Gene-expression profiling has had a considerable impact on our understanding of breast cancer biology. During the last 15 years, 5 intrinsic molecular subtypes of breast cancer (Luminal A, Luminal B, HER2-enriched, Basal-like and Claudin-low) have been identified and intensively studied. In this review, we will focus on the current and future clinical implications of the intrinsic molecular subtypes beyond the current pathological-based classification endorsed by the 2013 St. Gallen Consensus Recommendations. Within hormone receptor-positive and HER2-negative early breast cancer, the Luminal A and B subtypes predict 10-year outcome regardless of systemic treatment administered as well as residual risk of distant recurrence after 5 years of endocrine therapy. Within clinically HER2-positive disease, the 4 main intrinsic subtypes can be identified and dominate the biological and clinical phenotype. From a clinical perspective, patients with HER2+/HER2-enriched disease seem to benefit the most from neoadjuvant trastuzumab, or dual HER2 blockade with trastuzumab/lapatinib, in combination with chemotherapy, and patients with HER2+/Luminal A disease seem to have a relative better outcome compared to the other subtypes. Finally, within triple-negative breast cancer (TNBC), the Basal-like disease predominates (70-80%) and, from a biological perspective, should be considered a cancer-type by itself. Importantly, the distinction between Basal-like versus non-Basal-like within TNBC might predict survival following (neo)adjvuvant multi-agent chemotherapy, bevacizumab benefit in the neoadjuvant setting (CALGB40603), and docetaxel vs. carboplatin benefit in first-line metastatic disease (TNT study). Overall, this data suggests that intrinsic molecular profiling provides clinically relevant information beyond current pathology-based classifications.
We investigated the potency and the selectivity profile of vardenafil on phosphodiesterase (PDEs) enzymes, its ability to modify cGMP metabolism and cause relaxation of penile smooth muscle and its effect on erections in vivo under conditions of exogenous nitric oxide (NO) stimulation. PDE isozymes were extracted and purified from human platelets (PDE5) or bovine sources (PDEs 1, 2, 3, 4 and 6). The inhibition of these PDEs and of human recombinant PDEs by vardenafil was determined. The ability to potentiate NO-mediated relaxation and influence cGMP levels in human corpus cavernosum strips was measured in vitro, and erection-inducing activity was demonstrated in conscious rabbits after oral administration together with intravenous doses of sodium nitroprusside (SNP). The effects of vardenafil were compared with those of the well-recognized PDE5 inhibitor, sildenafil (values for sildenafil in brackets). Vardenafil specifically inhibited the hydrolysis of cGMP by PDE5 with an IC 50 of 0.7 nM (6.6 nM). In contrast, the IC 50 of vardenafil for PDE1 was 180 nM; for PDE6, 11 nM; for PDE2, PDE3 and PDE4, more than 1000 nM. Relative to PDE5, the ratios of the IC 50 for PDE1 were 257 (60), for PDE6 16 (7.4). Vardenafil significantly enhanced the SNP-induced relaxation of human trabecular smooth muscle at 3 nM (10 nM). Vardenafil also significantly potentiated both ACh-induced and transmural electrical stimulationinduced relaxation of trabecular smooth muscle. The minimum concentration of vardenafil that significantly potentiated SNP-induced cGMP accumulation was 3 nM (30 nM). In vivo studies in rabbits showed that orally administered vardenafil dose-dependently potentiated erectile responses to intravenously administered SNP. The minimal effective dose that significantly potentiated erection was 0.1 mg=kg (1 mg=kg). The selectivity for PDE5, the potentiation of NOinduced relaxation and cGMP accumulation in human trabecular smooth muscle and the ability to enhance NO-induced erection in vivo indicate that vardenafil has the appropriate properties to be a potential compound for the treatment of erectile dysfunction. Vardenafil was more potent and selective than sildenafil on its inhibitory activity on PDE5.
