Tumor necrosis factor-mediated interactions between inflammatory response and tumor vascular bed

Toll-like receptor 4 signaling activation domains promote CAR T cell function against solid tumors

Chimeric antigen receptor (CAR) T cell therapy has emerged as a powerful therapeutic approach against a range of hematologic malignancies. While the incorporation of CD28 or 4-1BB costimulatory signaling domains into CARs revolutionized immune responses, there is an exciting prospect of further enhancing CAR functionality. Here, we investigated the design of CD19 CARs enriched with distinct Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), or Toll/IL-1 domain-containing adaptor-inducing interferon (IFN)-β (TRIF) costimulatory domains. Screening of various designs identified several candidates with no tonic activity but with increased CD19 target cell-dependent interleukin (IL)-2 production. Human T cells transduced with the selected CAR construct exhibited augmented hIL-2 and hIFN-γ induction and cytotoxicity when cocultured with CD19-positive lymphoma and solid-tumor cell lines. RNA sequencing (RNA-seq) analysis demonstrated the upregulation of some genes involved in the innate immune response and T cell activation and proliferation. In experiments on a xenogeneic solid-tumor mice model, MyD88 and TLR4 CAR T cells exhibited prolonged remission. This study demonstrates that the integration of a truncated TLR4 signaling costimulatory domain could provide immunotherapeutic potential against both hematologic malignancies and solid tumors.

Role of Immune Checkpoint Inhibitor Therapy in Advanced EGFR-Mutant Non-Small Cell Lung Cancer

Over the last decade, the treatment of advanced non-small cell lung cancer (NSCLC) has undergone rapid changes with innovations in oncogene-directed therapy and immune checkpoint inhibitors. In patients with epidermal growth factor receptor (EGFR) gene mutant (EGFRm) NSCLC, newer-generation tyrosine kinase inhibitors (TKIs) are providing unparalleled survival benefit and tolerability. Unfortunately, most patients will experience disease progression and thus an urgent need exists for improved subsequent lines of therapies. The concurrent revolution in immune checkpoint inhibitor (ICI) therapy is providing novel treatment options with improved clinical outcomes in wild-type EGFR (EGFRwt) NSCLC; however, the application of ICI therapy to advanced EGFRm NSCLC patients is controversial. Early studies demonstrated the inferiority of ICI monotherapy to EGFR TKI therapy in the first line setting and inferiority to chemotherapy in the second line setting. Additionally, combination ICI and EGFR TKI therapies have demonstrated increased toxicities, and EGFR TKI therapy given after first-line ICI therapy has been correlated with severe adverse events. Nonetheless, combination therapies including dual-ICI blockade and ICI, chemotherapy, and angiogenesis inhibitor combinations are areas of active study with some intriguing signals in preliminary studies. Here, we review previous and ongoing clinical studies of ICI therapy in advanced EGFRm NSCLC. We discuss advances in understanding the differences in the tumor biology and tumor microenvironment (TME) of EGFRm NSCLC tumors that may lead to novel approaches to enhance ICI efficacy. It is our goal to equip the reader with a knowledge of current therapies, past and current clinical trials, and active avenues of research that provide the promise of novel approaches and improved outcomes for patients with advanced EGFRm NSCLC.

"Designer cytokines" targeting the tumor vasculature-think global and act local

Tumor necrosis factor (TNF) was discovered in 1975 as a lipopolysaccharide‐induced serum factor that causes necrosis of tumors (Carswell et al, 1975). It was later found that TNF and cachectin, a factor causing wasting disease, were one and the same molecule (Beutler et al, 1985). Studies on the inflammatory activity of TNF have been translated into clinical success, namely blocking antibodies used to suppress autoimmune diseases. Research on TNF anti‐tumor activity, in contrast, has not yet resulted in a therapeutic breakthrough. This may change, based on a study by Huyghe et al (2020) describing novel “designer cytokines” (TNF and interferon‐γ) that increase local activity by targeting the CD13‐positive tumor vasculature, while simultaneously lowering the binding affinity to the respective cytokine receptor, thereby reducing off‐target effects on normal cells.

A novel vascular-targeting peptide for gastric cancer delivers low-dose TNFα to normalize the blood vessels and improve the anti-cancer efficiency of 5-fluorouracil

Various vascular-targeted agents fused with tumor necrosis factor α (TNFα) have been shown to improve drug absorption into tumor tissues and enhance tumor vascular function. TCP-1 is a peptide selected through in vivo phage library biopanning against a mouse orthotopic colorectal cancer model and is a promising agent for drug delivery. This study further investigated the targeting ability of TCP-1 phage and peptide to blood vessels in an orthotopic gastric cancer model in mice and assessed the synergistic anti-cancer effect of 5-fluorouracil (5-FU) with subnanogram TNFα targeted delivered by TCP-1 peptide. In vivo phage targeting assay and in vivo colocalization analysis were carried out to test the targeting ability of TCP-1 phage/peptide. A targeted therapy for improvement of the therapeutic efficacy of 5-FU and vascular function was performed through administration of TCP-1/TNFα fusion protein in this model. TCP-1 phage exhibited strong homing ability to the orthotopic gastric cancer after phage injection. Immunohistochemical staining suggested that and TCP-1 phage/TCP-1 peptide could colocalize with tumor vascular endothelial cells. TCP-1/TNFα combined with 5-FU was found to synergistically inhibit tumor growth, induce apoptosis and reduce cell proliferation without evident toxicity. Simultaneously, subnanogram TCP-1/TNFα treatment normalized tumor blood vessels. Targeted delivery of low-dose TNFα by TCP-1 peptide can potentially modulate the vascular function of gastric cancer and increase the drug delivery of chemotherapeutic drugs.

