Induction of interleukin-1β by mouse mammary tumor irradiation promotes triple negative breast cancer cells invasion and metastasis development

Combination of radiotherapy and immunotherapy in duality with the protumoral action of radiation

Radiotherapy is widely used to treat various cancers. Its combination with immune checkpoint inhibitors is intensively studied preclinically and clinically. Although the first results were very encouraging, the number of patients who respond positively remains low, and the therapeutic benefit is often temporary. This review summarizes how radiation can stimulate an antitumor immune response and its combination with immunotherapy based on inhibiting immune checkpoints. We will provide an overview of radiotherapy parameters that should be better controlled to avoid downregulating the antitumor immune response. The low response rate of combining radiotherapy and immunotherapy could, at least in part, be caused by the stimulation of cancer cell invasion and metastasis development that occur at similar doses and number of radiation fractions. To end on a positive note, we explore how a targeted inhibition of the inflammatory cytokines induced by radiation with a cyclooxygenase-2 inhibitor could both support an antitumor immune response and block radiation-induced metastasis formation.

Key Factor Regulating Inflammatory Microenvironment, Metastasis, and Resistance in Breast Cancer: Interleukin-1 Signaling

Breast cancer is one of the top-ranked cancers for incidence and mortality worldwide. The biggest challenges in breast cancer treatment are metastasis and drug resistance, for which work on molecular evaluation, mechanism studies, and screening of therapeutic targets is ongoing. Factors that lead to inflammatory infiltration and immune system suppression in the tumor microenvironment are potential therapeutic targets. Interleukin-1 is known as a proinflammatory and immunostimulatory cytokine, which plays important roles in inflammatory diseases. Recent studies have shown that interleukin-1 cytokines drive the formation and maintenance of an inflammatory/immunosuppressive microenvironment through complex intercellular signal crosstalk and tight intracellular signal transduction, which were found to be potentially involved in the mechanism of metastasis and drug resistance of breast cancer. Some preclinical and clinical treatments or interventions to block the interleukin-1/interleukin-1 receptor system and its up- and downstream signaling cascades have also been proven effective. This study provides an overview of IL-1-mediated signal communication in breast cancer and discusses the potential of IL-1 as a therapeutic target especially for metastatic breast cancer and combination therapy and current problems, aiming at enlightening new ideas in the study of inflammatory cytokines and immune networks in the tumor microenvironment.

Reconciling two opposing effects of radiation therapy: stimulation of cancer cell invasion and activation of anti-cancer immunity

PURPOSE

The damage caused by radiation therapy to cancerous and normal cells inevitably leads to changes in the secretome profile of pro and anti-inflammatory mediators. The inflammatory response depends on the dose of radiation and its fractionation, while the inherent radiosensitivity of each patient dictates the intensity and types of adverse reactions. This review will present an overview of two apparently opposite reactions that may occur after radiation treatment: induction of an antitumor immune response and a protumoral response. Emphasis is placed on the molecular and cellular mechanisms involved.

CONCLUSIONS

By understanding how radiation changes the balance between anti- and protumoral effects, these forces can be manipulated to optimize radiation oncology treatments.

The Irradiated Brain Microenvironment Supports Glioma Stemness and Survival via Astrocyte-Derived Transglutaminase 2

The tumor microenvironment plays an essential role in supporting glioma stemness and radioresistance. Following radiotherapy, recurrent gliomas form in an irradiated microenvironment. Here we report that astrocytes, when pre-irradiated, increase stemness and survival of cocultured glioma cells. Tumor-naïve brains increased reactive astrocytes in response to radiation, and mice subjected to radiation prior to implantation of glioma cells developed more aggressive tumors. Extracellular matrix derived from irradiated astrocytes were found to be a major driver of this phenotype and astrocyte-derived transglutaminase 2 (TGM2) was identified as a promoter of glioma stemness and radioresistance. TGM2 levels increased after radiation in vivo and in recurrent human glioma, and TGM2 inhibitors abrogated glioma stemness and survival. These data suggest that irradiation of the brain results in the formation of a tumor-supportive microenvironment. Therapeutic targeting of radiation-induced, astrocyte-derived extracellular matrix proteins may enhance the efficacy of standard-of-care radiotherapy by reducing stemness in glioma. SIGNIFICANCE: These findings presented here indicate that radiotherapy can result in a tumor-supportive microenvironment, the targeting of which may be necessary to overcome tumor cell therapeutic resistance and recurrence. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/8/2101/F1.large.jpg.

