Mechanism of antitumor effect of a novel bFGF binding peptide on human colon cancer cells

Identification of cofilin-1 as a novel mediator for the metastatic potentials and chemoresistance of the prostate cancer cells

Prostate cancer (PCa) is the most common malignancy among men. Tumor metastasis and chemoresistance contribute to the major cause of the mortality. In this study, we compared the protein profiles of two prostate cancer cell lines with different metastatic potentials, and identified cofilin-1 (CFL1) was one of the most differentially expressed proteins between two cell lines. Further results suggested that cofilin-1 promoted the remodeling of F-actin cytoskeleton, and enhanced the proliferation, migration and invasion of the prostate cancer cells via activation of P38 MAPK signaling pathway. In addition, cofilin-1 elevated the expression and drug efflux activity of multidrug resistance protein 1 (MDR1) by P38 MAPK signaling pathway, resulting in decrease of the adriamycin-induced apoptosis as well as the lytic cell death, and the subsequent resistance against adriamycin. Collectively, cofilin-1 might serve as a novel target candidate for both inhibiting the metastasis and reversing the chemoresistance of PCa.

Identification of galectin-1 as a novel mediator for chemoresistance in chronic myeloid leukemia cells

Multidrug resistance protein-1 (MDR1) has been proven to be associated with the development of chemoresistance to imatinib (Glivec, STI571) which displays high efficacy in treatment of BCR-ABL-positive chronic myelogenous leukemia (CML). However, the possible mechanisms of MDR1 modulation in the process of the resistance development remain to be defined. Herein, galectin-1 was identified as a candidate modulator of MDR1 by proteomic analysis of a model system of leukemia cell lines with a gradual increase of MDR1 expression and drug resistance. Coincidently, alteration of galectin-1 expression triggers the change of MDR1 expression as well as the resistance to the cytotoxic drugs, suggesting that augment of MDR1 expression engages in galectin-1-mediated chemoresistance. Moreover, we provided the first data showing that NF-κB translocation induced by P38 MAPK activation was responsible for the modulation effect of galectin-1 on MDR1 in the chronic myelogenous leukemia cells. Galectin-1 might be considered as a novel target for combined modality therapy for enhancing the efficacy of CML treatment with imatinib.

Prediction of novel target genes and pathways involved in irinotecan-resistant colorectal cancer

Background

Acquired drug resistance to the chemotherapeutic drug irinotecan (the active metabolite of which is SN-38) is one of the significant obstacles in the treatment of advanced colorectal cancer (CRC). The molecular mechanism or targets mediating irinotecan resistance are still unclear. It is urgent to find the irinotecan response biomarkers to improve CRC patients’ therapy.

Methods

Genetic Omnibus Database GSE42387 which contained the gene expression profiles of parental and irinotecan-resistant HCT-116 cell lines was used. Differentially expressed genes (DEGs) between parental and irinotecan-resistant cells, protein-protein interactions (PPIs), gene ontologies (GOs) and pathway analysis were performed to identify the overall biological changes. The most common DEGs in the PPIs, GOs and pathways were identified and were validated clinically by their ability to predict overall survival and disease free survival. The gene-gene expression correlation and gene-resistance correlation was also evaluated in CRC patients using The Cancer Genomic Atlas data (TCGA).

Results

The 135 DEGs were identified of which 36 were upregulated and 99 were down regulated. After mapping the PPI networks, the GOs and the pathways, nine genes (GNAS, PRKACB, MECOM, PLA2G4C, BMP6, BDNF, DLG4, FGF2 and FGF9) were found to be commonly enriched. Signal transduction was the most significant GO and MAPK pathway was the most significant pathway. The five genes (FGF2, FGF9, PRKACB, MECOM and PLA2G4C) in the MAPK pathway were all contained in the signal transduction and the levels of those genes were upregulated. The FGF2, FGF9 and MECOM expression were highly associated with CRC patients’ survival rate but not PRKACB and PLA2G4C. In addition, FGF9 was also associated with irinotecan resistance and poor disease free survival. FGF2, FGF9 and PRKACB were positively correlated with each other while MECOM correlated positively with FGF9 and PLA2G4C, and correlated negatively with FGF2 and PRKACB after doing gene-gene expression correlation.

