c-erbB-2 Oncoprotein Content in Gastric Cancer and in Adjacent Mucosa

miR-22 inhibits the proliferation, motility, and invasion of human glioblastoma cells by directly targeting SIRT1

Recently, microRNAs (miRNAs), a kind of small and non-coding RNA, can target the downstream molecules. Increasing evidence demonstrates that miRNAs meditate the onset and progression of a variety of tumors. In the present study, we carried out gene transfection, western blot, and reverse transcription PCR (RT-PCR) to explore the role of miR-22 in glioblastoma tissues and cell lines. Here, we verified that the expression of miR-22 was downregulated in glioblastoma tissues and cells rather than matched non-tumor tissues and normal human astrocyte (NHA) cells (p < 0.001). By contrast, SIRT1 messenger RNA (mRNA) and protein were upregulated in glioblastoma tissues and cells (p < 0.001). In vitro miR-22 mimics interfered with cell proliferation, migration, and invasion of U87 and U251 cells. Mechanically, the 3'-untranslated regions (3'-UTRs) of SIRT1 were a direct target of miR-22, leading to the decreased expression of SIRT1 protein in U87 and U251 cells. Meanwhile, miR-22 mimics also inhibited the expression of epidermal growth factor receptor (EGFR) and matrix metallopeptidase 9 (MMP9). In conclusion, miR-22 inhibited cell proliferation, migration, and invasion via targeting the 3'-UTR of SIRT1 in the progression of glioblastoma and miR-22-SIRT1 pathway can be recommended as a potential target for treatment of glioblastoma.

TGF-β Regulates Survivin to Affect Cell Cycle and the Expression of EGFR and MMP9 in Glioblastoma

Transforming growth factor beta (TGF-β) is suggestive of a molecular target for cancer therapy due to its involvement in cell cycle, differentiation, and morphogenesis. Meanwhile, survivin is identified as an apoptosis inhibitor and involved in tumorgenesis. Here, we aimed to investigate the potential associations between TGF-β and survivin in glioblastoma U87 cell line. Survivin small interfering RNA (siRNA), Western blotting, and cell cycle analysis were introduced to detect relevant proteins in TGF-β pathways. In this study, we observed a concentration- and time-dependent increase of survivin expression after treatment with TGF-β1. However, the kinase inhibitors U0126 and LY294002 inhibited the upregulation of survivin in comparison with DMSO. In addition, survivin siRNA effectively abrogated survivin expression in U87 cells, therefore affected cells' entry into the S phase of cell cycle, and then repressed the expression of epidermal growth factor receptor (EGFR) and matrix metalloproteinase 9 (MMP9) in comparison with non-transfection. In conclusion, the present study shows that TGF-β upregulates survivin expression via ERK and PI3K/AKT pathway, leading to glioblastoma cell cycle progression. Thus, the blockade of survivin will allow for the treatment of glioblastoma, partially attributing to the inhibition of EGFR and MMP9 expression.

The impact of Helicobacter pylori on EGF, EGF receptor, and the c-erb-B2 expression

PURPOSE

Increased expression of epidermal growth factor (EGF), its receptor (EGFR), and c-erb-B2 protein, which is homological with the EGF receptor, in gastric mucosa, may play a role in gastric carcinogenesis. We assessed if the infection and eradication of Helicobacter pylori (H. pylori) affects the gastric expression of growth factors and serum gastrin concentrations.

PATIENTS/METHODS

We examined immunohistochemically gastric EGF and both receptors' expression in: gastric cancer (GC; n=29), chronic gastritis with H. pylori infection (GHp+; n=40) before and after eradication and in patients without H. pylori infection (GHp-; n=42).

RESULTS

Before the eradication therapy, gastric mucosal EGF and both receptor's expressions in GHp+ patients were increased compared to GHp- (p<0.05), but were similar to GC. After eradication, EGF and the receptor's expression significantly decreased in the gastric body. Both EGFR and c-erb-B2 expression in the antrum were still higher than in GHp- (p<0.05), and remained comparable to GC.

CONCLUSIONS

In patients with H. pylori infection the gastric mucosal EGF, EGFR, and c-erb-B2 expressions are similar to those observed in gastric cancer. The persistence of the antral expression of receptors after eradication, at a level comparable to the gastric cancer group, suggests their eventual role in the progression of changes initiated by H. pylori toward carcinogenesis.

