Céu Costa

Ki-67 index enhances the prognostic accuracy of the urothelial superficial bladder carcinoma risk group classification.

Approximately 80% of bladder tumors are urothelial superficial papillary carcinomas (USPC). Despite a generally good prognosis, these tumors have a strong propensity to recur and about 1/3 of them compared to disease progression. Histological assessment of these superficial tumors is not sufficiently discriminator in predicting prognosis; therefore, we decided to evaluate the prognostic significance of p53 and Ki‐67 immunoexpression in low‐grade (GI‐II) USPC in order to predict the potential outcome of these tumors. P53 and Ki‐67 immunoexpression were studied in function of recurrence‐free and progression‐free survival in 159 primary superficial bladder tumors. A prognostic risk model based on grade, stage and multifocality was also evaluated. P53 accumulation was significantly related to tumor progression (p=0.006). High Ki‐67 index (≥18%) and multifocality were significantly related to recurrence (both p=0.0001) and progression‐free survival (both p=0.0001) and were independent prognostic factors in the multivariate analysis. The prognostic risk model based on grade, stage and multifocality was not an efficient discriminator of outcome. Adding the Ki‐67 index into the risk model, single pTa/T1‐GI Ki‐67 positive tumors, usually classified as low risk, were reclassified as of intermediate risk. After this reclassification, the risk group model identified a subgroup of pTa/T1‐G1 with a high risk of recurrence and progression. Ki‐67 index is a reliable prognostic marker in urothelial superficial bladder carcinoma and, when included into a risk profile classification of the low‐grade USPC, the accuracy of the prognostic discrimination is enhanced.

Overexpression of tumour-associated carbohydrate antigen sialyl-Tn in advanced bladder tumours

Little is known on the expression of the tumour‐associated carbohydrate antigen sialyl‐Tn (STn), in bladder cancer. We report here that 75% of the high‐grade bladder tumours, presenting elevated proliferation rates and high risk of recurrence/progression expressed STn. However, it was mainly found in non‐proliferative areas of the tumour, namely in cells invading the basal and muscle layers. STn was also found in tumour‐adjacent mucosa, which suggests its dependence on a field effect of the tumour. Furthermore, it was not expressed by the normal urothelium, demonstrating the cancer‐specific nature of this antigen. STn expression correlated with that of sialyltransferase ST6GalNAc.I, its major biosynthetic enzyme. The stable expression of ST6GalNAc.I in the bladder cancer cell line MCR induced STn expression and a concomitant increase of cell motility and invasive capability. Altogether, these results indicate for the first time a link between STn expression and malignancy in bladder cancer. Hence, therapies targeting STn may constitute new treatment approaches for these tumours.

Bladder cancer-induced skeletal muscle wasting: disclosing the role of mitochondria plasticity.

Loss of skeletal muscle is a serious consequence of cancer as it leads to weakness and increased risk of death. To better understand the interplay between urothelial carcinoma and skeletal muscle wasting, cancer-induced catabolic profile and its relationship with muscle mitochondria dynamics were evaluated using a rat model of chemically induced urothelial carcinogenesis by the administration of N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN). The histologic signs of non-muscle-invasive bladder tumors observed in BBN animals were related to 17% loss of body weight and high serum levels of IL-1β, TNF-α, TWEAK, C-reactive protein, myostatin and lactate and high urinary MMPs activities, suggesting a catabolic phenotype underlying urothelial carcinoma. The 12% loss of gastrocnemius mass was related to mitochondrial dysfunction, manifested by decreased activity of respiratory chain complexes due to, at least partially, the impairment of protein quality control (PQC) systems involving the mitochondrial proteases paraplegin and Lon. This was paralleled by the accumulation of oxidatively modified mitochondrial proteins. In overall, our data emphasize the relevance of studying the regulation of PQC systems in cancer cachexia aiming to identify therapeutic targets to counteract muscle wasting.

Abnormal Protein Glycosylation and Activated PI3K/Akt/mTOR Pathway: Role in Bladder Cancer Prognosis and Targeted Therapeutics.

Muscle invasive bladder cancer (MIBC, stage ≥T2) is generally associated with poor prognosis, constituting the second most common cause of death among genitourinary tumours. Due to high molecular heterogeneity significant variations in the natural history and disease outcome have been observed. This has also delayed the introduction of personalized therapeutics, making advanced stage bladder cancer almost an orphan disease in terms of treatment. Altered protein glycosylation translated by the expression of the sialyl-Tn antigen (STn) and its precursor Tn as well as the activation of the PI3K/Akt/mTOR pathway are cancer-associated events that may hold potential for patient stratification and guided therapy. Therefore, a retrospective design, 96 bladder tumours of different stages (Ta, T1-T4) was screened for STn and phosphorylated forms of Akt (pAkt), mTOR (pmTOR), S6 (pS6) and PTEN, related with the activation of the PI3K/Akt/mTOR pathway. In our series the expression of Tn was residual and was not linked to stage or outcome, while STn was statically higher in MIBC when compared to non-muscle invasive tumours (p = 0.001) and associated decreased cancer-specific survival (log rank p = 0.024). Conversely, PI3K/Akt/mTOR pathway intermediates showed an equal distribution between non-muscle invasive bladder cancer (NMIBC) and MIBC and did not associate with cancer-specif survival (CSS) in any of these groups. However, the overexpression of pAKT, pmTOR and/or pS6 allowed discriminating STn-positive advanced stage bladder tumours facing worst CSS (p = 0.027). Furthermore, multivariate Cox regression analysis revealed that overexpression of PI3K/Akt/mTOR pathway proteins in STn+ MIBC was independently associated with approximately 6-fold risk of death by cancer (p = 0.039). Mice bearing advanced stage chemically-induced bladder tumours mimicking the histological and molecular nature of human tumours were then administrated with mTOR-pathway inhibitor sirolimus (rapamycin). This decreased the number of invasive lesions and, concomitantly, the expression of STn and also pS6, the downstream effector of the PI3K/Akt/mTOR pathway. In conclusion, STn was found to be marker of poor prognosis in bladder cancer and, in combination with PI3K/Akt/mTOR pathway evaluation, holds potential to improve the stratification of stage disease. Animal experiments suggest that mTOR pathway inhibition could be a potential therapeutic approach for this specific subtype of MIBC.

