Mcl-1 is a Bcl-2 family protein which can act as an apical molecule in apoptosis control, promoting cell survival by interfering at an early stage in a cascade of events leading to release of cytochrome c from mitochondria. Mcl-1 has a short half life and is a highly regulated protein, induced by a wide range of survival signals and also rapidly down regulated during apoptosis. Mcl-1 can also readily be cleaved by caspases during apoptosis to produce a cell death promoting molecule. The multiple levels of control of Mcl-1 expression suggest that Mcl-1 plays a critical role in controlling life and death decisions in response to rapidly changing environmental cues and Mcl-1 is required for embryonic development and the function of the immune system. Expression of Mcl-1 may be useful in informing decision making in the treatment of various cancers, and countering Mcl-1 function may be an attractive therapeutic strategy in malignancy, inflammatory conditions and infectious disease where Mcl-1 may play a major role in suppressing apoptosis.

Enforced expression of the antiapoptotic Bcl-2 family protein Mcl-1 promotes lymphomagenesis in the mouse; however, the functional role of Mcl-1 in human B-cell lymphoma remains unclear. We demonstrate that Mcl-1 is widely expressed in malignant B-cells, and high-level expression of Mcl-1 is required for B-lymphoma cell survival, since transfection of Mcl-1-specific antisense oligodeoxynucleotides was sufficient to promote apoptosis in Akata6 lymphoma cells. Mcl-1 was efficiently cleaved by caspases at evolutionarily conserved aspartic acid residues in vitro, and during cisplatin-induced apoptosis in B-lymphoma cell lines and spontaneous apoptosis of primary malignant B-cells. Overexpression of the Mcl-1 cleavage product that accumulated during apoptosis was sufficient to kill cells. Therefore, Mcl-1 is an essential survival molecule for B-lymphoma cells and is cleaved by caspases to a death-promoting molecule during apoptosis. In contrast to Mcl-1, Bcl-2 and Bcl-X L were relatively resistant to caspase cleavage in vitro and in intact cells. Interfering with Mcl-1 function appears to be an effective means of inducing apoptosis in Mcl-1-positive B-cell lymphoma, and the unique sensitivity of Mcl-1 to caspasemediated cleavage suggests an attractive strategy for converting it to a proapoptotic molecule.

No abstract

Bcl-X L is a Bcl-2-related survival protein that is essential for normal development. Bcl-X L expression is rapidly induced by a wide range of survival signals and many cancer cells constitutively express high levels. The Bcl-X gene has a complex organization with multiple promoters giving rise to RNAs with alternate 5 0 non-coding exons. Here we have investigated the mechanisms that control basal and induced expression of Bcl-X L in B-lymphoma cells. Antisense experiments demonstrated that Bcl-X L was essential for survival of Akata6 B-lymphoma cells. The levels of RNAs containing the IB Bcl-X non-coding exon, derived from the distal 1B promoter, correlated with basal expression of Bcl-X L in primary malignant B cells and this promoter was highly active in B-cell lines. The activity of this promoter was largely dependent on a single Ets binding site and Ets family proteins were bound at this promoter in intact cells. CD40 ligand (CD40L)-induced cell survival was associated with increased Bcl-X L expression and accumulation of exon IA-containing RNAs, derived from the proximal 1A promoter. Nuclear factor-kappaB (NF-jB) inhibition prevented induction of Bcl-X L protein and exon IA-containing RNAs by CD40L. Therefore, the distal Bcl-X 1B promoter plays a critical role in driving constitutive expression-mediated via Ets family proteins in malignant B cells, whereas NF-jB plays a central role in the induction of Bcl-X L in response to CD40 signalling via the proximal 1A promoter.

Background: This study investigated the safety, pharmacokinetics (PK) and clinical antitumor activity of ABT-751, a novel sulfonamide antimitotic and vascular disrupting agent, in combination with docetaxel (Taxotere) in patients with castration-resistant prostate cancer (CRPC). expanded. Overall, severe adverse events occurred more commonly on DL 4 than 3 (47% versus 18% of patients). PK data for docetaxel and ABT-751 were similar to reported literature. Best post-treatment prostate-specific antigen decline of ‡50% occurred in 60% and objective responses occurred in 45% of patients. Median overall survival was 24 months (95% confidence interval 8.3-37.7 months). Conclusions:The combination of ABT-751 and docetaxel is safe and active in CRPC. Based on the cumulative safety analysis, the recommended phase II dose of ABT-751 is 200 mg daily with docetaxel 60 mg/m 2 for this patient population.

Signet-ring cell cancers deriving from the bladder are rare entities and usually present with advanced incurable disease and associated poor outlook. No standard effective chemotherapeutic option has been described largely due to the rarity of this malignancy. We report a case of a patient with metastatic bladder cancer, signet-ring cell variant. The patient progressed rapidly on standard first-line bladder cancer chemotherapy with gemcitabine and carboplatin. He responded well to second-line capecitabine with a clinically meaningful progression-free survival.

No abstract

SummaryIn the present study, we investigated the expression of Mcl-1 and Bcl-2 by immunohistochemistry in 85 patients of grades 1-3 and transformed follicular lymphoma (FL)