A Comparative Study on Two Territorial Fishes: The Influence of Physical Enrichment on Aggressive Behavior.

Intraspecific aggression is detrimental to body/fin damage, physiological stress, and other problems in aquaculture. Environmental enrichment has been proposed to have positive effects on fish aggressive behavior, physiological stress, and fish welfare, but there are mixed results. Here, we examine the impact of physical enrichment levels (i.e., the intensity of physical enrichment) on aggression in black rockfish (Sebastes schlegelii) and fat greenling (Hexagrammos otakii). Generally, with the increase in the enrichment level, the frequency of the aggressive behavior of black rockfish gradually decreased. In contrast, a non-monotonous effect of the enrichment level on aggression was observed for fat greenling, with low and intermediate levels leading to no or more aggression, while a high enrichment level reduced aggression. After three days, the high-level enrichment groups in both rockfish and greenling reached social stability (i.e., a relatively stable social structure indicated by lower aggression), while aggression in the other groups continued increased. These results show the significant regulatory effect of enrichment levels on the aggressive behavior in both black rockfish and fat greenling. This study may promote the development of environmental enrichment measures, and it provides useful information for reducing fish aggression and improving fish welfare in aquaculture.

Circular RNA 0000096 affects cell growth and migration in gastric cancer.

BACKGROUND: Circular RNAs (circRNAs) are a class of non-coding RNAs broadly expressed in cells of various species. Their role in cancers, especially in gastric cancer, is poorly understood. METHODS: Circular RNA 0000096 (hsa_circ_0000096) levels in 101 paired gastric cancer tissues and adjacent non-tumorous tissues from patients with gastric cancer were detected by real-time quantitative reverse transcription-polymerase chain reaction. A receiver operating characteristic curve was generated to evaluate the diagnostic value of hsa_circ_0000096. RNA interference was used to manipulate the expression of hsa_circ_0000096. Its biological effects were evaluated by flow cytometry, real-time cell analysis, a wound scratch assay, western blot analysis and xenograft models. RESULTS: Hsa_circ_0000096 was found to be significantly downregulated in gastric cancer tissues and gastric cancer cell lines compared with paired adjacent non-tumorous tissues and normal gastric epithelial cells (P<0.001). Moreover, knockdown of hsa_circ_0000096 significantly inhibited cell proliferation and migration in vitro and in vivo. The results of both immunohistochemical and western blot analyses showed that the protein levels of cyclin D1, cyclin-dependent kinase 6 (CDK6), matrix metalloproteinase-2 and MMP-9 were significantly reduced in vitro and in vivo. A gastric cancer xenograft nude mouse model indicated that Ki67 and VEGF were reduced in a dose-dependent manner following knockdown of hsa_circ_0000096. However, the expression of E-cadherin increased. CONCLUSIONS: Hsa_circ_0000096 may be used as a potential novel biomarker for gastric cancer. It affects gastric cancer cell growth and migration by regulating cyclin D1, CDK6, MMP-2 and MMP-9.

Sargassum fusiforme polysaccharides inhibit VEGF-A-related angiogenesis and proliferation of lung cancer in vitro and in vivo.

Sargassum fusiforme (Harv.) is a brown alga belonging to the Sargasaceae family. The Sargassum fusiforme polysaccharides (SFPS) have demonstrated good anti-tumor and immunomodulatory activity. However, the underlying mechanisms of its anti-tumorigenesis, especially the anti-angiogenic activity is yet to be established. In the present study, we attempted to determine the effects of SFPS on the human lung adenocarcinoma SPC-A-1 cells and its xenograft model. The results showed that SFPS provides a concentration-dependent inhibition of SPC-A-1 cell proliferation in in vitro and the tumor growth in in vivo studies. Immunohistochemistry studies revealed that the administration of SFPS significantly decreased CD31, VEGF-A expression and the tumor microvessel density (MVD). SFPS also provided a dose-dependent impairment of cell vitality, induction of cell cycle arrest and apoptosis of human umbilical vein endothelial cells (HUVECs). SFPS inhibited the expression of VEGF-A in tumor cells and its receptor VEGFR2 in HUVECs. The HUVEC tube formation assay showed that SFPS could abrogate the tube formation with relatively decreased tubes length of tube-like capillary similar to anti-VEGF antibody, Avastin®. These findings suggested that SFPS could be used as an alternative anticancer drug as they inhibited the angiogenesis and the microvessel formation through disruption of VEGF signals apart from direct tumor cytotoxicity.

