Prevalence and causes of preoperative anaemia in elective major surgery patients.

BACKGROUND: Preoperative anaemia is associated with increased morbidity and mortality in surgical patients. Recent national patient blood management guideline recommended screening surgical patients for anaemia, particularly iron deficiency anaemia, without reference to the prevalence of anaemia or iron deficiency anaemia in this patient population. AIMS: To establish the prevalence and cause of preoperative anaemia in elective major surgery patients. METHODS: Patients attending the anaesthetic pre-admission clinics from 1 July 2013 to 30 June 2014 prior to their major elective surgery in our institution were screened for anaemia and iron deficiency by measuring full blood count, iron studies and C-reactive protein. Patients who were anaemic were either further assessed in the haematology clinic or had their medical records reviewed to ascertain the cause of the anaemia. RESULTS: Of 1494 patients, 208 (13.9%) were anaemic, with a male predominance (70.7%); 57 (27.4%) of them had iron deficiency anaemia. Other common causes of anaemia include underlying malignancy (18.3%), end-stage renal failure (11.5%) and other chronic diseases (7.2%). In 53 patients (25.5%), the cause was unknown. Anaemia was most commonly found in patients scheduled for gastrointestinal surgery. CONCLUSION: Preoperative anaemia affects 13.9% of patients undergoing elective major surgery. The most common causes are iron deficiency and chronic diseases. The cause was unexplained in 25.5% of patients with anaemia. The prevalence of anaemia in different surgical specialties may have implications on the approach to screening, particularly in resource-limited areas.

Strigolactone analogues induce apoptosis through activation of p38 and the stress response pathway in cancer cell lines and in conditionally reprogrammed primary prostate cancer cells.

Strigolactones are a novel class of plant hormones produced in roots and regulate shoot and root development. We have previously shown that synthetic strigolactone analogues potently inhibit growth of breast cancer cells and breast cancer stem cells. Here we show that strigolactone analogues inhibit the growth and survival of an array of cancer-derived cell lines representing solid and non-solid cancer cells including: prostate, colon, lung, melanoma, osteosarcoma and leukemic cell lines, while normal cells were minimally affected. Treatment of cancer cells with strigolactone analogues was hallmarked by activation of the stress-related MAPKs: p38 and JNK and induction of stress-related genes; cell cycle arrest and apoptosis evident by increased percentages of cells in the sub-G1 fraction and Annexin V staining. In addition, we tested the response of patient-matched conditionally reprogrammed primary prostate normal and cancer cells. The tumor cells exhibited significantly higher sensitivity to the two most potent SL analogues with increased apoptosis confirmed by PARP1 cleavage compared to their normal counterpart cells. Thus, Strigolactone analogues are promising candidates for anticancer therapy by their ability to specifically induce cell cycle arrest, cellular stress and apoptosis in tumor cells with minimal effects on growth and survival of normal cells.

PPARδ activation acts cooperatively with 3-phosphoinositide-dependent protein kinase-1 to enhance mammary tumorigenesis.

Peroxisome proliferator-activated receptorδ (PPARδ) is a transcription factor that is associated with metabolic gene regulation and inflammation. It has been implicated in tumor promotion and in the regulation of 3-phosphoinositide-dependent kinase-1 (PDK1). PDK1 is a key regulator of the AGC protein kinase family, which includes the proto-oncogene AKT/PKB implicated in several malignancies, including breast cancer. To assess the role of PDK1 in mammary tumorigenesis and its interaction with PPARδ, transgenic mice were generated in which PDK1 was expressed in mammary epithelium under the control of the MMTV enhancer/promoter region. Transgene expression increased pT308AKT and pS9GSK3ß, but did not alter phosphorylation of mTOR, 4EBP1, ribosomal protein S6 and PKCα. The transgenic mammary gland also expressed higher levels of PPARδ and a gene expression profile resembling wild-type mice maintained on a diet containing the PPARδ agonist, GW501516. Both wild-type and transgenic mice treated with GW501516 exhibited accelerated rates of tumor formation that were more pronounced in transgenic animals. GW501516 treatment was accompanied by a distinct metabolic gene expression and metabolomic signature that was not present in untreated animals. GW501516-treated transgenic mice expressed higher levels of fatty acid and phospholipid metabolites than treated wild-type mice, suggesting the involvement of PDK1 in enhancing PPARδ-driven energy metabolism. These results reveal that PPARδ activation elicits a distinct metabolic and metabolomic profile in tumors that is in part related to PDK1 and AKT signaling.

Induction of metastatic gastric cancer by peroxisome proliferator-activated receptorδ activation.

Peroxisome proliferator-activated receptorδ (PPARδ) regulates a multiplicity of physiological processes associated with glucose and lipid metabolism, inflammation, and proliferation. One or more of these processes likely create risk factors associated with the ability of PPARδ agonists to promote tumorigenesis in some organs. In the present study, we describe a new gastric tumor mouse model that is dependent on the potent and highly selective PPARδ agonist GW501516 following carcinogen administration. The progression of gastric tumorigenesis was rapid as determined by magnetic resonance imaging and resulted in highly metastatic squamous cell carcinomas of the forestomach within two months. Tumorigenesis was associated with gene expression signatures indicative of cell adhesion, invasion, inflammation, and metabolism. Increased PPARδ expression in tumors correlated with increased PDK1, Akt, ß-catenin, and S100A9 expression. The rapid development of metastatic gastric tumors in this model will be useful for evaluating preventive and therapeutic interventions in this disease.

Evaluation of pulsed high intensity focused ultrasound exposures on metastasis in a murine model.

