Secretion of enteric α-defensin 5 into bloodstream by colon tumors

The screening for enteric α-defensin was performed in the blood serum of oncology patients and healthy donors. Enteric α-defensin was not detected in all serum samples from five healthy donors, while serum samples from two of the five oncology patients had the processed form of this protein. The acquired results allow us to suggest the possibility of the serological diagnostics of large intestinal tumors in high-risk groups.     

Mesenchymal stromal cells alone or expressing interferon-β suppress pancreatic tumors in vivo,an effect countered by anti-inflammatory treatment

Background aimsBecause of the inflammatory nature and extensive stromal compartment in pancreatic tumors, we investigated the role of mesenchymal stromal cells (MSC) to engraft selectively in pancreatic carcinomas and serve as anti-tumor drug delivery vehicles to control pancreatic cancer progression.MethodsHuman pancreatic carcinoma cells, PANC-1, expressing renilla luciferase were orthotopically implanted into SCID mice and allowed to develop for 10 days. Firefly luciferase-transduced MSC or MSC expressing interferon (IFN)-β were then injected intraperitoneally weekly for 3 weeks. Mice were monitored by bioluminescent imaging for expression of renilla (PANC-1) and firefly (MSC) luciferase.ResultsMSC selectively homed to sites of primary and metastatic pancreatic tumors and inhibited tumor growth (P = 0.032). The production of IFN-β within the tumor site by MSC–IFN-β further suppressed tumor growth (P = 0.0000083). Prior studies indicated that MSC home to sites of inflammation; therefore, we sought to alter the tumor microenvironment through treatment with a potent anti-inflammatory agent. After treatment, inflammation-associated mediators were effectively down-regulated, including NFκB, vascular endothelial growth factor (VEGF) and interleukin (IL)-6 as well as chemokines involved in MSC migration (CCL3 and CCL25). Treatment with the anti-inflammatory agent CDDO-Me before and after MSC–IFN-β injections resulted in reduction of MSC in the tumors and reversed the positive effect of tumor inhibition by MSC–IFN-β alone (P = 0.041).ConclusionsThese results suggest that MSC exhibit innate anti-tumor effects against PANC-1 cells and can serve as delivery vehicles for IFN-β for the treatment of pancreatic cancer. However, these beneficial effects may be lost in therapies combining MSC with anti-inflammatory agents.     

Targeting of solid tumors and blood malignancies by antibody-based therapies — EGFR-pathway as an example

A well-coordinated interaction between extracellular signals and intracellular response forms the basis of life within multicellular organisms, with growth factors playing a crucial role in these interactions. Discoveries in recent years have shown that components of the Epidermal Growth Factor (EGF) signaling system have frequently been used by cancer cells to autonomously provide survival and proliferation signals. The main focus of this review is the ErbB epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases including ErbB1/EGFR, ErbB2/HER2/neu, ErbB3/HER3, and ErbB4/HER4 as therapeutic targets. Since the ErbB receptor family regulates cell proliferation through the Ras-mitogen-activated protein kinase (RAS/MAPK) pathway, and cell survival and transformation through the phosphatidylinositol 3-kinase (PI3K/AKT) pathway, pharmacological targeting of these pathways is also discussed. We will also address the clinical studies that have been conducted to evaluate antibody-based therapies mostly on solid tumors and hematologic malignancies.     

