Circular RNA hsa_circ_0012673 facilitates lung cancer cell proliferation and invasion via miR-320a/LIMK18521 axis

OBJECTIVE

Lung cancer is one of the most malignant tumors with high morbidity and mortality in the world. The incidence and mortality of lung cancer were increased per year in many countries over the past 50 years. The increasing studies had shown that circular RNA (circRNA) was involved in the progression of lung cancer. Therefore, it was significant to seek the molecular mechanism of circ_0012673 in lung cancer.

MATERIALS AND METHODS

Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to estimate the expression levels of circ_0012673, miR-320a and LIM domain kinase 1 (LIMK1) in lung cancer tissues and cells. 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT), flow cytometry and transwell assays were recruited to evaluate proliferation, apoptosis and mobility of lung cancer cells, respectively. The relative protein expression levels of Vimentin, N-cadherin, E-cadherin and LIMK1 were determined with Western blot assay. The relationships among circ_0012673, miR-320a and LIMK1 were analyzed by starBase database, dual-luciferase reporter assay, and Pearson's correlation.

RESULTS

Circ_0012673 was overexpressed in lung cancer tissues and cell lines. Loss-of-functional experiment confirmed that knockdown of circ_0012673 constrained proliferation, motility and Epithelial-Mesenchymal Transition (EMT), but induced apoptosis by targeting miR-320a. Furthermore, LIMK1 was a target of miR-320a in lung cancer cells. Elevated LIMK1 could abolish the overexpression of miR-320a induced effects on lung cancer cells. Mechanistically, circ_0012673 contributed to lung cancer progression through mediating miR-320a /LIMK1 pathway.

CONCLUSIONS

Circ_0012673 was a tumor-promoter in lung cancer via acting as competing endogenous RNA to regulate LIMK1 expression by binding miR-320a.

Molecular cloning and expression analysis of jasmonic acid dependent but salicylic acid independent LeWRKY1

Various plant genes can be activated or inhibited by phytohormones under conditions of biotic and abiotic stress, especially in response to jasmonic acid (JA) and salicylic acid (SA). Interactions between JA and SA may be synergistic or antagonistic, depending on the stress condition. In this study, we cloned a full-length cDNA (LeWRKY1, GenBank accession No. FJ654265) from Lycopersicon esculentum by rapid amplification of cDNA ends. Sequence analysis showed that this gene is a group II WRKY transcription factor. Analysis of LeWRKY1 mRNA expression in various tissues by qRT-PCR showed that the highest and lowest expression occurred in the leaves and stems, respectively. In addition, LeWRKY1 expression was induced by JA and Botrytis cinerea Pers., but not by SA.

Characterising atherothrombosis in Hong Kong: results of the Hong Kong data from a global atherothrombosis epidemiological survey

OBJECTIVES

To describe the characteristics of patients in Hong Kong with or at risk of atherothrombosis, to determine the proportion of symptomatic patients with more than one vascular bed affected, and to assess the relationship between ankle brachial index and disease severity.

DESIGN

Local participation in an international prevalence study.

SETTING

Five centres in Hong Kong.

PARTICIPANTS

A total of 210 subjects were recruited (105 women and 105 men). Patients were divided into the symptomatic group (with current or previous atherothrombotic symptoms, n=101) and at-risk group (with no current or previous symptoms, but aged over 55 years with at least two specified risk factors, n=109).

MAIN OUTCOME MEASURES

Patient characteristics were described, including the number of arterial beds affected, ankle brachial index, presence of risk factors, and medications taken.

RESULTS

Of the symptomatic patients, 30% had more than one arterial bed involved. A total of 55.4% of the symptomatic group and 18.4% of the at-risk group had abnormal ankle brachial index values. Lower ankle brachial indices were associated with a greater number of affected arterial beds. Diabetes mellitus and hypertension were the most prevalent risk factors in the at-risk group. Symptomatic patients were commonly treated with antihypertensive and antiplatelet agents, whereas at-risk patients were mostly treated with antihypertensive and antidiabetic agents. Only 20% of at-risk patients were taking antiplatelet agents.

CONCLUSIONS

Ankle brachial index is a useful tool for predicting those at risk of atherothrombosis. This simple measurement can be used as part of the screening process in the general practice. The role of antiplatelet agents in primary prevention of atherothrombotic events in at-risk patients deserves further attention.

Statistical significance of probabilistic sequence alignment and related local hidden Markov models

The score statistics of probabilistic gapped local alignment of random sequences is investigated both analytically and numerically. The full probabilistic algorithm (e.g., the "local" version of maximum-likelihood or hidden Markov model method) is found to have anomalous statistics. A modified "semi-probabilistic" alignment consisting of a hybrid of Smith-Waterman and probabilistic alignment is then proposed and studied in detail. It is predicted that the score statistics of the hybrid algorithm is of the Gumbel universal form, with the key Gumbel parameter lambda taking on a fixed asymptotic value for a wide variety of scoring systems and parameters. A simple recipe for the computation of the "relative entropy," and from it the finite size correction to lambda, is also given. These predictions compare well with direct numerical simulations for sequences of lengths between 100 and 1,000 examined using various PAM substitution scores and affine gap functions. The sensitivity of the hybrid method in the detection of sequence homology is also studied using correlated sequences generated from toy mutation models. It is found to be comparable to that of the Smith-Waterman alignment and significantly better than the Viterbi version of the probabilistic alignment.

