[High level systolic blood pressure trajectories is the risk factor for cancer]

Objective: To explore the effect of systolic blood pressure (SBP) trajectories on cancers. Methods: The relevant data of 54, 888 employees of Kailuan (Group) Limited Liability Company who participated in the 3 health examinations from 2006-2007, 2008-2009, 2010-2011 were collected and the new onset cancer cases were recorded. The systolic blood pressure trajectory grouping was carried out using the blood pressure measurement values of the 3 physical examinations. The life table method was used to calculate the incidence of cancer, and the multivariate Cox proportional hazard regression model was used to analyze the influence factors of cancer. Results: According to the systolic blood pressure trajectory, 54, 888 subjects were divided into 5 groups, including 14, 326 in the low-stable group, 25, 630 in the moderate-stable group, 5, 390 in the moderate-increasing group, 6, 438 in the elevated-lowering group, and 3, 104 in the elevated-stable group. A total of 1, 070 new onset cancer occurred during the follow-up period of (4.95±0.53) years. The incidence of cancer in the low-stable group, moderate-stable group, moderate-increasing group, elevated-lowering group and elevated-stable group were 1.3% (177/14, 326), 2.2% (491/25, 360), 3.1% (147/5, 390), 2.7% (156/6, 438) and 3.8% (99/3, 104), respectively, the difference was statistically significant (P<0.001). After adjusting for gender, age, smoking, drinking, physical exercise, body mass index (BMI), fasting blood glucose, total cholesterol, antihypertensive drugs, hypoglycemic drugs, and lipid-lowering drugs, multivariate Cox regression analysis showed that the systolic blood pressure trajectory was related to the incidence of cancer. Compared with the low-stable group, the Hazard ratio (HR) in the moderate-stable group, moderate-increasing group, elevated-lowering group and elevated-stable group were 1.413, 1.731, 1.557 and 1.907, respectively (all P<0.001). Conclusion: High systolic blood pressure trajectories is the risk factor for cancer.

[Association between sleep duration and brachial-ankle pulse wave velocity]

Objective: To investigate the association between sleep duration and brachial-ankle pulse wave velocity (baPWV). Methods: A cross-sectional study method was used to observe 38 604 employees of Kailuan Group who participated in the physical examination and the baPWV test from January 2010 to July 2018. The age was (51.6±11.1) years old. There were 72.4% (27 955/38 604) male participants. According to the sleep duration, subjects were divided into 5 groups including ≤ 5 hours group (3 762 cases),>5 hours and ≤6 hours group (9 585 cases),>6 hours and ≤7 hours group (12 604 cases), >7 hours and ≤8 hours group (11 921 cases) and >8 hours group (732 cases). Multivariate logistic regression model was used to analyze the association between sleep duration and the baPWV. Results: The age was (51.6±11.1) years old. There were 72.4% (27 955/38 604) male participants. The prevalence of baPWV≥14 m/s in ≤ 5 hours group, >5 hours and ≤6 hours group, >6 hours and ≤7 hours group, >7 hours and ≤8 hours group, and >8 hours group was 63.5% (2 389/3 762), 58.9% (5 645/9 585), 55.0% (6 926/12 604), 53.3% (6 356/11 921) and 54.8% (401/732) respectively. After adjusting for confounding factors including age, gender, smoking, drinking, physical exercise, snoring, hypertension, diabetes mellitus, dyslipidemia, body mass index≥24 kg/m(2), mean arterial pressure, heart rate, and C-reactive protein, the multivariate logistic regression analysis showed that the OR were 1.48 (95%CI 1.29-1.70, P<0.01) and 1.18 (95%CI 1.07-1.30, P<0.01) respectively for baPWV≥14 m/s in ≤ 5 hours and >5 hours and ≤6 hours group when compared with >7 hours and ≤ 8 hours group. Conclusion: Short sleep duration is associated with elevated baPWV in mid-aged Chinese population.