Fine-Tuning Tumor Endothelial Cells to Selectively Kill Cancer

Tumor endothelial cells regulate several aspects of tumor biology, from delivering oxygen and nutrients to shaping the immune response against a tumor and providing a barrier against tumor cell dissemination. Accordingly, targeting tumor endothelial cells represents an important modality in cancer therapy. Whereas initial anti-angiogenic treatments focused mainly on blocking the formation of new blood vessels in cancer, emerging strategies are specifically influencing certain aspects of tumor endothelial cells. For instance, efforts are generated to normalize tumor blood vessels in order to improve tumor perfusion and ameliorate the outcome of chemo-, radio-, and immunotherapy. In addition, treatment options that enhance the properties of tumor blood vessels that support a host’s anti-tumor immune response are being explored. Hence, upcoming anti-angiogenic strategies will shape some specific aspects of the tumor blood vessels that are no longer limited to abrogating angiogenesis. In this review, we enumerate approaches that target tumor endothelial cells to provide anti-cancer benefits and discuss their therapeutic potential.

The therapeutic T-cell response induced by tumor delivery of TNF and melphalan is dependent on early triggering of natural killer and dendritic cells

The fusion protein L19mTNF (mouse TNF and human antibody fragment L19 directed to fibronectin extra domain B) selectively targets the tumor vasculature, and in combination with melphalan induces a long-lasting T-cell therapeutic response and immune memory in murine models. Increasing evidence suggests that natural killer (NK) cells act to promote effective T-cell-based antitumor responses. We have analyzed the role of NK cells and dendritic cells (DCs) on two different murine tumor models: WEHI-164 fibrosarcoma and C51 colon carcinoma, in which the combined treatment induces high and low rejection rates, respectively. In vivo NK-cell depletion strongly reduced the rejection of WEHI-164 fibrosarcoma and correlated with a decrease in mature DCs, CD4⁺ , and CD8⁺ T cells in the tumor-draining LNs and mature DCs and CD4⁺ T cells in the tumor 40 h after initiation of the therapy. NK-cell depletion also resulted in the impairment of the stimulatory capability of DCs derived from tumor-draining LNs of WEHI-164-treated mice. Moreover, a significant reduction of M2-type infiltrating macrophages was detected in both tumors undergoing therapy. These results suggest that the efficacy of L19mTNF/melphalan therapy is strongly related to the early activation of NK cells and DCs, which are necessary for an effective T-cell response.

Augmentation of cellular and humoral immune responses to HPV16 and HPV18 E6 and E7 antigens by VGX-3100

We have previously demonstrated the immunogenicity of VGX-3100, a multicomponent DNA immunotherapy for the treatment of Human Papillomavirus (HPV)16/18-positive CIN2/3 in a phase 1 clinical trial. Here, we report on the ability to boost immune responses with an additional dose of VGX-3100. Patients completing our initial phase 1 trial were offered enrollment into a follow on trial consisting of a single boost dose of VGX-3100. Data show both cellular and humoral immune responses could be augmented above pre-boost levels, including the induction of interferon (IFN)γ production, tumor necrosis factor (TNF)α production, CD8+ T cell activation and the synthesis of lytic proteins. Moreover, observation of antigen-specific regulation of immune-related gene transcripts suggests the induction of a proinflammatory response following the boost. Analysis of T cell receptor (TCR) sequencing suggests the localization of putative HPV-specific T cell clones to the cervical mucosa, which underscores the putative mechanism of action of lesion regression and HPV16/18 elimination noted in our double-blind placebo-controlled phase 2B trial. Taken together, these data indicate that VGX-3100 drives the induction of robust cellular and humoral immune responses that can be augmented by a fourth "booster" dose. These data could be important in the scope of increasing the clinical efficacy rate of VGX-3100.

New possible biomarkers for diagnosis of infections and diagnostic distinction between bacterial and viral infections in children

Detailed information about patients with infections is required to ensure appropriate choice of treatment. Although white blood cell (WBC) counts, and C-reactive protein (CRP) levels are useful diagnostic indicators of infections, more rapid and easily assayed indicator(s) could improve diagnosis. Moreover, it is of pivotal importance to distinguish bacteria or viruses as causative pathogens. Overall, TLR2 and TLR4 expression levels in neutrophils derived from individuals (n = 118) with bacterial (n = 37) and viral (n = 34) infections were higher than those in control samples (n = 47). Significant higher levels of TNF-α in patients with both types of the infection were observed, and those of IL-4, IL-8, IL-10, and IL-12 also were observed in the present study. Levels of IL-2, IL-8, and IL-10 on day 1 post-viral infection were significantly higher than those on day 1 post-bacterial infection. Therefore, there is a possibility that IL-4, IL-8, IL-10, IL-12 and TNF-α might be biomarkers for infections, in addition to WBC counts and CRP levels, and that IL-2, IL-8 or IL-10 are potentially able to distinguish between bacterial and viral infections.

