Pharmacodynamic and Clinical Results from a Phase I/II Study of the HSP90 Inhibitor Onalespib in Combination with Abiraterone Acetate in Prostate Cancer

PURPOSE

Onalespib is a potent, fragment-derived second-generation HSP90 inhibitor with preclinical activity in castration-resistant prostate cancer (CPRC) models. This phase I/II trial evaluated onalespib in combination with abiraterone acetate (AA) and either prednisone or prednisolone (P) in men with CRPC progressing on AA/P.

PATIENTS AND METHODS

Patients with progressing CRPC were randomly assigned to receive 1 of 2 regimens of onalespib combined with AA/P. Onalespib was administered as intravenous infusion starting at 220 mg/m2 once weekly for 3 of 4 weeks (regimen 1); or at 120 mg/m2 on day 1 and day 2 weekly for 3 of 4 weeks (regimen 2). Primary endpoints were response rate and safety. Secondary endpoints included evaluation of androgen receptor (AR) depletion in circulating tumor cells (CTC) and in fresh tumor tissue biopsies.

RESULTS

Forty-eight patients were treated with onalespib in combination with AA/P. The most common ≥grade 3 toxicities related to onalespib included diarrhea (21%) and fatigue (13%). Diarrhea was dose limiting at 260 and 160 mg/m2 for regimens 1 and 2, respectively. Transient decreases in CTC counts and AR expression in CTC were observed in both regimens. HSP72 was significantly upregulated following onalespib treatment, but only a modest decrease in AR and GR was shown in paired pre- and posttreatment tumor biopsy samples. No patients showed an objective or PSA response.

CONCLUSIONS

Onalespib in combination with AA/P showed mild evidence of some biological effect; however, this effect did not translate into clinical activity, hence further exploration of this combination was not justified.

Predictors of permanent pacemaker requirement after cardiac surgery for infective endocarditis

BACKGROUND

Infectious endocarditis is often complicated by conduction abnormalities at the time of presentation. Cardiac surgery is the treatment of choice for many infectious endocarditis patients, but carries an additional risk of persistent postoperative conduction abnormality. We sought to define the incidence and clinical predictors of significant postoperative conduction abnormalities necessitating permanent pacemaker implantation after cardiac surgery for infectious endocarditis.

METHODS

All consecutive patients with infectious endocarditis who were surgically treated at Cleveland Clinic from 2007 to 2013 were identified using the Cleveland Clinic Infective Endocarditis Registry and the Cardiovascular Information Registry. Patients with a pre-existing cardiac implantable electronic device were excluded. The primary outcome was the need for permanent pacemaker placement postoperatively for atrioventricular block. Regression analysis was performed to identify risk factors for permanent pacemaker requirement.

RESULTS

Among 444 infectious endocarditis patients who underwent cardiac surgery for infectious endocarditis, 57 (13%) required postoperative permanent pacemaker for atrioventricular block. Multivariable analysis identified that prolongation in preoperative PR and QRS intervals, Staphylococcus aureus as the infectious endocarditis organism, the presence of intracardiac abscess, tricuspid valve involvement, and prior valvular surgery independently predicted postoperative permanent pacemaker placement. The developed model exhibited excellent predictive ability (c-statistic 0.88) and calibration.

CONCLUSION

Infectious endocarditis cardiac surgery patients often require a postoperative permanent pacemaker. Preoperative conduction abnormality, S. aureus infection, abscess, tricuspid valve involvement, and prior valvular surgery are strong predictors of postoperative permanent pacemaker placement.

Maintenance of SOX9 stability and ECM homeostasis by selenium-sensitive PRMT5 in cartilage

OBJECTIVES

Selenium (Se) plays pivotal roles in maintaining optimal health. Nevertheless, how Se influences the metabolism of extracellular matrix (ECM) in cartilage remains unclear. The aim of the present study was to observe protein dimethylation by certain Se-sensitive PRMT and to elucidate its effects on the key transcriptional factor in cartilage.

METHODS

We observed the expression of selenoproteins and markers of ECM metabolism in chondrocytes and articular cartilage of the rats under Se-deficiency by RT-qPCR, immunoblotting and immunohistochemistry. Then, we analyzed the expression of total dimethylated protein by using specific antibody under different Se statuses. After Se sensitive PRMT was identified, we used siRNA or PRMT inhibitor or stably overexpressing vector to intervene in the PRMT expression and identified the key transcriptional factor. Co-immunoprecipitation was applied to verify the interaction between PRMT and the key transcriptional factor. Finally, we measured the half-life time of the key transcriptional factor by immunoblotting after cycloheximide treatment.

