Patterns of care in patients with muscle-invasive bladder cancer - a retrospective cohort study.

A potential reason for poor survival among patients with muscle-invasive bladder cancer (MIBC) in Poland is initial disqualification from curative treatment due to advanced stage of the disease or low performance status. The aim of this study was to describe patterns of care in patients with newly diagnosed MIBC. This is a multicentre retrospective cohort study involving 296 consecutive patients with primary histologically diagnosed MIBC. Therapeutic decisions and potentially underlying clinical factors were analysed. Full clinical data was available for 285 patients. One hundred and sixty-four (57.5%) patients were qualified for radical cystectomy (RC), 32 (11.2%) patients for a second step of transurethral resection of the bladder tumour (TURBT) intentionally followed by systemic chemotherapy, four (1.4%) patients after complete TURBT were qualified for adjuvant intravesical chemotherapy only, while the remaining 85 (29.8%) patients were qualified for palliative treatment in the form of chemotherapy and/or radiotherapy and/or best supportive care. Patients disqualified from curative treatment were older (78 vs. 69 years, p < 0.02), had lower BMI values (24.5 vs. 25.7 kg/m(2), p < 0.02), lower haemoglobin concentration (11.6 vs. 12.9 mg/l, p < 0.02), declared lower rate of nicotine abuse (50.5% vs. 72.1%, p < 0.02), and had a shorter time interval between first symptom and diagnosis (30 vs. 60 days, p = 0.02). As the majority of Polish patients with primary MIBC receive curative treatment, the stage of the disease alone seems not to be the leading cause of poor survival. However, appropriateness of qualification for RC and treatment quality needs to be assessed for final conclusion on the factors influencing outcomes of treatment in Poland.

CSN- and CAND1-dependent remodelling of the budding yeast SCF complex.

Cullin-RING ligases (CRLs) are ubiquitin E3 enzymes with variable substrate-adaptor and -receptor subunits. All CRLs are activated by modification of the cullin subunit with the ubiquitin-like protein Nedd8 (neddylation). The protein CAND1 (Cullin-associated-Nedd8-dissociated-1) also promotes CRL activity, even though it only interacts with inactive ligase complexes. The molecular mechanism underlying this behaviour remains largely unclear. Here, we find that yeast SCF (Skp1-Cdc53-F-box) Cullin-RING complexes are remodelled in a CAND1-dependent manner, when cells are switched from growth in fermentable to non-fermentable carbon sources. Mechanistically, CAND1 promotes substrate adaptor release following SCF deneddylation by the COP9 signalosome (CSN). CSN- or CAND1-mutant cells fail to release substrate adaptors. This delays the formation of new complexes during SCF reactivation and results in substrate degradation defects. Our results shed light on how CAND1 regulates CRL activity and demonstrate that the cullin neddylation-deneddylation cycle is not only required to activate CRLs, but also to regulate substrate specificity through dynamic substrate adaptor exchange.

Changes in the ratio of free NEDD8 to ubiquitin triggers NEDDylation by ubiquitin enzymes.

Ubiquitin and UBL (ubiquitin-like) modifiers are small proteins that covalently modify other proteins to alter their properties or behaviours. Ubiquitin modification (ubiquitylation) targets many substrates, often leading to their proteasomal degradation. NEDD8 (neural-precursor-cell-expressed developmentally down-regulated 8) is the UBL most closely related to ubiquitin, and its best-studied role is the activation of CRLs (cullin-RING ubiquitin ligases) by its conjugation to a conserved C-terminal lysine residue on cullin proteins. The attachment of UBLs requires three UBL-specific enzymes, termed E1, E2 and E3, which are usually well insulated from parallel UBL pathways. In the present study, we report a new mode of NEDD8 conjugation (NEDDylation) whereby the UBL NEDD8 is linked to proteins by ubiquitin enzymes in vivo. We found that this atypical NEDDylation is independent of classical NEDD8 enzymes, conserved from yeast to mammals, and triggered by an increase in the NEDD8 to ubiquitin ratio. In cells, NEDD8 overexpression leads to this type of NEDDylation by increasing the concentration of NEDD8, whereas proteasome inhibition has the same effect by depleting free ubiquitin. We show that bortezomib, a proteasome inhibitor used in cancer therapy, triggers atypical NEDDylation in tissue culture, which suggests that a similar process may occur in patients receiving this treatment.