Vascular-targeted TNFα improves tumor blood vessel function and enhances antitumor immunity and chemotherapy in colorectal cancer

Delivery and penetration of chemotherapeutic drugs into neoplasm through the tumor vasculature are essential mechanisms to enhance the efficiency of chemotherapy. "Vascular targeting" strategy focuses on promoting the infiltration of chemotherapeutic drugs into neoplastic tissues. In this study, we achieved a targeted therapy by coupling tumor necrosis factor α (TNFα) with TCP-1, a novel vascular-targeting peptide, in an orthotopic colorectal cancer model in mice. High dose of TCP-1-conjugated TNFα (TCP-1/TNFα: 5μg/mouse) displayed potent antitumor activity by inducing apoptosis and reducing microvessel number in tumors than unconjugated TNFα, with no evidence of increased toxicity. In the combined therapy, the antitumor action of 5-fluorouracil (5-FU) was potentiated when the mice were pretreated with a low dose of TNFα (1ng/mouse) and to a greater extent by the same concentration of TCP-1/TNFα. In this regard, TCP-1/TNFα combined with 5-FU synergistically inhibited the tumor growth, induced apoptosis and reduced cell proliferation. More importantly, TCP-1/TNFα normalized the tumor vasculature and facilitated the infiltration of immune cells to neoplasm as well as attenuated the immunosuppressing effects of TNFα in bone marrow and spleen. At the same time, TCP-1/TNFα significantly improved 5-FU absorption into the tumor mass. Taken together, these findings underscore the therapeutic potential of TCP-1 as a drug carrier in cancer therapy. TCP-1 is a novel vascular-targeting peptide and appears to be a promising agent for drug delivery. TCP-1 fused with TNFα holds great promise for colorectal cancer therapy.

Targeting the tumor vasculature to enhance T cell activity

T cells play a critical role in tumor immune surveillance as evidenced by extensive mouse-tumor model studies as well as encouraging patient responses to adoptive T cell therapies and dendritic cell vaccines. It is well established that the interplay of tumor cells with their local cellular environment can trigger events that are immunoinhibitory to T cells. More recently it is emerging that the tumor vasculature itself constitutes an important barrier to T cells. Endothelial cells lining the vessels can suppress T cell activity, target them for destruction, and block them from gaining entry into the tumor in the first place through the deregulation of adhesion molecules. Here we review approaches to break this tumor endothelial barrier and enhance T cell activity.

Targeting the tumor microenvironment to enhance antitumor immune responses

The identification of tumor-specific antigens and the immune responses directed against them has instigated the development of therapies to enhance antitumor immune responses. Most of these cancer immunotherapies are administered systemically rather than directly to tumors. Nonetheless, numerous studies have demonstrated that intratumoral therapy is an attractive approach, both for immunization and immunomodulation purposes. Injection, recruitment and/or activation of antigen-presenting cells in the tumor nest have been extensively studied as strategies to cross-prime immune responses. Moreover, delivery of stimulatory cytokines, blockade of inhibitory cytokines and immune checkpoint blockade have been explored to restore immunological fitness at the tumor site. These tumor-targeted therapies have the potential to induce systemic immunity without the toxicity that is often associated with systemic treatments. We review the most promising intratumoral immunotherapies, how these affect systemic antitumor immunity such that disseminated tumor cells are eliminated, and which approaches have been proven successful in animal models and patients.

TNF-α-dependent hematopoiesis following Bcl11b deletion in T cells restricts metastatic melanoma

Using several tumor models, we demonstrate that mice deficient in Bcl11b in T cells, although having reduced numbers of T cells in the peripheral lymphoid organs, developed significantly less tumors compared with wild-type mice. Bcl11b(-/-) CD4(+) T cells, with elevated TNF-α levels, but not the Bcl11b(-/-) CD8(+) T cells, were required for the reduced tumor burden, as were NK1.1(+) cells, found in increased numbers in Bcl11b(F/F)/CD4-Cre mice. Among NK1.1(+) cells, the NK cell population was predominant in number and was the only population displaying elevated granzyme B levels and increased degranulation, although not increased proliferation. Although the number of myeloid-derived suppressor cells was increased in the lungs with metastatic tumors of Bcl11b(F/F)/CD4-Cre mice, their arginase-1 levels were severely reduced. The increase in NK cell and myeloid-derived suppressor cell numbers was associated with increased bone marrow and splenic hematopoiesis. Finally, the reduced tumor burden, increased numbers of NK cells in the lung, and increased hematopoiesis in Bcl11b(F/F)/CD4-Cre mice were all dependent on TNF-α. Moreover, TNF-α treatment of wild-type mice also reduced the tumor burden and increased hematopoiesis and the numbers and activity of NK cells in the lung. In vitro treatment with TNF-α of lineage-negative hematopoietic progenitors increased NK and myeloid differentiation, further supporting a role of TNF-α in promoting hematopoiesis. These studies reveal a novel role for TNF-α in the antitumor immune response, specifically in stimulating hematopoiesis and increasing the numbers and activity of NK cells.