Abstract P6-05-01: A novel cleaved cytoplasmic lncRNA LacRNA interacts with PHB2 and suppresses breast cancer metastasis via repressing MYC targets

Long noncoding RNAs (lncRNAs) have been implicated in breast cancer metastases through largely unknown mechanisms. In this study, we used microarray analysis to compare lncRNAs expression levels between matched pairs of breast lymph node metastatic tissues and primary tumors. We discovered that lncRNA LINC00478 was substantially downregulated in the metastatic tumor samples. Interestingly, we found that LINC00478 could be cleaved by RNase to simultaneously generates the mature 5' ends of cytoplasmic RNA and 3' ends of nuclear RNA by polyadenylation. We named 5' ends 791-nt RNA as LacRNA (LINC00478-assciated cytoplasmic RNA). Over expression of full-length LINC00478 and LacRNA, but not LINC00478 3' RNA, significantly inhibited breast cancer proliferation, invasion and metastasis in vitro and in vivo.We used CRISPR-dCas9 complex to mediate efficient transcriptional activation of LacRNA at endogenous genomic loci followed by RNA-seq analyses. Gene set enrichment analysis (GSEA) showed that the MYC pathway/targets were prominent gene sets negatively enriched in LacRNA-activated cells. Further study revealed that LacRNA exerted its tumor suppressive activity by directly binding with prohibitin2(PHB2) to enhance its protein stability, which promoted PHB2 competing with MYC for transcriptionally suppressing the MYC target genes (e.g., CDC20, CDC45, CCNA2 and MAD2L1). Mechanistically, LacRNA inhibits breast cancer invasion and metastasis by interacting with PHB2 through LacRNA's 1-300nt region. In addition, taking advantage of CRISPR system to knock-out and activate the expression of LacRNA, as well as rescue experiment, we uncovered the positive correlation between LacRNA and PHB2 and their role in suppressing MYC target genes and cancer metastasis. At the same time, LacRNA can attenuated the MYC induced activation of MYC targets through binding with PHB2, indicating that LacRNA plays a central role in the suppression of MYC target genes. We further explored the role of LacRNA in inhibiting lung metastasis by implanting LacRNA-activated LM2 cells into the mammary fat pads of NOD-SCID mice. Luciferase imaging and histological analysis were used to detect lung metastasis and found that LacRNA significantly suppressed lung metastasis. Immunohistochemistry were used to detect the expression of PHB2 and MYC targets in both orthotopic tumors and lung metastasis and verified their correlation in vivo. Extensive analyses of clinical data indicated that LacRNA level was substantially downregulated in metastases tumors accompanied by enrichment of MYC targets. The robustness value of LacRNA expression was further verified in two independent patient cohorts, including 530 invasive breast cancer tumors in Fudan University Shanghai Cancer Center (FUSCC) and 819 breast patients' data from TCGA. High LacRNA expression level had a significantly better clinical outcome in both cohorts and represented an independent prognostic predictor for DFS (HR=0.48, P=0.006, multivariate analysis) and OS (HR=0.32, P=0.009, multivariate analysis) in FUSCC cohort. Collectively, LacRNA functions as a tumor suppressor lncRNA that inhibits breast cancer invasion-metastasis cascade.

Citation Format: Guo R, Su Y-H, Xue J-y, Si J, Chi Y-y, Wu J. A novel cleaved cytoplasmic lncRNA LacRNA interacts with PHB2 and suppresses breast cancer metastasis via repressing MYC targets [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-05-01.

Electron microscopy of viral RNA: molecular weight determination of bacterial and animal virus RNAs

A method for preparation of single-stranded RNA for electron microscopy determination of molecular weight is reported. The method uses treatment with formaldehyde at elevated temperatures to remove secondary structure and spreading in a protein monolayer from 50% formamide onto a 50% formamide hypophase. Molecular weights were determined for some bacterial and animal viruses, for which conflicting values had been reported earlier. Molecular weights determined by the method, using Escherichia coli large subunit rRNA for a standard (1.1 x 10(6)), are as follows: E. coli small subunit rRNA, 0.53 x 10(6); coliphage f2-RNA, 1.3 x 10(6); Qbeta-RNA, 1.55 x 10(6); and Newcastle disease virus RNA, 5.78 x 10(6).