Signal transduction proteins in tumors from Puerto Rican and Caucasian gastric adenocarcinoma patients: expression differences with potential for specific targeted therapies

Overexpression of the HER2/NEU gene is associated with aggressive behavior and poor prognosis in breast cancer, making the Her2/neu protein a directed-therapy target. Tumors of two Puerto Rican (PR) patients overexpressed Her2/neu and resulting partial clinical responses motivated us to compare Her2/neu expression in PR (n = 101) and Caucasian non-Hispanic (n = 95) patients. Immunohistochemistry of tumors showed overexpression of p-Stat3, Cyclin D1, and Her2/neu, compared to non-neoplastic mucosa. Her2/neu and EGF-R protein levels were statistically significantly different with higher levels of both proteins in the PR group. Importantly, Her2/neu expression was strong and diffuse in tumors with signet-ring morphology, while other histo-pathological subtypes showed higher intra-tumoral Her2/neu heterogeneity than typically observed in breast cancer. Targeted therapies in gastric cancer directed at EGF-R and Hers-2/neu pathways warrant further investigation. These therapies may be especially effective in PR patients and in patients with signet-ring cell morphologies with a dismal prognosis.

Membranous Levels of C-Erbb-2 Oncoprotein in Gastric Cancer: Their Relationship with Clinicopathological Parameters and Their Prognostic Significance

Background

The protein encoded by the c-erbB-2 gene is a membrane receptor expressed in a variety of solid human cancers and directly related to poor prognosis. The objective of this work was to evaluate the clinical value of the quantification of membranous oncoprotein levels in gastric cancer.

Materials and methods

Membranous c-erbB-2 levels were examined by means of a sandwich immunoenzymatic assay in 82 patients with gastric cancer. The median follow-up period for these patients was 16 months. In addition, c-erbB-2 expression was analyzed by immunohistochemistry in 57 gastric carcinomas.

Results

Membranous c-erbB-2 levels ranged widely in the studied tumors (44–112,000 NHU/mg protein). Median c-erbB-2 content was significantly higher in intestinal-type tumors than in diffuse-type tumors (p=0.01). In addition, high levels of c-erbB-2 were significantly associated with shorter relapse-free survival and overall survival in patients with resectable gastric carcinomas (p=0.01 and p=0.04, respectively). However, the correlation between immunohistochemistry and ELISA determinations did not reach statistical significance.

Conclusion

Our results suggest a potential prognostic value of membranous c-erbB-2 quantification by immunoenzymatic assay in gastric cancer. However, its possible role in the selection of patients with a view to the possible introduction of Herceptin as a novel drug against gastric cancer is at present uncertain.

Clinical significance of the epidermal growth factor receptor and HER2 receptor in resectable gastric cancer

BACKGROUND

Epidermal growth factor receptor (EGFR or HER1) and its homolog c-erbB-2 (HER2) are membrane receptors. Both EGFR and HER2 genes are overexpressed in a variety of solid human cancers and are related to poor prognosis of the patients. The objective of this work was to evaluate the EGFR and HER2 contents in resectable gastric cancer, their possible relationship with clinicopathologic parameters of tumors, and their prognostic significance.

METHODS

This was a prospective analysis of 63 patients with resectable gastric carcinomas, with a mean follow-up period of 40.7 months. Membranous EGFR levels were examined by radioligand binding assays, and cytosolic HER2 levels were examined by means of an immunoenzymatic assay.

RESULTS

There was a wide variability of EGFR (1-1,239 fmol/mg of protein) and HER2 (7-20,863 NHU/mg of protein) levels in tumors. There was no significant correlation between these levels and patient or tumor characteristics. However, high levels of EGFR and HER2 were significantly associated with a shorter overall survival period (P =.03 and P =.02, respectively).

CONCLUSIONS

There is a wide variability in membranous EGFR levels and in cytosolic HER2 levels in gastric cancer, which seems to be related to the biological heterogeneity of these tumors. In addition, high tumor EGFR and HER2 levels were associated with an unfavorable outcome in patients with resectable gastric cancer.