Ways to enhance lymphocyte trafficking into tumors and fitness of tumor infiltrating lymphocytes

The tumor is a hostile microenvironment for T lymphocytes. Indeed, irregular blood flow, and endothelial cell (EC) anergy that characterize most solid tumors hamper leukocyte adhesion, extravasation, and infiltration. In addition, hypoxia and reprograming of energy metabolism within cancer cells transform the tumor mass in a harsh environment that limits survival and effector functions of T cells, regardless of being induced in vivo by vaccination or adoptively transferred. In this review, we will summarize on recent advances in our understanding of the characteristics of tumor-associated neo-angiogenic vessels as well as of the tumor metabolism that may impact on T cell trafficking and fitness of tumor infiltrating lymphocytes. In particular, we will focus on how advances in knowledge of the characteristics of tumor ECs have enabled identifying strategies to normalize the tumor-vasculature and/or overcome EC anergy, thus increasing leukocyte-vessel wall interactions and lymphocyte infiltration in tumors. We will also focus on drugs acting on cells and their released molecules to transiently render the tumor microenvironment more suitable for tumor infiltrating T lymphocytes, thus increasing the therapeutic effectiveness of both active and adoptive immunotherapies.

Comprehensive assessment of the association between tumor necrosis factor alpha G238A polymorphism and liver cancer risk

Tumor necrosis factor alpha (TNF-α) has been suggested to play an important role in the development and liver cancer. TNF-α 238 G/A polymorphism was hypothesized to increase the risk of liver cancer, but findings from previous studies were controversial. To explore a more precise estimation of the relationship between TNF-α 238 G/A polymorphism and liver cancer, we performed a meta-analysis. PubMed, Embase, and China Biology Medicine databases were searched for all publications on this association through March 12, 2013. Odds ratios (ORs) with its 95% confidence intervals (CIs) were used to assess the strength of this association. Eleven studies with 1,406 liver cancer cases and 2,386 noncancer controls were included into this meta-analysis. Overall, there was a significant association between TNF-α 238 G/A polymorphism and increased risk of liver cancer under all three genetic models (A vs. G, OR 1.51, 95% CI 1.20-1.89, P < 0.001, I(2) = 37.7%; AG vs. GG, OR 1.49, 95% CI 1.01-2.21, P = 0.045, I(2) = 53.2%; AA/AG vs. GG, OR 1.76, 95% CI 1.35-2.30, P < 0.001, I(2) = 36.5%). The sensitivity analysis further strengthened the validity of the positive association. Subgroup analysis of nine studies from Asian countries showed that there was a significant association between TNF-α 238 G/A polymorphism and increased risk of liver cancer in Asians (A vs. G, OR 1.35, 95% CI 1.03-1.76, P = 0.027, I(2) = 40.2%; AA/AG vs. GG, OR 1.56, 95% CI 1.14-2.15, P = 0.006, I(2) = 41.9%). In conclusion, TNF-α 238 G/A polymorphism is significantly associated with increased risk of liver cancer, especially in Asians.

Influence of levamisole and other angiogenesis inhibitors on angiogenesis and endothelial cell morphology in vitro

Angiogenesis, the formation of new blood vessels from existing vessels is required for many physiological processes and for growth of solid tumors. Initiated by hypoxia, angiogenesis involves binding of angiogenic factors to endothelial cell (EC) receptors and activation of cellular signaling, differentiation, migration, proliferation, interconnection and canalization of ECs, remodeling of the extracellular matrix and stabilization of newly formed vessels. Experimentally, these processes can be studied by several in vitro and in vivo assays focusing on different steps in the process. In vitro, ECs form networks of capillary-like tubes when propagated for three days in coculture with fibroblasts. The tube formation is dependent on vascular endothelial growth factor (VEGF) and omission of VEGF from the culture medium results in the formation of clusters of undifferentiated ECs. Addition of angiogenesis inhibitors to the coculture system disrupts endothelial network formation and influences EC morphology in two distinct ways. Treatment with antibodies to VEGF, soluble VEGF receptor, the VEGF receptor tyrosine kinase inhibitor SU5614, protein tyrosine phosphatase inhibitor (PTPI) IV or levamisole results in the formation of EC clusters of variable size. This cluster morphology is a result of inhibited EC differentiation and levamisole can be inferred to influence and block VEGF signaling. Treatment with platelet factor 4, thrombospondin, rapamycin, suramin, TNP-470, salubrinal, PTPI I, PTPI II, clodronate, NSC87877 or non-steriodal anti-inflammatory drugs (NSAIDs) results in the formation of short cords of ECs, which suggests that these inhibitors have an influence on later steps in the angiogenic process, such as EC proliferation and migration. A humanized antibody to VEGF is one of a few angiogenesis inhibitors used clinically for treatment of cancer. Levamisole is approved for clinical treatment of cancer and is interesting with respect to anti-angiogenic activity in vivo since it inhibits ECs in vitro with a morphology resembling that obtained with antibodies to VEGF.

