BackgroundThe ras genes play an important role in the development and progression of human tumours. Neutralizing Ras proteins in the cytoplasm could be an effective approach to blocking ras signalling. In this study, we prepared anti-p21Ras single chain fragment variable antibody (scFv) and investigated its immunoreactivity with human tumours.MethodsThe coding sequences of H-ras, K-ras, and N-ras were separately ligated into the vector pET-28a(+). Then, recombinant expressing plasmids were induced by IPTG for p21Ras expression in E. coli. Hybridoma cell lines producing anti-p21Ras monoclonal antibodies were isolated using wildtype p21Ras proteins as immunogens. Anti-p21Ras scFv antibody was prepared from the hybridoma by the phage scFv display method. The immunoreactivity of the anti-p21Ras monoclonal antibody and the scFv antibody was identified by ELISA and immunocytochemistry.ResultsWe prokaryotically expressed wildtype H-p21Ras, K-p21Ras and N-p21Ras and generated the hybridoma cell line KGH-R1, producing anti-p21Ras monoclonal antibodies. It was demonstrated that KGH-R1 monoclonal antibody could recognize wildtype and mutated H-p21Ras, K-p21Ras and N-p21Ras in human tumour cell lines.In all 14 types of primary human cancer tissues tested, the monoclonal antibody presented strong immunoreactivity but showed weak or negative immunoreactivity in the corresponding normal tissues. Subsequently, we prepared anti-p21Ras scFv from hybridoma KGH-R1, which showed the same immunoreactivity as the original monoclonal antibody. Sequence analysis demonstrated that the nucleotides and amino acids of the scFv exhibited an approximately 50 % difference from the anti-p21Ras scFv reported previously.ConclusionsThis study presents a novel anti-p21Ras scFv antibody. Our data suggest that the scFv may be useful for ras signalling blockage and may be a potential therapeutic antibody for ras-derived tumours.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2168-6) contains supplementary material, which is available to authorized users.
Introduction: Pancreatic ductal adenocarcinoma (PDAC) is the most prevalent malignancy of the pancreas, and the incidence of this disease is approximately equivalent to the mortality rate. Immunotherapy has made a remarkable breakthrough in numerous cancers, while its efficacy in PDAC remains limited due to the immunosuppressive microenvironment. Immunotherapy efficacy is highly correlated with the abundance of immune cells, particularly cytotoxic T cells. Therefore, molecular classifier is needed to identify relatively hot tumors that may benefit from immunotherapy. Method: In this study, we carried out a transcriptome analysis of 145 pancreatic tumors to define the underlying immune regulatory mechanism driving the PDAC immunosuppressive microenvironment. The immune subtype was identified by consensus clustering, and the underlying PDAC immune activation mechanism was thoroughly examined using single sample gene set enrichment analysis (ssGSEA). Area under the curve (AUC) of the receiver operating characteristic (ROC) curve was used to assess the accuracy of the molecular classifier in differentiating immunological subgroups of PDAC.5 Result: The protein level of molecular classifier was verified by immunohistochemistry in human PDAC tissue. Immune-hot tumors displayed higher levels of immune cell infiltration and immune checkpoint, in line with enriched immune escape pathways. Hematopoietic cell signal transducer (HCST), a molecular classifier used to differentiate immunological subtypes of PDAC, has shown a substantial link with the expression levels of cytotoxic markers, such as CD8A and CD8B. At the single cell level, we found that HCST was predominantly expressed in CD8T cells. By immunohistochemistry and survival analysis, we further demonstrated the prognostic value of HCST in PDAC. Conclusion: We identified HCST as a molecular classifier to distinguish PDAC immune subtypes, which may be useful for early diagnosis and targeted therapy of PDAC.
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