Re-calculating! Navigating through the osteosarcoma treatment roadblock.

The survival rates for patients with osteosarcoma have remained almost static for the past three decades. Current standard of care therapy includes chemotherapies such as doxorubicin, cisplatin, and methotrexate along with complete surgical resection and surgery with or without ifosfamide and etoposide for relapse, though outcomes are hoped to be improved through clinical trials. Additionally, increased understanding of the genetics, signaling pathways and microenvironmental factors driving the disease have led to the identification of promising agents and potential paths towards translation of an exciting array of novel targeted therapies. Here, we review the mechanism of action of these emerging therapies and how, with clinical translation, they can potentially improve the survival rates for osteosarcoma patients in the near future.

The proof is in the pudding: children prefer lower fat but higher sugar than do mothers.

OBJECTIVE: Although there are established age-related differences in sweet preferences, it remains unknown whether children differ from mothers in their preference for and perception of fat (creaminess). We examined whether individual differences in sucrose and fat preferences and perception are related to age, genotype and lifestyle. SUBJECTS: Children 5-10 years-old (n=84) and their mothers (n=67) chose the concentration of sucrose and fat most preferred in pudding and sucrose most preferred in water using identical, two-alternative, forced-choice procedures, and ranked pudding samples for intensity of sweetness and creaminess. Subjects were also weighed and measured for height, as well as genotyped for a sweet-receptor gene (TAS1R3). RESULTS: Children preferred higher concentrations of sucrose in water (P=0.03) and in pudding (P=0.05) and lower concentrations of fat in pudding (P<0.01) than did mothers. Children and mothers were equally able to rank the intensity of different concentrations of fat (P=0.12) but not sucrose in pudding (P=0.01). Obese and lean children and mothers did not differ in preferences, but obese mothers were less able to correctly rank the concentration of fat in pudding than were lean mothers (P=0.03). Mothers who smoked preferred a higher concentration of sucrose than did those who never smoked (P<0.01). Individual differences in sweet preference were associated with genetic variation within the TAS1R3 gene in mothers but not children (P=0.04). CONCLUSION: Irrespective of genotype, children prefer higher concentrations of sugar but lower concentrations of fat in puddings than do their mothers. Thus, reduced-fat foods may be better accepted by children than adults.

NTRK-1 fusion in endocervical fibroblastic malignant peripheral nerve sheath tumor marking eligibility for larotrectinib therapy: A case report.

•<1% of cervical cancers are sarcomas.•Data on neurofibrosarcoma management is scarce.•Larotrectinib is approved for NTRK1 gene fusion tumors without acquired resistance.•Targeted therapy of tumor genes may expand treatment for a rare cervical sarcoma.

Polymorphisms in the taste receptor gene (Tas1r3) region are associated with saccharin preference in 30 mouse strains.

The results of recent studies suggest that the mouse Sac (saccharin preference) locus is identical to the Tas1r3 (taste receptor) gene. The goal of this study was to identify Tas1r3 sequence variants associated with saccharin preference in a large number of inbred mouse strains. Initially, we sequenced approximately 6.7 kb of the Tas1r3 gene and its flanking regions from six inbred mouse strains with high and low saccharin preference, including the strains in which the Sac alleles were described originally (C57BL/6J, Sac(b); DBA/2J, Sac(d)). Of the 89 sequence variants detected among these six strains, eight polymorphic sites were significantly associated with preferences for 1.6 mm saccharin. Next, each of these eight variant sites were genotyped in 24 additional mouse strains. Analysis of the genotype-phenotype associations in all 30 strains showed the strongest association with saccharin preference at three sites: nucleotide (nt) -791 (3 bp insertion/deletion), nt +135 (Ser45Ser), and nt +179 (Ile60Thr). We measured Tas1r3 gene expression, transcript size, and T1R3 immunoreactivity in the taste tissue of two inbred mouse strains with different Tas1r3 haplotypes and saccharin preferences. The results of these experiments suggest that the polymorphisms associated with saccharin preference do not act by blocking gene expression, changing alternative splicing, or interfering with protein translation in taste tissue. The amino acid substitution (Ile60Thr) may influence the ability of the protein to form dimers or bind sweeteners. Here, we present data for future studies directed to experimentally confirm the function of these polymorphisms and highlight some of the difficulties of identifying specific DNA sequence variants that underlie quantitative trait loci.

