Hyperthermia (HT)--heating the tumor in the range of 40.0- 44.0 °C--combined with radiation (RT) and/or chemotherapy (CT) is a well proven treatment for malignant tumors. The improvement of the ...techniques for monitoring and adapting of the desired temperatures even in deep seated tumors has led to a renaissance of, now quality-controlled, HT in multimodal tumor therapy approaches. Randomized clinical trials have shown improved disease-free survival and local tumor control without an increase in toxicity for the combined treatment. In this review, we will focus on biological rationales of HT comprising direct cytotoxicity, systemic effects, chemosensitization, radiosensitization, and immune modulation. The latter is a prerequisite for the control of recurrent tumors and micrometastases. Immunogenic tumor cell death forms induced by HT will be introduced. Modulations of the cytotoxic properties of chemotherapeutic agents by HT as well as synergistic effects of HT with RT will be presented in the context of the main aims of anti-tumor therapy. Furthermore, modern techniques for thermal mapping like magnet resonance imaging will be outlined. The effectiveness of HT will be demonstrated by reviewing recent clinical trials applying HT in addition to CT and/or RT. We conclude that hyperthermia is a very potent radio- as well as chemosensitizer, which fosters the induction of immunogenic dead tumor cells leading to local and in special cases also to systemic tumor control.
Although cancer progression is primarily driven by the expansion of tumor cells, the tumor microenvironment and anti-tumor immunity also play important roles. Herein, we consider how tumors can ...become established by escaping immune surveillance and also how cancer cells can be rendered visible to the immune system by standard therapies such as radiotherapy or chemotherapy, either alone or in combination with additional immune stimulators. Although local radiotherapy results in DNA damage (targeted effects), it is also capable of inducing immunogenic forms of tumor cell death which are associated with a release of immune activating danger signals (non-targeted effects), such as necrosis. Necrotic tumor cells may result from continued exposure to death stimuli and/or an impaired phosphatidylserine (PS) dependent clearance of the dying tumor cells. In such circumstances, mature dendritic cells take up tumor antigen and mediate the induction of adaptive and innate anti-tumor immunity. Locally-triggered, systemic immune activation can also lead to a spontaneous regression of tumors or metastases that are outside the radiation field - an effect which is termed abscopal. Preclinical studies have demonstrated that combining radiotherapy with immune stimulation can induce anti-tumor immunity. Given that it takes time for immunity to develop following exposure to immunogenic tumor cells, we propose practical combination therapies that should be considered as a basis for future research and clinical practice. It is essential that radiation oncologists become more aware of the importance of the immune system to the success of cancer therapy.
Neutrophils are known to contribute in many aspects of tumor progression and metastasis. The presence of neutrophils or neutrophil-derived mediators in the tumor microenvironment has been associated ...with poor prognosis in several types of solid tumors. However, the effects of classical cancer treatments such as radiation therapy on neutrophils are poorly understood. Furthermore, the cellular composition and distribution of immune cells in the tumor is of increasing interest in cancer research and new imaging technologies allow to perform more complex spatial analyses within tumor tissues. Therefore, we aim to offer novel insight into intra-tumoral formation of cellular neighborhoods and communities in murine breast cancer. To address this question, we performed image mass cytometry on tumors of the TS/A breast cancer tumor model, performed spatial neighborhood analyses of the tumor microenvironment and quantified neutrophil-extracellular trap degradation products in serum of the mice. We show that irradiation with 2 × 8 Gy significantly alters the cellular composition and spatial organization in the tumor, especially regarding neutrophils and other cells of the myeloid lineage. Locally applied radiotherapy further affects neutrophils in a systemic manner by decreasing the serum neutrophil extracellular trap concentrations which correlates positively with survival. In addition, the intercellular cohesion is maintained due to radiotherapy as shown by E-Cadherin expression. Radiotherapy, therefore, might affect the epithelial–mesenchymal plasticity in tumors and thus prevent metastasis. Our findings underscore the growing importance of the spatial organization of the tumor microenvironment, particularly with respect to radiotherapy, and provide insight into potential mechanisms by which radiotherapy affects epithelial–mesenchymal plasticity and tumor metastasis.
Summary
Benign painful and inflammatory diseases have been treated for decades with low/moderate doses of ionizing radiation (LD‐X‐irradiation). Tissue macrophages regulate initiation and resolution ...of inflammation by the secretion of cytokines and by acting as professional phagocytes. Having these pivotal functions, we were interested in how activated macrophages are modulated by LD‐X‐irradiation, also with regard to radiation protection issues and carcinogenesis. We set up an ex‐vivo model in which lipopolysaccharide pre‐activated peritoneal macrophages (pMΦ) of radiosensitive BALB/c mice, mimicking activated macrophages under inflammatory conditions, were exposed to X‐irradiation from 0·01 Gy up to 2 Gy. Afterwards, the viability of the pMΦ, their transmigration and chemotaxis, the phagocytic behaviour, the secretion of inflammatory cytokines and underlying signalling pathways were determined. Exposure of pMΦ up to a single dose of 2 Gy did not influence their viability and phagocytic function, an important fact regarding radiation protection. However, significantly reduced migration, but increased chemotaxis of pMΦ after exposure to 0·1 or 0·5 Gy, was detected. Both might relate to the resolution of inflammation. Cytokine analyses revealed that, in particular, the moderate dose of 0·5 Gy applied in low‐dose radiotherapy for inflammatory diseases results in an anti‐inflammatory cytokine microenvironment of pMΦ, as the secretion of the proinflammatory cytokine interleukin (IL)‐1β was reduced and that of the anti‐inflammatory cytokine transforming growth factor (TGF)‐β increased. Further, the reduced secretion of IL‐1β correlated with reduced nuclear translocation of nuclear factor (NF)‐κB p65, starting at exposure of pMΦ to 0·5 Gy of X‐irradiation. We conclude that inflammation is modulated by LD‐X‐irradiation via changing the inflammatory phenotype of macrophages.