Introduction Diabetic men with erectile dysfunction (ED) are less responsive to therapy with type 5 phosphodiesterase (PDE5) inhibitors. Although an impairment of the nitric oxide (NO)/cyclic guanosin-monophosphate (cGMP) pathway has been shown in diabetic ED vs. non-diabetic ED, the functionality of NO/cGMP pathway in non-diabetic and diabetic ED patients with respect to non-ED patients has not been established. Aim The aim of this study is to evaluate the function of NO/cGMP signalling in human erectile tissues from ED patients exploring the added impact of diabetes. Methods Corpus cavernosum strips (human corpus cavernosum [HCC]) and penile resistance arteries (HPRA) were collected from penile specimens from organ donors (OD) and from diabetic and non-diabetic men with ED undergoing penile prosthesis implantation. Main Outcome Measures Relaxations to acetylcholine, electrical field stimulation, sodium nitroprusside, and sildenafil were evaluated in phenylephrine-contracted HCC and norepinephrine-contracted HPRA. cGMP content in HCC was also determined. Results The impairment of endothelium-dependent relaxation in HCC and HPRA from ED patients was exacerbated by diabetes (Emax 76.1, 62.9, and 49.3% in HCC and 73.1, 59.8, and 46.0% in HPRA from OD, non-diabetic and diabetic ED, respectively). Hypertension, hypercholesterolemia, or aging did not exert a further impairment of endothelial relaxation among ED patients. Diabetes also causes a further impairment of neurogenic relaxation in HCC and HPRA. The basal and stimulated content of cGMP in HCC was significantly decreased in patients with ED, but specially reduced in diabetic patients. Diabetes clearly impaired PDE5 inhibitor-induced vasodilation of HPRA from ED patients. Conclusions ED is related to impaired vasodilation, reduced relaxant capacity, and diminished cGMP content in penile tissue. These alterations are more severe in diabetes and accompany reduced relaxant efficacy of PDE5 inhibition. Thus, an exacerbated reduction of nitric oxide/cGMP signaling could be responsible for ED in diabetic men and would explain their reduced response to treatment.
BackgroundPredicting treatment benefit and/or outcome before any therapeutic intervention has taken place would be clinically very useful. Herein, we evaluate the ability of the intrinsic subtypes and the risk of relapse score at diagnosis to predict survival and response following neoadjuvant chemotherapy. In addition, we evaluated the ability of the Claudin-low and 7-TNBCtype classifications to predict response within triple-negative breast cancer (TNBC).MethodsGene expression and clinical-pathological data were evaluated in a combined dataset of 957 breast cancer patients, including 350 with TNBC, treated with sequential anthracycline and anti-microtubule-based neoadjuvant regimens. Intrinsic subtype, risk of relapse score based on subtype and proliferation (ROR-P), the Claudin-low subtype and the 7-TNBCtype subtype classification were evaluated. Logistic regression models for pathological complete response (pCR) and Cox models for distant relapse-free survival (DRFS) were used.ResultsBasal-like, Luminal A, Luminal B, and HER2-enriched subtypes represented 32.7 %, 30.6 %, 18.2 %, and 10.3 % of cases, respectively. Intrinsic subtype was independently associated with pCR in all patients, in hormone receptor-positive/HER2-negative disease, in HER2-positive disease, and in TNBC. The pCR rate of Basal-like disease was >35 % across all clinical cohorts. Neither the Claudin-low nor the 7-TNBCtype subtype classifications predicted pCR within TNBCs after accounting for intrinsic subtype. Finally, intrinsic subtype and ROR-P provided independent prognostic information beyond clinicopathological variables and type of pathological response. A 5-year DRFS of 97.5 % (92.8–100.0 %) was observed in these neoadjuvant-treated and clinically node-negative patients predicted to be low risk by ROR-P (i.e. 57.4 % of Luminal A tumors with clinically node-negative disease).ConclusionsIntrinsic subtyping at diagnosis provides prognostic and predictive information for patients receiving neoadjuvant chemotherapy. Although we could not exclude a survival benefit of neoadjuvant chemotherapy in patients with early breast cancer with clinically node-negative and ROR-low disease at diagnosis, the absolute benefit of cytotoxic therapy in this group might be rather small (if any).Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-015-0540-z) contains supplementary material, which is available to authorized users.
