Towards Personalized Prostate Cancer Therapy Using Delta-Reachability Analysis

Recent clinical studies suggest that the efficacy of hormone therapy for prostate cancer depends on the characteristics of individual patients. In this paper, we develop a computational framework for identifying patient-specific androgen ablation therapy schedules for postponing the potential cancer relapse. We model the population dynamics of heterogeneous prostate cancer cells in response to androgen suppression as a nonlinear hybrid automaton. We estimate personalized kinetic parameters to characterize patients and employ $\delta$-reachability analysis to predict patient-specific therapeutic strategies. The results show that our methods are promising and may lead to a prognostic tool for personalized cancer therapy.Comment: HSCC 201

Dihydrotestosterone treatment rescues the decline in protein synthesis as a result of sarcopenia in isolated mouse skeletal muscle fibres

Background Sarcopenia, the progressive decline in skeletal muscle mass and function with age, is a debilitating condition. It leads to inactivity, falls, and loss of independence. Despite this, its cause(s) and the underlying mechanism(s) are still poorly understood. Methods In this study, small skeletal muscle fibre bundles isolated from the extensor digitorum longus (a fast-twitch muscle) and the soleus (a slow-twitch muscle) of adult mice of different ages (range 100–900 days old) were used to investigate the effects of ageing and dihydrotestosterone (DHT) treatment on protein synthesis as well as the expression and function of two amino acid transporters; the sodium-coupled neutral amino acid transporter (SNAT) 2, and the sodium-independent L-type amino-acid transporter (LAT) 2. Results At all ages investigated, protein synthesis was always higher in the slow-twitch than in the fast-twitch muscle fibres and decreased with age in both fibre types. However, the decline was greater in the fast-twitch than in the slow-twitch fibres and was accompanied by a reduction in the expression of SNAT2 and LAT2 at the protein level. Again, the decrease in the expression of the amino acid transporters was greater in the fast-twitch than in the slow-twitch fibres. In contrast, ageing had no effect on SNAT2 and LAT2 expressions at the mRNA level. Treating the muscle fibre bundles with physiological concentrations (~2 nM) of DHT for 1 h completely reversed the effects of ageing on protein synthesis and the expression of SNAT2 and LAT2 protein in both fibre types. Conclusion From the observations that ageing is accompanied by a reduction in protein synthesis and transporter expression and that these effects are reversed by DHT treatment, we conclude that sarcopenia arises from an age-dependent reduction in protein synthesis caused, in part, by the lack of or by the low bioavailability of the male sex steroid, DHT

Dihydrotestosterone stimulates amino acid uptake and the expression of LAT2 in mouse skeletal muscle fibres through an ERK1/2-dependent mechanism

Dihydrotestosterone (DHT) has acute/non-genomic actions in adult mammalian skeletal muscles whose physiological functions are still poorly understood. Therefore, the primary aim of this study was to investigate the acute/non-genomic effects of DHT on amino acid uptake as well as the cellular signal transduction events underlying these actions in mouse fast- and slow-twitch skeletal muscle fibre bundles. 14C-Labelled amino acids were used to investigate the effects of DHT and testosterone (T) on amino acid uptake and pharmacological interventions were used to determine the cellular signal transduction events mediating these actions. While T had no effect on the uptake of isoleucine (Ile) and a-methylaminoisobutyric acid (MeAIB) in both fibre types, DHT increased their uptake in the fast-twitch fibre bundles. This effect was reversed by inhibitors of protein translation, the epidermal growth factor receptor (EGFR), system A, system L, mTOR and MEK. However, it was relatively insensitive to inhibitors of transcription, androgen receptors and PI3K/Akt. Additionally, DHT treatment increased the expression of LAT2 and the phosphorylation of the EGFR in the fast-twitch fibre bundles and that of ERK1/2, RSK1/2 and ATF2 in both fibre types. Also, it decreased the phosphorylation of eEF2 and increased the incorporation of Ile into proteins in both fibre types. Most of these effects were reversed by EGFR and MEK inhibitors. From these findings we suggest that another physiological function of the acute/non-genomic actions of DHT in isolated mammalian skeletal muscle fibres is to stimulate amino acid uptake. This effect is mediated through the EGFR and involves the activation of the MAPK pathway and an increase in LAT2 expression