Extreme obesity may be linked to markers flanking the human OB gene.

Mice with mutations of the ob gene are extremely obese, and the human homologue (OB) has been cloned and physically mapped. The protein product of the ob gene (leptin) reduces body fat in mice when given exogenously, and leptin has been proposed to provide a lipostatic signal that regulates adiposity. Variation in the OB gene may be one genetically determined cause of obesity in human populations. To test this hypothesis, we genotyped siblings from 78 families at markers flanking the human OB gene. Pairs of siblings with extreme obesity (BMI > or = 40; n = 59) shared haplotypes identical-by-descent for the region containing the OB gene at greater than chance levels (corrected P = 0.04). Furthermore, one haplotype containing the OB gene was transmitted by heterozygous parents to extremely obese (BMI > or = 40) offspring more frequently than expected by chance, indicting significant allelic disequilibrium (corrected P = 0.027). One explanation for these linkage findings is that some individuals with extreme obesity have an allelic variant of the OB gene, although other nearby genes could contribute to obesity in these families.

A genome-wide scan suggests a locus on chromosome 1q21-q23 contributes to normal variation in plasma cholesterol concentration.

To identify genes that influence plasma cholesterol, triglyceride, and high-density and low-density lipoproteins concentrations we conducted a genome-wide scan using 354 polymorphic markers spaced at 10-cM intervals in 75 obese but otherwise normal human families. The results of the genome scan using sibling pair analysis of quantitative phenotypes suggested that 1q21-q23 contains a locus that influences plasma cholesterol concentration. Chromosome 12 gave evidence of linkage to plasma triglyceride concentration (D12SPAH) and chromosomes 3, 6, 7, 10, 11, 17, and 20 yielded additional evidence of linkage for lipid phenotypes at lower levels of statistical significance. Allele sharing for markers near prominent candidate genes was either very weakly related or unrelated to sibling similarity for lipid concentrations. Together these results suggest that genes with important roles in regulating normal cholesterol and triglyceride concentrations do not coincide with the location of previously known candidate genes.

Diagnostic assessment of osteosarcoma chemoresistance based on Virtual Clinical Trials.

Osteosarcoma is the most common primary bone tumor in pediatric and young adult patients. Successful treatment of osteosarcomas requires a combination of surgical resection and systemic chemotherapy, both neoadjuvant (prior to surgery) and adjuvant (after surgery). The degree of necrosis following neoadjuvant chemotherapy correlates with the subsequent probability of disease-free survival. Tumors with less than 10% of viable cells after treatment represent patients with a more favorable prognosis. However, being able to predict early, such as at the time of the pre-treatment tumor biopsy, how the patient will respond to the standard chemotherapy would provide an opportunity for more personalized patient care. Patients with unfavorable predictions could be studied in a protocol, rather than a standard setting, towards improving therapeutic success. The onset of necrotic cells in osteosarcomas treated with chemotherapeutic agents is a measure of tumor sensitivity to the drugs. We hypothesize that the remaining viable cells, i.e., cells that have not responded to the treatment, are chemoresistant, and that the pathological characteristics of these chemoresistant tumor cells within the osteosarcoma pre-treatment biopsy can predict tumor response to the standard-of-care chemotherapeutic treatment. This hypothesis can be tested by comparing patient histopathology samples before, as well as after treatment to identify both morphological and immunochemical cellular features that are characteristic of chemoresistant cells, i.e., cells that survived treatment. Consequently, using computational simulations of dynamic changes in tumor pathology under the simulated standard of care chemotherapeutic treatment, one can couple the pre- and post-treatment morphological and spatial patterns of chemoresistant cells, and correlate them with patient clinical diagnoses. This procedure, that we named 'Virtual Clinical Trials', can serve as a potential predictive biomarker providing a novel value-added decision support tool for oncologists.

Hydrogen-deuterium exchange at non-labile sites: a new reaction facet with broad implications for structural and dynamic determinations.

