title: 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.
abstract: 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.
authors.affiliation: BioJENC, Louisiana Emerging Technology Center, Baton Rouge, Louisiana, 340 East Parker Blvd., Baton Rouge, LA, 70803-0106, USA, jlo769@gmail.com.
authors.forename: Wai Chun Jennifer
authors.initials: WC
authors.lastname: Lo
authors.forename: Donald Gene
authors.initials: DG
authors.lastname: Luther
mesh_terms: D000818:Animals; D001665:Binding Sites; D045744:Cell Line, Tumor; D005453:Fluorescence; D053804:Granzymes / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D016612:Paraffin Embedding; D010455:Peptides / Q000032:analysis* / Q000138:chemical synthesis / Q000378:metabolism; D011487:Protein Conformation; D016707:Tissue Fixation
chemical_list: D010455:Peptides; D053804:Granzymes
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