The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.
If you have any questions or comments, please contact us.
BACKGROUND - Pulmonary fibrosis is a late manifestation of acute respiratory distress syndrome (ARDS). Sepsis is a major cause of ARDS, and its pathogenesis includes endotoxin-induced vascular injury. Recently, endothelial-to-mesenchymal transition (EndMT) was shown to play an important role in pulmonary fibrosis. On the other hand, dipeptidyl peptidase (DPP)-4 was reported to improve vascular dysfunction in an experimental sepsis model, although whether DPP-4 affects EndMT and fibrosis initiation during lipopolysaccharide (LPS)-induced lung injury is unclear. The aim of this study was to investigate the anti-EndMT effects of the DPP-4 inhibitor vildagliptin in pulmonary fibrosis after systemic endotoxemic injury.
METHODS - A septic lung injury model was established by intraperitoneal injection of lipopolysaccharide (LPS) in eight-week-old male mice (5 mg/kg for five consecutive days). The mice were then treated with vehicle or vildagliptin (intraperitoneally, 10 mg/kg, once daily for 14 consecutive days from 1 day before the first administration of LPS.). Flow cytometry, immunohistochemical staining, and quantitative polymerase chain reaction (qPCR) analysis was used to assess cell dynamics and EndMT function in lung samples from the mice.
RESULTS - Lung tissue samples from treated mice revealed obvious inflammatory reactions and typical interstitial fibrosis 2 days and 28 days after LPS challenge. Quantitative flow cytometric analysis showed that the number of pulmonary vascular endothelial cells (PVECs) expressing alpha-smooth muscle actin (α-SMA) or S100 calcium-binding protein A4 (S100A4) increased 28 days after LPS challenge. Similar increases in expression were also confirmed by qPCR of mRNA from isolated PVECs. EndMT cells had higher proliferative activity and migration activity than mesenchymal cells. All of these changes were alleviated by intraperitoneal injection of vildagliptin. Interestingly, vildagliptin and linagliptin significantly attenuated EndMT in the absence of immune cells or GLP-1.
CONCLUSIONS - Inhibiting DPP-4 signaling by vildagliptin could ameliorate pulmonary fibrosis by downregulating EndMT in systemic LPS-induced lung injury.
Increased oestrogen is a strong epidemiological risk factor for development of pulmonary arterial hypertension (PAH) in patients, associated with metabolic defects. In addition, oestrogens drive penetrance in mice carrying mutations in bone morphogenetic protein receptor type II (BMPR2), the cause of most heritable PAH. The goal of the present study was to determine whether inhibition of oestrogens was effective in the treatment of PAH in these mice.The oestrogen inhibitors fulvestrant and anastrozole were used in a prevention and treatment paradigm in BMPR2 mutant mice, and tamoxifen was used for treatment. In addition, BMPR2 mutant mice were crossed onto oestrogen receptor (ESR)1 and ESR2 knockout backgrounds to assess receptor specificity. Haemodynamic and metabolic outcomes were measured.Oestrogen inhibition both prevented and treated PAH in BMPR2 mutant mice. This was associated with reduction in metabolic defects including oxidised lipid formation, insulin resistance and rescue of peroxisome proliferator-activated receptor-γ and CD36. The effect was mediated primarily through ESR2, but partially through ESR1.Our data suggest that trials of oestrogen inhibition in human PAH are warranted, and may improve pulmonary vascular disease through amelioration of metabolic defects. Although fulvestrant and anastrozole were more effective than tamoxifen, tamoxifen may be useful in premenopausal females, because of a reduced risk of induction of menopause.
Copyright ©ERS 2017.
PURPOSE - Alpelisib, a selective oral inhibitor of the class I PI3K catalytic subunit p110α, has shown synergistic antitumor activity with endocrine therapy against ER/PIK3CA-mutated breast cancer cells. This phase Ib study evaluated alpelisib plus letrozole's safety, tolerability, and preliminary activity in patients with metastatic ER breast cancer refractory to endocrine therapy.
EXPERIMENTAL DESIGN - Twenty-six patients received letrozole and alpelisib daily. Outcomes were assessed by standard solid-tumor phase I methods. Tumor blocks were collected for DNA extraction and next-generation sequencing.
