Salinomycin inhibits prostate cancer growth and migration via induction of oxidative stress.

BACKGROUND: We have shown that a sodium ionophore monensin inhibits prostate cancer cell growth. A structurally related compound to monensin, salinomycin, was recently identified as a putative cancer stem cell inhibitor. METHODS: The growth inhibitory potential of salinomycin was studied in a panel of prostate cells. To get insights into the mechanism of action, a variety of assays such as gene expression and steroid profiling were performed in salinomycin-exposed prostate cancer cells. RESULTS: Salinomycin inhibited the growth of prostate cancer cells, but did not affect non-malignant prostate epithelial cells. Salinomycin impacted on prostate cancer stem cell functions as evidenced by reduced aldehyde dehydrogenase activity and the fraction of CD44(+) cells. Moreover, salinomycin reduced the expression of MYC, AR and ERG, induced oxidative stress as well as inhibited nuclear factor-κB activity and cell migration. Furthermore, profiling steroid metabolites revealed increased levels of oxidative stress-inducing steroids 7-ketocholesterol and aldosterone and decreased levels of antioxidative steroids progesterone and pregnenolone in salinomycin-exposed prostate cancer cells. CONCLUSION: Our results indicate that salinomycin inhibits prostate cancer cell growth and migration by reducing the expression of key prostate cancer oncogenes, inducing oxidative stress, decreasing the antioxidative capacity and cancer stem cell fraction.

Single-cell ATAC and RNA sequencing reveal pre-existing and persistent cells associated with prostate cancer relapse.

Prostate cancer is heterogeneous and patients would benefit from methods that stratify those who are likely to respond to systemic therapy. Here, we employ single-cell assays for transposase-accessible chromatin (ATAC) and RNA sequencing in models of early treatment response and resistance to enzalutamide. In doing so, we identify pre-existing and treatment-persistent cell subpopulations that possess regenerative potential when subjected to treatment. We find distinct chromatin landscapes associated with enzalutamide treatment and resistance that are linked to alternative transcriptional programs. Transcriptional profiles characteristic of persistent cells are able to stratify the treatment response of patients. Ultimately, we show that defining changes in chromatin and gene expression in single-cell populations from pre-clinical models can reveal as yet unrecognized molecular predictors of treatment response. This suggests that the application of single-cell methods with high analytical resolution in pre-clinical models may powerfully inform clinical decision-making.

Targeting Lyn regulates Snail family shuttling and inhibits metastasis.

The acquisition of an invasive phenotype by epithelial cells occurs through a loss of cellular adhesion and polarity, heralding a multistep process that leads to metastatic dissemination. Since its characterization in 1995, epithelial-mesenchymal transition (EMT) has been closely linked to the metastatic process. As a defining aspect of EMT, loss of cell adhesion through downregulation of E-cadherin is carried out by several transcriptional repressors; key among them the SNAI family of transcription factors. Here we identify for the first time that Lyn kinase functions as a key modulator of SNAI family protein localization and stability through control of the Vav-Rac1-PAK1 (Vav-Rac1-p21-activated kinase) pathway. Accordingly, targeting Lyn in vitro reduces EMT and in vivo reduces metastasis of primary tumors. We also demonstrate the clinical relevance of targeting Lyn as a key player controlling EMT; patient samples across many cancers revealed a strong negative correlation between Lyn and E-cadherin, and high Lyn expression in metastatic tumors as well as metastasis-prone primary tumors. This work reveals a novel pancancer mechanism of Lyn-dependent control of EMT and further underscores the role of this kinase in tumor progression.

A multicentre comparison of once-daily subcutaneous dalteparin (low molecular weight heparin) and continuous intravenous heparin in the treatment of deep vein thrombosis.

OBJECTIVES: To compare the efficacy and safety of the low molecular weight heparin (LMWH) dalteparin with unfractionated heparin (UFH) in the acute treatment of DVT patients who had not previously received UFH. DESIGN: An open randomized multicentre trial with blinded analysis of venograms. SETTING: Seven hospitals in Sweden, Finland and the USA. SUBJECTS: A total of 330 patients, of 20 years or older, with suspected DVT, verified using venography. INTERVENTIONS: Fixed-dose dalteparin (200 IU kg-1) given as a once-daily subcutaneous injection, or aPTT adjusted i.v. UFH infusion for 6 to 10 days. MAIN OUTCOME MEASURES: Change in Marder score in patients with confirmed DVT and two evaluable venograms; PE, bleeding events and follow-up. RESULTS: Marder scores improved in 51% (95% CI 42-60%) of 92 patients treated with dalteparin and in 62% (95% CI 53-70%) of 98 patients treated with UFH (P = 0.152). One dalteparin-treated patient had a PE confirmed by V/Q scan; another had progressive thrombosis with swelling in the affected limb. Bleeding complications occurred in six patients in each group. One patient treated with dalteparin and five treated with UFH died during the 6-month follow-up period as a result of underlying malignancy or heart disease. The 6-month recurrence rate was low with both treatments (dalteparin, 3/97; UFH, 2/103). CONCLUSIONS: Fixed-dose subcutaneous dalteparin given once daily from the start of treatment is of equivalent efficacy and safety to conventional UFH therapy in the routine management of DVT.