Surveillance against tumors—is it mainly immunological?

Increased cancer risk in HIV-infected individuals occupationally exposed to chemicals: Depression of p53 as the key driver

The growing exposure to occupational chemicals and the spread of human immunodeficiency virus (HIV) infection are major global health issues. However, there is little data on the carcinogenic risk profile of HIV-infected individuals who have been occupationally exposed to chemical mixtures. This study therefore investigated the levels of cancer risk biomarkers in HIV-infected individuals exposed to occupational chemicals, exploring the relationship between apoptotic regulatory and oxidative response markers as a measure of cancer risk. Study participants (mean age 38.35±0.72 years) were divided into four groups according to their HIV status and occupational chemical exposure: 62 HIV-positive exposed (HPE), 66 HIV-positive unexposed (HPU), 60 HIV-negative exposed (HNE), and 60 HIV-negative unexposed (HNU). Serum p53, β-cell lymphoma-2 (bcl2), 8-hydroxydeoxyguanosine (8-OHdG), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured using standard methods. Clusters of differentiation 4 (CD4+) T-lymphocytes were enumerated using flow cytometry. Serum p53 and bcl2 levels in HPE (0.91±0.11ng/ml and 122.37±15.77ng/ml) were significantly lower than HNU (1.49±0.15ng/ml and 225.52±33.67ng/ml) (p < 0.05), respectively. Wildtype p53 and bcl2 were positively and significantly correlated with 8-OHdG (r = 0.35, p<0.001; r = 0.36, p<0.001) and SOD (r = 0.38, p<0.001; r = 0.39, p<0.001). After controlling for gender, age, BMI, and cigarette smoking, both HIV status and SOD activity were significantly associated with wildtype p53 and bcl2 (p < 0.05). Malondialdehyde was significantly higher in the HPE (0.72 ± 0.01 mg/ml) than in the HNE (0.68 ± 0.01 mg/ml) and HNU (0.67 ± 0.01 mg/ml) groups (p < 0.05). The HPE group showed significantly lower CD4 counts than the HNE and HNU groups. Individuals who are HIV-infected and occupationally exposed to chemicals have a constellation of depressed immunity, elevated oxidative stress, and loss of tumour suppressive functions, which together intensify cancer risk, providing valuable scientific and public health bases for preventive measures in this vulnerable population.

Identification of a chemotherapy-associated gene signature for a risk model of prognosis in gastric adenocarcinoma through bioinformatics analysis

BACKGROUND

Over the past few years, the overall survival rate of patients with gastric adenocarcinoma who have received different chemotherapy regimens has increased. However, not all gastric cancer patients who receive chemotherapy have a longer survival. We need better predictive biomarkers. This study is to construct a new risk model of chemotherapy-associated genes in gastric adenocarcinoma (GA) for prognostication.

METHODS

RNA-seq data and clinical information of GSE26901 (containing 44 chemotherapy samples and 65 patients without chemotherapy) in Gene Expression Omnibus (GEO) and stomach adenocarcinoma (STAD, containing 360 cancer tissue samples and 50 paired normal tissue samples) in The Cancer Genome Atlas (TCGA) were selected for screening differentially expressed genes (DEGs). Multivariate Cox regression was conducted to screen prognosis-associated genes and its link to patients' prognosis were screened by least absolute shrinkage and selection operator (LASSO) regression analysis. Based on the key genes, a risk scoring equation for the prognosis model was established, and constructed survival prognosis model. The model was tested for predictive ability through training set (TCGA datasets) and validation set (GSE84437). The correlations of the risk score with clinical pathological features, immune score and drug sensitivity score were evaluated.

RESULTS

In total, 179 overlapping genes were obtained by screening DEGs. Univariate Cox analysis revealed 36 prognosis-related genes, and LASSO regression analysis revealed 8 key genes (KCNJ2, GATA5, CLDN1, SERPINE1, FCER2, PMEPA1, TMEM37 and CRTAC1). Kaplan-Meier (K-M) analysis uncovered a relatively short overall survival time in the high-risk group. The model was verified to possess favourable predictive ability. In addition, the nomogram model were demonstrated good predictability with area under the curve (AUC) for 1-5 years in training set were 0.78, 0.78, 0.76, 0.79 and 0.81. The high-risk group was less likely to get benefits from immunotherapy and less sensitive to cisplatin.

CONCLUSIONS

According to the results of our training set and validation set, the risk model based on the eight chemotherapy-related gene signatures predicting prognosis has certain predictive accuracy in predicting the survival of GA patients which can be a promising prognostic parameter for GA. However, its efficacy remains to be proved in clinical practice.

