Where have all the T cells gone? Mechanisms of immune evasion by tumors

The role of tumor-associated macrophages (TAMs) in tumor progression and relevant advance in targeted therapy

Macrophages have a leading position in the tumor microenvironment (TME) which paves the way to carcinogenesis. Initially, monocytes and macrophages are recruited to the sites where the tumor develops. Under the guidance of different microenvironmental signals, macrophages would polarize into two functional phenotypes, named as classically activated macrophages (M1) and alternatively activated macrophages (M2). Contrary to the anti-tumor effect of M1, M2 exerts anti-inflammatory and tumorigenic characters. In progressive tumor, M2 tumor-associated macrophages (TAMs) are in the majority, being vital regulators reacting upon TME. This review elaborates on the role of TAMs in tumor progression. Furthermore, prospective macrophage-focused therapeutic strategies, including drugs not only in clinical trials but also at primary research stages, are summarized followed by a discussion about their clinical application values. Nanoparticulate systems with efficient drug delivery and improved antitumor effect are also summed up in this article.

Contemporary treatment of metastatic renal cell carcinoma

Renal cell carcinoma is the 14th most common cancer worldwide. It is a heterogeneous group of histopathological entities, of which the most common is clear cell renal cell carcinoma. Approximately 20-30% of patients present initially with metastatic disease and an additional 20% will progress after radical surgical treatment. Metastatic disease that is non-feasible for surgical treatment remains incurable. Numerous studies have demonstrated that-with the introduction of new drugs-the treatment outcomes of metastatic disease have improved. The development of new therapies as well as the optimization and individualization of procedures allow us to hope for further progress in this area.

Tyrosine kinase inhibitors reprogramming immunity in renal cell carcinoma: rethinking cancer immunotherapy

The immune system regulates angiogenesis in cancer by way of both pro- and antiangiogenic activities. A bidirectional link between angiogenesis and the immune system has been clearly demonstrated. Most antiangiogenic molecules do not inhibit only VEGF signaling pathways but also other pathways which may affect immune system. Understanding of the role of these pathways in the regulation of immunosuppressive mechanisms by way of specific inhibitors is growing. Renal cell carcinoma (RCC) is an immunogenic tumor in which angiogenesis and immunosuppression work hand in hand, and its growth is associated with impaired antitumor immunity. Given the antitumor activity of selected TKIs in metastatic RCC (mRCC), it seems relevant to assess their effect on the immune system. The confirmation that TKIs improve cell cytokine response in mRCC provides a basis for the rational combination and sequential treatment of TKIs and immunotherapy.

GBM Derived Gangliosides Induce T Cell Apoptosis through Activation of the Caspase Cascade Involving Both the Extrinsic and the Intrinsic Pathway

Previously we demonstrated that human glioblastoma cell lines induce apoptosis in peripheral blood T cells through partial involvement of secreted gangliosides. Here we show that GBM-derived gangliosides induce apoptosis through involvement of the TNF receptor and activation of the caspase cascade. Culturing T lymphocytes with GBM cell line derived gangliosides (10-20μg/ml) demonstrated increased ROS production as early as 18 hrs as indicated by increased uptake of the dye H₂DCFDA while western blotting demonstrated mitochondrial damage as evident by cleavage of Bid to t-Bid and by the release of cytochrome-c into the cytosol. Within 48-72 hrs apoptosis was evident by nuclear blebbing, trypan blue positivity and annexinV/7AAD staining. GBM-ganglioside induced activation of the effector caspase-3 along with both initiator caspases (-9 and -8) in T cells while both the caspase-8 and -9 inhibitors were equally effective in blocking apoptosis (60% protection) confirming the role of caspases in the apoptotic process. Ganglioside-induced T cell apoptosis did not involve production of TNF-α since anti-human TNFα antibody was unable to protect T cells from nuclear blebbing and subsequent cell death. However, confocal microscopy demonstrated co-localization of GM2 ganglioside with the TNF receptor and co-immunoprecipitation experiments showed recruitment of death domains FADD and TRADD with the TNF receptor post ganglioside treatment, suggesting direct interaction of gangliosides with the TNF receptor. Further confirmation of the interaction between GM2 and TNFR1 was obtained from confocal microscopy data with wild type and TNFR1 KO (TALEN mediated) Jurkat cells, which clearly demonstrated co-localization of GM2 and TNFR1 in the wild type cells but not in the TNFR1 KO clones. Thus, GBM-ganglioside can mediate T cell apoptosis by interacting with the TNF receptor followed by activation of both the extrinsic and the intrinsic pathway of caspases.

Disease relevance of T11TS-induced T-cell signal transduction through the CD2-mediated calcineurin-NFAT pathway: Perspectives in glioma immunotherapy

Malignant glioma is the most lethal of a wide array of CNS neoplasms. Its onset and progression are markedly associated with profound immunosupression and paralysis of T-cell survival and proliferation. Myriad immunotherapeutic strategies are presently used to target such T-cell anomalies in glioma. Our recent work has highlighted use of the novel glycopeptide, the CD2 ligand, T11 target structure (T11TS) as an immunotherapeutic agent against experimentally induced glioma in rats. We have shown that T11TS causes multi-target modulation of key components of the T-cell - antigen presenting cell (APC) immunological synapse. This consequently triggers T-cell activation so as to reverse glioma-induced changes to physiological levels. T11TS administration also causes CD2 upregulation. Earlier we also found T11TS to cause enhanced proliferation of both CD4+ and CD8+ T-cells in glioma conditions. These findings led us to believe that downstream CD2-stimulated "alternative pathway" of calcineurin-NFAT could be a possible target for modulation by T11TS. In the present paper we thus show that immunotherapy with T11TS induces a multi-targeted approach towards activation of this "alternative pathway" of T-cell signaling providing an immunotherapeutic advantage against glioma. We show here that T11TS immunotherapy causes positive modulations of the CD2 pathway-associated proteins, viz., p59fyn, protein kinase C-θ (PKC-θ), calcineurin and nuclear factor for activation of T-cells (NFAT) and hint that this may accord greater survival and proliferation advantage to T-cells of the glioma-bearing animals for augmented defence against glioma. These findings help open a molecular immunotherapeutic door - one which is directed towards clinical studies for glioma-immunotherapy using T11TS.

Antitumor immunostimulatory activity of polysaccharides from Salvia chinensis Benth

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia chinensis Benth (S. chinensis) is a traditional herb applied in the treatment of hepatocellular carcinoma (HCC). Polysaccharides abundantly exist in this plant. However, it remains poorly understood if polysaccharides from S. chinensis (PSSC) contribute to its anti-HCC activity.

MATERIALS AND METHODS

The in vivo anti-HCC activity of PSSC was evaluated in Kunming mice bearing H22 ascitic hepatoma cells. An array of physiological indexes was measured to evaluate toxicological effects on host animals. Subgroups of immune cells were purified by a magnetic-activated cell sorting system and analyzed by flow cytometry. Reverse transcription real-time PCR and immunoblotting were recruited to determine the effects of PSSC on the cellular signaling of different subgroup of immune cells.

RESULTS

PSSC suppressed in vivo proliferation of H22 cells with undetectable toxic effects on tumor-bearing mice. PSSC alleviated tumor transplantation-induced CD4+ T cell apoptosis and dysregulation of serum cytokine profiles, which elevated cytotoxic activities of natural killer and CD8+ T cells. PSSC reduced serum levels of prostaglandin E2 (PGE2). Injection of exogenous PGE2 completely abrogated the antitumor immunostimulatory activity of PSSC. Cyclic adenosine monophosphate (cAMP) is the second messager of PGE2. In CD4+ T cells, PSSC substantially declined intracellular cAMP. This event elevated protein levels of JAK3, enhancing STAT5 phosphorylation and STAT5-dependent expression of anti-apoptotic genes. Cyclooxygenase-2 is the key enzyme mediating biosynthesis of PGE2. PSSC suppressed the transcription and translation of cyclooxygenase-2 in tumor associated macrophages.

