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.

[Acting mechanisms and research methods of long noncoding RNAs].

Long non-coding RNAs (lncRNAs) play biological roles through a variety of mechanisms, including genetic imprinting, chromatin remodeling, cell cycle control, splicing regulation, mRNA decay, and translational regulation. LncRNAs are involved in the regulation of gene expression through the above mechanisms in different levels. Establishment and application of research technologies are important in understanding of lncRNAs functions. Microarray, RNA sequencing, Northern blot, real time quantitative reverse transcription-polymerase chain reaction, fluorescence in situ hybridization, RNA interference, and RNA-binding protein immunoprecipitation are major tools of exploring biological functions of lncRNAs. Here, we highlighted three advanced methods, i.e., fast predictions of RNA and protein interactions and domains (catRAPID), chromatin isolation by RNA purification (ChIRP), and combined knockdown and localization analysis of non-coding RNAs (c-KLAN).

Growth inhibitory effect of 4-phenyl butyric acid on human gastric cancer cells is associated with cell cycle arrest.

AIM: To investigate the growth effects of 4-phenyl butyric acid (PBA) on human gastric carcinoma cells and their mechanisms. METHODS: Moderately-differentiated human gastric carcinoma SGC-7901 and lowly-differentiated MGC-803 cells were treated with 5, 10, 20, 40, and 60 µmol/L PBA for 1-4 d. Cell proliferation was detected using the MTT colorimetric assay. Cell cycle distributions were examined using flow cytometry. RESULTS: The proliferation of gastric carcinoma cells was inhibited by PBA in a dose- and time-dependent fashion. Flow cytometry showed that SGC-7901 cells treated with low concentrations of PBA were arrested at the G0/G1 phase, whereas cells treated with high concentrations of PBA were arrested at the G2/M phase. Although MGC-803 cells treated with low concentrations of PBA were also arrested at the G0/ G1 phase, cells treated with high concentrations of PBA were arrested at the S phase. CONCLUSION: The growth inhibitory effect of PBA on gastric cancer cells is associated with alteration of the cell cycle. For moderately-differentiated gastric cancer cells, the cell cycle was arrested at the G0 /G1 and G2/M phases. For lowly-differentiated gastric cancer cells, the cell cycle was arrested at the G0/G1 and S phases.

piRNA, the new non-coding RNA, is aberrantly expressed in human cancer cells.

BACKGROUND: Piwi-interacting RNAs (piRNAs) are a novel class of non-coding single strand RNAs. They are involved in germline development, in silencing of selfish DNA elements, and in maintaining germline DNA integrity. The relationship between piRNAs and carcinogenesis has not been shown yet. METHODS: The relationship between piRNAs and carcinogenesis was identified by microarray screening and real-time quantitative reverse transcription-polymerase chain reaction technology. The piR-651 inhibitor was transfected into gastric cancer cells to assess its influence on cell growth. Cell cycle analysis was used to reveal the cellular mechanisms of piR-651 in the genesis of gastric cancer. RESULTS: piR-651 expression was upregulated in gastric cancer tissues compared with paired non-cancerous tissues. The levels of piR-651 were associated with TNM stage (P=0.032). The expression of piR-651 in gastric, colon, lung, and breast cancer tissues was higher than that in paired non-cancerous tissues. The upregulated expression of piR-651 was confirmed in several cancer cell lines including gastric, lung, mesothelium, breast, liver, and cervical cancer cell lines. The growth of gastric cancer cells was inhibited by a piR-651 inhibitor and arrested at the G(2)/M phase. CONCLUSION: piR-651 might be involved in the development of gastric cancer and other cancers, and is a potential marker for cancer diagnosis.

Telmisartan attenuates aortic hypertrophy in hypertensive rats by the modulation of ACE2 and profilin-1 expression.

Profilin-1 has recently been linked to vascular hypertrophy and remodeling. Here, we assessed the hypothesis that angiotensin (Ang) II type I receptor antagonist telmisartan improves vascular hypertrophy by modulation of expression of profilin-1 and angiotensin-converting enzyme 2 (ACE2). Ten-week-old male spontaneously hypertensive rats (SHR) were received oral administration of telmisartan (5 or 10mg/kg; daily) or saline for 10 weeks. Compared with Wistar-Kyoto (WKY) rats, there were marked increases in systolic blood pressure and profilin-1 expression and reduced ACE2 and peroxisome proliferator activated receptor-γ (PPARγ) levels in aorta of SHR, associated with elevated extracellular-signal regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK) phosphorylation signaling and aortic hypertrophy characterized with increased media thickness, which were strikingly reversed by telmisartan. In cultured human umbilical artery smooth muscle cells (HUASMCs), Ang II induced a dose-dependent increase in profilin-1 expression, along with decreased ACE2 protein expression and elevated ERK1/2 and JNK phosphorylation. In addition, blockade of ERK1/2 or JNK by either specific inhibitor was able to abolish Ang II-induced ACE2 downregulation and profilin-1 upregulation in HUASMCs. Importantly, treatment with telmisartan (1 or 10 µM) or recombinant human ACE2 (2mg/ml) largely ameliorated Ang II-induced profilin-1 expression and ERK1/2 and JNK phosphorylation and augmented PPARγ expression in the cultured HUASMCs. In conclusion, telmisartan treatment attenuates vascular hypertrophy in SHR by the modulation of ACE2 and profilin-1 expression with a marked reversal of ERK1/2 and JNK phosphorylation signaling pathways.