Correlation between Genes of the ceRNA Network and Tumor-Infiltrating Immune Cells and Their Biomarker Screening in Kidney Renal Clear Cell Carcinoma

This study aimed to using bioinformatics tools, qPCR, and the immunohistochemical analysis to find out factors related to the early diagnosis and prognosis of kidney renal clear cell carcinoma (KIRC). The expression profiles of lncRNA, miRNA, and mRNA of KIRC were downloaded from The Cancer Genome Atlas database. A ceRNA regulatory network was constructed based on the interaction between these three differentially expressed genes. The CIBERSORT deconvolution algorithm was used to analyze the differential distribution of 22 types of immune cells. The Kaplan–Meier survival and Cox analyses were used to screen genes of the ceRNA network and also immune cell subtypes related to the clinical and prognostic prediction of KIRC. Co-expression regulatory relationships were found among LINC01426, LINC00894, CCNA2, L1 cell adhesion molecule (L1CAM), and T follicular helper cells, which served as potential biomarkers. The results of quantitative reverse transcriptase-polymerase chain reaction showed that LINC01426 was upregulated while L1CAM was downregulated in KIRC, but no difference was found in the expression levels of LINC00894 and CCNA2 in cancer and adjacent samples. The immunohistochemical analysis showed that T follicular helper cells were more concentrated in core tissues and metastases of KIRC. In a word, co-expression relationships were found among LINC01426, L1CAM, and T follicular helper cells, and they may serve as biomarkers for early diagnosis and prognostic evaluation of KIRC.

The potential of gas plasma technology for targeting breast cancer

Despite therapeutic improvements in recent years, breast cancer remains an often fatal disease. In addition, breast cancer ulceration may occur during late stages, further complicating therapeutic or palliative interventions. In the past decade, a novel technology received significant attention in the medical field: gas plasma. This topical treatment relies on the partial ionization of gases that simultaneously produce a plethora of reactive oxygen and nitrogen species (ROS/RNS). Such local ROS/RNS overload inactivates tumour cells in a non-necrotic manner and was recently identified to induce immunogenic cancer cell death (ICD). ICD promotes dendritic cell maturation and amplifies antitumour immunity capable of targeting breast cancer metastases. Gas plasma technology was also shown to provide additive toxicity in combination with radio and chemotherapy and re-sensitized drug-resistant breast cancer cells. This work outlines the assets of gas plasma technology as a novel tool for targeting breast cancer by summarizing the action of plasma devices, the roles of ROS, signalling pathways, modes of cell death, combination therapies and immunological consequences of gas plasma exposure in breast cancer cells in vitro, in vivo, and in patient-derived microtissues ex vivo.

Immunomodulation: An immune regulatory mechanism in carcinoma therapeutics

Cancer has been generally related to the possession of numerous mutations which interrupt important signaling pathways. Nevertheless, deregulated immunological signaling is considered as one of the key factors associated with the development and progression of cancer. The signaling pathways operate as modular network with different components interacting in a switch-like fashion with two proteins interplaying between each other leading to direct or indirect inhibition or stimulation of down-stream factors. Genetic, epigenetic, and transcriptomic alterations maintain the pathological conduit of different signaling pathways via affecting diverse mechanisms including cell destiny. At present, immunotherapy is one of the best therapies opted for cancer treatment. The cancer immunotherapy strategy includes harnessing the specificity and killing mechanisms of the immunological system to target and eradicate malignant cells. Targeted therapies utilizing several little molecules including Galunisertib, Astragaloside-IV, Melatonin, and Jervine capable of regulating key signaling pathways can effectively help in the management of different carcinomas.

Site-specific metastasis: A cooperation between cancer cells and the metastatic microenvironment

The conclusion derived from the information provided in this review is that disseminating tumor cells (DTC) collaborate with the microenvironment of a future metastatic organ site in the establishment of organ‐specific metastasis. We review the basic principles of site‐specific metastasis and the contribution of the cross talk between DTC and the microenvironment of metastatic sites (metastatic microenvironment [MME]) to the establishment of the organ‐specific premetastatic niche; the targeted migration of DTC to the endothelium of the future organ‐specific metastasis; the transmigration of DTC to this site and the seeding and colonization of DTC in their future MME. We also discuss the role played by DTC‐MME interactions on tumor dormancy and on the differential response of tumor cells residing in different MMEs to antitumor therapy. Finally, we summarize some studies dealing with the effects of the MME on a unique site‐specific metastasis—brain metastasis.

Integrative analysis of immune microenvironment-related CeRNA regulatory axis in gastric cancer

