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Treatment of breast cancer with aromatase inhibitors is associated with damage to bones. NCIC CTG MA.27 was an open-label, phase 3, randomised controlled trial in which women with breast cancer were assigned to one of two adjuvant oral aromatase inhibitors—exemestane or anastrozole. We postulated that exemestane—a mildly androgenic steroid—might have a less detrimental effect on bone than non-steroidal anastrozole. In this companion study to MA.27, we compared changes in bone mineral density (BMD) in the lumbar spine and total hip between patients treated with exemestane and patients treated with anastrozole. In MA.27, postmenopausal women with early stage hormone (oestrogen) receptor-positive invasive breast cancer were randomly assigned to exemestane 25 mg versus anastrozole 1 mg, daily. MA.27B recruited two groups of women from MA.27: those with BMD T-scores of −2·0 or more (up to 2 SDs below sex-matched, young adult mean) and those with at least one T-score (hip or spine) less than −2·0. Both groups received vitamin D and calcium; those with baseline T-scores of less than −2·0 also received bisphosphonates. The primary endpoints were percent change of BMD at 2 years in lumbar spine and total hip for both groups. We analysed patients according to which aromatase inhibitor and T-score groups they were allocated to but BMD assessments ceased if patients deviated from protocol. This study is registered with ClinicalTrials.gov, NCT00354302. Between April 24, 2006, and May 30, 2008, 300 patients with baseline T-scores of −2·0 or more were accrued (147 allocated exemestane, 153 anastrozole); and 197 patients with baseline T-scores of less than −2·0 (101 exemestane, 96 anastrozole). For patients with T-scores greater than −2·0 at baseline, mean change of bone mineral density in the spine at 2 years did not differ significantly between patients taking exemestane and patients taking anastrozole (−0·92%, 95% CI −2·35 to 0·50 vs −2·39%, 95% CI −3·77 to −1·01; p=0·08). Respective mean loss in the hip was −1·93% (95% CI −2·93 to −0·93) versus −2·71% (95% CI −4·32 to −1·11; p=0·10). Likewise for those who started with T-scores of less than −2·0, mean change of spine bone mineral density at 2 years did not differ significantly between the exemestane and anastrozole treatment groups (2·11%, 95% CI −0·84 to 5·06 vs 3·72%, 95% CI 1·54 to 5·89; p=0·26), nor did hip bone mineral density (2·09%, 95% CI −1·45 to 5·63 vs 0·0%, 95% CI −3·67 to 3·66; p=0·28). Patients with baseline T-score of −2·0 or more taking exemestane had two fragility fractures and two other fractures, those taking anastrozole had three fragility fractures and five other fractures. For patients who had baseline T-scores of less than −2·0 taking exemestane, one had a fragility fracture and four had other fractures, whereas those taking anastrozole had five fragility fractures and one other fracture. Our results demonstrate that adjuvant treatment with aromatase inhibitors can be considered for breast cancer patients who have T-scores less than −2·0. Canadian Cancer Society Research Institute, Pfizer, Canadian Institutes of Health Research.

Purpose Abiraterone is the active metabolite of the pro-drug abiraterone acetate (AA) and a selective inhibitor of CYP17, a key enzyme in testosterone synthesis, and improves overall survival in postdocetaxel metastatic castration-resistant prostate cancer (mCRPC). This open-label, single-arm phase 1b study was conducted to assess the effect of AA and abiraterone on the QT interval. Methods The study was conducted in 33 patients with mCRPC. Patients received AA 1,000 mg orally once daily + prednisone 5 mg orally twice daily. Electrocardiograms (ECGs) were collected in triplicate using 12-lead Holter monitoring. Baseline ECGs were obtained on Cycle 1 Day-1. Serial ECG recordings and time-matched pharmacokinetic (PK) blood samples were collected over 24 h on Cycle 1 Day 1 and Cycle 2 Day 1. Serial PK blood samples were also collected over 24 h on Cycle 1 Day 8. Results After AA administration, the upper bound of the 2-sided 90 % confidence interval (CI) for the mean baseline-adjusted QTcF change was <10 ms; no patients discontinued due to QTc prolongation or adverse events. No apparent relationship between change in QTcF and abiraterone plasma concentrations was observed [estimated slope (90 % CI): 0.0031 (−0.0040, 0.0102)]. Conclusions There is no significant effect of AA plus prednisone on the QT/QTc interval in patients with mCRPC.

