Ricardo Ribeiro

Genetic Polymorphism in EGF Is Associated with Prostate Cancer Aggressiveness and Progression-Free Interval in Androgen Blockade–Treated Patients

Purpose: Most prostate cancer patients develop resistance to androgen deprivation treatment, resulting in hormone resistance. Epidermal growth factor (EGF) activates several pro-oncogenic intracellular pathways inducing proliferation, differentiation, and tumorigenesis in epithelial cells. The EGF-EGF receptor pathway seems to be especially relevant in hormone-resistant prostate cancer stage. A single nucleotide polymorphism G>A in +61 locus of EGF gene has been described, in which A homozygous carriers express significantly less EGF protein compared with G allele carriers. Our purpose was to investigate the potential prognostic and predictive role of EGF functional genetic variant +61 G>A in prostate cancer patients submitted to androgen blockade therapy (ABT). Experimental Design: We conducted a case-control study in prostate cancer patients treated with ABT (n = 123) and in healthy controls without evidence of cancer (n = 152). Cumulatively, a follow-up study (median follow-up, 37 months) was undertaken to evaluate response to ABT therapy in prostate cancer patients. EGF +61 G>A genotypes were detected by PCR-RFLP. Results: We found increased risk in G carriers, after age-adjusted regression analysis, for being diagnosed with Gleason ≥7 and with metastatic disease compared with control group (CG; age-adjusted odds ratio, 3.37, P = 0.004 and age-adjusted odds ratio, 2.61, P = 0.043, respectively). Kaplan-Meier survival analysis and log-rank test showed an influence of EGF +61 G>A polymorphism in time to relapse during ABT (P = 0.018). Conclusions:EGF functional polymorphism may contribute to earlier relapse in ABT patients, supporting the involvement of EGF as an alternative pathway in hormone-resistant prostatic tumors. Furthermore, our results lend support to EGF-EGF receptor pathway as an additional therapeutic target during hormonal treatment.

Hypoxia and Prostate Cancer Aggressiveness: A Tale With Many Endings

Angiogenesis, increased glycolysis, and cellular adaptation to hypoxic microenvironment are characteristic of solid tumors, including prostate cancer. These representative features are the cornerstone of cancer biology, which are well correlated with invasion, metastasis, and lethality, as well as likely with the success of prostate cancer treatment (eg, tumor hypoxia has been associated with resistance to chemotherapy and radiotherapy). It is well established that prostate cancer cells also metabolically depend on enhanced glucose transport and glycolysis for expansion, whereas growth is contingent with neovascularization to permit diffusion of oxygen and glucose. While hypoxia inducible factor 1 alpha (HIF-1α) remains the central player, the succeeding activated molecules and pathways track distinct branches, all positively correlated with the degree of intratumoral hypoxia. Among these, the vascular endothelial growth factor axis as well as the lysyl oxidase and carbonic anhydrase IX activities are notable in prostate cancer and merit further study. Here, we demonstrate their linkage with HIF-1α as a tentative explanatory mechanism of prostate cancer aggressiveness. Hypoxia drives a tale where HIF-1α-dependent effects lead to many influences in distinct key cancer biology features, rendering targeted therapies toward targets at the endings less efficient. The most appropriate approach will be to inhibit the upstream common driver (HIF-1α) activity. Additional translational and clinical research initiatives in prostate cancer are required to prove its usefulness.

Schistosoma haematobium: Identification of new estrogenic molecules with estradiol antagonistic activity and ability to inactivate estrogen receptor in mammalian cells

We have previously identified the expression of an estradiol (E2)-related molecule by Schistosoma haematobium total antigen (Sh). We now show that this molecule has an antagonistic effect of estradiol in vitro. Our results are consistent with the existence of an estrogenic molecule that antagonizes the activity of estradiol. We found evidence for this molecule as we identified and characterized by mass spectrometry new estrogenic molecules previously unknown, present in schistosome worm extracts and sera of Schistosoma-infected individuals. We also show that Sh is able to interact in vitro with estrogen receptor (ER), explaining how host endocrine system can favor the establishment of schistosomes. These findings highlight the exploitation of the host endocrine system by schistosomes and represent an additional regulatory component of schistosome development that defines a novel paradigm enabling host-parasite interactions. The identification of these molecules opens new ways for the development of alternative drugs to treat schistosomiasis.

