Fas-mediated killing of primary prostate cancer cells is increased by mitoxantrone and docetaxel

Pre-existing cell subpopulations in primary prostate cancer tumors display surface fingerprints of docetaxel-resistant cells

PURPOSE

Docetaxel resistance is a significant obstacle in the treatment of prostate cancer (PCa), resulting in unfavorable patient prognoses. Intratumoral heterogeneity, often associated with epithelial-to-mesenchymal transition (EMT), has previously emerged as a phenomenon that facilitates adaptation to various stimuli, thus promoting cancer cell diversity and eventually resistance to chemotherapy, including docetaxel. Hence, understanding intratumoral heterogeneity is essential for better patient prognosis and the development of personalized treatment strategies.

METHODS

To address this, we employed a high-throughput single-cell flow cytometry approach to identify a specific surface fingerprint associated with docetaxel-resistance in PCa cells and complemented it with proteomic analysis of extracellular vesicles. We further validated selected antigens using docetaxel-resistant patient-derived xenografts in vivo and probed primary PCa specimens to interrogate of their surface fingerprint.

RESULTS

Our approaches revealed a 6-molecule surface fingerprint linked to docetaxel resistance in primary PCa specimens. We observed consistent overexpression of CD95 (FAS/APO-1), and SSEA-4 surface antigens in both in vitro and in vivo docetaxel-resistant models, which was also observed in a cell subpopulation of primary PCa tumors exhibiting EMT features. Furthermore, CD95, along with the essential enzymes involved in SSEA-4 synthesis, ST3GAL1, and ST3GAL2, displayed a significant increase in patients with PCa undergoing docetaxel-based therapy, correlating with poor survival outcomes.

CONCLUSION

In summary, we demonstrate that the identified 6-molecule surface fingerprint associated with docetaxel resistance pre-exists in a subpopulation of primary PCa tumors before docetaxel treatment. Thus, this fingerprint warrants further validation as a promising predictive tool for docetaxel resistance in PCa patients prior to therapy initiation.

Receptors of immune cells mediates recognition for tumors

Over the last few decades, the immune system has been steered toward eradication of cancer cells with the help of cancer immunotherapy. T cells, B cells, monocytes/macrophages, dendritic cells, T-reg cells, and natural killer (NK) cells are some of the numerous immune cell types that play a significant part in cancer cell detection and reduction of inflammation, and the antitumor response. Briefly stated, chimeric antigen receptors, adoptive transfer and immune checkpoint modulators are currently the subjects of research focus for successful immunotherapy-based treatments for a variety of cancers. This chapter discusses ongoing investigations on the mechanisms and recent developments by which receptors of immune cells especially that of lymphocytes and monocytes/macrophages regulate the detection of immune system leading to malignancies. We will also be looking into the treatment strategies based on these mechanisms.

NK Cells in the Tumor Microenvironment as New Potential Players Mediating Chemotherapy Effects in Metastatic Melanoma

Until the last decade, chemotherapy was the standard treatment for metastatic cutaneous melanoma, even with poor results. The introduction of immune checkpoints inhibitors (ICIs) radically changed the outcome, increasing 5-year survival from 5% to 60%. However, there is still a large portion of unresponsive patients that would need further therapies. NK cells are skin-resident innate cytotoxic lymphocytes that recognize and kill virus-infected as well as cancer cells thanks to a balance between inhibitory and activating signals delivered by surface molecules expressed by the target. Since NK cells are equipped with cytotoxic machinery but lack of antigen restriction and needing to be primed, they are nowadays gaining attention as an alternative to T cells to be exploited in immunotherapy. However, their usage suffers of the same limitations reported for T cells, that is the loss of immunogenicity by target cells and the difficulty to penetrate and be activated in the suppressive tumor microenvironment (TME). Several evidence showed that chemotherapy used in metastatic melanoma therapy possess immunomodulatory properties that may restore NK cells functions within TME. Here, we will discuss the capability of such chemotherapeutics to: i) up-regulate melanoma cells susceptibility to NK cell-mediated killing, ii) promote NK cells infiltration within TME, iii) target other immune cell subsets that affect NK cells activities. Alongside traditional systemic melanoma chemotherapy, a new pharmacological strategy based on nanocarriers loaded with chemotherapeutics is developing. The use of nanotechnologies represents a very promising approach to improve drug tolerability and effectiveness thanks to the targeted delivery of the therapeutic molecules. Here, we will also discuss the recent developments in using nanocarriers to deliver anti-cancer drugs within the melanoma microenvironment in order to improve chemotherapeutics effects. Overall, we highlight the possibility to use standard chemotherapeutics, possibly delivered by nanosystems, to enhance NK cells anti-tumor cytotoxicity. Combined with immunotherapies targeting NK cells, this may represent a valuable alternative approach to treat those patients that do not respond to current ICIs.