Impaired apoptosis is one of the hallmarks of cancer. Caspase-3 and -8 are key regulators of the apoptotic response and have been shown to interact with the calpain family, a group of cysteine proteases, during tumorigenesis. The current study sought to investigate the prognostic potential of caspase-3 and -8 in breast cancer, as well as the prognostic value of combinatorial caspase and calpain expression. A large cohort (n = 1902) of early stage invasive breast cancer patients was used to explore the expression of caspase-3 and -8. Protein expression was examined using standard immunohistochemistry on tissue microarrays. High caspase-3 expression, but not caspase-8, is significantly associated with adverse breast cancer-specific survival ( P  = 0.008 and P  = 0.056, respectively). Multivariate analysis showed that caspase-3 remained an independent factor when confounding factors were included (hazard ratio (HR) 1.347, 95% confidence interval (CI) 1.086–1.670; P  = 0.007). The analyses in individual subgroups demonstrated the significance of caspase-3 expression in clinical outcomes in receptor positive (ER, PR or HER2) subgroups ( P  = 0.001) and in non-basal like subgroup (P  = 0.029). Calpain expression had been previously assessed. Significant association was also found between high caspase-3/high calpain-1 and breast cancer-specific survival in the total patient cohort ( P  = 0.005) and basal-like subgroup ( P  = 0.034), as indicated by Kaplan–Meier analysis. Caspase-3 expression is associated with adverse breast cancer-specific survival in breast cancer patients, and provides additional prognostic values in distinct phenotypes. Combinatorial caspase and calpain expression can predict worse prognosis, especially in basal-like phenotypes. The findings warrant further validation studies in independent multi-centre patient cohorts.

Background: Accumulating evidence demonstrates high levels of aldehyde dehydrogense (ALDH) activity in human cancer types, in part, because of its association with cancer stem cells. Whereas ALDH1A1 and ALDH7A1 isoforms were reported to associate with prostate tumorigenesis, whether other ALDH isoforms are associated with prostate cancer (PC) remains unclear. Methods: ALDH3A1 expression was analysed in various PC cell lines. Xenograft tumours and 54 primary and metastatic PC tumours were stained using immunohistochemistry for ALDH3A1 expression. Results: In comparison with the non-stem counterparts, a robust upregulation of ALDH3A1 was observed in DU145-derived PC stem cells (PCSCs). As DU145 PCSCs produced xenograft tumours with more advanced features compared with those derived from DU145 cells, higher levels of ALDH3A1 were detected in the former; a dramatic elevation of ALDH3A1 occurred in DU145 cell-derived lung metastasis compared with local xenograft tumours. Furthermore, while ALDH3A1 was not observed in prostate glands, ALDH3A1 was clearly present in PIN, and further increased in carcinomas. In comparison with the paired local carcinomas, ALDH3A1 was upregulated in lymph node metastatic tumours; the presence of ALDH3A1 in bone metastatic PC was also demonstrated. Conclusions: We report here the association of ALDH3A1 with PC progression.

