[Retracted] Functional characterization of the nitrogen permease regulator­like­2 candidate tumor suppressor gene in colorectal cancer cell lines.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that certain of the microscopic images shown in Fig. 1C on p. 3489 and the invasion assay images shown in Fig. 5 on p. 3491 were strikingly similar to data appearing in different form in other articles written by different authors at different research institutes. Moreover, unexpected similarities were identified comparing between a pair of the flow cytometric assay data panels in Fig. 4 on p. 3490, considering that these data were intended to show the results from differently performed experiments. Owing to the fact that the contentious data in the above article had already been published, or were already under consideration for publication, prior to its submission to Molecular Medicine Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 12: 3487­3493, 2015; DOI: 10.3892/mmr.2015.3881].

The effect of oil-water partition coefficient on the distribution and cellular uptake of liposome-encapsulated gold nanoparticles.

The shape, size, and surface features of nanoparticles greatly influence the structure and properties of resulting hybrid nanosystems. In this work, gold nanoparticles (GNPs) were modified via S-Au covalent bonding by glycol monomethyl ether thioctate with poly(ethylene glycol) methyl ether of different molecular weights (i.e., 350, 550, and 750Da). These modified GNPs (i.e., GNP350, GNP550, and GNP750) showed different oil-water partition coefficients (Kp), as detected using inductively coupled plasma-atomic emission spectroscopy. The different Kp values of the gold conjugates (i.e., 13.98, 2.11, and 0.036 for GNP350, GNP550, and GNP750, respectively) resulted in different conjugate localization within liposomes, as observed by transmission electron microscopy. In addition, the cellular uptake of hybrid liposomes co-encapsulating gold conjugates and Nile red was evaluated using intracellular fluorescence intensity. The results indicated that precise GNP localization in the hydrophilic or hydrophobic liposome cavity could be achieved by regulating the GNP oil-water partition coefficient via surface modification; such localization could further affect the properties and functions of hybrid liposomes, including their cellular uptake profiles. This study furthers the understanding not only of the interaction between liposomes and inorganic nanoparticles but also of adjusting liposome-gold hybrid nanostructure properties via the surface chemistry of gold materials.

Gold conjugate-based liposomes with hybrid cluster bomb structure for liver cancer therapy.

Hybrid drug delivery system containing both organic and inorganic nanocarriers is expected to achieve its complementary advantages for the aim of improving the performance of antineoplastic drugs in tumor therapy. Here we report the use of liposomes and gold nanoparticles to construct a liposome with a hybrid Cluster Bomb structure and discuss its unique multi-order drug release property for liver tumor treatment. A very simple method is used for the hybrid liposome preparation and involves mixing two solutions containing liposomes loaded with either non-covalent or covalent Paclitaxel (PTX, namely free PTX or PTX-conjugated GNPs, respectively) by different ratio of volume (25:75, 50:50, 25:75, v/v). Various mixed liposomes were tested to determine the optimal conditions for maximum drug delivery. The optimized liposome was then tested using xenograft Heps tumor-bearing mice and showed the best efficacy for chemotherapeutic inhibition of tumor at PTX liposome: PTX-conjugated GNP liposome of 25:75 ratio (v/v). This system allows for simple and easy preparation while providing a more accurate site- and time-release mode for tumor treatment using antitumor drugs.

Functional characterization of the nitrogen permease regulator-like-2 candidate tumor suppressor gene in colorectal cancer cell lines.

