Tumour expression of leptin is associated with chemotherapy resistance and therapy-independent prognosis in gastro-oesophageal adenocarcinomas.

BACKGROUND: Cytotoxic chemotherapy remains the main systemic therapy for gastro-oesophageal adenocarcinoma, but resistance to chemotherapy is common, resulting in ineffective and often toxic treatment for patients. Predictive biomarkers for chemotherapy response would increase the probability of successful therapy, but none are currently recommended for clinical use. We used global gene expression profiling of tumour biopsies to identify novel predictive biomarkers for cytotoxic chemotherapy. METHODS: Tumour biopsies from patients (n=14) with TNM stage IB-IV gastro-oesophageal adenocarcinomas receiving platinum-based combination chemotherapy were used as a discovery cohort and profiled with Affymetrix ST1.0 Exon Genechips. An independent cohort of patients (n=154) treated with surgery with or without neoadjuvant platinum combination chemotherapy and gastric adenocarcinoma cell lines (n=22) were used for qualification of gene expression profiling results by immunohistochemistry. A cisplatin-resistant gastric cancer cell line, AGS Cis5, and the oesophageal adenocarcinoma cell line, OE33, were used for in vitro validation investigations. RESULTS: We identified 520 genes with differential expression (Mann-Whitney U, P<0.020) between radiological responding and nonresponding patients. Gene enrichment analysis (DAVID v6.7) was used on this list of 520 genes to identify pathways associated with response and identified the adipocytokine signalling pathway, with higher leptin mRNA associated with lack of radiological response (P=0.011). Similarly, in the independent cohort (n=154), higher leptin protein expression by immunohistochemistry in the tumour cells was associated with lack of histopathological response (P=0.007). Higher leptin protein expression by immunohistochemistry was also associated with improved survival in the absence of neoadjuvant chemotherapy, and patients with low leptin protein-expressing tumours had improved survival when treated by neoadjuvant chemotherapy (P for interaction=0.038). In the gastric adenocarcinoma cell lines, higher leptin protein expression was associated with resistance to cisplatin (P=0.008), but not to oxaliplatin (P=0.988) or 5fluorouracil (P=0.636). The leptin receptor antagonist SHLA increased the sensitivity of AGS Cis5 and OE33 cell lines to cisplatin. CONCLUSIONS: In gastro-oesophageal adenocarcinomas, tumour leptin expression is associated with chemoresistance but a better therapy-independent prognosis. Tumour leptin expression determined by immunohistochemistry has potential utility as a predictive marker of resistance to cytotoxic chemotherapy, and a prognostic marker independent of therapy in gastro-oesophageal adenocarcinoma. Leptin antagonists have been developed for clinical use and leptin and its associated pathways may also provide much needed novel therapeutic targets for gastro-oesophageal adenocarcinoma.

[F]fluoro-2-deoxy-d-glucose incorporation by mcf-7 breast tumour cells in vitro is modulated by treatment with tamoxifen, Doxorubicin, and docetaxel: relationship to chemotherapy-induced changes in ATP content, hexokinase activity, and glucose transport.

Breast tumours responding to chemotherapy exhibit decreased [(18)F]fluoro-2-deoxy-D-glucose ([(18)F]FDG) incorporation. Underlying mechanisms of these changes is poorly understood. Here, in MCF-7 cells, responding to chemotherapy drugs commonly utilised in the treatment of breast cancer, [(18)F]FDG incorporation and several pivotal factors associated with [(18)F]FDG incorporation investigated. Methods. IC50 and subclinical doxorubicin, docetaxel, and tamoxifen doses determined using MTT assay. [(18)F]FDG incorporation by cells treated with IC50 drug doses for 48 hours and 72 hours were determined and FDG dephosphorylation estimated by measuring loss of 18F from [(18)F]FDG-preincubated cells (pulse-chase). Glucose transport determined by measuring initial uptake rate of non-metabolised glucose analogue omethylglucose; hexokinase activity and ATP content measured in cell homogenates; Cell cycle distribution determined using flow cytometry of propidium iodide stained nuclei. Results. [(18)F]FDG incorporation and ATP content decreased in cells after 72 hours treatment with IC50 doses of tamoxifen, doxorubicin, and docetaxel compared with untreated controls. Decreased glucose transport and/or hexokinase activity accompanied decreased [(18)F]FDG incorporation by MCF-7 cells treated with tamoxifen or doxorubicin but not docetaxel. Conclusions. Tumour cell [(18)F]FDG incorporation along with ATP content decreased by treatment with tamoxifen, doxorubicin and docetaxel paralleling clinical observations for solid tumours. Effect of each treatment on glucose transport and hexokinase activity was chemotherapy-drug dependent.

Femoral head viability after Birmingham resurfacing hip arthroplasty: assessment with use of [18F] fluoride positron emission tomography.

BACKGROUND: Total hip resurfacing has become increasingly popular over the last decade. There remains concern about the effect of the surgical approach on femoral head viability and the role of resurfacing in the management of established osteonecrosis. In view of these concerns, we examined femoral head viability following resurfacing through a modified anterolateral approach. METHODS: The viability of the femoral heads of ten patients who had undergone successful unilateral Birmingham hip resurfacing was assessed with use of positron emission tomography in conjunction with the injection of fluorine at a mean of twenty months after surgery. For each patient, in both the hip that had undergone resurfacing and the contralateral nonresurfaced hip, activity was measured in four regions of interest: the lateral aspect of the femoral head, the medial aspect of the femoral head, the lateral aspect of the femoral neck, and the proximal aspect of the femur. The uptake of fluorine in each area was converted to standard uptake volumes. RESULTS: No areas of osteonecrosis were seen in the femoral head of any patient. There were no significant differences in the standard uptake volumes as measured in the four regions of the nonresurfaced hips, whereas the median values were higher in all four regions of the resurfaced hips. The difference between the values in the resurfaced hips compared with those in the nonresurfaced hips was only significant (p < 0.05) in the lateral aspect of the femoral head. CONCLUSIONS: This study establishes positron emission tomography in conjunction with injection of fluorine as a possible modality for the assessment of femoral head viability after hip resurfacing. Viability following successful Birmingham hip resurfacing performed through a modified anterolateral approach has also been demonstrated. The increase in bone activity that was seen in the resurfaced hips in our study group may be related to bone remodeling or reperfusion of small areas of osteonecrosis. This technique offers the potential to study femoral head perfusion and viability following all types of resurfacing. LEVEL OF EVIDENCE: Diagnostic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

[Evaluation of some thin-layer chromatography procedures for the identification and detection of impurities of hormonal steroids]. / Studio collaborativo per la valutazione di aleune metodiche di cromatografia in strato sottile per i'dentificazione ed il saggio di purezza di steroidi ad attività ormonale

PIP: The thin-layer chromatography methods described in Volume 2 of the "European Pharmacopeia" were tested to determine the most suitable methods for the identification of hormonal steroids and for the detection of impurities in these substances. The methods are based on partition chromatography for identification and on adsorption chromatogr aphy for the detection of impurities. Other adsorption methods developed by the authors were also tested. The study was conducted on 44 steroids, belonging to the groups of androgens, estrogens, progestinic and corticoid steroids. 9 chromatographic methods based on adsorption, 2 in bidimensional succession, and 7 methods based on partit ion were used. The work was carried out in 6 laboratories. The findings are summarized in 18 tables and illustrated in 13 figures. They were also processed by statistical methods in order to assess the reproducibility of the tests.^ieng