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Androgen receptors expressed by prostatic stromal cells obtained from younger versus older males exhibit opposite roles in prostate cancer progression.

ABSTRACT: Aging is a major risk factor for prostate cancer (PCa), and prostatic stromal cells may also promote PCa progression. Accordingly, stromal cells do not equally promote PCa in older males and younger males. Therefore, it is also possible that the expression of androgen receptors (ARs) by prostatic stromal cells in older versus younger males plays different roles in PCa progression. Using a gene knockdown technique and coculture system, we found that the knockdown of the AR in prostatic stromal cells obtained from younger males could promote the invasiveness and metastasis of cocultured PC3/LNCaP cells in vitro. By contrast, the invasiveness and metastasis of LNCaP cells was inhibited when cocultured with prostatic stromal cells from older males that when AR expression was knocked down. Moreover, after targeting AR expression with small hairpin RNA (shRNA), matrix metalloproteinase (MMP) expression in stromal cells was observed to increase in the younger group, but decreased or remained unchanged in the older group. One exception, however, was observed with MMP9. In vivo, after knocking down AR expression in prostatic stromal cells, the incidence of metastatic lymph nodes was observed to increase in the younger age group, but decreased in the older age group. Together, these data suggest that the AR in prostatic stromal cells played opposite roles in PCa metastasis for older versus younger males. Therefore, collectively, the function of the AR in prostatic stromal cells appears to change with age, and this may account for the increased incidence of PCa in older males.

SUBMITTER: Lu YY

PROVIDER: S-EPMC3881637 | biostudies-other | 2013 Sep

REPOSITORIES: biostudies-other

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Project description:Inadequate protein intake initiates an accommodative response with adverse changes in skeletal muscle function and structure. mRNA level changes due to short-term inadequate dietary protein might be an early indicator of accommodation. The aims of this study were to assess the effects of dietary protein and the diet-by-age interaction on the skeletal muscle transcript profile. Self-organizing maps were used to determine expression patterns across protein trials. 958 transcripts were differentially expressed (P<0.05) with diet and 853 had a diet-by-age interaction (P<0.05) using ANOVA. The results for diet alone revealed that P63 was associated with up-regulation of transcripts related to ubiquitin-dependent protein catabolism and muscle contraction and P63 and P94 resulted in up-regulation of transcripts related to apoptosis and down-regulation of transcripts related to cell differentiation; muscle and organ development; extracellular space; and responses to stimuli and stress. The diet-by-age expression patterns demonstrated that across the three protein trials transcripts related to protein metabolism were affected by age. Changes in skeletal muscle mRNA levels in the younger and older males to protein intake near or below the RDA are indicative of an early accommodative response. 5052 transcripts were determined as differentially expressed (P<0.05) between the younger and older males, of which 2556 met the False Discovery Rate correction (P=0.0081). The age-related changes in the transcript profile were consistent with aging skeletal muscle phenotypes including; mitochondrial dysfunction (UP- and DOWN-regulation), RNA splicing (UP), oxidative stress (UP), apoptosis (UP), and energy metabolism (DOWN). Experiment Overall Design: 22 healthy free-living younger (21-43 y, n=12) and older (63-79 y, n=10) males completed three controlled feeding trials with protein intakes of 63% (P63: 0.50 g/kg), 94% (P94: 0.75 g/kg), and 125% (P125: 1.00 g/kg) of the recommended dietary allowance (RDA). A fasting state vastus lateralis biopsy was taken from the dominant leg of each subject on day 12 of each trial following an overnight fast. Total RNA was isolated from the muscle samples using Tri-Reagent and the manufacture's protocol.

Project description:BackgroundDue to the interaction between skeletal muscle ageing and lifestyle factors, it is often challenging to attribute the decline in muscle mass and quality to either changes in lifestyle or to advancing age itself. Because many of the physiological factors affecting muscle mass and quality are modulated by physical activity and physical activity declines with age, the aim of this study is to better understand the effects of early ageing on muscle function by comparing a population of healthy older and young males with similar physical activity patterns.MethodsEighteen older (69 ± 2.0 years) and 20 young (22 ± 2.0 years) males were recruited based on similar self-reported physical activity, which was verified using accelerometry measurements. Gene expression profiles of vastus lateralis biopsies obtained by RNA sequencing were compared, and key results were validated using quantitative polymerase chain reaction and western blot.ResultsTotal physical activity energy expenditure was similar between the young and old group (404 ± 215 vs. 411 ± 189 kcal/day, P = 0.11). Three thousand seven hundred ninety-seven differentially expressed coding genes (DEGs) were identified (adjusted P-value cut-off of <0.05), of which 1891 were higher and 1906 were lower expressed in the older muscle. The matrisome, innervation and inflammation were the main upregulated processes, and oxidative metabolism was the main downregulated process in old compared with young muscle. Lower protein levels of mitochondrial transcription factor A (TFAM, P = 0.030) and mitochondrial respiratory Complexes IV and II (P = 0.011 and P = 0.0009, respectively) were observed, whereas a trend was observed for Complex I (P = 0.062), in older compared with young muscle. Protein expression of Complexes I and IV was significantly correlated to mitochondrial capacity in the vastus lateralis as measured in vivo (P = 0.017, R2 = 0.42 and P = 0.030, R2 = 0.36). A trend for higher muscle-specific receptor kinase (MUSK) protein levels in the older group was observed (P = 0.08).ConclusionsThere are clear differences in the transcriptome signatures of the vastus lateralis muscle of healthy older and young males with similar physical activity levels, including significant differences at the protein level. By disentangling physical activity and ageing, we appoint early skeletal muscle ageing processes that occur despite similar physical activity. Improved understanding of these processes will be key to design targeted anti-ageing therapies.

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Androgen receptors expressed by prostatic stromal cells obtained from younger versus older males exhibit opposite roles in prostate cancer progression.

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