The nitrogen permease regulator­like­2 (NPRL2) gene is a candidate tumor suppressor gene, which has been identified in the 3p21.3 human chromosome region. Decreased expression levels of NPRL2 have been observed in colorectal cancer (CRC) tissues, however, the function of NPRL2 in CRC progression remains to be fully elucidated. The present study investigated the biological characteristics of the HCT116 and HT29 CRC cell lines overexpressing exogenous NPRL2. NPRL2 recombinant lentiviral vectors were also constructed and transfected in the present study. Cell growth was determined using a Cell Counting Kit­8 assay and a colony formation assay. The cell cycle and rate of apoptosis were assessed using flow cytometric analysis. Transwell assays were used to evaluate cell invasion. The protein expression of phosphorylated (p)­AKT and caspase 3, B­cell lymphoma 2 (Bcl2) and Bcl­2­associated X protein apoptosis­associated genes, were detected using western blotting. The results revealed that NPRL2 overexpression inhibited cell growth, induced cell cycle G1 phase arrest, promoted apoptosis and inhibited invasion in the two human CRC cell lines. Furthermore, the protein expression levels of p­AKT and Bcl2 were significantly reduced in the NPRL2­transfected HCT116 and HT29 cells, compared with the mock­transfected group and control group, while the protein expression of caspase­3 was increased. Therefore, NPRL2 acted as a functional tumor suppressor in the CRC cell lines.

Simultaneous silencing of ß-catenin and signal transducer and activator of transcription 3 synergistically induces apoptosis and inhibits cell proliferation in HepG2 liver cancer cells.

The tumorigenesis and maintenance of a cancer cells is dependent upon the collaboration of multiple signaling pathways. Signal transducer and activator of transcription 3 (STAT3) and ß-catenin are at the center of multiple cancer-associated signaling pathways; therefore, simultaneously targeting STAT3 and ß-catenin may be a potential cancer treatment, leading to induced lethality of cancer cells. In the present study, HepG2 liver cancer cells were transfected with small interfering RNA (siRNA) against ß-catenin and STAT3 alone or in combination. The cell growth was assessed using an MTT assay and the levels of cell apoptosis were detected using flow cytometry. Protein levels of caspase-3, cleaved caspase-3, poly(ADP-ribose) polymerase (PARP) and cleaved PARP were determined using western blot analysis. Following siRNA transfection, ß-catenin and STAT3 protein levels decreased at 72 h. HepG2 cell growth inhibition and early apoptosis in the ß-catenin and STAT3 siRNA co-transfection group were significantly greater than those in the groups transfected with ß-catenin or STAT3 siRNA alone. Decreased caspase-3 and PARP levels, as well as enhanced cleavage of caspase-3 and PARP were observed in the ß-catenin and STAT3 co-transfection group. Simultaneous silencing of ß-catenin and STAT3 using siRNAs resulted in an enhanced loss of cell viability and induction of apoptosis in HepG2 liver cancer cells, suggesting that these genes are promising targets for the further preclinical and clinical development of anti-cancer therapeutic strategies, which target several cancer signaling pathways simultaneously.

Nitrogen permease regulator-like 2 enhances sensitivity to oxaliplatin in colon cancer cells.

Colorectal cancer (CRC) is the third most common cancer worldwide. Chemotherapeutic compounds used for the treatment of CRC include oxaliplatin (L-OHP). While L-OHP improves CRC survival, certain patients are resistant. The nitrogen permease regulator like-2 (NPRL2) gene is a candidate tumor suppressor gene that resides in a 120-kb homozygous deletion region on chromosome 3p21.3. In the present study, it was demonstrated that NPRL2 overexpression increases the sensitivity of HCT116 cells to L-OHP. The IC50 of L-OHP was decreased in cells transduced with NPRL2 compared with negative control (NC) cells and the effect of NPRL2 on L-OHP sensitivity was time dependent. Following NPRL2 transduction in HCT116 cells, the cell cycle was arrested in the G1 phase and a partial decrease in the S phase population was observed. Flow cytometric analysis revealed that NPRL2 transduction and L-OHP treatment increased apoptosis compared with NC cells. The mechanism through which NPRL2 overexpression enhances L-OHP sensitivity involves downregulation of the functions of the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin network. Furthermore, L-OHP upregulated caspase-3 and caspase-9 to promote apoptosis in NPRL2-overexpressing cells compared with cells that were transduced with NPRL2 or treated with L-OHP and NC cells (P<0.01). NPRL2 overexpression led to the downregulation of CD24, which could significantly reduce tumor invasiveness and decrease the metastatic capacity of HCT116 cells. These mechanisms are likely active in other types of cancer and may be exploited for the development of novel cancer therapies.

