Bioparameter-directed nanoformulations as MRI CAs enable the specific visualization of hypoxic tumour.

A malignant tumour has hypoxic cells of varying degrees. The more severe the hypoxic degree, the more difficult the prognosis of the tumour and the higher the recurrence rate. Therefore, tumour hypoxia imaging is crucial. Magnetic resonance imaging (MRI) shows its strength in high resolution, depth of penetration and noninvasiveness. However, it needs more excellent contrast agents (CAs) to combat the complex tumour microenvironment (TME) and increased targeting of tumours to enhance clinical safety. Many research studies have focused on developing hypoxia-responsive MRI CAs that take advantage of the unique characteristics of hypoxic tumours. The low oxygen pressure, acidic TME, and up-regulated redox molecule levels found in hypoxic tumours serve as biological stimuli for nanoformulations that can accurately image the hypoxic region. This review highlights the importance of developing bioparameter-directed nanoformulations as MRI CAs for accurate tumour diagnosis. The design strategies and mechanisms of tumour-hypoxia imaging with nanoformulations are exemplified, with a focus on pH-responsiveness, redox-responsiveness, and p(O2)-responsiveness. The promising future of bioparameter-responsive nanoformulations for accurate tumour diagnosis and personalised cancer treatment is discussed.

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.

A short peptide derived from the gN helix domain of FGF8b suppresses the growth of human prostate cancer cells.

Previous studies have demonstrated that fibroblast growth factor 8b (FGF8b) is up-regulated in a large proportion of prostate cancer patients and that it plays a key role in prostate carcinogenesis. In this study, we designed and synthesized a gN helix domain derived short peptide (termed 8b-13) based on the analysis of the FGF8b-FGFR structure. The synthetic peptides inhibited the proliferation of prostate cancer cell lines, including PC-3 and DU-145 cells. Further investigations indicated that 8b-13 arrested the cell cycle at the G0/G1 phase, reduced the activation of the Erk1/2, P38, and Akt cascades, and down-regulated the expression of G1/S-specific cyclinD1. The suppression of DNA synthesis and the G1 to S phase transition due to the expression of proteins related to proliferation and cell cycle progression may contribute to the inhibitory effect of 8b-13 peptides on cellular proliferation. Our results not only suggest that 8b-13 exerts an antitumor effect in prostate cancer but also confirm the essential role of the gN helix domain in mediating the activity of FGF8b.

A novel bFGF antagonist peptide inhibits breast cancer cell growth.

Breast cancer is the most common type of cancer in women worldwide. Elevated expression of the basic fibroblast growth factor (bFGF) has been found in patients suffering from breast cancer. We previously obtained a high-affinity bFGF-binding peptide (named P7) from a phage-display random heptapeptide library. In this study, we show that P7 peptides significantly inhibits the proliferation of the bFGF-stimulated MDA-MB-231 breast cancer cell line. Additional experiments revealed that the mechanisms of the P7 peptide inhibition of the cell proliferation of breast cancer cells stimulated with bFGF in vitro involved cell cycle arrest at the G0/G1 phase, blockade of the activation of Erk and P38 cascades and the upregulation of the expression of the growth inhibitor, proliferation-associated protein 2G4. These results suggest that the bFGF-binding peptide may have therapeutic potential in breast cancer therapy.

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.