CD44 enhances tumor formation and lung metastasis in experimental osteosarcoma and is an additional predictor for poor patient outcome

Formation of metastases in the lungs is the major cause of death in patients suffering from osteosarcoma (OS). Metastases at presentation and poor response to preoperative chemotherapy are strong predictors for poor patient outcome. The elucidation of molecular markers that promote metastasis formation and/or chemoresistance is therefore of importance. CD44 is a plasma membrane glycoprotein that binds to the extracellular matrix component hyaluronan (HA) and has been shown to be involved in metastasis formation in a variety of other tumors. Here we investigated the role of CD44 expression on OS tumor formation and metastasis. High CD44 expression, evaluated with a tissue microarray including samples from 53 OS patients and stained with a pan‐CD44 antibody (Hermes3), showed a tendency (p < 0.08) to shortened overall survival. However, nonresponders and patients with lung metastases and high CD44 expression had significantly poorer prognosis than patients with low CD44 expression. Overexpression of the standard CD44 isoform (CD44s) and its HA‐binding defective mutant R41A in osteoblastic SaOS‐2 cells resulted in HA‐independent higher migration rates and increased chemoresistance, partially dependent on HA. In an orthotopic mouse model of OS, overexpression of CD44s in SaOS‐2 cells resulted in an HA‐dependent increased primary tumor formation and increased numbers of micrometastases and macrometastases in the lungs. In conclusion, although CD44 failed to be an independent predictor for patient outcome in this limited cohort of OS patients, increased CD44 expression was associated with even worse survival in patients with chemoresistance and with lung metastases. CD44‐associated chemoresistance was also observed in vitro, and increased formation of lung metastases was found in vivo in SCID mice. © 2013 American Society for Bone and Mineral Research.     

SNAP work requirements increase mental health care use

Objective

We measured the impact of Supplemental Nutrition Assistance Program (SNAP) work requirements on mental health care use.

Data Sources and Study Setting

We used 2015–2018 West Virginia Medicaid and SNAP data.

Study Design

Nine counties were exposed to SNAP work requirements. Using an event study framework, we assessed how this changed the probability and number of visits for depression and anxiety in the treatment versus the control group.

Data Collection/Extraction Methods

The sample included individuals aged 18–49, enrolled in both SNAP and Medicaid at the start of the study. Dually eligible individuals were excluded.

Principal Findings

At baseline, the probability of having a mood disorder visit was 6.1% among women and 5.3% among men, rising by 0.9 percentage points (SE 0.4, relative change +14.1%) among women and 0.7 percentage points (SE 0.3, relative change +13.0%) among men after exposure to work requirements. The probability of having an anxiety visit rose by 1.0 (SE 0.4) percentage points among women, a 17.8% relative increase over the baseline of 5.8%. Among men, the likelihood of having an anxiety visit increased by 1.0 percentage points (SE 0.5), a relative change of 24.3% over a baseline probability of 5.0%, though this effect occurred much more gradually compared to women.

Conclusions

Exposure to SNAP work requirements was associated with increases in health care use for mood disorders and anxiety among enrollees. The policy's effect differed between men and women.     

Metabolic clues regarding the enhanced performance of elite endurance athletes from orchiectomy-induced hormonal changes