RESULTS - Alpelisib's maximum-tolerated dose (MTD) in combination with letrozole was 300 mg/d. Common drug-related adverse events included hyperglycemia, nausea, fatigue, diarrhea, and rash with dose-limiting toxicity occurring at 350 mg/d of alpelisib. The clinical benefit rate (lack of progression ≥6 months) was 35% (44% in patients with PIK3CA-mutated and 20% in PIK3CA wild-type tumors; 95% CI, 17%-56%), including five objective responses. Of eight patients remaining on treatment ≥12 months, six had tumors with a PIK3CA mutation. Among evaluable tumors, those with FGFR1/2 amplification and KRAS and TP53 mutations did not derive clinical benefit. Overexpression of FGFR1 in ER/PIK3CA mutant breast cancer cells attenuated the response to alpelisib in vitro CONCLUSIONS: The combination of letrozole and alpelisib was safe, with reversible toxicities. Clinical activity was observed independently of PIK3CA mutation status, although clinical benefit was seen in a higher proportion of patients with PIK3CA-mutated tumors. Phase II and III trials of alpelisib and endocrine therapy in patients with ER breast cancer are ongoing. Clin Cancer Res; 23(1); 26-34. ©2016 AACR.
©2016 American Association for Cancer Research.
PURPOSE - Enzalutamide, a potent oral androgen receptor inhibitor, improves survival in men with metastatic castration-resistant prostate cancer (CRPC) before and after chemotherapy. Bicalutamide, a nonsteroidal antiandrogen, is widely used to treat men with nonmetastatic or metastatic CRPC. The efficacy and safety of these drugs were compared in this randomized, double-blind, phase II study of men with CRPC.
PATIENTS AND METHODS - A total of 396 men with nonmetastatic (n = 139) or metastatic (n = 257) CRPC were randomly assigned to enzalutamide 160 mg per day (n = 198) or bicalutamide 50 mg per day (n = 198). Androgen deprivation therapy was continued in both arms. The primary end point was progression-free survival (PFS).
RESULTS - Enzalutamide reduced the risk of progression or death by 76% compared with bicalutamide (hazard ratio [HR], 0.24; 95% CI, 0.18 to 0.32; P < .001). Median PFS was 19.4 months with enzalutamide versus 5.7 months with bicalutamide. Enzalutamide resulted in significant improvements in all key secondary end points: time to prostate-specific antigen progression (HR, 0.19; 95% CI, 0.14 to 0.26; P < .001); proportion of patients with a ≥ 50% prostate-specific antigen response (81% v 31%; P < .001); and radiographic PFS in metastatic patients (HR, 0.32; 95% CI, 0.21 to 0.50; P < .001). Beneficial effects with enzalutamide were observed in both nonmetastatic and metastatic subgroups. The observed adverse event profile was consistent with that from phase III enzalutamide trials.
CONCLUSION - Enzalutamide significantly reduced risk of prostate cancer progression or death compared with bicalutamide in patients with nonmetastatic or metastatic CRPC.
© 2016 by American Society of Clinical Oncology.
For most patients with chronic myeloid leukemia, tyrosine kinase inhibitors (TKIs) have turned a fatal disease into a manageable chronic condition. Imatinib, the first BCR-ABL1 TKI granted regulatory approval, has been surpassed in terms of molecular responses by the second-generation TKIs nilotinib, dasatinib, and bosutinib. Recently, ponatinib was approved as the only TKI with activity against the T315I mutation. Although all TKIs are associated with nonhematologic adverse events (AEs), experience with imatinib suggested that toxicities are typically manageable and apparent early during drug development. Recent reports of cardiovascular AEs with nilotinib and particularly ponatinib and of pulmonary arterial hypertension with dasatinib have raised concerns about long-term sequelae of drugs that may be administered for decades. Here, we review what is currently known about the cardiovascular toxicities of BCR-ABL1 TKIs, discuss potential mechanisms underlying cardiovascular AEs, and elucidate discrepancies between the reporting of such AEs between oncology and cardiovascular trials. Whenever possible, we provide practical recommendations, but we concede that cause-directed interventions will require better mechanistic understanding. We suggest that chronic myeloid leukemia heralds a fundamental shift in oncology toward effective but mostly noncurative long-term therapies. Realizing the full potential of these treatments will require a proactive rational approach to minimize long-term cardiovascular and cardiometabolic toxicities.
