The rate-limiting step and nonhyperbolic kinetics in the oxidation of ferrocytochrome c catalyzed by cytochrome c oxidase

AbstractThe level of reduction of cytochrome a and cua during the oxidation of ferrocytochrome c has been determined in stopped-flow experiments. Both components are partially reduced but become progressively more oxidized as the reaction proceeds. When all cytochrome c has been oxidized, cua is also completely oxidized, whereas cytochrome a is still partially reduced. These results can be simulated on the basis of a model which requires that the intramolecular electron transfer from cytochrome a and cua to cytochrome a3-Cub is a two-electron process and, in addition, that the binding of oxidized cytochrome c to the electron-transfer site decreases the rate constants for intramolecular electron transfer from cytochrome a. The first requirement is related to the function of the oxidase as a proton pump. Product dissociation is not by itself rate-limiting, making it less likely that the source of the nonhyperbolic substrate kinetics is an effect on this step from electrostatic interaction with ferricytochrome c bound to a second site. It is pointed out that nonhyperbolic kinetics is, in fact, an intrinsic property of ion pumps

New pathways for sustainable terpene materials from wood

Polymers play an essential role in everyday life as materials in automotive, packaging and electronics to compounds in medicine. Nevertheless, the finite supply of fossil fuels and lacking biodegradability of most synthetic polymers leads to an increased need for the development of more sustainable materials from renewable sources. The use of renewable natural products from forestry, especially hemicellulose and terpenes,1 offers a highly versatile platform for green building blocks. By using Nature’s own biofunctionalizations, enzymes can be used as green catalysts for the valorization of abundant terpenes from pine wood extractives. Enzymatic biotransformations enable mild processes for “activating” inert molecular building blocks to afford renewable monomers. By combining in vitro synthetic biology and polymer chemistry, we have generated a new bio based polymer starting from, a naturally abundantterpene found in wood. Specifically, acrylation of the terpene Sobrerol, which can be achieved§ both enzymatically and by using traditional chemistry, constituted a suitable synthon for Atom Transfer Radical Polymerization (ATRP); a common and widely used, controlled polymerization technique. Furthermore, we demonstrate that sobrerol can be generated from other abundant monoterpenes using P450-based biocatalysis. Please click Additional Files below to see the full abstract

Elevated levels of MMP12 sourced from macrophages are associated with poor prognosis in urothelial bladder cancer

Biomarkers; Proteomics; Urothelial bladder cancerBiomarcadores; Proteómica; Cáncer de vejiga urotelialBiomarcadors; Proteòmica; Càncer de bufeta urotelialBackground Urothelial bladder cancer is most frequently diagnosed at the non-muscle-invasive stage (NMIBC). However, recurrences and interventions for intermediate and high-risk NMIBC patients impact the quality of life. Biomarkers for patient stratification could help to avoid unnecessary interventions whilst indicating aggressive measures when required. Methods In this study, immuno-oncology focused, multiplexed proximity extension assays were utilised to analyse plasma (n = 90) and urine (n = 40) samples from 90 newly-diagnosed and treatment-naïve bladder cancer patients. Public single-cell RNA-sequencing and microarray data from patient tumour tissues and murine OH-BBN-induced urothelial carcinomas were also explored to further corroborate the proteomic findings. Results Plasma from muscle-invasive, urothelial bladder cancer patients displayed higher levels of MMP7 (p = 0.028) and CCL23 (p = 0.03) compared to NMIBC patients, whereas urine displayed higher levels of CD27 (p = 0.044) and CD40 (p = 0.04) in the NMIBC group by two-sided Wilcoxon rank-sum tests. Random forest survival and multivariable regression analyses identified increased MMP12 plasma levels as an independent marker (p < 0.001) associated with shorter overall survival (HR = 1.8, p < 0.001, 95% CI:1.3–2.5); this finding was validated in an independent patient OLINK cohort, but could not be established using a transcriptomic microarray dataset. Single-cell transcriptomics analyses indicated tumour-infiltrating macrophages as a putative source of MMP12. Conclusions The measurable levels of tumour-localised, immune-cell-derived MMP12 in blood suggest MMP12 as an important biomarker that could complement histopathology-based risk stratification. As MMP12 stems from infiltrating immune cells rather than the tumor cells themselves, analyses performed on tissue biopsy material risk a biased selection of biomarkers produced by the tumour, while ignoring the surrounding microenvironment.Open access funding provided by Uppsala University. This work was supported by the Swedish Society for Medical Research (S15-0065) to S.M. and the Swedish Cancer Foundation (CAN 2017/199) to P-U. M. The funding bodies did not influence the research performed

