The neuronal metabolite NAA regulates histone H3 methylation in oligodendrocytes and myelin lipid composition.

The neuronal mitochondrial metabolite N-acetylaspartate (NAA) is decreased in the multiple sclerosis (MS) brain. NAA is synthesized in neurons by the enzyme N-acetyltransferase-8-like (NAT8L) and broken down in oligodendrocytes by aspartoacylase (ASPA) into acetate and aspartate. We have hypothesized that NAA links the metabolism of axons with oligodendrocytes to support myelination. To test this hypothesis, we performed lipidomic analyses using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-performance thin-layer chromatography (HPTLC) to identify changes in myelin lipid composition in postmortem MS brains and in NAT8L knockout (NAT8L-/-) mice which do not synthesize NAA. We found reduced levels of sphingomyelin in MS normal appearing white matter that mirrored decreased levels of NAA. We also discovered decreases in the amounts of sphingomyelin and sulfatide lipids in the brains of NAT8L-/- mice compared to controls. Metabolomic analysis of primary cultures of oligodendrocytes treated with NAA revealed increased levels of α-ketoglutarate, which has been reported to regulate histone demethylase activity. Consistent with this, NAA treatment resulted in alterations in the levels of histone H3 methylation, including H3K4me3, H3K9me2, and H3K9me3. The H3K4me3 histone mark regulates cellular energetics, metabolism, and growth, while H3K9me3 has been linked to alterations in transcriptional repression in developing oligodendrocytes. We also noted the NAA treatment was associated with increases in the expression of genes involved in sulfatide and sphingomyelin synthesis in cultured oligodendrocytes. This is the first report demonstrating that neuronal-derived NAA can signal to the oligodendrocyte nucleus. These data suggest that neuronal-derived NAA signals through epigenetic mechanisms in oligodendrocytes to support or maintain myelination.

Phase III pilot study of dose escalation using conformal radiotherapy in prostate cancer: PSA control and side effects.

Radical radiotherapy is a standard form of management of localised prostate cancer. Conformal treatment planning spares adjacent normal tissues reducing treatment-related side effects and may permit safe dose escalation. We have tested the effects on tumour control and side effects of escalating radiotherapy dose and investigated the appropriate target volume margin. After an initial 3-6 month period of androgen suppression, 126 men were randomised and treated with radiotherapy using a 2 by 2 factorial trial design. The initial radiotherapy tumour target volume included the prostate and base of seminal vesicles (SV) or complete SV depending on SV involvement risk. Treatments were randomised to deliver a dose of 64 Gy with either a 1.0 or 1.5 cm margin around the tumour volume (1.0 and 1.5 cm margin groups) and also to treat either with or without a 10 Gy boost to the prostate alone with no additional margin (64 and 74 Gy groups). Tumour control was monitored by prostate-specific antigen (PSA) testing and clinical examination with additional tests as appropriate. Acute and late side effects of treatment were measured using the Radiation Treatment and Oncology Groups (RTOG) and LENT SOM systems. The results showed that freedom from PSA failure was higher in the 74 Gy group compared to the 64 Gy group, but this did not reach conventional levels of statistical significance with 5-year actuarial control rates of 71% (95% CI 58-81%) in the 74 Gy group vs 59% (95% CI 45-70%) in the 64 Gy group. There were 23 failures in the 74 Gy group and 33 in the 64 Gy group (Hazard ratio 0.64, 95% CI 0.38-1.10, P=0.10). No difference in disease control was seen between the 1.0 and 1.5 cm margin groups (5-year actuarial control rates 67%, 95% CI 53-77% vs 63%, 95% CI 50-74%) with 28 events in each group (Hazard ratio 0.97, 95% CI 0.50-1.86, P=0.94). Acute side effects were generally mild and 18 weeks after treatment, only four and five of the 126 men had persistent > or =Grade 1 bowel or bladder side effects, respectively. Statistically significant increases in acute bladder side effects were seen after treatment in the men receiving 74 Gy (P=0.006), and increases in both acute bowel side effects during treatment (P=0.05) and acute bladder sequelae (P=0.002) were recorded for men in the 1.5 cm margin group. While statistically significant, these differences were of short duration and of doubtful clinical importance. Late bowel side effects (RTOG> or =2) were seen more commonly in the 74 Gy and 1.5 cm margin groups (P=0.02 and P=0.05, respectively) in the first 2 years after randomisation. Similar results were found using the LENT SOM assessments. No significant differences in late bladder side effects were seen between the randomised groups using the RTOG scoring system. Using the LENT SOM instrument, a higher proportion of men treated in the 74 Gy group had Grade > or =3 urinary frequency at 6 and 12 months. Compared to baseline scores, bladder symptoms improved after 6 months or more follow-up in all groups. Sexual function deteriorated after treatment with the number of men reporting some sexual dysfunction (Grade> or =1) increasing from 38% at baseline to 66% at 6 months and 1 year and 81% by year 5. However, no consistent differences were seen between the randomised groups. In conclusion, dose escalation from 64 to 74 Gy using conformal radiotherapy may improve long-term PSA control, but a treatment margin of 1.5 cm is unnecessary and is associated with increased acute bowel and bladder reactions and more late rectal side effects. Data from this randomised pilot study informed the Data Monitoring Committee of the Medical Research Council RT 01 Trial and the two studies will be combined in subsequent meta-analysis.