Conclusion

Targeting the MAPK signal transduction pathway through the targeting of the FGF2, FGF9, MECOM, PLA2G4C and PRKACB might increase tumor responsiveness to irinotecan treatment.

Glycomics expression analysis of sulfated glycosaminoglycans of human colorectal cancer tissues and non-neoplastic mucosa by electrospray ionization mass spectrometry

Objective

To determine the presence of glycosaminoglycans in the extracellular matrix of connective tissue from neoplastic and non-neoplastic colorectal tissues, since it has a central role in tumor development and progression.

Methods

Tissue samples from neoplastic and non-neoplastic colorectal tissues were obtained from 64 operated patients who had colorectal carcinoma with no distant metastases. Expressions of heparan sulphate, chondroitin sulphate, dermatan sulphate and their fragments were analyzed by electrospray ionization mass spectrometry, with the technique for extraction and quantification of glycosaminoglycans after proteolysis and electrophoresis. The statistical analysis included mean, standard deviation, and Student’s t test.

Results

The glycosaminoglycans extracted from colorectal tissue showed three electrophoretic bands in agarose gel. Electrospray ionization mass spectrometry showed characteristic disaccharide fragments from glycosaminoglycans, indicating their structural characterization in the tissues analyzed. Some peaks in the electrospray ionization mass spectrometry were not characterized as fragments of sugars, indicating the presence of fragments of the protein structure of proteoglycans generated during the glycosaminoglycan purification. The average amount of chondroitin and dermatan increased in the neoplastic tissue compared to normal tissue (p=0.01). On the other hand, the average amount of heparan decreased in the neoplastic tissue compared to normal tissue (p= 0.03).

Conclusion

The method allowed the determination of the glycosaminoglycans structural profile in colorectal tissue from neoplastic and non-neoplastic colorectal tissue. Neoplastic tissues showed greater amounts of chondroitin sulphate and dermatan sulphate compared to non-neoplastic tissues, while heparan sulphate was decreased in neoplastic tissues.

Process of hepatic metastasis from pancreatic cancer: biology with clinical significance

PURPOSE

Pancreatic cancer shows a remarkable preference for the liver to establish secondary tumors. Selective metastasis to the liver is attributed to the development of potential microenvironment for the survival of pancreatic cancer cells. This review aims to provide a full understanding of the hepatic metastatic process from circulating pancreatic cancer cells to their settlement in the liver, serving as a basic theory for efficient prediction and treatment of metastatic diseases.

METHODS

A systematic search of relevant original articles and reviews was performed on PubMed, EMBASE and Cochrane Library for the purpose of this review.

RESULTS

Three interrelated phases are delineated as the contributions of the interaction between pancreatic cancer cells and the liver to hepatic metastasis process. Chemotaxis of disseminated pancreatic cancer cells and simultaneous defensive formation of platelets or neutrophils facilitate specific metastasis toward the liver. Remodeling of extracellular matrix and stromal cells in hepatic lobules and angiogenesis induced by proangiogenic factors support the survival and growth of clinical micrometastasis colonizing the liver. The bimodal role of the immune system or prevalence of cancer cells over the immune system makes metastatic progression successfully proceed from micrometastasis to macrometastasis.

CONCLUSIONS

Pancreatic cancer is an appropriate research object of cancer metastasis representing more than a straight cascade. If any of the successive or simultaneous phases, especially tumor-induced immunosuppression, is totally disrupted, hepatic metastasis will be temporarily under control or even cancelled forever. To shrink cancers on multiple fronts and prolong survival for patients, novel oral or intravenous anti-cancer agents covering one or different phases of metastatic pancreatic cancer are expected to be integrated into innovative strategies on the premise of safety and efficacious biostability.