This study aimed to identify significant immune microenvironment-related competing endogenous RNA (CeRNA) regulatory axis in gastric cancer (GC). Analysis of differentially expressed mRNAs (DEmRNAs), miRNAs (DEmiRNAs), and lncRNAs (DElncRNAs) was performed for the microarray datasets. After abundance analysis of immune cell's infiltration, immune-related mRNAs and lncRNAs were obtained. Meanwhile, according to the Pearson correlation coefficient between immune-related mRNAs and lncRNAs, the co-expression mRNA-lncRNA pairs were screened. Furthermore, the target genes of co-existance miRNAs were predicted, and miRNA-lncRNA pairs were identified. Finally, the lncRNA-miRNA and miRNA-mRNA relationship regulated by the same miRNA was screened. Combining with the co-expression relationship between lncRNA and mRNA, the CeRNA network was constructed. In abundance analysis of immune cell's infiltration, a total of eight immune cells were obtained, in addition, 83 immune-related DElncRNAs and 705 immune-related DEmRNAs were screened. KEGG pathway enrichment analysis showed that these mRNAs were mainly involved in PI3K-Akt signaling pathway and human papillomavirus infection, while lncRNA were relevant to gastric acid secretion. A total of 25 miRNAs were significantly associated with immune-related mRNAs, such as hsa-miR-148a-3p, hsa-miR-17-5p, and hsa-miR-25-3p. From the mRNA-miRNA-lncRNA CeRNA network, we observed that AC104389.28─miR-17-5─SMAD5 axis and LINC01133─miR-17-5p─PBLD axis played a crucial role in the development of GC. Furthermore, resting memory CD4 T cells and plasma cells were closely associated with the pathogenesis of GC, and these immune cells might be affected by the key genes. The present study identified key genes that associated with immune microenvironment in GC, providing potential molecular targets for immunotherapy of GC.

Actinidia chinensis Planch prevents proliferation and migration of gastric cancer associated with apoptosis, ferroptosis activation and mesenchymal phenotype suppression

Actinidia chinensis Planch (ACP) was the kiwifruit plant Chinese kiwifruit Actinidia chinensis Planch Root, which had been approved to be an anti-tumor drug widespread in clinical. However, the specific mechanism of ACP in resistance to gastric cancer remained unclear. Therefore, our study was dedicated to investigate the anti-proliferation and anti-migration effects of ACP on gastric cancer cells and its molecular mechanisms. Firstly, we utilized HPLC-MS to analyze the composition of ACP decoction, the results showed that ACP contained two main anti-tumor components, Ursolic acid and Oleanolic acid. The proliferation and migration ability of HGC-27 were examined by CCK-8 and cell scratch tests respectively. In addition, we also investigated HGC-27 cells apoptosis, mesenchymal phenotype and ferroptosis after ACP rat drug-containing serum (ACPs) treatment. EGFP-expressing lentiviral vectors were utilized to construct HGC-27 cells which containing green fluorescence. Then we take advantages of containing green fluorescence cells to establish a zebrafish xenograft model in vivo. The CCK-8 and cell scratch experiments verified that ACPs significantly inhibited proliferation and migration of HGC-27 in vitro. ACPs increased cells apoptosis rate, while were rescued by apoptosis inhibitor Z-VAD-FMK. Furthermore, ACPs downregulated the expression levels of Vimentin protein and Snail protein markedly. Intriguingly, ACPs increased the accumulation of ROS via inhibited the glutathione peroxidase 4 (GPx4) and xCT (SLC7A11) proteins, while were inhibited by Ferrostatin-1 (Fer-1) significantly. Furthermore, the zebrafish xenograft study further confirmed that administration of ACP suppressed the xenograft growth and metastasis of transplanted HGC-27 cells in vivo. In conclusion, ACP was a promising antineoplastic agent for the treatment of gastric cancer by regulating apoptosis, ferroptosis and mesenchymal phenotype.

Identification of Further Components of an Anticancer Defense System Composed of Small Molecules Present in the Serum

BACKGROUND

Earlier we assumed that small molecules selectively accumulated in cancer cells might have a role in a defense system capable of killing cancer cells. We reported earlier that an experimentally selected mixture of substances present in the serum ("active mixture," AM) shows a selective toxic effect in vitro and in vivo on various cancer cells. In this study we investigated additional compounds found in the serum to further expand our knowledge of this defense system.

MATERIALS AND METHODS

The cell proliferation was detected by WST-1 assay. The mRNA level of the examined genes was measured by quantitative real-time polymerase chain reaction.

RESULTS

We identified 34 additional compounds (l-amino acid metabolites, phenolic acids, d-amino acids, keto acids, etc.), which when applied in a per se nontoxic concentration are able to enhance the effect of AM. The combination of the mixture of these newly identified substances (new mixture, NM) with AM produced a significantly higher cancer cell growth inhibitory effect than NM or AM applied alone on HeLa, MCF-7, PC-3, Caco-2, HepG2, and 4T1 cancer cell lines, and more efficiently induced the expression of certain proapoptotic genes in HeLa cells. Any given combinations of the individual compounds of AM and NM always produced an increased effect compared with AM alone.

CONCLUSIONS

The newly identified compounds significantly enhance the anticancer effect of AM. The components of AM and NM together may form part of a defense system capable of killing cancer cells and are worthy of further investigation.

Immune signature profiling identified prognostic factors for gastric cancer

Objective

Tumor microenvironment, especially the host immune system, plays a pivotal role in tumor initiation and progression. Profiling of immune signature within tumor might uncover biomarkers for targeted therapies and clinical outcomes. However, systematic analysis of immune-related genes in gastric cancer (GC) has not been reported.

Methods

Expressions of a total of 718 immune-related genes were generated in 372 stomach adenocarcinoma (STAD) patients from The Cancer Genome Atlas (TCGA) database using RNA-sequencing data. Integrated bioinformatics analyses were performed to identify prognostic factors as well.

