Measurement of CYP1A2 and CYP3A4 activity by a simplified Geneva cocktail approach in a cohort of free-living individuals: a pilot study

Introduction: The cytochrome P450 enzyme subfamilies, including CYP3A4 and CYP1A2, have a major role in metabolism of a range of drugs including several anti-cancer treatments. Many factors including environmental exposures, diet, diseaserelated systemic inflammation and certain genetic polymorphisms can impact the activity level of these enzymes. As a result, the net activity of each enzyme subfamily can vary widely between individuals and in the same individual over time. This variability has potential major implications for treatment efficacy and risk of drug toxicity, but currently no assays are available for routine use to guide clinical decision-making.Methods: To address this, a mass spectrometry-based method to measure activities of CYP3A4, CYP1A2 was adapted and tested in free-living participants. The assay results were compared with the predicted activity of each enzyme, based on a self-report tool capturing diet, medication, chronic disease state, and tobacco usage. In addition, a feasibility test was performed using a low-volume dried blood spots (DBS) on two different filter-paper supports, to determine if the same assay could be deployed without the need for repeated standard blood tests.Results: The results confirmed the methodology is safe and feasible to perform in free-living participants using midazolam and caffeine as test substrates for CYP3A4 and CYP1A2 respectively. Furthermore, though similar methods were previously shown to be compatible with the DBS format, the assay can also be performed successfully while incorporating glucuronidase treatment into the DBS approach. The measured CYP3A4 activity score varied 2.6-fold across participants and correlated with predicted activity score obtained with the self-report tool. The measured CYP1A2 activity varied 3.5-fold between participants but no correlation with predicted activity from the self-report tool was found.Discussion: The results confirm the wide variation in CYP activity between individuals and the important role of diet and other exposures in determining CYP3A4 activity. This methodology shows great potential and future cross-sectional and longitudinal studies using DBS are warranted to determine how best to use the assay results to guide drug treatments

Apical Transport of Influenza A Virus Ribonucleoprotein Requires Rab11-positive Recycling Endosome

Influenza A virus RNA genome exists as eight-segmented ribonucleoprotein complexes containing viral RNA polymerase and nucleoprotein (vRNPs). Packaging of vRNPs and virus budding take place at the apical plasma membrane (APM). However, little is known about the molecular mechanisms of apical transport of newly synthesized vRNP. Transfection of fluorescent-labeled antibody and subsequent live cell imaging revealed that punctate vRNP signals moved along microtubules rapidly but intermittently in both directions, suggestive of vesicle trafficking. Using a series of Rab family protein, we demonstrated that progeny vRNP localized to recycling endosome (RE) in an active/GTP-bound Rab11-dependent manner. The vRNP interacted with Rab11 through viral RNA polymerase. The localization of vRNP to RE and subsequent accumulation to the APM were impaired by overexpression of Rab binding domains (RBD) of Rab11 family interacting proteins (Rab11-FIPs). Similarly, no APM accumulation was observed by overexpression of class II Rab11-FIP mutants lacking RBD. These results suggest that the progeny vRNP makes use of Rab11-dependent RE machinery for APM trafficking

After the chemotherapy: potential mechanisms for chemotherapy-induced delayed skeletal muscle dysfunction in survivors of acute lymphoblastic leukaemia in childhood

There is evidence that survivors of childhood cancers, such as acute lymphoblastic leukaemia (ALL), have increased rates of longterm skeletal muscle dysfunction. This places them at higher risk of physical restriction and functional impairment as well as potentially contributing to observed increases in cardiovascular disease and insulin resistance in later life. The mechanisms underlying these changes in skeletal muscle are unknown but chemotherapy drugs used in treatment for ALL are strongly implicated. Normal skeletal muscle growth, development and function are dependent on correctly functioning muscle satellite cells, muscle motor neurons and muscle mitochondria. Each of these key components is potentially susceptible to damage by chemotherapy in childhood, particularly prolonged courses including repeated administration of combination chemotherapy. If this chemotherapy-induced damage is not fully reversible, impairment of satellite cells, muscle motor innervation and mitochondria could, either singly or together, lead to the emergence of delayed or persistent skeletal muscle dysfunction many years later. The known effects of individual drugs used in the treatment of ALL are outlined and the need for specific targeted studies to investigate the mechanisms underlying persistent muscle dysfunction in survivors of childhood cancers is highlighted