Hydrogen-deuterium exchange at non-labile sites is reported. The conjugate bases of isophthalic acid (m-C6H4(CO2H)2), 2-oxoglutaric acid (HO2CCOCH2CH2CO2H), and 2-methylisophthalic acid (2-CH3-1,3-C6H4(CO2H)2) undergo scrambling with 1, 2, and 3 carbon-centered hydrogens under a variety of conditions. Likewise, protonated 2-(m-methoxyphenyl)-ethylamine ((m-CH3OC6H4)CH2CH2NH2) undergoes up to 5 H/D exchanges upon gentle activation whereas the conjugate acid of 2-phenylethylamine (C6H5CH2CH2NH2) requires the presence of ammonia-d3 in order to be pushed to undergo up to 8 H/D exchanges. The very act of electrospraying ions can result in extensive movement of deuterium to carbon centers and, in some cases, could not be prevented. These findings offer great promise for future exploitation but also suggest that the interpretation of many H/D exchange experiments using mass spectrometry as the analytical tool could be in error.

X-linkage does not account for the absence of father-son similarity in plasma uric acid concentrations.

Plasma uric acid concentration aggregates in families, and this similarity has been suggested to be due, in part, to multiple shared genes. Men have higher plasma uric acid concentrations than women and are affected with gout nine times more frequently. Rare forms of hyperuricemia and gout are due to mutations of X-linked genes (HPRT1 and PRPS1). Given these observations, we tested the hypothesis that normal variation in plasma uric acid levels would display a pattern of familial similarity consistent with X-linkage in 892 individuals from 196 obese but otherwise healthy families. As predicted by X-linked inheritance, fathers and sons showed no resemblance in plasma uric acid concentration (r = 0.013, NS), while all other pairings showed moderate-to-strong familial resemblance (ranging from 0.167, P < 0.01, parent-offspring to 0.415, sister-sister, P < 0.01). We then tested the hypothesis that loci along the X chromosome would influence plasma uric acid concentration. We conducted both single-point and multipoint linkage analyses using 17 X-linked markers spaced at approximately 9 cm intervals to determine whether allele sharing among sibs was related to sib similarity in plasma uric acid concentrations (n = 1,100 sib pairs). We found no regions of the X chromosome that cosegregated with plasma uric acid concentrations (P > 0.05). We conclude that variation in genes on the X chromosome contribute little to normal variation in plasma uric acid concentrations.

Tolerance to hypothermia induced by ethanol depends on specific drug effects.

Two experiments were conducted to test the hypothesis that tolerance to the hypothermic effect of ethanol fails to develop if rats are denied the unconditional stimulus represented by hypothermia. In both experiments, rats were injected with either ethanol (1.9 or 2.5 g/kg) or saline and given microwave hyperthermia (MHT) to offset the hypothermic effect of the drug or sham-MHT. In one experiment, rats no longer demonstrated a hyperthermic response to a saline challenge after hypothermia was offset during 5 MHT treatment sessions. In a second experiment, rats prevented from becoming hypothermic did not develop tolerance to the hypothermic effect of ethanol due to MHT treatment, but did become tolerant to the ataxic effects of ethanol, which were unaffected by MHT. Results suggest that rats must experience the specific consequences of a drug to become tolerant to that effect.

Experimental determination of the alpha and beta C--H bond dissociation energies in naphthalene.

The acidities of the two different sites in naphthalene (1alpha and 1beta) and the electron affinities of the alpha- and beta-naphthyl radicals were measured using a Fourier transform mass spectrometer. Both carbon-hydrogen bond dissociation energies for naphthalene also were obtained, in this case via the application of a thermodynamic cycle. The final results are DeltaH(o)acid (1alpha) = 394.2+/-1.2 kcal mol(-1), DeltaH(o)acid (1beta) = 395.5+/-1.3 kcal mol(-1), EA(alpha) = 31.6+/-0.5 kcal mol(-1), EA(beta) = 31.6+/-0.5 kcal mol(-1), BDE(1alpha) = 112.2+/-1.3 kcal mol(-1) and BDE(1alpha) = 111.9+/-1.4 kcal mol(-1), and they are compared to benzene and phenyl radical as well as ab initio and density functional theory (B3LYP) calculations.

Sham-feeding of corn oil by rats: sensory and postingestive factors.

