[On a hypothetic model based on the involvement of the immune system in the cells proliferation and metastasization of tumors]

Tumor cells lose their capability of self-destruction at the hazard of their transformation; they are actually immortal. The macrophages phagocyting the oncogenous cell (its nucleus or fragment) may not manage to destroy it. Under such conditions, the transformation of the macrophage itself into the oncogenous cell could not be ruled out. In the present work, a new hypothesis for the participation of the immune system in the metastasization of tumors is proposed. The extensive investigation of this mechanism would help to find new ways of cancer forecast and treatment.

Transcription factor Egr-1 is essential for maximal matrix metalloproteinase-9 transcription by tumor necrosis factor alpha

Matrix metalloproteinase-9 (MMP-9) is involved in a wide range of normal and pathologic conditions, including inflammation, tissue repair, tumor invasion, and metastasis. Tumor necrosis factor alpha (TNFalpha) is a major proinflammatory cytokine that plays crucial roles in tumor progression, including tumor invasion and metastasis in the tumor microenvironment. Egr-1 is a member of the zinc-finger transcription factor family induced by diverse stimuli, including TNFalpha. However, the role of Egr-1 in MMP-9 expression was previously unknown. This study shows that Egr-1 directly binds to the MMP-9 promoter and plays an essential role for TNFalpha induction of MMP-9 transcription. Furthermore, Egr-1 together with NF-kappaB can synergistically activate both basal and TNFalpha-induced MMP-9 promoter activities in the presence of p300. We found that Egr-1 mediates extracellular signal-regulated kinase and c-jun NH(2)-terminal kinase mitogen-activated protein kinase-dependent MMP-9 transcription on TNFalpha stimulation. The requirement for Egr-1 in MMP-9 expression is further supported by the fact that HeLa cells expressing Egr-1 siRNA and Egr-1-null mouse embryonic fibroblasts were refractory to TNFalpha-induced MMP-9 expression. This report establishes that Egr-1 is essential for MMP-9 transcription in response to TNFalpha within the tumor microenvironment.

Targeting activated integrin alphavbeta3 with patient-derived antibodies impacts late-stage multiorgan metastasis

Advanced metastatic disease is difficult to manage and specific therapeutic targets are rare. We showed earlier that metastatic breast cancer cells use the activated conformer of adhesion receptor integrin alphavbeta3 for dissemination. We now investigated if targeting this form of the receptor can impact advanced metastatic disease, and we analyzed the mechanisms involved. Treatment of advanced multi-organ metastasis in SCID mice with patient-derived scFv antibodies specific for activated integrin alphavbeta3 caused stagnation and regression of metastatic growth. The antibodies specifically localized to tumor lesions in vivo and inhibited alphavbeta3 ligand binding at nanomolar levels in vitro. At the cellular level, the scFs associated rapidly with high affinity alphavbeta3 and dissociated extremely slowly. Thus, the scFvs occupy the receptor on metastatic tumor cells for prolonged periods of time, allowing for inhibition of established cell interaction with natural alphavbeta3 ligands. Potential apoptosis inducing effects of the antibodies through interaction with caspase-3 were studied as potential additional mechanism of treatment response. However, in contrast to a previous concept, neither the RGD-containing ligand mimetic scFvs nor RGD peptides bound or activated caspase-3 at the cellular or molecular level. This indicates that the treatment effects seen in the animal model are primarily due to antibody interference with alphavbeta3 ligation. Inhibition of advanced metastatic disease by treatment with cancer patient derived single chain antibodies against the activated conformer of integrin alphavbeta3 identifies this form of the receptor as a suitable target for therapy.

Relationship between psychoncology and psychoneuroendocrinoimmunology (PNEI): enhanced T-regulatory lymphocyte activity in cancer patients with self-punishement, evaluated by Rorschach test

BACKGROUND

Psychological studies have documented the presence of a self-punishment profile in cancer patients. Recent immuno-oncological studies have shown that within the group of CD4(+) cells, which play a fundamental role in the generation of anticancer immunity, there is a subtype of cells that in contrast mediates the suppression of the anticancer immunity, the so-called T-regulatory cells (T-reg), which may be identified as CD4(+)CD25(+) cells.

