What information can we gain from performing adaptive radiotherapy of head and neck cancer patients from the past 10 years?

The aim of the review was to present the current literature status about replanning regarding anatomical and dosimetric changes in the target and OARs in the head and neck region during radiotherapy, to discuss and to analyze factors influencing the decision for adaptive radiotherapy of head and neck cancer patients. Significant progress has been made in head and neck patients' evaluation and qualification for adapted radiotherapy over the past ten years. Many factors leading to anatomical and dosimetric changes during treatment have been identified. Based on the literature, the most common factors triggering re-plan are weight loss, tumor and nodal changes, and parotid glands shrinkage. The fluctuations in dose distribution in the clinical area are significant predictive factors for patients' quality of life and the possibility of recovery. It has been shown that re-planning influence clinical outcomes: local control, disease free survival and overall survival. Regarding literature studies, it seems that adaptive radiotherapy would be the most beneficial for tumors of immense volume or those in the nearest proximity of the OARs. All researchers agree that the timing of re-planning is a crucial challenge, and there are still no clear consensus guidelines for time or criteria of re-planning. Nowadays, thanks to significant technological progress, the decision is mostly made based on observation and supported with IGRT verification. Although further research is still needed, adaptive strategies are evolving and now became the state of the art of modern radiotherapy.

GPR55 signalling promotes proliferation of pancreatic cancer cells and tumour growth in mice, and its inhibition increases effects of gemcitabine

The life expectancy for pancreatic cancer patients has seen no substantial changes in the last 40 years as very few and mostly just palliative treatments are available. As the five years survival rate remains around 5%, the identification of novel pharmacological targets and development of new therapeutic strategies are urgently needed. Here we demonstrate that inhibition of the G protein-coupled receptor GPR55, using genetic and pharmacological approaches, reduces pancreatic cancer cell growth in vitro and in vivo and we propose that this may represent a novel strategy to inhibit pancreatic ductal adenocarcinoma (PDAC) progression. Specifically, we show that genetic ablation of Gpr55 in the KRASWT/G12D/TP53WT/R172H/Pdx1-Cre+/+ (KPC) mouse model of PDAC significantly prolonged survival. Importantly, KPC mice treated with a combination of the GPR55 antagonist Cannabidiol (CBD) and gemcitabine (GEM, one of the most used drugs to treat PDAC), survived nearly three times longer compared to mice treated with vehicle or GEM alone. Mechanistically, knockdown or pharmacologic inhibition of GPR55 reduced anchorage-dependent and independent growth, cell cycle progression, activation of mitogen-activated protein kinase (MAPK) signalling and protein levels of ribonucleotide reductases in PDAC cells. Consistent with this, genetic ablation of Gpr55 reduced proliferation of tumour cells, MAPK signalling and ribonucleotide reductase M1 levels in KPC mice. Combination of CBD and GEM inhibited tumour cell proliferation in KPC mice and it opposed mechanisms involved in development of resistance to GEM in vitro and in vivo. Finally, we demonstrate that the tumour suppressor p53 regulates GPR55 protein expression through modulation of the microRNA miR34b-3p. Our results demonstrate the important role played by GPR55 downstream of p53 in PDAC progression. Moreover our data indicate that combination of CBD and GEM, both currently approved for medical use, might be tested in clinical trials as a novel promising treatment to improve PDAC patients' outcome.

Relationships between serum adiponectin and soluble TNF-α receptors and glucose and lipid oxidation in lean and obese subjects

Insulin resistance might be associated with an impaired ability of insulin to stimulate glucose oxidation and inhibit lipid oxidation. Insulin action is also inversely associated with TNF-α system and positively related to adiponectin. The aim of the present study was to analyze the associations between serum adiponectin, soluble TNF-α receptors concentrations and the whole-body insulin sensitivity, lipid and glucose oxidation, non-oxidative glucose metabolism (NOGM) and metabolic flexibility in lean and obese subjects. We examined 53 subjects: 25 lean (BMI < 25 kg × m(-2)) and 28 with overweight or obesity (BMI > 25 kg × m(-2)) with normal glucose tolerance. Hyperinsulinemic euglycemic clamp and indirect calorimetry were performed. An increase in respiratory exchange ratio in response to insulin was used as a measure of metabolic flexibility. Obese subjects had lower insulin sensitivity, adiponectin and higher sTNFR1 (all P < 0.001) and sTNFR2 (P = 0.001). Insulin sensitivity was positively related to adiponectin (r = 0.49, P < 0.001) and negatively related to sTNFR1 (r = -0.40, P = 0.004) and sTNFR2 (r = -0.52, P < 0.001). Adiponectin was related to the rate of glucose (r = 0.47, P < 0.001) and lipid (r = -0.40, P = 0.003) oxidation during the clamp, NOGM (r = 0.41, P = 0.002) and metabolic flexibility (r = 0.36, P = 0.007). Serum sTNFR1 and sTNFR2 were associated with the rate of glucose (r = -0.45, P = 0.001; r = -0.51, P < 0.001, respectively) and lipid (r = 0.52, P < 0.001; r = 0.46, P = 0.001, respectively) oxidation during hyperinsulinemia, NOGM (r = -0.31, P = 0.02; r = -0.43, P = 0.002, respectively) and metabolic flexibility (r = -0.47 and r = -0.51, respectively, both P < 0.001) in an opposite manner than adiponectin. Our data suggest that soluble TNF-α receptors and adiponectin have multiple effects on glucose and lipid metabolism in obesity.