High activity Rhenium-186 HEDP with autologous peripheral blood stem cell rescue: a phase I study in progressive hormone refractory prostate cancer metastatic to bone.

We tested the feasibility and toxicity of high activities Rhenium-186 hydroxyethylidene diphosphonate, with peripheral blood stem cell rescue in patients with progressive hormone refractory prostate cancer metastatic to bone. Twenty-five patients received between 2500 and 5000 MBq of Rhenium-186 hydroxyethylidene diphosphonate followed 14 days later by the return of peripheral blood peripheral blood stem cells. Activity limiting toxicity was defined as grade III haematological toxicity, lasting at least 7 days, or grade IV haematological toxicity of any duration or any serious unexpected toxicity. Activity limiting toxicity occurred in two of six who received activities of 5000 MBq and maximum tolerated activity was defined at this activity level. Prostate specific antigen reductions of 50% or more lasting at least 4 weeks were seen in five of the 25 patients (20%) all of whom received more than 3500 MBq of Rhenium-186 hydroxyethylidene diphosphonate. The actuarial survival at 1 year is 54%. Administered activities of 5000 MBq of Rhenium-186 hydroxyethylidene diphosphonate are feasible using autologous peripheral blood peripheral blood stem cell rescue in patients with progressive hormone refractory prostate cancer metastatic to bone. The main toxicity is thrombocytopaenia, which is short lasting. A statistically significant activity/prostate specific antigen response was seen. We have now commenced a Phase II trial to further evaluate response rates.

Recovery of serum testosterone, LH and FSH levels following neoadjuvant hormone cytoreduction and radical radiotherapy in localized prostate cancer.

This study was carried out to evaluate the possible long-term endocrine effect of short-term neoadjuvant leuteinizing hormone-releasing hormone analogue (LHRHa) administration in localized prostate cancer. A total of 419 men were treated for 3-6 months at The Royal Marsden NHS Trust by neoadjuvant androgen suppression using monthly depot injections of LHRHa before radical radiotherapy. Serum testosterone (852 measurements), leuteinizing hormone (LH) (799 measurements), and follicle-stimulating hormone (FSH) levels (801 measurements) were grouped according to their timing in relation to hormonal treatment and then analysed. Suppression of pituitary gonadotrophins and testosterone after the administration of LHRHa and their recovery after cessation of the drug was clearly observed. Median serum testosterone levels decreased from 16 nmol/l to 14 nmol/l when comparing prehormonal and follow-up phases. The same comparison showed an increase in median serum LH and FSH levels, with the median LH rising from 5 u/l to 8 u/l and the median serum FSH rising from 6 u/l to 20 u/l. On long-term follow-up, three of 256 men have remained with testosterone levels in the castrate range. Similar highly significant results were seen in subgroup of 103 men who had both pre-LHRHa and follow-up hormone levels analysed (P=0.012, P<0.001, P<0.001 for testosterone, LH and FSH respectively). Our data suggest the possibility of residual gonadal dysfunction after short-term LHRHa administration and radical radiotherapy in localized prostate cancer. Serum testosterone levels are restored to normal levels in the majority of patients, with a compensatory increase in serum levels of LH.

A pilot study of intermittent androgen deprivation in advanced prostate cancer.