Protection of cultured human hepatocytes from hydrogen peroxide­induced apoptosis by relaxin­3.

Previous studies have suggested that hepatocyte apoptosis may be a fundamental underlying mechanism of liver injury and diseases, such as liver fibrosis. Relaxin­3 has been reported to have anti­fibrotic actions in the heart and to attenuate isoproterenol­induced myocardial injury; however, the beneficial role of relaxin­3 on hepatocyte apoptosis remains to be elucidated. The aim of the present study was to explore the role and possible mechanisms of relaxin­3 through hydrogen peroxide (H2O2)­induced apoptosis in primary human hepatocytes. Cells were treated with relaxin­3 and then cell viability, morphological features, the presence of cleaved caspases as well as the levels of endoplasmic reticulum stress (ERS) protein markers and autophagy markers were evaluated. The H2O2 group showed significantly decreased cell viability, increased apoptosis as well as upregulation of caspases (cleaved caspase­3, ­8 and ­9) and ERS protein markers compared with those of the control group. However, cells treated with relaxin­3 (10 ng/ml) demonstrated improved cell viability, reduced apoptosis and decreased expression of cleaved caspases and ERS markers. However, the expression of autophagy markers remained unchanged following H2O2­induced apoptosis and relaxin­3 treatment. In conclusion, relaxin­3 was shown to protect hepatocytes from H2O2­induced apoptosis via downregulation of cleaved caspase­8 and ­9, as well as inhibition of the ERS pathway.

Functional mechanism of the enhancement of 5-fluorouracil sensitivity by TUSC4 in colon cancer cells.

5-Fluorouracil (5-FU) is the chemotherapeutic drug of choice for the treatment of metastatic colorectal cancer (CRC). Tumor suppressor candidate 4 (TUSC4), also referred to as nitrogen permease regulator-like 2 (NPRL2), is located at chromosome 3p21.3 and expressed in numerous normal tissues, including the heart, liver, skeletal muscle, kidney, and pancreas. The aim of the present study was to investigate the functional mechanism by which TUSC4 affects sensitivity to 5-FU and to determine its clinical significance in CRC. The results of the present study demonstrated that TUSC4 overexpression increases the sensitivity of HCT116 cells to 5-FU. The IC50 of 5-FU was reduced in cells transduced with TUSC4 compared with negative control (NC) cells, and the effect of TUSC4 on 5-FU sensitivity was time dependent. Following TUSC4 transduction in HCT116 cells, a proportion of the cells were arrested in the G1 phase of the cell cycle, and a reduction in the S phase population was observed. Flow cytometry analysis revealed that TUSC4 transduction and 5-FU treatment increased apoptosis compared with NC cells. The mechanism through which TUSC4 overexpression enhances 5-FU sensitivity involves the downregulation of the function of the PI3K/Akt/mTOR network. Furthermore, 5-FU upregulated caspase-3 and caspase-9, promoting apoptosis in TUSC4-overexpressing cells compared with cells that were transduced with TUSC4 or treated with 5-FU and NC cells. The findings of the present study indicate that TUSC4 has potential as a biomarker for the prediction of the response to 5-FU and prognosis in patients with colorectal cancer and other types of human cancer. TUSC4 may also act as a molecular therapeutic agent for enhancing the patient's response to 5-FU treatment.

Endostar, a novel human recombinant endostatin, attenuates liver fibrosis in CCl4-induced mice.