CONCLUSION

Our data clearly showed antitumor immunostimulatory activity of PSSC against transplanted H22 HCC cells. Suppressing tumor transplantation-induced PGE2 production was implicated in the anti-tumor immunostimulatory activity of PSSC. These works provides novel insights into the traditional application of S. chinensis against HCC and supported considering PSSC as an adjuvant reagent in clinical HCC treatment.

Chemical compounds from anthropogenic environment and immune evasion mechanisms: potential interactions

An increasing number of studies suggest an important role of host immunity as a barrier to tumor formation and progression. Complex mechanisms and multiple pathways are involved in evading innate and adaptive immune responses, with a broad spectrum of chemicals displaying the potential to adversely influence immunosurveillance. The evaluation of the cumulative effects of low-dose exposures from the occupational and natural environment, especially if multiple chemicals target the same gene(s) or pathway(s), is a challenge. We reviewed common environmental chemicals and discussed their potential effects on immunosurveillance. Our overarching objective was to review related signaling pathways influencing immune surveillance such as the pathways involving PI3K/Akt, chemokines, TGF-β, FAK, IGF-1, HIF-1α, IL-6, IL-1α, CTLA-4 and PD-1/PDL-1 could individually or collectively impact immunosurveillance. A number of chemicals that are common in the anthropogenic environment such as fungicides (maneb, fluoxastrobin and pyroclostrobin), herbicides (atrazine), insecticides (pyridaben and azamethiphos), the components of personal care products (triclosan and bisphenol A) and diethylhexylphthalate with pathways critical to tumor immunosurveillance. At this time, these chemicals are not recognized as human carcinogens; however, it is known that they these chemicalscan simultaneously persist in the environment and appear to have some potential interfere with the host immune response, therefore potentially contributing to promotion interacting with of immune evasion mechanisms, and promoting subsequent tumor growth and progression.

[Locoregional surgery for stage IV breast cancer patients]

Three to 6% of women newly diagnosed with breast cancers have stage IV disease. Overall survival was improved during the last few years (16-45 months). The treatment of stage IV breast cancer has traditionally been palliative with surgical resection reserved for symptomatic wound complications. Since 2000, several retrospective studies have compared surgery versus no local therapy in women presenting with stage IV breast cancer with an intact primary tumor. All showed a survival advantage for the surgical cohort. However, these studies are limited by the fact that it is not possible to control for biases that led to surgical resection of the primary tumor. Several prospective randomized trials have been undertaken. We have partial results for two of them and they show no survival differences between patients who benefit from local surgery and patients who did not have surgery. However, breast surgery is at low risk of complication, if not considering psychological aspect of mastectomy, and can be proposed to patients with no progression after first chemotherapy. Conservative management can be an option, but surgery must be optimal with negative margins. No benefit of axillary surgery has been shown but this treatment can lead to complications and impact quality of life of patients. Therefore, axillary node resection is not recommended for stage IV breast cancer. Finally, radiotherapy can be an alternative option of local therapy associated or no to surgery in stage IV breast cancer.

Increased expression of tumor necrosis factor-α is associated with advanced colorectal cancer stages

AIM: To detect the expression of tumor necrosis factor-α (TNF-α) in colorectal cancer (CRC) cells among Saudi patients, and correlate its expression with clinical stages of cancer.

METHODS: Archival tissue specimens were collected from 30 patients with CRC who had undergone surgical intervention at King Khalid University Hospital. Patient demographic information, including age and gender, tumor sites, and histological type of CRC, was recorded. To measure TNF-α mRNA expression in CRC, total RNA was extracted from tumor formalin-fixed, paraffin-embedded, and adjacent normal tissues. Reverse transcription and reverse transcription polymerase chain reaction were performed. Colorectal tissue microarrays were constructed to investigate the protein expression of TNF-α by immunohistochemistry.

RESULTS: The relative expression of TNF-α mRNA in colorectal cancer was significantly higher than that seen in adjacent normal colorectal tissue. High TNF-α gene expression was associated with Stage III and IV neoplasms when compared with earlier tumor stages (P = 0.004). Eighty-three percent of patients (25/30) showed strong TNF-α positive staining, while only 10% (n = 3/30) of patients showed weak staining, and 7% (n = 2/30) were negative. We showed the presence of elevated TNF-α gene expression in cancer cells, which strongly correlated with advanced stages of tumor.

CONCLUSION: High levels of TNF-α expression could be an independent diagnostic indicator of colorectal cancer, and targeting TNF-α might be a promising prognostic tool by assessment of the clinical stages of CRC.

In vivo and in vitro antitumor effects of platycodin d, a saponin purified from platycodi radix on the h520 lung cancer cell

Platycodin D is a major pharmacological constituent of Platycodi radix and has showed various pharmacological activities through oxidative stress defense mechanisms. Here, possible antitumor, anticachexia, and immunomodulatory activities of platycodin D were observed on the H520 tumor cell-bearing athymic nude mice after confirming the in vitro cytotoxicity. Platycodin D was orally administered at dose levels of 200, 100, and 50 mg/kg, once a day for 35 days from 15 days after implantation. The results were compared with gemcitabine 160 mg/kg intraperitoneally treated mice (7-day intervals). Platycodin D showed favorable cytotoxic effects on the H520 cells, and also dose-dependently decreased the tumor volumes and weights with increases of apoptotic cells (caspase-3 and PARP immunopositive cells), iNOS and TNF-α immunoreactivities, decreases of COX-2 immunoreactivities in tumor masses. Platycodin D also showed dose-dependent immunostimulatory and anticachexia effects. Gemcitabine showed favorable cytotoxity against H520 tumor cell and related in vivo antitumor effects but aggravated the cancer related cachexia and immunosuppress in H520 tumor cell-bearing athymic nude mice. Taken together, it is considered that oral treatment of platycodin D has potent antitumor activities on H520 cells through direct cytotoxic effects, increases of apoptosis in tumor cells, and immunostimulatory effects and can be control cancer related cachexia.

A role for T-lymphocytes in human breast cancer and in canine mammary tumors

Chronic inflammation in the tumor microenvironment has a prominent role in carcinogenesis and benefits the proliferation and survival of malignant cells, promoting angiogenesis and metastasis. Mammary tumors are frequently infiltrated by a heterogeneous population of immune cells where T-lymphocytes have a great importance. Interestingly, similar inflammatory cell infiltrates, cytokine and chemokine expression in humans and canine mammary tumors were recently described. However, in both species, despite all the scientific evidences that appoint for a significant role of T-lymphocytes, a definitive conclusion concerning the effectiveness of T-cell dependent immune mechanisms has not been achieved yet. In the present review, we describe similarities between human breast cancer and canine mammary tumors regarding tumor T-lymphocyte infiltration, such as relationship of TILs and mammary tumors malignancy, association of ratio CD4+/ CD8+ T-cells with low survival rates, promotion of tumor progression by Th2 cells actions, and association of great amounts of Treg cells with poor prognostic factors. This apparent parallelism together with the fact that dogs develop spontaneous tumors in the context of a natural immune system highlight the dog as a possible useful biological model for studies in human breast cancer immunology.