Drug targeting to tumors: principles, pitfalls and (pre-) clinical progress

Many different systems and strategies have been evaluated for drug targeting to tumors over the years. Routinely used systems include liposomes, polymers, micelles, nanoparticles and antibodies, and examples of strategies are passive drug targeting, active drug targeting to cancer cells, active drug targeting to endothelial cells and triggered drug delivery. Significant progress has been made in this area of research both at the preclinical and at the clinical level, and a number of (primarily passively tumor-targeted) nanomedicine formulations have been approved for clinical use. Significant progress has also been made with regard to better understanding the (patho-) physiological principles of drug targeting to tumors. This has led to the identification of several important pitfalls in tumor-targeted drug delivery, including I) overinterpretation of the EPR effect; II) poor tumor and tissue penetration of nanomedicines; III) misunderstanding of the potential usefulness of active drug targeting; IV) irrational formulation design, based on materials which are too complex and not broadly applicable; V) insufficient incorporation of nanomedicine formulations in clinically relevant combination regimens; VI) negligence of the notion that the highest medical need relates to metastasis, and not to solid tumor treatment; VII) insufficient integration of non-invasive imaging techniques and theranostics, which could be used to personalize nanomedicine-based therapeutic interventions; and VIII) lack of (efficacy analyses in) proper animal models, which are physiologically more relevant and more predictive for the clinical situation. These insights strongly suggest that besides making ever more nanomedicine formulations, future efforts should also address some of the conceptual drawbacks of drug targeting to tumors, and that strategies should be developed to overcome these shortcomings.

Proapoptotic activation of death receptor 5 on tumor endothelial cells disrupts the vasculature and reduces tumor growth

The proapoptotic death receptor DR5 has been studied extensively in cancer cells, but its action in the tumor microenvironment is not well defined. Here, we uncover a role for DR5 signaling in tumor endothelial cells (ECs). We detected DR5 expression in ECs within tumors but not normal tissues. Treatment of tumor-bearing mice with an oligomeric form of the DR5 ligand Apo2L/TRAIL induced apoptosis in tumor ECs, collapsing blood vessels and reducing tumor growth: Vascular disruption and antitumor activity required DR5 expression on tumor ECs but not malignant cells. These results establish a therapeutic paradigm for proapoptotic receptor agonists as selective tumor vascular disruption agents, providing an alternative, perhaps complementary, strategy to their use as activators of apoptosis in malignant cells.

Hepatic arterial infusion with tumor necrosis factor-α induces early hepatic hyperperfusion

BACKGROUND

Hepatic arterial infusion (HAI) has been developed for high-dose regional chemotherapy of unresectable liver metastases or primary liver malignancies. While it is well known that high concentrations of tumor necrosis factor (TNF)-α damage tumor blood perfusion, there is no information on whether autochthonous liver perfusion is affected by HAI with TNF-α. Therefore, we investigated the effects of HAI with TNF-α on hepatic macro- and microvascular perfusion.

METHODS

Swabian Hall pigs were randomized into three groups. HAI was performed with either 20 or 40 µg/kg body weight TNF-α (n = 6 each group). Saline-treated animals served as controls (n = 6). Analyses during a 2-hour post-HAI observation period included systemic hemodynamics, portal venous and hepatic arterial blood flow, portal venous pressure, and the blood flow in the hepatic microcirculation.

RESULTS

HAI with TNF-α caused a slight decrease of mean arterial blood pressure (p < 0.001), which was compensated by a moderate increase of heart rate (p < 0.001). No further systemic side effects of TNF-α were observed. HAI with TNF-α further caused a slight but not significant decrease of portal venous blood flow (p = 0.737) in both experimental groups, paralleled by an increase of hepatic arterial blood flow (p = 0.023, 20 µg/kg; p = 0.034, 40 µg/kg) resulting in an overall hepatic hyperperfusion. The hepatic hyperperfusion after HAI with 20 µg/kg TNF-α was more pronounced and associated with a 40% decrease of the blood flow in the hepatic microcirculation (p = 0.009). HAI with 40 µg/kg TNF-α was only associated with a temporary and moderate total hepatic hyperperfusion and did not affect the blood flow in the hepatic microcirculation.

CONCLUSION

HAI with TNF-α causes a decrease of portal venous flow; however, this is overcompensated by an increased hepatic arterial blood flow, resulting in a total hepatic hyperperfusion. Moderate total hepatic hyperperfusion does not affect the blood flow in the hepatic microcirculation, while a persistent and more pronounced hyperperfusion may cause hepatic microcirculatory disturbances.