PATIENTS AND METHODS

On this basis, we performed a psychoncological study to evaluate CD4(+)CD25(+) cell numbers in relation to the response to Rorschach's test in a group of 30 cancer patients suffering from the most frequent tumor histotypes.

RESULTS

Normal values obtained in our laboratory (95% confidence limits) of T-reg lymphocytes and CD4(+)/CD4(+)CD25(+) were <240/mm(3) and >4mm(3), respectively. The psychological profile of self-punishment was found in 18/30 patients (60%). The percentage of patients with abnormally high CD4(+)CD25(+) values observed in the group with self-punishment was significantly higher than that found in patients without self punishment (11/18 vs. 3/12 (25%), p<0.05). In the same way, the percentage of patients with abnormally low CD4(+)/CD4(+)CD25(+) ratios was significantly higher in the group with self-punishment (16/18 vs. 4/12, p<0.01). The mean numbers of T-reg lymphocytes observed in the group with self-punishment was significantly higher than that found in patients who had no self-punishment (314+/-39 vs. 173+/-27, p<0.05). In addition, the mean CD4(+)/ CD4(+)CD25(+) ratio was significantly lower in patients with self-punishment than in the other group (2.6+/-0.2 vs. 5.2+/-0.8, p<0.025). On the contrary, no significant difference was seen in the mean number of CD4(+) lymphocytes.

CONCLUSION

The study suggests that self-punishment may inhibit the generation of an effective anticancer immune response by stimulating the activation and proliferation of T-reg lymphocytes, which in turn stimulate tumor dissemination by suppressing anticancer immunity. The abnormally high number of T-reg lymphocytes in patients with self-punishment would suggest a specific immune alteration, as suggested by the evidence of a normal profile for other immune parameters, such as total CD4(+) lymphocytes.

A distinct macrophage population mediates metastatic breast cancer cell extravasation, establishment and growth

Background

The stromal microenvironment and particularly the macrophage component of primary tumors influence their malignant potential. However, at the metastatic site the role of these cells and their mechanism of actions for establishment and growth of metastases remain largely unknown.

Methodology/Principal Findings

Using animal models of breast cancer metastasis, we show that a population of host macrophages displaying a distinct phenotype is recruited to extravasating pulmonary metastatic cells regardless of species of origin. Ablation of this macrophage population through three independent means (genetic and chemical) showed that these macrophages are required for efficient metastatic seeding and growth. Importantly, even after metastatic growth is established, ablation of this macrophage population inhibited subsequent growth. Furthermore, imaging of intact lungs revealed that macrophages are required for efficient tumor cell extravasation.

Conclusion/Significance

These data indicate a direct enhancement of metastatic growth by macrophages through their effects on tumor cell extravasation, survival and subsequent growth and identifies these cells as a new therapeutic target for treatment of metastatic disease.

Effects of anesthetics and analgesics on natural killer cell activity

Surgical excision of cancerous tumors and the human stress response can lead to metastasis of tumor cells. Furthermore, the medications used during the perioperative period (eg, opioids and anesthetic agents) have been shown to inhibit or suppress natural killer (NK) cell activity, one of the body's main defenses against spread of cancer. There are currently no anesthetic regimens that have been shown to completely reverse surgical stress-induced suppression of NK cell activity. However, there may be anesthetic techniques that attenuate surgical suppression of NK cell activity. This article reviews the effects of various anesthetics and analgesics on NK cell activity and suggests techniques to attenuate the suppressive effects of these compounds.

The HLA-A2-restricted PSMA peptide LLHETDSAV is poorly immunogenic in patients with metastatic prostate cancer

BACKGROUND

Increasing evidence suggests that prostate cancer is visible to the immune system and is potentially responsive to immunotherapeutic interventions. Previous work has identified prostate-specific membrane antigen (PSMA) as a potential antigen for T-cell recognition, and specific PSMA epitopes presented by HLA-A2 have been described. One vaccination strategy that is being pursued in the clinic utilizes peptide-pulsed peripheral blood mononuclear cells (PBMC) + IL-12.