Rationale for the design of an oncology trial using a generic targeted therapy multi‑drug regimen for NSCLC patients without treatment options (Review)

Despite more than 70 years of research concerning medication for cancer treatment, the disease still remains one of the leading causes of mortality worldwide. Many cancer types lead to death within a period of months to years. The original class of chemotherapeutics is not selective for tumor cells and often has limited efficacy, while treated patients suffer from adverse side‑effects. To date, the concept of tumor‑specific targeted therapy drugs has not fulfilled its expectation to provide a key for a cure. Today, many oncology trials are designed using a combination of chemotherapeutics with targeted therapy drugs. However, these approaches have limited outcomes in most cancer indications. This perspective review provides a rationale to combine targeted therapy drugs for cancer treatment based on observations of evolutionary principles of tumor development and HIV infections. In both diseases, the mechanisms of immune evasion and drug resistance can be compared to some extent. However, only for HIV is a breakthrough treatment available, which is the highly active antiretroviral therapy (HAART). The principles of HAART and recent findings from cancer research were employed to construct a hypothetical model for cancer treatment with a multi‑drug regimen of targeted therapy drugs. As an example of this hypothesis, it is proposed to combine already marketed targeted therapy drugs against VEGFRs, EGFR, CXCR4 and COX2 in an oncology trial for non‑small cell lung cancer patients without further treatment options.

Gastrodin stimulates anticancer immune response and represses transplanted H22 hepatic ascitic tumor cell growth: Involvement of NF-κB signaling activation in CD4+ T cells

Gastrodia elata Blume (G. elata) is a famous restorative food in East Asia. It can be used as an auxiliary reagent in hepatocellular carcinoma (HCC) treatment. Previous studies unveiled that G. elata exhibited immunomodulatory activities. To explore the active ingredients contributing to its immunomodulatory activities, gastrodin, vanillin, and parishin B were purified from G. elata and their anti-HCC effects were assessed in vivo. Among these compounds, only gastrodin was capable of repressing transplanted H22 ascitic hepatic tumor cell growth in vivo with low toxicity. Further investigations were designed to explore the effects of gastrodin on the immune system of tumor-bearing mice and potential molecular mechanisms underlying these effects. Our data showed that gastrodin ameliorated tumor cell transplantation-induced activation of endogenous pro-apoptotic pathway in CD4+ T cells and abnormalities in serum cytokine profiles in host animals. These events enhanced cytotoxic activities of natural killer and CD8+ T cells against H22 hepatic cancer cells. Gastrodin administration specifically upregulated mRNA levels of several nuclear factor κB (NF-κB) responsive genes in CD4+ T cells but not in CD8+ T cells. Chromatin immunoprecipitation assay showed that gastrodin increased the association of NF-κB p65 subunit to the promoter regions of IL-2 and Bcl-2 encoding genes in CD4+ T cells. Our investigations demonstrated that gastrodin is the main active ingredient contributing to the anticancer immunomodulatory properties of G. elata. Promoting NF-κB-mediated gene transcription in CD4+ T cells is implicated in its immunomodulatory activity.

Myeloid-derived suppressor cells adhere to physiologic STAT3- vs STAT5-dependent hematopoietic programming, establishing diverse tumor-mediated mechanisms of immunologic escape

The receptor tyrosine kinase inhibitor, sunitinib, is astonishingly effective in its capacity to reduce MDSCs in peripheral tissues such as blood (human) and spleen (mouse), restoring responsiveness of bystander T lymphocytes to TcR stimulation. Sunitinib blocks proliferation of undifferentiated MDSCs and decreases survival of more differentiated neutrophilic MDSC (n-MDSC) progeny. Ironically, sunitinib's profound effects are observed even in a total absence of detectable anti-tumor therapeutic response. This is best explained by the presence of disparate MDSC-conditioning stimuli within individual body compartments, allowing sensitivity and resistance to sunitinib to coexist within the same mouse or patient. The presence or absence of GM-CSF is likely the major determinant in each compartment, given that GM-CSF's capacity to preempt STAT3-dependent with dominant STAT5-dependent hematopoietic programming confers sunitinib resistance and redirects differentiation from the n-MDSC lineage to the more versatile monocytoid (m-MDSC) lineage. The clinical sunitinib experience underscores that strategies for MDSC and Treg depletions must be mindful of disparities among body compartments to avoid sanctuary effects. Ironically, m-MDSCs manifesting resistance to sunitinib also have the greatest potential to differentiate into tumoricidal accessory cells, by virtue of their capacity to respond to T cell-secreted IFN-γ or to TLR agonists with nitric oxide and peroxynitrate production.

Tumor necrosis factor-α is associated with positive lymph node status in patients with recurrence of colorectal cancer-indications for anti-TNF-α agents in cancer treatment

INTRODUCTION

The progressive growth of malignancies is accompanied by a decline in the immune response through mechanisms which are poorly understood. Apoptosis and induction of inflammation by tumor released cytokines as tumor escape mechanisms have been proposed to play an important role in colorectal carcinogenesis.

METHODS

Expression of Tumor necrosis factor-alpha (TNF-α) was analyzed in colorectal cancer specimen and the cancer cell line HT-29 by immunohistochemistry and RT-PCR. TNF-α expression on protein and mRNA level were correlated with clinical characteristics and impact on survival. TNFR-1 was co-labelled with TNF-α and CD8+ cytotoxic T cells in immunofluorescence double staining experiments.

RESULTS

94% (n = 98/104) of the patients with CRC expressed TNF-α. High TNF-α expression was significantly associated with positive lymph node stage and recurrence of the tumor. Multivariate analysis revealed high TNF-α expression as an independent prognostic factor. Immunohistochemistry was correlated with RT-PCR results (т = 0.794). Immunofluorescence double staining experiments revealed increased TNFR-1 expression by CD8+ cells.

CONCLUSIONS

TNF-α expression by tumor cells may be an efficient immunological escape mechanism by inflammation-enhanced metastases and probably by induction of apoptosis in tumor-infiltrating CD8+ immune cells resulting in a down regulation of the tumoral immune response. Our data support the role of tumor-derived TNF-α expression as an important promoter of tumoral immune escape mechanisms and malignant progression, and suggest that analysis on either protein (immunohistochemistry) or RNA level (RT-PCR) can be used effectively in this respect. Targeting TNF-α may be a promising option, especially in cases with high TNF-α expression and positive lymph node metastases.

Serum neopterin levels in female dogs with malignant mammary tumours

In this study, we have determined serum neopterin levels in female dogs with primary malignant mammary tumours. The study involved 50 female dogs which had a malignant mammary tumours removed surgically (32 animals with carcinoma, 12 animals with sarcoma and 6 animals with carcinosarcoma) and 10 clinically healthy female dogs. Serum neopterin levels were determined using a commercial ELISA kit. The mean neopterin levels were lower in the malignant tumour groups than in healthy animals but differences were statistically significant only in carcinoma and sarcoma groups. The decrease of neopterin levels in animals with malignant mammary tumours may suggest their decreased cellular immunity. Moreover, it might indicate that decreased activity of cellular mechanisms of the anti-neoplastic response is one of the factors associated with the development and course of malignant mammary tumours in female dogs; however, further studies are necessary.