1 We have characterized the prostanoid receptors involved in the regulation of human penile arterial and trabecular smooth muscle tone. 2 Arachidonic acid induced relaxation of human corpus cavernosum strips (HCCS) that was blocked by the cyclo-oxygenase inhibitor, indomethacin, and augmented by the thromboxane receptor (TP) antagonist, SQ29548, suggesting that endogenous production of prostanoids regulates penile smooth muscle tone. 3 TP-receptors mediate contraction of HCCS and penile resistance arteries (HPRA), since the agonist of these receptors, U46619, potently contracted HCCS (EC 50 8.3+2.8 nM) and HPRA (EC 50 6.2+2.2 nM), and the contractions produced by prostaglandin F 2a at high concentrations (EC 50 6460+3220 nM in HCCS and 8900+6700 nM in HPRA) were inhibited by the selective TP-receptor antagonist, SQ29548 (0.02 mM). 4 EP-receptors are responsible for prostanoid-induced relaxant e ects in HCCS because only prostaglandin E 1 (PGE 1 ), prostaglandin E 2 and the EP 2 /EP 4 -receptor agonist, butaprost, produced consistent relaxation of this tissue (EC 50 93.8+31.5, 16.3+3.8 and 1820+1284 nM, respectively). In HPRA, both prostacyclin and PGE 1 (EC 50 60.1+18.4 and 109.0+30.9 nM, respectively) as well as the selective IP receptor agonist, cicaprost, and butaprost (EC 50 25.2+15.2 and 7050+6020 nM, respectively) caused relaxation, suggesting co-existence of IP-and EP-receptors (EP 2 and/or EP 4 ).
1 We have evaluated the participation of endothelium-derived hyperpolarizing factor (EDHF) in the endothelium-dependent relaxation of isolated human penile resistance arteries (HPRA) and human corpus cavernosum (HCC) strips. In addition, the effect of the angioprotective agent, calcium dobesilate (DOBE), on the endothelium-dependent relaxation of these tissues was investigated. 2 Combined inhibition of nitric oxide synthase (NOS) and cyclooxygenase (COX) nearly abolished the endothelium-dependent relaxation to acetylcholine (ACh) in HCC, while 60% relaxation of HPRA was observed under these conditions. Endothelium-dependent relaxation of HPRA resistant to NOS and COX inhibition was prevented by raising the extracellular concentration of K þ (35 mm) or by blocking Ca 2 þ -activated K þ channels, with apamin (APA; 100 nm) and charybdotoxin (CTX; 100 nm), suggesting the involvement of EDHF in these responses. 3 Endothelium-dependent relaxation to ACh was markedly enhanced by DOBE (10 mm) in HPRA but not in HCC. The potentiating effects of DOBE on ACh-induced responses in HPRA, remained after NOS and COX inhibition, were reduced by inhibition of cytochrome P450 oxygenase with miconazole (0.3 mm) and were abolished by high K þ or a combination of APA and CTX. 4 In vivo, DOBE (10 mg kg À1 i.v.) significantly potentiated the erectile responses to cavernosal nerve stimulation in male rats. 5 EDHF plays an important role in the endothelium-dependent relaxation of HPRA but not in HCC. DOBE significantly improves endothelium-dependent relaxation of HPRA mediated by EDHF and potentiates erectile responses in vivo. Thus, EDHF becomes a new therapeutic target for the treatment of erectile dysfunction (ED) and DOBE could be considered a candidate for oral therapy for ED.
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