Characterization of mammary cancer stem cells in the MMTV-PyMT mouse model

Breast cancer stem cells, the root of tumor growth, present challenges to investigate: Primary human breast cancer cells are difficult to establish in culture and inconsistently yield tumors after transplantation into immune-deficient recipient mice. Furthermore, there is limited characterization of mammary cancer stem cells in mice, the ideal model for the study of breast cancer. We herein describe a pre-clinical breast cancer stem cell model, based on the properties of cancer stem cells, derived from transgenic MMTV-PyMT mice. Using a defined set of cell surface markers to identify cancer stem cells by flow cytometry, at least four cell populations were recovered from primary mammary cancers. Only two of the four populations, one epithelial and one mesenchymal, were able to survive and proliferate in vitro. The epithelial population exhibited tumor initiation potential with as few as 10 cells injected into syngeneic immune-competent recipients. Tumors initiated from injected cell lines recapitulated the morphological and physiological components of the primary tumor. To highlight the stemness potential of the putative cancer stem cells, B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) expression was knocked down via shRNA targeting Bmi-1. Without Bmi-1 expression, putative cancer stem cells could no longer initiate tumors, but tumor initiation was rescued with the introduction of a Bmi-1 overexpression vector in the Bmi-1 knockdown cells. In conclusion, our data show that primary mammary cancers from MMTV-PyMT mice contain putative cancer stem cells that survive in culture and can be used to create a model for study of mammary cancer stem cells.     

Direct and indirect contribution of bone marrow‐derived cells to cancer

Stromal‐epithelial interactions may control the growth and initiation of cancers. Here, we not only test the hypothesis that bone marrow‐derived cells may effect development of cancers arising from other tissue cells by forming tumor stroma but also that sarcomas may arise by transformation of stem cells from the bone marrow and epithelial cancers may arise by transdifferentiation of bone marrow stem cells to epithelial cancers. Lethally irradiated female FVB/N mice were restored with bone marrow (BM) transplants from a male transgenic mouse carrying the polyoma middle T‐oncoprotein under the control of the mouse mammary tumor virus promoter (MMTV‐PyMT) and followed for development of lesions. All of 8 lethally irradiated female FVB/N recipient mice, restored with BM transplants from a male MMTV‐PyMT transgenic mouse, developed Y‐chromosome negative (Y−) cancers of various organs surrounded by Y+ stroma. One of the female FVB/N recipient mice also developed fibrosarcoma and 1, a diploid breast adenocarcinoma containing Y chromosomes. In contrast, only 1 of 12 control female mice restored with normal male BM developed a tumor (lymphoma) during the same time period. These results indicate not only that the transgenic BM‐derived stromal cells may indirectly contribute to development of tumors in recipient mice but also that sarcomas may arise by transformation of BM stem cells and that breast cancers arise by transdifferentiation of BM stem cells, presumably by mesenchymal‐epithelial transition.     

The effect of direction and reaction on the neuromuscular and biomechanical characteristics of the knee during tasks that simulate the noncontact anterior cruciate ligament injury mechanism

BACKGROUND: Jumping and landing tasks that have a change in direction have been implicated as a mechanism of noncontact anterior cruciate ligament injury. Yet, to date, neuromuscular and biomechanical research has focused primarily on straight landing tasks during planned jumps. HYPOTHESIS: Lateral and reactive jumps increase the neuromuscular and biomechanical demands placed on the anterior cruciate ligament, and women perform these tasks differently from men. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 18 male and 17 female healthy high school basketball players underwent an analysis of the knee during planned and reactive 2-legged stop-jump tasks in 3 different directions that included novel methodology to incorporate a reactive component. Ground-reaction forces, joint kinematics, joint kinetics, and electromyographic activity were assessed during the tasks. RESULTS: Jump direction and task (planned or reactive) significantly affected joint angles, ground-reaction forces, knee joint moments, and proximal anterior tibia shear forces; female players demonstrated different kinematic, kinetic, and electromyographic characteristics during these tasks.Conclusion and CLINICAL RELEVANCE: Jump direction significantly influenced knee biomechanics, suggesting that lateral jumps are the most dangerous of the stop-jumps. Reactive jumps were also significantly different, suggesting differences between planned laboratory experiments and actual athletic competition. The results of this study indicate that directional and reactive jumps should be included in research methodology and injury-prevention programs.     

Biodistribution and radiation dosimetry in healthy volunteers of a novel tumour-specific probe for PET/CT imaging: BAY 85-8050

Purpose

Novel tracers for the diagnosis of malignant disease with PET and PET/CT are being developed as the most commonly used ¹⁸F deoxyglucose (FDG) tracer shows certain limitations. Employing radioactively labelled glutamate derivatives for specific imaging of the truncated citrate cycle potentially allows more specific tumour imaging. Radiation dosimetry of the novel tracer BAY 85-8050, a glutamate derivative, was calculated and the effective dose (ED) was compared with that of FDG.

Methods

Five healthy volunteers were included in the study. Attenuation-corrected whole-body PET/CT scans were performed from 0 to 90 min, at 120 and at 240 min after injection of 305.0?±?17.6 MBq of BAY 85-8050. Organs with moderate to high uptake at any of the imaging time points were used as source organs. Total activity in each organ at each time point was measured. Time–activity curves (TAC) were determined for the whole body and all source organs. The resulting TACs were fitted to exponential equations and accumulated activities were determined. OLINDA/EXM software was used to calculate individual organ doses and the whole-body ED from the acquired data.