Nifetepimine, a dihydropyrimidone, ensures CD4+ T cell survival in a tumor microenvironment by maneuvering sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA)

Multiple mechanisms have been proposed by which tumors induce T cell apoptosis to circumvent tumor immune-surveillance. Although sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) have long been known to regulate intracellular Ca(2+) homeostasis, few studies have examined the role of SERCA in processes of T lymphocyte survival and activation. In this context it remains largely unexplored as to how tumors jeopardize SERCA function to disable T cell-mediated anti-tumor immunity. Here, we show that human CD4(+) T cells in the presence of tumor conditions manifested an up-regulation of SERCA3 expression that resulted in development of endoplasmic reticulum stress leading to CD4(+) T cell apoptosis. Prostaglandin E(2) produced by the tumor cell plays a critical role in up-regulating SERCA3 by enhancing the binding of its transcription factor Sp1. Gene manipulation and pharmacological approaches further established that an increase in SERCA expression also resulted in subsequent inhibition of PKCα and -θ and retention of NFκB in the cytosol; however, down-modulation of SERCA3 expression by a dihydropyrimidone derivative, ethyl-4-(3-nitro)-phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5 carboxylate (nifetepimine), protected the CD4(+) T cells from tumor-induced apoptosis. In fact, nifetepimine-mediated restoration of PKC activity resulted in nuclear translocation of p65NFκB, thereby ensuring its survival. Studies further undertaken in a tumor-bearing mice model revalidated the immunoprotective role of nifetepimine. Our present study thus strongly suggests that imbalance in cellular calcium homeostasis is an important factor leading to CD4(+) T cell death during cancer and holds promise that nifetepimine may have the potential to be used as an immunorestoring agent in cancer bearers.

CD70 expression patterns in renal cell carcinoma

CD70 is up-regulated in several malignancies, where it induces cytotoxic effects on B and T lymphocytes, leading to immune escape. Novel therapeutic agents targeting CD70 have entered clinical trials. We characterized expression of CD70 protein in renal cell carcinoma specimens of various histologic subtypes and assessed their prognostic value and association with clinical/pathologic variables. We used tissue microarrays containing 330 cases using a novel fluorescent immunohistochemistry-based method of Automated Quantitative Analysis of in situ protein expression. The mean expression of CD70 was almost twice as high in tumors relative to normal tissue (P < .0001). When broken into subsets, CD70 was higher in sarcomatoid and clear cell tumors (P < .0001) and was variably elevated in oncocytomas and some papillary tumors. No association was found between CD70 expression and stage or grade. High CD70 expression was associated with decreased survival on univariate analysis in the clear cell subset of renal cell carcinoma; however, it did not retain significance on multivariate analysis. Given the elevated expression of CD70 in clear cell, sarcomatoid, and some papillary tumors, our findings suggest that CD70 might be a good drug target in renal cell carcinoma. Additional studies are warranted to assess the association between expression of CD70 and response to therapy with CD70-targeting drugs in renal cell carcinoma.

Fas expression in renal cell carcinoma accurately predicts patient survival after radical nephrectomy

OBJECTIVES

To investigate Fas, Fas ligand (FasL) and Bcl-2 expression, which are considered to be important apoptotic regulatory factors in renal cell carcinomas (RCCs).

PATIENTS AND METHODS

mRNA quantification and immunohistochemistry allowed for the determination of the expression of these three factors in surgically resected tumors from 82 patients with RCC. The correlation of protein and gene expression with more than 10 years of survival data following nephrectomy (along with clinical and pathologic parameters) was analyzed using uni- and multivariate statistical models.

RESULTS

A significantly poorer outcome was observed in patients with tumors expressing high levels of Fas mRNA in the multivariate analysis (p = 0.0002). In addition, patient survival was significantly worse in FasL mRNA-positive tumor cases when compared with FasL mRNA-negative cases (p = 0.0345). Ten cases relapsed more than 5 years after nephrectomy. Among them, the tumors of 8 cases (80%) did not express FasL mRNA. Analysis of Bcl-2 did not show statistical significance of Bcl-2 expression as a prognostic indicator.

CONCLUSIONS

The data suggest that pronounced Fas expression is a surrogate biomarker of active cancer cell proliferation. Given the FasL tumor counterattack theory, FasL overexpression in RCC may be one of the host immune deficiencies, consequently leading to poor prognosis.

The significant immunological characteristics of peripheral blood neutrophil-to-lymphocyte ratio and Fas ligand expression incidence in nephrectomized tumor in late recurrence from renal cell carcinoma

OBJECTIVE

In order to characterize the significance of immune system function in patients with advanced renal cell carcinoma (RCC), we investigated the interactive relationships among the following parameters: metastatic characteristics, expression of Fas ligand (FasL) in nephrectomized specimens, immunological parameters, and patient's prognosis.

MATERIALS AND METHODS

Thirty-five patients with advanced RCC were stratified into 3 groups according to the characteristics of metastasis timing, at first presentation (mFP), within 5 years of nephrectomy (early-recurrence), after 5 years (late-recurrence). Immunological parameters [hemoglobin, lymphocyte count, neutrophil/lymphocyte ratio (NLR), serum albumin, Eastern Cooperative Oncology Group (ECOG) performance status (PS), and Charlson Comorbidity Index], FasL expression in RCC, and patient prognosis from occurrence of metastasis were compared among the groups. Thirty-five patients were also stratified into 2 groups according to FasL positivity and individual parameters. Patient's prognosis and the remaining immunological parameters were compared between groups.

RESULTS

The NLRs of the late-recurrence group were significantly lower than those of the mFP (P = 0.0004) and early-recurrence (P = 0.013) groups. The FasL mRNA positivity of the late-recurrence group was significantly lower than those of the mFP (P = 0.001) and early-recurrence (P = 0.0277) groups. The prognosis of the late-recurrence group was significantly better than that of the early-recurrence group (P = 0.0255). NLRs were significantly lower in the FasL-negative group than in the -positive group (P = 0.0182). The cause-specific survival rates of the ECOG PS 0 group were significantly higher than that of the ECOG PS > 0 group (P < 0.0001).

CONCLUSIONS

Our results suggest the associations of the prognosis in advanced RCC with peripheral blood NLR and FasL expression in nephrectomized tumor. The characteristics of lower values of NLR and FasL expression positivity in late-recurrence compared with other metastatic timings suggest strong host immune activity, and may imply relatively long survival. On the other hand, elucidation of the patient's general condition obtained not only by chemical data but also by ECOG PS is crucial in the management of patients with advanced RCC.

CTL recognition of a novel HLA-A*0201-binding peptide derived from glioblastoma multiforme tumor cells

Genetic instability of tumor cells can result in translation of proteins that are out of frame, resulting in expression of neopeptides. These neopeptides are not self-proteins and therefore should be immunogenic. By eluting peptides from human glioblastoma multiforme (GBM) tumor cell surfaces and subjecting them to tandem mass spectrometry, we identified a novel peptide (KLWGLTPKVTPS) corresponding to a frameshift in the 3' beta-hydroxysteroid dehydrogenase type 7 (HSD3B7) gene. HLA-binding algorithms predicted that a 9-amino acid sequence embedded in this peptide would bind to HLA-A*0201. We confirmed this prediction using an HLA-A*0201 refolding assay followed by live cell relative affinity assays, but also showed that the 12-mer binds to HLA-A*0201. Based on the 9-mer sequence, optimized peptide ligands (OPL) were designed and tested for their affinities to HLA-A*0201 and their abilities to elicit anti-peptide and CTL capable of killing GBM in vitro. Wild-type peptides as well as OPL induced anti-peptide CTL as measured by IFN-γ ELISPOTS. These CTL also killed GBM tumor cells in chromium-51 release assays. This study reports a new CTL target in GBM and further substantiates the concept that rational design and testing of multiple peptides for the same T-cell epitope elicits a broader response among different individuals than single peptide immunization.

