ANXA2 regulates the behavior of SGC-7901 cells

Annexin A protein family: Focusing on the occurrence, progression and treatment of cancer

The annexin A (ANXA) protein family is a well-known tissue-specific multigene family that encodes Ca²⁺ phospholipid-binding proteins. A considerable amount of literature is available on the abnormal expression of ANXA proteins in various malignant diseases, including cancer, atherosclerosis and diabetes. As critical regulatory molecules in cancer, ANXA proteins play an essential role in cancer progression, proliferation, invasion and metastasis. Recent studies about their structure, biological properties and functions in different types of cancers are briefly summarised in this review. We further discuss the use of ANXA as new class of targets in the clinical diagnosis and treatment of cancer.

Identification of Functional Interactome of Gastric Cancer Cells with Helicobacter pylori Outer Membrane Protein HpaA by HPLC-MS/MS

HpaA as an outer membrane protein of Helicobacter pylori (H. pylori) plays a significant role in the adhesion to the human stomach, but the functional relation between HpaA and gastric epithelial cells is still not clear. To screen the interaction between HpaA and cellular proteins in gastric epithelial cells, the HpaA protein from H. pylori 26695 fused with a tag (6× His) was expressed and purified successfully, the secondary structure was estimated by the Circular Dichroism (CD) spectrum, and the purified recombinant protein was used to perform the pull-down assays with gastric cancer cell lines (AGS and SGC-7901) lysates, respectively. The pull-down proteins were identified by high-performance liquid chromatography tandem mass spectrometry system (HPLC-MS/MS). A total of 9 and 13 proteins related were analyzed from AGS and SGC-7901 cell lysates, respectively. ANXA2 was considered as putative HpaA functional partner discovered from lysates of both cell lines with high score and coverage. It is hypothesized that HpaA may be involved in the biological process of regulation of transcription and nucleic acid metabolism during the adhesion of H. pylori to human gastric epithelial cells, and HpaA-binding proteins also be used as targets for the development of antiadhesion drugs against H. pylori.

MicroRNA-206 regulates the epithelial-mesenchymal transition and inhibits the invasion and metastasis of prostate cancer cells by targeting Annexin A2

The present study investigated the molecular mechanism by which microRNA-206 (miR-206) targets Annexin A2 (ANXA2) expression and inhibits the invasion and metastasis of prostatic cancer cells through regulation of the epithelial-mesenchymal transition (EMT). Using bioinformatics analysis, miR-206 was identified as the most promising candidate miRNA that targeted ANXA2. Prostate tissue specimens from 60 patients with prostate cancer, 30 patients with metastatic prostate cancer and 20 patients with benign prostatic hyperplasia (BPH) were examined for ANXA2 protein expression by immunohistochemistry and western blotting and for miR-206 expression by reverse transcription-quantitative polymerase chain reaction. Additionally, human prostate cancer PC-3 cells were transfected with miR-206 mimics, miR-206 inhibitors or a negative control sequence, and expression of ANXA2, E-cadherin and N-cadherin was detected by western blotting. Transwell assays were performed to determine the effect of altered miR-206 expression on the invasive behavior of PC-3 cells. Bioinformatics analysis predicted complementary binding between miR-206 and ANXA2 mRNA. ANXA2 protein expression was detected in a significantly higher proportion of BPH tissues (95%, 19/20) when compared with prostate cancer tissues (51.7%, 31/60; P<0.05). Similarly, ANXA2 was expressed in a significantly higher proportion of metastatic prostate cancer samples than that of prostate cancer samples (P<0.05). Expression of miR-206 was higher than that of ANXA2 in prostate cancer samples, but lower in BPH samples. Inhibition of miR-206 expression in PC-3 cells upregulated ANXA2 and E-cadherin protein expression levels, downregulated N-cadherin and vimentin, and promoted cell invasion in vitro. These data suggested that binding between miRNA-206 and ANXA2 mRNA may regulate EMT signaling, thereby suppressing the invasion and metastasis of prostatic cancer cells.

What gastric cancer proteomic studies show about gastric carcinogenesis?

Gastric cancer is a complex, heterogeneous, and multistep disease. Over the past decades, several studies have aimed to determine the molecular factors that lead to gastric cancer development and progression. After completing the human genome sequencing, proteomic technologies have presented rapid progress. Differently from the relative static state of genome, the cell proteome is dynamic and changes in pathologic conditions. Proteomic approaches have been used to determine proteome profiles and identify differentially expressed proteins between groups of samples, such as neoplastic and nonneoplastic samples or between samples of different cancer subtypes or stages. Therefore, proteomic technologies are a useful tool toward improving the knowledge of gastric cancer molecular pathogenesis and the understanding of tumor heterogeneity. This review aimed to summarize the proteins or protein families that are frequently identified by using high-throughput screening methods and which thus may have a key role in gastric carcinogenesis. The increased knowledge of gastric carcinogenesis will clearly help in the development of new anticancer treatments. Although the studies are still in their infancy, the reviewed proteins may be useful for gastric cancer diagnosis, prognosis, and patient management.