MDM2 promotes cell motility and invasiveness through a RING-finger independent mechanism.

Recent studies connect MDM2 with increased cell motility, invasion and/or metastasis proposing an MDM2-mediated ubiquitylation-dependent mechanism. Interestingly, in renal cell carcinoma (RCC) p53/MDM2 co-expression is associated with reduced survival which is independently linked with metastasis. We therefore investigated whether expression of p53 and/or MDM2 promotes aggressive cell phenotypes. Our data demonstrate that MDM2 promotes increased motility and invasiveness in RCC cells (N.B. similar results are obtained in non-RCC cells). This study shows for the first time both that endogenous MDM2 significantly contributes to cell motility and that this does not depend upon the MDM2 RING-finger, i.e. is independent of ubiquitylation (and NEDDylation). Our data suggest that protein-protein interactions provide a likely mechanistic basis for MDM2-promoted motility which may constitute future therapeutic targets.

The '2-week wait' rule for referrals for suspected urological cancers--urgent need for refinement of criteria.

INTRODUCTION: All NHS-suspected cancers should be seen within 2 weeks of referral and are referred under government guidelines (Health Service Circular 205; HSC 205). This policy will be subject to review in 2009. Review is vital to allow the appropriate detection of malignancy without overburdening the premium clinic slots with the healthy. PATIENTS AND METHODS: A total of 170 consecutive patients were referred from January-June 2005. Referral details, patient information, events and time to diagnosis were recorded. RESULTS: Of these 170 patients, 143 were suitable for analysis. Forty-three patients (30%) were referred with frank haematuria, of whom 30% had bladder cancer. Nine percent of patients (n = 13) had microscopic haematuria none of whom had cancer. A quarter of the patients (n = 35) were referred with suspected testis cancer but none had cancer. Forty-one patients were referred with serum prostate-specific antigen (PSA) elevation; 18 cancers were detected in this group. Ten men had PSA values greater than 50 ng/ml. Only two cancers were suitable for radical prostatectomy. No cancer was found in patients less than 50 years of age. CONCLUSIONS: A high cancer incidence was found (27.9%), the majority of which was bladder cancer or advanced prostate cancer. Out of the 143 patients, no malignancy was diagnosed in any patient less than 50 years of age, no malignancy was diagnosed in any of the microscopic haematuria group and there was no cancer diagnosed in the group of patients referred with scrotal swellings. We suggest that some guidelines are leading to referral of patients with low cancer risk. When the HSC 205 is revised in 2009, we hope studies such as ours are taken into consideration in order to improve resource utilisation.

p53 regulation and function in renal cell carcinoma.

Loss of p53 function is a critical event in tumor evolution. This occurs through a range of molecular events, typically a missense p53 mutation followed by loss of heterozygosity. In many cancers, there is compelling evidence that cells that can compromise p53 function have a selective advantage. The situation in renal cell carcinoma is unclear. It has recently been suggested that p53 function is unusually compromised in renal carcinoma cells by a novel dominant, MDM2/p14ARF-independent mechanism. This is hard to reconcile with other recent studies that have identified p53 as an important prognostic indicator. Indeed, one of these latter studies found that the best predictor of poor outcome was the presence of high levels of both p53 (usually indicative of p53 mutation) and MDM2. Thus, it is important that we gain a clearer understanding of the regulation of p53 and the role of MDM2 in renal cell cancer. To address this, we have investigated the transcriptional activity of p53 in a panel of renal cell carcinoma cell lines and the contribution of MDM2 and p14ARF to p53 regulation. We have found that p53 is functional in p53 wild-type renal cell carcinoma cells and that this activity is significantly regulated by MDM2 and to a much lesser extent by p14ARF. Moreover, following induction of DNA damage with UV, the p53 response in these cells is intact. Thus, future studies of renal cell carcinoma that focus on p53 and MDM2 and their role in determining disease outcome will be required to create a better understanding of this notoriously difficult to manage disease.