Evaluation of clinical efficacy and tolerability of intravenous high dose thymopentin in advanced melanoma patients

Peptide nano-blanket impedes fibroblasts activation and subsequent formation of pre-metastatic niche

There is evidence to suggest that the primary tumor induces the formation of a pre-metastatic niche in distal organs by stimulating the production of pro-metastatic factors. Given the fundamental role of the pre-metastatic niche in the development of metastases, interruption of its formation would be a promising strategy to take early action against tumor metastasis. Here we report an enzyme-activated assembled peptide FR17 that can serve as a “flame-retarding blanket” in the pre-metastatic niche specifically to extinguish the “fire” of tumor-supportive microenvironment adaption. We show that the in-situ assembled peptide nano-blanket inhibits fibroblasts activation, suppressing the remodeling of the metastasis-supportive host stromal tissue, and reversing vascular destabilization and angiogenesis. Furthermore, we demonstrate that the nano-blanket prevents the recruitment of myeloid cells to the pre-metastatic niche, regulating the immune-suppressive microenvironment. We show that FR17 administration effectively inhibits the formation of the pulmonary pre-metastatic niche and postoperative metastasis, offering a therapeutic strategy against pre-metastatic niche formation.

Primary tumors “spread the spark” by establishing a pre-metastatic niche. Here the authors develop an in-situ assembled peptide FR17 to serve as a “flame-retarding blanket” to extinguish the “fire” of the pre-metastatic microenvironment.

Thymopentin-Mediated Inhibition of Cancer Stem Cell Stemness Enhances the Cytotoxic Effect of Oxaliplatin on Colon Cancer Cells

Thymopentin (TP5) is an immunomodulatory pentapeptide that has been widely used in malignancy patients with immunodeficiency due to radiotherapy and chemotherapy. Here, we propose that TP5 directly inhibits the stemness of colon cancer cells HCT116 and therefore enhances the cytotoxicity of oxaliplatin (OXA) in HCT116 cells. In the absence of serum, TP5 was able to induce cancer stemness reduction in cultured HCT116 cells and significantly reduced stemness-related signals, such as the expression of surface molecular markers (CD133, CD44 and CD24) and stemness-related genes (ALDH1, SOX2, Oct-4 and Nanog), and resulted in altered Wnt/β-catenin signaling. Acetylcholine receptors (AchRs) are implicated in this process. OXA is a common chemotherapeutic agent with therapeutic effects in various cancers. Although TP5 had no direct effect on the proliferation of HCT116, this pentapeptide significantly increased the sensitivity of HCT116 to OXA, where the effect of TP5 on the stemness of colon cancer cells through stimulation of AchRs may contribute to this process. Our results provide a promising strategy for increasing the sensitivity of colon cancer cells to chemotherapeutic agents by incorporating immunomodulatory peptides.

Thymax, a gross thymic extract, exerts cell cycle arrest and apoptosis in Ehrlich ascites carcinoma in vivo

Thymax is a gross thymic extract that has been shown to induce apoptosis in vitro for human breast cancer cells. Here we examine Thymax's ability to induce apoptosis in animals bearing Ehrlich ascites carcinoma (EAC). Thymax was administered six days/week orally to mice (5.45 mg/kg body weight) beginning either 14 days prior to EAC inoculation or 9 days post inoculation; treatment continued for 30 days post inoculation. Pretreatment of mice with Thymax markedly delayed tumor growth and reduced tumor incidence by 38.9%, and tumor volumes relative to untreated controls were suppressed by 90.5% and 55.0% for pre- and post-inoculation groups, respectively. Treatment with Thymax inhibited cellular proliferation by decreasing the expression of tumor markers Ki-67, PCNA, and Cyclin D1 in cancer cells and increasing the expression of p21 and p27. This was associated with the ability of Thymax to arrest the cell cycle of EAC cells in the G0/G1 phase and to induce apoptosis, as indicated by a significant increase in the sub-G1 phase's percentage of hypodiploid cells and further affirmed by DNA fragmentation and Annexin V/propidium iodide staining. In addition, Thymax exerted its apoptotic effect in EAC cancer cells through a mitochondrial-dependent pathway, as evidenced by an increased Bax/Bcl-2 ratio, up-regulation of p53 expression, and activation of caspase-3. We conclude that Thymax supplementation enhances tumor cell demise by arresting the cell cycle and inducing apoptosis. These data suggest that Thymax could be a new adjuvant for breast cancer treatment.

