Early response to ErbB2 over-expression in polarized Caco-2 cells involves partial segregation from ErbB3 by relocalization to the apical surface and initiation of survival signaling.

In several human cancers, ErbB2 over-expression facilitates the formation of constitutively active homodimers resistant to internalization which results in progressive signal amplification from the receptor, conducive to cell survival, proliferation, or metastasis. Here we report on studies of the influence of ErbB2 over-expression on localization and signaling in polarized Caco-2 and MDCK cells, two established models to study molecular trafficking. In these cells, ErbB2 is not over-expressed and shares basolateral localization with ErbB3. Over-expression of ErbB2 by transient transfection resulted in partial separation of the receptors by relocalization of ErbB2, but not ErbB3, to the apical surface, as shown by biotinylation of the apical or basolateral surfaces. These results were confirmed by immunofluorescence and confocal microscopy. Polarity controls indicated that the relocalization of ErbB2 is not the result of depolarization of the cells. Biotinylation and confocal microscopy also showed that apical, but not basolateral ErbB2 is activated at tyrosine 1139. This phosphotyrosine binds adaptor protein Grb2, as confirmed by immunoprecipitation. However, we found that it does not initiate the canonical Grb2-Ras-Raf-Erk pathway. Instead, our data supports the activation of a survival pathway via Bcl-2. The effects of ErbB2 over-expression were abrogated by the humanized anti-ErbB2 monoclonal antibody Herceptin added only from the apical side. The ability of apical ErbB2 to initiate an altered downstream cascade suggests that subcellular localization of the receptor plays an important role in regulating ErbB2 signaling in polarized epithelia.

Epithelial-mesenchymal transition, proliferation, and angiogenesis in locally advanced cervical cancer treated with chemoradiotherapy.

We evaluated the association between epithelial-mesenchymal transition (EMT)-derived markers and expression of proteins associated with cell proliferation and tumor growth, as well as their prognostic roles, in 61 patients (mean age 52 ± 10 years) with locally advanced cervical cancer, all of whom were treated with chemoradiation and intracavitary brachytherapy. We used immunohistochemical analysis to assess the expression of proteins targeted in our investigation. Various statistical analyses were then conducted to assess protein marker associations with survival outcomes. Forty-six percent of the patients were positive for human papilloma virus. Median progression-free survival (PFS) was 6.6 months (95% confidence interval [CI]: 4.0-9.1, whereas overall survival (OS) was 30.0 months (95% CI: 11-48). Multivariate analysis demonstrated that vascular endothelial growth factor (VEGF) (P = 0.002), epidermal growth factor receptor (EGFR) (P = 0.001), and TWIST2 (P = 0.001) expression levels, as well as a tumor size <6 cm (P = 0.02), influenced OS. Changes in TWIST2 levels and loss of E-cadherin expression were correlated with VEGF and EGFR levels; furthermore, patients with high TWIST2 expression had shorter OS (P = 0.0001), as those with loss of E-cadherin (P = 0.02). OS was even shorter when positive EGFR or VEGF expression was related with EMT markers (positive EGFR + negative E-cadherin: median 14 months, 95% CI: 3-24; negative EGFR + positive E-cadherin: median 31 months, 95% CI: 14-NA; P = 0.02.). The presence of EMT markers was associated with proliferative and pro-angiogenic protein expression and influenced the prognosis of locally advanced cervical cancer.

Valor pronóstico de la densidad microvascular y de la expresión del VEGF, EGFR y HIF-1α en pacientes con cáncer de cérvix localmente avanzado tratados con quimiorradiación (ONCOLGroup)§ / Prognostic value of microvascular density and expression of VEGF, EGFR and HIF-1α in patients with locally advanced cervical cancer treated with chemoradiation (ONCOLGroup)§