[Effect of microRNA on proliferation of human tongue carcinoma Tca8113 cells].

OBJECTIVE: To investigate the effects of microRNA (miRNA) on proliferation of cultured human squamous cell carcinoma of tongue Tca8113 cells. METHODS: The mimics or inhibitors of miRNA-31 or miRNA-139 were transfected into Tca8113 cells using liposome. Tca8113 cell proliferation was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. RESULTS: The absorbance (A) values of control group at 24 h, 48 h and 72 h were 0.125 +/- 0.002, 0.169 +/- 0.002 and 0.216 +/- 0.004, respectively. The mimics of miRNA-31 increased Tca8113 cell proliferation, with A values increasing to 0.136 +/- 0.001 (P < 0.001), 0.186 +/- 0.004 (P < 0.001) and 0.249 +/- 0.012 (P < 0.01), respectively. The inhibitors of miRNA-139 also increased A values to 0.148 +/- 0.002 (P < 0.001), 0.214 +/- 0.002 (P < 0.001) and 0.250 +/- 0.009 (P < 0.01), respectively. Contrast with these results, the inhibitors of miRNA-31 decreased Tca8113 cell proliferation, with A values decreasing to 0.145 +/- 0.001 and 0.155 +/- 0.011 (both of P < 0.001) at 48 h and 72 h, respectively. The mimics of miRNA-139 also decreased A to 0.135 +/- 0.001 and 0.170 +/- 0.009 (both of P < 0.001). CONCLUSIONS: miRNA-31 and miRNA-139 play an important role in the carcinogenesis of human tongue carcinomas. It may become a new method for the treatment of tongue carcinomas by adjustment the activities of miRNA.

Detection of circulating tumor cells in peripheral blood from patients with gastric cancer using microRNA as a marker.

Recently, the detection of occult cancer cells in peripheral blood has received a great deal of attention regarding the prediction of postoperative cancer recurrence and for novel strategies of adjuvant therapy. The aim of this study was to establish a new molecular diagnostic method of detecting circulating tumor cells. Gastric cancer SGC-7901 cells in 2 ml blood from healthy volunteers were serially diluted. Additional peripheral blood samples were collected from 90 patients and 27 healthy volunteers. Real-time reverse transcription-polymerase chain reaction was used to detect the levels of microRNA-106a (miR-106a) and microRNA-17 (miR-17). Receiver operating characteristics (ROC) curves were constructed. In recovery experiments, a significant correlation between the number of cancer cells and the levels of both miR-106a (r = -0.906, p = 0.037) and miR-17 (r = -0.912, p = 0.031) was found. In preoperative and postoperative patient groups, miR-106a and miR-17 levels were significantly higher than those in controls. The areas under the ROC curve for miR-106a, miR-17, and combination were 0.684 (p = 0.0066), 0.743 (p = 0.0001), and 0.741 (p = 0.0002), respectively. Our results indicate that the detection of miRNA in peripheral blood may be a novel tool for monitoring circulating tumor cells in patients with gastric cancers.

[The anti-proliferation and anti-migration dual effects of aloe-emodin on KB cells and its mechanism].

OBJECTIVE: To investigate the anti-proliferation and anti-migration dual effects of aloe-emodin on KB cells and its mechanisms. METHODS: KB cells were treated with 2.5, 5, 10, 20 and 40 micromol/L aloe-emodin. Crystal violet assay was used to determine the long-term growth inhibition of aloe-emodin on human oral cancer KB cells. Scratch wound-healing motility assay was used to measure the antimigration effect The protein kinase C alpha and c-myc expression changes in protein levels were detected by Western blotting. RESULTS: A durable cell growth inhibitory effect of aloe-emodin on KB cells was found. Treatment of aloe-emodin resulted in the inhibition of cell migration. The protein kinase C alpha and c-myc in protein levels were decreased upon treatment with aloe-emodin compared with controls. CONCLUSIONS: The anti-proliferation and anti-migration effects of aloe-emodin on KB cells are associated with the suppression of protein kinase C pathway.

Anticancer effect of aloe-emodin on cervical cancer cells involves G2/M arrest and induction of differentiation.