Objective treatment response to endocrine therapy in metastatic prostate cancer

A ten-year review of 198 patients with Stage D2 prostate cancer identified 13 patients (6.6%) who exhibited objective responses to hormonal treatment, as indicated by regression of a positive bone scan, CT scan, or chest x-ray film. Four patients had complete responses and 9 patients achieved partial responses as judged by the National Prostatic Cancer Project criteria. Median survival for those with objective treatment response has not yet been reached (>44 months) compared with twenty-four months for the nonresponders (p = 0.00006). Although relatively uncommon, objective treatment response in Stage D2 prostate cancer is correlated with an improved prognosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29756/1/0000094.pd

The Effects of Long-Term Sustained Delivery of Dihydrotestosterone by Poly(lactic acid) Impregnated and Noncoated Biodegradable Ceramic Devices in Male Rodents

The objectives of this investigation were to evaluate the release of dihydrotestosterone (DHT) from nonimpregnated and poly(lactic acid) (PLA) impregnated ALCAP ceramic reservoirs implanted in male rats, and to study the effects of delivered DHT on the reproductive system of male rats. A total of 120 Sprague-Dawley male albino rats were distributed equally into three groups. Two ALCAP capsules, one nonimpregnated and the other impregnated with PLA, were implanted in each rat in groups I and II. Capsules implanted in group I rats were loaded with 40 mg DHT each. Group II rats were implanted with two empty capsules (sham group), and group III animals served as un implanted controls. Eight rats from each group were euthanized at the end of the one, three, six, nine, and twelve months following the implantation of the ceramics. No significant changes in the weights of vital organs of rats were observed among any of the three different groups. Vas deferens and epididymal fluid were devoid of normal spermatozoa within three months of implanting the steroid-containing ceramics. Testes weights decreased significantly in the rats implanted with ALCAP ceramics containing DHT and the seminiferous tubules became oligospermic after one month and azoospermic after three months. The data collected in this study suggest that: (1) ALCAP ceramic cap sules are capable of delivering DHT for one year at a sustained manner; (2) DHT delivered by ALCAP capsules can be used effectively to regulate sperma togenesis in rats.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66739/2/10.1177_088391159100600201.pd

Activity and expression of progesterone metabolizing 5α-reductase, 20α-hydroxysteroid oxidoreductase and 3α(β)-hydroxysteroid oxidoreductases in tumorigenic (MCF-7, MDA-MB-231, T-47D) and nontumorigenic (MCF-10A) human breast cancer cells