Previous research indicates that rats fed a high-fat (HF) diet increase their intake and preference for oil compared with rats fed a high-carbohydrate (HC) diet. To assess whether this increased intake was due to the sensory or postingestive properties of oil, rats were adapted to either the HF or HC diet and then allowed to sham-feed pure corn oil daily for 30 min. During the first 4 trials, rats fed the HF diet sham-fed more oil than did rats fed the HC diet; however, this difference diminished with repeated testing and was absent after 8 trials. In both diet groups, 4-5 calories (approximately 25%) of sham-fed oil could not be recovered and may have escaped to the intestine. These results suggest that, compared with rats fed a HC diet, rats fed a HF diet are initially attracted to the sensory properties of oil, but that the differential oil intakes of rats fed the HF or HC diet are maintained by postingestive, rather than sensory factors.

Nutrient preference and diet-induced adiposity in C57BL/6ByJ and 129P3/J mice.

Purified carbohydrates and fats are usually palatable to humans and other animals, and their consumption often induces weight gain and accumulation of fat. In this study, we examined consumption of complex carbohydrates (cornstarch and Polycose) and fats (soybean oil and margarine) in mice from two inbred strains, C57BL/6ByJ and 129P3/J. At lower concentrations of liquid nutrients tested using two-bottle tests, when the amounts consumed had negligible energy content, the C57BL/6ByJ mice had higher acceptance of Polycose and soybean oil. This was probably due to strain differences in chemosensory perception of Polycose and oil. At higher concentrations, the mice consumed a substantial part of their daily energy from the macronutrient sources, however, there were no or only small strain differences in nutrient consumption. These small differences were probably due to strain variation in body size. The two strains also did not differ in chow intake. Despite similar energy intakes, access to the nutrients resulted in greater body weight (BW) gain in the C57BL/6ByJ mice than in the 129P3/J mice. The diet-induced weight gain was examined in detail in groups of 2-month-old C57BL/6ByJ and 129P3/J mice given ether chow, or chow and margarine to eat. Access to margarine did not increase total energy consumption of either strain. It increased BW and adiposity of the C57BL/6ByJ mice, but only after they reached the age of approximately 3 months. There were no differences in BW and adiposity between control and margarine-exposed 129P3/J mice. The results suggest that diet-induced adiposity in the B6 mice depends on age and does not depend on hyperphagia.

Weight cycling in female rats increases dietary fat selection and adiposity.

The effect of repeated food restriction-refeeding (weight cycling) on macronutrient selection and adiposity was investigated in female Sprague-Dawley rats. Rats were maintained on ad lib macronutrient self-selection and were put on one of two types of restriction. One group was reduced to 75% of their body weight on restricted amounts of chow and a second group was given ad lib chow during the concurrent period and were voluntarily hypophagic. During refeeding on macronutrient self-selection, animals previously restricted selected a higher percentage of dietary fat, had larger adipose depots and plasma insulin values, and had lower heart weights both expressed in grams and as a percentage of body weight than non-restricted groups. This suggests that both severe and moderate periods of restriction may have negative health consequences.

Reduced mortality associated with body mass index (BMI) in African Americans relative to Caucasians.

Although obesity is especially common in African-American women, the relationship between body mass index (BMI, kg/m2) and mortality primarily has been studied in Caucasians, and almost exclusively in average weight populations. In order to examine the relationship between race and mortality in a predominately overweight population, we assessed mortality in 6,602 parents of obese African-American and Caucasian subjects. Most parents of both races were overweight or obese: 87.8% of African-American mothers (mean BMI = 37.7) and 78.6% of Caucasian mothers (mean BMI = 34.9) had a BMI > or =27.3; 61.9% of African-American fathers (mean BMI = 31.5) and 63.6% of Caucasian fathers (mean BMI = 31.8) had a BMI > or =27.8. Even though African Americans had equivalent (fathers) or higher (mothers) average BMI and percentage overweight or obesity than Caucasians, unadjusted mortality rates were consistently lower in African Americans than in Caucasians. In a combined sample, income, age (linear, quadratic and cubic effects), gender, BMI (linear and quadratic), and race were significant predictors of mortality. Linear and quadratic effects of BMI were significant within race and in the combined sample, after controlling for the effects of all other predictor variables. Therefore, the mortality differences cannot be due to differences in age, income, BMI, or gender distributions. In addition, there was significant heterogeneity between races for all models examined, suggesting interactions between race and all other predictor variables. Moreover, there was a strong residual effect for race after accounting for the other variables. The highly selective and cross-sectional nature of this sample limits our ability to make specific BMI-associated risk estimates. However, the consistent differences between comparably ascertained racial groups sampled from the upper extreme of the BMI distribution provide support for a lower BMI-associated mortality rate in African Americans relative to Caucasians.

