Adhesion of different cell cycle human hepatoma cells to endothelial cells and roles of integrin β1

The difference in Ezrin-pAkt signaling axis between lepidic and papillary predominant invasive adenocarcinomas of the lung

PURPOSE

Histologic classification of invasive lung adenocarcinomas by predominant subtype has prognostic value. Papillary predominant adenocarcinoma (PPA) reportedly shows poorer prognosis than lepidic predominant adenocarcinoma (LPA); however, biological differences between PPA and LPA are unclear. The purpose of this study was to clarify biological differences between PPA and LPA.

METHODS

Clinicopathological characteristics of invasive 62 PPAs and 117 LPAs smaller than 30 mm were investigated. Furthermore, we compared immunochemical staining scores of 9 molecular markers (E-cadherin, S100A4, fibronectin, integrinβ1, ezrin, GLUT1, ALDH1, SOX2 and Nanog) between PPA and LPA. We performed Western blot analysis using ezrin shRNA-knockdown lung adenocarcinoma cell lines to examine whether molecules that are highly expressed in PPA, such as ezrin, affect pAkt. Finally, we performed immunochemical staining to compare pAkt expression level in PPA and LPA.

RESULTS

Lymphovascular and pleural invasion and lymph node metastasis were significantly more often detected in PPA than in LPA (lymphatic permeation: 31 vs 3 %, vascular invasion: 35 vs 3 %, pleural invasion: 29 vs 5 %, lymph node metastasis: 18 vs 1 %; all P < 0.01). Immunohistochemical (IHC) study revealed that expression score of ezrin was significantly higher in PPA than in LPA (38.3 vs 15.0; P < 0.01). The level of pAkt decreased in shEzrin-induced PC-9 and A549 cancer cells. Moreover, the IHC staining score of pAkt was significantly higher in PPA than in LPA (13.3 vs 0.0; P < 0.01).

CONCLUSIONS

Our results show that the activation of the ezrin-pAkt signaling axis is associated with the more aggressive clinicopathological features of PPA compared with LPA.

Expression of integrin β1 and its significance in squamous cell carcinoma of the cervix

The aim of the present study was to examine the expression of integrin β1 in squamous cell carcinoma (SCC) of the cervix and its association with the clinicopathological features of patients. The expression of integrin β1 in 87 SCC cervical tissues and 32 normal cervical tissues was detected using an enzyme-linked immunosorbent assay, western blot analysis and the immunohistochemical streptavidin-peroxidase method. Integrin β1 expression was greater in SCC cervical tissues compared with that in normal cervical tissues (P<0.05), and its mean expression level in the SCC cervical tissues was also markedly higher compared with that in the normal cervical tissues (P<0.05). In terms of the association between the expression of integrin β1 with clinicopathological features, patients with stage IIA SCC had higher integrin β1 positive rates compared with patients with stage I SCC (P<0.05). The integrin β1 positive rates in SCC tissues with histological grade 3 were also significantly higher than that in the SCC tissues with histological grade 1 (P<0.05). Furthermore, patients with cervical SCC with lymph node metastasis showed increased integrin β1 positive expression compared with those without lymph node metastasis (P<0.05). In conclusion, the expression of integrin β1 protein in cervical SCC tissues was significantly higher than that in the normal cervical tissues, and it increased with the clinical stage and the degree of malignancy.

Inhibition of fibroblast adhesion by covalently immobilized protein repellent polymer coatings studied by single cell force spectroscopy

Cochlea implants (CI) restore the hearing in patients with sensorineural hearing loss by electrical stimulation of the auditory nerve via an electrode array. The increase of the impedance at the electrode-tissue interface due to a postoperative connective tissue encapsulation leads to higher power consumption of the implants. Therefore, reduced adhesion and proliferation of connective tissue cells around the CI electrode array is of great clinical interest. The adhesion of cells to substrate surfaces is mediated by extracellular matrix (ECM) proteins. Protein repellent polymers (PRP) are able to inhibit unspecific protein adsorption. Thus, a reduction of cell adhesion might be achieved by coating the electrode carriers with PRPs. The aim of this study was to investigate the effects of two different PRPs, poly(dimethylacrylamide) (PDMAA) and poly(2-ethyloxazoline) (PEtOx), on the strength and the temporal dynamics of the initial adhesion of fibroblasts. Polymers were immobilized onto glass plates by a photochemical grafting onto method. Water contact angle measurements proved hydrophilic surface properties of both PDMAA and PEtOx (45 ± 1° and 44 ± 1°, respectively). The adhesion strength of NIH3T3 fibroblasts after 5, 30, and 180 s of interaction with surfaces was investigated by using single cell force spectroscopy. In comparison to glass surfaces, both polymers reduced the adhesion of fibroblasts significantly at all different interaction times and lower dynamic rates of adhesion were observed. Thus, both PDMAA and PEtOx represented antiadhesive properties and can be used as implant coatings to reduce the unspecific ECM-mediated adhesion of fibroblasts to surfaces.