Protective effects of diosmetin extracted from Galium verum L. on the thymus of U14-bearing mice

Diosmetin (DGVL) extracted from the traditional Chinese herb Galium verum L. has been found to have anticancer activity. In this study, the effects of DGVL on the thymus of U14-bearing mice were investigated. Using flow cytometry, peripheral blood lymphocytes were characterized based on the expression of surface markers for T helper cells (CD4+) and T suppressor cells (CD8+). Serum levels of tumor necrosis factor α (TNF-α), interleukin-2 (IL-2), IL-10, and transforming growth factor β1 (TGF-β1) and a cell proliferation assay were determined with an enzyme-linked immunosorbent assay. The expression of Fas and Fas ligand (FasL) on the thymus was determined by Western blotting. Our results showed that DGVL inhibited tumor growth and significantly increased the thymus weight compared with the control. Also, DGVL elevated serum levels of IL-2 and significantly reduced levels of TNF-α, TGF-β1, and IL-10 in a dose-dependent manner. Histological study and terminal dUTP nick end labeling staining results showed that DGVL protected thymus tissue against the onslaught of tumor growth by inhibiting thymus lymphocyte apoptosis. The cell proliferation assay revealed that DGVL might promote more thymus lymphocytes towards proliferation. Furthermore, the ratio of CD4+/CD8+ T lymphocytes was significantly increased from 0.69 to 2.29 by treatment with DGVL. Immunoblotting analyses revealed that the expression of Fas and FasL on the thymus was lower in mice in the DGVL treatment group than in the control mice. In conclusion, DGVL can inhibit tumor growth and protect tumor-induced apoptosis of the thymus, and the mechanism is closely associated with reduced cell death in the thymus and a Fas–FasL-dependent pathway.

Cancer patients treated with sunitinib or sorafenib have sufficient antibody and cellular immune responses to warrant influenza vaccination

PURPOSE

The tyrosine kinase inhibitors sorafenib and sunitinib have efficacy in several types of cancer. Recent studies indicate that these agents affect the immune system. The way it affects the immune response to influenza vaccination is unknown. The aim of this study was to elucidate the specific immune response to seasonal flu vaccination in cancer patients treated with sunitinib or sorafenib.

PATIENTS AND METHODS

Sunitinib- or sorafenib-treated cancer patients were vaccinated against seasonal influenza with an inactivated vaccine. Healthy controls and patients with metastatic renal cell cancer (mRCC) without systemic treatment (nontreated mRCC controls) were included for comparison. Antibody responses were measured at baseline, day 8, and day 22 by a standard hemagglutination inhibition assay and cellular T-cell responses at baseline and day 8 by proliferation assay and secretion of cytokines.

RESULTS

Forty subjects were enrolled: 16 patients treated with sunitinib, 6 patients with sorafenib, 7 nontreated mRCC controls, and 11 healthy controls. All patients treated with sunitinib and sorafenib developed seroprotection rates comparable with controls. Functional T-cell reactivity was observed in all groups, except for patients treated with sorafenib who showed a decreased proliferation rate and IFN-γ/IL-2 production and increased IL-10 compared with healthy controls.

CONCLUSION

We conclude that influenza vaccination should be recommended to cancer patients treated with sunitinib or sorafenib.

Ultrasound-based combination therapy: potential in urologic cancer

Immune-sensitive urologic malignancies include prostate, kidney and bladder cancers. To date, most immunotherapeutic treatments have been applied to advanced metastatic disease. Limited efficacy in this setting is likely due to an excessive disease burden, which overwhelms the capacity of the immune system. Immunotherapy has not been widely utilized in a low-disease-burden state - a setting in which the immune system may be best suited to effectively mount a clinically meaningful response. The emergence of high-intensity focused ultrasound, and more recently, low-intensity focused ultrasound technologies, have demonstrated not only immune-stimulatory effects but also an interesting capacity to alter tissue architecture and cell membrane properties, which may be exploited to increase tumoral uptake of drugs and vaccines. In this article, we review the literature supporting the novel use of ultrasound combination therapy with adjunctive agents in the treatment of urologic malignancy.

Early expression of stem cell-associated genes within the CD8 compartment after treatment with a tumor vaccine

Using a mouse neuroblastoma cell line, we have demonstrated that vaccination of tumor-free mice with a cell-based vaccine leads to productive immunity and resistance to tumor challenge, while vaccination of tumor-bearing mice does not. The T cell immunity induced by this vaccine, as measured by in vitro assays, is amplified by the depletion of Treg. Our goal is to understand this barrier to the development of protective cellular immunity. mRNA microarray analyses of CD8(+) T cells from naïve or tumor-bearing mice undergoing vaccination were carried out with or without administering anti-CD25 antibody. Gene-expression pathway analysis revealed the presence of CD8(+) T cells expressing stem cell-associated genes early after induction of productive anti-tumor immunity in tumor-free mice, prior to any phenotypic changes, but not in tumor-bearing mice. These data demonstrate that early after the induction of productive immune response, cells within the CD8(+) T cell compartment adopt a stem cell-related genetic phenotype that correlates with increased anti-tumor function.

CCL2 blockade augments cancer immunotherapy

Altering the immunosuppressive microenvironment that exists within a tumor will likely be necessary for cancer vaccines to trigger an effective antitumor response. Monocyte chemoattractant proteins (such as CCL2) are produced by many tumors and have both direct and indirect immunoinhibitory effects. We hypothesized that CCL2 blockade would reduce immunosuppression and augment vaccine immunotherapy. Anti-murine CCL2/CCL12 monoclonal antibodies were administered in three immunotherapy models: one aimed at the human papillomavirus E7 antigen expressed by a non-small cell lung cancer (NSCLC) line, one targeted to mesothelin expressed by a mesothelioma cell line, and one using an adenovirus-expressing IFN-alpha to treat a nonimmunogenic NSCLC line. We evaluated the effect of the combination treatment on tumor growth and assessed the mechanism of these changes by evaluating cytotoxic T cells, immunosuppressive cells, and the tumor microenvironment. Administration of anti-CCL2/CCL12 antibodies along with the vaccines markedly augmented efficacy with enhanced reduction in tumor volume and cures of approximately half of the tumors. The combined treatment generated more total intratumoral CD8+ T cells that were more activated and more antitumor antigen-specific, as measured by tetramer evaluation. Another important potential mechanism was reduction in intratumoral T regulatory cells. CCL2 seems to be a key proximal cytokine mediating immunosuppression in tumors. Its blockade augments CD8+ T-cell immune response to tumors elicited by vaccines via multifactorial mechanisms. These observations suggest that combining CCL2 neutralization with vaccines should be considered in future immunotherapy trials.

Elevated levels of select gangliosides in T cells from renal cell carcinoma patients is associated with T cell dysfunction

Increased expression of gangliosides by different tumor types including renal cell carcinoma (RCC) is thought to contribute to the immune suppression observed in cancer patients. In this study, we report an increase in apoptotic T cells from RCC patients compared with T cells from normal donors that coincided with the detection of T cells staining positive for GM2 and that the apoptosis was predominantly observed in the GM2(+) but not the GM2(-) T cell population. Ganglioside shedding from tumor rather than endogenous production accounts for GM2(+) T cells since there was no detectable level of mRNA for GM2 synthase in RCC patient T cells and in T cells from normal healthy donors after incubation with either purified GM2 or supernatant from RCC cell lines despite their staining positive for GM2. Moreover, reactive oxygen species as well as activated caspase 3, 8, and 9 were predominantly elevated in GM2(+) but not GM2(-) T cells. Similarly, increased staining for GD2 and GD3 but not GD1a was detected with patient T cells with elevated levels of apoptosis in the GD2(+) and GD3(+) cells. These findings suggest that GM2, GD2, and GD3 play a significant role in immune dysfunction observed in RCC patient T cells.