γ-Irradiation facilitates the expression of adoptive immunity against established tumors by eliminating suppressor T cells

Summary It was found that sublethal (550 rad) whole-body -irradiation of mice bearing established immunogenic tumors enabled tumor-sensitized spleen cells infused intravenously 1 h later to cause complete tumor regression in all mice. In contrast, -irradiation alone caused only a temporary halt in tumor growth, and immune cells gave practically no therapeutic effect at all. This result was obtained with the SA1 sarcoma, Meth A fibrosarcoma, P815 mastocytoma, and P388 lymphoma. Additional experiments with the Meth A fibrosarcoma revealed that the spleen cells from tumor-immune donors that caused tumor regression in -irradiated recipients were T cells, as evidenced by their functional elimination by treatment with anti-Thy-1.2 antibody and complement. It was shown next that adoptive T-cell-mediated regression of tumors in -irradiated recipients was inhibited by an intravenous infusion of spleen cells from donors with established tumors, but not by spleen cells from normal donors. The spleen cells that suppressed the expression of adoptive immunity were functionally eliminated by treatment with anti-Thy-1.2 antibody and complement. Moreover, they were destroyed by exposing the tumor-bearing donors to 500 rad of -radiation 24 h before harvesting their spleen cells. The results are consistent with the interpretation that -radiation facilitates the expression of adoptive T-cell-mediated immunity against established tumors by eliminating a population of tumor-induced suppressor T cells from the tumor-bearing recipient.Supported by Grants CA-16642 and CA-27794 from the National Cancer Institute, a Grant-in-Aid from R. J. Reynolds Industries, Inc. and Grant RR-05705 from the Division of Research Resources, NIH     

γ-Irradiation facilitates the expression of adoptive immunity against established tumors by eliminating suppressor T cells

It was found that sublethal (550 rad) whole-body gamma-irradiation of mice bearing established immunogenic tumors enabled tumor-sensitized spleen cells infused intravenously 1 h later to cause complete tumor regression in all mice. In contrast, gamma-irradiation alone caused only a temporary halt in tumor growth, and immune cells gave practically no therapeutic effect at all. This result was obtained with the SA1 sarcoma, Meth A fibrosarcoma, P815 mastocytoma, and P388 lymphoma. Additional experiments with the Meth A fibrosarcoma revealed that the spleen cells from tumor-immune donors that caused tumor regression in gamma-irradiated recipients were T cells, as evidenced by their functional elimination by treatment with anti-Thy-1.2 antibody and complement. It was shown next that adoptive T-cell-mediated regression of tumors in gamma-irradiated recipients was inhibited by an intravenous infusion of spleen cells from donors with established tumors, but not by spleen cells from normal donors. The spleen cells that suppressed the expression of adoptive immunity were functionally eliminated by treatment with anti-Thy-1.2 antibody and complement. Moreover, they were destroyed by exposing the tumor-bearing donors to 500 rad of gamma-radiation 24 h before harvesting their spleen cells. The results are consistent with the interpretation that gamma-radiation facilitates the expression of adoptive T-cell-mediated immunity against established tumors by eliminating a population of tumor-induced suppressor T cells from the tumor-bearing recipient.     

Mena, a new available marker in tumors of salivary glands?

Mena (mammalian Ena) is an actin regulatory protein involved in cell motility and adhesion. Based on its potential role in malignant transformation revealed in other organs, we analyzed the Mena expression in normal salivary glands (SG) and salivary tumors. Mena expression was determined in normal SG (n=10) and also benign (n=20) and malignant (n=35) lesions of SG. For the immunohistochemical staining we used the anti-Mena antibody. All normal SG and the benign lesions (10 pleomorphic adenomas, 10 Warthin's tumors) were Mena negative. Salivary duct carcinomas (n=5), carcinomas in pleomorphic adenoma (n=5), acinic cell carcinomas (n=5), squamous cell carcinomas (n=10) and high-grade mucoepidermoid carcinomas (n=2) were positive. The lymphomas (n=5) and low-grade mucoepidermoid carcinomas (n=1) were Mena negative. In one case the lymphoblastic cells stained positive for Mena. Some of the endothelial cells, in the peritumoral vessels, were Mena positive. To the best of our knowledge, this is the first study in the literature about Mena expression in salivary tumors. Our study suggests that Mena protein seems to play a role in malignant transformation and its intensity is correlated with the type and grade of tumor and also with vascular invasion. Its positivity in endothelial cells may suggest its potential role in tumor angiogenesis.     