The relationship between microvessel count and the expression of vascular endothelial growth factor, p53, and K-ras in non-small cell lung cancer

Using immunohistochemical staining, we studied the relationship between the microvessel count (MC) and the expression of K-ras, mutant p53 protein, and vascular endothelial growth factor (VEGF) in 61 surgically resected non-small cell lung cancers (NSCLC) (42 squamous cell carcinoma, 14 adenocarcinoma, 2 large cell carcinoma, 2 adenosquamous carcinoma, and 1 mucoepidermoid carcinoma). MC of the tumors with lymph node (LN) metastasis was significantly higher than that of tumors without LN metastasis (66.1+/-23.1 vs. 33.8+/-13.1, p<0.05). VEGF was positive in 54 patients (88.5%). MC was 58.1+/-25.2 (mean+/-S.D.) in a x200 field, and it was significantly higher in VEGF(+) tumors than in VEGF(-) tumors (61.4+/-23.7 vs. 32.9+/-23.8, p<0.05). VEGF expression was higher in K-ras-positive or mutant p53-positive tumors than in negative tumors (p<0.05). MC was significantly higher in K-ras(+) tumors than in K-ras(-) tumors, although it did not differ according to the level of mutant p53 protein expression. Survival did not differ with VEGF, mutant p53, or K-ras expression, or the level of MC. In conclusion, there is a flow of molecular alterations from K-ras and p53, to VEGF expression, leading to angiogenesis and ultimately lymph node metastasis. Correlations between variables in close approximation and the lack of prognostic significance of individual molecular alterations suggest that tumorigenesis and metastasis are multifactorial processes.

Dynamics and critical behavior of the q model

The q model, a random walk model rich in behavior and applications, is investigated. We introduce and motivate the q model via its application proposed by Coppersmith et al. to the flow of stress through granular matter at rest. For a special value of its parameters the q model has a critical point that we analyze. To characterize the critical point we imagine that a uniform load has been applied to the top of the granular medium and we study the evolution with depth of fluctuations in the distribution of load. Close to the critical point explicit calculation reveals that the evolution of load exhibits scaling behavior analogous to thermodynamic critical phenomena. The critical behavior is remarkably tractable: the harvest of analytic results includes scaling functions that describe the evolution of the variance of the load distribution close to the critical point and of the entire load distribution right at the critical point, values of the associated critical exponents, and determination of the upper critical dimension. These results are of intrinsic interest as a tractable example of a random critical point. Of the many applications of the q model, the critical behavior is particularly relevant to network models of river basins, as we briefly discuss. Finally we discuss circumstances under which quantum network models that describe the surface electronic states of a quantum Hall multilayer can be mapped onto the classical q model. For mesoscopic multilayers of finite circumference the mapping fails; instead a mapping to a ferromagnetic supersymmetric spin chain has proved fruitful. We discuss aspects of the superspin mapping and give an elementary derivation of it making use of operator rather than functional methods.

Effect of noise on a quantum bound state

The evolution of a quantum wave function on a lattice with time-dependent random disorder is studied. It is found that the bound state wave function of a quantum system exhibits intrinsic instability with respect to noisy disorder in the statistical sense. Under the general scheme of time coarse graining, we show nonperturbatively that the stationary attractive potential is completely washed out at large time scales by the existence of the noisy disorder to any order of density correlations.

[Estimation of latency period of lung cancer]

A case-control study with time-related factors was conducted to estimate the latency period of lung cancer. This study included 168 incident male cases of lung cancer histologically confirmed and 336 control patients with non-neoplastic diseases. All patients were interviewed in the hospital wards from May 1987 to May 1990. Data concerning smoking, occupation, method of house heating and cooking fuel used from twelve time windows of looking forward and diet were obtained for three periods of time. A synthetical analysis of forward measures and backward measures were applied. By means of calculating accumulated effective exposure score and excess exposure fraction, the latency period of lung cancer was estimated using multivariate model. Latency of lung cancer is 54.48 years for indoor air pollution, and 56.17 years for total smoking. From estimating latency period of lung cancer from multivariate analysis, it was found that the latency of lung cancer could be affected by the effects of other factors. Therefore, measures which prolong latency period may be of use in the prevention of lung cancer.

Diet and cancer of the colon and rectum: a case-control study in China

A case-control study was carried out in Harbin city to assess the role of diet in the aetiology of colorectal cancer. A total of 336 incident cases of histologically confirmed colorectal cancer (111 colon cancer and 225 rectal cancer) and an equal number of controls with other non-neoplastic diseases were interviewed in hospital wards. Data concerning the average frequency of consumption and amount consumed of single food items were obtained by a dietary history questionnaire. Odds ratios and their confidence limits were computed. Multiple regression for risk status was also used. Vegetables, particularly green vegetables, chives and celery, have a strong protective effect against colorectal cancer. Reduced consumption of meat, eggs, bean products and grain was associated with increasing risk for cancer of the rectum. Alcohol intake was found to be an important risk factor for developing colon cancer and male rectal cancer.