Everolimus combined with cisplatin has a potential role in treatment of urothelial bladder cancer.

Cisplatin (CDDP)-based chemotherapy is a commonly treatment for advanced urothelial carcinoma. However, episodes of cisplatin resistance have been referenced. Recently it has been reported that everolimus (RAD001) could have an important role to play in bladder-cancer treatment and that mTOR inhibitors may restore chemosensitivity in resistant tumours. The aim of this study was to assess RAD001 in vitro ability to enhance CDDP cytotoxicity in three human bladder-cancer cell lines. Over the course of 72h, the cells were exposed to different concentrations of CDDP and RAD001, isolated or combined. Treatment with CDDP statistically (P<0.05) decreased cell proliferation in cell lines in a dose-dependent manner. The anti-proliferative activity of CDDP used in combination with RAD001 was statistically significant (P<0.05) in the cell lines at all concentrations tested. RAD001 had a therapeutic effect when used in combination with CDDP and could therefore be a useful anti-cancer drug combination for patients with bladder cancer.

Patient-derived bladder cancer xenografts: a systematic review

Patient-derived tumor xenografts (PDTXs) are said to accurately reflect the heterogeneity of human tumors. In the case of human bladder cancer, few studies are available featuring these models. The best methodology to develop and the real value of the model remain unclear. This systematic review aims to elucidate the best methodology to establish and use PDTXs to study the characteristics and behavior of human bladder tumors. The value and potential application of these models are also addressed. A comprehensive literature search was performed to identify published studies using xenograft models directly established from human bladder cancer samples into mice. A total of 12 studies were included in the final analysis. All studies differed in design; the reported take rate varied between 11% and 80%, with the implantation via dorsal incision and with matrigel obtaining the higher take rate. Advanced stage and high-grade tumors were associated with increased take rate. Xenografts preserved the original tumor identity in the establishment phase and after serial passages. Although some studies suggest a correlation between engraftment success and clinical prognosis, evidence about the association between the response of xenografts to treatment and the clinical response of the tumor of origin is still missing. All methodological approaches resulted in the establishment of tumor xenografts with preservation of the original tumor identity but variable take rate. The time needed to establish the model and propagate xenografts to a number suitable for drug testing is the main limitation of the model, along with the success rate and lack of consistency in the early passages. Comparison between tumor response in mice and clinical outcome remains to be assessed.

The prognostic value of MDM2 overexpression in superficial urothelial bladder carcinoma

The prognostic significance of p53 accumulation and MDM2 overexpression in superficial and papillary urothelial cell carcinoma (UCC) of the bladder has not yet been established. Therefore, MDM2 and p53 protein were investigated focusing on tumour grade and muscularis mucosae invasion in order to identify their prognostic significance. Thirty-five archival UCC were studied by immunohistochemistry using monoclonal antibodies DO7 against p53, and IB10 against MDM2. MDM2 overexpression was observed in 51.4% of the cases. The recurrence rate for patients with MDM2 overexpression was 7.09 fold higher than for those without MDM2 overexpression. p53 accumulation was not related to prognosis. There was no significant difference between low and high grade tumours in regard to MDM2 overexpression and p53 accumulation. pTa cases presented the higher frequency of MDM2 positive cases (66.7%) and a lower frequency of p53 accumulation (33.3%). MDM2 overexpression does not seem to be related to muscular mucosae invasion. Thus, MDM2 status may well be a prognostic marker in superficial urothelial bladder carcinomas.ResumenEl significado pronóstico de la expresión aumentada de MDM2 y de la acumulación de p53 en carcinomas de células uroteliares superficiales y papilares (UCC) de la vejiga no está totalmente esclarecido. Es importante, portanto, investigar la presencia de las proteínas MDM2 y p53 en función del grado y de la invasión de la lámina propia en estos tumores con el fin de identificar su significado pronóstico.Se ha estudiado material de archivo de 35 UCC mediante imunohistoquímica utilizando el anticuerpo monoclonal DO7 para p53 y el IB10 para MDM2.Se observó una expresión aumentada de MDM2 en el 51,4% de los casos, encontrándose correlación con la tasa de recurrencia y de supervivencia libre de recurrencia. La acumulación nuclear de p53 no fue relacionada con el pronóstico. Estos marcadores no distinguieron significativamente los tumores superficiales de alto y bajo grado. Se encontró que los casos de estadio pTa eran los que presentaban una mayor frecuencia de sobreexpresión para la MDM2 (66,7%) mientras que estos casos tenían la menor frecuencia de acumulación de p53 (33,3%). Aparentemente la sobreexpresión de MDM2 no está relacionada con la invasión de la muscularis mucosae.El análisis de MDM2 parece ser un marcador pronóstico en carcinomas uroteliares superficiales de vejiga.