Tumor-shed PGE(2) impairs IL2Rgammac-signaling to inhibit CD4 T cell survival: regulation by theaflavins

Background

Many tumors are associated with decreased cellular immunity and elevated levels of prostaglandin E2 (PGE2), a known inhibitor of CD4+ T cell activation and inducer of type-2 cytokine bias. However, the role of this immunomodulator in the survival of T helper cells remained unclear. Since CD4+ T cells play critical roles in cell-mediated immunity, detail knowledge of the effect tumor-derived PGE2 might have on CD4+ T cell survival and the underlying mechanism may, therefore, help to overcome the overall immune deviation in cancer.

Methodology/Principal Findings

By culturing purified human peripheral CD4+ T cells or Jurkat cells with spent media of theaflavin- or celecoxib-pre-treated MCF-7 cells, we show that tumor-shed PGE2 severely impairs interleukin 2 receptor γc (IL2Rγc)-mediated survival signaling in CD4+ T cells. Indeed, tumor-shed PGE2 down-regulates IL2Rγc expression, reduces phosphorylation as well as activation of Janus kinase 3 (Jak-3)/signal transducer and activator of transcription 5 (Stat-5) and decreases Bcl-2/Bax ratio thereby leading to activation of intrinsic apoptotic pathway. Constitutively active Stat-5A (Stat-5A1*6) over-expression efficiently elevates Bcl-2 levels in CD4+ T cells and protects them from tumor-induced death while dominant-negative Stat-5A over-expression fails to do so, indicating the importance of Stat-5A-signaling in CD4+ T cell survival. Further support towards the involvement of PGE2 comes from the results that (a) purified synthetic PGE2 induces CD4+ T cell apoptosis, and (b) when knocked out by small interfering RNA, cyclooxygenase-2 (Cox-2)-defective tumor cells fail to initiate death. Interestingly, the entire phenomena could be reverted back by theaflavins that restore cytokine-dependent IL2Rγc/Jak-3/Stat-5A signaling in CD4+ T cells thereby protecting them from tumor-shed PGE2-induced apoptosis.

Conclusions/Significance

These data strongly suggest that tumor-shed PGE2 is an important factor leading to CD4+ T cell apoptosis during cancer and raise the possibility that theaflavins may have the potential as an effective immunorestorer in cancer-bearer.

Chemoradioimmunotherapy in locally advanced pancreatic and biliary tree adenocarcinoma: a multicenter phase II study

OBJECTIVES

The antitumor activity and toxicity of a multi-step treatment were evaluated in patients with locally advanced, inoperable, or incompletely resected pancreatic (Pa) and biliary tree (Bt) adenocarcinomas (ADKs).

METHODS

Fifty-four patients, 63% with Pa and 37% with Bt ADK, received 3 courses of cisplatin-gemcitabine induction chemotherapy. Progression-free (PF) patients were given consolidation radiotherapy with concurrent capecitabine. PF patients had, as maintenance immunotherapy (MI), interleukin 2 (1.8x10 IU) and 13-cis-retinoic acid (0.5 mg/kg) [DOSAGE ERROR CORRECTED].

RESULTS

Thirty-eight patients, 27 with Pa and 11 with Bt ADKs, PF after cisplatin/gemcitabine, were treated with consolidation radiotherapy with concurrent capecitabine. Fourteen PF patients, 7 with Pa and 7 with Bt ADK, received MI. Median PF and overall survivals (OS) for all 54 patients were 6.8 and 12.1 months, respectively. Patients treated with MI had a median PF survival of 16.2 months, whereas median OS had not been reached yet, after a median follow-up of 27.5 months.

TOXICITY

Grades 3 and 4 hematological and gastrointestinal in 30% and 37% of patients, respectively; grades 1 and 2 autoimmune reactions in 28% of patients.

CONCLUSIONS

These results support the efficacy and safety of a multi-step sequential treatment in patients with locally advanced, inoperable or incompletely resected Pa and Bt ADKs.

Respiratory Homeostasis and Exploitation of the Immune System for Lung Cancer Vaccines

Lung cancer is the leading cause of all cancer deaths in the US. The international scientific and clinical community has made significant advances toward understanding specific molecular mechanisms underlying lung carcinogenesis; however, despite these insights and advances in surgery and chemoradiotherapy, the prognosis for non-small-cell lung cancer (NSCLC) remains poor. Nonetheless, significant effort is being focused on advancing translational research evaluating the efficacy of novel targeted therapeutic strategies for lung cancer. Illustrative examples of this include antagonists of the epidermal growth factor receptor (EGFR), tyrosine kinase inhibitors (TKIs) such as gefitinib and erlotinib, and a diverse assortment of anti-angiogenic compounds targeting growth factors and/or their receptors that regulate tumor-associated angiogenic programs. In addition, with the increased awareness of the significant role chronically activated leukocytes play as potentiators of solid-tumor development, the role of innate and adaptive immune cells as regulators of lung carcinogenesis is being examined. While some of these studies are examining how novel therapeutic strategies may enhance the efficacy of lung cancer vaccines, others are evaluating the intrinsic characteristics of the immune response to lung cancer in order to identify rate-limiting molecular and/or cellular programs to target with novel anticancer therapeutics. In this article, we explore important aspects of the immune system and its role in regulating normal respiratory homeostasis compared with the immune response accompanying development of lung cancer. These hallmarks are then discussed in the context of recent efforts to develop lung cancer vaccines, where we have highlighted important concepts that must be taken into consideration for future development of novel therapeutic strategies and clinical trials assessing their efficacy.

Sunitinib reverses type-1 immune suppression and decreases T-regulatory cells in renal cell carcinoma patients

PURPOSE

Immune dysfunction is well documented in renal cell carcinoma (RCC) patients and likely contributes to tumor evasion. This dysfunction includes a shift from a type-1 to a type-2 T-cell cytokine response and enhanced T-regulatory (Treg) cell expression. Given the antitumor activity of select tyrosine kinase inhibitors such as sunitinib in metastatic RCC (mRCC) patients, it is relevant to assess their effect on the immune system.

EXPERIMENTAL DESIGN

Type-1 (IFNgamma) and type-2 (interleukin-4) responses were assessed in T cells at baseline and day 28 of treatment with sunitinib (50 mg/d) by measuring intracellular cytokines after in vitro stimulation with anti-CD3/anti-CD28 antibodies.

RESULTS

After one cycle of treatment, there was a significant increase in the percentage of IFNgamma-producing T cells (CD3(+), P < 0.001; CD3(+)CD4(+), P = 0.001), a reduction in interleukin-4 production (CD3(+) cells, P = 0.05), and a diminished type-2 bias (P = 0.005). The increase in type-1 response may be partly related to modulation of Treg cells. The increased percentage of Treg cells noted in mRCC patients over healthy donors (P = 0.001) was reduced after treatment, although not reaching statistical significance. There was, however, an inverse correlation between the increase in type-1 response after two cycles of treatment and a decrease in the percentage of Treg cells (r = -0.64, P = 0.01). In vitro studies suggest that the effects of sunitinib on Treg cells are indirect.

CONCLUSIONS

The demonstration that sunitinib improved type-1 T-cell cytokine response in mRCC patients while reducing Treg function provides a basis for the rational combination of sunitinib and immunotherapy in mRCC.