Effects of neoadjuvant therapies on genetic regulation of targeted pathways in ER+ primary ductal breast carcinoma: A meta-analysis of microarray datasets

Breast cancer arises as a result of multiple interactions between environmental and genetic factors. Conventionally, breast cancer is treated based on histopathological and clinical features. DNA technologies like the human genome microarray are now partially integrated into clinical practice and are used for developing new "personalized medicines" and "pharmacogenetics" for improving the efficiency and safety of cancer medications. We investigated the effects of four established therapies-for ER+ ductal breast cancer-on the differential gene expression. The therapies included single agent tamoxifen, two-agent docetaxel and capecitabine, or combined three-agents CAF (cyclophosphamide, doxorubicin, and fluorouracil) and CMF (cyclophosphamide, methotrexate, and fluorouracil). Genevestigator 8.1.0 was used to compare five datasets from patients with infiltrating ductal carcinoma, untreated or treated with selected drugs, to those from the healthy control. We identified 74 differentially expressed genes involved in three pathways, i.e., apoptosis (extrinsic and intrinsic), oxidative signaling, and PI3K/Akt signaling. The treatments affected the expression of apoptotic genes (TNFRSF10B [TRAIL], FAS, CASP3/6/7/8, PMAIP1 [NOXA], BNIP3L, BNIP3, BCL2A1, and BCL2), the oxidative stress-related genes (NOX4, XDH, MAOA, GSR, GPX3, and SOD3), and the PI3K/Akt pathway gene (ERBB2 [HER2]). Breast cancer treatments are complex with varying drug responses and efficacy among patients. This necessitates identifying novel biomarkers for predicting the drug response, using available data and new technologies. GSR, NOX4, CASP3, and ERBB2 are potential biomarkers for predicting the treatment response in primary ER+ ductal breast carcinoma.

In vitro culture with gemcitabine augments death receptor and NKG2D ligand expression on tumour cells

Much effort has been made to try to understand the relationship between chemotherapeutic treatment of cancer and the immune system. Whereas much of that focus has been on the direct effect of chemotherapy drugs on immune cells and the release of antigens and danger signals by malignant cells killed by chemotherapy, the effect of chemotherapy on cells surviving treatment has often been overlooked. In the present study, tumour cell lines: A549 (lung), HCT116 (colon) and MCF-7 (breast), were treated with various concentrations of the chemotherapeutic drugs cyclophosphamide, gemcitabine (GEM) and oxaliplatin (OXP) for 24 hours in vitro. In line with other reports, GEM and OXP upregulated expression of the death receptor CD95 (fas) on live cells even at sub-cytotoxic concentrations. Further investigation revealed that the increase in CD95 in response to GEM sensitised the cells to fas ligand treatment, was associated with increased phosphorylation of stress activated protein kinase/c-Jun N-terminal kinase and that other death receptors and activatory immune receptors were co-ordinately upregulated with CD95 in certain cell lines. The upregulation of death receptors and NKG2D ligands together on cells after chemotherapy suggest that although the cells have survived preliminary treatment with chemotherapy they may now be more susceptible to immune cell-mediated challenge. This re-enforces the idea that chemotherapy-immunotherapy combinations may be useful clinically and has implications for the make-up and scheduling of such treatments.

Cytoskeletal reorganization and cell death in mitoxantrone-treated lung cancer cells

The aim of this study was to investigate the cytotoxic effect of mitoxantrone on two human non-small cell lung cancer cell lines, A549 (p53+) and H1299 (p53-). To our knowledge, this is the first study to evaluate the impact of MXT on the organization of cytoskeletal proteins. Analyses were performed using fluorescence and transmission electron microscopy, spectrophotometric techniques, flow cytometry and Western blotting. It was shown that H1299 cells are significantly more sensitive to mitoxantrone than the A549 cell line, and that the growth-inhibitory effect of the drug is dose-dependent only after longer incubation. The observed presence of ring-like microtubule structures and mitochondria surrounding the nuclei of H1299 cells could be a manifestation of increased tubulin polymerization requiring large amounts of energy, whereas the loss of actin stress fibers was presumably not the cause but rather the consequence of cell death induction. Treatment with mitoxantrone also led to the appearance of structures resembling agresomes in H1299 cells and to nucleolar segregation in both cell lines. It was demonstrated that cells arrested in the S phase were most susceptible to cell death induction, and that triggered intracellular changes led mainly to apoptosis. High concentrations induced necrosis and some H1299 cells exhibited morphological features of mitotic catastrophe.

