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Background/Objective: Prothymosin alpha (proTα) is a ubiquitous polypeptide first isolated by Haritos in 1984, whose role still remains partly elusive. We know that proTα acts both, intracellularly, as an anti-apoptotic and proliferation mediator, and extracellularly, as a biologic response modifier mediating immune responses similarly to molecules termed as “alarmins”. Our research team pioneered the elucidation of the mechanisms underlying the observed activities of proTα. Results: We were the first to demonstrate that proTα levels increase during normal and abnormal cell proliferation. We showed that proTα acts pleiotropically, inducing immunomodulatory effects on immune cell populations. We revealed that the immunoreactive region of proTα is the carboxyterminal decapeptide proTα(100-109) and both molecules stimulate innate immune responses, signaling through Toll-like receptors (TLRs), specifically TLR-4. We reported that proTα and proTα(100-109) bind on the surface of human neutrophils on sites involving TLR-4, and cell activation is complemented by cytoplasmic calcium ion influx. Further, we showed that proTα and proTα(100-109) act as adjuvants upstream of lymphocyte stimulation and, in the presence of antigen, promote the expansion of antigen-reactive effectors. Most recently, we reported that proTα(100-109) may accumulate in experimentally inflamed sites and can serve as a surrogate biomarker in severe bacterial infections, proposing that extracellular release of proTα or proTα(100- 109) alerts the immune system during conditions of danger. Conclusion: We, therefore, suggest that proTα, and likely proTα(100-109), act as alarmins, being important immune mediators as well as biomarkers, and could eventually become targets for new therapeutic/diagnostic approaches in immune-related diseases like cancer, inflammation, and sepsis.

The reaction of the C‐functionalized cyclam chelating agent 1,4,8,11‐tetraazacyclotetradecane‐6‐carboxylic acid (1) with CuCl2generated a stable and neutral complex 2, which was characterized by elemental analysis, UV/Vis and IR spectroscopy, electrospray ionization mass spectrometry (ESI‐MS), EPR spectroscopy and X‐ray crystallography. The secondary amine groups of 1were protected to generate 3, which was further conjugated with the bombesin (BN) derivative H2N‐(Ornithine)3‐BN(2–14) by a solid phase peptide synthesis method. After cleavage from the resin and deprotection, the resulting product 5was obtained and characterized with ESI‐MS and NMR spectroscopy, and was subsequently complexed under mild conditions with CuCl2to generate complex 6in high yield. Complex 6was characterized with UV/Vis spectroscopy, ESI‐MS and EPR spectroscopy. The stability of complexes 2and 6was tested against cysteine, histidine and glutathione, and both complexes were found to be stable. The cyclam BN conjugate 5and its CuIIcomplex 6were suitable for targeting the gastrin releasing peptide receptors (GRPrs) that are over expressed on PC‐3 cells. Both 5and 6showed high binding affinity to GRPrs during in vitro cell assays with human PC‐3 prostate cancer cells. The half maximal inhibitory concentration (IC50) values observed for 5and 6(0.30 ± 0.03 and 0.33 ± 0.03 nM, respectively) were similar to that of the [Tyr]4‐BN peptide (0.45 ± 0.04 nM), which was used as standard.