© 2015 by American Society of Clinical Oncology.
BACKGROUND - Androgen deprivation therapy (ADT) is a standard treatment for patients with aggressive prostate cancer. Although ADT improves survival, it increases the risk of diabetes. Emerging evidence suggests that ADT increases adverse cardiovascular events as early as 3 months after initiation in patients with cardiovascular disease, but the mechanism is unknown. We hypothesized that ADT may impair endothelium-dependent vasodilation due to increases in lipids and insulin resistance and may provide a link for heightened cardiovascular risk in this population.
METHODS AND RESULTS - We prospectively evaluated conduit artery endothelium-dependent and -independent vasodilation, lipids, and insulin resistance in 16 consecutively treated men (mean age 66 ± 7 years; 25% with diabetes) with prostate cancer before and after 3 months of ADT. High-resolution B-mode ultrasound was used to assess flow-mediated (endothelium-dependent) and nitroglycerine-mediated (endothelium-independent) brachial artery vasodilation. ADT significantly increased insulin resistance, total cholesterol, HDL, and LDL. Endothelium-dependent vasodilation was greater at 3 months than at baseline (10.8% [interquartile range: 7.7% to 14.6%] versus 8.9% [interquartile range: 4.0% to 12.6%], respectively; P=0.046, allometric P=0.037). Nitroglycerine-mediated vasodilation did not change from baseline (P>0.2). The subset of participants on ADT for 6 months returned for reevaluation at 1 year. In this group, endothelium-dependent vasodilation increased from baseline to 3 months and returned to baseline 6 months after ADT withdrawal (9.4% [interquartile range: 6.9% to 10.9%], 11.6% [interquartile range: 7.9% to 15.2%], and 9.0% [interquartile range: 5.1% to 12.5%], respectively; P=0.05).
CONCLUSIONS - In contrast to our expectation, ADT improved endothelium-dependent vasodilation and its cessation returned endothelium-dependent vasodilation to baseline. Determining the mechanism of this change requires further investigation.
© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.
Androgen receptor splicing variants (ARVs) that lack the ligand-binding domain (LBD) are associated with the development of castration-resistant prostate cancer (CRPC), including resistance to the new generation of high-affinity anti-androgens. However, the mechanism by which ARV expression is regulated is not fully understood. In this study, we show that the activation of classical nuclear factor-kappa B (NF-κB) signaling increases the expression of ARVs in prostate cancer (PCa) cells and converts androgen-sensitive PCa cells to become androgen-insensitive, whereas downregulation of NF-κB signaling inhibits ARV expression and restores responsiveness of CRPC to anti-androgen therapy. In addition, we demonstrated that combination of anti-androgen with NF-κB-targeted therapy inhibits efficiently tumor growth of human CRPC xenografts. These results indicate that induction of ARVs by activated NF-κB signaling in PCa cells is a critical mechanism by which the PCa progresses to CRPC. This has important implications as it can prolong the survival of CRPC patients by restoring the tumors to once again respond to conventional androgen-deprivation therapy (ADT).
UNLABELLED - (18)F-3-fluoro-5-[(pyridin-3-yl)ethynyl]benzonitrile ((18)F-FPEB) is a potent and specific radioligand for the metabotropic glutamate receptor subtype 5 (mGluR5). Before undertaking clinical research studies with (18)F-FPEB, we performed studies of human radiation dosimetry.
METHODS - Serial whole-body scans were obtained in 9 healthy human subjects (5 men, 4 women) for 190-440 min after the intravenous administration of (18)F-FPEB. Radiation doses were estimated using the OLINDA/EXM software.