Mitoxantrone, More than Just Another Topoisomerase II Poison

Mitoxantrone is a synthetic anthracenedione originally developed to improve the therapeutic profile of the anthracyclines and is commonly applied in the treatment of breast and prostate cancers, lymphomas, and leukemias. A comprehensive overview of the drug's molecular, biochemical, and cellular pharmacology is presented here, beginning with the cardiotoxic nature of its predecessor doxorubicin and how these properties shaped the pharmacology of mitoxantrone itself. Although mitoxantrone is firmly established as a DNA topoisomerase II poison within mammalian cells, it is now clear that the drug interacts with a much broader range of biological macromolecules both covalently and noncovalently. Here, we consider each of these interactions in the context of their wider biological relevance to cancer therapy and highlight how they may be exploited to further enhance the therapeutic value of mitoxantrone. In doing so, it is now clear that mitoxantrone is more than just another topoisomerase II poison.

Fas Signaling Promotes Gastric Cancer Metastasis through STAT3-Dependent Upregulation of Fascin

BACKGROUND

Fas signaling-activated signal transducers and activators of transcription 3 (STAT3) is required for Fascin upregulation. As an actin-bundling protein, Fascin can mediate gastric cancer (GC) cell migration.

METHODS

Gastric cancer AGS cells were treated with anti-Fas (5 μg/ml) for 2 h, in order to stimulate the activation of the Fas signaling. The in vitro migration of Fas signaling-activated AGS cells was assessed using Transwell chambers. The levels of Fascin and phosphorylated STAT3 were detected by Western blotting analyses. Nude mice were injected intravenously with AGS cells treated with anti-Fas or treated with STAT3 inhibitor without anti-Fas; tumor pulmonary metastases were measured. Fascin protein expression in tumor tissues was detected by immunohistochemistry. The Fas and Fascin mRNA levels in tumor tissues from patients with GC were measured by real-time PCR and their correlation was analyzed.

RESULTS

The activation of Fas signaling promoted cell migration and resulted in STAT3-dependent Fascin upregulation in AGS cells. STAT3 enhanced Fascin levels in vivo. Fascin was the mediator of Fas signaling-induced AGS cell migration in vitro and in vivo. Furthermore, there was a positive correlation between Fas and Fascin mRNA levels in tumor tissues from GC patients.

CONCLUSIONS

Fas signaling promotes GC metastasis through the STAT3/Fascin pathway, which may provide a new target for GC therapy.

Sensitizing cancer cells to TRAIL-induced death by micellar delivery of mitoxantrone

TNFα-related apoptosis-inducing ligand (TRAIL) induces death selectively in cancer cells. However, subpopulations of cancer cells are either resistant to or can develop resistance to TRAIL-induced death. As a result, strategies that overcome this resistance are currently under investigation. We have recently identified several US FDA-approved drugs with TRAIL-sensitization activity against prostate, breast and pancreatic cancer cells. Mitoxantrone, a previously unknown TRAIL sensitizer identified in the screen, was successfully encapsulated in methoxy-, amine- and carboxyl-terminated PEG-DSPE micelles in order to facilitate delivery of the drug to cancer cells. All three micelle types were extensively characterized for their physicochemical properties and evaluated for their ability to sensitize cancer cells to TRAIL-induced death. Our results indicate that micelle-encapsulated mitoxantrone can be advantageously employed in synergistic treatments with TRAIL, leading to a biocompatible delivery system and amplified cell killing activity for combination chemotherapeutic cancer treatments.

Original submitted 11 September 2012; Revised submitted 19 June 2013

Prediction of gene-based drug indications using compendia of public gene expression data and PubMed abstracts

The tremendous research effort on diseases and drug discovery has produced a huge amount of important biomedical information which is mostly hidden in the web. In addition, many databases have been created for the purpose of storing enormous amounts of information and high-throughput experiments related to drugs and diseases' effects on genes. Thus, developing an algorithm to integrate biological data from different sources forms one of the greatest challenges in the field of computational biology. Based on our belief that data integration would result in better understanding for the drug mode of action or the disease pathophysiology, we have developed a novel paradigm to integrate data from three major sources in order to predict novel therapeutic drug indications. Microarray data, biomedical text mining data, and gene interaction data have been all integrated to predict ranked lists of genes based on their relevance to a particular drug or disease molecular action. These ranked lists of genes have finally been used as a raw material for building a disease-drug connectivity map based on the enrichment between the up/down tags of a particular disease signature and the ranked lists of drugs. Using this paradigm, we have reported 13% sensitivity improvement in comparison with using microarray or text mining data independently. In addition, our paradigm is able to predict many clinically validated disease-drug associations that could not be captured using microarray or text mining data independently.