Results

Survival analyses revealed 73 genes, which were significantly associated with patient’s overall survival (OS). Taken together with clinicopathological parameters, we established a predictive model, containing 10 immune-related genes, which were NRP1, C6, CXCR4, LBP, PNMA1, TLR5, ITGA6, MICB, PBK and TNFRSF18, with powerful efficiency in distinguishing satisfactory or poor survival of STAD patients. Moreover, the top 3 ranked prognostic genes, NRP1, TGFβ2 and MFGE8, were also significantly associated with patient’s OS by an independent validation achieved from Kaplan-Meier plotter database.

Conclusions

We profiled prognostic immune signature and established prognostic predictive model for GC, which could reflect immune disorders within tumor microenvironment, and also may provide novel predictive and therapeutic targets for GC patients in the near future.

A history of exploring cancer in context

The concept that progression of cancer is regulated by interactions of cancer cells with their microenvironment was postulated by Stephen Paget over a century ago. Contemporary tumour microenvironment (TME) research focuses on the identification of tumour-interacting microenvironmental constituents, such as resident or infiltrating non-tumour cells, soluble factors and extracellular matrix components, and the large variety of mechanisms by which these constituents regulate and shape the malignant phenotype of tumour cells. In this Timeline article, we review the developmental phases of the TME paradigm since its initial description. While illuminating controversies, we discuss the importance of interactions between various microenvironmental components and tumour cells and provide an overview and assessment of therapeutic opportunities and modalities by which the TME can be targeted.

A comprehensive review of pesticides and the immune dysregulation: mechanisms, evidence and consequences

Nowadays, in many communities, there is a growing concern about possible adverse effects of pesticides on human health. Reports indicate that during environmental or occupational exposure, pesticides can exert some intense adverse effects on human health through transient or permanent alteration of the immune system. There is evidence on the relation between pesticide-induced immune alteration and prevalence of diseases associated with alterations of the immune response. In the present study, direct immunotoxicity, endocrine disruption and antigenicity have been introduced as the main mechanisms working with pesticides-induced immune dysregulation. Moreover, the evidence on the relationship between pesticide exposure, dysregulation of the immune system and predisposition to different types of psychiatric disorders, cancers, allergies, autoimmune and infectious diseases are criticized.

Prognostic implications of immunosuppressive protein expression in tumors as well as immune cell infiltration within the tumor microenvironment in gastric cancer

BACKGROUND

There are few data on the clinical implications of immunosuppressive protein expression in tumors and immune cell infiltration within the tumor microenvironment in patients with gastric cancer (GC).

METHODS

In this study, 243 patients with curatively resected GC were included. The levels of immunosuppressive protein expression [programmed cell death 1 ligand 1 (PD-L1), cytotoxic T-lymphocyte antigen 4 (CTLA-4), and indoleamine 2,3-dioxygenase (IDO)] in tumors and the densities of immune cells [CD3(+), CD4(+), CD8(+), or PD-1(+) cells] within the tumor microenvironment were measured using immunohistochemical analysis.

RESULTS

Positive PD-L1, CTLA-4, and IDO expression was observed in 43.6, 65.8, and 47.7% of the patients, respectively. Expression of PD-L1, CTLA-4, and IDO was related to less advanced stage, intestinal type, and well/moderately differentiated adenocarcinoma (P < 0.05). PD-L1 expression was related to better disease-free survival (DFS) and overall survival (OS) in GC [PD-L1(+) vs. PD-L1(-) tumors: 5-year DFS rate, 82.6 vs. 66.9%; 5-year OS rate, 83.0 vs. 69.1% (P values <0.05)]. Survival outcomes were also better in patients with a higher density of CD3(+) cells within the tumor microenvironment than in those with a lower density of CD3(+) cells [5-year DFS rate, 80.9 vs. 67.0%; 5-year OS rate, 82.5 vs. 68.0% (P values <0.05)]. In multivariate analysis, these two immune markers had a prognostic impact on survival, independent of other clinical variables.

CONCLUSIONS

GC patients with immunosuppressive protein expression (PD-L1, CTLA-4, or IDO) had distinct clinicopathological characteristics. PD-L1(+) expression and a high-CD3 tumor microenvironment are favorable prognostic markers in GC.

Tissue prognostic biomarkers in primary cutaneous melanoma

Cutaneous melanoma (CM) causes the greatest number of skin cancer-related deaths worldwide. Predicting CM prognosis is important to determine the need for further investigation, counseling of patients, to guide appropriate management (particularly the need for postoperative adjuvant therapy), and for assignment of risk status in groups of patients entering clinical trials. Since recurrence rate is largely independent from stages defined by morphological and morphometric criteria, there is a strong need for identification of additional robust prognostic factors to support decision-making processes. Most data on prognostic biomarkers in melanoma have been evaluated in tumor tissue samples by conventional morphology and immunohistochemistry (IHC) as well as DNA and RNA analyses. In the present review, we critically summarize main high-quality studies investigating IHC-based protein biomarkers of melanoma outcome according to Reporting Recommendations for Tumor Marker Prognostic Studies (REMARK)-derived criteria. Pathways have been classified and conveyed in the "biologic road" previously described by Hanahan and Weinberg. Data derived from genomic and transcriptomic technologies have been critically reviewed to better understand if any of investigated proteins or gene signatures should be incorporated into clinical practice or still remain a field of melanoma research. Despite a wide body of research, no molecular prognostic biomarker has yet been translated into clinical practice. Conventional tissue biomarkers, such as Breslow thickness, ulceration, mitotic rate and lymph node positivity, remain the backbone prognostic indicators in melanoma.