Nutritional supplements in combination with chemotherapy or targeted therapy reduces tumor progression in mice bearing triple-negative breast cancer

The potential anti-cancer properties of selenium (Se) and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) have been documented. However, few studies have been conducted examining anti-tumor effects of nutritional supplements (NS) containing Se and EPA/DHA in combination with anti-cancer agents, such as taxol (Tax), adriamycin (Adr), and avastin (Ava). Compared with triple-negative breast cancer (TNBC)-bearing positive control (TB) mice, a low dose of Tax, Adr, and Ava decreased tumor size and the incidence of metastasis in TB-Tax, TB-Adr, and TB-Ava groups. Combination treatment with anti-cancer agent and NS (2.7 μg Se and 5.1 mg EPA/3.7 mg DHA/g) induced additional decreases in TB-Tax-NS, TB-Adr-NS, and TB-Ava-NS groups. Th1-associated cytokines were increased, and Th2-type cytokines were decreased significantly in TB mice with combination treatment than that of anti-cancer agent treatment alone. Combination treatment with anti-cancer agents and NS has also been shown to further increased tumor malondialdehyde (MDA) levels, lowered hypoxia-inducible factor (HIF)-1α, angiogenic markers (vascular endothelial growth factor [VEGF] and CD31) and metastatic potential, as well as reduced heat shock proteins, receptor tyrosine kinase AXL, and surface markers of cancer stem cells, and increased apoptotic proteins. For immune checkpoint molecules, combination treatment was associated with a greater decrease in programmed cell death ligand-1 (PD-L1) in both tumors and mammary glands, but PD-1 level in primary tumors was increased. Our results suggest that combination treatment with low-dose anti-cancer agents (Tax, Adr, and Ava) and oral supplementation of Se/ EPA/DHA significantly decreased tumor growth and metastatic progression in TNBC mice through multiple anti-tumor mechanisms.

Low energy (6-18 eV) electron scattering from condensed thymidine (dT) III: absolute electronic excitation cross sections

Absolute cross sections (CSs) for electronic excitation by low-energy electron (LEE) scattering, from condensed thymidine (dT) in the 6-18 eV incident energy range, were measured by high-resolution electron energy loss spectroscopy (HREELS). Various electron energy loss (EEL) spectra were acquired using 1 ML of dT condensed on a multilayer film of Ar held at about 20 K under ultra-high vacuum (∼1 × 10-11 Torr). dT is one of the most complex DNA constituents to be studied by HREELS and these spectra provide the first LEE energy-loss data for electronic excitation of a nucleoside. CSs for transitions to the states 13A', 13A'', 23A', 21A', 33A', 23A'', 43A', 33A'', 53A' and 51A' of dT were extracted from the EEL spectra. These states correlate to those previously measured for the thymine moiety. Two broad resonances are observed in the energy dependence of the CSs at around 8 and 10 eV; these energies are close to those found in earlier gas- and solid-phase studies on the interaction of LEEs with dT, thymine and related molecules. A quantitative comparison between the electronic CSs of dT and those of thymine and tetrahydrofuran indicates that no variation is induced in the electronic CSs of thymine upon chemically binding to a deoxyribose group.

CSCs in Breast Cancer-One Size Does Not Fit All: Therapeutic Advances in Targeting Heterogeneous Epithelial and Mesenchymal CSCs

Unlike other breast cancer subtypes, triple-negative breast cancer (TNBC) has no specific targets and is characterized as one of the most aggressive subtypes of breast cancer that disproportionately accounts for the majority of breast cancer-related deaths. Current conventional chemotherapeutics target the bulk tumor population, but not the cancer stem cells (CSCs) that are capable of initiating new tumors to cause disease relapse. Recent studies have identified distinct epithelial-like (E) ALDH⁺ CSCs, mesenchymal-like (M) CD44⁺/CD24^- CSCs, and hybrid E/M ALDH⁺/CD44⁺/CD24^- CSCs. These subtypes of CSCs exhibit differential signal pathway regulations, possess plasticity, and respond differently to treatment. As such, co-inhibition of different subtypes of CSCs is key to viable therapy. This review serves to highlight different pathway regulations in E and M CSCs in TNBC, and to further describe their role in disease progression. Potential inhibitors targeting E and/or M CSCs based on clinical trials are summarized for further investigation. Since future research needs to adopt suitable tumor models and take into account the divergence of E and M CSCs for the development of effective treatments, TNBC models for clinically translatable studies are further discussed.