AIM: The aim of this study was to investigate the effects of aloe-emodin, a natural compound from the root and rhizome of Rheum palmatum, on the growth of human cervical cancer cells, HeLa. METHODS: HeLa cells were treated with various concentrations of aloe-emodin for 1-5 d, and cell growth was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay. The long-term growth effect was investigated by crystal violet assay. The distributions of the cell cycle and apoptosis were analyzed by flow cytometry. The alkaline phosphatase (ALP) activity was analyzed by a chemical analyzer. Finally, Western blotting was used to indicate the abundant changes of protein kinase C (PKC), c-myc, cyclins, cyclin-dependent kinases (CDK), and proliferating cell nuclear antigen (PCNA). RESULTS: Aloe-emodin inhibited the growth of HeLa cells in a dose-dependent manner at concentrations ranging between 2.5 and 40 micromol/L. The flow cytometric analysis showed that HeLa cells were arrested at the G2/M phase. This effect was associated with the decrease in cyclin A and CDK2, and the increase in cyclin B1 and CDK1. More importantly, the ALP activity was found to be increased by aloe-emodin treatment, and accompanied by the inhibition of PCNA expression. In addition, aloe-emodin suppressed the expression of PKCalpha and c-myc. CONCLUSION: These findings provide a possible mechanistic explanation for the growth inhibitory effect of aloe-emodin on HeLa, which includes cell cycle arrest and inducing differentiation.

Detecting AFP mRNA in peripheral blood of the patients with hepatocellular carcinoma, liver cirrhosis and hepatitis.

BACKGROUND: The low frequency of disseminated carcinoma cells in the blood now makes immunomagnetic bead sorting and reverse transcriptase-polymerase chain reaction (RT-PCR) technique more popular. METHODS: Three milliliters of peripheral blood were collected from 91 patients and 18 normal donors. The circulating carcinoma cells were enriched with CD45 and Ber-EP4 immunomagnetic beads. The alpha-fetoprotein (AFP) mRNA was amplified with nested RT-PCR. RESULTS: The total positive detection rate was 72.1%, 43.8%, 25.0%, 100%, and 66.7% in patients with hepatocellular carcinoma (HCC) untreated, liver cirrhosis (LC), hepatitis, metastasis liver cancer, and postsurgery of hepatocellular carcinoma, respectively. There was a significant difference among the patients with HCC, LC and hepatitis (HCC vs. LC, P<0.05; HCC vs. hepatitis, P<0.01) and between Class A and B of the HCC patients (P<0.05). Meanwhile, AFP mRNA was markedly expressed in HCC patients compared to the patients with no HCC (LC and hepatitis). The levels of aspartate transaminase (AST) and gamma-glutamyltranspeptidase (GGT) were significantly different in AFP mRNA-positive patients with autoimmune chronic active hepatitis B (CAHB) or LC in contrast to the corresponding negative patients. CONCLUSION: Combining negative and positive immunomagnetic bead sorting and RT-PCR technique can effectively detect circulating tumor cells. AFP mRNA is a more reliable marker of metastasis compared to serum AFP.

[Gene studies and nobel prize].

Gene is a DNA sequence which can be expressed and produces gene products (protein or RNA). By 2003, there are 51 Nobel Prize owners related to gene studies. Among them, 44 persons are in physiology or medicine (account for 24.72% of total 178), 7 persons are in chemistry (account for 5.69% of total 123). The paper reviews them in following 6 aspects: Drosophlie melanogaster is a good material for gene study; the double helix model of DNA structure provides a hard foundation in gene study; the studies on gene regulation illuminate many functions of gene; genetic central dogma researches created 11 Noble Prize laureates; gene engineering technologies make possible to modify and use genes; and the thorough studies of gene characteristic made us easier to understand many life phenomena.

Effects of daidzein on estrogen-receptor-positive and negative pancreatic cancer cells in vitro.

AIM: To study the effects of daidzein on human pancreatic cancer cells in vitro. METHODS: Human estrogen-receptor (ER)-positive pancreatic cancer cells MiaPaCa-2 and ER-negative pancreatic cancer cells PANC-1 were treated by 0.1 micromol/L, 1 micromol/L, 10 microL, 25 microL, 50 microL, 75 microL and 100 microL of daidzein, respectively. Its antiproliferative effect was studied by MTT assay. RESULTS: Daidzein inhibited the growth of MiaPaCa-2 and PANC-1 cells at the concentrations from 0.1 microL to 100 microL. A dose- and time-dependent manner was found. The IC(50) of daidzein on MiaPaCa-2 and PANC-1 cells was 45 microL and 75 micro, respectively. After MiaPaCa-2 cells were treated by daidzein for 3 d and at the concentrations more than IC(50), the inhibitory manner was identical and the inhibition appeared a saturation phenomenon, but the inhibitory manner of daidzein on PANC-1 cells was different from that of MiaPaCa-2 cells. CONCLUSION: Daidzein has antiproliferative effects on human estrogen-receptor-positive and negative pancreatic cancer cells, but their mechanisms may be different.