The effect of anastrozole on peripheral and tumour aromatase activity and oestrogen levels in postmenopausal patients with oestrogen receptor-rich breast tumours was investigated. Twenty-six patients were randomly allocated to treatment with anastrozole 1 mg ( n =13) or 10 mg ( n =13), once daily. Before and after 12 weeks' treatment, patients were infused with 3 H-Δ 4 androstenedione (20 MBq) and 14 C-oestrone (E 1 ) (1 MBq) for 18 h. Oestrogens were purified from excised tumours and plasma samples taken after each infusion. Peripheral and tumour aromatase activity and tumour E 1 uptake were calculated from levels of 3 H and 14 C in purified E 1 fractions from tumour and plasma. Endogenous tumour oestrogens were measured by radioimmunoassay. Twenty-three patients were available for analysis (1 mg group, n =12; 10 mg group, n =11). Following treatment, anastrozole (1 and 10 mg) markedly inhibited peripheral aromatase in all patients (the difference between pre- and on-treatment values being highly significant P <0.0001). In situ aromatase activity was also profoundly decreased by anastrozole treatment in 16 of 19 tumours (the difference with treatment also being highly significant P =0.0009). Most tumours were able to concentrate E 1 beyond levels in the circulation; anastrozole treatment had no consistent effect on uptake of E 1 . Endogenous tumour levels of both E 1 and oestradiol (E 2 ) were significantly reduced with therapy ( P =0.028 for E 1 and P =0.0019 for E 2 ). Anastrozole (1 and 10 mg daily) effectively suppresses aromatase activity, and subsequently oestrogen levels, within the breast tissue of postmenopausal women with large or locally advanced, operable, oestrogen receptor-rich breast cancers.

Prostate cancer often relapses during androgen‐depletion therapy, even under conditions in which a drastic reduction of circulating androgens is observed. There is some evidence that androgens remain present in the tissues of hormone‐refractory prostate cancers (HRPC), and enzymes involved in the androgen and steroid metabolic pathway are likely to be active in HRPC cells. We previously carried out a genome‐wide gene expression profile analysis of clinical HRPC cells by means of cDNA microarrays in combination with microdissection of cancer cells and found dozens of transactivated genes. Among them, we here report the identification of a novel gene, SRD5A2L, encoding a putative 5α‐steroid reductase that produces the most potent androgen, 5α‐dihydrotestosterone (DHT), from testosterone. Liquid chromatography‐tandem mass spectrometry analysis following an in vitro 5α‐steroid reductase reaction validated its ability to produce DHT from testosterone, similar to type 1 5α‐steroid reductase. Because two types of 5α‐steroid reductase were previously reported, we termed this novel 5α‐steroid reductase ‘type 3 5α‐steroid reductase’ (SRD5A3). Reverse transcription–polymerase chain reaction and northern blot analyses confirmed its overexpression in HRPC cells, and indicated no or little expression in normal adult organs. Knockdown of SRD5A3 expression by small interfering RNA in prostate cancer cells resulted in a significant decrease in DHT production and a drastic reduction in cell viability. These findings indicate that a novel type 3 5α‐steroid reductase, SRD5A3, is associated with DHT production and maintenance of androgen–androgen receptor‐pathway activation in HRPC cells, and that this enzymatic activity should be a promising molecular target for prostate cancer therapy. (Cancer Sci 2008; 99: 81–86)

Aromatase converts androgens to estrogens. Although third-generation aromatase inhibitors (AIs) are important drugs in hormonal therapy for breast cancer in postmenopausal women, there are concerns about the side effects associated with the estrogen deprivation achieved with AIs. Expression of aromatase in breast cancer tissue is driven by different promoters than those in noncancer tissues; thus, suppression of aromatase expression in cancer tissues through the down-regulation of breast tumor-specific promoters would reduce the side effects associated with whole-body suppression of estrogen biosynthesis by AIs. We report that histone deacetylase inhibitor LBH589 (panobinostat) is a potent inhibitor of aromatase expression (with an IC₅₀ value < 25 nM). LBH589 selectively suppresses human aromatase gene promoters I.3/II, which are preferentially used in breast cancer tissue. Furthermore, using the H295R cell culture model, we found that achieving the same degree of inhibition of aromatase activity required only one-fifth as much letrozole (an AI) in the presence of 25 nM LBH589 as in the absence of LBH589. We also used an H295R/MCF7 coculture model to demonstrate the synergistic interaction of LBH589 + letrozole in suppressing the proliferation of hormone-responsive breast cancer cells. Finally, our results also indicate that LBH589 down-regulates the activity of promoters I.3/II in an epigenetic fashion. LBH589 reduces the levels of C/EBPδ, decreases the binding of C/EBPδ, and increases the levels and binding of acetyl-histones to the promoters I.3/II. These findings provide an important basis for future clinical evaluations of LBH589 in hormone-dependent breast cancer.