Long noncoding RNA FER1L4 suppresses cancer cell growth by acting as a competing endogenous RNA and regulating PTEN expression.

Aberrantly expressed long noncoding RNAs (lncRNAs) are associated with various cancers. However, the roles of lncRNAs in the pathogenesis of most cancers are unclear. Here, we report that the lncRNA FER1L4 (fer-1-like family member 4, pseudogene) acts as a competing endogenous RNA (ceRNA) to regulate the expression of PTEN (a well-known tumor suppressor gene) by taking up miR-106a-5p in gastric cancer. We observed that FER1L4 was downregulated in gastric cancer and that its level corresponded with that of PTEN mRNA. Both FER1L4 and PTEN mRNA were targets of miR-106a-5p. Further experiments demonstrated that FER1L4 downregulation liberates miR-106a-5p and decreases the abundances of PTEN mRNA and protein. More importantly, FER1L4 downregulation accelerated cell proliferation by promoting the G0/G1 to S phase transition. We conclude that one mechanism by which lncRNAs function in in tumorigenesis is as ceRNAs for tumor suppressor mRNAs.

The functional sites of miRNAs and lncRNAs in gastric carcinogenesis.

Gastric cancer is one of the most common malignant diseases and has one of the highest mortality rates worldwide. Its molecular mechanisms are poorly understood. Recently, the functions of non-coding RNAs (ncRNAs) in gastric cancer have attracted wide attention. Although the expression levels of various ncRNAs are different, they may work together in a network and contribute to gastric carcinogenesis by altering the expression of oncogenes or tumor suppressor genes. They affect the cell cycle, apoptosis, motility, invasion, and metastasis. Dysregulated microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), including miR-21, miR-106, H19, and ANRIL, directly or indirectly regulate carcinogenic factors or signaling pathways such as PTEN, CDK, caspase, E-cadherin, Akt, and P53. Greater recognition of the roles of miRNAs and lncRNAs in gastric carcinogenesis can provide new insight into the mechanisms of tumor development and identify targets for anticancer drug development.

Using circular RNA as a novel type of biomarker in the screening of gastric cancer.

BACKGROUND: Circular RNAs (circRNAs), a class of endogenous RNAs, have emerged as an enigmatic class of RNAs. Little is known about their value in the diagnosis of cancers. METHODS: The targeted circRNA of this study was selected using two circRNA databases: CircBase (http://circbase.org/) and circ2Traits (http://gyanxet-beta.com/circdb/). Divergent primers, rather than commonly used convergent primers, for the circRNA were designed. The circRNA levels in 101 paired gastric cancer tissues and adjacent nontumorous tissues from surgical gastric cancer patients and 36 paired plasma samples from preoperative and postoperative gastric cancer patients were analyzed by real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The specificity of the amplified products was measured by melting curve analysis and DNA sequencing. To observe the stability of circRNA, three randomly selected samples of gastric cancer tissues were stored at room temperature, 4°C and -20°C, and then, their circRNA levels were analyzed. To verify the reproducibility of qRT-PCR, circRNA levels were detected in a set of specimens (n=15) in two independent experiments with an interval of one day. Then, the correlation of their Ct values was determined. The relationships between circRNA expression levels and clinicopathological factors of patients with gastric cancer were further analyzed by one-way analysis of variance. A receiver operating characteristic (ROC) curve was established to evaluate the diagnostic value. RESULTS: Hsa_circ_002059, a typical circular RNA, was first found to be significantly downregulated in gastric cancer tissues compared with paired adjacent nontumorous tissues (p<0.001). Its levels in plasma collected from postoperative gastric cancer patients were found significantly different from those from preoperative gastric cancer patients. The area under the ROC curve was 0.73. Importantly, we further found that lower expression levels were significantly correlated with distal metastasis (P=0.036), TNM stage (P=0.042), gender (P=0.002) and age (P=0.022). The stability of circRNAs and the reproducibility of the qRT-PCR method for detecting circRNA levels were determined. CONCLUSION: These results suggested that circRNAs are highly stable in mammalian cells and that one specific circRNA, hsa_circ_002059, may be a potential novel and stable biomarker for the diagnosis of gastric carcinoma.

Low expression of lncRNA-HMlincRNA717 in human gastric cancer and its clinical significances.