Targeting TNF-α to neoangiogenic vessels enhances lymphocyte infiltration in tumors and increases the therapeutic potential of immunotherapy

Abnormal tumor vasculature impairs T lymphocyte adhesion to endothelial cells and lymphocyte extravasation into neoplastic tissues, limiting the therapeutic potential of both active and adoptive immunotherapies. We have found that treatment of tumor-bearing mice with NGR-TNF, a Cys-Asn-Gly-Arg-Cys peptide-TNF fusion product capable of altering the endothelial barrier function and improving drug penetration in tumors, associated with the intratumor upregulation of leukocyte-endothelial cell adhesion molecules, the release of proinflammatory cytokines and chemokines, and the infiltration of tumor-specific effector CD8(+) T cells. As a result, NGR-TNF enhanced the therapeutic activity of adoptive and active immunotherapy, delaying tumor growth and prolonging survival. Furthermore, we have found that therapeutic effects of these combinations can be further increased by the addition of chemotherapy. Thus, these findings might be relevant for the design of novel immunotherapeutic approaches for cancer patients.

Creating a tumor-resistant microenvironment: cell-mediated delivery of TNFα completely prevents breast cancer tumor formation in vivo

Here, we provide the necessary proof of concept, that it is possible to metabolically create a non-permissive or "hostile" stromal microenvironment, which actively prevents tumor engraftment in vivo. We developed a novel genetically engineered fibroblast cell line that completely prevents tumor formation in mice, with a 100% protection rate. No host side effects were apparent. This could represent a viable cellular strategy for preventing and treating a variety of human cancers. More specifically, we examined the autocrine and paracrine effects of the cellular delivery of TNFα on breast cancer tumor growth and cancer metabolism. For this purpose, we recombinantly overexpressed TNFα in human breast cancer cells (MDA-MB-231) or human immortalized fibroblasts (hTERT-BJ1). Our results directly show that TNFα functions as a potent tumor suppressor. Remarkably, TNFα-expressing breast cancer cells were viable, without any significant increases in their basal apoptotic rate. However, after 4 weeks post-implantation, TNFα-expressing breast cancer cells failed to form any tumors in xenografted mice (0 tumors/10 injections), ultimately conferring 100% protection against tumorigenesis. Similarly, TNFα-overexpressing fibroblasts were also viable, without any increases in apoptosis. Significantly, complete tumor suppression was obtained by co-injecting TNFα expressing stromal fibroblasts with human breast cancer cells, indicating that paracrine cell-mediated delivery of TNFα can also prevent tumor engraftment and growth (0 tumors/10 injections). Mechanistically, TNFα induced autophagy and mitochondrial dysfunction in both epithelial cancer cells and stromal fibroblasts, preventing energy transfer from the tumor microenvironment, likely "starving" the cancer cells to death. In addition, via qRT-PCR analysis of MDA-MB-231 cells, we observed that TNFα mediated the upregulation of gene transcripts associated with inflammation and senescence [IL-1-β, IL-6, IL-8, MCP-1, COX-2, p21(WAF1/CIP1)] and downregulated known tumor-promoting genes (collagen VI and MMP2). Recombinant overexpression of TNFα receptor(s) in MDA-MB-231 cells also significantly reduced tumor growth, but was not as effective as the TNFα ligand itself in preventing tumor growth. Thus, we propose that stromal cell-mediated delivery of TNFα to human tumors [using transfected fibroblasts or mesenchymal stem cells (hMSCs)] may be a novel and effective strategy for the prevention and treatment of human cancers.

Tumor-promoting circuits that regulate a cancer-related chemokine cluster: dominance of inflammatory mediators over oncogenic alterations

Here, we investigated the relative contribution of genetic/signaling components versus microenvironmental factors to the malignancy phenotype. In this system, we took advantage of non-transformed fibroblasts that carried defined oncogenic modifications in Ras and/or p53. These cells were exposed to microenvironmental pressures, and the expression of a cancer-related chemokine cluster was used as readout for the malignancy potential (CCL2, CCL5, CXCL8, CXCL10). In cells kept in-culture, synergism between Ras hyper-activation and p53 dysfunction was required to up-regulate the expression of the chemokine cluster. The in vivo passage of RasHigh/p53Low-modified cells has led to tumor formation, accompanied by potentiation of chemokine release, implicating a powerful role for the tumor microenvironment in up-regulating the chemokine cluster. Indeed, we found that inflammatory mediators which are prevalent in tumor sites, such as TNFa and IL-1β, had a predominant impact on the release of the chemokines, which was substantially higher than that obtained by the oncogenic modifications alone, possibly acting through the transcription factors AP-1 and NF-kB. Together, our results propose that in the unbiased model system that we were using, inflammatory mediators of the tumor milieu have dominating roles over oncogenic modifications in dictating the expression of a pro-malignancy chemokine readout.