The metastatic microenvironment: lung-derived factors control the viability of neuroblastoma lung metastasis

Recent data suggest that the mechanisms determining whether a tumor cell reaching a secondary organ will enter a dormant state, progress toward metastasis, or go through apoptosis are regulated by the microenvironment of the distant organ. In neuroblastoma, 60-70% of children with high-risk disease will ultimately experience relapse due to the presence of micrometastases. The main goal of this study is to evaluate the role of the lung microenvironment in determining the fate of neuroblastoma lung metastases and micrometastases. Utilizing an orthotopic mouse model for human neuroblastoma metastasis, we were able to generate two neuroblastoma cell populations-lung micrometastatic (MicroNB) cells and lung macrometastatic (MacroNB) cells. These two types of cells share the same genetic background, invade the same distant organ, but differ in their ability to create metastasis in the lungs. We hypothesize that factors present in the lung microenvironment inhibit the propagation of MicroNB cells preventing them from forming overt lung metastasis. This study indeed shows that lung-derived factors significantly reduce the viability of MicroNB cells by up regulating the expression of pro-apoptotic genes, inducing cell cycle arrest and decreasing ERK and FAK phosphorylation. Lung-derived factors affected various additional progression-linked cellular characteristics of neuroblastoma cells, such as the expression of stem-cell markers, morphology, and migratory capacity. An insight into the microenvironmental effects governing neuroblastoma recurrence and progression would be of pivotal importance as they could have a therapeutic potential for the treatment of neuroblastoma residual disease.

Regulation of COX2 expression in mouse mammary tumor cells controls bone metastasis and PGE2-induction of regulatory T cell migration

Background

The targeting of the immune system through immunotherapies to prevent tumor tolerance and immune suppression are at the front lines of breast cancer treatment and research. Human and laboratory studies have attributed breast cancer progression and metastasis to secondary organs such as the bone, to a number of factors, including elevated levels of prostaglandin E2 (PGE2) and the enzyme responsible for its production, cyclooxygenase 2 (COX2). Due to the strong connection of COX2 with immune function, we focused on understanding how variance in COX2 expression manipulates the immune profile in a syngeneic, and immune-competent, mouse model of breast cancer. Though there have been correlative findings linking elevated levels of COX2 and Tregs in other cancer models, we sought to elucidate the mechanisms by which these immuno-suppressive cells are recruited to breast tumor and the means by which they promote tumor tolerance.

Methodology/Principal Findings

To elucidate the mechanisms by which exacerbated COX2 expression potentiates metastasis we genetically manipulated non-metastatic mammary tumor cells (TM40D) to over-express COX2 (TM40D-COX2). Over-expression of COX2 in this mouse breast cancer model resulted in an increase in bone metastasis (an observation that was ablated following suppression of COX2 expression) in addition to an exacerbated Treg recruitment in the primary tumor. Interestingly, other immune-suppressive leukocytes, such as myeloid derived suppressor cells, were not altered in the primary tumor or the circulation. Elevated levels of PGE2 by tumor cells can directly recruit CD4+CD25+ cells through interactions with their EP2 and/or EP4 receptors, an effect that was blocked using anti-PGE2 antibody. Furthermore, increased Treg recruitment to the primary tumor contributed to the greater levels of apoptotic CD8+ T cells in the TM40D-COX2 tumors.

Conclusion/Significance

Due to the systemic effects of COX2 inhibitors, we propose targeting specific EP receptors as therapeutic interventions to breast cancer progression.

Molecular Markers with Predictive and Prognostic Relevance in Lung Cancer

Lung cancer accounts for the majority of cancer-related deaths worldwide of which non-small-cell lung carcinoma alone takes a toll of around 85%. Platinum-based therapy is the stronghold for lung cancer at present. The discovery of various molecular alterations that underlie lung cancer has contributed to the development of specifically targeted therapies employing specific mutation inhibitors. Targeted chemotherapy based on molecular profiling has shown great promise in lung cancer treatment. Various molecular markers with predictive and prognostic significance in lung cancer have evolved as a result of advanced research. Testing of EGFR and Kras mutations is now a common practice among community oncologists, and more recently, ALK rearrangements have been added to this group. This paper discusses various predictive and prognostic markers that are being investigated and have shown significant relevance which can be exploited for targeted treatment in lung cancer.

