Estrogen produces vasodilatation through the induction of nitric oxide synthase (NOS) in the endothelium, but there are many reports of endothelium-independent effects. In the present study, these processes were investigated in rat aortas isolated from ovariectomized rats. Long-term in vitro treatment with 17β-estradiol (10 nM for 24 h) in an organ culture system slightly reduced acetylcholine-mediated vasorelaxation in endothelium-intact aortic rings. 17β-Estradiol (1 and 10 nM for 24 h) also attenuated the phenylephrine-induced constriction in endothelium-denuded aortas, and this effect was inhibited by the NOS inhibitorl- N 5-(1-iminoethyl)ornithine hydrochloride, as well as the estrogen receptor antagonist ICI-182,780. Furthermore, 17β-estradiol treatment (1 and 10 nM for 24 h) increased nitric oxide production as assessed by the conversion of [3H]arginine to [3H]citrulline in endothelium-denuded rat aortas. These effects were prevented by the protein synthesis inhibitor cycloheximide. 17β-Estradiol (10 nM for 24 h) treatment also induced the formation of inducible NOS (iNOS) protein in aortas. The results indicate that 17β-estradiol can attenuate the vasoconstrictor effect of phenylephrine by a process that involves induction of iNOS in nonendothelial cells of the aorta. We suggest that long-term estrogen therapy may induce a partial hyporesponsiveness in vascular smooth muscle via a small but sustained nitric oxide production.

After endothelial damage in vivo, there is an induction of nitric oxide synthase (NOS) in the underlying smooth muscle cells. We hypothesized that intrinsic factors could induce NOS independently of blood elements. This was tested using an in vitro organ culture technique. Rat aortas with endothelium removed before 24-h organ culture (ERB) failed to constrict to phenylephrine after culture, whereas with endothelium removal after culture there was a normal constrictor response. Constrictor activity in ERB aortas was restored by the concomitant treatment with either the protein synthesis inhibitor cycloheximide (1 μM) or the NOS inhibitorl- N 5-(1-iminoethyl)ornithine hydrochloride (l-NIO, 100 μM). The ERB aortas also had an elevated NOS activity and induced NOS (iNOS) immunoreactivity. The constrictor response to phenylephrine in ERB aortas was only partially restored by acute application ofl-NIO subsequent to the 24-h organ culture, which suggests that other effects during culture contributed to the diminished tissue response. When ERB aortas were treated with reduced glutathione (GSH, 3 mM for 24 h), acute application of l-NIO then fully restored the constrictor effect. This suggests that peroxynitrite produced during culture may in part be responsible for loss of constrictor effects, and this was substantiated by the presence of nitrated tyrosine residues in aortic proteins and also widespread DNA damage, which was prevented by bothl-NIO and GSH. Thus some of the immediate (24-h) effects of endothelium removal involve intrinsic mechanisms resulting in iNOS synthesis, which leads to both nitric oxide and peroxynitrite generation, with resultant tissue damage and loss of contractile function.

1. It has been suggested that oestrogen-produced vasodilatation is due to induction of endothelial nitric oxide synthase (NOS), but there are many reports of direct effects on vascular smooth muscle. In the present study, these processes were investigated in rat aorta isolated from ovariectomized rats. 2. Short-term treatment (10 min) with 17beta-oestradiol (10 micromol/L) produced a small attenuation of the phenylephrine (PE)-induced constriction, which was unaffected by the nitric oxide synthase inhibitor L-N5(-1-iminoethyl)ornithine (NIO; 100 micromol/L). Long-term treatment (6 h) with 17beta-oestradiol (10 micromol/L) did not affect acetylcholine-mediated vasorelaxation in endothelium-intact aortic rings, but did attenuate PE-induced constriction. This attenuation was also observed in endothelium-denuded preparations after 17beta-oestradiol (10 micromol/L for 6 h) and was far greater than the acute effect of 17beta-oestradiol (10 micromol/L). 3. The attenuation produced by 17beta-oestradiol (10 micromol/L for 6 h) was significantly inhibited by concomitant treatment with cycloheximide (1 micromol/L), suggesting that protein synthesis was involved. NIO (100 micromol/L) also attenuated the effect, which suggests that the anti-constrictor effect of 17beta-oestradiol occurs through the increased production of nitric oxide (NO). 17Beta-oestradiol increased NO production, as assessed by the conversion of [3H]-arginine to [3H]-citrulline in rat aorta. These effects were prevented by cycloheximide and NIO. The anti-constrictor effect of oestrogen was blocked by the oestrogen receptor antagonist ICI 182 780 (100 nmol/L). 4. Western blotting using an antibody specific for inducible nitric oxide synthase (NOS) revealed that 17beta-oestradiol (10 micromol/L for 24 h) treatment induced the formation of inducible NOS protein in the aorta, an effect blocked by cycloheximide. The results indicate that 17beta-oestradiol can attenuate the vasoconstrictor effect of PE by a specific receptor-mediated process that involves induction of inducible NOS.

The global landscape of molecular testing is rapidly changing, with the recent publication of the International Association for the Study of Lung Cancer (IASLC)/College of American Pathologists (CAP) guidelines and the ALK Atlas. The IASLC/CAP guidelines recommend that tumors from patients with non-small cell lung cancer (NSCLC) be tested for ALK rearrangements in addition to epidermal growth factor receptor (EGFR) mutations. The spur for this recommendation is the availability of novel therapies that target these rearrangements. This article is based on coverage of a

Aim Palbociclib was approved in the United States in 2015 to treat estrogen receptor–positive/human epidermal growth factor receptor 2–negative (HER2–) advanced breast cancer (ABC). This study evaluated outcomes and safety in patients treated with palbociclib in Australia and India with hormone receptor–positive (HR+)/HER2– ABC before palbociclib became commercially available. Methods Postmenopausal women (≥18 years) with HR+/HER2– ABC who were appropriate candidates for letrozole therapy received palbociclib 125 mg once daily for 21 days followed by 7 days off, and letrozole 2.5 mg once daily (continuous). Safety, tumor response, and patient‐reported outcomes (Australian cohort) were evaluated. Results In total, 252 patients received palbociclib plus letrozole (Australia, n = 152; India, n = 100). More patients in the Australian versus Indian cohort had received prior chemotherapy (advanced/metastatic setting: 45.9% vs. 32.0%), endocrine therapy (advanced/metastatic setting: 63.2% vs. 54.3%), and advanced/metastatic therapies (61.8% vs. 31.0%). The most frequently reported all‐grade palbociclib‐related treatment‐emergent adverse events were neutropenia (66.7%), fatigue (35.3%), and stomatitis (26.6%); grade 3/4 neutropenia was reported as palbociclib‐related in 62.7% of patients. Febrile neutropenia was reported in six patients (2.4%). Eight patients (3.2%) discontinued because of an adverse event. The objective response rate was 19.4% (95% CI, 14.7%–24.9%) overall and 2.3% in Australian patients with ≥2 lines of prior therapy for metastatic disease. Patient‐reported quality of life scores were maintained throughout the study. Conclusions In an expanded access setting in Australia and India, palbociclib plus letrozole was well tolerated in patients with HR+/HER2– ABC, with a safety profile consistent with previous reports.