Development of taxane resistance in a panel of human lung cancer cell lines

Using a selection process designed to reflect clinically relevant conditions, a panel of taxane-selected variants were developed to study further the mechanisms of resistance in lung cancer. Unlike continuous or pulse exposure to high concentrations of chemotherapeutic drugs which yield high resistance and often cross resistance, most variants developed here displayed low level resistance to the selecting drug with slight cross-resistance. Pulsing with taxol resulted in more highly resistant clones (up to 51.4-fold). Analysis of taxol and taxotere in the four major lung cancer cell types showed the taxanes to be more effective against NSCLC (with the exception of SKMES-taxane selected variants) than against the SCLC. Comparison of taxol and taxotere shows that taxol induces higher levels of resistance than taxotere. Further, in taxotere-selected cell lines, the cells are more resistant to taxol than taxotere, suggesting that taxotere may be a superior taxane from a clinical view. Taxol treatment resulted in increased cross-resistance to 5-FU in all classes of lung cancer except DMS-53. The high levels of Pgp in the DMS-53 and selected variant suggests this mechanism is not related to Pgp expression. Analysis of the Pgp and MRP-1 status by combination inhibitory assays and Western blotting showed no consistent relationship between expression of the membrane pumps Pgp or MRP-1 and resistance. However, where high level resistance was seen, the parent cell line expressed Pgp or MRP-1 and was accompanied by increased levels in the variants. Overall we found that the clinically relevant models used here are useful for investigating mechanisms of taxane resistance

Ergogenic and psychological effects of synchronous music during circuit-type exercise

This is the post print version of the article. The official published version can be obtained from the link below.Objectives: Motivational music when synchronized with movement has been found to improve performance in anaerobic and aerobic endurance tasks, although gender differences pertaining to the potential benefits of such music have seldom been investigated. The present study addresses the psychological and ergogenic effects of synchronous music during circuit-type exercise. Design: A mixed-model design was employed in which there was a within-subjects factor (two experimental conditions and a control) and a between-subjects factor (gender). Methods: Participants (N ¼ 26) performed six circuit-type exercises under each of three synchronous conditions: motivational music, motivationally-neutral (oudeterous) music, and a metronome control. Dependent measures comprised anaerobic endurance, which was assessed using the number of repetitions performed prior to the failure to maintain synchronicity, and post-task affect, which was assessed using Hardy and Rejeski’s (1989) Feeling Scale. Mixed-model 3 (Condition) X 2 (Gender) ANOVAs, ANCOVAs, and MANOVA were used to analyze the data. Results: Synchronous music did not elicit significant (p < .05) ergogenic or psychological effects in isolation; rather, significant (p < .05) Condition X Gender interaction effects emerged for both total repetitions and mean affect scores. Women and men showed differential affective responses to synchronous music and men responded more positively than women to metronomic regulation of their movements. Women derived the greatest overall benefit from both music conditions. Conclusions: Men may place greater emphasis on the metronomic regulation of movement than the remaining, extra-rhythmical, musical qualities. Men and women appear to exhibit differential responses in terms of affective responses to synchronous music

In vitro development of chemotherapy and targeted therapy drug-resistant cancer cell lines: a practical guide with case studies

The development of a drug-resistant cell line can take from 3 to 18 months. However, little is published on the methodology of this development process. This article will discuss key decisions to be made prior to starting resistant cell line development; the choice of parent cell line, dose of selecting agent, treatment interval, and optimizing the dose of drug for the parent cell line. Clinically relevant drug-resistant cell lines are developed by mimicking the conditions cancer patients experience during chemotherapy and cell lines display between two- and eight-fold resistance compared to their parental cell line. Doses of drug administered are low, and a pulsed treatment strategy is often used where the cells recover in drug-free media. High-level laboratory models are developed with the aim of understanding potential mechanisms of resistance to chemotherapy agents. Doses of drug are higher and escalated over time. It is common to have difficulty developing stable clinically relevant drug-resistant cell lines. A comparative selection strategy of multiple cell lines or multiple chemotherapeutic agents mitigates this risk and gives insight into which agents or type of cell line develops resistance easily. Successful selection strategies from our research are presented. Pulsed-selection produced platinum or taxane-resistant large cell lung cancer (H1299 and H460) and temozolomide-resistant melanoma (Malme-3M and HT144) cell lines. Continuous selection produced a lapatinib-resistant breast cancer cell line (HCC1954). Techniques for maintaining drug-resistant cell lines are outlined including; maintaining cells with chemotherapy, pulse treating with chemotherapy, or returning to master drug-resistant stocks. The heterogeneity of drug-resistant models produced from the same parent cell line with the same chemotherapy agent is explored with reference to P-glycoprotein. Heterogeneity in drug-resistant cell lines reflects the heterogeneity that can occur in clinical drug resistance

