Detection of Binding of a Synthetic Granzyme B-like Peptide Fluorescent Conjugate within Platelet-like Structures in Cancer-related Peripheral Blood Specimens and Tissue Sections
- 194 Downloads
Platelets and cytotoxic T lymphocytes (CTL) are important whole blood components in peripheral blood. Studies have shown that platelets, from precursor megakaryocytes, are significant factors in cancer prognosis, cancer progression, and metastasis; but a direct platelet-cancer relationship remains unclear. CTL play an essential role in cancer surveillance by inducing cancer cell death with granzyme B. A recent report has shown the presence of binding targets with binding affinity to a synthetic granzyme B-like peptide fluorescent conjugate (GP1R) in different types of cancer cells grown in vitro. It suggests that these binding targets may serve as a “universal-pathologic-biomarker”. It is not known if similar biomarkers may be present in platelets of cancer patients. We show with fluoroscopic images that GP1R can bind to binding targets: 1) within platelets in methanol-fixed whole blood smears of patients with breast cancer and lung cancer, and 2) within platelet-like structures in formalin-fixed-paraffin-embedded (FFPE) nude mouse xenogeneic breast tumor tissues. Samples without cancer-association displayed no discernible GP1R-binding in platelet-like structures. Our data demonstrate for the first time that a similar “universal-pathologic-biomarker” detectable by GP1R-binding is present in circulating platelets of cancer patients. The data depict a co-existence of animal-platelets and human-breast cancer cells, both have a common pathologic biomarker detectable by GP1R, in the tumor growth. The fluoroscopic images indicate a visual direct connection between pathologic platelets and cancer. These preliminary results may lead to developments of novel platelet-based cancer diagnostics and therapeutics and a better understanding of the potential multifunction of GP1R and its relationship to megakaryocytes and PD1.
KeywordsBiomarker Cancer Fluorescence microscopy Granzymes Peptide Platelets
- 1.Matowicka-Karna J et al (2013) Platelets and inflammatory markers in patients with gastric cancer. Clin Dev Immunol vol. 2013, Article ID 401623, 6 pages. doi: 10.1155/2013/401623
- 6.Stravodimou A, Voutsadakis IA (2013) Pretreatment thrombocytosis as a prognostic factor in metastatic breast cancer. Int J Breast Cancer vol. 2013, Article ID 289563, 6 pages. doi: 10.1155/2013/289563
- 13.Assoian RK et al (1983) Transforming growth factor-beta in human platelets. Identification of a major storage site, purification, and characterization. J Biol Chem 58:7155–7160Google Scholar