Obesity: lessons from evolution and the environment.

The 9th Stock Conference acknowledged the complex background of genetic, cultural, environmental and evolutionary factors of obesity. Gene-environment interactions underlie the flexibility in body-weight and body-fat regulation, illustrated by the hunter-gatherers' feast and famine lifestyle, the variation in physical activity over the lifespan being highest at reproductive age, the variation in energy intake through 'eating in the absence of hunger', while running the risk of exceeding the capacity of triacylglyceride storage, leading to lipotoxicity and metabolic problems. Perinatal metabolic programming for obesity via epigenetic changes in response to a 'Western diet' results in production of lipid-poor milk and metabolically efficient pups, contributing to the perpetuation of obesity throughout generations. Evolutionary insight from comparative physiology and ecology indicates that over generations activity-induced energy expenditure has remained the same compared to wild mammals, that energy balance might be dependant on protein balance, while the function of taste changed from detection of poison or energy to social drinking and social behaviour. At present, the impact of assortative mating on obesity prevalence is unambiguously positive. The complexity that appeared can only be fully appreciated by setting the data into the context of our evolutionary history.

Calcium taste preferences: genetic analysis and genome screen of C57BL/6J x PWK/PhJ hybrid mice.

To characterize the genetic basis of voluntary calcium consumption, we tested C57BL/6J mice (B6; with low avidity for calcium), PWK/PhJ mice (PWK; with high avidity for calcium) and their F(1) and F(2) hybrids. All mice received a series of 96-h two-bottle preference tests with a choice between water and the following: 50 mm CaCl(2), 50 mm calcium lactate, 50 mm MgCl(2), 100 mm KCl, 100 mm NH(4)Cl, 100 mm NaCl, 5 mm citric acid, 30 microm quinine hydrochloride and 2 mm saccharin. Most frequency distributions of the parental and F(1) but not F(2) groups were normally distributed, and there were few sex differences. Reciprocal cross analysis showed that B6 x PWK F(1) mice had a non-specific elevation of fluid intake relative to PWK x B6 F(1) mice. In the F(2) mice, trait correlations were clustered among the divalent salts and the monovalent chlorides. A genome screen involving 116 markers showed 30 quantitative trait loci (QTLs), of which six involved consumption of calcium chloride or lactate. The results show pleiotropic controls of calcium and magnesium consumption that are distinct from those controlling consumption of monovalent chlorides or exemplars of the primary taste qualities.

Sham-feeding sucrose or corn oil stimulates food intake in rats.

In separate experiments, rats with open gastric cannulas were sham-fed either 32% sucrose solution or 15% corn oil emulsion. The rats' cannulas were then closed, and food intake was measured for 2 h. Food intake was greater after sham-feeding either fluid than after tests when no fluid was available. These results suggest that the oral stimulation produced by ingestion of sweet or oily fluids can stimulate appetite in the rat.

The genetics of phenylthiocarbamide perception.

The ability to taste the bitter compound phenylthiocarbamide (PTC) and related chemicals is bimodal, and all human populations tested to date contain some people who can and some people who cannot taste PTC. Why this trait has been maintained in the population is uncertain but this polymorphism may influence food selection, nutritional status or thyroid metabolism. The gene product that gives rise to this phenotype is unknown, and its characterization would provide insight into the mechanism of bitter taste perception. Although this trait is often considered a simple Mendelian trait, i.e. one gene two alleles, a recent linkage study found a major locus on chromosome 5p15 and evidence for an additional locus on chromosome 7. The development of methods to identify these genes will provide a good stepping-stone between single-gene disorders and polygenic traits.