METHODS

HLA-A2(+) patients with castrate-resistant prostate cancer and normal organ function were considered. Vaccines were prepared using autologous PBMC loaded with a PSMA peptide previously reported to be immunogenic (LLHETDSAV) administered subcutaneously every 3 weeks. T-cell responses and tumor activity were assessed.

RESULTS

Although the vaccine was well tolerated, no clinical responses were observed in 12 enrolled patients and no immune responses were detected based on an ex vivo IFN-gamma ELISPOT assay. To examine immunogenicity of this PSMA peptide in more detail, an in vitro priming assay was utilized with normal donor PBMC, and no detectable reactivity was observed.

CONCLUSIONS

Our results suggest that the PSMA peptide LLHETDSAV is poorly immunogenic in humans and that alternative prostate cancer antigens should be pursued.

[Is it possible to correct the anergy of T lymphocytes that infiltrate tumors?]

Human tumor metastases are often infiltrated by T lymphocytes that are specific for tumor antigens, but these metastases progress anyway. The spontaneous anti-tumor immune response seems thus to become ineffective, probably because the effector T cells become anergic. This anergy could result from inhibitory mechanisms orchestrated by the tumor cells. We have observed that recently stimulated human cytolytic T cell clones lose transiently their capacity to secrete cytokines. This anergy is correlated with the absence of colocalization of the T cell receptors (TCR) and the CD8 co-receptors. Effector functions' and TCR/CD8 colocalization are recovered by treating cells with galectin-3 ligands, suggesting that exracellular galectin-3 forms glycoprotein-galectin lattices, which decrease the TCR mobility on the surface of anergic T lymphocytes. Galectin-3 is frequently released by tumor cells. This new mechanism of anergy could thus also explain the loss of functions of the tumor-infiltrating lymphocytes, because these lymphocytes recover their effector functions and TCR/CD8 colocalization after ex vivo treatment with galectin-3 ligands. These results could lead to new therapeutical strategies.

Immune, endocrine, and behavioral precursors to breast cancer recurrence: a case-control analysis

BACKGROUND

A period of tumor growth precedes the clinical detection of breast cancer recurrence. We explore immune, endocrine, and behavioral parameters during this period.

METHODS

We conducted a phase III clinical trial in which women with surgically treated stage II/III breast cancer (N = 227) were randomized to receive a psychological intervention or assessment-only and then regularly assessed for 10 years. Patients who recurred (R, n = 48) were matched with patients remaining disease-free (DF, n = 48) on demographic and prognostic characteristics, treatment, and duration of disease-free follow-up. Data at three assessment points, occurring, on average, 17, 11, and 4 months before the recurrence was detected clinically, with equivalent time points for the disease-free group, were examined. Mixed-effects models tested for group differences in immune cell counts and function as well as endocrine and behavioral parameters.

RESULTS

In the 17 months prior to recurrence detection, patients exhibited higher white blood cell count, neutrophil, lymphocyte, and natural killer cell counts, relative to DF patients. R patients also showed higher cortisol, worse physical functioning, fatigue, and quality of life. Follow-up analyses showed patients with local recurrences to differ from those with distant recurrence, with the former exhibiting elevated natural killer cell cytotoxicity, lymphocyte proliferative response, fatigue, pain, and emotional distress (depression, anxiety), and the latter exhibiting higher neutrophil, lymphocyte, and natural killer cell counts.

CONCLUSION

Patients who would recur showed reliable biobehavioral alterations more than a year prior to their diagnosis. This novel observation may contribute to our understanding of the disease relapse processes.

Immune cells as mediators of solid tumor metastasis

Outgrowths of disseminated metastases remain the primary cause of mortality in cancer patients; however, molecular and cellular mechanisms regulating metastatic spread remain largely elusive. Recent insights into these mechanisms have refined the seed and soil hypothesis and it is now recognized that metastasis of solid tumors requires collaborative interactions between malignant cells and a diverse assortment of "activated" stromal cells at both primary and secondary tumor locations. Specifically, persistent pro-tumor immune responses (inflammation), now generally accepted as potentiating primary tumor development, are also being recognized as mediators of cancer metastasis. Thus, novel anti-cancer therapeutic strategies targeting molecular and/or cellular mechanisms regulating these collaborative interactions may provide efficacious relief for metastatic disease. This review focuses on recent literature revealing new mechanisms whereby immune cells regulate metastatic progression, with a primary focus on breast cancer.

