Alberto Casabé

Human papillomavirus (HPV) DNA in penile carcinomas in Argentina: Analysis of primary tumors and lymph nodes

Among sexually transmitted diseases, infection by human papillomavirus (HPV) has become one of the most important. On the other hand, though epidemiological data show that some HPV types are closely associated with cervical cancer, few reports have been found with reference to penile carcinoma because of its rare occurrence. The aim of this study was to investigate the relationship between HPV infection and penile cancer in Argentina. A retrospective study was carried out on 38 white men with penile squamous‐cell carcinoma. Sixty‐five archival fixed biopsies taken from 34 primary penile tumors, 25 nodal metastases, 1 skin “satellite” metastasis and 5 histologically normal lymph nodes were used as specimens. HPV detection and typing were carried out by the polymerase chain reaction (PCR) using generic primers, combined with single‐stranded conformational polymorphism (SSCP) analysis. HPV DNA was found in 71% patients, corresponding 81% of them to “high risk” types, with predominance of HPV 18. Both primary tumors and metastases showed concordance of HPV occurrence and type in both lesions. In 3 patients, HPV 16 was detected not only in primary tumors and metastases, but also in histologically normal lymph nodes. Our data indicate that most penile carcinomas in Argentine patients are etiologically related to HPV, especially to “high risk” genital types. The agreement in HPV detection between primary tumors and metastases suggests a potential viral role in tumor progression. HPV detection in otherwise histologically normal lymph nodes might be useful as early marker of a metastatic process. J. Med. Virol. 61:65–69, 2000.

Novel invasive orthotopic bladder cancer model with high cathepsin B activity resembling human bladder cancer.

PURPOSE We developed and characterized an orthotopic invasive bladder tumor model. MATERIAL AND METHODS The MB49-I invasive bladder tumor cell line was obtained after 13 consecutive in vivo passages of primary tumor obtained by subcutaneous inoculation of MB49 bladder tumor cells in C57Bl/6J male mice. RESULTS MB49-I tumor local invasiveness, tumor weight and spontaneous metastatic capacity were higher than in MB49 tumors. In MB49-I bladder tumors increased vimentin was observed, suggesting epithelial mesenchymal transition. In vitro the MB49-I cell line showed higher invasive properties associated with an increase in cathepsin B, metalloproteinase 9 and urokinase-type plasminogen activator proteolytic activities. Orthotopic bladder tumors induced by electrocautery of the bladder wall and subsequent instillation of MB49 and MB49-I bladder cancer cells generated superficial and invasive bladder tumors, respectively. CONCLUSIONS The new murine bladder model described resembles human bladder disease, making it a useful tool for studying the molecular mechanisms of tumor progression and metastasis, and assaying antimetastatic and anti-invasive agents.

Bacillus Calmette Guerin Induces Fibroblast Activation Both Directly and through Macrophages in a Mouse Bladder Cancer Model

Background Bacillus Calmette-Guerin (BCG) is the most effective treatment for non-muscle invasive bladder cancer. However, a failure in the initial response or relapse within the first five years of treatment has been observed in 20% of patients. We have previously observed that in vivo administration of an inhibitor of nitric oxide improved the response to BCG of bladder tumor bearing mice. It was described that this effect was due to a replacement of tumor tissue by collagen depots. The aim of the present work was to clarify the mechanism involved in this process. Methodology/Principal Findings We demonstrated that BCG induces NIH-3T3 fibroblast proliferation by activating the MAPK and PI3K signaling pathways and also differentiation determined by alpha-smooth muscle actin (alpha-SMA) expression. In vivo, intratumoral inoculation of BCG also increased alpha-SMA and collagen expression. Oral administration of L-NAME enhanced the pro-fibrotic effect of BCG. Peritoneal macrophages obtained from MB49 tumor-bearing mice treated in vivo with combined treatment of BCG with L-NAME also enhanced fibroblast proliferation. We observed that FGF-2 is one of the factors released by BCG-activated macrophages that is able to induce fibroblast proliferation. The involvement of FGF-2 was evidenced using an anti-FGF2 antibody. At the same time, this macrophage population improved wound healing rate in normal mice and FGF-2 expression was also increased in these wounds. Conclusions/Significance Our findings suggest that fibroblasts are targeted by BCG both directly and through activated macrophages in an immunotherapy context of a bladder murine model. We also described, for the first time, that FGF-2 is involved in a dialog between fibroblasts and macrophages induced after BCG treatment. The fact that L-NAME administration improves the BCG effect on fibroblasts, NO inhibition, might represent a new approach to add to the conventional BCG therapy.

Inducible Nitric Oxide Synthase and PPARγ are Involved in Bladder Cancer Progression

PURPOSE We evaluated the role of inducible nitric oxide synthase and PPARγ as prognostic factors for bladder cancer. MATERIALS AND METHODS Inducible nitric oxide synthase and PPARγ were evaluated by Western blot and immunohistochemistry in a mouse bladder cancer model of nonmuscle invasive and invasive MB49-I tumor cells, and in human bladder cancer samples. RESULTS Inducible nitric oxide synthase expression was negative in mouse normal urothelium and higher in invasive than in noninvasive MB49 tumors. In vitro inducible nitric oxide synthase activity, determined as nitrite, was higher in MB49-I than in MB49 cells (p <0.001). In human samples expression was also associated with tumor invasion. Nuclear PPARγ expression was negative in normal mouse urothelium but higher in nonmuscle invasive MB49 than in MB49-I tumors. Similarly in human tumors low PPARγ was associated with poor prognosis factors, such as high histological grade (p = 0.0160) and invasion status (p = 0.0352). A positive correlation was noted between inducible nitric oxide synthase and PPARγ in low histological grade and nonmuscle invasive tumors (Pearson correlation index 0.6368, p = 0.0351, 0.4438 and 0.0168, respectively). As determined by gene reporter assay, PPARγ activity was induced by nitric oxide only in nonmuscle invasive MB49 cells (p <0.001). CONCLUSIONS Results suggest that increased PPARγ controls inducible nitric oxide synthase expression at early tumor stages. However, regulation is lost at advanced tumor stages, when the increase in inducible nitric oxide synthase and the decrease in PPARγ seem to be associated with bladder cancer progression.