Development of a Highly Efficient Hybrid Peptide That Increases Immunomodulatory Activity Via the TLR4-Mediated Nuclear Factor-κB Signaling Pathway

Immunity is a defensive response that fights disease by identifying and destroying harmful substances or microbiological toxins. Several factors, including work-related stress, pollution, and immunosuppressive agents, contribute to low immunity and poor health. Native peptides, a new class of immunoregulatory agents, have the potential for treating immunodeficiencies, malignancies, and infections. However, the potential cytotoxicity and low immunoregulatory activity and stability of native peptides have prevented their development. Therefore, we designed three hybrid peptides (LTA_a, LTA_b, and LTA_c) by combining a characteristic fragment of LL-37 with an active Tα1 center that included Tα1 (17-24), Tα1 (20-25), and Tα1 (20-27). The best hybrid peptide (LTA_a), according to molecule docking and in vitro experiments, had improved immunoregulatory activity and stability with minimal cytotoxicity. We investigated the immunoregulatory effects and mechanisms of LTA_a using a cyclophosphamide-immunosuppressed murine model. LTA_a effectively reversed immunosuppression by enhancing immune organ development, activating peritoneal macrophage phagocytosis, regulating T lymphocyte subsets, and increasing cytokine (tumor necrosis factor-alpha, interleukin-6, and interleukin-1β) and immunoglobulin (IgA, IgG, and IgM) contents. The immunomodulatory effects of LTA_a may be associated with binding to the TLR4/MD-2 complex and activation of the NF-κB signaling pathway. Therefore, LTA_a could be an effective therapeutic agent for improving immune function.

Thymopentin nanoparticles engineered with high loading efficiency, improved pharmacokinetic properties, and enhanced immunostimulating effect using soybean phospholipid and PHBHHx polymer

Formulation of protein and peptide drugs with sustained release properties is crucial to enhance their therapeutic effect and minimize administration frequency. In this study, immunomodulating polymeric systems were designed by manufacturing PHBHHx nanoparticles (NPs) containing thymopentin (TP5). The release profile of the drug was studied over a period of 7 days. The PHBHHx NPs containing TP5-phospholipid (PLC) complex (TP5-PLC) displayed a spherical shape with a mean size, zeta potential, and encapsulation efficiency of 238.9 nm, -32.0 mV, and 72.81%, respectively. The cytotoxicity results showed the PHBHHx NPs had a relatively low toxicity in vitro. TP5 entrapped in the NPs could hardly release in vitro, while the NPs had longer than 7 days release duration after a single subcutaneous injection in Wistar rats. The immunodepression rat model was built to evaluate the immunomodulating effects of TP5-PLC-NPs in vivo. The results of T-lymphocyte subsets (CD3(+), CD4(+), CD8(+), and CD4(+)/CD8(+) ratio) analysis and superoxide dismutase (SOD) values suggested that TP5-PLC-NPs had stronger immunoregulation effects than TP5 solution. In conclusion, an applicable approach to markedly enhancing the loading of a water-soluble peptide into a hydrophobic polymer matrix has been introduced. Thus, TP5-PLC-NPs are promising nanomedicine systems for sustained release effects of TP5.

The novel role of thymopentin in induction of maturation of bone marrow dendritic cells (BMDCs)

Thymopentin is an immune-modulating peptide that can stimulate cellular immune responses and has been used in many immune handicapped cases [1]. However, despite documented reports proving its efficacy in immunoregulation, there have been no reports, as yet, concerning its impact on the maturation and function of dendritic cells (DCs). In this study, we analyzed the effects of thymopentin on the detailed regulation of maturation of murine bone-marrow-derived DCs (BMDCs). The phenotypic and structural maturation of BMDCs was confirmed by transmission electron microscopy (TEM) and flow cytometry (FCM). The functional maturation was confirmed by an acid phosphatase (ACP) activity test, FITC-dextran bio-assay, test of 5,6-carboxyfluorescein diacetate succinimidyl ester (CFSE), labeled CD4(+)T cell proliferation and enzyme-linked immunosorbent assay (ELISA). We determined that thymopentin up-regulated the expression of CD40, CD80, CD86, CD83, and MHC II molecules on BMDCs, down-regulated phagocytosis of BMDCs, increased BMDCs driven CD4(+)T cell proliferation, and enhanced BMDC production of IL-12 and TNF-α. Therefore, we concluded that thymopentin highly induces BMDC maturation and intensifies DC/T-cell pathways. These data also provide direct evidence and rationale concerning the potential clinical use of thymopentin in various immune handicapped cases and suggest that thymopentin should be considered as a potent adjuvant for DC-based vaccines.

The in vivo immunomodulatory and synergistic anti-tumor activity of thymosin α1-thymopentin fusion peptide and its binding to TLR2

In the present study, the immunomodulatory and synergistic anti-tumor activity of thymosin α1-thymopentin fusion peptide (Tα1-TP5) was investigated in vivo. In addition, the potential receptor of Tα1-TP5 was investigated by surface plasmon resonance (SPR) binding studies. It was found that Tα1-TP5 (305 μg/kg) alleviated immunosuppression induced by hydrocortisone (HC). Tα1-TP5 (305 μg/kg) combined with cyclophosphamide (CY) had a better tumor growth inhibitory effect than CY alone. Furthermore, Tα1-TP5 had a higher affinity (KD=6.84 μmol/L) to toll-like receptor 2 (TLR2) than Tα1 (K(D)=35.4 μmol/L), but its affinity was not significantly different from that of TP5. The results of our present work indicate that Tα1-TP5 can possibly be developed as a new immunomodulatory agent.