High intensity focused ultrasound (HIFU) may be employed in two ways: continuous exposures for thermal ablation of tissue (> 60 degrees C), and pulsed-exposures for non-ablative effects, including low temperature hyperthermia (37-45 degrees C), and non thermal effects (e.g. acoustic cavitation and radiation forces). Pulsed-HIFU effects may enhance the tissue's permeability for improved delivery of drugs and genes, for example, by opening up gaps between cells in the vasculature and parenchyma. Inducing these effects may improve local targeting of therapeutic agents, however; concerns exist that pulsed exposures could theoretically also facilitate dissemination of tumor cells and exacerbate metastases. In the present study, the influence of pulsed-HIFU exposures on increasing metastatic burden was evaluated in a murine model with metastatic breast cancer. A preliminary study was carried out to validate the model and determine optimal timing for treatment and growth of lung metastases. Next, the effect of pulsed-HIFU on the metastatic burden was evaluated using quantitative image processing of whole-lung histological sections. Compared to untreated controls (2/15), a greater number of mice treated with pulsed-HIFU were found to have lungs "overgrown" with metastases (7/15), where individual metastases grew together such that they could not accurately be counted. Furthermore, area fraction of lung metastases (area of metastases/area of lungs) was approximately 30% greater in mice treated with pulsed-HIFU; however, these differences were not statistically significant. The present study details the development of an animal model for investigating the influence of interventional techniques or exposures (such as pulsed HIFU) on metastatic burden.

Activation of the RalGEF/Ral pathway promotes prostate cancer metastasis to bone.

A hallmark of metastasis is organ specificity; however, little is known about the underlying signaling pathways responsible for the colonization and growth of tumor cells in target organs. Since tyrosine kinase receptor activation is frequently associated with prostate cancer progression, we have investigated the role of a common signaling intermediary, activated Ras, in prostate cancer metastasis. Three effector pathways downstream of Ras, Raf/extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase, and Ral guanine nucleotide exchange factors (RalGEFs), were assayed for their ability to promote the metastasis of a tumorigenic, nonmetastatic human prostate cancer cell line, DU145. Oncogenic Ras promoted the metastasis of DU145 to multiple organs, including bone and brain. Activation of the Raf/ERK pathway stimulated metastatic colonization of the brain, while activation of the RalGEF pathway led to bone metastases, the most common organ site for prostate cancer metastasis. In addition, loss of RalA in the metastatic PC3 cell line inhibited bone metastasis but did not affect subcutaneous tumor growth. Loss of Ral appeared to suppress expansive growth of prostate cancer cells in bone, whereas homing and initial colonization were less affected. These data extend our understanding of the functional roles of the Ral pathway and begin to identify signaling pathways relevant for organ-specific metastasis.

Oncogenic K-RAS is required to maintain changes in cytoskeletal organization, adhesion, and motility in colon cancer cells.

RAS oncogenes are thought to play a role at multiple stages of tumorigenesis. The role and mechanisms by which RAS oncogenes maintain the transformed state of human cancer cells are poorly understood. Here, we have studied the role of oncogenic K-RAS in maintaining cytoskeletal disruption, cell adhesion and motility in metastatic colon carcinoma cells. Targeted deletion of K-RAS(G13D) from HCT116 colon carcinoma cells restored their ability to assemble stress fibers and focal adhesions/complexes, accompanied by increased cell-matrix adhesion and reduced motility. We further show that oncogenic K-Ras induces high Rho activity, but uncouples Rho from stress fiber formation. This uncoupling required the maintenance of high levels of the activator protein-1 family member, Fra-1, via a mitogen-activated protein/extracellular signal-regulated kinase-dependent pathway. We also show that PI3-kinase signaling is required for the motility of HCT116 cells downstream of oncogenic K-Ras. Our findings suggest that mutated K-RAS oncogenes are essential for maintenance of the transformed and invasive phenotype of human colon cancer cells.

Mechanisms of cancer metastasis to the bone.

Some of the most common human cancers, including breast cancer, prostate cancer, and lung cancer, metastasize with avidity to bone. What is the basis for their preferential growth within the bone microenvironment? Bidirectional interactions between tumor cells and cells that make up bone result in a selective advantage for tumor growth and can lead to bone destruction or new bone matrix deposition. This review discusses our current understanding of the molecular components and mechanisms that are responsible for those interactions.

Cyclic AMP-dependent kinase regulates Raf-1 kinase mainly by phosphorylation of serine 259.

The Raf-1 kinase activates the ERK (extracellular-signal-regulated kinase) pathway. The cyclic AMP (cAMP)-dependent protein kinase (PKA) can inhibit Raf-1 by direct phosphorylation. We have mapped all cAMP-induced phosphorylation sites in Raf-1, showing that serines 43, 259, and 621 are phosphorylated by PKA in vitro and induced by cAMP in vivo. Serine 43 phosphorylation decreased the binding to Ras in serum-starved but not in mitogen-stimulated cells. However, the kinase activity of a RafS43A mutant was fully inhibited by PKA. Mutation of serine 259 increased the basal Raf-1 activity and rendered it largely resistant to inhibition by PKA. cAMP increased Raf-1 serine 259 phosphorylation in a PKA-dependent manner with kinetics that correlated with ERK deactivation. PKA also decreased Raf-1 serine 338 phosphorylation of Raf-1, previously shown to be required for Raf-1 activation. Serine 338 phosphorylation of a RafS259A mutant was unaffected by PKA. Using RafS259 mutants we also demonstrate that Raf-1 is the sole target for PKA inhibition of ERK and ERK-induced gene expression, and that Raf-1 inhibition is mediated mainly through serine 259 phosphorylation.