Editorial: Adverse effects of cancer chemotherapy: Anything new to improve tolerance and reduce sequelae?

The side-effects and long-term sequelae of anti-cancer chemotherapy remain a major source of concern for both patients and clinicians despite the improved efficacy and enhanced survival offered by modern treatments. Current drugs or other approaches to counteract chemotherapyinduced adverse effects are often incompletely effective, frequently do not address potential longerterm sequelae or may even induce other side-effects which only add to patient discomfort. New approaches to improve tolerance and reduce sequelae of cancer chemotherapy are urgently needed and the present Research Topic focuses on this issue and highlights several areas of progress.RTJ receives salary support from the Peter Brojde Lung Cancer Centre and the Backler Foundation, Jewish General Hospital Foundation.Peer Reviewe

Adverse Effects of Cancer Chemotherapy: Anything New to Improve Tolerance and Reduce Sequelae?

Advances in anti-cancer chemotherapy over recent years have led to improved efficacy in curing or controlling many cancers. Some chemotherapy-related side-effects are well recognized and include: nausea, vomiting, bone marrow suppression, peripheral neuropathy, cardiac and skeletal muscle dysfunction and renal impairment. However, it is becoming clearer that some chemotherapy-related adverse effects may persist even in long term cancer survivors. Problems such as cognitive, cardiovascular and gastrointestinal dysfunction, and neuropathy may lead to substantial long term morbidity. Despite improvements in treatments to counteract acute chemotherapy-induced adverse effects, they are often incompletely effective. Furthermore, counter-measures for some acute side-effects and many potential longer term sequelae of anti-cancer chemotherapy have not been developed. Thus, new insights into prevalence and mechanisms of cancer chemotherapy-related side effects are needed and new approaches to improving tolerance and reduce sequelae of cancer chemotherapy are urgently needed. The present Research Topic focuses on adverse effects and sequelae of chemotherapy and strategies to counteract them

The alveolar microenvironment of patients infected with human immunodeficiency virus does not modify alveolar macrophage interactions with Streptococcus pneumoniae.

We tested the hypothesis that HIV infection results in activation of alveolar macrophages and that this might be associated with impaired defense against pneumococcus. We compared alveolar macrophages and lymphocytes in 131 bronchoalveolar lavage samples from HIV-infected and healthy controls using inflammatory gene microarrays, flow cytometry, real-time PCR, and enzyme-linked immunosorbent assay (ELISA) to determine the pattern of macrophage activation associated with HIV infection and the effect of this activation on defense against pneumococcus. We used gamma interferon (IFN-γ) priming to mimic the cellular milieu in HIV-infected lungs. InnateDB and BioLayout 3D were used to analyze the interactions of the upregulated genes. Alveolar macrophages from HIV-infected adults showed increased gene expression and cytokine production in a classical pattern. Bronchoalveolar lavage from HIV-infected subjects showed excess CD8(+) lymphocytes with activated phenotype. Toll-like receptor 4 (TLR4) expression was increased in macrophages from HIV-infected subjects, but function was similar between the groups; lung lavage fluid did not inhibit TLR function in transfected HeLa cells. Alveolar macrophages from HIV-infected subjects showed normal binding and internalization of opsonized pneumococci, with or without IFN-γ priming. Alveolar macrophages from HIV-infected subjects showed classical activation compared to that of healthy controls, but this does not alter macrophage interactions with pneumococci