Review: anti-CTLA-4 antibody ipilimumab: case studies of clinical response and immune-related adverse events

The immune system is a powerful natural agent against cancer. Cytotoxic T lymphocyte antigen 4 (CTLA-4), a key negative regulator of T-cell responses, can restrict the antitumor immune response. Ipilimumab (MDX-010) is a fully human, monoclonal antibody that overcomes CTLA-4-mediated T-cell suppression to enhance the immune response against tumors. Preclinical and early clinical studies of patients with advanced melanoma show that ipilimumab promotes antitumor activity as monotherapy and in combination with treatments such as chemotherapy, vaccines, or cytokines. Emerging data on the kinetics of response to ipilimumab and associated adverse events are increasing our understanding about how to manage patients treated with this therapy. For example, short-term tumor progression prior to delayed regression has been observed in ipilimumab-treated patients, and objective responses may be of prolonged duration. In some patients clinical improvement manifests as stable disease, which may also extend for months or years. Immune-related adverse events (IRAEs) have been observed in patients after CTLA-4 blockade and most likely reflect the drug mechanism of action and corresponding effects on the immune system. Early clinical data suggest a correlation between IRAEs and response to ipilimumab treatment. This paper briefly reviews the results from several ongoing and completed ipilimumab clinical trials, provides a synopsis of current trials, and presents several cases that demonstrate the kinetics of antitumor responses and the relationship to IRAEs in patients receiving ipilimumab.

[Serum anti-p53 antibodies and CEA in monitoring of recurrences of colorectal cancer]

INTRODUCTION

Little is known regarding the behaviour of serum anti-p53 antibodies (p53 Ab) in postoperative follow-up of patients with colorectal carcinoma and whether it can be used as an additional marker. The aim of this study was to evaluate usefulness of p53 Ab and CEA level for postoperative monitoring of recurrence or metastasis in patients after surgery due to colorectal cancer with normal pre-operative CEA levels and anti-p53 anitbodies.

MATERIAL AND METHODS

The research group consisted of 124 patients with colorectal cancer diagnosed on the basis of histopathological or cytological examination. Colonoscopy, abdominal ultrasound, serum CEA and anti-p53 antibody tests were done at the time of diagnosis and every 6-month from surgery.

RESULTS

The occurrence of recurrence or metastasis was preceded by the appearance of anti-p53 antibodies 6 months earlier on average, in 5 patients, and the increased CEA level was preceded 9 months earlier on average, in 7 patients. The relationship between the increased CEA level and the occurrence of recurrence or metastasis was statistically significant (p < 0.0001); however statistically significant relationship was not found in the case of anti-p53 antibodies assessment. Performing these two tests simultaneously, at the same time with the same patients caused the increase of accuracy of recurrence or metastasis from 0.45 to 0.68.

CONCLUSION

Multiple assessments of both serum p53 Ab and CEA during postoperative monitoring increase the probability of early detection of recurrence or metastasis in patients with colorectal cancer and normal CEA level before surgery.

Efficacy and safety of intravenous immunoglobulin in patients with metastatic melanoma

We have previously reported studies performed both in vitro and in laboratory animals, as well as a case study in humans, suggesting that intravenous immunoglobulin (IVIG) may be beneficial in the treatment of malignancies, including metastatic melanoma. As part of a phase II open label trial, we have administered IVIG to nine patients with metastatic melanoma who had been heavily treated. In two of nine (22%) patients treated every 3 weeks with IVIG (1 g/kg body weight), the disease stabilized. One patient had stable disease for 8 months; the other for 3 months. No serious adverse events (AEs) attributable to IVIG were observed. We conclude that IVIG therapy may be useful for the treatment of metastatic melanoma. Furthermore, we suggest that the effects of IVIG therapy might be enhanced by its use as an adjuvant in patients without evidence of disease following surgery.