Synthesis and in vitro evaluation of thiododecaborated α, α- cycloalkylamino acids for the treatment of malignant brain tumors by boron neutron capture therapy

Boron-neutron capture therapy (BNCT) is an attractive technique for cancer treatment. As such, α, α-cycloalkyl amino acids containing thiododecaborate ([B₁₂H₁₁]^2?-S-) units were designed and synthesized as novel boron delivery agents for BNCT. In the present study, new thiododecaborate α, α-cycloalkyl amino acids were synthesized, and biological evaluation of the boron compounds as boron carrier for BNCT was carried out.     

Spontaneous immune responses to sporadic tumors: tumor-promoting, tumor-protective or both?

Cancer cells cannot develop into invasive cancers without interactions with cells and soluble mediators present in the tumor microenvironment. Accumulating evidence indicates that the immune system is a critical determinant of malignant outgrowth; however, the tumor-modulating effects of spontaneous immune responses towards nascent malignancies are rather paradoxical. Both cancer-protective and cancer-promoting features of the immune system have been described. This review will discuss the role of the dynamic inflammatory tumor microenvironment during cancer development and progression, and will focus on the intriguing question: “Do malignancies develop in spite of—or because of—spontaneous immune responses?” Special emphasis will be put on recent progress in our understanding of the immune system’s double-edged sword function during de novo carcinogenesis.     

Virulizin® induces production of IL-17E to enhance antitumor activity by recruitment of eosinophils into tumors

Virulizin has demonstrated strong antitumor efficacy in a variety of human tumor xenograft models including melanoma, pancreatic cancer, breast cancer, ovarian cancer and prostate cancer. Our previous studies have demonstrated that macrophages, NK cells, and cytokines are important in the antitumor mechanism of Virulizin. Virulizin treatment of tumor bearing mice results in the expansion as well as increased activity of monocytes/macrophages and production of cytokines IL-12 and TNFalpha and activation of NK cells. In this study we show that the inflammatory cytokine IL-17E (IL-25) is induced by Virulizin treatment and is part of its antitumor mechanism. IL-17E is a proinflammatory cytokine, which induces a T(H)2 type immune response, associated with eosinophil expansion and infiltration into mucosal tissues. IL-17E was increased in sera of Virulizin-treated mice bearing human melanoma xenografts, compared to saline-treated controls, as shown by 2D gel electrophoresis and ELISA. Treatment of splenocytes in vitro with Virulizin resulted in increased IL-17E mRNA expression, which peaked between 24 and 32 h post-stimulation. Both in vitro and in vivo experiments demonstrated that B cells produced IL-17E in response to Virulizin treatment. Furthermore, Virulizin treatment in vivo resulted in increased blood eosinophilia and eosinophil infiltration into tumors. Finally, injection of recombinant IL-17E showed antitumor activity towards xenografted tumors, which correlated with increased eosinophilia in blood and tumors. Taken together, these results support another antitumor mechanism mediated by Virulizin, through induction of IL-17E by B cells, leading to recruitment of eosinophils into tumors, which may function in parallel with macrophages and NK cells in mediating tumor destruction.     

Escape mechanisms after antiangiogenic treatment, or why are the tumors growing again?

Inhibitors of angiogenesis and radiation induce compensatory changes in the tumor vasculature both during and after cessation of treatment. In numerous preclinical studies, angiogenesis inhibitors were shown to be efficient in the treatment of many pathological conditions, including solid cancers. In most clinical trials, however, this approach turned out to have no significant effect, especially if applied as monotherapy. Recovery of tumors after therapy is a major problem in the management of cancer patients. The mechanisms underlying tumor recovery (or therapy resistance) have not yet been explicitly elucidated. This review deals with the transient switch from sprouting to intussusceptive angiogenesis, which may be an adaptive response of tumor vasculature to cancer therapy that allows the vasculature to maintain its functional properties. Potential candidates for molecular targeting of this angioadaptive mechanism are yet to be elucidated in order to improve the currently poor efficacy of contemporary antiangiogenic therapies.     