A mixture of amino acids and other small molecules present in the serum suppresses the growth of murine and human tumors in vivo

Previously we have hypothesized that the small molecules which are selectively accumulated in cancer cells might participate in a non-immunological antitumor surveillance mechanism. We demonstrated earlier that a mixture of experimentally selected substances (“active mixture”, AM: l-arginine, l-histidine, l-methionine, l-phenylalanine, l-tyrosine, l-tryptophan, l-ascorbate, d-biotin, pyridoxine, riboflavin, adenine, l(-)malate) possesses a selective toxic effect in vitro on a variety of tumor cell lines, and we have shown that the AM selectively induces apoptosis of cancer cells in vitro. To explore the in vivo significance of our earlier findings we examined the antitumor effect of AM in Colon 26 murine colorectal adenocarcinoma, B16 murine melanoma, MXT murine mammary carcinoma, S180 murine sarcoma, P388 murine lymphoid leukemia, HL-60 human promyeloid leukemia, PC-3 human prostate carcinoma, and HT-29 human colon carcinoma tumor models. Treatment of tumor bearing mice with AM inhibited the growth of the tumors investigated, with an inhibitory effect ranging from 40 to 69%. The AM had a comparable antitumor effect with 5-fluorouracil and cisplatin in the Colon-26 tumor model, and combined treatment with AM and 5-fluorouracil or cisplatin resulted in an enhanced tumor growth inhibitory effect. The AM induced apoptosis through the mitochondrial pathway and induced G1 arrest in PC-3 cells and increased the number of apoptotic cells in PC-3 xenografts. These findings suggest that the AM might offer an interesting perspective in the treatment of cancer and in combination with other treatments may offer hope for a more effective cancer therapy.

The impact of multiple malignancies on patients with bladder carcinoma: a population-based study using the SEER database

Purpose. To date, no study has examined a population-based registry to determine the impact of multiple malignancies on survival of bladder cancer patients. Our experience suggests that bladder cancer patients with multiple malignancies may have relatively positive outcomes. Materials & Methods. We utilized data from the Surveillance Epidemiology and End Results (SEERs) database to examine survival between patients with only bladder cancer (BO) and with bladder cancer and additional cancer(s) antecedent (AB), subsequent (BS), or antecedent and subsequent to bladder cancer (ABS). Results. Analyses demonstrated diminished survival among AB and ABS cohorts. However, when cohorts were substratified by stage, patients in the high-stage BS cohort appeared to have a survival advantage over high-stage BO patients. Conclusions. Bladder cancer patients with multiple malignancies have diminished survival. The survival advantage of high-stage BS patients is likely a statistical phenomenon. Such findings are important to shape future research and to improve our understanding of patients with multiple malignancies.

Cancer dormancy: lessons from a B cell lymphoma and adenocarcinoma of the prostate

Cancer dormancy delineates a situation in which residual tumor cells persist in a patient with no apparent clinical symptoms. Although the precise mechanisms underlying cancer dormancy have not been explained, experimental models have provided some insights into the factors that might be involved in the induction and maintenance of a tumor dormant state. The authors of the present chapter studied a murine B cell lymphoma that can be made dormant when interacting with antibodies directed against the idiotype on its immunoglobulin Ig receptor. This experimental model of antibody-induced dormancy enabled the isolation and characterization of dormant lymphoma cells. The results indicated that anti-Ig antibodies activate growth-inhibiting signals that induced cycle arrest and apoptosis. This process appeared to be balanced by the growth of the tumor cells such that the tumor did not expand. In contrast, antibodies against HER-2expressed on prostate adenocarcinoma (PAC) cells were not growth inhibitory. However, an immunotoxin (IT) prepared by conjugating HER-2 to the A-chain of ricin (RTA) was internalized by PAC cells, followed by induction of cycle arrest and apoptotic death. Infusion of HER-2-specific IT into PAC-bearing immunodeficient mice did not eradicate the tumor but retained it dormant over an extended period of time. Hence, certain aspects of signaling receptors expressed on cancer can be manipulated by antibodies to induce and maintain a tumor dormant state.

Expansion and activation of natural killer cells for cancer immunotherapy

Natural killer (NK) cells can kill a wide range of cancer cells and are a promising tool for cell therapy of cancer. NK cells cytotoxicity is regulated by a balance between stimulatory and inhibitory signals. Interleukin-2 is known to increase NK cell cytotoxicity. Although many cytokines have been studied in efforts to induce durable NK cell expansions, most reports indicate a rather modest effect and the requirement for additional stimuli. We found that contact with the K562 myeloid leukemia cell line, genetically modified to express a membrane-bound form of interleukin-15 and the ligand for the costimulatory molecule 4-1BB, induced vigorous expansion of NK cells from peripheral blood. Based on these findings, we developed a method for large-scale clinical-grade expansion of NK cells. This method is currently used to expand allogeneic NK cells for infusion in patients with leukemia and solid tumors. We here summarize methods for expansion and activation of NK cells from human peripheral blood mononuclear cells as well as clinical-scale methods to produce NK cells for immunotherapy under Current Good Manufacturing Practices (cGMP) conditions.

