Urine and Serum Exosomes as Novel Biomarkers in Detection of Bladder Cancer

Background: The gold standard for initial clinical diagnosis of bladder cancer involves cystoscopic examination of bladder and histological evaluation of tissues. There is a critical need to identify non-invasive and sensitive biomarkers. Early detection is essential challenge in diagnosis and surveillance of bladder carcinoma. Exosomes are nano- sized vesicles present in many biological fluids and have significant role in cancer. Thus, quantification of exosomes in different stages of bladder cancer may be of critical concern for clinical diagnosis and prognosis. Methods: Tumor derived exosomes levels in urine and serum samples of 70 bladder cancer Egyptian patients from stages T0-T3 and 12 healthy control people were measured using ELISA technique. Results: When compared to health subjects, exosomes levels in bladder cancer patients were increased in urine and serum samples at different stages of the disease. A gradual increase in tumor derived exosomes in serum (1.21, 3.31, 4.71, 6.47µg/ml) and urine (1.59, 2.84, 4.75, 6.67µg/ml) was observed comparative to invasiveness of tumor (T0-T3). Serum was more specific (100%) sample for detection of exosomes in bladder cancer. Conclusion:  our findings suggest that tumor derived exosomes may offer a convenient tool for early diagnosis and monitoring of bladder cancer.     

Drug specific cytotoxic T-cells in the skin lesions of a patient with toxic epidermal necrolysis

Toxic epidermal necrolysis is an extremely severe drug reaction, manifesting itself by widespread apoptosis of keratinocytes, generally considered to result from Fas/CD95-FasLigand interaction, but of unknown primary mechanism. We looked at the role of cells present in the skin blisters as probable effectors of this immune reaction. In a patient suffering from cotrimoxazole-induced toxic epidermal necrolysis, blister fluid cells were phenotyped by FACS and tested without prior restimulation for cytotoxicity on autologous and allogeneic cells in the presence of the drug. Blister fluid lymphocytes were predominantly CD8+, DR+, CLA+, CD56+ T lymphocytes, perforin positive and expressing preferentially two Vbeta chains of the T cell receptor repertoire. These lymphocytes were cytotoxic only in the presence of the drug towards autologous EBV transformed lymphocytes and towards allogeneic cells sharing HLA-Cw4. Cytotoxicity occurred in the presence of either cotrimoxazole, sulfamethoxazole, or the nitroso metabolite of sulfamethoxazole, but not with the hydroxylamine metabolite of sulfamethoxazole. The lysis was blocked by an anti-MHC class I monoclonal antibody. It was abolished by EGTA and CMA, but neither by anti-fas, brefeldin A, nor by anti-TRAIL receptor monoclonal antibodies, strongly suggesting perforin/granzyme-mediated cytotoxicity, without implication of Fas or TRAIL at this stage. This is direct evidence that T lymphocytes present within the lesions of toxic epidermal necrolysis may exhibit, without any re-stimulation, a drug-specific cytotoxicity against autologous cells. Harboring the markers of classical CTL and MHC class I restriction these lymphocytes reacted against the parent drug and one of its reactive metabolites. These results challenge several current concepts and could support new therapeutic approaches.     

Frequent PTEN genomic alterations and activated phosphatidylinositol 3-kinase pathway in basal-like breast cancer cells

Introduction

Basal-like carcinomas (BLCs) and human epidermal growth factor receptor 2 overexpressing (HER2+) carcinomas are the subgroups of breast cancers that have the most aggressive clinical behaviour. In contrast to HER2+ carcinomas, no targeted therapy is currently available for the treatment of patients with BLCs. In order to discover potential therapeutic targets, we aimed to discover deregulated signalling pathways in human BLCs.

Methods

In this study, we focused on the oncogenic phosphatidylinositol 3-kinase (PI3K) pathway in 13 BLCs, and compared it with a control series of 11 hormonal receptor negative- and grade III-matched HER2+ carcinomas. The two tumour populations were first characterised by immunohistochemistry and gene expression. The PI3K pathway was then investigated by gene copy-number analysis, gene expression profiling and at a proteomic level using reverse-phase protein array technology and tissue microarray. The effects of the PI3K inhibition pathway on proliferation and apoptosis was further analysed in three human basal-like cell lines.

Results

The PI3K pathway was found to be activated in BLCs and up-regulated compared with HER2+ tumours as shown by a significantly increased activation of the downstream targets Akt and mTOR (mammalian target of rapamycin). BLCs expressed significantly lower levels of the tumour suppressor PTEN and PTEN levels were significantly negatively correlated with Akt activity within that population. PTEN protein expression correlated significantly with PTEN DNA copy number and more importantly, reduced PTEN DNA copy numbers were observed specifically in BLCs. Similar to human samples, basal-like cell lines exhibited an activation of PI3K/Akt pathway and low/lack PTEN expression. Both PI3K and mTOR inhibitors led to basal-like cell growth arrest. However, apoptosis was specifically observed after PI3K inhibition.

Conclusions

These data provide insight into the molecular pathogenesis of BLCs and implicate the PTEN-dependent activated Akt signalling pathway as a potential therapeutic target for the management of patients with poor prognosis BLCs.     

Risk of renal and colonic neoplasms and spontaneous pneumothorax in the Birt-Hogg-Dubé syndrome.

The Birt-Hogg-Dubé syndrome, a genodermatosis characterized by benign tumors of the hair follicle, has been associated with renal and colonic neoplasms and spontaneous pneumothorax, but the risk of developing these disorders is unknown. We identified risk factors for renal tumors and spontaneous pneumothorax in 98 patients affected with the Birt-Hogg-Dubé syndrome, in 13 Birt-Hogg-Dubé haplotype carriers, and in 112 unaffected family members. Development of renal tumors was strongly associated with the Birt-Hogg-Dubé syndrome and age. The odds ratio for renal tumor in BHD-affected family members adjusted for age was 6.9 (95% confidence interval, 1.5-31.6) and approximately 9.0 for the other risk factors considered. Chromophobe renal carcinoma, an uncommon type of renal cancer, was the predominant type of renal cancer found. Spontaneous pneumothorax was also strongly associated with the Birt-Hogg-Dubé syndrome and age. The odds ratio for pneumothorax in BHD-affected individuals, adjusted for age, was 50.3 (95% confidence interval, 6.4-392), and about 32 times higher adjusting for the other risk variables. Colon cancer and colon polyps were not related to the Birt-Hogg-Dubé syndrome. The Birt-Hogg-Dubé syndrome confers an increased risk for the development of renal tumors and spontaneous pneumothorax. We found no increase in risk for the development of colon polyps or colon carcinomas.