.

INTRODUCTION AND OBJECTIVES: Direct stenting is a safe and feasible technique in selected lesions yielding excellent angiographic results. However, there are no studies providing intravascular ultrasonographic examination after direct stenting. The aim of this study was to evaluate direct stent expansion with ultrasonography and to know whether there are differences in the results based on lesion types. METHODS: Patients with amenable lesions for direct stenting were enrolled; including patients with no occlusion, no calcification, no significant tortuosity or angulation, a length 15 mm and a reference lumen diameter 2.5 mm. Intravascular ultrasonography was performed after stent implantation. The ultrasonographic criteria for optimal expansion were: complete apposition and a minimal intrastent lumen area > 80% of the average reference luminal area and 90% of the distal reference lumen area. RESULTS: We included 40 patients (50 lesions). The final angiographic result was good in all the patients but in one case an additional stent was used due to dissection. The ultrasonographic examination did not show significant differences between type A and B lesions. Optimal expansion was achieved in 14/21 (66%) of type A lesions and 17/29 (58%) of type B lesions (p = 0.5). The balloon/artery ratio was the only factor significantly related to ultrasonographic results. When this ratio was 1.1-1.2 (25 cases), 76% of the stents were optimally expanded and when the ratio was < 1. 1 (25 cases) only in a 48% an optimal result was achieved (p < 0.05). CONCLUSIONS: Direct stenting in selected lesions provides ultrasonographic results comparable to those expected with conventional stenting and these results could be even improved if a balloon artery ratio 1.1-1.2 is used. Taking into consideration the selection criteria the differences observed between lesion types A and B are not significant.