Mitochondria: 3-bromopyruvate vs. mitochondria? A small molecule that attacks tumors by targeting their bioenergetic diversity

Enhanced glycolysis, the classic bioenergetic phenotype of cancer cells was described by Otto Warburg approximately 90 years ago. However, the Warburg hypothesis does not necessarily imply mitochondrial dysfunction. The alkyl-halogen, 3-bromopyruvate (3BP), would not be expected to have selective targets for cancer therapy due to its high potential reactivity toward many SH side groups. Contrary to predictions, 3BP interferes with glycolysis and oxidative phosphorylation in cancer cells without side effects in normal tissues. The mitochondrial hexokinase II has been claimed as the main target. This “Organelle in focus” article presents a historical view of the use of 3BP in biochemistry and its effects on ATP-producing pathways of cancer cells. I will discuss how the alkylated enzymes contribute to the cooperative collapse of mitochondria and apoptosis. Perspectives for targeting 3BP to bioenergetics enzymes for cancer treatment will be considered.     

Is xenodontine snake reproduction shaped by ancestry,more than by ecology?

One of the current challenges of evolutionary ecology is to understand the effects of phylogenetic history (PH) and/or ecological factors (EF) on the life‐history traits of the species. Here, the effects of environment and phylogeny are tested for the first time on the reproductive biology of South American xenodontine snakes. We studied 60% of the tribes of this endemic and most representative clade in a temperate region of South America. A comparative method (canonical phylogenetic ordination—CPO) was used to find the relative contributions of EF and PH upon life‐history aspects of snakes, comparing the reproductive mode, mean fecundity, reproductive potential, and frequency of nearly 1,000 specimens. CPO analysis showed that PH or ancestry explained most of the variation in reproduction, whereas EF explained little of this variation. The reproductive traits under study are suggested to have a strong phylogenetic signal in this clade, the ancestry playing a big role in reproduction. The EF also influenced the reproduction of South American xenodontines, although to a lesser extent. Our finding provides new evidence of how the evolutionary history is embodied in the traits of living species.     

Stereochemistry of the hydrolysis of α,α-trehalose by trehalase,determined by using a labelled substrate

(1,1′-¹³C)α,α-Trehalose was obtained in 37% yield from the Pavia condensation of 2,3,4,6-tetra-O-benzyl-d-(1-¹³C)glucopyranose, in dichloromethane in the presence of trifluoromethanesulfonic anhydride, followed by the usual deprotection techniques. The hydrolysis of this substrate by cockchafer trehalase was monitored at 37° by using ¹³C-n.m.r. spectroscopy with short recording times. Equimolecular amounts of α- and β-d-glucopyranose are released simultaneously by the action of the enzyme. This result is consistent with a bimolecular substitution mechanism, taking into account previous results involving C-2 asymmetric participation in the catalytic step of hydrolysis of α,α-trehalose. For comparative evaluation of its accuracy, the usual polarimetric technique was also used for the determination of the anomeric configuration of the d-glucose released by the action of the enzyme on α,α-trehalose.     

