Safety and effectiveness of vinflunine in patients with metastatic transitional cell carcinoma of the urothelial tract after failure of one platinum-based systemic therapy in clinical practice

BACKGROUND: Patients with transitional cell carcinoma of the urothelial tract (TCCU) who fail initial platinum-based chemotherapy for advanced disease represent a challenge in daily clinical practice. Vinflunine is approved by the European Medicine Agency (EMA) but, up to now, limited experience has been reported outside clinical trials. METHODS: We assessed the efficacy and safety of vinflunine in an unselected group of 102 consecutive patients with metastatic TCCU. RESULTS: The median age was 67 years (range 45–83). Among the most common comorbidities that patients presented at baseline were hypertension (50.5%) and diabetes (20.7%). Distant metastases were present in retroperitoneal nodes (58%), lung (29.3%), and bone (20.2%). The ECOG 0, 1 and 2 performance status at the start of vinflunine were 31.3%, 60.6% and 8.1%, respectively. The most commonly reported adverse events of any grade were constipation 70.6% (5.9% grade 3–4), vomiting 49.1% (2% grade 3–4), neutropenia 48.1% (12.8% grade 3–4) and abdominal pain 34.3% (4.9% grade 3–4). A median of 4 cycles of vinflunine was administered per patient (range 1–18). Median progression free and overall survival for all patients (N = 102) were 3.9 months (2.3-5.5) and 10 months (7.3-12.8), respectively. Time to tumor progression was 4.3 months (2.6-5.9). Two patients (2%) achieved CR, 23 (22.5%) patients had PR, and 42 (41.2%) presented SD as best response. The clinical benefit rate with vinflunine was 65.7%. CONCLUSIONS: Our results show that the behavior of vinflunine in routine clinical practice resembles that of the pivotal phase III randomized study

Microtubule-targeted agents: When mitochondria become essential to chemotherapy

AbstractMicrotubule-Targeting Agents (MTAs) constitute a class of drugs largely used for cancer treatment in adults and children. In cancer cells, they suppress microtubule dynamics, and induce cell death via the mitochondrial intrinsic pathway. To date, links between mitochondria and microtubule network disturbance in MTAs mechanism of action are not obvious. The aim of the present contribution is to provide elements that could answer to the question: how far are mitochondria essential to anticancer chemotherapy that targets the microtubule cytoskeleton? We review the main molecular candidates to link microtubule alteration with the apoptotic mitochondrial pathway control. Involvement of direct targeting of mitochondria in MTA efficacy is also discussed. Furthermore, we line up current evidence and emerging concepts on the participation of both mitochondria and microtubule in MTA neurotoxic side effects. To decipher the interconnections between the mitochondrial and the microtubule networks may help to improve cancer cell response to chemotherapy. This article is part of a Special Issue entitled: Bioenergetics of Cancer

Microtubules in Apoptosis Induction: Are They Necessary?

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P11.06 Non epigenetic effect of vorinostat in glioblastoma cells

Abstract BACKGROUND Glioblastoma multiform (GBM) is the most frequent primitive brain tumor. GBM has a high recurrence and mortality. Histone deacetylase (HDAC) inhibitors have evoked great interest because they are able to change transcriptomic profiles to promote tumor cell death but also show undesirable side effects due to the lack of selectivity.We show new properties of low dose vorinostat, which inhibits cytoplasmic HDAC6 and display interesting non-epigenetics effects, especially on the microtubular cytoskeleton. MATERIAL AND METHODS We used murine (GL261) and human (U87 and GBM6 stem cells) cellular models. The cell proliferation was assessed by MTT tests, the migration by the 24 hours Transwell technic and by wound/healing tests. The expression levels of proteins of interest were assessed by Western Blot. Microtubules dynamics were assessed by time-lapse videomicroscopy. The synergy between drugs was tested by Loewe model. RESULTS Vorinostat inhibited the proliferation and the migration of the three cell lines mentioned above at level below the EC50.Vorinostat induces tubulin acetylation and alpha-tubulin c-terminal detyrosination that signed microtubular stabilization and these effects are independent of histone acetylation (HADC3). Interestingly, vorinostat decreases EB1 expression (a bad prognostic factor in GBM) and decreases microtubule dynamics. Moreover, vorinostat decreases neural markers such as GFAP, beta3-tubulin and CNPase and increases mural markers expression such as SMA/EGFR and PDGFR. Finally, it showed a synergy combined with erlotinib. CONCLUSION Low dose vorinostat, which do not affect histone désacetylase, has antitumor effect on glioblastoma cells by a new mechanism involving microtubule cytoskeleton. Interestingly, combination of low doses vorinostatand erlotinibshowed a strong synergy. Low dose, vorinostat could therefore represent an interesting therapeutic option and fewer side effects and that could be used to increased GBM patient sensitivity to erlotinib. </jats:sec

RESTORATION BY BIOTIN OF THE INVITRO MICROTUBULE FORMATION INHIBITED BY UREMIC TOXINS

Tubulin is an intracellular protein whose in vivo polymerization leads to the formation of microtubules (MT). MT are an essential component of axons of nerve cells. This reaction is the limiting factor in the growth of axons. Uremic neuropathy is characterized in part by an axonal degeneration. A chromatographic fraction from uremic plasma (2-5 fraction) inhibits in vitro the tubulin polymerization and thus MT formation and therefore may be implicated in the occurrence of uremic neuropathy. In vitro, biotin counteracts the inhibitory effect of 2-5 fraction on MT formation. This effect could be a partial explanation of the possible clinical improvement brought on by biotin in uremic neuropathy

Patupilone-Induced Apoptosis Is Mediated by Mitochondrial Reactive Oxygen Species through Bim Relocalization to Mitochondria

International audienceAmong the new microtubule-targeted agents, the epothilone family of molecules has shown promising anticancer potential, and clinical trials are currently underway for patupilone (epothilone B) in various cancer indications. In this study, we characterized novel aspects of patupilone's cellular action that may underlie its potent cytotoxicity in human neuroblastoma cells. Patupilone induced mitochondrial membrane potential collapse, mitochondrial morphological changes, and cytochrome c release, leading to apoptosis. Within the first 2 h, patupilone increased the generation of reactive oxygen species (ROS; i.e., superoxides and hydrogen peroxide, 33+/-6 and 51+/-3% increase, respectively), specifically from mitochondria. ROS scavengers and mitochondrial DNA depletion [rho(-) cells] significantly protected cells against patupilone cytotoxicity, indicating that ROS generation is a key event in the initial phase of apoptosis. Although the Bim expression level was not modified by patupilone, this proapoptotic protein accumulated in the mitochondrial compartment (2.4-fold increase at IC70) after only a 6-h treatment. In contrast, Bax and Bcl-2 mitochondrial levels were not changed during treatment. It is noteworthy that ROS inhibition prevented Bim relocalization to mitochondria and mitochondrial membrane changes induced by patupilone. Altogether, our data reveal that patupilone-mediated ROS production by mitochondria initiates the intrinsic signaling cascade by inducing Bim accumulation in mitochondria. These results might explain the superior activity of patupilone in tumor cells compared with paclitaxel that is, until now, the clinical reference among microtubule-stabilizing agents. Furthermore, our data highlight the importance of mitochondria that simultaneously assume the role of activator and integrator of apoptotic signals triggered by patupilone

Organic Nanoparticles as Anticancer and Theranostic Devices

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