The FTO gene modifies weight, fat mass and insulin sensitivity in women with polycystic ovary syndrome, where its role may be larger than in other phenotypes

AIM

Genome-wide association studies have shown that variation in the FTO gene predisposes to obesity and related traits that are common features of polycystic ovary syndrome (PCOS). The aim of the present study was to assess the effect of FTO variation on obesity, insulin sensitivity, and metabolic and hormonal profiles in PCOS.

METHODS

We examined 136 PCOS women (mean body mass index [BMI]: 28.28+/-6.95kg/m(2), mean age: 25.36+/-5.48 years). Anthropometric measurement, euglycaemic-hyperinsulinaemic clamp and oral glucose tolerance tests and sex hormone assessments were performed. The study group was genotyped for the FTO rs9939609 polymorphism.

RESULTS

BMI (29.0+/-6.9kg/m(2) vs 26.1+/-6.8kg/m(2); P=0.023), body weight (80.1+/-20.7kg vs 72.6+/-20.2kg; P=0.048), fat mass (29.7+/-1 6.6kg vs 24.6+/-17.7kg; P=0.045) and waist circumference (89.8+/-16.7cm vs 83.2+/-17.1cm; P=0.028) were higher in carriers of at least one copy of the A allele. Differences in these parameters were more significant when comparing AA and TT homozygotes. Women with the AA genotype also had decreased insulin sensitivity (P=0.025) and follicle-stimulating hormone (P=0.036). In logistic-regression analyses, the association of the FTO gene polymorphism with insulin sensitivity was no longer significant when BMI was included in the model.

CONCLUSION

Variation in the FTO gene modifies weight, adiposity and other measures of obesity and insulin sensitivity in PCOS. The examined FTO gene variant appears to have a greater impact on obesity and related traits in PCOS than in other phenotypes. The effect on insulin sensitivity appears to be secondary to its influence on obesity and body fat.

Increased skeletal muscle ceramide level in men at risk of developing type 2 diabetes

AIMS/HYPOTHESIS

Intramyocellular lipids, including ceramide, a second messenger in the sphingomyelin signalling pathway, might contribute to the development of insulin resistance. The aim of our study was to assess parameters of the skeletal muscle sphingomyelin signalling pathway in men at risk of developing type 2 diabetes.

METHODS

We studied 12 lean (BMI < 25 kg/m(2)) men without a family history of diabetes (control group), 12 lean male offspring of type 2 diabetic patients, and 21 men with overweight or obesity comprising 12 with NGT (obese-NGT) and nine with IGT (obese-IGT). A euglycaemic-hyperinsulinaemic clamp and a biopsy of vastus lateralis muscle were performed. Ceramide, sphingomyelin, sphinganine and sphingosine levels and sphingomyelinase and ceramidase activities were measured in muscle. Muscle diacylglycerol and triacylglycerol levels were estimated in a subgroup of 27 men (comprising men from all the above groups).

RESULTS

Compared with the control group, the lean offspring of diabetic patients and the men with overweight or obesity showed lower insulin sensitivity (all p < 0.005) and a greater muscle ceramide level (all p < 0.01). The obese-IGT group had lower insulin sensitivity (p = 0.0018) and higher muscle ceramide (p = 0.0022) than the obese-NGT group. There was lower muscle sphingosine level and alkaline ceramidase activity in offspring of diabetic patients (p = 0.038 and p = 0.031, respectively) and higher sphinganine level in the obese-NGT (p = 0.049) and obese-IGT (p = 0.002) groups than in the control group. Muscle sphingomyelin was lower (p = 0.0028) and neutral sphingomyelinase activity was higher (p = 0.00079) in the obese-IGT than in the obese-NGT group. Muscle ceramide was related to insulin sensitivity independently of other muscle lipid fractions.

CONCLUSIONS/INTERPRETATIONS

Ceramide accumulates in muscle of men at risk of developing type 2 diabetes.

Increased serum interleukin-18 concentration is associated with hypoadiponectinemia in obesity, independently of insulin resistance

OBJECTIVE

Interleukin-18 (IL-18) is a cytokine with proinflammatory and proatherogenic properties, which might be associated with the development of insulin resistance. In contrast, adiponectin, a protein secreted by adipose tissue, might exert insulin-sensitizing and antiatherogenic effects. The aim of the present study was to analyze the association between serum IL-18 and adiponectin in lean and obese subjects, in relation to insulin resistance.

DESIGN

Cross-sectional study.

SUBJECTS

One hundred and thirty individuals, 62 lean (body mass index (BMI)<25 kg/m(2), 30 men and 32 women) and 68 with overweight or obesity (BMI>25 kg/m(2), 24 men and 44 women), with normal glucose tolerance and without concomitant diseases.

MEASUREMENTS

Oral glucose tolerance test, euglycemic hyperinsulinemic clamp, serum concentrations of IL-18, IL-6, soluble tumor necrosis factor-alpha receptors and adiponectin.

RESULTS

Obese subjects had lower insulin sensitivity (M value, P=0.00029) and serum adiponectin (P=0.01) and higher levels of serum IL-18 (P=0.00055). Circulating IL-18 was negatively related to adiponectin (r=-0.31, P=0.00027) and insulin sensitivity (r=-0.33, P=0.00012). Subgroup analysis revealed that these associations were present in the obese (adiponectin, r=-0.38, P=0.0014; M, r=-0.29, P=0.016), but not in lean individuals (r=-0.17, P=0.18 and r=-0.20, P=0.12, respectively). Association of IL-18 with adiponectin remained significant after adjustment for other estimated parameters, including insulin sensitivity. Also, relationship between IL-18 and insulin sensitivity was independent of other estimated parameters.

CONCLUSION

Serum IL-18 is inversely related to serum adiponectin, independently of insulin resistance. The relationships of IL-18 with adiponectin and insulin sensitivity are influenced by the presence of overweight/obesity.