Long noncoding RNAs (lncRNAs) have been gradually confirmed to be tumor-associated biological molecules in recent years. However, the clinical significances of most lncRNAs in the screening of gastric cancer are largely unknown. Based on our lncRNA array results, in this study, we explored the potential relationship between HMlincRNA717 expression levels and clinicopathologic factors of gastric cancer. A total of 313 samples were collected from two cancer centers, and then HMlincRNA717 level in human gastric cancer tissues and gastric cell lines was measured by real-time reverse transcription-polymerase chain reaction. Then, HMlincRNA717 levels at multiple stages of gastric tumorigenesis were investigated and the potential association between it levels, and clinicopathological features were analyzed. The expression levels of HMlincRNA717 in five gastric cancer cell lines, AGS, BGC-823, HGC-27, MGC-803, and SGC-7901, were significantly downregulated than those in normal gastric mucosal epithelial cell line GES-1. It was not only downregulated in 62.6 % (67/107) gastric cancer tissues compared with the paired adjacent normal tissues but also in gastric precancerous lesions. More importantly, our results indicated that HMlincRNA717 expression levels were correlated with cancer distal metastasis (P = 0.034), venous invasion (P = 0.029), and nervous invasion (P = 0.024). Our data suggested that lncRNA-HMlincRNA717 may play crucial roles during cancer occurrence and progression and may be a new potential biomarker of early gastric cancer.

Clinical significance of the low expression of FER1L4 in gastric cancer patients.

Long non-coding RNA (lncRNA) is a new class of regulative non-coding RNA, with a length larger than 200 nucleotides. Recent studies found that there are close relations between disregulative lncRNAs and human tumors. However, the clinical significances are largely unknown. In this study, we investigated the lncRNA-Fer-1-like protein 4 (FER1L4) level in gastric cancer tissues and plasma. The FER1L4 level in human tissues and plasma were measured by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Then, the correlations between the tissue or plasma FER1L4 levels and clinicopathological factors were assessed. A receiver operating characteristic (ROC) curve was constructed for differentiating GC patients from controls. Compared to matched adjacent non-tumorous tissues, FER1L4 expression levels in 91.80 % (56/61) of gastric cancer tissues are significantly decreased. The low FER1L4 level were associated with tumor size (p < 0.001), histologic grade (p = 0.001), general classification (p < 0.001), depth of invasion (p < 0.001), lymphatic metastasis (p < 0.001), distant metastasis (p = 0.003), TNM stage (p < 0.001), vessel or nerve invasion (p < 0.001 or p = 0.003), and serum CA72-4 (p < 0.001). The area under the ROC curve (AUC) was up to 0.778 (p < 0.001) and the sensitivity and specificity were 67.2 and 80.3 %, respectively. Also, plasma FER1L4 was detected by qRT-PCR. Our data show that there was no difference of plasma FER1L4 level between healthy person and preoperative gastric cancer patients, with a sharp decline in 63.9 % (53/83) of gastric cancer patients 2 weeks after surgery (p = 0.028). Taken together, FER1L4 might play a crucial role in human gastric cancer and may be a new potential biomarker for clinical prognosis evaluation.

Non-coding RNAs and gastric cancer.

Non-coding RNAs (ncRNAs) play key roles in development, proliferation, differentiation and apoptosis. Altered ncRNA expression is associated with gastric cancer occurrence, invasion, and metastasis. Moreover, aberrant expression of microRNAs (miRNAs) is significantly related to gastric cancer tumor stage, size, differentiation and metastasis. MiRNAs interrupt cellular signaling pathways, inhibit the activity of tumor suppressor genes, and affect the cell cycle in gastric cancer cells. Some miRNAs, including miR-21, miR-106a and miR-421, could be potential markers for the diagnosis of gastric cancer. Long non-coding RNAs (lncRNAs), a new research hotspot among cancer-associated ncRNAs, play important roles in epigenetic, transcriptional and post-transcriptional regulation. Several gastric cancer-associated lncRNAs, such as CCAT1, GACAT1, H19, and SUMO1P3, have been explored. In addition, Piwi-interacting RNAs, another type of small ncRNA that is recognized by gastroenterologists, are involved in gastric carcinogenesis, and piR-651/823 represents an efficient diagnostic biomarker of gastric cancer that can be detected in the blood and gastric juice. Small interfering RNAs also function in post-transcriptional regulation in gastric cancer and might be useful in gastric cancer treatment.