BACKGROUND: Recent observations indicate that human tumorous breast tissue metabolizes progesterone differently than nontumorous breast tissue. Specifically, 5α-reduced metabolites (5α-pregnanes, shown to stimulate cell proliferation and detachment) are produced at a significantly higher rate in tumorous tissue, indicating increased 5α-reductase (5αR) activity. Conversely, the activities of 3α-hydroxysteroid oxidoreductase (3α-HSO) and 20α-HSO enzymes appeared to be higher in normal tissues. The elevated conversion to 5α-pregnanes occurred regardless of estrogen (ER) or progesterone (PR) receptor levels. To gain insight into these differences, the activities and expression of these progesterone converting enzymes were investigated in a nontumorigenic cell line, MCF-10A (ER- and PR-negative), and the three tumorigenic cell lines, MDA-MB-231 (ER- and PR-negative), MCF-7 and T-47D (ER- and PR-positive). METHODS: For the enzyme activity studies, either whole cells were incubated with [(14)C]progesterone for 2, 4, 8, and 24 hours, or the microsomal/cytosolic fraction was incubated for 15–60 minutes with [(3)H]progesterone, and the metabolites were identified and quantified. Semi-quantitative RT-PCR was employed to determine the relative levels of expression of 5αR type1 (SRD5A1), 5αR type 2 (SRD5A2), 20α-HSO (AKR1C1), 3α-HSO type 2 (AKR1C3), 3α-HSO type 3 (AKR1C2) and 3β-HSO (HSD3B1/HSD3B2) in the four cell lines using 18S rRNA as an internal control. RESULTS: The relative 5α-reductase activity, when considered as a ratio of 5α-pregnanes/4-pregnenes, was 4.21 (± 0.49) for MCF-7 cells, 6.24 (± 1.14) for MDA-MB-231 cells, 4.62 (± 0.43) for T-47D cells and 0.65 (± 0.07) for MCF-10A cells, constituting approximately 6.5-fold, 9.6-fold and 7.1 fold higher conversion to 5α-pregnanes in the tumorigenic cells, respectively, than in the nontumorigenic MCF-10A cells. Conversely, the 20α-HSO and 3α-HSO activities were significantly higher (p < 0.001) in MCF-10A cells than in the other three cell types. In the MCF-10A cells, 20α-HSO activity was 8-14-fold higher and the 3α-HSO activity was 2.5-5.4-fold higher than in the other three cell types. The values of 5αR:20α-HSO ratios were 16.9 – 32.6-fold greater and the 5αR:3α-HSO ratios were 5.2 – 10.5-fold greater in MCF-7, MDA-MB-231 and T-47D cells than in MCF-10A cells. RT-PCR showed significantly higher expression of 5αR1 (p < 0.001), and lower expression of 20α-HSO (p < 0.001), 3α-HSO2 (p < 0.001), 3α-HSO3 (p < 0.001) in MCF-7, MDA-MB-231 and T-47D cells than in MCF-10A cells. CONCLUSION: The findings provide the first evidence that the 5αR activity (leading to the conversion of progesterone to the cancer promoting 5α-pregnanes) is significantly higher in the tumorigenic MCF-7, MDA-MB-231 and T-47D breast cell lines than in the nontumorigenic MCF-10A cell line. The higher 5αR activity coincides with significantly greater expression of 5αR1. On the other hand, the activities of 20α-HSO and 3α-HSO are higher in the MCF-10A cells than in MCF-7, MDA-MB-231 and T-47D cells; these differences in activity correlate with significantly higher expression of 20α-HSO, 3α-HSO2 and 3α-HSO3 in MCF-10A cells. Changes in progesterone metabolizing enzyme expression (resulting in enzyme activity changes) may be responsible for stimulating breast cancer by increased production of tumor-promoting 5α-pregnanes and decreased production of anti-cancer 20α – and 3α-4-pregnenes

Influence of serum testosterone on urinary continence and sexual activity in patients undergoing radical prostatectomy for clinically localized prostate cancer

The aim of the present study was to evaluate how serum testosterone level (T) can affect urinary continence and erectile function in patients undergoing radical prostatectomy (RP). We included 257 patients with clinically localized prostate cancer, those who had filled out preoperative quality of life questionnaires (University of California, Los Angeles Prostate Cancer Index, International Index of Erectile Function (IIEF)), and those who had T and total PSA sampled the day before surgery. We calculated correlations between T and age, body mass index (BMI), PSA, urinary function or bother (UF, UB) and sexual function or bother (SF, SB) and IIEF-5 in the whole population and in sub-populations with normal (⩾10.4 nmol l−1) and low (<10.4 ng ml−1) T using Pearson's and Spearman's correlation coefficients. We evaluated differences in these parameters between patients with low and normal T using the unpaired samples t-test and Mann–Whitney test, and finally the correlation between UF and SF, UB and SB, and between PSA and T in the overall population, and separately in patients with low and normal T using the Pearson's correlation coefficient. Mean preoperative T was 13.5 nmol l−1 and 23.7% of patients presented a low T. Mean age, mean BMI and mean preoperative total PSA at RP were 64.3 years, 25.9 kg m−2 and 9.0 ng ml−1, respectively. BMI was negatively correlated with T in the overall population (r=−0.266; P=0.02); moreover, patients with normal T presented lower BMI compared with patients with low T (25.7 vs 27.6: P=0.02). We found a significant correlation between SF scores and T in patients with normal T (r=0.1777: P=0.05). SF was significantly higher in patients with normal T compared with those with low T (74.8 vs 64.8: P=0.05). Furthermore, UF and UB were significantly correlated with SF (r=0.2544: P<0.01) and SB (r=0.2512: P=0.01), respectively, in men with normal T. Serum T was significantly correlated with PSA in men with low T (r=0.3874: P=0.0029), whereas this correlation was missed in the whole population and in men with normal T. The correlation between preoperative PSA and T in men with low T is in agreement with the ‘saturation' model proposed by Morgentaler. The correlation between basal T and preoperative erectile function and urinary continence underlines the importance of assessing T before RP