This article examines the metabolic performance of an elite cyclist, Lance Armstrong, before and after his diagnosis with testicular cancer. Although a champion cyclist in 1-day events prior to his diagnosis of testicular cancer at age 25, he was not a contender in multi-day endurance cycle races such as the 3-week Tour de France. His genetic makeup and physiology (high VO2max, long femur, strong heavy build) coupled with his ambition and motivation enabled him at an early age to become one of the best 1-day cyclists in the world. Following his cancer diagnosis, he underwent a unilateral orchiectomy, brain surgery and four cycles of chemotherapy. After recovering, he returned to cycling and surprisingly excelled in the Tour de France, winning this hardest of endurance events 7 years running. This dramatic transformation from a 1-day to a 3-week endurance champion has led many to query how this is possible, and under the current climate, has led to suggestions of doping as to the answer to this metamorphosis. Physiological tests following his recovery indicated that physiological parameters such as VO2max were not affected by the unilateral orchiectomy and chemotherapy. We propose that his dramatic improvement in recovery between stages, the most important factor in winning multi-day stage races, is due to his unilateral orchiectomy, a procedure that results in permanent changes in serum hormones. These hormonal changes, specifically an increase in gonadotropins (and prolactin) required to maintain serum testosterone levels, alter fuel metabolism; increasing hormone sensitive lipase expression and activity, promoting increased free fatty acid (FFA) mobilization to, and utilization by, muscles, thereby decreasing the requirement to expend limiting glycogen stores before, during and after exercise. Such hormonal changes also have been associated with ketone body production, improvements in muscle repair and haematocrit levels and may facilitate the loss of body weight, thereby increasing power to weight ratio. Taken together, these hormonal changes act to limit glycogen utilization, delay fatigue and enhance recovery thereby allowing for optimal performances on a day-to-day basis. These insights provide the foundation for future studies on the endocrinology of exercise metabolism, and suggest that Lance Armstrong's athletic advantage was not due to drug use.     

Hair Mercury and Fish Consumption in Residents of O‘ahu,Hawai‘i

Recent studies have established that men are susceptible to cardiotoxicity from methylmercury exposure, which also poses risks to the pregnant woman. Hair samples were obtained and questionnaires for methylmercury exposure assessment were administered to 110 adults (57 men, 53 women) throughout O‘ahu, Hawai‘i during December 2010 to January 2011. Hair samples were analyzed for total mercury with a direct mercury analyzer. Men ≥ 46 years had a median of 2.0 µg/g, which was above the reference dose of 1 µg/g, as compared to younger men with a median 1.0 µg/g (P < 0.05). Hair concentrations from older women had a median of 1.2 µg/g of mercury compared to 0.6 µg/g for younger women. Additionally, 38% of women of childbearing age had a Hazard Index > 1.0. This indicates that both men and women were at risk for excessive methylmercury exposure. In the final regression model, male gender, age > 45 years, length of residency > 10 years in Hawai‘i, and fish consumption frequency > 1 meal per week were significant factors in increased hair mercury levels. Following safe fish consumption practices allows residents to reap health benefits of fish consumption without excessive toxicant exposure.     

Optimizing dose and scheduling of filgrastim (granulocyte colony- stimulating factor) for mobilization and collection of peripheral blood progenitor cells in normal volunteers [see comments]

To define an optimal regimen for mobilizing and collecting peripheral blood progenitor cells (PBPC) for use in allogeneic transplantation, we evaluated the kinetics of mobilization by filgrastim (recombinant met- human granulocyte colony-stimulating factor [r-metHuG-CSF]) in normal volunteers. Filgrastim was injected subcutaneously for up to 10 days at a dose of 3 (n = 10), 5 (n = 5), or 10 micrograms/kg/d (n = 15). A subset of volunteers from each dose cohort underwent a 7L leukapheresis on study day 6 (after 5 days of filgrastim). Granulocyte-macrophage colony-forming cell (GM-CFC) numbers in the blood were maximal after 5 days of filgrastim; a broader peak was evident for CD34+ cells between days 4 and 6. The 95% confidence intervals (CI) for mean number of PBPC per milliliter of blood in the three dose cohorts overlapped on each study day. However, on the peak day, CD34+ cells were significantly higher in the 10 micrograms/kg/d cohort than in a pool of the 3 and 5 micrograms/kg/d cohorts. Mobilization was not significantly influenced by volunteer age or sex. Leukapheresis products obtained at the 10 micrograms/kg/d dose level contained a median GM-CFC number of 93 x 10(4)/kg (range, 50 x 10(4)/kg to 172 x 10(4)/kg). Collections from volunteers receiving lower doses of filgrastim contained a median GM- CFC number of 36 x 10(4)/kg (range, 5 x 10(4)/kg to 204 x 10(4)/kg). The measurement of CD34+ cells per milliliter of blood on the day of leukapheresis predicted the total yield of PBPC in the leukapheresis product (r = .87, P < .0001). Assuming a minimum GM-CFC requirement of 50 x 10(4)/kg (based on our experience with autologous PBPC transplantation), all seven leukapheresis products obtained at the 10 micrograms/kg/d dose level were potentially sufficient for allogeneic transplantation purposes. We conclude that in normal donors, filgrastim 10 micrograms/kg/d for 5 days with a single leukapheresis on the following day is a highly effective regimen for PBPC mobilization and collection. Further studies are required to determine whether PBPC collected with this regimen reliably produce rapid and sustained engraftment in allogeneic recipients.     