Fatty Liver Characterization and Classification by Ultrasound

Steatosis , also known as fatty liver , corresponds to an abnormal retention of lipids within the hepatic cells and reflects an impairment of the normal processes of synthesis and elimination of fat. Several causes may lead to this condition, namely obesity, diabetes, or alcoholism. In this paper an automatic classification algorithm is proposed for the diagnosis of the liver steatosis from ultrasound images. The features are selected in order to catch the same characteristics used by the physicians in the diagnosis of the disease based on visual inspection of the ultrasound images. The algorithm, designed in a Bayesian framework, computes two images: i)a despeckled one, containing the anatomic and echogenic information of the liver, and ii) an image containing only the speckle used to compute the textural features. These images are computed from the estimated RF signal generated by the ultrasound probe where the dynamic range compression performed by the equipment is taken into account. A Bayes classifier, trained with data manually classified by expert clinicians and used as ground truth, reaches an overall accuracy of 95% and a 100% of sensitivity. The main novelties of the method are the estimations of the RF and speckle images which make it possible to accurately compute textural features of the liver parenchyma relevant for the diagnosis.

Hipoxia tumoral: Papel del factor inducible por hipoxia

HIF Hipoxia Cancer Los tumores solidos, por lo general, existen y progresan en un ambiente de hipoxia; asi se observa que las celulas tumorales son resistentes a la apoptosis y se acompanan de un aumento de la angiogenesis, volviendose mas agresivas, con capacidad invasora y resistentes al tratamiento. La genetica y los mecanismos biologicos subyacentes a este fenomeno son todavia poco claros, pero muchos estudios sugieren un papel del factor inducible por hipoxia (hipoxia inducible factor [HIF]) en este proceso. En condiciones de hipoxia, la subunidad alfa no es destruida y activara la transcripcion de un conjunto de genes que contribuyen a la agresividad del tumor. Su expresion esta asociada a un aumento del potencial metastasico que se verifica tanto en estudios animales, como en tumores humanos. La hipoxia tumoral se ha convertido en un factor clave en la progresion tumoral y se asocia a un mal pronostico, sobre todo en tumores de rinon y prostata. Este trabajo tiene por objetivo revisar la importancia de la hipoxia en la carcinogenesis y en la progresion tumoral, presentando una revision de los conocimientos actuales sobre el tema, mecanismos de accion y la activacion del HIF-1a.

Ovarian cancer and genetic susceptibility: association of A61G polymorphism in the EGF gene.

Growth factors play an essential role in regulating cellular proliferation, and lack of control is characteristic of malignant development. The epidermal growth factor (EGF) gene codifies a growth factor that binds to the EGF receptor (EGFR), which is involved in activating pathways that promote cellular proliferation, survival, migration and differentiation. The purpose of this study was to appraise the association between EGF gene A61G polymorphism with ovarian cancer susceptibility. A total of 564 DNA samples were analysed from 175 women with ovarian cancer and 389 women without cancer, through PCR-RFLP. We found a decreased risk for developing ovarian cancer in GG carriers compared to AA carriers (OR = 0.46, CI = 0.25–0.83, P = 0.010). The seemingly protective role in GG carriers was observed in women under 53 years of age (OR = 0.38, CI = 0.16–0.86, P = 0.011) and in patients diagnosed with advanced stage disease (OR = 0.38, CI = 0.18–0.81, P = 0.012). Allelic comparison evidenced similar results, with decreased risk for G allele. We further observed a linear trend for G allele in cancer risk. Moreover, we analysed the influence of genotypes in the time to onset of the disease and observed that GG carriers had ovarian cancer later than AA carriers (P = 0.035). We hypothesize that this polymorphism confers protection for ovarian cancer development.