Radiobiological quantities in proton-therapy: Estimation and validation using Geant4-based Monte Carlo simulations

PURPOSE

The Geant4 Monte Carlo simulation toolkit was used to reproduce radiobiological parameters measured by irradiating three different cancerous cell lines with monochromatic and clinical proton beams.

METHODS

The experimental set-up adopted for irradiations was fully simulated with a dedicated open-source Geant4 application. Cells survival fractions was calculated coupling the Geant4 simulations with two analytical radiobiological models: one based on the LEM (Local Effect Model) approach and the other on a semi-empirical parameterisation. Results was evaluated and compared with experimental data.

RESULTS AND CONCLUSIONS

The results demonstrated the Geant4 ability to reproduce radiobiological quantities for different cell lines.

Serum amyloid A predisposes inflammatory tumor microenvironment in triple negative breast cancer

Acute-phase proteins (APPs) are associated with a variety of disorders such as infection, inflammatory diseases, and cancers. The signature profile of APPs in breast cancer (BC) is poorly understood. Here, we identified serum amyloid A (SAA) for proinflammatory predisposition in BC through the signature profiles of APPs, interleukin (IL) and tumor necrosis factor (TNF) superfamily using publicly available datasets of tumor samples and cell lines. Triple-negative breast cancer (TNBC) subtype highly expressed SAA1/2 compared to HER2, luminal A (LA) and luminal B (LB) subtypes. IL1A, IL1B, IL8/CXCL8, IL32 and IL27RA in IL superfamily and CD70, TNFSF9 and TNFRSF21 in TNF superfamily were highly expressed in TNBC compared to other subtypes. SAA is restrictedly regulated by nuclear factor (NF)-κB and IL-1β, an NF-κB activator highly expressed in TNBC, increased the promoter activity of SAA1 in human TNBC MDA-MB231 cells. Interestingly, two κB-sites contained in SAA1 promoter were involved, and the proximal region (-96/-87) was more critical than the distal site (-288/-279) in regulating IL-1β-induced SAA1. Among the SAA receptors, TLR1 and TLR2 were highly expressed in TNBC. Cu-CPT22, TLR1/2 antagonist, abrogated IL-1β-induced SAA1 promoter activity. In addition, SAA1 induced IL8/CXCL8 promoter activity, which was partially reduced by Cu-CPT22. Notably, SAA1/2, TLR2 and IL8/CXCL8 were associated with a poor overall survival in mesenchymal-like TNBC. Taken together, IL-1-induced SAA via NF-κB-mediated signaling could potentiate an inflammatory burden, leading to cancer progression and high mortality in TNBC patients.

Improved prediction of breast cancer outcome by identifying heterogeneous biomarkers

Motivation

Identification of genes that can be used to predict prognosis in patients with cancer is important in that it can lead to improved therapy, and can also promote our understanding of tumor progression on the molecular level. One of the common but fundamental problems that render identification of prognostic genes and prediction of cancer outcomes difficult is the heterogeneity of patient samples.

Results

To reduce the effect of sample heterogeneity, we clustered data samples using K-means algorithm and applied modified PageRank to functional interaction (FI) networks weighted using gene expression values of samples in each cluster. Hub genes among resulting prioritized genes were selected as biomarkers to predict the prognosis of samples. This process outperformed traditional feature selection methods as well as several network-based prognostic gene selection methods when applied to Random Forest. We were able to find many cluster-specific prognostic genes for each dataset. Functional study showed that distinct biological processes were enriched in each cluster, which seems to reflect different aspect of tumor progression or oncogenesis among distinct patient groups. Taken together, these results provide support for the hypothesis that our approach can effectively identify heterogeneous prognostic genes, and these are complementary to each other, improving prediction accuracy.

Availability and implementation

https://github.com/mathcom/CPR.

Contact

jgahn@inu.ac.kr.

Supplementary information

Supplementary data are available at Bioinformatics online.

Radiation therapy-induced metastasis: radiobiology and clinical implications

Radiation therapy is an effective means of achieving local control in a wide range of primary tumours, with the reduction in the size of the tumour(s) thought to mediate the observed reductions in metastatic spread in clinical trials. However, there is evidence to suggest that the complex changes induced by radiation in the tumour environment can also present metastatic risks that may counteract the long-term efficacy of the treatment. More than 25 years ago, several largely theoretical mechanisms by which radiation exposure might increase metastatic risk were postulated. These include the direct release of tumour cells into the circulation, systemic effects of tumour and normal tissue irradiation and radiation-induced changes in tumour cell phenotype. Here, we review the data that has since emerged to either support or refute these putative mechanisms focusing on how the unique radiobiology underlying modern radiotherapy modalities might alter these risks.

