Screening and Identification of Small Peptides Targeting Fibroblast Growth Factor Receptor2 using a Phage Display Peptide Library

The human Fibroblast Growth Factor Receptor (FGFR) family comprises four members, namely, FGFR1, FGFR2, FGFR3, and FGFR4, that are involved in various ...

Guangdong Provincial Key Laboratory of Bioengineering Medicine

To study the functions of human Fibroblast growth factor receptor 2IIIc (FGFR2IIIc) gene in cancer cells, breast cancer cells MDA-MB-231 were infected by recombinant adenoviruses containing FGFR2IIIc and its S252W mutant, respectively. FGFR2IIIc gene was amplified from an existing plasmid and its S252W mutant was obtained by overlapping extension PCR. These two genes were separately cloned into the adenoviral shuttle plasmid pAdTrack-CMV, confivmed by DNA sequencing linearized, and co-transformed into Escherichia coli BJ-5183 with the adenoviral vector pAdEasy-1. The resulting recombinant expression vectors Ad-FGFR2IIIc and Ad-FGFR2IIIcS252W were linearized and transfected into HEK293A cells to get adenoviral particles. GFP was used to verify the gene expression. The recombinant adenoviral particles were harvested, titrated, and then infected MDA-MB-231 cells. The expression of FGFR2IIIc and its S252W mutant were examined by RT-PCR and Western blotting, and the effect of these recombinant adenoviruses on MDA-MB-231 cell proliferation was analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry. The results showed the recombinant adenoviral particles could infect MDA-MB-231 cells and express the target proteins. MTT showed that both FGFR2IIIc and its S252W mutant inhibited MDA-MB-231 cell proliferation, but the mutant was more effective. Flow cytometry showed that both FGFR2IIIc and its S252W mutant arrested MDA-MB-231 cell cycle at G0/G1 phase, resulting in low cell proliferation.

[Experssion of human FGFR2IIIc and its S252W mutant in MDA-MB-231 breast cancer cells with adenovirus vectors].

Bone is one of the most common metastatic sites for breast cancer. In this study, we observed a promoting effect of osteoblast-conditioned medium (OCM) on the migration of MCF-7, a noninvasive cell line of breast cancer cells. Cytokine antibody array was used to compare the cytokines of OCM with the conditioned medium of non-differentiated osteoblast cells, which consequently revealed factors related to migration, such as IL8, IL6, CSF2 (G-CSF), CSF3 (GM-CSF), and TNFRSF11B (osteoprotegerin). The expression of genes related to migration was also estimated with a PCR array, which showed that 9 genes were upregulated and 26 genes downregulated. Moreover, activated p38, ERK, and AKT pathways were found in the OCM treatment group. This finding indicated the migration ability of breast cancer cells, which move toward the bone depending on the presence of specific cytokines in its surrounding microenvironment. 

Cytokines in osteoblast-conditioned medium promote the migration of breast cancer cells.

Pituitary adenylate cyclase-activating peptide I receptor (PAC1R) is member of the B class of G protein-coupled seven-transmembrane receptors, with molecular functions associated with neural cell differentiation, regeneration and the inhibition of apoptosis. However, the integrity of the protein structure is difficult to be determined in vitro. In the present study, the physicochemical properties of PAC1R were analyzed, the extracellular, transmembrane and intracellular regions were constructed and a three-dimensional structure model of PAC1R was produced using extracellular loop region optimization and the energy minimization homology modeling method. Preliminary studies on the PAC1R protein and ligand interactions used a molecular docking method. The results indicated that the interaction sites of PAC1R were at Ile63, Ser100 and Gln105. These were the sites where the PAC1R combined with a hydrazide small molecule inhibitor. This study provides a theoretical basis for further studies on the model for the development of PAC1R target drugs.

Homology modeling and molecular docking of human pituitary adenylate cyclase‑activating polypeptide I receptor.

Pituitary adenylate cyclase‑activating polypeptide (PACAP) is a type of neuropeptide with multiple biological functions. However, it has a short half‑life period in the body, ~3 to 5 min, restricting its further development as a drug that can promote the recovery of nerve injury. In vitro and in vivo experiments have shown that PACAP can repair the epithelial cell on the surface of the injured cornea, as PACAP can act on the trigeminal nerve cell to secrete other active neurotransmitters, which can promote corneal epithelial cell proliferation and differentiation. In the present study, PACAP is connected to the N‑terminal agrin domain (NtA) with a genetic engineering method, which allows the function of repairing the injured nerve. Notably, the recombinant polypeptide can interact with laminin, improving the biological effect of PACAP in repairing the injured nerve. In the study, the recombinant protein was constructed by combining PACAP38 and NtA by genetic engineering, and it is expressed in the pronucleus escherichia coli. The recombinant protein, PACAP38‑NtA, is obtained with a two‑step purification method, including anion‑exchange chromatography and Ni‑affinity chromatography, with the purity reaching >90%. The in vitro experiment has shown that this recombinant protein not only has the neurotrophy and neural restoration function of PACAP, but also has the function of an anchoring protein as laminin interacts with NtA. According to the in vitro anti‑apoptosis, PC12 axon growth and ELISA experiments, this protein has the biological activity of a recombinant protein. PACAP38‑NtA also has an anchoring function as NtA and laminin interact with good biological activity.

Expression, identification and biological effects of the novel recombination protein, PACAP38-NtA, with high bioactivity.