Immunotherapy of advanced or metastatic melanoma

Melanoma is often evaluated for the development of anticancer immunotherapeutics. Fascinating immune and clinical responses in small numbers of patients have prompted various approaches, ranging from nonspecific immune stimulation to therapies that target specific antigens. Unfortunately, these immune therapies have often shown limited success and objective responses have been seen in only a modest subset of patients. The challenge has been to identify factors that can lead to more consistent clinical benefit and to develop strategies to overcome the obstacles to successful antitumor immunity. Over the last 15 years many immune targets have been identified in cancers and the mechanisms underpinning clinical responses have become better understood. Furthermore, new ways to manipulate anticancer immunity are making it possible to overcome cancer immune evasion and subversion. New therapeutic strategies are resulting from these emerging insights into the relationship between melanoma and the host immune response.

Administration of a CD25-directed immunotoxin, LMB-2, to patients with metastatic melanoma induces a selective partial reduction in regulatory T cells in vivo

CD25+ CD4+ T regulatory (Treg) cells regulate peripheral self tolerance and possess the ability to suppress antitumor responses, which may in part explain the poor clinical response of cancer patients undergoing active immunization protocols. We have previously shown that in vitro incubation of human PBMC with LMB-2, a CD25-directed immunotoxin, significantly reduced CD25+ FOXP3+ CD4+ Treg cells without impairing the function of the remaining lymphocytes. In the current study, eight patients with metastatic melanoma were treated with LMB-2 followed by MART-1 and gp100-specific peptide vaccination. LMB-2 administration resulted in a preferential, transient reduction in mean circulating CD25+ CD4+ T cell number, from 83 +/- 16 cells/microl to a nadir of 17 +/- 5 cells/microl, a 79.1% reduction. FOXP3 analysis revealed a less robust depletion with mean FOXP3+ CD4+ Treg cell number decreasing from 74 +/- 15 cells/microl to 36 +/- 8 cells/microl, a 51.4% reduction. FOXP3+ CD4+ Treg cells that survived LMB-2-mediated cytotoxicity expressed little or no CD25. Similar to the peripheral blood, immunohistochemical analysis showed a 68.9% mean reduction in FOXP3+ CD4+ Treg cell frequency in evaluable lesions. Despite inducing a reduction in Treg cell numbers in vivo, LMB-2 therapy did not augment the immune response to cancer vaccination and no patient experienced an objective response or autoimmunity. These data demonstrate the capacity of a CD25-directed immunotoxin to selectively mediate a transient partial reduction in circulating and tumor-infiltrating Treg cells in vivo, and suggest that more comprehensive Treg cell elimination may be required to bolster antitumor responses in patients with metastatic melanoma.

Human NK cell infusions prolong survival of metastatic human neuroblastoma-bearing NOD/scid mice

AIM

Several lines of evidence suggest that NK cell immunotherapy may represent a successful approach in neuroblastoma (NB) patients refractory to conventional therapy. However, homing properties, safety and therapeutic efficacy of NK cell infusions need to be evaluated in a suitable preclinical murine NB model.

MATERIALS AND METHODS

Here, the therapeutic efficacy of NK cell infusions in the presence or absence of NK-activating cytokines have been evaluated in a NB metastatic model set up in NOD/scid mice, that display reduced functional activity of endogenous NK cells.

RESULTS

In NOD/scid mice the injected NB cells rapidly reached all the typical sites of metastatization, including bone marrow. Infusion of polyclonal IL2-activated NK cells was followed by dissemination of these cells into various tissues including those colonized by metastatic NB cells. The early repeated injection of IL2-activated NK cells in NB-bearing NOD/scid mice significantly increased the mean survival time, which was associated with a reduced bone marrow infiltration. The therapeutic effect was further enhanced by low doses of human recombinant IL2 or IL15.

CONCLUSION

Our results indicate that NK-based adoptive immunotherapy can represent a valuable adjuvant in the treatment of properly selected NB patients presenting with metastatic disease, if performed in a minimal residual disease setting.