OBJECTIVE: To assess the feasibility of intermittent hormone therapy for metastatic prostate cancer. PATIENTS AND METHODS: Sixteen patients with metastatic carcinoma of the prostate were treated using a protocol of intermittent hormone therapy with the luteinizing hormone-releasing hormone (LHRH) analogue leuprorelin at a dose of 3.75 mg every 4 weeks. The protocol required that hormone therapy be stopped when the response was stable, and was designed to assess the duration of the unmaintained response and the probability of a second response to re-initiation of leuprorelin. RESULTS: Eleven of the 16 patients had a stable hormone response and stopped therapy 3-9 months (mean 5.5) from the start of treatment. The mean (range) duration of the unmaintained response, as judged by monitoring symptoms and serum prostate specific antigen (PSA) levels every month was 4 (2-8) months in the seven patients who had bone metastases and was 3, 3 and 6 months in the three with only loco-regional disease (one patient temporarily discontinued follow-up). As the immediate re-induction of hormone therapy was not mandatory in asymptomatic patients at the time of progression, the mean (range) period off hormone therapy was 8 (3-13) months in those eight patients with bone metastases and was 3, 36 and 42 + months in the three presenting with loco-regional disease. All 10 patients who re-initiated hormone therapy had a second hormone response, in six of which led to a decline in PSA level to < 2 ng/mL. During the period off hormone therapy no patient developed irreversible symptoms. CONCLUSIONS: The temporary cessation of hormone therapy early during the response in patients with metastatic carcinoma of prostate is associated with biochemical evidence of relatively early progression in most cases, but can be associated with significant periods off therapy and with a high chance of a second hormone response. The value of this approach to the quality and duration of patients' lives requires a prospective comparative evaluation.

[Basic principles and initial results of adjuvant hormone therapy and irradiation of prostatic carcinoma]. / Grundprinzipien und erste Ergebnisse der adjuvanten Hormontherapie und Bestrahlung des Prostatakarzinoms.

Radiotherapy is an effective treatment for localized prostate cancer. A dose response relationship has been demonstrated for both local tumor control and complications. Reducing the volume of normal tissue treated may allow dose escalation without an increase in RT induced side effects. Androgen blockade before RT could, by reducing tumor volume, increase local control, disease-free (DFS) and overall survival in patients (pts) with prostatic adenocarcinoma. A total of 79 patients with T2-T4 prostate cancer have been treated initially with LHRH agonists and cyproterone acetate followed by radical irradiation between 1988 and 1993. The first cohort of 22 patients were monitored intensively by transrectal ultrasound and computed tomography. For each patient conformal photon beam radiotherapy and conventional treatment plans were produced and dose volume histograms compared for total volume, rectal volume, and bladder volume. Overall mean reduction of prostate volume was about 50%, and radiotherapy target volume was reduced by 37%. 53 further patients without clinical evidence of regional or distant metastases were given 3 months preradiotherapeutic hormonal cytoreduction with a short course of cyproterone acetate and LHRH. PSA level fell rapidly in most patients and after 3 months treatment the median PSA level was 1 ng/ml and 83% had PSA level 10 ng/ml. At 18 months PSA levels continued to be < 2 ng/ml in 70% of the patients. Combined modality treatment with the neoadjuvant or adjuvant androgen deprivation and conformal therapy show considerable promise as novel methods to improve the therapeutic ratio. This treatment approach may be used to explore the possibility of dose escalation in prostate cancer to enhance local control, and therapeutic randomised studies are underway to test these approaches.

Palliation of bone metastases in prostate cancer. Hemibody irradiation or strontium-89?

The palliation of bone pain is a common clinical problem once metastatic prostate cancer has escaped from hormonal control. This retrospective study compares the results of treatment using hemibody irradiation (HBI) at the Royal Marsden Hospital (27 cases) with isotope therapy using the bone-seeking isotope strontium-89 (89Sr) at Southampton General Hospital (51 cases). Prior to analysis patients were matched for potential prognostic factors (performance status, bone scan extent of disease, age, histology and duration of hormone response) to minimize the effect of treatment selection bias. Pain control assessed at 3 months was similar for HBI and matched 89Sr cases, with 63% and 52% respectively showing some benefit. Median survival was similar for these groups at 20 and 21 weeks respectively. The unmatched 89Sr group, which had more favourable prognostic factors, had a better outcome with 96% showing improvement in pain and with a median survival of 59 weeks. Subsequent univariate analysis demonstrated that performance status and extent of disease on bone scan were of overriding importance in determining outcome. Transfusion requirements were higher for the HBI group than for the matched 89Sr group (50% and 25% respectively) but other bone marrow toxicity was similar. Despite routine anti-emetic therapy 37% of patients treated with HBI had some nausea or vomiting. Although expensive, 89Sr appears as effective a treatment option as HBI. Response is most likely with either approach when patients have a good performance status and a limited extent of disease.