The Tumor-Promoting Flow of Cells Into, Within and Out of the Tumor Site: Regulation by the Inflammatory Axis of TNFα and Chemokines

Tumors are dynamic organs, in which active processes of cell motility affect disease course by regulating the composition of cells at the tumor site. While sub-populations of tumor-promoting leukocytes are recruited inward and endothelial cell migration stands in the basis of vascular branching throughout the tumor, cancer cells make their way out of the primary site towards specific metastatic sites. This review describes the independent and cross-regulatory roles of inflammatory chemokines and of the inflammatory cytokine tumor necrosis factor α (TNFα) in determining cell motility processes that eventually have profound effects on tumor growth and metastasis. First, the effects of inflammatory chemokines such as CCL2 (MCP-1), CCL5 (RANTES) and CXCL8 (IL-8) are described, regulating the inward flow of leukocyte sub-populations with pro-tumoral activities, such as tumor-associated macrophages (TAM), myeloid-derived suppressor cells (MDSC), tumor-associated neutrophils (TAN), Th17 cells and Tregs. Then, the ability of inflammatory chemokines to induce endothelial cell migration, sprouting and tube formation is discussed, with its implications on tumor angiogenesis. This part is followed by an in depth description of the manners by which TNFα potentiates the above activities of the inflammatory chemokines, alongside with its ability to directly induce migratory processes in the tumor cells thus promoting metastasis. Note worthy is the ability of TNFα to induce in the tumor cells the important process of epithelial-to-mesenchymal transition (EMT). Emphasis is given to the ability of TNFα to establish an inflammatory network with the chemokines, and in parallel to form a cell re-modeling network together with transforming growth factor β (TGFβ). The review concludes by discussing the implications of such networks on disease course, and on the future design of therapeutic measures in cancer.

Nanoparticle preconditioning for enhanced thermal therapies in cancer

Nanoparticles show tremendous promise in the safe and effective delivery of molecular adjuvants to enhance local cancer therapy. One important form of local cancer treatment that suffers from local recurrence and distant metastases is thermal therapy. In this article, we review a new concept involving the use of nanoparticle-delivered adjuvants to 'precondition' or alter the vascular and immunological biology of the tumor to enhance its susceptibility to thermal therapy. To this end, a number of opportunities to combine nanoparticles with vascular and immunologically active agents are reviewed. One specific example of preconditioning involves a gold nanoparticle tagged with a vascular targeting agent (i.e., TNF-α). This nanoparticle embodiment demonstrates preconditioning through a dramatic reduction in tumor blood flow and induction of vascular damage, which recruits a strong and sustained inflammatory infiltrate in the tumor. The ability of this nanoparticle preconditioning to enhance subsequent heat or cold thermal therapy in a variety of tumor models is reviewed. Finally, the potential for future clinical imaging to judge the extent of preconditioning and thus the optimal timing and extent of combinatorial thermal therapy is discussed.

Similar NF-κB gene signatures in TNF-α treated human endothelial cells and breast tumor biopsies

BACKGROUND

Endothelial dysfunction has been implicated in the pathogenesis of diverse pathologies ranging from vascular and immune diseases to cancer. TNF-α is one of the mediators of endothelial dysfunction through the activation of transcription factors, including NF-κB. While HUVEC (macrovascular cells) have been largely used in the past, here, we documented an NF-κB gene signature in TNFα-stimulated microvascular endothelial cells HMEC often used in tumor angiogenesis studies.

METHODOLOGY/PRINCIPAL FINDINGS

We measured mRNA expression of 55 NF-κB related genes using quantitative RT-PCR in HUVEC and HMEC. Our study identified twenty genes markedly up-regulated in response to TNFα, including adhesion molecules, cytokines, chemokines, and apoptosis regulators, some of them being identified as TNF-α-inducible genes for the first time in endothelial cells (two apoptosis regulators, TNFAIP3 and TNFRSF10B/Trail R2 (DR5), the chemokines GM-CSF/CSF2 and MCF/CSF1, and CD40 and TNF-α itself, as well as NF-κB components (RELB, NFKB1 or 50/p105 and NFKB2 or p52/p100). For eight genes, the fold induction was much higher in HMEC, as compared to HUVEC. Most importantly, our study described for the first time a connection between NF-κB activation and the induction of most, if not all, of these genes in HMEC as evaluated by pharmacological inhibition and RelA expression knock-down by RNA interference. Moreover, since TNF-α is highly expressed in tumors, we further applied the NF-κB gene signature documented in TNFα-stimulated endothelial cells to human breast tumors. We found a significant positive correlation between TNF and the majority (85 %) of the identified endothelial TNF-induced genes in a well-defined series of 96 (48 ERα positive and 48 ERα negative) breast tumors.

CONCLUSION/SIGNIFICANCE

Taken together these data suggest the potential use of this NF-κB gene signature in analyzing the role of TNF-α in the endothelial dysfunction, as well as in breast tumors independently of the presence of ERα.

Therapy-induced antitumor vaccination in neuroblastomas by the combined targeting of IL-2 and TNFalpha

L19-IL2 and L19TNFalpha are fusion proteins composed of L19(scFv), specific for the angiogenesis-associated ED-B containing fibronectin isoform and IL-2 or TNFalpha. Because of the tumor targeting properties of L19, IL-2 and TNFalpha concentrate at therapeutic doses at the tumor vascular level. To evaluate the therapeutic effects of L19-IL2 and L19mTNFalpha in neuroblastoma (NB)-bearing mice, A/J mice bearing Neuro2A or NIE115 NB were systemically treated with L19-IL2 and L19mTNFalpha, alone or in combination protocols. Seventy percent of Neuro2A- and 30% of NIE115-bearing mice were cured by the combined treatment with L19-IL2 and L19mTNFalpha, and further rejected a homologous tumor challenge, indicating specific antitumor immune memory. The immunological bases of tumor cure and rejection were studied. A highly efficient priming of CD4(+) T helper cells and CD8(+) CTL effectors was generated, paralleled by massive infiltration in the tumor tissue of CD4(+) and CD8(+) T cells at day 16 after tumor cell implantation, when, after therapy, tumor volume was drastically reduced and tumor necrosis reached about 80%. The curative treatment resulted in a long-lasting antitumor immune memory, accompanied by a mixed Th1/Th2 type of response. Concluding, L19-IL2 and L19mTNFalpha efficiently cooperate in determining a high percentage of NB cure that, in our experimental models, is strongly associated to the generation of adaptive immunity involving CD4(+) and CD8(+) T cells.