Alginate encapsulated cells secreting Fas-ligand reduce lymphoma carcinogenicity

Fas ligand (CD95L/APO-1) is considered as a potent anti-tumor agent due to its mediated cell death properties. We have designed a polymeric microencapsulation system, which encapsulates soluble FasL secreting cells. The encapsulated cells continuously release soluble FasL (sFasL) at the tumor site, while the device protects the encapsulated cells from the host immune system. The potential and efficacy of this system are demonstrated in vitro and in vivo for tumor inhibition. Polymeric microcapsules composed of Alginate Poly-l-lysine were optimized to encapsulate L5 secreting sFasL cells. The expression and anti-tumor activities of the sFasL were confirmed in vitro and tumor inhibition was studied in vivo in SCID mice bearing subcutaneous lymphoma tumors. In vitro, sFasL secreted by the encapsulated L5-sFasL cells was biologically active, inhibited proliferation and induced apoptotic cell death in Fas sensitive tumor cells. Mice injected with encapsulated L5-sFasL cells on the day of tumor injection or 10 days after tumor injection showed significant reduction in tumor volume, of 87% and 95%, respectively. Our findings show that encapsulated cells expressing sFasL can be used as a local device and efficiently suppress malignant Fas sensitive tumors with no side effects.

Antibody-based fusion proteins to target death receptors in cancer

Ideally, an immunotoxin should be inactive 'en route', acquire activity only after tumor cell surface binding and have no off-target effects towards normal cells. In this respect, antibody-based fusion proteins that exploit the tumor-selective pro-apoptotic death ligands sFasL and sTRAIL appear promising. Soluble FasL largely lacks receptor-activating potential, whereas sTRAIL is inactive towards normal cells. Fusion proteins in which an anti-tumor antibody fragment (scFv) is fused to sFasL or sTRAIL prove to be essentially inactive when soluble, while gaining potent anti-tumor activity after selective binding to a predefined tumor-associated cell surface antigen. Importantly, off-target binding by scFv:sTRAIL to normal cells showed no signs of toxicity. In this review, we highlight the rationale and perspectives of scFv:TRAIL/scFv:sFasL based fusion proteins for cancer therapy.

Interferon-gamma bolsters CD95/Fas-mediated apoptosis of astroglioma cells

In the present study, we investigated the mechanisms of the resistance to CD95-mediated cell death and the effects of interferon-gamma in modulating the susceptibility to CD95-induced apoptosis of human astroglioma cells. We found that interferon-gamma administration sensitized cancer cells to CD95-mediated apoptosis. The mechanism underlying this sensitization appeared to be associated with a framework of cell changes, including up-regulation of death receptor at the cell surface, pro-apoptotic molecule Bax and Bak over-expression and mitochondria hyperpolarization, as is known to be associated with cell sensitization to apoptosis. An involvement of the proteasome activity in the mechanism of sensitization by interferon-gamma was also detected, probably as a result of the differing expression of catalytic proteasome subunits. Taken together, these findings suggest that interferon-gamma could represent a promising candidate for modulating astroglioma cell apoptotic susceptibility.

Retrovirally transduced murine T lymphocytes expressing FasL mediate effective killing of prostate cancer cells

Adoptively transferred T cells possess anticancer activities partially mediated by T-cell FasL engagement of Fas tumor targets. However, antigen-induced T-cell activation and clonal expansion, which stimulates FasL activity, is often inefficient in tumors. As a gene therapy approach to overcome this obstacle, we have created oncoretroviral vectors to overexpress FasL or non-cleavable FasL (ncFasL) on murine T cells of a diverse T-cell receptor repertoire. Expression of c-FLIP was also engineered to prevent apoptosis of transduced cells. Retroviral transduction of murine T lymphocytes has historically been problematic, and we describe optimized T-cell transduction protocols involving CD3/CD28 co-stimulation of T cells, transduction on ice using concentrated oncoretrovirus, and culture with IL-15. Genetically modified T cells home to established prostate cancer tumors in vivo. Co-stimulated T cells expressing FasL, ncFasL and ncFasL/c-FLIP each mediated cytotoxicity in vitro against RM-1 and LNCaP prostate cancer cells. To evaluate the compatibility of this approach with current prostate cancer therapies, we exposed RM-1, LNCaP, and TRAMP-C1 cells to radiation, mitoxantrone, or docetaxel. Fas and H-2(b) expression were upregulated by these methods. We have developed a novel FasL-based immuno-gene therapy for prostate cancer that warrants further investigation given the apparent constitutive and inducible Fas pathway expression in this malignancy.