Recent studies indicate important roles for long noncoding RNAs (lncRNAs) as essential regulators of myogenesis and adult skeletal muscle regeneration. However, the specific roles of lncRNAs in myogenic differentiation of adult skeletal muscle stem cells and myogenesis are still largely unknown. Here we identify a lncRNA that is specifically enriched in skeletal muscle (myogenesis-associated lncRNA, in short, lnc-mg). In mice, conditional knockout of lnc-mg in skeletal muscle results in muscle atrophy and the loss of muscular endurance during exercise. Alternatively, skeletal muscle-specific overexpression of lnc-mg promotes muscle hypertrophy. In vitro analysis of primary skeletal muscle cells shows that lnc-mg increases gradually during myogenic differentiation and its overexpression improves cell differentiation. Mechanistically, lnc-mg promotes myogenesis, by functioning as a competing endogenous RNA (ceRNA) for microRNA-125b to control protein abundance of insulin-like growth factor 2. These findings identify lnc-mg as a novel noncoding regulator for muscle cell differentiation and skeletal muscle development.

Lnc-mg is a long non-coding RNA that promotes myogenesis.

Cancer-associated fibroblasts (CAFs) are believed to influence tumor behavior and clinical outcomes. We previously showed that conditioned medium (CM) from CAFs induces proliferation and motility of esophageal squamous cell carcinoma (ESCC) cells. Here, we investigated the molecular mechanisms by which the CAF-secreted proteins induce ESCC development and progression. Using antibody arrays, we identified urokinase plasminogen activator (uPA) as one of the main proteins whose release was increased in CAFs compared to normal fibroblasts (NFs). Immunohistochemical analysis of pathological sections showed that uPA-positive cells were localized at the boundaries of tumor and stroma tissues, in stroma between tumor nests, and within the tumors. Increased stromal uPA levels (132/146 cases) correlated with tumor invasion (p < 0.05) and overall survival of ESCC patients (p < 0.05). In vitro assays showed that uPA promotes ESCC cell proliferation, migration, and invasion via PI3K/AKT and ERK signaling pathways. In vivo, anti-uPA antibody suppressed tumor growth in ESCC xenografts. These results suggest that uPA released from stroma, and especially from CAFs, might be a predictive marker for ESCC diagnosis and prognosis, as well as an effective therapeutic target.

Urokinase plasminogen activator secreted by cancer-associated fibroblasts induces tumor progression via PI3K/AKT and ERK signaling in esophageal squamous cell carcinoma.

Resistance to platinum-based combination chemotherapy is the main cause of poor prognosis in patients with advanced esophageal squamous cell carcinoma (ESCC). Previously, we showed that CACNA2D3 (voltage-dependent subunit alpha 2 delta 3 of a calcium channel complex) was significantly downregulated and functioned as a tumor suppressor in ESCC, but its role in the chemosensitivity of ESCC to cisplatin remained unknown. Here, we found that the expression of CACNA2D3 was significantly associated with poor platinum response in ESCC patients from the Gene Expression Omnibus database. Overexpression of CACNA2D3 increased sensitivity to cisplatin in ESCC , whereas knockdown of CACNA2D3 increased cisplatin resistance. CACNA2D3 promoted cisplatin-induced apoptosis by modulating intracellular Ca stores.  experiments further showed that overexpression of CACNA2D3 enhanced cisplatin anti-tumor effects in a xenograft mouse model. CACNA2D3 overexpression also resulted in the attenuation of PI3K and Akt phosphorylation. Treatment with the PI3K/Akt inhibitor LY294002 restored the chemosensitivity of CACAN2D3-knockdown cells to cisplatin. In conclusion, the results of the current study indicate that CACAN2D3 enhances the chemosensitivity of ESCC to cisplatin via inducing Ca-mediated apoptosis and suppressing PI3K/Akt pathways. Therefore, regulating the expression of CACNA2D3 is a potential new strategy to increase the efficacy of cisplatin in ESCC patients.

CACNA2D3 Enhances the Chemosensitivity of Esophageal Squamous Cell Carcinoma to Cisplatin via Inducing Ca-Mediated Apoptosis and Suppressing PI3K/Akt Pathways.

Esophageal cancer is the eighth most common malignant tumor worldwide, of which esophageal squamous cell carcinoma (ESCC) is the dominant histological subtype. A drug shortage for ESCC therapy triggered us to explore the roles of fibroblast growth factor receptor 2 (FGFR2) and its upstream regulator miR-671-5p in ESCC progression. We compared the levels of FGFR2 and miR-671-5p between human ESCC tissues and their matched normal esophageal tissues and found an association between higher levels of FGFR2 and lower levels of miR-671-5p in ESCC tissues. High levels of FGFR2 resulted in the activation of the ERK and AKT pathways and a promotion of ESCC progression. High levels of miR-671-5p specifically reduced the expression of FGFR2 and suppressed ESCC progression in both in vitro nd in vivo models. Therefore, suppressing FGFR2 and enhancing miR-671-5p expression may be the right approaches for ESCC therapy.

Xiaojia Chen

Institute of Biomedicine & Department of Cell Biology,
Jinan University,
National Engineering Research Center of Genetic Medicine,
Institute of Biomedicine & Department of Cell Biology, Jinan University, National Engineering Research Center of Genetic Medicine

Guangdong Provincial Key Laboratory of Bioengineering Medicine

Screening and Identification of Small Peptides Targeting Fibroblast Growth Factor Receptor2 using a Phage Display Peptide Library