Epidermal growth factor genetic variation, breast cancer risk, and waiting time to onset of disease.

Growth factors are important mediators of proliferation. Deregulation in growth factor mechanisms as well as in its receptors will contribute to cancer development. One of the most important is the epidermal growth factor (EGF), which is encoded by EGF gene. A functional polymorphism at position 61 (A/G) is associated with increased expression of EGF. Thus, we proposed to assess genotype frequencies in a case-control study and appraise their association to breast cancer risk. Using the polymerase chain reaction technique combined with restriction enzyme fragment length polymorphism (PCR-RFLP) we analyzed DNA from 883 women (500 controls and 383 breast cancer patients). Our results suggested that carriers of G homozygous genotype had a lower risk for developing breast cancer (odds ratio = 0.68; 95% confidence intervals, 0.46-1.01). Further, we showed that the waiting time for onset of breast cancer in G homozygous patients for EGF genotypes (55 years) was significantly lower in comparison to A-allele carriers (59 years) (log-rank test: p = 0.038). EGF is produced in mammary tissue and acts in the mammalian development. A lower risk for breast cancer in GG carriers might be explained through EGF receptor internalization promoted by EGF.

Classification and Staging of Chronic Liver Disease From Multimodal Data

Chronic liver disease (CLD) is most of the time an asymptomatic, progressive, and ultimately potentially fatal disease. In this study, an automatic hierarchical procedure to stage CLD using ultrasound images, laboratory tests, and clinical records are described. The first stage of the proposed method, called clinical based classifier (CBC), discriminates healthy from pathologic conditions. When nonhealthy conditions are detected, the method refines the results in three exclusive pathologies in a hierarchical basis: 1) chronic hepatitis; 2) compensated cirrhosis; and 3) decompensated cirrhosis. The features used as well as the classifiers (Bayes, Parzen, support vector machine, and k-nearest neighbor) are optimally selected for each stage. A large multimodal feature database was specifically built for this study containing 30 chronic hepatitis cases, 34 compensated cirrhosis cases, and 36 decompensated cirrhosis cases, all validated after histopathologic analysis by liver biopsy. The CBC classification scheme outperformed the nonhierachical one against all scheme, achieving an overall accuracy of 98.67% for the normal detector, 87.45% for the chronic hepatitis detector, and 95.71% for the cirrhosis detector.

Chronic liver disease staging classification based on ultrasound, clinical and laboratorial data

In this work the identification and diagnosis of various stages of chronic liver disease is addressed. The classification results of a support vector machine, a decision tree and a k-nearest neighbor classifier are compared. Ultrasound image intensity and textural features are jointly used with clinical and laboratorial data in the staging process.

Inactivation of estrogen receptor by Schistosoma haematobium total antigen in bladder urothelial cells

We recently reported the expression of an estradiol-like molecule by a trematode parasite Schistosoma haematobium. We further established that this estradiol-like molecule is an antagonist of estradiol, repressing the transcriptional activity of the estrogen receptor (ER) in estrogen-responsive MCF7 cells and also that S. haematobium total antigen (Sh) contains estrogenic molecules detected by mass spectrometry. In the present study, we used HCV29 cells, a cell line derived from normal urothelial cells, as well as an in vivo model to evaluate the expression of ER in the bladders of Sh-instilled animals. We show that, similarly to MCF7 cells, Sh down-regulates the transcriptional activity of ER in HCV29 cells and also in the bladders of Sh-treated mice. The antiestrogenic activity of the S. haematobium extract and its repressive role in ER could have implications in the carcinogenic process in bladders with S. haematobium infection.