Introducción: en Colombia el carcinoma de cuello uterino representa la segunda causa de muerte por cáncer entre las mujeres. Objetivo: describir el valor pronóstico de la densidad microvascular (DMV) y de la expresión proteica de varios genes relacionados con la supervivencia y proliferación del cáncer de cérvix localmente avanzado tratado con quimiorradiación/braquiterapia intracavitaria. Se estimaron la tasa de respuesta global (TRG), la supervivencia libre de progresión (SLP) y la supervivencia global (SG). Resultados: se incluyeron 61 mujeres con una edad media de 52 ± 10 años; todas tenían diagnóstico de cáncer de cérvix localmente avanzado (IIA 2.3%/IIB 47.5%/IIIA 4.9%/IIIB 37.7%/IVA 3.3%/no definido 3.3%), con un volumen tumoral promedio de 6.4cm (DE± 1.8cm) e infección por VPH en 46% de los casos; 58 sujetos (95%) tenían un patrón escamoso, dos fueron adenocarcinomas y >50% presentaba neoplasias moderada o pobremente diferenciadas. Todas fueron tratadas con quimiorradiación (interrupción transitoria de la teleterapia por toxicidad y otras causas en 19 y 21.4%, respectivamente/media de ciclos de platino concomitante 4.8 series ± 1.0) y braquiterapia (77% completaron el tratamiento intracavitario). La mediana para la SLP y global fue de 6.6 meses (4.0-9.1) y 30 meses (1148), respectivamente. Ninguna de las variables tuvo efecto sobre la SLP, mientras el análisis multivariado demostró que los niveles de expresión del VEGF (p=0.026), EGFR (p=0.030), y el volumen tumoral <6 cm (p=0.02) influyeron sobre este desenlace. Conclusión: la tipificación de genes relacionados con angiogénesis y proliferación celular en el cáncer de cérvix localmente avanzado tratado con quimiorradiación basada en platino tiene una influencia positiva sobre el pronóstico. (Acta Med Colomb 2012; 37: 106-117).

Introduction: cervical carcinoma is the second leading cause of cancer death among women in Colombia. Objective: to describe the prognostic value of microvascular density (MVD) and protein expression of several genes related to survival and proliferation of locally advanced cervical cancer (LACC) treated with chemoradiation / intracavitary brachytherapy. We estimated the overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). Results: we included 61 women with a mean age of 52 ± 10 years; all were diagnosed with locally advanced cervical cancer (IIA 2.3% / IIB 47.5% / IIIA 4.9% / IIIB 37.7% / IVA 3.3% / 3.3% undefined ), with an average tumor volume of 6.4cm (SD ± 1.8cm) and HPV infection in 46% of cases. 58 subjects (95%) had a squamous pattern; two were adenocarcinomas and >50% had moderate or poorly differentiated neoplasms. All were treated with chemoradiation (temporary interruption of teletherapy due to toxicity, and other causes was documented in 19% and 21.4% respectively / mean of concomitant platinum cycles 4.8 ± 1.0) and brachytherapy (77% completed intracavitary treatment). The median PFS and OS was 6.6 months (4.0-9.1) and 30 months (11-48), respectively. None of the variables had an effect on the PFS, while multivariate analysis demonstrated that the levels of VEGF expression (p = 0.026), EGFR (p = 0.030), and tumor volume <6 cm (p = 0.02) influenced this outcome. Conclusion: the characterization of genes related to angiogenesis and cell proliferation in locally advanced cervical cancer treated with platinum-based chemoradiation had a positive influence on the prognosis. (Acta Med Colomb 2012; 37: 106-117).

Braquiterapia de alta tasa como refuerzo a la radioterapia externa en pacientes con carcinoma de próstata de pronóstico desfavorable / High Ratio Brachytherapy to Reinforce External Radiotherapy in Patients with Prostate Carcinoma of Unfavorable Prognosis

La relativa alta tasa de recaída local en los pacientes con carcinoma de próstata de pronóstico desfavorable tratados con radioterapia externa convencional se debe en parte a factores relacionados con el tumor y en parte a factores técnicos[1, 2]. El tratamiento óptimo para el carcinoma de próstata de pronóstico desfavorable continúa generando controversia en parte por la gran variedad de definiciones de categorías de riesgo en este grupo de pacientes. En la actualidad se sabe que la graduación histológica con la escala cualitativa de Gleason y los niveles séricos pretratamiento del antígeno prostático específico tienen valor predictivo en cuanto a la posibilidad de enfermedad extra-prostática, compromiso de vesículas seminales y metástasis pélvicas ganglionares, siendo indicadores de mal pronóstico los pacientes con Gleason mayor o igual a 7 y niveles de antígeno prostático específico (PSA) mayor o igual a 10 ng/ml.

Radiocirugía: principios y aplicaciones en la práctica clínica

En los últimos años, la introducción de la radiocirugía, en combinación con la microneurocirugía y la neurorradiología intervencionista, ha hecho posible eltratamiento eficaz, de patologías de tipo vascular y tumoral al igual que trastornos funcionales, hasta hace poco intratables o tratables a costa de una elevada morbimortalidad para el paciente. En el presente artículo se hace una revisión de los conceptos básicos de física y radioterapia que debe conocer el médico para tener acceso en forma lógica y segura a esta tecnología. Se revisan las opciones de tratamiento con radiocirugía disponibles hoy día, sus indicaciones, resultados y efectos colaterales. El tema tratado posee enorme importancia para los médicos en general ya que desde hace poco esta tecnología ya está disponible en el país.