Tumor immune surveillance defect of X-linked severe combined immunodeficiency is not Epstein-Barr virus specific

Immunodeficient patients are at an increased risk of developing Epstein-Barr virus (EBV) associated lymphomas. We report a patient with X-linked severe combined immunodeficiency (X-SCID), who presented with an EBV-negative, B-cell non-Hodgkin lymphoma. The tumor did not resolve with chemotherapy or rituximab, but only after recovery of functional donor T-cells cell following hematopoietic stem cell transplantation (HSCT). This case illustrates that the cancer predilection associated with immunodeficient hosts may not be a specific immune defect in the recognition of viral specific antigens, and it could be a defect in immune surveillance necessary for elimination of cells with abnormalities in proliferation, function and/or apoptosis.

Cancer immunoediting from immune surveillance to immune escape

Cancer immune surveillance is considered to be an important host protection process to inhibit carcinogenesis and to maintain cellular homeostasis. In the interaction of host and tumour cells, three essential phases have been proposed: elimination, equilibrium and escape, which are designated the 'three E's'. Several immune effector cells and secreted cytokines play a critical role in pursuing each process. Nascent transformed cells can initially be eliminated by an innate immune response such as by natural killer cells. During tumour progression, even though an adaptive immune response can be provoked by antigen-specific T cells, immune selection produces tumour cell variants that lose major histocompatibility complex class I and II antigens and decreases amounts of tumour antigens in the equilibrium phase. Furthermore, tumour-derived soluble factors facilitate the escape from immune attack, allowing progression and metastasis. In this review, the central roles of effector cells and cytokines in tumour immunity, and the escape mechanisms of tumour cells during tumour progression are discussed.

Cancer immunoediting from immune surveillance to immune escape

Cancer immune surveillance is considered to be an important host protection process to inhibit carcinogenesis and to maintain cellular homeostasis. In the interaction of host and tumour cells, three essential phases have been proposed: elimination, equilibrium and escape, which are designated the 'three E's'. Several immune effector cells and secreted cytokines play a critical role in pursuing each process. Nascent transformed cells can initially be eliminated by an innate immune response such as by natural killer cells. During tumour progression, even though an adaptive immune response can be provoked by antigen-specific T cells, immune selection produces tumour cell variants that lose major histocompatibility complex class I and II antigens and decreases amounts of tumour antigens in the equilibrium phase. Furthermore, tumour-derived soluble factors facilitate the escape from immune attack, allowing progression and metastasis. In this review, the central roles of effector cells and cytokines in tumour immunity, and the escape mechanisms of tumour cells during tumour progression are discussed.

The janus face of immunosuppression - de novo malignancy after renal transplantation: the experience of the Transplantation Center Munich

After decades of successful organ transplantation clinicians continue to be troubled by the increasing incidence of cancers under maintenance immunosuppression. In this study, we examined rates of malignancies in 2419 renal transplant recipients transplanted in our institution between 1978 and 2005. In renal transplant recipients the cumulative incidence of cancer after 25 years was 49.3% for all tumors and 39.7% excluding non-melanoma skin cancers, compared with 21% for a normal sex- and age-matched population. The most frequent tumors observed were non-melanoma skin cancers (20.5%), kidney cancers (12.0%), and cancers of the pharynx, larynx, or oral cavity (8.2%). The general increase of cancer risk was 4.3-fold. Independent risk factors for the development of a tumor were male gender, older recipient age, the presence of preformed antibodies before transplantation, and the time on immunosuppression. Interestingly, the use of IL-2-receptor antagonists significantly reduced the tumor risk of transplant recipients. The tumor risk between immunosuppressive drugs typically used for maintenance immunosuppression was not significantly different. However, mammalian target of rapamycin (mTOR) inhibitor-based immunosuppressive protocols showed a clear tendency for lower malignancy rates. De novo malignancies following renal transplantation represent a serious problem endangering the prognosis of otherwise successfully transplanted patients. Future studies will have to address whether optimized immunosuppressive regimens including mTOR-inhibitors are capable of reducing the incidence or preventing the development of posttransplant malignancies.

Alternative production of Bcl-2 and Bax by tumor cells determines the rates of in vivo tumor progression: Suggested mechanisms

The hypothesis tested in the study suggests that mechanisms of the earlier described delayed or accelerated tumor progression may be regulated by the antiapoptotic and proapoptotic cellular programs activated in stress reactions of transformed cells to the host normal cellular environment. Therefore, spontaneously transformed hamster cell line STHE, its bcl-2-transduced line STHE-Bcl-2, and 64 of their descendant tumor cell variants naturally selected in two in vivo regimes (local tumor growth versus dissemination) were examined. The role of Bcl-2 and the possible activation of endogenous death-signaling Bax, Ras, and HSP90/HSP70 stress proteins in STHE (Bcl-2+/-) tumor cell variants were studied in dynamics of in vivo tumor progression. The data demonstrate: (1) Immediate in vivo activation of Bax and of HSP90/HSP70 stress proteins in disseminated STHE cells on the background of accelerated tumor progression; (2) No immediate activation of Bax and the gradual downregulation of Bcl-2 in STHE-Bcl-2 cells on the background of delayed tumor progression; (3) Alternative and mutually suppressive character of Bcl-2 and Bax expression in both regimes of tumor progression; (4) In the later stages of tumor progression, the regular transit of the initial Bcl-2 antiapoptotic, Bax-suppressing program, and the delayed tumor progression towards Bcl-2 loss, activation of Bax, and acceleration of tumor progression. Thus, the delay of tumor progression is apparently determined by the ability of Bcl-2-expressing tumor cells to extinguish the cell-damaging environmental stress signals and Bax activation, while its acceleration correlates with Bcl-2 loss, activation of proapoptotic Bax, and tumor cells damage.