Increasing the endothelial layer permeability through ultrasound-activated microbubbles

Drug delivery to a diseased tissue will be more efficient if the vascular endothelial permeability is increased. Recent studies have shown that the permeability of single cell membranes is increased by ultrasound in combination with contrast agents. It is not known whether this combination can also increase the permeability of an endothelial layer in the absence of cell damage. To investigate the feasibility of controlled increased endothelial layer permeability, we treated monolayers of human umbilical vein endothelial cells with ultrasound and the contrast agent BR14. Barrier function was assessed by measuring transendothelial electrical resistance (TEER). Ultrasound-activated BR14 significantly decreased TEER by 40.3% +/- 3.7% ( p < 0.01). After treatment, no cell detachment or damage was observed. In conclusion, ultrasound-activated BR14 microbubbles increased the endothelial layer permeability. This feature can be used for future ultrasound-guided drug delivery systems.

Improving TNF as a cancer therapeutic: tailor-made TNF fusion proteins with conserved antitumor activity and reduced systemic side effects

Tumor necrosis factor (TNF) is highly pleiotropic cytokine regulating diverse cellular processes such as proliferation, cell migration, angiogenesis, differentiation, apoptosis, necrosis, but also survival. Because of its name-giving tumor necrosis-inducing capabilities, TNF has attracted attention very early for antitumor therapy. Although TNF is in clinical use for treatment of soft tissue sarcoma in isolated limb perfusion, its broad use in tumor therapy is prevented so far by its strong systemic proinflammatory effects. Nevertheless, over the past decade, a variety of tailor-made TNF variants have been developed with the aim to reduce TNFs systemic activity without losing its antitumoral effects. Here, we review the progress made toward improving the efficacy of TNF by genetic engineering, tumor targeting, and introduction of prodrug concepts.

Revisiting perioperative chemotherapy: the critical importance of targeting residual cancer prior to wound healing

BACKGROUND

Scientists and physicians have long noted similarities between the general behavior of a cancerous tumor and the physiological process of wound healing. But it may be during metastasis that the parallels between cancer and wound healing are most pronounced. And more particularly and for the reasons detailed in this paper, any cancer remaining after the removal of a solid tumor, whether found in micrometastatic deposits in the stroma or within the circulation, may be heavily dependent on wound healing pathways for its further survival and proliferation.

DISCUSSION

If cancer cells can hijack the wound healing process to facilitate their metastatic spread and survival, then the period immediately after surgery may be a particularly vulnerable period of time for the host, as wound healing pathways are activated and amplified after the primary tumor is removed. Given that we often wait 30 days or more after surgical removal of the primary tumor before initiating adjuvant chemotherapy to allow time for the wound to heal, this paper challenges the wisdom of that clinical paradigm, providing a theoretical rationale for administering therapy during the perioperative period.

SUMMARY

Waiting for wound healing to occur before initiating adjuvant therapies may be seriously compromising their effectiveness, and patients subsequently rendered incurable as a result of this wait. Clinical trials to establish the safety and effectiveness of administering adjuvant therapies perioperatively are needed. These therapies should target not only the residual cancer cells, but also the wound healing pathway utilized by these cells to proliferate and metastasize.

TNF-alpha and its inhibitors in cancer

Tumor necrosis factor (TNF)-alpha is implicated in the same time in apoptosis and in cell proliferation. TNF-alpha not only acts as pro-inflammatory cytokine conducing to wide spectrum of human diseases including inflammatory diseases, but can also induce tumor development. The molecular mechanisms of TNF-alpha functions have been intensively investigated. In this review we covered TNF-alpha, the molecule, its signaling pathway, and its therapeutic functions. We provide a particular insight in its paradoxical role in tumor promotion and in its use as anti-tumor agent. This review considers also the recent findings regarding TNF-alpha inhibitors, their pharmacokinetics, and their pharmacodynamics. Six TNF-alpha inhibitors have been considered here: Infliximab, Adalimumab, Golimumab, CDP870, CDP571, Etanercept, and Thalidomide. We discussed the clinical relevance of their functions in treatment of several diseases such as advanced inflammatory rheumatic and bowel disease, with a focus in cancer treatment. Targeting TNF-alpha by these drugs has many side effects like malignancies development, and the long-term sequels are not very well explored. Their efficacy and their safety were discussed, underscoring the necessity of close patients monitoring and of their caution use.