Tumor Cell Invasion Induced by Radiation in Balb/C Mouse is Prevented by the Cox-2 Inhibitor NS-398

Radiation stimulates the expression of inflammatory mediators known to increase cancer cell invasion. Therefore, it is important to determine whether anti-inflammatory drugs can prevent this adverse effect of radiation. Since cyclooxygenase-2 (COX-2) is a central player in the inflammatory response, we performed studies to determine whether the COX-2 inhibitor NS-398 can reduce the radiation enhancement of cancer cell invasion. Thighs of Balb/c mice treated with NS-398 were irradiated with either daily fractions of 7.5 Gy for five consecutive days or a single 30 Gy dose prior to subcutaneous injection of nonirradiated MC7-L1 mammary cancer cells. Five weeks later, tumor invasion, blood vessel permeability and interstitial volumes were assessed using magnetic resonance imaging (MRI). Matrix metalloproteinase-2 (MMP-2) was measured in tissues by zymography at 21 days postirradiation. Cancer cell invasion in the mouse thighs was increased by 12-fold after fractionated irradiations (5 × 7.5 Gy) and by 17-fold after a single 30 Gy dose of radiation. This stimulation of cancer cell invasion was accompanied by a significant increase in the interstitial volume and a higher level of the protease MMP-2. NS-398 treatment largely prevented the stimulation of cancer cell invasion, which was associated with a reduction in interstitial volume in the irradiated thighs and a complete suppression of MMP-2 stimulation. In conclusion, this animal model using MC7-L1 cells demonstrates that radiation-induced cancer cell invasion can be largely prevented with the COX-2 inhibitor NS-398.

EMT and MET: necessary or permissive for metastasis?

Epithelial‐to‐mesenchymal transition (EMT) and its reverse mesenchymal‐to‐epithelial transition (MET) have been suggested to play crucial roles in metastatic dissemination of carcinomas. These phenotypic transitions between states are not binary. Instead, carcinoma cells often exhibit a spectrum of epithelial/mesenchymal phenotype(s). While epithelial/mesenchymal plasticity has been observed preclinically and clinically, whether any of these phenotypic transitions are indispensable for metastatic outgrowth remains an unanswered question. Here, we focus on epithelial/mesenchymal plasticity in metastatic dissemination and propose alternative mechanisms for successful dissemination and metastases beyond the traditional EMT/MET view. We highlight multiple hypotheses that can help reconcile conflicting observations, and outline the next set of key questions that can offer valuable insights into mechanisms of metastasis in multiple tumor models.

Exosomes from Melatonin Treated Hepatocellularcarcinoma Cells Alter the Immunosupression Status through STAT3 Pathway in Macrophages

Immunosuppression is a significant factor in the progression of tumor invasion and metastasis. Melatonin, a well-known hormone, has certain cytotoxic and immune regulatory effects to inhibit tumor function. Exosomes are small membrane vesicles released by many kinds of cells, which contain different macromolecules, such as mRNAs and microRNAs (miRNAs), and proteins that can mediate communications between cells. Tumor-derived exosomes may cause immunosuppression, however, it is unknown whether melatonin can attenuate an immunosuppressive status by altering the function of tumor-derived exosomes. In the present study, we evaluated the effects of hepatocellularcarcinoma-derived exosomes (Exo-con) and exosomes derived from hepatocellularcarcinoma cells treated with 0.1 mM melatonin (Exo-MT), on the expression of inflammatory factors and programmed death ligand 1(PD-L1) by co-culturing Exo-con and Exo-MT, respectively, with macrophages differentiated from THP-1 cells or RAW264.7 cells. Our in vitro results indicate that Exo-MT can downregulate the expression of PD-L1 on macrophages while Exo-con can upregulate the expression of PD-L1 through flow cytometry and immunofluorescence analysis. In addition, Exo-con upregulates the secretion of cytokines, such as IL-6, IL-10, IL-1β, and TNF-α in macrophages. Accordingly, Exo-MT could attenuate the high expression of these inflammatory cytokines. Furthermore, in vivo experiments confirmed the results found in vitro. PD-L1 expression and cytokine secretion were lower in the Exo-MT group compared with those in the Exo-con group. Working to identify a specific mechanism, our research shows that Exo-MT decreases STAT3 activation compared to the Exo-con group. In summary, we found exosomes from melatonin treated hepatocellularcarcinoma cells alters the immunosupression status through STAT3 pathway in macrophages. Our study may provide a new avenue to investigate the mechanisms of melatonin in regulating an immunosuppressive status.