Prognostic and predictive impact of stroma cells defned by PDGFRb expression in early breast cancer: results from the randomized SweBCG91RT trial

Purpose Predictive biomarkers are needed to aid the individualization of radiotherapy (RT) in breast cancer. Cancer-associated fibroblasts have been implicated in tumor radioresistance and can be identified by platelet-derived growth factor receptor-beta (PDGFRb). This study aims to analyze how PDGFRb expression affects RT benefit in a large randomized RT trial. Methods PDGFRb was assessed by immunohistochemistry on tissue microarrays from 989 tumors of the SweBCG91RT trial, which enrolled lymph node-negative, stage I/IIA breast cancer patients randomized to RT after breast-conserving surgery. Outcomes were analyzed at 10 years for ipsilateral breast tumor recurrence (IBTR) and any recurrence and 15 years for breast cancer specific death (BCSD). Results PDGFRb expression correlated with estrogen receptor negativity and younger age. An increased risk for any recurrence was noted in univariable analysis for the medium (HR 1.58, CI 95% 1.11–2.23, p = 0.011) or PDGFRb high group (1.49, 1.06–2.10, p = 0.021) compared to the low group. No differences in IBTR or BCSD risk were detected. RT benefit regarding IBTR risk was significant in the PDGFRb low (0.29, 0.12–0.67, p = 0.004) and medium (0.31, 0.16–0.59, p < 0.001) groups but not the PDGFRb high group (0.64, 0.36–1.11, p = 0.110) in multivariable analysis. Likewise, risk reduction for any recurrence was less pronounced in the PDGFRb high group. No significant interaction between RT and PDGFRb-score could be detected. Conclusion A higher PDGFRb-score conferred an increased risk of any recurrence, which partly can be explained by its association with estrogen receptor negativity and young age. Reduced RT benefit was noted among patients with high PDGFRb, however without significant interaction.publishedVersio

Claudin-2 is an independent negative prognostic factor in breast cancer and specifically predicts early liver recurrences.

Predicting any future metastatic site of early-stage breast cancer is important as it significantly influences the prognosis of advanced disease. This study aimed at investigating the potential of claudin-2, over-expressed in breast cancer liver metastases, as a biomarker for predicting liver metastatic propensity in primary breast cancer

Histological grade provides significant prognostic information in addition to breast cancer subtypes defined according to St Gallen 2013

Background: The St Gallen surrogate definition of the intrinsic subtypes of breast cancer consist of five subgroups based on estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor type 2 (HER2), and Ki-67. PgR and Ki-67 are used for discriminating between the ‘Luminal A-like’ and ‘Luminal B-like (HER2-negative)’ subtypes. Histological grade (G) has prognostic value in breast cancer; however, its relationship to the St Gallen subtypes is not clear. Based on a previous pilot study, we hypothesized that G could be a primary discriminator for ER-positive/HER2-negative breast cancers that were G1 or G3, whereas Ki-67 and PgR could provide additional prognostic information specifically for patients with G2 tumors. To test this hypothesis, a larger patient cohort was examined. Patients and methods: Six hundred seventy-one patients (≥35 years of age, pT1-2, pN0-1) with ER-positive/HER2-negative breast cancer and complete data for PgR, Ki-67, G, lymph node status, tumor size, age, and distant disease-free survival (DDFS; median follow-up 9.2 years) were included. Results: ‘Luminal A-like’ tumors were mostly G1 or G2 (90%) whereas ‘Luminal B-like’ tumors were mostly G2 or G3 (87%) and corresponded with good and poor DDFS, respectively. In ‘Luminal B-like’ tumors that were G1 (n = 23), no metastasis occurred, whereas 14 of 40 ‘Luminal A-like’ tumors that were G3 metastasized. In the G2 subgroup, low PgR and high Ki-67 were associated with an increased risk of distant metastases, hazard ratio (HR) and 95% confidence interval (CI) 1.8 (0.95–3.4) and 1.5 (0.80–2.8), respectively. Conclusions: Patients with ER-positive/HER2-negative/G1 breast cancer have a good prognosis, similar to that of ‘Luminal A-like’, while those with ER-positive/HER2-negative/G3 breast cancer have a worse prognosis, similar to that of ‘Luminal B-like’, when assessed independently of PgR and Ki-67. Therapy decisions based on Ki-67 and PgR might thus be restricted to the subgroup G2