T cells are crucial for the anti-metastatic effect of anti-epidermal growth factor receptor antibodies

Experimental evidences supporting the epidermal growth factor receptor (EGFR) as an important molecule for tumor metastasis had been accumulated. Currently, anti-EGFR monoclonal antibodies (mAbs) constitute a promising approach for the treatment of patients with metastatic tumors. However, the mechanisms associated with the potent anti-metastatic effect of these mAbs have not been completely elucidated due to the lack of appropriate syngeneic preclinical models. In this paper, we have investigated the effects of 7A7, an antibody specific to murine EGFR, on the metastatic properties of D122 murine lung carcinoma. 7A7 mAb significantly impaired metastatic spread of D122 cells in C57BL/6 mice by direct anti-proliferative and pro-apoptotic effects on tumor metastasis. 7A7 mAb capacity to inhibit EGFR activation on D122 cells could contribute to its anti-metastatic effect. In addition, 7A7 mAb was able to induce in vitro antibody-dependent cell-mediated cytotoxicity on D122 cells. Interestingly, 7A7 mAb treatment increased the number of natural killer cells, T lymphocytes and dendritic cells infiltrating the metastatic sites. More strikingly, depletion of CD8(+) and CD4(+) T cells in vivo completely abrogated the 7A7 mAb anti-metastatic activity whereas function of natural killer cells was irrelevant. This study supports an in vivo role for T cell response in the mechanism of action of anti-EGFR mAbs, suggesting the induction of an adjuvant effect.

Modulation of cell-mediated immune response in B16F-10 melanoma-induced metastatic tumor-bearing C57BL/6 mice by sulforaphane

Effect of sulforaphane on cell-mediated immune response (CMI) was studied in B16F-10 melanoma-induced metastasis-bearing C57BL/6 mice. Administration of sulforaphane significantly enhanced natural killer (NK) cell activity in metastatic tumor-bearing animals (43.17% cell lysis, on day 5) and the activity was observed earlier than in tumor-bearing control animals (maximum of 9.76% cell lysis, on day 9). Antibody-dependent cellular cytotoxicity also was enhanced significantly in metastatic tumor-bearing animals (41.20% cell lysis on day 9) after sulforaphane administration compared with untreated control tumor-bearing animals (maximum of 12.62% cell lysis on day 15). An early antibody-dependent complement-mediated cytotoxicity also was observed in sulforaphane-treated tumor-bearing animals (26% cell lysis, on day 15). Administration of sulforaphane significantly enhanced the production of IL-2 and IFN-gamma in metastatic tumor-bearing animals. In addition, sulforaphane significantly downregulated the serum levels of proinflammatory cytokines such as IL-1beta, IL-6, TNF-alpha, and GM-CSF during metastasis. These data clearly suggest that sulforaphane effectively inhibited the spread of metastatic tumor cells through the stimulation of CMI, upregulation of IL-2 and IFN-gamma, and downregulation of proinflammatory cytokines IL-1beta, IL-6, TNF-alpha, and GM-CSF.

Metastatic breast cancer induces an osteoblast inflammatory response

Breast cancer preferentially metastasizes to the skeleton, a hospitable environment that attracts and allows breast cancer cells to thrive. Growth factors released as bone is degraded support tumor cell growth, and establish a cycle favoring continued bone degradation. While the osteoclasts are the direct effectors of bone degradation, we found that osteoblasts also contribute to bone loss. Osteoblasts are more than intermediaries between tumor cells and osteoclasts. We have presented evidence that osteoblasts contribute through loss of function induced by metastatic breast cancer cells. Metastatic breast cancer cells suppress osteoblast differentiation, alter morphology, and increase apoptosis. In this study we show that osteoblasts undergo an inflammatory stress response in the presence of human metastatic breast cancer cells. When conditioned medium from cancer cells was added to human osteoblasts, the osteoblasts were induced to express increased levels of IL-6, IL-8, and MCP-1; cytokines known to attract, differentiate, and activate osteoclasts. Similar findings were seen with murine osteoblasts and primary murine calvarial osteoblasts. Osteoblasts are co-opted into creating a microenvironment that exacerbates bone loss and are prevented from producing matrix proteins for mineralization. This is the first study implicating osteoblast produced IL-6, IL-8 (human; MIP-2 and KC mouse), and MCP-1 as key mediators in the osteoblast response to metastatic breast cancer cells.