Alterations in the expression of apoptosis-related proteins, like the inhibitor of apoptosis (IAP) protein family, display a pivotal pathway by which cancer cells acquire resistance to therapeutic ...treatment. Among this family, survivin, the smallest and structural unique member, deserves growing attention due to its universal over-expression in human tumors, and its prominent role in disparate networks of cellular division, intracellular signaling and apoptosis. Several preclinical studies have demonstrated that targeting survivin expression by the use of small interfering RNAs, dominant negative mutants, antisense-oligonucleotides and small molecule repressors sensitized tumor cells towards chemotherapy and irradiation and reduced tumor growth potential. Due to these properties, survivin has been proposed as a molecular target for anticancer therapies. Recent studies further revealed that radio-sensitization achieved by survivin inhibition seems to be multifaceted and involves caspase-dependent and caspase-independent mechanisms. In general, an enhanced rate of apoptosis, and pronounced cell cycle arrest have been observed. More recently, a hampered DNA-damage response has been noted, indicating a distinct role of the protein in radiation-induced double strand break repair. These properties were linked to a nuclear import and physical interrelationship with members of the DNA-DSB repair machinery such as phospho-histone H2AX and DNA dependent Protein Kinase (DNA-PKcs). The applicability of survivin-driven strategies in clinical practice is currently under investigation as the first survivin inhibitors successfully entered phase I/II trials. Although these trials do not include radiation therapy at present, survivin inhibitors may represent a novel type of molecular antagonists to improve the effectiveness of radiation therapy or chemoradio-therapy.
One prerequisite that radiotherapy (RT) and chemotherapy (CT) result in anti-tumor immune responses is triggering of immunogenic cell death forms such as necroptosis. The latter is inducible by ...inhibition of apoptosis with the pan-caspase inhibitor zVAD-fmk. The design of multimodal therapies that overcome melanoma's resistance to apoptosis is a big challenge of oncoimmunology. As hints exist that immune stimulation by hyperthermia (HT) augments the efficacy of melanoma therapies and that tumors can be sensitized for RT with zVAD-fmk, we asked whether combinations of RT with dacarbazine (DTIC) and/or HT induce immunogenic melanoma cell death and how this is especially influenced by zVAD-fmk. Necroptosis was inducible in poorly immunogenic B16-F10 melanoma cells and zVAD-fmk generally increased melanoma cell necrosis concomitantly with the release of HMGB1. Supernatants (SNs) of melanoma cells whose cell death was modulated with zVAD-fmk induced an upregulation of the activation markers CD86 and MHCII on macrophages. The same was seen on dendritic cells (DCs), but only when zVAD-fmk was added to multimodal tumor treatments including DTIC. DCs of MyD88 KO mice and DCs incubated with SNs containing apyrase did not increase the expression of these activation markers on their surface. The in vivo experiments revealed that zVAD-fmk decreases the tumor growth significantly and results in a significantly reduced tumor infiltration of Tregs when added to multimodal treatment of the tumor with RT, DTIC and HT. Further, a significantly increased DC and CD8+ T-cell infiltration into the tumor and in the draining lymph nodes was induced, as well as an increased expression of IFNγ by CD8+ T cells. However, zVAD-fmk did not further reduce tumor growth in MyD88 KO mice, mice treated with apyrase or RAG KO mice. We conclude that HMGB1, nucleotides and CD8+ T cells mediate zVAD-fmk induced anti-melanoma immune reactions in multimodal therapy settings.