RESULTS

In chondrocytes and cartilage of the rats with Se deficiency, we found an aberrant metabolism manifesting decreased expression of Col2a1 and increased expression of Mmp-3. Then, we identified that PRMT5 was the unique type II PRMT, sensitive to Se status. PRMT5 upregulation led to the increased COL2A1 expression but decreased MMP-3 expression in chondrocytes. Furthermore, we revealed that PRMT5 improved SOX9 stability by dimethylating the protein, which contributed to maintain the matrix metabolic homeostasis of the chondrocytes.

CONCLUSIONS

Se-sensitive PRMT5 increases the half-life of SOX9 protein via PTM and helps to maintain ECM homeostasis of the articular cartilage.

Vinflunine in the treatment of relapsed metastatic urothelial cancer: A systematic review and meta-analysis of real-world series

BACKGROUND

Vinflunine (VFL) is approved in Europe as second-line treatment of metastatic urothelial cancer after failure of platinum-containing therapy. We performed a systematic review and meta-analysis of real-world data (RWD) to assess utilization, efficacy and safety of VFL.

METHODS

We performed a MEDLINE search for the period of 1/1/2000-31/8/2017. Full-length articles providing post-marketing RWD on VFL in patients failing previous chemotherapy were eligible. Interventional clinical trials were excluded.

RESULTS

Ten studies with 797 patients were identified. According to pooled REs analysis, overall response rate was 19%, most frequent, all-grade toxicities were fatigue (41%), constipation (39%), nausea/vomiting (25%), and most prevalent Grade 3-4 toxicities were neutropenia (13%), anaemia (9%), fatigue (8%). Median OS was comparable to results reported in recent randomized studies.

CONCLUSION

Our findings confirm the efficacy and safety of VFL in an unselected population and support the use of VFL in the changing treatment paradigm of relapsed mUC.

Degradation of azo dyes by Alcaligenes aquatilis 3c and its potential use in the wastewater treatment

In the present study, Alcaligenes aquatilis was found to decolorize 82% Synazol red 6HBN after incubation of 4 days at 37 °C and pH 7. Maximum decolorization was found under static conditions by using saw dust and yeast extract as carbon and nitrogen source. It also showed promising potential to decolorize mixture of multiple dyes at a rate of more than 86% in 5 days. Decolorization of dye had positive influence on the growth of bacterium as growth rate was increased along with decolorization. The cleavage of azo bond was confirmed through TLC, HPLC and GC–MS analysis. The dye metabolites produced during bacterial treatment are linked to various pathways including ATP synthesis process. The absence of peaks of wavelength 1612/cm and 1532/cm in bacterially treated FTIR sample demonstrated the cleavage of azo bond. Microbial growth in decolorized dye wastewater shows that bacterially decolorized wastewater is unharmful for the growth of micro-flora. The high decolorization ability of A. aquatilis 3c to convert toxic azo dyes into useful end products may find potential applications in the environmental biotechnology.

Antibodies raised against aldehyde-fixed antigens improve sensitivity for postembedding electron microscopy

BACKGROUND

Antibodies are one of the most important tools in biological research. High specificity and sensitivity of antibodies are crucial to obtain reliable results. Tissue fixed with glutaraldehyde (GA) is commonly used in electron microscopical investigations. The fixation and embedding routine in preparation of tissue for post-embedding electron microscopy (EM) will mask and structurally alter epitopes, making antibody-antigen interaction inefficient, with low labeling intensities. One of the main factors in this regard is the use of GA as fixative.

NEW METHOD

To alleviate these technical challenges, we immunized rabbits with antigen pre-fixed with GA. We hypothesized that the resulting antibodies would have stronger affinity to antigens that have been conformationally changed and denatured by GA, the way they are in fixed tissue.

COMPARISON WITH EXISTING METHOD AND RESULTS

An initial screening with western blotting (WB) showed results consistent with our hypothesis. In-house antibodies raised against GA-fixed SNARE proteins SNAP-25 and VAMP2, binds more strongly to fixed proteins compared to non-fixed proteins, while the pattern is opposite with the commercially available antibodies raised against non-fixed antigens (standard antibodies). Quantitative post-embedding EM of hippocampal synapses gave higher labeling intensities with anti-GA-SNAP-25 and anti-GA-VAMP2 compared to standard antibodies. Importantly, light microscopy (LM) and EM with our antibodies revealed stronger labeling of GA-fixed than formaldehyde (FH) treated brains.

CONCLUSION

Our results highlight the experimental potential of raising antibodies against GA-treated antigen to improve sensitivity of the antibodies for postembedding immunogold EM.