Microenvironment and tumors—a nurturing relationship

When exposed to adverse environmental conditions, cells degrade their own content to recycle cellular building blocks through a process called autophagy. A large body of literature has connected autophagy to cancer, but most studies up until now focused on its function in transformed cells. In her thesis, Nadja Katheder dissected the role of autophagy in a well-characterized neoplastic in vivo tumor model in Drosophila and demonstrates a novel non-cell-autonomous requirement of this process for tumor growth. Neighboring epithelial cells and distal tissues increase autophagy in the presence of a malignant tumor. Pharmacological autophagy inhibition reduces tumor growth and genetic ablation of autophagy in the microenvironment reveals a tumor-supportive role of this process in this specific cell population. Tumor cells are metabolically stressed and induce autophagy in their neighbors through a TNFα-JNK-IL-6 signaling cascade. Moreover, they are dependent on amino acid import to sustain their proliferation, which indicates a coupling of metabolism between these two cell populations. Finally, allografted growth-impaired tumors from autophagy-deficient donor animals resume growth in an autophagy-competent host. Together, the results described in this thesis highlight the tumor-promoting role of autophagy the microenvironment and show that cancer cells engage their epithelial neighbors as essential contributors aiding their own growth.     

Sparse distribution of γ/δ T lymphocytes around human epithelial tumors predominantly infiltrated by primed/memory T cells

Summary Evidence from the mouse system has suggested that T lymphocytes accumulating in non-lymphoid tissue, in particular epithelia, may preferentially express the T cell receptor (TCR) . In this study, we characterize the T cell receptor or phenotype of lymphocytes infiltrating human tumors of epithelial origin using monoclonal antibodies (mAb) for immunohistology and flow cytometry on cells extracted by enzyme digestion. This report shows that the majority of CD3⁺ tumor-infiltrating lymphocytes are TCR ⁺ but a small percentage of TCR can be clearly defined scattered throughout the tumor tissue with apparently no microanatomical selection. So far there has been little evidence for an accumulation of activated T cells in human tumor tissues as defined by mAb against molecules appearing transiently during the acute phase of activation. Now mAb are available that can identify primed or memory T cells such as mAb UCHL-1 recognizing the CD45RO antigen. Here we show that CD3⁺ tumor-infiltrating lymphocytes have a statistically significant accumulation of primed T cells, as compared to the autologous peripheral blood lymphocytes, suggesting their immune stimulation by tumor cells.     

Hypoxia and TGF-β1 lead to endostatin resistance by cooperatively increasing cancer stem cells in A549 transplantation tumors

Background

Lung cancer is the leading cause of cancer-related deaths worldwide, and treatments for lung cancer have a high failure rate. Anti-angiogenic therapy is also often ineffective because of refractory disease. Endostatin (ES) is one of the most widely-used anti-angiogenic drugs for lung cancer in China, and resistance to it is a barrier that needs to be resolved. It has been shown that myeloid-derived suppressor cells (MDSCs) are involved in resistance to ES. Whether other cells and/or cell factors in the tumor microenvironment that have been shown to be related to resistance to other anti-cancer drugs are also involved in ES resistance is unknown.

Results

In this study, we showed that after continuously treatment with ES for 12 days, volumes of A549 transplantation tumors of mice reached the sizes of tumors which were borne by mice that were treated with normal saline and this meant that resistance to ES appeared. Cancer stem cells (CSCs), which have been widely accepted as one of reasons responsible for resistance to many anti-tumor drugs were also being discovered increased proportionally in A549 transplantation tumors after ES treatment for 12 days. During further exploration of reasons for this increase, we discovered that after ES treatment, microvessel density and vascular endothelial growth factor level was decreased in tumors, whereas transforming growth factor (TGF)-β1 level was elevated, and MDSCs, one of the sources of TGF-β1, were also increased. We speculate that hypoxia and TGF-β1 are responsible for the increased CSC number in A549 transplantation tumors. By using cobalt chloride to mimic hypoxia and human recombinant TGF-β1 in vitro, we found that hypoxia and TGF-β1can indeed enhance the stemness of A549 cells. In addition, the inductive effect of hypoxia is stronger than TGF-β1, and the combination of both is stronger than either alone, which is first report of such a finding, to our knowledge.

Conclusions

Increased TGF-β1 and strengthened hypoxia in A549 transplantation tumors, as a result of ES therapy, cooperatively increase proportion of CSCs that are involved in ES resistance which was revealed by failure of tumor volume repression after continuously treatment with ES for 12 days.