Career situation of first and presenting authorPost-doctoral fellow.IntroductionRheumatoid arthritis (RA) is a chronic, progressive, inflammatory autoimmune disease that mainly affects the joints ...with its hallmarks being synovial inflammation followed by cartilage and bone destruction. There are a plethora of treatment options available, however, not all patients respond properly. In these patients it is crucial to slow down bone loss and inflammation in a timely manner to prevent further damage. Here, a therapy with low-dose ionizing radiation, the so called low-dose radiotherapy (LD-RT), could be an additional option. Detailed knowledge on the underlying mechanisms of reduced bone destruction and immune-mediated pain levels in patients following LD-RT is still scarce. We already showed that LD-RT locally slows down disease progression in human TNFα transgenic (hTNFα tg) animals by mainly having an impact on bone metabolism.ObjectivesWe now aim to take a closer look on systemic immune-mediated effects of LD-RT in both, hTNFα tg mice, as a cytokine mediated model, and in the KRN serum transfer model, as an example for arthritogenic antibody dependence.MethodshTNFα tg or serum-injected C57Bl/6 mice were locally irradiated with a single dose per fraction of 0.5Gy. After an observation period of 7 days (serum-injected mice) or 30 days (hTNFα-tg mice), blood, bone marrow as well as hind paws and synovial fluid was taken and analyzed using multicolor flow cytometry or histomorphometry.ResultsTreatment of hind paws of serum-injected C57Bl/6 mice with 1 × 0.5 Gy resulted in a systemic immune modulation. In the peripheral blood, an increase of eosinophils and a decrease of B cells and NK cells were observed. In the bone marrow, the prominent alteration was a shift from CD8+ to CD4+ T cells in both, the irradiated and non-irradiated leg. Furthermore, dendritic cells were decreased. In hTNFα tg animals, inflammation was modulated in a systemic manner after local LD-RT, while bone protection was a local effect.ConclusionsWe conclude that LD-RT is not only a valuable tool for locally reducing inflammation and bone loss in the affected joints, but also has beneficial systemic immune-mediated effects. The observed immune modulations in the peripheral blood were similar to those observed for patients treated with LD-RT within the observational IMMO-LDRT01 study (NCT02653079). In the future, placebo-controlled studies with high patient numbers are desirable to clinically prove LD-RT as therapy for RA.AcknowledgementsSupported by the German Federal Ministry of Education and Research (GREWIS, 02NUK017G and GREWIS-alpha, 02NUK050E).Disclosure of InterestNone declared.
Background and purpose
To evaluate the long-term efficacy of pain reduction by two dose fractionation schedules used for low-dose radiotherapy of painful elbow syndrome.
Patients and methods
Between ...February 2006 and February 2010, 199 evaluable patients were recruited for this prospective trial. All patients received low-dose orthovoltage radiotherapy. One course consisted of 6 fractions in 3 weeks. In the case of insufficient pain remission after 6 weeks, a second course was administered. Patients were randomly assigned to one of two groups to receive single doses of either 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before radiotherapy, as well as immediately after (early response), 6 weeks after (delayed response) and approximately 3 years after (long-term response) completion of radiotherapy using a questionnaire-based visual analogue scale (VAS) and a comprehensive pain score (CPS).
Results
Median follow-up was 35 months (range 9–57 months). The overall early, delayed and long-term response rates for all patients were 80, 90 and 94 %, respectively. The mean VAS scores before treatment and those for early, delayed and long-term response in the 0.5- and 1.0-Gy groups were 59.6 ± 20.2 and 55.7 ± 18.0 (p = 0.46); 32.1 ± 24.5 and 34.4 ± 22.5 (p = 0.26); 27.0 ± 27.7 and 23.5 ± 21.6 (p = 0.82) and 10.7 ± 15.0 and 21.5 ± 26.9 (p = 0.12), respectively. The mean CPS values before treatment and those for early, delayed and long-term response were 8.7 ± 2.9 and 8.1 ± 3.1 (p = 0.21); 4.5 ± 3.2 and 5.0 ± 3.4 (p = 0.51); 3.9 ± 3.6 and 2.8 ± 2.8 (p = 0.19) and 1.5 ± 2.3 and 2.4 ± 3.5 (p = 0.27), respectively. No significant differences in the quality of the long-term response were found between the 0.5- and 1.0-Gy arms (p = 0.28).
Conclusion
Low-dose radiotherapy is an effective treatment for the management of benign painful elbow syndrome. For radiation protection reasons, the dose for a radiotherapy series should not exceed 3.0 Gy.
Background
In this exploratory study, the impact of local irradiation on systemic changes in stress and immune parameters was investigated in eight patients treated with intensity-modulated radiation ...therapy (IMRT) or stereotactic ablative body radiotherapy (SABR) for prostate adenocarcinoma to gain deeper insights into how radiotherapy (RT) modulates the immune system.
Patients and methods
RT-qPCR, flow cytometry, metabolomics, and antibody arrays were used to monitor a panel of stress- and immune-related parameters before RT, after the first fraction (SABR) or the first week of treatment (IMRT), after the last fraction, and 3 weeks later in the blood of IMRT (
N
= 4) or SABR (
N
= 4) patients. Effect size analysis was used for comparison of results at different timepoints.
Results
Several parameters were found to be differentially modulated in IMRT and SABR patients: the expression of
TGFB1
,
IL1B
, and
CCL3
genes; the expression of HLA-DR on circulating monocytes; the abundance and ratio of phosphatidylcholine and lysophosphatidylcholine metabolites in plasma. More immune modulators in plasma were modulated during IMRT than SABR, with only two common proteins, namely GDF-15 and Tim‑3.
Conclusion
Locally delivered RT induces systemic modulation of the immune system in prostate adenocarcinoma patients. IMRT and SABR appear to specifically affect distinct immune components.
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