In vitro modeling of HER2-targeting therapy in disseminated prostate cancer.

Prostate cancer (PCa) is the most common cancer type among men. Treatments against advanced PCa are limited and in many cases only palliative. In a later, androgent independent, stage of PCa androgen receptors can be activated without interaction with ligand, i.e., by receptors of tyrosine kinase (RTK) family in the outlaw pathway. Human epidermal growth factor receptors HER2 and EGFR belong to RTK-family. HER2 is one of the main actors in the outlaw pathway with EGFR as the preferable heterodimerizing partner. We hypothesized that information on HER2 expression in advanced PCa could be useful for selection of patients for anti-RTK therapy and monitoring of therapy response. A panel of PCa cell lines (LNCap, PC3, DU-145) was subjected to a 8-week treatment using drugs influencing the RTK: trastuzumab (anti­HER2), 17-DMAG (Hsp90 inhibitor), alone or in combination, and their HER2 and EGFR expressions were compared with non-treated cells. Treatment with trastuzumab decreased proliferation of LNCap and DU-145 cell lines, while 17-DMAG and trastuzumab/17­DMAG combination affected all three cell lines. HER2 expression was significantly increased in PC3 cells, the most resistant cell line. On the contrary, in responding cells (LNCap and DU-145) HER2 expression decreased, accompanied by increased EGFR expression. However, additional treatment of cells with cetuximab (anti­EGFR) did not give any additive effect to trastuzumab. In this study the response to anti-RTK therapy proved to vary between different PCa cell lines. We have demonstrated that RTK targeting treatments may affect the phenotypic profile of PCa tumor cells that correlates with therapy outcome. Observation of such changes during treatment could be used for monitoring and an improved therapy outcome.

An overview on preclinical and clinical experiences with photodynamic therapy for bladder cancer.

Photodynamic therapy (PDT) is one of the most interesting methods of photo treatment. In general, PDT is a modality for the treatment of non-muscle invasive tumors. PDT is very well suited in managing bladder cancer, as the bladder is accessible by endoscopy and the tumors are most often limited to the mucosa or sub-mucosa. PDT is likely more useful for patients with recurrent tumors after conventional therapies, as well as for patients with diffuse non-muscle invasive bladder carcinomas that are refractory to standard treatments before the commitment to radical extirpative surgery, particularly in patients at surgical high risk. The treatment of tumors with PDT includes three major parameters: presence of oxygen in tumor tissue, administration of a photosensitizer, and subsequent exposure to light. The PDT mechanism relies on the in situ generation of cytotoxic agents by the activation of a light-sensitive drug, resulting in cell death. In this review, we present past and current advances in the use of PDT with urinary bladder cancer and discuss the future roles for this type of therapy in the treatment of bladder cancer.

Real-time absorption and scattering characterization of slab-shaped turbid samples obtained by a combination of angular and spatially resolved measurements.

We present a fast and accurate method for real-time determination of the absorption coefficient, the scattering coefficient, and the anisotropy factor of thin turbid samples by using simple continuous-wave noncoherent light sources. The three optical properties are extracted from recordings of angularly resolved transmittance in addition to spatially resolved diffuse reflectance and transmittance. The applied multivariate calibration and prediction techniques are based on multiple polynomial regression in combination with a Newton--Raphson algorithm. The numerical test results based on Monte Carlo simulations showed mean prediction errors of approximately 0.5% for all three optical properties within ranges typical for biological media. Preliminary experimental results are also presented yielding errors of approximately 5%. Thus the presented methods show a substantial potential for simultaneous absorption and scattering characterization of turbid media.