Progress towards a Nordic standard for the investigation of hematuria: 2019

Objective: To describe the management of patients with hematuria in the Nordic countries in relation to bladder cancer epidemiology, especially in the context of introducing fast track pathways with the aim of proposing a common guideline.Materials and methods: Epidemiological data on bladder cancer from each country, and the combined cancer registry, Nordcan, were analyzed. The evolution of the different national recommendations and the introduction of fast track pathways were assessed. Patients' demographics, type of hematuria and cancer detection rates were analysed if available.Results: The crude incidence of bladder cancer has increased substantially since the 1960s, while the age standardized incidence has been stable during recent decades. The relative survival has increased in all countries, while the mortality has been stable. For those with microscopic hematuria there has been a clear trend towards less rigorous investigations. In the fast track pathways, introduced in three of five countries, about one in five patients with macroscopic hematuria had a cancer diagnosis. Data show that time to diagnosis has been reduced.Conclusions: The number of patients with bladder cancer is increasing in the Nordic region. The introduction of fast track pathways has been important in improving the management of patients with suspicion of the disease. Our recommendation is to focus on macroscopic hematuria in the fast track pathways. Microhematuria without any symptoms should not be an indication for cystoscopy. However, urinary tract symptoms accompanied by microhematuria can still be investigated according to respective guidelines but not necessarily within fast track pathways.</p

Elevated levels of MMP12 sourced from macrophages are associated with poor prognosis in urothelial bladder cancer

Abstract Background Urothelial bladder cancer is most frequently diagnosed at the non-muscle-invasive stage (NMIBC). However, recurrences and interventions for intermediate and high-risk NMIBC patients impact the quality of life. Biomarkers for patient stratification could help to avoid unnecessary interventions whilst indicating aggressive measures when required. Methods In this study, immuno-oncology focused, multiplexed proximity extension assays were utilised to analyse plasma (n = 90) and urine (n = 40) samples from 90 newly-diagnosed and treatment-naïve bladder cancer patients. Public single-cell RNA-sequencing and microarray data from patient tumour tissues and murine OH-BBN-induced urothelial carcinomas were also explored to further corroborate the proteomic findings. Results Plasma from muscle-invasive, urothelial bladder cancer patients displayed higher levels of MMP7 (p = 0.028) and CCL23 (p = 0.03) compared to NMIBC patients, whereas urine displayed higher levels of CD27 (p = 0.044) and CD40 (p = 0.04) in the NMIBC group by two-sided Wilcoxon rank-sum tests. Random forest survival and multivariable regression analyses identified increased MMP12 plasma levels as an independent marker (p < 0.001) associated with shorter overall survival (HR = 1.8, p < 0.001, 95% CI:1.3–2.5); this finding was validated in an independent patient OLINK cohort, but could not be established using a transcriptomic microarray dataset. Single-cell transcriptomics analyses indicated tumour-infiltrating macrophages as a putative source of MMP12. Conclusions The measurable levels of tumour-localised, immune-cell-derived MMP12 in blood suggest MMP12 as an important biomarker that could complement histopathology-based risk stratification. As MMP12 stems from infiltrating immune cells rather than the tumor cells themselves, analyses performed on tissue biopsy material risk a biased selection of biomarkers produced by the tumour, while ignoring the surrounding microenvironment

Non-muscle-invasive bladder cancer: a vision for the future

The management of non-muscle-invasive bladder cancer (NMIBC) has evolved from the first reports on bladder endoscopy and transurethral resection to the introduction of adjuvant intravesical treatment. However, disease recurrence and progression remain an ongoing risk, placing a heavy burden on healthcare resources and on patients' quality of life. Deeper understanding of the molecular basis of the disease and developments in optics, lasers and computer science are already offering opportunities to revolutionize care and improve long-term prognosis. This article discusses developments likely to cause a paradigm shift towards the delivery of personalized care and reduced burden of disease in NMIBC