Thymic hormones in cancer diagnostics and treatment

Abstract

The thymus is an endocrine organ. A unified, physiological concept of humoral regulation of the immune response emerged in the last three decades. The thymus is the primary major site of production of immunocompetent T-lymphocytes from their haematopoietic stem cells. The thymus provides a superior humoral microenvironment for the development of immunocompetent T-lymphocytes. Although yolk sac derived pre-T stem cells enter the thymus using a homing receptor, the immigration process requires also secretion of a peptide, called thymotaxin by the cells of the reticulo-epithelial (RE) network. This complex process requires direct cell to cell, receptor based interactions, as well as in situ paracrine information via the numerous cytokines and thymic hormones produced by the RE cells of thymic microenvironment. Thymic hormones induce in situ T-lymphocyte marker differentiation, expression and functions. These polypeptide hormones have also been shown by means of immunocytochemistry to localise in the RE cells of the thymic cellular microenvironment. Based on the complexity of the intrathymic maturation sequence of T-lymphocytes and the increasing numbers of T-lymphocyte subpopulations that are being identified, it would be surprising if a single thymic humoral factor could control all of the molecular steps and cell populations involved. Rather, it would appear that the control of intrathymic T-lymphocyte maturation and functional maturation involves a complex number of thymic-specific factors and other molecules that rigidly control the intermediary steps in the differentiation process. Thymosin fraction 5 (TF5) and its component polypeptides influence a variety of lymphocyte properties including cyclic nucleotide levels, migration inhibitory factor production, T-dependent antibody production and expression of certain surface maturation/differentiation markers. Recently, thymic hormones, mostly thymosins have been employed not only in neoplasms' early detection but also in clinical trials to strengthen the effects of immunomodulators in immunodeficiencies, autoimmune diseases and neoplastic malignancies. Combined chemoimmunotherapeutical antineoplastic treatment seems to be useful. Generally, haematopoietic toxicity of every chemotherapeutical clinical trial can be reduced significantly by the immunotherapy, compared to 50% in patients treated with chemotherapy alone.

Thymostimulin in advanced hepatocellular carcinoma: A phase II trial

“…Moreover, virtually no side-effects were apparent. Isolated from calf thymus, thymostimulin is a standardized low-molecular protein fraction including thymosin-α1 and thymic humoral factor [ 7 , 8 ]. It has been shown to induce the proliferation and differentiation of T-lymphocytes and to stimulate the release of interferons and interleukin-2 [ 9 ].…”

Thymosin plus cisplatin with vinorelbine or gemcitabine for non‐small cell lung cancer: A systematic review and meta‐analysis of randomized controlled trials

“…It can also regulate T lymphocyte subsets, enhance immune function, and play an important role in the support of cancer treatment 8 . Thymosin alpha 1(Ta1) and thymopentin are the main active ingredients of thymosin.Ta1 is composed of 28 amino acids generated from prothymosin, whose DNA replication and transcription in the epithelial cells of the thymus is enzymatic 9 . Thymopentin was first isolated from calf thymus.…”

“…8 Thymosin alpha 1(Ta1) and thymopentin are the main active ingredients of thymosin.Ta1 is composed of 28 amino acids generated from prothymosin, whose DNA replication and transcription in the epithelial cells of the thymus is enzymatic. 9 Thymopentin was first isolated from calf thymus. It is a fragment of a large peptide and consists of 49 amino acids.…”

Ανάπτυξη Ανοσοχημικών Τεχνικών Για Την Αξιολόγηση Της Θυμοσίνης Β15 Ως Πιθανού Καρκινικού Δείκτη Στον Καρκίνο Του Μαστού

“…Σήμερα, τα πεπτίδια αυτά (θυμοσίνη αΐ και προθυμοσίνη) έχουν χρησιμοποιηθεί όχι μόνο σε κλινικές δοκιμές για την ενίσχυση της επίδρασης ανοσορυθμιστών σε ανοσοανεπάρκειες, αυτοάνοσα νοσήματα και νεοπλαστικές κακοήθειες (Bodey, 2001), αλλά και στην έγκαιρη ανίχνευση νεοπλασιών, καθώς τόσο η Tal όσο και η ProTa έχουν συσχετιστεί άμεσα με κακοήθειες.…”