KAI1 gene suppresses invasion and metastasis of hepatocellular carcinoma MHCC97-H cells in vitro and in animal models

BACKGROUND

Downregulation of KAI1 gene expression has been found in many types of cancer cells and is closely related to cancer invasion and metastasis. This study was aimed at investigating the effects and possible underlying mechanisms of KAI1 gene on invasion and metastasis of human hepatocellular carcinoma (HCC).

METHODS

The invasive ability, visco-elastic properties and cell adhesion forces were analysed in different HCC cells originating from the MHCC97-H cell line transfected with either the sense or the antisense KAI1 expression plasmid. Tumuorigenicity, metastatic abilities, extracellular matrix (ECM) and intercellular adhesion molecule-1 (ICAM-1) expression were also evaluated in the nude mouse models of the xenografted and orthotopic liver cancer cells.

RESULTS

Compared with their parental cells, in the HCC cells transfected with the sense KAI1 gene, the invasive ability in vitro was significantly decreased (P<0.01); the cellular elastic coefficients K(1), K(2) and mu were significantly higher (P<0.05); the cells adhesion forces to fibronectin were significantly lower (P<0.01). The sense KAI1 gene transfection into the cancer cells also inhibited their invasion and lung metastasis in the orthotopic liver cancer nude mice. However, the opposite changes were observed in the HCC cells transfected with the antisense KAI1 gene. KAI1 gene transfection also affected ECM and ICAM-1 expression in the transplanted liver cancer.

CONCLUSION

The KAI1 gene plays an important role in the invasion and metastasis of human HCC and its upregulation in HCC cells suppresses their invasive and metastatic abilities. KAI1 gene functioned as a metastasis inhibitor by regulating the HCC cell biophysical behaviours including aggregation, adhesion, motility and visco-elastic properties.

Synergistic effect of oxymatrine and angiogenesis inhibitor NM-3 on modulating apoptosis in human gastric cancer cells

AIM: To investigate the synergistic effect of oxymatrine (OM) and angiogenesis inhibitor NM-3 on modulating apoptosis in human gastric cancer cell lines SGC-7901, MKN-45, MKN-74.

METHODS: Human gastric cancer lines SGC-7901, MKN-45, MKN-74 were treated with OM in the absence and presence of NM-3. The inhibitory rates were detected by MTT assay. Synergistic effect of OM and NM-3 on the growth of survivin, bcl-2, bax and p53 in SGC-7901 cells were examined by semiquantitative RT-PCR and Western blotting, and their growth inhibitory effects were also observed on SGC-7901 tumor xenograft in nude mice.

RESULTS: OM combined with NM-3 exhibited a synergistic inhibitory effect on the growth of SGC-7901, MKN-45 and MKN-74 cells in a time-dependent manner. Twenty-four hours after treatment with OM, NM-3 alone and their combination, mRNA expression of survivin and bcl-2 in SGC-7901 cells decreased, p53 mRNA expression increased. OM (4 g/L) combined with NM-3 significantly increased the expression of p53 mRNA and decreased the expression of survivin and bcl-2 compared with either agent alone (193% ± 34% vs 129% ± 12%; 44% ± 18% vs 92% ± 18%; 36 ± 17% vs 93% ± 23%, P < 0.05). Western blotting showed that the synergistic effect of OM and NM-3 on protein translation of survivin, bcl-2 and p53 was in accordance with their mRNAs. Furthermore, OM/NM-3 combination obviously exhibited antitumor growth effect in xenografted human gastric cancer cells SGC-7901 compared with either agent alone.

CONCLUSION: OM combined with NM-3 has synergistic inhibitory effects on human gastric cancer cells in vitro and can suppress the growth of xenografted human gastric cancer cells SGC-7901 in vivo.

Gene expression analysis in LLC-PK1 renal tubular cells by atrial natriuretic peptide (ANP): correlation of homologous human genes with renal response

We used human DNA microarray to explore the differential gene expression profiling of atrial natriuretic peptide (ANP)-stimulated renal tubular epithelial kidney cells (LLC-PK1) in order to understand the biological effect of ANP on renal kidney cell's response. Gene expression profiling revealed 807 differentially expressed genes, consisting of 483 up-regulated and 324 down-regulated genes. The bioinformatics tool was used to gain a better understanding of differentially expressed genes in porcine genome homologous with human genome and to search the gene ontology and category classification, such as cellular component, molecular function and biological process. Four up-regulated genes of ATP1B1, H3F3A, ITGB1 and RHO that were typically validated by real-time quantitative PCR (RT-qPCR) analysis serve important roles in the alleviation of renal hypertrophy as well as other related effects. Therefore, the human array can be used for gene expression analysis in pig kidney cells and we believe that our findings of differentially expressed genes served as genetic markers and biological functions can lead to a better understanding of ANP action on the renal protective system and may be used for further therapeutic application.