Breast cancer is the most common cancer in women worldwide. Hormone receptor breast cancers are the most common ones and, about 2 out of every 3 cases of breast cancer are estrogen receptor (ER) positive. Selective ER modulators, such as tamoxifen, are the first line of endocrine treatment of breast cancer. Despite the expression of hormone receptors some patients develop tamoxifen resistance and 50% present de novo tamoxifen resistance. Recently, we have demonstrated that activated mammalian target of rapamycin (mTOR) is positively associated with overall survival and recurrence free survival in ER positive breast cancer patients who were later treated with tamoxifen. Since altered expression of protein kinase B (PKB)/Akt in breast cancer cells affect N-myristoyltransferase 1 (NMT1) expression and activity, we investigated whether mTOR, a downstream target of PKB/Akt, regulates NMT1 in ER positive breast cancer cells (MCF7 cells). We inhibited mTOR by treating MCF7 cells with rapamycin and observed that the expression of NMT1 increased with rapamycin treatment over the period of time with a concomitant decrease in mTOR phosphorylation. We further employed mathematical modelling to investigate hitherto not known relationship of mTOR with NMT1. We report here for the first time a collection of models and data validating regulation of NMT1 by mTOR.

Purpose Clinical trials have reported conflicting results as to whether pre-operative aromatase inhibitors (AIs) improve outcome over pre-operative tamoxifen in postmenopausal women with hormone receptor-positive breast cancer. Methods We performed a meta-analysis comparing primary and secondary end points of pre-operative AI and pre-operative tamoxifen. The event-based risk ratio (RR) with 95% confidence intervals (95% Cis) were derived, and a test of heterogeneity was applied. Results Four studies (1,160 patients) met the inclusion criteria for the analysis. Meta-analysis showed that pre-operative AI was more effective than pre-operative tamoxifen. Pooled results of clinical efficacy were as follows: clinical objective response rate (RR, 1.29; 95% CI, 1.14–1.47; P  < 0.001), ultrasound objective response rate (RR, 1.29; 95% CI, 1.10–1.51; P  = 0.002), and breast conserving surgery (BCS) rate (RR, 1.36; 95% CI, 1.16–1.59; P  < 0.001). Hot flashes, nausea, and fatigue were not different between the pre-operative AI and pre-operative tamoxifen groups. Although headache was more frequent in the pre-operative AI group ( P  = 0.011), it was a manageable toxicity and was not clinically relevant. Conclusion Pre-operative AI has better BCS rate than tamoxifen and in terms of toxicities, is not inferior to tamoxifen; therefore, we could suggest pre-operative AI instead of tamoxifen for those postmenopausal patients with hormone receptor positive breast cancer, not eligible for chemotherapy.

Prostate specific antigen (PSA) or human kallikrein 3 (hK3) has long been an effective biomarker for prostate cancer. Now, other members of the tissue kallikrein (KLK) gene family are fast becoming of clinical interest due to their potential as prognostic biomarkers, particularly for hormone dependent cancers. The tissue kallikreins are serine proteases that are encoded by highly conserved multi-gene family clusters in rodents and humans. The rat and mouse loci contain 10 and 25 functional genes, respectively, while the human locus at 19q 13.4 contains 15 genes. The structural organization and size of these genes are similar across species; all genes have 5 coding exons that encode a prepro-enzyme. Although the physiological activators of these zymogens have not been described, in vitro biochemical studies show that some kallikreins can auto-activate and others can activate each other, suggesting that the kallikreins may participate in an enzymatic cascade similar to that of the coagulation cascade. These genes are expressed, to varying degrees, in a wide range of tissues suggesting a functional involvement in a diverse range of physiological and pathophysiological processes. These include roles in normal skin desquamation and psoriatic lesions, tooth development, neural plasticity, and Alzheimer's disease (AD). Of particular interest is the expression of many kallikreins in prostate, ovarian, and breast cancers where they are emerging as useful prognostic indicators of disease progression.