Decreasing hepatic fibrosis remains one of the major therapeutic challenges in hepatology. The present study aims to evaluate the effect of Endostar on both CCl4-induced liver fibrosis in mice and a hepatic stellate cell (HSC) line. Two main models were studied: (i) a liver fibrosis model was induced in BALB/c mice using CCl4 by intraperitoneal injection for six weeks. Six animal groups were studied: group 1: normal animals; group 2: CCl4-induced liver fibrosis; group 3: CCl4 + Endostar 20 mg/kg/d, six weeks; group 4: CCl4 + Endostar 10 mg/kg/d, six weeks; group 5: CCl4 + Endostar 20 mg/kg/d, four weeks; group 6: CCl4 + Endostar 10 mg/kg/d, four weeks corresponded to different Endostar doses and duration of administration. Liver fibrosis was evaluated by histopathological staining and liver hydroxyproline content. Expressions of collagen type I, α-smooth muscle actin (α-SMA), TGF-ß1 and VEGFR were measured by real-time polymerase chain reaction (PCR). (ii) A liver cell model. HSC-T6 cells were cultured with or without Endostar for 12 h or 24 h. Expressions of collagen type I, α-SMA, and TGF-ß1 were measured by real-time PCR. Collagen I and transforming growth factor ß1 (TGF-ß1) contents in cell supernatant were measured by enzyme-linked immunosorbent assay. As compared to the group without Endostar, liver fibrosis scores and hydroxyproline content were decreased in both Endostar groups (P < 0.05). Moreover, Endostar inhibited the hepatic expression of α-SMA, TGF-ß1, Collagen-1, VEGFR1, and VEGFR2 mRNA (P < 0.05). In the HSC-T6 cell line model, Endostar profoundly inhibited the expression of α-SMA, Collagen-1, and TGF-ß1 mRNA. Expressions of Collagen-1 and TGF-ß1 protein were decreased in the Endostar group as compared to the normal controls in the supernatant of HSC-T6 cells (P < 0.05). Endostar decreased both liver fibrosis in CCl4-induced mice and collagen synthesis in HSCs in vitro. Therefore, this recombinant human endostatin is a promising compound for counteracting liver fibrosis.

Relationship between tumor and peripheral blood NPRL2 mRNA levels in patients with colorectal adenoma and colorectal cancer.

NPRL2 is a tumor suppressor gene involved in the progression of human cancer. The present study investigated whether NPRL2 expression correlates with colorectal cancer (CRC) progression. Colorectal tissue and peripheral blood samples were obtained from 62 patients with CRC, 38 patients with colorectal adenomas and 51 normal controls. NPRL2 mRNA levels in tissue samples and blood were measured using quantitative real-time PCR. NPRL2 protein expression was determined by immunohistochemistry. NPRL2 protein expression in CRCs was significantly lower than in the adenomas or normal colorectal tissue. NPRL2 mRNA expression was significantly decreased in adenomas compared with normal controls (P<0.0001) and it was further decreased in colorectal tumors compared with adenomas (P<0.0001). NPRL2 mRNA levels expression correlated with tumor stage. In addition, NPRL2 mRNA levels in the blood correlated with the levels detected in tumors. Furthermore, receiver operating characteristic (ROC) analysis showed that NPRL2 expression in blood could distinguish colorectal adenomas and CRCs from normal controls. NPRL2 mRNA expression in CRC tumor tissues and peripheral blood correlated with colorectal tumor progression. Based on our findings, we can conclude that NPRL2 mRNA blood levels could be a potentially useful marker for the detection of early stage adenomas and CRCs.

Prevalence of Helicobacter pylori vacA, cagA and iceA genotypes and correlation with clinical outcome.

The aim of this study was to assess the genetic status of cagA, vacA subtype and iceA genotypes of Helicobacter pylori and the relationship with upper gastrointestinal diseases in Northeast China. Gastric biopsies were obtained from 378 patients with upper gastrointestinal diseases and 197 samples were used. The cagA, vacA alleles and iceA genotypes were determined by polymerase chain reaction. CagA was present in 176 (89.3%) of 197 patients. Of the 197 cases, 186 (94.4%) had vacA signal sequence s1c allele, 6 (3%) had s1a and 5 (2.5%) had s1b. The vacA s2 genotype was not detected in our study. VacA middle region sequences, m1 and m2, were found in 20 (10.2%) and 150 (76.1%), respectively. The allelic variant iceA1 (70.1%) was more prevalent than iceA2 (23.4%). The vacA allele s1am2 had a significant relationship with the presence of gastric cancer (p<0.05) and the iceA1 genotype was also associated with gastric cancer (p<0.05). These may be useful risk factors for upper gastrointestinal diseases.