Sulfatase 1 (hSulf-1) reverses basic fibroblast growth factor-stimulated signaling and inhibits growth of hepatocellular carcinoma in animal model

The human sulfatase 1 (hSulf-1) gene encodes an endosulfatase that functions to inhibit the heparin-binding growth factor signaling, including the basic fibroblast growth factor (bFGF)-mediated pathway, by desulfating the cell surface heparan sulfate proteoglycans (HSPGs). bFGF could stimulate cell cycle progression and inhibit cell apoptosis, this biological effect can be reversed by hSulf-1. However, molecular mechanisms have not been fully reported. In the current study, by reactivation of hSulf-1 expression and function in the hSulf-1-negative hepatocellular carcinoma (HCC) cell lines and HCC xenograft tumors, we found that hSulf-1 blocked the bFGF effect on the promotion of cell cycle and inhibition of apoptosis. The bFGF-stimulated activation of protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) pathways was suppressed by hSulf-1, which led to a decreased expression of the target genes Cyclin D1 and Survivin, then finally induced cell cycle arrest and apoptosis in HCC cells. Our data suggested that hSulf-1 may be a suitable target for cancer therapy.

A novel FGF2 antagonist peptide P8 with potent antiproliferation activity

Some fibroblast growth factors (FGFs) play a critical role in tumorigenesis and progression. Among them, FGF2 was highly expressed in some tumors, and antagonists binding to FGF2 can suppress the growth of tumor cells. Therefore, FGF2 has been considered as an important target in cancer therapy. In this study, we identified a novel FGF2-binding short peptide (P8, PLLQATAGGGS-NH2) using phage display technology and alanine scanning. The P8 peptide suppressed FGF2-induced proliferation with no cytotoxic effect on cells, arrested the cycle at the G0/G1 phase in B16-F10 cells, and downregulated the activation of fibroblast growth factor receptor substrate 2α (FRS2α)/ERK cascade in B16-F10, NIH-H460, and SGC-7901 cells. Besides, P8 peptide can also inhibit the phosphorylation of FRS2α stimulated by FGF1 and KGF2. These implied that P8 peptide may develop as a multi-target antagonist peptide contributing to tumor treatment.

P7 peptides targeting bFGF sensitize colorectal cancer cells to CPT-11

The low survival rate of patients with colorectal cancer (CRC) is mainly due to the drug resistance of tumor cells to chemotherapeutic agents. It has been reported that basic fibroblast growth factor (bFGF) is an essential factor involved in the epigenetic mechanisms of drug resistance, which provides a novel potential target for improving the sensitivity of tumor cells to chemotherapeutic agents. In this study, we first demonstrate that a novel bFGF antagonist, peptide P7, previously isolated by phage display technology, reversed bFGF-induced resistance to irinotecan hydrochloride (CPT-11), and counteracted the anti-apoptotic effects of bFGF on CPT-11-treated HT-29 cells. Further experiments indicated that the inhibition of Akt activation, the suppression of bFGF internalization, the increase in the Bax to Bcl-2 ratio and the downregulation of cytokeratin 8 (CK8) by P7 may contribute to the counteracting of the anti-apoptotic effects of bFGF, and further reversal of bFGF-induced resistance to CPT-11. Our results suggest that peptide P7 may have therapeutic potential in CRC as a sensitizer to chemotherapeutic agents by targeting bFGF.

Anticancer molecules targeting fibroblast growth factor receptors

The fibroblast growth factor receptor (FGFR) family includes four highly conserved receptor tyrosine kinases: FGFR1-4. Upon ligand binding, FGFRs activate an array of downstream signaling pathways, such as the mitogen activated protein kinase (MAPK) and the phosphoinositide-3-kinase (PI3K)/Akt pathways. These FGFR cascades play crucial roles in tumor cell proliferation, angiogenesis, migration, and survival. The combination of knockdown studies and pharmaceutical inhibition in preclinical models demonstrates that FGFRs are attractive targets for therapeutic intervention in cancer. Multiple FGFR inhibitors with various structural skeletons have been designed, synthesized, and evaluated. Reviews on FGFRs have recently focused on FGFR signaling, pathophysiology, and functions in cancer or other diseases. In this article, we review recent advances in structure-activity relationships (SAR) of FGFR inhibitors, as well as the FGFR-targeting drug design strategies currently employed in targeting deregulated FGFRs by antibodies and small molecule inhibitors.