Generation of normal human red cell volume, hemoglobin content, and membrane area distributions by "birth" or regulation?

Using flow cytometry and osmotic lysis measurements, we document here the means and coefficients of variation of the following red cell (RBC) properties: hemoglobin (Hb) content, volume, Hb concentration, and relative lytic tonicity distributions in populations of normal human RBCs, before and after density fractionation. The distributions showed a pattern characterized by much larger coefficients of variation of the Hb content and volume distributions than of the Hb concentration and relative lytic tonicity distributions. From analysis of the factors that determine those RBC properties, the patterns were interpreted as reflecting previously unrecognized statistical proportionalities between cell osmolyte content, Hb content, and membrane area. The possible origin of these statistical links was analyzed by considering alternative models with and without the participation of regulatory processes during cell maturation. A model was shown to be feasible in which mature RBC variability with proportional volume, area, and Hb content arises solely from cell size variability at the last erythroid cell division.     

Murine Hertwig's anemia: premature death after normal bone marrow transplantation is radiation dose-dependent

Marrow transplantation therapy in mice with heritable blood disorders usually leads to rapid blood cell normalization, but is sometimes followed by pancytopenia and premature death. This is especially true in mice with Hertwig's anemia (an/an). Unlike the +/+ recipients, 100% of whom survive for over a year, 66% of the mutant mice die by 6 months posttransplantation, and the rest die soon thereafter. It is not clear whether premature death is due to the radiation dose (10 Gy) or to the fact that the F1 mutant mice receive parental-type cells known to induce hybrid resistance. In the present report, experiments were designed to determine whether the F1-an/an host is more sensitive to radiation and/or resistant to continued expansion of the parental-type +/+ cells. The mutant mice are, indeed, more sensitive to irradiation, with an LD100/30 of 7 Gy as compared with an LD100/30 of 10 Gy for the +/+ mice. The times of anemia onset and death for mutant mice implanted with +/+ cells postirradiation is also radiation dose-dependent. Further evidence that death is due to host radiation damage rather than F1 hybrid resistance was provided by transplanting cells from three morbid 10 Gy-irradiation recipients into unirradiated, anemic, stem cell-deficient, F1-W/Wv secondary hosts. All recipients were repopulated by the original parental cells, were cured of their anemia, and survived for 52 weeks posttransplantation. The an/an mouse's heightened susceptibility to radiation damage appears to be the major factor in early death after transplantation therapy.     

Expression of bcr-abl abrogates factor-dependent growth of human hematopoietic M07E cells by an autocrine mechanism

The introduction of a retrovirus vector expressing p210bcr-abl (P210) into the human factor-dependent cell line M07E resulted in the rapid outgrowth of factor-independent cells. Early after infection, four factor-independent clones were isolated and analyzed in greater detail along with mass populations obtained from separate infections. High levels of P210 tyrosine kinase activity were measured in the factor- independent cells. The mass populations and three of the four clones remained responsive to exogenous growth factors. Concentrated conditioned media isolated from the factor-independent populations and from all clones contained biologically active granulocyte-macrophage colony-stimulating factor (GM-CSF); interleukin-3 (IL-3) was detected at low levels in the mass population and in two of the clones. Neutralizing antibodies to IL-3, GM-CSF, and mast cell growth factor inhibited proliferation of the factor responsive clones by 60% to 90%. These results indicate that the growth autonomy of the P210-expressing M07E cells was acquired via an autocrine mechanism. In addition to factor-independent growth, P210-expressing M07E cells readily acquired a more mature megakaryocytic phenotype compared with control M07E cells. These data provide experimental evidence that expression of P210 tyrosine kinase in human hematopoietic cells induced growth factor secretion resulting in a pleiotropic effect on growth factor dependence and differentiation.