Liver immunity and tumour surveillance

Adult liver has a complex defence system that is critical in protection against infectious challenge. Its role in tumour surveillance is poorly understood. Because of its location, function and complex blood supply, the liver will be exposed to metastatic cells generated anywhere else in the body. Moreover, the role of the liver in detoxification can result in the generation of products with carcinogenic properties. It should not be surprising, then, to discover that the liver has a specialized immune system tailored to protect against and respond to significant immunological challenge, particularly metastasis and malignancy. This tumour surveillant role is the focus of this review.

Thyroid cancer and the immune system: a model for effective immune surveillance

Differentiated thyroid cancers, including papillary and follicular variants, are a useful model with which to examine interactions between cancer and the immune system. Differentiated thyroid cancers are detected in only 20,000 individuals annually in the USA, but thyroid microcarcinomas (< 1 cm in diameter) are far more common. This suggests that the immune system might restrain the growth of these microcarcinomas. On the clinical level, patients with lymphocytes that infiltrate into papillary thyroid cancer have improved survival, supporting the notion that immune system activation might improve this. Together, these observations suggest that the growth and distant spread of thyroid carcinoma are suppressed by mechanisms of immune surveillance, possibly involving lymphocytes, macrophages and their secreted products. In this review, we examine the general hypothesis of immune surveillance and the data pertaining to the roles of lymphocytes, dendritic cells and cytokines in the immune response against thyroid cancers.

Is there a role for immunotherapy in hepatocellular carcinoma?

Incidence of hepatocellular carcinoma has been rising in the last two decades because of the wide exposure to hepatitis C virus during 1960s and 1970s. Improvement in treatment has been achieved by local ablative therapies, however because of early recurrence and lack of effective chemotherapies, alternative treatments based on stimulation of the anti-tumour immune response could represent new strategies to control hepatocellular carcinoma spread and recurrence. Proof of principle of an effective immunotherapy has been achieved for other solid tumours such as melanoma and several results could be transferred to the immunotherapy of hepatocellular carcinoma. Specific tumour antigens have been identified in hepatocellular carcinoma, such as cancer testis antigens expressed in a large part of hepatocellular carcinomas and alpha-fetoprotein that has been already employed in clinical trials demonstrating immunogenicity without however significant clinical efficacy. Better results have been achieved by non-antigen-specific immunotherapies that demonstrated improvement in recurrence and recurrence-free survival in patients undergoing surgical resection for hepatocellular carcinoma. Passive immunotherapy and targeted therapies blocking tumour cell receptors or enzymatic pathways are already in the clinic for other malignancies and the near future will see these new treatments applied to hepatocellular carcinoma patients along with the development of efficacious active immunotherapies aimed at reducing disease recurrence and improving survival.

The tumor microenvironment in the post-PAGET era

The research area of tumor microenvironment is considered, at present, to be an important factor in tumorigenesis and especially in tumor progression. The present mini review is focused on three principles characterizing the nature of the tumor microenvironment. We first discuss the regulatory functions of the tumor microenvironment and the complexity of the combinatorial signaling pathways operating in it. We then address the aspect that the tumor microenvironment incorporates both pro and anti malignancy factors and that a balance between these factors regulates tumor progression. Thirdly we provide evidence that the non-tumor cells in the tumor microenvironment and their products may be different from those of their counterparts residing in non-tumor microenvironments. The conclusion of this mini review is that the tumor microenvironment, by exerting regulatory functions and selective pressures drives cancer cells into one of several molecular evolution pathways thereby determining and shaping their malignancy phenotype.

DNA Damage and Tumor Surveillance: One Trigger for Two Pathways

Biological evolution ensures that several backup mechanisms always exist to prevent the failure of cellular processes of critical importance for life. This notion applies to processes aimed at preventing cancer development. Recent research suggests that the DNA damage response, activated in one of the earliest cellular responses to transformation, may elicit two independent tumor surveillance mechanisms. The first, and most well known, is activation of the proapoptotic molecule p53 and subsequent cellular suicide. The second, reported in a recent study, is induction of the expression of ligands for the activating immune receptor NKG2D. That DNA damage induces two independent tumor surveillance responses demonstrates how one tumor surveillance mechanism may be assisted by another to secure efficient protection against early tumorigenesis. The results also support the immunosurveillance theory of cancer and suggest that it may operate at very early stages of tumorigenesis.