The FGF2-binding peptide P7 inhibits melanoma growth in vitro and in vivo

PURPOSE

Melanoma is a malignant tumor and causes majority of deaths related to skin cancer. Fibroblast growth factor 2 (FGF2) greatly contributes to melanoma growth and progress. In this paper, we attempt to evaluate the therapeutic potential of FGF2-binding peptide (named P7) using as a potent FGF2 antagonist via exploration of its antitumor effect on melanoma in vitro and in vivo.

METHODS

Cell viability was measured by WST-1. Cell cycle progression was determined by propidium iodide staining and flow cytometry. Western blotting was carried out to detect the activation of Erk1/2, P38, Akt, and MEK, and the expression of apoptosis-associated proteins. The influence of P7 on FGF2 internalization was assessed by separation of nuclear and cytoplasmic protein fractions followed by Western blotting. Female C57BL/6 mice bearing xenograft melanoma were established and used to evaluate the antitumor effect of P7 in vivo.

RESULTS

In this study, we first proved that P7 peptides significantly inhibited proliferation of FGF2-induced melanoma cell line B16-F10. Further investigations revealed that the mechanisms of P7 peptides inhibiting cell proliferation of melanoma cells stimulated with FGF2 in vitro involved cell cycle arrest at the G0/G1 phase, blockade of the activation of Erk1/2, P38, and Akt cascades, and inhibition of FGF2 internalization. Finally, treatment of P7 peptides in a murine melanoma model resulted in significant inhibition of tumor growth and angiogenesis in vivo, which was associated with blockade of mitogen-activated protein kinase signal activation, and suppression of the expressions of anti-apoptotic Bcl-2 protein and angiogenic factor in the melanoma tumors.

CONCLUSIONS

The FGF2-binding peptide with potent antiproliferation and anti-angiogenic activity may have therapeutic potential in melanoma.

P7 peptides suppress the proliferation of K562 cells induced by basic fibroblast growth factor

Although it has been known that basic fibroblast growth factor (bFGF) is involved in tumor progression, few studies addressed the role of bFGF in hematopoietic system malignancies including chronic myeloid leukemia (CML). An elevated level of bFGF was recently found in CML patients, and bFGF was considered to play an important role in stimulating the growth of leukemia cells. Suppression of the mitogenic activity of bFGF may contribute to CML therapy. We have previously obtained a novel bFGF-binding peptide (named P7) with strong inhibitory activity against bFGF-induced cell proliferation. In this study, we investigated the effects of P7 on the proliferation of K562 cells derived from CML. The results demonstrated that P7 inhibited bFGF-stimulated proliferation, arrested the cell cycle at the G0/G1 phase, repressed the activation of MAP kinase, reversed the effects of bFGF on cell membrane ultrastructure, and caused significant changes in the expression of proteins related to proliferation. Our results suggested that the bFGF-binding peptide may have a potential antitumor effect on CML from the point of view of targeting bFGF.

Roles of fibroblast growth factor receptors in carcinogenesis

The fibroblast growth factor receptors (FGFR) play essential roles both during development and in the adult. Upon ligand binding, FGFRs induce intracellular signaling networks that tightly regulate key biological processes, such as cell proliferation, survival, migration, and differentiation. Deregulation of FGFR signaling can thus alter tissue homeostasis and has been associated with several developmental syndromes as well as with many types of cancer. In human cancer, FGFRs have been found to be deregulated by multiple mechanisms, including aberrant expression, mutations, chromosomal rearrangements, and amplifications. In this review, we will give an overview of the main FGFR alterations described in human cancer to date and discuss their contribution to cancer progression.