Results

Uptake of the tracer was highest in the kidneys due to renal excretion of the tracer, followed by the pancreas, heart wall and osteogenic cells. The mean organ doses were: kidneys 38.4?±?11.2 μSv/MBq, pancreas 23.2?±?3.8 μSv/MBq, heart wall 17.4?±?4.1 μSv/MBq, and osteogenic cells 13.6?±?3.5 μSv/MBq. The calculated ED was 8.9?±?1.5 μSv/MBq.

Conclusion

Based on the distribution and dose estimates, the calculated radiation dose of BAY 85-8050 is 2.67?±?0.45 mSv at a patient dose of 300 MBq, which compares favourably with the radiation dose of FDG (5.7 mSv).     

Influence of estrous cycle and estradiol on behavioral sensitization to cocaine in female rats

The hypotheses that the estrous cycle and estradiol modulate behavioral sensitization to cocaine in female rats were assessed. In an analysis of sensitization across the estrous cycle, female rats were administered saline or cocaine (15 mg/kg) twice daily for 5 days. Sensitization developed in the intact female rats as measured by the significant increase in stimulant behaviors seen between day 1 and day 5 of treatment. Rats were challenged with cocaine (5 mg/kg) at 3 days following discontinuation of drug treatment. The expression of sensitization as measured between cocaine and saline-treated rats was evident only in female rats in diestus at the time of the challenge test with cocaine. To explore the role of estradiol in sensitization, female rats were ovariectomized or ovariectomized and implanted with estradiol for two weeks prior to treatment with cocaine (15 mg/kg) twice daily for 5 days. Sensitization developed in both ovariectomized and ovariectomized+estradiol rats treated with cocaine as measured by the significant increase in stimulant-like behaviors seen between day 1 and day 5 of treatment. Rats were challenged with 5 mg/kg of cocaine at 3, 13 and 34 days following discontinuation of drug treatment. While neither hormone treatment group exposed to the cocaine regimen expressed sensitization at 3 days of withdrawal, both groups exhibited sensitization at 13 and 34 days following discontinuation of cocaine treatment. The estradiol-treated groups exhibited higher levels of activity relative to their untreated cohorts in both saline or cocaine treatment groups. These results suggest that detection of sensitization in female rats is not only influenced by injection regimen and length of abstinence but also by the presence of estrogens which effectively enhance the response to an acute cocaine challenge in the presence or absence of prior cocaine exposure.     

Clinical and image-guided chorioretinal findings in long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency

The purpose of this study is to report clinical, optical coherence tomography (OCT), and fluorescein angiogram/indocyanine green angiography (FA/ICG) findings in patients with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) enzyme deficiency in two siblings. A 13-year-old girl and her 14-year-old brother presented with progressive decrease in central vision. Clinically, there were blond-looking fundi, diffuse retinal pigment epithelial (RPE) disruption/atrophy in the macula and peripheral retina with choriocapillaris atrophy in both of them. OCT showed RPE irregularity and diffuse disruption of the RPE layer. FA/ICG imaging demonstrated transmitted choroidal fluorescence secondary to diffuse RPE atrophy with no evidence of leakage. Electroretinogram and electrooculogram findings were suggestive of primary abnormality of pigment epithelium. The boy died of cardiac/respiratory illness, whereas his sister is alive at the last follow-up. Abnormal chorioretinal findings in LCHAD patients should be carefully followed. Regular follow-up is recommended to monitor the ocular and systemic status.     

Examining Sex Differences in Visual Reliance During Postural Control in Intercollegiate Athletes

BackgroundRisk factors for different sports injuries vary between sexes. Deficits in postural stability have been associated with several lower extremity injuries. The purpose of this study was to examine the differences in static postural stability between male and female intercollegiate athletes with and without visual information. # HypothesisThere will be no difference in visual reliance between sexes during static postural stability.Study DesignCross-sectional StudyMethodsStatic postural stability was assessed during a single session for football, soccer, basketball, and volleyball intercollegiate athletes (males, n=135, females, n=51) under eyes open (EO) and eyes closed (EC) conditions via performance of single limb stance on a force plate. Ground reaction force component data in all directions were quantified as a unitless composite score (COMP) where lower values indicated better postural stability. The absolute change and percentage change between EO and EC conditions were calculated for each sex. Two-sample Kolmogorov-Smirnov tests were used to compare differences between sexes.ResultsMales had greater EO COMP (males=7.77±3.40; females=6.48±4.61; p=0.038; Cohen’s d=0.343) and EC COMP (males=19.43±8.91; females 14.66±6.65; p=0.001; Cohen’s d=0.571) than females. A significant difference in absolute change from EO to EC was observed between sexes (males=-11.65±7.05; females=-8.18±5.61; p=0.01, Cohen’s d=-0.520) indicating that males had a greater change between conditions for the worse. There was no significant difference in percent change from EO to EC between sexes (males=159.2±90.7; females=156.7±109.2; p=0.39; Cohen’s d=0.026).ConclusionsThe observed differences between males and females in EO COMP, EC COMP, and absolute difference in COMP indicate that there is some factor that causes a difference in static postural stability between sexes. No difference in percent change between groups indicates that the difference in static postural stability between sexes may not be due to visual reliance. Female athletes may inherently have better postural stability than males, but both sexes were able to compensate for the loss of visual input.Level of Evidence3