Cytokines and their relationship to the symptoms and outcome of cancer

Tumours contain immune cells and a network of pro- and anti-inflammatory cytokines, which collaborate in the development and progression of cancer. Cytokine profiles might prove to be prognostic. The systemic effects of pro-inflammatory cytokines are associated with fatigue, depression and cognitive impairment, and can affect quality of life before, during and after treatment. In people with advanced cancer, pro-inflammatory cytokines are additionally associated with anorexia and cachexia, pain, toxicity of treatment and resistance to treatment. However, physical activity might modify cytokine levels and decrease fatigue in patients with cancer, and might also improve their prognosis.

Tumors skew endothelial cells to disrupt NK cell, T-cell and macrophage functions

INTRODUCTION

Patients and mice with solid tumors, such as Lewis lung carcinoma (LLC), have defects in functions of immune effector cells. Endothelial cells, a component of the tumor vasculature, are potential regulators of immune cell functions. Therefore, these studies examined the impact of exposure to LLC tumor on the ability of endothelial cells to modulate immune cell functions.

MATERIALS AND METHODS

Endothelial cells were pre-treated with LLC tumor-conditioned medium (Endo(T-sup)) for 24 h. Control endothelial cells that were exposed to medium (Endo(Media)) epithelial cell-conditioned medium or (Endo(Epi-sup)). After the initial 24 h incubation, endothelial cells were washed and fresh media was added. Cells were allowed to incubate for an additional 24 h. Supernatants from Endo(Media), Endo(Epi-sup) or Endo(T-sup) were collected and assayed for immune modulatory products and for immune modulatory activity.

RESULTS

Supernatant from Endo(T-sup) contained increased levels of PGE2, IL-6 and VEGF as compared to Endo(Media) and Endo(Epi-sup) controls. NK cell activity, as measured by TNF-alpha and IFN-gamma secretion, was increased following exposure to media conditioned by Endo(Media) and Endo(Epi-sup) Exposure of NK cells to supernatants of Endo(T-sup), also increases TNF-alpha and IFN-gamma secretion, but to a lesser extent than by Endo(Media) and Endo(Epi-sup). Examination of macrophage functions demonstrated that supernatant from Endo(T-sup) decreased microbead phagocytosis and increased production of the immune suppressive mediators, IL-10 and PGE2. Lastly, T-cell responses to stimulation with anti-CD3 in the presence of supernatants from Endo(T-sup) were examined. IFN-gamma production by CD8+ T-cells was reduced after exposure to Endo(T-sup)-conditioned medium, as compared to cells treatments with medium or control conditioned medium. Production of IFN-gamma by CD4+ T-cells exposed to Endo(T-sup) was not altered.

CONCLUSIONS

Taken together, these studies demonstrate that tumors skew endothelial cells to disrupt NK cell, T-cell and macrophages functions, and represents a novel mechanism of tumor-induced immune suppression.

Fas-mediated T cell deletion potentiates tumor antigen-specific tolerance in a mouse model of prostate cancer

A pivotal obstacle to cancer immunotherapy is peripheral T cell tolerance to tumor-associated antigens (TAAs). Tolerance induction among mature T cells in the periphery operates through a variety of mechanisms, including anergy and apoptosis. Although Fas-FasL-mediated apoptosis is a well-defined tolerance inducing mechanism, direct evidence of its interference with TAA-specific immunity in vivo is still lacking. In this report, we used the TRAMP mouse, which expresses SV40 large T antigen (Tag) preferentially in the prostate and develops prostate tumors, as a model system to address the role of Fas-mediated apoptosis in regulating peripheral T cell tolerance. Using RT-PCR and tetramer staining to quantify TAA-specific TCR-expressing cytolytic T lymphocytes (CTLs), we have shown the presence of TAA-specific CTLs at higher levels in TRAMP mice than in syngeneic C57Bl/6 mice. Tag-specific immunization led to the expansion of Tag-specific CTLs in C57Bl/6 mice, and to their elimination in TRAMP mice. Interestingly, in TRAMP mice with deficient Fas (Hybrid TRAMP-lpr/lpr), Tag-specific CTL elimination in response to Tag immunization did not take place. The results of cytolytic-function assays were consistent with induction and elimination patterns of TAA-specific CTLs and those of RT-PCR and tetramer staining. In conclusion, our data show that Fas-mediated TAA-specific CTL apoptosis contributes to T cell tolerance and suggest that such tolerance could be potentiated following TAA-specific immunization.

Renal cell carcinoma tumors induce T cell apoptosis through receptor-dependent and receptor-independent pathways

Tumors can promote their own progressive growth by inducing T cell apoptosis. Though previous studies suggested that tumor-mediated T cell killing is receptor dependent, we recently showed that tumor gangliosides also participate, a notion consistent with reports indicating that, in some cell types, gangliosides can activate the intrinsic apoptotic pathway by stimulating reactive oxygen species production, cytochrome c release, and caspase-9 activation. In this study, we used normal peripheral blood T cells, as well as caspase-8-, caspase-9-, and Fas-associated death domain protein-deficient Jurkat cells, to assess whether the death ligands and gangliosides overexpressed by the renal cell carcinoma (RCC) cell line SK-RC-45 can independently stimulate T cell apoptosis as a mechanism of immune escape. Anti-FasL Abs and the glycosylceramide synthase inhibitor 1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol (PPPP) each partially inhibited the ability of SK-RC-45 to kill cocultured activated T cells; together, as purified molecules, RCC gangliosides and rFasL induced a more extensive mitochondrial permeability transition and greater levels of apoptosis than either agent alone, equivalent to that induced by the FasL- and ganglioside-expressing RCC line itself. rFasL-mediated apoptosis was completely inhibited in caspase-8- and Fas-associated death domain protein-negative Jurkat cells, though apoptosis induced by purified gangliosides remained intact, findings that correlate with the observed partial inhibition of SK-RC-45-induced apoptosis in the Jurkat lines with defective death receptor signaling. Western blot analysis performed on lysates made from wild-type and mutant Jurkat cells cocultured with SK-RC-45 revealed caspase activation patterns and other biochemical correlates which additionally supported the concept that tumor-associated gangliosides and FasL independently activate the caspase cascade in T cells through the intrinsic and extrinsic pathways, respectively.

Inflammation and breast cancer. Balancing immune response: crosstalk between adaptive and innate immune cells during breast cancer progression

Recent insights into the molecular and cellular mechanisms underlying cancer development have revealed that immune cells functionally regulate epithelial cancer development and progression. Moreover, accumulated clinical and experimental data indicate that the outcome of an immune response toward an evolving breast neoplasm is largely determined by the type of immune response elicited. Acute tumor-directed immune responses involving cytolytic T lymphocytes appear to protect against tumor development, whereas immune responses involving chronic activation of humoral immunity, infiltration by Th2 cells, and protumor-polarized innate inflammatory cells result in the promotion of tumor development and disease progression. Herein we review this body of literature and summarize important new findings revealing the paradoxical role of innate and adaptive leukocytes as regulators of breast carcinogenesis.

Changes in circulating immunosuppressive cytokine levels of cancer patients after high intensity focused ultrasound treatment

Immunosuppression in a patient with malignant tumor is a major obstacle in cancer treatment. In this study, we investigated changes in the circulating level of all measured immunosuppressive cytokines in patients with malignancy before and after high intensity focused ultrasound (HIFU) treatment. Fifteen patients with solid malignancy were enrolled in this study and an enzyme-linked immunoabsorbent assay (ELISA) method was used to measure serum level of vascular endothelial growth factor (VEGF), transforming growth factor-beta1 (TGF-beta1), transforming growth factor-beta2 (TGF-beta2), interleukin 6 (IL-6) and interleukin 10 (IL-10), respectively before and 1 wk after HIFU treatment. Among them, seven patients had distant metastasis and the remaining eight had no metastasis. All patients received one-session HIFU treatment for primary cancer, including complete ablation in eight patients without metastasis, and partial ablation in seven patients with metastases. The results showed that serum immunosuppressive cytokine levels decreased after HIFU treatment, and there were significant decreases of VEGF, TGF-beta1, and TGF-beta2 before and after HIFU treatment. Compared with the values in the metastatic patients, serum levels of immunosuppressive cytokines were significantly lower in the nonmetastatic patients after HIFU treatment. It is concluded that HIFU can decrease tumor-secreted immunosuppressive cytokine production in addition to its direct tumor destruction. This change may lessen tumor-induced immunosuppression and renew antitumor immunity after HIFU in cancer patients.

