Human electronegative LDL induces mitochondrial dysfunction and premature senescence of vascular cells in vivo.

Dysregulation of plasma lipids is associated with age-related cardiovascular diseases. L5, the most electronegative subfraction of chromatographically resolved low-density lipoprotein (LDL), induces endothelial dysfunction, whereas the least electronegative subfraction, L1, does not. In this study, we examined the effects of L5 on endothelial senescence and its underlying mechanisms. C57B6/J mice were intravenously injected with L5 or L1 (2 mg kg-1  day-1 ) from human plasma. After 4 weeks, nuclear γH2AX deposition and senescence-associated ß-galactosidase staining indicative of DNA damage and premature senescence, respectively, were increased in the aortic endothelium of L5-treated but not L1-treated mice. Similar to that, in Syrian hamsters with elevated serum L5 levels induced by a high-fat diet, nuclear γH2AX deposition and senescence-associated ß-galactosidase staining were increased in the aortic endothelium. This phenomenon was blocked in the presence of N-acetyl-cysteine (free-radical scavenger) or caffeine (ATM blocker), as well as in lectin-like oxidized LDL receptor-1 (LOX-1) knockout mice. In cultured human aortic endothelial cells, L5 augmented mitochondrial oxygen consumption and mitochondrial free-radical production, which led to ATM activation, nuclear γH2AX deposition, Chk2 phosphorylation, and TP53 stabilization. L5 also decreased human telomerase reverse transcriptase (hTERT) protein levels and activity. Pharmacologic or genetic manipulation of the reactive oxygen species (ROS)/ATM/Chk2/TP53 pathway efficiently blocked L5-induced endothelial senescence. In conclusion, L5 may promote mitochondrial free-radical production and activate the DNA damage response to induce premature vascular endothelial senescence that leads to atherosclerosis. Novel therapeutic strategies that target L5-induced endothelial senescence may be used to prevent and treat atherosclerotic vascular disease.

The effect of renin-angiotensin-system inhibition on survival and recurrence of N3+ breast cancer patients.

PURPOSE: The purpose of this study was to evaluate the association between the rennin-angiotensin system (RAS) inhibition and the risk of breast cancer (BC) recurrence and progression in N3 positive patients. METHODS: The medical records of patients treated for N3 positive BC in Hacettepe Cancer Institute between 2005 and 2012 were evaluated. Angiotensin converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARB) users were defined as patients who took these medications for at least 6 months in no evidence of disease (NED) stage after the initial diagnosis. The primary and secondary outcome was disease-free survival (DFS) and overall survival (OS). Kaplan-Meier and Cox proportional hazard models were used. RESULTS: A total of 218 pathologic N3 BC patients were included. Follow up ranged from 12 to 212 months (median 49.58). Thirty one patients used ACE inhibitors/ARBs. Univariate analysis showed BC recurrence was lower and OS was higher among patients who used ACE inhibitors/ ARBs, however without reaching statistical significance (p=0.38 and p=0.24, respectively). RAS inhibition was associated with reduced risk of pathologic N3 BC recurrence. CONCLUSION: To the best of our knowledge this is the second study showing that the use of ACE inhibitors/ARBs may be effective in N3 BC. Because of the limited therapeutic options in BC, new drugs or new therapeutic modalities should be considered. In the future, studies with long-term follow-up may be helpful for their implication in clinical practice.

Outcomes of locally advanced breast cancer patients with ≥ 10 positive axillary lymph nodes.

Breast cancers with 10 or more positive lymph nodes at the time of diagnosis are staged as pathological N3a (pN3a) and they have poor prognosis. Recent studies showed five-year disease-free survival (DFS) and overall survival (OS) rates of N3a disease as 43-66 and 58-81 %, respectively. We herein present outcomes of our patients with stage pN3a breast cancer. Among 2,578 patients diagnosed with invasive breast carcinoma at Hacettepe University Hospital between 2002 and 2012, 218 patients (8.4 %) had pN3a disease and were included and analyzed retrospectively in this study. Patients with internal mammary, infraclavicular, and supraclavicular node metastasis or distant metastasis at initial diagnosis were excluded. Demographic features, tumor characteristics, treatment regimens, and patient outcomes in terms of DFS and OS were analyzed. Lymph node ratio was defined as the ratio of positive to total removed lymph nodes. The median age was 49. Most common histological subtype was ductal carcinoma (82.1 %). About 82.6 % of patients had stage T2/T3 cancers and 47.7 % (104) had grade III cancers. Estrogen and progesterone receptors were positive in 133 (61 %) and 121 (55.5 %) patients, respectively. HER2 status was known for 213 patients and was positive in 87 (39.9 %) patients. A total of 27 (12.6 %) patients had triple-negative tumors. Lymphovascular invasion, extracapsular extension, and perineural invasion were present in 106 (48.6 %), 105 (48.2 %), 20 (9.2 %) cases, respectively. A total of 18 patients (8.3 %) received neoadjuvant and 200 patients (91.7 %) received adjuvant chemotherapy, mostly with anthracycline- (95 %) and taxane (60 %)-containing regimens. A total of 210 patients (96.3 %) received radiotherapy. Median follow-up was 39.5 months. A total of 96 patients relapsed on follow-up and 64 patients died. Nineteen of the relapses were locoregional and 77 were distant relapses. The 5-year DFS rate was 46.2 % and the OS rate was 69.8 %. In multivariate Cox regression analysis, grade III disease (HR 1.899, 95 % CI 1.196-3.017, P = 0.007), perineural invasion (HR 2.519, 95 % CI 1.341-4.731, P = 0.004), and lymph node ratio (≥ 0.9 vs. <0.9) (HR 2.290, 95 % CI 1.368-3.835, P = 0.002) were significantly associated with DFS, and grade III disease (HR 2.679, 95 % CI 1.500-4.782, P = 0.001) and lymph node ratio (≥ 0.9 vs. <0.9) (HR 2.182, 95 % CI 1.211-3.932, P = 0.009) were significantly associated with OS. Patients with pN3a disease in our cohort have comparable survival rates with other reports in the literature. Within this high risk group of patients, those with grade III disease, perineural invasion, and lymph node ratio ≥ 0.9 seem to confer poorer prognosis.