Targeting steroid hormone receptors for ubiquitination and degradation in breast and prostate cancer

Proteolysis targeting chimeric molecules (Protacs) target proteins for destruction by exploiting the ubiquitin-dependent proteolytic system of eukaryotic cells. We designed two Protacs that contain the peptide 'degron' from hypoxia-inducible factor-1alpha, which binds to the Von-Hippel-Lindau (VHL) E3 ubiquitin ligase complex, linked to either dihydroxytestosterone that targets the androgen receptor (AR; Protac-A), or linked to estradiol (E2) that targets the estrogen receptor-alpha (ERalpha; Protac-B). We hypothesized that these Protacs would recruit hormone receptors to the VHL E3 ligase complex, resulting in the degradation of receptors, and decreased proliferation of hormone-dependent cell lines. Treatment of estrogen-dependent breast cancer cells with Protac-B induced the degradation of ERalpha in a proteasome-dependent manner. Protac-B inhibited the proliferation of ERalpha-dependent breast cancer cells by inducing G(1) arrest, inhibition of retinoblastoma phosphorylation and decreasing expression of cyclin D1, progesterone receptors A and B. Protac-B treatment did not affect the proliferation of estrogen-independent breast cancer cells that lacked ERalpha expression. Similarly, Protac-A treatment of androgen-dependent prostate cancer cells induced G(1) arrest but did not affect cells that do not express AR. Our results suggest that Protacs specifically inhibit the proliferation of hormone-dependent breast and prostate cancer cells through degradation of the ERalpha and AR, respectively.

Phase I study of proteasome inhibitor bortezomib plus CHOP in patients with advanced, aggressive T-cell or NK/T-cell lymphoma

The aim of the study was to determine the maximum tolerated dose (MTD) and safety of the combination of bortezomib and cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) as first-line therapy in advanced, aggressive T-cell lymphoma. Patients received increasing doses of bortezomib on days 1 and 8 (weekly schedule, 1.0, 1.3, and 1.6 mg/m(2)/dose) in addition to 750 mg/m(2) cyclophosphamide, 50 mg/m(2) doxorubicin, 1.4 mg/m(2) vincristine on day 1 and 100 mg/day prednisolone on days 1 to 5, every 3 weeks. Six cycles of therapy administered every 21 days were planned. Thirteen patients, who had stage III/IV chemonaive aggressive T-cell lymphoma, received a total of 55 cycles of treatment. One patient experienced hematologic dose-limiting toxicity (grade 4 neutropenia associated with febrile episode) at the 1.0 mg/m(2)/dose of bortezomib. There was no dose-limiting non-hematologic toxicity. The MTD was not reached at 1.6 mg/m(2) dose level of bortezomib. The overall complete remission rate in all patients was 61.5% (95% confidence interval = 31.6-86.1). Bortezomib can be safely combined with CHOP chemotherapy and constitutes an active regimen in advanced-stage, aggressive T-cell lymphoma patients. The recommended dose for subsequent phase II studies of bortezomib plus CHOP is 1.6 mg/m(2)/dose of bortezomib on days 1 and 8 every 3 weeks as first-line treatment.

Simulating (electro)hydrodynamic effects in colloidal dispersions: smoothed profile method

Previously, we have proposed a direct simulation scheme for colloidal dispersions in a Newtonian solvent (Phys. Rev. E 71, 036707 (2005)). An improved formulation called the "Smoothed Profile (SP) method" is presented here in which simultaneous time-marching is used for the host fluid and colloids. The SP method is a direct numerical simulation of particulate flows and provides a coupling scheme between the continuum fluid dynamics and rigid-body dynamics through utilization of a smoothed profile for the colloidal particles. Moreover, the improved formulation includes an extension to incorporate multicomponent fluids, allowing systems such as charged colloids in electrolyte solutions to be studied. The dynamics of the colloidal dispersions are solved with the same computational cost as required for solving non-particulate flows. Numerical results which assess the hydrodynamic interactions of colloidal dispersions are presented to validate the SP method. The SP method is not restricted to particular constitutive models of the host fluids and can hence be applied to colloidal dispersions in complex fluids.

Safety and usefulness of bronchoscopy in ventilator-dependent patients with severe thrombocytopenia

Flexible bronchoscopy is a useful diagnostic procedure in patients with respiratory failure due to unexplained pulmonary infiltrates, but its safety and usefulness in ventilator-dependent patients with severe thrombocytopenia have not been established. A retrospective review of the medical records of all patients who underwent bronchoscopy while receiving mechanical ventilation support at Samsung Medical Centre, Seoul, Korea between January 2002 and July 2006 was conducted. The medical records of 37 patients with severe thrombocytopenia (platelet count <50,000 /microl) at the time of bronchoscopy were analysed. Mean platelet count was 27,300+/-12,500 /microl. The most common underlying condition was haematologic malignancy, which occurred in 21(56.7%) patients, followed by severe sepsis in five (13.6%) and post-liver transplantation complications and autoimmune disease in four each (10.8%). The procedures performed were bronchoalveolar lavage in 33 patients, washing in three and transbronchial lung biopsy in five. Two patients died within 24 hours of completing the procedure. In patients surviving longer than 24 hours, there was no significant decline in oxygenation index (PaO2/FiO2), sequential organ failure assessment score or simplified acute physiological score II after the procedure. Lung compliance significantly decreased at two hours post-bronchoscopy but recovered to the pre-bronchoscopy level by 24 hours. Intensive care unit mortality was 51.4% (19 of 37 patients). Bronchoscopy was helpful in confirming the diagnosis in 17 patients (45.9%). Therapeutic modifications were made in 14 patients (37.8%) after bronchoscopy. Severe thrombocytopenia per se should not preclude bronchoscopy, even in patients receiving mechanical ventilation.