[Complementary medicine in oncology]

In cancer therapy vastly different kinds of treatment regimens, but as a rule scientifically validated and reviewed, play a central role dependent on the tumor entity. Besides the options of schoolbook medicine complementary, alternative and supportive treatment options are becoming more frequently used in routine clinical practice. Numerous concepts and agents, partly verified in studies and partly based on empirical experiences are being applied. It is our intention to give a survey of the most common agents and concepts and to point out the risks and capabilities.

Thymopentin (TP5), an immunomodulatory peptide, suppresses proliferation and induces differentiation in HL-60 cells

Thymopentin (Arg-Lys-Asp-Val-Tyr, TP5) has shown immuno-regulatory activities in humans. In the present study, we investigated the effects of TP5 on the proliferation and differentiation of a human promyelocyte leukemia cell line, HL-60. It is noteworthy that TP5 displayed concentration-dependent inhibitory effects on the proliferation and colony formation of HL-60 cells. Furthermore, the decrease or even disappearance of AgNORs from nucleoli was observed in HL-60 cells after the treatment with TP5. The suppression induced by TP5 was accompanied by an accumulation of cell cycle in the G0/G1 phase. Moreover, TP5 significantly increased the NBT-reduction activity of HL-60 cells. Cytofluorometric and morphologic analysis indicated that TP5 had induced differentiation along the granulocytes lineage in HL-60 cells. d-tubocurarine (TUB) significantly antagonized the inhibitory effects induced by TP5, whereas atropine did not exhibit such effect. All the results indicated that TP5 was able to significantly inhibit proliferation and induce differentiation in HL-60 cells. Our observations also implied that TP5 not only acted as an immunomodulatory factor in cancer chemotherapy, but is also a potential chemotherapeutic agent in the human leukemia therapy.

Meta-analysis: the adjuvant role of thymopentin on immunological response to hepatitis B virus vaccine in end-stage renal disease

BACKGROUND

It has been calculated that 30-40% of dialysis patients fail to produce antibodies to HBsAg antigen after vaccination towards hepatitis B virus. Several authors have reported on the benefit of thymopentin (TP5) as adjuvant to vaccine against hepatitis B virus in patients receiving regular dialysis. However, consistent information on this issue is still lacking.

AIMS

To evaluate efficacy and safety of thymopentin as adjuvant to hepatitis B vaccine in dialysis patients by performing a systematic review with a meta-analysis of clinical trials.

METHODS

We used the random effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses.

RESULTS

We identified 11 studies involving 272 unique patients with end-stage renal disease. Only prospective, controlled trials were included. Pooling of study results did not show a significant increase in seroresponse rate among study (thymopentin plus hepatitis B virus vaccine) vs. control (hepatitis B virus vaccine alone) patients; the pooled odds ratio of failure to respond to hepatitis B virus vaccine was 0.677 (95% confidence intervals: 0.285-1.605); no heterogeneity was found (P = 0.0001). Thymopentin significantly improved the seroresponse rate in the subgroup of trials based on greater thymopentin doses (OR: 0.184; 95% CI: 0.085-0.398).

CONCLUSIONS

Our meta-analysis showed that thymopentin significantly improved the seroresponse rate towards hepatitis B vaccine only in dialysis patients treated with higher thymopentin doses. The limited number of patients precluded definitive conclusions.

Thymic hormones in cancer diagnostics and treatment

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.

Review of thymic hormones in cancer diagnosis and treatment

The thymus is an endocrine organ. A unified, physiological concept of humoral regulations of the immune response has emerged in the last three decades. The thymus is the major site of production of immunocompetent T lymphocytes from their hematopoietic stem cells. This complex process required direct cell to cell, receptor based interactions, as well as in situ paracrine information via the numerous cytokines and thymic hormones produced by the cells of thymic microenvironment. Thymic hormones induce in situ T-cell marker differentiation, expression and functions. These polypeptide hormones have also been shown by means of immunocytochemistry to localize in the reticulo-epithelial (RE) cells of the thymic cellular microenvironment. Due to the great complexity of the intrathymic maturation sequence of T lymphocytes and the diverse immunophenotypically unique subpopulations of T lymphocytes, it is quite unlikely that a single thymic humoral factor could control all of the molecular steps and cell populations involved. It is much more likely that an extremely rich and diverse, but genetically determined, milieu is present within the thymus, and that thus the control of intrathymic T lymphocyte maturation and the functional maturation of T cells involves the orchestral interaction of various thymic-specific factors and other molecules during the differentiation process. Thymosin fraction 5 and its constituent peptides influence several properties of lymphocytes including cyclic nucleotide levels, migration inhibitory factor production, T-dependent antibody production, as well as the expression of various cell surface maturation/differentiation markers. Recently, derivatives of thymic hormones, mostly of thymosins, have been detected as products of neoplastically transformed cells and employed in the early diagnosis of neoplasms. In clinical trials, thymic hormones strengthen the effects of immunomodulators in immunodeficiencies, autoimmune diseases, and neoplastic malignancies. Combined chemo-immunotherapeutical anti-cancer treatment seems to be more efficacious than chemotherapy alone, and the significant hematopoietic toxicity associated with most chemotherapeutical clinical trials can be reduced significantly by the addition of immunotherapy.