Immune cells as anti-cancer therapeutic targets and tools

Chronic inflammation is a contributing factor to overall cancer risk as well as cancer promotion and progression; however, pathways regulating onset of cancer-promoting inflammatory responses are still poorly understood. Clinical data suggest that deficient anti-tumor cell-mediated immunity, in combination with enhanced pro-tumor humoral and/or innate immunity (inflammation), are significant factors influencing malignant outcome. Here, we discuss therapeutic implications from clinical data and experimental studies using de novo immune-competent mouse models of cancer development that together are revealing molecular and cellular mechanisms underlying interactions between immune cells and evolving neoplastic cells that regulate cancer outcome. Understanding the functionally significant links between adaptive and innate immunity that regulate cancer development will open new therapeutic opportunities to manipulate aspects of immunobiology and minimize lethal effects of cancer development.

TNF-alpha induction of GM2 expression on renal cell carcinomas promotes T cell dysfunction

Previous studies from our laboratory demonstrated the role of tumor-derived gangliosides as important mediators of T cell apoptosis, and hence, as one mechanism by which tumors evade immune destruction. In this study, we report that TNF-alpha secreted by infiltrating inflammatory cells and/or genetically modified tumors augments tumor-associated GM2 levels, which leads to T cell death and immune dysfunction. The conversion of weakly apoptogenic renal cell carcinoma (RCC) clones to lines that can induce T cell death requires 3-5 days of TNF-alpha pretreatment, a time frame paralleling that needed for TNF-alpha to stimulate GM2 accumulation by SK-RC-45, SK-RC-54, and SK-RC-13. RCC tumor cell lines permanently transfected with the TNF-alpha transgene are similarly toxic for T lymphocytes, which correlates with their constitutively elevated levels of GM2. TNF-alpha increases GM2 ganglioside expression by enhancing the mRNA levels encoding its synthetic enzyme, GM2 synthase, as demonstrated by both RT-PCR and Southern analysis. The contribution of GM2 gangliosides to tumor-induced T cell death was supported by the finding that anti-GM2 Abs significantly blocked T cell apoptosis mediated by TNF-alpha-treated tumor cells, and by the observation that small interfering RNA directed against TNF-alpha abrogated GM2 synthase expression by TNF-transfected SK-RC-45, diminished its GM2 accumulation, and inhibited its apoptogenicity for T lymphocytes. Our results indicate that TNF-alpha signaling promotes RCC-induced killing of T cells by stimulating the acquisition of a distinct ganglioside assembly in RCC tumor cells.

Cysteine cathepsins: regulators of antitumour immune response

Cysteine cathepsins are lysosomal cysteine proteases that are involved in a number of important biological processes, including intracellular protein turnover, propeptide and hormone processing, apoptosis, bone remodelling and reproduction. In cancer, the cathepsins have been linked to extracellular matrix remodelling and to the promotion of tumour cell motility, invasion, angiogenesis and metastasis, resulting in poor outcome of cancer patients; however, cysteine cathepsins are also involved at different levels of the innate and adaptive immune responses. Their best known role in this aspect is their contribution to major histocompatibility complex class II antigen presentation, the processing of progranzymes into proteolytically active forms, cytotoxic lymphocyte self-protection, cytokine and growth factor degradation and, finally, the induction of cytokine expression and modulation of integrin function. This review is focused on the role of cysteine cathepsins in the antitumour immune response and the evaluation of their pro- and anticancer behaviours during the regulation of these processes.

Overcoming drug-resistant cancer by a newly developed copper chelate through host-protective cytokine-mediated apoptosis

PURPOSE

Previously, we have synthesized and characterized a novel Cu(II) complex, copper N-(2-hydroxy acetophenone) glycinate (CuNG). Herein, we have determined the efficacy of CuNG in overcoming multidrug-resistant cancer using drug-resistant murine and human cancer cell lines.

EXPERIMENTAL DESIGN

Action of CuNG following single i.m. administration (5 mg/kg body weight) was tested in vivo on doxorubicin-resistant Ehrlich ascites carcinoma (EAC/Dox)-bearing mice and doxorubicin-resistant sarcoma 180-bearing mice. Tumor size, ascitic load, and survival rates were monitored at regular intervals. Apoptosis of cancer cells was determined by cell cycle analysis, confocal microscopy, Annexin V binding, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay ex vivo. IFN-gamma and tumor necrosis factor-alpha were assayed in the culture supernatants of in vivo and in vitro CuNG-treated splenic mononuclear cells from EAC/Dox-bearing mice and their apoptogenic effect was determined. Source of IFN-gamma and changes in number of T regulatory marker-bearing cells in the tumor site following CuNG treatment were investigated by flow cytometry. Supernatants of in vitro CuNG-treated cultures of peripheral blood mononuclear cells from different drug-insensitive cancer patients were tested for presence of the apoptogenic cytokine IFN-gamma and its involvement in induction of apoptosis of doxorubicin-resistant CEM/ADR5000 cells.

RESULTS

CuNG treatment could resolve drug-resistant cancers through induction of apoptogenic cytokines, such as IFN-gamma and/or tumor necrosis factor-alpha, from splenic mononuclear cells or patient peripheral blood mononuclear cells and reduce the number of T regulatory marker-bearing cells while increase infiltration of IFN-gamma-producing T cells in the ascetic tumor site.

CONCLUSION

Our results show the potential usefulness of CuNG in immunotherapy of drug-resistant cancers irrespective of multidrug resistance phenotype.

Systemic immune dysfunction in pancreatic cancer patients

BACKGROUND AND AIMS

We investigated the immune status in 32 pancreatic cancer patients (PC) in comparison with healthy controls (HC).

MATERIALS AND METHODS

Using flow cytometry, peripheral blood lymphocytes (PBL) were characterized by the expression of surface markers for T helper cells (CD4), T suppressor cells (CD8), B cells (CD19) and NK cells (CD56). The blastogenic response of PBL was analyzed after stimulation with concavalin A (ConA), phytohemagglutinin (PHA), pokeweed mitogen (PWM) and anti-CD3 antibodies. The serum levels of TNF-alpha, IL-1beta, IL-2, IL-10, IL-12, IL-18, IL-1RA, sIL-2R and TGF-beta were determined by ELISA.

RESULTS

No differences in the distribution of peripheral immunocytes in PC were found, whereas the blastogenic response of peripheral blood lymphocytes (PBL) after stimulation with PHA or anti-CD3 antibodies was significantly decreased in PC. In PC, we found reduced serum levels of IL-2 and significantly elevated levels of TNF-alpha, TGF-beta1, IL-10, IL-2R, IL-1beta and IL-1RA.

CONCLUSION

These data provide evidence for a systemic immune dysfunction in pancreatic cancer patients characterized by a shift towards a T helper cell type 2 cytokine profile, a significant elevation of substances related to T cell suppression and a reduced blastogenic response to PHA and anti-CD3 antibodies of PBL.