What is hidden in the pannexin treasure trove: the sneak peek and the guesswork

Connexins had been considered to be the only class of the vertebrate proteins capable of gap junction formation; however, new candidates for this function with no homology to connexins, termed pannexins were discovered. So far three pannexins were described in rodent and human genomes: Panx1, Panx2 and Panx3. Expressions of pannexins can be detected in numerous brain structures, and now found both in neuronal and glial cells. Hypothetical roles of pannexins in the nervous system include participating in sensory processing, hippocampal plasticity, synchronization between hippocampus and cortex, and propagation of the calcium waves supported by glial cells, which help maintain and modulate neuronal metabolism. Pannexin also may participate in pathological reactions of the neural cells, including their damage after ischemia and subsequent cell death. Recent study revealed non-gap junction function of Panx1 hemichannels in erythrocytes, where they serve as the conduits for the ATP release in response to the osmotic stress. High-throughput studies produced some evidences of the pannexin involvement in the process of tumorigenesis. According to brain cancer gene expression database REMBRANDT, PANX2 expression levels can predict post diagnosis survival for patients with glial tumors. Further investigations are needed to verify or reject hypotheses listed.

Expression of β2-integrin on leukocytes in liver cirrhosis

AIM: To analyze β2-integrin expression on blood leukocytes in liver cirrhosis.

METHODS: In 40 patients with liver cirrhosis and 20 healthy individuals, the evaluation of expression of CD11a (LFA-1α), CD11b (Mac-1α), CD11c (αX) and CD49d (VLA-4α) on peripheral blood leukocytes was performed using flow cytometry. The analysis was carried out in groups of patients divided into B and C according to Child-Pugh’s classification.

RESULTS: An increased CD11a, CD11b, CD11c and CD49d integrin expression was observed on peripheral blood leukocytes in liver cirrhosis. The integrin levels were elevated as the advancement of liver failure progressed. The highest expression of integrins occurred predominantly on monocytes. A slight expression of VLA-4 was found on lymphocytes and granulocytes and it increased together with liver failure. A positive correlation was noted between median intensity of fluorescence (MIF) expression on polymorphonuclear cells of CD11a and CD11c and CD49d (r = 0.42, P < 0.01; r = 053, P < 0.01, respectively) in liver cirrhosis stage C. However, no correlation was observed between integrin expression on leukocytes. The concentrations of sICAM-1, sVCAM-1, and TNFα, were significantly elevated in liver cirrhosis.

CONCLUSION: β2-integrin expression on leukocytes increases in liver cirrhosis decompensated as the stage of liver failure increases, which is a result of permanent activation of leukocytes circulating through the inflamed liver environment. β2-integrin expression on circulating leukocytes can intensify liver cirrhosis.

Microarray analyses in bladder cancer cells: Inhibition of hTERT expression down-regulates EGFR

The human telomerase reverse transcriptase (hTERT) contributes to the immortal phenotype of the majority of cancers. Targeting hTERT by transfection with antisense oligonucleotides (AS-ODNs) induced immediate growth inhibition in human bladder cancer (BCa) cells. The molecular basis of the antiproliferative capacity of hTERT AS-ODNs was investigated by oligonucleotide microarray analyses and was compared to effects caused by siRNA-mediated knock-down of hTERT in EJ28 BCa cells. Two different AS-ODNs -- both down-regulated the expression of hTERT -- changed the expression of different genes mainly involved in stress response (including EGR1, ATF3 and GDF15), but without an association to telomerase function. This indicates that the immediate growth inhibition was caused, at least in part, by off-target effects. In comparison to that the blockade of the expression of hTERT using 2 different siRNAs was accompanied by the down-regulation of the oncogenes FOS-like antigen 1 (FOSL1) and epidermal growth factor receptor (EGFR), known to be overexpressed in BCa. We show here for the first time that repression of the hTERT transcript number decreased the expression of EGFR both at the mRNA and protein levels, suggesting a potential new function of hTERT in the regulation of EGFR-stimulated proliferation. Furthermore, the suppression of hTERT by siRNAs caused an enhancement of the antiproliferative capacity of the chemotherapeutics mitomycin C and cisplatin. The results presented herein may support the hypothesis that hTERT promotes the growth of tumor cells by mechanisms independent from telomere lengthening. The detailed clarification of these processes will shed light on the question, whether telomerase inhibitors might constitute suitable anticancer tools.