RESULTS - Peak organ doses were to the urinary bladder wall, 0.258 mGy/MBq (0.955 rad/mCi), and gallbladder wall, 0.193 mGy/MBq (0.716 rad/mCi). The effective dose was 0.025 mSv/MBq (0.0922 rem/mCi). The doses to the red marrow and spleen were 0.00797 mGy/MBq (0.0295 rad/mCi) and 0.00709 mGy/MBq (0.0262 rad/mCi), respectively. Reducing the urinary voiding interval to 60 or 90 min lowered the urinary bladder wall dose to 0.0885 mGy/MBq (0.327 rad/mCi) or 0.128 mGy/MBq (0.473 rad/mCi), respectively, and the effective dose to 0.0149 mSv/MBq (0.0551 rem/mCi) or 0.0171 mSv/MBq (0.0634 rem/mCi), respectively.
CONCLUSION - Urinary voiding should be performed during (18)F-FPEB studies to minimize radiation exposure to research subjects.
© 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
The plasma-membrane integrin αIIbβ3 (CD41/CD61, GPIIbIIIa) is a major functional receptor in platelets during clotting. A common isoform of integrin β3, Leu33Pro is associated with enhanced platelet function and increased risk for coronary thrombosis and stroke, although these findings remain controversial. To better understand the molecular mechanisms by which this sequence variation modifies platelet function, we produced transgenic knockin mice expressing a Pro32Pro33 integrin β3. Consistent with reports utilizing human platelets, we found significantly reduced bleeding and clotting times, as well as increased in vivo thrombosis, in Pro32Pro33 homozygous mice. These alterations paralleled increases in platelet attachment and spreading onto fibrinogen resulting from enhanced integrin αIIbβ3 function. Activation with protease-activated receptor 4- activating peptide, the main thrombin signaling receptor in mice, showed no significant difference in activation of Pro32Pro33 mice as compared with controls, suggesting that inside-out signaling remains intact. However, under unstimulated conditions, the Pro32Pro33 mutation led to elevated Src phosphorylation, facilitated by increased talin interactions with the β3 cytoplasmic domain, indicating that the αIIbβ3 intracellular domains are primed for activation while the ligand-binding domain remains unchanged. Acute dosing of animals with a Src inhibitor was sufficient to rescue the clotting phenotype in knockin mice to wild-type levels. Together, our data establish that the Pro32Pro33 structural alteration modifies the function of integrin αIIbβ3, priming the integrin for outside-in signaling, ultimately leading to hypercoagulability. Furthermore, our data may support a novel approach to antiplatelet therapy by Src inhibition where hemostasis is maintained while reducing risk for cardiovascular disease.
PURPOSE - Buparlisib, an oral reversible inhibitor of all class I phosphoinositide-3-kinases, has shown antitumoral activity against estrogen receptor (ER)-positive breast cancer cell lines and xenografts, alone and with endocrine therapy. This phase Ib study evaluated buparlisib plus letrozole's safety, tolerability, and preliminary activity in patients with metastatic ER-positive breast cancer refractory to endocrine therapy.
PATIENTS AND METHODS - Patients received letrozole and buparlisib in two different administration schedules. Outcomes were assessed by standard solid-tumor phase I methods. [(18)F]fluorodeoxyglucose-positron emission tomography/computed tomography ([(18)F]FDG-PET/CT) scans were done at baseline and 2 weeks after treatment initiation. Tumor blocks were collected for phosphoinositide-3-kinase pathway mutation analysis.
RESULTS - Fifty-one patients were allocated sequentially to continuous or intermittent (five on/two off days) buparlisib administration on an every-4-week schedule. Buparlisib's maximum-tolerated dose (MTD) was 100 mg/d. Common drug-related adverse events included ≤ grade 2 hyperglycemia, nausea, fatigue, transaminitis, and mood disorders. The clinical benefit rate (lack of progression ≥ 6 months) among all patients treated at the MTD was 31%, including two objective responses in the continuous dose arm. Of seven patients remaining on treatment ≥ 12 months, three had tumors with PIK3CA hot-spot mutation. Patients exhibiting metabolic disease progression by [(18)F]FDG-PET/CT scan at 2 weeks progressed rapidly on therapy.
CONCLUSION - The letrozole and buparlisib combination was safe, with reversible toxicities regardless of schedule administration. Clinical activity was observed independent of PIK3CA mutation status. No metabolic response by [(18)F]FDG-PET/CT scan at 2 weeks was associated with rapid disease progression. Phase III trials of buparlisib and endocrine therapy in patients with ER-positive breast cancer are ongoing.