RESUMEN
Background: Cardiac troponin-T (TNNT2) is exclusively present in cardiac muscle. Measurement of TNNT2 is used for diagnosing acute coronary syndrome. However, its expression may not be limited in myocardium. This study aimed at evaluating the expression of TNNT2 in neoplastic tissues. Methods and Results: We used paraffin-embedded blocks of 68 patients with lung cancer (age, 68 ± 11 years old; early-stage, 33; advance-stage, 35) at Miyazaki University Hospital, Japan between January 1, 2017, and March 31, 2019. We stained the slide sections with primary monoclonal antibody against TNNT2 protein, and assessed the frequency of positive staining, and its association with pathological severity. In addition, we examined whether TNNT2 gene is detected in lung cancer tissues of four patients using reverse transcription-polymerase chain reaction. Immunoreactivity for TNNT2 protein was present in the cytoplasm and nucleus of lung cancer cells. The frequency was 37% (25 of 68) in all patients and was irrespective of histologic type (six of 13, squamous cell carcinoma; 18 of 50, adenocarcinoma; 0 of 4, neuroendocrine cell carcinoma; 1 of 1, large cell carcinoma). The prevalence increased with pathological staging [9% (3 of 33) at early-stage (Stage 0-I); 63% (22 of 35) at advance-stage (Stage II-IV and recurrence)]. In addition, frequency of positive staining for TNNT2 increased with pleural (χ2 = 5.877, P = 0.015) and vascular (χ2 = 2.449, P = 0.118) invasions but decreased with lymphatic invasion (χ2 = 3.288, P = 0.070) in specimens performed surgical resection. Furthermore, TNNT2 mRNA was detected in the resected squamous cell carcinoma and adenocarcinoma tissues. Conclusions: Our data suggest the aberrant expression of TNNT2 in lung cancer and its prevalence increases with pathological severity.
RESUMEN
Human adrenomedullin (hAM) is a hypotensive peptide hormone that exerts powerful anti-inflammatory effects. However, treatment required continuous administration of hAM, as the half-life of native hAM is quite short in blood. To resolve this problem, we designed two kinds of human IgG1 Fc fusion proteins containing either full-length hAM (IgG1-AM) or hAM residues 6-52 [IgG1-AM (6-52)]. A DNA construct was constructed by connecting DNA sequences encoding hAM and the IgG1 Fc region with a DNA sequence encoding a (GGGGS)3 linker. The molecular weights of IgG1-AM and IgG1-AM (6-52) were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography. By protein sequencing, the N-terminal sequence of both recombinant AM-Fc fusions showed the expected human IgG1 sequence. Sufficient concentrations of both AM-Fc fusions were observed in blood 2 days after a single subcutaneous administration. IgG1-AM and IgG1-AM (6-52) stimulated cAMP production in human embryonic kidney-293 cells stably expressing the AM1 receptor. The activity of IgG1-AM (6-52) was higher than that of IgG1-AM. Treatment with IgG1-AM (6-52) inhibited blood pressure increase in spontaneously hypertensive rats. In addition, IgG1-AM (6-52) reduced total inflammation scores in the dextran sulfate sodium colitis model. Therefore, AM-IgG1 Fc fusions represent potential novel therapeutic agents.