Aldehyde dehydrogenase 1A1 and gelsolin identified as novel invasion-modulating factors in conditioned medium of pancreatic cancer cells

Conditioned medium (CM) from clonal sub-populations of the pancreatic cancer cell line, MiaPaCa-2 with differing invasive abilities, were examined for their effect on in vitro invasion. Conditioned medium from Clone #3 (CM#3) strongly promoted invasion, while CM from Clone #8 (CM#8) inhibited invasion in vitro. 2D DIGE followed by MALDI-TOF MS analysis of CM#3 and CM#8 identified 41 proteins which were differentially regulated; 27 proteins were down-regulated and 14 proteins up-regulated in the invasion-promoting CM#3 when compared to CM#8. Western blotting analysis confirmed the down-regulated expression of gelsolin and the up-regulation of aldehyde dehydrogenase 1A1 in CM#3. Down-regulation of aldehyde dehydrogenase 1A1 in Clone #3 CM and gelsolin levels in Clone #8 CM by siRNA transfection revealed an important involvement of these proteins in promoting and inhibiting invasion in these pancreatic cancer cell lines

Identification of proteins found to be significantly altered when comparing the serum proteome from Multiple Myeloma patients with varying degrees of bone disease

Background: Bone destruction is a feature of multiple myeloma, characterised by osteolytic bone destruction due to increased osteoclast activity and suppressed or absent osteoblast activity. Almost all multiple myeloma patients develop osteolytic bone lesions associated with severe and debilitating bone pain, pathologic fractures, hypercalcemia, and spinal cord compression, as well as increased mortality. Biomarkers of bone remodelling are used to identify disease characteristics that can help select the optimal management of patients. However, more accurate biomarkers are needed to effectively mirror the dynamics of bone disease activity. Results: A label-free mass spectrometry-based strategy was employed for discovery phase analysis of fractionated patient serum samples associated with no or high bone disease. A number of proteins were identified which were statistically significantly correlated with bone disease, including enzymes, extracellular matrix glycoproteins, and components of the complement system. Conclusions: Enzyme-linked immunosorbent assay of complement C4 and serum paraoxonase/arylesterase 1 indicated that these proteins were associated with high bone disease in a larger independent cohort of patient samples. These biomolecules may therefore be clinically useful in assessing the extent of bone disease. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-904) contains supplementary material, which is available to authorized users

Molecular pathogenesis and targeted therapy of sporadic pancreatic neuroendocrine tumors

Over the past few years, knowledge regarding the molecular pathology of sporadic pancreatic neuroendocrine tumors (PNETs) has increased substantially, and a number of targeted agents have been tested in clinical trials in this tumor type. For some of these agents there is a strong biological rationale. Among them, the mammalian target of rapamycin inhibitor Everolimus and the antiangiogenic agent Sunitinib have both been approved for the treatment of PNETs. However, there is lack of knowledge regarding biomarkers able to predict their efficacy, and mechanisms of resistance. Other angiogenesis inhibitors, such as Pazopanib, inhibitors of Src, Hedgehog or of PI3K might all be useful in association or sequence with approved agents. On the other hand, the clinical significance, and potential for treatment of the most common mutations occurring in sporadic PNETs, in the MEN-1 gene and in ATRX and DAXX, remains uncertain. The present paper reviews the main molecular changes occurring in PNETs and how they might be linked with treatment options

Environmental Regulation Can Arise Under Minimal Assumptions

Models that demonstrate environmental regulation as a consequence of organism and environment coupling all require a number of core assumptions. Many previous models, such as Daisyworld, require that certain environment-altering traits have a selective advantage when those traits also contribute towards global regulation. We present a model that results in the regulation of a global environmental resource through niche construction without employing this and other common assumptions. There is no predetermined environmental optimum towards which regulation should proceed assumed or coded into the model. Nevertheless, polymorphic stable states that resist perturbation emerge from the simulated co-evolution of organisms and environment. In any single simulation a series of different stable states are realised, punctuated by rapid transitions. Regulation is achieved through two main subpopulations that are adapted to slightly different resource values, which force the environmental resource in opposing directions. This maintains the resource within a comparatively narrow band over a wide range of external perturbations. Population driven oscillations in the resource appear to be instrumental in protecting the regulation against mutations that would otherwise destroy it. Sensitivity analysis shows that the regulation is robust to mutation and to a wide range of parameter settings. Given the minimal assumptions employed, the results could reveal a mechanism capable of environmental regulation through the by-products of organisms

Challenges of drug resistance in the management of pancreatic cancer

The current treatment of choice for metastatic pancreatic cancer involves single agent gemcitabine or combination of gemcitabine with capecitabine and erlotinib (tyrosine kinase inhibitor). Only 25-30% of patients respond to this treatment and patients who do respond initially ultimately exhibit disease progression. Median survival for pancreatic cancer patients has reached a plateau due to inherent and acquired resistance to these agents. Key molecular factors implicated in this resistance include: deficiencies in drug uptake, alteration of drug targets, activations of DNA repair pathways, resistance to apoptosis, and the contribution of the tumor microenvironment. Moreover, for newer agents including tyrosine kinase inhibitors, over expression of signaling proteins, mutations in kinase domains, activation of alternative pathways, mutations of genes downstream of the target, and/or amplification of the target represent key challenges for treatment efficacy. Here we will review the contribution of known mechanisms and markers of resistance to key pancreatic cancer drug treatments

HER2 testing in breast cancer: Opportunities and challenges

Human epidermal growth factor receptor 2 (HER2) is overexpressed in 15-25% of breast cancers, usually as a result of HER2 gene amplification. Positive HER2 status is considered to be an adverse prognostic factor. Recognition of the role of HER2 in breast cancer growth has led to the development of anti-HER2 directed therapy, with the humanized monoclonal antibody trastuzumab (Herceptin (R)) having been approved for the therapy of HER2-positive metastatic breast cancer. Clinical studies have further suggested that HER2 status can provide important information regarding success or failure of certain hormonal therapies or chemotherapies. As a result of these developments, there has been increasing demand to perform HER2 testing on current and archived breast cancer specimens. This article reviews the molecular background of HER2 function, activation and inhibition as well as current opinions concerning its role in chemosensitivity and interaction with estrogen receptor biology. The different tissue-based assays used to detect HER2 amplification and overexpression are discussed with respect to their advantages and disadvantages, when to test (at initial diagnosis or pre-treatment), where to test (locally or centralized) and the need for quality assurance to ensure accurate and valid testing results

Daisyworld: a review

Daisyworld is a simple planetary model designed to show the long-term effects of coupling between life and its environment. Its original form was introduced by James Lovelock as a defense against criticism that his Gaia theory of the Earth as a self-regulating homeostatic system requires teleological control rather than being an emergent property. The central premise, that living organisms can have major effects on the climate system, is no longer controversial. The Daisyworld model has attracted considerable interest from the scientific community and has now established itself as a model independent of, but still related to, the Gaia theory. Used widely as both a teaching tool and as a basis for more complex studies of feedback systems, it has also become an important paradigm for the understanding of the role of biotic components when modeling the Earth system. This paper collects the accumulated knowledge from the study of Daisyworld and provides the reader with a concise account of its important properties. We emphasize the increasing amount of exact analytic work on Daisyworld and are able to bring together and summarize these results from different systems for the first time. We conclude by suggesting what a more general model of life-environment interaction should be based on